• Research progress in regulation of lignin catalytic pyrolysis products

    ZHOU Anning;BAI Zhuangwei;HE Xinfu;ZHANG Huaiqing;SHI Zhiwei;ZHANG Zhi;WANG Junzhe;School of Chemical Engineering,Xi'an University of Science and Technology;Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources;Shaanxi Coal Industry New Energy Technology Co.,Ltd.;

    As an important renewable organic carbon source,lignin's unique three-dimensional cross-linked structure brings rich chemical potential,but also brings problems for its efficient conversion and utilization. Catalytic pyrolysis is an effective means to realize green,low carbon and high value utilization of lignin. In the research field of catalytic pyrolysis of lignin, methane, syngas, light aromatic hydrocarbons and high-performance porous carbon materials have become the high value of the target products. In view of this,the key regulatory roles of various catalysts in the catalytic pyrolysis of lignin were deeply and systematically discussed,focusing on the application of high-value products in the catalytic pyrolysis of lignin. Among them,AAEMs catalysts can be divided into alkali metal salt and alkaline earth metal salt. Although alkali metal salt reduces the liquid phase yield,it increases the yield of phenol and other monophenols,while alkaline earth metal salt increases the liquid phase yield,and has a significant selectivity effect on enhancing phenol. Alkali metal salts contribute to the formation of gaseous products and can improve the selectivity of H_2. Although alkali earth metal salts inhibit the formation of gaseous products,they play an important role in the water-gas conversion reaction. In terms of solid phase products,alkali metal salts are more conducive to improving the yield of biochar than alkaline earth metal salts,and can further optimize its structure and enhance its reactivity. Metal oxide catalysts are mainly divided into acidic and alkaline categories. In the catalytic pyrolysis process of lignin,acid metal oxides can significantly improve the yield of liquid products,show high selectivity to phenol and MAHs,contribute to the generation of CO and CH_4,and inhibit the generation of biomass carbon. Although alkaline metal oxides can inhibit the production of liquid phase products,they can effectively promote the formation of phenol,and play an outstanding role in promoting the formation of gas phase products and optimizing the structure of biochar. The perovskite catalyst has the advantage of cubic equal structure and excellent redox performance. Metal ion doping significantly increased the oxygen vacancy content,improved the selectivity of liquid phase yield with phenol and MAHs,inhibited the decarboxylation and decarbonylation reactions,increased the selectivity of CH_4,and reduced the biochar yield,and the cyclic catalytic pyrolysis stability was good. The catalytic performance of molecular sieve catalyst is related to its acid-base and surface structure. Lignin with high acidity and suitable pore size can promote lignin pyrolysis and recombination,and affect the yield and selectivity of three-phase products. The catalytic performance can be optimized by metal loading or acidizing pretreatment,and the selectivity of the target product can be improved. Low-cost catalysts such as bentonite are also important,whose acidic sites and pore structure affect product selectivity. Combined with molecular sieve,MAHs selectivity can be greatly improved,and it also has unique regulatory effects on gas and solid phase products. On the basis of this, the optimization strategy of catalysts to achieve high value regulation of lignin catalytic pyrolysis products was further proposed. The future development trend was prospected, and it was emphasized that the exploration of new catalysts with synergistic catalysis and their catalytic mechanism should be strengthened to build technical support for the efficient utilization of lignin catalytic pyrolysis products and promote the continuous development of this field.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1772K]

  • Research advancements in co-firing of coal powder and biomass

    WANG Guanglei;SUN Ligang;ZHAO Chuanjin;XIE Bonan;ZHANG Hai;FAN Weidong;Shandong Electric Power Engineering Consulting Institute;School of Mechanical and Power Engineering,Shanghai Jiao Tong University;

    Against the backdrop of the current global commitment to achieving the dual-carbon goals of carbon peaking and carbon neutrality,the question of how to effectively increase the proportion of renewable energy and reduce the reliance on traditional fossil fuels such as coal has become a key issue in the transformation of the energy strategies of countries around the world. Biomass energy,as a renewable resource with great potential, has emerged as a promising avenue with its abundant quantity, widespread availability,convenient storage and transportation. The significant coupling of biomass in coal-fired boilers can effectively reduce emissions of greenhouse gases,nitrogen oxides,sulfur oxides,and other pollutants. Additionally,due to the high volatile content,high reactivity,low ash and sulfur element in biomass,it can be used not only as a direct combustion feedstock but also a coupled fuel with coal powder combustion after gasification. Whether adopting the direct combustion coupled power generation technology or gasification coupled combustion power generation technology,the mainstream direction for the transformation of traditional thermal power plants is evident,given the minimal need for equipment upgrades and the high utilization rate of fuel resources. This paper start from the biomass resources and utilization in China,systematically reviews the current research status of biomass and the direct coupled combustion,as well as the gasification coupled combustion,with the focus on the research on emissions of pollutants,ash accumulation,slagging,and corrosion aspects. Further,we summarize the existing engineering project at home and abroad,and make an evaluation of the future development trend of this technology is evaluated. This work will provide theoretical support for the low-carbon transformation of the thermal power industry.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1905K]

