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    Fundamental Research
  • Fundamental Research
    Numerical Analyses of Heterogeneous Reaction and Conjugate Transport Processes in Fixed-bed CLC with Columnar Oxygen Carriers of Various Diameter-to-Height Ratios
    HUO Guanping, GUO Xueyan
    2023, 43(6): 663-669. https://doi.org/10.19805/j.cnki.jcspe.2023.06.001
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    In order to understand how the shape of the columnar oxygen carrier affect the component diffusion and complex interstitial flow, and ultimately affect the overall gas-solid heterogeneous reaction performance, a computational fluid dynamics (CFD) method was applied to numerically analyze the fixed-bed chemical looping combustion (CLC) process with columnar oxygen carriers of various diameter-to-height ratios. Results show that the larger the diameter-to-height ratio of columnar oxygen carrier particles is, the higher the airflow mean velocity and pressure drop in the packed bed reactor are. Compared with conventional cylindrical particles, thin lamellar or rod-shaped particles have larger specific surface area and shorter diffusion distance, which can alleviate the intra-particle diffusion limitation in porous oxygen carriers and thus accelerate the overall gas-solid heterogeneous reaction rate and oxygen carrier conversion. In addition, for the same diameter-to-height ratio, the thin lamellar particles exhibit greater diffusion and convective mass transfer rates, leading to a greater conjugate mass transfer capacity.
    • Power Equipment and System
  • Power Equipment and System
    Modeling Method and Analysis of Bladed Disc in the Equivalent Blade Group Based on Jeffcott Theory
    ZHENG Qingshuai, GU Yujiong, LIU Yuhang, MA Jiwei
    2023, 43(6): 670-676. https://doi.org/10.19805/j.cnki.jcspe.2023.06.002
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    When modeling rotor system, it is difficult to analyze high order of matrix equation due to coupling relationship between blade and disc. Therefore, blades were usually treated as equivalent additional moment of inertia, and the blade and disc were treated as a whole rigid disc. However, this modeling method would split the energy coupling relationship between the long blade and the rotor in the case of high speed, resulting in a sharp increase of model error. When the coupling of blade and disc was considered, the circumferential blade set in the finite element model was equivalent to an orthoisotropic rigid ring by taking the first-order critical speed and modal approximation as equivalent criterion, and the relation between the radius of the disc after equi-calibration and the original disc was obtained through theoretical derivation and calculation. Finally, ANSYS simulation comparison was carried out. Results show that equivalent method can significantly reduce the degree of freedom of blade-disc model and ensure the reliability of the equivalent model.
  • Power Equipment and System
    Study on Layered Fouling Monitoring Method of Rotary Air Preheater
    GAO Rongze, WANG Limin, SUN Haojia, WANG Chao, WANG Yankai, LI Yingchun, CHE Defu
    2023, 43(6): 677-685. https://doi.org/10.19805/j.cnki.jcspe.2023.06.003
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    In order to facilitate the study on the effects of different structure parameters and working conditions on the fouling characteristics in multi-layer rotary air preheaters, and solve the difficult monitoring problem of layered fouling in preheater, a mathematical model for layered fouling monitoring of ash accumulation was established based on the finite difference method. Meanwhile, the rationality of the model was analyzed by a certain rotary air preheater with three sectors. Results show that as the measured temperature of each layer increases from 341 ℃, 241 ℃ and 104 ℃ to 367 ℃, 303 ℃ and 130 ℃, the clean factors decrease from 1 to 0.1, which indicates that the weakening of heat transfer is gradually aggravated. Accordingly, the deviation of the outlet temperature from the clean state increases from 0.8%, 2.6%, 2.8% to 7.8%, 26.1%, 25.2%. These data reflect that when fouling in a certain layer becomes more severe, the temperature difference between inlets and outlets decreases, indicating that the heat transfer capacity of the heat storage element is weakened. The proposed model has a great adaptability and can be applied to rotary air preheaters with any numbers of sectors and layers. A calculation can be completed within 2 s. If the data transmission delay of the power plant is ignored, the layered and real-time fouling monitoring of rotary air preheaters will be realized through the model.
