Power Equipment

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  • 2017 Volume 31 Issue 2
    Published: 15 March 2017
      
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  • Numerical Simulation of Biomass Gasification at Low Equivalence Ratios
    Lu Jie, Jin Baosheng
    2017, 31(2): 71-75.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study the two-stage gasification technology, a three-dimensional numerical model was established to simulate the biomass gasification process in bubbling bed using k-ε turbulent model for the gas phase and kinetic theory of granular flow for the solid phase, and a chemical reaction sub-model was also used to study the change law of biomass gas composition with the equivalence ratio, oxygen concentration and flow velocity at low equivalence ratios, while the tar content in gas components was analyzed. Results show that with the rise of equivalence ratio, the concentration of CO and H2 first increases and then decreases, while that of CO2 decreases gradually. Whereas with the rise of oxygen concentration, the concentration of CO and CO2 increases rapidly, while the concentration of H2 decreases slightly. With the rise of flow velocity, the concentration of CO increases, while the concentration of CO2 decreases, with a slight increase of H2 concentration simultaneously. The tar content is relatively high in the outlet gases, so deep cracking is considered to be necessary in the next process.
  • Study on Method of Thermal Stability Test for Steam Turbine Rotors
    Gui Qizhi, Qin Qidong, Li Guangming, Liu Liangyu
    2017, 31(2): 76-80.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the principle of thermal stability test for steam turbine rotors, including an analysis on the physical meanings of data processing method prescribed in 4 evaluation criteria commonly used domestically and overseas, while their advantages and disadvantages as well as corresponding error sources were explored. Taking the thermal stability test for a 600 MW HP/IP steam turbine rotor as an example, the original data were processed respectively with the methods concerned in above four criteria, based on which, factors influencing the accuracy of each test method were analyzed.
  • 3D CFD Numerical Simulation of Cooling Water Flow in Steam Condensers Based on Porous Media Model
    Yi Siqiang, Yang Jianming
    2017, 31(2): 81-85.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To provide theoretical bases for design optimization of a condenser, the computational fluid dynamics method was used to carry out performance analysis of the condenser, while a porous media model was adopted to simplify its cooling water tube regions, and the model was further optimized by reducing the length of the tube region and correcting the resistance factor according to the reduced length, thus reducing the flow and diffusion of cooling water in the porous media model. The cooling water flow parameters were calculated through a 3-dimensional numerical simulation model, based on which the factors influencing the condenser’s performance were found to be as follows: the vortices existing in the inlet cooling water chamber, which increase the flow resistance; the cooling water flow differs a lot in different tube regions, which influences the performance of the condenser. Simulation results show that it is feasible to simplify the cooling water tube regions by porous media model.
  • Short-term Wind Speed Forecasting Using PCA-WNN Based on KMO-Bartlett Typical Wind Speed Selection
    Xie Kun, Zhang Junfang
    2017, 31(2): 86-91.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Against the redundancy of wind speed information in wind power prediction that results in difficulties for neural network to get the inherent law and therefore affect the training efficiency, the optimal wind speed data were selected for principal component analysis (PCA), while improved wavelet-BP neural network (WNN) was adopted for wind speed prediction. Based on KMO and Bartlett’s test of sphericity, the optimal wind speed data were selected and then extracted using PCA to optimize the inputs of neural network, thus improving the convergence rate and prediction accuracy of the network. By comparing the simulation results on wind speed data of a wind farm with other methods, the wavelet-BP neural network model based on PCA is proved to have high prediction accuracy and good generalization performance, verifying the correctness and effectiveness of this method.
