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    Research & Analysis
  • Research & Analysis
    Optimization for the Whole Process Flow Field of Rear Gas Flue in a Coal-Fired Unit
    Zhao Zibin, Chen Cheng, Li Rongchun, Li Jianning
    2023, 37(2): 75-81. https://doi.org/10.19806/j.cnki.fdsb.2023.02.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To further explore the energy-saving potential of the air flue system in coal-fired units, an analysis and optimization was conducted on the whole process flow field including following parts of the rear gas flue in a coal-fired unit based on numerical simulation, such as the outlet of the air preheater to the inlet of the electrostatic precipitator, the inlet of the electrostatic precipitator to the inlet of the induced draft fan, and the outlet of the induced draft fan to the inlet of the desulfurization tower. While the simulation results and the engineering application results were compared. Results show, after the simulation optimization, the resistance of the rear gas flue system is reduced by 205 Pa, the flue gas velocity deviation of each economizer is less than 20%. The simulation results are in good agreement with the engineering application results. The safety and economy of the unit operation can be improved by adopting the proposed flue flow field optimization and energy-saving coupling technical scheme for large coal-fired units.
  • Research & Analysis
    Cracking Analysis and Stress Optimization for HR3C Tube Panel of the High-temperature Reheater in an Ultra Supercritical Boiler
    Liu Changfu, Shen Kang, Guo Derui, Du Shuangming, Li Shuai, Yang Mingchang
    2023, 37(2): 82-88. https://doi.org/10.19806/j.cnki.fdsb.2023.02.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of the cracking occurring at the inner arc of the cold bend tube of the secondary high-temperature reheater in an ultra supercritical boiler with the operation time of about 2 000 h, researches and analyses were conducted on the reason according to the stress distribution. Results show that, the bend tube has the normal metallographic structure and the qualified tensile strength at room temperature. It is found that the cracking has the obvious characteristics of intergranular oxidation defects. The stress is significantly influenced by the ellipticity of the bend section, while the residual stress caused by the lacking step of solution treatment for the cold bend is still existed. The generation and expansion of the intergranular oxidation defects is promoted by the residual stress, which finally leads to the cracking of the tube panel during operation. There is no cracking occurring at the tube panel during operation with following optimization measures, such as controlling the ellipticity of the bend section, carrying out the solution treatment, improving the installation, etc.
  • Research & Analysis
    Analysis and Comparison on Economy of Extracting Steam Heat-supply with Rotating Board and from Hot Reheat Piping in a 350 MW Supercritical Unit
    Huang Xinchang
    2023, 37(2): 89-93. https://doi.org/10.19806/j.cnki.fdsb.2023.02.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To analyze the operation economy of a 350 MW supercritical unit with extracting steam heat-supply under different conditions, a heat balance calculation method was established based on the actual operation data, and a calculation and comparison was conducted on the economy of the extracting steam heat-supply with rotating board and from hot reheat piping. Results show that, the efficiency the medium-pressure cylinder is reduced with the commissioning of the rotating board, and both of the benefit of above two heat-supply methods can be improved with different increase ranges under the same heat-supply condition.
  • Research & Analysis
    Exergy Analysis of a 600 MW Subcritical Coal-fired Boiler
    Jiao Kaiming
    2023, 37(2): 94-97. https://doi.org/10.19806/j.cnki.fdsb.2023.02.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For a 600 MW subcritical coal-fired boiler, based on the thermal analysis method and the exergy analysis method, the influence of the feedwater temperature and the exhaust gas temperature on the exergy efficiency was analyzed and researched. Results show that, the exergy efficiency of the boiler can be improved by reducing the exhaust gas temperature or increasing the feedwater temperature. This may serve as a reference for energy-saving diagnosis of similar coal-fired boilers.
    • New Energy
  • New Energy
    Research on Maximum Power Point Tracking Algorithm for Photovoltaic Power Generation System Based on MATLAB/Simulink
    Wang Jin
    2023, 37(2): 98-103. https://doi.org/10.19806/j.cnki.fdsb.2023.02.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on MATLAB/Simulink software, a photovoltaic power generation system was established for the research of the influence of the environment on the output power of the photovoltaic cell, and an algorithm of maximum power point tracking (MPPT) was proposed. Meanwhile, the feasibility of the control algorithm was verified by simulating the actual environment. Results show that, the variation of light intensity, especially the weakening of light intensity, has a significant impact on the effect of tracking the maximum power point of the photovoltaic power generation system.
    • Material Technology
  • Material Technology
    Analysis on the Axial Crack of Weld Joint of the New-Old Low Temperature Superheater Tube in a Coal-fired Power Plant
    Peng Yishu
    2023, 37(2): 104-108. https://doi.org/10.19806/j.cnki.fdsb.2023.02.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of the leakage in the weld joint between the new and old low temperature superheater tube found during water pressure test in a coal-fired power plant, analyses and discussions were conducted on the leakage reason of the low temperature superheater through the test of macroscopic morphologies, microstructure and mechanical properties for the leakage sample. After which, corresponding countermeasures were proposed for this type of defect. Results show that the penetrating end crack is formed in the process of tube machining deformation, while the defects in the blind areas at the both ends are not completely removed in later tube selecting. The proposed countermeasures can serve as a reference for the quality management of the heat transfer tubes in boilers.
