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    Fundamental Research
  • Fundamental Research
    Study on Sodium Removal and Combustion Characteristics of Zhundong Coal with Different Particle Sizes Washed by CO2 Enhanced Water
    YANG Tao, WEI Bo, MA Jinrong, CHENG Yanfeng, LI Xian, WANG Feng
    2022, 42(7): 589-594. https://doi.org/10.19805/j.cnki.jcspe.2022.07.001
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    In order to explore the change of sodium removal rate and combustion characteristics of Zhundong coal with different particle sizes after CO2 enhanced water washing, using a continuous water washing device and high-purity CO2 as acid source, three kinds of Zhundong coal samples with particle sizes of 0.5-1 mm, >1-3 mm and >3-5 mm were washed with CO2 enhanced water for 1 h and 6 h respectively. And the ash samples of the test samples were analyzed by X-ray fluorescence spectrometer. The sodium removal rates of Zhundong coal with different particle sizes after CO2 enhanced water washing was obtained, and its change law was obtained by using X-ray diffraction analysis. Subsequently, the combustion characteristics of coal samples with particle sizes of >3-5 mm and raw coal were studied by scanning electron microscope and thermogravimetric analyzer. Results show that with the longer CO2 enhanced water washing time and the smaller particle size, the sodium removal rate is higher. The ignition temperature and burnout temperature of coal samples after CO2 enhanced water washing are slightly lower than that of the raw coal, and the combustion characteristics are improved.
  • Fundamental Research
    Study on Elevated Temperature Tensile Properties of T91/TP347H Dissimilar Steel Welded Joints
    GAO Wei, JI Dongmei, PAN Weiguo, LIU Chuanhuai
    2022, 42(7): 595-603. https://doi.org/10.19805/j.cnki.jcspe.2022.07.002
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    High temperature tensile properties of welded joints and base metal of T91/TP347H dissimilar steel at different loading rates at 580℃ were studied, and an improved bilinear model was proposed. The position of dangerous point, displacement, stress and stress triaxiality of the sample during tensile process were investigated by means of finite element method. Results show that during the loading rate of 1.0×10-5-2.5×10-5s-1, it has little effect on the tensile mechanical behavior of the welded joints of T91 steel, TP347H steel and T91/TP347H dissimilar steel steel. The weak position of the welded joints of T91/TP347H dissimilar is at the weld of T91 side and located on the outer surface of the material. The T91 side has almost no radial deformation, while the TP347H side has radial deformation, which leads to reduction of the cross-sectional area of this side.
  • Fundamental Research
    Research on Prediction Method for Growth and Exfoliation of Steam Oxide of Heat-resistant Steels
    MA Yunhai, WANG Yanfeng
    2022, 42(7): 604-611. https://doi.org/10.19805/j.cnki.jcspe.2022.07.003
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    A prediction model of oxide layer growth based on Larson-Miller parameter method (LMP) and an oxide exfoliation model based on Armitt diagram were established,which provide reference for on-site application and life management of materials. Results show that the service temperature limit on the basis of the steam oxidation is about 680℃ for austenitic steels such as Sanicro25, shot-peened S30432, shot-peened TP347H, HR3C and SP2215, that of which is about 650℃ for S30432, TP347H and TP347HFG. For ferritic steels, the service temperature of T/P91 and T/P92 is limited to 600℃, and that of the steels VM12 and T122 are limited to 650℃ based on steam oxidation.
