• Relationship between different maceral contents and molecular structure parameters of Dabaodang coal

    LI Zhen;ZHAO Kai;ZHU Zhanglei;CHANG Jing;YANG Chao;ZHANG Huaiqing;ZHANG Ningning;QU Jingzhou;SHANG Yingze;College of Chemistry and Chemical Engineering,Xi′an University of Science and Technology;Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources;

    In order to explore the molecular structure of macerals and the internal relationship between their contents, seven samples of coal macerals with different contents were separated bysink-float centrifuge method, taking low metamorphic high inertite coal samples from Dabaotang Coal mine, Shenfu Coalfield, Jurassic period as the research object. Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),~(13)C solid state nuclear magnetic resonance(~(13)C-NMR) were used to characterize the physical structure, chemical structure and semi-quantitative calculation, and a series of structural parameters were obtained. FTIR results show that more vitrinite resulted in more and shorter aliphatic chains, higher degree of branched chain, and higher inertinite content resulte in higher aroma. XRD results show that the aromatic layer spacing(d_(002)),the elongation(L_a),stacking height(L_c) and the aromatic layer number(N_c) of different coal macerals are only slightly different with the increase of vitrinite content. XPS carbon analysis results show that with the increase of vitrinite content, the sum proportion of C—C and C—H content gradually increase, which is related to the presence of a large number of aliphatic structures in vitrinite. The mass fraction of ether carbon/phenolic carbon(C—O) is larger when inertinite is higher, which is due to the higher aromatic degree of inertinite. ~(13)C-NMR analysis show that f_a and f ′_a are positively correlated with vitrinite content, while f_(al) is negatively correlated with vitrinite content, and reach the optimal prediction model for vitrinite content. These conclusions provide a large amount of information for the molecular structure of maceral with different contents at present, and also provide an important supplement for understanding the correlation between maceral and its contents. It is hoped that the obtained information can be used in the efficient and clean conversion and utilization of coal. It provides a method for predicting the content of maerals.

    2023 S2 v.29 [Abstract][OnlineView][Download 2478K]
  • Formation mechanism of sodium-containing minerals

    XU Tianyao;FU Peifang;CLP Huachuang (Suzhou) Power Technology Research Co., Ltd.;School of Energy and Power Engineering, Huazhong University of Science & Technology;

    The reserve of Zhundong coal is abundant, but the high content of sodium restricts the large-scale utilization of Zhundong coal. The predecessors have studied a lot of methods for the treatment of sodium in Zhundong coal, but most of the studies are aimed at the situation at lower temperatures and the migration and transformation characteristics of sodium. The formation mechanism of sodium-containing minerals such as nepheline at high temperature and their sodium retention rate are still unclear. The mechanism of the reaction between kaolin, other silica-alumina minerals and sodium to form sodium-containing minerals was studied by using a tube furnace experimental bench in the temperature range of 700-1 400 ℃. The results show that the reactivity of kaolin with Na is higher than that of the mixed additives of silica and alumina, the temperature of nepheline formation is lower, but it cannot exist stably at high temperature, and the sodium retention rate can reach up to 81.54%; The reactivity of NaSiAl sample is slightly lower, but sodium can be fixed in the sample in the form of nepheline at 800-1 400 ℃, and the sodium retention rate sample can reach 69.73%; The temperature segment at which the entropy yield jumps abruptly reflects the structural change of the system, and the point where the first derivative of the entropy yield is zero indicates the equilibrium point of the reaction.

    2023 S2 v.29 [Abstract][OnlineView][Download 2275K]
  • X-ray recognition mechanism of coal gangue based on graphite and clay minerals

    YANG Chenguang;YIN Jianqiang;ZHU Jinbo;WANG Chao;WU Liqin;LIU Chengwen;ZHOU Zheng;School of Materials Science and Engineering,Anhui University of Science and Technology;

    "Gray value" is an important recognition feature in photoelectric intelligent coal and gangue separation. In the actual separation, the complex underground environment will seriously affect the gray characteristics of coal gangue based on visible light separation, such as water attached to the surface of coal gangue and coal ash in the air, and the use of invisible light separation will produce a "thickness effect". The reason is that the density and thickness of each mineral component in coal and gangue are different, so that the gray characteristics of thicker coal and thinner gangue can not be separated. In order to solve these problems, the relationship between the thickness of different minerals and gray value was studied. First of all, based on the analysis of the mineral composition of coal and gangue, four single minerals of graphite, quartz, kaolin and montmorillonite and mixed mineral samples were made. Secondly, the concept of pixel volume electron number(N_(e-p)) was put forward, and the relationship between N_(e-p) and thickness is obtained. The gray function relationship between single mineral and mixed mineral was established. After verification, the Pearson correlation between the output gray value and the measured gray value is more than 98%. Finally, the model of mixed minerals was deduced to a single model. The results show that adding another mineral to a single mineral will change its original X-ray absorption coefficient, which has nothing to do with the amount of minerals added. Each ore can be distinguished in the range of 7-21mm thickness, which reveals the mechanism of X-ray identification of coal and gangue.

    2023 S2 v.29 [Abstract][OnlineView][Download 2223K]
  • Microstructure analysis of coal in Ningdong base based on modern instruments

    ZHAO Junping;ZHOU Weiguo;ZHU Chaoyang;CHEN Shujun;Guohua (Ningxia) New Energy Co., Ltd.;State Grid Energy Hefeng Coal Power Co., Ltd.;

    Ningdong coal reserves are considerable, and the low-carbon and efficient utilization of coal based on the dual-carbon background is an important transformation problem facing Ningdong coal. The correct understanding of the coal micro-structure is the key to the low-carbon, efficient and clean utilization of coal. In this paper, five kinds of coal in Ningdong typical mining area are selected as the research object, using X-ray diffraction(XRD), infrared spectrum(FTIR) and other modern instrument spectroscopy to analyze the microstructure of Ningdong coal(Raman). On this basis, the simplified structure characteristics of Ningdong coal are established. The results show that the difference in molecular structure between different coal species mainly exists in the size of fat carbon and carbon layer structure; with the increase of H/C, the fat chain(I_2) on the carbon layer structure in coal increases, the transverse dimension(L_a) decreases, the condensation reaction makes the carbon layer spacing(d_(002)) increases and the height(L_c) decreases. The molecular structure of Ningdong coal can be simplified to consists of short-range carbon layers, whose small sizes are connected by amorphous or aliphatic carbon. The peak of the X diffraction data calculates the relative amorphous or aliphatic carbon content(1/f_a), the peak 002 calculates the layer spacing(d_(002)) and layer height(L_c), the Raman structure parameters calculate the transverse dimension(L_a), and the infrared structure parameters calculate the relative amount of functional groups hanging on the carbon layer(I_2). The above research results provide a theoretical basis for the low-carbon, clean and efficient development and utilization of coal resources in Ningdong.

    2023 S2 v.29 [Abstract][OnlineView][Download 2033K]
  • Mineralogical characteristics of CFB boiler fly ash process

    DENG Yusheng;ZHENG Wenkai;LU Xiaobin;YANG Yong;ZHANG Zhenxing;WANG Haifeng;Thermoelectricity Division,Sinopec Maoming Petrochemical Co.,Ltd.;School of Environmental Science and Engineering,Guangdong University of Technology;School of Chemical Engineering,China University of Mining and Technology;

    Fly ash is generally used for cement and various building materials preparation. CFB boiler fuel is widely adaptable, the carbon content in fly ash is high after mixing and burning various kinds of poor-quality fuels, and exploring the mineralogical properties of fly ash process is the basis of its comprehensive utilization. The process mineralogical properties of the fly ash from the No.1,No.2 and No.4 CFB boilers of Maoming Petrochemical were analyzed in depth as examples. The analysis results show that the particle size of the three types of fly ash is fine,-0.074 mm particle size is above 90%,and the burn loss is more than 10%,which is not conducive to the utilization of building materials. With the increase of density level, the burn loss gradually decreases. The main components of fly ash are Al_2O_3,SiO_2,SO_3,CaO and Fe_2O_3,with the total content over 80%,and a small amount of Na_2O,MgO,K_2O,etc. are also interspersed. XRD analysis show that the main mineral composition of fly ash was CaO,CaSO_4 and SiO_2. SEM-EDS,XPS and EMPA analysis show that amorphous particles of fly ash are predominant, with fewer spherical particles, and the main elements on the surface of the particles are C,O,Ca, S,Si and Al. The shapes of the adsorption and desorption curves of the three types of fly ash are consistent, the specific surface areas of No.1 and No.2 fly ash are similar, the pores are mainly medium micropores, and the specific surface area of No.4 fly ash reaches 20.915 9 m~2/g with an average pore size of 6.953 9 nm. Through in-depth analysis of the mineralogical properties of the three types of fly ash processes, data support is provided for their resourceful and comprehensive utilization.

    2023 S2 v.29 [Abstract][OnlineView][Download 2534K]
  • Effect of particle size on mineral phases and reactivity of fly ash

    LI Qiao;DONG Yang;ZHUO Jinde;LIANG Wenbin;JI Hongwei;National Institute of Clean-and-Low-Carbon Energy,CHN Energy Group;

    Because of different coal type, pretreatment and combustion process, fly ash particles have differences in particle size, chemical composition and mineral phase.The relationship between particle size, chemical composition, and mineral phase was studied by analytical methods of XRF and XRD. The result shows that network formation and network modifier have similar content in fly ash particles with different sizes. The activity of fly ash cannot be estimated by contents of network formation and modifier. Meanwhile, metallic element contents show continuous enrichment as fly ash particle size decreases. As a result, it will be a more effective method to separate small particles before extracting rare metal from fly ash. The result of XRD shows that small particle has low degree of crystallinity while large particles show higher degree. This also indicates that small particles have higher reactivity. As comparison with the large particles, the small particles contain active constituents such as calcium sulfate and potassium aluminium silicate. It proves that particle size of fly ash has obvious influence to its composition and reactivity.

    2023 S2 v.29 [Abstract][OnlineView][Download 1880K]
  • Distribution characteristics and enrichment experiment of organic matter in oil shale of West open-pit mine

    SONG Junchao;HU Bingsheng;SHI Changliang;China Coal Technology & Industry Group Tangshan Research Institute Co.,Ltd.;Hebei Province Coal Washing & Engineering Technology Research Center;College of Chemistry and Chemical Engineering,Henan Polytechnic University;

    Oil shale is a kind of unconventional oil and natural gas resources. Because of its high utilization value of organic matter, it has been listed as an important alternative energy in the 21st century.The density distribution characteristics of organic matter in oil shale was analyzed, and the flotation behavior and enrichment mechanism of initially enriched organic matter products were discussed. The research results show that the oil shale is a mineral with high ash content and high oil content. In the original sample, the proportion of larger block size more than 13 mm is relatively high, and the proportion of products with density less than 2.0 kg/L is relatively low, but the oil content is relatively high. During flotation process of 2.0 kg/L sample, the slurry concentration, the amount of collector and the amount of foaming agent have a great impact on its flotation efficiency. When the slurry concentration is 80 g/L, the amount of collector is 1 200 g/t, and the amount of foaming agent is 100 g/t, the ash content of the flotation concentrate is 43.15%, the recovery rate of organic matter is 73.18%, and the oil content is 20.77%. According to XRD, FTIR, SEM+EDS analysis, the main reason for the increase of oil content is that the relative dissociation of flotation products is improved, the organic matter components are enriched to the maximum extent, and the carbon content is increased. The molecular simulation further reflects that the selected collector and organic matter have strong bonding bonds, effectively strengthening the flotation process. The research results provide basic research support for the high-value utilization method of oil shale in West open-pit mine.

    2023 S2 v.29 [Abstract][OnlineView][Download 2046K]
  • Fineness measurement of pulverized coal based on image recognition technology

    MEI Zhenfeng;YAN Qingqi;ZHU Jinyong;JI Houzhan;ZHENG Di;GAO Zhengyang;SONG Yangfan;Suzhou TPRI Energy & Environmental Technology Co.,Ltd.;Department of Power Engineering,North China Electric Power University;

    Pulverized coal fineness is an important parameter that affects boiler combustion.The coal powder samples in 15 boiler tubes of 600 MW unit were measured by sieving method and image recognition method.The results show that the maximum absolute error to R_(90) of the image method and the screening method is-2.73%,the average relative error is 1.97%,the maximum absolute error of R_(75) is 3.80%,and the maximum relative error is 8.60%.The detailed information of particle size distribution of pulverized coal particles can be obtained by image recognition method.The results show that the particle size of C grinding coal powder is mainly distributed in 50-80 μm, and that of D and E grinding are mainly distributed in 55-100 μm and 40-80 μm.

    2023 S2 v.29 [Abstract][OnlineView][Download 2001K]
  • Research progress of asphalt modifier based on coal direct liquefaction residue

    WANG Haitao;LAI Shiyao;BI Fei;LIANG Hao;FAN Liang;Zaozhuang Yinguang New Building Materials Co.,Ltd.;Shandong Transportation Research Institute;

    The application of coal direct liquefaction residue(DCLR) in the direction of asphalt modifier was summarized, its physical properties was expanded, advantages and disadvantages of each modifier by comparing Qingchuan rock asphalt and Trinidad Lake asphalt was analyzed and the important significance of coal direct liquefaction residue as asphalt modifier in the clean and efficient utilization of coal was discussed. From the perspective of compatibility theory, the research and development of asphalt modifier were introduced from the perspective of composite modification. Finally, the future development of coal direct liquefaction residue as asphalt modifier was prospected to provide reference and reference in the design of modification system method, the understanding of material behavior mechanism and pavement functionalization.

    2023 S2 v.29 [Abstract][OnlineView][Download 1833K]
  • Removal of CO from sintering flue gas by CuO-CeO_2 catalyst supported on KMnO_4 modified activated carbon

    PANG Huaping;SHEN Zhenghua;XING Xiangdong;No.4 Senior Middle School of Puyang Oilfield;School of Metallurgical Engineering, Xi′an University of Architecture and Technology;

    CuO-CeO_2/AC-xKMn catalyst was prepared by impregnation method using KMnO_4 modified AC as support for the removal of CO in sintering flue gas. The structure and properties of the catalysts were characterized by XRD, N_2 absorption-desorption, SEM, XPS and H_2-TPR. The results showed that the modification of KMnO_4 could improve the catalytic performance of CuO-CeO_2/AC catalyst, and the CuO-CeO_2/AC-6KMn catalyst modified by 0.06 mol/L KMnO_4 exhibited the best catalytic performance, which could convert 99.5% CO at 160 ℃ for 62 h without decreasing. Modification with KMnO_4 could increase the roughness of AC surface, improve the dispersion of active particles, which prevented the aggregation and growth of metal oxides, and provided more active sites for CO oxidation. However, the high concentration of KMnO_4 will destroy the pore structure of AC, resulting in the reduction of the specific surface area of the catalyst. The surface of KMnO_4 modified catalyst had more Cu~+ active sites, which improved the adsorption capacity of CO. In addition, the concentration of Ce~(3+) on the catalyst surface, the number of lattice defects and oxygen vacancies increased, which result in the increase of mobility of lattice oxygen, and the improvement of redox performance of the catalyst.

    2023 S2 v.29 [Abstract][OnlineView][Download 2230K]
  • Optimum conversion and yield of coal direct liquefaction process

    ZHAO Pengcheng;WANG Xiwu;Ordos Coal to Oil branch,China Shenhua Coal to Oil Chemical Co.,Ltd.;

    The main process variables in direct coal liquefaction process are reactor temperature, reactor operating pressure, space velocity, etc.. The main performance characteristics of direct coal liquefaction process are coal conversion, residue conversion, gas yield and liquid yield. By analyzing the variables affecting the reaction of coal direct liquefaction process, and according to the reaction of coal direct liquefaction process at a certain reaction temperature, reaction pressure, the optimum operating conditions of coal conversion, liquid yield, gas yield and asphalt yield in direct coal liquefaction process under different operating loads were discussed, finally, the optimum operation conditions for the industrial unit of the direct coal liquefaction process were obtained. Under the same reaction temperature and pressure, the conversion of pulverized coal and the yield of liquid increase with the increase of the residence time of the material, the yield of the generated liquid in coal increases with the increase of the load, the yield of gas increases with the increase of the residence time of the material, and the yield of asphalt increases with the increase of the residence time of the material, the comprehensive energy consumption increases little with the increase of coal direct liquefaction process unit load. Under the same reaction temperature and pressure, the optimum conversion and yield of direct coal liquefaction process are 60% load(dry pulverized coal space velocity 0.22 t/(h·m~3). In the industrialized operation of coal direct liquefaction process, it is necessary to ensure a certain production capacity and economic benefits. In addition to taking into account the conversion rate and all kinds of yield as high as possible, it is also necessary to take into account the comprehensive energy consumption and the output of the target product produced in coal. Comprehensive analysis shows that under the condition of constant reaction temperature and pressure, the economic benefit is higher when the operation load of the direct coal liquefaction unit is higher(the air velocity of dry pulverized coal is above 0.3 t/(h·m~3).

    2023 S2 v.29 [Abstract][OnlineView][Download 1826K]
  • Effect of impregnation sequence of vanadium and molybdenum on the Na resistance of de-NO_x catalyst

    HUANG Li;YUE Yanwei;ZONG Yuhao;LI Jinke;GAO Yibo;WANG Hu;HAN Pei;Datang Nanjing Environmental Protection Technology Co.,Ltd.;Instrumental Analysis Center,Inner Mongolia University of Science & Technology;

    A serious of V_2O_5-MoO_3/TiO_2 de-NO_x catalysts were prepared by different impregnation sequences of vanadium and molybdenum. Subsequently, the corresponding Na poisoned catalysts were prepared. The physiochemical properties of the different catalysts were investigated in detail by means of XRF,XRD,N_2-adsorption, H_2-TPR,XPS and NH_3-TPD analyses. The catalytic performance and Na resistance of the different catalysts were studied via a fixed-bed micro-reactor. The results show that the impregnation sequence had little impact on the crystal structure and pore structure of the catalyst. In comparison with VMo/Ti catalyst prepared by co-impregnation method, the V-Mo/Ti catalyst obtained by first impregnating V and then Mo possessed higher polymeric vanadate content, O_α,and acidity. Consequently, V-Mo/Ti catalyst showed better catalytic performance. With regards to Mo-V/Ti catalyst which was prepared by first impregnating Mo, lower catalytic activity was observed because of the unbalance of its V~(5+)/(V~(3+)+V~(4+)+V~(5+)) ratio. The introduction of Na could decrease of the BET surface area, reducibility, and acidity of the catalyst, leading to the decline of the catalytic activity. For V-Mo/Ti catalyst, the MoO_x species were located on the external layer of the catalyst, which could weaken the impact of Na on the active sites of the catalyst. Consequently, the Na resistance of this catalyst was superior to that of the VMo/Ti and Mo-V/Ti catalysts.

    2023 S2 v.29 [Abstract][OnlineView][Download 1998K]
  • Effect of bamboo charcoal powder on structure and electrochemical properties of ashless coal-based activated carbon

    JI Mengting;FAN Lihua;WANG Xueyu;YU Nalin;JIANG Hongwei;College of Chemical Engineering,North China University of Science and Technology;Hebei Key Laboratory for Environment Photocatalytic and Electrocatalytic Materials;

    The activated carbons for EDLC were prepared from lignite based ashless coal and bamboo charcoal powder with KOH as an activator. The structure of the activated carbons were characterized by XRD, SEM, N_2 adsorption and FT-IR. Electrochemical properties were tested by GCD, CV and EIS. The results shows that the electrochemical performance of the activated carbon prepared by adding bamboo powder into lignite based ashless coal is improved, and the optimum addition of bamboo charcoal powder is 30%. The specific surface area reached 2 976 m~2/g, which is 59% higher than that no bamboo charcoal powder addition. The total hole volume is 1.59 cm~3/g, with a mesopore ratio of 15.6%. The specific capacitance reached 377.9 F/g, which increased 69.9% in specific capacitance. The capacitance retention is 84.34% at 5 A/g. The capacitance retention is 86.71% after 1 000 cycles, which shows perfect ratio characteristics and cycling stability.

    2023 S2 v.29 [Abstract][OnlineView][Download 2275K]
  • Application discussion of zeolite membrane dehydration technology in syngas to ethylene glycol process

    ZHENG Wei;REN Yiren;WANG Jianping;WEN Ting;ZHAO Zhenxin;MA Mingjie;School of Chemistry and Chemical Engineering, Henan Polytechnic University;School of Materials and Chemical Engineering, Henan University of Urban Construction;Hefei JiangXin Chemical Science & Technology limited company;

    In order to improve the economic value of by-products from syngas to ethylene glycol, application of zeolite membrane dehydration technology in the syngas to ethylene glycol process was discussed. For the dehydration of crude ethanol and mixed alcohol esters, the zeolite membrane dehydration process is designed respectively, the material balance and utility consumption are calculated, and the economic evaluation are analyzed. The results show that zeolite membrane dehydration can dehydrate crude ethanol to 99.5% anhydrous ethanol and increase the content of mixed alcohol ester to 99%. Membrane dehydration has the characteristics of low investment, low energy consumption and good benefit. It is necessary to accelerate the popularization and application in the syngas to ethylene glycol industry.

    2023 S2 v.29 [Abstract][OnlineView][Download 1929K]
  • Experimental study on the gasification characteristics of coal char in the context of underground coal gasification

    JIN Dehao;CHEN Shanshan;SUN Fenjin;HU Zhongfa;PENG Yangfan;ZHOU Yuegui;China-UK Low Carbon College, Shanghai Jiao Tong University;Institute of Thermal Energy Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University;Research Institute of Petroleum Exploration and Development;

    A high pressure and high temperature fixed bed coal gasification system was designed to simulate the reduction zone of underground coal gasification. An investigation on the gasification characteristics of lump coal char was conducted, and the effect of gasification pressures(0.1-4.0 MPa), temperatures(750-900 ℃) and mass ratio of H_2O/CO_2 were considered. Results show that increasing the gasification pressure promoted the increase of the CH_4 concentration in the syngas, while the concentration of the H_2 component was inhibited. The increase of the gasification temperature promoted the formation of H_2, CO and CH_4, and the concentration of each component reached the maximum value of 33.2%, 12.8%, and 1.4% at 900 ℃, respectively. When the mass ratio of gasification agent H_2O/CO_2 increased, the concentration of H_2 and CH_4 increased significantly, while the concentration of CO decreased. The H_2O/CO_2 mass ratio no longer affected the concentration of syngas components after it reached 3.0. The condition for achieving the highest heat value of syngas for Shenmu bituminous coal was determined at 1 MPa, 900 ℃ and H_2O/CO_2 mass ratio of 2∶1, which produced the syngas with a composition of 33.2% H_2, 12.8% CO, 1.4% CH_4 and LHV of 5.7 MJ/m~3.

    2023 S2 v.29 [Abstract][OnlineView][Download 2108K]
  • Analysis and characterization of coal in processing and utilization

    SHANG Ming;CHN Energy Shendong Coal Preparation Center;

    Coal is highly inhomogeneous in nature and therefore requires multiple analytical techniques to characterize it in order to accurately predict its behavior during transformation processes such as combustion, gasification or liquefaction. Conventional analyses(proximate analysis, ash analysis and ash melting temperature) assume that coal is a homogeneous material and provide only bulk properties. The performance correlations based on these analyses do not adequately describe the effect of coal quality on conversion efficiency and process sorting. Many advanced holistic analytical techniques, such as FTIR and ~(13)CNMR,provide information about the organic structure of the coal. Bulk analytical techniques, such as XRD,provide information about the mineral type in the coal. TMA provides detailed thermal behavior of ash relevant to power plant operation. Several advanced characterization techniques have emerged in recent years that treat pulverized coal as a non-homogeneous material composed of individual particles and enable more detailed detection of these coal particles. AR techniques provide variation in reflectance through a measure of heterogeneity of the organic fraction. CCSEM analysis techniques provide more detailed information about the minerals in the coal and the mineral coal assemblage in the coal dust.