  • Power Equipment and System
    Study on the Scheme of Reducing the Exhaust Temperature of a Lignite Boiler
    ZHAO Xingchun, WANG Jinjun
    2023, 43(6): 686-691. https://doi.org/10.19805/j.cnki.jcspe.2023.06.004
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    In order to solve the problem of high exhaust temperature of a lignite boiler, the integrated system of steam turbine and boiler was designed. Through optimizing the design scheme of boiler heating surface, a pre-economizer was arranged upstream of the economizer. The inlet of the shunt economizer was the low temperature and high pressure water supplied from the upstream of a high pressure heater, and the lower exhaust temperature could be obtained by adjusting the design of air preheater according to the corresponding change of heat balance. Finally, the boundary conditions of an Indonesian lignite unit were calculated. Results show that when the exhaust temperature decreases from 171 ℃ to 107.8 ℃, the boiler efficiency is increased by 3.96%, but the heat consumption is increased by 99.12 kJ/(kW·h). Comprehensive coal saving is the common problem of all lignite units at present. The solutions in this paper have good guidance and reference significance for similar projects.
  • Power Equipment and System
    Analysis on the Reasons for the Rising Flue Resistance of Gas Turbines in Long-term Shutdown
    TAO Zhentao, XU Maoxian, ZHANG Wei, LIANG Haining, ZHOU Yonggang, ZHAO Hong
    2023, 43(6): 692-699. https://doi.org/10.19805/j.cnki.jcspe.2023.06.005
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    According to the overall shutdown condition and operating load data of power plant units over the past three years,the relationship between flue resistance and unit load was analyzed. Based on the duration of shutdown, flue resistance before shutdown, average relative humidity and average temperature, multiple linear regression analysis was used to analyze main factors affecting the increase of flue resistance during unit shutdown. Results show that the number of shutdown days has a significant positive impact on the flue resistance, and there is a significant negative relationship between flue resistance before shutdown and the increase of flue resistance. Average relative humidity and average temperature show little positive impact on the increase of flue resistance. When the shutdown time reaches 30 days and the relative humidity reaches 49%, the flue resistance of the unit is likely to increase during the shutdown period.
    • New Energy Resources and Energy Storage
  • New Energy Resources and Energy Storage
    Research on Seismic Dynamics of Wind Turbines Based on the Effective Duration of Measured Earthquakes in China
    TANG Hongming, YAN Yangtian, MA Lu, LI Chun, NIU Kailun, LI Zhihao, XUE Shicheng
    2023, 43(6): 700-709. https://doi.org/10.19805/j.cnki.jcspe.2023.06.006
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    Based on the measured earthquakes in China, the structural response and local damage characteristics of a 10 MW single-pile onshore wind turbine under earthquake and turbulent wind loads were studied. The effective earthquake duration was calculated using Arias intensity, so as to conduct time-domain analysis of wind turbines, a multi-physical field model considering turbulent wind, earthquake and soil structure coupling effects was constructed by using the shell element refined finite element model, and the structural dynamic research was conducted on a 10 MW single-pile onshore wind turbine. Results show that turbulent wind load and seismic load are the determining factors affecting the forward and backward displacement and lateral displacement of the wind turbine tower top, respectively. Different seismic loads lead to seismic-induced structural buckling modes change.
  • New Energy Resources and Energy Storage
    Study on Dynamic Characteristics of Steam Generator in Solar Tower Power Generation System
    XU Ershu, HUANG Yuchen, KONG Yanqiang, DU Xiaoze, ZHANG Qiang
    2023, 43(6): 710-716. https://doi.org/10.19805/j.cnki.jcspe.2023.06.007
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    The steam generator in the Solar Two molten salt solar tower power plant was taken as the research object, the dynamic mathematical model of the steam generator was established based on the conservation equations of mass and energy. Based on the dynamic mathematical model, by analyzing the dynamic characteristics of the steam generator with disturbances at water side and molten salt side, the response curves of the outlet parameters and time constant of the steam generator were obtained. Results show that it takes 205 seconds for the steam generator to reach a new equilibrium after disturbance. However, due to the large heat capacity on the steam side, the response of parameters to disturbance is slow, and the quality of steam affects the safety and economy of the unit. Compared with molten salt, water and steam have higher specific volume and liquid storage capacity, the response speed of parameters at water side is much slower than that of molten salt side.
