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    Fundamental Research
  • Fundamental Research
    Study on Effect of Structure Design of Oxygen Carriers in Chemical Looping Combustion on Abrasion Resistance
    ZHAO Yifan, LIU Dunyu, JIN Jing
    2024, 44(4): 509-519. https://doi.org/10.19805/j.cnki.jcspe.2024.230134
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    During chemical looping combustion, oxygen carrier plays a crucial role as the carriers of oxygen and heat. Design of oxygen carrier has always been the emphasis and difficulty in chemical looping technology research. Chemical looping combustion usually occurs in a fluidized bed reactor. Since the chemical stress caused by chemical reactions has the greatest contribution rate to the abrasion of oxygen carrier, the life of oxygen carrier is significantly shortened and the effective components run away. From the perspective of oxygen carrier structure design, the anti-abrasion mechanism of different composite oxygen carriers was qualitatively evaluated. The core-shell structure inhibits the phase separation of the active components and avoids the deactivation of oxygen carrier caused by surface abrasion of the active components. The addition of Al2O3 fiber and "rivet" inhibits crack growth and slows down the abrasion of the material. The addition of fuel ash improves the skeleton strength of the composite oxygen carriers, and the resistance to abrasion and slagging aggregation of oxygen carriers. The synergistic effect of the composite oxygen carrier increases the reactivity and slows down the sintering agglomeration phenomenon. From the perspective of abrasion dynamics and service life, the abrasion conditions of different oxygen carriers were quantitatively compared. By logarithmically fitting of the Gwyn abrasion dynamics equation, fitting parameters K and n of different oxygen carriers were calculated, which reflects the abrasion mechanism and abrasion patterns.
  • Fundamental Research
    Mechanism Optimization for Methane Oxygen-enriched Combustion Based on Artificial Neural Network
    HUANG Zhangjun, XU Tong, HE Honghao, SUN Liutao, TIAN Hong, LI Xinzhuo
    2024, 44(4): 520-527. https://doi.org/10.19805/j.cnki.jcspe.2024.230115
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    In order to optimize the ignition delay time and CO mole fraction, a new optimization mechanism for methane oxygen-enriched combustion based on artificial-neural-network (ANN-OMOC) was proposed by simplification and optimization for the detailed methane oxygen-enriched combustion mechanism USC mech2.0, using the directed relational graph with error propagation, full species sensitivity analysis and artificial neural network (ANN). The results of simulation calculation and comparative analysis for methane oxygen-enriched combustion show that the prediction errors of ignition delay time and laminar flame velocity are reduced from 2.53%, 24.38% to 0.50%, 14.41% by use of ANN-OMOC, compared with the prediction error of the simplified mechanism FSSA for methane oxygen-enriched combustion. Meanwhile, compared with the simplified mechanisms DRGEP and FSSA for methane oxygen-enriched combustion, the optimized mechanism ANN-OMOC has the best prediction results for ignition delay time, peak mole fraction of OH and peak mole fraction of CO, with relative errors of less than 10%.
  • Fundamental Research
    Study on Corrosion Behavior of Ni-base Alloys 263, 282 in Flue Gas Above 700 ℃ from Coal-fired Boiler
    PAN Peiyuan, WANG Yuzhou, WU Xianglong, ZHANG Naiqiang
    2024, 44(4): 528-536. https://doi.org/10.19805/j.cnki.jcspe.2024.230100
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    The corrosion behavior of commercial Ni-base alloy materials 263 and 282 in a simulated environment of flue gas at 700-800 ℃ from coal-fired boiler was studied. The weight change of Ni-base alloys after corrosion was calculated, and a scanning electron microscope-energy dispersive spectroscope (SEM-EDS) was used to analyze the microtopography of the corroded alloys. Results show that the corrosion behavior of Ni-base alloys includes three mechanisms: oxidation, sulfidation, and sulfate corrosion. The corrosion rate is controlled mainly by sulfate corrosion. The molten sulfate eutectics lead to general corrosion of the Ni-base alloys, thus the alloy matrix is dissolved continuously at an approximately constant rate, and the weight loss of the alloy increases first and then decreases with the increase of temperature. Meanwhile, sulfur diffuses into the alloy matrix and results in local sulfidation. The low-melting metal sulfides melt down which might lead to formation and propagation of internal cracks in the alloy. The increase of temperature will significantly aggravate the sulfidation corrosion of Ni-base alloy.