    • Power Equipment and System
  • Power Equipment and System
    Analysis of Nonlinear Characteristics and Thermal Deviation Control of Flow Gas in a Tower Boiler Furnace
    ZHAO Yanfeng, YANG Mo, WANG Wenshuai
    2022, 42(7): 612-621. https://doi.org/10.19805/j.cnki.jcspe.2022.07.004
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    To study the characteristics of the nonlinear flow gas in the furnace depended on the initial value, a simplified three-dimensional boiler model with completely symmetrical geometry and boundary conditions was abstracted from a tower tangentially fired boiler with symmetrical structure. Choosing three kinds of startup modes for simultaneous startup, diagonal startup and sequential startup, the influence of startup modes on the flow field, temperature field in the furnace and the thermal deviation at the furnace exit was numerically simulated. The velocity field, temperature field, uneven coefficient of velocity distribution and temperature deviation coefficient of each section were analyzed. Results show that compared with the traditional simultaneous startup mode, the control strategies of sequential startup and diagonal startup can improve the deviation of the gas flow field and temperature field in the furnace, and effectively reduce the thermal deviation at the furnace exit.
  • Power Equipment and System
    Research Progress on the Influence of Particle Fouling and Erosion Damage on the Performance of Axial Compressors
    CAI Liuxi, HE Yao, LI Yun, HOU Yanfang, WANG Shunsen, MAO Jingru
    2022, 42(7): 622-631. https://doi.org/10.19805/j.cnki.jcspe.2022.07.005
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    Aiming at the performance degradation and failure of compressors caused by particle fouling and erosion damage, the research progress of domestic and foreign research institutions in the influence of particle fouling and erosion damage on the performance of axial compressors in recent years was systematically summarized. Numerical simulation methods, experimental research methods and typical research conclusions about the compressor performance degradation mechanism and characteristics caused by fouling and erosion damage were emphatically introduced. Based on the current research hotspots and development tendency, further studies focus on the impact of particle fouling and erosion damage on the characteristic of axial compressors performance degradation were proposed. The interaction mechanism between the details of the unsteady flow field in the axial flow compressor cascades and the motion behavior of fine particles should be explored through refined numerical simulation and visualization experiment technology. Thus, the mechanism of compressor performance degradation caused by particle deposition and erosion damage could be revealed, and finally, quantitative relationship between particle deposition, erosion damage and compressor performance degradation should be established.
  • Power Equipment and System
    Energy Saving Optimization Study on Regenerative System of 700℃ Single Reheat Ultra-supercritical Unit with BEST
    WANG Jing, DUAN Liqiang, YANG Jinfu, YANG Ming, JING Yutian, TIAN Liguo
    2022, 42(7): 632-641. https://doi.org/10.19805/j.cnki.jcspe.2022.07.006
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    Aiming at the problems of high extraction superheat and large steam loss in the regenerative system of 700℃ single reheat ultra supercritical (USC) unit, two schemes were proposed and compared on the basis of the reference unit, while in scheme 1 the back pressure extraction steam turbine (BEST) was used to instead of stages 3-6 regenerative heater, and in scheme 2 both outer steam coolers (OSC) and BEST were used. The energy consumption distributions of different schemes under variable load were analyzed by using the unit consumption analysis method. Results show that both scheme 1 and scheme 2 can effectively reduce the superheat degrees of regenerative steam extractions and save more energy at higher load compared with the reference unit, but the reference unit has energy-saving advantages at lower load. So the BEST is suitable for higher load operation unit for 700℃ single reheat USC power generation system.
  • Power Equipment and System
    Study on Operation Optimization of Essential Service Water System in Nuclear Power Plant Under Low Seawater Temperature Condition
    XING Xiaofeng, ZHANG Zhenglou, LIU Linbao
    2022, 42(7): 642-646. https://doi.org/10.19805/j.cnki.jcspe.2022.07.007
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    In view of the situation that the water supply temperature of component water system (RRI) was lower than the operating limit when two essential service water pumps supplied by one intake channel or during switchover of two pumps, a mathematical model was established to analyse the relationship between seawater temperature and water supply temperature of RRI. And the optimization measures of operation regulation were recommended. Results show that the predictive results of the flow rate are consistent with experimental values, and can be used to predict the system performance. According to thermal hydraulic calculation, the system operation temperature can meet the criteria by backflow combination optimination measures. The combination group increases with the increase of the seawater temperature. System initial temperature can be maintained by increasing seawater temperature or reducing switchover time of two pumps. This mathematical simulation and hydraulic characteristic analysis also has certain reference for similar systems.
