2023年01期目次

  • Comprehensive assessment of development path of carbon capture technology based on AHP-TOPSIS method

    LIU Shuang;SONG Xuehang;SHANG Li;WANG Baodeng;SHEN Qun;XIONG Rihua;SUN Nannan;WEI Wei;Shanghai Advanced Research Institute,Chinese Academy of Sciences;University of Chinese Academy of Sciences;National Institute of Clean-and-Low-Carbon Energy,CHN Energy;

    Carbon capture, utilization, and storage(CCUS) offers an important option to achieve carbon neutrality, however, cost-ineffectiveness hinders the widespread application of CCUS. Among the technical chain of CCUS, carbon capture is the major contributor to the entire cost of CCUS. Recently, the development and demonstration of various carbon capture technologies have received extensive attention, but their overall maturity is still low, and future development path is still unclear. Based on the analytic hierarchy process and technique for order preference by similarity to ideal solution, a set of new methodology was established for the evaluation of carbon capture technology, and several typical carbon capture technologies were comprehensively analyzed from aspects including technology, low carbon, economics and safety. It is found that the deployment of carbon capture technology is mainly affected by their low carbon features at the present stage, and the composite amine absorption method possesses the greatest potential at present. However, with the continuous adjustment of energy and industrial structure in the future, the application scenarios of various carbon capture technologies and the factors affecting their deployment potential will change, and the economic features will become the key to determine the market penetration rate. Therefore, it is expected that pressure swing adsorption, composite amine absorption, and calcium looping will play a relatively important role in the future. By combining quantitative analysis with expert opinions, the evaluation results of this paper may provide scientific and objective guidance to the research and application of carbon capture technologies.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 12638K]

  • Deep fluidized coal mining and its prospect under the target of carbon peak and carbon neutralization

    YU Haiyang;XU Yongbin;CHEN Zhiming;LIU Zelin;WANG Yang;CHENG Shiqing;WU Yuxin;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum (Beijing);Xinjiang Oilfield Branch Company;Department of Energy and Power Engineering,Tsinghua University;

    In order to actively respond to global climate change, China has set a "carbon peaking by 2030 and carbon neutrality by 2060" goal. The energy structure of China decides that coal is the main consumption energy, and the situation can not be changed in the short term. In order to achieve the goal of carbon peaking and carbon neutrality, the coal industry needs to innovate from both technical and theoretical aspects. Therefore, based on the idea of underground coal gasification, and three ways of deep coal fluidization production were summarized, namely gasification, pyrolysis and biological dissolution. Among them, the coal underground gasification technology was mainly reviewed, including the development history, gasification process and factors affecting the stability of some typical coal underground gasification projects at home and abroad, and the reasons why the coal underground gasification technology has not formed industrial production were briefly analyzed. In addition, the injection and production technology between multistage fractured horizontal well and well seam in petroleum industry is introduced into deep underground coal fluidization mining. The deep underground coal fluidization mining was realized by injecting gasifier and adding heating device. Based on the injection and production technology between horizontal wells, the application prospect and scope of a new well type in underground coal gasification, underground pyrolysis and underground bio-dissolution mining were discussed. Compared with the traditional underground gasification process, the injection and production technology between horizontal well and well seam has the advantages of saving mining costs, improving economic benefits, enlarging gasification reaction area and improving the spread range. In addition, the new energy technology can also be used to generate electricity and heat, which can reduce carbon emissions to a certain extent and promote the realization of the national "double carbon" goal. Finally, combined with the current situation of deep coal fluidization development, the existing problems were analyzed and some suggestions were put forward for the future development of deep coal underground gasification industry.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 30513K]

  • Molecular structure characteristics of spinnable pitch molecules synthesized by the methods of chlorination-dechlorination and thermal polycondensation derived from coal liquefaction residue

    LIU Jinchang;LIU Qin;SHEN Chenyang;LI Yaping;AN Xiaoya;XIE Qiang;LIANG Dingcheng;School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing;

    The property of spinnable pitch is a significant factor in determining continuously and stably industrial production of pitch-based carbon fiber, and it also affects largely the performance of final carbon fiber. Generally, the synthesis method is an important means to control the property of spinning pitch. Compared to the method of thermal polycondensation, chlorination-dechlorination method can controllably synthesize spinnable pitch from the molecular dimension to improve the spinnability. However, there are few reports on the differences in the molecular structure characteristics of spinnable pitches synthesized by thermal polycondensation and chlorination-dechlorination methods, respectively. In this work, the molecular composition and structure of the spinnable pitches were determined by elemental analysis, Fourier transforms infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI TOF-MS), and solid-state nuclear magnetic resonance(~(13)C-NMR). The average molecular model method was used to construct the molecular model of spinning pitch. The results show that the spinnable pitch synthesized by the chlorination-dechlorination method has higher carbon content and the characteristic peaks is shown at 1 490 cm~(-1) and 696 cm~(-1) and XPS C 1s spectra at 287.1 eV in FTIR spectra. From MALDI TOF-MS and ~(13)C-NMR analysis, spinnable pitch synthesized by chlorination-dechlorination has a higher polycondensed degree, molecular weight, and carbon aromaticity, with the average molecular weight of 857, and the carbon aromaticity of 0.87. The molecular structure of the spinnable pitch tends to be more linear in the one-dimensional direction. According to the results of characterization analysis, the molecular models of spinnable pitch synthesized by chlorination-dechlorination and thermal polycondensation were established using the average molecular model proposed by Shoolery-Budde.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 7702K]

