Heat transfer within steam boiler can be performed by three ways and by their combination; radiation, conduction, and convection. Optimizing heat transfer should be done to maximize efficiency of steam boiler. The followings are the ways to optimize heat transfer:
1. Control excess air
Composition of excess air should be controlled, if excess air is too much will effect temperature of flue gas low because of cooling from excess air, but on contrary if amount of excess air is too low will cause flame temperature is high.
2. Keep clean boiler tubes
Tubes receive heat from combustion furnace by radiation and heat is distributed to all of surface metal tubes by conduction. The presence of soot, ash and scale will obstruct heat transfer because they are poor conductor. Any deposit on outside surface tubes can be cleaned by soot blower, while any scale in inner side tubes can be prevented if water treatment is undertaken well.
3. Keep optimum flue gas and feedwater
Feedwater should be treated free from sludge and scale to ensure water can receive good heat transfer and can flow with a certain velocity. Optimum flue gas can be taken by doing routine maintenance and choose optimum fuel.