Power Equipment

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  • 2015 Volume 29 Issue 5
    Published: 15 September 2015
      
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  • Combined Numerical Simulation on Coupled Fluid Flow between Exhaust Hood and Laststage Blades
    Li Yong
    2015, 29(5): 311.
    Abstract ( )   Knowledge map   Save
    A combined numerical simulation was conducted to coupled fluid flow between exhaust hood and laststage blades of a steam turbine using CFD software CFX. Compared with single simulation of fluid flow in exhaust hood, the combined simulation takes consideration of the strong flow interactions between exhaust hood and laststage blades. For modeling of the cascade flow passage in combined simulation, either single passage or whole annular cascade can be adopted, and the combined simulation based on whole annular cascade can reduce the error of parameter transmitting from one side to the other of periodic interface, which therefore is able to simulate actual inlet conditions and obtain accurate flow field in the exhaust hood, so as to improve the evaluation accuracy on aerodynamic performance of the exhaust hood.
  • Dynamic Stiffness Correction of Bearing Pedestals in Halfspeed Nuclear Power Units
    Jiang Jun
    2015, 29(5): 316.
    Abstract ( )   Knowledge map   Save
    Based on 3D finite element method and taking the halfspeed nuclear power unit as a prototype, the relationship was analyzed between real dynamic stiffness of bearing pedestal (at bushing bottom) and the dynamic stiffness of top head flange. FEA results show that within 0〖KG-0.4mm〗〖CD*5/9〗〖KG0.7mm〗25 Hz, there is a simple proportional relationship between above two kinds of dynamic stiffness, therefore the real dynamic stiffness of bearing pedestal can be deduced according to actual measurements of the top head flange.
  • Application of Doublepipe Technology in Largeoutput Longdistance Pneumatic Conveying Systems
    Ma Feiyu, Li Zijia, Wang Wei
    2015, 29(5): 320.
    Abstract ( )   Knowledge map   Save
    The doublepipe structure was proposed for dust removal system of large coalfired power units with features of large output and long distance, to which the conveying mechanism was studied using numerical simulation of hydrodynamics. According to the features of large output and long distance, relevant parameters were optimized, such as the openhole spacing of internal pipe, the diameter ratio of internal to external pipe, and the opening size on orifice plate, etc. Results show that the optimization of doublepipe structure can help to meet the requirements of dust pneumatic conveying, although the doublepipe is featured by low gas velocity, high concentration and strong gassolid mutual interference.
  • Operation Optimization of the Pulverizing Systemin Large Thermal Power Units
    Li Jing, Liang Xuedong, Sun Zhong, Zhao Ming, Qiu Yalin, Xiang Wenguo
    2015, 29(5): 326.
    Abstract ( )   Knowledge map   Save
    By analyzing the operation data of a 1 000 MW thermal power unit, the feeding quantity of each coal mill was found to be fluctuating widely at the same generation load, indicating that the load distribution among various mills would affect the operation efficiency of the power unit. To optimize the output of each mill, corresponding countermeasures were proposed for optimization of the pulverizing system, to which validation experiments were conducted. Results show that the boiler efficiency can be increased when the unit load is in 700〖KG-0.4mm〗〖CD*5/9〗〖KG0.8mm〗900 MW after optimization of the mill load distribution.
  • Application of Fuzzy PID in Main Steam TemperatureControl of the Power Unit
    Zhuang Wei, Xiao Bole, Gao Sheng, Zhang Qiang
    2015, 29(5): 331.
    Abstract ( )   Knowledge map   Save
    To solve the problems that a large number of disturbances exist in the main steam temperature control system of a power plant with poor antijamming capability, a fuzzy link was added to the control system, thus forming the FuzzyPI controller, of which the control effects were compared with that of the conventional PID. Simulation results show that the FuzzyPI controller has better control effects over conventional PID in following important indicators, such as the response time, overshoot and so on.