    2023 S2 v.29 [Abstract][OnlineView][Download 1887K]
  • Problem analysis and countermeasures of urea hydrdysis anmoia production system

    CHEN Wentong;FAN Shuaijun;CHEN Liutong;MA Shuangchen;Shenneng Baoding Power Generation Co., Ltd.;North China Electric Power University;

    Coal power companies in various places are actively carrying out the upgrading and transformation of urea instead of liquid ammonia. Taking a power plant as an example, the actual operation case of 2×350 MW unit denitrification system using urea hydrolysis ammonia production process was summarized, and the urea hydrolysis steam system in the ammonia production system was expounded. Precautions during the operation of the urea dissolution system and the hydrolyzer, and analyzed the defects such as blockage of the ammonia supply pipeline, valve corrosion and pitting corrosion of the hydrolyzer heating coil found during the operation of the urea hydrolysis ammonia production system. The operation principle of the hydrolysis system, the corrosion mechanism of product gas condensation and the corrosion mechanism of the hydrolyzer coil and cylinder were studied and analyzed, and the corresponding optimization and solutions for the defects during system operation were given. The operating temperature can reduce the possibility of back-condensation corrosion, and the hydrolysis ammonia supply system runs stably after the modification, which greatly improves the operation safety and reliability of the urea hydrolysis system and the denitrification device. Since chloride ions are carried by urea, it is recommended to strengthen the sewage discharge of the hydrolyzer, alleviate the enrichment of chloride ions, increase the frequency of pH inspection of the heat exchanger water drainage, and ensure that leakage problems are detected and replaced in time. At the same time, the corrosion of metal equipment by chloride ion can be reduced by means of low chlorine urea or improvement of equipment and application of corrosion inhibitor. Through the analysis and disposal of the common abnormal problems in the operation of the urea hydrolysis ammonia system, it can provide an effective reference for the normal operation of similar urea hydrolysis ammonia production system.

    2023 S2 v.29 [Abstract][OnlineView][Download 1894K]
  • Reviews on separation and application of residual carbon from coal gasification slag

    QIAO Hui;ZUO Yue;QU Jie;TENG Daoguang;FAN Guixia;LI Peng;School of Chemical Engineering, Zhengzhou University;

    Coal gasification slag awful is a solid waste residue produced by coal gasification, mainly including residual carbon and inorganic minerals(SiO_2、CaO、Al_2O_3,etc). The efficient disposal and high-value utilization of coal gasification slag gain substantial social and economic significance. The residual carbon scarcely has a high carbon content, doesn′t purely have a relatively complete pore structure and a large specific surface area but also possesses a certain electrocatalytic activity. Therefore, realizing the efficient separation and high-value utilization of carbon residues in coal gasification residues is not only an encouraging response to solid waste disposal and environmental protection but also a material manifestation of the effective recovery and deep utilization of secondary resources. The development of coal gasification slag in construction, soil modification, boiler blending, and high-value-added materials is summarized, with emphasis on the separation and utilization of high-value-added residual carbon. The chemical composition and surface characteristics of residual carbon are briefly summarized. The difference in reactivity of residual carbon in coarse slag and fine slag is carefully compared, and the research progress of flotation, electrical separation, and gravity separation in the field of residual carbon separation is succinctly summarized. Compared with the research on a sole agent, process flow, and equipment in traditional flotation, the research on novel agents and combined equipment has significantly improved the selectivity of residual carbon separation. However, the problem of large dosage of flotation reagent is still the key problem for the current research. Residual carbon typically exhibits excellent properties in adsorption, electromagnetic absorption, and electrochemistry due to its unique compositional characteristics and surface properties. Therefore, the deep deashing, surface modification, and composite application of residual carbon are not only expected to improve the performance and application fields of carbon residue-based materials but also have long-term research and development and application prospects.

    2023 S2 v.29 [Abstract][OnlineView][Download 2069K]
  • Relation between volatiles yield and caking index of blending coal from coking coal

    WANG Yongwei;ZHAO Xueqing;Department of Chemistry and Chemical Engineering,Lyuliang University;

    To research the relation between volatiles yield and caking index of blending coal from coking coal, a coking coal with strong caking properties and two coals(a meager lean coal and a weakly caking coal) with poor caking properties were selected as the experimental samples to conduct the blending coal experiment. The relation between volatiles yield and caking index of blending coal has been studied through the determination of volatiles yield and caking index of different blending coals. The results show that the caking index of the blending coal increases with the increment of the blending ratio of coking coal and the curves of the caking index against the blending ratio of coking coal take on an arcuate shape. The trends of volatiles yield of the two types of blending coal from the coking coal blended with the meager lean coal or the weakly caking coal are different, and both of the changing trends of volatiles yield from the two types of blending coal are opposite. The volatiles yield of the blending coal obtained from the coking coal and the meager lean coal increases linearly with the increment of the blending ratio of coking coal. On the contrary, the changing tendency of the volatiles yield of the blending coal obtained from the coking coal and the weakly caking coal overall decreases with the increment of the blending ratio of coking coal. When the meager lean coal is mixed with the coking coal, the caking index of the blending coal nonlinearly increases with the increment of the volatiles yield of the blending coal. Whereas the caking index of the blending coal overall falls with the increment of the volatiles yield of the blending coal obtained from the weakly caking coal and the coking coal. Consequently, when the coking coal is blended with the poorly caking coal, the caking index of the blending coal is related to the volatiles yield of the blending coal, and the relation between the caking index and the volatiles yield depends on the structure and the coal quality of the coal with poor caking properties.

    2023 S2 v.29 [Abstract][OnlineView][Download 1819K]
  • Effect of physical decarbonization gasification slag on properties of cement mortar

    YU Wei;WANG Xuebin;SHANG Jingpeng;ZHANG Yufeng;SHI Zhaochen;WANG Mingjing;School of Energy and Power Engineering,Xi′an Jiaotong University;School of Chemistry and Chemical Engineering,Xi′an University of Science and Technology;BESINO Environment Ltd.,Shanghai;Zhongsheng Environmental Technology Development Co.,Ltd.;

    Coal gasification slag is a kind of solid waste with high carbon content produced in the process of coal gasification. At present, it is mainly treated by landfill, which not only occupies a lot of land, pollutes soil and water, but also causes energy waste. After physical separation of Yulin gasification slag, clean carbon, inert slag and fine tail gasification slag products can be obtained. The dry basis gross calorific value of clean carbon can reach 25.12 MJ/kg. Inert slag products include decarburized coarse tailings and decarburized fine tailings. The two tailings samples collected are mainly composed of SiO_2,Al_2O_3,CaO and Fe_2O_3,with the loss on ignition of 1.53% and 1.20% respectively. Two kinds of tailings samples were ground to prepare cement mortar with different dosage, and the strength activity index reached 75% and 79% respectively. When the cement is replaced by 15%,the flexural strength and compressive strength of the two decarburized tailings mortar are close to that of pure cement mortar. Under the condition of this content, the two decarburized tailings can replace part of cement for comprehensive utilization of building materials. Both the pure cement mortar and the mortar mixed with tailings have hydration reaction at the age of 3 days, resulting in flaky structure and needle shaped strips. At the age of 110 days, the needle shaped strips of hydration products of pure cement mortar are more dense and interlaced with each other. However, the needle shaped strips in the hydration products mixed with decarburized tailings are almost disappeared, and the particles gradually form a unified whole.

    2023 S2 v.29 [Abstract][OnlineView][Download 2241K]
  • Effect and practice of coal compaction process on improving coke compactness

    ZHU Congwen;School of Architecture and Engineering,Shandong Engineering Vocational and Technical University;

    In recent years, the blast furnace has higher and higher requirements for coke quality, and it is increasingly important to improve the cold and hot strength of coke, that is, the compactness of coke. In order to study how to improve the quality of coke, first of all, the factors affecting the quality of coke-the bulk density of blended coal were studied, and the application and disadvantages of existing methods to improve the bulk density of blended coal are discussed. The coal compaction technology, and details the role of coal compaction technology in improving coke strength were intruduced. The influence of coal compaction on coke quality is verified through comparative tests, and the best coal compaction process is determined and the actual production test scheme is designed. Through the actual production test. The combined coal transportation process, compactor layout plan and test results, environmental dust removal plan and effect were intruduced. The parameter detection and control in the production process are introduced, and the production effect is verified. Based on this, the test technology and economy are analyzed, and it was concluded that coal compaction technology has great promotion value in improving coke quality. Coal compaction technology can improve the compactness of coke and meet the needs of blast furnace production. At the same time, through the practice of middling coal compaction process in coke oven, the effect of coal compaction process on improving coke cold and hot strength is verified.

    2023 S2 v.29 [Abstract][OnlineView][Download 1821K]
  • Preparation of high performance ceramics with coal gangue

    LIU Guojie;CHN Energy Shendong Coal Preparation Center;

    Using coal gangue to prepare high-performance ceramics can significantly improve the technical level and economic benefits of coal gangue utilization.The coal gangue was crushed, pulverized, pelleted and sintered to produce ceramide, and its performance was tested. The influence of coal gangue ingredients on its water absorption and density was studied when it was calcined at 1 000 ℃ for 30 min. The results show that the water absorption rate of ceramite prepared from coal waste is 25.78%, and the density is 1.925 kg/m~3. Adding a certain amount of additives to coal gangue can produce ceramics with high performance, which provides an effective way for the high value-added application of coal gangue.

    2023 S2 v.29 [Abstract][OnlineView][Download 1891K]
  • Research progress of biomass briquette for rural heating in China

    CHEN Xingru;ZHU Yiming;HUANG Dan;LI Yidi;SHEN Jiakuo;College of Energy and Environment,Shenyang Aerospace University;

    In northern China, the climate is cold in winter, and coal as the main heating fuel seriously pollutes the environment. Under the goal of carbon peak and carbon neutrality, it is of great significance to comprehensively promote clean heating in northern China, and it is particularly important to rationally utilize biomass resources with zero carbon emissions. Aiming at the current situation of biomass briquette heating in northern villages and towns, the existing problems in the development of biomass briquette in our country were summarized, such as raw materials collection and supply, development of molding and combustion equipment, related policies and standards system, combined with related heating schemes. Suggestions were put forward in optimizing the quality of stoves and improving the utilization rate of inferior biomass raw materials. Based on the analysis and comparison of biomass fuel heating policies in different parts of the country, it is found that biomass has lower priority in new energy heating. Based on the analysis of the successful cases of biomass briquette heating in villages and towns, the heating mode is selected according to local conditions and a perfect industrial chain system is formed. The scheme of local collection by farmers, local processing by enterprises and local use in the whole area is constructed. The biomass clean heating mode is explored according to the idea of enterprise-oriented, government-promoted and affordable for residents.

    2023 S2 v.29 [Abstract][OnlineView][Download 1930K]
  • Flow distribution characteristics of vertical parallel pipe groups under subcritical pressure in coal-fired power plants

    MIAO Jianjie;LI Debo;LI Huijun;QUE Zhengbin;LIAO Weihui;YAN Chao;CHEN Zhaoli;School of Energy Power and Mechanical Engineering,North China Electric Power;Southern Power Grid Electric Power Technology Co.,Ltd.;College of New Energy,North China Electric Power University;Guangdong Honghaiwan Power Generation Co.,Ltd.;

    In order to study the mass flow distribution characteristics and pressure drop distribution of working medium in the vertical parallel tube group under subcritical pressure, a mathematical model for flow distribution and pressure drop calculation of the vertical parallel tube group under subcritical pressure was established. For a 1 000 MW supercritical boiler unit, the parallel tube group under subcritical once through working condition was subjected to relevant hydrodynamic calculation, the mass flow distribution characteristics and pressure drop of the working medium in the parallel tube group of vertical smooth tube and vertical internally threaded tube with different lengths were calculated and analyzed. The results show that under the same structure and initial working fluid parameters of the water wall tubes, the position and height of the first phase change point of each water wall tube in different length parallel tube groups are the same.The outlet working medium of the parallel tube group is steam water mixture, and the outlet working medium temperature is the same. The outlet working medium temperature of different tube lengths decreases slightly with the increase of tube length.The parallel tubes with different lengths of vertical smooth tubes have good self compensation characteristics, and the mass flow of working medium in the tube group has a positive flow compensation characteristic with the heating load.The mass distribution of working fluid in the parallel tube groups with different lengths of vertical internal thread is different. With the increase of tube length, the parallel tube groups maintain good positive flow compensation characteristics. When the tube length increases to a certain extent, the positive flow compensation characteristics in the parallel tube groups gradually weaken until they disappear, and then turn into negative flow compensation characteristics.

    2023 S2 v.29 [Abstract][OnlineView][Download 2170K]
  • Structural optimization and experimental study of low-NO_x swirl burner

    ZHENG Yangfan;LIAO Weihui;RUAN Zhilong;SU Xianqiang;YAO Bin;FANG Qingyan;MA Lun;ZHANG Cheng;MIAO Miao;Guangdong Red Bay Generation Co., Ltd;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;Dongfang Boiler Group Co., Ltd.;

    Numerical simulations and field tests of an OPCC type swirl burner before and after the retrofit were carried out on the flow, combustion and NO_x emission characteristics. The retrofit measures included improving the inner secondary air cone structure and adding the separation ring. The simulation results were in good agreement with the field test data. The performances of the burner after retrofit were significantly improved, mainly reflected in:(1) A larger central recirculation zone is formed, which is conducive to entraining high-temperature flue gas and promoting rapid ignition and flame stability, especially under flexible deep-peak load regulation operation. This is reflected in that the ignition distance is reduced from 0.21 m to 0.14 m, and the flame fullness is better.(2) The char burnout rate is extremely improved, which increased from 0.02×10~(-4) kg/s to 0.11×10~(-4) kg/s.(3) The reducing area with high CO concentration is more concentrated, which is beneficial for NO_x reduction near the burner nozzle.(4) Field test data show that the CO concentration at the boiler outlet decreased from 300×10~(-6) to 85×10~(-6), the unburned carbon in fly ash decreased from 1.97% to 0.98%, and there is only slight difference of the NO concentration at outlet.

    2023 S2 v.29 [Abstract][OnlineView][Download 2400K]
  • Numerical simulation of differential adjustment characteristics on swirl burner and over-fire air dampers in 1 000 MW coal fired unit

    MEI Zhenfeng;WANG Xiaohua;ZHU Jinyong;DING Yiwen;PENG Xiaomin;ZHAO Peng;Suzhou TPRI Energyand Environmental Technology Co.,Ltd.;Xi′an Thermal Power Research Institute Co.,Ltd.;

    Secondary air systems have complex structures and compact arrangements in opposite combustion pulverized coal boilers. It is difficult to monitor the internal and external secondary air flow rates of the burner and over-fire air accurately. Then damper adjustments operate blindly in hot state. Serious air lack issues occur generally during the combustion on both sides in furnace width direction. It is important to fully improve the intake air flow rates of the burner and over-fire air on both sides. A 1 000 MW coal-fired unit is investigated to achieve the ideal damper combination in opposite combustion boiler. Complete modeling and flow numerical simulation of secondary air system are carried out. The differential adjustment characteristics of internal and external secondary air burner dampers and over-fire air dampers are systematically and quantitatively studied. Results show that: in the initial state with burner and over-fire air dampers fully opening, the distribution characteristics of secondary air flow rate in the furnace width direction are large in the center and small on both sides, which is consistent with the air lack phenomenon on both sides in the actual operation of opposite combustion furnace; with the internal and external secondary air dampers of burner/over-fire air turned to 100%/100%,60%/50%,50%/50%,40%/40%(from side to center),the flow rate distributions of burner and over-fire air demonstrate ideal diminishing trends from side to center in the furnace width direction; compared with the uniform full opening initial state, the supply air flow rates on both sides of the furnace increase by 8.3 percent; as the initial side oxygen content is 1.80%,the side oxygen content is significantly increased by 1.15 percent after the adjustment; meanwhile, the flow rate ratio of the over-fire air to the total secondary air is slightly increased by 0.6 percent, which indicates that the graded combustion degree is nearly not affected in furnace height direction.

    2023 S2 v.29 [Abstract][OnlineView][Download 2193K]
  • Numerical simulation of combustion process of 600 MW supercritical tangentially fired boiler

    HUANG Silin;LI Debo;QUE Zhengbin;MIAO Jianjie;LIU Pengyu;National Energy Group Guangdong Electric Power Co., Ltd.;China Southern Grid Power Technology Co., Ltd.;

    Coal fired power generation will still be one of the main power generation methods in China for a long time. Therefore, it is necessary to carry out a comprehensive and in-depth study on the combustion process of power coal produced in Shenfu Dongsheng coalfield. The supercritical tangentially fired boiler burning Shenfu Dongsheng coal in a power plant is selected as the research object, and the numerical simulation is carried out by using Fluent software. The results show that the air flow makes a clockwise spiral movement in the furnace, the air flow fullness in the furnace is better, and the velocity distribution is more uniform. The overall temperature distribution is relatively stable and the combustion temperature level is reasonable, but the flame adheres to the wall in the burner area, resulting in a higher furnace wall temperature in this area. The distribution of velocity field is stable and the vertical cross section is symmetrical, but attention should be paid to controlling the tangential radius of air flow and enhancing the disturbance of burnout wind. The concentration distribution of CO and O_2 is consistent, which shows that the concentration of O_2 is lower in the area with high CO concentration. In addition, with the progress of combustion, the concentration of CO decreases gradually along the direction of furnace height; Uneven distribution of heat load on the wall, high temperature at some locations, and risk of slagging. The main mode of heat transfer in the furnace is radiation heat transfer.

    2023 S2 v.29 [Abstract][OnlineView][Download 2803K]
  • Experimental study on combustion optimization and adjustment of 600 MW supercritical hedging boiler

    WU Sheng;ZHANG Zhiqiang;YAO Li;LIU Man;China Energy Science and Technology Research Institute Co.,Ltd.;Institute of Coal Chemistry of Chinese Academy of Sciences;

    In view of the problems of fly ash, large slag with high carbon content, and over-temperature of the vertical water wall during operation of a 600 MW supercritical hedging boiler, corresponding adjustment tests were carried out.The boiler is optimized and adjusted from the aspects of pulverizing system, operating oxygen, burner adjustment, etc.,and finally it is concluded that the factors affecting the high carbon content of boiler ash and slag and the over-temperature of the water wall mainly include primary wind speed deviation, coal fineness, operation oxygen, secondary air distribution content and swirl intensity of internal secondary wind.It is suggested that the rotational speed of the dynamic separator of the coal mill should be controlled at about 130 r/min, and the opening of the secondary blades in the burner should be controlled at 50°.With the increase of operating oxygen content, the carbon content of fly ash and large slag is significantly reduced. It is recommended that the dial oxygen content be maintained at about 3.3% under 550 MW operating conditions.The research results can provide guidance for the optimal operation of the same type of units.

    2023 S2 v.29 [Abstract][OnlineView][Download 1817K]
  • Numerical study and application of steady combustion under low load for inferior coal

    WANG Dujia;YANG Zhangning;RAN Shenming;DENG Jian;LI Zhengshan;Clean Combustion and Flue Gas Purification Key Laboratory of Sichuan Province;Dongfang Boiler Group Co.,Ltd.;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University;

    Under the condition of deep peak shaving and low load operation of pulverized coal fired boilers in power plants, the input heat of coal is greatly reduced, the overall temperature in the boiler is reduced, resulting in the decline of pulverized coal combustion stability, and the boiler is prone to fire extinguishing. It is very difficult to maintain the combustion stability, and the difficulty of stable combustion will further increase if inferior coal is burned. In order to improve the stable combustion ability of the coal-fired boiler when burning low-quality coal under low load operating conditions, a more economical and efficient ultra-low load stable combustion technology is developed. The numerical simulation analysis of three low load stable combustion burner schemes of the coal-fired boiler is carried out by using FLUENT software, and the distribution of combustion temperature, oxygen content, CO, etc. in each scheme is compared and analyzed. The results show that after adopting the new type of pulverized coal burner with external separation, the combustion organization in the whole furnace is better, the combustion temperature is higher, and the furnace flame fullness is better, which can effectively enhance the ability of pulverized coal ignition and stable combustion; Increasing the primary air temperature is beneficial to low load stable combustion, under low load operating conditions, a primary air heating system can be added at the burner inlet to increase the primary air operating temperature as much as possible; using external separation technology or increasing the primary air temperature can reduce the CO concentration near the water wall of the boiler side wall, making the pulverized coal burn more fully in the main combustion area, thus improving the combustion efficiency under low load. The research results provide ideas and references for practical engineering design and operation, and have been applied in a 600 MW boiler project, and achieved good low load stable combustion effect.

    2023 S2 v.29 [Abstract][OnlineView][Download 2130K]
  • Numerical simulation of pulverized coal and sludge mixed combustion in a 630 MW supercritical direct current boiler

    HE Lu;PAN Xiaotian;ZHONG Zhaoping;YANG Yuxuan;ZHANG Shan;ZHANG Qin;WANG Yulong;SUN Liming;China Energy Longyuan Environmental Protection Co.,Ltd.;School of Energy and Environment,Southeast University;

    A 630 MW supercritical direct current(DC) boiler was simulated numerically using Fluent simulation software. The effects of sludge blending ratio, water content and boiler load on the boiler temperature field and the mass concentration of pollutants NO_x, SO_2 and CO were investigated. The results show that the overall effect on the boiler is small when the blending ratio is below 10%, the overall boiler temperature changes about 10 K, the NO_x and SO_2 emission concentration increases slightly, the fuel combustion in the furnace is adequate and the combustion process is stable. The sludge moisture content is in the range of 35%-40%, which is beneficial to the blending of municipal sludge in this pulverised coal boiler, the overall boiler temperature decreases 5-10 K, the outlet CO emission concentration is reduced compared with the raw coal combustion. When the boiler load is increased from 30% to 100%, the flue gas temperature at the outlet of each heating surface of the boiler and the concentrations of NO_x, SO_2 and CO tend to increase, and the emission concentrations of pollutants at the outlet of the boiler are all within the acceptable range under the studied boiler load, indicating that it is possible to achieve the blending of municipal sludge at the full load of this pulverised coal boiler. This indicates that municipal sludge blending can be achieved at full load.

    2023 S2 v.29 [Abstract][OnlineView][Download 2148K]
  • Kinetic analysis and synergistic effect of coal and biomass blending combustion

    LUO Rui;WANG Zhiwei;CHEN Huadong;PEI Jixing;FU Liang;MO Shi;Xi′an Thermal Power Research Institute;Haikou Power Plant of Huaneng Hainan Power Generation Co.,Ltd.;

    There are many different types of coal in China. The combustion characteristics and costs of coal used in plant vary greatly. Biomass as renewable resource can be mixed with coal to solve these problems. The typical thermo-gravimetric analysis kinetics experiment was operated based on the different types of coal and biomass blending. The reaction kinetics characteristics of pure fuel combustion and mixed combustion were discussed. The suitable dynamics models by stages were compared, and the activation energy was calculated from thermo-gravimetric curve. The impacts of blending ratio, oxygen concentration and heating rate on coal-biomass synergistic effect were studied. It is found that the three stages of the mixed combustion process can be described by the first-order chemical reaction, the third-order chemical reaction and the three-dimensional diffusion governing equation respectively. The synergistic effect of biomass and bituminous coal mixing burning is reflected in the reduction of combustion intensity and burning time delaying in the burning stage of mixed combustion. The synergistic effects of blending ratio and oxygen concentration are greater than that of heating rate.

    2023 S2 v.29 [Abstract][OnlineView][Download 2543K]
  • Reasons and countermeasures of main steam temperature deviation on 600 MW supercritical opposed firing boiler

    TANG Wen;YIN Jun;GUO Xiao;LI Songshan;NING Xinyu;DING Haoxuan;LI Bin;ZHAO Xinyi;China Power Hua Chuang (Su Zhou) Electricity Technology Research Co.,Ltd.;Huanggang Dabieshan Power Generation Co.,Ltd.;

    600 MW supercritical opposed firing boiler was explored by analyzing the operating parameters of main temperature, water wall temperature and oxygen volume. Meanwhile, oxygen and steam temperature deviations were investigated to obtain correlations, indicating that steam temperature deviations were be bound up with combustion in the furnace. In addition, milling system tests were also performed. The results reveals there are large deviation of coal concentration in the different pulverized pipes of the same mill, resulting in the deviation of the pulverized coal quantity on the A and B sides of the 6 mills reaching 10.41%. When the four main mills are running under medium and low load, the deviation can reach 16.84%,that is the main reason of steam temperature deviation.