  • Catalytic hydrogenation of CO_2 to olefins by Sr_(1-x)K_xFe_(0.5)Co_yO_3

    CUI Aixin;HOU Yuanhao;WU Man;GUO Tuo;GUO Qingjie;College of Chemical Engineering,Qingdao University of Science and Technology;College of Chemistry and Chemical Engineering,Ningxia University;

    The preparation of light olefins by CO_2 hydrogenation is an important way to alleviate greenhouse effect.Meanwhile,this is of great significance in improving the self-sufficiency rate of light olefin in China.However,the catalyst with high conversion rates and selectivity towards target products is a prerequisite for achieving hi.gh yields.In order to enhance the yield of light olefins,a perovskite catalyst Sr_(1-x)K_xFe_(0.5)Co_yO_3 was prepared by sol-gel method.This kind of catalyst have notable results with a CO_2 conversion rate of 53.73%,a light olefin selectivity of 40.55%,and a yield of 21.79%.The characterization of catalysts reveal that the medium-strong basic sites and oxygen vacancy concentration are enhanced with addition of Co,which promote the activation of CO_2.As a result,the conversion rate of CO_2 has been improved.The Fischer-Tropsch synthesis reaction has been promoted with the doping of K.Thereby,the selectivity of light olefin has been improved.The precipitation of active metal phases,dissociative adsorption of C-O and facilitated subsequent C-C coupling are all enhanced by the co-doped Co/K.Thereby,CO_2 conversion and light olefin selectivity are increased.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1980K]

  • Effect of direct current electric field on OH* radiation luminescence characteristics in methane-oxygen diffusion flame

    WU Jingxuan;GONG Yan;GUO Qinghua;WU Xinyi;SONG Xudong;WANG Fuchen;YU Guangsuo;Institute of Clean Coal Technology,East China University of Science and Technology;State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University;

    Flames are non-equilibrium,weakly ionized plasmas containing a large number of charged particles,excited state radicals and other substances. Numerous studies have shown that the combination of plasma technology and combustion field can significantly shorten the ignition delay time,extend the flammability limit,improve combustion stability and reduce pollutants. Based on the flame spectral diagnostic system and Maxwell simulation of electric field strength, the effects of DC electric field on flame morphology and OH*radiation were investigated. The results show that under DC electric field,the electric field force acted mainly on the root of the flame,and positive ions in the flame were forced to move to the cathode,which is manifested as a stretching in the appearance of the flame. In oxygen-poor combustion of the flame height is positively correlated with the voltage value,whereas in oxygen-rich combustion the flame height fluctuated only in a small range around 35.08 mm with the change in voltage value,which meant the effect of DC electric field on the flame height was more significant in oxygen-poor combustion. Combined with the para-electric effect,the flame width decreased with the increase of the DC field under DC electric field,and its trend remained consistent under different oxygen-fuel equivalent ratios. The peak intensity of OH* did not change significantly when the voltage value was below 3 kV,and the peak intensity of OH* was negatively correlated with the voltage value when it was above 4 kV. In the case of oxygen enriched combustion,the OH* content at 9 kV showed a decrease of about 10% compared to the case with no voltage applied,which meant the DC field promoted the mixing of fuel and oxygen in the radial and axial directions of the flame.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1868K]

  • Effect of micro-mesoporous Y-type zeolite on catalytic upgrading of gaseous tar during coal pyrolysis

    LI Xueqin;YAN Lunjing;LIU Yujie;WANG Meijun;BAO Weiren;CHANG Liping;State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology;College of Chemical Engineering & Technology,Taiyuan University of Technology;

    As a new clean coal conversion process,coal pyrolysis is an effective means to achieve clean and efficient utilization of coal,and is of great strategic significance to the high-quality development of country. Catalytic upgrading of coal pyrolysis volatiles can be an effective way to change the heavier components of tar to higher value-added substances. High value-added Light aromatics such as benzene, toluene, xylene, naphthalene(BTEXN), which is one of the important ways to realize tar resource utilization. The pore structure of Y-type zeolite was regulated by high-temperature water vapor to explore its effect on the yield and distribution of light aromatic hydrocarbons in coal tar of different coal rank. The results show that high temperature hydrothermal treatment can remove the framework aluminum of Y-type zeolite and form micro-mesoporous structure. With the increase of hydrothermal treatment temperature,the number of mesoporous and the mesoporous specific surface area as well as pore volume also increase,but the damage to the structure of zeolite is more serious. 600 ℃ is the best treatment temperature for hydrothermal dealumination of Y-type zeolite. Compared with direct pyrolysis,the total yield of BTEXN increased by 4.2,5.2 and 2.3 times respectively after catalytic upgrading of three kinds of coal by 600HTY zeolite. Micro-mesoporous Y-type zeolite greatly reduces the mass transfer restriction on heavy macromolecular substances of tar,improves the availability of acid sites of zeolite,and significantly improves the upgrading effect of catalyst on tar.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1771K]

