某600 MW超临界机组空气预热器两侧排烟温度偏差问题分析OA

The exhaust gas temperature of APH(air preheater)is an important parameter affecting the safety and economy of power station boiler.In order to diagnose the reasons for the deviation of the exhaust gas temperature on APH of a supercritical unit,based on the heat transfer equilibrium equation and the corrected calculation of the exhaust gas tempera-ture,the influence of key parameters such as inlet flue temperature,inlet air temperature,in-let flue gas flow rate,inlet air flow rate,and air leakage rate on the exhaust flue temperature was analyzed by combining theoretical analysis and calculation.The resistance characteristics of each system in the tail flue were analyzed by on-site flue resistance test and damper regula-tor test.The results of calculation and analysis show that:In the APH system,the flue gas volume on side A is 1.164 times the inlet air volume on that side,while on side B it is 1.297 times the inlet air volume on that side.The discrepancy in flue gas volume between the two sides of the air preheater is the main factor affecting the deviation in exhaust gas tempera-ture.With the flue gas damper opening on side B set at 35％,the flue gas flow rates on both sides become nearly equal,and the resistance of the denitrification system of side A is higher than that of side B by 327 Pa.The abnormal resistance of the denitrification system is the root cause of the deviation of the exhaust gas temperature.