    2023 S2 v.29 [Abstract][OnlineView][Download 2149K]
  • Numerical simulation and thermal combustion adjustment of burning 100% bituminous coal from a 330 MW boiler firing lean coal

    ZHANG Wenyi;CHENG Jian;CAO Hua;CHU Wei;ZHANG Wenzhen;ZHANG Xiaojian;LIU Ping;ZHOU Mo;QIU Delai;XING Baogang;CHN Energy Changyuan Hanchuan Power Generation Co.,Ltd.;Yantai Longyuan Power Technology Co.,Ltd.;

    Shenhua bituminous coal has been planed to replace the lean coal which is the designed coal of a 330 MW boiler. For the safety and economy of the boiler operation, distribution of the furnace temperature field, the oxygen concentration field, coking and NO_x emission in furnace were analyzed with the CFD software. The results show that the temperature field is fuller and smoother, the oxygen concentration near-wall area is relatively elevated, the peak temperature is less deacrease. NO_x emission has been greatly reduced, when burning 100% of Shenhua bituminous coal with the combustion system transformation. The thermal combustion adjustment test shows that the serious coking do not occur, the NO_x emission concentration is less than 255 mg/m~3(standard status), the unburned carbon is less than 1.40%, the oxygen concentration near-wall area is 0.90%-2.01%.

    2023 S2 v.29 [Abstract][OnlineView][Download 2245K]
  • Flow distribution characteristics of supercritical pressure vertical parallel pipe group in coal-fired power plant

    MIAO Jianjie;LI Debo;LI Huijun;QUE Zhengbin;LIAO Weihui;YAN Chao;YUAN Yanming;School of Energy Power and Mechanical Engineering,North China Electric Power;Southern Power Grid Electric Power Technology Co.,Ltd.;College of new energy,North China Electric Power University;Guangdong Honghaiwan Power Generation Co.,Ltd.;

    In order to study the characteristics of flow distribution of vertical parallel tube group under supercritical pressure, a mathematical model for hydrodynamic calculation of vertical parallel tube group under supercritical pressure was established. The pressure drop and flow distribution in the parallel tube group of vertical smooth tubes and vertical internally ribbed tubes with different mass flow rates, different lengths under supercritical pressure were calculated to determine the critical mass flow rate of the parallel tube group under a fixed tube length and the critical tube length under a fixed mass flow rate. The results show that under the same conditions, the positive flow compensation characteristic of the internally ribbed tube is weaker than that of the smooth tube. The fixed length vertical internally ribbed pipe maintains a good positive flow compensation characteristic below the critical mass flow rate(1 600 kg/(m~2·s)), and the positive flow compensation characteristic gradually weakens until it disappears and turns into a negative flow compensation characteristic beyond this value. Under the same conditions, the positive flow compensation characteristics of vertical internally ribbed pipe at low mass flow rate are better than those at high mass flow rate, and the critical pipe length corresponding to low mass flow rate is greater than that at high mass flow rate. The determination of relevant calculation results provides theoretical basis and technical support for the manufacture, installation and safe operation of boiler water wall under supercritical pressure.

    2023 S2 v.29 [Abstract][OnlineView][Download 2748K]
  • CFD simulation and optimization of flow field in front flue of electric precipitator in a 300 MW coal-fired unit

    SUN Zhipeng;Thermal Power Technology Research Institute,China Datang Corporation Science and Technology Research Institute;

    Based on computational fluid dynamics(CFD) and Fluent software, the flow characteristics of the flue field in a 300 MW coal-fired unit were numerically analyzed. The simulation results of flow velocity at flue duct monitoring points are basically consistent with the measured data. Simulated analysis show that vortex is generated in the step area at the corner of vertical flue and horizontal flue. The gas flow inertia and unreasonable design at duct corners are the main reasons for high-speed zone and enlargement of velocity non-uniformity coefficient on the outlet surfaces. By setting guide plate and rectifier plate, the velocity non-uniformity coefficients is significantly reduced, the high-speed zone is basically disappeared, and the flow difference between different inlets of the precipitator is small.

    2023 S2 v.29 [Abstract][OnlineView][Download 2464K]
  • Simultaneously on-line measurement of temperature and gaseous sodium in coal-fired furnace based on spontaneous emission analysis

    FAN Xian;REN Xuejun;GAO Guodong;WANG Dong;ZHANG Xiong;PU Yang;MA Shuai;YAO Bin;LOU Chun;Huadian Xinjiang Zhundong Wucaiwan Power Generation Co.,Ltd.;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

    The alkali metals released in the combustion process of high alkali fuels such as Zhundong coal and biomass are probable to cause fouling and slagging on heating surface of furnace and affect the operation safety. Therefore, quantitative measurement of alkali metals in combustion process is of great significance for combustion optimization. The simultaneous on-line measurement of temperature and gas phase sodium concentration in coal-fired boilers was carried out based on spontaneous emission spectrum analysis technology. First, an experimental method for measuring gas phase sodium concentration in combustion flame by using flame photometer to test FES(Flame emission spectrometry) technology was proposed, and the verification experiment of measuring gas phase Na concentration was carried out. The measured value and the actual value in the range of 0-12.2 mg/m~3 have high accuracy. Finally, an on-line measurement system for combustion temperature and gas phase sodium concentration was developed and applied to the site of large-scale thermal power plant pulverized coal boiler. The continuous online monitoring results show that the gas Na concentration and flame temperature have a positive correlation with the unit parameters and change synchronously. The maximum temperature and gas Na concentration in the measuring point area are 1 220 ℃ and 2.3 mg/m~3, respectively. Based on the on-line measurement results, it has guiding significance for the subsequent prediction of fouling and slagging on the heating surface of the furnace and the adjustment of boiler combustion.

    2023 S2 v.29 [Abstract][OnlineView][Download 2140K]
  • Influence of sludge co-combustion on the combustion stability in a 630 MW pulverized coal boiler

    CAO Wenliang;LI Xiaojin;HOU Bo;CHANG Shaoying;HE Lu;Guizhou Electric Power Co.,Ltd.,China Energy Investment Group Co.,Ltd.;Longyuan Environmental Protection Co.,Ltd.,China Energy Investment Group Co.,Ltd.;

    To understand the influence of sludge co-combustion on the combustion stability in large pulverized coal boilers, the thermogravimetric analysis(TGA) was used to compare the combustion characteristics parameters of various sludges, and the influence of sludge blending on coal combustion characteristics was quantitatively studied. Taking a 630 MW supercritical pulverized coal boiler as the research object, the temperature field distribution of the boiler with sludge co-combustion was simulated and predicted by the Fluent numerical simulation. Meanwhile, the influence of sludge co-combustion on the combustion stability of the boiler was analyzed by combining the operation of the actual furnace with engineering practice. TGA results show that co-combustion of sludge with a moisture content of 40%(dried sludge) in a ≤10% ratio improves the ignition performance, burndown performance and combustion intensity of the mixed fuel, and reduces the combustibility index, stable combustion index and comprehensive combustion characteristic index of the mixed fuel by only 2%-7%. Fluent numerical simulation results indicate that when the dried sludge co-combustion ratio is ≤10%,the outlet temperature of each heating surface is only increased by about 10 ℃,the fuel in the furnace is fully combusted, the combustion process is stable, and the temperature field distribution is not significantly influenced. With the dried sludge co-combustion ratio of 10%,when the boiler load is reduced from 100% to 30%,the outlet temperature of each heating surface is reduced, the exhaust heat loss is reduced, and the thermal efficiency of the boiler is still higher than the value under full load operation. In addition, the field test results demonstrate that the furnace temperature of the 630 MW pulverized coal boiler shows a downward trend after burning sludge, but the decline is limited.

    2023 S2 v.29 [Abstract][OnlineView][Download 2119K]
  • Analysis on characteristics and synergism of biomass and coal gangue mixed combustion

    LI Yuanyuan;SONG Changzhong;GONG Zhen;LI Ze;HAO Songtao;College of Energy and Power Engineering,Inner Mongolia University of Technology;

    In order to study the mixed combustion characteristics of biomass and coal gangue, thermogravimetric analyzer was used to conduct combustion tests on the mixed samples of corn straw and coal gangue with different mixing ratios, and the synergistic effect and dynamics analysis were carried out. The test results show that there are three distinct change stages in the whole combustion process of mixed fuel, namely, water evaporation stage, volatile analysis and combustion stage, and fixed carbon combustion stage. With the gradual increase of the mixing proportion of corn straw, the maximum weight loss rate gradually increases, the maximum weight loss temperature and the total weight loss rate gradually decrease, the ignition temperature and burn out temperature of the mixed sample decrease, the flammability index and the comprehensive combustion characteristic index increase, and the activation energy in the high temperature zone decreases gradually. However, when the mixing ratio of corn straw is greater than 2∶8, the activation energy tends to be stable gradually. When the temperature is lower than 200 ℃, the conversion rate of mixed fuel has little difference, but when the temperature is higher than 200 ℃, the conversion rate increases with the increase of corn straw content at the same temperature. At different ratios, volatilization and combustion stages are inhibited to varying degrees. In the whole combustion reaction process, when the mixing ratio of corn straw and coal gangue is 2∶8, the promotion time is the longest and the heat release in the whole combustion process is the largest.

    2023 S2 v.29 [Abstract][OnlineView][Download 1993K]
  • Experimental study on the influence of fine gasification slag blended with fuel coal on combustion characteristics

    TAO Weitong;CHEN Hong;ZHANG Xiuchang;LI Zepeng;WEI Geng;MO Chunhong;Clean Combustion and Flue Gas Purification Key Laboratory of Sichuan Province;Dongfang Boiler Co.,Ltd.;

    The resourceful utilization of fine gasification slag is a current research hotspot, fine gasification slags can obtain better combustion characteristics when blended with coal. The combustion characteristics of fine gasification slag blended with coal were analyzed. Firstly, the physical and chemical property analyses of fuel coal and fine gasification slag were carried out respectively, such as proximate analysis, ultimate analysis, calorific value and ash composition analysis. Then the combustion characteristics of fine gasification slag blended with fuel coal in different proportions(0,8.17%,25.56%,44.48%,65.15% and 100%) were studied by thermogravimetric test. Finally, the trial firing tests of 50 kW downer were carried out. The results show that the calorific value, V_(daf) and M_(ad) of two fuels are quite different, and the V_(daf) of fine gasification slag is low. The results of thermogravimetric tests show that the ignition characteristics of the blended fuel are inclined to the easily ignitable coal(fuel coal) and the burnout characteristics are inclined to the hard ignitable coal(fine gasification slag). After blending with fine gasification slag, ignition characteristics of the blended fuel are stable but burnout characteristics are poor. In the first downer test, the mixing ratios of fine gasification slag are 0%,25.56%,44.48% and 65.15%,respectively. The excess air coefficient is 1.18%,the oxygen content is 3.2%,and the burnout air rate is controlled at about 22%. It is found from the trial firing test that as the proportion of gasification slag increased, the emission of nitrogen oxides would decrease, the emission of carbon monoxide and the carbon content of fly ash would increase, and the burnout characteristics would become worse. In order to study the burnout situation after increasing the excess air coefficient, on the basis of the working condition with 65.15% fine gasification slag mixing ratios, the variable excess air coefficient tests were carried out. As the oxygen content increased from 3.2% to 3.8%,the emission of nitrogen oxides increased by 46.9% but the carbon content of fly ash decreased. When the oxygen content increases, the results of test conform to the expectation. When the proportion of fine gasification slag blended with fuel coal increases, the excess air coefficient needs to increase for operation, and the carbon content of fly ash can be maintained in an acceptable range. Based on these test results, the proportion of fine gasification slag can be adjusted to about 30%,which makes the corresponding burnout characteristic acceptable.

    2023 S2 v.29 [Abstract][OnlineView][Download 1954K]
  • Influence of biomass direct combustion coupled coal-fired boiler technical routes

    ZHOU Lingyu;CHEN Gang;YANG Gaobo;WANG Zhichao;CHENG Ruishen;SHE Yuanyuan;NIE Xin;LIU Hui;Xi′an Thermal Power Research Institute Co., Ltd.;Xi′an Yi-Tong Thermal Technology Service Co., Ltd.;

    With the goal of “30·60” carbon peak and overall being clear, further reducing the energy consumption of coal-fired power units, improving flexibility and adjustment capabilities, and promoting the efficient, clean and low-carbon transformation of the power industry are the directions of coal-fired power units in the new era. As an important utilization method, biomass direct combustion has great potential for development due to its wide raw material sources, simple technical solutions, and low equipment investment costs. Three direct-fired mixed-burning technical routes including flue gas drying +granule forming + grinding and direct blending in the original pulverizing system, primary crushing + secondary crushing + air conveying + common pipe coupling and primary crushing + secondary crushing + flue gas drying + flue gas conveying + common pipe coupling were investigated based on the supercritical coal-fired boiler. The influences before and after blending biomass were analyzed through thermal calculation. The calculation includes the drying calculation of the biomass by the flue gas, the calculation of the thermal efficiency after bypass the flue gas, the calculation of the influence of air transport on the thermal efficiency of the boiler, and the thermal calculation after the biomass ismixed.The results show that the boiler exhaust gas temperature increases, the thermal efficiencydecreases, the amount of desuperheating water increases, the power consumption rate of the plant increases, and the power supply coal consumption increases; the power supply CO_2 decreases, and with the increase of the blending ratio, the effect increase in magnitude. Direct mixing method with primary and secondary crushing with flue gas conveying has the least impact on the boiler. Under the loads of 100%, 75%, and 50%, the influences are performed with the heat proportions of 10%, 20%, 30%, and 40% respectively. The results show that after blending biomass the boiler exhaust gas temperature increase by 2.46-14.14 ℃, thermal efficiency decrease by 0.23%-1.23%, desuperheating water increase by 5.8-30.7 t/h, power supply coal consumption increase by 2.09-8.91 g/kWh, power supply CO_2 decrease by 79.19-336.44 g/kWh, a decrease of 11.1%-40%.

    2023 S2 v.29 [Abstract][OnlineView][Download 2105K]
  • Application of ash condition monitoring technology for boiler heating area based on radiation spectrum

    WANG Xin;ZHU Runru;LIU Huawei;YUAN Ye;ZHANG Yiyang;LI Gengda;HUANG Yun;CHN ENERGY New Energy Technology Research Institute Co.,Ltd.;State Key Laboratory of Multiphase Complex System,Institute of Process Engineering,Chinese Academy of Sciences;School of Energy Power and Mechanical Engineering,North China Electric Power University;Huaneng Changjiang Environment & Technology Co.,Ltd.;Institute of Nuclear and New Energy Technology,Tsinghua University;

    One of the most important parameters in boiler operation is wall temperature. In recent years, pipe explosion accidents caused by overall overtemperature or local overtemperature have occurred from time to time. The main way to improve the service life of the boiler is the accurate measurement and control of the temperature of the important high-temperature heating surface(wall temperature) of the boiler. The ash condition monitoring technology of boiler heating area based on radiation spectrumwas developed, and a corresponding monitoring system was built to overcome the RGB temperature measurement problem of fly ash composition changes caused by the change of working condition parameters. The temperature and morphology of ash deposition surface were accurately measured, which could provide reliable basis and boundary conditions for wall temperature monitoring and calculation. The results show that the temperature and thickness distribution of ash on the heating surface are nonlinear, which leads to the non-uniformity of wall temperature and other parameters, and the operation state and life of the pipeline are affected.

    2023 S2 v.29 [Abstract][OnlineView][Download 2188K]
  • Dynamic feedback characteristics of AGC variable load process of 300 MW thermal power unit

    ZHANG Qijun;FENG Fuyuan;CHEN Heng;PAN Peiyuan;XU Gang;LIU Tong;School of Energy Power and Mechanical Engineering,North China Electric Power University;

    In order to study the dynamic characteristics of AGC variable-load thermal power units, a simulation model based on Dymola modeling was established for a 300 MW unit of a northern power plant to verify the validity of its steady-state process and to derive the law of change of the main thermal parameters of the unit under different variable load rates. The economic performance of the unit under different variable load rates was also analyzed by combining the economic indexes of two rules in the power grid. The results show that with the increase of variable load rate, the fluctuation of boiler output, main steam temperature, reheat steam temperature, main steam pressure and working temperature of different equipment becomes more and more intense. The maximum deviation of the main steam temperature can reach 12 ℃ at a load shedding rate of 10.5 MW/min, and for this unit, in order to ensure the economic index of two rules, the load raising rate should not exceed 5 MW/min and the load shedding rate should not exceed 7 MW/min in general.

    2023 S2 v.29 [Abstract][OnlineView][Download 2212K]
  • Effect of scattered radiation on photovoltaic power generation system

    CHAI Jin;QIAO Jiafei;WANG Bingbing;LIANG Zhanwei;CHN Energy New Energy Technology Research Institute Co.,Ltd.;

    Lighting resources have a significant impact on component selection and power generation system. Effec of scattered radiation on photovoltaic power generation system was deeply studied in typical areas of China. The radiation mechanism of sun on photovoltaic modules was analyzed, effect of scattered radiation on optimal inclination, power generation and system efficiency of photovoltaic system were explored. Results show that the optimal inclination angle is smaller than the local latitude value, and the smaller total radiation in winter and larger the proportion of scattered radiation, the smaller the inclination angle is than the latitude value.With amount of scattered radiation increases, the power generation of the photovoltaic system decreases, the back gain of double-sided module increases, the efficiency of single-sided module system decreases, and the efficiency of double-sided module system increases. When the radiation amount is small and the scattered radiation amount is large in winter, it is recommended to select a small component inclination. When the scattered radiation accounts for a large proportion, higher power yield can be obtained using double-sided module.

    2023 S2 v.29 [Abstract][OnlineView][Download 2420K]
  • Analysis and treatment of water-wall temperature deviation of supercritical W-flame boiler

    LIU Zhongxuan;WU Zhenkun;XIE Zhiwen;China Power Hua Chuang Electricity Technology Research Co.,Ltd.;Sichuan CPI Fuxi Power Co.,Ltd.;

    Since the No. 1 boiler of Fuxi Power Generation was put into operation, the leakage of the water-wall had occurred many times.In recent years, the problems of large temperature deviation of the water-wall and coking of the furnace have further aggravated because of the actual coal type deviated from the design coal type.Through the combination of in-depth mining of historical data and on-site combustion adjustment tests, the main factors affecting the thermal deviation of W-flame Boiler, such as coal calorific value, coal mixing mode and coal mill combination, were found out, and the influence of coal calorific value on the deviation of water wall temperature of W-flame Boiler was quantified. The suitable coal calorific value is within 19.26 MJ/kg. The control strategy of the water-wall temperature deviation of W-flame boiler was formed, and the transformation of the secondary air box was carried out to improve the temperature deviation of the water wall.

    2023 S2 v.29 [Abstract][OnlineView][Download 2051K]
  • Economic analysis of peak shaving auxiliary service based on numerical simulation

    CHEN Xiaolong;LYU Shanzhi;ZHANG Haitao;GE Ming;China Energy Science and Technology Research Institute Co.,Ltd.;School of Management,Shenyang University of Technology;Department of Energy and Power Engineering,Tsinghua University;

    The large-scale and high-speed development of new energy has brought great challenges to the design, configuration and operation peak shaving of the power market. It is necessary and urgent to carry out the construction of peak shaving auxiliary service market. By promoting power generation enterprises to actively participate in market-oriented competition, a peak shaving auxiliary service system based on a reasonable incentive mechanism to promote the deep absorption of new energy should be established.In order to assist in the economic calculation of peak shaving under different conditions, combined with a 600 MW supercritical coal-fired unit, the economy of peak shaving of thermal power unit was studied. By establishing the calculation model of thermal characteristics of thermal power unit, the heating capacity and peak shaving capacity of the unit during medium and low pressure bypass heating were calculated. Based on the established mathematical model of peak shaving auxiliary economic benefits, the peak shaving income characteristics of the unit were calculated and analyzed when the bypass system participates in heating, the peak shaving income difference between the heating unit and the pure condensing unit was compared, and the fluctuation interval diagram of peak shaving income and the trend curve of coal price affecting peak shaving income in various cases were drawed. The results show that there is a certain fluctuation range of peak shaving return. The benefits of thermal power units participating in peak shaving auxiliary services are affected by many factors. The peak shaving auxiliary service income of units with different periods and design conditions is different, but the overall income change trend is the same. The economic benefits of cogeneration units participating in power grid peak shaving are higher. The mathematical model of peak shaving auxiliary economic benefit proposed in this study can more accurately assist the calculation of peak shaving economy under different conditions.

    2023 S2 v.29 [Abstract][OnlineView][Download 2154K]
  • Quantitative characterization of white plume

    BI Jingwei;ZHANG Hao;YANG Lianhong;TANG Jiyun;CUI Lin;DONG Yong;National Engineering Laboratory for Reducing Emissions from Coal Combustion, Shandong University;Edwards Technologies Vacuum Engineering (Qingdao) Co.,Ltd;Department of Physics, Changji University;

    The white plume formed by the direct emission of saturated wet flue gas after wet desulfurization not only causes visual pollution, but also promotes the formation of secondary aerosols and haze. The generation and control mechanisms of white plume have been studied extensively by previous authors, but the characterization of white plume features lacks the means to describe quantitatively. In order to quantitatively characterize the white plume with different visual effects and to study the distribution pattern of droplets in it, a simulated wet smoke emission test system was built in this paper, and the shading degree was used to characterize the white plume, and the change of shading degree and droplet growth pattern of white plume diffusion under different meteorological conditions and smoke states were measured by laser particle size meter. The shading degree is the ratio of the shading cross section of the particles in the beam to the total area of the beam. The greater the shading degree, the stronger the visual shading effect of the white plume. The dimensionless relative height is defined as the ratio of the height of the white plume to the diameter of the smoke vent; the droplet average particle size is the particle size weighted by the volume fraction of different droplet sizes; the maximum shading degree and the maximum average particle size are used to characterize the white plume, which are the maximum values of the shading degree and the droplet average particle size during the diffusion of the white plume, respectively. Firstly, the variation of shading degree and droplet size along the vertical and horizontal directions of the white plume under different environmental conditions with the saturated wet flue gas at 50 ℃ were studied, and analyzed the effects of ambient temperature and moisture content on the shading degree and droplet size were studied. The results showed that the shading degree and the average droplet size showed a peak shape of increasing and then decreasing along the vertical direction of the white plume. At any relative height, the droplets of each size were normally distributed by volume fraction. Along the horizontal direction of the white plume, the shading degree tended to decrease from the center to the edge, and the average droplet size was almost unchanged. The decrease of ambient temperature and the increase of ambient moisture content increase the maximum shading degree and the average droplet size of the white plume. At 4.8 g/kg of ambient moisture content, the maximum shading of white plume increased from 7.4% to 31.9% and the average droplet size increased from 9.9 μm to 26.3 μm as the ambient temperature decreased from 22 ℃ to 10.9 ℃. At an ambient temperature of 8.5 ℃, the maximum shading degree of the white plume increased from 16.89% to 42.50% and the maximum average particle size of the droplets increased slightly from 21.29 μm to 23.47 μm as the ambient moisture content increased from 1.75 g/kg to 4.21 g/kg. Secondly, the effect of the initial temperature of saturated wet flue gas on the shading degree and the average particle size of droplets was investigated. The results showed that the decrease of the initial temperature of saturated wet flue gas significantly reduced the shading degree and particle size of the white plume. Under the conditions of Jinan winter atmosphere with temperature of 7 ℃ and relative humidity of 55%, as the initial temperature of saturated wet flue gas was reduced from 60 ℃ to 40 ℃, the maximum shading degree was reduced from 39% to 19%, and the visual effect of white plume was significantly eliminated. The research results of this paper provide a means for quantitative characterization of white plume, thus laying a theoretical foundation for the development and application of whitening technology.