    • Power Equipment and System
  • Power Equipment and System
    Cost Benefit Analysis for Strategic Reserve Generation Units
    LI Zheng, DU Binglin, ZHANG Ruiyu, LI Chenpeng, LIU Pei, LIU Jianmin, XIE Yucai
    2024, 44(4): 537-546. https://doi.org/10.19805/j.cnki.jcspe.2024.230210
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    Extreme weather events become more frequent because of climate change, posing a threat to the security and stability of the electricity system. Current researches about strategic reserve generation units mainly focus on policy evaluations or modelling simulations from the perspective of unit costs and power sale income, which do not adequately account for the economic and social effects they can bring. In order to comprehensively analyze the economics of strategic reserve generation units, a cost-benefit analysis model was established from the perspective of the whole society, considering the benefits including the guarantees for the economic production, health benefits for residents and labor force level, and the costs of strategic reserve generation unit investment and operation, and Sichuan power restriction event was taken as a case study for analysis. Results show that the benefit for 1 kW·h electricity that can be brought by the strategic reserve generation units is 4.77 yuan/(kW·h) and the required costs for 1 kW·h electricity generated by building new strategic backup units and using units that are close to retirement were about 1.91 yuan/(kW·h) and 0.47 yuan/(kW·h), respectively. Thus it is economically feasible to build and operate the strategic reserve generation units from the whole society perspective. At the same time, the operating hours are the most critical factor affecting the cost of strategic reserve generation units, and if the operating hours are less than 89 hours in a year, the unit's cost of electricity will be higher than its social benefits.
  • Power Equipment and System
    Analysis of Levelized Cost of Energy and Cost of Electricity Supply for 660 MW Coal-fired Power Station Under CCUS Application
    ZHAO Shuyuan, YUAN Xin, LIU Jun, CHEN Heng, WANG Xiuyan
    2024, 44(4): 547-556. https://doi.org/10.19805/j.cnki.jcspe.2024.230165
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    In order to study the changes in levelized cost of energy and cost of electricity supply after the carbon capture, utilization and storage (CCUS) retrofit of a coal-fired power station, the current development trend of the electricity-carbon market was summarized and analyzed, and a simulation model was built to show the cost and benefit of CCUS application for 660 MW coal-fired power station. A sensitivity analysis was carried out using the cost of carbon capture cost and carbon trading price as variables. Results show that the predicted levelized cost of energy of the thermal power units after CCUS retrofit will fall to the range of 20% upward fluctuation of the regional coal trading benchmark price between 2034 and 2035. After 2039, the change rate of levelized cost of energy before and after the transformation will be negative, which means that the levelized cost of energy after transformation will be lower than the target of levelized cost of energy before transformation. In addition, although the carbon capture cost and carbon trading price will have more or less impacts on levelized cost of energy and power supply cost, the coupling effect of carbon capture cost and carbon trading price still has good economic results in the future for the CCUS retrofit projects of the thermal power units.
