非典型进风温度和漏风率状态下锅炉排烟温度修正计算方法

Correction calculation method of boiler exhaust temperature under conditions with atypical inlet air temperature and air leakage rate

针对《电站锅炉性能试验规程》(GB/T 10184-2015)中排烟温度修正计算模型,在非典型进风温度和空气预热器性能状态下对其适用性进行研究,给出修正计算改进模型,并依托某300 MW机组试验结果进行校核计算。结果表明:空气预热器烟气侧漏风率偏离设计值1%以上,进风温度偏离设计值20℃以上时(非典型进风温度条件),GB/T 10184-2015中排烟温度修正计算结果存在较大误差,应将空气预热器漏风率和烟气侧效率引入修正计算;不同电负荷下,试验机组空气预热器烟气侧漏风率较设计值偏大2%~3%,依据GB/T 10184-2015修正计算结果tG15dA1会偏低1.7~2.6℃,该误差值与烟气侧漏风率(AL)呈正比关系;在非典型进风温度边界条件下,空气预热器烟气侧效率目η较基准工况降低1.2%~3.3%,依据GB/T 10184-2015计算结果tG15δA1偏高0~7.2℃,误差值与系统进风温度呈正相关关系。该改进模型不仅消除了修正计算误差,也为诸多电站锅炉热效率精准计算提供了科学指导。

The applicability of the exhaust temperature correction calculation model in the Performance test code for utility boiler(GB/T 10184-2015)is investigated under conditions with atypical inlet air temperature and air preheater performance state.The improved calculation model is given and moreover,the test results on a 300 MW unit are checked by using the improved model.The results show that,when the air leakage rate at the flue gas side of the air preheater deviates from the design value by more than 1%and the inlet air temperature deviates from the design value by more than 20℃(the non-typical inlet air temperature condition),the corrected calculation result of the exhaust temperature according to the GB/T 1018-2015 has relatively large error.The air leakage rate and the flue gas side efficiency should be introduced in the correction calculation.At different electricity loads,the air leakage rate at the flue gas side of the air preheater of the test unit is 2%〜3%larger than the design value.According to the corrected calculation results of GB/T 10184-2015,the Zgissai will be 1.7-2.6℃ lower.This error value is proportional to the flue gas side air leakage rate(Al).Under atypical boundary conditions(the inlet air temperature deviates from the design value by more than 20℃),the air preheater flue gas side efficiency ηis 1.2%~3.3%lower than the reference condition.According to the GB/T 10184-2015,the calculation result feissAi is 0-7.2℃higher,this error value is positively correlated with the system inlet air temperature.The modified calculation model proposed in this paper not only eliminates the correction calculation error,but also provides scientific guidance for the accurate calculation of thermal efficiency of many utility boilers.