There some things which need to be considered to carry out combustion system of steam boiler. They are control of air supply, mixing of air and fuel, also temperature and time required for combustion. At this time will discuss the importance of air temperature for the combustion process.
Air temperature should be set to perform complete combustion. If any changes of air temperature will influence the amount of required air temperature to be supplied into steam boiler and amount of excess air. Practically, there is not fix rules to set air temperature. If amount of excess air is high will lead to heat loss, high temperature in stack and will decrease efficiency of overall boiler. But on contrary, if amount of excess air is too low will impact to incomplete combustion, wasted fuel, and too much soot attached on the surface of pressure part.
Practically, to perform efficiently burner is adjusted initially at amount of excess air 15%. The lower temperature of air will make the greater amount of excess air, and vice versa. In every increase of air temperature 40 F will influence the required excess air decrease approximately 5%. The outside temperature will always changes in day and night, this condition will influence to the changes of air temperature in the furnace. So, equipment analyzer for combustion is required to help operator maintain efficiency of steam boiler on top level.