2024年S2期目次

  • Dynamic simulation analysis and optimization of vibrating screen for coal preparation

    CHEN Fan;WANG Bin;CHN Energy Shendong Coal Group Co.,Ltd.;

    ZK1548 vibrating screen was taken as the research object and the mechanical analysis was carried on. By using ANSYS Workbench to conduct static and dynamic research on the vibrating screen, it was found that the sieve structure strength was not up to standard. Then, the response surface design and the multi-objective genetic algorithm were used to optimally analyze the structure. Finally, the results show that the deformation and stress distribution of the vibrating screen are obviously improved after optimization.

    2024 S2 v.30 [Abstract][OnlineView][Download 1273K]

  • Design and analysis of magnetorheological damper for mining vibrating screen

    SONG Wenge;CHN Energy Shendong Coal Group Co.,Ltd.;

    Aiming at the problem of irregular and harmful vibration when the vibrating screen starts and stops, a novel type of intelligent magnetorheological damper that can be installed in the base of the vibrating screen was designed to improve the working effect of the vibrating screen and suppress the harmful vibration by intelligently controlling the damping force of the magnetorheological damper. The structure of the traditional magnetorheological damper was improved, and a magnetorheological damper with large damping force for vibrating screen was designed and used to analyze the effects of the height of the working gap of magnetorheological fluid, the magnetically conductive material and the coil current on the distribution of the magnetic field and the magnetic induction strength of the new intelligent magnetorheological fluid damper by using Maxwell, an electromagnetism simulation software. The results show that the magnetic induction strength at the working gap decreases with the increase of the height of the working gap of the magnetorheological fluid, and the higher the material of magnetic permeability is used, the higher the magnetic induction strength at the working gap is.

    2024 S2 v.30 [Abstract][OnlineView][Download 2353K]

  • Detection of foreign objects in coal piles of belt conveyors based on YOLOv5

    CHEN Shitao;ZHANG Min;LI Chao;CHN Energy Shendong Coal Group Co.,Ltd.;

    There are impurities in the coal flow transported by the belt conveyor, which can lead to tearing of the conveyor belt. A foreign object recognition method for belt conveyors based on YOLOv5 and machine vision processing was proposed to address the vulnerability of underground coal mine image acquisition to environmental impacts such as lighting and noise, as well as the significant electrical noise generated by photoelectric detection equipment that affects imaging quality. The method first uses Gaussian filter to eliminate salt-and-pepper noise and enhance the image contrast. Finally, the image was divided into conveyor belts and two other regions for feature extraction. The experiment shows that this method improves the quality of the extracted image while solving the problem of unstable recognition of small targets by the YOLOv5 model.

    2024 S2 v.30 [Abstract][OnlineView][Download 3154K]

  • Wear law of slurry pump under coarse particle working condition

    GUO Jianjun;CHN Energy Shendong Coal Group Co.,Ltd.;

    When conveying solid-liquid two-phase slurry, the overflow components of the slurry pump will wear due to the impact of solid particles, and the mass concentration and particle size of the particles will have a significant impact on the degree of wear. Coarse particle working conditions often lead to significant wear on the flow components of the slurry pump, so it is important to explore the wear patterns of the slurry pump under coarse particle working conditions. This article establishes a simulation model for solid-liquid two-phase flow in a slurry pump, and analyzes the changes in the internal flow field and particle motion of the slurry pump under coarse particle conditions(three particle diameters). Based on the wear model, the wear patterns of different flow passage components of the slurry pump were analyzed. The results indicate that under coarse particle conditions, particles are mainly distributed in the volute flow channel and blade pressure surface. When the particle diameter is 1 mm, the particle distribution is more dispersed and more susceptible to the influence of the flow field. The maximum wear of the volute is negatively correlated with the particle diameter. When the particle diameter is small, the wear area shows a patchy distribution. As the particle diameter increases, particle wear is mainly distributed in the volute flow channel and the inlet side of the tongue. The particle diameter has little effect on the maximum wear of the blade, and particle wear is mainly distributed on the pressure surface of the blade.

    2024 S2 v.30 [Abstract][OnlineView][Download 856K]

  • Media migration process in power coal preparation plant

    CHEN Fan;CHN Energy Shendong Coal Group Co.,Ltd.;

    The media migration process serves as the core link in the coal beneficiation process. In the traditional media migration process, the synergistic effect of the heavy media sorting link has some limitations, which leads to product quality and production efficiency difficult to meet today's high standard of energy demand. In order to explore the technical key points in the media migration process, to find and solve the existing problems in the current process, and to improve the efficiency of the process and product quality, a media migration process study was carried out in a coal preparation plant in the west, and the results show that: there are two main media loss paths in the lump coal system of the plant, and the media loss caused by product carry away occupies 63.53% of the total media loss; The media loss caused by magnetic separation tailings and centrifugal liquid carrying away occupies 36.47% of the total media loss. The grading screen and demeshing screen of the lump coal system work normally, and the media carried on the screen of the demeshing screen of the fine coal after sorting is more than 0.10 kg/t, but the content of magnetic material after the fine coal centrifuge reaches 0.72 kg/t, and the amount of media carried away by the fine coal product is very high.

    2024 S2 v.30 [Abstract][OnlineView][Download 109K]

  • Intelligent fault diagnosis method of slurry pump bearing based on VMD-MSE

    LI Jiangtao;CHN Energy Shendong Coal Group Co.,Ltd.;

    Aiming at the noise problem in bearing vibration signals, a hybrid algorithm based on VMD and MSE was proposed for bearing fault diagnosis. The original signal is decomposed using the variational modal decomposition(VMD) algorithm, and the effective components are screened by the correlation coefficient method, after which the signal is reconstructed. Then, the multi-scale entropy(MSE) algorithm is applied to extract the feature vectors and combined with support vector machine(SVM) for fault diagnosis. The results of the study show that the recognition accuracy of this method in bearing fault diagnosis reaches 98.33%.

    2024 S2 v.30 [Abstract][OnlineView][Download 2264K]

  • Control strategy of belt conveyor braking system based on genetic algorithm

    XUE Hongwei;ZHAO Hui;Shangwan Coal Preparation Plant,CHN Energy Shengdong Coal Preparation Center;

    Belt conveyor is an indispensable transportation equipment in coal mine production, and the reliability of its braking system is directly related to the safe operation of the conveyor. Disc brake system has been widely used due to its advantages of simple structure, mature technology, convenient operation and low cost. In view of the actual working condition of the disc brake device of belt conveyor, a new type of electro-hydraulic proportional hydraulic brake system with the function of pressure preservation was designed and analyzed in depth. Firstly, the operation principle of the system under different working conditions was introduced, and the relevant mathematical model was established. Then, the electro-hydraulic proportional hydraulic braking system was simulated and analyzed using the AMESim platform to verify the reasonableness of the design. Meanwhile, a PID closed-loop control strategy based on genetic algorithm was designed to meet the specific control requirements of the disk brake system. The results show that the optimized PID closed-loop control strategy using genetic algorithm significantly improves the overall performance of the braking system with good adaptability and effectiveness.

    2024 S2 v.30 [Abstract][OnlineView][Download 2088K]

  • TiCN reinforced Ni-based composite coating on the surface of slurry pump flow components

    SU Cuihua;WANG Zhenlong;Shangwan Coal Preparation Plant,CHN Energy Shengdong Coal Preparation Center;

    Aiming at the current research and application status of slurry pump overflow component materials, this paper carries out laser fusion cladding on the surface of high-chromium cast iron KmTBCr_(26)Mo, and selects TiCN ceramic particles powder and Ni_(60) self-soluble metal powder to prepare TiCN-enhanced nickel-based fusion cladding layer. The effects of TiCN content on the phase composition, microstructure, microhardness and friction and wear properties of the fused cladding layers were investigated. The results show that the TiCN-enhanced nickel-based fused cladding layer mainly contains the phases of γ-Ni, [Ni, Fe] solid solution, Cr_(23)C_6, Cr_3C_2 and TiCN, etc. The incorporation of TiCN ceramic particles effectively inhibits the growth of γ-Ni grains, refines the organization of the fused cladding layer, and results in a more homogeneous distribution of the grains. However, too much TiCN can lead to cracks and a large number of pores in the cladding layer. The hardness of the Ni-based fused cladding layer without TiCN was small, and the hardness of the fused cladding layer showed a tendency of increasing and then decreasing with the increase of TiCN content. The results of friction wear tests show that the addition of TiCN significantly improves the wear resistance of Ni-based composite fused cladding layers.

    2024 S2 v.30 [Abstract][OnlineView][Download 953K]

  • Condition monitoring method of coal harvester based on wavelet packet energy spectrum correlation coefficient

    TIAN Yanfeng;WANG Anjia;Shangwan Coal Preparation Plant,CHN Energy Shengdong Coal Preparation Center;

    This paper takes the coal separator as the research object, analyzes and monitors its vibration characteristics under the working state, extracts the operating state characteristics from the acceleration vibration signal, and proposes a new method for monitoring the working state of the coal separator according to the Wavelet packet decomposition theory. Combined with the energy theory, the Wavelet packet decomposition reconstruction signal is divided into frequency bands to obtain the energy value, and the obtained energy value is written in vector form. According to the concept of correlation coefficient, the correlation coefficient of each wavelet packet energy vector is calculated to judge the operating state of the coal separator. The results indicate that this method can effectively alert the status of the coal preparation machine and ensure the safe operation of the coal preparation equipment.

    2024 S2 v.30 [Abstract][OnlineView][Download 279K]

  • Key technologies and methods for product family modular design of pendulum jaw crusher

    GAO Pan;WANG Zhen;Shangwan Coal Preparation Plant,CHN Energy Shengdong Coal Preparation Center;

    Pendulum jaw crusher has the advantages of simple structure and reliable operation, and is one of the main models of jaw crushing equipment used for coarse ore crushing. In this paper, the key technology and method of modular design for jaw crusher family are proposed to meet the diversified customer demand and mass customization design goal. Firstly, the qualitative design requirements and quantitative design parameters of product family are extracted. Secondly, the function-structure modules of product family are obtained by using function-structure mapping and variant index based analysis, and the module types are classified. Then, an object-oriented generic BOM product family model is proposed. It not only expresses the instantiation and parametric adjustment data structure of the module, but also supports the configuration design of the product facing customer requirements. Finally, a custom design case of pendulum jaw crusher family in coal preparation plant is used to demonstrate the effectiveness of the proposed modular design technical system.

    2024 S2 v.30 [Abstract][OnlineView][Download 586K]

  • Condition monitoring method of coal harvester based on wavelet packet energy spectrum correlation coefficient

    ZHANG Xinyuan;LI Fuping;NAN Chaoyun;Shangwan Coal Preparation Plant,CHN Energy Shengdong Coal Preparation Center;

    Based on the EDEM-FLUENT coupling method, the motion trajectory of coal particles and coal gangue particles in the spiral concentrator was studied, and the separation effect of mixed particles in the spiral concentrator was further explored. Use Solidworks to model the fluid domain of the spiral concentrator chute. The EDEM-FLUENT coupling method is used to achieve the coupling simulation of particles and water flow, which truly reflects the sorting results of large particle coal and coal gangue sorted by the spiral separator. The results show that coal and gangue with spherical particles are beneficial for improving the separation effect, and the closer the feed particles are to the spherical particles, the better. For this type of spiral concentrator, when sorting ball shaped coal and coal gangue particles, the scraper of the interceptor should be adjusted to a distance of 98-100 mm from the inner groove for the best sorting effect. This simulation analysis method provides guidance for improving the spiral beneficiation process and designing and manufacturing spiral beneficiation machines.

    2024 S2 v.30 [Abstract][OnlineView][Download 339K]

  • Dynamic reliability analysis of the double-toothed roll crusher

    ZHAO Xinglei;YAN Jianhua;LIN Jun;Shangwan Coal Preparation Plant,CHN Energy Shengdong Coal Preparation Center;

    The tooth is a primary functional component within the toothed roll crusher. During the operational process of the crusher, the crushing teeth are susceptible to fractures due to the dynamic loads exerted by the material. To further enhance the stability and reliability of the toothed roll crusher, with a focus on the double-toothed crusher, the influence of random factors on the geometric parameters of the tooth tip is taken into consideration. The study aims to investigate the dynamic reliability of the crushing teeth under the influence of forced vibrations. By considering the force characteristics that the crushing teeth experience throughout the material crushing process, the complex modal superposition method is enlisted to calculate the vibration response of the crushing teeth. The stress attributes of the crushing teeth are ascertained via the shape function method, which effectively harnesses the vibration responses originating from different nodes. Drawing upon the tenets of reliability theory, the ramifications of random parameter effects on the dynamic stress affecting critical sections of the crushing teeth are meticulously analyzed using the random perturbation method. Implementing the fourth-order moment method, a dynamic reliability analysis of the gyratory crusher tooth is performed, subsequently validated through the utilization of the Monte Carlo method to verify the dynamic reliability of the crushing teeth.

    2024 S2 v.30 [Abstract][OnlineView][Download 321K]

  • Hydraulic synchronous automatic tensioning device of scraper conveyor

    ZENG Hongjiu;ZHAO Huanyu;CHN Energy Shendong Coal Group Co.,Ltd.;

    Due to the complex underground environment of coal mines, bad working conditions such as coal wall gang and scraper chain jamming often occur, which have a huge impact on the scraper conveyor, so it is necessary to control the chain tension accordingly to reduce tension fluctuations and reduce accident rates. By measuring the overhang of the minimum tension point of the chain, and comparing it with the set chain overhang, the state of the scraper conveyor is judged, and the corresponding command is issued to the solenoid valve of the hydraulic servo system in time to control the pressure of the hydraulic tensioning system, so as to adjust the chain tension of the scraper conveyor in time to realize the automatic tension of the chain. The dynamic equation of the scraper conveyor is derived, and the finite element model parameters, running resistance and tension force of the scraper conveyor are analyzed. Based on the above analysis parameters, the simulation model of AMESim and transfer function of hydraulic servo tensioning system is established, and the following characteristics of the displacement signal of the hydraulic cylinder of the hydraulic tensioning system and the Bird diagram of the two models are analyzed through simulation, and the analysis results show that the hydraulic synchronous automatic tensioning system has certain feasibility.

    2024 S2 v.30 [Abstract][OnlineView][Download 276K]

  • Effect of different nozzle types on the removal of media in demineralization sieves

    LIU Qinju;WANG Bin;CHN Energy Shendong Coal Group Co.,Ltd.;

    In order to explore the effect of different types of nozzles on de-bonding under different operating conditions, the experimental study was carried out. The results show that: compared with wide-angle fan nozzles, fan-shaped double-hole nozzles can reduce the magnetic content on the screen by at least 8.7% or more. Compared with the fan-shaped single-hole nozzles, stabilizing the media consumption at the same time, to a certain extent, the water consumption of about 17.7% can be saved, and the spray angle are larger than the fan-shaped single-hole nozzles, which can reduce the number of nozzles used in practical applications. The experimental results prove that the fan-shaped double-orifice nozzle has a good effect of de-medialization.

    2024 S2 v.30 [Abstract][OnlineView][Download 579K]

  • Dry mist dust suppression technology in coal processing plant belt machine application status and development

    ZHANG Ning;LIU Gang;LI Jiaoguo;Baode Coal Mine of CHN Energy Shendong Coal Group Co.,Ltd.;

    Belt conveyor is a common material transportation equipment. The dust generated during its operation is particularly prominent. Although the traditional wet dust suppression can slow down the spread of dust to a certain extent, there are problems such as water consumption and unfavorable equipment maintenance. The wet dust removal technology for dust less than 10 μm processing effect is also poor. This paper selects a coal preparation plant inspection belt machine as the object and briefly introduces the causes of dust and dust hazards, completely and systematically introduces the existing dry mist dust suppression technology principle and equipment, and finally further evaluates the dust removal effect of the dry mist dust suppression technology through the monitoring equipment in the field of the actual application and put forward proposals for the future development of the technology.

    2024 S2 v.30 [Abstract][OnlineView][Download 174K]

  • Fault monitoring method for mining demineralization screens based on imbalanced data

    YANG Jun;LI Xuanhua;ZHANG Leiyun;Baode Coal Mine of CHN Energy Shendong Coal Group Co.,Ltd.;

    Fault monitoring of mining equipment is crucial for enhancing the continuity and safety of coal mining operations. However, the scarcity and difficulty in collecting fault data in actual industrial processes create imbalance issues, which hinder the practical application of data-driven fault monitoring algorithms. This paper addresses the intra-class imbalance problem in real equipment fault monitoring by proposing an enhanced weighted oversampling algorithm. The algorithm is based on Borderline-SMOTE, which uses the distribution of K-nearest neighbor samples to perform weighted oversampling with borderline samples as the root samples. It utilizes LOF for the identification of new outlier samples, thereby improving the accuracy of the generated samples. Experimental fault monitoring on an actual mining demineralization screen demonstrates that the proposed method outperforms traditional oversampling approaches in terms of accuracy and classification effectiveness.

    2024 S2 v.30 [Abstract][OnlineView][Download 233K]

  • Application of an enhanced synthetic oversampling algorithm based ontomek in fault monitoring of mining machinery

    LI Xing;SONG Yanbin;LI Zhaohui;Baode Coal Mine of CHN Energy Shendong Coal Group Co.,Ltd.;

    Fault monitoring of mining machinery and equipment can ensure the smooth running of coal mine production. Data-based fault monitoring algorithms require a large amount of fault data, which is difficult to obtain in actual coal mine production. In this paper, for the data imbalance problem in equipment fault monitoring, the data screening function of TOMEKLINKS was utilized to improve the stochastic oversampling algorithm(SMOTE) to improve the accuracy of equipment fault monitoring. Using the TOMEKLINKS to identify the characteristics of boundary samples, combined with the Borderline-SMOTE algorithm, boundary samples are determined from the perspectives of k-nearest neighbors of the minority class and the nearest neighbors of the samples. Different sampling multiples are assigned to different samples, thereby enhancing the machine learning algorithm′s ability to recognize the classification boundaries of fault data. Experiments conducted on a mining dewatering screen have verified that the algorithm presented in this paper improves the fault monitoring accuracy compared to classical algorithms, proving to be an effective method for solving fault monitoring of mining equipment.

    2024 S2 v.30 [Abstract][OnlineView][Download 246K]

  • Selective ash content identification method based on Laplace distribution

    MA Zhijun;Yujialiang Coal Washing Plant,Shendong Coal Preparation Center;

    In this study, we address the challenge of distinguishing abnormal variations in ash content data that occur during the heavy medium coal preparation process. We present a concise overview of the heavy medium coal preparation process and propose a robust system identification algorithm by modeling system noise using the thick-tailed Laplace distribution. Subsequently, we construct a selective ash identification model based on the Laplace distribution. The algorithm adaptively adjusts the tail length during its derivation to effectively capture outliers that deviate significantly from the central tendency, thereby enhancing its robustness in resisting the influence of abnormal values. By formulating the problem within the framework of the expectation maximization algorithm, we derive the mathematical expression for estimating the parameters of interest. Lastly, we validate the effectiveness of our proposed algorithm through numerical simulation examples. The experimental results demonstrate that our model accurately identifies the ash content, thus serving as a valuable reference for ash identification in the heavy medium coal preparation process.

    2024 S2 v.30 [Abstract][OnlineView][Download 1197K]

  • Recent progress of synthesis and application of fly ash based tobermorite

    ZHOU Xiuyan;LI Xiaoding;LI Na;WANG Qingxu;WU Hao;TIAN Shulei;School of Resources and Materials,Northeastern University at Qinhuangdao;State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences;School of Resources and Civil Engineering,Northeastern University;

    Tobermorite is an important class of silicate minerals that is widely used for the removal of heavy metal ions from water because of its excellent ion exchange properties. However, natural tobermorite has low mineral content and low purity, so hydrothermal synthesis is often used. The fly ash produced every year contains a large amount of active glass phase and abundant Ca, Si and Al elements, which can be used as the main raw material for the synthesis of tobermorite. Therefore, the classification, physical and chemical properties of fly ash as well as the synthesis mechanism, influencing factors, synthesis process and environmental applications of tobermorite are summarized. Fly ash can be used as raw material to synthesize well-crystallized needle-like tobermorite, which has good adsorption performance and can be widely used to treat heavy metal ions in wastewater, and its adsorption effect is ideal and low cost, which can realize the treatment of waste with waste.

    2024 S2 v.30 [Abstract][OnlineView][Download 505K]

  • 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,ZhengzhouUniversity;

    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_3etc). 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 expand the application fields of carbon residue-based materials but also have long-term research and development and application prospects.

    2024 S2 v.30 [Abstract][OnlineView][Download 341K]

  • Recent advances in low temperature CO2 methanation on Ni-based catalysts

    TIAN Jumei;GAO Xinhua;LI Yachao;GUO Qingjie;LIANG Jie;DUAN bin;National Quality Supervision and Inspection Center for Coal and Coal Chemical Products (Ningxia),Ningxia Academy of Metrology &Quality Inspection;State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,School of Chemistry and Chemical Engineering,Ningxia University;

    Carbon dioxide(CO_2) methanation reaction is one of the most important ways to produce cleaner fuels and has increasingly attracted more attention due to its potential in fossil fuel dependency and the utilization of surplus renewable electricity. Since the CO_2 methanation reaction is high exothermic, the reaction process is thermodynamically favorable, but its kinetics are limited at low temperatures. Recently, Ni-based catalysts exhibit high activity and stability when used in CO_2 methanation at low temperature and have been widely studied from industrial and academic community. Herein, the mini-review introduced the research progress of mechanism and thermodynamics of CO_2 methanation reaction, the effects of the catalyst synthesis methods, promoter and support on the performances of CO_2 methanation catalysts. A more energy-saving new CO_2 methanation technology and the design of high performance catalyst for low-temperature CO_2 methanation in the future was discussed. The results show that the synthesis method affects the physicochemical properties of the catalyst, which in turn affects the CO_2 conversion and energy efficiency; the selection of promoters or supports can improve the dispersion and stability of Ni-based catalysts. Therefore, the design and preparation of highly active and stable Ni-based catalysts is the key to the efficient conversion of low temperature CO_2 methanation.

