Power Equipment

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  • 2016 Volume 30 Issue 1
    Published: 15 January 2016
      
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  • Effects of Operating Data on SCR Inlet Parameters and Boiler Efficiency under Low Load Conditions
    Chen Jingwei, Wei Hongqi, Zhong Yafei
    2016, 30(1): 1-6.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a 660 MW supercritical unit as an object of study, the effects of operation parameters on following factors were studied through massive tests and DCS data, such as the NOx emission, boiler heat economy and the operation reliability of SCR system, etc. Test results indicate that the heat ecnonomy of boiler improves at the cost of environmetnal performance; the effects on SCR relaiblity vary with the adjustments to different operation parameters, and in actual operation, the effects of various operating parameters on the boiler should be considered under the premise keeping the balance between environmental protection and heat efficinecy.
  • Analysis on Fouling Characteristics of Xinjiang High-alkali Coal
    Ma Dafu, He Xiang, Zhou Wentai, Wei Zengtao, Cao Jianwen
    2016, 30(1): 7-10.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An analysis was conducted to the action mechanism of mechanical and viscous force during formation process of fouling, slagging and corrosion when burning high-alkali coal. Results show that fouling faults are not easy to occur under oxidization atmosphere due to higher fusion temperature of ash; the fouling degree would be relatively low in the case of lower temperature in the tail flue gas duct of boiler and higher flue gas velocity.
  • Economic Analysis on Additional Steam Control Technology for a 1000 MW Ultra Supercritical Unit
    Bao Weiwei, Gao Min, Pang Haocheng, Shen Weiguo
    2016, 30(1): 11-15.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the analytical calculation method for thermal system, detail calculation and analysis were conducted to the economy and design of a 1000 MW ultra supercritical unit with additional steam control technology. Results show that after application of this technology, the pressure of main steam can reach the rated value and the unit heat consumption has been reduced by 26 kJ/(kW·h), indicating obvious economy benefit.
  • An Optimized Boiler Combustion System Based on LSSVM and Online Parameter Optimization
    Tao Chengfei, Wang Mingchun, Tang Zhibing, Liu Jinquan
    2016, 30(1): 16-20.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The basic concept of least squares support vector machine (LSSVM) is introduced, and the model and procedures for online optimization of boiler combustion parameters are proposed, which is calibrated using hot-state experimental data of a boiler. Results indicate that the boiler combustion model established based on online parameter optimization and LSSVM is able to trace the time-variant characteristics of the boiler combustion system, with good generalization ability and high calculation speed.
  • Effects of Deep Participation in Peak Regulation on the Coal-fired Boiler of a Supercritical High-capacity Thermal Power Unit
    Shen Li, Xu Shude, Guan Jian, Lu Hongyue, Qiu Lichun
    2016, 30(1): 21-23.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In the light ofactual situation that supercritical power units have to take part in peak regulation, influence factors on the coal-fired boiler are analyzed from the aspects of security, economy and environmental protection during deep participating in peak regulation of the unit, to which countermeasures are put forward for possible problems. Practices indicate that the peak regulation requirements can be satisfied only after following problems are comprehensively considered, such as the boiler's low-load combustion stability, hydrodynamic stability, prevention of tube wall overheating and corrosion of tail heating surfaces, etc.
  • Calibration of Fan Vibration Monitors
    Hu Haijun
    2016, 30(1): 24-27.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An analysis is presented to the calculation way of vibration monitoring instrument, including specific descriptions to the calibration method for relevant vibration transducers, vibration monitors and monitoring loops, while the main criteria for error analysis and calibration judgment are proposed.
  • Study on High-temperature Yield Strength Fluctuation of the S30432 Steel
    Wang Zheng, Wang Miaomiao, Cui Zhengqiang
    2016, 30(1): 28-30.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    High-temperature tensile tests were conducted to S30432 steel tubes made by different manufacturers, while the microstructures of corresponding tensile fracture surfaces were analyzed. Results show that the yield strength of S30432 steel fluctuates in the temperature range of 600-700℃, and its high-temperature tensile strength increases with the rise of temperature. Through microstructure analysis, the reason why the yield strength of S30432 steel at 700℃ is slightly higher than at 650℃ is found to be caused by much dispersion strengthening phases precipitated at 700℃, which inhibit the movement of dislocations.
  • Assessment Matrixes Development of COSINE Best-estimate LB-LOCA Evaluation Model
    Fu Xiaoliang, Liu Lifang, Yu Nan, Du Zheng, He Siqi, Dong Bo, Liang Guoxing, Yang Yanhua
    2016, 30(1): 31-34.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Major phenomena and processes in different stages of large break loss of coolant accident (LB-LOCA) in pressurized water reactor are identified and ranked according to the latest EMDAP method proposed by NRC, based on which three assessment matrixes for best-estimate evaluation models corresponding to the propagation stages of LB-LOCA are developed in combination with analysis on existing experimental data.
  • Numerical Simulation and Technological Measures for Welding of Divider Plates
    Sun Guohui, Zhang Lide
    2016, 30(1): 35-39.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A three-dimensional model was established according to the actual size of a steam generator, and a numerical model was built up for the welding process according to the material properties and welding process to simulate the state of stress during welding. Numerical simulation results indicate that the residual stress peak is located at the weld toe of divider plates, of which the value exceeds the yield limit of the nickel-based substrate. Based on the simulation results and considering specific features of various welding joints at different locations of divider plate, corresponding welding process and measures are adopted, so as to reduce both the residual stress and the cracking risk in relevant welding area during manufacturing and operation of the equipment.