  • New Energy Resources and Energy Storage
    Study on Fluctuation Suppression Strategy of Solar Brayton Cycle with Storage Battery on Photovoltaic Output Power
    DAI Jiahao, XIAO Gang, ZHU Peiwang, YANG Jiamin
    2023, 43(6): 717-723. https://doi.org/10.19805/j.cnki.jcspe.2023.06.008
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    To study the fluctuation suppression strategy of concentrated solar power (CSP) in Brayton cycle with storage battery on photovoltaic (PV) output power, a PV-CSP with air Brayton cycle and battery combined power generation system was established. The PV worked as the main power generator, and the CSP and battery served as the supplementary power to stabilize the PV output power fluctuation. Four operation strategies were proposed for the efficient operation and load variation of the CSP micro gas turbine system. Results show that all the four strategies can reduce the PV output power fluctuation to some extents. Moreover, with the same battery capacity, strategy 2 causes the smallest PV output power fluctuation, while strategy 3 results in the lowest maximum battery charging power. As the battery capacity increases, the PV output power fluctuations of all strategies decrease, and the power fluctuation suppression abilities of strategy 2 and strategy 1 become closer to each other. When the ratio of heat and electricity storage is 3∶4, the output power fluctuations of the four strategies are reduced by 80.7%, 88.3%, 50.5% and 55.1%, respectively, compared to the PV-only case.
  • New Energy Resources and Energy Storage
    Study on SOFC/GT/ST/ORC System for Liquefaction and Recovery of CO2 by Coupling Ammonia Absorption Refrigeration
    TIAN Songfeng, LIU Shiyao, LIU YaXuan, BAO Zhongxiang, ZHANG Qian, LI Zhengkuan, ZHANG Du
    2023, 43(6): 724-734. https://doi.org/10.19805/j.cnki.jcspe.2023.06.009
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    In order to improve the efficiency of solid oxide fuel cell (SOFC) combined system and reduce carbon capture energy consumption, a combined system based on SOFC, gas turbine (GT), steam turbine (ST), organic rankine cycle (ORC) and ammonia absorption refrigeration cycle was proposed to liquefy and recover CO2. A SOFC ontology model was built and verified by Aspen Plus software. By inputting thermodynamic parameters under design condition, the effects of current density, fuel utilization rate and steam-carbon ratio on the performance of the SOFC and the combined system were studied. Results show that under design conditions, the electrical efficiency of the SOFC, the combined system and the power-cooling supply efficiency are 55.5%, 76.5% and 92.6%, respectively. Compared with the existing systems, each efficiency of the proposed system has been improved. When current density increases to the limit current density, the concentration polarization loss increases rapidly, which has a negative impact on system performance. With the improvement of fuel utilization rate, work-cooling ratio decreases, while each efficiency shows a trend of first increasing and then decreasing. When the steam-carbon ratio is 2, the electrical efficiency of the combined system and the power-cooling supply efficiency reach the highest, which are 78.04% and 93.2% respectively.
    • Digitalization and Intelligentization
  • Digitalization and Intelligentization
    Research on Optimal Control of SCR Denitrification System Based on Multi-model γ Incremental Stepped GPC
    ZHAO Zheng, MA Yijie
    2023, 43(6): 735-741. https://doi.org/10.19805/j.cnki.jcspe.2023.06.010
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    A multi-model γ incremental stepped generalized predictive cascade control strategy based on the feedforward of the inlet NOx predicted value was proposed. Firstly, the γ-SGPC-PID cascade controller under three typical working conditions was designed, then the global controller was constructed by fuzzy gain scheduling, and finally the feedforward-feedback SCR denitration control system was constructed by taking the predicted value of inlet NOx based on VMD-ARIMA as feedforward. Results show that the feedforward-feedback control system can adjust the ammonia mass flow rate accurately, reduce the fluctuation of NOx mass concentration at the outlet, and improve the quality of SCR denitration control system under variable working conditions.
  • Digitalization and Intelligentization
    Soft Sensing of Main Steam Flow of Steam Turbine Based on Data Driven
    XU Hongwei, LI Meishuang, LI Chongsheng, HE Yan, WU Zhiqun, HE Xin
    2023, 43(6): 742-748. https://doi.org/10.19805/j.cnki.jcspe.2023.06.011
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    In order to improve the calculation accuracy of the main steam flow, a prediction model was established while the main steam flow based on the heat balance and flow balance calculation under the steady-state condition of the steam-water system was taken as the target value, and the input parameters were limited to the range of high-pressure cylinder. With the characteristics of almost no hysteresis among parameters caused by the high flow rate of steam in the high-pressure cylinder, the model trained with the data under steady-state conditions could be directly applied to unsteady working conditions. Finally,the proposed method was virified by an example. Results show that the method has a wide range of working conditions and is less disturbed by other factors. The actual case verifies the accuracy of the model which has practical application value in engineering.
