Power Equipment

Archive

  • 2017 Volume 31 Issue 5
    Published: 15 September 2017
      
  • Select all
    |
  • Efficiency Analysis for Supercritical Carbon Dioxide Brayton Cycles
    Zheng Kaiyun
    2017, 31(5): 305-309.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking the simple supercritical carbon dioxide (S-CO2) Brayton cycle with recuperation as an object of study, the analysis method and process were presented for the cycle efficiency, while the effects of following factors on the cycle efficiency were analyzed, such as the inlet temperature and pressure of turbine, inlet temperature and pressure ratio of compressor, efficiency of turbine and compressor, effectiveness of regenerator, and the pressure loss, etc. A further study on recompression S-CO2 Brayton cycle shows that this cycle is able to solve the problem of pinch point and, as a result, it significantly improves the cycle efficiency.
  • Experimental Research on Electrical Characteristics of Fly Ash from Two Types of Furnaces
    Zhang Canqiang, Zhang Jun, Wu Haiyang, Fan Rendong
    2017, 31(5): 310-314.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Experimental studies were conducted on electrical properties of the fly ash taken from pulverized coal furnace and circulating fluidized bed boiler, respectively. Results show that temperature has a significant influence on the resistivity of fly ash, which reaches the maximum at 150℃, and decreases with the increase of voltage. The charge-to-mass ratio of fly ash firstly increases and then declines rapidly with the increase of voltage within 8~20 kV, the charged capacity enhances with increasing particle size of fly ash. The resistivity and charge-to-mass ratio of both the fly ash change with the single factor of experiment basically in similar trend.
  • Study on Subspace Predictive Control Driven by Thermal Engineering Process Data
    Jing Yajie, Zhu Xiaoliang
    2017, 31(5): 315-320.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the predictive control effect of current boiler-turbine coordinated system in coal-fired power unit, on the basis of predictive control research for multi-model subspace, the subspace method was used to obtain data directly from predictive controller. Simulation results of both the data-driven subspace predictive control and subspace-based multi-model predictive control were compared. Results show that the method proposed is feasible and effective, which may serve as a reference for further research of similar problems.
  • Performance Test and Economical Analysis of a Low-temperature Economizer in an Ultra Supercritical Coal-fired Unit
    Li Yong, Cong Xingliang, Chen Xin, Zhang Jun, Yang Jun, Chen Jian, Wu Hongtao, Xie Hong
    2017, 31(5): 321-325.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Performance test and thermal analysis were conducted to evaluate the efficiency of a low-temperature economizer in typical 660 MW ultra supercritical coal-fired unit according to ASME PTC performance test code and using equivalent enthalpy drop theory, respectively. Combined the performance test with thermal calculation based on equivalent enthalpy drop theory, the thermal performance of the low-temperature economizer can be quickly and efficiently studied under various thermal conditions, which therefore may serve as a reference for economic operation, energy-saving and optimization of the unit.
  • Discussion on Thermal Economy Calculation Methods of a Pre-dried Lignite-fired Power Generation System
    Song Kuangwei
    2017, 31(5): 326-331.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An analysis was conducted on the aspects easy to be neglected in the calculation of thermal efficiency for power plants using lignite pre-drying technology, pointing out that the energy consumed in the lignite pre-drying process is mainly transferred into heating value of the dried coal. On above basis, a corrected formula was derived for calculation of the comprehensive thermal efficiency by introducing the new concept of fuel upgrading factor.
  • Study on Adaptive Prediction Model of Boiler Oxygen Content in a 1 000 MW Unit
    Bai Yufeng, Sun Weipeng, Jiang Yong
    2017, 31(5): 332-335.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To optimize the control of boiler oxygen content, a multi-objective closed-loop optimization algorithm was proposed by developing an adaptive control system for the oxygen content under multi-coal combustion conditions through connection with the external control system, SIS system and blending combustion system. Meanwhile, a model of relative power supply cost was constructed under multi-coal conditions by building up an objective function of oxygen content optimization and setting up an analysis model of relative economy. Taking the minimum relative power supply cost as the objective function, an adaptive control strategy was designed for the oxygen content, which was proved to be effective in actual operation.
  • Influence of Supporting Slab on Heat Transfer Behavior of a Spent Fuel Transport Container during Unloading Process
    Yin Yong, Li Qipeng, Ma Qingjun
    2017, 31(5): 336-339.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Thermal analysis was conducted on the unloading and cooling process of a self-developed spent fuel transport container with supporting slab, so as to analyze the effects of the slab on heat transfer behavior of the container during unloading and cooling process. Based on models set up respectively for the container with and without supporting slab, taking one-fourth of both the simplified models as an object of study, thermal calculation was carried out using k-ε turbulent model with Fluent software. Results show that the cooling time affected by the supporting slab accounts for 20% of the total during unloading and cooling process, which can not be neglected during thermal analysis of spent fuel transport containers.
  • Harmonic Analysis and Measurement for RDPS Rectifier Circuit of the Third Generation Nuclear Power Plant
    Zhou Yunhua, Wang Shuai
    2017, 31(5): 340-343.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of inconsistent electric display between intelligent electric meter and microcomputer integrated protection device existing in three-phase half-wave rectifier loading test for RDPS of the third generation nuclear power plant, analytic research was conducted on the measurement of above two devices, during which the causes leading to the inconsistent display were found. Furthermore, Fourier expansion was used to analyze the current harmonic of the three-phase half-wave rectifier, and to derive each harmonic expression as well as the mathematical relationship between the fundamental current and the total current. The derived results were proved to agree well with actual measurements.