  • Synthesis and molecular structure analysis of 2-methyl-6-acetylnaphthalene via the acylation of 2-methylnaphthalene

    XU Jingwen;WANG Yuan;SHI Zhiyao;HU Haoquan;JIN Lijun;Institute of Coal Chemical Engineering,School of Chemical Engineering,Dalian University of Technology;

    2-methyl-6-acylnaphthalene(2,6-MAN) is one of the most important precursors(such as polyethylene naphthalate PEN) for polyester materials with high performances, and its highly selective synthesis is of great significance.Using 2-methylnaphthalene(2-MN) as the raw material, acetyl chloride(AC) as acylating agent and aluminum trichloride(AlCl_3) as catalyst, the effect of the reactants ratio, reaction time, reaction temperature and addition temperature on the acylation process was studied by orthogonal experiments. The acylation products were further purified by recrystallization. The effect of solvent amount and cooling rate of solution on the product purity was investigated. The results from the analyses of GC-MS, FT-IR, 1D-NMR and 2D-NMR show that the main component of acylation products is identified to be 2,6-MAN containing C~6-substituted acetyl.The results of orthogonal experiments show that the ratio of reactants has the most influence on the product yield. The insufficiency of acylating agent and catalyst causes the yield decrease. The reaction temperature shows the most significant effect on the 2,6-MAN purity. When the ratio of n(2-MN)/n(AC)/n(AlCl_3) is 1.00/1.20/1.45, the reaction temperature is 25 ℃, the reaction time is 4 h, and the addition temperature is-5 ℃ to-2 ℃,the resultant products yield can reach 90.93%, along with the purity of 2,6-MAN being 76.32%. When using methanol aqueous solution as solvent to purify the acylation product, the results show that high ratio of solvent/acylation product and slow cooling of the solution can improve the purity of the target product. When the mass ratio of methanol aqueous solution to acylation product is 5/1 and the slow cooling along with addition of crystal seeds is utilized, the resultant product with 2,6-MAN purity is above 98%, which can meet the oxidation need of 2,6-MAN in industry.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 13388K]

  • Numerical simulation of waste heat utilization process after in-situ pyrolysis of tar-rich coal

    CHEN Meijing;QI Bowen;WANG Chang′an;MAO Qisen;CHE Defu;State Key Laboratory of Multiphase Flow in Power Engineering,Xi′an Jiaotong University;

    Tar-rich coal, as a recognized distinctive type of coal resource, is a crucial strategic energy in China with enormous reserves. In-situ pyrolysis of tar-rich coal is a new technology that abandons traditional coal mining and directly extracts oil from underground pyrolysis.Previous studies on in-situ gas injection heating mainly focused on the exploitation and utilization of oil shale. Although the residual heat from block pyrolysis has significant economic benefits, the process of utilizing waste heat has received little attention.A two-dimensional large-scale model of the semi-coking area cooling of tar-rich coal was built in order to analyze the influence rules of cooling medium type, inlet velocity and temperature of cooling medium, initial temperature of semi-coke area, well layout, number of horizontal cracks, heating duration and inlet velocity of heating medium on the waste heat utilization process. The results demonstrate that the flow velocity of the cooling medium has a limited effect on the cooling effect of the semi-coking area. The contribution of the heating medium velocity to the average temperature rise is limited.CO_2 as the cooling medium is favorable for the cooling of semi-coking area when compared to N_2 and water vapor. The temperature uniformity of the semi-coke layer and the cooling efficiency can be improved by increasing the number of gas injection wells, but the location of gas injection wells has essentially little impact on semi-coking area cooling.The double horizontal fracture arrangement is sufficient to meet the requirements of effective cooling. By optimizing the parameters of the initial state of semi-coking area cooling, it is helpful to understand the temperature variation law of the cooling process, improve the utilization efficiency of waste heat, and provide a theoretical foundation for the entire process of in-situ thermal injection mining of tar-rich coal.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 44191K]

  • Integrated system of indirect coal liquefaction and IGFC with near zero CO2 emission

    YANG Zhanqi;XU Ming;ZHANG Lele;DU Nianyou;GONG Siqi;ZHANG Jihua;YANG Xia;LI Chufu;Coal to Oil Branch Company,Ningxia Coal Industry Co.,Ltd.,CHN Energy;National Institute of Clean-and-Low-Carbon Energy;

