超临界电站锅炉高温过热器管壁磨损数值研究
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摘要
高温烟气磨损是影响高温过热器安全长周期运行的主要因素,但锅炉系统高温过热器内部管排数目众多,烟气流动复杂多变,难以得到精确的磨损速率。利用Fluent软件对某电站锅炉系统的高温过热器进行数值模拟,研究了过热器内部流场分布规律。结果表明:最大磨损速率为1. 55×10~(-7)kg/(m~2·s),结合材料密度计算可得磨损减薄速率为0. 609mm/a;磨损速率最大的区域为靠近烟气入口侧的最外层管道下方及底部;烟气速度是影响管排磨损速率的因素之一。
This paper would like to make a simulated study on the process with the FLUENT software to expose the flow field distribution in the superheater of the supercritical power station boiler system. As is known,the erosion caused by the high temperature flue gas remains the main factor that may influence the long-term safety operation of the high temperature superheater,due to the fact that lots of pipes in the boiler system are working there,with the risk of the gas flowing inside unpredictable.Therefore,it is difficult to forecast the precise working life of the system,which may account for the need to establish a numerical calculation model based on the actual size of such high temperature superheater on-spot boiler system. The said model we have proposed is actually composed of a complicated hexahedral and tetrahedral grid,with its boundary conditions being framed to the velocity inlet and the pressure outlet and with the velocity of the flue gas at the inlet being 20 m/s. What is more,the pressure of the flue gas at the outlet serves as 1. 1 kP a whereas the pressure and velocity distribution of the gas phase has been worked out through a standard κ-ε model. Besides,the discrete phase model adopted can be used to simulate the wearing rate distribution and the movement of the particles in different sizes. Under such a situation,the mass flow rate of the injected particles should be of 0. 072 kg/s,with the particle size ranging from 1 μm to 27μm,and their materials can be made of coal ash particles. The analysis results reveal that their velocity distribution should be at different heights of the pipe row. The area with the highest wear rate lies in the lower part with the bottom of the outermost pipe lying near the inlet side of the flue gas,while the maximum wear rate stands about 1. 55 × 10~(-7) kg/( m~2·s). In combination with the material density,the wear reduction rate turns to be 0. 609 mm/a.And,since the flue gas velocity is a main factor that may affect the pipe wear rate,the particles in bigger sizes can be more likely to suffer more wear on the pipe rows. Hence,it can be seen that the research results of this paper can provide a basis for ensuring the long-term safe and stable operation of the boiler.
This paper would like to make a simulated study on the process with the FLUENT software to expose the flow field distribution in the superheater of the supercritical power station boiler system. As is known,the erosion caused by the high temperature flue gas remains the main factor that may influence the long-term safety operation of the high temperature superheater,due to the fact that lots of pipes in the boiler system are working there,with the risk of the gas flowing inside unpredictable.Therefore,it is difficult to forecast the precise working life of the system,which may account for the need to establish a numerical calculation model based on the actual size of such high temperature superheater on-spot boiler system. The said model we have proposed is actually composed of a complicated hexahedral and tetrahedral grid,with its boundary conditions being framed to the velocity inlet and the pressure outlet and with the velocity of the flue gas at the inlet being 20 m/s. What is more,the pressure of the flue gas at the outlet serves as 1. 1 kP a whereas the pressure and velocity distribution of the gas phase has been worked out through a standard κ-ε model. Besides,the discrete phase model adopted can be used to simulate the wearing rate distribution and the movement of the particles in different sizes. Under such a situation,the mass flow rate of the injected particles should be of 0. 072 kg/s,with the particle size ranging from 1 μm to 27μm,and their materials can be made of coal ash particles. The analysis results reveal that their velocity distribution should be at different heights of the pipe row. The area with the highest wear rate lies in the lower part with the bottom of the outermost pipe lying near the inlet side of the flue gas,while the maximum wear rate stands about 1. 55 × 10~(-7) kg/( m~2·s). In combination with the material density,the wear reduction rate turns to be 0. 609 mm/a.And,since the flue gas velocity is a main factor that may affect the pipe wear rate,the particles in bigger sizes can be more likely to suffer more wear on the pipe rows. Hence,it can be seen that the research results of this paper can provide a basis for ensuring the long-term safe and stable operation of the boiler.
