• Preparation and properties of monolithic macroporous SiO_2-based solid amine adsorbent for CO_2 capture

    YU Shunan;MA Kui;ZHOU Chang'an;SONG Lei;YUE Hairong;School of Chemical Engineering,Sichuan University;Institute of New Energy and Low-Carbon Technology,Sichuan University;

    Capturing CO_2 by adsorption method is an important technology to realize the separation and removal of CO_2 from industrial exhaust gas. Solid amine adsorbents have been widely explored due to its excellent adsorption capacity and selectivity of CO_2, and low energy consumption for desorption. In fact, traditional powder adsorbents can only be used after molding in actual industrial processes due to its large pressure drop and other problems. However, monolithic adsorbents still face challenges such as insufficient adsorption capacity and poor mechanical properties. Herein, using macroporous epoxy resin polymer as template and tetraethyl orthosilicate as silicon source, the monolithic macroporous SiO_2 was prepared by sacrificial template method. On this basis, the monolithic macroporous SiO_2-based solid amine adsorbent was obtained by impregnating different amount of tetraethylene pentaamine(TEPA). The monolithic macroporous SiO_2 material takes the cross-linked hollow SiO_2 microspheres as the skeleton, which has a typical macroporous structure, and TEPA is evenly distributed on the surface of the skeleton. Under 75 ℃ and 0.1 MPa(12% CO_2/88% N_2), the CO_2 adsorption capacity of 70 T-MS sample with 70% TEPA loading is up to 191 mg/g, which can be stably maintained above 160 mg/g even after 50 adsorption-desorption cycles. Dynamic adsorption results show that the CO_2 adsorption kinetics follow the Avrami model, indicating that the adsorption process is less affected by mass transfer diffusion limitations. Furthermore, the mechanical strength of the adsorbents can reach 0.72 MPa(axial) and 30.30 N/cm(radial), meeting the requirements of industrial adsorbents. Moreover, the adsorbents also exhibit excellent thermal stability and low heat capacity(2.79 J/(g·℃)), which is expected to achieve low-energy desorption and regeneration.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 26898K]

  • Review on integration of renewable energy and coal-fired power generation

    WANG Ruilin;SUN Jie;HONG Hui;School of Energy & Mechanical Engineering,Nanjing Normal University;School of Chemical Engineering and Technology,Xi′an Jiaotong University;Institute of Engineering Thermophysics,Chinese Academy of Sciences;

    In the context of carbon peaking and carbon neutrality, the integration of renewable energy and coal-fired power generation could improve the efficiency of renewable energy utilization, reduce the corresponding cost and also facilitate the green and low-carbon upgrading of coal-fired power generation. The integration and complementation of renewable energy and coal-fired power generation were reviewed from three aspects: integration form, operation regulation and the evaluation criteria. Firstly, the integration forms and working principles of solar thermal energy and biomass that can be directly coupled with coal-fired power generation were sorted out. Secondly, the current research on the dynamic characteristics and regulation laws of solar-thermal coupled coal-fired power generation were introduced. The improvement methods of slagging and corrosion in the operation of biomass coupled coal-fired power generation were summarized, the regulation strategies and optimal configuration of wind power and photovoltaic for coordinated operation with coal-fired power generation were outlined. Finally, the research progresses on the evaluation of the thermal performance, economy and comprehensive performance of the solar-coal complementary system were reviewed. The research progresses on the comprehensive performance evaluation of the coupled biomass and coal-fired power generation and the evaluation of the biomass power generation capacity in the system were introduced. The quantitative evaluation of the stability and flexibility of the coordinated operation of wind power, photovoltaic and coal-fired power generation and the construction of the comprehensive performance evaluation index system were outlined. Considering the current status of integration of renewable energy and coal-fired power generation, the integration of solar aided coal-fired power generation should be devoted to the study of deep peak regulation and more flexible system operation of the integrated system. Beyond the research on the mitigation of combustion problems brought by the coupling of biomass, the integration of biomass and coal power generation should focus on the evaluation of biomass power generation in the whole system. The coordinated operation of photovoltaic, wind power and coal-fired power generation should be further studied in addition to the scheduling planning, and the study of the internal responsibility sharing and benefit distribution mechanism of the wind and fire projects should be further carried out, so as to realize the synergistic and sustainable development among different types of power sources.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 3654K]

