How is steam generated in a steam boiler?

A steam boiler incorporates a combustion chamber or furnace to burn the fuel and generate heat. The heat generated is transferred to the water to produce steam, the boiling process. This produces saturated steam at a rate that may vary according to the power being burned inside.

The remaining heat in the combustion gases can be evacuated or passed through an economizer, which heats the feedwater before it reaches the boiler to increase efficiency and reduce fuel consumption.