引文
[1] ZHU Baotian(朱宝田),ZHAO Yi(赵毅). Development of ultra-supercritical power generation technology in China[J]. Huadian Technology(华电技术),2008,30(2):1-5.
[2] LE Changyi(乐长义). Current status and prospects of foreign supercritical parameter power station boilers[J].East China Electric Power(华东电力),1985(11):65-71.
[3] ZHANG Lixin(张立新). Improving the influence of steam parameters on the economics of thermal power units[J]. Architectural Engineering Technology and Design(建筑工程技术与设计),2016(19):2427.
[4] YAO Yanqiang(姚燕强). Research of SC/USC coalfired power generation technology[J]. Huadian Technology(华电技术),2008,30(4):23-26.
[5] WANG Dajiang(王大江),ZHU Jian(朱健). Failure analysis of blast furnace high temperature superheater tube blasting[J]. Hot Working Technology(热加工工艺),2014,43(18):223-224,229.
[6] QING Li(卿黎),ZHANG Shengyue(张胜跃),ZHANG Yudong(张宇栋),et al. Failure mode analysis for the pressure-bearing components of the power-generating boiler[J]. Journal of Safety and Environment(安全与环境学报),2016,16(4):17-22.
[7] DONG Yuliang(董玉亮),LI Yaqiong(李亚琼),WANG Zhenhe(王珍和),et al. Safety evaluation on fuel-fired power plant based on evidence theory[J]. Journal of Safety and Environment(安全与环境学报),2010,10(3):179-183.
[8] YANG Zhen(杨震). Mechanism for utility boiler tube failure and measures to improve reliability[J]. Boiler Technology(锅炉技术),2001,32(12):1-7.
[9] LI Zhenggang(李正刚),WANG Zhiwu(王志武),ZHAO Bo(赵博),et al. Statistical analysis for four tubes leakage failure of power plant boiler[J]. Heat Treatment of Metals(金属热处理),2007,32(S1):36-39.
[10] LI Zhongshan(李忠善),ZHU Changyu(朱昌煜),LI Zhigang(李志刚). Application of multistage anti-wear device in 480 t/h circulating fluidized bed boiler[J].Inner Mongolia Electric Power(内蒙古电力技术),2010,28(3):50-51.
[11] CHEN Baokang(陈宝康). Theoretical and experimental research on monitoring and optimizing soot blowing of heating surface boiler in power station boiler(电站锅炉受热面污染监测及优化吹灰的理论与实验研究)[D].Baoding:North China Electric Power University,2004.
[12] MA Jianguo(马建国). Analysis on the influence of boiler operation and management on the wear of low temperature heating surface[J]. Ningxia Electric Power(宁夏电力),2009(S1):225-227,236.
[13] YING Mingliang(应明良),YU Ji’an(俞基安),JIN Di(金涤),et al. Erosion calculation and residual life forecast of enclosure wall tube's elbow[J]. Zhejiang Electric Power(浙江电力),2006(4):14-17.
[14] RAY A K,TIWARI Y N,CHAUDHURI S,et al. Remaining life assessment of service exposed reheater and superheater tubes in a boiler of a thermal power plant:high temperature materials and processes[J]. High Temperature Materials&Processes, 2002, 21(1/2):109-122.
[15] JING Xin(景新). Numerical simulation of high-temperature smoke erosion for power station boiler superheater tubes[J]. China Chemical Industry Equipment(中国化工装备),2017,19(3):38-43.
[16] LIU Xiaoxin(刘小鑫),CHEN Wangsheng(陈旺生),MEI Dan(梅丹),et al. On the erosion situation of the dust-removing system of the sintering machine tailing[J]. Journal of Safety and Environment(安全与环境学报),2014,14(6):121-124.