  • Life cycle assessment of power generation processes with mixed combustion of different sludge

    ZHOU Gang;SONG Tao;MA Shiwei;SHEN Laihong;GE Huijun;College of Energy and Mechanical Engineering,Nanjing Normal University;Key Laboratory of Energy Conversion and Control of Ministry of Education,School of Energy and Environment,Southeast University;

    In order to study the optimal treatment process of municipal sludge from the perspective of carbon, the environmental impact, resource consumption analysis and carbon emission accounting of the life process of municipal sludge and general solid waste, bituminous coal and rice straw mixed combustion power generation process through Life Cycle Assessment method were analyzed. The three sludge mixed combustion processes were divided into three stages: upstream production, production process and downstream production, and the weights of each environmental impact type were fully considered from the three perspectives of global, regional and local. The calculation results show that the total environmental impact values of the three mixed combustion processes are the largest under the global perspective, which are 0.87,0.12 and 0.09 person·a/t for every 1 t wet sludge treated(moisture content of 65%). Production upstream and production process(power generation stage) are the two main stages leading to environmental degradation. Global warming, acidification and solid waste are the three types of environmental impact that contribute greatly to the total environmental impact. The net carbon emissions of the three mixed combustion processes are 6 522, 742 and 410 kg CO_2,respectively.In terms of resource consumption, the resource consumption potential of sludge and general industrial solid waste mixed combustion power generation process is the largest, followed by sludge and bituminous coal mixed combustion power generation process, and sludge and rice straw mixed combustion power generation process is the smallest. On the whole, the sludge and rice straw mixed combustion power generation process is the most environmentally friendly and resource-saving sludge disposal process, which is worth vigorously promoting.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 25676K]

  • Performance analysis of coupling heating system for coal-fired power generation and waste-to-energy power generation

    DENG Genggeng;XUE Xiaojun;XU Gang;CHEN Heng;LIU Wenyi;Beijing Key Laboratory of Pollutant Monitoring and Control in Thermoelectric Production,North China Electric Power University;

    To actively respond to the dual carbon target and promote the development of renewable energy and coal complementary power generation technology, a coupled heating system of coal power generation and garbage power generation was proposed. Part of the heating exhaust steam of the coal-fired power unit is used to draw all the exhaust steam of the waste power unit through the extractor. After mixing, the water in the heat network is heated once. Through the spike heater, the heating extraction steam of the coal-fired unit is used to heat the heat network water again, so that it reaches the prescribed water supply temperature of the heat network. Through the system integration, the cold end loss of the heating extraction steam of the coal-fired unit and the waste generator unit can be effectively reduced, thus improving the overall efficiency of the system. A 660 MW coal-fired unit and a waste generating unit with a waste disposal capacity of 20.8 t/h were selected as the research objects, the simulation calculation was carried out through the EBSILON software and the detailed thermodynamic and economic analysis were carried out. The results show that when the electric power of the coal-fired unit is 495.00 MW(75% THA) and the garbage generator is 9.52 MW(100% THA), the exhaust steam loss of the garbage generator in the coupled system is reduced, the heating efficiency is increased by 0.16%, the power generation efficiency is increased by 0.52%, and the system coal consumption is reduced by 1.65 t/h(measured by standard coal). The energy-saving effect is significant. The exergy loss of the peak heater in the thermal grid is reduced by 6.06 MW and that of the waste generator is reduced by 2.04 MW. The reason for the efficiency improvement of the coupled heating system is the reduction of exergy loss of the heater in the thermal grid. After the heating renovation, the new equipment investment is 4.957 million yuan, the annual operation and maintenance cost is 198 300 yuan, and the system energy saving benefit is 5.429 2 million yuan. The final annualized new net income is 4.239 5 million yuan, which has a good economic benefit.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 14308K]

