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  • Research & Analysis
    Optimization on SOFA Duct Arrangement for Boilers AdoptingTwo-stage Low NOx Combustion Technology
    Xu Weijun
    2014, 28(4): 227-230.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of insufficient separated overfire air (SOFA) volume at low load of boiler caused by unreasonable arrangement of SOFA duct found during low NOx combustion retrofit, a theoretical analysis was carried out on both the flow resistance and pressure distribution of secondary air in the wind box, after which the problem was found to be caused by large SOFA duct resistance and small pressure difference between the wind box and furnace on the upper part. Based on above analysis, an optimization was conducted to the SOFA duct arrangement that adopts advanced composite air staging combustion technology in Shanghai Boiler Works Co., Ltd. Application results show that the problem of insufficient SOFA volume at low load of boiler is finally solved, and the purpose of low NOx emission can be achieved at any loads.
  • Research & Analysis
    6Analytic Study on Airfoil Design of Supersonic Turbine Cascade
    Li Haitao, Yang Jiandao, Zhou Daiwei
    2014, 28(4): 231-236.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on Non-uniform rational B-spline (NURBS) theory and characteristic line modeling technology, the airfoil geometry generation of supersonic turbine cascade was researched, while the blade design software was developed by using C++ language and MFC technique. A supersonic turbine cascade profile was designed with the software developed, and its design and off-design performance were analyzed combined with the computational fluid dynamics (CFD) method. Results show that the software previously developed is proved to be effective in the airfoil design of supersonic turbine cascade, which may therefore serve as a reference for airfoil design and development of low-pressure last-stage turbine blade in actual engineering applications.
  • Research & Analysis
    Analysis on System Configuration of Coal Water Slurry Boilersunder Different Combustion Modes
    Lu Wanglin
    2014, 28(4): 237-241.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Coal water slurry (CWS) boilers can be divided into atomization combustion boiler and circulating fluidized bed boiler according to different combustion modes. Four systems of a 65 t/h boiler constructed in Guangdong are analyzed, such as the CWS supply system, air and flue gas system, desulfurization & dust removal system and the denitration system, etc., after which typical equipment configurations are put forward for all the systems under above two modes. By comparing the material consumption, the building expenditure and the operation cost in boiler house construction period, applicable ranges of the two combustion modes are obtained respectively.
  • Research & Analysis
    sis on Energy Consumption of a 600 MW Supercritical Turbine Unit
    Ruan Shengqi, Cheng Rongzhong, Ren Lei, Wu Hongtao, Hu Zhongqiang
    2014, 28(4): 242-244.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of high energy consumption in a 600 MW supercritical turbine unit, due to low flow efficiency of the steam turbine, high consumption rate of the reheater attemperating water, and large terminal temperature difference of the condenser at low load, etc., thermal performance tests were performed to the unit before overhaul, so as to analyze the problems existing in flow passage and auxiliary equipment of the steam turbine, as well as the resulted influences upon the turbine performance, thus providing reference for design of power plant energy conservation.
  • Research & Analysis
    Site-stream Treatment for Circulating Cooling Waterof Cement Plant Waste Heat Power Station by Reverse Osmosis Method
    Zhang Juan
    2014, 28(4): 245-247.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking the site-stream treatment process for circulating cooling water of a cement plant waste heat power station as an example, an introduction is being presented to the reverse osmosis desalination process and equipment, including the pretreatment, reverse osmosis and water reuse facility, of which the features are described and the benefits are evaluated. Results show that 75% pure water produced by the reverse osmosis facility is reused as make-up and circulating cooling water of the boiler, and the high salt drainage can be used in industrial production of the cement plant, thus achieving zero discharge of the wastewater.
  • Research & Analysis
    Diagnosis and Analysis on High Backpressure of a 330 MW Unit
    Xu Xing, Huang Qilong, Dai Weibao
    2014, 28(4): 248-250.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To find the causes leading to high backpressure of a 330 MW subcritical unit for over a year since its operation, an analysis is performed with focus on the condenser, the circulating water system and the heat transfer in the aspect of equipment selection, performance parameters and test calculation, etc. The fouling conditions diagnosed with the cleanliness factor obtained through testing agree well with the results of on-site inspection, proving that it is feasible to use cleanliness factor to diagnose the fouling condition of the condenser.
  • Research & Analysis
    Design and Test on Runback Function of a 1 000 MW Unit
    Gao Sheng, Yao Yingying, Zhang Xuyan, Zhao Zhong
    2014, 28(4): 251-254.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To realize the runback (RB) function of a 1 000 MW unit, a coordinate control system is designed, based on which, special RB tests are performed under different working conditions. Effectiveness and rationality of the design are proved by the RB tests.
