一、前言利用换热器回收烟气余热来预热燃烧用空气,是工业炉降低燃料消耗,节约能源的有效措施。在出炉烟气温度一定条件下,空气预热温度越高,烟气余热回收越充分,节约燃料也就越多,但是,随着空气预热温度的提高,换热器需要的传热面积迅速增加,投资费用相应增多。因此,在设计换热器时,合理地选取空气预热温度 Preface The use of heat exchanger to recover flue gas waste heat to preheat the combustion air is an effective measure to reduce fuel consumption and energy conservation in industrial furnaces. In the flue gas temperature released under certain conditions, the air preheating temperature is higher, the flue gas heat recovery more fully, saving more fuel, but with the air preheating temperature, the heat exchanger required heat transfer area rapidly Increase, a corresponding increase in investment costs. Therefore, in the design of heat exchanger, a reasonable choice of air preheating temperature