    2023 S2 v.29 [Abstract][OnlineView][Download 1984K]
  • Overview of energy and power system development and the flexibility retrofit of thermal power units in China

    LIU Yun;Datang Fuping Thermal Power Co.,Ltd.;

    China is highly dependent on foreign energy, and there are risks to national energy security. In order to solve energy security and cope with climate change, China has made a "double carbon" commitment internationally. To achieve this commitment, the path is the clean transformation development of the energy structure, and the major development direction is to vigorously develop wind power and photovoltaic resources. It is estimated that from 2035 to 2040,the amount of wind power and photovoltaic generation will exceed coal power. Due to the volatility and intermittency of wind power and photovoltaic power generation, large-scale access to the power system requires flexibility resources to support and consumption. China now has a large number of coal-fired thermal power units, after flexible retrofit, these peak load regulation resources are suitable for China′s national conditions. Deep peak load regulation of thermal power units is faced with low load stable combustion, hydrodynamic safety, heating surface over temperature, thermoelectric decoupling, thermal stress and low economy of units, etc. It is necessary to prevent serious safety accidents caused by deep peak load regulation. It is necessary to grasp the balance between energy transformation and energy security, and steadily promote the transformation of coal power from the main power source to the regulated power source. As for the rules of the power industry, market-oriented mechanisms should be used to solve problems, and the market-oriented reform of the power industry should be deepened.

    2023 S2 v.29 [Abstract][OnlineView][Download 2056K]
  • Thermodynamics performance of combined cycle system based on SOFC-GT-SCO_2 RBC

    GUO Yao;PANG Hong;WANG Lei;HE Yao;WANG Lina;WANG Yujie;WANG Fu;China Coal Society;Lu′an Chemical Group Co.,Ltd.;Faculty of Maritime and Transportation,Ningbo University;

    As a third-generation fuel cell, solid oxide fuel cell(SOFC) has the advantages of low cost, all-solid state, high efficiency, high power density, diversity of fuel options, and distributed power generation. The high-grade waste heat in the exhaust gascan be recovered by combining a variety of equipment, which can greatly improve the energy utilization efficiency. A combined cycle system integrating solid oxide fuel cell, Gas Turbine(GT) and Supercritical Carbon Dioxide Recompression Brayton Cycle(SCO_2RBC) was proposed, where the high-grade waste heat and residual fuel from the SOFC was utilized and transformed into power. By establishing the mathematical model of each component, the system was thermodynamically analyzed by using Matlab software, and the influence of some important parameters on the thermodynamic performance of the combined cycle system was conducted. The research results show that when the SOFC operates at 1 073 K,0.5 MPa and the fuel flow rate is 0.158 mol/s, the power generation efficiencies of SOFC,SOFC-GT and SCO_2RBC reach 55.36%,70.95% and 40.76%,respectively. A net efficiency of 74.76% can be achieved by the combined cycle, that is the introduction of the SCO_2RBC bottom cycle can increase the net efficiency of the system by about 4%. Meanwhile, the parametric analysis shows that the efficiency of the combined cycle system increases with the increase of SOFC operating temperature and operating pressure, and reduces with the increase of fuel flow rate and fuel utilization ratio.

    2023 S2 v.29 [Abstract][OnlineView][Download 2047K]
  • Response characteristics of steady-state heat and mass exchange effects in direct-contact flue gas heating system

    WU Wenjing;ZHANG Nan;YOU Shanshan;BAO Weiwei;ZHOU Yong;SPIC Power Plant Operation Technology (Beijing) Co.,Ltd.;

    Aiming at the steady-state calculation of heat and mass exchange in direct-contact flue gas heating system, the steady-state calculation model and method were established based on the four-section model, and three steady-state evaluation indexes of outlet water temperature, total water carried and effective heat transfer were selected. Compared with the field test results, the simulation error of outlet water temperature is within ±0.90 ℃, the relative error is within ±5%, and the simulation error of total water flow is within ±0.40 m~3/h. The simulation results are reliable. Based on the model and method, 121 groups of simulated working conditions were established, and the relationship between the steady-state effect of heat-mass exchange and the inlet flue gas flow, flue gas temperature, flue gas pressure, flue gas water content, inlet wastewater flow rate and the temperature difference of waste water heat transfer was quantitatively analyzed. The results show that the outlet water temperature is linearly positively correlated with the inlet gas temperature, gas pressure and water content, and negatively correlated with the heat transfer temperature difference of wastewater. It is sensitive to the inlet gas temperature and water content, but not sensitive to the flue gas flow and wastewater circulation flow. The total amount of water carried is linearly positive correlated with inlet flue gas flow and temperature, and negatively correlated with flue gas water content and waste water heat transfer temperature difference. It is more sensitive to flue gas temperature change, but has no significant relationship with flue gas pressure and inlet wastewater flow rate. The effective heat transfer is positively correlated with the circulating flow rate of waste water and the temperature difference of waste water heat transfer, but negatively correlated with the flow rate and temperature of flue gas, and is not sensitive to the change of flue gas pressure and water content. Compared with the flue gas flow, the outlet temperature is more dependent on the inlet flue gas temperature. The total amount of water also depends on the inlet flue gas flow rate and flue gas temperature. When the flue gas flow rate is low, the effect of flue gas flow rate increases, and when the flue gas temperature is low, the effect of flue gas temperature increases. The fluctuation of inlet flue gas moisture content and pressure has negligible influence on the total water intake, but the influence on outlet water temperature should be considered and corrected. For typical primary flue gas with a temperature of 85-140 ℃ and a water content of 9%-18%, when the gas-water ratio is 2 400 m~3/m~3(standard status), the temperature difference of waste water heat transfer can be controlled above 3.5 ℃, and the system has the possibility of flue gas water collection.

    2023 S2 v.29 [Abstract][OnlineView][Download 2317K]
  • Calculation method research of power supply coal consumption of back pressure heating unit

    CHEN Peng;LI Jianfeng;HAN Qin;LIU Jiuzhou;LENG Jie;CONG Richeng;SONG Jinli;State Grid Energy Hami Coal and Electricity Co.,Ltd.Huayuan Power Plant;China Electricity Council;Huadian Electric Power Research Institute;Electric Power Research Institute of State Grid Liaoning Electric Power Co.,Ltd.;

    In order to better evaluate the energy efficiency level of back-pressure or back-extraction coal-fired heating units, this paper establishes a coal consumption conversion method for back-pressure or back-extraction coal-fired heating units based on the super position principle. Or the high back pressure exhaust steam of the steam turbine does not supply heat, but continues to expand and do work in the steam turbine, then the steam turbine unit will generate more electricity, and the sum of the virtual electricity and the actual electricity generation will be used as the benchmark to calculate the coal consumption of power generation and power supply of the unit. The method is verified by taking 3 different types of coal-fired generating units as examples. The results show that the difference between the converted coal consumption and the coal consumption in pure condensing state is not more than 2 g/kWh, and the relative error is insufficient. Therefore, this method can truly reflect the actual energy efficiency level of the unit, and can be used to evaluate the energy efficiency level of the back-pressure or back-pulling unit.

    2023 S2 v.29 [Abstract][OnlineView][Download 1907K]
  • Deep utilization technology of flue gas residual heat for a 1000 MW double-reheat unit

    LI Shuai;LI Guipeng;LU Xizhen;Datang Dongying Power Generation Co.,Ltd.;Datang Northeast Electric Power Test & Research Institute Co.,Ltd.;

    Flue gas residual heat utilization is an important measure to improve the power generation efficiency of coal-fired units. The traditional residual heat utilization method is to arrange the heating surface after the air preheater, which can only recover the low-grade heat with low efficiency. For the engineering practice of a 1 000 MW double-reheat unit, three feasible deep utilization schemes of residual heat were proposed, namely, scheme 1(two-stage flue gas cooler + cold air heater),scheme 2(air preheater bypass + two-stage flue gas cooler + cold air heater),and scheme 3(air preheater bypass + hot primary air temperature adjustment+ two-stage flue gas cooler + cold air heater). In order to objectively evaluate the actual effects of different schemes, the thermal characteristic calculation model of the four-part rotary air preheater was established by finite difference method, and then the influence of the inlet air temperature and the share of bypass flue gas on the thermal efficiency of the boiler were studied.The equivalent enthalpy reduction method was used to establish a model of the thermal characteristics of steam turbines, and the influence of different heat distribution methods on the heat consumption rate of steam turbines was studied. On the basis of above, a unified economic evaluation strategy for flue gas waste heat utilization was established. On the basis of above, a unified economic evaluation strategy for flue gas waste heat utilization was established. Through the study of the system characteristics of three waste heat utilization schemes,the following conclusions are drawn.Scheme 1 can effectively reduce the heat consumption rate of the steam engine while improving the thermal efficiency of the boiler,which is more suitable for the boiler with a large difference in the hot end of the air preheater,considering the actual engineering practice,the maximum value of the scheme to reduce the coal consumption of the power supply is 1.70 g/kWh.Scheme 2 can further reduce the coal consumption of the unit,when the share of bypass flue gas is higher than 6%,the boiler efficiency will inevitably decrease,but the coal consumption of the unit power supply decreases with the increase of the share of the bypass flue gas,and the maximum value of the scheme to reduce the coal consumption of the power supply is 3.03 g/kWh.Scheme 3 can further reduce the coal consumption of the unit,which is suitable for the cooling output of the milling system boiler with a certain margin,considering the technical economy. The optimal bypass flue gas share of this scheme is 12%,and the corresponding unit power supply coal consumption reduction value is about 3.23 g/kWh. Taken together,scheme 3 is recommended for the unit. Comprehensive comparison,scheme 3 is recommended for the unit.

    2023 S2 v.29 [Abstract][OnlineView][Download 2181K]
  • Comprehensive performance of three-dimensional spiral curved tube based on erosion rate

    MO Xun;ZHANG Lifang;LIU Shijie;LI Xiuzhen;TAN Lianyuan;Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences;Key Laboratory of Renewable Energy, Chinese Academy of Sciences;Guangdong Key Laboratory of New and Renewable Energy Research and Development;Daye Sreal Heat Exchanger Co.,Ltd;Institute of Building Energy and Thermal Science, Henan University of Science and Technology;Foshan Bulu Energy Saving Technology Co., Ltd;

    The three-dimensional spiral curved tube has a fluid dynamic shape and excellent heat transfer performance, which can effectively reduce the serious erosion damage caused by coal-fired boiler flue gas. In order to study its comprehensive performance and erosion based on erosion rate corrosion model, analyze and study the erosion performance and heat transfer performance of three-dimensional spiral curved tubes with different structural parameters, and obtain reasonable shape structure parameters and operating parameters according to their comprehensive performance factors, which provides a theoretical basis for the optimal design and application of three-dimensional spiral curved tube heat exchanger.

    2023 S2 v.29 [Abstract][OnlineView][Download 2896K]
  • Standard methods of boiler thermodynamic calculation

    SHI Shuyu;FU Chunlei;SUI Haitao;LIANG Shichuan;Yantai Longyuan Power Technology Co., Ltd.;

    During the 14th Five-Year Plan period, the energy structure will be optimized persistently, the transformation and upgrading of thermal power units is of great significance to promote carbon peak and carbon neutralization. Boiler performance calculation is a necessary means and boiler thermal calculation is the top priority. In the actual project, the boiler thermal check method is used to model the boiler. According to the actual indicators of the boiler and the structural dimensions of each heating surface, the indicators of each component of the boiler during operation are calculated as the basis for troubleshooting and reconstruction.China does not have its own thermal calculation standards for power plant boiler industry. At present, the published thermal calculation standards for boilers include the former Soviet Union′s 1957 version, 1973 version and Russia′s 1998 version. Based on a large number of studies on the former Soviet Union Thermal Power Computation Standard(1973) and Russia Thermal Power Computation Standard(1998), nine main parameters were analyzed and compared, including the thickness of furnace effective radiation layer, furnace coefficient M, furnace outlet flue gas temperature, and heat transfer coefficient of convection heating surface. Combined with the data of three different power plant boiler unit: 1 000 MW ultra supercritical tower boiler, 660 MW ultra supercritical Π boiler, 300 MW subcritical Π boiler, the boiler efficiency, flue gas temperature, fuel consumption, desuperheating water volume, furnace outlet flue gas temperature, heat load and other parameters were calculated and compared with the operating parameters of the power plant. The reliability of the Russia Thermal Power Computation Standard(1998) for large pulverized coal boiler units were verified so as to provide a reliable reference for the analysis tools required for the flexibility transformation of the units.

    2023 S2 v.29 [Abstract][OnlineView][Download 2034K]
  • Analysis of thermodynamic calculation method and application of new type fluidized bed boiler burning Zhundong coal

    WANG Shihai;MA Jianfei;LU Jiayi;XU Meng;ZHAO Wenbo;LIU Kunpeng;WANG Jianjiang;WEI Bo;School of Chemical Engineering and Technology,Xinjiang University;Xinjiang Xinye Energy and Chemical Co.,Ltd.;Dongfang Boiler Group Co.,Ltd.;

    Zhundong coal, due to its high sodium character, has brought about serious fouling and slagging problems in the combustion process, limiting its widespread use. Referring to the existing thermodynamic calculation method of the circulating fluidized bed boiler, the thermodynamic calculation of the new type of fluidized bed boiler burning Zhundong coal was carried out to verify the operating parameters of the boiler under different loads. Results show that a thermodynamic calculation method for 325 t/h circulating fluidized bed boiler in a chemical plant is established by optimizing thermodynamic calculation parameters, including heat balance calculation and material balance calculation of furnace and separator, the calculated flue gas temperature and working medium temperature at the inlet and outlet of the furnace and heating surfaces at all levels are basically consistent with the measured values. The corresponding parameters of actual operation can be calculated through the variable load or coal of the boiler, which can provide data reference for the boiler operation. The difference between the measured value and the theoretical value of the new type circulating fluidized bed boiler burning Zhundong coal was analyzed.

    2023 S2 v.29 [Abstract][OnlineView][Download 1938K]
  • Experimental research and application for SCR accurate ammonia injection control

    JIN Lipeng;HE Jinliang;FANG Zhaojun;WEI Zhenzu;SONG Yubao;Suzhou Branch,Xi'an Thermal Power Research Institute Co., Ltd.;

    Aiming at the problems of excessive ammonia escape and ABS blocking in air preheater under ultra-low NO_x emission control, the CEMS multi-point rapid sampling system is designed, the SCR ammonia control logic is optimized by using the preset control model, and the experimental research and application are carried out on a 1 000 MW unit. The test results show that the CEMS multi-point rapid sampling system effectively improves the representativeness and timeliness of NO_x measurement. The NO_x measurement improves the rapidity and accuracy of automatic control of ammonia injection, and reduces the fluctuation range of NO_x emission concentration, and realizes accurate ammonia injection control with logic optimization, which can reduce ammonia escape from the source and reduce ABS blocking in air preheater.

    2023 S2 v.29 [Abstract][OnlineView][Download 2218K]
  • Discussion on design optimization measures and equipments selection of denitration system on deep peaking technology

    SHANG Tong;ZHU Canghai;ZHU Jianhong;LI Zan;LUO Zhi;LI Shuhong;DONG Chen;PAN Dong;YANG Xiaogang;YUAN Zhuang;Xi′an Thermal Power Research Institute Co.,Ltd.;Hebei Han feng Power Co.,Ltd.;Ya Xi Power Co.,Ltd.;

    In order to enhance the consumption capacity of renewable energy and implement the policy of environmental development, carrying out the transformation of flexibility and deep peaking on coal-fired power plants has became a trend in the future. Among all the environmental protections, denitration system is the most difficult to control. In this study, different design optimization measures and equipments selection from the point of technology, auto-control and the gas temperature improvements are discussed firstly, including flow field, ammonia and air mixing system, CEMS system, the gas bypass and so on. which is able to provide ideas for power plants.

    2023 S2 v.29 [Abstract][OnlineView][Download 1936K]
  • Effect of asphalt on activated coke strength and desulfurization and denitrification performance

    LIU Zihao;SHAO Yan;YANG Zhen;WANG Yuan;XIANG Hao;WISDRI City Environment Protection Engineering Co.,Ltd.;

    To explore the effect of asphalt on the performance of desulfurization and denitrification activated coke, the strength, the desulfurization and denitrification performance of the prepared activated coke were studied by changing the mixing method and content of asphalt. The results show that, due to the change of fluidity after adding asphalt to tar, compared with the active coke prepared by the mixture of asphalt and raw coal, the abrasive resistance of the active coke prepared by the mixture of asphalt and tar decreased by 1%,the compressive strength decreased by 15 N,the iodine adsorption value decreased by 74 mg/g, the desulfurization value increased by 3.6 mg/g, and the denitrification value increased by 2%. When asphalt was mixed by coal tar, increased asphalt content from 0 to 12%,we found that the abrasive resistance was increased from 92.0% to 97.7%,activated coke crushing strength increased from 280 N to 480 N,and the minimum valuei odine adsorption value was 436 mg/g while 8% asphalt. Meanwhile, the desulfurization value decreased from 38 mg/g to 20.6 mg/g, and he denitrification rate was reduced from 72% to 68%. The increase of asphalt content improved the cohesiveness between raw materials, and excessive asphalt also blocked the pores of the activated coke, causing the activated coke to harden, and reducing the desulfurization and denitrification performance.

    2023 S2 v.29 [Abstract][OnlineView][Download 1974K]
  • Mixing optimization of flue gas and ammonia gas for SCR denitrification in gas turbine unit

    SHI Lei;CHN Energy Guangxi Electric Power Co.,Ltd.;

    In order to solve the problem of insufficient mixing of flue gas and ammonia gas caused by the structure of direct injection ammonia grille in gas unit, a square mixing device based on vortex occurrence and conveying effect was developed, and it is also compared with other type mixing devices. The influence of the flow field and molar distribution of ammonia nitrogen is studied. The results show that the coefficient of variation(δ_(CV)) of ammonia nitrogen molar ratio distribution without mixer, adding disk mixer and adding square mixer is 11.9%, 10.8% and 8.95% respectively. After setting the square mixer between the high-pressure evaporator and the catalyst, the δ_(CV) value of the ammonia nitrogen molar ratio of the cross section between square mixer and catalyst is reduced to 1.20%. After setting the square mixer between the high pressure evaporator and the catalyst of the gas unit, the δ_(CV) value of the ammonia nitrogen molar ratio distribution of the cross section between the square mixer and the catalyst is decreased from 14.68% without the mixer to 3.71%. It is achieved the sufficient mixing of flue gas and ammonia gas, and created preferential conditions for the efficient catalytic reaction of the SCR catalyst.

    2023 S2 v.29 [Abstract][OnlineView][Download 2675K]
  • Application of machine learning algorithms in intelligent operation of desulfurization systems

    KONG Ruoqi;CUI Lin;DONG Yong;National Engineering Laboratory for Reducing Emissions from Coal Combustion,Shandong University;

    With the rapid development of artificial intelligence and big data, intelligent systems with machine learning and industrial big data as the core have become the mainstream trend in the development of power generation enterprises. By establishing the data model of desulfurization system, combining the self-learning and self-adaptive characteristics of machine learning algorithm, and realizing self-diagnosis, early warning and online optimization of desulfurization system with the function of system characteristic data collection and uploading, it helps to improve the intelligence level of power plants and achieve the dual goals of ultra-low emission and low-carbon operation. In the FGD system data model, the selection of core algorithms will directly affect the accuracy of parameter prediction and subsequent optimization. The basic principles of mainstream machine learning algorithms such as support vector machines were introduced, integrated learning algorithms neural network methods and the application of different algorithms in the intelligent operation of FGD systems were reviewed, and the advantages and disadvantages of different algorithms in realizing the prediction of key parameters of FGD systems and the FGD system was compared and analyzed.The advantages and disadvantages of different algorithms in achieving the prediction of key parameters of FGD system and the method of FGD system intelligent operation and optimization were compared and analyzed. Based on this, a more accurate prediction model and optimization technology route for the intelligent operation of FGD system is established, which provides a reference for the realization of low carbon and energy-saving operation under the condition of ultra-low emission of wet FGD.

    2023 S2 v.29 [Abstract][OnlineView][Download 2009K]
  • Experimental study on removal of SO_3 from coal flue gas in furnace by alkaline adsorbents

    LI Qiubai;HUANG Yaji;XU Yueyang;WANG Sheng;LI Yuxin;LI Jinlei;WEI Zekun;State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control;School of Energy and Environment,Southeast University;

    Due to blue smoke, acid deposition and building corrosion, the control of SO_3 emission has become a hot issue during the coal burning. The removal characteristics of SO_3 by common alkaline adsorbents were studied on a U-shaped quartz tube in the range of 260-380 ℃. The experimental results show that Mg(OH)_2 has the largest specific surface area and pore volume, and its removal performance of SO_3 was better than that of NaHCO_3,Ca(OH)_2,and Na_2CO_3. The SO_3 dynamic removal efficiency of the adsorbent will be improved with the increase of temperature in the early stage of SO_3 removal, and the removal rate of Mg(OH)_2 was even up to 84% at 380 ℃ in the first 10 min. When the adsorption of SO_3 tended to saturation, the increase of temperature has no obvious effect on the dynamic removal efficiency of SO_3 by used sorbents. The kinetics analysis showed that the early reaction of SO_3 adsorption by Na_2CO_3(0-40 min) conformed to the reaction-controlled shrinking core model, which is mainly dominated by the chemical reaction on the surface of Na_2CO_3. Besides, the internal diffusion-controlled shrinking core model could only describe the removal of SO_3 for the first 40 min only at 260 ℃. In the latter stage of adsorption(50-100 min),the surface reaction and interfacial diffusion can both describe the adsorption process, which means the internal diffusion of SO_3 and its chemical reaction on the surface of Na_2CO_3 jointly dominate the SO_3 removal reaction.

    2023 S2 v.29 [Abstract][OnlineView][Download 2038K]
  • Research status and prospect of mercury control technology from flue gas

    ZHAO Xinyi;LI Bin;NING Xinyu;DING Haoxuan;LIU Zhongxuan;TANG Wen;HE Ping;WU Jiang;China Power Hua Chuang Electricity Technology Research Company LTD;College of Energy and Mechanical Engineering,Shanghai University of Electric Power;

    Since China issued ultra-low emission standards, the emission standards of coal-fired power plants have become increasingly stringent. It was reported that 19% of atmospheric mercury emissions came from coal-fired power plants, with 33% from boilers, revealed by the China Council for International Cooperation on Environment and Development. Mercury, as a trace element, exists widely in nature, which possesses toxicity and atmospheric migration. In 2013,the United Nations Environment Programme promulgated the Minamata Convention, which aimed to reduce the damage caused by mercury to the environment and human health. Since the toxicity and bioaccumulation of mercury can cause irreversible damage to the human body, the realization of mercury purification in power plants has also received increasing attention. The current domestic and foreign emission standards were compared, it pointed out that the demand for mercury purification in power station boilers is becoming stronger and stronger. The causes, form transformation and measurement methods of mercury in coal-fired power plants were introduced briefly. The synergistic mercury removal technology and the activated carbon injection technology, which were relatively mature, were introduced in detail. In addition, removal effect and application prospect were described. Some new mercury capture and purification methods(adsorbent and photocatalytic mercury removal technology) were also described, which was pointed out the development trend of new mercury removal agents. Finally, some prospect were put forward, which based on the problems existing in the mercury removal, so as to realize the zero mercury emission of power station boilers as soon as possible.

    2023 S2 v.29 [Abstract][OnlineView][Download 2002K]
  • Design of flue gas bypass evaporation spray gun and system operation optimization for treating desulfurization concentrated wastewater

    GAO Honglong;YANG Wensheng;WANG Fei;LIU Huijun;GAO Lei;LIU Junjie;Shanxi Huarentong Electric Power Technology Co., Ltd.;Shanxi University, State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste Resources;

    The flue gas bypass evaporation system is more and more widely used in the zero discharge of desulfurization wastewater. However, due to the high salt content, strong corrosivity and high hardness of the concentrated filtrate of desulfurization wastewater, the nozzle of the spray gun is easy to be blocked during the bypass evaporation process. The size parameters of the spray gun were determined through experiments, which solved the problem that the filtrate blocked the nozzle of the spray gun. According to the spray characteristics of the spray gun, the evaporator size was determined and the bypass evaporation system was designed. The actual operation on site found that the amount of high-temperature flue gas is about 1.06-1.20 times of the theoretical calculation. The temperature measurement system on the evaporator can be used to judge the effect of filtrate atomization and evaporation and the blockage of the evaporator. When ash deposition occurs, start the rapping ash removal and soot blowing systems. After the evaporator system is put into operation, the flue gas temperature at the inlet of the precipitator increases by 3.6 ℃ on average, which has no impact on the dedusting efficiency of the precipitator.

