Power Equipment

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  • 2015 Volume 29 Issue 2
    Published: 15 March 2015
      
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  • Wet Air Enthalpy Calculation Model and its Application
    Zhang Guangyuan, Shen Qiunong
    2015, 29(2): 83.
    Abstract ( )   Knowledge map   Save
    A calculation model for thermophysical properties of wet air working medium was set up with Matlab using the wet air model based on RK state equation for real gas mixtures (called RK model), which was then compared with the calculation model for ideal gas. Both the models were used to calculate the outlet parameters of a saturator with given parameters. Results show that the calculation data of above two models agree well with one another at low parameters.
  • Integration Research and Overall Performance Analysisof IGCC Thermodynamic System with F Class Gas Turbine
    Gu Huanian, Zhu Zhijie
    2015, 29(2): 87.
    Abstract ( )   Knowledge map   Save
    Based on the development tendency of IGCC technology, different types of IGCC systems with F class gas turbine were studied and simulated, during which the overall performance parameters were obtained while their thermal performance was compared among different types of system schemes. Study results show that the net output of F class IGCC system is within 350~450 MW, and its net efficiency is around 38% under wet gasification with quenching process, which is around 48% under dry gasification with sensible heat recovery process. IGCC system with CO2 capture process accords with the trend of low carbon economy, but the thermal performance declines dramatically after the integration of capture device, and for F class IGCC system, the degree of decline is up to 8 percent. The thermal performance of F class IGCC system with twopullone combined cycle is better than the onepullone type, and the twopullone type IGCC is beneficial to the reduction of unit cost, conforming to the development direction of large scale IGCC systems.
  • Analysis on Service Life Loss of Steam Pipes Causedby Abnormal Temperature Fluctuations
    Kang Chaoyang, Mao Hefang, Chen Wei
    2015, 29(2): 93.
    Abstract ( )   Knowledge map   Save
    By theoretical analysis on the mechanism of abnormal temperature fluctuations in steam pipe, the sharp temperature fall is found to be caused by heat exchange between the steam in pipe and the water on pipe wall. With the aid of software ANSYS, researches were conducted to the straight pipe and elbow where sharp temperature fall occurred, such as temperature field analysis, thermal stress analysis and internal pressure stress analysis, based on which calculations were carried out to the temperature difference between inner and outer surface of the pipe as well as to the stress changes. Comparison results between above calculations and ASME codes show that the maximum life loss rate of the straight pipe and elbow are respectively 0.020% and 0.019%.
  • Study on Optimal Cost Model of Power Plant Fuel
    Wang Junfeng, Hao Runtian
    2015, 29(2): 96.
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    The cost structure and feature of a power plant are analyzed, which shows that the fuel cost control is essential to the overall cost control of the power plant. Considering the constituent elements of power plant fuel cost, a modeling idea of optimal fuel cost was proposed, including establishing a power supply coal consumption model based on calorific value of asfired coal and a unit price model of standard coal. Optimal calorific value of asfired coal was obtained using balance algorithm. Taking the minimum fuel coal as an objective function, and the optimal calorific value of asfired coal as restraint conditions, an optimal fuel purchase model was set up. Comparison test results prove the method to be effective, which may serve as a reference for fuel purchase in power plant, thus reducing the fuel cost and improving the economical benefits.
  • Discussion on Simplified Calculation Formula of Turbine Reaction Changes
    Huang Ruguang, Li Xia, Xiang Molin
    2015, 29(2): 102.
    Abstract ( )   Knowledge map   Save
    The  simplified calculation formula for reaction changes of steam turbine under offdesign conditions was studied, following which a new simplified calculation formula suitable for a large range of reaction degree was derived. The new formula’s coefficient can be determined by the stage’s structural parameters, indicating a clear physical meaning. Calculation results of the new formula are supported by relevant tests, which therefore may serve as a reference for offdesign performance analysis of steam turbines.
