Power Equipment

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  • 2018 Volume 32 Issue 5
    Published: 15 September 2018
      
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  • Numerical Analysis of Flue Gas Flow Characteristics around a Heat Exchanger Based on Meshless Method
    Yan Shunlin, Wang Haoxuan, Han Wei
    2018, 32(5): 309-314.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Using meshless simulation software XFlow based on LBM, an analysis was conducted on the flow characteristics and vortex structure around a heat exchanger with the flue gas flowing at different angles. Results show that when the flue gas positively hits the heat exchanger tubes, the resistance moment is close to zero, while the turbulent transition in the wake region appears relatively late, which is favorable to the formation of uniform flow; whereas at large angles of attack, the vortex structure in the wake region develops rapidly in slantly downward direction, and a wide ranging vortex structure would form, seriously affecting the stability of the flue gas flow.
  • Optimization Study on Steam Distribution Mode of a 300 MW Heat Supply Unit
    Yang Yang, Xu Hongsheng, Guo Yixin
    2018, 32(5): 315-319.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For an N300-16.7/537/537 type heating unit, a calculation model was established based on heat balance method to study the influences of different operation modes on the heat rate. Combined with theoretical analysis and safety requirements, an optimal operation mode was determined for the heat supply unit, offering a theoretical guidance for the operation of similar heating units.
  • Research on Calculation Model for Extraction Enthalpy in Wet Steam Region of a Steam Turbine
    Zhang Yong, Jia Changsheng
    2018, 32(5): 320-323.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A calculation model was proposed for extraction enthalpy in wet steam region of a steam turbine based on stage loss theory by calculating the wet steam loss and other losses separately. The model was then used to calculate the extraction steam enthalpy of different turbines under various conditions. Result show that the calculation method has high precision and good adaptability.
  • Determination of Motion Parameters for Seismic Simulation System of the Third Generation Nuclear Power Equipment
    Ge Lei, Zheng Kaiyun, Shang Heng, Wu Zhiying, Lu Xing
    2018, 32(5): 324-327.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the seismic test requirements of the third generation nuclear power equipment, together with a description on the motion parameters of the seismic simulation system required by RIM and RRS test, and finally the motion parameters are determined for the seismic simulation system.
  • Analysis on Reliability Issues in Ground Fault Protection of Non Class 1E Low Voltage Circuit Breaker of NPPs
    Li Ye
    2018, 32(5): 328-330.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To deal with an actual false tripping of the ground fault protection system in the low voltage circuit breaker of a nuclear power plant (NPP), an analysis was conducted on the impact of multiple frequency transient components occurring at the moment of motor starts on the reliability of the ground fault protection, and finally a solution and existing problems were presented.
  • Discussion on LOCA Test Method for Nuclear Power Equipment
    Ding Duoliang, Zheng Kaiyun
    2018, 32(5): 331-334.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the fundamental requirements of LOCA test for qualification of two types of generation Ⅲ nuclear power equipment, together with a detail description to the methods of LOCA test, including the solutions to technical problems faced during LOCA test.
  • Numerical Simulation of a 220 t/h Tangentially-fired Boiler Before and After Low NOx Combustion Retrofit
    Cen Tingling, Xu Hongsheng, Zhao Longsheng
    2018, 32(5): 335-339.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Numerical simulations were conducted on the combustion condition of a 220 t/h tangentially-fired boiler before and after retrofit, while a comparative analysis was carried out on the distribution of velocity field, temperature field and component concentration in the furnace, after which, the distribution of NOx volume fraction was obtained by post-processing method. Results show that the simulated combustion condition basically agrees with the actual situation in the tangentially-fired boiler, and the error between simulation results and operating data are all within 5%; besides, the NOx volume fraction has fallen by 60% after retrofit, with improved combustion condition obtained simultaneously.
  • Effects of Post Weld Heat Treatment on Mechanical Properties of 309L Deposited Metal
    Wang Lili, Wang Peipei, Yang Juwen
    2018, 32(5): 340-343.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Mechanical properties, chemical composition and δ-ferrite number of 309L deposited metal were respectively tested, analyzed and determined under different post weld heat treatment conditions, so as to obtain the effects of different post weld heat treatment conditions on the mechanical properties of the deposited metal. Results show that, with the increase of heat treatment holding time, the percentage elongation after fracture decreases whereas the tensile strength increases, which may serve as a reference for design, procurement and acceptance of 309L welding materials.
  • Discussion on Energy Saving Technology of Clean Energy Absorption
    Zhuang Jianhua
    2018, 32(5): 344-347.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For energy saving purposes, a retrofit scheme was proposed for the two ways of wind power absorption in north China in winter, by adopting peaking strategy at different degrees for different forms of power generation, according to the thermal economy analysis method of thermal power plant. Results show that, on the side of power plant, for pure condensing units, deep peaking should be taken at first, while for heat and power cogeneration units, an accumulator tank should be added, so as to make way for wind power absorption; whereas on the side of user, heating boilers should be transformed into electric boilers, to leave space for wind power consumption.