    2024 S2 v.30 [Abstract][OnlineView][Download 1547K]

  • Study on pore enlargement of coal tar hydrodemetallization catalyst support

    MA Bowen;Research Institute of Coal Chemistry,China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;

    Selection of pseudo-boehmite suitable for preparation of macroporous alumina support, and adding physical pore enlarging agent in the preparation of coal tar hydrodemetallization catalysts support, three peak alumina support with three pore distribution were prepared. Characterized by N_2 adsorption-desorption, mercury intrusion test, X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM),the formation and distribution of macropores in acid free molding support are mainly determined by the properties of pseudo-boehmite, the type and quantity of pore enlarging agent, and the pore enlarging agent has no effect on the crystalline phase of alumina. The surface active pore enlarging agent PEA-4 has a good pore enlarging performance of alumina support. When its addition amount reaches 2%,the diffusion pores>100 nm in the support reach 48.9%,the proportion of pores<9 nm decreases to less than 10%,and the pore volume reaches 0.77 mL/g.

    2024 S2 v.30 [Abstract][OnlineView][Download 485K]

  • A prediction model of fly ash softening temperature was established based on the evolution mechanism of inorganic minerals

    LI Zhenxing;PEI Jiang;LIU Baoman;WU Xingzhe;XIAO Haiping;Guoneng Hebei Dingzhou Power Generation Co.,Ltd.;School of Energy,Power and Mechanical Engineering,North China Electric Power University;

    The different ash composition of coal affects the evolution of inorganic minerals at high temperature, which leads to the change of ash melting point. The experiment of ash melting point was carried out, and X-ray diffraction was used to analyze inorganic minerals in ash samples, combined with thermodynamic equilibrium calculation. The influence of the evolution of high temperature inorganic minerals on ash melting point of typical coal was compared and the softening temperature prediction model was established by the least square support vector machine(LSSVM) algorithm. The results showed that the ash melting point of B coal was 200 ℃ higher than that of A coal. Al_2O_3 and SiO_2 in fly ash were easy to form high melting point minerals such as mullite and quartz at high temperature, resulting in high melting point of ash. When the alkalic acid ratio of fly ash was relatively high, the fly ash was prone to aluminosilicification to produce a large number of low melting point minerals, such as alkali metal feldspar, pyroxene, etc., whose eutectic effect led to the decrease of the melting point of fly ash. The softening temperature prediction model was established based on LSSVM algorithm, taking the mass fraction of different ash components and the comprehensive evaluation index(Si-Al ratio, alkali-acid ratio) as input. The mean relative error of prediction was only 1.51%. Therefore, the model can accurately predict the melting characteristics of fly ash at high temperature.

    2024 S2 v.30 [Abstract][OnlineView][Download 1332K]

  • Study on modification mechanism of coal-based hard modified asphalt

    YANG Yaohui;SHEN Quanjun;CONG Bori;SHANG Hongfa;WEI Hui;Innovation Research Institute of Shandong Hi-Speed Group;Shandong key Laboratory of Road structure and Materials;Shandong Transportation Institute;

    Coal-based hard asphalt is a solid waste residue produced by direct liquefaction of coal hydrogenation to oil. Unlike the traditional coal tar asphalt containing toxic substances, the volatile substance of coal-based hard asphalt is non-toxic semi-saturated and hydrocarbon substances, which has the characteristics of high softening point, low penetration degree and low extensibility. It is a kind of asphalt modifier for environmental protection, and excellent performance. Its composition is similar to that of natural bitumen, showing low content of saturated content and aromatic content, and high content of gum and asphaltene. In order to investigate the modification mechanism of coal-based hard asphalt and composite modified asphalt, the dispersion development process, chemical functional group change and microphysical structure of coal-based hard bitumen and its modified bitumen were studied by fluorescence microscopy, Fourier infrared spectroscopy(FTIR), scanning electron microscopy(SEM) and other microscopic techniques. The results of fluorescence microscopy revealed the whole process change law of the modified asphalt fusion development, the modified asphalt from the initial uniformly dispersed phase to uniform continuous phase, at the same time, the test results also showed that the modified asphalt production and preparation technology determined in the study process is reasonable. The results of infrared spectrum curve show that the position of characteristic absorption peaks of matrix asphalt, coal-based hard asphalt, coal-based hard modified asphalt and composite modified asphalt is basically the same, but the strength of characteristic absorption peaks is different, indicating that the modification of matrix asphalt by coal-based hard asphalt and SBS modifier is mainly physical modification. The microstructure of the two modified bitumen is denser than that of the matrix asphalt and the coal-based hard bitumen. The honeycomb structure of the coal-based hard asphalt and the coal-based hard asphalt are transformed into the modified sawtooth structure, resulting in the formation of structural asphalt. The structural bitumen contributes to the improvement of the adhesion and high temperature stability of the modified bitumen. The surface of coal-based hard asphalt and SBS composite modified asphalt is dry and dull, and traces of swelling and development of SBS modifier can be clearly seen. In the development process of SBS modifier, light components in the matrix asphalt are consumed, which also contributes to the improvement of high temperature performance of modified asphalt.

    2024 S2 v.30 [Abstract][OnlineView][Download 1921K]

  • Study on pyrolysis and oxygen migration behavior of lignite under pressurized conditions

    Zhang Peiyun;Yan Haibo;Wang Jie;School of Resources and Environmental Engineering,East China University of Science and Technology;

    The slow pyrolysis was carried out by using a pressurized fixed-bed reactor for Yuxi lignite and Hami lignite to investigate the influence of pressure on the release rate of main gases, the distribution of main products, the composition of tar, and the transformation of oxygen element to the main products. Result showed that in the range pressure range of 0.1-1 MPa, elevating pressure promoted the yields of CO_2 and gaseous hydrocarbons, and this result was more noticeable for Yuxi lignite. The reason for this result was the intensified secondary cracking reactions. But the yields of H_(2 )and CO decreased with the elevation of pressure, and this was probably due to the volume-shrinking hydrogenation reaction and carbon deposition reaction of CO favored under elevated pressure. While elevating pressure led to the reduction of tar due to the intensified secondary cracking reactions, the number and proportion of lignite hydrocarbon compounds in the tar increased. Moreover, elevating pressure was beneficial to the deoxygenation of both char and tar, and more oxygen element was liberated in the form of CO_2 and H_2O.

    2024 S2 v.30 [Abstract][OnlineView][Download 566K]

  • Catalytic pyrolysis characteristics and kinetics of low-rank coal

    MA Xu;LIU Ping;LI Wenjun;ZHANG Haiyong;SU Qianqian;China Chemical Safety Association;College of Environmental Engineering,North China University of Science and Technology;China University of Mining and Technology-Beijing;

    Low rank coal is abundant, has low degree of coalification, high reactivity,,low utilization rate of direct combustion and high pollution, so it is hard to be made use fully. much research has been done on catalysts for coal pyrolysis, but it is rare to use nickel-loaded dolomite as catalysts for the catalytic pyrolysis of low-rank coal. In order to achieve the high-quality utilization of low-rank coal, Inner Mongolia lignite was studied. A nickel-based catalyst(Ni-dolomite) loaded by dolomite was prepared by equal volume impregnation and copper was added as co-catalyst. The effects of different catalysts on the pyrolysis process of Inner Mongolia lignitecarriedout by thermogravimetric(TG),the catalyst of best activity was scanned by electron microscope, and kinetics of the active pyrolysis stage was studied. The paper shows that the pyrolysis conversion rate of raw coal is 14.67% without catalyst added. The pyrolysis conversion of coal with 10% dolomite is 21.84%,which is 6.17% higher than that of raw coal. The results indicate that catalysts play a role in promoting coal pyrolysis and reducing the activation energy of pyrolysis, but the catalytic effects of different catalysts are different. However, the dolomite catalyst supported with Ni-Cu ratio of 1∶0.2 has the best catalytic effect on the pyrolysis of Inner Mongolia lignite, and the excessive Cu~(2+) will reduce the catalytic effect. Ni~(2+) and Cu~(2+) were uniformly distributed over the surface of the dolomite, and the surface area and pore size of the catalyst decreased after the dolomite was loaded with Ni~(2+) and Cu~(2+) by electron microscope scanning. The kinetic model of catalytic pyrolysis reaction was established and the kinetic parameters were calculated. When no catalyst was added, the activation energy of coal samples at 300-500 ℃ was 96.354 6 kJ/mol. With the addition of dolomite, the activation energy of coal samples decreases to 80.213 2 kJ/mol, indicating that dolomite has a certain catalytic effect on coal pyrolysis.The results of kinetic analysis are in good agreement with those of thermogravimetric analysis. 10%Ni/Cu(1∶0.2)-dolomite>10%Ni-dolomite>10%Ni/Cu(1∶0.5)-dolomite>dolomite in catalytic effect order.

    2024 S2 v.30 [Abstract][OnlineView][Download 215K]

  • The study on migration and release characteristics of chromium in pyrolysis of low rank coal

    ZHOU Lingmei;XIONG Kun;ZHENG Hao;ZHAO Yingjie;CHU Mo;CHU Li;QIN Qing;QU Beibei;School of Chemical&Environmental Engineering, China University Mining Technology-Beijing;

    Low rank coal reserves are abundant in China, and heavy metals will migrate to the pyrolysis products and environment during the pyrolysis process of low-rank coal, which not only affects the product quality but also pollends the environment. In order to study the migration characteristics of heavy metals during the pyrolysis of low-rank coal, this paper took Nuomaohu coal(NMH) of Xinjiang and high-sulfur coal of Inner Mongolia(GL) as experimental samples, and heavy metal chromium as the research object, studied the occurrence form of chromium by using step by step chemical extraction, and studied the effect of pyrolysis final temperature rise rate on the migration behavior of chromium(Cr) for raw coal pyrolysis. The single component was prepared by chemical extraction step by step, and the thermal stability of Cr was studied by pyrolysis. The results show that, the occurrence form of chromium(Cr) in NMH and GL were involving in the silico-aluminate binding state FC_2(34.8% and 26.4%),the organic bonded state FC_4(32.9% and 35.7%),the carbonate bound state FC_1(29.8% and 34.3%) and the disulfide binding state FC_3(2.5% and 3.6%). During pyrolysis, the release of chromium(Cr) from heating rate increases with the increase of heating rate.The release rate of Cr from NMH at 800 ℃ is 8.53%,which is much lower than that of GL 25.24%.

    2024 S2 v.30 [Abstract][OnlineView][Download 3470K]

  • Variation of fractal dimension and phase composition of coal gangue aggregate

    WANG Xunlong;XU Zesheng;JIAO Xiaomiao;WANG Xufan;TONG Jiangjin;WANG Shiqi;SHU Xinqian;LI Jun;School of Chemical and Environmental Engineering,China University of Mining & Technology-Beijing;Science and Technology Center,Coal Science Research Institute Co.,Ltd.;

    The shape characteristics of coal gangue aggregate is an important factor affecting its mechanical properties. Five particle sizes of coal gangue aggregate were selected. Based on image acquisition and processing technology, the fractal of projection area and projection perimeter was used to quantitatively analyze the shape of different particle sizes of coal gangue aggregate. At the same time, the fixed carbon content, high calorific value and XRD detection of different particle sizes were measured and the mineral composition was analyzed. Based on the correlation analysis method, the relationship between the shape fractal and the mineral composition of coal gangue aggregate was analyzed. The study found that the fractal dimension of 0.30-<0.60、0.60-<1.18、1.18-<2.36、2.36-<4.75、4.75-9.00 mm coal gangue aggregate are 1.085 4(R~2=0.985 9),1.080 4(R~2=0.962 7),1.065 4(R~2=0.967 3),1.023 4(R~2=0.979 5),0.973 8(R~2=0.942 6). The results of industrial analysis and XRD test show that with the increased of coal gangue aggregate particle size, the fractal dimension and high calorific value decrease, while the content of fixed carbon and kaolinite decrease gradually, but the content of quartz increase gradually. This phenomenon indicates that during the crushing process of coal gangue, quartz is enriched to coarse particles, and carbon and clay components are enriched to fine particles. The correlation analysis results show that the content of kaolinite(0.947) and fixed carbon(0.910) have a significant positive correlation with the fractal dimension of coal gangue aggregate. Based on the correlation coefficient method, the fractal dimension of coal gangue aggregate shape is related to the component content, which provides a new method for the joint analysis of coal gangue aggregate shape and component content to evaluate the quality of coal gangue aggregate, and provides a basis for the resource utilization of coal gangue.

    2024 S2 v.30 [Abstract][OnlineView][Download 381K]

  • Pyrolysis characteristics and kinetics of heavy components of different bituminous coals

    LIU Zhiming;CHEN Zijian;HAN Qian;YANG Xiaoqin;QIN Zhihong;School of Chemical Engineering and Technology,China University of Mining and Technology;

    By solvent extraction method, the heavy components(HC) of four types of bituminous coal were obtained, and the pyrolysis behavior of HC under different heating rates was investigated using a thermogravimetric analyzer. Based on the analysis of the thermogravimetric data of the HC,the pyrolysis characteristic parameters of the HC were determined, and the kinetics parameters of the HC were studied using the Doyle integral method. The results reveal that the pyrolysis initiation temperature(T_i),temperature of maximum mass loss rate(T_(max)),average mass loss rate(-(dw/dt)_(mean)),maximum mass loss rate(-(dw/dt)_(max)),and P all increase with the rising heating rate. However, the total pyrolysis mass loss rate(ΔW_(max)) of HC exhibits an overall decreasing trend with increasing heating rates. When the heating rate increases from 10 ℃/min to 40 ℃/min, the ΔW_(max) values of the four HC decrease by 1.26%,4.97%,5.03%,and 3.51%,respectively, as the dry ash-free carbon content(C_(daf)) increases. Simultaneously, the P values increase by 17,16,10,and 13 times, respectively. The dry ash-free volatile matter(V_(daf)) and hydrogen-to-carbon atomic ratio(H/C) of HC exhibit a strong positive correlation with P,with linear correlation coefficients(R~2) all exceeding 0.92. However, this correlation weakens with the increase in heating rate. Compared to V_(daf),H/C more effectively represents coal rank in characterizing the reactivity of HC during pyrolysis. The kinetic analysis reveals that the pyrolysis process of HC can be divided into three stages. The activation energy of the second pyrolysis stage is significantly higher than that of the first and third stages, ranging from 43 kJ/mol to 82 kJ/mol. The activation energy of each pyrolysis stage increases with the rising heating rate, and the reaction order was consistently 1. The R~2 values of the fitted lines all exceeds 0.99,indicating a significant kinetic compensation effect for HC.

    2024 S2 v.30 [Abstract][OnlineView][Download 332K]

  • Effect of crystallization time on the catalytic synthesis of anisole from phenol over MgAl hydrotalcite

    ZHANG Haiyong;LI Jie;MAI Lichan;GUO Jin;QI Tingting;ZHANG Shiji;WANG Yonggang;School of Chemical & Environmental Engineering,China University of Mining & Technology-Beijing;Institute of Chemistry,Chinese Academy of Sciences;

    The efficient selective conversion of phenol from coal tar to fine chemicals is important to the high-value utilization of coal. A series of MgAl hydrotalcite was prepared using co-precipitation method by changing crystallization time. MgAl hydrotalcite and its calcined products were characterized by XRD,ICP-OES,TG,SEM,CO_2-TPD and NH_3-TPD,and the catalytic performance of the calcined products for O-alkylation of phenol by dimethyl carbonate(DMC) to anisole were investigated. The results show that with the extension of crystallization time, the crystal size of hydrotalcite in both the a-axis and c-axis are increased, the particles are spherical clusters of plates and are increased with crystallization time, the pore volume and mean diameter are also increased. The weak bases, weak acids and strong acids are all increased while the strong bases are reduced. When phenol and DMC mixture(1∶3 mol ratio) was reacted on fixed bed reactor in gas phase at 325 ℃ and WHSV=2 h~(-1),the conversion of phenol is over 95 % over all catalyst, and the selectivity of anisole is increased with crystallization time. The conversion of phenol is 97.91%,and the selectivity of anisole is 91.33% over the catalyst prepared with 12 h crystallization time.

    2024 S2 v.30 [Abstract][OnlineView][Download 389K]

  • Physicochemical property analysis of coal-based nano carbon-hydrogen fuel with different particle sizes

    DU Shanzhou;WANG Liping;YUAN Duo;YANG Lei;YE Tao;Guoneng Zhunneng Group Co.,Ltd.;China Shenhua Halwusu Open-pit Coal Mine;Sanyi(Hainan)New Materials Co.,Ltd.;

    The physicochemical properties of coal-based nano carbon-hydrogen fuel with different particle sizes were analyzed by means of synchronous thermal analyzer, calorimeter, surface tension tester and viscosity tester.Studied the changes in physical properties such as viscosity, density, and surface tension of liquid fuels under the influence of conventional coal water slurry and nanoparticles, as well as the pyrolysis behavior of different particle sizes of nano carbon hydrogen fuels.The results show that the relative density, viscosity and surface tension of the nano carbon-hydrogen fuel slurry gradually increase with the increase of the degree of nano crystallization, and the slurry has good anti agglomeration performance and shear thinning characteristics. The TG-DSC experiment shows that, compared to conventional coal-water slurry, the heat released by the slurry of 0.8—1.2 μm(excluding mineral conversion) has increased by about 20%,providing a basis for the empowerment of the coal powder nanoparticle process.

    2024 S2 v.30 [Abstract][OnlineView][Download 1125K]

  • Efficient extraction of silicon and aluminum from fly ashbased on double response surface method

    ZHAO Jiajia;ZHAO Mengjie;PANG Shujun;LI Jian;SHI Yingjie;LI Jun;DENG Shuang;HUANG Jiayu;Air Pollution Control Research Center,China Academy of Environmental Sciences;School of Chemical and Environmental Engineering,China University of Mining and Technology ( Beijing );Selection Research Institute, Jiangxi Copper Technology Research Institute Co.,Ltd.;China Environmental Protection Industry Development Center;

    How to efficiently and cooperatively extract Si and Al components from fly ash to provide raw materials for high-value utilization of fly ash is one of the key problems facing urgent solution. By means of single factor test, response surface method and characterization techniques such as ICP-OES, XRF and XRD, the influence of leaching acid concentration, leaching time and leaching temperature on the leaching rate of Si and Al, the single index leaching mathematical model of Si and Al and the collaborative leaching mathematical model of Si and Al were studied in this paper. The surface optimization results show that when the leaching temperature is 68.57 °C, the leaching time is 120 min and the hydrochloric acid concentration is 8.63 mol/L, the leaching rate of Al can reach 95.27%, and the percentage content of SiO_2 in the extract can reach 93.15%.The influencing factors of silicon and aluminum dissolution rate: leaching temperature > acid concentration > leaching time, among which the interaction between acid concentration and leaching temperature has obvious effects on the leaching of silicon and aluminum, while the interaction between leaching temperature and leaching time has little effect on the leaching rate of Al, and has a greater impact on the dissolution of SiO_2. This research method and test results can provide a theoretical reference for the simultaneous and efficient dissolution of silicon and aluminum in fly ash.

    2024 S2 v.30 [Abstract][OnlineView][Download 4347K]

  • Migration characteristics and immobilization of arsenic and lead during the leaching process of fly ash

    WANG Xiaobing;LI Hao;QU Wentao;ZHOU Lingmei;Kunlun Digital Technology Co.,Lt.;School of Chemistry and Environmental Engineering, China University of Mining and Technology-Beijing;

    In order to study the migration characteristic of trace harmful elements during the leachingprocess of flyash and the immobilization effect of immobilization agents on elements, the arsenic and lead ofraw coal and fly ash from a certaincoal chemical base were selected as research objects, sequential chemical extraction was usedto study the modes of occurrence of elements. The effects of pH and leaching time on element migration were studied in the leaching experiment. Finally, humic acid and zeolite were selected to studytheir immobilization effects on elements in fly ash. The results show that the insoluble mode was themain mode of occurrence of arsenic and lead in fly ash, while the insoluble mode, organic-bound mode andFe-Mn oxide-bound mode were their main modes of occurrence in raw coal. The risk assessment code methodindicated that arsenic and lead in raw coal and arsenic in fly ash were in the low-risk range. Themain reason why the maximum migration ratio, stage migration ratio and migration intensity of arsenic and lead in fly ash were lower than those in raw coal was that the due to insoluble mode was their main mode of occurrence in fly ash. Humic acid andzeolite had anobvious immobilization effect on arsenicand lead in fly ash, and the larger the amount of the agent, the lower their migration ratio. Humicacid had a better immobilization effect on arsenic than zeolite, while the two agents had a similarimmobilization effect on lead.

    2024 S2 v.30 [Abstract][OnlineView][Download 2048K]

  • Effect of low carbon olefins on Fischer-Tropsch Synthesis

    ZHANG Fengbo;FAN Jing;MENG Xiangkun;MEN Zhuowu;National Institute of Clean-and-Low-Carbon Energy;China Chemical Technology Research Institute;

    In the Fischer-Tropsch synthesis reaction, some of the generated olefin will re-adsorb on the catalyst active site for a secondary reaction, which has a certain influence on the Fischer-Tropsch synthesis reaction and its product distribution. The effect of different concentrations of low carbon olefin on Fischer-Tropsch synthesis was studied in a stirred-tank reactor over a precipitated iron catalyst. The results show that the addition of low carbon olefins have evident impact on both the conversion and product selectivity of Fischer-Tropsch synthesis, resulting in a decrease in the conversion of carbon monoxide, a slight increase in the selectivity of carbon dioxide, and a slight decrease in the selectivity of methane. The addition of low carbon olefin significantly changed the selectivity of low carbon hydrocarbons in the product, resulting in a significant increase in the selectivity of low carbon alkanes and a significant decrease in the selectivity of low carbon olefins. The effect of ethylene on Fischer-Tropsch synthesis was significantly stronger than that of propylene.