    Under the background of carbon neutralization, indirect coal liquefaction is facing huge pressure of carbon emission reduction. On the basis of advanced indirect coal liquefaction technology, an integrated system of indirect coal liquefaction and integrated gasification fuel cell(IGFC) with near zero CO_2 emissions has been built. Through high-temperature fuel cells, coal-based syngas and Fischer-Tropsch synthesis tail gas can be directly used for efficient power generation, replacing the traditional self-contained power station to supply power and heat for the indirect coal liquefaction process. At the same time, CO_2 enrichment of tail gas is realized, reducing the difficulty of CO_2 capture. For the integrated system, the IGFC technical research progress was introduced, and the integrated demonstration of IGFC technology was carried out. Based on the indirect coal liquefaction unit, the first megawatt level IGFC test base in China was built, and the first 100 kW level IGFC test demonstration system with near zero CO_2 emissions was developed, realizing continuous and stable operation. The fuel cell system generated 101.7 kW of power, with 53.2% of power generation efficiency and 98.6% of CO_(2 ) capture ratio.The feasibility of the integrated system is verified.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 5640K]

  • Flow field hydrodynamic characteristics and intensification mechanism of bubble column reactor for direct coal liquefaction process

    HUANG Sheng;QIAN Jiashu;ZHANG Yuanlin;WU Shiyong;CHEN Jianpei;WU Youqing;Department of Energy Chemical Engineering,School of Resource and Environmental Engineeing, East China University of Science and Technology;State Key Laboratory of Chemical Engineering,School of Resource and Environmental Engineeing, East China University of Science and Technology;

    A new type of resistance internal with radial expansion was developed to overcome the major problems in large bubbling bed reactor, such as enhanced re-mixing, uneven distribution of flow field and low mass transfer efficiency, which could affect the stable and efficient operation of the reactor and the safety of working conditions. The effect of resistance internal on bubble aggregation and fragmentation behavior was explored in cold model test platform, and the flow field flow characteristics of different combinations of resistance internals in a large reactor were investigated, and the flow field enhancement effect of resistance internal combinations in the industrial reactor amplification process was explored. The results show that the turbulent vortex scale is reduced and the bubble fragmentation probability is increased after the resistance internal is set in the cold model test device of bubble column reactor, and the average diameter of the bubble population decreases from 13.48-24.38 mm to 9.40-20.38 mm after different bubble populations pass through the resistance internal, and the surface area is increased by 8.5%-71.9%.The installation of the resistance internal can improve the uniformity of local gas holdup and liquid velocity distribution in the reactor, and the axial influence range of the flow field can be expanded by increasing the number of resistance internal layers. Increasing the diameter of the resistance internal is beneficial to reduce the difference of the local liquid velocity in each height plane and improve the uniformity of the radial distribution of the local gas holdup. The difference of the central liquid velocity in different height planes is reduced from 0.6 mm/s to 0.3 mm/s, and the variance of the local gas holdup in the same height plane can be reduced to 15% of that without the resistance internal. The radial range of fluid flow around the reactor is expanded during the process of reactor amplification, and the uniformity of local gas holdup and liquid velocity distribution is further reduced. The variance of local gas holdup in the same height plane can be reduced to 7% of that without the resistance internal, and the difference of local liquid velocity is reduced from 1.3-2.7 mm/s to 1.0-1.1 mm/s after setting the resistance internal combination. When a 1/4 times tower diameter distributor is set and the resistance internal combination is set in the way of installation interval :distributor diameter=7∶1, the flow field strengthening effect is better.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 35745K]

  • Effect of iron salt precursor on the Fe-Ti catalyst and their de-NOx performance

    ZHANG Jiahui;CAI Sixiang;QIU Xuewu;JIANG Hong;School of Materials Science and Engineering,Hainan University;Hainan Special Glass Laboratory,Hainan University;State Key Laboratory of Marine Resources Utilization of the South China Sea,Hainan University;Sinopec Hainan Refining & Chemical Limited Company;

    A series of iron-titanium mixedoxides de-NO_x catalysts were prepared by replacing the Fe(NO_3)_3 with FeSO_4. Among this series of catalysts, the Fe_(0.5)Fe_(0.5)TiO_y catalyst shows the advantages of high stability, water-sulfur tolerance, excellent low-temperature activity and catalytics electivity. The catalysts were characterized by X-ray diffraction(XRD), Raman spectroscopy(Raman), specific surface area test(BET),programmed temperature rise method(H_2-TPR, NH_3-TPD, O_2-TPD), X-ray photoelectron spectroscopy(XPS) and In situ infrared(In situ DRIFTs). The results show that the Fe_(0.5)Fe_(0.5)TiO_y catalyst has a larger specific surface area(65.056 7 m~2/g), more surface reducible species, more acid sites and higher surface active oxygen concentration. Additionally, it is determined that the NH_3-SCR reaction process on Fe_(0.5)Fe_(0.5)TiO_y catalyst mainly follows the E-R mechanism.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 16955K]

  • Research progress on removal of flue gas pollutants by activated coke

    WEN Chang;WEN Wuhao;WANG Dapeng;JING Zhenqi;LIU Qian;XU Mingtao;ZHU Guangyue;State Key Laboratory of Coal Combustion,School of Energy and Power Engineering,Huazhong University of Science and Technology;Urban Environmental Engineering Technology Co.,Ltd.;School of Safety Science and Emergency Management,Wuhan University of Technology;

