ABSTRACT
This chapter covers the technology for waste heat recovery including practical approaches to boiler efficiency improvement and other concepts for utilizing the recovered energy from flue gasses. If waste heat can be utilized in the boiler itself, a considerable advantage is gained by the fact that it is a self-controlling process requiring simple or no controls to regulate its application. If this same energy were to be used in a plant or building, it would be supplying a demand which would vary from the typical boiler operation and need additional controls. The dry gas in the flue gas is formed from the combustion of carbon to carbon dioxide plus nitrogen which does not take part in the combustion process and any excess air above and beyond the amount needed for combustion. Different terminologies have developed over the years in different industries referring to heat recovery process.