    2024 S2 v.30 [Abstract][OnlineView][Download 202K]

  • Simulation and analysis of water gas shift process coupled with dry feed coal gasification and green hydrogen

    WANG Zhaocheng;LI Fanrong;XIAO Dunfeng;Wuhuan Engineering Co.Ltd.;

    The pulverized coal gasification technology has been extensively implemented within the modern coal chemical industry. Nevertheless, due to the characteristics of high carbon monoxide content and high water content in the crude coal gas produced by pulverized coal gasification, existing water gas shift technologies are confronted with certain difficulties, such as high energy consumption, operational complexities, and low reliability during the processing of this type of crude coal gas. With the proposal of the Dual Carbon Target,the coupling of renewable energy and coal chemical industry has become one of the important means of carbon dioxide emission reduction. In order to solve the problems in the existing water gas shift technologies and combine the concept of renewable energy and coal chemical coupling, a water gas shift process coupled with dry feed coal gasification and green hydrogen was established. Initially, chemical simulation software Aspen Plus was utilized to model the process flow. Subsequently, the Design Specs tool was employed to set the inlet temperatures of the first and second shift reactors and the dry-basis molar concentration of carbon monoxide at the inlet of the first shift reactor. After that, simulation calculations of the entire process flow were conducted. Finally, sensitivity analysis was performed to examine the impact of carbon monoxide concentration on the reaction temperature and the influence of carbon monoxide conversion rate on consumable resources(steam and low-grade waste heat) and operating costs. This analysis aimed to obtain preferred operating parameters. Analysis results reveal that when the dry-basis molar concentration of carbon monoxide in the crude gas is 71.17%,the dry-basis molar concentration of carbon monoxide in the gas at the inlet of the first shift reactor should be limited to below 48.40%. As the conversion rate of carbon monoxide enhances, the output of high-quality medium pressure superheated steam was significantly reduced, while the output of low-quality waste heat was significantly increased. Moreover, operating costs gradually escalate as the conversion rate of carbon monoxide grows. When the conversion rate of carbon monoxide advances from 96.98% to 98.23%,the conversion rate of carbon monoxide rises by only 1.35%,but the operating cost increases by 10.97%.The analysis results show that when the dry-basis molar concentration of carbon monoxide in the crude gas is 71.17%,the dry-basis molar concentration of carbon monoxide in the gas at the inlet of the first shift reactor should be controlled below 48.40%. As the conversion rate of carbon monoxide increases, the output of high-quality medium pressure superheated steam decreases significantly, and the output of low-quality waste heat increases significantly. The operating cost gradually increases as the conversion rate of carbon monoxide increases. When the conversion rate of carbon monoxide increases from 96.98% to 98.23%,the conversion rate of carbon monoxide increases by only 1.35%,but the operating cost increases by 10.97%. Therefore, when the conversion rate of carbon monoxide is at a high level, it is advantageous to produce more medium pressure superheated steam as a by-product, thereby enhancing the heat utilization efficiency and reducing operating costs. For the overall process simulation, the dry-basis molar concentration of carbon monoxide in the gas at the inlet of the first shift reactor is recommended to be 48.40%,and the conversion rate of carbon monoxide is set at 96.98%. The results reveal that after a two-stage shift reaction, the dry-basis molar concentration of carbon monoxide in the crude gas can be reduced from 71.17% to 0.99%.

    2024 S2 v.30 [Abstract][OnlineView][Download 329K]

  • Compressive properties and microscopic characterization of solid waste matrix coal gangue concrete

    FAN Donglin;Shendong Coal Technology Research Institute;

    In order to accelerate the resource utilization of coal gangue and meet the strategic requirements of carbon neutralization, the solid waste cementitious coal gangue road stabilization material was prepared by alkali excitation principle. In this study, uniaxial compression tests were carried out on the stable materials of solid waste matrix cemented coal gangue concrete under different conditions, and the structural characteristics of coal gangue concrete materials were analyzed from the micro level by means of SEM,EDS and XRD. The results show that with the increase of alkali dosage, the compressive strength of the sample increases gradually. With the increase of water-binder ratio, the compressive strength of the sample increases first and then decreases. With the increase of bone glue ratio, the compressive strength of the sample increases first and then decreases. When the alkali content is 7 %,the water-binder ratio is 0.4,and the bone-binder ratio is 0.8,the compressive strength of the solid waste matrix cemented coal gangue concrete stabilized material reaches the maximum;according to the microscopic test, it is found that when the solid waste matrix is cured to 28 d, the amorphous ecological gel coagulation product formed by the reaction of the solid waste matrix in the alkaline environment is filled between the coal gangue granular skeleton particles, and a large number of polymerization products are accumulated to form a honeycomb network topology. The research results can provide theoretical basis for coal gangue concrete paving roadway floor in underground roadway.

    2024 S2 v.30 [Abstract][OnlineView][Download 1147K]

  • Study on microwave drying and energy consumption characteristics of sludge intensified by coal slime

    WANG Guangyu;ZHANG Kaihua;ZHANG Kai;Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation,North China Electric Power University;

    As a microwave absorber, coal slime can achieve low energy consumption and rapid drying of sludge. Through a self-built microwave drying device, the influence of coal slime addition on sludge microwave drying rate and dehydration energy consumption is studied, and the dynamic mechanism of adding coal slime to strengthen microwave drying of sludge in the constant-rate drying stage and the decreasing-rate drying stage is analyzed in depth. The results show that under 500 W,coal slime with a mixing ratio of 0 to 30% can significantly shorten the total drying time and greatly increase the dehydration rate. Due to the high dielectric constant of coal slime, the coal slime and sludge mixture can absorb more microwave energy, and the residual alkali metals and alkaline earth metals in the coal slime will form a hot spot effect, further increasing the drying rate of the mixture. As a result, the total time required for complete drying of 200 g of sludge is shortened from 42.3 min to 27.6 min, and the dehydration rate in the constant-rate stage is increased from 0.021 g/(g·min) to 0.031 g/(g·min),which is 14.2 %(10%) ～ 47.6%(30%) higher than the original sludge. After coal slime and sludge are mixed, the dehydration energy consumption in the constant-rate drying stage is the lowest, which is much lower than the preheating stage and the decreasing-rate drying stage. Adding 0～30% coal slime can reduce the dehydration energy consumption of the original sludge in the constant-rate drying stage from 8.20 kJ/g to 6.92 kJ/g(mixing ratio 30%). Under the 500 W,the dehydration energy consumption increases with the increase of coal slime mixing ratio. By comparing the five kinetic models, the Linear model can effectively describe the kinetic processes in the constant-rate stage, and the modified Page I model is suitable for describing the decreasing-rate stage. The addition of coal slime can increase the slope of the constant-rate stage of the original sludge from 0.032 min~(-1) to 0.048 min~(-1),and the rate constant k of the decreasing-rate stage increases from 0.041 min~(-1) to 0.056 min~(-1).

    2024 S2 v.30 [Abstract][OnlineView][Download 1010K]

  • Study on fast pyrolysis behavior of Xinjiang coal based on TG-FTIR and Py-GC / TOF-MS

    CAO Yuemei;AN Xiaoxi;SHI Jungao;LIU Shaojiang;ZHAO Qiang;Shandong Lujian Safety Technology Co.,Ltd.;Shandong Jinfeng Technology Development Co.,Ltd.;Shandong Dingxin Energy Engineering Co.,Ltd.;

    In order to explore the pyrolysis characteristics of raw coal under the condition of high heating rate, the precipi-tation law and composition of fast pyrolysis products. Taking Xinjiang coal as the experimental object, the ex-perimental research was carried out by using thermogravimetric infrared spectrometer(TG-FTIR) and rapid py-rolysis instrument combined with gas chromatography tandem mass spectrometry(Py-GC/TOF-MS) reaction equipment. The results show that the pyrolysis of Xinjiang coal is mainly divided into four stages. The main py-rolysis stage is at 390—600 ℃,which corresponds to a significant decrease in the TG curve, and the DTG curve shows the maximum weight loss rate in this temperature range. There is a linear growth relationship between heating rate and pyrolysis characteristic parameters. Infrared spectroscopy showed that the main volatile substances were CO_2,CO,CH_4,C_2H_4,light hydrocarbons, C-O bonds and C=O bonds. With the increase of heating rate, the relative content of volatile substances also gradually increased. Coal pyrolysis products mainly include alkanes, olefins, aromatic compounds and phenols. The production of volatile substances increased with the increase of pyrolysis temperature and residence time, and decreased with the increase of heating rate. The relative content of pyrolysis products is higher for olefins and aromatic compounds. The expe-rimental results provide a theoretical basis for the development of coal fast pyrolysis reactor and the acquisition of high value-added chemicals.

    2024 S2 v.30 [Abstract][OnlineView][Download 1309K]

  • Research and engineering application on the influence of large-scale direct coupled biomass in pulverized coal boiler

    LIU Guangpeng;ZENG Jie;RAN Shenming;LI Xiaorong;ZHANG Xiuchang;GUO Guangliang;Clean Combustion and Flue Gas Purification Key Laboratory of Sichuan Province;Dongfang Boiler Co.,Ltd.;

    As an important clean energy source, using biomass mixed with coal or pure combustion can help reduce CO_2 emissions. By calculating the coupling ratio of wheat, corn, rice, asparagus, and wood in a 660 MW supercritical opposed coal-fired boiler, with a coupling ratio of 0-50%,and combining with experimental data of a certain boiler unit's direct combustion coupled biomass, the impact of coupling combustion on boiler operating parameters is analyzed, including flue gas volume, theoretical combustion temperature, furnace outlet flue gas temperature, air preheater outlet flue gas temperature, pollutant emissions, the impact of fly ash combustibles and boiler efficiency. The results showed that the amount of smoke generated by co-fired wheat, corn, and asparagus increased, the theoretical combustion temperature decreased, while the trend of co-fired rice and wood were opposite. When the blending ratio reaches 50%,the amount of flue gas from asparagus increases by 8.87%,which may require modification of the original induced draft fan system. The theoretical combustion temperature of mixed burning of asparagus decreased by 146 ℃,and rice and wood increased by 48 ℃ and 54 ℃ respectively. Therefore, asparagus is more suitable for high sulfur coal boilers with severe high-temperature corrosion, and rice and wood are more suitable for lean coal and anthracite boilers with large unburned carbon loss. As the biomass coupling ratio increases, the flue gas temperature at the furnace outlet decreases, but the decrease is not significant. Among them, the coupling wood decreases the fastest, and the 50% blending ratio only decreases by 17 ℃. Due to the reduced amount of cold air entering the air preheater for heat exchange, the outlet flue gas temperature of the air preheater has increased by 19-38 ℃,and the boiler thermal efficiency has decreased by 1.18%-2.5%. While ensuring safety, the conveying air temperature of biomass should be increased as much as possible. The low sulfur content of biomass leads to a decrease in SO_2 emissions after coupled combustion, but NO_x emissions are related to fuel composition, furnace oxygen content, and combustion organization. During the transformation, the feeding location of biomass needs to be selected based on the specific situation of the boiler. Measures such as optimizing the boiler combustion system, reforming the heating surface, and utilizing waste heat can be taken to meet the demand for a large proportion of direct combustion coupled biomass in coal-fired boilers. When blended with 40 t/h of biomass fuel, it is expected to reduce 270 000 tons of CO_2 annually.

    2024 S2 v.30 [Abstract][OnlineView][Download 323K]

  • Heat transfer characteristics of wheat straw particle during fixed bed pyrolysis

    CHEN Na;GUO Yun;School of Mechanical and Automotive Engineering,Shanghai University of Engineering Science;

    The internal heat transfer within wheat straw particles is essential to the pyrolysis yield(bio-oil, combustible gas, coke) and energy consumption of wheat straw. To investigate this pyrolytic property, first investigates the shape of wheat straw particles after crushing and the results show a very pronounced platy structure, especially in the particle size range of 3-20 mm. Therefore, a thin rectangular model is more appropriate to describe the wheat straw particle. On this basis, a mathematical model of heat transfer during pyrolysis of wheat straw particle is developed. In addition, the heat transfer model is used to predict the temperature and heating time of the center of wheat straw particle of different sizes at different heating rates. The results of the calculations show the importance of platy structural features for heat transfer processes as well as for particle fragmentation. Finally, the residence time of the wheat straw in the pyrolysis reactor is slightly greater than the heating time of the wheat straw particle is important to improve the efficiency of the pyrolysis and decrease energy consumption.

    2024 S2 v.30 [Abstract][OnlineView][Download 267K]

  • Field experimental study on mixed combustion of domestic sludge in 350 MW supercritical CFB boiler

    LI Debo;QUE Zhengbin;CHEN Jian;MIAO Jianjie;CHEN Tuo;CHEN Zhihao;CHEN Zhaoli;China Southern Grid Power Technology Co.Ltd.;National Engineering Laboratory of Biomass Power Generation Equipment,North China Electric Power University;Shaoguan Yuehua Power Co.Ltd.of Guoyue Group;College of Power Engineering,North China Electric Power University;

    The technology of mixing domestic sludge in coal-fired boiler has the advantages of harmless disposal of sludge, recovery and utilization of sludge heat, promoting the clean and low-carbon development of coal and power industry, and has a broad development prospect. At present, the main types of domestic sludge mixed combustion in coal-fired power plants are pulverized coal boilers and CFB boilers, but the research on CFB boilers is relatively few. In order to explore the combustion efficiency and environmental protection characteristics of supercritical CFB boilers mixed with domestic sludge, field tests were carried out on 14 load conditions of 180,260 and 350 MW boilers based on two 350 MW supercritical CFB boilers in a power plant in China. The research results show that the mixed burning of sludge has no effect on the original production system of the power plant. When the mixed burning ratio is 5% to 15%,the operation of each system of the boiler is stable, all the parameters are in the normal range, and the change of boiler efficiency is basically about 0.5%. The emission of flue gas pollutants meets the requirements of environmental protection, and the power plant can operate normally. Although the boiler efficiency shows a downward trend with the increase of sludge blending ratio, and the lower the boiler operating load is, the greater the decline is, but the overall effect of sludge blending on boiler efficiency is smaller, and the maximum reduction of boiler efficiency under the same load test condition is less than 0.5%. Aiming at three kinds of conventional flue gas pollutants: NO_x,SO_2 and dust, the data provided by CEMS device can be used as the research basis in the test process. It is found that the flue gas mixed with burning sludge can still meet the ultra-low emission requirements of coal-fired power plants through the existing purification system, and there is no need for transformation and upgrading. For the two unconventional flue gas pollutants, heavy metals and their compounds and dioxins, although there is no special removal device, it is found that the impact is small when the proportion of mixed combustion is low, so it can be disposed of normally and will not cause secondary pollution.

    2024 S2 v.30 [Abstract][OnlineView][Download 169K]

  • Common problems analysis and optimization design of SCR denitration urea hydrolysis ammonia production process

    DENG Yue;China Datang Northwest Electric power test and Research Institute;

    In view of the common problems of SCR denitration in coal-fired units, a set of intelligent multi-point sampling system is designed, including double-tube sampling system, air-cooling unit system and flow balance unit, and is tested and applied in 350 MW units. The results show that the average concentration of the section measured by the SCR intelligent multi-point sampling system is representative, can meet the accuracy requirements of operation monitoring and environmental protection monitoring, and ensure the timeliness and accuracy of the measured data, The NO_x concentration signal at the SCR outlet can be fed back to the ammonia injection operation control of the unit in advance, which can effectively alleviate the problems that affect the safe and economic operation of the unit, such as large deviation of NO_x concentration distribution at the reactor outlet, high local ammonia escape and blockage of the air preheater in the SCR denitration system.

    2024 S2 v.30 [Abstract][OnlineView][Download 822K]

  • Modeling coal consumption of supercritical thermal power units based on multilayer perceptron neural network

    JIANG Jian;GONG Jun;XU Bingchao;ZHANG Qi;ZHU Hengyi;TAN Peng;ZHANG Cheng;Guangdong Hongwan Power Generation Co.;School of Energy and Power Engineering,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) is proposed, which integrates the coupling influence relationship between boiler-side and steam engine side parameters on coal consumption. A 660 MW supercritical thermal power unit is used as the modeling object, and 54 main operating parameters are 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 are used for model training and the remaining 20% are used for model validation. The model training uses EarlyStopping technique 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 were between ±0.325 g/(kW·h),of which 62.22% and 61.22% were in the range of ±0.25 g/(kW·h),respectively. The MLP can replace the mechanism model for coal consumption calculation and lay the foundation for online real-time optimization.

    2024 S2 v.30 [Abstract][OnlineView][Download 961K]

  • Effect of melamine on the distribution of tar products from co-pyrolysis of Zichang coal

    LI Qiulin;WANG Yulu;ZHOU Qiucheng;LUO Ziteng;ZHANG Junxing;YANG Mengna;HE Yifan;ZHOU Anning;CHEN Fuxin;Xi'an University of Science and Technology;Northwest University;Shanxi Yanchang Petroleum (Group)Co.Ltd.Hydrocarbon High-Efficiency Utilization Technology Research Center;

    To investigate whether the co-pyrolysis of nitrogen-containing compounds with coal can produce nitrogen-rich tar, melamine was co-pyrolyzed with sub-changing coal, and the suitable thermal cracking temperature was screened by thermogravimetric screening, and under the optimized conditions, the tar was prepared and enriched using a fixed-bed, and the rule of change of the distribution and content of the coal-tar product was investigated by GC/MS,1D NMR and 2D NMR. The results showed that the nitrogenous compounds in the co-pyrolysis tar increased from 6% to 23%,which was about three times; phenolics decreased from 17% to 10%;and thick cyclic aromatic hydrocarbons decreased from 22% to 12%. It is speculated that there is a certain synergistic effect between coal and melamine in the process of co-pyrolysis, and the N element enters into the tar product through the free radical exchange in the pyrolysis process, and the introduction of melamine decreases the content of polycyclic aromatic hydrocarbons, and the nitrogen radicals it produces generate nitrogen-containing compounds or amines through the substitution or cyclization reaction, which indirectly reduces the condensation of monocyclic and thick-cyclic aromatic hydrocarbons, and realizes the directional control of nitrogen-rich tars to a certain degree, and provides a good opportunity for the high-value utilization of coal resources provides a reference.

    2024 S2 v.30 [Abstract][OnlineView][Download 1877K]

  • Numerical simulation and transformation effect analysis of SCR denitration system under non-uniform boundary conditions

    GUO Lei;HUANG Liming;WEI Zhenzu;LIU Ting'an;WANG Liang;WU Wei;China PowerHua Chuang (Suzhou) Electricity Technology Research Co.LTD;Anhui Huainan Pingwei Power Generation Co.LTD;Suzhou Xire Energy Saving and Environmental Protection Technology Co.LTD;

    Aiming at the problems of SCR denitration system of 640 MW unit in a coal-fired power plant such as large deviation of NO_x concentration monitoring data, large consumption of reducing agent, uneven flow field, severe catalyst wear and ash accumulation, etc, through the combination of numerical simulation and field engineering practice, from the top catalyst upstream gas velocity distribution, NH_3/NO_x molar ratio distribution, incidence angle, system pressure drop and other angles, the flow field and ammonia spray grille of SCR denitration system were optimized. Engineering verification was carried out, and the results showed that after the transformation, the NO_x concentration distribution at the SCR outlet maintained good uniformity, the NO_x and ammonia escape emissions reached the standard and were stable under different loads of the unit. This method can improve the smoke flow field distribution at SCR denitration inlet, catalyst wear, ash accumulation and ABS clog of air preheater, and can provide reference for similar units.

    2024 S2 v.30 [Abstract][OnlineView][Download 3688K]

  • Influence of boiler operation parameters on the performance of the closing-to-wall air system installed at front and rear wall

    YANG Lu;LIU Xiaodong;CHEN Guoqing;ZHANG Yong;China Energy Guoyuan Power Co.Ltd;State Key Laboratory of Low-carbon Smart Coal-fired Power Generation and Ultra-clean Emission China Energy Science and Technology Research Institute Co.Ltd;School of Energy and Environment,Southeast University;

    Taking a 1 000 MW ultra supercritical opposite firing boiler with closing-to-wall Air system installed at front and rear wall as the research object, the influence of closing-to-wall air system on the atmosphere closing to the side water-walls were analyzed, and the effect of boiler operation parameters on performance of closing-to-wall air system were studied. The results show that the reductive atmosphere closing to the side water-walls can be effectively improved by closing-to-wall air system installed at front and rear wall. However, there is still a high temperature corrosion risk in the middle area of the side wall, because the jet stiffness of the closing-to-wall air system is not rigid enough. The reductive atmosphere closing to the side water-walls in the middle area of side wallcan be effectively improved by increasing the total air volume and reducing the over fire air volume.It is not obvious to change the secondary air distribution and increase the primary air pressure on the performance of the closing-to-wall air system.

    2024 S2 v.30 [Abstract][OnlineView][Download 1011K]

  • Study on IGFC system control policy and model development

    LIU Changlei;LI Chufu;DONG Binqi;XU Ming;Guohua Energy Investment Co.,Ltd;National Institute of Clean and-low-carbon Energy;

    Integrated coal gasification fuel cell(IGFC) power generation is a revolutionary and frontier technology of coal based low carbon and efficient power generation, which can realize CO_2 enrichment while efficient power generation. The control policy of IGFC system is discussed, and the main control parameters and control methods of fuel cell power generation and exhaust pure oxygen combustion are proposed. The heat balance model of high temperature fuel cell power generation unit and the CO_2 concentration prediction model of pure oxygen combustion exhaust gas were established, and the relevant parameters of the model were obtained through experiments. Using the heat balance model of high-temperature fuel cell power generation unit, the relative error of stack voltage and power generation prediction is less than 5%,and the control values of main parameters of 20 kW high-temperature fuel cell power generation unit under different power generation are obtained. The combustion experimental verification of 20 kW IGFC power generation tail gas was carried out. Under the condition of low oxygen excess coefficient(1.05),the CO_2 dry basis concentration after pure oxygen combustion of the tail gas reaches more than 93%,and the prediction error with the tail gas CO_2 concentration model was less than 1%. Through the model prediction established, combined with conventional PID control, the key parameters of IGFC system can be effectively controlled.