  • Numerical simulations of co-firing municipal solid waste with leachate sludge in a moving grate incinerator

    PENG Dan;GAO Tianyu;JIANG Huawei;JING Yubo;CAO Hai;WU Yuxin;Engineering Technology Research Center of Energy Conservation and Environmental Protection for Power Plant of Henan Province,Zhengzhou Electric Power College;College of Mechanical and Electrical Engineering,Qingdao University;Zhengzhou Yingze Environmental Protection & Energy Company Limited;Department of Energy and Power Engineering,Tsinghua University;

    With the continuous increase in urban domestic waste, waste incineration power generation, driven by waste classification and technological progress, has become an important development direction for clean energy power generation due to its environmental and social benefits. Currently, mechanical grate incinerators account for more than 90% of waste-to-energy plants due to their high efficiency and stability. However, there is a lack of research on the impact of co-firing municipal solid waste(MSW) with leachate sludge on incinerator operations both domestically and internationally. Numerical simulations can play a significant role in studying the combustion state in a moving grate incinerator. In this study, taking a 700 t/d reverse-moving grate incinerator as the object, FLIC software and FLUENT software were employed respectively to simulate grate-firing on the moving grate and gas-phase combustion in the combustion chamber. By the numerical simulations, the temperature field and velocity field were obtained, as well as the concentration distributions of different gas components within the incinerator. The simulation results were compared with the actual operating data, and the maximum error did not exceed 10%, verifying the accuracy of the simulation. Based on this, the moving speed of the grate and the mass fraction of leachate sludge were optimized to improve the aerodynamic field and temperature field in the incinerator. Simulation results showed that reducing the moving speed of mechanical grate could improve the combustion state and combustion efficiency. The appropriate mass fraction of leachate sludge could reduce the local high temperature in the combustion chamber and reduce the slagging level caused by the high flue gas temperature near the secondary air nozzle of the rear wall. However, excessive mass fraction of leachate sludge would lead to the extension of the drying section, which made the high temperature zone closer to the rear wall, which is not conducive to the stable operation of the incinerator. Therefore, it is recommended to control the moving speed of mechanical grate at 3.56 m/h and maintain mass fraction of leachate sludge between 2% and 4%.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1663K]

  • Characterization and mitigation of NO_x emissions across a wide load range in supercritical 350 MW circulating fluidized bed boiler

    YANG Jingchi;WANG Jing;WANG Pengcheng;WANG fei;YANG Fengling;Institute of Resources and Environmental Engineering,Shanxi University;National Key Laboratory for Efficient Resource Utilization Technologies of Coal Waste;Engineering Research Center of Ministry of Education for Resource Efficiency Enhancing and Carbon Emission Reduction in Yellow River Basin;Shanxi Pingshuo Gangue Power Generation Limited Liability Company;

    Under the background of “dual carbon”,with the continuous increase of new energy installed capacity,thermal power units are gradually transforming from primary power sources to auxiliary service power sources. Due to the intermittent nature of new energy,thermal power units need to frequently change loads to maintain grid stability in the form of deep peak shaving. In order to solve the common problem of NO_x emission control under low load during deep peak shaving,this paper takes a certain supercritical 350 MW circulating fluidized bed boiler as the research object,analyzes the operating data of the boiler unit under deep peak shaving conditions,and comprehensively investigates the influence of various factors such as bed temperature,coal type characteristics,and sulfur fixing agent addition on NO_x mass concentration,and explores the NO_x emission characteristics and influencing mechanisms under variable load and low load conditions. Research has found that changes in bed temperature are positively correlated with load,and the oxidation of volatile nitrogen is significantly weakened when the temperature decreases,reducing the generation of NO_x; but as the boiler load continues to decrease,in order to maintain the fluidized state,the excess air coefficient in the dense phase zone increases,resulting in a relatively higher NO_x concentration compared to medium to high loads; when using coal with higher sulfur content simultaneously, the amount of limestone required for desulfurization in the furnace increases,and the effect of promoting NO_x becomes more significant. To control ultra-low NO_x emissions,zone based low nitrogen combustion technology and upper secondary air SNCR denitrification technology are used for regulation. Refine and rationalize the control of coal feeding and air distribution in low nitrogen combustion zones,and match the fuel and air quantities reasonably to achieve precise control of NO_x; the secondary air SNCR retrofit technology sprays reducing agents at more suitable locations to keep the denitrification reaction within a reasonable temperature range, thereby improving denitrification efficiency. The results indicate that these two technologies can effectively control NO_x emissions under low load conditions,providing a feasible technical path for thermal power generation units to maintain stable operation in the context of frequent fluctuations in new energy. This is of great significance for achieving lower emission levels and ensuring stable operation of the power grid. The study confirms that employing zoned low-NO_x combustion strategies or denitrification techniques such as secondary air SNCR can effectively reduce NO_x emissions during low-load operations,thereby addressing this environmental challenge in the power generation industry.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1489K]