  • Power Equipment and System
    Three-dimensional Temperature Field Reconstruction Based on Tucker Decomposition and Acoustic Thermometry
    YAO Pengbo, SUN Mingyang, WANG Yuan, SHEN Guoqing
    2024, 44(4): 557-565. https://doi.org/10.19805/j.cnki.jcspe.2024.230250
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    A three-dimensional temperature distribution reconstruction algorithm based on Tucker decomposition and acoustic temperature measurement was proposed. In the algorithm, numerical computation was used to establish a priori dataset, the main characteristics of the boiler temperature field were extracted using Tucker decomposition, and acoustic temperature measurement was combined with two-dimensional temperature field interpolation to reconstruct the three-dimensional temperature field. The algorithm could improve the reconstruction accuracy of complex temperature fields and have a fast reconstruction speed. Results show that the method can reconstruct complex three-dimensional temperature fields in about 10 seconds, and reduce reconstruction errors by more than 10% compared to traditional acoustic temperature measurement. It also has strong applicability for temperature fields outside priori operating conditions, and has some guiding significance for combustion optimization and load adjustment in coal-fired power plants.
    • New Energy Resources and Energy Storage
  • New Energy Resources and Energy Storage
    Cooperative and Optimal Scheduling of Wind Turbine Groups Based on Active Wake Control
    HU Yang, ZHANG Chong, FANG Fang, LIU Jizhen
    2024, 44(4): 566-574. https://doi.org/10.19805/j.cnki.jcspe.2024.230140
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    Aiming at the serious impact of wake effects between wind turbines on the power generation efficiency of wind turbines, a calculation method for safe yaw constraints of wind turbines, a mixed semi mechanism modeling method for wake characteristics, and a multi-objective collaborative optimization scheduling method for wind turbine groups were proposed. Based on the FAST.FARM platform, the dynamic interaction and integration simulation environment between multi degree of freedom controllable units and wake was improved, and compared and analyzed the collaborative operation optimization performance of two units arranged in tandem and seven units arranged in an offshore wind farm in East China. Results show that the established integrated simulation model can reasonably characterize the multi domain dynamic interaction characteristics between wind turbine groups and air flow fields. The proposed method can effectively improve the power generation efficiency of wind turbine groups and promote balanced optimization of economic benefits, resource utilization and cost control.
  • New Energy Resources and Energy Storage
    Sensitivity Analysis of Field-yaw-based Control of Wake for the Wind Farm
    TANG Jing, ZHAO Ying
    2024, 44(4): 575-581. https://doi.org/10.19805/j.cnki.jcspe.2024.230174
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    Deflected yaw control is beneficial to reduce the wake effect of wind turbines, and the power generation of wind farm can be maximized by reducing wake loss through yaw optimization at field-level. The FLORIS wake surrogate model was used to optimize the yaw angles of all turbines to reach the maximum total power of wind farm. The sensitivity of yaw optimization to wake loss and power increase was compared and analyzed in terms of different spacing distance of turbines, number of turbines, turbulence intensity, incoming wind speed and wind direction. Results show that yaw control of wind farm has the best effect on wake optimization when the turbine distance is less than 5D, there are more than 3 turbines at line, and only the first 5 rows need to be optimized, the angle between turbine-connect-line direction and main-frequency wind direction is less than 15°, the wind turbulence is less than 0.1 and wind speed is within the range of "cut-in+2 m/s" and "rated+2 m/s". If only single-turbine yaw control system is used, the yaw error of 3°~5° is beneficial to the overall wind farm power generation.
  • New Energy Resources and Energy Storage
    Design and Experimental Research of an Ocean Thermal Energy Experimental Plant
    LIU Xinyu, ZHANG Li, WU Pengfei, ZHU Jianhua
    2024, 44(4): 582-589. https://doi.org/10.19805/j.cnki.jcspe.2024.230160
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    In order to verify the feasibility of ocean thermal energy conversion and test the working performance of the key equipments, test the performance of key equipment and provide reliable data support, a 50 kW ocean thermal energy power generation test platform was designed and constructed. A mathematical model of the organic Rankine cycle system was established to study the effect of temperature of cold and warm seawater on system performance. The accuracy of the theoretical design model was verified and the operating characteristics of the plant under design condition were tested. Results show that larger temperature difference enables higher thermal efficiency. The experimental results agree well with the simulation data, and the maximum power output of the system can reach 43.9 kW, with an average thermal cycle efficiency of 2.49%.