    2024 S2 v.30 [Abstract][OnlineView][Download 325K]

  • Study on pollution emission characteristics and prediction of ashfusion temperatures of mixed combustion of various biomass and coal

    MA Hui;WANG Chaoyang;WANG Tianlong;YAN Huibo;HAN hui;QIN Zhiming;YANG Xianliang;LEI Ming;ZHANG Qian;ZHANG Lei;State Grid Hebei Energy Technology Service Co.,Ltd;Electric Power Research Institute of State Grid Hebei Electric Power Co.,Ltd;School of Energy Power and Mechanical Engineering,North China Electric Power University;

    The NO and SO_2 emission characteristics of straw, sludge and Chinese medicine slag mixed with lean coal were studied. Then, the ash fusion characteristics of the blended samples were analyzed, and the softening temperature was predicted by machine learning algorithm. The results show that when the raw material is burned alone, the emission curves of NO and SO_2 in lean coal show a bimodal structure, and the complete discharge time is longer. However, the emission curves of NO and SO_2 in biomass combustion shows a single peak structure and the emission time is short. The conversion rate of NO and SO_2 in the mixture was reduced by biomass mixing compared with that of lean coal combustion alone. The slagging risk of lean coal and Chinese medicine slag is low, while the slagging risk of straw and sludge is high. The straw has little effect on the softening temperature of the mixture, the slagging risk is low, while the mixing of Chinese medicine residue will significantly decrease the softening temperature of the mixture, the risk of slagging is increased. Among the selected algorithms, decision tree regression model is more accurate in predicting the softening temperature of ash.

    2024 S2 v.30 [Abstract][OnlineView][Download 342K]

  • Combustion characteristics and feasibility of W-type flame boiler changing from blended coal to bituminous coal as fuel

    XIONG Hui;WU Yuanyuan;MAO Zhihui;SONG Gongxiang;JIANG Long;HU Song;XIANG Jun;Hubei Energy GroupEzhou Power Generation Co.,Ltd.;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

    In order to investigate the feasibility of the 330 MW W-type flame boiler in Ezhou Power Plant changing from blending 40% bituminous coal to 100% bituminous coal, thermodynamic calculation and numerical simulation of burning 100% bituminous coal were carried out. The safety and stability of the W-type flame boiler were evaluated based on the furnace outlet flue gas temperature, component concentration and other indicators to determine the adaptability of burning 100% bituminous coal. The results show that in the case of W-type flame boiler burning 100% bituminous coal, the furnace outlet flue gas temperature increase by 10 ℃ compared to the design condition. Removing most part of the refractory belt will reduce the outlet flue gas temperature by about 20 ℃,which effectively ensure that outlet flue gas temperature is lower than the design value. Eliminating the exhaust air and increasing the primary air ratio have great benefit in reducing the risk of burner burnout and furnace coking. The burning of 100% bituminous coal led to the increase of the nitrogen content in the fuel as well as the flame temperature. The NO_x concentration at the furnace outlet increases from 640 mg/m~3 to 720 mg/m~3 under the circumstance of not removing the refractory belt. The removal of 100 m~2 refractory belt on the side wall of the lower furnace can reduce flame temperature, thus inhibiting the generation of thermal NO_x and reducing NO_x outlet concentration to 480 mg/m~3.

    2024 S2 v.30 [Abstract][OnlineView][Download 385K]

  • Effect of RDF gas reburning on operation performance of coal-fired boilers and SCR denitrification

    WANG Aijun;BAI Linrui;ZHOU Cheng;YANG Maoquan;ZHANG Xiaotao;School of Energy and Power,North China University of Water Resources and Electric Power;

    With economic development, urban waste disposal issues have become increasingly severe. The use of Refuse Derived Fuel(RDF) gasification coupled with coal co-firing technology can environmentally treat waste and reduce emissions of pollutants from coal-fired furnaces. In order to analyze the operational performance of a coal powder furnace coupled with RDF gasification and its impact on Selective Catalytic Reduction(SCR) denitrification, a model was constructed based on a 600 MW coal-fired boiler. The model integrated the model of RDF gasification coupled coal-fired boiler staged re-ignition system and SCR denitrification system. Three types of RDF and Yima bituminous coal were selected as fuels, and combustion processes were simulated at different co-firing ratios. The results show that RDF gasification and co-firing led to an increase in the furnace outlet temperature and flue gas temperature, causing a decline in boiler efficiency. However, the NO_x emissions in the flue gas decreases, and this reduction becomes more significant with an increase in the co-firing ratio. The methane(CH_4) content in RDF gas influences the denitrification effect. Among the three RDF gasification conditions, RDF 2 has the highest CH_4 content after gasification, resulting in the best denitrification effect. At a co-firing ratio of 20%,the NO_x emissions in the flue gas decreases from 36.34 mg/m~3 in the original pure coal combustion condition to 30.02 mg/m~3,representing the highest emission reduction. When the ammonia injection rate is constant, the change of SCR denitrification efficiency shows different increasing and decreasing trends with the increase of recombustion blending ratio. Under the RDF 1 and RDF 2 co-firing conditions, the SCR denitrification efficiency increases with the increase in co-firing ratio, reaching a maximum from 89.89% to 90.91%. RDF 3 co-firing has a relatively small impact on denitrification efficiency.

    2024 S2 v.30 [Abstract][OnlineView][Download 1001K]

  • Safety analysis of coal gasifier ignition based on the dow chemical method

    ZHANG Youjun;YANG Honghui;HAO Jun;HUANG Anlong;ZHANG Zheng;CHEN Long;Jianghan Machinery Research Institute Limited Company of CNPC;Wuhan Sanjiang Aerospace Distant Technology Co.Ltd;

    The ignition process of coal gasification involves dangerous conditions, such as high temperature, high pressure, and inflammable/explosive substances, which necessitates meticulous safety design analysis. In this study, the Dow Chemical Method was employed to conduct such a safety analysis. The results demonstrated that through implementation of stringent safety control measures, the risk level of propane could be reduced from "very large" to "low",that of triethylborane from "very large" to "medium",and that of silane from "very large" to "medium". Consequently, the safety risks associated with the process became within a controllable range. The adopted safety measures could significantly mitigate the risk of accidents. The research findings could provide valuable guidance for the safety analysis of other coal gasification equipment, ensuring the overall safety and reliability of the system from its design to operational stages.

    2024 S2 v.30 [Abstract][OnlineView][Download 440K]

  • Exploration of ultra-low load deep peak sharing capability of coal-fired porver turbine

    HE Guangxun;ZHU Haiyi;LIU Xin;YU Haipeng;SUN Jia;GUAN Chun;LI Bo;LIU Yilin;Harbin Eleceric Power Generation Equipment National Engineering Research Center Co.,Ltd.;

    Based on the target requirements of flexible transformation and manufacturing under the " Interaction of Three Reforms " mode in the national implementation plan for the coal-fired power units transformation and upgrading,in order to effectively improve the flexibility of steam turbine equipment in coal-fired power stations and achieve long-term safe and stable operation during ultra-low load deep peak-shaving of steam turbines, the author has carried out the ultra-low load thermal simulation integrated calculation for the 300～1 000 MW typical capacity coal turbine and its auxiliary equipment, and completed the systematic evaluation of the operation state of the whole machine under the deep peak-shaving mode and the comprehensive analysis of the safety risk generation mechanism of the last two stages of long blades under low load. Based on the calculation, evaluation and test of the dynamic stress level of long blades, this paper verifies the effectiveness of blade vibration resistance strengthening measures to solve the vortex-induced effect and dynamic stress risk of long blades. At the same time, in view of the safety risks existing in the ultra-low load operation of the steam turbine, this paper puts forward the technical reform measures that need to be applied together, gives the requirements for the deep peak-shaving test and engineering operation of the steam turbine, and finally demonstrates the engineering feasibility of the deep peak-shaving of the full capacity coal turbine with hard load reduction to 15%～20% THA.

    2024 S2 v.30 [Abstract][OnlineView][Download 2807K]

  • Study on the influence mechanism of coal mixed with straw and sludge on ash melting characteristics

    YU Xu;SUN Hao;ZHANG Tao;CHENG Zhenyu;YAN Deya;Yancheng Thermal Power Co.,Ltd.;Shanghai Power Equipment Research Institute Co.,Ltd.;

    Burning sludge or straw together with coal in power plants not only effectively reduces pollution but also promotes the reuse of resources. In order to study the influence of co-firing coal with sludge or straw on the fusibility of ash, experiments were conducted using a muffle furnace at a temperature of 950 ℃,with coal powder mixed with 8% mass fraction of sludge or straw. The obtained ash was characterized by SEM-EDS to explore the mechanism of different additives on the fusibility of ash. The results show that the addition of straw or sludge makes the resulting ash more prone to sintering, reduces the melting temperature of ash, decreases the amount of fine surface deposits, and increases the number of pores. Additionally, this study investigates the effect of temperature on the mineral transformation of ash, by conducting ashing experiments on the samples at temperatures of 500 ℃,700 ℃,and 900 ℃,followed by XRD analysis. The results indicate that with increasing temperature, the XRD spectra of samples containing straw and sludge tend to be consistent, suggesting that the influence of adding straw and sludge on the types of minerals in coal ash is relatively small.

    2024 S2 v.30 [Abstract][OnlineView][Download 2183K]

  • Simulation study on the influence of sludge coupling power generation on circulating fluidized bed boiler system based on Aspen Plus

    SHI Wan;LI Xiaojiao;YUAN Jin;ZHOU Yinxi;YU Li;JI Wei;PENG Ya;College of Environmental Science and Engineering,Taiyuan University of Technology;Innovation Institute of Environmental Protection Industry,Taiyuan University of Technology;

    To explore the influence of sludge coupled power generation on the performance of Circulating Fluidized Bed Boiler, a 480 t/h circulating fluidized bed boiler in a power plant was taken as the research object, and the whole process was simulated by Aspen Plus, and the simulation results were compared with the design parameters to verify the accuracy and reliability of the model. Adding sludge stream to circulating fluidized bed boiler model can simulate the influence of sludge coupled power generation on theoretical combustion temperature, furnace volume heat load, flue gas flow rate, flue gas composition and boiler thermal efficiency. The results show that when the ratio of sludge to combustion is 6%,the theoretical combustion temperature of the furnace is 15.5 ℃ lower than that without sludge, which has little influence on the combustion in the furnace. The flue gas flow rate at the outlet of economizer increases by 2.50%,and the cubic ratio of flue gas flow rate is 1.069,which shows that the mixed combustion of sludge has little influence on the wear of boiler heating surface. The water vapor content in flue gas increased obviously when sludge was mixed with combustion, but the other components did not change obviously. At this time, the boiler thermal efficiency was 88.84%,which was 0.25% lower than that when sludge was not mixed with combustion. In a word, when the proportion of mixed combustion is less than 6%,sludge coupling power generation has little influence on boiler performance.

    2024 S2 v.30 [Abstract][OnlineView][Download 3563K]

  • Numerical simulation of optimization of flue gas recirculation low nitrogen burner based on JL combustion mechanism

    ZHANG Yupeng;YANG Jinglan;SI Peizhuang;LIU Xiaolin;GUO Changjing;WEI Ren;HAN Fenglei;College of Chemistry andChemical Engineering,China University of Petroleum (East China);PetroChina Guangdong Petrochemical Company;

    With the increasingly stringent emission standards of boilers, NO_x has become a major concern of natural gas boilers. It is urgent to transform the original boilers to achieve ultra-low NO_x emission. In order to provide theoretical support for the rational design of burner, based on a natural gas low nitrogen burner combined with flue gas recirculation(FGR) and fuel staging technology, the NO_x emission law was explored by using the method of numerical simulation and experimental comparative study. The physical model of burner and furnace was built. Based on the four step mechanism of JL-2 methane combustion and combined with the five step nitrogen oxide mechanism, the experimental values under actual load conditions were simulated and verified, and the NO_x emission concentration was reduced by two thirds under the action of FGR. The influence of structural parameters on the flame structure and NO_x emission concentration was studied. It was found that the change of burner structure on the flame structure and the area of flame high temperature zone was the reason for the change of NO_x concentration. Through orthogonal test and range analysis, it is found that the structural factor of side opening width has the most significant effect on NO_x emission

    2024 S2 v.30 [Abstract][OnlineView][Download 3035K]

  • Analysis and countermeasures of water-cooled wall leakage of supercritical boiler

    MA Fei;CHEN Heng;Hebei Zhuozhou Jingyuan Thermal Power Company Ltd.;North China Electric Power University;

    The main function of boiler water-cooled wall is to conduct the heat at high temperature and high pressure to ensure the normal operation of the boiler. However, during operation, due to the harsh working environment of the water-cooled wall, it is subject to factors such as high temperature and pressure corrosion, water quality pollution, and other factors for a long time. Therefore, its leakage accidents have always been a key issue in power plant operation. In recent years, with the continuous improvement of power plant technology and the upgrading of boiler equipment, the problem of water-cooled wall leakage has been well controlled. However, under certain special circumstances, there is still a risk of water-cooled wall leakage. For example, high-temperature corrosion can cause thinning of the water-cooled wall steel pipe, thereby reducing its ability to withstand pressure; water-cooled wall over-temperature can cause pipe expansion, leading to pipe deformation and fracture; water-cooled wall wear may cause the inner wall surface of the pipe to lose protection, further aggravating corrosion and damage to the pipe. So, analyzing the causes of water-cooled wall leakage accidents is of great practical significance. Here, a water-cooled wall leakage incident of a thermal power company was investigated and analyzed for the cause of the accident using a comprehensive method of laboratory analysis and operating parameter analysis. It was confirmed that due to the improper operation of the construction personnel, when welding small-diameter pipes, toilet paper was used instead of water-soluble paper to block ventilation, which could not dissolve sufficiently and mixed with metal debris to block the pipeline, resulting in overheating of the pipe wall and pipe bursting in the short term. At the same time, feasible countermeasures were proposed for factors that may cause water-cooled wall leakage such as high-temperature corrosion, pipe wall over-temperature, and wear.

    2024 S2 v.30 [Abstract][OnlineView][Download 2773K]

  • Analysis oncarbon emission intensity of domestic waste incineration industry in China

    ZHANG Hao;HU Siyi;LI Xiaodong;Institutefor Thermal Power Engineering,Zhejiang University;

    Waste incineration power generation has become the mainstream waste treatment method in China. Under the background of carbon neutrality, the carbon emission of its industry has attracted more and more attention, but there is still a lack of systematic research. In this paper, China Certified Voluntary Emission Reduction(CCER) methodology is used to explore the main carbon emission sources of incineration plants, and all waste incineration plants operating in China in 2016 are accounted and counted, and the carbon emission level and intensity of waste incineration industry in China are recognized for the first time, and the carbon emission intensity of incineration plants in different regions and sizes is analyzed. The results show that CO_2 generated by waste incineration itself is the most important carbon emission source in incineration plants, but the proportion of different incineration plants is quite different. In 2016,the annual carbon emission of domestic waste incineration power generation industry in China was 18.35 million tons, and the average carbon emission intensity per ton of domestic waste incineration was 0.214 tons. However, due to the influence of waste characteristics and incineration technology, there were significant differences among different provinces, ranging from 0.122 to 0.273 tons. The carbon emission intensity of unit megawatt-hour on-grid electricity is 0.715 tons, which is lower than that of coal-fired power plants.

    2024 S2 v.30 [Abstract][OnlineView][Download 1586K]

  • Study on the formation mechanism of low temperature heating surface scale

    LIU Zhijie;ZHOU Peiyan;China Energy Yongzhou Power Generation Co.,Ltd.;North China Electric Power University;

    Sulfate can easily lead to ash hardening of the heating area at the tail of the boiler to form high-strength scale, which affects the safety and economy of the equipment. In order to clarify the mechanism of scaling, the scaling experiments of calcium sulfate and ammonium bisulfate were carried out, and the compressive strength and X-ray diffraction composition analysis of the scale samples were carried out. The thermodynamic equilibrium calculation was used to determine which gelled substances would scale. The results showed that the compressive strength of fly ash scale samples under the action of calcium sulfate and ammonium bisulfate increased to varying degrees, and the compressive strength increased with the increase of sulfate content. Experiments and thermodynamic equilibrium calculations show that calcium sulfate reacts with ash to form gypsum sulfate cementitious materials;under the action of ammonium bisulfate, fly ash reacts to form gypsum cementitious material, a large amount of ammonia sulfate and a small amount of potassium alum, which has a stronger scaling tendency.

    2024 S2 v.30 [Abstract][OnlineView][Download 1946K]

  • Simulation study on optimization of active air distribution condition of downdraft gasifier

    NIU Yi;ZHENG Xianrong;CUI Zhigang;Taiyuan University of Technology College of Electrical and Power Engineering;Key Laboratory of Clean and Efficient Combustion and Utilization in the Circulating Fluidized Bed;

    Taking downdraft fixed bed gasifier as the research object, this research based on OpenFOAM, studied the differences in pressure distribution, velocity field distribution, and residence time of gasifying agents under different air distribution modes which contains combined air distribution and double-layer air distribution. In the modeling process, the modified porous model and RNGk-e model was selected and solved using a solver designed specifically for the biomass porous media bed. The results show that the position of the lower air distribution outlet is the pressure increase position and its flow rate is positively correlated with pressure. The combined air distribution has a smaller pressure increase at 0～0.73 m and a more reasonable pressure distribution compared to the double-layer air distribution. The flow field in the gasifier presents multiple vortices, and the velocity distribution map has good symmetry, indicating that the swirl of the flow field in the gasifier is stable and continuous. The introduction of secondary air in the combined and double-layer air distribution modes increases the residence time of gasifying agents by 46.6% and 23.9%, respectively. The residence time of gasification agent in the combined condition is 18.3 % higher than that in the double-layer condition. The velocity of 0.60-1.20 m increases with the increase of the central pipe flow rate, and the maximum average velocity is 0.21 m/s. The pressure of 0-0.60 m increases with the increase of the lower pipe flow rate, and the maximum pressure is 38.9 kPa. The combined air distribution condition has the best flow state, with ideal gasification pressure and gasification agent residence time distribution. The active air distribution has certain flexibility, which is conducive to the full mixing of materials and gasification agents, and has certain guiding significance for the actual air distribution operation.

    2024 S2 v.30 [Abstract][OnlineView][Download 415K]

  • Study on air leakage characteristics and optimization adjustment of Dry-type slag removal system in a 660 MW coal-fired unit

    CHEN Hongxin;MA Tianting;FANG Xin;WANG Lu;MEI Zhenfeng;ZHU Jinyong;China Energy Investment Suqian Power Generation Co.,Ltd.;Xi′an Thermal Power Research Institute Co.,Ltd.;

    The dry-type slag removal system of coal-fired units used cooling air to cool the slag, and the actual cooling air volume at the bottom of the boiler was higher than the design value universally. The dry-type slag removal system of a 660 MW coal-fired unit was taken as the research object in this paper. The air leakage characteristics of the dry-type slag removal system were studied by experimental and numerical simulation methods. The optimization adjustment and verification test were carried out. Results showed that: the top and side cooling air dampers of the dry-type slag removal system were controlled extensively, which led to a significant deviation of the cooling air volume from the design value. The on-line monitoring and closed-loop control of the top cooling air damper could reduce the air leakage rate of the dry-type slag removal system. The optimization adjustment of the side cooling air damper could control the overall cooling air volume of the dry-type slag removal system reasonably. After optimization, under high load conditions, the air leakage rate of dry-type slag removal machine was reduced by 44.5% on average. The average exhaust fuel gas temperature was decreased by 3.6 ℃ and the boiler efficiency was increased by 0.40 percentage points.

    2024 S2 v.30 [Abstract][OnlineView][Download 249K]

  • Research on an efficient and cost-effective semidry flue gas desulfurization technology using limestone with high water content

    HUANG Hailiang;BAI Haolong;FU Liangliang;XU Guangwen;BAI Dingrong;Key Laboratory on Resources Chemicals and Material of Ministry of Education,Shenyang University of Chemical Technology;School of Chemical Engineering,University of Science and Technology Liaoning;

    Traditional semidry flue gas desulfurization(SDFGD) has been widely used in controlling SO_2 emissions from small and medium-sized coal-fired boilers and industrial furnaces. SDFGD offers low investment costs and ease of operation but suffers from high operating costs because of the use of expensive hydrated lime as the sorbent, especially when the sorbent utilization efficiency is low in some practical applications. To improve the desulfurization efficiency and economics, we proposed a new semidry flue gas desulfurization technology In this study. The technology uses inexpensive limestone(CaCO_3) with high water content as the sorbent to reduce the operating cost and increase the SO_2 removal efficiency. Under high sorbent water content conditions, the reaction between CaCO_3 and SO_2 is transformed from a low-rate gas-solid reaction dominated in SDFGD into a fast ionic reaction between Ca~(2+) and SO■ions. To validate the technical feasibility of this technology, we carried out experimental investigations of the reaction fundamentals in a lab-scale fixed bed reactor under 0-30% of the sorbent water content and 30-150 ℃ of flue gas temperature. The experimental results demonstrate that the desulfurization capacity of limestone sorbent increases with the increase of its water content. When the sorbent water content exceeds 25%,the desulfurization reaction becomes rate-controlled by the reaction between Ca~(2+) and SO_3~(2-)ions. Compared with conventional SDFGDs with a sorbent water content of less than 10%,when the sorbent water content is more than 25%,the desulfurization capacity of the sorbent increases 30-50 times, the sorbent utilization reaches 60%,and the sorbent cost is reduced by 30%-50%. The experimental work presented here provides an important opportunity to advance the understanding of flue gas desulfurization and the development of high-efficiency and low-cost flue gas desulfurization technology.

    2024 S2 v.30 [Abstract][OnlineView][Download 414K]

  • Improved calculation for boiler efficiency of CFB as fired oil shale base on ASME PTC 4

    CHEN Feng;LEI Li;State Grid Sichuan Integrated Energy Service Co.,Ltd.Power Engineering Branch;Si Chuan Electric Power Design & Consulting Co.,Ltd;

    As a supplement to conventional energy, oil shale(unconventional oil and gas resources) is of great strategic significance in changing China's energy structure. At the same time, it is listed as a very important alternative energy in the 21st century because of its rich resources and the feasibility of development and utilization. Compared with coal in conventional power plant, the oil shale is characterized by low calorific value, large ash content and large amount of CaCO_3 in ash. Although China is rich in oil shale resources(the fourth in the world),and only second to coal, oil shale is hardly well utilized, especially in the field of combustion power generation technology. Based on the ASME PTC 4(LHV) standard, an improved algorithm for the efficiency of oil shale circulating fluidized bed boiler is proposed, and the algorithm is applied through field tests, providing a reference for the subsequent domestic application of oil shale in power generation. The results show that: compared with the same type of coal-fired units, the sensible heat loss of ash in the combustion process of oil shale is significantly higher than 11.13%,the high ash content and low calorific value of oil shale cause the fuel fuel consumption ratio to be significantly higher, reaching 637.56 t/h, the CaCO_3 in the ash is not complete calcinations, and the heat absorbed less enters the boiler as external heat, resulting in the external heat value in the calculation of efficiency being significantly higher than 6.008%,the large amount of ash generated at the same time when the boiler efficiency reaches 91.97% can be comprehensively recycled. In addition to its rich resources and development feasibility, oil shale has high commercial application value in combustion power generation.