  • Rice husk/coal tar pitch based hierarchical porous carbons as the cathode of zinc ion hybrid capacitors

    PENG Guodong;ZHU Aoyang;ZHU Yiquan;LI Yong;HE Xiaojun;School of Chemistry and Chemical Engineering,Anhui University of Technology;

    Zinc-ion hybrid capacitors(ZHCs) have attracted increasing attention due to their advantages such as low cost,improved safety and long-term cycling stability.However,despite these advantages,the development of ZHCs is still in its early stages and faces a number of challenges,such as the growth of electrode dendrites and the energy density is still unsatisfactory.Therefore,it is extremely crucial to develop reasonably matched electrode materials.Porous carbon materials have become one of the most potential cathode materials for ZHCs because of the advantages of low price,high porosity and stable performance.However,the low conductivity and inappropriate pore size distribution of traditional porous carbon materials limit their application in ZHCs.It is hoped that the problems can be tackled through the selection of raw materials and structure design.Herein,the hierarchical porous carbons(HPC/RHC_x) were prepared from rice husk and coal tar pitch using double template of KCl and MgO coupled with K_2CO_3 activation strategy.The HPC/RHC_6 features interconnected nanocapsule-like structure,large specific surface area(1 234 m~2/g) and hierarchical pore structure As the cathode material of ZHCs,HPC/RHC_6 exhibits excellent zinc storage performance.At the current density of 0.1 A/g,the specific capacity of HPC/RHC_6 reaches 125.3 mA·h/g,and at the power density of 115.4 W/kg,the energy density is 92.4 W·h/kg.After10 000 cycles of charge and discharge at a current density of 5 A/g,the capacity retention is 99.9%,showing excellent cycle stability.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1825K]

  • Preparation and sodium storage performance of hard-soft carbon composite materials

    XU Jiahao;ZHANG Zhaohua;LIU Yuhao;ZHAO Wei;LI Xiuchun;JIA Jianbo;HUANG Guangxu;XING Baolin;ZHANG Chuanxiang;Henan Key Laboratory of Coal Green Conversion,College of Chemistry and Chemical Engineering,Henan Polytechnic University;Henan Key Laboratory of Coal Green Conversion,Henan Polytechnic University;Henan Polytechnic University Ordos Research Institute of Clean Coal Development and Utilization;Hami Vocational and Technical College;China Coal Huali Xinjiang Carbon Technology Co.,Ltd.;State Col

    Sodium-ion batteries(SIBs) have attracted significant attention as energy storage devices,while the anode material,which represents a crucial component of SIBs,has emerged as a central point of investigation in related research. The low-ash coal tar pitch,a byproduct of the coal chemical industry,as a raw material for further research. The preparation of pitch based hard-soft carbon composite material was achieved by mixing the coal tar pitch directly with phenolic resin and subjecting it to a high-temperature carbonization process. The resulting materials were successfully applied to SIBs. The results of the SEM, TEM, XRD, Raman, XPS and FTIR tests demonstrate that phenolic resin have the ability to effectively inhibit the excessive graphitization of pitch during high temperatures.Furthermore,pitch can also repair irreversible defects created by phenolic resin during the carbonization process. Meanwhile,the crosslinking can occur between pitch and phenolic resin during the carbonization process. This phenomenon is conducive to the formation of pseudo-graphite structure in the composite materials,which results in the creation of additional adsorption and intercalation sites. As the mass ratio of pitch to phenolic resin increased gradually,the pseudo-graphitic structure content of the composites displayed an upward trajectory,followed by a decline. The composite material,comprising a mass ratio of 1∶4(LF-1∶4),exhibited the highest pseudographite structure content,at 32.88%. This was superior to the 21.28% observed in the material produced by direct heating of pure pitch(LQ) and the 27.08% observed in the material produced by direct carbonization of pure phenolic resin(FQ). The electrochemical tests,including constant-current charge/discharge and cyclic voltammetry,have demonstrated that the composite material of coal tar pitch and phenolic resin exhibited superior sodium storage performance. The hard-soft carbon composite material had an initial coulombic efficiency of 80.87% and a reversible capacity of 249.10 mAh/g with a pitch to phenolic resin ratio of 1∶4(LF-1∶4),which had a significant advantage over the material obtained by direct carbonization of pure coal tar pitch(LQ), which was 48.39% and 90.39 mAh/g,and pure phenolic resin(FQ) of 73.46% and 230.48 mAh/g. In contrast,the full cell prepared using LF-1∶4 displayed a reversible capacity of 251.37 mAh/g,with an energy density of 214 Wh/kg.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 2801K]