  • Design Features of Coordinated Control Systemin a 1000MW Ultra Supercritical Unit
    Tao Chengfei, Wang Mingchun, Tang Zhibing, Liu Jinquan
    2015, 29(2): 106.
    Abstract ( )   Knowledge map   Save
    An introduction is being presented to the features of coordinated control system (CCS) in a 1 000 MW ultra supercritical unit, together with an explanation to its structure, system and actual operation, etc. Preventive measures are put forward for relevant problems that may occur during its operation, which may serve as a reference for design of similar units.
  • Study on Deaerator Exhaust Steam Recovery Technology
    Song Hui, Zhuang Jianhua, Tan Xiu
    2015, 29(2): 109.
    Abstract ( )   Knowledge map   Save
    Based on equivalent enthalpy drop theory, a comparison was made between two recovery schemes of exhaust steam from the perspective of safety and economy consideration  one is to recover the deaerator exhaust steam directly into shaft seal heater, another is to recover the steam into gland seal heater via exhaust steam recovery device. Results show that over 99% exhaust steam can be recovered by the latter scheme, i.e. to recover the steam into gland seal heater via steam recovery device, which helps to eliminate noise pollution caused by deaerator exhaust steam.
  • System Optimization to Prevent Turbine Bearing Burnout due to Lack of Lubricating Oil
    Jia Jie
    2015, 29(2): 113.
    Abstract ( )   Knowledge map   Save
    To prevent turbine bearing burnout failure caused by lack of lubricating oil, a number of optimization measures are proposed for the control system based on actual examples, with further discussion performed on advanced design ideas and principles for control system of largescale equipment including steam turbine. Also the difference in design ideas is analyzed between capital construction phase and production phase of general power plants. This may serve as a reference for control system optimization of other newly established power plants or the power plants that have already put into operation.
  • Application of Electromagnetic Isolation of Local Instruments in Power Plant
    Lu Wenhua, Cheng Weiguo, Chen Haibing, Qian Anjia
    2015, 29(2): 116.
    Abstract ( )   Knowledge map   Save
    Local instruments in thermal power plant are generally disturbed by electromagnetic waves emitted by communication devices such as field intercoms and mobile phones, etc., which may lead to indicating deviation of the monitoring & control instruments, in some cases may even cause accidents of false tripping. By analyzing the category of electromagnetic waves, different shielding and isolating measures are proposed, so as to eliminate the interference of electromagnetic waves on relevant local instruments.
  • Cause Analysis of Hanger Tube Burst in a Boiler
    Mao Shiyong, Zhang Xuexing, Dong Meng, Xie Xiaoyuan
    2015, 29(2): 120.
    Abstract ( )   Knowledge map   Save
    To solve the problem of frequent hanger tube burst occurring in short operation period of a 660 MW subcritical boiler, a number of experimental tests were conducted in consideration of the boiler structure, such as the macroscopic examination, metallographic test and composition analysis, etc. Results show that the hanger tube bust is directly caused by the accumulation of NaFePO4 and Na3PO4 salt on inner surface of the tube, where local longtime overheating happens.
  • Tube Burst Analysis for Highpressure Superheaterin HRSG of PG9171E Gas Turbines
    Ren Qiang, Ji Baoping
    2015, 29(2): 125.
    Abstract ( )   Knowledge map   Save
    During early operation stage of the heat recovery steam generator (HRSG) matching PG9171E gas turbines, tube burst failures were frequently encountered in the hightemperature section of its highpressure superheater, which seriously affected the safety of unit operation. Detail analysis was conducted to the causes of tube burst from the aspects of welding, attemperating water and structure, etc., after which the failures were found to be caused by poor welding quality, inappropriate attemperating water flow and unreasonable structure of the tube banks. Improvement measures were taken to the unit, such as adding reinforcement elbow and strengthening the control of welding quality. Retrofit results prove above measures to be effective, by which safety operation of the unit is achieved.
  • Fault Analysis and Technical Measures for I&C System ofa 9FA Singleshaft Combined Cycle Unit
    Pang Jingfang
    2015, 29(2): 129.