    2024 S2 v.30 [Abstract][OnlineView][Download 297K]

  • Optimization research of urea hydrolysis system under deep peak shaving in coal-fired power plants

    LIN Tingkun;SUN Chaofan;ZHAO Ning;SHEN Yueliang;China Southern Power Grid Technology Co.,Ltd.;

    Under the background that coal-fired power plants fully participated in deep peak shaving, the rate and range of changed load had increased, the delay problem of urea hydrolysis technology was further serious, posing a threat to the safety of equipment and environment. Therefore, solutions are proposed from two different perspectives, equipment and control optimization. In terms of equipment optimization, metal oxides especially as η-Al_2O_3 and α-MnO_2 had a significant catalytic effect on the urea hydrolysis reaction, which can effectively speed up the reaction rate, reduce the system delay. What's more, the η-Al_2O_3/α-MnO_2 catalytic hydrolysis system could be completed by the common urea hydrolysis system and little modification, which was very suitable for spreading and applicating. As for control optimization, a feedforward adjustment model of denitrification system based on stepwise regression equations and a feedforward adjustment model of urea hydrolysis system based on reaction kinetic equations were established to realize advance control of ammonia injection amount and urea hydrolysis conditions, and solving the delay problem of denitrification ammonia injection and urea hydrolysis.

    2024 S2 v.30 [Abstract][OnlineView][Download 263K]

  • Current situation and prevention countermeasures of pneumoconiosis in Chinese coal enterprises

    WANG Yanbing;FENG Lezhen;Distribution Center of National Energy Group Shendong Coal Group;Mathematics Group of Ordos No.3 Middle School;

    Coal mines are the hardest hit areas of dust hazards, and 80% of pneumoconiosis patients in China come from coal mines. In the process of coal mining, cutting, drilling, blasting, transportation and other technological links are needed in the comprehensive mechanized coal mining and excavation. These processes will bring a lot of rock dust and coal dust. If human lungs inhale a large amount of dust for a long time, they may suffer from pneumoconiosis. The key to prevent pneumoconiosis is to reduce the dust concentration in the workplace. At present, the comprehensive dust prevention measures mainly rely on wind and water as the medium for dust removal. Discusses the problems existing in the management of pneumoconiosisfrom the perspectives of government, enterprise managers, employees and society, and puts forward solutions.

    2024 S2 v.30 [Abstract][OnlineView][Download 140K]

  • Distribution of heavy metals in the collaborative treatment of refuse derived fuel

    ZHANG Wei;WANG Mingwei;National Energy Group Yongzhou Power Generation Co.,Ltd;Energy Power and Mechanical Engineering Department,North China Electric Power University;

    For rational disposal of refuse derived fuel(RDF),RDF was co-treated in a gasifier coupled pulverized coal furnace system, and the migration characteristics and environmental risks of heavy metals were also studied. The results showed that a large proportion of heavy metals in blank condition were distributed in fly ash, accounting for 61.5%-87.8%. 11.7%-35.2% of heavy metals were distributed in slag. About 9% of Cd and As were distributed in desulfurized gypsum, and the proportion of other heavy metals in desulfurized gypsum was less than 4%. 5.3% of Cd was distributed in flue gas, and the distribution proportion of other heavy metals was less than 0.2%. The distribution of heavy metals in coupling condition was quite different from that in blank condition. The proportion of Cd, Pb, As, Ni and Ba in gasifier products(slag and cyclone dust) was between 0.8%-28.1%,and the proportion of Cr, Cu and Zn in gasifier products was between 58.5%-71.9%. The leaching concentration of solid products under the two conditions was lower than standard limit, but the leaching concentration of Cr, Ni, Cu, Zn and Ba in the gasification slag and cyclone dust under the coupling condition was higher. The leaching concentration of Cr in the gasification slag had reached 80.3% of the standard limit. The gasification slag and cyclone dust generated at low temperature have poor effect on the fixation of heavy metals and have higher environmental risks.

    2024 S2 v.30 [Abstract][OnlineView][Download 874K]

  • Technology for secondary air equalization based on the turning performance simulation of air damper

    CHENG Tongrui;LI Jinjing;CHENG Liang;ZHAO Yaohua;YANG Dong;CHEN Xiaofeng;TONG Boheng;LI Yuanyuan;JIANG Long;North China Electric Power Research Institute Co.Ltd.;China Energy Engineering Co.Ltd.;State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University;

    The secondary air equalization is the prominent factor of good combustion organization in boiler. The former technology of secondary air equalization encounters many problems, such as large measurement error, high test energy consumption, bad working environment and rigid test time, which cause obvious departure from expectation. The turning performance of secondary air damper was studied by establishing the fluid simulation model of the secondary air system, and represented with the quantitative relationship between the resistance coefficient and the damper angle. The result shows that the greater the damper angle is, the greater the damper angle allowable error is, within the certain allowable error of air flow. Furthermore, a novel checking and assessing technology for turning performance of the secondary air damper is developed, independent of air flow. The two characteristics were created, checking damper angle instead of the air flow rate, and assessing the damper angle error instead of the air flow rate error. The proof test was conducted on a 600 MW subcritical boiler. This technology checks and assesses turning performance of the secondary air damper safely, accurately, efficiently and economically. Incorporating with the effective defect elimination, the secondary air equalization can fit the expectation well.

    2024 S2 v.30 [Abstract][OnlineView][Download 448K]

  • Numerical investigation of electrostatic effect in fluidized bed based on CFD-DEM

    LI Bin;FAN Linda;WANG Tai;LIU Pengyu;School of Energy Power and Mechanical Engineering,North China Electric Power University;China Energy Engineering Group Guang Dong Electric Power Design Institute Co.,Ltd.;

    Gas-solid fluidized bed is widely used in the coal chemical industry, coal combustion, and coal separation due to its high heat and mass transfer efficiency. However, in the process of fluidization, the frequent contact and collision between particles and particles or wall surfaces lead to the generation of electric charges on the surface of particles, resulting in the adhesion of particles to the reactor wall, particle agglomeration and electrostatic discharge, which affects the movement state, porosity and mixing degree of particles, and even causing production accidents. To explore the influence of the electrostatic effect on the gas-solid two-phase flow characteristics in the fluidized beds, based on the developed double-grid system CFD-DEM simulation program, coupled with the electrostatic force model, the gas-solid two-phase fluidization process in a single-hole jet fluidized bed was numerically simulated. The gas-solid two-phase flow characteristics in the fluidized bed before and after considering the electrostatic force were studied from the perspectives of the whole bed and the tracer particles in the typical area. The results show that after considering the electrostatic force, the particle distribution becomes more dispersed, the bed voidage increases, the bed expansion height increases, and the motion trajectories of particles at the same initial position changes. The motion and velocity distribution of particles in the fluidized bed is approximately axisymmetric, and the vertical and horizontal velocities of particles in the stagnation zone are always close to zero. With the increase of the electric charge carried by particles, the particle velocity vector in the fountain area is gradually sparse, the particle velocity vector in the spray area is gradually dense, and the Lacey mixing index shows a certain degree of slowdown. The above research results and methods can provide a reference for further research and practical engineering application.

    2024 S2 v.30 [Abstract][OnlineView][Download 655K]

  • Molecular simulation of CO2 adsorption by molecular sieves in flue gas of coal-fired power plants

    YANG Xu;WANG Weiyun;HUANG Hangyu;ZHOU Can;School of Energy and Environment, Shenyang Aerospace University;

    CO_2 separation is of great significance to environmental protection and energy conversion as CO_2 is the main gas of greenhouse effect. The adsorption performance of the material for CO_2 is the key to determine the adsorption efficiency. Zeolite molecular sieve, a renewable inorganic material with high specific surface area, high porosity and strong thermal stability, has attracted much attention in the field of CO_2 adsorption in recent years. Previous researchers have extensively studied the adsorption capacity of molecular sieve adsorbents for CO_2, N_2, CH_4 and other atmospheres through simulations, but there are few studies on the adsorption simulation of the complex flue gas environment existing in the flue gas of actual coal-fired power plants. The gas as N_2, H_2O, O_2, SO_2,which existed in the flue gas of coal-fired power plants will affect the adsorption of CO_2 by molecular sieves. Therefore, select the main components in the flue gas to construct two-component and multi-component adsorption comparisons. Respectively construct four groups of two-component atmosphere simulations including CO_2-N_2, CO_2-H_2O, CO_2-O_2, CO_2-SO_2 and multi-component atmosphere simulations including N_2, H_2O, SO_2, CO_2 and O_2 were constructed. Silica MFI type zeolite molecular sieve model was constructed by Material Studio. Molecular optimization was by Dmol~3 which is a function module in Materials Studio. The GCMC method was used to calculate the adsorption amount of zeolite on simulated flue gas, and explore each gas group under the actual temperature and pressure range of flue gas. Through the analyze of the change of adsorption performance and CO_2 adsorption selectivity of different components, the effect of temperature and pressure on the adsorption and separation of CO_2 in binary mixed components was discovered, and the relationship between each component and CO_2 during the adsorption of binary system was analyzed. According to the adsorption competition law, the adsorption performance of each gas component and the change of CO_2 adsorption selectivity were explored, and the optimal temperature and pressure for separating CO_2 in simulated flue gas were obtained. The results show that when the binary components are adsorbed, CO_2 is in a dominant position in the competition with N_2, H_2O and O_(2 )components, and the reduction of temperature is conducive to the separation of CO_2, in the competition with SO_2, it is in a weak position. The increase in temperature and pressure favors the separation of CO_2. During the adsorption of multiple components, the adsorption capacity of the gas is affected by factors such as number density, temperature, pressure, and the interaction strength between the gas molecules and the zeolite framework. Under the same conditions, the order of adsorption amount of MFI zeolite to each gas is τ_(CO2)>τ_(SO2)>τ_(N2)>τ_(H2O)>τ_(O2 )when the temperature is lower than 413.15 K; τ_(CO2)>τ_(N2)>τ_(SO2)>τ_(H2O)>τ_(O2) when the temperature is higher than 413.15 K. Under the conditions of temperature 413.15 K and pressure 1 500 kPa, the separation ratio of CO_2 with other gases in the simulated flue gas reached the highest value of 1.314, and the adsorption amount of CO_2 was 1.239 mmol/g.

    2024 S2 v.30 [Abstract][OnlineView][Download 1979K]

  • Numerical simulation of salt crust effect on droplet evaporation of desulfurization wastewater from coal-fired plant

    LING Haibo;QI Nana;ZHANG Kai;Beijing Key Laboratory of Monitoring and Control of Pollutants in Thermoelectric Processes,North China Electric Power University;

    Aiming at the flue spray evaporation process of desulfurization wastewater, a model of flue gas and liquid droplet flow and heat and mass transfer was established by Euler-Lagrange method, and the model was used to simulate the flue gas spray evaporation process of a 330 MW unit of a power plant. By considering the differences of thermal conductivity caused by the salt crust formed on the surface of desulfurization wastewater during evaporation, the effects of flue gas temperature and gas velocity on the evaporation characteristics of pure water droplets and 60 μm droplets with 5 μm thick salt crust were analyzed. The results show that the difference of heat and mass transfer properties leads to the difference of evaporation characteristics between pure water and salt-crust droplets. The total evaporation time of salt-crust wastewater droplets is longer than that of pure water droplets within the flue gas temperature range, and the difference decreases with the increase of initial flue gas temperature. As the gas velocity increases, the total evaporation time of the two droplet groups becomes shorter, and this influencing factor has a greater effect on the salt-crust droplets.

    2024 S2 v.30 [Abstract][OnlineView][Download 4398K]

  • Development and application of rapid leakage detection technology for low-temperature economizer

    LEI Yu;WANG Bo;ZHANG Zhixiang;XUE Ning;JI Haimin;Xi'an Thermal Power Research Institute Co.,Ltd.;

    The power plant is facing great pressure on the stable operation of low-temperature economizer, especially its leakage problem needs to be solved urgently. In order to detect the leakage of low-temperature economizer instantly, this paper proposes a rapid leakage detection technology based on the flue gas temperature monitoring after low-temperature economizer. Through the numerical simulation of the flue gas temperature change after the leakage of low-temperature economizer by COMSOL, it is found that the flue gas temperature after the leakage point can be reduced by 2 ℃ compared with the normal flue gas temperature. Thus, by arranging multiple temperature measuring points on the whole flue section behind the low-temperature economizer in a matrix manner, monitoring the temperature at different points or the temperature change rate and amplitude at the same point, we can quickly determine whether the low-temperature economizer has leakage, and then cooperate with the water side pressure test to achieve rapid leakage detection. In addition, this paper also gives specific suggestions from the design, operation and maintenance of low-temperature economizer, which has significant engineering significance for improving the operation stability of low-temperature economizer in power plants.

    2024 S2 v.30 [Abstract][OnlineView][Download 987K]

  • Retrofit of near-wall air system of a 600 MW opposed firing boiler

    HUO Hongbin;SU Fei;MENG Pei;ZHANG Bin;BI Yanjun;LUO Hongfei;SUN Jindong;ZHAO Peng;WANG Xiaohua;WAN Qianmin;CHEN Tao;LIU Haitao;SUN Lushi;CHN Energy Bengbu Power Generation Co.,Ltd.;Suzhou TPRI Energy and Environmental Technology Co.,Ltd.;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;Guangxi Huayu Energy Technology Co.,Ltd.;

    Aimed at high-temperature corrosion in a 600 MW opposed firing boiler, a sidewall near-wall air protection scheme was proposed. The numerical simulation of the boiler was conducted to analyze the velocity field, temperature field, and component distribution before and after the retrofit under full load condition. After the scheme was implemented in the boiler, the test of reductive atmosphere near the side water wall and thermal efficiency of the boiler was carried out. The implementation of the scheme results in a reduction in the high-speed zone and an increase in the residence time of coal particle, promoting more efficient coal combustion and reducing the concentration of reductive gas near the side wall. The temperature above the over-fire air near the side wall decreases, minimizing the temperature deviation of flue gas. The average volume fraction of O_2 near wall increases 2.00% from 0.19%. The average volume fraction of CO decreases from 920×10~(-4) to 150×10~(-4),and the average volume fraction of H_2S decreases from 200×10~(-6) to 150×10~(-6). The reductive atmosphere is effectively destroyed which can effectively alleviate high temperature corrosion. Furthermore, the retrofit led to improvements in thermal efficiency, with increase of 0.69%,0.71%,and 0.77% observed at load levels of 300,450,and 600 MW,respectively. This research aims to provide both theoretical and engineering references for future studies.

    2024 S2 v.30 [Abstract][OnlineView][Download 552K]

  • Water-cooled wall expansion characteristics based on online monitoring data analysis

    ZHANG Yan;GUO Zhengwang;HUO Yingao;XIAO Haiping;YANG Zhiping;Guoneng Jinjie Energy Co.,Ltd.;Energy Power and Mechanical Engineering Department,North China Electric Power University;

    The expansion state of the boiler water-cooled wall affects the stable and safe operation of thermal power units. The expansion characteristics of the boiler of a supercritical unit based on online monitoring data was evaluated. Based on the least-squares method, the expansion displacement data of the boiler measurement points during the normal operation stage were fitted, and the expansion of the measurement points during the normal operation stage was shown by expansion displacement fluctuation rate. The results show that the boiler expansion during start-up and shutdown phases varies sharply with time, while the expansion monitoring value during normal operation fluctuates around the design value of thermal expansion. The average fitted value of Z-direction displacement at the cold ash hopper is 24.73 mm smaller than the thermal design value, which may be due to the boiler water-cooled wall absorbing part of the expansion through yielding or deformation. There are differences in the horizontal expansion of different measurement points at the same elevation. The fluctuation rate δ of the Y-axis displacement at measurement point No. 5 is basically distributed within ±5%,while only 33.05% of the monitored expansion values at measurement point No. 6 have a fluctuation rate within ±5%,which may be due to the uneven distribution of the combustion power field. Therefore, the water-cooled wall expansion monitoring analysis can effectively reflect the boiler equipment status.

    2024 S2 v.30 [Abstract][OnlineView][Download 588K]

  • Purification of NO and PM indiesel engine exhaust by woody La0.9K0.1Co0.95Ni0.05O3

    WANG Yinghui;GUO Xiurong;LU Zhensheng;BAI Xilong;CHENG Miao;School of Electrical Engineering,Sui Hua University;College of Mechanical and Electrical Engineering,Northeast Forestry University;

    In order to enhance the catalytic activity of LaCoO_3 perovskite-type catalysts for NO and PM emitted from diesel engine. La_(0.9)K_(0.1)Co_(0.95)Ni_(0.05)O_3 perovskite-type catalyst samples were prepared by sol-gel method and biological template method taking wood powder as template, respectively. The physical and chemical properties of the catalyst samples were characterized by XRD,FT-IR,SEM and N_2 adsorption/desorption testing technology. The purification performance of catalyst samples for NO and PM were conducted by simulation test. The results show that the catalyst samples prepared by the both methods exhibit obvious perovskite structure and high purity. The specific surface area of catalyst sample prepared by biological template method is 7.22 m~2/g, the specific surface area of catalyst sample prepared by by sol-gel method is 6.26 m~2/g. Woody La_(0.9)K_(0.1)Co_(0.95)Ni_(0.05)O_3 perovskite-type catalyst sample prepared by biological template method can successfully replicate the structural characteristics of wood powder from macroscopic to tracheid, forming a porous structure. The simulation test results show that woody La_(0.9)K_(0.1)Co_(0.95)Ni_(0.05)O_3 perovskite-type catalyst shows better catalytic activity than powdery La_(0.9)K_(0.1)Co_(0.95)Ni_(0.05)O_3 perovskite-type catalyst samples. When the simulated exhaust temperature is 400 ℃,the highest purification efficiency catalysts for NO and PM can reach 78% and 90%,which can be attributed to the fact that porous catalyst increased the contact area and number of contact points between particles and catalyst.

    2024 S2 v.30 [Abstract][OnlineView][Download 388K]

  • Physical characteristics and diffusion law of dust in tape transportation corridor of coal processing plant

    QIU Siran;LI Yun;HE Qingquan;ZENG Fabin;JIANG Zhongan;National Energy Group Xinjiang Energy Co.,Ltd.;School of Civil and Resource Engineering,University of Science and Technology-Beijing;

    In order to solve the problem of serious dust pollution in the tape transportation gallery of Zhundong coal preparation plant, the distribution of dust concentration in the tape transportation gallery under different conditions was studied by on-site investigation and determination of physical properties of dust, combined with numerical simulation in the tape transportation gallery of coal preparation plant 101 in an open-pit mine in Zhundong, Xinjiang, as a research object. The results show that the average contact angle of dust in the belt conveyor gallery is 87.9°,the hydrophilicity is poor. The dust mass concentration in the belt transportation gallery decreases and then increases with the increase of inlet wind speed, and increases with the increase of tape running speed, and the wetting of the wall surface of the belt gallery can effectively reduce the dust concentration. The optimal exhaust wind speed of the belt gallery is 3 m/s, and the optimal tape running speed is 3 m/s.

    2024 S2 v.30 [Abstract][OnlineView][Download 1548K]

  • Prediction of coal storage in thermal power plants based on CNN-LSTM combination algorithm

    HAN Yi;FU Xuchen;CAI Bin;WANG Yankai;YU Yingli;Inner Mongolia Electric Power Research Institute Branch,Inner Monglia Electric Power(Group)Co.,Ltd.;Key Laboratory of Energy Thermal Conversion and Control,Ministry of Education,Southeast University;

    Coal is the ballast and stabilizer in the construction of modern energy systems. Considering the demand for early warning of coal inventory for energy and electricity safety, a short-term coal inventory prediction method based on deep integration of convolutional neural networks and long short-term memory neural networks was proposed, taking into account the advantages of CNN and LSTM network models, achieve the prediction of coal inventory in thermal power enterprises.The CNN-LSTM electric coal stock prediction model fully utilizes the advantages of CNN algorithm in deep extraction of potential patterns from multi-source data, and excavates and integrates high-quality data feature information as input values for the LSTM model. By leveraging the LSTM algorithm′s ability to model long-term and short-term temporal dependencies, high-precision and complex nonlinear temporal mapping correlations was constructed, effectively improving the accuracy of predicting the stock of electric coal. After testing data from thermal power enterprises, it has been shown that the CNN-LSTM model adopts 2-layer CNN convolution and 2×2 convolutional kernels, 16 and 32 convolutional kernels, 2 pooling operations, 1 flattening operation, and a 3-layer LSTM network design. The model is trained through two stages of forward and backward propagation to achieve fully connected layer output prediction results. The R_(MSE) and M_(APE) prediction errors are about 0.903 and 2.74%,respectively. Compared with the traditional prediction methods of Elman and LSTM networks, the predicted curve is highly consistent with the actual trend, and the prediction accuracy and stability are the best, with an accuracy improvement of 20%-47%.

    2024 S2 v.30 [Abstract][OnlineView][Download 681K]

  • Performance analysis of an integrated drying pyrolysis and treatment system based on the efficient utilisation of municipal sludge

    WANG Chizhong;FAN Junyi;CHEN Heng;XU Gang;ZHANG Guoqiang;College of Energy Power and Mechanical Engineering,North China Electric Power University;

    An integrated system of sludge drying pyrolysis and treatment was proposed to accelerate the elimination of urban sludge and realize the resourceful use of sludge. Pyrolysis oil and pyrolysis coke was sold and processed. Pyrolysis gas was used for combustion to generate electricity, and the high-temperature gas generated in the pyrolysis and combustion process was used to heat the drying process and equipped with a waste heat utilization system. On this basis, the system's energy and economic analysis were carried out. The calculation results show that the energy efficiency of the integrated system of sludge drying pyrolysis and treatment is 56.94%,the payback period is 13.32 years, and the net present value is 17.493 1 million yuan. The sensitivity analysis show that the NPV of the system is zero when the low-level heat generation of the sludge dry basis is 9.52 MJ/kg. The system remains profitable when the selling price of the pyrolysis oil is reduced by no more than 25.20%,or the sludge treatment subsidy is reduced by 38.46%.

