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    Research & Analysis
  • Research & Analysis
    Analysis on Internal and External Flow Fieldof SCAL Indirect Air Cooling Towers
    Chai Yanqin, Tian Songfeng, Zhou Guangsha
    2014, 28(1): 1-4.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A detailed geometric model was established for heat transfer element of a SCAL indirect air cooling system according to the actual size of radiating tube bundle in tower bottom and the arrangement mode of cooling triangle, based on which three-dimensional numerical simulation was conducted to the internal and external flow field of the air cooling tower by Fluent software, while the influence of ambient wind velocity on its operating characteristics studied. Results indicate that when the ambient wind velocity is higher than 4 m/s, high-speed air flow collects at both sides of the tower, in which case the intake velocity is the lowest due to the tangential force of transverse wind; both the ventilation rate and outlet velocity of the air cooling tower increase first and decrease later on with the rise of ambient wind velocity.
  • Research & Analysis
    Finite Element Calculation on Strength ofLow Pressure Rotor for Nuclear Steam Turbines
    Zhu Wei, Deng Zhicheng, Shen Xiulan, Wang Yong
    2014, 28(1): 5-7.
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    The temperature field and stress field of a low pressure rotor for nuclear steam turbine were calculated under steady-state rated load, cold start and normal shutdown conditions using finite element method. Calculation and analysis results indicate that the low pressure rotor has qualified strength design, rational structure design and reasonable start up and shutdown curves under steady-state rated load, cold start and normal shutdown conditions.
  • Research & Analysis
    Design Features of Large Air-cooling Steam Turbines
    Xu Jinfeng
    2014, 28(1): 8-10.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The operation condition of air cooling steam turbine has the features of high average value, great and frequent change of back pressure, which therefore brings difficulties to structural design of the turbine, especially in the design of low-pressure module with obvious difference from that of water-cooling unit. Taking the design of a 600 MW direct air-cooling double flow turbine as an example, an introduction is presented to the choices of its structure, power and auxiliary system, etc., which may serve as a reference for design of large air-cooling steam turbines.
  • Research & Analysis
    Application of PSO-based Variable Universe Fuzzy PID Controllerin Superheated Steam Temperature Control System
    Shang Qiang,Wang Mingchun,Yin Lingxiao
    2014, 28(1): 11-14.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A fuzzy PID controller was designed aiming at the problem that it is difficult to establish a precise mathematical model for superheat steam temperature of boilers due to its features of large lag, great inertia, etc. Through online adjustment of PID parameters by fuzzy reasoning, combining with the ideas of variable universe to improve the control system, and introducing the particle swarm optimization (PSO) algorithm to the variable universe fuzzy controller, the quantization factor and three parameters Kp, Ki and Kd of the PID were optimized. Simulations were conducted to the superheat steam temperature control system using the fuzzy PID controller. Results show that the PSO-based variable universe fuzzy PID control has strong robustness and anti-interference capability, which therefore is apparently superior to traditional PID control.
  • Research & Analysis
    Experimental Study on Pulverizing Characteristics of a BBD4360 Doubleinlet Doubleoutlet Coal Mill
    Ma Yuankun
    2014, 28(1): 15-18.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Experimental tests were performed to a BBD4360 doubleinlet doubleoutlet coal mill, so as to study its pulverizing characteristics. Results show that the fineness of pulverized coal increases with rising velocity of dynamic separator, reducing opening of capacity air damper, and with lowering outlet temperature of coal mill. In addition, inverse correlation exists between the unit consumption of coal pulverizing and the mill output.
  • Research & Analysis
    FCB Test and Control Strategy Optimization of a 660 MW Unit
    Wang Li, Lu Xuenong
    2014, 28(1): 19-22.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the fast cut back test results of a newly-built 660 MW unit, the equipment configuration and critical control points that are necessary for realizing the functions were analyzed, so as to help its safety shutdown, reduce both the frequency of boiler MFT and the occurrence of oxide scales in heating surfaces of the boiler, and make the unit be capable of recovering load quickly, which is of great importance to the improvement of power grid safety.