  • Digitalization and Intelligentization
    Fault Diagnosis Strategy for Rolling Bearing Based on Optimal Fusion of Variational Modal Decomposition and Deep Learning
    SUN Kang, JIN Jiangtao, LI Chun, XU Zifei
    2023, 43(6): 749-758. https://doi.org/10.19805/j.cnki.jcspe.2023.06.012
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    It is difficult to determine the fault type due to the strong nonlinearity characteristics of early vibration signal for the rolling bearing. Taking correlation kurtosis and Lyapunov index as comprehensive objective functions, the optimized variational mode decomposition (OVMD) parameter optimization method was proposed.The minimum value of comprehensive objective function was searched to determine the optimum combination of modal decomposition number and penalty factor. Noise reduction and feature extraction were realized to reconstruct the fault signal. The phase-space reconstruction method was adopted to restore the nonlinear structure of the system dynamics, and the pure signal was extracted by convolutional neural network (CNN).Results show that OVMD can effectively reduce noise and eliminate irrelevant components. After the reconstructed signal is learned by CNN, the attractor trajectories are shrunk, the signal nonlinearity is reduced, and the faults are separated. The OVMD-CNN diagnosis model has good robustness and generalization, which can realize the intelligent diagnosis of bearing faults.
  • Digitalization and Intelligentization
    Wind Turbine Gearbox Condition Monitoring Based on Improved Ensemble KNN Regression Algorithm
    ZHANG Shuyao, WANG Ziqi, LIU Changliang
    2023, 43(6): 759-767. https://doi.org/10.19805/j.cnki.jcspe.2023.06.013
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    Wind turbine gearbox is an important component that is prone to failure, and its maintenance cost is high, so it is necessary to monitor its real-time status. Aiming at the problem that the integrated K-nearest neighbor (KNN) algorithm was not sensitive to random sampling, an improved integrated KNN model based on regular sampling was proposed. Firstly, the distance correlation coefficient was used to select variables. Then the variables were sorted based on normalized mutual information and used for regular sampling to construct sub training sets. Finally, the threshold was set to analyze the real-time residual based on the statistical process control method, and the health of gearbox was monitored according to the health rate curve. This method was valified by the actual data of a wind turbine. Results show that the proposed method significantly improves the estimation accuracy of the model, which is better than the conventional ensemble KNN model, and can warn the early failure of the gearbox.
    • Green Energy and Low-carbon Technology
  • Green Energy and Low-carbon Technology
    Novel Waste-to-Electricity Coupling System of Anaerobic Fermentation and Incineration
    LI Juan, LI Jiarui, SUN Wen, CHEN Heng, XU Gang, ZHANG Guoqiang, LIU Tong
    2023, 43(6): 768-779. https://doi.org/10.19805/j.cnki.jcspe.2023.06.014
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    In order to improve economy of the waste-to-electricity system while comprehensively utilizing waste resources, two novel design schemes combining anaerobic fermentation and incineration were developed. Taking a waste incineration plant as research case, the fluid thermodynamic parameters and the power generation efficiency of coupling system utilizing anaerobic fermentation biogas were simulated by EBSILON. The economy of the proposed system was evaluated and the reasons for the improved energy utilization were analyzed by thermodynamic method. Result show that waste-to-electricity efficiency of the two schemes is raised by 6.59% and 14.89% respectively compared with the example system while the biogas-to-electricity efficiency can reach up to 31.82% and 45.66%, and the dynamic payback period is only 4.01 years and 2.77 years.
  • Green Energy and Low-carbon Technology
    Effect of Circulating Cooling Water Scale Inhibitor on Nucleation Process of Desulfurized Gypsum
    LIANG Luntao, XIAO Haiping, LEI Jing, HE Xiangyu
    2023, 43(6): 780-786. https://doi.org/10.19805/j.cnki.jcspe.2023.06.015
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    Under the background of zero discharge of wastewater in the whole plant, the scale inhibitors entering the desulfurization system with circulating sewage will prevent normal crystallization of gypsum. Gypsum crystallization experiments were performed with different scale inhibitors to explore the influence of scale inhibitor performance on nucleation characteristics of gypsum. Results show that scale inhibitor can prolong the induction time of gypsum crystallization and inhibit gypsum nucleation. The higher the mass concentration of scale inhibitor is, the more difficult the gypsum nucleation is. When the mass concentration of scale inhibitor is 10 mg/L, the induction time of gypsum crystallization increases by 17% to 48%, and the nucleation inhibition index ranges from 7% to 17%. The nucleation inhibition index of scale inhibitor F is minimum, and its nucleation inhibition effect is the weakest. After adding scale inhibitor D, the gypsum crystals appear as flakes, indicating that the complexation and dispersion performance of scale inhibitor D is strong, which seriously inhibited the gypsum nucleation. After adding scale inhibitor F, the gypsum crystals present as adhesive flakes and needle, indicating that the distortion performance of the scale inhibitor F is strong, and the nucleation is less affected. According to the morphology of gypsum samples with scale inhibitor added after crystallization, scale inhibitor F has the strongest distortion performance. Scale inhibitors with strong distortion performance have weak inhibitory effects on the gypsum nucleation process, and have a small nucleation inhibition index, which is more suitable for the requirement of the desulfurization safety operation.