    2024 S2 v.30 [Abstract][OnlineView][Download 248K]

  • Monitoring of slagging and soot-blowing optimization in waterwall based on heat loss analysis

    LIU Jun;HUANG Yaji;XU Wentao;YUE Junfeng;WANG Sheng;GAO Jiawei;QI Shuaijie;ZHAO Jiaqi;ZHANG Yuyao;Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University;Jiangsu Frontier Electric Power Technology Co.,Ltd.;State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control;

    Currently, most coal-fired power plants adopt a timed and quantified ash blowing scheme, which may easily lead to insufficient or excessive ash blowing on the heating surface. Taking a 650 MW ultra-supercritical DC boiler waterwall as the research object, a slag monitoring model for the waterwallwas established based on heat loss and GA-BP neural network. Subsequently, an soot blowing optimization model for the waterwall was established with the maximum net profit of soot blowing as the optimization objective. Considering the different removal effects of ash blowing devices arranged at different heights in the furnace, a segmented fitting of ash blowing increment superimposed curve was performed. Finally, two existing ash blowing schemes in the power plant were optimized and analyzed. The results indicate that the soot blowing efficiency is higher when the soot blowers on layers D-F are started, but after optimizing the soot blowing strategy for the soot blowers on layers A-F,a greater net soot blowing benefit can be obtained. When the soot blowing time for the waterwall of the target boiler is set to 3 556 seconds, and the interval between the two soot blowings is set to 10 600 seconds, starting the soot blowers sequentially from layer A to layer F,with each soot blower running for the same amount of time, the maximum net profit of soot blowing obtained is 6 449.41 kW. Compared to the optimized results of starting the soot blowers on layers D-F,the net profit of soot blowing is increased by 17%.

    2024 S2 v.30 [Abstract][OnlineView][Download 661K]

  • Comprehensive evaluation method of coal separation process based on combination weighting and cloud model with cloud entropy optimization

    ZHANG Jun;WEI Wenpeng;ZHANG Shuo;JIANG Kunkun;WANG Jie;LI Shaoning;DONG Liang;DAI Wei;Guodian Jiantou Inner Mongolia Energy Investment Co.,Ltd;Dadi Engineering Development Co.,Ltd.;School of Chemical Engineering & Technology,China University of Mining & Technology;

    The effective evaluation of coal separation process is an important basis to reflect the process performance, and it is also an important measure to promote the development of coal preparation industry towards high efficiency and cleanliness. This paper proposed a comprehensive evaluation method based on cloud model and combination weighting. Firstly, based on game theory and expert scoring matrix, the subjective weight and objective weight were integrated to obtain the final expert score. Secondly, the cloud model based on cloud entropy optimization converted the qualitative concepts of each evaluation level into quantitative values. Finally, the evaluation results were obtained according to the certainty of the expert score on the cloud model of each evaluation level. The production and operation data of a certain month were selected from a coal preparation plant for validation, and the proposed method can accurately reflect the actual situation of the coal preparation process in that month. By using the classical fuzzy comprehensive evaluation method for comparison and validation, its Q value is 0.999 1,and the evaluation level is consistent with the above results, proving the strong feasibility of the cloud model-combined weighting coal selection process comprehensive evaluation method based on cloud entropy optimization.

    2024 S2 v.30 [Abstract][OnlineView][Download 293K]

  • Life cycle carbon emission, energy consumption and economic cost analysis of heavy trucks with different technical routes

    LING Bo;ZHU Guangyan;WANG Wen;WANG Changfang;WANG Minghua;TIAN Yajun;China Energy Technology and Economics Research Institute;Extended Energy Big Data and Strategy Research Centre,Qingdao Institute of Bioenergy and Bioprocess Technology,Chinese Academy of Sciences;Shandong Energy Institute;Qingdao New Energy Shandong Laboratory;School of Chemical Engineering,University of Chinese Academy of Sciences;

    In recent years, controlling and reducing CO_2 emissions has become a global consensus. In the transportation industry, heavy trucks bear the important function of cargo transportation, but their CO_2 emission accounts for 40% of the whole industry, so the development of new energy heavy trucks is urgent. At present, electric heavy trucks are developing rapidly, and hydrogen(ammonia) energy heavy trucks have also attracted extensive attention from experts and scholars, but there is still a lack of systematic research on their energy consumption, carbon emission and economy. Nine technology routes(electric, diesel, hydrogen, and ammonia) from technical, environmental, and economic perspectives were evaluated, the entropy weight method coupled with carbon emission, energy consumption, and economic cost indexes to assess and compare the comprehensive competitiveness of different technology routes were employed. The results show that the relevant technology routes currently based on traditional fossil energy sources generally have higher energy consumption and carbon emissions but lower costs, while the technology routes related to renewable energy sources have lower carbon emissions and energy consumption but relatively higher economic costs. With the reduction of fuel costs and the rise of carbon prices, by 2060,electric heavy trucks will have the highest competitiveness under ambient conditions, the comprehensive competitiveness of diesel heavy trucks will gradually decrease, and the comprehensive competitiveness of hydrogen(ammonia) fuel cell heavy trucks based on green hydrogen(ammonia) will gradually increase. Under low-temperature conditions, starting from 2030,hydrogen(ammonia) fuel cell heavy trucks(photovoltaic, wind power hydrogen and ammonia production) will have the highest comprehensive Competitiveness. In the future, a new type of heavy-duty truck transportation system will gradually be formed with electric heavy-duty trucks as the main part and hydrogen(ammonia) fuel cell heavy-duty trucks as the supplementary part.

    2024 S2 v.30 [Abstract][OnlineView][Download 519K]

  • Numerical simulation on heat and mass transfer process of spray-drying flue gas desulfurization

    LIU Baoxia;MA Zhuoqun;WANG Zongming;YU Zhenxing;Repair & Overhaul Center,Pipe China Compressor Set Maintenance;China University of Petroleum(East China);Sinopec Qingdao Refining & Chemical Co.,Ltd.;

    Spray drying flue gas desulfurization technology has the advantages of simple process and low initial investment, which is widely used in small and medium-sized enterprises for flue gas treatment. But it has the problems of low desulfurization efficiency and high inlet flue gas temperature, which increases the operating cost and reduces the overall efficiency of the boiler. Based on the double membrane theory and using CPFD numerical simulation method, the water evaporation model and the desulfurization reaction model were established and the heat and mass transfer process of spray-drying flue gas desulfurization was studied for a small desulfurization tower. The results show that the larger the calcium-sulfur ratio, the higher the desulfurization efficiency, and when the calcium-sulfur ratio is greater than 2.0, the improvement of desulfurization efficiency is not obvious. With the increase of the droplet diameter the desulfurization efficiency increases firstly and then decreases, and the optimal range of the droplet diameter is 40-60 μm. When the inlet flue gas temperature is within the range of 403-438 K, the desulfurization efficiency can be more than 76.6%, which makes it possible to reduce the flue gas temperature of the boiler. The constant speed drying stage occurs in the upper 1/3 of the desulfurization tower and the time of duration is short, which is not conducive to the improvement of the desulfurization efficiency. Increasing the slurry water content can extend the time of the constant speed drying stage, and the desulfurization efficiency can be increased to 90.26%. The research results provide theoretical reference for improving the desulfurization efficiency and reducing the energy consumption of spray drying desulfurization.

    2024 S2 v.30 [Abstract][OnlineView][Download 1465K]

  • Key technology of green short process treatment under high turbidity and high viscosity mine water

    ZHANG Jianguo;WANG Zhifeng;HE Xuwen;ZHAO Lei;ZHANG Xuefei;WANG Shaozhou;MA Wencheng;State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization;China Pingmei Shenma Holding Group Co.,Ltd.;Century Huayang Environmental Engineering Co.,Ltd.;School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing;

    The high turbidity and high viscosity mine water were treated by PolyCera membrane direct filtration technology, the treatment effect of poly-porcelain film was verified, the process operation parameters were optimized, and the relevant engineering design parameters were found out. The experimental results show that the pollution resistant membrane material and the unique flow channel design the PolyCera membrane can treat the high turbidity and high viscosity mine water without the addition of drug direct filtration, and can withstand the high concentration of suspended matter, without the addition of drug direct filtration can avoid the influence of drug addition on the advanced treatment unit. The membrane pollution is mainly caused by the clogging of the cake layer and accompanied by the middle clogging. The membrane pollution can be effectively removed by chemical cleaning, and the recovery rate of the membrane can reach more than 95% after chemical cleaning. The pilot test results show that the viscosity of the suspended matter is relatively high after it is trapped and accumulated by the filter, and it will adhere to the surface of the filter core. The self-cleaning filter with rotating brush should be preferred for pretreatment. The optimal circulation flow rate of the PolyCera membrane ultrafiltration system is 24 m~3/h, the optimal operating pressure is 0.2 MPa, and the influent turbidity is between 542-905 NTU. The turbidity of the water produced is always less than 0.4 NTU, and the system is stable and can be unattended. The underground engineering practice shows that the 200 m~3/h scale of poly ceramic membrane direct filtration technology is applied to the underground, without complex pretreatment process, small footprint, stable effluent quality, high degree of automation, low operating costs, high water production efficiency, power consumption is only 0.37 yuan/ton of water, but also can save the well cost of 5.068 800 yuan/year. It can realize the new requirements of green short process, energy saving, high efficiency and intelligent unattended mine water treatment, and has broad application prospects.

    2024 S2 v.30 [Abstract][OnlineView][Download 1285K]

  • Numerical simulation of flow field for dewatering of refined coal chute at the end of the airflow-enhanced finish

    BAI Xiaojun;ZENG Hongjiu;LIU Qinju;WANG Dapeng;CHN Energy Shendong Coal Preparation Center;CHN Energy Shendong Technology Research Institute;China University of Ming and Technology;

    In order to improve the recycling of waste energy from industrial production in the coal preparation plant, the waste heat generated during the operation of the pressurised filter press fan was used for further dewatering in the final fine coal chute, and a rectangular air inlet(wind knife) was set in the discharge chute of the final fine coal centrifuge, which introduced the waste heat into the chute to dry the fine coal. The model was established by SolidWorks and imported into ICEM CFD for meshing, and then imported into Fluent for boundary condition setting and numerical simulation calculation. The influence of the wind knife position, the number of wind knives, the angle of wind knives and the hot air velocity on the internal flow field of the chute was systematically investigated. The results show that under the conditions of double wind knives, air velocity of 45 m/s, angle of 0° and height of 600 mm, the distribution of airflow in the chute can be obviously optimized, and the area with air velocity of 0 m/s does not appear in the axial direction at a distance of 200 mm to the right of Y-axis of the central plane(near the side of the single wind knife). The airflow field is more comprehensive and uniform, which provides a basic support for the utilisation of waste energy from the coal preparation plant.

    2024 S2 v.30 [Abstract][OnlineView][Download 518K]

  • Safetyrisk identification and control mechanism for ammonia mixed combustion system in coal-fired power plant boilers

    ZHAO Xiuliang;CUI Liming;LIU Ping;YANG Tieqiang;CAO Jianjun;ZHANG Wenzhen;NIU Tao;CHU Wei;Guangdong Branch,China Shenhua Energy Co.,Ltd.;China Shenhua Energy Co.,Ltd.;Yantai Longyuan Power Technology Co.,Ltd.;Guoneng Yuedian Taishan Power Generation Co.,Ltd.;

    The clean and efficient combustion technology of ammonia mixed combustion in coal-fired power plant boilers, when choosing green ammonia to replace some coal, can synergistically solve the dual problems of new energy consumption and storage and retaining existing coal-fired power. It is a feasible route that can coordinate multiple goals and achieve steady and orderly promotion of energy green and low-carbon transformation and development. But in view of the combustion characteristics and hazardous chemical properties of zero carbon ammonia fuel, how to ensure the safety and reliability of the ammonia mixed combustion system and equipment in large capacity coal-fired power plant boilers is a core issue that is related to its future promotion and application. Based on the actual engineering verification of ammonia mixed combustion in large capacity coal-fired boilers, the safety risk points of boiler mixed with ammonia combustion were summarized and analyzed. All elements from the aspects of boiler ammonia mixing state switching regulation, combustion stability, pollutant exceeding standards, compatibility and matching with boiler original equipment, ammonia corrosion and leakage, etc were classified and identified. Based on theoretical research and experimental results, the probability of risk occurrence was evaluated. A complete safety risk prevention and control mechanism for the ammonia mixed combustion system of coal-fired power plant boilers were proposed. It is pointed out that the risks of ammonia blending combustion in large capacity coal-fired power plant boilers can be effectively avoided by developing key ammonia mixing equipment for low nitrogen combustion of adaptable ammonia coal blending combustion, designing a reasonable ammonia mixing combustion system, and constructing early warning controls such as logic protection. This set of safety risk prevention and control mechanisms for the ammonia mixed combustion system provides a safety guarantee for the future promotion of clean and efficient ammonia blending combustion in coal-fired power plant boilers.

    2024 S2 v.30 [Abstract][OnlineView][Download 523K]

  • Application of wide temperature platedenitration catalysts installed in the spare layer in 1 000 MW units

    LIU Changsheng;JIA Haiwei;WU Yuanyuan;CHEN Jia;Li Yue;REN Cuitao;LIU Dingjia;Hubei Energy Group Ezhou PowerGeneration Co.,Ltd.;Zhejiang Kezhuo Environmental Protection Technology Co.,Ltd.;Hubei Energy Group Jiangling Power Generation Co.,Ltd.;Beijing National Power Group Co.,Ltd.;

    A coal-fired power plant installed wide temperature plate selective catalytic reduction(SCR) denitration catalysts on the spare layer of the existing honeycomb SCR catalyst system to achieve the deep peak load regulation and ultra-low NO_x emission of 1 000 MW units. After the renovation, the units can achieve an overall denitrification efficiency of 94.9% and ammonia escape of 1.8 μL/L when operating at 30% load. After 15 months of continuous operation, the wide temperature plate catalyst was tested. The results show that the performance of the catalyst is stable, the denitrification activity decreases slightly and no obvious poisoning occurred. This application proves that the way of installing a wide temperature plate catalyst on the backup layer can meet the needs of deep peak load regulation and ultra-low NO_x emission of coal-fired units, and this modification scheme has obvious advantages in engineering investment and operating cost, providing a reference for the subsequent modification of other units of the same type.

    2024 S2 v.30 [Abstract][OnlineView][Download 804K]

  • Research on CO2 capture technology for organic fuel combustion gas

    GAO Ningbo;WANG Mingchen;YANG Tianhua;GUO Aijun;QUAN Cui;LI Rundong;College of Energy and Environment,Shenyang Aerospace University;School of Energy and Power Engineering,Xi'an Jiaotong University;Technology Research Institute,Shendong Coal Group of China Energy Group;Shaanxi Weihuanneng Tech.Co.;

    As the main component of greenhouse gases(GHGs),carbon dioxide gradually intensifies the greenhouse effect. Since industrialization, the growth of global economy and the increase of population have made the use of fossil fuels surge, which leads to the surge of CO_2 emissions, resulting in global warming, extreme weather and other climate impacts. However, organic fuels are expected to remain the dominant energy provider for a long time to come. Therefore, capturing carbon dioxide from organic fuel flue gas at the source of carbon dioxide emissions can fundamentally mitigate the greenhouse effect. CO_2 capture is the first and most critical step in CO_2 capture and storage(CCS). This paper introduces the existing CO_2 capture methods, including pre-combustion CO_2 capture, post-combustion CO_2 capture and oxy-combustion. The post-combustion CO_2 capture is described, including absorption, adsorption and membrane separation. In addition, the operating costs of each technology were also analyzed.

    2024 S2 v.30 [Abstract][OnlineView][Download 1449K]

  • Collaborative control technology for flow field and resistance in the inlet and outlet flue of the IDF of a 1 000 MW coal-fired boiler

    LIU Hongfang;PENG Xiaomin;SHEN Li;WANG Zhun;LIU Kairui;Zhejiang Zheneng Electric Power Co.,Ltd.;Xi′an Thermal Power Research Institute Co.,Ltd.;Zhejiang Zheneng Taizhou Second Power Generation Co.,Ltd.;

    The layout of the inlet and outlet flues of a 1 000 MW coal-fired boiler′s induced draft fan(IDF) is unreasonable, and the flow field environment where the IDF is located is poor, which has caused safety issues such as forced draft fan scrambling and IDF vibration under high load. The resistance of the tail flue is increasing year by year, limiting the output of the IDF under high load, causing the IDF to be at the edge of stall under high load conditions, further deteriorating the operating conditions of the IDF,and seriously affecting the safety and economy of the IDF operation. Firstly, the CFD simulation method was used to analyze the problems existing in the current flow field of the inlet and outlet flues, diagnose and analyze the resistance concentration area and resistance reduction space, and through the numerical simulation test, the distribution uniformity and stability of the flow field of flues were significantly improved, and the flue resistance was effectively reduced, And it has been applied in practice. The experimental results after the transformation show that the relative standard deviations of flue velocity are 12.1% and 12.0%,respectively, and the relative standard deviation of flue velocity at the outlet is 12.7%. The flue resistance has decreased by a total of 464 Pa, and the uniformity of the flue flow field has been significantly improved. The flue resistance has been significantly reduced, and the operating conditions of the IDF have been significantly improved, enhancing the safety and economy of boiler. Within nearly a year after the implementation of the renovation, the IDF has not experienced any safety issues such as fan scrambling, vibration, or stall under high load conditions. The IDF can maintain safe and stable operation for a long time. The research case has typical representativeness and has promotional significance.

    2024 S2 v.30 [Abstract][OnlineView][Download 3774K]

  • Application of model predictive control technologyin SNCR denitrification system

    PAN Qin;GAO Chang;SUI Haitao;Guoneng Changyuan Wuhan Qingshan Thermal Power Co.,Ltd.;Yantai Longyuan Electric Power Technology Co.,Ltd.;

    Selective non-catalytic reduction(SNCR) process is commonly used in the denitrification system of circulating fluidized bed(CFB) boilers. The spray gun is arranged at the horizontal flue between the furnace outlet and the separator inlet. The control system can only rely on feedback control of the NO_x concentration in the net flue gas due to the lack of measurement points for NO_x concentration in the furnace outlet and the high dust content in the flue gas. In order to solve Longstanding problems such as low automation input rate, large ammonia escape and poor control effect in SNCR denitrification system of CFB boiler, this paper presents an optimal control strategy based on model predictive control(MPC) technology. The control strategy includesfeedforward control and feedback control. The feed for ward control variables include flue gas oxygen content and main steam flow. The feedback control variable is net flue gas NO_x concentration. The model predictive controller is used to replace the PID controller, and the step response model relationships between related variables are established. Firstly, the SIMULINK simulation software was used to build a simulation model for the denitrification system. Then, the historical data of disturbance variables such as load and oxygen content were imported into the model. Finally, the simulation of denitrification control effect, the simulation of oxygen measurement point blowing, and the simulation of net flue gas NO_x concentration measurement point blowing were carried out. The simulation results indicate that the actual value of the net flue gas NO_x concentration fluctuates within the range of ±5 mg/m~3 of the set value, and during the blowing period of the oxygen measurement point, disturbance variable was only the main steam flow to enhance control system anti-jamming capability, and the blowing of the NO_x concentration measurement point of the net flue gas has little impact on the control system. The control strategy is applied in the SNCR denitrification system of a 280 t/h high-pressure CFB boiler, which spray gun is far away from the ammonia generation equipment. The SNCR control system could not be put into automatic operation because of significant delay. The engineering results indicate that the fluctuation amplitude of NO_x concentration in the net flue gas was significantly reduced to within ±5 mg/m~3,the ammonia injection was locally adjusted with feedforward control variables such as oxygen content and main steam flow. The overall trend of the ammonia injection was adjusted with the NO_x concentration in the net flue gas. The ammonia injection amount could quickly increase to the highest point and slowly decrease when the load changed. The fluctuation amplitude of ammonia injection amount was significantly reduced compared to manual operation. The average concentration of NO_x in the clean flue gas had increased from 30 mg/m~3 to 42 mg/m~3. The ammonia injection amount was reduced by more than 8%.The MPC technology has achieved good results in the SNCR denitrification control system.

    2024 S2 v.30 [Abstract][OnlineView][Download 520K]

  • Carbon quota surplus and deficit characteristics of power unit undercarbon market

    SUN Youyuan;SONG Mingguang;LIU Yifang;WANG Jing;GANG Ling;Huadian Electric Power Research Institute Co.,ltd.;

    In order to study the carbon quota surplus characteristics of the power unit, the carbon quota surplus per unit power supply was established based on carbon emission accounting methodology and carbon quota allocation mechanism, and the influencing factors were divided into three categories: operation attribute parameters, carbon emission attribute parameters and coupling attribute parameters. Then the contribution of element carbon content, fly ash carbon content, slag carbon content and standard coal consumption of power supply were analyzed. The results show that the contribution of element carbon content to carbon quota surplus per unit power supply and carbon benefits per unit electricity is the largest, when it increases by 1%,it contributes-0.022 8 t/(MW·h) to the carbon quota surplus per unit power supply, and-0.680 0 ￥/MWh to the carbon benefits per unit electricity; the contribution degree of standard coal consumption is the second, when it increases by 0.005 0 t/(MW·h),it contributes-0.015 0 t/(MW·h) to the carbon quota surplus per unit power supply, and-0.470 0 ￥/(MW·h) to the carbon benefits per unit electricity, and the contribution degree gradually decreases with the decrease of carbon emission attribute and coupling attribute parameters; the contribution degree of fly ash carbon content and slag carbon content is small. Finally, some suggestions on carbon quota management are given, which provides a reference for carbon emission management of power generation enterprises.