    • New Energy Resources and Energy Storage
  • New Energy Resources and Energy Storage
    Life Cycle Assessment of Coal-fired Solar-assisted Carbon Capture Power Generation System Integrated with ORC
    DONG Zhijian, YE Xuemin, SONG Ruizhe, LI Chunxi
    2022, 42(7): 647-656. https://doi.org/10.19805/j.cnki.jcspe.2022.07.008
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    Based on SimaPro software, the ReCiPe Midpoint (H) V1.13 method was used to conduct life cycle assessment of traditional coal-fired unit (scenario I) and coal-fired carbon capture power generation system integrating organic Rankine cycle (ORC) with solar energy (scenario II). The sensitivity of regeneration energy consumption and carbon capture rate of the carbon capture system to the environmental impact was analyzed. Results show that among the impact scores of all selected categories of the functional unit, the climate change potential (CCP) score is the highest, and the ozone depletion potential (ODP) score is the lowest. Except for CCP, other impact categories' scores are characterized with scenario II> scenario I. Regarding the human toxic potential (HTP) score, the contribution of the coal in the mining and transportation stages is the biggest, while in the other impact categories the most contribution is given in the system operation stage. As the carbon capture rate increases, the CCP per unit of electricity decreases, and the scores of other environmental indicators rise. With the increase of renewable energy consumption, the scores of all environmental impact categories of the integrated system rise.
    • Digitalization and Intelligentization
  • Digitalization and Intelligentization
    Research on Airfoil Optimization and Domain Adaptation Based on BP Neural Network Surrogate Model
    CHEN Chenming, GUO Xueyan, CHANG Linsen
    2022, 42(7): 657-663. https://doi.org/10.19805/j.cnki.jcspe.2022.07.009
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    The aerodynamic optimization of NACA64(3)-618 wind turbine airfoil was carried out by using the combination of neural network surrogate model and genetic algorithm. In the optimization for a certain working condition of wind field conditions in the Qinghai-Tibet Plateau, the parameter sample set was generated with Latin hypercube sampling, the airfoil was smoothed by B-spline curve, the lift coefficient and drag coefficient were predicted by surrogate model based on deep feedforward network, and the aerodynamic optimization selection was realized by combining with genetic algorithm. The optimization results were finally verified by using CFD simulation method. Results show that the lift drag ratio and lift coefficient of the optimized airfoil are increased by 4.52% and 4.05% respectively, and the drag coefficient is reduced by 0.42%. The optimization process can express a relatively complete airfoil with low dimensional parameters, and the surrogate model can get a better airfoil under severe conditions. The drag coefficient surrogate model has a higher accuracy and better performance in the field of domain adaptation, and is obviously better than the lift coefficient surrogate model.
    • Green Energy and Lowcarbon Technology
  • Green Energy and Lowcarbon Technology
    Prediction of SO2 Mass Concentration at Outlet of the Thermal Power Plant Based on mRMR and MA-RELM
    JIN Xiuzhang, LIU Yue, ZHAO Wenjie, YU Jing
    2022, 42(7): 664-670. https://doi.org/10.19805/j.cnki.jcspe.2022.07.010
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    A prediction model of outlet SO2 mass concentration based on max-relevance and min-redundancy (mRMR) algorithm and regularized extreme learning machine optimized by mayfly algorithm (MA-RELM) was proposed. The initial input variables were determined through mechanism analysis method, and the time delay of the initial input variables was compensated by improved time delay analysis method, the importance of each initial input variable was sorted by mRMR algorithm. Finally, the RELM prediction model was established, and the model parameters were determined by mayfly algorithm. Results show that compared with least square support vector machine (LSSVM), long short-term memory (LSTM) and extreme learning machine (ELM), root mean square error of the RELM prediction model is reduced by 36%, 38% and 26%, respectively. Compared with the model optimized by particle swarm optimization (PSO) and gray wolf algorithm (GWO), the error of the MA-RELM prediction model is the lowest, and the model can accurately predict outlet SO2 mass concentration.
