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    Research & Analysis
  • Research & Analysis
    Application of Electrochemical Measurement in Researches
    of Boiler Flow-accelerated Corrosion
    Xu Qi, Xu Luqi, Yao Yushan, Zhang Feiran
    2015, 29(6): 385-388.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the electrochemical measurement technologies commonly used in researches of material corrosion, together with a discussion on advantages and disadvantages of the technologies adopted for study of flow-accelerated corrosion (FAC) in power plants. Analysis results show that it is convenient to use the electrochemical technologies to measure the FAC rate of metallic materials, which would be applied more in-depth on the research of boiler FAC, with further development of the theory concerning high-temperature and high-pressure hydrodynamics.
  • Research & Analysis
    Multi-model Predictive Control of Reheated Steam
    Temperature Based on Laguerre Function
    Liu Jinquan, Wang Mingchun, Tang Zhibing, Tao Chengfei
    2015, 29(6): 389-393.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of nonlinearity existing in reheated steam temperature system of thermal power plants, and to reduce the heavy computing load of traditional predictive control, a new predictive control method based on state space was proposed and applied to the reheated temperature system of a supercritical power plant, which combines the techniques of Laguerre function, state estimation and multi-model control. Simulation results show that via this method, better control quality can be obtained under either stable or variable load conditions, and simultaneously the computing load is obviously reduced.
  • Research & Analysis
    Economical Analysis on Steam Distribution Mode
    of a 600 MW Supercritical Steam Turbine
    Liu Li, Zhu Pengda, Huang Qilong, Dai Weibao
    2015, 29(6): 394-396.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Through performance test, a comparison was made to the heat rate and HP cylinder efficiency of a unit between throttle governing mode and throttle-nozzle governing mode, while an economic analysis was made under two steam distribution modes at different unit loads. Results show that with the reduction of unit load, the HP cylinder efficiency under throttle governing mode decreases sharply, which reduces gradually under the mode of throttle-nozzle governing, when the difference of heat rate becomes large between the two modes.
  • Research & Analysis
    Economic Analysis of a 1 000 MW Ultra Supercritical Unit
    with Low-temperature Economizer
    Bao Weiwei, Liu Xin, Li Jihui, Chen Peishu
    2015, 29(6): 397-401.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on analysis and calculation on thermodynamic system, detailed calculation and analysis were conducted to the design features and economic benefits of a 1 000 MW ultra-supercritical unit added with a low-temperature economizer. Results show that the heat rate of unit could be reduced by 40 kJ/(kW·h) through reasonably arranging a low-temperature economizer, indicating significant economic benefits.
  • Research & Analysis
    Analysis on Steam Turbine Operation Conditions in Gas-Steam
    Combined Cycle Co-generation Unit
    Yang Zhaohui
    2015, 29(6): 402-405.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to 5 control modes during start up of the steam turbine in a gas-steam combined cycle unit, such as the TAB control, speed control, load control, pressure control and steam compensation control, and to 4 operation conditions, like the pure condensing condition, extraction condensing condition, back pressure condition and full switching condition, as well as to the 2 control loops for switching operation. Practice indicates that these operation modes and switching/control processes are all reasonable, which have guaranteed the safe operation for both the steam turbine and the whole combined cycle unit.
  • Research & Analysis
    Automatic Turbine By-pass Control System
    in a Two-pull-One Type Gas-Steam Combined Cycle Unit
    Zhang Peng, Zhou Bin, Lü Meng
    2015, 29(6): 406-408.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the control strategy for automatic turbine bypass system of a twopullone type gassteam combined cycle unit. Practice indicates that various operation modes of the turbine bypass system have provided the power plant with great flexibility in operation.
    • Operation & Retrofit
  • Operation & Retrofit
    Pressure Compensation and Correction for Differential Pressure
    Water Level Gauge of Sub-critical Drum Boilers
    Li Xingmin
    2015, 29(6): 409-411.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To reduce the influence of boiler pressure on indicating value of the differential pressure drum level gauge in sub-critical power units, an analysis has been performed on the working principles of differential pressure water level gauges, thus obtaining the rule of violent changes in indication due to pressure fluctuation. Corresponding adjustment methods are proposed, so as to prevent any full and lack of water accidents, which is of great significance in keeping safe and stable operation of the boiler.