  • Research on Gypsum Rain Reduction of a 1 000 MW Coal-fired Plant Chimney
    Xu Jing, Duan Yufeng, Feng Yanlei, Sun Jianrong
    2017, 31(5): 344-347.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To research the formation mechanism of "gypsum rain" and eliminate the phenomenon, the volume of condensate water in wet chimney of a 1 000 MW coal-fired plant at different unit loads and environment temperatures was calculated according to the operating parameters. Results illustrate that more condensate water would be generated at higher loads and lower environment temperatures. The exhaust temperature at which vapor plume phenomenon shall not occur was also calculated when tubular GGH device is installed. Results show that the occurrence of vapor plume is significantly affected by ambient temperatures; besides GGH device, extra heat sources should be introduced to solve this problem in winter.
  • Research and Practice on Ultra Low NOx Emission of an Ultra Supercritical Coal-fired Boiler
    Hou Jianxiong, Hong Xiaofei, Liao Shining, Mao Yisheng
    2017, 31(5): 348-352.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of high NOx emission exceeding the requirements of relevant national standard, an analysis was conducted on the desulfurization system, and subsequently feasible operation measures were proposed, while related facilities were retrofitted. Results show that above equipment retrofit and operation adjustment help to reduce the NOx emission of boiler, satisfying the requirement of ultra low NOx emission.
  • Retrofit Analysis for Exhaust Mode Optimization of a Condenser Throat
    Chen Yu
    2017, 31(5): 353-355.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To reduce the exhaust pressure of a steam turbine in the retrofit project of a power plant, the energy-saving potential and economic benefit were analyzed for exhaust mode optimization of its condenser throat, based on the results of relevant thermodynamic performance tests.
  • Retrofit Schemes for the Electric Feed Pump of a 600 MW Subcritical Air-cooling Unit
    Shen Feng, Hao Fei, Tan Rui
    2017, 31(5): 356-359.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the economy of a 600 MW subcritical air-cooling unit driven by electric feed pumps, there are in total two main technical strategies. One way is to use steam feed pump instead of electric feed pump, the other is to adopt frequency conversion instead of fluid coupling. Retrofit effects of the unit at different loads were calculated respectively for both the strategies. Considering the area conditions, load rate, operation mode and investment factors, appropriate retrofit schemes were proposed for the electric feed pump in different units.
  • Design Optimization of a 1 000 MW Ultra Supercritical Double-reheat Unit
    Yan Zhe, Zhang Shiming, Gu Yong
    2017, 31(5): 360-362.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the design optimization of a 1 000 MW ultra supercritical double-reheat unit, together with an analysis on the energy-saving effect of the optimization items. The design values of auxiliary power consumption rate and power supply coal consumption have been reduced to 3.47% and 263.0 g/(kW·h) respectively, which may serve as a reference for design optimization of similar units.
  • Upgrading on the Turbine Emergency Trip System in a Thermal Power Plant
    Xing Mingcheng, Rao Feng
    2017, 31(5): 363-366.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To overcome the deficiencies of the old ETS, a retrofit scheme was proposed, which upgrades the ETS and integrates it into the DCS of the power plant. The new ETS abandons the complex electric circuit in the old system and constructs the turbine protection logic by software; the method is to connect the ETS to the network of DCS so as to realize the supervision and operation of ETS in the DCS. By proper hardware and software configuration, the new ETS can entirely meet the demand in reliability and rapidity.
  • Cause Analysis and Treatment on Abnormal Vibration of a PG9171E Gas Turbine
    Fu Zhaolong, Wan Hongjun, Jiao Peng, Zhang Yushi
    2017, 31(5): 367-370,375.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the abnormal vibration fault in a PG9171E gas turbine, which was found to be caused by the deviation of its inlet guide vane, leading to the rotating stall of partial blades in the compressor. Results show that the angular deviation of inlet guide vane has great influence on safety and stable operation of the unit.
  • Improvement on Cold End System of a 600 MW Supercritical Wet Cooling Unit
    Li Yongli
    2017, 31(5): 371-375.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To satisfy the uprating requirement of a steam turbine, an evaluation was conducted on the capacity of its cold end equipment, such as the condenser and circulating pump, etc., together with a calculation on the capacity that the cold end equipment should have after uprating of the steam turbine. On above basis, the range and key points of the retrofit as well as the selection of corresponding equipment were proposed, while a comparison was made simultaneously on economic efficiency of the unit before and after the retrofit.
  • Application of High Power Plasma Ignition Technology in Lean Coal-fired Power Plants
    Guo Bochun
    2017, 31(5): 376-378,382.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the structure of a high power plasma ignition system. To solve the problems existing in Guang'an Power Plant caused by application of the high power plasma ignition technology, improvements conducted on relevant systems. Results show that the high power plasma ignition technology can be successfully applied in high sulfur coal-fired combustion units, which may serve as a reference for further application of the technology in lean coal-fired power plants.
  • Selection of Pumping Schemes for a Gas-fired Combined Cycle Heating Unit
    Li Jianbo
    2017, 31(5): 379-382.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking the 400 MW gas-fired heat & power cogeneration project in a power plant as an example, the characteristics, application conditions, advantages and disadvantages of several common heating schemes were analyzed, after which, the cooling section extraction heating scheme was determined to be the optimum.