  • Integrated optimization and performance analysis of a novel hybrid system integrating plasma waste gasification with coal-fired power generation

    SUN Wen;Tongliao General Power Plant Co.,Ltd.;

    In order to realize efficient and clean resource utilization of medical waste, a power generation system coupling medical solid waste plasma gasification with coal-fired units was proposed. In the integrated system, medical waste is converted into high-quality synthetic gas in the plasma gasifier and directly sent to the coal-fired boiler for combustion after cooling. The heat released by the cooling of synthetic gas is used to heat the boiler feed water at the outlet of No.2 high-pressure heater in the thermal system of the coal-fired power plant, thus reducing the extraction of high-quality steam from the high-pressure cylinder of the turbine. In this paper, the plasma gasifier with a processing capacity of 6.72 t/h and a 660 MW coal-fired power generation unit were taken as research objects. Based on Aspen Plus platform, the original system and the integrated system were simulated, and the comparison before and after system integration was made through energy analysis, energy analysis and economic analysis. According to the first law of thermodynamics, after the system integration, the net power generation power is increased by 10.52 MW, and the net power generation efficiency at the garbage side has reached 36.21%. According to the second law of thermodynamics, before and after system integration, the increase of boiler loss is the largest, followed by condenser and turbine, and the total loss of gasification part is 5.11 MW. The total loss of the system is only increased by 0.27%, and the power generation efficiency at the garbage side of the system is 33.41%. According to the economic analysis results, the net present value of the medical solid waste treatment project within the life cycle can reach 457.646 6 million yuan, and the dynamic recovery period is 3.05 years. The integrated system has good thermodynamic and economic performance, which is expected to provide some guidance for engineering practice.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 17655K]

  • Review on solar aided coal-fired power generation

    HOU Hongjuan;ZHANG Nan;DING Zeyu;State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University;SPIC Power Plant Operation Technology Institute;State Grid Energy Research Institute Co.,Ltd.;

    Solar aided coal-fired power generation(SAPG) technology is a new complementary power generation technology, which not only can reduce CO_2 emissions of coal-fired power plant, but also decrease the cost of solar thermal power generation, and it has been widely concerned in recent years. Firstly, based on the working principle and operation characteristics of trough and tower solar fields, the different integration schemes of the SAPG system were summarized, the integration principles of the SAPG system with different coupling schemes were analyzed. Due to the high working temperature of the salt in the tower solar field, the integration apartment between coal-fired unit and solar field can be at the regenerative system or the boiler. For the trough solar field, the integration apartment is at the regenerative system due to the low temperature. Besides, the research status of SAPG system thermal performance was summarized. At present, the research of SAPG system thermal performance is mainly focused on static performance, few are related to the dynamic performance. The static performance analysis mainly includes the system photoelectric conversion efficiency, solar power generation power and other performance indicators under design conditions and variable conditions, as well as the impact of the thermal storage system on the operation of the SAPG system. The results show that the photoelectric conversion efficiency of SAPG system is higher than solar thermal power plant. In the research on dynamic performance, the variations operation parameters in SAPG system when the solar irradiation changes in a period of time was analyzed, and the stability and safety of the system were also discussed during the process. Based on it, the operation control strategy of SAPG system was formulated. After that, the economic performance of SAPG system was introduced.According to the calculation, the levelized cost of energy of SAPG system is about 0.66 yuan/kWh. For the calculation of solar energy contribution, four methods: heat proportional distribution method, extraction capacity method, thermal economic cost method and solar energy contribution analysis algorithm were analyzed. Among them, the energy grade and the unequal characteristics of solar thermal energy in the system are taken into account in thermal economic cost method and solar energy contribution analysis algorithm. At present, few real SAPG power station are built, and most of them are distributed abroad. There are only two practical projects in China, which are Datang Tianwei Jiayuguan 10 MW trough SAPG project and Shanxi Guojin SAPG project, with relatively few actual operation data and experience. At last, based on the research status of SAPG system, the possible development direction of the SAPG technology were presented in the future: that is, seeking the SAPG coupling scheme to enhance the deep peak shaving capacity of coal-fired units, and the development of the combined heat and power generation technology of the SAPG system will become the key research topic of the SAPG technology.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 10738K]