    Activated coke is an efficient and low-cost adsorbent for purifying flue gas pollutants with good crushing strength and renewable properties, which can use in power plants and other industries to remove pollutants from flue gas. It is the core material of dry flue gas purification technology, which can meet the development requirements of green economy and circular economy of our country. In this paper, the research progress of activated coke applied in flue gas pollutant removal was reviewed, the preparation, activation, modification, characterization and engineering application of activated coke were introduced, and the removal mechanism of several pollutants(SO_2, NO_x, Hg~0, VOCs) on activated coke was summarized. The related factors affecting the adsorption properties of activated coke and the research results of recycling process of waste activated coke were summarized. At present, activated coke can be prepared by mainly physical activation and chemical activation. Physical activation mainly uses water vapor and other gases under high temperature conditions to make activated coke have a porous structure, while chemical activation is mainly through acid, alkali, salt solutions to impregnate the activated coke, optimize the pore structure of activated coke, enrich functional groups on the surface, provide more adsorption sites for activated coke, in order to improve the ability of activated coke to remove flue gas pollutants. The pollutants have undergone physical and chemical adsorption processes on activated coke in the process of activated coke adsorption of pollutants. Some pollutants are directly physically attached onto the surface of activated coke, while some pollutants will be affected by adsorption conditions and functional groups of activated coke, and chemical reactions will occur at the adsorption site and be converted into other recyclable or harmless substances. Among them, SO_2 in flue gas is usually converted to H_2SO_4, NO_x is easily catalytic converted to N_2, Hg~0 can be converted to HgO or HgSO_4, and VOCs will eventually be converted to CO_2 and H_2O. The activated coke can complete the removal of flue gas pollutants through a series of adsorption and transformation processes. In order to further improve the engineering application capacity of activated coke, the adsorbed activated coke can also be reused through washing, heating, microwave and other ways. The improvement in the cyclic adsorption performance of activated coke by the conditions and methods of regeneration have been studied extensively. As the adsorption conditions of activated coke(adsorption temperature, flue gas components, etc.) and other influencing factors are gradually in-depth studied, the efficiency of pollutant removal of activated coke has been greatly improved, and the better adsorption performance of activated coke can reach more than 90%. In addition, with the preparation process of activated coke becomes gradually mature, activated coke has a better synergistic adsorption effect on pollutants, and has been used to a certain extent. The engineering application of activated coke at home and abroad was also summarized, and some problems and prospects of this technology were put forward, so as to provide reference for the research and application of activated coke in the future.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 8392K]

  • Experimental study on combustion pollutant emission and ash fusibility of blended fuel of semi-coke and straw

    HAN Kuihua;WU Pengkui;LIU Wenyang;WANG Wei;School of Energy and Power Engineering,Shandong University;Shandong Engineering Laboratory for High-efficiency Energy Conservation and Energy Storage Technology & Equipment,Shandong University;Weifang Botai Energy Technology Co.,Ltd.;

    Semi-coke has the advantages of high calorific value, low ash content, and low sulfur content, but low volatile content and high ignition temperature. Straw has low calorific value, high volatile content and low ignition temperature. The ignition characteristics between the semi-coke and straw are complementary. In order to investigate the emissionsof sulfur oxides, nitrogen oxides and ash melting performance of semi-coke mixed with biomass fuel combustion, the fixed bed experimental system was used to study three kinds of semi-coke from different regions, wheat straw, corn straw and the mixed fuel pollutant emission characteristics respectively, and the influence of mixing proportion and combustion temperature on pollutant discharge, and the ash melting performance was analyzed by the ash fusion analyzer. The results show that the release of sulfur oxide and nitrogen oxide from the mixed fuel is related to the mixing conditions, and the composition of raw materials and combustion process affect the pollutant release characteristics. When 20%-30% corn stalk is mixed into the fuel, the mixed fuel shows a good sulfur fixation effect, and the nitrogen release rate is about 0.04%. Sulfur precipitation is significantly promoted by raising the combustion temperature. When the combustion temperature is lower than 1 000 ℃, the mixed fuel of Fugu semi-coke and corn stalk have good self-sulfur fixation characteristics, and the nitrogen release rate is lower than 0.02%. In addition, the ash melting characteristic temperature of the mixed fuel is between the temperature of original semi-coke and corn stalk, which has a certain relationship with the mixing ratio. The anti-slagging property of semi-coke is significantly better than that of corn stalk, which is helpful to improve the slagging property of straw by mixing. The results of this study provide theoretical reference for clean utilization of semi-coke and biomass.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 20866K]

  • Combustion characteristics and kinetic analysis of gasified fine slag blended with coal and biomass

    SUN Xiaohui;YAN Jiqing;FANG Mengxiang;WANG Qinhui;KUANG Jianping;State Key Laboratory of Clean Energy Utilization,Zhejiang University;Qingshanhu Energy Research Base,Zhejiang University;Ningxia Shenyao Technology Co.,Ltd.;