  • Supercapacitor performance of ammonia hydrothermal modified coal based porous carbon

    YUAN Chao;YE Yan;YANG Chunyan;TIAN Guoliang;LI Wanqing;QIN Zhihong;YANG Xiaoqin;Shanxi Provincial Key Laboratory of Intelligent Evaluation and Efficient Utilization of Coking Coal;Coking Coal Clean Utilization Laboratory,Shanxi Coking Coal Group Co.,Ltd.;School of Chemical Engineering and Technology,China University of Mining and Technology;

    Coal has unique advantages as a precursor for producing porous carbon electrode materials for supercapacitors due to its high carbon content,condensed aromatic structure,and significant economic benefits. By solvent extraction of coking coal from Shanxi,coal based heavy component(HC) was obtained as carbonaceous precursor,and KOH was used as an activator to prepare porous carbon materials(AHC). Then, ammonia water was used for hydrothermal modification at certain conditions to obtain a nitrogen-doped porous carbon with high rate performance and high cycling stability. The influence of different amounts of ammonia water addition on the microstructure, pore structure, surface chemical properties, and electrochemical performance of porous carbons was studied through characterization analyses such as SEM,FTIR,XPS,Raman,and N_2 adsorption. The results showed that the surface morphology and pore structure of the modified porous carbons were improved. When the ammonia addition was 8 mL,the resulting modified porous carbon AHC-N8 exhibited a distinct wormlike nano crack pore nitrogen content from 0.66%(without modification) to 2.83%. The porous carbon electrode material has a structure,with an increased proportion of mesopores and a surface specific capacitance of 351.3 F/g and a rate performance of 82% at a current density of 1 A/g,which is greatly improved compared to AHC(63.5%). After 10 000 cycles of charging and discharging at 10 A/g,the specific capacitance retention rate increased from 91.4% to 95.6%. The high specific surface area,suitable micro/mesoporous distribution,and high surface doping of pyridine nitrogen and pyrrole nitrogen contribute to the outstanding electrochemical performance of AHC-N8.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1799K]

  • Adsorption PErformance of Hg~0 by coal gasification slag: Reaction characteristics of sulfur-mercury on the surface of gasification slag

    YANG Xin;WANG Yahui;WANG Jiancheng;CHANG Liping;BAO Weiren;State Key Laboratory of Clean and Efficient Utilization of Coal-based Energy,Jointly Established by Province and Ministry,Taiyuan University of Technology;Key Laboratory of Coal Science and Technology,Ministry of Education,Taiyuan University of Technology;School of Environmental Engineering and Science,Taiyuan University of Technology,Key Laboratory of Atmospheric Pollutants Identification and Control in Shanxi Province;

    During the gasification process, sulfur and mercury in coal can migrateinto gas, wastewater, and gasification slag causing environmental pollution. Sulfur and mercury have strong affinities, and understanding the migration behavior of these elements during gasification is of great significance for proposing scientific control methods. In this study, the adsorption properties of Hg~0 on gasification slag under different working conditions are investigated by a fixed bed performance evaluation device, and the reaction characteristics of sulfur and mercury on the surface of gasification slag are revealed by N_2 adsorption-desorption, SEM, XPS, and other characterization methods. The results show that sulfur and mercury are mainly concentrated on the surface of fine slag, which has good Hg~0 adsorption performance, and physical adsorption plays a leading role. It is found that the higher the content of unburned carbon and minerals, the better the reactivity of sulfur and mercury on the surface of gasification slag. In addition, the atmosphere also affects the Hg~0 adsorption performance of the gasification slag. These findings provide a new idea for the high-value resource utilization of coal gasification slag, and also provide theoretical guidance and research basis for the collaborative removal of sulfur and mercury in syngas, thus contributing to the sustainable development of clean coal technology.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 2286K]

  • Thermal stress of solid oxide fuel cell stack via length to width ratio structural optimization

