Rotary Air Preheater Air Leakage Factor Analysis And Countermeasures

The air preheater, one of the most important auxiliary equipments in utility boiler of the power plants, is heat-exchange equipment that makes use of residual heat of gas to heat the air needed by the boiler combustion. The air preheater, working in the area where gas temperature is the lowest in the boiler, can recover gas heat and lower the exhaust gas temperature, which can improve efficiency of the boiler. Rotary air preheater, the mainly rotary air preheater whose heat surface can rotate, is prevailing in the boiler with capacity being 300MW or more and some boilers with capacity being 200MW.The rotary air preheater, during the working process, due to its structure, will have some troubles, one of which is the air leakage. The air leakage rate of the rotary air preheater is about 8 percent. When the working condition is abnormal, it can achieve 20 percent, which will decrease efficiency of the boiler. Therefore, it is necessary to solve the air leakage troubles for the power plant. This article begins with the present situation of rotary air preheater, introduces the harm brought by the air leakage of air preheater. The article simply illustrates all kinds of troubles for the rotary air preheater, including low temperature corrosion, ash deposit, secondary combustion, abrasion and so on. Detailed questions about the air leakage are discussed.Based on the former research, through the above analysis and the mechanism of leakage, the article analyzes the reasons that cause the rotary air preheater to leak and the locations where it will leak usually.Through the analysis for the mathematical model of the air...