    Gasification fine slag is mainly stacked and landfilled at present, and the pressure of environmental protection is high. How to efficiently utilize gasification fine slag with low calorific value is a hotspot at present. The total amount of the two kinds of gasification fine slag discharged from the gasification process of methanol synthesis and kerosene is large, which is difficult to dispose. Through particle size analysis and SEM observation of two kinds of gasification fine slag, it is found that the particle size of gasification fine slag is small, most of which is less than 100 μm. The structure of gasification fine slag is broken, consisting of many spherical particles formed by melt polymerization and irregular pores. Co-firing is an effective method to use low calorific value fuels. The gasification slag was mixed with coal and biomass in different proportions to analyze the combustion characteristics, and the Coats-Refern method was used to analyze the kinetic characteristics. It is found that cofiring of gasification fine slag with coal and biomass can greatly improve the combustibility of gasification fine slag and reduce the activation energy for combustion. The activation energy of methanol slag and kerosene slag is 105.10 kJ/mol and 100.80 kJ/mol respectively. When the proportion of gasification fine slag is 30% after mixed combustion of methanol residue, kerosene residue and coal, the comprehensive combustion characteristic index is the highest, which is 23.64×10~8 and 25.96×10~8 respectively. Meanwhile, the activation energy is the lowest, which is 89.46 and 83.76 kJ/mol respectively. The gasification fine slag con-tains abundant pore structure. A certain proportion of gasification fine slag mixed with coal can increase the contact area between combustible materials and air, facilitate gas adsorption and diffusion, shorten the time to reach the maximum combustion rate, and advance the maximum combustion intensity. The activation energy of methanol slag and kerosene slag cofiring with biomass is the lowest when the proportion of gasification fine slag is 30%, which is 72.14 and 69.59 kJ/mol respectively. The combustion temperature of biomass is lower than that of gasification fine slag, which can preheat the combustion process of gasification fine slag and significantly reduce the activation energy required for fixed carbon combustion of it.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 33365K]

  • Mechanism of covalent bond depolymerization of coal activated at medium temperature

    WANG Mingyue;ZHANG Siyuan;ZHOU Li;REN Qiangqiang;Institute of Engineering Thermalphysics,China Academy of Sciences;University of ChineseAcademy of Sciences;

    In order to study the microstructure changes of hot semi-coke activated by pulverized coal under different atmospheres and temperatures, Raman spectroscopy was used to characterize the carbon frame structure of coal coke, X-ray photoelectron spectroscopy(XPS) was used to detect the surface functional groups of C and O, and solid state ~(13)C nuclear magnetic resonance spectroscopy(~(13)C-NMR) was used to characterize the carbon covalent bond. The three measurement methods were verified with each other to improve the reliability of the results, and the chemical structure of semi-coke was characterized from the microscopic level. The influence of temperature and atmosphere on the chemical structure and surface functional group evolution of coal coke in the mesothermal activation reaction was analyzed, and the mechanism of mesothermal activation was discussed on this basis. The results show that the activity of char at 600-900 ℃ can be significantly enhanced by both CO_2 and water vapor, which may be caused by the combination of gas molecules and coal coke molecules to form carbonyl or carboxyl groups. Under the influence of carbonyl or carboxyl molecules, the carbon bonds connected are weakened and broken accordingly, thus destroying the aromatic ring and generating new active sites to enhance the reaction activity of coal. After CO_2 activation at 800 ℃ or water vapor at 900 ℃, the number of active sites of semi-coke are increased by more than two times, respectively, and the proportions of carbonyl and carboxyl groups each increase from 18% to 32% and 34%. However, aliphatic carbons bonded to oxygen increase from 0.02 to 0.11 due to moderate CO_2 activation, and the ratio of aromatic bridge carbon to aromatic peripheral carbon is 0.01 after steam activation, which is significantly lower than that of semi-coke after N_2 pyrolysis. The mesophilic activation reaction of pulverized coal mainly forms more active sites through the formation of carbonyl and carboxyl group to destroys the aromatic structure. However, the products formed by the two groups are different due to their different scopes and rate-determining steps. CO_2 mainly plays the activation effect by transforming the sp~2 structure of coke edge into the carbon structure rich in sp~3 hybridization, while water vapor can be activated by inhibiting the graphitization process in the layer.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 21196K]

  • FGD combined desulfurization test based on multiple economic factors

    WANG Pengcheng;GAO Mingkai;LI Lifeng;JIA Yangjie;CHENG Fangqin;YANG Fengling;Shanxi Hepo Power Generation Co.,Ltd.;Institute of Resources and Environment Engineering,Shanxi University;State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste Resources;