    XIONG Xingyu;MA Guiliang;WU Yunfei;WANG Xiaoai;LIANG Kao;PENG Suping;School of Mechanical and Electrical Engineering,China University of Mining and Technology-Beijing;Shanxi Research Institute of Huairou Laboratory;School of Energy,Power and Mechanical Engineering,North China Electric Power University;State Key Laboratory Coal Resources and Safe Mining,China University of Mining and Technology-Beijing;

    The Solid Oxide Fuel Cell(SOFC) is a highly efficient power generation device that directly converts the chemical energy in fuel into electrical energy through high-temperature electrochemical reactions, boasting exceptionally high theoretical conversion efficiency. However,its internal operating temperature is high(exceeding 700 ℃) and has a large temperature gradient,which results in significant thermal stress on various structural components during operation. This,in turn,causes deformation of the internal micro and macro structures,leading to a decline in electrochemical catalytic performance and,in severe cases,can result in damage to the fuel cell stack structure. Improving the thermal stress distribution within the stack can increase stack reliability, reduce the risk of structural damage,and extend the lifespan of the stack. A three-dimensional multi-physics coupled numerical model for a 5-layer planar fuel cell stack was established. While maintaining the same effective reaction area of the cathode,a series of thermal stress changes in the stack were analyzed when applying single cells with different length to width ratios. The results show that adjusting the length to width ratio of the single cells significantly affects the temperature distribution within the stack and the thermal stress distribution of each component.Increasing the length to width ratio of the single cells can improve the temperature distribution of the stack,effectively reduce thermal stress within the stack,and improve the stress distribution. When the length to width ratio is increased to 2.8∶1,compared to the most common 1∶1 square single cell,the highest temperature of the stack decreases from 1 128 K to 1 106 K,and the maximum temperature difference decreases from 107 K to 81 K. Besides the significant improvement in temperature distribution, the magnitude of stress distribution can be reduced by more than 40%. The maximum principal stress in the electrolyte decreases from 81.5 MPa to 46.8 MPa,and the maximum principal stress values in the anode,cathode,and sealant decrease from 46.3 MPa,31.3 MPa,and 21.1 MPa to 21.1 MPa,11.3 MPa,and 9.7 MPa,respectively. Therefore,reasonably increasing the length to width ratio of the single cells is an effective way to reduce thermal stress in the stack.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1890K]

  • Uncertainty analysis for prediction performance of solid oxide fuel cell(SOFC) anode model

    LIU Jiao;YANG Jianfei;CAI Liming;School of Automotive Studies,Tongji University;

    During the operation of solid oxide fuel cell(SOFC),complex physicochemical phenomenas such as convection,diffusion,surface reactions, and charge transfer reactions will occur. Coupling the reaction kinetics model with electrode simulation model can predict the performance of SOFC. Compared to the Butler-Volmer equation,the multi-step elementary reaction model can better describe the actual electrode kinetics. However,parameters of multi-step elementary reaction model usually contain significant uncertainties,which affects the accuracy of model predictions. To reduce model prediction uncertainty,an anode model for SOFC using humidified hydrogen gas(H_2/H_2O) as fuel is eatablished in this study,and polarization curve of the anode is calculated. Sensitivity analysis is conducted on the kinetic and thermodynamic parameters,with 11 sensitive parameters being identified. Forward and reverse uncertainty analysis are performed on the anode model separately,and the model prediction performance is optimized based on the results of uncertainty analysis.The results show that the optimized anode model reduces the prediction errors of the polarization curves at temperatures of 1 023.15 K and 1 123.15 K from original 33.12% and 34.51% to 8.61% and 15.47% respectively,the model prediction accuracy is improved.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 2031K]

  • Microstructure regulation of coal humate-based graphitized carbon and their lithium storage properties

    LI Jie;SUN Mingfu;YU Jitu;LI Long;MENG Weibo;LIANG Hao;XING Baolin;Shanxi Yongming Coal Mine Co.,Ltd.;Shandong Energy Group Northwest Mining Co.,Ltd.;State Key Laboratory of Coking Coal Resources Green Exploitation,China Pingmei Shenma Group;International Joint Laboratory of Coal Clean Utilization,Henan Polytechnic University;Henan Engineering Research Center of Coal-based Functional Carbon Materials;