    2023 S2 v.29 [Abstract][OnlineView][Download 1920K]
  • Application status of mine water treatment technology with high salinity

    LIU Zunyi;LI Xiaoliang;Xinjiang Energy Co.,Ltd.,CHN Energy;Beijing Research Institute of Coal Chemistry,CCTEG China Coal Research Institute;National Energy Technology and Equipment Laboratory of Coal Utilization and Emission Control;Beijing Key Laboratory of Coal Based Carbon Materials;

    The application treatment technology in mine water of high mineralized in China was summarized. The reuse ways of high salinity mine water and the treatment technology and water quality requirements were analyzed. The key process units of high salinity mine water treatment were analyzed from the aspects of technology characteristics, adaptability and treatment effect. The coagulation sedimentation and filtration technology of conventional treatment process, electrodialysis and reverse osmosis technology of advanced treatment process, concentration and crystallization technology of zero discharge treatment were introduced. The results show that the conventional treatment and advanced treatment technology has been relatively mature and widely used in the treatment of high salinity mine water. Although the concentration and crystallization process has a certain engineering practice, due to the constraints of investment and operation cost, there are few zero discharge engineering cases of high salinity mine water. Therefore, in the future, in the practice of zero discharge engineering of high salinity mine water, the appropriate zero discharge process should be selected according to the requirements of mine water quality and salt crystallization resource utilization.

    2023 S2 v.29 [Abstract][OnlineView][Download 1853K]
  • Experiment and numerical simulation of gas-liquid flow in Venturi jet for the decarbonization of power plant flue gas

    AN Xiaochao;BAI Yuxin;XIE Xiaozhe;YU Gengzhi;College of New Materials and Chemical Engineering,Beijing Institute of Petrochemical Technology;Beijing Key Laboratory of Fuels Cleaning and Advanced Catalytic Emission Reduction Technology;

    The Venturi jet is the key reactor for the ammonia decarbonization of the power plant flue gas. A lab scale Venturi jet was designed and manufactured. For the water-air system, the gas suction flow rate and the pressure drop under different liquid flow conditions were measured as a comparison for the numerical simulation results. The Euler Multiphase Flow Model and the Standard k-ε Turbulence Model were used to numerically simulate the internal flow field of the Venturi gas-liquid jet. After the grid independence test, the model used can better predict the experimental results, among which the deviation for the gas suction flow rate is 0.96%, and the maximum deviation of the pressure drop value is 1.26%.The numerical simulation results show that the negative pressure area of the Venturi jet mainly occurs at the front of the throat and the diffusion section. An obvious gas-liquid separation existed in the diffusion section of the Venturi jet. The streamline and turbulent kinetic energy show that there is an annular vortex region near the wall of the diffusion section, and the velocity gradient in the vortex region is large.

    2023 S2 v.29 [Abstract][OnlineView][Download 2279K]
  • Transformation and engineering design of liquid ammonia to urea in coal-fired power plant

    WANG Shuai;CHENG Xinxing;TANG Ruyi;ZHANG Chao;TIAN Lu;SHEN Shifei;LI Huanping;Xi′an Boiler & Environmental Protection Engineering Co., Ltd.;

    With the development of China′s industry and the acceleration of the urbanization process, in recent years, China′s hazardous chemical safety accidents occur frequently, the National Energy Department requires strict control of major sources of danger, especially the control of flammable and explosive gases such as liquid ammonia, hydrogen and chlorine, so accelerate the alternative conversion of liquid ammonia and urea to prevent the occurrence of major safety accidents and effectively protect the safety of people′s lives and property. The flue gas generated by the operation of thermal power plants needs to be treated by denitrification treatment to reduce NO_xto N_2 and discharged into the atmosphere. During the operation of thermal power plants, liquid ammonia is generally used as a denitrification reducing agent. With the development of the economy, people′s awareness of safe production has gradually improved, liquid ammonia has been listed as a major source of danger due to limited storage and transportation, ammonia can be produced by liquid ammonia heating vaporization, or can be indirectly prepared by ammonia evaporation or urea decomposition. Urea is not a dangerous good, transportation and storage are relatively safe, and ammonia gas can be produced when decomposed by heat. Therefore, the denitrification reducing agent is generally changed to urea.

    2023 S2 v.29 [Abstract][OnlineView][Download 2006K]
  • Effect of blending ratio on the fouling and slagging characteristics during combustion of Zhundong coal

    GUO Shuai;SONG Weijian;Institute of Engineering Thermophysics, Chinese Academy of Sciences;

    Wuhai coal was selected as the blending coal. Effect of blending ratio on the ash fouling and slagging characteristics during combustion of Zhundong coal was investigated. The fouling trend was characterized by sodium release and ash compositions, while the slagging trend was characterized by ash compositions, ash fusion temperatures and composite index. The results showed that the content of nitratine was relatively high in Zhundong ash, while kaolinite and quartz were predominant in Wuhai ash. With increasing ratio of blending Wuhai coal, the release of sodium gradually reduced, and the maximum reduction was 47.85%.Meanwhile, the percentage of nepheline minerals gradually reduced as well, and those mineral peaks were absolutely disappear at a ratio of 30%. With increasing ratio of blending Wuhai coal, the ratio of alkali/acid gradually reduced; the percentage of infusible minerals gradually increased, and at a ratio of 30%, quartz, anhydrite, hematite were predominant in ash. T_D presented a sharply increase and then remained basically unchanged. The value of composite index gradually reduced, and its value was located within the interval of slight slagging. It verified that the appropriate blending coal could effectively solve ash fouling and slagging. Taking ash fouling and slagging into consideration, the best blending ratio of Wuhai coal is 30%.

    2023 S2 v.29 [Abstract][OnlineView][Download 1932K]
  • Characterization of slagging about high alkali metal fuel ash

    TAN Xuemei;SHI Jian;HU Nan;ZHAO Pengshan;ZHANG Man;YANG Hairui;Department of Energy and Power Engineering,Changchun Institute of Technology;Department of Energy and Power Engineering,Tsinghua University;Shanghai Boiler Works Co., Ltd.;

    Due to the high alkali metal in the Zhundong coal and biomass, it will cause slagging of the heating surfaces in boiler during combustion which influences the long-time safe operation of the boiler.The ash fusibility temperature is used to guide the boiler design and operation.On the project, the GB/T 219-2008 Determination of fusibility of coal ash is used to measure the four characteristic temperatures to describe the varation of ash fusion.So as to judge the characteristics of slagging.However, the measured value is so higher than actual value evidently because of the release of alkali metal that failue to guide the boiler operation.In order to acquire accurate datas, the release characteristic of alkali metal are summarized.The 20%-50% of Na releases at 550 ℃ and to 815 ℃, the releases arrive to 30%-80% in Zhundong coal.From 400 ℃ to 800 ℃, the K releases almost completely.The GB method is further analyized, the production process of low temperature ash decrease the release of alkali metel, but still release during the measurement.So the GB method is unsuitable for characterization of fusibility about high alkali metal fuel ash.Aimed to high alkali metal fuel, the measure method is proposed which adopted the low temperature ash to determine the initial sintering temperature by pressure-drop method.Before the sintering, the pressure-drop in the chamber increase with the increase of temperature which adapt to dacy′s low. When the sintering occurs, the ash will shrink, the pressure-drop will decrese quickly.Usually, the temperature of break point is the initial sintering temperature, also is the minimum temperature of ash fusion and agglomeration.The low temperature asher is used to produce low temperature rice husk ash and determine the initial sintering temperature that is 695 ℃ which is close to the value in engineering.But the result of GB method is 1 500 ℃ above, which is higher than actual slagging temperature.Preliminary suggest that the pressure-drop method could be used to judge the slagging of high alkali metal fuel and guide industrial application.

    2023 S2 v.29 [Abstract][OnlineView][Download 1921K]
  • Economical research on combined deacidification of waste incineration flue gas

    QUE Zhengbin;LI Debo;XIAO Xianbin;MIAO Jianjie;CHEN Tuo;CHEN Zhihao;CHEN Zhaoli;FENG Yongxin;National Engineering Laboratory of Biomass Power Generation Equipment, North China Electric Power University;China Southern Grid Power Technology Co., Ltd.;College of Power Engineering, North China Electric Power University;

    Incineration power generation is the main method of domestic waste disposal in China, but acid gas will be generated during the incineration process, and measures need to be taken to ensure that the discharge meets the standard. At present, the mainstream deacidification process is to use the semi-dry deacidification technology alone. With the increasingly strict emission limit requirements, the combined deacidification process has become the future development trend. At present, there are few studies related to the combined deacidification process of waste incineration flue gas, and it is not comprehensive and in-depth. In order to obtain a more comprehensive economic research result of the combined deacidification process of waste incineration flue gas, a material balance calculation model, heat balance calculation model and a combined deacidification process calculation model of a waste incineration power plant were established, combined with a domestic waste incineration power plant were establisbed. Design parameters and operating data were used to carry out computational studies on different combined deacidification processes. Focusing on meeting emission requirements and operating stability, the combined deacidification process is generally better than the single deacidification process. Key comparison of cost calculation results show that in the specific selection of the combined deacidification process, some semi-dry + dry combined deacidification processes can meet the design emission requirements and should be given priority; some semi-dry + dry combined deacidification processes cannot meet the requirements. Ultra-low emission requirements can be selected between the semi-dry + wet combined deacidification process and the dry + wet combined deacidification process. Finally, the method suitable for the combined deacidification process is further summarized and selected to provide a reference for the design and operation optimization of the combined flue gas deacidification process of the waste incineration power plant.

    2023 S2 v.29 [Abstract][OnlineView][Download 1888K]
  • Sample purification method for determination of PAHs in fly ash

    YANG Ruiming;Key Laboratory for Thermal Sciences and Power Engineering of Ministry of Education, Tsinghua University;Department of Energy and Power Engineering, Tsinghua University;

    The sample purification method of the extracting solution from the determination of PAHs in the fly ash of coal power plant, the solid phase extraction column is used for purification. According to the working principle of the column, the working steps of the column are optimized. For the component loss caused by the precipitate in the solvent conversion of the extract, the quantitative determination is carried out. It is determined that the loading solution needs to be retained, and the difference between the rinsing and elution steps is clarified. Thus, the working steps of the SPE column are determined, The purification effects of different SPE columns were compared, the accuracy of the method was verified with actual samples, and it is found that the silicon column has the best purification effect. The purification method has simple operation, small experimental workload and accurate results, which can improve the accuracy of testing polycyclic aromatic hydrocarbon organic pollutants in fly ash of fixed pollution source, and its optimization process alsohas reference significance for similar applications.

    2023 S2 v.29 [Abstract][OnlineView][Download 1861K]
  • Effect of evaporation and salt precipitation of desulfurization wastewater on fly ash viscosity

    WU Quan;CHN Energy New Energy Technology Research Institute Co., Ltd.;

    The evaporation of desulfurization wastewater releases salt, which affects the viscosity of fly ash and leads to serious ash deposition in the flue. In order to clarify the influence of different salts evaporated from wastewater on the viscosity of fly ash, the viscosity of fly ash under different working conditions was analyzed by viscous force test balance, and the surface morphology of the sample was analyzed by scanning electron microscope. The results show that the desulfurization wastewater significantly enhances the bonding strength of fly ash, and the bonding strength of fly ash samples added with desulfurization wastewater is 5.1 times that of fly ash samples added with deionized water. Magnesium ion in wastewater has the greatest influence on the bonding strength of fly ash, and the bonding strength of magnesium chloride sample is 2.36 times that of deionized water sample. With the increase of salt content in the sample, the bond strength of fly ash increases significantly. Under the micro morphology, it is observed that the inorganic salts evaporated from the desulfurization wastewater adhere to the surface of fly ash particles in the form of cluster agglomerates, forming a coating structure, forming a stable bonding force between particles, and the agglomerated structure is compact. In conclusion, the inorganic salts evaporated from desulfurization wastewater enhance the viscosity of fly ash, change the surface morphology of fly ash, induce fly ash agglomeration, and then aggravate the deposition of flue fly ash.

    2023 S2 v.29 [Abstract][OnlineView][Download 2055K]
  • Melting process characteristics and energy saving optimization of waste incineration fly ash mixed coke powder

    LI Pengfei;ZHAO Wenqiang;YANG Fengling;ZHANG Peihua;Shanxi Dadi Haike Environmental protection Technology Co.,Ltd;Shanxi Dadi Environment Resources Limited Company;Collaborative Innovation Center of High Value—added Utilization of Coal-related Wastes,State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste Resources,Shanxi University;Shanxi Gemeng China-US Clean Energy R&D Center Co.,Ltd.;

    In recent years, the harmless treatment capacity of domestic garbage in China has been improved year by year, and the incineration capacity of domestic garbage has gradually increased, the amount of waste fly ash produced has also increased significantly. The industrial by-product coke powder and waste incineration fly ash were mixed for melting treatment, and the coke powder combustion was used to provide part of heat for the melting process, so as to reduce the energy consumption of waste fly ash melting disposal process.The characteristics of melting process and solidification effect of heavy metals in slag under different mixing ratio and cooling conditions were investigated by analyzing phase composition, microstructure and leaching characteristics of heavy metals in slag.According to the laboratory compound melting optimization conditions, the melting process model was built by Aspen Plus to simulate the melting process under different proportions of fly ash and coke powder, calculate the whole process energy consumption, and obtain the optimization conditions of the compound melting process.To effectively reduce the waste incineration fly ash fusion treatment energy consumption, to achieve a wide range of industrial application to provide technical support.

    2023 S2 v.29 [Abstract][OnlineView][Download 2880K]
  • Effect of citric acid on crystallization properties of gypsum

    LI Xiaofeng;DU Mingsheng;HE Xiangyu;XIAO Haiping;Datang Environment Industry Group Co.,Ltd.;School of Energy Power and Mechanical Engineering,North China Electric Power University;

    The nucleation experiment and crystal growth experiment of gypsum were carried out in this study to explore the principle of the influence of citric acid on the crystal quality of desulfurized gypsum, which was conducive to the high quality resource utilization of desulfurized gypsum. The nucleation experiment of gypsum crystals show that citric acid prolongs the crystallization induction time and inhibites the nucleation rate. In blank condition, the induction time is 38 min when the suoversaturation ratio is 2.3. The smaller the suoversaturation ratio is, the more obvious the prolonging effect of citric acid on induction time is, and the larger the nucleation inhibition index of citric acid is. With different suoversaturation ratio, citric acid can prolong the crystallization induction time by 4.8-6.9 times, and the inhibition index of gypsum crystallization nucleation is 76.1%-89.6%. Citric acid inhibits the nucleation of gypsum crystals. The growth experiment of desulfurized gypsum crystal show that the median particle sizeof gypsum crystal is 39.738 μm in blank condition, and the particle size of gypsum crystal increases by 79.28% when citric acid is added. When citric acid and seed are added at the same time, the particle size of gypsum is increased by 288.66% compared with the blank condition. Morphology analysis show that the length of gypsum crystal decreases and the width increases after citric acid is added. When seed crystals and citric acid are added at the same time, the gypsum crystals grows stronger and showed lamellar structure. The adsorption of Ca~(2+) by carboxyl groups in citric acid transforms gypsum from fine needle to short column. Therefore, citric acid inhibits the nucleation process of gypsum crystals, promotes the short columnar growth of gypsum crystals and improves the quality of gypsum.

    2023 S2 v.29 [Abstract][OnlineView][Download 2054K]
  • Effect of coal combustion flue gas on the oxidation characteristics of SO_2 by commercial SCR catalyst

    YANG Xigang;XU Yueyang;WANG Sheng;LI Yuxin;LI Jinlei;WEI Zekun;HUANG Yaji;ZHANG Rongchu;State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control (China Energy Science and Technology Research Institute Co., Ltd.);School of Energy and Environment,Southeast University;Nanjing Changrong Acoustic Inc.;

    As a common commercial SCR catalyst used by most coal-fired power plants, V_2O_5-WO_3/TiO_2 can oxidize the SO_2 in flue gas to SO_3, which in harmful to the safe operation of SCR denitration and subsequent equipment. The effects of temperature and flue gas components on the SO_(2 )catalytic capacity of SCR catalyst were explored based on a fixed-bed reactor. The results show that operation temperature and O_2 concentration greatly affects the SO_3/SO_2 conversion rate. When O_2 concentration is 0-4%, the SO_3/SO_2 conversion rate increases with O_2 concentration while almost do not change when it is over 4%. The diffusion rate and oxidation rate of SO_2 jointly determine the SO_3/SO_2 conversion rate. When SO_2 concentration is between 0-100×10~(-6), the conversion rate of SO_3/SO_2 increases with SO_2 concentration under the oxidation of SCR catalyst. However, SO_3/SO_2 conversion rate starts to decrease when the SO_2 concentration is higher than 100×10~(-6). The denitrification process has a significant effect on the oxidation of SO_2, which mainly manifests as the competitive adsorption of NH_3 and SO_2 on SCR catalyst.When the ammonia nitrogen mole ratio is less than 1, the denitration efficiency increases with the ammonia/nitrogen ratio while the of SO_3/SO_2 conversion rate decreases. When the ammonia-nitrogen ratio is greater than 1, the denitration efficiency almost do not change, while the of SO_3/SO_2 conversion rate startes to increase noticeably.

    2023 S2 v.29 [Abstract][OnlineView][Download 1947K]
  • Ultra-low emission modification of 600 MW supercritical circulating fluidized bed boilers unit

    WANG Xueshen;XIN Shengwei;GAN Zheng;DUAN Caili;WANG Hu;Sichuan Baima CFB Demonstration Power Plant Co.,Ltd.;CFB Technology R & D Center,CHN Energy Group;Guoshen Technical Research Institute,CHN Energy Group;

    From the perspective of technology maturity and technology economy, the ultra-low emission transformation technology route of 600 MW supercritical CFB boiler unit was demonstrated, that was adopting high efficiency desulfurization and low nitrogen combustion in furnace, selective non-catalytic reduction(SNCR) denitration technology and semi-dry desulfurization and dust removal integration process outside the furnace.It has good investment and operation economy and can adapt to the future development trend of environmental protection. The semi-dry desulphurization and dust removal system outside the furnace adopts the double tower design and sets the pre-electric dust collector, which belongs to the first one in China. The removal effect of SO_2 was verified by numerical simulation, and the switching control of single and double towers and the cooperative desulphurization operation mode inside and outside the furnace were optimized, which can further improve the boiler operation economy. The research results can provide a reference for the selection of ultra-low emission modification for 660 MW ultra-supercritical CFB boiler units.

    2023 S2 v.29 [Abstract][OnlineView][Download 1974K]
  • Influence of flue gas condensation on the synergistic removal of condensable particulate matter in coal-fired units

    LIU Linhu;YANG Yongbin;FENG Xiaofeng;SUN Haibin;KOU Hairong;ZHAO Chenguang;ZHANG Wenlong;WANG Xiao;YUAN Yuan;ZHANG Shuangping;Yangcheng International Power Generation Co.,Ltd.;Datang Northwest Electric Power Test & Research Institute;

    As the mainstream technology of large-scale application, flue gas condensation recovery of flue gas water resources is the main method of flue gas water resources recovery. This method can condense condensable particulate matter and effectively achieve the synergistic removal of condensable particulate matter. The removal effect of saturated wet flue gas at the desulfurization outlet on condensable particulate matter under different condensation degrees was studied through experimental methods, so as to provide relevant reference for the control degree of condensable particle removal. The results show that the flue gas condensation system can significantly remove the condensable particulate matter in the flue gas, and the removal efficiency increases with the decrease of condensation temperature. When the flue gas supersaturation is less than 2, the increasing trend of condensable particle removal efficiency slows down significantly with the increase of condensation degree, and heterogeneous condensation is the main form at this time. When the flue gas supersaturation is greater than 2, the increasing trend of condensable particle removal efficiency is significantly strengthened with the increase of condensation degree, and the condensation of wet flue gas steam begins to enter homogeneous condensation. When the supersaturation of flue gas reaches 3.39, the removal efficiency of condensable particulate matter can reach 81.10%.

    2023 S2 v.29 [Abstract][OnlineView][Download 1911K]
  • Study on adsorption mechanism of carbonaceous adsorbent for organic matter in wastewater from coal pyrolysis

    LU Guoliang;WANG Luping;CAO Song;LI Guangyu;State Key Laboratory for Efficient Utilization of Coal and Green Chemical Industry Jointly Constructed by the Ministry and the Province,Ningxia University;

    The cascade utilization of low rank coal is an important direction of coal chemical industry development and an important way to achieve clean and efficient transformation of coal. However, tar and phenol will be produced when the reaction temperature is relatively low during the pyrolysis of low rank coal. Usually, the oil-water separation process cannot completely separate them, so some harmful substances will be brought into the water, increasing the difficulty of wastewater treatment. Adsorption is the simplest and most direct method to treat coal pyrolysis wastewater, and the treatment effect is stable. Taking this wastewater as the research object, the feasibility of treating wastewater with carbonaceous adsorbent was explored by adopting adsorption method and selecting four adsorbents, namely commercial activated carbon, lignite fine coke, bituminous coal fine coke and amorphous activated coke. Charcoal adsorbent has similar surface element composition and carbon element combination form, but its specific surface area, average pore diameter and other parameters are obviously different. Through sequencing batch experiment, it is proved that within a certain range, the greater the dosage of adsorbent, the longer the adsorption time, and the smaller the pH, the better the removal effect of COD in the water sample. The removal efficiency of long chain hydrocarbons by commercial activated carbon and lignite fine coke is much higher than that of amorphous activated coke. The adsorption kinetics and thermodynamic process of the adsorbents on organic matters were analyzed theoretically. It is found that the adsorption kinetics of the four adsorbents on pollutants can be described by a quasi second order kinetic model, and the adsorption rate is jointly controlled by the diffusion process in the particles and the diffusion process in the liquid film. Langmuir isotherm adsorption model can better describe the adsorption behavior of organic substances on the adsorbent. The adsorption process is mainly single-layer adsorption, which is a spontaneous, exothermic, entropy reducing process, and mainly physical adsorption.

    2023 S2 v.29 [Abstract][OnlineView][Download 2176K]
  • Physicochemical characteristics and heavy metal leaching toxicity of incineration fly ash from different waste incinerators of domestic waste

    ZHAO Fengwa;MA Xiaodong;DA Yongqi;FENG Yun;HE Tingshu;LI Zongyang;Anhui Conch Environment Protection Group Co.,Ltd.;College of Materials Science and Engineering,Xi′an University of Architecture and Technology;Fuping Haichuang Yaobai Environmental Protection Technology Co.,Ltd.;

    The mechanical grate type and circulating fluidized bed type are commonly used in the municipal solid waste incinerators in China. There are few reports about the differences in the physicochemical characteristics of incineration fly ash produced by different furnace. Hence, the physicochemical characteristics of different incineration fly ash, such as the phase compositions, microstructure, pores and its specific surface area were compared with XRD,SEM,BET,ICP-MS,and other analytical methods. The leaching toxicity of fly ash was compared and analyzed through a toxicity leaching test. The results show that compared with fluidized bed ash(CFB ash),grate ash(GF ash) has a larger specific surface area, more internal pores, higher calcium and chlorine content, lower silicon and aluminum content, and more spherical microstructure. CFB ash contains more Cr, Mn, Ni, Cu, and Sb heavy metal ions, while GF ash contains more Zn, Cd, and Pb heavy metal ions. Specific surface area of GF ash is 3.45 times greater than CFB ash, and they are much greater than cement, which provides conditions for the adsorption of heavy metal ions.In addition to common phase components, GF ash contains hydroxyapatite, while CFB ash contains Gismondine and Hydroxylapatite. The pH of GF ash and CFB ash are higher than 10.7,the mass fraction of dioxin exceeds 98 ng TEQ/kg, and there are safety problems that the leaching toxicity of heavy metal ions exceeds the standard limits. Therefore, to achieve efficient resource utilization of municipal solid waste incineration fly ash, before ensuring environmental safety the differences in physicochemical characteristics of incineration fly ash produced by different incinerators should be comprehensively considered to explore the best disposal method of this fly ash.