    Under the restriction of ultra-low emission of flue gas pollutants, the large-scale circulating fluidized bed generator sets can not meet the requirements by desulfurization in the furnace lonely, and need to use a flue gas desulfurization system outside the furnace. The organic matching of the two desulfurization can reduce the comprehensive desulfurization cost. The optimal desulfurization distribution ratio of two-stage combined deep desulfurization in the operation process of power plant can achieve the lowest desulfurization cost under the emission standard. According to a variety of cost factors, a technical and economic calculation model was established to analyze the influence of different furnace calcium-sulfur ratios on the desulfurization distribution ratio and main cost factors, and explore the impact of different limestone prices and plant electricity prices on the comprehensive desulfurization cost. The results show that when the ratio of calcium to sulfur in the furnace is 1.0, 1.1-1.5, 1.6, 1.7-2.1, the best desulfurization shares in the furnace are 70%, 60%, 85% and 80%, respectively. Furnace desulfurization has great influence on boiler thermal efficiency, and the higher the molar ratio of calcium to sulfur, the greater the influence. When the ratio of calcium to sulfur exceeds 2.0, the heat loss of in-furnace desulfurization can reduce boiler thermal efficiency. The main cost factors of in-furnace desulfurization are limestone powder cost and operation power consumption cost, and the main cost factors of limestone/gypsum wet flue gas desulfurization are limestone slurry cost and absorption tower operation power consumption cost, which have obvious changes with different desulfurization distribution ratio. Different limestone prices and factory electricity prices have different optimal desulfurization distribution shares under different conditions of calcium-sulfur ratio in the furnace.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 25078K]

  • Effect of low-temperatue torrefaction and upgrading on the ignition and combustion characteristics of lignite

    DONG Kun;HU Zhongfa;ZHOU Bofei;ZHOU Yuegui;WANG Xuebin;CHEN Guanyi;LEI Tingzhou;New Energy Technology Research Institute Co.,Ltd.,CHN Energy;School of Environmental Science and Engineering,Tianjin University;School of Mechanical Engineering,Shanghai Jiao Tong University;School of Energy and Power Engineering,Xi′an Jiaotong University;

    High moisture and volatile content of lignite are not conducive to transportation and storage, and can reduce boiler combustion efficiency. As a common technology for lignite upgrading, low-temperature torrefaction and upgrading can effectively reduce moisture in fuel and improve fuel quality, significantly change the combustion characteristics of lignite. In the diffusion-flamelet-based Hencken burner experimental facility, the effect of torrefaction temperature(200, 250 and 300 ℃) on the ignition and combustion characteristics of lignite were carried out via CMOS camera. The effect of the co-flow temperatures(1 473, 1 673 and 1 873 K), oxygen concentrations(5%, 10% and 20%) were considered. Results show that the ignition delay distance of torrefacted lignite particles is slightly larger than that of raw lignite particles under the same co-flow temperature and oxygen concentration. Under the oxygen concentration of 5%, the ignition delay distance of the torrefacted lignite at 200 ℃ are increased by 0.24, 0.28 and 0.13 cm when comparing with that of the raw lignite particles, respectively. Additionally, the increase of torrefaction temperature significantly decreases the ignition delay distance of lignite particles. Under case of 1 673 K and 5% O_2, the ignition delay distance of torrefacted lignite at 200, 250 and 300 ℃ are increased by 0.28, 0.16 and 0.11 cm when comparing with that of raw lignite, respectively.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 13566K]

  • Effect of load change on fly ash properties in a 1000MW coal-fired unit

    ZHENG Guibo;WU Jianqun;WU Hao;XUE Ningtao;LIU Fangqi;XU Guorong;YU Dunxi;Guangdong Yuedian Jinghai Power Generation Co.,Ltd.;State Key Laboratory of Coal Combustion,Huazhong University of Science & Technology;

    The peak load regulation operation of coal-fired units is an important measure to improve the consumption capacity of renewable energy, but it will have an evident impact on fuel combustion process and system. Fly ash properties are closely related to ash slagging behavior, dust removal equipment performance and particulate matter emission. However, little research has been done in the past. The influence of load change of coal-fired boiler on fly ash characteristics was studied to guide the prevention and control of ash related problems such as furnace fouling and slagging and particulate matter emission. In this work, fly ashes were sampled before ESP in a 1 000 MW coal-fired boiler under 60% and 90% operating load. Chemical composition, mineral species, particle size distributions and shape characteristics of fly ash were analyzed by advanced computer automatically controlled scanning electron microscope(CCSEM). The fly ash fusibility was analyzed by a digital imaging coal ash fusibility system. The effects of boiler operating load changing on ash properties and ash melting behaviors were investigated. The results show that changing of operation load has insignificant effect on fly ash chemical composition. Degree of mineral interaction is the key factor affecting the particle size distribution of fly ash. Low operation load of boiler suppresses the migration of Ca and Fe bearing minerals in coal to aluminosilicates, which results in finer fly ash particle size distribution. The D_(50) of fly ash decreases from about 40 μm to 30 μm. Compared withfly ash in low load operation condition, the melting of fly ash in the furnace under the low load operation condition is restrained. The proportion of molten fly ash from low load operation condition is about 10% lower than that from the high load operation condition, which is mainly attributed to the lower combustion temperature under low load operation condition.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 11899K]

  • Experiment of co-disposal of domestic waste and dioxins emission in coal-fired power plants

    WANG Xuebin;ZHOU Ao;MA Jiangdong;WANG Jing;WANG Fengqin;WANG Jianjun;ZHANG Lan;DAI Gaofeng;School of Energy and Power Engineering,Xi′an Jiaotong University;The Boiler & Pressure Vessel Safety Inspection Institute of Henan Province;Shaanxi Electric Power Design Institute Co.,Ltd.,China Energy Construction Group;Zhaoyuan Huichao New Energy Technology Co.,Ltd.;