  • Operation & Retrofit
    Cause Analysis on Abnormal Wall Temperature Variations
    of High- and Medium-pressure Cylinder
    in a Supercritical Steam Turbine
    Li Ming, Zhou Zhiping, Fu Chenpeng, Gu Zhenyu
    2015, 29(6): 412-415.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the condition that the wall temperature of high- and medium-pressure cylinder in a supercritical 600 MW steam turbine increased and changed abnormally with the variation of load, the steam flow in cylinder interlayer has been calculated and analyzed according to test results and to the changes of thermal parameters. The cylinder is then dismantled to verify the analysis conclusions. Upon maintenance, wall temperature of the high- and medium-pressure cylinder recovers to normal.
  • Operation & Retrofit
    Primary Frequency Modulation Retrofit of
    a 9E Gas-Steam Combined Cycle Unit
    Huang Xuecheng, Li Yujie
    2015, 29(6): 416-418.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the current status that the PG9171E gas-steam combined cycle unit fails to have complete primary frequency modulation function, and to meet the requirement of power grid operation, the unit is enabled to have the primary frequency modulation function by Mark V control system configuration under full stroke load conditions.
  • Operation & Retrofit
    Analysis and Treatment on Unstable Vibration of Steam Turbines
    Gu Zhide, Feng Yaofei, Wang Hongwei, Zhang Ruishan, Li Henghai
    2015, 29(6): 419-422.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of unstable vibration existing in a 135 MW steam turbine, an analysis was conducted, after which the error was found to be caused by mass unbalance of the rotor and collision between the rotary and static parts. Stable vibration satisfying safety operation requirements of the steam turbine is now obtained, after taking following countermeasures, such as high-speed dynamic balancing of rotor, elimination of pipeline defects in the thermal system of steam turbine, etc.
    • Nuclear Technology
  • Nuclear Technology
    Analysis on Setting of Turbo-Generator Load
    Limit for Nuclear Power Stations
    Huang Meihua, Li Pingyang
    2015, 29(6): 423-427.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the reactor-turbine control logic of a CPR1000 nuclear power station, together with an analysis on possible operation risks caused by parameter mismatching between the reactor and the steam turbine. By collecting actual operation parameters of a running nuclear power station, building up mathematical model, and performing necessary calculation and fitting, a reasonable load limit is determined for turbo-generator sets, which is already applied in a nuclear power station.
  • Nuclear Technology
    Adjustment and Optimization of Seismic Bumpers in the AP1000 Integrated Head Package
    Ding Haiming, Wang Xiaomei, Huang Kaijing, Zheng Shiyou, He Jianguo
    2015, 29(6): 428-430.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the adjustment method of seismic bumpers in the AP1000 Integrated Head Package (IHP). The adjustment result is perfected via optimization of the measurement methods and improvement of the adjustment ways. Results show that the adjustment method upon optimization is able to give better play to the anti-seismic buffer.
  • Nuclear Technology
    Treatment on High Temperature of Trust Pad
    in Feed Pump Turbine of Nuclear Power Stations
    Zhang Yahui, Jia Kaili
    2015, 29(6): 431-434.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem that the temperature of thrust pad in feed pump turbine of a nuclear power station is too high, the reason has been analyzed according to the disassembly and inspection results during the overhaul of thrust pad, as well as to the parameters recorded in daily tracking. The temperature of thrust pad has finally reduced to a reasonable range through calculation, adjustment, detection with clearance gauge and other maintenance processes and methods.