  • Green Energy and Low-carbon Technology
    Techno-economic Analysis of Coal-fired Plant Integrated Carbon Capture and Storage Considering Carbon Trading and Carbon Tax
    ZHANG Caiqing, SHI Huiqing, ZHENG Nan
    2023, 43(6): 787-795. https://doi.org/10.19805/j.cnki.jcspe.2023.06.016
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    The economic analysis of a 1 000 MW ultra supercritical coal-fired plant integrated carbon capture and storage (CCS) system was carried out using economic cost analysis. And the evaluation criteria of power supply cost, net present value (NPV), dynamic payback period and internal rate of return were taken as evaluation indicators to investigate the impact of coal price, carbon trading price, carbon tax, inflation rate and CO2 price. Results show that the construction cost and energy consumption of plant integrated CCS system (PICCS) are relatively high, and the total investment and power consumption rate are 24.54% and 19.31% higher than that of the conventional unit. The power supply cost of the conventional unit is 0.307 5 yuan/(kW·h). The power supply cost of the PICCS is 35.87% higher than the conventional unit. The cost of CO2 emission reduction is 171.47 yuan/t. The net present value of PICCS is 13.806 billion yuan, which is 2.23 times than that of the conventional unit, meanwhile, the dynamic payback period of the PICCS is 4.15 years, which is 1.94 years earlier than that of the conventional unit. Considering carbon tax, carbon trading and CO2 sales simultaneously, the power supply cost of the PICCS is 0.196 4 yuan/(kW·h), which is 43.17% lower than that of the conventional unit. After the establishment of carbon trading, carbon tax policies and the CO2 recycling market, the PICCS is more profitability than the conventional unit.
    • Integrated Energy System
  • Integrated Energy System
    Multiple Energy Storage Optimal Configuration Method for Comprehensive Energy System Considering Wind/Photovoltaic Power Accommodation
    GAO Mingfei, ZHANG Ce, XIE Tong, LI Peng, HAN Zhonghe
    2023, 43(6): 796-804. https://doi.org/10.19805/j.cnki.jcspe.2023.06.017
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    Considering the influence of the renewable energy fluctuation on the stability of regional comprehensive energy system, the configuration and optimal operation method of multiple energy storage systems were proposed. Firstly, the day-ahead and day-in dual time-scale optimization model of regional comprehensive energy system was established based on the wind/photovoltaic power fluctuation. Day-in optimization model took day-ahead operation scheme as a reference, and revised day-ahead optimization results. Results show that the economic index of active energy storage operation strategy is better than passive energy storage for the regional comprehensive energy system with multiple energy storage configuration. The economic index of multiple energy storage configuration is better than single energy storage.
  • Integrated Energy System
    Exergy Cost Analysis Method for Heat and Power Cogeneration System Based on Reversible Work Ratio
    LIU Hao, WANG Zhen, CHEN Lian, WANG Nan, WANG Chenchen
    2023, 43(6): 805-814. https://doi.org/10.19805/j.cnki.jcspe.2023.06.018
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    To analyze the unit exergy cost of various output energies in cogeneration systems, an exergy cost analysis method based on reversible work ratio was proposed. The unit exergy costs of different forms of energy output by a thermodynamic system in a reversible process were equivalent, and were equivalent with the mean unit exergy cost of input energy. Exergy cost balance equations was established based on the hypothesis and reversible work ratio—the ratio of work to the total energy in a reversible process, and the unit exergy costs of output energies of a gas turbine heat and power cogeneration system was analyzed. The exergy cost of a natural gas distributed energy system was calculated.Results show that the exergy cost is higher when the energy quality is higher.