    With the development of the economy and society in China, the production of municipal domestic waste is rapidly increasing, and the harmless treatment of domestic waste, especially the reduction of dioxins, has been a major research challenge. A new technical proposal of flexible coupled disposal of domestic waste by anaerobic pyrolysis was proposed for a 2×55 MW coal-fired unit for the first time. The industrial experiment of coupled co-disposal of wasteanaerobic pyrolysis products was carried out, and the dioxins generation and emission characteristics of this coal-fired unit were mainly tested. It's proved that the process proposal cannot only realize the co-disposal of domestic waste, but also ensure the normal operation of the system self-balancing when the coal-fired unit is shut down for maintenance.The results show that the dioxins content generated by waste treatment using this process route is much lower than that generated by direct waste incineration.When pulverized coal is burned, the mass concentration of dioxins in flue gas is 6.05×10~(-3) ng/m~3(calculated by TEQ, the same below). When the garbage coupling ratio is 4%, the mass concentration of dioxins in the flue gas is 5.34×10~(-3)ng/m~3. The mass concentration of dioxins in the final flue gas is 1.145×10~(-2) ng/m~3 and 1.074×10~(-2) ng/m~3 respectively after the maximum conversion of dioxins mass concentration emitted by waste pyrolysis oil and gas combustion.There is little difference in dioxins content in flue gas between waste mixed combustion and pure coal combustion, and they both meet the requirements of dioxins emission limit of 0.02 ng/m~3 in the Emission Standard of Air Pollutants from Coal-fired Coupled Sludge Power Plants in Shanghai.The study show that when the anaerobic pyrolysis coupled disposal process is adopted, the proportion of waste coupling is controlled to be less than 4%, and the dioxins emission in the flue gas of coal-fired coupled waste will not increase significantly.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 16962K]

  • Slagging characteristics of waste incinerator throat wall

    XU Yanwei;WANG Junjie;YUAN Ye;TAN Jiaxin;ZHU Yanqun;HE Yong;WANG Zhihua;Everbright Environment Technology (China) Ltd.;State Key Laboratory of Clean Energy Utilization,Zhejiang University;

    In order to study the slagging characteristics of waste incinerator walls, three pieces of slag were collected on site from the front arch wall, rear arch wall and side wall in the throat area. The ash fusion point tester, scanning electron microscopy(SEM)/energy dispersive X-ray(EDX), and X-ray diffractometer(XRD) analytical methods were used to determine the melting characteristics, microscopic morphology, element distribution, and phase composition and other physical and chemical properties of slag samples of slag. For the layered slag samples, elemental analysis and phase analysis were carried out along the growth direction of the slag. The results show that the difference in the characteristic temperatures of the three slag samples is small, and the softening temperature is less than 1 260 ℃, all of which are easy to slagging. The micromorphology of the three slag samples are similar through scanning electron microscope, mainly rock particles, indicating that the ash particles directly adhere to the furnace throat wall or slag surface without melting and spheroidization. The distribution of K, Na, and Al in the slag sample is similar, and the three elements gradually decrease along the slag growth direction.The K、Na and Al form three feldspar substances, such as KAlSi_3O_8 with a melting point of 1 130 ℃, KAlSi_2O_6 with a melting point of 1 100 ℃, and NaAlSi_3O_8 with a melting point of 1 100 ℃. The three low-melting feldspars are viscous after melting and are easy to deposit on the wall or slag surface. Along the growth direction of the slag sample, the content of the Ca gradually increases, and the Si/Ca is 0.8-1.1. Through the XRD, it is found that Si and Ca form the Ca_2MgSi_2O_7, which is the most important substance in the slag sample with a melting point of 1 450 ℃. The high melting point of Ca_2MgSi_2O_7 determines that only when the slag grows to a certain thickness, the outer surface of the slag begins to melt, which can prevent the slag from continuing to grow.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 24137K]

  • Emission characteristics of VOCs under the condition of biomass blending combustion

    YAN Zhonghao;GAO Yu;ZHANG Yong;JI Lijuan;LIU Xinyu;PU Linmao;CHEN Shixin;School of Environmental and Chemical Enginering,Shenyang University of Technology;Shenyang Ecological Environment Monitoring Center of Liaoning Province;