  • Research & Analysis
    ptimization on Combustion Control Strategy fora 260 t/h Coking Coal Co-firing CFB Boiler
    He Yueke, Tian Xiaolan, Zou Baochan, He Erdong
    2014, 28(1): 23-26.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A boiler system and its process flow were introduced in combination with the practical experience of burning petroleum coke in a 260 t/h CFB boiler. Aiming at the control objectives and difficulty of the boiler control system, a boiler master feedforward modification scheme was put forward, such as adding main steam pressure set value differential, drum pressure differential, and energy demand baseline function, etc. Moreover, control schemes for primary air, secondary air and bed temperature control systems were improved and optimized. Results show that the maximum dynamic deviation of steam pressure is only 0.55 MPa and the change of bed temperature is less than 25 K, under the load disturbance of 5 MW, which meets the requirements of relevant standards.
  • Research & Analysis
    Study and Application of Condenser Cleanness Monitoring Methods
    Yang Jiaji, Huang Ruguang
    2014, 28(1): 27-29.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As condenser cleanness has great influences on economical efficiency of steam turbines, a method was put forward for monitoring the condenser cleanness. Two parameters “condenser cleanness percentage” and “condenser tube wall fouling resistance” were calculated by establishing a condenser cleanness monitoring model, so as to evaluate the cleanness of condenser. In practical operation, Excel model was used to calculate and track the real time condenser cleanness, so as to optimize the timing of washing by rubber balls and reach the purpose of energy saving and consumption reduction. Good effects were obtained via above method.
  • Research & Analysis
    Experimental Study on Partial Discharge Test of Mediumvoltage Electrical Penetration Assemblies for Nuclear Power Station
    Hu Ziying, Yu Gaowei, Wu Keke, Zhu Xiaoping
    2014, 28(1): 30-33.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction was presented to functions and electric parameters of the mediumvoltage electrical penetration assembly for AP1000 thirdgeneration nuclear power stations, as well as to the requirements of IEEE 317—1983 and GB 13538—1992 on the partial discharge test. A set of partial discharge test circuit was designed by the pulse current method of partial discharge measurement approach according to above test requirements and electric parameters, and a structural improvement scheme was put forward by contrast test that can reduce the magnitude of partial discharge of the mediumvoltage electrical penetration assembly, while corresponding interference identification in test process and relevant antiinterference measures analyzed in details.
  • Research & Analysis
    IP Cylinder Start-up Mode and Correct Cylinder SwitchingOperation for Large-capacity Steam Turbines
    Cao Chao, Zhang Peng, Zhou Hongmei
    2014, 28(1): 34-36.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The advantages of intermediate pressure (IP) cylinder start-up mode of steam turbines were introduced and corresponding correct cylinder switching methods were analyzed and summarized, so as to guarantee the safety and stability of relevant cylinder switching processes and therefore secure the safety of the whole unit.
    • Operation & Retrofit
  • Operation & Retrofit
    Wall Thickness Management Improvement for Steam-WaterPipes in Secondary Loop of Nuclear Power Plants
    Luan Xingfeng, Zheng Hui, Wang Donghui, Zhang Wei, Bian Chunhua
    2014, 28(1): 37-39.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the concept of wall thickness reduction in the secondary loop steam-water pipes of nuclear power plant, together with an analysis on the mechanism and generation conditions of the wall thickness reduction. A long-term, integral and effective management system has been established based on the Surveillance Guideline for Conventional Island Steam-Water Pipes, of which the effectiveness has been proved by comparison between actual measurements and simulation results. Moreover, the significance of sticking to the management system is emphasized.
  • Operation & Retrofit
    Economic Analysis on Retrofit for Energy Conservationof Condenser Air Exhaust System in a 300 MW Thermal Power Unit
    Xue Dongfa, Wang Bo, Ma Tingshan, Zheng Likun
    2014, 28(1): 40-42.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A comparison was made to the performance of two condenser air extraction modes—water jet air ejector and water ring vacuum pump. To replace the water jet air ejector with water ring vacuum pump, a retrofit scheme was introduced, of which the coal and power saving benefits were analyzed in combination with a retrofit practice for condenser air exhaust system in a 300 MW thermal power unit. Results show the retrofit has achieved good effects.
  • Operation & Retrofit
    Reliability Analysis and Optimization of Continuous Flue Gas Monitoring System
    Chen Qin, Shu Maolong, Sun Renlong
    2014, 28(1): 43-45.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the continuous flue gas monitoring system in a 1 000 MW power unit, together with an analysis on the common faults, and a discussion on its operation reliability. Moreover, improvement measures are put forward for the power source, oxygen analyzer and sampling pipeline, while suggestions proposed for optimization of equipment operation environment and for strengthening of equipment maintenance management.