    Abstract ( )   Knowledge map   Save
     An introduction is being presented to the analysis and treatment process of three abnormal faults occurring in the operation of a GE S109FA gassteam combined cycle unit, such as the controller failure, the abnormal stroke of antisurge valve and the ignition deflagration, etc., together with some preventive measures proposed for above faults, which may serve as a reference for maintenance of similar units.
  • Cause Analysis and Countermeasures for BottomAsh Artesian Flow in CFB Boilers
    Liang Jianhong
    2015, 29(2): 133.
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    Due to inappropriate coal fineness and unreasonable operational parameters, bottom ash artesian flow is frequently encountered in the cooler of circulating fluidized bed (CFB) boilers, which seriously affects the safety and steady operation of the unit. By conducting simulation tests on relevant factors that contribute to the bottom ash artesian flow, corresponding countermeasures are proposed and taken, after which significant effects are obtained for several boilers.
  • Analysis on Thermal Performance of a 135MWSinglecylinder Steam Turbine
    Liu Li, Liu Zhongxuan, Dai Weibao, Huang Qilong
    2015, 29(2): 136.
    Abstract ( )   Knowledge map   Save
    An introduction is being presented to the unit configuration, flow characteristics and thermal performance of a 135 MW singlecylinder, singleshaft and singleflow steam turbine. The blades adopt 3D aerodynamic design, and the cascade is of the meridian shrink type in the governing stage, which helps to reduce the second flow loss and increase the flow efficiency. Performance test results show that the efficiency of highpressure cylinder can reach 8157%, higher than the design value.
  • Application of INFIT Control System in Guodian Zhishen EDPFNT+ System
    Tang Wei, Zheng Zhigang
    2015, 29(2): 139.
    Abstract ( )   Knowledge map   Save
    An introduction is being presented to the application effect of INFIT control system in Guodian Zhishen EDPFNT+ system, and to the problems found during implementation and the solutions taken for above problems, together with an analysis performed on application feasibility of the technology. The practice shows that, after adopting INFIT control system, the coal category adaptability of unit is enhanced, the control quality and stability are improved, and the energysaving effect is greatly increased.
  • Screening Scheme for Tube Preblocking of MSR and its Application
    Ji Runjing
    2015, 29(2): 142.
    Abstract ( )   Knowledge map   Save
    To deal with the quality accident occurring in the MSR of a nuclear power plant, potential risk analysis was carried out, so as to determine the damage extent and scope of relevant facilities, and subsequently work out the screening scheme for tube preblocking of the MSR. The quality of relevant facilities was finally guaranteed within the allowable tube blocking margin. Practice shows that above risk analysis, damage evaluation and screening scheme for tube preblocking of Utype tube reheater may serve as a reference for treatment of similar problems.
  • Pump Shaft Reverse Rotation Detection and the Sensor Arrangement
    Su Guoquan
    2015, 29(2): 146.
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    To satisfy the requirement that the reverse rotation status of pump shaft must be monitored, some theories and methods are analyzed concerning reverse rotation monitoring, with focus on the installation angle of relevant sensors under different conditions. It is concluded that different installation methods may be adopted for the sensor, such as by single keyway, dual keyways or by a disc with 8 teeth, in which cases reliable operation can be obtained.
  • Modeling and Simulation of Matlabbased Emergency Diesel Generator Set in Nuclear Power Plant
    Zhang Dongfu, Cui Jianhua
    2015, 29(2): 149.
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    When a nuclear plant loses its normal power supply, the diesel generator set should be able to start up and carry load within specified duration according to the loading sequence. A simulation model of the emergency diesel generator set was established based on Matlab/Simulink, with which the startup and loading process were simulated for the diesel generator set driving an asynchronous motor, while its dynamic characteristic curve was given. Simulation results show that the model is able to accurately reflect the mechanical and electromagnetic coupling process of the diesel generator set, which therefore may serve as a reference for capacity determination of similar emergency diesel generator sets.