    In order to understand the emission characteristics of volatile organic compounds(VOCs) in the flue gas under biomass co-combustion, the research on the emission characteristics of volatile organic compounds in the flue gas was carried out on a 58 MW circulating fluidized bed(CFB) unit. The results show that the emissions of VOCs and NO_x and SO_2 can be significantly reduced due to the co-firing of biomass. The change of the combustion characteristics of the mixed fuel leads to the emission reduction of VOCs. The emission reduction of VOCs is most obvious when the biomass mixing ratio increases from 20% to 30%. The reason for the reduction of NO_x and SO_2 emissions is that biomass contains less S and N elements. The emission of pollutants such as VOCs is the lowest when the biomass blending ratio is 40%. Based on the actual operation of the power plant, the optimal mixing ratio is 30%.The analysis show that the amount of VOCs components has a strong positive correlation with the proportion of biomass in the fuel. The emission of VOCs under the condition of biomass blending has different characteristics from coal-fired boilers and biomass boilers.Under the two different mixing ratios, the largest proportion of VOCs emissions is benzene series, reaching 44.38%(20%) and 33.75%(40%), respectively. At 20% blending ratio, it is followed by alkanes(33.62%), esters(9.96%) and so on. At 40% blending ratio, esters(22.75%), alkanes(16.16%) and so on are followed. The emission of benzene series is dominated by benzene and toluene, the emission of alkanes is dominated by n-hexane, and the emission of esters is dominated by ethyl acetate. The ozone formation potential(OFP) was analyzed by the maximum incremental reactivity method. The contribution of ozone generation potential at 20% and 40% mixing ratios was mainly from benzene series, which contributed 69.88% and 70.24%, respectively, and The contribution of alkanes could also account for 25.76% and 17.75%.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 10688K]

  • Simulation study on the effect of deflector angle on atomization and evaporation performance of desulfurization wastewater

    JIA Shaodan;MA Lun;CHEN Xinke;FANG Qingyan;LI Debo;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;Electric Power Research Institute of Guangdong Power Grid Co.,Ltd.;

    Rotary spray drying technology, as a zero-discharge treatment technology for desulfurization wastewater, has the advantages of good adaptability to wastewater, low energy consumption, low investment, and broad application prospects. A 600 MW thermal power plant unit desulfurization wastewater spray drying tower was used as the research object, an atomization evaporation model was established, and the numerical simulation study on the influence of the deflector angle in the spray drying tower on the atomization and evaporation performance of desulfurization wastewater was carried out. The results show that the gas distributor in the drying tower divides the flue gas into two flue gas flows through the inner and outer channels. The flue gas in the inner channel first contacts with the droplets after atomization of the evaporative desulfurization wastewater, which directly affects the evaporation of the desulfurization wastewater. The flue gas in the outer flow channel can inhibit the vortex effect generated by the flue gas in the inner flow channel, and prevent the spray of atomized droplets on the wall surface of the drying tower from causing corrosion. A low temperature area is formed below the atomizer, where the relative velocity and temperature difference between the flue gas and the droplets are relatively large, which is the main area for atomization droplet evaporation. The influence of the deflection angle of the inner deflector in the inner flow channel on the atomization and evaporation performance of waste water is more obvious than that of the outer deflector. The smaller the angle of the inner guide plate in the inner flow channel is, the larger the angle of the inner guide plate in the outer flow channel is, the more flue gas that enters the inner flow channel is, the shorter the evaporation time and evaporation distance of desulfurization wastewater is, and the more significant the improvement of its evaporation performance is. Comprehensive consideration, in actual operation, it is recommended to set the angle of the deflectors of the inner flow channel to 0°, and the angle of the deflectors of the outer flow channel to be set to 45°.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 28844K]

  • Analysis and suggestion on carbon accounting of thermal power enterprises under the background of carbon peak and carbon neutrality

    LU Weiye;CHEN Xiaoxuan;LU Jidong;LI Yuesheng;YAO Shunchun;School of Electric Power,South China University of Technology;Shunde Branch,Guangdong Institute of Special Equipment Inspection and Research;Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization;

    With the the proposal of national goal of "carbon peaking and carbon neutrality", thermal power enterprises have become the forerunners and main force of the goal, and have taken the lead in entering the national carbon trading market. The carbon emission report of emission control enterprise is formed by the historical annual data collected by enterprises according to the quality control plan, which is verified by the third party verification agency and forms the final result. The quality of carbon emission data is the focus, which directly determines the fairness of carbon trading. With the rapid increase in the number of companies included in emission control and the in-depth development of carbon verification work, carbon emission verification has reflected some problems on the government side, verification agency side and enterprise side that are urgent to develop carbon measurement technology to solve. The experience of greenhouse gas verification and continuous monitoring at home and abroad was summarized and analyzed, developed countries such as Europe and the United States developed earlier and initially formed their own carbon measurement systems. However, the continuous monitoring technology for greenhouse gas emissions in China was still in the pilot exploration stage, lacking a complete carbon measurement system, standards and policies. To ensure the quality of carbon emission data, specific methods based on verification and supplemented by continuous monitoring were proposed. It is suggested to introduce the rapid analysis and measurement technology of coal quality and establish the coal quality database system. The research on laws, regulations, policies and system construction of carbon emission monitoring is carried out, the corresponding technical standards and quality assurance system are established, the tackling technical difficulties of continuous monitoring of greenhouse gases are focused on, a greenhouse gas emission data information management platform is built, and the continuous monitoring pilot of carbon emissions in the thermal power industry is firstly carried out, so as to promote the construction of carbon measurement system in China's thermal power enterprises, provide support for the comprehensive implementation of continuous monitoring of carbon emissions in all industries across the country, and provide a strong guarantee for the overall and orderly implementation of carbon peak and carbon neutralization work and the promotion of high-quality economic and social development.

    2023 01 v.29;No.149 [Abstract][OnlineView][HTML全文][Download 14556K]
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