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  • Research & Analysis
    Multi-objective Optimization for Supercritical Carbon Dioxide Recompression Brayton Cycle
    Zhang Shurong, Sun Yeshan, Tan Luzhi, Wang Mingtao, Zang Hangyu, Li Yanan
    2022, 36(1): 1-5. https://doi.org/10.19806/j.cnki.fdsb.2022.01.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A multi-objective optimization model was established for the optimization of the supercritical carbon dioxide recompression Brayton cycle, and the effects of following key parameters on the performance of the system were researched, such as the split ratio, the pressure ratio, the inlet pressure of the main compressor and the inlet temperature of the turbine. After which, the comprehensive evaluation was carried out.Results show that, with the increase of the split ratio,the multi-objective function increases at first and then decreases, and the split ratio has an optimal value. With the increase of the inlet pressure of the main compressor, the multi-objective function and the system thermal efficiency both decrease. The higher the inlet temperature of the turbine is, the lower the multi-objective function will be. Four key parameters all have a great effect on the effectiveness of the regenerator and the performance of the cycle.
  • Research & Analysis
    Numerical Simulation on Supersaturation Field in a Single-channel Cooling System with Circulation Reflux
    Ye Xiaohui, Zhang Jun, Lü Li, Dai Anwen, Yin Jie
    2022, 36(1): 6-10. https://doi.org/10.19806/j.cnki.fdsb.2022.01.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To research the effect of circulation reflux on the supersaturation field, taking a single-channel flue gas cooling system as the research object, the effects of following three factors on the supersaturation field were analyzed, such as the reflux ratio, the reflux extraction point and the reflux injection point. Results show that compared with no reflux, the supersaturation can be increased by adopting circulation reflux. The reflux ratio has a great influence on the supersaturation, and the outlet average supersaturation increases with the increase of the reflux ratio. The reflux extraction point is the second factor in influencing the outlet average supersaturation, and the optimal reflux extraction point is related to the reflux ratio. The reflux injection point has a great influence on the uniformity of the supersaturation distribution, while which has a relatively small influence on the outlet average supersaturation. The farther the reflux injection point is away from the first tube, the more uniform the supersaturation distribution will be.
  • Research & Analysis
    Experimental Study on Surface Temperature Measurement of Zhundong Coal Particles During Combustion
    Cai Chuanqi, Lü Weizhi
    2022, 36(1): 11-15. https://doi.org/10.19806/j.cnki.fdsb.2022.01.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To research the particle surface temperature and the combustion characteristics of Zhundong coal during the combustion process, a temperature measurement system for burning pulverized coal particles was established, meanwhile, through burning Zhundong coal, lignite and two kinds of bituminous coals, the curves of the particle surface temperature with the burner nozzle height of above four samples were obtained. Results show that the curves of the particle surface temperature of the four samples are similar. Zhungdong coal has the most drastic combustion process with the brightest fire among the four samples, which corresponding to the highest particle surface temperature and the best combustion characteristic. This indicates that the ash content and the alkali and alkaline earth metals content are important factors in affecting the particle surface temperature.
  • Research & Analysis
    Study on Combustion Mechanism of Waste Ion Exchange Resins
    Ma Guilin, Liu Meng
    2022, 36(1): 16-21. https://doi.org/10.19806/j.cnki.fdsb.2022.01.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The combustion mechanism of three kinds of waste ion exchange resins (WIERs) was studied by using thermogravimetric analysis and chemical reaction kinetics. Results showed that the three kinds of WIERs have similar combustion characteristics, while all the WIERs contains more bound water and volatile matter. The activation energy of the bound water release stage is 12.31-41.12 kJ/mol, which is close to that of the volatile matter release stage. With the increase of temperature rise rate, the bound water release stages of the three WIER combustion processes coincide more largely with the volatile matter release stages. Through comparing 12 reaction mechanisms of the three kinds of WIERs, the most generalized mechanism functions of the bound water release stages all are G-B equations, while those of the volatile mater release stages are different.
  • Research & Analysis
    Seismic Analysis on SBO Diesel Generator Set in a Nuclear Power Plant
    You Guoying, Ye Changzheng, Liu Yinfang
    2022, 36(1): 22-26. https://doi.org/10.19806/j.cnki.fdsb.2022.01.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Seismic analyses were conducted on a SBO (station black-out accident condition) diesel generator set in a nuclear power plant. Mechanical models were established for the assembly set, the power generator and the diesel engine by SolidWorks software and PATRAN software, while static mechanical analysis,modal analysis and seismic response analysis were carried out for the models by ANSYS software and NASTRAN software. After which, according to RCC-M standard, structural stress and deformation were evaluated under various load combinations. Results show that, under normal condition and faulted condition, both of structural stress and deformation are less than allowable values. The design of the diesel generator set can satisfy the requirements of relevant standards.