  • New Energy Resources and Energy Storage
    Battery Storage Energy Assistance Auxiliary Secondary Frequency Regulating Control Strategy Based on Adaptive Decomposition of Frequency Regulation Signals
    LIU Xinping, LIU Lei
    2024, 44(4): 590-598. https://doi.org/10.19805/j.cnki.jcspe.2024.230108
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    When zero-carbon units represented by clean energy power generation were integrated into the grid on a large scale, frequency fluctuations caused by intermittency and uncertainty became more prominent. Aiming at the problems of insufficient flexibility in frequency modulation and unsatisfactory effect in charge state maintenance of thermal power units assisted by battery energy storage, an energy storage assisted secondary frequency modulation control strategy based on adaptive decomposition of frequency modulation signals was proposed. Firstly, the switching time criterion of regional adjustment demand signal and regional control error signal was given by synthesizing sensitivity, energy storage charge state and frequency deviation state. Considering the climb rate limit of thermal power units and the state limit of stored energy, an adaptive frequency modulation signal decomposition strategy was proposed, and the rule between return gain and state of charge was constructed as the adjustment reference value. Frequency deviation was used to correct the reference value. Finally, the state consistency detection module was used to judge the output of return gain, so as to realize the complementary advantages of the two frequency modulation resources. Effectiveness of the proposed strategy was verified by the simulation of the single-region system frequency response model. Results show that the strategy can improve the flexibility of the system and make each frequency modulation resource form a complementary relationship.
    • Digitalization and Intelligentization
  • Digitalization and Intelligentization
    Improved Linear Active Disturbance Rejection Control and Parameter Tuning Method for High-order Plus Time-delay Systems
    LIU Changliang, YANG Chaojie, LIU Weiliang, LIU Shuai, WANG Ziqi
    2024, 44(4): 599-606. https://doi.org/10.19805/j.cnki.jcspe.2024.230173
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    Aiming at the problems of poor adjustment effect and difficult parameter setting of traditional linear active disturbance rejection control (LADRC) for high-order plus time delay (HOPTD) systems, a high-order time delay-linear active disturbance rejection control (HTD-LADRC) was proposed. On the basis of first-order LADRC, a high-order feedforward compensator was connected in series to solve the problem of asynchronicity between feedforward signal and feedback signal of the linear extended state observer (LESO) and the accuracy of state observation of the system was improved. On this basis, the objective approximation legal quantization parameter setting formula was used, and the adjustable interval of parameters was derived to realize single parameter λ adjustment of controller parameters and simplify parameter setting. Furthermore, the frequency domain analysis method was used to verify the effectiveness of the tuning method, and the relationship between the parameters and the system robustness was determined. Finally, in the simulation experiment of selective catalytic reduction (SCR) denitration control system, the proposed controller was compared with other controllers to verify its superiority. Results show that the proposed high-order linear active disturbance rejection control with time delay has obvious advantages in fixed value following, disturbance resistance and robustness, and has great engineering application potential.
  • Digitalization and Intelligentization
    Research on Torque-Pitch Coordinated Control of Floating Offshore Wind Turbines Based on Improved Model-free Adaptive Control
    ZHANG Yanfeng, YANG Xiyun, WANG Xinzhe
    2024, 44(4): 607-615. https://doi.org/10.19805/j.cnki.jcspe.2024.230185
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    A coordinated torque-pitch control strategy based on improved model free adaptive control was proposed to overcome the difficulties in modeling floating offshore wind turbines and the serious fatigue damage caused by frequent pitch action. This strategy didn't rely on the mathematical model of the floating offshore wind turbine. The model free adaptive control method was improved by integrating the iterative learning control strategy; a multi input and multi output controller with the generator torque and pitch angle as control variables was designed for coordinated control; allow the wind turbine to be used as kinetic energy buffer under the non-zero pitch angle, and the amount of pitch action was reduced while the output power was smoothed. To demonstrate the effectiveness of the designed strategy, comparative experiments were conducted with methods such as gain scheduling PI control in various wind scenarios. Results show that the proposed control strategy enables the floating offshore wind turbine to meet the stability of power generation while reducing the pitch motion of the floating platform, which can significantly reduce the fatigue damage of the floating offshore wind turbine.
