1. Absorb the heat of low-temperature flue gas, reduce the exhaust gas temperature, reduce smoke loss and save fuel.
2. Since the feed water is heated in the economizer before entering the steam drum, the heat absorption of the feed water on the heated surface is reduced, and the economizer can be used instead of the partially evaporated evaporating heating surface.
3. The temperature of the feed water is increased. When entering the steam drum, the wall temperature difference is reduced, the thermal stress is correspondingly reduced, and the service life of the steam drum is prolonged.