  • Nuclear Technology
    Welding Consumables and Processes
    for Main Equipment of AP1000 Nuclear Island
    Yang Juwen, Li Shuangyan, Zhang Maolong
    2015, 29(6): 435-438.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    According to structural features of the AP1000 steam generator, reactor pressure vessel and pressurizer, relevant purchasing requirements of welding consumables as well as the welding processes were determined, and during the manufacture of above equipment, a number of new processes and technologies were adopted. Results show that not only the welding quality and production efficiency are improved, but also the production cost is reduced, after the adoption of the welding consumables and the application of new welding technologies.
    • Material Technology
  • Material Technology
    Properties of Austenitic Heat-resistant Steel Sanicro25
    for Ultra-supercritical Boilers
    Zhang Xian
    2015, 29(6): 439-442.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the mechanical property, creep rupture strength, anti-oxidation and anti-corrosion property, as well as to typical physical properties of the austenitic heat-resistant steel Sanicro25, which are further compared with the steels super304H and HR3C. Results show the steel can be used as the pipe of heating surfaces with steam temperature at 620 ℃ for high-efficient ultra-supercritical thermal power units.
  • Material Technology
    Failure Analysis on Weld Joint of
    T23 Heat-resistant Steels
    Li Wenbo, Shen Dingjie, Xie Yi, Hu Jiarui, Ouyang Kejian, Liu Chun
    2015, 29(6): 443-446.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Analysis was performed to the leakage at weld joint of T23 steels in service as low-temperature reheater tubes, and the reheating cracks formed at heat-affected zone of the weld were believed to be the main cause. There are two reasons leading to formation of reheating cracks: one is the stress concentration, resulted from compulsive alignment of the tubes during welding; the other is that the microstructure in heat-affected zone is coarse martensite with obvious pores, making the strength and toughness of the weld reduced, and therefore promoting the formation of reheating cracks.
  • Material Technology
    Material Quality Problems Occurring in Finishing Superheater
    Upgrading Retrofit of an Ultra-supercritical Boiler
    Lei Fangyu, Bao Ting
    2015, 29(6): 447-450.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the raw material quality problems spotted in the finishing superheater during upgrading retrofit of an ultra-supercritical boiler, like unqualified material properties and linear defects existing on surface of the steel tubes. The troubleshooting avoids the operation with defects in the finishing superheater and ensures the quality of upgrading retrofit.
  • Material Technology
    Automatic TIG Overlaying Welding Procedure
    Qualification for Valve Sealing Surfaces
    Wang Bo, Huang Guanfeng
    2015, 29(6): 451-453.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Overlaying welding was performed to inner cone of valve sealing surfaces by automatic TIG process, and subsequently different tests were performed. Results show that all the properties of deposited metal can satisfy relevant requirements, which may serve as a reference for overlaying welding of valve sealing surfaces.
    • Environmental Technology
  • Environmental Technology
    Removal Efficiency of Wet Electrostatic Precipitator
    for Inhalable Particles of Different Sizes
    Ding Chenggang, Shi Chaolin, Guo Shiyi, Jin Qiang,
    Pan Weiguo, Ding Honglei, Guo Ruitang
    2015, 29(6): 454-457.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Experimental tests were conducted to study the removal efficiency of wet electrostatic precipitator for inhalable particles. Results show that the PM2.5 removal efficiency is higher than PM10. By comparing the number concentration of particles at inlet and outlet of the precipitator, it can be seen that the smaller the particle size is, the lower the removal efficiency will be. For measurement of fine particles, it would be more accurate to perform relevant calculation according to the number concentration.
  • Environmental Technology
    Reliability Study of a Thermal Power Unit with its
    Desulfurization Bypass Flue Duct Blocked
    Zhang Haifu, Chen Zhihua, Zhang Fuzhong, Wan Taihao
    2015, 29(6): 458-462.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An assessment was made to major risks possibly existing in the desulfurization system of a power unit after its desulfurization bypass flue duct was blocked, with focus on problems concerning the 2 induced draft fans and 1 booster fan, to which RB control design was proposed for the booster fan by fully opening the moving blades as the flue gas passage after tripping of the booster fan. Results show that the method has helped to improve the reliability of relevant equipment, which may serve as a reference for similar necessary blocking of desulfurization bypass flue duct in thermal power plants.