  • Research & Analysis
    Application of Automatic Feed Pump Paralleling in Ultra-supercritical Units
    Chen Qin, Mao Jinwei, Chen Chaorong
    2014, 28(4): 255-257.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the fact that the feed pump paralleling in large power units is very complex, and the manual paralleling has certain risks, the process of automatic pump paralleling for an ultra-supercritical unit is described, while corresponding control strategies put forward as well. Operation practice shows that main parameters of the unit can keep stable after automatic feed pump paralleling, which subsequently results in relieved operating strength of relevant personnel as well as improved automation level and reliability of the unit.
    • Material & Technology
  • Material & Technology
    Material Selection for High-temperature Reheater Headerand Piping of a 600 ℃/620 ℃ Ultra-supercritical Unit
    Mao Shiyong, Yang Huachun, Yang Jinbing, Lai Xianhong, Yang Xiaochuan
    2014, 28(4): 258-261.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on operation conditions, material selection principles, regulations and steel series for boiler piping, and the pipe manufacturing capability, candidate materials for high-temperature reheater header and piping of a 600 ℃/620 ℃ ultra-supercritical boiler are analyzed and discussed, after which it is suggested to adopt P92 steel pipe. The feasibility to control and stabilize the property of P92 steel pipe is discussed in consideration of the quality and property issues concerned by the power industry.
  • Material & Technology
    On-site Treatment of Steam Leakage at Turbine Casing Split
    Shao Jianming, Zhou Yong, Du Bingqian
    2014, 28(4): 262-265.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Considering the high-temperature expansion property of Ni-based metallic seal and its sealing principle, causes that may lead to steam leakage at casing split of large capacity steam turbines were analyzed, based on which an on-site treatment measure was proposed by simultaneously adopting both the Ni-based metallic seal and the seal groove at the leaking position. Specific groove cutting machine was designed and a complete set of groove cutting procedure was worked out through trial practice. Results show that the steam leakage can be prevented by reasonably setting the seal preload so as to guarantee enough expansion of the sealing strip and to make it contact with the sealing surface tightly.
  • Material & Technology
    Cracking Failure Analysis for a High-temperature Superheater
    Zhou Liqin, Chen Xun
    2014, 28(4): 266-268.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To find the causes leading to longitudinal and circumferential cracks on elbow of a high-temperature superheater, a series of tests were conducted, such as visual examination, chemical composition analysis, mechanical property analysis, metallographic examination and microstructure analysis, etc. Results show that the longitudinal cracks spreading from inner to outer wall surface at the bending area are caused by stress corrosion, while the circumferential cracks spreading from outer to inner wall surface are caused by corrosion fatigue.
    • Operation & Retrofit
  • Operation & Retrofit
    Retrofit Optimization on a Tiny-oil Ignition System for 1 175 t/h Boiler
    Hao Jian, Wang Guangyan, Zhang Jinbao
    2014, 28(4): 269-271.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Retrofit optimization was carried out to a tiny-oil ignition system based on analysis of the problems occurring during the boiler operation, such as mill trip during ignition, existence of ember after shut off of small oil gun, oil gun blocking, and no flam detected, etc., to which corresponding optimization measures were put forward and implemented, which have helped to raise both the safety and reliability of the boiler tiny-oil system during ignition.
  • Operation & Retrofit
    Economizer Retrofit for a B&WB-410/9.8-M Coal-fired Boiler
    You Hongyan, Jiang Xiaofeng, Zhu Yifei
    2014, 28(4): 272-274.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems of frequent tube burst occurring in the economizer of a coal-fired boiler, due to severe erosion of economizer tubes caused by increased flow rate in no ash deposition areas resulted from serious ash deposition on the spirally finned tube surface, a retrofit scheme is proposed by adopting H-type fin tube and adding antiwear cover. According to thermodynamic calculations, the flue gas velocity of low-temperature economizer can be increased from 8 m/s to 10.5 m/s, thus ash deposition can be avoided under low load condition, and therefore antiwear property can be improved for the economizer tubes.
  • Operation & Retrofit
    Hidden Danger Analysis and Upgrading of a 9FA Gas Turbine Compressor
    Zhuang Qingquan, Jing Di
    2014, 28(4): 275-278.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An introduction is being presented to the operation and maintenance of a 9FA+e gas turbine compressor in Caojing Thermal Power Co., Ltd., together with an analysis performed to the hidden danger that may bring troubles to the unit operation, from the aspect of operation mode, component design, etc., after which a retrofit scheme according to upgrade package 4th is proposed and implemented. Results show that both the performance and reliability of the compressor have been improved after the retrofit.
  • Operation & Retrofit
    Causes and Countermeasures for High Exhaust Temperatureof Heat Recovery Boilers
    Chen Jing, Pang Jianfeng, Deng Mian
    2014, 28(4): 279-282.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem of high exhaust temperature of a heat recovery boiler, a simulation model basically consistent with actual operation parameters was established based on its original design parameters. By comparison among three different retrofit schemes, two of them were recommended to be used for the boiler retrofit according to actual situation of the power plant. Operation practice shows that the exhaust temperature of the heat recovery boiler has been reduced, achieving the purpose of energy saving and emission reduction.