  • Research & Analysis
    Study on Torsional Vibration Characteristics of Turbomachinery Shafting with Gear and Hydraulic Torque Converter
    Gao Jin, Feng Guoyi
    2022, 36(1): 27-31. https://doi.org/10.19806/j.cnki.fdsb.2022.01.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on ANSYS software, studies were conducted on torsional vibration characteristics of a turbomachinery shafting with a gear and a hydraulic torque converter through using user defined Matrix27 stiffness element to model the torsional stiffness of the gear pair, and using user defined Matrix27 damping element to model the damping between the pump impeller and the turbine vane of the hydraulic torque converter. Results show that, with the increase of the meshing stiffness of the gear pair, the torsional vibration frequency of the shafting tends to be constant; meanwhile, the damping between the pump impeller and the turbine vane of the hydraulic torque converter has little effect on the torsional vibration frequency of the shafting, which presents a good isolation effect of the hydraulic torque converter on the torsional vibration excitation of the shafting.
    • New Energy
  • New Energy
    Study on the Combustion Behavior of Biomass in Oxygen-enhanced Atmosphere
    Li Hao, Jing Huixiang, Lu Bingju, Zou Chun
    2022, 36(1): 32-36. https://doi.org/10.19806/j.cnki.fdsb.2022.01.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The ignition characteristics of three kinds of biomass were investigated under O2/N2 atmosphere with different O2 mole fractions, where the biomass particle sizes ranged from 500 to 700 μm and O2 mole fractions were 21%, 30%, 50%, 70% and 100%. The results show that the O2 mole fraction determines the transformation of the biomass ignition mechanism. With the increase of O2 mole fraction, the ignition mechanism of rice husk, bamboo and soybean stalk changes from homogeneous ignition to heterogeneous ignition at 100%, 70% and 30% O2 mole fraction, respectively. O2mole fraction can affect the ignition distance and burnout time of the three kinds of biomass, and both the ignition distance and burnout time decrease with the increase of O2 mole fraction.
    • Design & Manufacture
  • Design & Manufacture
    Analysis and Optimization on Failure of Water Wall Corner in a 660 MW Tower Boiler
    Sha Yuanchao, Wei Hongqi, Wang Chao, Hu Shanmiao
    2022, 36(1): 37-41,46. https://doi.org/10.19806/j.cnki.fdsb.2022.01.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem that the crack failure occurred frequently at the corner of the vertical section water wall in a 660 MW tower boiler, based on ANSYS Workbench software, analyses were conducted on the reason of cracks at the corner of the water wall, and optimization schemes were proposed for the failure. Analysis results show that the crack failure at the corner of the vertical section water wall is caused by the stress concentration, which is resulted from the structure design defect of the rigid beam corner device. With the optimized rigid beam corner device, the stress concentration could be alleviated, and the probability of the crack failure at the corner of the vertical section water wall could be reduced.
  • Design & Manufacture
    Effects of Flue Gas Recirculation Position on Reheat Steam Temperature in a Boiler
    Shen Yingqiang, Wu Huadong, Li Yongjin, Tao Shengzhi
    2022, 36(1): 42-46. https://doi.org/10.19806/j.cnki.fdsb.2022.01.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a 660 MW ultra-supercritical boiler as the research object, based on thermal calculation model, the effects of flue gas recirculation on following parameters were researched and analyzed when introducing the recirculation flue gas into the boiler from the burner bottom (scheme Ⅰ) and from the panel bottom at the furnace outlet (scheme Ⅱ), respectively, such as the flue gas temperature at furnace outlet, the reheat steam temperature, etc. Results show that the reheat steam temperature can be improved effectively with adopting flue gas recirculation. With an increase of one percentage point of the recirculation rate, the primary and the secondary reheat steam temperature of scheme Ⅰ are increased by about 2.0 K, while those of scheme Ⅱ are increased by about 0.44 K. Scheme Ⅰ is superior to scheme Ⅱ.