[17] XIAO Kun(肖琨),WANG Qiang(王强),WANG Xinqun(王信群),et al. Analysis of boiler finishing superheater flow field characteristics with three-dimensional numerical simulation[J]. Industrial Safety and Environmental Protection(工业安全与环保),2011,37(3):6-7,32.
[2] LE Changyi(乐长义). Current status and prospects of foreign supercritical parameter power station boilers[J].East China Electric Power(华东电力),1985(11):65-71.
[3] ZHANG Lixin(张立新). Improving the influence of steam parameters on the economics of thermal power units[J]. Architectural Engineering Technology and Design(建筑工程技术与设计),2016(19):2427.
[4] YAO Yanqiang(姚燕强). Research of SC/USC coalfired power generation technology[J]. Huadian Technology(华电技术),2008,30(4):23-26.
[5] WANG Dajiang(王大江),ZHU Jian(朱健). Failure analysis of blast furnace high temperature superheater tube blasting[J]. Hot Working Technology(热加工工艺),2014,43(18):223-224,229.
[6] QING Li(卿黎),ZHANG Shengyue(张胜跃),ZHANG Yudong(张宇栋),et al. Failure mode analysis for the pressure-bearing components of the power-generating boiler[J]. Journal of Safety and Environment(安全与环境学报),2016,16(4):17-22.
[7] DONG Yuliang(董玉亮),LI Yaqiong(李亚琼),WANG Zhenhe(王珍和),et al. Safety evaluation on fuel-fired power plant based on evidence theory[J]. Journal of Safety and Environment(安全与环境学报),2010,10(3):179-183.
[8] YANG Zhen(杨震). Mechanism for utility boiler tube failure and measures to improve reliability[J]. Boiler Technology(锅炉技术),2001,32(12):1-7.
[9] LI Zhenggang(李正刚),WANG Zhiwu(王志武),ZHAO Bo(赵博),et al. Statistical analysis for four tubes leakage failure of power plant boiler[J]. Heat Treatment of Metals(金属热处理),2007,32(S1):36-39.
[10] LI Zhongshan(李忠善),ZHU Changyu(朱昌煜),LI Zhigang(李志刚). Application of multistage anti-wear device in 480 t/h circulating fluidized bed boiler[J].Inner Mongolia Electric Power(内蒙古电力技术),2010,28(3):50-51.
[11] CHEN Baokang(陈宝康). Theoretical and experimental research on monitoring and optimizing soot blowing of heating surface boiler in power station boiler(电站锅炉受热面污染监测及优化吹灰的理论与实验研究)[D].Baoding:North China Electric Power University,2004.
[12] MA Jianguo(马建国). Analysis on the influence of boiler operation and management on the wear of low temperature heating surface[J]. Ningxia Electric Power(宁夏电力),2009(S1):225-227,236.
[13] YING Mingliang(应明良),YU Ji’an(俞基安),JIN Di(金涤),et al. Erosion calculation and residual life forecast of enclosure wall tube's elbow[J]. Zhejiang Electric Power(浙江电力),2006(4):14-17.
[14] RAY A K,TIWARI Y N,CHAUDHURI S,et al. Remaining life assessment of service exposed reheater and superheater tubes in a boiler of a thermal power plant:high temperature materials and processes[J]. High Temperature Materials&Processes, 2002, 21(1/2):109-122.
[15] JING Xin(景新). Numerical simulation of high-temperature smoke erosion for power station boiler superheater tubes[J]. China Chemical Industry Equipment(中国化工装备),2017,19(3):38-43.
[16] LIU Xiaoxin(刘小鑫),CHEN Wangsheng(陈旺生),MEI Dan(梅丹),et al. On the erosion situation of the dust-removing system of the sintering machine tailing[J]. Journal of Safety and Environment(安全与环境学报),2014,14(6):121-124.
[17] XIAO Kun(肖琨),WANG Qiang(王强),WANG Xinqun(王信群),et al. Analysis of boiler finishing superheater flow field characteristics with three-dimensional numerical simulation[J]. Industrial Safety and Environmental Protection(工业安全与环保),2011,37(3):6-7,32.
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