HRSG uses heat of exhaust gas from turbine and gas engine to generate steam.
The boiler consists of 4 main parts: economizer that heats the feed water, evaporator that evaporates the water, drum super heater that separates steam and water, and feed water preheater.
Heat Recovery Steam Generator (HRSG)
![Exhaust Heat Boiler](../images/principle04_01.png)
Principle
![Principle](../images/principle04_02.png)