Incident Handling 9: What are the causes of explosions in circulating fluidized bed boilers?

There are design flaws in the boiler, inadequate maintenance leading to operation while it is faulty, and there are also cases of operational errors.

This post was last edited by zdl1966 on 2015-8-9 06:26. 1. The gauge may be malfunctioning. 2. Operational error. The fuel speed and wind speed do not match. 3. The fuel nozzle became clogged; this was not detected, resulting in an excess of fuel gas in the furnace. 4. No inspection was performed before ignition. 5. No purging was carried out before ignition, or the purging was incomplete.

Circulating fluidized bed boilers operate with low-temperature controlled combustion, with a combustion temperature of around 850–950°C. If the bed temperature is kept too low, or coal is added too early, a large amount of unburned coal particles and flammable gases may accumulate in the bed material or flue ducts. In cases of insufficient ventilation, explosions can occur in the furnace, or secondary combustion can take place in the flue ducts and electrostatic precipitators. During ignition, if the oil gun fails to atomize the oil properly, if the air flow is not adjusted correctly, or if there is insufficient oxygen, a large number of oil droplets will accumulate in the ignition air duct. When these droplets reach a certain concentration, and they come into contact with a flame or when the oxygen level reaches a certain threshold, an explosion will occur.