  • Techno-Economic Analysis on Primary Frequency Regulation Technologies of a 1 000 MW Ultra Supercritical Unit
    Bao Weiwei, Cao Ruifeng, Duan Jinpeng, Yu Haipeng
    2018, 32(5): 348-352,356.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the techno-economic performance of a 1 000 MW ultra supercritical unit with primary frequency regulation, an analysis was conducted on the working principle, frequency regulation characteristics and thermal economy of the following three main technologies:control valve pre-throttle technology, adjustable regenerative extraction technology and condensed water throttle control technology. Results show that the condensed water throttle control technology is the most economical one, followed by the adjustable regenerative extraction technology, and the control valve pre-throttle technology. Compared with the control valve pre-throttle technology, the unit heat consumption could be reduced by 22 kJ/(kW·h) when the condensed water throttle control technology is used.
  • Fault Analysis and Disposal of a 255 MW Gas-Steam Combined Cycle Unit through Shaft Seal Clearance Measurement
    Sang Quanwei, Liu Zhenxiang, Tian Xinqi, Ren Wei
    2018, 32(5): 353-356.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of too small shaft seal clearance existing in the No.2 turbine of a 2×255 MW gas-steam unit, caused by a certain degree of foundation sinking and differential settlement in the bearing block, found by measuring relevant elevations, corresponding adjustment measures were proposed, such as appropriately increasing the upper clearance of shaft seal in the low-pressure cylinder, etc. This may serve as a reference for installation of new gas-steam combined cycle units.
  • Energy Saving Optimization Analysis of the Pulverizing System in a 660 MW Ultra Supercritical Unit
    Huang Jing, Jiang Bo, Shi Mengmeng, Xiong Zhong
    2018, 32(5): 357-360.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a 660 MW ultra supercritical coal-fired power generation unit as an object of study, improvement schemes were taken for the pulverizing system by lowering the hydraulic pressure, and optimizing the combination of the three coal mills during low load operation, etc., following which, the technical index of unit is significantly optimized, resulting in reduced net coal consumption, increased generating efficiency, and lowered generating cost.
  • Analysis and Improvement on the Overspeed Protection System of a 1 000 MW Steam Turbine Unit
    Wu Gongbao, Wu Zhenqing
    2018, 32(5): 361-365.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the design schemes for control system configuration and mechanical overspeed protection of a 1 000 MW steam turbine unit, an analysis was conducted on the necessity and feasibility of the improvement to the overspeed control system, while a description was made to an actual application status, which may serve as a reference for optimization of overspeed protection system of similar steam turbine units.
  • Cause Analysis and Countermeasures for Early MGGH Failures in a Power Plant
    Yan Xiaohua, Bao Ting
    2018, 32(5): 366-369.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To find the causes leading to frequent leakages in a gas cooler during operation of the power plant half a year later after the retrofit for ultra low emission of flue gas pollutants, the leakage samples were tested and analyzed from the aspects of flue gas flow field and operation conditions, etc. Results show that the leakages are caused by fly ash abrasion due to design faults in the diversion vane, to which, corresponding countermeasures are put forward.
  • Retrofit of a 300 MW Pulverized Coal-fired Boiler for Flue Gas Waste Heat Recovery
    Wang Shuai
    2018, 32(5): 370-373.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the efficiency of a 300 MW pulverized coal-fired boiler, 2 schemes were proposed for flue gas waste heat recovery, while the economy of the unit and the stability of equipment operation were compared and analyzed for both the schemes. Results indicate that the coal consumption in scheme 1 and scheme 2 could be reduced respectively by 1.8 g/(kW·h) and 3.5 g/(kW·h), with an annual revenue of 1.872 million RMB and 3.64 million RMB accordingly; besides, the temperature of the flue gas passing through the low-temperature economizer and air preheater in scheme 2 is higher than in scheme 1, indicating better performance of scheme 2 in inhibiting low-temperature corrosion, which therefore is recommended as the optimal scheme.
  • Performance Parameters Upgrading of a 600 MW Supercritical Steam Turbine Unit
    Chen Xianhui, Deng Yu, Lei Xiaolong, Zhang Xiaobo
    2018, 32(5): 374-378.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the economic performance of a licensed 600 MW supercritical steam turbine unit, a retrofit was conducted for the turbine based on the third-generation high-efficiency flow technology of impulse steam turbine, during which, following measures were taken, such as upgrading the main steam parameters, optimizing the inlet and outlet flow passage as well as improving the structure of steam seal, etc. Results of thermodynamic performance tests show that both the efficiency and the heat rate of the retrofitted steam turbine are better than the original design values, achieving the domestic advanced level.
  • Cause Analysis and Treatment on Axial Rubbing Fault between Rotor and Stator in LP Cylinder of a 1 000 MW Steam Turbine
    Zhang Shiwei, Xu Jianqun
    2018, 32(5): 379-382.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To deal with the axial rubbing fault occurring between stator and rotor of a 1 000 MW steam turbine unit, a wear analysis was conducted by taking samples from relevant rubbing areas on outlet side of the LP rotor at governing end, based on differential expansion conical surface measurement method, after which corresponding countermeasures were put forward and taken. Results show that the measures proposed are proved to be effective, which have broad prospects in engineering applications.