  • Design of solar-coal complementary power generation system based on magnesium-based flue gas carbon capture

    WANG Yuhao;ZHU Yanlin;LIU Wenzhuo;XING Chenjian;WANG Ruilin;ZHAO Chuanwen;School of Energy and Mechanical Engineering,Nanjing Normal University;

    The CO_2 emission from fossil-fuel power plants such as coal-fired power plants is huge, and carbon emission reduction from coal-fired power plants is the only way to achieve the dual-carbon goal. The alkali metal based solid absorbent for CO_2 capture has the advantages of low regeneration energy consumption and high selectivity. However, it is very costly to realize carbon capture by the power plant′s own energy, so it is proposed to use trough solar energy to drive magnesium-based carbon capture and regeneration to avoid the efficiency loss of carbon capture in coal-fired power generation, at the same time, the carbonation heat release is used to replace the steam extraction and heating water supply of the power plant, which increases the power generation. Based on the design and analysis of a typical coal-fired power plant development system, the additional power brought by the introduction of trough solar energy and carbon capture system into the design system was calculated, and the total output power of the design system, the single coal-fired carbon capture system and the reference system were compared. The results show that compared with the single coal-fired carbon capture system, the design system avoids 46.4 MW power loss, at the same time, the power generation is increased by 46.2 MW with the aid of heat release from carbonation. The power of the system is increased by 44 MW compared with the simple superposition system of single coal-fired carbon capture and single photothermal power generation, realizing the integration effect of 1+1>2. Taking into account the variation of the solar radiation intensity during a typical day, the system can be designed to avoid the influence of too high/too low radiation on the stability of the system by regulating the carbon capture process, the average carbon capture capacity and the additional power of the system can reach 135.6 t/h and 23.2 MW/h, respectively, realizing the efficient operation of the system under variable working conditions. The system is designed to avoid the loss of efficiency caused by the power plant′s own carbon capture, increase the amount of electricity generated, and achieve efficient use of solar energy and clean use of fossil fuels, which can provide ideas for the low-carbon and high-efficient utilization of the complementary renewable energy and fossil energy.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 11026K]

  • Theoretical study on evaluation of integrated solar combined cyclesystem based on energy level coupling

    SHI Yaolu;ZHANG Zhenwen;SUN Jie;WEI Jinjia;School of Chemical Engineering and Technology,Xi′an Jiaotong University;

    Integrated Solar Combined Cycle(ISCC) system is considered as a promising route to utilize both solar energy and fossil fuel. However, due to the absence of a unified framework and universal analysis of ISCC, it is difficult to achieve direct performance comparison between different integrated system schemes under the unified evaluation system. In the present work, a generalized model of ISCC system was proposed and established, which covered various integration schemes of solar energy taken into the Brayton and the Rankine cycles and the different integrated systems were reasonably summarized. Based on the model, the unified expression of fuel-savability was derived. The expression was verified and applied to evaluate the lateral performance of different integration schemes. Secondly, based on the idea of energy grade coupling, the "allocation effect" in ISCC system integration was revealed by using the bridge term in the unified expression, that is, the proportion of the total input(exergy) allocated to the Brayton cycle and Rankine cycle changes due to the different positions of solar energy input. Thirdly, based on previous work, the "superposition effect" was expanded that the total system fuel-savability was comprehensively determined by the superposed sum of the basic term, which was the direct benefit of local solar integration, the floating term, which stood for the explicit influence of solar integration on each main component, and the bridging term, which stood for the implicit inter-cycle influence of solar integration. This work provides theoretical guidance for the research and application of more generalized multi-cycle systems integrated with solar energy.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 7983K]