  • Green Energy and Lowcarbon Technology
    Synergistic Control Characteristics of Volatile Organic Compounds and Conventional Pollutants by Air Pollution Control Devices
    XIANG Jiatao, LI Junting, ZHOU Xiaoming, LIAO Xinjie, LIAO Wei, REN Shaohui, ZHANG Xiong, ZHANG Shihong
    2022, 42(7): 671-676. https://doi.org/10.19805/j.cnki.jcspe.2022.07.011
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    The coal-fired flue gas from each measuring point at the tail of the fluidized bed incinerator in laboratory was collected by gas bags and absorption tubes, so as to study synergistic control characteristics of volatile organic compounds (VOCs) and conventional pollutants in flue gas by air pollution control devices (APCDs). Results show that the mass concentration of benzene in VOCs is the highest, followed by styrene. While APCDs can effectively remove conventional pollutants, the total removal efficiency of 15 kinds of VOCs can reach 92.58%. The synergistic control effect between the following VOCs and conventional pollutants is the best, such as n-heptane, toluene, cyclopentanone, styrene and anisole, followed by benzene and o-xylene, while there is no synergistic control effect between n-hexane, isopropanol and conventional pollutants.
    • Integrated Energy System
  • Integrated Energy System
    Thermodynamic Performance Analysis of Cogeneration System for Coupling of Geothermal and Biomass-fired Plant
    WANG Yihan, WANG Huating, LU Di, CHEN Heng, XU Gang, LEI Jing, LIU Tong
    2022, 42(7): 677-685. https://doi.org/10.19805/j.cnki.jcspe.2022.07.012
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    A new coupling system integrating geothermal water under different temperatures with biomass cogeneration units was proposed, in which, geothermal energy was integrated into steam-water cycle of the biomass cogeneration unit to replace part of extraction steam of steam turbine. Based on a 35 MW biomass cogeneration unit, thermodynamic performance of the new coupling system was evaluated. Results show that for the new coupling system with geothermal water temperature of 110℃, the extracted geothermal water is in a state of relatively high temperature, which can be used as the heat source to drive the heat pump and save extraction steam. The increase of generation power of the new coupling system can be divided into three parts, including the transformation of the unit, the newly set extractor and geothermal auxiliary. Total exergy efficiency of the new coupling system can be greatly improved under different geothermal water temperatures. The new coupling system shows significant economic advantages.
  • Integrated Energy System
    Effect of Pinch Point Temperature Differences on Performance and Economy of Supercritical CO2 Recompression Brayton Cycle
    Lü Yongxing, YAN Chenshuai
    2022, 42(7): 686-692. https://doi.org/10.19805/j.cnki.jcspe.2022.07.013
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    Taking the supercritical CO2 recompression Brayton cycle power generation system as the object, the effect of pinch point temperature differences of low temperature recuperator (ΔTp,LTR) and high temperature recuperator (ΔTp,HTR) on performance and economy of the cycle system was analyzed. Based on the thermal power distribution and exergy loss distribution of various components of the cycle system, the causes for the impact of pinch point temperature differences on cycle performance and economy were studied. Results show that compared with the change of ΔTp,HTR, cycle thermal efficiency and exergy efficiency are more sensitive to the change of ΔTp,LTR. The sensitivities of total heat exchange area of the recuperator and cycle performance to ΔTp,LTR and ΔTp,HTR are similar. There always exists an optimal match between ΔTp,LTR and ΔTp,HTR under the specified cycle thermal efficiency, so that the total heat exchange area of the recuperator reaches the minimum.