  • Analysis on Intergranular Corrosion of 304H Austenitic Stainless Steel for Gen-Ⅲ Reactor Vessel Internals
    Shen Jie, Li Yanbao
    2016, 30(1): 40-42,53.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the difference of main materials for the reactor vessel internals of Gen-II+ and Gen-Ⅲ, with focus on analyzing the property of 304H stainless steel against intergranular corrosion during actual manufacturing process for the Gen-Ⅲ nuclear power station, thus presenting suggestions for rational application of 304H stainless steel in Gen-Ⅲ reactor vessel internals.
  • Signature of Eddy Current Indications at U-tube Bend Areas of AP1000/CAP1400 Steam Generators
    Wang Weichao, Cao Gang, Guo Yun
    2016, 30(1): 43-45,53.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By analyzing the bending technology and wall deformation characteristics of heat-transfer tubes in a steam generator, the signature of similar eddy current indications was studied, so as to find an appropriate method for analysis on signals detected from this region.
  • Defect Analysis and Improvement of a DRPI Detector
    Ling Qi, Yang Haibo
    2016, 30(1): 46-49.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By analyzing the problems found in the digital rod position indication (DRPI) detector of an AP1000 self-reliance supporting project, corresponding improvement measures were proposed to the manufacturing procedure of DRPI detector, while quality control and acceptance inspection were conducted on related key processes using relevant standards. Results show that above defects can be eliminated without reoccurrence through improvement on manufacturing procedure and application of relevant standards, which may serve as a reference for subsequent manufacturing and quality control of similar facilities.
  • Retrofit on Insufficient Temperature of a 1075 t/h Boiler Reheater
    Shen Haihua
    2016, 30(1): 50-53.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of insufficient outlet steam temperature of a reheater resulted from lowered inlet steam temperature after flow path reconstruction of a 1075 t/h boiler, a special three-way structure is adopted to expand the capacity and area of heating surfaces in the medium- and high-temperature reheater, so as to improve the outlet steam temperature up to the design value, under the premise that the general arrangement and structure of the original reheater are not changed, the flow distribution in heating surfaces is guaranteed, and the wall temperature is kept under the allowable limit.
  • Cause Analysis on Sudden Change of Temperature Difference between Upper and Lower Casing of HP Cylinder in a 158 Type Turbine
    Yang Fan, Ding Yongneng
    2016, 30(1): 54-57.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    After normal shutdown of a 9FA gas-steam combined cycle unit for several hours, the temperature difference between upper and lower casing of its high-pressure cylinder in the 158 type turbine changes violently, resulting in startup termination of the unit in purging stage due to shaft vibration. The causes are finally found through analysis and calculation on the temperature distribution at different areas of the high-pressure main steam pipe.
  • Discussion on the Key Operating Parameters of an MPS Medium-Speed Mill for Grinding Lignite
    Huang Yong, Wang Chunmin
    2016, 30(1): 58-60,67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The mode and operating difficulty of an MPS medium-speed mill for grinding lignite have been studied, while conditions under which normal operation of the mill can be kept are analyzed based on project examples, and subsequently suggestions on selection of some important operating parameters are proposed, including the moisture of pulverized coal, primary air ratio, primary air temperature, outlet temperature of mill and pulverized coal fineness, etc. Practices indicate a medium-speed coal mill can be adopted directly for raw coal with moisture content of less than 35%, which can be conditionally adopted through parameter adjustments for raw coal with moisture content of 35% to 40%, while a drying system needs to be added extraordinarily when the moisture content is greater than 40%.
  • Soft Sensing of Flue Gas Moisture Content in Thermal Power Plant
    Chen Yongcheng
    2016, 30(1): 61-63,67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A method for soft sensing of flue gas moisture content was proposed according to basic thermodynamic principles, so as to study the variation law of flue gas moisture in different desulfurization stages using limestone-gypsum wet process. Practices indicate that the method has the advantages of accurate measurement and good stability in comparison with traditional dry and wet oxygen method and capacitance method, which therefore may serve as a reference for comparison with currently used methods.
  • Installation of Supporting Truss for Bottom Penthouse of a W-flame Boiler
    Yuan Shengbo, Jiang Zhiqi
    2016, 30(1): 64-67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the installation of supporting truss for bottom penthouse located in arched area of a W-flame boiler, together with an analysis on the difficulties during installation, to which several hoisting schemes are proposed for vertical trusses that have direct influence on the water wall erection. By comparing the advantages and disadvantages of above schemes, it is pointed that small hoisting mechanisms are suitable for installation of similar trusses.
  • Shortcomings Existing in Emergency Protection Module of 9E Gas Turbine's Mark Ⅵe Control System and the Countermeasures
    Li Yujie, Huang Xuecheng
    2016, 30(1): 68-70.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the emergency protection configuration in MarkⅥe control system of 9E gas turbines, together with an analysis on the shortcomings. Through optimization on the emergency protection configuration, the risk of malfunction of emergency protection can be reduced, so as to improve the stability of unit operation.