  • Energy-saving optimization study on 1 000 MW double reheat ultra-supercritical coal-fired power generation system integrated with solar energy

    WANG Jing;DUAN Liqiang;JIANG Yue;School of Energy Power and Mechanical Engineering,North China Electric Power University;

    In order to reduce the coal consumption and carbon emission of 600 ℃ double reheat ultra-supercritical(USC) coal-fired power generation system, an optimized system(scheme 2) for coupling tower solar energy to heat regenerative system feed water out of deaerator was proposed and compared on the basis of a 1 000 MW typical double reheat USC unit(scheme 1). The unit consumption analysis method based on exergy analysis is used to compare the thermal performance of different schemes of 1 000 MW level 600 ℃ double reheat unit and the energy consumption distribution of each scheme under variable working conditions was analyzed. The results show that the integration of solar energy heat into 600 ℃ double reheat USC coal-fired units can effectively reduce the coal consumption and carbon emission of unit. The standard power generation coal consumption rates of scheme 2 are lower than that of scheme 1 under variable conditions. Under 100% THA working condition, when 10%, 30%, 50%, 70% and 100% of the feeding water supply out of the deaerator are heated by solar energy, the standard power generation coal consumption rates of scheme 2 are reduced by 4.59,15.70,24.96,32.56 and 41.32 g/kWh, and the carbon emission are reduced by 12.70,43.50,69.10,90.28,114.50 g/kWh, respectively, so the effect of coal saving and carbon reduction is obvious. The unit consumption analysis method is used to study the additional unit consumption of each equipment unit of the unit. The additional unit consumptions of boiler, regenerative heater and condenser in scheme 2 are lower than that in scheme 1. The additional unit consumption of the boiler in scheme 2 is obviously reduced with the increase of the proportion of tower solarheating, while the additional unit consumption of tower solar energy is increased in scheme 2. Integration with solar energy can further improve the performance of coal-fired power plant.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 13228K]

  • Planning and design of thermal power and wind solar storage coupling

    CHENG Yu;SHAO Zhenzhou;ZHANG Jinbo;GAO Peixin;LIU Shuchang;WEI Zhongping;Huaneng Clean Energy Research Institute;Huaneng Renewables Co.,Ltd.;Huaneng Gansu Energy Development Co.,Ltd.;

    Combined with the advantages of the abundant coal storage, the stabilization of thermal power and the rapid development of clean energy, the construction of large-scale integrated energy bases is an important topic to adjust the energy structure and build the new energy system. Longdong district is suitable to construct the integration of wind, solar, thermal power and energy storage base because of its abundant storage of coal, oil, wind and solar resource. Based on the local energy resource and the geographical condition, a 10 GW integrated power system was designed, in which the planned capacities of wind power, photovoltaic and clean thermal power were 4.5 million, 1.5 million and 4 million kW respectively. To friendly connect to power grid, the integrated power system is configured with 30 MW/15 MWh energy storage for AGC frequency modulation and 150 MW/300 MWh energy storage for suppress the fluctuation of solar energy. Furthermore, in order to further analyze the rationality of the comprehensive energy base planning, the production simulation of the power generation system was carried out.The simulation indicates that peak load regulation by thermal power can reach the goal of high reliability, low dependence of power grid and high proportion of clean energy. The simulation also indicates that peak load regulation by thermal power and energy storage together can improve reliability of high DC and comprehensive utilization of power grid. Conclusively, the research of this paper achieves multi-energy complementary, uniformity dispatching, flexibly adjusting of power, coordinated development of power and grid.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 12443K]

  • Construction of typical zero carbon integrated energy system with deep coupling of coal and renewable energy

    LIN Guangping;LIU Zhaochuan;NIE Li;LI Weicheng;Dongfang Boiler Co.,Ltd.;Clean Combustion and Flue Gas Purification Key Laboratory of Sichuan Province;