    Phosphorus-doped coal-based carbon fibers were prepared by electrostatic spinning method using lignite,coal humic acid and coal pitch as raw materials,polyacrylonitrile as spinning aid and triphenylphosphine as dopant,focusing on the effect of phosphorus atomic doping on the microstructure and surface properties of coal-based carbon fibers. It was shown that phosphorus-doped coal-based carbon fibers with good flexibility could be successfully prepared from lignite,coal humic acid and coal pitch by electrostatic spinning method. The prepared phosphorus-doped coal pitch-based carbon fibers P-CTP-CFs were interwoven with each other to form a threedimensional mesh structure with an average diameter of 144.0 nm and a specific surface area of 50.3 m~2/g,and also contained a large amount of amorphous carbon and heteroatomic functional groups such as C—O,C=O,O—C=O,pyridinic nitrogen,pyrrolic nitrogen,graphitic nitrogen,and P—C/P—N,P—O,P=O. When used as self-supporting anode materials for lithium-ion batteries(LIBs),PCTP-CFs have excellent electrochemical properties,with a reversible capacity of 944.9 mAh/g at a current density of 20 mA/g,and a reversible capacity of 273.6 mAh/g at a high current density of 1 000 mA/g,and the reversible capacity can be maintained at 86.2% after100 cycles at a current density of 100 mA/g,showing good multiplicity performance and excellent cycling stability,which is a more ideal flexible anode material for LIBs. The excellent lithium storage properties of phosphorus-doped coal pitch-based carbon fibers are closely related to their special three-dimensional mesh structure,large specific surface area and abundant heteroatomic functional groups.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 3695K]

  • Progress in performance strengthening strategies of Ni-Co-Mn ternary cathode materials

    ZHENG Debing;DU Xianfeng;SONG Fangheng;Sichuan Contemporary Amperex Technology Co.,Ltd.;Yibin Guang Yuan Lithium Battery Material Co.,Ltd.;

    As a new type of green energy,lithium-ion battery has shown great potential to replace traditional petrochemical energy in many fields, and has made remarkable contributions to the practice of green sustainable development and the reduction of carbon emissions. As an important part of lithium-ion batteries,and their performance determines the future development space of lithium-ion batteries. At this stage, the cathode materials of lithium-ion batteries are relatively mature and stable, while the cathode materials of lithium-ion batteries are diverse,with many controllable factors and huge development space,which is the most critical unit for the rapid development of lithium-ion batteries. Nickel-cobalt-manganese ternary cathode material has the advantages of high energy density,environmental friendliness and reversible capacity,and is considered as one of the most potential cathode materials at present and in the future. In recent years,Ni-Co-Mn ternary cathode materials have shown strong commercial potential. At the same time,people have put forward higher requirements for Ni-Co-Mn ternary cathode materials. Due to the essential problem of poor cycle stability of cathode materials,there is a big difference between their actual performance and theoretical performance. Due to their rich controllability,there is a huge room for improving the performance of Ni-Co-Mn ternary cathode materials. In this work,the problems existing in Ni-Co-Mn ternary cathode materials were mainly discussed, including mixed discharge of Ni/Li, residual alkali on the surface, release of active oxygen, dissolution of transition metal ions and intergranular crack, and the effects and mechanisms of performance enhancement strategies such as element doping, surface coating and synergistic effect of element doping and surface coating on the properties of Ni-Co-Mn ternary cathode materials were expounded,so as to provide new research ideas for researchers in this field,stimulate more innovative ideas and promote the rapid development of Ni-Co-Mn ternary cathode materials.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1689K]

  • Recent progress about the development of iron-based catalysts for CO_2 hydrogenation to higher olefins

    HUANG Jie;AI Peipei;GUO Lisheng;SUN Song;School of Chemistry and Chemical Engineering,Anhui University;State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology;

    As global climate change intensifies,increasing attention has been directed towards the research of CO_2 emission reduction strategies and technologies for its resource utilization. High-carbon olefins,serving as crucial raw materials in chemical production,are predominantly synthesized from non-renewable petroleum resources through processes such as catalytic cracking. However, the production of high-carbon olefins from fossil resources is characterized by high energy consumption and reliance on non-renewable feedstocks. A promising catalytic pathway lies in the hydrogenation of CO_2 to produce high-carbon olefins using renewable green hydrogen as a reductant. Nevertheless,due to the stability of the CO_2 molecule,the activation of the C-O bond during hydrogenation and the subsequent coupling of C-C bonds pose significant challenges. This tandem reaction process inevitably encounters issues such as low activity,high selectivity for byproducts,and poor catalyst stability. Iron-based catalysts exhibit favorable activity in both the reverse watergas shift reaction(RWGS) and Fischer-Tropsch synthesis(FTS), combined with their low cost, ease of availability, and wide operating range, making them suitable for industrial applications. Modification of these catalysts can enhance their performance for specific reactions. Therefore,Fe-based or Fe-based composite catalysts can be utilized for the catalytic hydrogenation of CO_2 to high-value products,enabling the directed synthesis of high-carbon olefins from CO_2. This paper primarily focuses on the process route for producing high-carbon olefins via CO_2 hydrogenation, analyzing the research progress in Fe-based or composite catalysts from multiple perspectives, including element doping, support modulation, multi-active site construction, and process parameter optimization. It discusses the chain-growth mechanism of the catalysts and the primary factors influencing the selectivity of high-carbon olefins,providing insights for the development of efficient Fe-based catalysts. Additionally, the challenges and potential solutions facing the industrial application of CO_2 hydrogenation are prospected.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 2139K]