    • Material Technology
  • Material Technology
    Evaluation of Tensile Properties of P92 Steel by Means of Small Punch Test
    Shi Kexian, Yang Changshun, Shao Xinzhong, Wang Miaomiao, Tian Genqi, Wang Yanfeng
    2022, 36(1): 47-52. https://doi.org/10.19806/j.cnki.fdsb.2022.01.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The tensile properties of P92 steel, a domestic main steam pipe material, were investigated by means of small punch test technology based on micro loss sampling. The results show that the test machine and method have good repeatability. The results of loading rates of 0.2 mm/min and 0.5 mm/min are close, while the results of 2 mm/min are quite different. The yield strength at 25-650℃ can be well estimated by using the yield strength correlation formula at room temperature. When the sample thickness is determined, the estimation error can be effectively reduced by the appropriate fitting formula.
    • Environmental Technology
  • Environmental Technology
    Experiment and Application of Dry Ice Cleaning Denitration Catalyst
    Liu Bin, Chen Chen, Zhao Yuepeng, Li Jun, Zhu Xiaolei
    2022, 36(1): 53-57. https://doi.org/10.19806/j.cnki.fdsb.2022.01.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The dry ice cleaning technology was developed to solve the problem that the selective catalytic reduction (SCR) denitration catalyst of large thermal power units accumulates ash, blocks and decreases in activity, while the new soot blowers such as compressed air soot blower, sonic waves soot blower and steam soot blower cannot achieve efficient soot blowing, and regeneration technology cannot achieve online in-situ regeneration. The application of this technology at some kind of 150 MW unit SCR denitration catalyst can effectively remove the ash scale of ammonium bisulfate (ABS) in the catalyst micropores, greatly increase the specific surface area, reduce the heavy metal content, and improve the catalyst activity.
    • Automatic Control
  • Automatic Control
    Research on Control for Preheating Antifreeze System of a Natural Draft Cooling Tower
    Jin Qinghui, Song Chuanjiao, Yang Jianming, Huang Enhe, Yao Liping
    2022, 36(1): 58-65. https://doi.org/10.19806/j.cnki.fdsb.2022.01.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A preheating antifreeze system was proposed by adopting the high-temperature circulating water at the outlet of the condenser to heat the cold air, and a mathematic model was established for flow and heat transfer. Meanwhile, for a 1 000 MW unit, a model with the antifreeze constraint was established for operation control, and the antifreeze effect was verified. After which, the optimal control parameters were given. Research results show that, by using the antifreeze system, the inlet air temperature can be increased for avoiding freeze, while the circulating water can be cooled. When the ambient temperature or the unit load decreases, the regulating valve opening should be increased in priority to ensure that the inlet air temperature is higher than the antifreeze threshold by increasing circulating water flow, but after reaching the upper regulating limit of the circulating water flow, the control shutter opening should be decreased to reduce the ventilation flow. Through the optimization control, the outlet water temperature of the cooling tower can be maintained at 3-12℃, and the heat consumption of the unit can be reduced by 60.70 kJ/(kW·h) on average. This presents a significant economy.
    • Operation & Retrofit
  • Operation & Retrofit
    Cause Analysis and Strategy for Large Differential Pressure of Air Preheater in a 350 MW Coal-fired Unit
    Mu Fuyi, Zhao Kai
    2022, 36(1): 66-70. https://doi.org/10.19806/j.cnki.fdsb.2022.01.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of large differential pressure at the flue gas side of air preheater in a 350 MW coal-fired unit, relevant information including coal quality, low temperature corrosion at cold end, soot blowing and flushing of air preheater was analyzed. It was confirmed that insufficient output of secondary air heater should be responsible for the low temperature corrosion of air preheater. Based on that, retrofit of secondary air heater and drainage system was carried out which led to the rise of cold end temperature of air preheater. Besides, an analysis of the influence on the unit economy was also conducted. The results show that after the retrofit of air heater, the differential pressure at the flue gas side of air preheater returns to normal level, and the problem of the low temperature corrosion at cold end of air preheater can be solved out.
  • Operation & Retrofit
    Analysis and Optimization on Primary Frequency Control of an Ansaldo AE94.3A Gas Turbine
    Xiao Xinyu, Shi Yiyue, Tang Keyi, Gao Aimin, Zhang Tianhai
    2022, 36(1): 71-74. https://doi.org/10.19806/j.cnki.fdsb.2022.01.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem that the response index of primary control cannot meet the power grid requirement in an Ansaldo AE94.3A gas turbine, following measures were conducted for the optimization of the original control strategy, such as keeping the primary frequency control separating from the feedforward, retaining the load set point feedforward with speed limit, and superimposing the primary frequency control onto the load set point to compensate the power closed loop. Results show that, after optimization, the integral power of the primary frequency control is improved significantly, and every performance index can meet the power grid requirement.