    Coal is coupled with renewable energy and green hydrogen to build a coal-based zero-carbon/low-carbon integrated energy center, which can significantly improve the stability and flexibility of regulation of new power systems, significantly reduce the carbon emissions of power generation, and low-carbon alternative fuels are produced for deep decarbonization of downstream industrial sectors, or for cross-season storage. Based on this, typical systems such as IGCC(Integrated Gasification Combined Cycle) co-production of methanol coupled with photovoltaic hydrogen production, IGCC co-production of ammonia coupled with photovoltaic hydrogen production, oxygen-rich combustion coupled with photovoltaic hydrogen production, and CO_2 hydrogenation to methanol were constructed. The basic mass-energy balance matching of each unit, and the different daytime/nighttime operation modes adapted to the fluctuations of renewable energy with typical capacity were analyzed. The technical status of each unit were also analyzed and It was believed that these systems had the basic technical feasibility. The coupling system composed of IGCC with coal dosage of 2 000 t/d, 420 MW photovoltaic, 84 000 m~3/h hydrolytic hydrogen production and 2 500 t/d methanol synthesis can realize the on-grid load regulation from 0 to 557 MW and methanol production regulation from 750 to 2 500 t/d. The coupling system composed of IGCC with coal dosage of 2 000 t/d, 435 MW photovoltaic, 87 000 m~3/h water electrolysis for hydrogen production, and 2 000 t/d synthetic ammonia can realize the on-grid load regulation in 0-605 MW, and the production of synthetic ammonia regulation in 600-2 000 t/d. The coupling system consisting of 200 MWe coal oxygen-rich combustion power generation system, 80 000 m~3/h CO_2 capture, 3 600 MW photovoltaic, 720 000 m~3/h water electrolysis for hydrogen production, and 2 743 t/d methanol synthesis(CO_2 hydrogenation for methanol production) can achieve on-grid power regulation between 60 and 3 660 MW. The methanol yield is regulated from 823 to 2 743 t/d. In these systems, the process of coal conversion and utilization provides the basis for stable and reliable operation and flexible regulation of the system, which can greatly absorb the fluctuations of renewable energy. Coal and renewable energy are coupled to achieve the dual goals of low carbon and stability that are difficult to be achieved simultaneously when they operate separately. At the same time, the effective utilization of greenhydrogen by-product O_2 can effectively reduce the cost of traditional IGCC and oxygen-rich combustion. A coal-based zero-carbon/low-carbon integrated energy center combining coal, renewable energy and green hydrogen has a good development prospect in the future, and will play an important role in the realization of China′s carbon peak and carbon neutrality strategic goals. In order to promote the large-scale application of coal-based zero-carbon integrated energy center in the future, PEM water electrolysis hydrogen production technology adapted to the fluctuations of renewable energy, H_2 large-scale low-cost storage technology, CO_2 hydrogenation to methanol technology, gas turbine to fuel H_2 technology, etc. need to be further scaled up and greatly reduced in cost, so as to promote the large-scale application of coal based zero carbon comprehensive energy center in the future.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 23783K]

  • Thermodynamic study on the retention mechanism of alkali elements in biomass by kaolin addition under gasification condition

    HE Chong;BAI Jin;GUO Jing;LU Hao;HUANG Lei;College of Environmental Science and Engineering,Taiyuan University of Technology;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences;College of Safety and Emergency Management Engineering,Taiyuan University of Technology;

