A boiler that has been running for a long time is sure to have soot deposits on its tubes and furnace.
This is especially prominent in boilers using heavy fuel oil for burning. Although fuel will be heated and filtered before combustion, it still contains a lot of impurities. The by-products of combustion as well as imperfect combustion cause soot to form. The soot is deposited on heating surfaces.
During combustion of fuel oil in a steam boiler, hot gases are formed. These hot gases are used to heat up water in boiler to form steam.
With deposits of soot, a lot of heat energy is not able to be transferred to water, but instead is lost through chimneystack. The soot layer acts as a heat insulator for tubes and shells of furnace. The heat is unable to reach water.
This not only causes boiler efficiency to be lowered, but a more serious problem can also occur. The soot can catch fire!
A soot fire can be detrimental to strength of boiler because it can cause serious localized hotspots to occur at tubes. These localized hotspots can even reach temperatures that weaken materials of tubes.
Soot blowers are installed to blow away these soot deposits. Steam is normally used as a medium for blowing away soot.
The operation of soot blowers goes like this:
1. Steam is channeled to soot blower pipeline. 2. The operator of soot blower will open a drain valve to drain off any water in steam. This is to make sure