  • Analysis on Protection Function in Control Systemof SGT5-4000F Gas Turbines
    Zou Baochan
    2015, 29(5): 336.
    Abstract ( )   Knowledge map   Save
    Protection functions in SGT54000F gasturbine control system are introduced, which are realized in different ways. To analyze the key items in the protection functions, a comparison is conducted among the distributed control system, high speed controller FM458, hardware circuit SCHLOESSOR and the sequence control system. By the way, the test methods are explained for each part of the protection functions, as well as the do's and don'ts.
  • Study on Automatic Control for Parallel Operation  of Axial Flow Fans in Thermal Power Units
    Ma Tianting, Hu Yiqun
    2015, 29(5): 340.
    Abstract ( )   Knowledge map   Save
    An analysis was conducted to following unusual conditions occurring in parallel operation of axial flow fans, such as disturbance, stall, surge and blower pinch, etc., based on which automatic control strategies were put forward for the adaptive rate rotor (stator) blade balance circuit, automatic gain adjustment circuit, load balance circuit and override lockup circuit. Results show that by optimizing the conventional control system of above axial fans, automatic controls can be achieved in the process of fan joining, quitting and parallel operation, thus obtaining enhanced safety of fan operation.
  • Shafting Vibration Modal Test for Large TurboGenerator Sets
    Xing Min
    2015, 29(5): 345.
    Abstract ( )   Knowledge map   Save
    To provide electromagnetic vibration exciter with adequate dynamic torque for rotary machinery, an electromagnetic vibration exciting system was developed for modal test of rotor system in large turbogenerator sets. Application results show that the system is compact and removable, with which modal tests could be performed on site in an automatic manner.
  • Thermal Economy Analysis of a 1000 MW Ultra SupercriticalUnit with External Steam Cooler
    Bao Weiwei, Yu Haipeng, Liu Shiyun, Duan Jinpeng, Ren Xiangning
    2015, 29(5): 348.
    Abstract ( )   Knowledge map   Save
    By thermaldynamic calculation analysis, the economy of a 1000 MW ultra supercritical power unit with external steam cooler was calculated. Results show that by adding an external steam cooler to the highpressure heater in singlestage series arrangement, the unit heat rate can be reduced by 14.5 kJ/(kW·h), indicating obvious economy of the unit.
  • Steam Source Optimization for Soot Blowing Systemof 600 MW Subcritical Power Units
    Huang Xiangbin
    2015, 29(5): 353.
    Abstract ( )   Knowledge map   Save
    The steam source optimization scheme was proposed by adopting lowgrade steam at inlet of panel reheater instead of highgrade superheated steam for the purpose of soot blowing, which was applied to 2×600 MW subcritical power units. The soot blowing system is able to work safely and reliably after optimization retrofit, while the unit operation economy is improved simultaneously.
  • Energysaving Optimization of a 330MW CFB Boilerduring Cold Start Process
    Wu Haisu, Xu Liwei
    2015, 29(5): 356.
    Abstract ( )   Knowledge map   Save
    For the course of a 330 MW CFB boiler from cold start ignition to continuous coal input, factors influencing the startup time and the oil consumption were analyzed, to which optimization adjustment was made. Results show that after optimization, the initial bed temperature is increased by 41K, the startup time is reduced by 84minutes and the oil consumption is decreased by 6.4 t, indicating remarkable optimization effects.
  • Variable Frequency Retrofit of a Boostup Fanand the Energysaving Analysis
    Tang Zhongshun
    2015, 29(5): 360.
    Abstract ( )   Knowledge map   Save
    Variable frequency retrofit has been conducted to a boiler boostup fan, which is of the stationary blade adjustable axialflow type, and has high throttling loss and high house power consumption during low load operation. An introduction is presented to the retrofit scheme and the unit economy after retrofit, while comparative analysis and calculation are performed to the motor power consumption under same load conditions before and after retrofit. Retrofit results show that the annual rotor power consumption may be reduced by 400.312 kW, with an annual power saved by 288 million kW·h, equivalent to 122 million RMB of electric rate economized.