    Alkali metals(potassium and sodium) in biomass are easy to be released into the gas phase during gasification, causing corrosion, ash deposition, slagging and other problems in the gasifier, seriously affecting the long-term operation of the gasifier. In this study, the effect of kaolin addition on the release behavior of alkali elements during straw gasification was explored in the aspects of the distribution of alkali elements, phase evolution behavior, slag structure, and the Gibbs free energy of alkali element capture by slag, via thermodynamic modelling. The results indicate that K and Na are mainly in the form of the K-Mg silicate and feldspar, respectively, while sodium exists in feldspar, and the increase of temperature promotes the release of alkali metal in ash to gas phase. The released content of alkali elements increases with the gasification temperature. In addition, the mineral species and slag structure are the key factors governing the release behavior of alkali elements at low temperature and high temperature, respectively. The addition of kaolin at 800 ℃ promotes the transformation of potassium fixing minerals from potassium magnesium silicate to leucite in the ash, and the transformation of sodium fixing minerals from sodium calcium silicate to nepheline, reducing the release behavior of alkali metals. At high temperature, the addition of kaolin decreases the depolymerization parameter G value of slag, leading to the conversion of the structure unit Si-Si-O-O to Si-Al-O-O. The resulted Si-Al-O-O is the key structure unit of capturing alkali elements in the slag by forming the structure unit Si-KAl-O-O and Si-NaAl-O-O, and this process is driven by the charge compensation effect. Furthermore, the kaolin addition decreases the ΔG of the reaction of slag capture alkali elements at 1 400-1 600 ℃, which enhances the ability of alkali metal fixation of slag and inhibits the alkali element release. In contrast to Na, the ΔG of the K capture reaction by slag is higher, indicating that the K is easier to be released than Na during biomass gasification.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 30873K]

  • Simulation and validation of new type fixed bed gasification

    WANG Xueyun;ZANG Xuejing;DU Gang;GUO Liangyuan;China Coal Research Institute;Coal Science and Technology Research Institute Co.,Ltd.;State Key Laboratory of Efficient Mining and Clean Utilization of Coal Resources;

    In order to explore the operation conditions of the new fixed-bed gasifier, the numerical simulation combined with experimental data was carried out. In the experiment, low-rank coal was selected, the average particle size of coal was 10 mm, the coal dosage was 35 kg/h, the oxygen dosage was 10 m~3/h, and the operating pressure was set as 0.1 MPa to carry out the gasification test and get the data. Fluent dynamics numerical simulation and Aspen Plus thermodynamic numerical simulation were carried out respectively, which was compared with the actual test firing data. The results show that the absolute errors and the experimental values of the volume fractions of CO, H_2, CH_4 and CO_2 in the upper outlet simulated by Fluent are 0.027, 0.010, 0.020,-0.057, respectively. The absolute errors between the simulated volume fractions and the test values of CO, H_2, CH_4 and CO_2 at the lower outlet are-0.038, 0.007, 0.003 and 0.037, respectively. The absolute errors of the volume fractions and the experimental values of CO, H_2, CH_4 and CO_2 at the upper outlet simulated by Aspen Plus and the experimental values are 0.025,-0.028, 0.012 and-0.009, respectively. The absolute errors between the simulated and tested values of CO, H_2, CH_4 and CO_2 at the lower outlet are-0.022, 0.010, 0.002 and 0.010, respectively. Aspen Plus simulation results show that the absolute error of H_2 volume fraction in the upper outlet gas is-0.028, and the absolute error of other components is ≤0.025. Therefore, this model is selected to further study the influence of O_2 flow rate to coal mass flow ratio(O_2/coal) and H_2O to coal mass flow ratio(H_2O/coal) on gas composition. It is found that when O_2/coal is 0.328 and H_2O/coal is 0.405, the gas output in the upper and lower sections exhibits good characteristics, and the heating value is higher than 11 MJ/m~3, which can be used as the recommended operating parameters in the gasification process.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 15848K]

  • Interaction mechanism between gasification slag containing vanadium and corundum material

    MA Xiaotong;WANG Zhigang;PAN Yanhong;LIU Wei;ZHAO Jiangshan;WANG Yanxia;College of Chemistry and Chemical Engineering,Dezhou University;School of Chemistry and Chemical Engineering,Shandong University of Technology;

