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  • Research & Analysis
    Simulation of Condensate Water Throttling Dynamic Process in Coal-fired Units Based on Dymola
    FAN Xian, LI Yanfei, HOU Wenhao, DONG Jingui, WANG Dong, ZHANG Pengwei, SHI Xuetong, LI Jiangping
    2025, 39(4): 211-218. https://doi.org/10.19806/j.cnki.fdsb.2025.04.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A simulation method for the condensate water throttling dynamic process in coal-fired units based on Dymola software was proposed. For a 350 MW supercritical unit, a dynamic simulation of the condensation water throttling process under automatic generation control (AGC) condition was conducted. The dynamic process and primary control and regulation model of the coal-fired unit was developed, and the accuracy of the model was verified. By simulating the impact of the condensate water throttling on the dynamic characteristics of the coal-fired unit, the response rates of the coordinated control system (CCS) lifting and lowering loads of 90% and 75% thermal heat acceptance (THA) conditions were compared with those of the traditional CCS lifting and lowering loads under the condensate water throttling conditions. The simulation results indicate that the CCS involving condensate water throttling can respond quickly to the lifting and lowering load commands, and the load response rate of the unit is significantly higher than that in the traditional coordinated case. Additionally, the condensate water throttling process has minimal effects on the main steam and reheated steam temperature/pressure of the unit.
  • Research & Analysis
    Research on Type Ⅰ Boundary and Type Ⅱ Boundary of TP347H/12Cr1MoV Dissimilar Metal Welded Joint Aged at High Temperature
    TAN Qi, GU Zhongyan, ZHANG Songwen, ZHOU Hao, GUO Derui, WANG Qingfeng, CHEN Xin
    2025, 39(4): 219-223,228. https://doi.org/10.19806/j.cnki.fdsb.2025.04.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to explore the influence of type Ⅰ and type Ⅱ boundaries in the weld of TP347H/12Cr1MoV dissimilar metal welded joint after high temperature aging treatment on the microstructure and properties of the joint, CALPHAD method was employed, and Thermo-Calc software was utilized to study the equilibrium phase composition and precipitate behavior of the welded joints. The simulation results from Thermo-Calc software indicate that, under the same temperature at 600-800 ℃, the carbon activity in each alloy decreases in the order of 12Cr1MoV, weld, and TP347H. Considering the activity factor, the direction of carbon migration is from 12Cr1MoV to the weld at first and then to TP347H, which is consistent with the actual results of carbon migration. Additionally, the TP347H/12Cr1MoV welded joint was subjected to isothermal aging treatment at 650 ℃ for 1 500 h, then the microstructures and precipitate characteristics of type Ⅰ and type Ⅱ boundaries were analysed using metallographic microstructure observation, scanning electron microscopy, and energy dispersive spectroscopy. Results show that, the weld microstructure consists of a mixture of cellular and dendritic crystals. The solidification mode of the weld in the TP347H/12Cr1MoV welded joint is primarily the austenitic A-type solidification mode. After aging treatment, Cr-rich and Nb-rich phases appear in type Ⅰ and type Ⅱ boundaries of TP347H and weld interface.
  • Research & Analysis
    Evaluation Method for the Health Status of Electronic Weighing Coal Feeder
    PAN Xiaojie, LIU Linhui, ZHANG Weijie
    2025, 39(4): 224-228. https://doi.org/10.19806/j.cnki.fdsb.2025.04.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The electronic weighing coal feeder is an important auxiliary equipment in thermal power plants. Once a fault occurs, it will seriously affect the operation of the entire unit. The evaluation method of equipment health status can accurately reflect the status of the coal feeder and predict the future status of the equipment. By analysing the functions and common failures of the coal feeder, a health status evaluation model for the coal feeder was established. Combined with an expert knowledge base, a quantitative model integrating deviation and fluctuation indicators was proposed, and a comprehensive weighting method was used to calculate the health index of coal feeder equipment. Taking the CS2024 coal feeder as an example for testing and analysis, the results show that this method has high accuracy, practical value, and guiding significance in practical applications, and can provide a reference for the subsequent health status evaluation of electronic weighing coal feeders.