    2023 S2 v.29 [Abstract][OnlineView][Download 1969K]
  • Research progress on high moisture industrial solid waste resource combustion disposal and utilization technology

    ZHENG Xinyu;SHANG Manxia;KE Xiwei;WANG Suilin;ZHANG Man;HUANG Zhong;Department of Energy and Power Engineering,Tsinghua University;School of Environmental and Energy Engineering,Beijing University of Civil Engineering and Architecture;

    High temperature combustion is a common disposal method of industrial waste, which has the advantages of being clean environmentally friendly, efficient, economic and environmental protection. The latest research progress of high-moisture industrial solid waste recycling technology was reviewed, the characteristics and co-combustion characteristics of typical high-moisture industrial solid waste were introduced, and the disposal process, pretreatment method, incineration method and disposal effect were analyzed and compared. The research shows that blending co-combustion is an effective method to deal with high moisture industrial solid waste. The effects of before and after blending and blending at different ratios on boiler operation were compared. Among high moisture industryal solid wastes, indirect drying + circulating fluidized bed boiler co-combustion should be adopted for sludge, and direct pumping combustion should be adopted for coal sludge. For special fuels such as sediment, further research should be strengthened.

    2023 S2 v.29 [Abstract][OnlineView][Download 2141K]
  • Effect of sodium on NO heterogeneous reduction by char in high temperature reduction zone

    WU Hailong;WEI Lihong;ZHENG Huilong;LI Qiangqiang;CUI Baochong;College of Energy and Environment,Shenyang Aerospace University;Institute of Engineering Thermophysics,Chinese Academy of Sciences;Aerospace Center,Weiqiao National Academy of Advanced Technology;

    China has rich reserves of high alkali coal, which is mainly stored in Zhundong, Xinjiang. High alkali content causes problems such as slagging and fouling of boiler heating surface. Pyrolysis is an important method to achieve efficient and clean utilization of low rank coal. Heterogeneous reduction of NO by char in high temperature reduction zone is a kind of furnace denitration technology with broad application prospects. Mineral Na in Xinjiang high alkali coal significantly affects the heterogeneous reduction of NO by char, while the existing research on the impact of alkali metal Na on the microstructure of coal char under high temperature conditions and the impact of heterogeneous reduction of NO by char is still unclear. Therefore, Xinjiang Jiangjunmiao coal was selected as the experimental sample, and the pretreatment method of adding Na by external impregnation after acid washing and deashing was adopted. The influence of Na on the microstructure of char was analyzed by XRD and BET, and the influence of Na on the reaction process of heterogeneous reduction of NO by coal char was studied by means of a high-temperature horizontal tube furnace system. There are six kinds of coal chars, including deashing coal chars and coal chars impregnated with 0.2%, 0.6%, 0.8%, 1.0% and 2.0% NaCl. The experimental results show that the reaction temperature increases from 1 000 ℃ to 1 300 ℃, and the NO reduction rate of deashing char increases from 53.6% to 59.5%. At 1 300 ℃,the reduction rate of NO increases first and then decreases with the increase of Na content. Among them, 0.6% NaCl coal char has the strongest promotion effect, and the highest reduction rate of NO is 64.4%, but the coal char impregnated with 2.0% NaCl shows inhibition effect. The reaction temperature is increased from 1 000 ℃ to 1 300 ℃, and the NO reduction rate of 0.6% NaCl char is from 51.8% to64.4%. The catalytic action of NaCl is related to the reaction temperature, and 1 200 ℃ is a watershed. At low temperature(1 000-1 100 ℃), NO reduction of coal char loaded with 0.6% NaCl slightly lower than NO reduction of deashing coal char. At higher temperatures(1 200-1 300 ℃), NO reduction of coal char loaded with 0.6% NaCl are significantly higher than NO reduction of deashing coal char. The results of BET and XRD show that with the increase of reaction temperature, the pore structure of all chars changes, the aromaticity of the crystals increases, and the specific surface area decreases. At the same reaction temperature, with the increase of Na content,the aromaticity and specific surface area of the crystal increases first and then decreases. Under constant temperature, the catalytic action of NaCl is the main reason for the change of char activity, which destroys the correlation between char aromatic degree and reactivity. The pore structure and Na content of char determine the char reactivity. Temperature is the main factor affecting the char activity when the reaction temperature changes. Kinetic analysis show that Na do not change the properties of active sites on coal char surface but increases the number of active sites.

    2023 S2 v.29 [Abstract][OnlineView][Download 2111K]
  • Controls trategy for pollutants of circulating fluidized bed boiler units in AGC mode

    DUAN Caili;MA Chi;WU Wanzhu;XIN Shengwei;WANG Hu;CHN Energy Group Guo Shen Technical Research Institute;CHN Energy Group Guoyuan Power Co.,Ltd.;CHN Energy Group CFB Technology R & DCenter;

    Circulating fluidized bed(CFB) unit adopts integrated desulfurization and denitration technology in furnace, it is relatively easy to discharge pollutants up to standard. However, with the improvement of AGC(Automatic Generation Control) performance index requirements of the two rules, and new energy development requirements for peak regulation of thermal power units. AGC instructions change frequently. Affected by the automatic control of the unit and the refinement level of the operation personnel, the emission of SO_2 and NO_x is easy to exceed the standard. Through the analysis and research on the phenomenon of SO_2 and NO_x exceeding the standard of a 4×200 MW circulating fluidized bed unit when the AGC command changes frequently or greatly, a comprehensive collaborative optimization control was carried out. A series of optimisation strategies have been added, including automatic identification of large changes in the AGC command, automatic intervention in the AGC load change rate, attenuation of the impact of large changes in the AGC command on the combustion conditions, precise adjustment of the oxygen and secondary air volumes, early automatic pre-regulation of limestone, etc.,which have significantly improved the phenomenon of SO_2 and NO_x environmental parameters exceeding the standard under the AGC mode and improved the safety and stability and operating economy of the unit.

    2023 S2 v.29 [Abstract][OnlineView][Download 2152K]
  • Optimization on integrated removal technology of ceramic catalytic filter tubes

    TAN Zengqiang;ZHOU Mengwei;LIU Xipu;YAO Hao;NIU Yongjun;Huaneng Yangtze Environmental Technology Co.,Ltd.;

    The integrated removal technology of ceramic catalytic filter tubes is suitable for the simultaneous removal of SO_x,NO_x,and dust from biomass power plants, steel, coking, cement, glass furnaces, etc.,but the flue gas components are complex, which seriously affects the ceramic catalysis Chemical life of filter tubes. In order to solve the above problems, the pre-dust removal device before the integrated removal tower was studied, and the inlet structure of the integrated removal tower was optimized. The gas-solid two-phase flow calculation was carried out with Fluent software. The research shows that the gravity settling dust removal method is simple and the resistance is small, but it occupies a large area and requires a high space. The louvered dust removal device is simpler, and does not require modification to the original flue. The device occupies little space, but the resistance rises quickly when the guide vanes of this device are too dense. The overall structure of the small ash hopper fly ash separation device is relatively complex. By adjusting the triangular ash baffle plate, the distance between the small ash bucket and the small ash hopper can be adjusted to adjust the resistance of the device, and the space occupied is relatively concentrated, which does not affect the operation of subsequent equipment. When the inlet speed is 4.5 m/s, the overall ash removal efficiency reaches 75.1%.The inlet of the integrated removal tower is equipped with a composite infusion device to evenly distribute the incoming gas flow, the total differential pressure is about 249 Pa, and the airflow distribution coefficient is 0.12.

    2023 S2 v.29 [Abstract][OnlineView][Download 2095K]
  • MP-PIC simulation on inlet solid properties of the first-stage cyclones in an industrial fluidized bed reactor

    DU Zhenguo;WANG Xianpan;BAI Shiyu;PAN Haitao;GOU Rongheng;ZHANG Yongmin;CHN Energy Xinjiang Chemical Co.,Ltd.;State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Beijing;

    Fluidized bed reactors are widely used in petrochemical and coal chemical industries. In industrial fluidized bed reactors, multiple cyclone separators are usually installed in the top section of the freeboard for separating fine particles entrained in the gas leaving the reactor. Accurate predictions of the concentration and their size distribution at the cyclone inlets are crucial to properly design the cyclone systems with satisfied separation performance to the process requirement. MP-PIC simulations were first applied in an industrial fluidized bed reactor to simulate the solids entrainment in the freeboard. The simulation results indicate that, when there are cyclone separators installed, the gas velocity in the freeboard increases due to the reduced flow area and the cross-sectional uniformity of vertical gas velocity deteriorates in the freeboard. These factors lead to a substantially higher amount of solids entrainment than that without inside cyclone separators. This demonstrates that the inlets solids concentrations predicted by traditional correlations established based on laboratory-scale cold model experiment are much lower than the practical solids concentrations encountered in industrial cyclone separators. Moreover, the predicted size distributions at the cyclone inlets are also much different from those in the dense bed and the whole solids inventory. The average solids sizes at the cyclone inlets are much smaller.

    2023 S2 v.29 [Abstract][OnlineView][Download 2147K]
  • PSA separation performance of low concentration coal bed methane in composite bed

    GUO Haoqian;LI Xiaoliang;BAI Honghao;HE Ying;LI Xuefei;LI Yanfang;CCTEG China Coal Research Insfitute;Key Laboratory of Coal Efficient Utilization,Energy Saving and Emission Reduction Technology and Equipment;Beijing Key Laboratory of Coal Based Carbon Materials;

    In order to solve the problem of low utilization rate of coal bed methane with low water content, composite bed pressure swing adsorption process is used to separate low concentration coalbed methane. The composite bed pressure swing adsorption experimental device was used to analyze the impact of process conditions such as adsorption pressure, adsorption time, and the loading mass ratio of dehydrating agent and special adsorbent for CBM separation in the composite bed on the pressure swing adsorption performance of low water bearing CBM,and the optimal adsorption pressure, adsorption time and the loading mass ratio of dehydrating agent and special adsorbent were obtained. The experimental results show that: for low concentration CBM with atmospheric dew point of 25 ℃ and methane concentration of about 15%,in the process of pressure swing adsorption separation of composite bed, when the adsorption pressure, adsorption time and loading mass ratio gradually increase in the process of composite bed PSA separation, the separation performance of low concentration coal-bed methane increases first and then decreases. The best adsorption pressure is 600 kPa, the adsorption time is 180 s, and the loading mass ratio of dehydrating agent to special adsorbent is 0.3. At this time, the concentration of methane in the separated product gas is more than 30%,and the recovery rate of methane is more than 90%.

    2023 S2 v.29 [Abstract][OnlineView][Download 1883K]
  • MCDA framework for rural integrated energy systems with Game Theory and Fuzzy Grey Relational Projection method

    DU Ruoyun;NIU Dongxiao;YU Min;ZHOU Peiyan;School of Economics and Management,North China Electric Power University;Beijing Key Laboratory of New Energy and Low-Carbon Development;School of Energy Power and Mechanical Engineering,North China Electric Power University;

    With China′s "Carbon Peaking and Carbon Neutrality" goals, it′s urgent to shift energy utilization to clean and low carbon, and the rural integrated energy system(RIES) sustainable development evaluation is a blank research field. A multi-criteria decision-analysis(MCDA) framework based on Game Theory(GT) was proposed to improve the combination weighting and fuzzy grey relational projection method(FGRP) to evaluate the sustainable development potential of RIES. Firstly, a synthetical muti-criteria system of RIES from the perspective of technology, economy, social benefits, environmental protection, and resource utilization was propose, and the calculation method of each index was determined. Secondly, the modified comprehensive weighting method based on Game Theory was adopted to determine the index weights. Finally, the optimal sorting of schemes was carried out with FGRP. To validate the efficiency of the proposed framework, a rural integrated energy system project in Zhejiang Province was treated as a case to evaluate and verify the sustainability of three proposed rural integrated energy system planning schemes. The results demonstrate that the framework can realize the scientific evaluation of the sustainability of rural integrated energy systems.

    2023 S2 v.29 [Abstract][OnlineView][Download 2129K]
  • Treatment scheme of coal refuse discharge field fire area in Baode Coal Mine

    JIA Xiaoguang;General Control Room,CHN Energy Shendong Coal Group;

    In order to solve various environmental problems caused by spontaneous combustion of gangue piles in Baode Coal Mine, The idea of drilling and grouting at the top of slope was proposed. The treatment method is to drill holes and grouting in the treatment area, to reinforce the loose coal gangue accumulation area of the slope with cement-fly ash composite grout, to form a gravity-like retaining wall structure, and to put out the fire by grouting in the hidden fire area. After reinforcement, overburden soil is carried out on the regional slope. The goal of treatment is to completely extinguish the ignition point in the waste dump and eliminate the threat to the local ecological environment.

    2023 S2 v.29 [Abstract][OnlineView][Download 1895K]
  • Evaluation of mine ecological restoration effectiveness

    YAN Shi;MENG Xiangfang;MA Yan;LU Zhaohua;SONG Renzhong;HAN Xing;WANG Dangchao;Shenhua North Shengli Energy Co.,Ltd.;Institute of Restoration Ecology, China University of Mining and Technology,Beijing;School of Chemical & Environmental Engineering, China University of Mining and Technology-Beijing;Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta;

    The exploitation of mine resources not only promotes economic development, but also causes serious ecological problems. Under the background of vigorously promoting ecological civilization construction, mine ecological restoration has become the focus and difficulty of ecological restoration work. In this paper, the objectives of mine restoration, the effectiveness index system of mine ecological restoration. Meanwhile, the evaluation method system of mine ecological restoration are discussed, and the scientific effectiveness evaluation system of mine ecological restoration is put forward by comprehensively considering the socio-ecological-economic integrity of mine ecosystem. In addition, the methods of benefits evaluation and value calculation are introduced, and the concept, index construction, and data quantification of mine ecological restoration prospect, to provide a reference for the effective evaluation of mine ecological restoration and promote the sustainable development of mine ecological restoration. The effectiveness evaluation of mine ecological restoration can effectively identify and avoid the problems and hidden dangers in the ecological restoration work, which is of great significance to fill the evaluation method, improve the restoration technology and guide the follow-up treatment work.

    2023 S2 v.29 [Abstract][OnlineView][Download 1817K]
  • Analysis on slagging and fouling of circulating fluidized bed boiler burning Jordan oil shale

    LIU Zhihong;DU Xingquan;ZHANG Man;ZHOU Tuo;HUANG Zhong;GONG Yingli;JIN Yan;YANG Hairui;School of Electrical and Power Engineering,Taiyuan University of Technology;Department of Energy and Power Engineering,Tsinghua University;School of Chemical and Environmental Engineering, China University of Mining and Technology-Beijing;

    The 277 MW unit of Jordan Attarat Power Station is a circulating fluidized bed unit with the largest capacity of pure fuel shale in the world. In order to explore the causes of bed slagging and ash accumulation on the heating surface during its operation, the causes of bed slagging were clarified through experiments, and were further verified by Factsage calculation. At the same time, the reason of ash accumulation on heating surface was analyzed according to the actual situation. The results show that the large size of oil shale in the furnace or the poor fluidization of the air distribution plate leads to high local temperature and slagging of the bed. The local maximum temperature can reach 1 150 ℃, and the liquid mass accounts for 22% of the whole system mass. In addition, the ash content of oil shale is high. When the boiler fly ash flows through the convection heating surface at the tail, the joint action of thermal swimming and inertial collision leads to serious ash accumulation on the heating surface. Slagging can be effectively reduced by improving the grain size of oil shale, replacing the air distribution plate with reasonable structure and adjusting the primary air volume. The fouling problem of boiler heating surface can be effectively solved by changing the soot blower with higher efficiency and using ash remover.

    2023 S2 v.29 [Abstract][OnlineView][Download 1952K]
  • Analysis of energy-saving transformation and efficiency improvement of the primary fan of a 2×330 MW coal-fired unit

    WANG Shantong;SONG Wenqiang;WANG Qiusheng;TAN Houzhang;LYU Zhaomin;Guoneng Huizhou Thermal Power Co.,Ltd.;MOE Key Laboratory of Thermo-Fluid Science and Engineering,Xi′an Jiaotong University;

    In view of the low efficiency of the primary fan of a 2×330 MW coal-fired unit, the fan capacity check point(TB) parameters and the primary fan air volume margin based on the on-site fan thermal test measurement and the actual operation data of the boiler were corrected. The 3D model of the centrifugal fan was established by Solidworks software, and the flow field, pressure and impeller strength of the fan were simulated and calculated by means of Ansys-CFX software, and a high-efficiency fan blade shape matching the current power plant system was designed. The assembly clearance at the front end has been reduced, reducing volume losses. Finally, the field test measurement of the reconstructed primary fan system was carried out. The results show that the operating efficiency of the fan is increased from 57.44% to 81.86%,the deviation from the performance curve of the primary fan is reduced from 14.56% to 4.42%. The operating current of the primary fan is reduced by 13 A,the average input power of the primary fan motor decreased by 121.5 kW,and the effect of energy saving and efficiency improvement is remarkable.

    2023 S2 v.29 [Abstract][OnlineView][Download 2257K]
  • Modeling coal consumption of supercritical thermal power units based on multilayer perceptron neural network

    JIANG Jian;GONG Jun;XU Binchao;ZHANG Qi;ZHU Hengyi;TAN Peng;ZHANG Cheng;Guangdong Hongwan Power Generation Co.,Ltd.;School of Energy and Power Engineering,Huazhong University of Science and Technology;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

    Improving the operational flexibility of coal-fired thermal power generating units has become a reliable means to consume new energy into the grid at present, however, the characteristics of the frequent load and coal changes of coal-fired units have greatly increased the difficulty of unit operation optimization control, and there is an urgent need to develop a more intelligent and advanced operation optimization method. To improve the efficiency of unit operation optimization, a coal consumption modeling method based on multilayer perceptron neural network(MLP) was proposed, which integrated the coupling influence relationship between boiler-side and steam engine side parameters on coal consumption. A 660 MW supercritical thermal power unit was used as the modeling object, and 54 main operating parameters were selected as the input features of the model, including boiler-side main operating parameters, steam-engine side operating parameters and electrical-side operating parameters. 80% of the data were used for model training and the remaining 20% were used for model validation. EarlyStopping technique was used to monitor the root mean square error(MSE) of the training set,the number of network layers,the number of nodes in the hidden layer and the size of the training batch(batch_size) need to be optimized during the model training. In terms of the performance of the training and testing sets,97.69% and 97.67% of the absolute errors between the predicted and actual coal consumption values are between ±0.325 g/kWh,in which 62.22% and 61.22% are in the range of ±10.25 g/kWh,respectively.The MLP can replace the mechanism model for coal consumption calculation and lay the foundation for online real-time optimization.

    2023 S2 v.29 [Abstract][OnlineView][Download 1930K]
  • Application status and development direction of drop tube furnace used in hot model experiments of coal particles

    CHEN Zhipeng;WU Xiaoxiang;SHI Weikang;HU Yicen;MENG Enhao;LIU Xia;YU Guangsuo;Institute of Clean Coal Technology,East China University of Science and Technology;

    At present, the drop tube furnace system is widely used in the experimental research of pyrolysis, gasification and combustion process of coal particles with its advantages of small size, convenient operation and good simulation performance, so as to deeply understand the relevant characteristics and reaction kinetic mechanism of the coal samples, and provide experimental basis and theoretical guidance for the optimization of the actual industrial production process. The research progress of applying drop tube furnace to hot model experiments of pulverized coal was reviewed in recent years. The drop tube furnaces used now can be mainly divided into three categories: Gasifier type atmospheric drop tube furnaces, pressurized drop tube furnaces and two-stage drop tube furnaces. Various types of drop tube furnaces are used in different experimental studies for their different structures and functions. Based on the analysis of these three types of drop tube furnaces application status and the simulation of particle settlement inside the furnace, the writer further analyzes the problems existing in the drop tube furnaces at present. Finally, three improvement directions are put forward: expanding the simulation capability, strengthening comprehensive temperature monitoring and maintaining stable particle sedimentation, so that the drop tube furnace system can play a greater role in future research.

    2023 S2 v.29 [Abstract][OnlineView][Download 2130K]
  • Corrosion mechanism of high temperature slag on cone bottom brick of coal water slurry gasifier

    BAO Jinyuan;DAN Shulin;LIU Kecun;LIU Zhen;PENG Baozi;CHN Energy Yulin Chemical Industry Co., Ltd.;National Institute of Clean-and-Low Carbon Energy,Beijing;

    The short life of cone bottom brick of coal water slurry gasifier has always been one of the key problems, which restrict the long-term and stable operation of gasifier and the corrosion of cone bottom brick is very easy to cause the damage of quench ring and downcomer in gasifier. The gasification feedstock and the discharged slag of a 3 000 t/d GE gasifier in a plant were analyzed. The results show that the viscosity of discharged slag is larger as compared to the initial ash sample at the same temperature, which suggests that the viscosity-temperature relationship of the discharged slag should be used as the reference for the operation temperature of the gasifier to ensure that slag can flow during operation. The corrosion cone bottom brick in industrial gasifier were also analyzed by using the XRD, SEM and EDS. The results show that the composition of the slag hanging on the surface of the cone bottom brick is mainly elongated stone and diopside, and the high-temperature slag has strong penetration into the cone bottom brick, and can react with Cr_2O_3 and ZrO_2, and the destroyed matrix structure is the key factor for causing the corrosion of high chromia refractory. In addition, many cracks have been also found inside the cone bottom brick. The analysis results shows that the main substances in the cracks are calcium phosphate and anorthite. The discovery of calcium phosphate confirms that the matrix of the cone bottom brick may exist residual aluminum phosphate(AlPO_4), which makes CaO in the slag react with aluminum phosphate(AlPO_4) to produce calcium phosphate and alumina. However, the formation of calcium phosphate and anorthite lead to the mass ratio of CaO and SiO_2 penetrated into the high chromium brick matrix reduced, which cause the formation zircon because the reaction on the surplus SiO_2 with monoclinic zirconia in high chromium brick. Therefore, the thermal shock resistance of high chromium brick became poor.

    2023 S2 v.29 [Abstract][OnlineView][Download 2302K]
  • Transformation of Japanese Mistubishi unit low pressure cylinder zero output heating

    SHAO Jianlin;ZHAO Yanbo;ZHANG Junfeng;BAI Jie;REN Xuewu;YAN Baolin;ZHAO Ze;Sanhe Power Generation Co.,Ltd.;School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing;

    The western and northern regions of China are rich in all kinds of renewable energy and have great power generation potential. However, the fluctuating power access generated by renewable energy will cause many problems, such as operation stability, power quality and so on. The participation of coal-fired power plants in deep peak shaving is the most practical and feasible way to absorb renewable energy on a large scale. At the same time, there is a large heat source gap in the West and north areas, which seriously affects the lives of residents. Low pressure cylinder zero output heat supply technology, that is, under the condition of high vacuum operation of low pressure cylinder, completely sealed hydraulic butterfly valve is used to cut off the steam inlet of the original steam inlet pipe of low pressure cylinder, and a small amount of cooling steam is introduced through the new bypass pipe to take away the blast heat generated by the rotation of low pressure rotor after cutting off the steam inlet of low pressure cylinder, so as to realize the zero output operation of low pressure cylinder of the unit. Greatly reduce the cooling steam consumption of low-pressure rotor, improve the electromechanical peak shaving capacity and heating steam extraction capacity of steam turbine, and finally effectively solve the "three limits" problems of low-pressure cylinder cooling steam flow limit, limited electric peak shaving capacity and limited heating steam extraction capacity. However, under the zero output operation condition of low-pressure cylinder, only a small amount of cooling steam is introduced into the steam turbine, so that the original design flow field is damaged, which will have a significant impact on the safety of last stage and secondary last stage blades, and there are potential safety hazards. The mitsubishi TC-2F-40.5 unit with high installed capacity in China as an example was toke, with the help of computational fluid dynamics(CFD) The simulation analysis method was used to check the safety of temperature and dynamic stress, and it was proposed that the low-pressure cylinder water spray desuperheating system and water corrosion resistant metal wear-resistant coating can be adopted to ensure the long-term stable and safe operation of the unit under zero output condition.

