Power Equipment

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  • 2016 Volume 30 Issue 4
    Published: 15 July 2016
      
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  • Modeling of HP Regenerative Heat Exchanger in Ultra-supercritical Steam Turbine Unit under Variable Conditions based on П Theory
    Yu Zhongping, Xu Jianqun
    2016, 30(4): 215-218.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A non-dimensional mathematical model (П theory) was built up for high-pressure regenerative heat exchanger according to actual measurements based on Buckingham theory to reflect its operation status under variable working conditions, which was then applied to the HP heater of a 660 MW ultra-supercritical steam turbine unit. Application results prove the model to be accurate, which may serve as reference for similar units.
  • Modeling Method of Turbine Speed Governing System in Thermal Power Units and its Optimization
    Yan Bo, He Jun, Qi Cong
    2016, 30(4): 219-222.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the model accuracy and reliability of a turbine speed governing system in thermal power units, and according to the overall requirements of the power system stability calculation on the model parameters, optimization ideas and methods were put forward from three aspects, namely the signal output and acquisition, the model measurement and building, and the simulation verification of model parameters. Also, the concept of "coordinated turbine governing system curve" was proposed to modify the model according to the variability and strong nonlinearity during operation of relevant thermal power units. Practice results show that the model parameters identified can meet the accuracy requirements on the model of turbine governing system in the process of power grid stability analysis.
  • Characteristic Study of a 320 MW Fully Air-cooled Generator
    Lü Meng, Zhang Peng, Liu Derong, Ning Gang
    2016, 30(4): 223-226.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the technical specifications, structural features and ventilation cooling effect of a 320 MW fully air-cooled generator in a gas-steam combined cycle unit, including the main structural parameters, material characteristics and related tests. Study results show that compared with hydrogen-cooled generator, the fully air-cooled generator has a simplified auxiliary system and facile operation, resulting in improved unit safety and efficiency.
  • Study on Heat-transfer Characteristics of Trough Solar Collectors
    Huang Xijun, Xu Jianqun, Zhang Fang, Chen Feixiang, Liu Mingtao
    2016, 30(4): 227-232.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking the trough solar collector as an object of study, a 1D steady-state model was set up according to its heat-transfer mechanism, with which factors affecting the heat loss of collector were analyzed, while the influence of inlet pressure, mass flow rate and solar irradiation on the outlet parameters was studied. The simulation results were subsequently compared with relevant literature data obtained by 3D models. Results show that the absorber emissivity is one of the crucial factors influencing the heat loss of collector. The collector efficiency increases with reducing inlet pressure, rising mass flow rate and rising solar irradiation. Although the 1D model is much simpler, its simulation result of average outlet temperature is only 0.68 K higher than the 3D model, and the average heat gain of 1D model agrees more well with experimental data.
  • Research on Structural Strength of HP Modules in High-efficient Nuclear Steam Turbines
    Deng Zhicheng, Wang Xiujin, Wang Yong, Yang Yu
    2016, 30(4): 233-236.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Technical studies were conducted on structural strength of high-pressure modules in high-efficient nuclear steam turbines, while checking calculations were performed on the temperature field and stress field of the high-pressure rotor, high-pressure valve shell and high-pressure inner casing under rated-load steady-state conditions and cold start conditions using finite element method, and for components with unaccepted strength, optimizations were carried out on their structures. Calculation results show that the structural strength of high-pressure modules in the high-efficient nuclear steam turbine has been designed up to standard through structural optimization and improvement.
  • Features of Main Feedwater Venturi Tube and its Application in Third Generation Nuclear Power Plants
    Qi Jiajie
    2016, 30(4): 237-240.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the key features of main feedwater venturi tube for nuclear power plants, and to the common methods for its calibration test, together with an analysis on problems likely to occur during operation, for which corresponding countermeasures are proposed considering the application conditions of main feedwater venturi tube in third generation passive nuclear power plants.
  • Verification Test Loop Study for Reactor Pressure Vessel Seals
    Chen Zhi, Wu Zhiying
    2016, 30(4): 241-243.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The verification test loop for reactor pressure vessel seals is designed to simulate the environment of primary loop in nuclear power plant, and realize the increase and decrease of both the temperature and pressure under high-temperature high-pressure conditions at a specified velocity. The test loop is designed to simulate actual operating conditions, requiring advanced technologies due to great difficulty in design and manufacturing. Through careful study on working principle and operation process of the verification test loop, a design plan is finally determined.
  • Effects of Low-NOx Combustion Retrofit on NOx Emission Concentration of a CFB Boiler
    Wu Jianheng
    2016, 30(4): 244-249,264.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A low-NOx combustion retrofit was conducted on a 75 t/h intermediate-temperature cyclone separation CFB boiler burning Fujian anthracite by reducing the effective area of air distributor from 13.43 m2 to 11.38 m2 and improving the secondary air ratio from 40% to 45%. The low-NOx combustion retrofit is proved to be effective by hot tests: the concentration of NOx emission is reduced from 210 mg/m3 to 180 mg/m3, satisfying the 200 mg/m3 concentration limit of NOx emission; the mechanical incomplete combustion loss q4 is reduced by 0.3%~0.6%, with reduced mass concentration of CO emission and optimized operating economy of the CFB boiler.
  • Experimental Study on SO2 Removal by Ammonia Injection into Tail Flue Duct of a 300 MW CFB Boiler
    Hou Zhifu, Gao Binbin, Gao Jianqiang, Cheng Shaowei
    2016, 30(4): 250-253.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To reduce the SO2 emission of a 300 MW CFB boiler, a SO2 removal system is designed by directly spraying ammonia into the tail flue duct, and subsequently experimental tests are conducted at the load of 260 MW on the system. Test results show that the desulfurization efficiency lies in the range of 26.4%~45.7%, which increases with the rise of ammonia flow rate. The system has a little impact on the flue gas temperature, and the maximum drop of flue gas temperature at outlet of induced draft fan is only 1.7 K. Meanwhile, the flue resistance does not change significantly at boiler tail. During the test, no obvious accumulation of fly ash or water is observed.