    2024 S2 v.30 [Abstract][OnlineView][Download 260K]

  • Optimization of supercritical boiler combustion using improved extreme learning machine for low-quality coal firing

    SUI Bingwei;ZHAO Xiaopeng;CHAO Junkai;XU Dapeng;Ningxia Jingneng Ningdong Power Generation Co.,Ltd.;

    The prevalence of burning inferior coal in coal-fired boilers has led to increasingly significant economic and environmental issues. Existing research on the combustion of inferior coal in boilers has primarily focused on individual economic parameters such as boiler fly ash carbon content, flue gas temperature, or NO_x emissions. However, these studies have overlooked the holistic economic optimization of boiler operation, potentially leading to trade-offs between different aspects.This paper employs an improved Extreme Learning Machine algorithm to construct a predictive model of a 350 MW ultra-supercritical boiler burning inferior coal. Additionally, an overall economic evaluation method for the operation of ultra-supercritical boilers is established, which forms the basis for optimizing the boiler's overall economic performance. The results indicate that the heating value of coal, primary air rate, and oxygen content have high impact on the flue gas temperature and carbon content of fly ash in the boiler, with their contributions exceeding 10%. Consequently, the study further explores the influence and optimization measures of these factors on the overall economic performance of the boiler. As the heating value of coal increases, the operational cost of the boiler first decreases and then increases, indicating the existence of an optimal heating value. Within the scope of calculation for the boiler studied in this paper, the operational cost increases with an increase in primary air rate. Moreover, there is an optimal value of furnace oxygen concentration under different loads. The proposed boiler operation prediction algorithm and economic optimization model in this study offer a novel approach to optimizing the operation of ultra-supercritical boilers.

    2024 S2 v.30 [Abstract][OnlineView][Download 459K]

  • Influence of particle characteristics on the measurement of particle mass concentration using light scattering method

    MA Zhian;LIU Xiu;DONG Fang;CHEN Dong;ZOU Yue;LIU Xiaowei;Huadian Electric Power Research Institute Co.,Ltd.;Cummins East Asia R&D Co.,Ltd.;College of Energy and Power Engineerign Huazhong University of Science and Technology;

    Light scattering is an important method for measuring the mass concentration of particulate matter. This study investigates the differences in mass sensitivity of fly ash particles from different emission sources at various scattering angles and finds that at a 25° scattering angle, the relative mass sensitivity decreases in the following order: coal-fired power station fly ash particles, waste incineration fly ash particles, biomass combustion fly ash, road dust, and carbon black particles. By analyzing the composition, particle size, and morphology of actual ash particles, it is found that the mass sensitivity of actual ash particles is greatly affected by the composition. Generally, fly ash particles with higher concentrations of Al elements have higher relative mass sensitivity. Fly ash particles with higher concentrations of Fe elements or organic components have lower relative mass sensitivity due to their stronger light absorption ability. This study can effectively guide the online monitoring of the mass concentration of particulate matter from different emission sources using the light scattering method.

    2024 S2 v.30 [Abstract][OnlineView][Download 2185K]

  • Real-time optimization of key parameters of complex heating system in coal-fired power station

    LI Maoqin;XUE Xiaojun;TAILAITI Tuerhong;Jilin Electric Power Co.,Ltd.;School of Electric Power and Architecture,Shanxi University;College of Energy and Power Machinery Engineering, North China University of Electric Power;

    To improve the heating economy of a complex heating system of a coal-fired power station, taking the best back pressure and the best extraction steam flow of the complex heating system as the starting point, big data analysis method is adopted to screen and process the historical operating data of the heating system. Meanwhile, random forest algorithm is used to establish a coal consumption prediction model of each heating unit of the power station to predict the real-time coal consumption of the system. The optimal operating parameters corresponding to the minimum coal consumption of the heating system under different working conditions can be obtained by using the historical data, that is, the optimal back pressure and the optimal extraction steam flow. Under the premise that the total heat supply and total power generation of the whole plant remain unchanged, the total coal consumption of the whole plant can be reduced by 0.8～3.0 tons of standard coal/hour on average through the real-time optimization of the model. The results show that the optimization results obtained by simulation are relatively stable, and the appropriate reduction of back pressure by 7-12.5 kPa is conducive to reducing the overall coal consumption of the system. The optimization and energy-saving effect of the whole heating system is more significant at low load.

    2024 S2 v.30 [Abstract][OnlineView][Download 460K]

  • Economic analysis of large-scale hydrogen storage based on storage pressure optimization of hydrogen storage system

    NIU Tianyu;JIANG Yan;China Electronics Engineering Design Institute CO.,LTD;

    The cost of hydrogen compressor and hydrogen storage vessel exceeds 50% of equipment investment of hydrogen refueling station, and storage pressure has a profound effect on their selection and the economy of this system. In order to study cost-effective hydrogen storage, which can meet the demand of producing hydrogen from renewable electricity system, the impact of different hydrogen storage pressure on the compressed energy consumption and initial investment of hydrogen energy storage system is studied. Five levels of hydrogen storage pressure are selected between 3 and 45 MPa, which are 12,17,20,25 and 30 MPa, respectively. It is found that 20 MPa can be used as the intermediate hydrogen storage pressure after comprehensive analysis. And the levelized cost of hydrogen energy storage shows a rapid downward trend with the increase of hydrogen storage capacity, which means it is suitable for large-scale energy storage scenarios. It is also found that hydrogen energy storage is sensitive to electricity price due to the large power consumption and the lower system efficiency of the water electrolysis process in the "electricity-hydrogen-electricity" system.

    2024 S2 v.30 [Abstract][OnlineView][Download 197K]

  • Ultra-low load NOx control of coal-fired boiler based on flue gas recirculation

    LIU Wensheng;ZHENG Jianping;ZOU Yufeng;TONG Jialin;CHEN Xiaobo;YE Xuemin;Hangzhou E-Energy Technology Co.,Ltd.;North China Electric Power University;

    Aiming at the phenomenon of excessive NO_x generation in a 600 MW tangentially-fired boiler under ultra-low load, four sets of flue gas recirculation schemes were proposed, including mixing flue gas into primary air, secondary air, and primary/secondary air respectively. The effects of the change of excess air coefficient and the change of the position of mixed flue gas on temperature field, composition field, pulverized coal burnout rate and NO_x emission reduction rate were compared and analyzed by numerical simulation method, to determine the best scheme for reducing NO_x emission based on flue gas recirculation under ultra-low load. The results show that the flue gas recirculation technology can effectively reduce NO_x emission, and with the increase of flue gas recirculation rate, the NO_x concentration at the furnace outlet decreases significantly. In the secondary air flue gas recirculation, the reduction of excess air coefficient is more helpful to improve the furnace outlet flue temperature and reduce NO_x generation. Through the comparison of the primary and secondary air flue gas recirculation rates, it is found that the primary air flue gas recirculation has a better effect on NO_x emission control, while the secondary air flue gas recirculation is more helpful to improve the furnace outlet flue temperature. Under ultra-low load, when the flue gas recirculation rate in the primary and secondary air is 5%+15%,the NO_x concentration at the furnace outlet is as low as 212.5 mg/Nm~3,and the NO_x emission reduction rate is up to 32.7%. To ensure combustion stability and pulverized coal burnout rate at 20% rated load, it is recommended that the flue gas recirculation rate of primary and secondary air be 5%+10%.

    2024 S2 v.30 [Abstract][OnlineView][Download 4244K]

  • The effect of flue gas drying of desulfurization wastewater on the concentration of heavy metals in desulfurization wastewater and fly ash

    YANG Jianguo;ZHANG Yiqin;WEI Tingfan;WU Zhepeng;LI Min;LIANG Yinhe;CUI Qingwei;State Key Laboratory of Clean Energy Utilization,Zhejiang University;Jiaxing Research Institute of Zhejiang University;Zhejiang Zheneng Lanxi Power Generation Co,Ltd;

    One of the main methods to achieve zero discharge of desulfurization wastewater is to spray desulfurization wastewater back into the flue and steam it dry. Dechlorination of flue gas can reduce the amount of desulfurization wastewater, thereby improving the impact of a large amount of desulfurization wastewater spray on equipment. Desulfurization wastewater contains a large amount of chloride ions and various heavy metals. After being evaporated and dried in the flue, some of the solid particles formed are removed by the dust collector, and the rest will enter the desulfurization system again. After multiple cycles, heavy metals may accumulate in the desulfurization wastewater. A model is established based on a 660 MW unit, and the influence of changes in desulfurization wastewater flow rate and the migration behavior of solid particles formed by desulfurization wastewater evaporation on the concentration of heavy metals in desulfurization wastewater and fly ash is analyzed by considering the changes in dust removal rate and flue gas dechlorination efficiency. The following conclusions are drawn: under the condition of controlling the chloride ion concentration of desulfurization slurry to be constant, affected by the removal rate of the dust collector, the recycling of desulfurization wastewater will lead to an increase in the flow rate of desulfurization wastewater; When the flue gas dechlorination efficiency is 70%,the removal rate of the dust collector increases or decreases by 5% on the basis of 90%,and the flow rate of desulfurization wastewater changes by-5% and 6% respectively. The magnitude of heavy metal concentration changes in desulfurization wastewater can be ignored; Dechlorination of flue gas can cause the concentration of heavy metals in desulfurization wastewater to increase by more than three times. However, all desulfurization wastewater is internally recycled, and heavy metal enrichment is not a key issue; The increase in heavy metal concentration brought to fly ash by desulfurization wastewater after being sprayed back into the flue is basically less than 1%,and the impact on fly ash quality can be almost ignored.

    2024 S2 v.30 [Abstract][OnlineView][Download 1052K]

  • Rheological performance analysis and pipe transport characteristics simulation of gangue slurry containing coarse particles

    CHENG Lei;XIAO Gang;WANG Danying;GAO Weiwei;HE Jun;WANG Shi;Shaanxi Coal Industry Company Limited of Caojiatan;China Coal Land Ecological Environment Technology Co.,Ltd;School of Resources & Environment Engineering,Jiangxi University of Science and Technology;

    The coarse particle content can significantly affect the rheological properties and pipeline transport performance of the filling slurry. In this paper, the rheological characteristics of the gangue slurry containing different gangue coarse particles were tested, and the numerical simulation of the pipe transport characteristics was carried out on this basis. Test and numerical simulation results show that: with the increase of gangue coarse particles, fine gangue powder particles since the formation of the flocculation network structure strength weakened, resulting in the gangue slurry yield stress and plastic viscosity reduced. During the pipeline transmission, the gangue slurry gradually transitioned from unstable flow to structural flow, and the higher coarse particle content induced the formation time of structural flow to be pushed back. Moreover, the coarse particle content significantly influenced the volume fraction distribution of the gangue slurry. The homogeneity of the gangue slurry containing less coarse particles was higher, while too much coarse particle content led to the accumulation of a large number of particles at the bottom of the pipe, and the homogeneity of the slurry was significantly reduced and prone to plugging accidents. The resistance loss of the gangue slurry obtained based on the pressure drop decreased with the increase of coarse particle content. Comprehensive consideration of coarse particles on gangue slurry rheology, stability, volume fraction distribution and resistance loss, the recommended coarse particle content should not be higher than 30%.

    2024 S2 v.30 [Abstract][OnlineView][Download 4195K]

  • Research on the treatment of coal processing plant wastewater by copolymer flocculants

    HU Jinliang;ZHAO Peng;ZHANG Yanfu;SHANG Shuhong;Science and Technology Research Institute of CHN Energy Zhunneng Group Co.,Ltd;Zhunneng Coal Prenaration Plant of CHN Energy Zhunneng Group Co., Ltd;

    The wastewater from coal preparation plants contains various metal ions and chemicals. If not properly treated, it will cause serious problems to the ecological environment and lead to discharge. The purpose of this study is to obtain qualified circulating water for production use and eliminate the impact of coal slurry water from coal preparation plants on the surrounding environment. For this purpose, four different molecular weight anionic flocculants and one non-ionic flocculant were used to conduct laboratory flocculation experiments on the coal slurry water of the coal preparation plant, establish the optimal settling conditions, and design wastewater treatment facilities. The research results provide feasible solutions for wastewater treatment in coal preparation plants.

    2024 S2 v.30 [Abstract][OnlineView][Download 1160K]

  • Experimental study on static anti-segregation performance of fine coal gangue slurry under different mass concentrations

    DING Weibo;CHENG Lei;GAO Tianxiang;LI Qingnian;WU Rui;Shaanxi Shanmei Caojiatan Mining Co.Ltd.;China Coal Land Ecological Environment Technology Co.Ltd.;School of Resources & Environment Engineering,Jiangxi University of Science and Technology;

    In order to characterize the static stability of fine-grained coal gangue slurry at different mass concentrations, the static force of solid particles was analyzed according to solid-liquid two-phase fluid mechanics and non-Newtonian fluid mechanics, and the static anti-segregation mechanical model of coal gangue slurry was constructed. Considering the static yield stress of the slurry, the particle size composition of the solid particles and the solid-liquid density, a static stability characterization model was proposed, that is, the static segregation judgment value M. In this paper, the static stability of fine-grained coal gangue slurry was studied. The coal gangue slurry with different mass concentrations was prepared with water cement ratio as a single factor, and the related experiments of slurry consistency, density and bleeding rate were carried out. With the aid of slurry rheometer, the static yield stress τ_s of coal gangue slurry was measured by controlling shear rate mode, and the experimental results were fitted and analyzed. The results show that the mass concentration of coal gangue slurry is linearly positively correlated with consistency and density. The bleeding rate decreases gradually with the increase of slurry mass concentration, and the decrease rate gradually slows down, and the slurry performance tends to be stable. At the same mass concentration, the characterization results of M_(min),M_(avg) and M_(max) of fine-grained coal gangue slurry static segregation judgment values are quite different, indicating that the three have different accuracy. When the static segregation characterization model is used to predict the static stability of fine-grained coal gangue slurry, the maximum particle size is the best choice for solid particle size. At this time, the static stability of coal gangue slurry can be accurately predicted by using the static segregation judgment value M_(max),and the multiple correlation coefficient is 0.983. The mass concentration range is 53.80%～65.34%,the slurry consistency is greater than 12.9 cm, the density is 1 497-1 663 kg/m~3,and the bleeding rate is 2.27%-14.20%.

    2024 S2 v.30 [Abstract][OnlineView][Download 297K]

  • Evaluation of the stability of different coal mills in a 660 MW unit

    MAO Chenghui;DONG Zhuyu;CHN energy Hunan electric power company limited;School of energy,power and Mechanical Engineering,North China Electric Power University;

    The operating status of the coal mill affects the stability and safe operation of the unit. This article conducts a comprehensive evaluation of the stability of six coal mills in a certain power plant based on big data. First, the 3σ criteria are used to distinguish the outlier of the data, and use the sliding pane method to screen and extract the data under the stable state; Subsequently, the process capability index and coefficient of variation were used to evaluate by C_(pk) and C_V for the stability under full load and steady load; Finally, the order relationship analysis method(G1) was used to calculate the weights of different indicators, and the TOPSIS method was used to comprehensively evaluate the stability of different coal mills. The results show that the stability of key parameters of #2 mill and #4 mill is better and that of #6 mill is worse under full load and steady load conditions; and the stability level of parameters increases with the increase of load under steady load condition. Under full load, the C_(pk) value of the coal mill separator air-powder mixture temperature of the #2 mill separator is 1.30,while the C_(pk) value of the #6 mill is only 0.73;under steady load, the C_V value of the primary air temperature of the #2 mill at high load is 0.04,while the C_V value of the #6 mill is 0.11. The comprehensive evaluation results of different mills show that #2 and #4 mills have better performance and higher stability scores, while #5 and #6 mills have relatively poor stability levels. The stability evaluation method of the coal mill proposed in this paper can reasonably and effectively reflect the operating status of the coal mill.

    2024 S2 v.30 [Abstract][OnlineView][Download 2419K]

  • Research and application of sodium polytungstate heavy liquid in coal flotation and sinking

    WANG Zhigang;XU Renfeng;YANG Lidong;KANG Yuntao;Shenhua Zhunneng Energy Co.,Ltd;School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing;

    For the traditional coal flotation of zinc chloride(ZnCl_2) heavy liquid appeared “large amount, corrosive, toxic”and other outstanding problems, proposed a safe, non-toxic, easy to configure, strong stability, flotation and sinking sorting effect, can be used for coal flotation of a new inorganic heavy liquid. It was found that the density of sodium polytungstate heavy liquid at room temperature was less changed by metal ion concentration and heavy liquid viscosity. The results show that the product ash content of sodium polytungstate is higher than 1.8 g/cm~(3 )when used as heavy liquid and the cumulative yield of floating is higher than heavy liquid in low density heavy liquid environment. The product morphology and elemental content of sodium polytungstate after floating and sinking further indicate the obvious effect of sodium polytungstate heavy liquor, and these studies provide a theoretical basis for the new environmentally friendly agent to replace ZnCl_2 heavy liquor for coal floating and sinking.

    2024 S2 v.30 [Abstract][OnlineView][Download 1854K]

  • Application oflow-temperature flash evaporation concentration coupled bypass drying technology for zero discharge of desulfurization wastewater

    WANG Feng;XU Yongyi;LIU Tingan;WU Xiaoqin;DONG Weiru;China Power Hua Chuang Electricity Technology Research Co.,Ltd.;

    The process selection and operation of desulfurization wastewater zero discharge of a new 2×350 MW coal-fired unit are introduced. The power plant uses urban recycled water as the water source, and selects the process of “non-softened low-temperature flash evaporation concentration+high-temperature bypass drying”to realize zero discharge of wastewater. The modified process mainly includes flue gas heat exchange unit, low-temperature flash evaporation unit, and concentrated liquid drying unit, etc. The results show that the process has the characteristics of simple structure, no pretreatment, and full utilization of waste heat from flue gas, which can meet the requirements of zero emission treatment for small capacity of units and large amounts of desulfurization wastewater. The investment cost of zero emission equipment is 1.15 million yuan/m~3, and the treatment cost is about 25 yuan/t. The operating cost of this technology is relatively low, and it has the significance of promotion and demonstration.

    2024 S2 v.30 [Abstract][OnlineView][Download 202K]

  • Study on the wettability of coal dust based on different degrees of metamorphic degree of pore structure and fractal characteristics

    WU Yan;KONG Linpo;HU Weiwei;Research Institute of Coal Chemistry,China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;China University of Geosciences;

    N_2 adsorption/desorption isothermal experiment and surface fractal theory were used to study fractal characteristics of pore structure of coal dust with different metamorphism. The wettability of coal dust with different metamorphism in water and 0.1%OP-10 aqueous solution and 0.1% X-100 aqueous solution was studied by contact angle measuring instrument and coal dust settling velocity measuring method, and the influence of surface fractal dimension on coal dust wettability was analyzed. The results showed that in the process of changing from low rank lignite to high rank anthracite, with the increase of metamorphism, the pore structure of coal changes from simple to complex. The five kinds of coal dust were mainly mesopores and macropores, and SL lignite coal dust had the highest mesopores and macropores, while TX anthracite coal dust had the lowest mesopores and macropores. The surface of coal dust with different metamorphic degrees was very rough and complicated. The fractal dimension of coal dust surface was in good agreement with the proportion of micropore area and micropore volume, and it showed an opposite trend to the specific surface area of coal dust. From lignite to bituminous coal, surface fractal dimension increased and wettability decreased; When anthracite was used, the surface fractal dimension decreased and the wettability increased. The wettability of bituminous coal was improved by surfactant solution, followed by anthracite and lignite.

    2024 S2 v.30 [Abstract][OnlineView][Download 550K]

  • Application of domestic reconstruction of LINEAR vibration screen discharge box in coal preparation plant

    LI Jinsan;National energy Shendong Coal Co.,Ltd.washing Center;

    Vibrating screen is an important production equipment in coal preparation plant, In charge of coal material classification, dewatering, desliming and demediating in production process.After the LINEAR vibrating screen has been installed and operated for a period of time, cracks often occur in the structural parts of the equipment due to improper design and installation, inadequate daily maintenance, overloading and fatigue operation, etc.,the frequent cracking and abrasion of the vibrating screen outlet box lead to the abnormal operation of the vibrating screen, which seriously affects the daily production and reduces the production efficiency of the coal preparation plant.According to the structure and working principle of the vibrating screen, this paper deals with the frequent cracking and easy wear of the vibrating screen discharge box, an analysis of the causes, treated by special welding, and problems in the welding process, combined with the actual welding effect on site, through optimizing the installation structure, connecting and fixing way, reducing the whole weight, changing the material in the worn area and selecting the wear-resisting connecting parts, the solution to the frequent cracking and easy wearing of the discharge box is discussed.After the application of the new technology, the frequent cracking and easy wear accidents of the discharge box are obviously reduced, and the effect is remarkable.

    2024 S2 v.30 [Abstract][OnlineView][Download 332K]

  • Application of intelligent inspection robot in belt conveyor of coal preparation plant

    NAN Chaoyun;National Energy Group Shendong Laundry Center;

    In view of the problems existing in the inspection of the belt conveyor in the coal preparation plant, such as protection misoperation, inadequate patrol inspection and no standard record, this paper analyzes the characteristics and inspection requirements of the belt conveyor, introduces the application system of the intelligent patrol robot of the belt conveyor, uses the intelligent patrol robot to patrol the relevant facilities and equipment in the area, accurately collects the environmental data, equipment working conditions and other information, and realizes the abnormal early warning, fault diagnosis Early warning and other functions; It solves the problems that the inspection of belt conveyor can not be recorded and quantified accurately; Digital image, sound and accurate data rules are used for real-time storage to realize the unattended, automatic detection and automatic reminder functions of the belt conveyor in the coal preparation plant; This paper discusses the feasibility of the intelligent detection robot to detect the running state of the equipment, expounds the problems existing in the detection process of the intelligent detection robot, improves the intelligent management level of the belt conveyor, and has important significance for the staff to improve work efficiency, save energy and reduce consumption.