  • Operation & Retrofit
    Retrofit on Power Source of Electrostatic Precipitatorin Thermal Power Plants
    Chen Jianwei
    2014, 28(1): 46-48.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the dust removal efficiency and reduce energy consumption of electrostatic precipitator, a retrofit scheme was put forward for the power source by changing its mode from main-frequency power supply to high-frequency power supply. After retrofit, the outlet dust concentration of electrostatic precipitator drops from 30.2 mg/m3 to 5.8 mg/m3, with a reduction rate of dust concentration increased from the original 76.7% to 80.8%; the energy saving rate gets up to 69.6%; the dust removal efficiency rises from the original 99.6% to 99.68%. The objectives of efficiency improvement and energy saving are both reached simultaneously.
  • Operation & Retrofit
    Improvement on LVRT Capability of Coal Feeder and its Application
    Yu Weiquan, Ma Zhixing, Fu Fuqiang, Zhou Jiajie, Wang Ling, Wang Shuguang
    2014, 28(1): 49-51.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Hidden troubles caused by low-voltage faults to coal feeder in thermal power plant were analyzed, the method of improving the low-voltage ride through (LVRT) capability of coal feeder was introduced, and a retrofit example was presented, in which the purpose of improving the LVRT capability was achieved under the premise that no LVRT device was added.
  • Operation & Retrofit
    Anti-wear Analysis on the Chain of Scraper Slag Conveyors
    Bai Xinglong, Shi Changfu, Yu Fei
    2014, 28(1): 52-56.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To reduce the failure caused by chain wear in scraper slag conveyor for purposes of improvement on unit safety and stable operation, anti-wear measures were put forward to elongate the service life of relevant chains. Practices indicate that the chain wear can be effectively alleviated by reasonable design of chain washing water, necessary improvement on guide roller seal and careful adjustment of the slag conveyors running speed.
  • Operation & Retrofit
    Retrofit for Old Electronic Weighing Type Coal Feeders
    Li Lei, Ji Wenming, Cui Lüxing
    2014, 28(1): 57-60.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To overcome the deficiency of control system for old electronic weighing type coal feeders, such as low reliability and high failure rate, etc., a retrofit scheme was put forward using CS2024 control system. The precision and efficiency of coal feeder were improved by adopting new microcomputer control system, introducing special variable frequency motor and high-precision weighing sensor, and by using electronic over-current relay to replace the traditional mechanical cleaning shear pin. Practices indicate that the CS2024 control system is technologically mature, with which the retrofit objectives can be achieved completely.
    • Environmental Technology &Equipment
  • Environmental Technology &Equipment
    Application of Wet Electrostatic Precipitator in Coal-fired Power Plants
    Jiang Haitao, Tian Shaogang, Fu Yuling, Jia Minghua, Zhang Yubin
    2014, 28(1): 61-64.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the principle, structure and application of wet electrostatic precipitator in power plants at home and abroad, together with an analysis performed on problems to be solved to develop the wet electrostatic precipitator suitable for domestic coal-fired power plants.
  • Environmental Technology &Equipment
    Application Optimization of SCR Denitrification Technologyin a 3 033 t/h Boiler
    Yang Bo, Lin Jianhui, Zeng Biqun
    2014, 28(1): 65-69.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the application status of selective catalytic reduction (SCR) flue gas denitrification system in a 3 033 t/h boiler, together with an analysis on problems existing in the SCR denitrification process. To reduce the NOx emission, ammonia escape rate and ammonia injection rate, a series of retrofit measures were proposed and taken, after which good effects are obtained, such as reduced NOx emission, stabilized operation of the SCR denitrification system, etc.
    • New Energy Technology
  • New Energy Technology
    ExtJs-based Photovoltaic Power Prediction System
    Li Youwen, Wang Zhixin, Chu Hongjian, Qin Zheng, Bao Demei
    2014, 28(1): 70-74.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In light of the significance of photovoltaic power prediction for keeping power balance and continuous and effective operation of the power grid during photoelectric grid connection, an implementation model of ExtJs-based photovoltaic power prediction system was introduced. An introduction was presented to the front-end technology ExtJs used in the development process and the interactive mode between its MVC framework and backend server. A description was made to the algorithm of adaptive logic network for prediction of function modules in the system. An evaluation was carried out to the performance of the prediction system. Actual operation results indicate that the system has features of good operability, easy maintenance and high prediction accuracy.