回转式空气预热器受热面设计及校核计算

发布时间：2019-01-19 19:40

【摘要】：空气预热器布置于整个锅炉热力系统的尾端,是电站锅炉的重要辅助设备。而其自身也有着结构紧凑、提高换热效率、使用寿命长、耐腐蚀性好的特点,因此在现代电厂锅炉中得到广泛的使用。当在锅炉系统中引入SCR脱硝装置后,空气预热器会出现严重的硫酸氢氨堵塞现象,大大降低了空气预热器的换热效率,进而影响到整个系统的经济效益。因此需要对空气预热器进行改造以及新的性能计算。为了更好地对空气预热器进行结构改造,也为了减轻加装SCR脱硝装置后空气预热器所受到的硫酸氢氨堵塞,需要对空气预热器进行设计计算,对新工况条件下的空气预热器的受热面高度进行设计计算。同时为了防止和预测硫酸氢氨固体形成,需要针对不同煤种和工况的回转式空气预热器校核计算,确定不同工况下空气预热器烟气侧的工作温度和空气工质的工作温度。通过对计算模型的分析,结合现行的热力计算标准,对电站锅炉三分仓回转式空气预热器的热力计算进行了研究,设计出空气预热器的设计及校核流程图,依次改变初始条件,对空预器在各种工况条件下热力过程进行了计算。从煤种、煤质、进口空气温度以及烟气进口温度等方面分别进行了计算研究,得到了空气预热器出口参数在不同工况条件下的变化情况。计算结果可对SCR改造后空气预热器面临的低温腐蚀、漏风、堵塞等问题提供改造依据,同时还对电厂选择合适的送风温度以及电站锅炉的安全、经济运行具有重要的工程价值。
[Abstract]:The air preheater is arranged at the end of the whole boiler thermal system and is an important auxiliary equipment of the utility boiler. Because of its compact structure, high heat transfer efficiency, long service life and good corrosion resistance, it is widely used in modern power plant boilers. When the SCR denitrification unit is introduced into the boiler system, the air preheater will appear serious hydrogen ammonia sulphate clogging phenomenon, which greatly reduces the heat transfer efficiency of the air preheater, and then affects the economic benefit of the whole system. Therefore, it is necessary to reform the air preheater and to calculate its performance. In order to improve the structure of the air preheater, and to reduce the hydrogen ammonia sulfate blockage of the air preheater after the installation of the SCR denitrification unit, it is necessary to design and calculate the air preheater. The heat surface height of the air preheater under the new working condition is designed and calculated. At the same time, in order to prevent and predict the formation of hydrogen ammonia sulfate solids, it is necessary to check and calculate the rotary air preheater for different coal types and working conditions, and to determine the working temperature of the flue gas side and the working temperature of the air working fluid of the air preheater under different working conditions. Based on the analysis of the calculation model and the current thermodynamic calculation standard, the thermodynamic calculation of the three-point rotary air preheater of the utility boiler is studied. The design and checking flow chart of the air preheater is designed, and the initial conditions are changed in turn. The thermodynamic process of air preheater under various working conditions is calculated. From the aspects of coal, coal quality, inlet air temperature and flue gas inlet temperature, respectively, the variation of outlet parameters of air preheater under different working conditions is obtained. The calculated results can provide a basis for the retrofit of the air preheaters after SCR modification, such as low temperature corrosion, air leakage, blockage and so on. At the same time, it is of great engineering value for the power plant to select the appropriate air supply temperature and the safety and economic operation of the power plant boiler.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM621.2

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