    2023 S2 v.29 [Abstract][OnlineView][Download 2109K]
  • Coordinated development mechanism and market-oriented reform of coal and electricity in China

    WANG Yanbing;FENG Lezhen;Distribution Center,CHN Energy Group Shendong Coal Group;Ordos No.3 Middle School;

    As a primary energy, coal is mainly used to convert energy into secondary energy power. Coal accounts for about 70% of China′s electricity generation. As the main fuel of electricity, there is always a contradiction between coal and electricity. The main reason is that China′s electricity price is not set by the market, and coal, as a policy resource, cannot be allowed to develop freely in full accordance with market rules. The national macro-control plays an important role in balancing the contradiction between coal and electricity. The supply and demand relationship of coal and electricity, the history of coordinated development of coal and electricity were analyzed. The reasons for high coal prices in 2021 were analyzed, and a mechanism was found to solve the coordinated development of coal mines and electricity. The results show that the integration of coal, electric power and chemical industry, and the merger and joint venture of the three are the new direction of the reform and development of energy groups in the future.

    2023 S2 v.29 [Abstract][OnlineView][Download 2133K]
  • Mechanism and structure-activity relationship of vegetable oil collectors to enhance the low rank coal flotation

    HAO Yesheng;LIU Jincheng;BAO Xicheng;ZHANG Yuanming;XIA Yangchao;XING Yaowen;GUI Xiahui;National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology;China School of Chemical Engineering and Technology,China University of Mining and Technology;

    The large-scale separation and utilization of low rank coal generates a large amount of fine-grained and difficult to float coal slime. The development and use of flotation collectors containing polar components can accurately regulate the surface hydrophobicity of low rank coal particles, achieving enhanced flotation process of fine-grained and difficult to float coal slime. The physical and chemical properties of two kinds of vegetable oils JC61, JC62 and diesel oil as well as the flotation effect of low rank coal were studied, and the influence of different collectors on the wettability of low rank coal was explored by means of macroscopic characterization tests. Further, the Structure-activity relationship of ester collectors corresponding to flotation was summarized by theoretical calculation. The flotation test results showed that at a dosage of 2 000 g/t, the flotation concentrate yields of JC62, JC61, and diesel were 24.11%, 76.03%, and 89.92%, respectively. The collection performance of the two vegetable oils was significantly better than that of diesel. XPS testing found that JC61 and JC62 interact with particles to reduce the relative content of hydrophilic groups, and JC62 has a better effect. The composition of JC61 is mainly C16~C20 Saturated fat acid ethyl ester, while JC62 is mainly methyl oleate containing unsaturated double bonds. The main ester molecules in both plant oils can form hydrogen bonds with low rank coal hydrophilic carboxyl groups. The adsorption energies of dodecane, methyl oleate, ethyl oleate, methyl hexadecylate, and ethyl hexadecylate are-95.64,-127.71,-124.73,-121.05, and-24.17 kJ/mol, respectively. The law of action intensity is: methyl ester>ethyl ester, unsaturated ester>saturated ester. In the molecular structure of ester collectors, the molecules containing polar ester head groups can spontaneously form hydrogen bonds with lower rank coal functional groups, and the role of methyl ester is stronger. The presence of unsaturated C=C bonds on hydrophobic carbon chains enhances the polarity of molecules and promotes the role of ester molecules at low rank coal hydrophilic water level points.

    2023 S2 v.29 [Abstract][OnlineView][Download 2135K]
  • Effect of water hardness on settlement characteristics of coal slime tailings

    SONG Wenge;YANG Juanli;CHEN Energy Shendong Coal Technology Research Institute;Information Technology Co.,Ltd.,China Coal Technology and Engineering Group;

    Water hardness has an important effect on the settling characteristics of coal tailings. The relationship between hardness of production water and settling property of slime water in coal preparation plant was studied. The mineral composition and water chemistry of slime water samples from five coal preparation plants were analyzed by using X-ray diffraction(XRD) and ion chromatography. The research results show that the hardness of circulating water in coal preparation plant is determined by the mineral composition of coal slime. The settling test shows that the water hardness of coal slime sample is closely related to the mineral composition, which can be used to evaluate the settling characteristics. Further research shows that the settling velocity of slime water and the light transmittance of supernatant increase with the increase of water hardness. On the curve of sedimentation rate and transmissivity, the slope gradually decreases. The sedimentation rate and light transmittance of five coal samples are consistent with the verification test results.

    2023 S2 v.29 [Abstract][OnlineView][Download 1846K]
  • Study on the influencing factors of coal slurry filter press process based on orthogonal design

    ZHANG Chen;MA Xiaomin;FAN Yuping;DONG Xianshu;CHEN Ruxia;College of Mining Engineering, Taiyuan University of Technology;State Key Laboratory of Mineral Processing;

    With the wid espread promotion of mechanised coal mining, the content of fine-grained coal slurry in raw coal is getting higher and higher, and the moisture is still very high after dewatering by pressurised filter.The new pressure dewatering test device developed by the company itself, combined with orthogonal test, extreme difference analysis and analysis of variance, was used to study the influence of pressure, feed concentration and particle size composition on the dewatering of coal slurry water, and further analysed the compression and forming characteristics of the filter cake. The results show that the particle size composition has the greatest influence on the dewatering rate of coal slurry, followed by the influence of feed concentration and the least influence of pressure. The three stages of the filter cake forming process were obtained through the analysis of the pressure-deformation relationship of the filter cake. It is found that the compression dewatering stage is closely related to the dewatering effect, and the Compression Dehydration Index(C_(DI)) is further defined The lower the C_(DI), the higher the compressibility of the filter cake, the greater the reduction of the thickness of the filter cake under the same pressure, and the lower the moisture. The optimum design parameters: pressure of 0.6 MPa, feed concentration of 200 g/L and particle composition of 0.045-0.125 mm, only 34.5 s into the compression dewatering stage, filter cake moisture of 15.12%, minimum cake thickness of 2.924 mm, high compressibility of the filter cake, and minimum C_(DI) of 3.59.

    2023 S2 v.29 [Abstract][OnlineView][Download 2080K]
  • Experimental study on flotation of a coal slime with new collector in Shanxin coal

    ZHOU Yanhong;NI Xiao;HE Chengyao;HE Long;XU Zhigang;ZHANG Dongmei;ZOU Qian;Kopper Chemical Industry Co., Ltd,Chongqing;

    The screening test and contact angle measurement of a slime in Shanxi Province shows that this slime has high fine particle content and serious sliming. The ash content of this slime is 25.41%, contact Angle measurement value of raw coal is 50.10, which is relatively hydrophilic and difficult to float.Combined collectors Flotilla~?111, Flotilla~?117 and No.0 diesel oil were used in the fractional release flotation test. When the cleaned coal ash was 9.5%, Flotilla~? 111 could increase the cleaned coal yield by 12.75% and the recovery rate of combustible body by 15.72%. When the cleaned coal ash was 12.5%,Flotilla~? 111 could increase the yield by 3.72% and the recovery rate of combustible body by 4.87%. The results show that Flotilla series reagents could significantly increase the yield and recovery rate of cleaned coal when the ash content of cleaned coal was 9.5%-12.5%.

    2023 S2 v.29 [Abstract][OnlineView][Download 1837K]
  • Feasibility study on quality improvement of slime flotation in Guotun Coal Preparation Plant

    LIU Xiaomei;Linyi Mining Group Heze Coal Electricity Co.,Ltd.Guotun Coal Mine;

    The particle size composition of the incoming flotation slime in Guotun Coal Preparation Plant is complex. It is distributed according to the law of "more at both ends, less in the middle". Coarse and fine particles have low ash content in flotation tail coal due to high probability of desorption and low probability of collision, and the loss of combustibles is serious. In order to improve the flotation efficiency, in response to the "de-sliming" policy of Linkuang Group Company. Taking the flotation feed of this coal preparation plant as the research object, flotation reagents and process optimization experiments were carried out. Through the chemical screening design, a high-efficiency flotation collector DJ2# was developed. The experimental study showed that DJ2#-ZQ1# is the best chemical combination, when the dosage of DJ2# and ZQ1# is 250、400 g/t respectively,using the flotation process of "one rough selection and one selection" flotation process, the flotation clean coal yield of 78.18% and ash content of 10.07% can be obtained.

    2023 S2 v.29 [Abstract][OnlineView][Download 1944K]
  • Preparation technology and slurry forming property of biomass coal water slurry

    SONG Yintao;LI Xueqin;CHI Liang;LIU Peng;LI Yanling;LEI Tinzhou;School of petrochemical engineering,Changzhou University;School of resources and environmental engineering,East China University of technology;Ethylene plant of PetroChina Jilin Petrochemical Company;

    Biomass coal water slurry fuel has the characteristics of high calorific value, good combustion characteristics and green environmental protection. It is a new energy and is of great significance to alleviate the world energy crisis. Based on the development and utilization technology of biomass, this paper comprehensively summarizes the research progress of domestic researchers in the preparation process of biomass coal water slurry, and analyzes the preparation process of coal water slurry with waste liquid and solid waste. Grasp the two main factors affecting the pulpability, and study the advantages and disadvantages of biomass as coal water slurry additive in pulping. Combined with the current research status of biomass coal water slurry in preparation technology and biomass additives, the development of biomass coal water slurry in the future is considered and prospected.

    2023 S2 v.29 [Abstract][OnlineView][Download 1806K]
  • Investigation on detection of technical condition of flotation agent for coal

    ZHANG Jilong;GAO Jianchuan;XU Lihong;ZHANG Zhijun;FU Simei;CHEN Weiwang;College of Mining Engineering, Taiyuan University of Technology;Engineering Research Center for Slime High Efficiency Separation by Shanxi "1331 Project";Society of Shanxi Coal Processing and Utilization;Coal Preparation and Processing Department, Shanxi Coking Coal Energy Group Co., Ltd.;

    The development of flotation agents greatly affects the process of slime flotation under the policy that is clean and efficient utilization of coal. It was mainly discussed that the feasibility of testing the technical requirements of flotation agents for coal. And it was analyzed that the use of detection index of flotation agents. It was found that the main purpose of the standard is to standardize the safe, environmentally friendly and efficient use of flotation agent in the coal process, through investigating the correspondence of each index. There are some key indexes, which flash point, toxicity, flotation cleaned coal quantity index and agents consumption coefficient, and other seven auxiliary indexes. It is found that the flash point≥60 ℃ is selected to ensure the safety in the working environment of flotation agent storage, transportation and use. And the flash point is inversely proportional to the content of VOCs. The inhalable toxicity was correlated with odor of flotation agent and the content of VOCs and benzene. The indicators are reflected flotation efficiency that flotation cleaned coal quantity index and agent consumption coefficient. It is very important to obtain test results and evaluate data. The evaluation of inhalation toxicity should be consistent with the reference standard. It should be detected which VOCs and benzene content in coal slurry under the optimal agent consumption.

    2023 S2 v.29 [Abstract][OnlineView][Download 1844K]
  • Application of triaxial acceleration sensors in fault diagnosis of vibrating screens

    WANG Bin;Research Institute of Shendong Coal Group;

    In order to real-time monitor the working situation of vibrating screen find the equipment failure accurately, and reduce the labor intensity of the manual inspection on site, the real-time status monitoring was carried out by setting the three-axis acceleration sensor to collect the intelligent analysis of vibrating screen. The sensor can accurately collect the vibration acceleration parameters in the three directions of X,Y and Z axes of the screen body, and the intelligent diagnosis software will filter, Fourier transform and velocity envelope analysis, etc. The envelope value trend graph on the equipment platform was formed by establishing the vibration state model of the screen body in combination with the actual vibrating screen parameters. When the vibrating screen body is abnormal, the free cloud diagnostic system will judge the fault and the exact location of the fault in time, and send early warning information to the maintenance personnel, which greatly improves the efficiency of the vibrating screen fault diagnosis and the safety of the field staff. The fault detection rate of vibrating screen and its timeliness have been greatly improved by field application verification. It has a positive effect on the automation and intelligence of the production practice of coal preparation plant.

    2023 S2 v.29 [Abstract][OnlineView][Download 1991K]
  • Research and application of fast switching system based on incoming raw coal

    GUO Jingzhong;YAN Xiaoyong;CHEN Guoqing;CHEN Ganyong;JIANG Feng;HE Lucan;YANG Hui;China Energy Group (Fuzhou) Thermal Power Co.,Ltd.;Guoneng Nanjing Electric Power Test & Research Limited;

    It is inevitable to burn non design coal in power plants. In order to burn more economic coal, a coal feeding system that can switch coal types online and in real time was developed. Based on the system, through industrial tests and data analysis, the impact on the pulverizing system and combustion, the coal blending mode under low load, the change of load increase rate and the economic benefits brought by the system were discussed. The results show that the high calorific value and low moisture coal and the low calorific value and high moisture coal of the coal mill are cut off each other based on the fast switching system of raw coal into the furnace, which has no impact on the pulverizing system and combustion safety. The fast switching system based on the incoming raw coal can effectively alleviate the problem of uneven combustion in the furnace caused by the small number of low load coal mills put into operation. Based on the fast switching system of incoming raw coal, the raw coal of mills B and C is switched from low calorific value coal to high calorific value coal, and the load increase rate can be increased by 13.20% under the same coal feeding mode. Based on the rapid switching system of raw coal into the furnace, the blending proportion of economic coal can be increased, so the economic income can reach more than 10 million.

    2023 S2 v.29 [Abstract][OnlineView][Download 2133K]
  • Lump coal separation technology in power coal preparation plant

    ZHANG Lei;Daliuta Coal Preparation Plant,CHN Shendong CoalPreparation Center;

    When designing lump coal separation in power coal preparation plant, generally only one section of separation and waste discharge is designed, which cannot meet the product quality while ensuring the maximum recovery of coal resources. When meeting the product quality, it cannot fully recover coal resources. In order to find the process combination used in lump coal separation in power coal preparation plant, the characteristics of common lump coal separation process were analyzed. The applicability problems of the separation process were discusse, and the disadvantages of the first stage separation of lump coal were analyzed. Results shows that the first stage separation of lump coal in power coal preparation plant ensures the product quality. When the dry base ash is less than 6.5%,the theoretical coal carrying rate of gangue can reach 5.62%,which is much higher than the general level of coal carrying rate of gangue.The traditional two-stage jigging main recleaning process, two-stage two product dense medium cyclone or dense medium shallow groove separation process, jigging heavy medium combined process and three product dense medium separation process have higher water and medium consumption than the main recleaning process of new lump coal jigging + intelligent dry separation gangue recleaning and main recleaning process of lump coal shallow groove heavy medium + intelligent dry separation gangue recleaning. The main recleaning process of lump coal jigging + intelligent dry separation gangue recleaning, the main recleaning process of lump coal shallow trough heavy medium + intelligent dry separation gangue recleaning, and the new lump coal separation process can theoretically maximize the recovery of coal resources while obtaining qualified products, which provides a new idea for lump coal separation in power coal preparation plant. Lump coal jigging +intelligent dry separation gangue recleaning process can solve the problem of high coal carrying rate of jigging gangue, which provides a direction for the transformation of the current jigging process system. The three product heavy medium cyclone separation process will have a wider application prospect, after solving the problems that the connecting pipe between the first section and the second section of the three product heavy medium cyclone separation process is easy to be blocked and the separation density of the second section is not easy to be adjusted in time.

    2023 S2 v.29 [Abstract][OnlineView][Download 1793K]
  • Quality and efficiency improvement process system in coal preparation plant

    WANG Yuhui;GUAN Haitao;ZHANG Zhongqiang;Shendong Coal Group Co.,Ltd.,CHN Energy;

    The main production process of coal preparation plant is the heavy medium shallow tank separation of 200-13 mm lump coal, and no separation of <13 mm fine coal. 13-6 mm raw coal has a high proportion and low ash content, so it can be directly used as power coal without separation and fine cleaning. This process has the problems of resource waste, low selection rate and single product variety, which greatly reduces the economic benefits of the enterprise. Therefore, through coal quality analysis and technical and economic comparison, a process transformation scheme was proposed. The coal was screened by a 6 mm classification screen, the substances on the screen entered the heavy medium shallow tank separator, and the fine coal under the screen was not separated. The coarse slime and fine slime were recovered by the slime centrifuge and pressurized filter, respectively. The main products are 200-25 mm clean coal, <25 mm fine clean coal and <6 mm under flip screen, mixed coal products after mixing coarse slime and fine slime. This transformation improves the raw coal selection rate and stabilizes the product quality by reducing the lower limit of the shallow trough separator. The economic benefit of the enterprise is directly improved through the addition of fine coal products to achieve the purpose of improving quality and efficiency.

    2023 S2 v.29 [Abstract][OnlineView][Download 2123K]
  • Research and application of mine coal quality intelligent management system

    GAO Fengli;Shendong Coal Distribution Center,CHN Energy;

    China′s coal mine resources still occupy a important position, and coal mine resources, as non-renewable energy, reduce consumption, improve utilization rate, and promote intelligent management in the new era is the key to achieving sustainable development. Taking the construction of coal quality management system of GHN Energy Shendong Coal Branch as an example, the key points and practical application content of the construction of mine coal quality intelligent management system of coal mining enterprises were summarized. With the support of intelligent technology and information technology, the intelligent mine coal quality management system was constructed, and architecture and application of intelligent management system were discussed. It effectively improves the level of mine coal quality control and management efficiency of coal mining enterprises.

    2023 S2 v.29 [Abstract][OnlineView][Download 1952K]
  • Present situation and prospect of coal preparation technology in Shendong area in New Era

    JIA Xiaoguang;Shendong Coal Group National Energy Group General Dispatch Office;

    In the continuous development and progress of society, the state pays more and more attention to the problems of environmental protection and safe production of industry, and makes stricter management and requirements on coal resources and their cleanliness, pay attention to the development and promotion of coal preparation technology. Among them, the coal mining area in Shendong area has the advantage of rich resources and large coal reserves, and has a large amount of chemical coal and high-quality thermal coal with low ash, low sulfur and extremely high calorific value, the coal in Shendong area is rich and diverse, and has a broad development prospect. its development prospect based on the analysis of the present situation of coal preparation technology in Shendong area in the new era was discused.

    2023 S2 v.29 [Abstract][OnlineView][Download 1790K]
  • Coal preparation technology and production management measures

    WANG Weiwei;National Energy Group Shendong Coal Distribution Center;

    At present, our energy structure is in a critical period of "shift and speed up",while coal is the main energy in our energy structure, accounting for more than 65% of our primary energy, at present, the country especially attaches importance to the clean and efficient application of coal, therefore, our coal resource application should be in a reasonable innovative development. The effective way to deal with coal resources efficiently is to scientifically optimize the coal preparation process in coal preparation plant so as to obtain more high-quality coal resources. At the same time, the optimization of the coal preparation process can also properly reduce environmental pollution problems, which is helpful to improve the quality and efficiency of coal preparation plant. This paper will take Bulianta coal preparation plant in Shendong area as an example, through the analysis of its coal preparation technology status and existing problems to explore the effective measures of coal preparation production management.

    2023 S2 v.29 [Abstract][OnlineView][Download 1790K]
  • Intelligent management status and optimization analysis of washing center equipment

    DONG Qifeng;National Energy Shendong Coal Distribution Center;

    With the development of the times, 5G technology, big data technology and the Internet of Things have spread rapidly, playing an irreplaceable role in all walks of life. Combined with the analysis of the development needs of modern society, although the new energy has been continuously developed, but coal is still a pillar of energy cannot be ignored. However, in the new era, the concept of green, pollution-free and environmental protection is deeply popular among people. Under this background, coal enterprises also carry out innovation and optimization, among which, the intelligent construction of washing center has become a key project, especially after the relevant national departments jointly issued the "Guidance on Accelerating the Intelligent Development of Coal Mines" in 2020. The intelligent construction of coal enterprise washing center has become an important component to facilitate the intelligent transformation of enterprises. However, from the actual effect, the intelligent construction of washing center is highly valued, but there are big problems in equipment management, and many enterprises have low management level. Based on this, this paper takes Shendong washing center as an example, through the analysis of its internal equipment management status and shortcomings, and then puts forward targeted optimization plan, and from the perspective of intelligent construction, puts forward a series of more advanced, intelligent and perfect modern equipment intelligent management mode, in order to provide support for the washing center of Chinese coal enterprises to further realize the goal of intelligent control.

    2023 S2 v.29 [Abstract][OnlineView][Download 1830K]
  • Transformation of intelligent control of heavy medium density in coal preparation plant

    WANG Zhenlong;ZHANG Jiabin;Shendong Coal Preparation Center,CHN Energy;

    In the actual production process of Kengkou coal preparation plant, system exist in the process of practical production methods density fluctuations, plant ash excess rate and poor which is high, the test cycle is long timeliness is not effectively guide the production in time, small test sample size easily affected by man-made factors, the results easy to distortion, sampling and testing problems in labor resources waste and safe hidden trouble. Install passive online ash measuring instrument on the clean coal belt, add and install on-line ash measuring instrument of raw coal belt source, transform and upgrade the centralized control system, connect the data of the two measuring instruments into the centralized control system, and control and adjust the parameter data of other gravity separation systems to form an automatic and intelligent separation system. The practice shows that the application of passive on-line ash measuring instrument to dense medium density control system can greatly improve the ability of dense medium washing system to deal with coal quality fluctuation.

    2023 S2 v.29 [Abstract][OnlineView][Download 1874K]
  • Application status and development trend of gravity dry separation technology

    LI Wenli;XIONG Chaoyuan;CHN Energy Shendong Coal Preparation Center;

    Coal plays a vital role in the economic development of the world as the primary energy. In recent years, hazardous elements emission from coal utilization has attracted considerable public concern due to its negative effects on human health and the ecosystem. During the whole process of coal utilization, coal preparation and separation is an initial and crucial stage for hazard emission control. Gravity dry separation technologies, as representative sorting methods, have advantages of high separation efficiency, water conservation, low investments, etc. Despite extensive industrial applications for about a century, there also remain limitations to overcome for the coal upgrading.

    2023 S2 v.29 [Abstract][OnlineView][Download 2003K]
  • Research and application of mine coal quality intelligent management system

    LI Kai;National Energy Group Shendong Coal Group Washing Center;

    In the process of the continuous reform and development of the social economy, the demand of the country for coal resources is more and more large, which also impels the coal industry of our country to be in the stage of high-speed development, but under the influence of the environmental protection idea, technology in the coal industry is also moving towards industrial automation, aiming to improve the utilization of coal resources while reducing environmental pollution. Based on the coal washing technology of Shendong coal preparation plant, this paper will explore and analyze the development status and problems of coal preparation technology, and to explore improvement measures.

    2023 S2 v.29 [Abstract][OnlineView][Download 1790K]
  • Development and application of density automatic control system for washing center in Shangyuquan coal mine

    BAI Long;SONG Wanjun;JIANG Hanyuan;LIU Qi;LI Xiaofeng;Shangyuquan coal mine of state energy group Guoshen company;

    The density control of the dense medium system in the washing center of Shangyuquan coal mine lags behind and is not timely, large amount of artificial media and low accuracy, the precision of semi-automatic control system is low and untimely, which leads to the instability of liquid level and density, the instability of separation effect of heavy medium separator, the increase of medium consumption and the high operation cost. The automatic medium flushing device using mobile jet technology replaces the original artificial machinery, and adds a medium preparation system independent of the original production system, which completes the medium feeding and cleaning in the idle state of the system introduction function, The logic control system of liquid level priority is developed, comprehensively considering the combination of different states of liquid level and density of medium mixing barrel, and the control relationship of adding medium, shunting and replenishing water is prefabricated from the perspective of dynamic development. So as to maintain the stable quality of the selected products, ensure the normal and stable operation of the sorting system, reduce the interference of human untimely factors, reduce the cost, make the quality of the selected products more stable, the normal and stable operation of the sorting system, and effectively control the production and coal quality accidents.