    • Green Energy and Low-carbon Technology
  • Green Energy and Low-carbon Technology
    Performance Study of Solid Polymeric Denitrification Agent in SNCR Denitrification Process
    TANG Jing, OUYANG Haodong, SUN Wentao, WU Yachang, LIU Zishu, ZHAO Li
    2024, 44(4): 616-621. https://doi.org/10.19805/j.cnki.jcspe.2024.230079
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    Due to the traditional non-catalytic reduction denitrification (SNCR) technology using urea or ammonia as reducing agents has problems such as decomposition of the reducing agent is insufficient, reaction temperature is high, and denitrification efficiency is low, solid denitrification agent can be used to overcome the above problems. A solid polymeric denitrifier was prepared with melamine, urea and formaldehyde as matrix. And the effects of reaction temperature, O2 volume fraction, H2O volume fraction, residence time and ammonia-nitrogen ratio on reaction activity were analyzed. Results show that the active temperature window of solid polymer denitration agent is lower than that of conventional reducing agent. When the volume fraction of O2 is 1.2%, the denitrification efficiency reaches the highest by 84.2%, and when the volume fraction of H2O is 1.4%, the denitrification efficiency reaches the highest by 91.4%. However, the effect of residence time on the reactivity activity of denitrification agent is not obvious. While the effect of ammonia nitrogen ratio is more obvious. When the ammonia-nitrogen ratio is 1.5, the denitrification efficiency is the highest.
  • Green Energy and Low-carbon Technology
    Study on Mechanism Model and Key State Variables of Air Pollutants in Circulating Fluidized Bed
    JIANG Haiwei, GAO Mingming, ZHANG Kaiping, ZHANG Yifan, YUE Guangxi
    2024, 44(4): 622-631. https://doi.org/10.19805/j.cnki.jcspe.2024.230199
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    Based on the technology of desulfurization, self-denitrification and selective non-catalytic reduction (SNCR) denitrification in circulating fluidized bed (CFB), the emission of air pollutants from CFB units was studied. The combustion model, the pollutant generation and removal model in CFB units were established, and the key state variables affecting the emission of pollutants were analyzed. Results show that the established models of SO2 and NOx emission of CFB units can fit the actual operation data well, and have certain prediction effect and strong model universality. The combustion of carbon affects the reduction atmosphere in the furnace, which significantly affects the reduction of NOx. The amount of active limestone and furnace temperature is the main factors affecting the curing reaction between SO2 and active limestone, while relatively high furnace temperature and less active limestone stock will both increase the concentration of SO2 emission, but the higher the temperature is, the lower the level of NOx emission is.
  • Green Energy and Low-carbon Technology
    Research on Prediction of CO2 Enrichment Characteristics and NOx Generation During Oxygen-enriched Combustion of Pulverized Coal
    YAN Zhenrong, ZHONG Buyi, HU Chao, ZHANG Tao, HE Xiang, XIA Jie, TENG Lan, DA Yaodong
    2024, 44(4): 632-640. https://doi.org/10.19805/j.cnki.jcspe.2024.230700
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    The characteristics of pulverized coal combustion, CO2 enrichment and NOx generation during the oxygen-enriched combustion were analyzed. The synergistic control of CO2 enrichment and NOx generation was simulated. Results show that compared with air combustion, the negative synergistic effect between CO2 enrichment and NOx volume fraction distribution during the oxygen-enriched combustion can be observed. Under different O2/CO2 volume fractions, as the oxygen volume fraction increases, the volume fractions of both CO2 and NOx at the furnace outlet increase to the maximum firstly and then decrease slightly, showing the positive synergistic effect, but the turning point of the oxygen volume fraction is different. When enriched CO2 volume fraction exceeds a certain value, it can effectively inhibit the NOx generation. Under enriched oxygen conditions, a synergistic control technology can be achieved for high CO2 enrichment and low NOx generation at the furnace outlet.