  • Retrofit of Submerged Scraper Conveyors
    Li Jianrong, Ma Shisong, Song Yan
    2015, 29(5): 363.
    Abstract ( )   Knowledge map   Save
    An introduction is being presented to the operation principles and features of submerged scraper conveyors used for 1 000 MW power generation units, together with an analysis on the problems existing in the scraper conveyors, such as abnormal operation of the chain scission protection system, water waste caused by abnormal overflow, etc. Based on actual retrofit cases, comprehensive optimization measures were proposed by applying PLC control and optical ranging supplemented methods to enhance the reliability of the chain scission protection system and the overflow water control system. Results show that these measures have improved the security of relevant submerged scraper conveyors, achieving the goal to save energy.
  • Standard Selection for EMC Emission Test of ElectricalPenetration Assemblies in Nuclear Power Plants
    Zhao Xin
    2015, 29(5): 366.
    Abstract ( )   Knowledge map   Save
    An introduction is being presented to the electromagnetic compatibility (EMC) emission test requirements for qualification of the third generation nuclear power equipment. Based on comparative analysis of the methods, requirements and results respectively contained in MIL and IEC system, suggestions are proposed for standard selection on EMC emission test of relevant electrical penetration assemblies.
  • Contrastive Study on AP1000 Canned Motor RCP  and Wet Winding Motor RCP
    Shi Taofeng
    2015, 29(5): 370.
    Abstract ( )   Knowledge map   Save
    Based on contrastive study and analysis of the canned motor reactor coolant pump (RCP) and wet winding motor RCP from aspects of performance, structure, process complexity, lead time and cost, etc., the winding motor RCP is considered to be a potential selection for the third generation nuclear power plant, which may serve as a reference for the owners, design institutes, engineering companies in design, selection and procurement of nuclear reactor coolant pumps.
  • Application of Flowmaster2 Simulation in Springloaded ValveSelection for Highpressure Feedwater Heater System
    Yin Jiamin, Yang Jin
    2015, 29(5): 373.
    Abstract ( )   Knowledge map   Save
    An introduction is being presented to the functions of highpressure feedwater heater (AHP) system in CPR1000 nuclear power stations as well as to control principles of the bypass lines. Pipe models of AHP system are established by Flowmaster2 to simulate transient conditions during opening process of springloaded valve in the event of one bank of HP heaters are isolated. The set point pressure and normal operating pressure drop of springloaded bypass valve are given according to simulation results, which may serve as a reference for model selection of springloaded bypass valves.
  • Design of Early Warning System for Passive Safety Nuclear Power Plants
    Wang Lize, Cheng Junjie, Zhou Zhi
    2015, 29(5): 377.
    Abstract ( )   Knowledge map   Save
    For operation safety of nuclear power plants, an early warning mechanism was proposed for automatic operation of nuclear power plants, while the importance to set up the mechanism was analyzed. Based on simulation models of virtual nuclear power plants, an early warning system with realistic significance was designed for safety operation of actual nuclear power plants.
  • Research Progress of Simultaneous Dust Removal,Desulfurization and Denitrification by WESPs
    Guo Shiyi, Li Fuxiao, Ding Chenggang, Lu Jing,Pan Weiguo, Ding Honglei, Guo Ruitang, Luo Hancheng
    2015, 29(5): 381.
    Abstract ( )   Knowledge map   Save
    An introduction is being presented to the research progress of simultaneous dust removal, desulfurization and denitrification via wet electrostatic precipitators (WESPs), together with a description to the application status both at home and abroad. Results show that with advantages of small equipment investment, high removal efficiency and flexible layout, the WESP technology helps to realize dust removal, desulfurization and denitrification simultaneously.