    • Power Equipment Optimization
  • Power Equipment Optimization
    Analysis and Optimization of Deformation in the High-Medium Pressure Inner Cylinder of a Supercritical 660 MW Unit Steam Turbine
    YANG Long, CHEN Jianglong, XU Kepeng, CHEN Chunfeng
    2025, 39(4): 229-233. https://doi.org/10.19806/j.cnki.fdsb.2025.04.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The deformation of the high-medium pressure inner cylinder of a supercritical 660 MW unit steam turbine under working conditions was analysed and calculated using the finite element method. The radial deformation at different axial positions of the cylinder was obtained, and improvement and optimization measures were proposed. The analysis results show that under steady-state operating conditions, the radial deformation of the cylinder exhibits a vertical elliptical shape in the middle section and more flattened ellipses at both ends, with higher ellipticity at the ends. After analysing the causes of deformation and adopting improvement measures, the radial deformation ellipticity of the cylinder is significantly reduced. The maximum reduction in ellipticity is 60% in the high-pressure section and 90% in the medium-pressure section. The maximum ellipticity is reduced from -1.47 mm to -0.34 mm. The improvement is evident and beneficial for the design and adjustment of the steam seal clearance.
  • Power Equipment Optimization
    Analysis of the Impact of an Integrated Steam Chamber Structure in the Cylinder on Stiffness and Flange Sealing
    GUO Yi, LIU Dianwei, ZHANG Peijuan, GAO Kaixiang, ZHUO Yunbo
    2025, 39(4): 234-237. https://doi.org/10.19806/j.cnki.fdsb.2025.04.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The impact of adopting an integrated steam chamber structure in the cylinder on stiffness and flange sealing was discussed. Through finite element calculations and analyses, compared with the conventional independent steam chamber structure, the integrated design can not only significantly reduce the deformation of the cylinder upper arch, avoid the friction between the steam chamber seal and the rotor during operation, but also reduce the deformation of the opening at the upper cylinder steam chamber, and solve the problem of performance reduction of the flange sealing caused by deformation. Cylinders with an integrated steam chamber structure can meet the requirements for long-term, efficient, and safe operation of the unit and also provide an engineering example for designing steam turbines with higher extraction steam pressures.
  • Power Equipment Optimization
    The Application of the Finite Element Method in the Design of Steam Turbine Hydrostatic Test
    ZHANG Wei, CHEN Jianglong, XU Kepeng, CHEN Chunfeng
    2025, 39(4): 238-241. https://doi.org/10.19806/j.cnki.fdsb.2025.04.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The finite element method was employed to simulate the working condition of the high-pressure and intermediate-pressure integrated inner casing of a 660 MW supercritical unit steam turbine under hydrostatic test conditions. The hydrostatic test plan and the bolt tightening force requirements were determined. Moreover, the hot-tightening nut rotation angle during installation was derived through practical application, forming a complete design and analysis process for the hydrostatic test of high-parameter cylinders. Through optimized design, the plan ensures the structural strength safety of the cylinders while effectively meeting the sealing requirements of the hydrostatic test. The research results provide a reference for the hydrostatic test of other high-parameter units.
  • Power Equipment Optimization
    Optimization of Lubricating Oil Exhaust System in M701F4 Gas Turbine
    CUI Yongjun, WU Yanjun, ZHAO Tian, CAO Yu, LIU Xiaokun
    2025, 39(4): 242-247. https://doi.org/10.19806/j.cnki.fdsb.2025.04.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem that the negative pressure of gas turbine lubricating oil tank in existing units needed to be adjusted frequently, a scheme was proposed for optimizing the transformation of gas turbine lubricating oil exhaust fan by variable frequency conversion, and investigations were conducted on the remote adjustment effect of the negative pressure of lubricating oil tank in gas turbine within full load range. Operation data show that the negative pressure can be flexibly and accurately controlled within the specified value range after the variable frequency conversion, thus reducing the fire risk of gas turbine, improving the stability of lubricating oil exhaust system, reducing the power consumption rate of the plant, and achieving the purpose of energy saving and consumption reduction.
  • Power Equipment Optimization
    Overview and Treatment on the Blockage of Rotary Air Preheaters in Coal-fired Units
    CHONG Xihu, NING Xinyu, HU Lei, LIU Zhongxuan
    2025, 39(4): 248-256. https://doi.org/10.19806/j.cnki.fdsb.2025.04.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A survey was conducted on 125 coal-fired units of a power generation group, listing the blockage conditions of the rotary air preheater of the sample units and analysing the factors affecting the blockage of air preheaters. At the same time, treatment ideas and countermeasures for the blockage problem of air preheaters were proposed, and four types of anti-blocking technologies for air preheaters were compared and analysed, including precise ammonia injection technology, optimization and transformation technology of new anti-blocking heat transfer elements, addition of heat pipe air preheater technology, and air volume segmentation anti-blocking technology. Results show that, precise ammonia injection technology, as the main active defense method, mainly slows down or eliminates the blockage problem of air preheaters by reducing the ammonia escape in the upstream of air preheaters, with the characteristics of less transformation and low investment. The optimization and transformation technology of new anti-blocking heat transfer elements, addition of heat pipe air preheater technology, and air volume segmentation anti-blocking technology, as passive defense technologies, mainly slow down or eliminate the blockage problem of air preheaters by transforming the structure of air preheaters and optimizing operating boundary conditions, with the characteristics of large transformation and high investment. Different power plants need to choose economic and reliable technical solutions according to their actual situations.