  • Green Energy and Low-carbon Technology
    Prediction of SO2 Emission Mass Concentration Based on Improved INFO-Bi-LSTM Algorithm
    WANG Qi, CHAI Yuhuan, WANG Pengcheng, LIU Baichuan, LIU Xiang
    2024, 44(4): 641-649. https://doi.org/10.19805/j.cnki.jcspe.2024.230184
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    In view of the problem that it is difficult to accurately predict the SO2 emission mass concentration of thermal power units due to numerous influencing factors, a combined model named as improved INFO-Bi-LSTM model was proposed with the combination of improved weighted mean of vectors (INFO) algorithm and bi-directional long short term memory (Bi-LSTM) neural network. The high quality initial population was generated by adopting Circle chaotic mapping and reverse learning, while the ability of jumping from local optimal solution and global searching of INFO algorithm was improved with the application of adaptive t-distribution. Improved INFO-Bi-LSTM model and several other prediction models for a combined desulfurization process inside and outside the furnace were selected to predict the SO2 emission concentrations under four typical conditions, after which, verifications and comparisons were conducted on the prediction results. Results show that, the optimization ability of INFO algorithm is improved, while improved INFO-Bi-LSTM model has a higher accuracy, and which is more suitable for the application of SO2 mass concentration prediction. This can provide a reference for control theory in flue gas desulfurization process under variable conditions.
    • Integrated Energy System
  • Integrated Energy System
    Integration and Optimal Allocation of Integrated Energy System Based on Source Side of Thermal Power Plant
    YUN Panfeng, XU Shuhan, DAN Huijie, ZHANG Min, NIU Guoping, MENG Yi
    2024, 44(4): 650-657. https://doi.org/10.19805/j.cnki.jcspe.2024.230191
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    An integrated energy system based on source side of thermal power plant was proposed,which takes thermal power units as the core, couples multiple renewable energy inputs such as biomass gasification, garbage gasification and dried sludge at the input end of the system, and supplies multiple energy products such as colding, heating, steam and electricity at the output end. By coupling the thermal balance model of the power plant with the renewable energy model and cooling/heating system model, an optimization configuration method was established with efficiency and economy as the objectives. The following two types of optimization logics, input optimization and output optimization, were adopted to analyze the impact of the main operating parameters of the integrated energy system on the economy and efficiency optimization goals from the input and output ends of the system. Results show that integrated energy transformation has positive significance for current thermal power plants.
  • Integrated Energy System
    Multi-objective Optimization of Supercritical CO2-Organic Rankine Combined Cycle
    HOU Shengya, YANG Qiguo
    2024, 44(4): 658-664. https://doi.org/10.19805/j.cnki.jcspe.2024.230137
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    A composite supercritical carbon dioxide-organic Rankine combined cycle was used for waste heat recovery from the gas turbine, comprehensive thermodynamic and exergy economic model was established, and the impact of key parameters on the performance of the combined cycle system was explored. A study has been carried out on the combined cycle system from multiple purposes such as thermodynamic performance, space compactness and exergy economic performance, so as to conduct the multi-objective optimization on the combined cycle. Results show that the combined cycle efficiency in the optimal state can reach 54.56%, which is 4.2% higher than that of the conventional gas turbine-steam combined cycle. The required heat exchange area per unit power output is 0.117 8 m2/kW, which is 21.41% lower than that of the conventional gas turbine-steam combined cycle.