    2023 S2 v.29 [Abstract][OnlineView][Download 1978K]
  • Measures for improving quality of commercial coal in Wulan Mulun coal preparation plant

    HAN Guojun;Wulan Mulun coal Preparation plant,Shendong Coal Preparation Center;

    At present, due to the deterioration of the geological conditions of Wulan mulun Mine, the quality of raw coal is significantly worse, resulting in the current production organization of Wulan Mulun coal preparation plant is facing unprecedented difficulties. In order to find more adapt to the current production mode and methods, a series of commercial coal quality exploration and research. Starting with the ash reduction of commercial coal and precipitation, the existing process flow is optimized, and a better production mode is explored to maximize the benefits of the coal preparation plant and improve the quality and efficiency.

    2023 S2 v.29 [Abstract][OnlineView][Download 1786K]
  • Design of all-digital safety monitoring system for coal preparation plant

    ZHANG Xiaohui;WANG Heng;ZHAO Yuechuan;CHEN Xilong;Haragou coal preparation plant of washing center of Shendong Coal Group;China Coal Science and Technology Group Information Technology Co.,Ltd;

    At present, the safety monitoring system for domestic coal preparation plants has undergone three generations of development. At this stage, the safety monitoring system of coal preparation plants is mainly based on the single bus and RS485 polling method, and there are generally poor real-time communication, low reliability, and easy to be affected. electromagnetic interference, etc. In order to solve the above problems, the dual redundant structure based on the controller area network bus(CAN bus) and the industrial Ethernet ring network is adopted, the digital substation is used as the core of the whole system, and the ARM processor LPC2119 and the embedded operating system uC/OS-Ⅱ are used, respectively from the hardware design, the embedded program design of intrinsically safe digital substations, the development and design of the host computer monitoring software and the mobile APP,and designed a new generation of fully digital safety monitoring system for coal preparation plants. Through the test of related technologies based on the simulation test system built in the laboratory, the test results show that the system has the characteristics of strong real-time and reliability, high degree of intelligence and excellent economic performance, which can greatly improve the safety monitoring of existing coal preparation plants. The overall performance of the system advantageously guarantees the safe production of the coal preparation plant.

    2023 S2 v.29 [Abstract][OnlineView][Download 2214K]
  • Belt conveyor drum rupture cause analysis

    JIAO Zhao;CHN Energy Shendong Coal Preparation Center;

    Improveing the operation efficiency of the belt conveyor can reduce the belt conveyor drum failures and maintenance, reduce the frequency of electromechanical failures, and ensure stable production operation. Due to the multiple advantages of simple structure, convenient operation, easy maintenance, etc., the belt conveyor can be used for horizontal and inclined conveying in the coal preparation plant, which can save a lot of manpower and material conveying time.One of the key components of the belt conveyor is the drum. The drum quality, installation and use methods, daily maintenance and inspection are closely related to the service life and work efficiency of the belt conveyor. The drum category, structure, stress and relevant influencing factors were summarized, the reasons for belt conveyor drum cracking were analyzed, and the maintenance and improvement plan for belt conveyor drum was proposed, which provided a reference for coal preparation enterprises to prevent belt conveyor drum cracking.

    2023 S2 v.29 [Abstract][OnlineView][Download 1922K]
  • Feasibility of separation of bottom coal of Heidaigou coal mine

    LIU Libo;SONG Huan;SUN Haiyang;BAO Fengliang;China Energy Zhunneng Group Co.,Ltd.;Xi′an Grand Tang Engineering Technology Co.,Ltd.;Science and Technology Talent Bureau of Ordos High Tech Industrial Development Zone;

    In order to improve the comprehensive utilization rate of the bottom coal of Haidaigou coal mine, expand the utilization rate of green mining, promote the efficient extraction and utilization of coal resources, and reduce the discharge of gangue solid waste, the feasibility of its sorting was studied by means of coal quality characteristics, screening, flotation and sedimentation and rotary mudification experiments. The results indicate that the calorific value of the raw coal is 8 685.80 kJ/kg, which is a bituminous coal with high ash, low sulfur and low heat. For the raw coal of size class 50.0-0.5 mm, when the ash content of clean coal is required to be 12%,the δ±0.1 content of the combined natural and crushed grade is 32.87%,and the optional grade of raw coal is difficult to be separated. When the ash content of clean coal is required to be 20%,the δ±0.1 content of the combined natural and crushed grade is 41.08%,and the raw coal selectability grade is extremely difficult to be separated. For the raw coal of <0.5 mm size class, when the ash content of the clean coal is set at 20%,the δ±0.1 content of the combined natural and crushed grade is 35.96%,and the raw coal selectability grade is difficult to be separated. When the ash requirement of the clean coal is 12%,using three-product dense medium cyclone sorting and heavy media shallow slot sorter respectively, the yield of clean coal can be obtained as 5.31% and 2.56%,and the yield of medium coal is 21.74%. This study will provide guidance for the sorting and utilization of Haidaigou bottom coal, and provide important reference for the sorting and carbon extraction of other coal gangue with high carbon content.

    2023 S2 v.29 [Abstract][OnlineView][Download 1904K]
  • Independent research and application of complete coal preparation equipment

    ZHANG Bingxiang;Shendong Coal Group Washing Center;

    The vibrating screen used in the process of coal separation, processing and utilization is one of the important equipment for coal separation. Due to frequent failures in the long-term operation of the equipment, the use of the tiger carat riveter in the maintenance process is affected by the working conditions. The short mission life and high cost of the equipment hinder the high-quality development of the coal industry. Therefore, from the source, actively explore the improvement ideas to achieve intelligent wireless operation of the tiger carat riveter. With the rapid development of the coal mine industry, the comprehensive mechanization degree has improved, the production capacity has increased, and the use of belt conveyors has also increased. Due to the impact of the operating environment and operating conditions, belt fire accidents have occurred from time to time, which not only causes economic losses to the production enterprises, but also causes great danger to people. By reforming and designing the over-temperature protection tester and standardizing the use of the safety belt alarm device, the probability of safety accidents has been reduced, Provide help for high-quality and safe development of enterprises.

    2023 S2 v.29 [Abstract][OnlineView][Download 1919K]
  • Stimulation technology of coalbed methane well based on temporary plugging and directional fracturing and its application example

    YIN Zhongshan;Sichuan Institute of Geological Survey;Sichuan Key Laboratory of Shale Gas Evaluation and Exploitation;

    In order to apply temporary plugging and diverting fracturing to conventional and unconventional oil and gas exploration and development, the technology of fracture and in-layer diverting fracturing is often related to re-fracturing in oil and gas reservoir development. Based on the characteristics of thin, dispersed and multi-layer coal reservoirs in south Sichuan, the feasibility of using the soluble temporary plugging ball to implement the fracture-turning fracturing is studied, based on the principle of optimizing fracturing design simulation parameters and increasing fracturing scale, the formation of complex fracture network and the utilization of large reserves in the target zone can be realized. The results show that the fracturing technology of“Coal seam + floor mudstone, roof mudstone + coal seam combination, temporary plugging of joint, large amount of fluid and large amount of sand” has been successfully applied for the first time in LC1 well, the fracture length, fracture pattern and gas production effect of temporary plugging and diverting fracturing in LC1 well have achieved the expected goals. It provides technical support and important reference value for exploring high-efficiency reservoir reconstruction technology and realizing high-efficiency development of coalbed methane in Southwest China.

    2023 S2 v.29 [Abstract][OnlineView][Download 1856K]
  • Application of coal dust suppression technology based on aqueous media

    LI Peng;WANG Chenglong;ZHANG Moxin;CHN Energy Shendong Coal Separating Center;Information Technology Co.,Ltd.,China Coal Technology and Engingneering Group;

    Long term exposure to coal dust will lead to various lung diseases, such as pneumoconiosis(CWP), threatening the health of underground miners. Solution spraying and coal seam water injection are widely used to reduce the concentration of coal dust in underground mining.Coal dust control technology based on water medium was reviewed.The influencing factors of the dust control technology effect of water medium were analyzed. At the same time, the challenges and future research directions were discussed. In addition to improving the wettability of solution, it is suggested to study the solidification mechanism between dust particles and droplets. In addition, the formation method of spray field and the spatial distribution of droplets near the dust producing area should be further studied, which is of great significance for improving the droplet number density of dust removal spray.

    2023 S2 v.29 [Abstract][OnlineView][Download 1808K]
  • Key processing audio data intelligent identification archive management of coal preparation plant

    LI Tongpo;Washing Center of Shendong Coal Group,National Energy Investment Group co.,Ltd.;

    Project research purpose is to solve the problem of only the graphic data records in the production, operation and management of each coal preparation plant in Shendong Washing Center. There is a problem of managing the blank of key voice or other audio data. In recent years, new technologies and new devices have emerged one after another. Many digital devices(such as voice recorders) with audio recording and recording functions have appeared. Although certain recording functions were had, they cannot realize intelligent recognition of audio and processing of voice or other audio data were not realized. The processing function can only record and record the whole process, and it is not easy to retrieve and utilize the audio data. After systematically expounding the speech recognition technology, this paper proposes a set of intelligent processing and archiving management scheme based on speech recognition technology to realize the key audio data of the coal preparation plant. According to the peak and valley law of the audio signal, the audio signal is compared with the computer VB programming technology. Use computer audio collector to collect audio signals such as field device audio, personnel dialogue audio, telephone audio, walkie-talkie audio, broadcast audio, etc.,and apply VB programming to perform audio intelligent detection, intelligent recognition and intelligence on the collected voice or other audio data. After the data filtering and cleaning process is processed, the audio translation private cloud engine is triggered to perform audio translation semantic recognition, text and audio recording, and save data programs. Through practical application, it realizes intelligent resolution of effective voice or other audio data intelligent archive management functions. On the software, hardware composition, function and characteristics of the scheme was elaborated.

    2023 S2 v.29 [Abstract][OnlineView][Download 1921K]
  • Design of fire prevention and fire monitoring system in coal preparation plant

    DU Rui;Shangwan Coal Preparation Plant,CHN Energy Shendong Coal Preparation Center;

    Due to the particularity of production and operation, coal preparation plant is prone to fire, which has a great impact on the personal safety of employees and the economy of coal preparation plant. In order to improve the safety of coal preparation plant production, fire must be prevented. The causes and types of fire in coal preparation plant was analyzed, so as to better carry out targeted fire prevention and monitoring. Because of concealment characteristics of electrical fire, the design of the fire monitoring system was discussed, so as to better supervise and control the potential fire hazards in the coal preparation plant, and better guarantee the safety production of the coal preparation plant.

    2023 S2 v.29 [Abstract][OnlineView][Download 2001K]
  • Optimizing method and application of geological target area for increasing production in coalbed methane low production well area

    HAN Wenlong;WANG Yanbin;LI Yong;NI Xiaoming;WU Xiang;ZHAO Shihu;College of Civil and Transportation Engineering, Shenzhen University;College of Geoscience and Surveying Engineering,China University of Mining and Technology (Beijing);School of Energy Science and Engineering,Henan Polytechnic University;China United Coalbed Methane Corporation Limited;

    Activating a large number of low-production coalbed methane(CBM)wells is one of the key tasks to solve the problem of low CBM production in my country. Based on the control characteristics of various geological parameters on the development effect of CBM, a new understanding of reservoir parameters: production gas geological potential evaluation-reservoir structure feature partition-increasing production improvement geological target area selection method for increasing production improvement geological target area of low production well area of coalbed methane(“four-step” optimization method of stimulation improvement target area). By analyzing the key parameters of coal reservoirs that affect the development of coalbed methane, making full use of fracturing and drainage data, and combining drilling, logging, and laboratory testing data, a model for recognizing key geological parameters has been established. The multi-level fuzzy comprehensive evaluation method puts forward a low-yield well gas production potential evaluation index system. Based on the vertical combination characteristics of structure and coal structure, the reservoir structure feature zoning method is established. finally a set of low-yield coal-bed methane wells is formulated to increase production method for rebuilding the geological target area. Using the "four-step" optimization method, 42 low-yielding wells were selected in the south Shizhuang CBM block in the southern Qinshui Basin. After stimulation, the average gas production of a single well increased from 310 m~3/d to 960 m~3/d, and the current gas production maintains a trend of rising or stable gas production. Compared with the experimental wells implemented outside the target area, the single-well gas production increment and overall success rate have been greatly improved. This method points out the direction and provides strong geological support for the treatment and selection of coalbed methane low-production wells.

    2023 S2 v.29 [Abstract][OnlineView][Download 2537K]
  • Application of equipment on-line condition monitoring system in coal industry

    WANG Anjia;CHN Energy Shendong Coal Preparation Center;

    In the process of coal mine production, equipment failure will not only affect production efficiency, but also cause personal safety and production safety accidents. Therefore, it is necessary to adopt technical means for real-time monitoring of coal mine core equipment. The equipment on-line condition monitoring system is mainly applied to the monitoringand fault diagnosis of large machinery and electromechanical equipment in coal mineproduction. It mainly carries out real-time monitoring on the key parts of the equipment, such as gearbox, main shaft and generator bearing. The monitoring parameters include vibration, wind speed and oil temperature.The signals of equipment vibration, wind speed and temperature were analyzed, and equipment operation was real-time monitoring. The fault type of equipment was determined combined with equipment fault diagnosis database to realize equipment fault diagnosis. The application of equipment on-line condition monitoring system not only improves the working efficiency of personnel, but also improves the practical life of equipment.

    2023 S2 v.29 [Abstract][OnlineView][Download 2106K]
  • Video location method of production personnel in coal preparation plant based on digital twin

    XIONG Chaoyuan;ZHANG You;HU Yuxi;Halagou Coal Preparation Plant,CHN Energy Shendong Coal Preparation Center;China Coal Technology & Engineering Group Information Technology Co.,Ltd.;

    In order to improve the real-time positioning effect of safety video for production personnel, aiming at the problems of low definition of contour edge and difficult segmentation between safety area and production personnel contour, a real-time positioning method of safety video for production personnel in coal preparation plant based on three-dimensional digital twins was studied. The data layer collects the real-time video data of the coal preparation plant area by calling various sensors in the physical layer, and processes the real-time video data for cleaning and value-added processing. The virtual layer uses the virtual real mapping method to process the effective data, completes the virtual real interaction between the physical space and the virtual space, obtains the real-time twin data, and establishes the three-dimensional digital twin model of the real-time coal preparation plant. The service layer uses the pyramid scene to analyze the network semantic segmentation model, processes the three-dimensional digital twin model, obtains the contour edge of the safety area and the production personnel, and completes the real-time positioning of the production personnel safety video according to the intersection relationship between the two contour edges. The experimental results show that this method can effectively construct the three-dimensional digital twin model of the coal preparation plant, effectively segment the safety area and the contour of the production personnel, and extract the contour edge. This method can effectively detect the dangerous behaviors of production personnel and complete the real-time positioning of safety video of production personnel.

    2023 S2 v.29 [Abstract][OnlineView][Download 2030K]
  • Intelligent construction of coal preparation plant to help the safety management

    DU Rui;Shangwan Coal Preparation Plant, Washing Center of Guoneng Shendong Coal Group Co., Ltd.;

    With the release of made in China 2025 and the rapid development of modern communication technology, computer network technology and intelligent equipment upgrading and transformation, and all industries across the country are marching towards the direction of intelligent construction. With the help of intelligent projects, the safety production efficiency will be improved in an all-round way, and the product quality will also be significantly improved, and the refined safety production and management will be realized. The article first discusses the safety problems existing in the coal preparation plant, and then analyzes the specific performance of the intelligent project of the coal preparation plant to help the safety management, as well as the importance of the safety management of the intelligent coal preparation plant. Through the intelligent creation of the coal preparation plant, The harmony and unity of human, machine, environment and management is achieved, which provides a sufficient guarantee for the safety management of the coal preparation plant.

    2023 S2 v.29 [Abstract][OnlineView][Download 2201K]
  • Analysis on the approaches of efficient and clean utilization of China′s coal resources under the new situation

    PAN Yuejun;Shendong Coal Distribution Center,CHN Energy;

    There is always waste of resources in coal mining enterprises, and coal, as a primary energy, is contrary to the current concepts of green and energy conservation. In order to adapt to the development trend of the new era, improving the utilization rate of coal and creating a green, clean and efficient application development model become the focus. In recent years, with the continuous support of technological research activities, various technologies have become increasingly mature, which also provides opportunities for coal enterprises to transform to efficient utilization. Especially under the guidance of the energy development strategy, the efficient and clean utilization of coal has been further implemented. Based on the analysis of the relevant information of the State Energy Group Shendong Coal Group Co., Ltd., the problems faced by the efficient and clean utilization of coal resources were summarized. Two new ways of utilization were summarized, which were the on-line analysis equipment of coal quality based on high-energy pulsed laser multi-energy spectrum and the safe and efficient injection technology of oxygen-enriched full bituminous coal in ironmaking blast furnace. This study can provide more reference for realizing green development in the coal industry.

    2023 S2 v.29 [Abstract][OnlineView][Download 1810K]
  • Study on the internal power of coal mine enterprises to stimulate the safety management of all staff

    WANG Yanbing;FENG Lezhen;Distribution Center,CHN Energy Shendong Coal Group Co.,Ltd.;Mathematics Group,Ordos No.3 Middle School;

    Using the principles of management, economics and human resource management, combined with the actual situation of safety management, a few key employees according to the three seven rules was put forward,a complete set of safety management incentive system was summarized. It is to comprehensively use positive and negative incentives, material incentives and spiritual incentives, and consider the age differences, cultural differences, position differences and other differences of different personnel in the enterprise. The systematic analysis of incentives should be carried out according to the needs of different people. At the same time, the mine should establish its corresponding corporate culture and system, complement each other, and ensure the full play of the efficiency of the incentive system.

    2023 S2 v.29 [Abstract][OnlineView][Download 1839K]
  • Analysis of industrialization, air quality and carbon emission from the perspective of high quality

    LI Tianxin;GAO Shan;HAN Yangwen;XU Shuiyang;CHENG Shikun;WANG Xu;School of Energy and Environmental Engineering Beijing University of science and technology;Beijing Key Laboratory of recycling typical industrial pollutants;

    With the acceleration of China′s industrialization development process, the problem of atmospheric environmental pollution has become increasingly prominent, which has seriously affected the process of China′s high-quality development. Therefore, based on the data of 31 provinces from 2003 to 2019,the Pearson correlation coefficient was used to analyze the correlation between industrialization, air quality and carbon emission and the ratio method was used to quantify the high-quality development standard. On this basis, the migration trajectory between the three was analyzed based on the center of gravity method. The results indicate that the areas with strong negative correlation between industrialization and air quality show a clean development model, and the highest correlation degree can reach 0.994. There is a strong negative correlation between industrialization and carbon emission, building an energy-saving development model, with a maximum correlation of 0.932. Areas with strong positive correlation between air quality and carbon emissions illustrate a coordinated development model of reducing pollution and carbon, with the highest correlation of 0.989. The quantitative analysis of the ratio reveals that the high-quality development standards are: industrialization ≥ 122.61,air quality ≤ 5.76 and carbon emission ≤ 154.94. It can be seen from the law of spatial change that industrialization and air quality are migrating synchronously from northwest to Southeast, while the migration trajectory of carbon emission is just the opposite, which shows that the low-quality industrialization is the main cause of high emission. Therefore, the transformation of development mode in high emission areas is the primary task. The results can provide differentiated management and control suggestions and reference for the implementation of industrial air pollution control and carbon reduction strategy in China, so as to promote the high-quality development of industrialization in all regions.

    2023 S2 v.29 [Abstract][OnlineView][Download 2570K]
  • Research on positioning and economy of emergency standby power supply based on dual carbon background

    ZHANG Jian;ZHANG Jianyun;HU Zhenguang;GONG Jiayou;ZHAO Haijun;ZHANG Wanlin;CHN Energy Technology & Economics Research Institute;

    Emergency standby power supply is a necessary measure to implement the carbon peak and carbon neutralization work plan, and an important measure to promote the optimization and upgrading of the coal power industry. Its operation status can be divided into long-term shutdown, hot standby and operation. Since 2019,the power load of the whole society has repeatedly reached new highs in summer, and the power system has also experienced extreme tests of peak summer, energy consumption dual control policy and large-scale fluctuations in new energy. During the peak period of electricity in the whole society, sufficient power can be provided by the operating power supply, and thermal power units undertake a large number of peak shaving and frequency modulation services. The load rate of grid connected coal-fired power units is relatively low. In 2021,the utilization hours of coal-fired power units will be 4 448 h, and the peak capacity will be borne by the grid connected units. This situation leads to the long-term shutdown of the emergency standby power supply, which can not solve the problem of temporary power shortage in the power system. When the new energy power generation plummeted and the normal standby coal-fired power unit could not be started on time, the emergency start-up time of the long-term shutdown emergency standby power supply was longer, which could not reach the peak and the pain of rapid load in a short time. At the economic level, the long-term shutdown of the emergency standby power supply will also lead to accelerated corrosion of the cooling water system, bearings, flue, heating surface,heat exchanger,drain pipe and other parts. The maintenance and overhaul workload is generally no less than the normal operation of the unit. The substantial increase in the operation and maintenance workload will lead to high operation and maintenance costs. The operation and maintenance cost of a 300 MW unit due for service during the emergency standby period is estimated to be about 70 million630 thousand yuan/a. With the extension of the standby time,the cost will increase. Without calculating the depreciation of equipment,assuming that the costs and benefits during the operation period are offset,the 300 MW emergency standby power supply operates 168 h a year,the load rate is 80%,and the emergency standby cost is about 1.75 yuan/kWh. Compared with other regulation methods,it has no advantage. The high standby cost and long emergency start-up time of coal power emergency standby power supply seriously affect its due emergency standby function.

    2023 S2 v.29 [Abstract][OnlineView][Download 1803K]
  • Application of digital intelligence system in Heitangou loading monitoring station

    JIN Shuqiang;FAN Jichang;GU Hongwei;China Energy Coal Trading Group Limited;

    In order to effectively reduce the operational safety risks of on-site inspection and supervision of coal loading station personnel, Heitangou loading monitoring station has been upgraded with digital intelligence, adding the functions of foreign object recognition, real-time monitoring of coal temperature, car number identification, heavy car bias overload warning, etc.,and assembling vehicle-mounted mobile car sampler, which reduces the labor intensity of workers and realizes the whole process monitoring of coal loading, car loading and sampling.After the transformation, mechanized sampling further improves the representativeness of samples, and the transformation of coal quantity and quality management at the loading end is successful. The application of digital intelligence visualization in the whole chain has improved the management level of the bulk platform, and has a significant effect of cost reduction and efficiency increase, which is of great significance for promotion.

    2023 S2 v.29 [Abstract][OnlineView][Download 2168K]
  • Lighting energy saving technology in coal preparation plant

    LI Xinmei;LIU Shangwei;HOU Xiangzhen;Guoneng Shendong Coal Group Co., Ltd.;Shandong Huading Weiye Energy Technology Co.,Ltd.;

    The energy and resource consumption of the coal preparation plantis is very large, the lighting system is one of the key components, and the demand for power resources is relatively large. In order to ensure the green and energy-saving effect of the lighting system and improve the economy of the coal preparation plant, the lighting energy-saving technology in the coal preparation plant was studied. The improvement method of lighting energy-saving system in coal preparation plant was analyzed. The design method of optimizing lighting energy saving in coal preparation plant was put forward from the aspects of using high-efficiency light source, ensuring lighting quality and ensuring the rationality of control mode. Based on the requirements of lamp selection, the application of lighting energy-saving technology in coal preparation plant and intelligent lighting energy-saving control system, the specific application of lighting energy-saving technology in coal preparation plant was analyzed. The research results are of great significance to improve the management and utilization efficiency of lighting system, and achieve the development goals of energy and resources conservation.

    2023 S2 v.29 [Abstract][OnlineView][Download 1791K]
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