To safeguard boilers against fuel explosion in the furnace, operators must ensure that fuel-rich mixture is not created by the oil accumulate on the floor of the boiler.
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 by the stoiciometric ratio.
One of the reasons for a fuel rich mixture is poor atomization of oil, which results in incomplete combustion. This can lead to unburned oil puddling on the floor of the furnace. During the next startup, the oil accumulated on the hot furnace floor begins to volatize and releases its combustible gases when the operator initiates ignition. Inadvertently the pilot ignites this large accumulation of unburned combustible gases in the furnace, which produces the explosion.
The most effective methods to prevent poor automization is by maintaining the burner. This includes ensuring that the burner oil tips are clean, the oil temperature is correct to ensure adequate atomization, the oil viscosity is within design specifications, and the atomizing steam (or air) pressure and fuel oil pressure are properly adjusted. Ensuring these parameters will ensure that adequate atomization of oil takes place.
Additionally, the operators should be cautious to ensure that any oil accumulation on the furnace floor is highlighted and appropriate corrective actions are initiated.