  • Operation & Retrofit
    Retrofit on Front Air Ejector of Water Ring Vacuum Pumps
    Cai Ling
    2014, 28(4): 283-284.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problem occurring in the vacuum pump of a power plant, such as excessive noise and vibration, insufficient vacuum degree and serious cavitation, etc., it is suggested to add a front air ejector to the vacuum pump. Results show that after installation of air ejector, the noise and vibration are reduced, the ultimate suction pressure is promoted, the cavitation phenomenon is avoided, meaning that safety and stable operation of the pump is guaranteed.
  • Operation & Retrofit
    Counterweight Handling for Fallen Blade Failure of a 25 MW Steam Turbine Rotor
    Ji Liepeng, Zhou Weimin
    2014, 28(4): 285-287.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To overcome the fallen blade failure occurring to a 25 MW steam turbine unit during operation, it is suggested to perform counterweight handling to the steam turbine rotor. Through careful calculation, weighing and installation, the steam turbine was repaired and back to work in a short time. Specific procedures of the overhaul by adding counterweight to the steam turbine are described. Operation practice shows that the method of adding counterweight temporarily is quite a better choice.
  • Operation & Retrofit
    Causes Analysis and Countermeasures for Thrust Pad Wearingof a Feed Pump Turbine
    Guan Panlong, Wang Fei, Chen Nianzhong
    2014, 28(4): 288-293.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To overcome the thrust pad failure of a feed pump turbine during tripping out of a 330 MW heat supply unit, an analysis was performed from the aspects of thrust bearing malfunction, turbine blade fouling, feed water pump abnormal operation, steam flow increase, turbine water impact and thermal protection problems, etc. Results show that the wearing is caused by rapid inlet flow increase in operation of the feed pump turbine, the excessive axial thrust due to local water impact of the rotor, and the thermal protection logic imperfections. Besides, corresponding preventive and treatment measures are proposed for design and operation of the system.
  • Operation & Retrofit
    Reasons on Condenser Vacuum Decline during Startupof a Combined Cycle Unit
    Men Jincheng
    2014, 28(4): 294-295.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems of condenser vacuum decline during cold start of a M701F4 gas-steam combined cycle unit, due to accumulation of large volume of non-condensable gases in the waste heat boiler, which enters the condenser, it is suggested to vent the non-condensable gases adequately from the high/medium/low-pressure main steam piping and the reheater system before startup process, and to manually control the opening time of vent valves located at the outlet of high/medium/low-pressure superheater and reheater during startup process, so as to prevent excessive decline of condenser vacuum during startup of the unit.
  • Operation & Retrofit
    Optimization of a Turbine Overspeed Protection System
    Li Ke
    2014, 28(4): 296-299.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The function of a turbine overspeed protection system based on Symphony software is described in detail, to which necessary improvement and optimization are implemented on the software and hardware that have problems in actual application. Operation practice shows that the protection actions are completely consistent with actual working conditions after improvement on the software and hardware of the turbine overspeed system.
  • Operation & Retrofit
    Optimization on Feed Water Control during Startup of a 660 MWUltra-supercritical Boiler with Re-circulating Pump
    Xi Chengchao
    2014, 28(4): 300-304.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An analysis is conducted on problems existing in the automatic feed water control during startup of a 660 MW ultra-supercritical boiler with re-circulating pump, after which it is suggested to calculate the main steam flow that will later on be taken as the parameters for feed-forward control of the feed pump, with such parameters as the main steam pressure, high pressure bypass valve opening, turbine rotational speed, and generator load, etc. According to the main steam flow calculated and the actual rotational speed of pump, both the feed water bypass valve opening and the PID parameters of feed water control can be adjusted and a parameter adaptive logic can be added. Actual operation shows that the modified feed water control logic meets the whole-process automatic control requirements during startup and normal operation of the unit.
    • Environmental Technology &Equipment
  • Environmental Technology &Equipment
    Application and Improvement of Absorption Method in Carbon Captureand Storage of Thermal Power Plants
    Li Rui, Wang Shuguang, Tang Zhaofang
    2014, 28(4): 305-309.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The roles of carbon capture and storage technology in controlling CO2 emission from thermal power plant are described in detail, with focus on the carbon capture process by absorption method. Meanwhile overseas application cases are listed and corresponding characteristic analysis is performed. It is pointed out that the absorption method shall be further optimized from two aspects, i.e. the improvement on chemical reaction process, and the integration of decarbonization system with thermal system of the power plant.
  • Environmental Technology &Equipment
    Gas-Gas Heater Sealing Technology Improvement and Applicationfor Desulfurization System of a Coal-fired Power Plant
    Li Hong, Zhang Quansheng
    2014, 28(4): 310-314.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the air leakage problem in desulfurization system gas-gas heater (GGH) of a 600 MW coal-fired boiler, studies were carried out for improvement of the GGH sealing technology in the aspect of equipment design, construction, operation and maintenance, etc., after which countermeasures were proposed and implemented by adopting adjustable elastic bi-layer seals.