  • Technical Retrofit on Electrostatic Precipitator of a Power Plant for Energy Saving and Emission Reduction
    Hu Changchun
    2016, 30(4): 254-256.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The electrostatic precipitator in a power plant has long been troubled by problems such as great decrease in precipitation performance and frequent tripping of various electrostatic fields. The problems have now been solved by technical retrofit on high-frequency power source and control system of the electrostatic precipitator, with the results of reduced dust emission, lowered energy consumption, and remarkable social and economic benefits. The presentation of its operation conditions and the results of related effectiveness analysis before and after retrofit may serve as a reference for future retrofit of similar electrostatic precipitators.
  • Application of New Fluorine Plastic Condensate Filter in Dust Removal of Coal-fired Power Plants
    Jia Minghua, Jiang Haitao, Li Bin, Zhang Yubin, Zhang Yong, Fu Yuling, Wang Gang, Chu Xiaoliang
    2016, 30(4): 257-259.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The technical route of fine dust removal via vapor phase change was discussed, while the application effects and prospects of new fluorine plastic condensate filter in fine dust removal of thermal power plants were analyzed based on demonstration projects. Results show that the new fluorine plastic condensate filter has high efficiency and good application prospects in removal of fine dust.
  • Fault Analysis and Retrofit of a Circulating Water Pump for 600 MW units
    Wang Yong, Zhao Xinli
    2016, 30(4): 260-264.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The circulating water pump of a 600 MW unit has successively been troubled by major faults like shaft bending and breaking due to reasons lying in the design, installation and operation, etc., since its formal operation. Through optimal design and retrofit on the impeller and shaft, the long-standing safety problems related to the circulating water pump are solved, resulting in greatly improved safety, economical efficiency and reliability of the circulating water pump in operation.
  • Cause Analysis on Loss of Flame in a Dry-type Low-nitrogen Combustion System
    Jiang Xiao
    2016, 30(4): 265-268.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of instable flame and flame loss occurring in the dry-type low-nitrogen (DLN1.0) combustion system of a 9E gas turbine, an analysis was conducted on factors that may influence the flame from the aspect of design, installation, combustion adjustment and hardware fault, etc., based on key operation parameters on site, after which corresponding preventative and treatment measures were proposed. Operation results show that the failure of flame loss in 9E gas turbines can be effectively avoided by taking above countermeasures and the unit safety is thus guaranteed.
  • Cause Analysis and Treatment of Blade Curling Accident in a 135 MW Super-high Pressure Steam Turbine
    Zhang Jinliang, Deng Debing, Gao Kun, Wang Jiayong, Zhang Jinlin, Zhao Qingsen
    2016, 30(4): 269-273.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To clear the blade curling fault existing in a 135 MW super-high pressure steam turbine, an analysis was conducted on the damage status combined with the start-up process, which was found to be caused by the inflow of water into the steam turbine during hot start-up process. The problem was finally solved by taking appropriate measures.
  • Analysis on Main Protection Logic of a 350 MW Supercritical CFB Boiler
    Si Ruicai, Zheng Yuan, Wang Changli, Wang Mengqi, Liu Xiwen
    2016, 30(4): 274-277.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the main protection configuration of a 350 MW supercritical circulating fluidized bed (CFB) boiler, with focus on the control logic of main fuel trip and boiler trip, including a description to the investment condition in the running process. Operation results show that the unit security can be guaranteed after some improvements on the said logics, which may service as a reference for configuration of the main protection logic in similar boiler units.
  • Control Strategies for Bypass System of a 1 000 MW Double-reheat Unit and the Application
    Zhang Shiwei, Ye Luo, Xu Wei, Xu Hailei, Zhang Guoyu
    2016, 30(4): 278-281.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The 1 000 MW ultra-supercritical double-reheat unit adopts the triple-stage bypass system, and its control logic is newly developed based on traditional control strategies. The control modes and strategies respectively for the high-, medium- and low-pressure bypass system are described under startup, shutdown, normal operation and abnormal operation conditions, combined with analysis on corresponding application situation, existing problems and optimization schemes of relevant bypass systems in a certain unit during commissioning period.
  • Application of Sequence Valve Control Mode in 600 MW Supercritical Power Units
    Wang Feng, Zhong Shangwen, Lin Yizhan
    2016, 30(4): 282-284.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction was proposed to the control principles for steam distribution in mixing valve and sequence valve control mode of steam turbines. To solve the problem of large throttling loss under mixing valve control mode, flow characteristic tests were performed, based on which the steam distribution control mode was optimized. Meanwhile, reasonable operation order was proposed for the sequence valve control, with corresponding flow characteristic curves presented simultaneously. In addition, the process of valve switching was described to achieve undisturbed switching between mixing valve and sequence valve control. After application of the sequence valve control mode, the unit now runs safely and stably, resulting in reduced throttling loss and improved unit economy.
  • Fault Analysis and Troubleshooting of the Rotor in a 9E Gas Turbine Generator
    Zhang Xuelin
    2016, 30(4): 285-288.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To clear the faults occurring within 1 000 times of starts in the generator rotor of a 9E gas turbine generator set, the formation causes and common problems are analyzed, and subsequently corresponding countermeasures as well as technological and material requirements are proposed for troubleshooting of the generator rotor, which may serve as a reference for troubleshooting of similar problems.