  • Simulation Research on Trough Solar Organic Rankine Cycle Power Generation System
    An Yulei, Chen Jiufa, Zhang Zhibo
    2017, 31(2): 92-98.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    By combining the trough solar collector with an organic Rankine cycle (ORC) system, the influence of collector parameters on the power generation system was simulated. A mathematical model for the trough solar ORC system and calculation models for various parts of the system were established to simulate the whole circulation system using VB software. The effects of direct solar radiation intensity, the inlet temperature rise and the inlet flow rate of heat transfer fluid on both the overall efficiency of system and the output power of expander were analyzed. Simulation results show that when the inlet and outlet temperature of collector are fixed, the system would have an optimal flow rate relating to both the direct solar radiation intensity and the inlet temperature.
  • Experimental Research on Mercury Removal by Activated Carbon with CO2 in Simulated Flue Gas from Oxy-fuel Combustion
    Xue Yuan, Duan Yufeng, Wang Hui, Li Yaning, Lü Hao, Liu Meng
    2017, 31(2): 99-103.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To explore the influence of mercury removal by activated carbon under O2/CO2 flue gas atmosphere, a kind of commercial activated carbon was selected for adsorption experiments in a fixed bed reactor system and for temperature-programmed desorption experiments. Results show that compared with N2, pure CO2 atmosphere has little effect on Hg0 adsorption by activated carbon. However, the activated carbon performs better in simulated O2/CO2 flue gas atmosphere than in O2/N2 atmosphere under same conditions. SO2 inhibits and NO promotes the mercury removal by activated carbon, and their influence trends are consistent in both the simulated O2/CO2 and the simulated O2/N2 flue gas atmosphere.
  • High-voltage Insulation Systems for Wet Electrostatic Precipitator and the Techno-Economic Analysis
    Lu Qiliang, Chen Wei, Zhao Liang, Liu Pingyuan, Qi Qiming, Jiang Xi
    2017, 31(2): 104-106.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A study was conducted on the main factors influencing the performance of different high-voltage insulation systems for wet electrostatic precipitator, together with an introduction to the structure and features of 3 high-voltage insulation systems, and an analysis and comparison on their technical and economic characteristics. Results show that the operation reliability of the hot air blowing system is the highest, and its application range is the widest. For the anti-sweat porcelain bushing and drawn rod system, both the initial investment and the operation cost are the lowest, but its long-term operational reliability remains to be examined. Above study results may serve as a reference for selection of high-voltage insulation systems for wet electrostatic precipitators.
  • Waste Heat Recovery from Utility Boilers with Multi-stage Flue Gas Coolers
    Fu Yuling, Cai Wei, Jiang Haitao, Jia Minghua, Chu Xiaoliang, Wang Gang, Niu Tao, Yang Tianliang
    2017, 31(2): 107-109,116.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Multi-stage flue gas coolers were used to recover the waste heat from utility boilers. Based on a typical 300 MW unit, an analysis was conducted on deep utilization of waste heat in the flue gas, and the economic benefits of this unit during heating and non-heating period were proved to be remarkable, based on calculation using equivalent enthalpy drop method.
  • Investigation on Thermal Aging Test Parameters for Nuclear Safety Related Equipment Qualification
    Zheng Kaiyun, Yang Xiao, Chen Zhi
    2017, 31(2): 110-113.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the methodology of determination of thermal aging test parameters for nuclear safety related equipment qualification, including the Arrhenius model, ten-degree rule and the parameters recommended in relevant standards. Taking the qualification of class 1E electric actuator for CAP series nuclear power valves as an example, an illustration is performed to the procedure of determination of the thermal aging test parameters.
  • Treatment of Quality Problems Occurring in Manufacture of High/Low-pressure Heaters in a 1 000 MW Nuclear Power Unit
    Sun Xiaoshi
    2017, 31(2): 114-116.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems occurring in the manufacture of high/low-pressure heaters in conventional island of a 1 000 MW nuclear power unit, such as scored heat exchange tubes produced in repairing of seal welds, out-of-tolerance expanded tubes and corrosion failure after water pressure testing, for which preventive measures were put forward. This may serve as a reference for manufacture and supervision of domestic equipment in conventional island of 1 000 MW nuclear power units.