    High-sulfur petroleum coke is used for gasification, which can realize the efficient and clean utilization of petroleum coke. The entrained flow co-gasification of coal and petroleum coke is the common technical route of petroleum coke gasification. Compared with coal, the content of V element in petroleum is higher, which is easy to cause the corrosion of refractory materials. The refractory materials of chromium-free are developing at present, there is few researches on the erosion of slag containing V on new type refractory materials. A typical gasification coal ash was selected, which was mixed with V_2O_5 to simulate co-gasification ash of petroleum coke and coal. The corundum refractories with broad application prospects were used for corrosion test. The influences of V element content, reaction temperature and reaction time on the degree of erosion were investigated. XRD was used to analyze the evolution of minerals in slag containing vanadium at the high temperature process. The changes of morphology and surface during the corrosion process of V containing slag and corundum materials were analyzed by SEM. The erosion mechanism of slag containing V to corundum materials was clarified. The resultsshow that the V element in the slag forms vanadium aluminum spinel at the interface of corundum materials. The mutual substitution of V element and Al element in the slag forms an interactive reaction layer that erodes the surface of the material, which weakens the compactness of the corundum material surface. The penetration of the low viscosity liquid slag in corundum is intensified. With the reaction temperature increasing, the reaction between V element and Al_2O_3 of corundum is intensified, the size of crystalline spinel particles at the interface of corundum material increases, and the compactness of the reaction layer decreases, which accelerates the liquid slag with low viscosity penetrating into the corundum material, resulting in the erosion of corundum material aggravating. When the V content increases, the thickness of the reaction layer between the slag and corundum material increases, and the interaction interface becomes more irregular, resulting in a significant increase in the corrosion degree of corundum material. The penetration of liquid slag intensifies as the reaction time increases, This leads to the significant increase of the erosion degree of corundum material. The corrosion degree of corundum material also increases obviously with the reaction time increasing, as the penetration degree of liquid slag increases. V content is the most critical factor to determine the degree of corrosion. When the mass fraction of V_2O_5 in slag is 10%, and the reaction temperature is 200 ℃ higher than the flow temperature, the corundum material is most seriously eroded. When petroleum coke is gasified with coal, the V content and the operating temperature should be strictly controlled to avoid aggravating the erosion of refractory materials.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 56940K]

  • Preparation and desulfurization performance of activated coke based on phenolic plastic binder

    NIU Juntian;QIAO Xiaolei;YU Xinyue;YANG Li;LIU Haiyu;FAN Baoguo;JIN Yan;College of Electrical and Power Engineering,Taiyuan University of Technology;

    There is a lack of effective means to recycle waste thermosetting plastics at home and abroad, and most of them can only be landfilled or incinerated, which not only occupies a large amount of land resources, but also causes re-pollution due to a variety of harmful substances. If waste phenolic plastic is used as binder, the purpose of waste resource utilization can be achieved. At the same time, phenolic plastic is based on phenolic resin, which contains a large number of benzene rings in its structure and has a large cross-linking density, so it is feasible to use it as an active coke binder. In addition, phenolic plastic was prepared as binder and activated coke was made from lignite and charred coal, and the effects of phenolic plastic content and activation temperature on the performance of activated coke were explored by FTIR and N_2 adsorption/desorption. The results show that with the increase of the content of phenolic plastics, the strength of activated coke is enhanced, while both the basic functional group content and the specific surface area are decreased. When the content of phenolic plastics is 20%, pressure resistance strength and wear resistance strength of activated coke can meet the national high-grade standards. Meanwhile, the specific surface area of activated coke reaches to 262 m~2/g and sulfur capacity reaches to 9.88 mg/g, which is higher than that of industrial coke. With the increase of the activation temperature, the content of basic functional group and specific surface of activated coke area firstly increases and then decreases. When the activation temperature reaches to 800 ℃, the content of basic functional group and specific surface area reach to the maximum, the connection way between activated coke C—C and C with other atoms of surface has changed, aromatic ring is continuously compressed, side and branched chain is decreased, the activation effect is obvious. At this time, the sulfur capacity is the largest, and the desulfurization performance is the best.

    2022 11 v.28;No.147 [PaperDigest][OnlineView][HTML全文][Download 6801K]