    • Energy Conservation and Environmental Protection Technology
  • Energy Conservation and Environmental Protection Technology
    Economic Analysis of Replacing Natural Gas with Membrane Separation Tail Gas as Fuel for Gas Turbines
    MIAO Chen, ZHANG Liwen, SHENG Zhenxing, ZHANG Hailong, LIU Chengyuan, LI Chendi
    2025, 39(4): 257-261. https://doi.org/10.19806/j.cnki.fdsb.2025.04.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the gas turbine performance model and combined with field temperature data and gas turbine performance test data, an economic model was established to predict the monthly and hourly variations of the unit output power, exhaust temperature and fuel flow rate more accurately. Through calculations using the economic model, the average monthly revenue of the entire project after replacing natural gas with membrane separation tail gas is approximately 48.523 2 million yuan, indicating significant economic benefits. Replacing natural gas with membrane separation tail gas as fuel not only achieves efficient operation of gas turbines, but also ensures the green utilization of membrane separation tail gas.
  • Energy Conservation and Environmental Protection Technology
    Application and Economy Analysis of Medium-temperature and Medium-pressure Steam Turbines in Gas Oxidation Power Engineering
    SHAO Jianbo
    2025, 39(4): 262-266,280. https://doi.org/10.19806/j.cnki.fdsb.2025.04.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Focusing on medium-temperature and medium-pressure superheated steam power generation technology, the working principles and characteristics of two currently more mature technologies were introduced in detail. Taking a low-concentration gas oxidation device that produces superheated steam as the research object, specific plans were developed using these two power generation technologies, and a comparative analysis was conducted from both economic and technical perspectives. The research results show that plan 1 is superior to plan 2 in terms of technical feasibility, economic cost, and comprehensive benefit, and it is more suitable for application in the field of superheated steam power generation of low-concentration gas oxidation devices. The findings can serve as a reference for the equipment selection and technologies application.
  • Energy Conservation and Environmental Protection Technology
    Deep Coupling Technology for Waste Heat of Flue Gas and Closed-loop Cooling Water in a Coal-fired Boiler
    CAO Wei, GONG Chenliang, LI Jiahui, JIAN Yuxiang, JIN Jiuxiang, LIN Mingquan, LIU Qi, WANG Xiaolu
    2025, 39(4): 267-272. https://doi.org/10.19806/j.cnki.fdsb.2025.04.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a waste heat retrofit project of a 1 000 MW coal-fired unit in southern China as an example, and combining heat pump and air preheater bypass waste heat utilization technology, the waste heat in flue gas was deeply coupled with the waste heat in closed-loop cooling water to maximize the utilization of low-grade waste heat in closed-loop cooling water. Under design condition, the net coal consumption rate can be reduced by 3.87 g/(kW·h), with 0.25 g/(kW·h) of savings attributed to the waste heat in closed-loop cooling water. Under winter condition, the net coal consumption rate can be reduced by 3.16 g/(kW·h), with 1.34 g/(kW·h) of savings attributed to the waste heat in closed-loop cooling water. The static payback period for this retrofit scheme is 2.1 years. The economic performance of the unit can be effectively improved by utilizing low-grade waste heat to replace the high-grade steam thermal energy of steam air heater.
    • New Energy Technology
  • New Energy Technology
    Intelligent Prediction of Heat Transfer Characteristics During Biomass Particle Pyrolysis
    SONG Xiaoan, YIN Lijie, HUANG Jingkuan, YE Na
    2025, 39(4): 273-280. https://doi.org/10.19806/j.cnki.fdsb.2025.04.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    During the pyrolysis process of large-sized biomass particles, significant temperature gradients develop within the particles, which have an important impact on the heat transfer and reaction processes. Centimeter-scale biomass spheres were used as the research subject. Numerical simulations were conducted to investigate the effects of heating gas flow rate, temperature, and particle diameter on the internal temperature distribution, heat transfer characteristics, and weight loss rate/reaction time during pyrolysis. Results show that the temperature distribution along the particle diameter in the flow direction is U-shaped. Compared with the flow rate and temperature of the heating gas, the particle size has a more significant influence on the pyrolysis process. The pyrolysis time required for a particle with a diameter of 30 mm is 10.31 times that of a particle with a diameter of 5 mm. A weight loss model for particle pyrolysis based on back propagation (BP) neural network was established, which can effectively reduce computational costs while accurately predicting the heat transfer and reaction characteristics during the pyrolysis process. This approach is importance for the control of the pyrolysis process and the design of pyrolysis reactors.