    2024 S2 v.30 [Abstract][OnlineView][Download 534K]

  • Data driven prediction model of dense coal preparation based on eural network with Prey-Predator optimization

    ZHANG Yunfei;National Energy Investment Group Shendong Coal Group Co.,Ltd.;

    Aiming at the problems of complex dense medium coal preparation process, strong nonlinearity and difficult mechanism modeling, a prediction model of ash mass fraction in clean coal based on industrial data was established by combining the global optimization ability of Prey-Predator optimization(PPO) algorithm with the nonlinear mapping ability of neural network(NN). By transforming the connection weight and threshold value of NN into the feasible solution in the PPO algorithm, and then updating the feasible solution through the algorithm, the network weight and threshold which can make the difference between the output of the prediction model and the real value minimum can be found. The effectiveness of the method is verified by experiments, and the ash prediction model based on PPO-NN is superior to the traditional NN in several operational indicators, such as root mean square error, mean absolute error, R Squared operational indicators.

    2024 S2 v.30 [Abstract][OnlineView][Download 326K]

  • Relationship between hydrophobic tail chain configuration of nonionic surfactant and wettability of low rank coal dusts

    KONG Linpo;WU Yan;MA Bowen;Research Institute of Coal Chemistry,China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;

    In order to study the influence of the interaction between the molecular configuration of surfactants and the physical properties of low-rank coals on the wettability of coal dust, four kinds of low-rank coal dust were researched, and the basic physical properties and wettability of coal dust were studied by means of coal quality analysis, FT-IRand contact angle measurement. The molecular structure, main functional groups and other structures ofthree nonionic surfactants were characterized by FT-IR analysis. The interaction mechanism between hydrophobic tail chain structures and properties of surfactants and hydrophobic groups of coal dusts were studied by coal dust settling experiment, and the influence on coal dust wetting and settling was discussed. The results showed that the order of wettability of the four coal samples was NMH<YL<DS<SL,SL,DS and YL,the higher the ash content, the better the wettability. The poor wettability of NMH coal was due to the most hydrophobic alkyl side chains. There was no obvious linear relationship between the aromatic ring structure content and coal dust wettability(in aqueous solution). Because the surface energy of linear alkyl was larger than that of branched alkyl, n-AEO-9 had the lowest ability to reduce surface tension and wet coal dust. The wetting performance of different coal dust was different between i-AEO-9 and OP-9 with aromatic ring. For NMH,SL and YL coal dust, i-AEO-9 had the best wetting effect, and DS coal dust had strong π-π interaction with the aromatic ring structure in the hydrophobic tail chain of OP-9,so OP-9 had the best wetting effect.

    2024 S2 v.30 [Abstract][OnlineView][Download 225K]

  • Efficient flocculation and sedimentation experiment of APAM-PAC on coal gangue powder suspension with high solid content

    DING Weibo;WANG Rui;CHENG Lei;RUAN Zeyu;XU Jinhai;Shaanxi Coal Industry Company Limited of Caojiatan;China Coal Land Ecological Environment Technology Co.,Ltd;China University of Mining & Technology-Beijing;

    The coal gangue powder contains some microfine particles suspended in the draining water of the filling slurry, forming a coal gangue powder suspension that is difficult to settle, which seriously affects the efficiency of sewage treatment and filling. In order to study the flocculation and sedimentation characteristics of coal gangue powder suspension, anionic polyacrylamide(APAM) and polymeric aluminum chloride(PAC) were used to carry out the flocculation and sedimentation experiments of coal gangue powder suspension under different unit consumptions of flocculants. The results showed that the flocculation sedimentation efficiency of coal gangue powder suspension increased first and then decreased with the increased of addition unit consumption of APAM. When the unit consumption of APAM was 0.5 kg/t, the maximum sedimentation rate was 64.28 cm/min, and the sedimentation end time was 1min. APAM-PAC composite effect can significantly improve the flocculation and sedimentation efficiency of coal gangue suspension, and the sedimentation efficiency of coal gangue suspension increased with the increased of unit consumption of PAC under the same addition unit consumption of APAM and then decreased. When the unit consumption of APAM was 0.5 kg/t and unit consumption of PAC was 24 kg/t, the maximum settling velocity was 3.43 times that of adding APAM only, the settling time was shortened to 0.75 min, and the settling efficiency was the highest.

    2024 S2 v.30 [Abstract][OnlineView][Download 405K]

  • Flow and diffusion characteristics of coal gangue slurry during the high and low-levelgrouting process in goaf areas

    DING Weibo;RUAN Zeyu;CHENG Lei;GAO Tianxiang;HE Jun;WU Rui;Shaanxi Coal Industry Company Limited of Caojiatan;CNACG Ecological Environment Technology Co.,Ltd.;School of Resources and Environmental Engineering,Jiangxi University of Science and Technology;

    Coal gangue slurry filling the collapsed area of mining area can not only effectively solvethe safety problem of underground operation, but also can dispose a large amount of coal gangue solid waste piled up on the surface. To find out the diffusion law of coal gangue slurry is the key to whether it can effectively fill the collapsed rock layer, maintain the stability of the mining area and realize the green and harmless treatment of coal gangue.A small slurry model is established in the background of the actual mine, and the gangue slurry injection test with different mass concentration and particle size is carried out to analyze the effect of different roller mill gangue particle content of low level slurry and different mass concentration of high level slurry on the slurry diffusion radius and self-flow slope. The results show that the gangue slurry under the two injection methods are first longitudinal expansion and then lateral diffusion evolutionary law. Meanwhile, increasing the content of roller mill gangue within the gangue slurry reduces the self-flow slope of the slurry, increases the diffusion radius and filling volume of the slurry, corresponding to the enhanced diffusion capacity of the slurry. However, increasing the mass concentration of the slurry increases the self-flow slope of the slurry, decreases the diffusion radius and filling volume of the slurry, and significantly weakens its diffusion performance. The results of the study can provide a reference basis for the analysis of the diffusion characteristics of slurry filling slurry.

    2024 S2 v.30 [Abstract][OnlineView][Download 4968K]

  • Dewatering effect of high-pressure filter slime

    ZHANG Jianhua;ZHANG Guoying;JIRI Gele;SUN Xin;HE Mengqi;MA Jinqing;Shenhua Junneng Group Co.,Ltd.,Coal Preparation Plant;College of Chemical and Environmental Engineering,China University of Mining and Technology;

    Slime dewatering is an important part of the coal washing process. Dewatered slime reduces transportation costs, increases calorific value, and reduces environmental impact. In this paper, the semi-industrial high-pressure diaphragm filter press is used to study the effects of filter press pressure, filter press time, slurry concentration and content greater than 0.045 mm in slime on the dewatering effect of slime. The results show that the increase of filter pressure can significantly reduce the moisture of the filter cake and improve the dehydration efficiency, and when the filtration time is 180 s and the slurry concentration is 300 g/L,the pressure of the filter press increases from 1MPa to 5 MPa, the moisture of the filter cake is reduced from 29.89% to 23.78%,and the initial dewatering rate is increased from 3.5 mL/s to 8.7 mL/s. Under the condition of filter pressure of 3 MPa and filter press time of 180 s, when the particle size content greater than 0.045 mm increased from 25% to 100%,the moisture content of the filter cake decreased from 29.89% to 23.78%,and the initial dewatering rate of the filter press increased from 2.6 mL/s to 6.3 mL/s. The research results provide a test basis for the operation improvement of on-site filter press system in coal preparation plant.

    2024 S2 v.30 [Abstract][OnlineView][Download 3062K]

  • Analysis of improving efficiency and reducing resistance of cyclone separator in a circulating fluidized bed boiler

    WANG Xiaowei;HAN Chengliang;Taiyuan Boiler Group Co.,Ltd.;Department of Energy and Power Engineering,Tsinghua University;

    The cyclone separator is the core component of the circulating fluidized bed(CFB) boiler. Its separation efficiency affects the combustion characteristics and environmental protection characteristics of the boiler, and its operating resistance affects the fan selection and plant power consumption. The efficiency improvement and resistance reduction of the separator are crucial to the CFB boiler. In this paper, a 300 t/h boiler cyclone separator is simulated, and the influence rules of key parameters such as throat flow rate, cylinder diameter, cone length, central cylinder diameter and insertion depth on separator efficiency and resistance are obtained. Based on the simulation results, the structural modification and experimental verification of the separator of the 3 MW CFB pilot test rig were carried out, and the experimental results were consistent with the simulation. The results show that increasing the diameter of the cylinder, the length of the cone, and the insertion depth of the central cylinder can increase the separation efficiency and reduce the resistance. Increasing the flow velocity at the throat can improve the efficiency of the separator, but the resistance increases significantly. And this conclusion is applied to the design of a new generation of boilers, which greatly improves the bed material quality, combustion characteristics and environmental protection characteristics of the boilers.

    2024 S2 v.30 [Abstract][OnlineView][Download 2419K]

  • Mathematical model analysis of coal slurry dewatering influencing factors

    LEI Xiaoshu;SUN Xin;HE Mengqi;MA Jinqing;Coal preparation plant Shenhua Junge Energy Co.,Ltd.;College of Chemical and Environmental Engineering,China University of Mining and Technology;

    Slime dewatering is an important part of the coal washing process. Dewatered slime reduces transportation costs, increases calorific value, and reduces environmental impact.The mathematical model analysis of the comprehensive influence of semi-industrial high-pressure diaphragm filter press on slime dewatering is carried out, and the Konzeni equation is selected for analysis through the study of the slime filter dewatering process, and the filtrate volume is used instead of the filter cake resistance, and the Kocsenny equation is simplified by calculus and linear fitting, so as to obtain the filtrate volume-time expression at a specific pressure:(q+160.78)2=14 894.36(t-8.01) and then study the dewatering process of press filtration. The research results provide a test basis for the operation improvement of on-site filter press system in coal preparation plant.

    2024 S2 v.30 [Abstract][OnlineView][Download 1984K]

  • Optimization of mill ventilation measurement based on forced vortex theory

    ZHOU Chuang;LIU Weiqi;WANG Jinzhu;SUN Shouming;GUAN Duojiao;DAI Xinyao;PU Jianye;CPI Northeast Energy TechnologyCo.,Ltd.;School of Energy and Power, Shenyang Institute of Engineering;National Energy Group Shuangyashan Power Generation Co.,Ltd.;

    The ventilation capacity of the coal mill in thermal power units cannot be accurately measured, which seriously affects the safety and economic operation of the unit. In order to realize the accurate measurement of the ventilation volume of the coal mill, the distribution law of the flow and pressure at the elbow of the coal mill inlet was numerically studied by combining the bending streamline theory in fluid mechanics and applying the numerical calculation method, and the relationship between the ventilation volume of the coal mill and the pressure difference between the inside and outside of the elbow of the coal mill inlet was analyzed. Combining the flow calculation method in the forced vortex theory, analyze the relationship between the flow coefficient and the pressure difference between the inner and outer sides of the bend, in order to improve the accuracy of ventilation measurement for the coal mill. Through analysis, it can be seen that the numerical calculation results are in good agreement with the bending flow theory. The calculated flow coefficient varies linearly with the pressure difference. After linear correction, the maximum deviation between the calculated flow value and the actual value is-1.42%, which basically meets the actual needs of the project. Compared with traditional flow measurement devices, its nonlinearity and accuracy have been greatly improved, and it has certain application prospects.

    2024 S2 v.30 [Abstract][OnlineView][Download 553K]

  • Predictive control for suspension preparation of shallow trough separation process under model mismatch

    ZHANG Huping;JIANG Kunkun;SONG Jun;WEI Wenpeng;LI Xiangzhong;TIAN Yansheng;DONG Liang;DAI Wei;Guodian Jiantou Inner Mongolia Energy Investment Co.,Ltd.;Dadi Engineering Development Co.,Ltd.;Artificial Intelligence Research Institute,China University of Mining & Technology;

    Shallow trough dense media separation process is an important process of coal washing, and the preparation of dense media suspension directly affects the efficiency of shallow trough dense media separation. In this work, a model prediction controller is designed to ensure that the density of dense medium suspension can track the setpoints in the preparation process of shallow trough separation suspension. Secondly, considering the time-varying model parameters and the existence of noise in the suspension preparation process, which may lead to model mismatch problem, an online parameter identification method is further proposed. An adaptive Kalman filter is adopted to eliminate the impact of noise on the data, and the recursive least squares algorithm with forgetting factor is adopted to identify the model parameters, and then adjusted the controller parameters online. Finally, a simulation experiment was carried out on the background of suspension preparation process. The experimental results show that the proposed method can still ensure the density tracking performance of dense media suspension under the condition of time-varying model parameters and noise.

    2024 S2 v.30 [Abstract][OnlineView][Download 1306K]

  • Application of DOAS principle NOx rapid measurement in denitrification system

    ZHANG Junfeng;DING Yanjun;WANG Tiankun;GU Yongzheng;WEI Shuzhou;WANG Dongxu;ZHANG Jingsheng;HAN Tao;CHNSanhe Power Generation Co.,Ltd.;Hebei Coal-fired Power Station Pollution Prevention Technology Innovation Center;Tsinghua University;National Energy Research and Development Center of Carbon Capture,Utilization and Storage (CCUS) Technology for Coal-based Energy;CHN Energy New Technology Research Institute Co.,Ltd.;

    The controlled NO_x parameters are generally time-varying and large hysteresis in the flue gas SCR denitration system, resulting in large fluctuations in NO_x at the outlet of the SCR denitration system and increased ammonia escape, which in turn causes problems such as reduced efficiency of air preheater, increased power consumption of induced draft fan, and increased maintenance cost of air preheater. In view of the requirements for on-line rapid monitoring of SCR process parameters NO_x,the NO_x concentration in flue gas was monitored online by ultraviolet differential absorption spectroscopy combined with in situ sampling to achieve high-fidelity and rapid monitoring of flue gas. Experimental results indicate that the system response time T_(90) is less than 10 seconds, surpassing the traditional extraction-type instruments used in power plants by 115 seconds, and the measurement accuracy meets on-site requirements. The data obtained from this device, when applied to the automatic control of ammonia injection, significantly reduced the fluctuation range of NO_x at the denitrification outlet, from 19.4 to 5.9 mg/m~3,thereby enhancing the overall quality of ammonia injection in the system.

    2024 S2 v.30 [Abstract][OnlineView][Download 1155K]

  • A new method for predicting dynamic coal consumption incoal-fired heating system

    XIE Zhanjun;XING Gang;XU Xianlong;WANG Dongxu;LI Xiaolong;SHA Wenhui;LIU Zirui;WANG Jinxing;Sanhe Power Generation Co.,Ltd.;Hebei Coal-fired Power Station Pollution Prevention Technology Innovation Center;GD Power Development Co.,Ltd.;School of Civil Engineering and Architecture,North China University of Science and Technology;School of Energy,Power and Mechanical Engineering,North China Electric Power University;

    In order to meet the dual requirements of low energy consumption and high flexibility, a comprehensive heating system consisting of heat pump, back pressure steam turbine and two 350 MW coal-fired units were constructed. According to the heat transfer characteristics of the system, the simulation model of the coupled thermal system was established through commercial software(Ebsilon). A dynamic coal consumption analysis method was proposed, which is mainly used in the design and optimization of heating system, and the influence of load change rate and converted load on heating system was determined. Firstly, the coal consumption of the system was divided into the basic coal consumption during steady operation and the dynamic coal consumption during dynamic operation, and the basic coal consumption was related to the thermoelectric load. On this basis, the three-dimensional curved surface relationship of dynamic coal consumption was calculated according to the coupling correlation expression of reduced load, load change rate and dynamic coal consumption compensation coefficient. The example analysis shows that the optimized thermal system model can effectively reflect the dynamic parameter deviation, and further verifies that the dynamic coal consumption analysis method can accurately predict the synergistic effect of the converted load and the load change rate on the system energy consumption.

    2024 S2 v.30 [Abstract][OnlineView][Download 2022K]

  • Analysis of coal quality parameter based on coal surface color

    WANG Wei;WANG Fei;HU Yuxi;YANG Juanli;Daliuta Coal Mine,CHN Energy Group Shendong Coal Group Co.,Ltd.;Information Technology Co.,Ltd.,China Coal Science and Technology Group;

    In order to explore new ways in the field of coal quality monitoring, the color image analysis technology of coal sample surface was introduced, which aimed to realize the non-contact, economical, efficient and real-time online monitoring of core quality parameters such as coal ash, fixed carbon and calorific value. In view of the fact that the on-line monitoring methods widely used in the current market mostly rely on complex and costly independent equipment, the chromaticity information in the color image of the coal sample surface as the basis for coal quality prediction was innovatively proposed. A total of 35 coal samples from seven representative coal mines in Huainan and Huaibei areas were selected to ensure the diversity and representativeness of the samples. Using high-precision image acquisition equipment to obtain color image data of coal samples, and relying on advanced image processing technology, the RGB color space of the image was finely converted into a normalized chromaticity value to eliminate the interference of external factors such as illumination and shooting conditions. Through in-depth analysis of the processed image data, it is found that there is a significant statistical correlation between the blue and red chromaticity values of coal samples and the ash content, fixed carbon ratio and calorific value of coal. This finding provides a solid data support for the rapid prediction of coal quality parameters. This study not only successfully verifies the feasibility of coal sample surface color as an effective index for coal quality prediction, but also provides valuable technical solutions and theoretical basis for the transformation and upgrading of China′s coal preparation industry to the direction of intelligence and automation.

    2024 S2 v.30 [Abstract][OnlineView][Download 542K]

  • Utilization of coal-based solid waste in ecological restoration: Technological advances and risk analysis

    ZOU Shuping;ZHAO Jinsheng;LUO Hao;LIU Huidong;Dananhu No.2 Mine,State Grid Energy Hami Coal Power Co.,Ltd.;State Grid Energy Hami Co.,Ltd.;National Institute of Clean-and-Low-Carbon Energy,CHN Energy;

    Coal as an important energy resource in China, its mining and utilization processes generate a large amount of coal-based solid waste(coal gangue, fly ash, gasification slag, and desulfurization gypsum). The current disposal method of coal-based solid waste, which mainly relies on landfill, has exerted tremendous pressure on the ecological environment and has become an key factor restricting the sustainable development of the coal industry. To achieve the sustainable utilization of coal resources and environmental protection goals, the use of coal-based solid waste for ecological restoration has shown promising potential and is becoming a hot topic in scientific research and engineering practice. This paper reviewed the progress of ecological restoration utilization technologies of coal gangue, fly ash, gasification slag, and desulfurization gypsum in mine pit backfilling, mine land reclamation, agricultural soil improvement, and marginal land development. The environmental risks during the ecological restoration utilization of coal-based solid waste were also discussed. It is recommended that the entire industry intensify its efforts in scientific research and engineering demonstration while placing significant emphasis on the development and implementation of pollution control standards and product standards for the ecological utilization of coal-based solid waste. Central and state-owned enterprises should leverage their advantages in multi-industry integration to lead innovations in business models within the coal-based solid waste ecological utilization sector. Furthermore, it is essential for the government to coordinate these initiatives to collectively advance the synergistic goals of pollution reduction, carbon mitigation, green expansion, and economic growth.

    2024 S2 v.30 [Abstract][OnlineView][Download 270K]

  • Analysis of the impact of the difference in low-voltage ride-through current characteristics between doubly-fed and permanent magnet wind turbine generators on the protection setting of wind farm collection lines

    WANG Wendong;Guohua(Jiangsu)Wind Power Co.,Ltd.;

    In recent years, with the continuous maturation of large-capacity wind turbine technology, the large replacing small wind power transformation projects have been gradually implemented, where a batch of old small-capacity doubly-fed wind turbines have been replaced by large-capacity permanent magnet models. Due to the different low-voltage ride-through current characteristics of different turbine models, it is necessary to conduct a differential analysis of the relay protection settings for the transformed wind power projects in conjunction with the low-voltage ride-through characteristics of different models, and to formulate targeted setting strategies. Based on a large replacing small wind power transformation project, this paper systematically analyzes the differences in low-voltage ride-through current characteristics of doubly-fed and permanent magnet turbine models on the basis of existing research results, and proposes differential recommendations in conjunction with the relay protection settings of the wind farm′s collection lines, effectively integrating the protection settings with the low-voltage ride-through characteristics of different turbine models.

    2024 S2 v.30 [Abstract][OnlineView][Download 1127K]

  • Six integrations high-quality coordinated development of new energy industry system under the goals of carbon peak and carbon neutrality

    ZHANG Jimiao;HAO Xiuqiang;LI Huiqiang;ZHANG Bao;WANG Wei;CHN Energy Technology & Economics Research Institute;

    Under thedouble carbon goal, China's energy structure is constantly adjusting, and has provided new impetus for the deep coordinated development of coal-based energy industry and new energy. Based on the development trend of coal-based energy and the requirements, this paper systematically expounded the concept of a new industrial system with high quality and coordinated development, which consisted of six integration of coal and coal-power integration, coal-power and new energy integration, coal-chemical integration, coal-based industry and transportation integration, coal-based industry and new materials integration, coal-based industry and circular economy integration. This paper analyzed the role of the state in promoting the development of thermal power from the policy level of three reform linkage, coal power capacity price mechanism, coal resource transformation, etc. The paper focused on the material and energy cycle mode among coal, coal power, chemical industry, new energy and new materials, realized the exchange of products or wastes within the industrial park through the most economical and reasonable transportation mode, formed the circular economy industrial chain of coal-based industry, rationally allocates various resources among various industries, effectively uses wastes, and reduced environmental pollution and improves the economic and environmental benefits of enterprises. The paper analyzed the key technical issues of six integrated high-quality coordinated development of energy, put forward the implementation path of reducing carbon, reducing pollution, expanding green, and growing, established the resource concept and development concept of ecological priority, green development, and made overall planning for the collection and utilization of water resources, solid waste, waste heat, etc., to reduce energy consumption and improve the utilization efficiency of energy and materials. This paper extended the long coal-based energy industry chain, developed high value-added products, extends the upstream and downstream products, practiced the integration of wind and fire storage, coal chemical + new energy, new energy + new materials and other new models, and also give full play to the advantages of multi-industrial development cluster. A number of coal, transport, fire, wind, light, hydrogen, new materials and other industries high-quality coordinated development of demonstration parks are being planned and constructed. It is of great significance for China to leap to the new energy industry system under the double carbon goal.

    2024 S2 v.30 [Abstract][OnlineView][Download 743K]
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