Which Is Generally Placed After the Economizer?

Air Preheater is to increase the temperature of the air before it enters to furnace. It is generally placed after the economiser , so the flue gases pass through the economiser and then to the air prehaeater.

Where is the economizer placed?

The economizer is made up of a bunch of horizontal water tubes usually located in the back pass or second pass (after the primary superheaters and reheaters) of the boiler through which the feedwater enters the boiler to absorb residual heat from the exhaust flue gas and transfer it to the steam production cycle.

How does an economizer work on a boiler?

Economizers capture heat from the exhaust flue and return it to the boiler by heating the incoming feedwater. By heating the feedwater, the boiler does not have to expend as much fuel to turn the water into steam. Over the long term, fuel costs are the top expense involved in running a boiler.