This website uses cookies. By continuing to browse, you are agreeing to our use of cookies as explained in our, Cookies Policy.

To ensure safe boiler operations, in between burner trips, complete air purge should be allowed to ensure fuel-rich atmosphere is not formed.

One of the most dangerous situations in the operation of a boiler is that of a fuel explosion in the furnace. A fuel rich mixture is one of the major reasons for a fuel explosion to take place in the boiler. Such a fuel rich mixture is formed when the quantity of fuel in an air fuel mixture is higher than that required as per the stoiciometric ratio.

A fuel rich mixture can be potentially created after some problem in the combustion causes a burner trip. For example, should the oil tip of the burner be plugged with some debris, the oil spray pattern and automization will be disturbed. This will lead to an unstable flame which can also lead to a flame failure and the burner will trip. The operator will most likely attempt to relight the burner without investigating the cause of the flame failure and with each successive attempt to relight the burner, more oil will be sprayed into the furnace.

Soon the oil on the hot furnace floor will begin to volatize and will release its combustible gases when the operator initiates another trial for ignition. The pilot then ignites the large inventory of unburned combustible gases in the furnace, which could prove to be explosion.

In a manually controlled burner (or when an automatic burner is set in the manual mode) such circumstances can be prevented primarily by a vigilant operator and adherence a robust standard operating practice. Firstly, in case of a boiler trip the reason for the trip should be investigated and message relayed to the appropriate authorities. Secondly, in between trips, proper and complete air purge should be ensured. This air purge will evacuate the accumulated unburnt fuel vapors, ensuring that the atmosphere inside the furnace is not fuel-rich. These simple measures will ensure safe and smooth operation of the boiler.