Boiler Air Heaters are fitted for main reasons below: Air heaters also form a convenient way to warm up a standby boiler before initial firing. However, the effects of dew point corrosion and fouling in smoke tube air heaters should be taken into account when designing the heat absorption limit. The amount of heat to be removed from the flue gas should have a limit. For water tube boilers gas air heaters are only considered where the temperature at the inlet to economizer is greater than 200oC. Due to greater heat transfer efficiency between gas/water economizers are preferred to gas/air exchangers. At low loads, gas/air heaters should be bypassed to keep uptake temperatures as high as possible |