    • Environmental Technology
  • Environmental Technology
    Optimization and Adjustment for Ammonia Injection in SCR Denitrification System of a 600 MW Opposed Firing Boiler
    Pan Juanqin, Peng Zhifu
    2023, 37(2): 109-113,118. https://doi.org/10.19806/j.cnki.fdsb.2023.02.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem that the valve adjustment of the ammonia injection branch pipe can not meet the requirement of fully load operation of the selective catalytic reduction (SCR) denitrification system of a 600 MW opposed firing boiler, an adjustment strategy with load consideration was proposed. Results show that, through adopting the adjustment strategy with load consideration for the ammonia injection branch pipe, for the two sides of the denitrification system, the average values of the relative standard deviation of oxynitride (NO<i>x) mass concentration are decreased by 18.52 percentage points and 25.87 percentage points, while the average values of ammonia injection volumetric flow rate are decreased by 20.7 m3/h and 27.0 m3/h. The operation of denitrification system has been significantly improved.
    • Automatic Control
  • Automatic Control
    Improvement on the Adaptive Compensation Method for Actuator with Viscosity Characteristics
    Ma Xiaochun, Liu Xianghong, Zhao Weijie, Zheng Yunlin, Guo Li, Zhao Taotao
    2023, 37(2): 114-118. https://doi.org/10.19806/j.cnki.fdsb.2023.02.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the limitation that Kano viscosity model can not describe the time-varying viscosity parameters, a real-time calculation method of viscosity characteristics online detection and compensation including valve and connecting mechanism is proposed by introducing the position feedback signal of the actuator and the medium flow signal corresponding to the valve opening. Simulation results show that this method can overcome the influence of the change of dead zone and viscosity characteristics of the actuator, and effectively improve the control performance.
    • Operation & Retrofit
  • Operation & Retrofit
    Application of the Localization Retrofit for a 9FA Gas Turbine Control System with Simulation System
    Xiao Yancang, Wang Yong, Du Kai, Cao Weiping, Chen Zijing, Xiong Chao
    2023, 37(2): 119-125. https://doi.org/10.19806/j.cnki.fdsb.2023.02.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking the gas turbine control system (TCS) and digital electrohydraulic control system (DEH) in a S-109FA-SS single shaft gas and steam combined cycle unit as the research example for the localization retrofit, an introduction was presented for the modeling principle of the compressor, the combustion chamber and the turbine in the gas turbine, and the selection of main parameters, while the logic of gas turbine start-up phase and the thermal stress control algorithm of steam turbine were emphatically introduced. Through the simulation test in the application of typical cases, the accuracy of logic and control algorithm can be verified, and the design defects in the process of logic configuration can be eliminated in advance. It is confirmed that the simulation system plays an important role in the localization retrofit of gas turbine control system.
  • Operation & Retrofit
    The Adaptability Check of Equipment in Heat Recovery System of Heating Unit after Retrofitting
    Li Zhiwei, Zou Xiaoxin, Lin Baosen, Chen Xiaochen, Zhai Liming, Yu Jianzhong, Gong Yutong, Chen Delu
    2023, 37(2): 126-130. https://doi.org/10.19806/j.cnki.fdsb.2023.02.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To research the operation feasibility of the equipment in the heat recovery system in a heating unit after retrofitting, the adaptability of the equipment was checked, while the performance check was conducted on the high-pressure heater, the low-pressure heater, the condenser and the deaerator. Results show that, the shell-side strength check of the high-pressure heater can meet the parameter requirements after retrofitting, but the shell-side hydraulic pressure of the equipment should be retested, which is caused by the increase of the shell-side design pressure. The thermal performance check and the shell-side strength check of the low-pressure heater can meet the parameter requirements after retrofitting, but the retrofit may lead to the risk of the tube bundle vibration, which is caused by the increase of the steam velocity of the low-pressure heater. The operation of the condenser is safety with the thermal performance check and the shell-side strength check. The deaerator can basically meet the parameter requirements after retrofitting, while there would be a certain risk of vibration.
  • Operation & Retrofit
    Maintenance Optimization for Bearings of Low Pressure Cylinder in a 600 MW Subcritical Steam Turbine Unit
    Zeng Weiguang
    2023, 37(2): 131-135. https://doi.org/10.19806/j.cnki.fdsb.2023.02.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of the high temperature normally occurring at the bearings of low pressure cylinder in a domestic 600 MW subcritical steam turbine unit, the maintenance technology of the bearings of low pressure was optimized. Based on the comparison of the maintenance data and effects among several units, results show that, the cooling effect of lubricating oil can be improved through scraping the cuneiform oil bath in the bearings of low pressure cylinder, and decreasing the contact angle between the bearing neck and the bearing, while the temperature difference between the front and back measuring points in the bearing can be decreased by adjusting the bearing up-rising inclination in accordance with the bearing neck up-rising inclination. This may serve as a reference for the solution of the high temperature occurring at the bearings of low pressure cylinder in similar steam turbine units.
  • Operation & Retrofit
    Retrofit for the Performance Improvement of Medium-speed Mill in a Boiler Fired with Semi Coke
    Sun Ming, Zhang Zhifeng, Du Yongxu, Wang Hao, Huang Jinlong, Yao Panliang, Wang Lianzhao
    2023, 37(2): 136-140. https://doi.org/10.19806/j.cnki.fdsb.2023.02.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To analyze the influence of the using of semi coke on the output performance of the mill, and improve the output performance of the mill, a feasibility research was conducted on the performance improvement of a ZGM113K medium-speed mill in a power plant boiler. Test results show that, compared with the data before retrofitting, the output coal mass flow rate of the mill is increased by about 35% after retrofitting. The retrofit can satisfy the requirements of the boiler combustion with the qualified pulverized coal fineness.