This problem should be like this. It should be a pulverized coal furnace.
Coking and slagging will naturally be difficult. A certain amount of coke must have fallen. so this is a continuous question,
The positive pressure at this time is due to the fact that when a large piece of coke slag falls, at the same time there is a certain amount of ash flies burned on the block of coke. As the coke block falls, these ashes fly into the furnace under the action of negative pressure. At this time, the flame burning in the upper part of the burner is affected by these fly ash and cannot mix with air. as well as normal. Part of the combustion stops, and the furnace The fire weakens and can even extinguish the fire for small furnaces, but the effect of the fly ash quickly fades, and this part of the combustion resumes instantly, making thus unstable combustion, thereforeforming a positive pressure fire, which is equivalent to deflagration.
If the slag falling into the furnace is intermittent, this deflagration will occur intermittently,