  • Cause Analysis of High Exhaust Gas Temperature in a 350 MW Supercritical Boiler and the Countermeasures
    Li Guangwei
    2017, 31(2): 117-120.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of high exhaust gas temperature during trial operation of a 350 MW supercritical boiler, an analysis was conducted on the causes from the perspectives of air preheater, boiler system, coal quality and operation mode, etc., combining with relevant test data and operation parameters, after which corresponding countermeasures were put forward to serve as a reference for treatment of similar problems.
  • Cause Analysis on Sudden Rise of Rotor Vibration in a 330 MW Turbo-Generator Set
    Jiang Lianyi
    2017, 31(2): 121-123.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To reduce the excessive vibration of a loaded generator rotor and to avoid the sudden rise of vibration during operation period, an analysis was conducted on the vibration characteristics, which was found to be caused by hindered expansion of rotor winding. The problem has been solved after relevant countermeasures were taken.
  • Maintenance of Heating Equipment for 1 000 MW Units During Shutdown and Standby Period
    Chen Yuzhong, Chen Shaohua, You Liang, Hu Lichuan, Jiang Yong
    2017, 31(2): 124-126.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a 1 036 MW ultra supercritical power unit as an object of study, the ammonia alkalinization drying method (hot furnace water) and ammonia water method were selected for the equipment maintenance during shutdown and standby period. Application scope and implementation process of the two methods were presented, while key points of the maintenance operation were analyzed. Results show that the two methods are simple, applicable, economical and feasible, which can greatly shorten the start-up time and guarantee the safe and stable operation of the unit.
  • Low-vacuum Analysis and Improvement for Steam Turbine Driving Induced Draft Fan in a 1 000 MW Coal-fired Unit
    Yang Biao, Yang Bo
    2017, 31(2): 127-131,136.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To reduce power consumption rate, the induced draft fan in some coal-fired power plants is driven by steam turbine, which makes the cold end optimization become more complex. To solve the low-vacuum problem occurring in the steam turbine driving induced draft fan of a 1 000 MW coal-fired unit, an applicable operation scheme was proposed, considering cold end optimization of the unit and actual operability of the scheme.
  • Study on Sealing Tile Oil Return Problem in the Generator of Single-flow 4-tile Structure
    Zhao Guoqin
    2017, 31(2): 132-136.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of oil leakage into the stator of a generator with single-flow 4-tile structure during start-up and shut-down period, an analysis was conducted to the sealing principle and oil returning status of the sealing tile. Results show that the oil leakage is found to be caused by the air blockage in the oil return line on hydrogen side, which can be solved by eliminating the air blockage.
  • Optimization on Start-up Process of a Gas Turbine Lifting Oil System
    Liu Qianju, Tang Jian, Zhang Shuai
    2017, 31(2): 137-139,144.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of low oil pressure existing in the lifting oil system of a F class gas turbine combined cycle power unit during erection, commissioning, or after long-term shutdown of the gas turbine, leading to improper interlock start-up of the standby pump, which could not be put into operation again in the case of normal operation, or once a failure is encountered by the main pump, an analysis and on-site inspection & testing were carried out to the lifting oil system, so as to improve its technological process and optimize the structure, and finally to enhance the safety of the power unit.
  • Analysis and Optimization of the Control System in a 300 MW Direct Air-cooling Unit
    Lan Ligang, Wu Guangsheng, Ma Rui, Chen Guanhua
    2017, 31(2): 140-144.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is presented to the ACC full automatic control strategy of Stanari 300 MW unit in Bosnia-Herzegovina, together with an analysis on its sub-control systems, such as the ACC sequence control, the turbine exhausting pressure regulation, the freezing protection of parallel cells and the anti-frosting logic of reflux cells, etc. For problems occurring during commissioning and operation of the unit, improvement measures were put forward and taken. Results show that the scheme can help to secure the safety during start up, shutdown and economic operation of the unit, which is applicable to all kinds of accidental conditions, and therefore may serve as a reference for full automatic control of direct air-cooling systems.