  • Reverse filtration combustion wave of coal and kinetic-transport regimes

    ZHANG Hao;SONG Zeyang;ZHAO Chongbao;HUI Shaotang;DANG Boyuan;College of Safety Science and Engineering,Xi'an University of Science and Technology;

    Coal reverse filtration combustion involves clean coal combustion, pollutant and disaster prevention and control. In-depth study of reverse filtration combustion wave model is of great significance for China to achieve carbon neutrality and sustainable development. In-depth study of the reverse filtration combustion wave model is of great significance for China to achieve the goal of carbon neutrality and sustainable development. However,there are still several key problems to be solved in this model: (1) The traditional oxygen component transport equation is difficult to solve the problem of oxygen non-equilibrium between gas and solid phases. (2) There is a lack of in-depth analysis of the dynamics and oxygen supply control mechanism of the reverse propagation dynamic process of filtration combustion wave. Based on this,a numerical model of reverse filtration combustion wave including five-step reaction system is constructed. At the same time,two different coal samples( bituminous coal CC and anthracite XA) were used to study the reverse filtration combustion under different flow conditions(8,32,64 L/min). The results show that: The model is in good agreement with the experiments,and it successfully predicts the propagation process of reverse filtration combustion wave. As the flow rate decreases,the reduction in oxygen supply leads to reduced reactivity,resulting in a decrease in both peak temperature and propagation rate. At the same time,the peak temperature is also affected by the type of coal sample. Under the same flow condition,the temperature of XA coal sample is lower than that of CC coal sample. As the reaction temperature increases,the reaction rate accelerates,and the limiting conditions of reverse filtration combustion from kinetic mechanism to oxygen transport mechanism.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1891K]

  • Study on re-emission and stabilization of mercury in seawater flue gas desulfurization wastewater

    ZHAO Hong;LEI Siyuan;LI Chengbao;TANG Ke;GUO Hao;WU Wei;MA Baolin;ZHENG Han;GUAN Jian;XU Renbo;LUO Tongda;SUN Lushi;Huaneng Dalian Power Plant;Suzhou Branch,Xi'an Thermal Power Research Institute Co.,Ltd.;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

    The seawater flue gas desulfurization(SFGD) system,as an ideal alternative to traditional limestone-based systems,effectively controls sulfur dioxide(SO_2) emissions from coal-fired flue gas while also suppressing mercury(Hg) emissions.However,the reductive nature of seawater has led to concerns regarding the re-emission of mercury on a global scale.In this study,the aeration process of SFGD wastewater was simulated to investigate the effects of pH,system temperature,and the concentrations of SO_3~(2-)and Cl~- on the re-emission of elemental mercury(Hg~0).The objective of this study was to elucidate the migration and transformation characteristics of mercury in SFGD systems.Furthermore,the study investigated the suppression mechanisms of four additives:two precipitants(Na_2S,an inorganic sulfide,and TMT-15,an organic sulfide) and two oxidants(NaClO and Fenton reagent).The results demonstrated that S(Ⅳ) was the primary factor promoting Hg0 re-emission,with over 54%of Hg~(2+)being reduced to Hg~0 at an SO_3~(2-)concentration of 0.05 mmol/L Concurrently,elevated concentrations of Cl~-,low temperatures,and heightened pH levels exhibited a substantial inhibitory effect on Hg~0 re-emission.All four additives effectively inhibited Hg~0 re-emission through different mechanisms.Na_2S and TMT-15 reacted with Hg~(2+)in the liquid phase to form water-insoluble precipitates and chelates,thereby preventing reduction to Hg~0.NaClO and Fenton reagent suppressed Hg~0 re-emission by rapidly oxidizing Hg~0 back to Hg~(2+)and stabilizing it in the liquid phase.They also inhibited Hg~(2+)reduction by oxidizing reductive ions in the solution.At optimal dosages,the suppression efficiencies of Na_2S,TMT-15,NaClO,and Fenton reagent were 78.1%,79.9%,84.8%,and 94.2%,respectively.Compared to precipitants,oxidants such as NaClO and Fenton reagent significantly reduced the required aeration intensity,demonstrating excellent potential for application in the aeration processes of SFGD wastewater treatment.

    2025 01 v.31;No.173 [Abstract][OnlineView][Download 1569K]
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