Accident Handling 33: What are the common faults of the under-bed ignition system in circulating fluidized bed boilers?

Common faults of the under-bed ignition system in circulating fluidized bed boilers: failure to ignite, no flame generation.

For the bottom oil gun system in circulating fluidized bed boilers, the main faults include: the flame detector failing to detect a flame signal even when there is one from the oil gun, the oil valves getting stuck, and the high-energy ignition gun getting stuck or unable to be retracted； The insulation layer of the ignition air duct comes off, the ignition air duct turns red or even collapses; the oil gun fails to ignite due to poor oil quality or water entering the oil ； Poor atomization of the oil occurs due to inadequate adjustment of the air flow, improper installation of the oil gun’s atomizing elements, abnormal oil pressure, as well as incomplete combustion resulting from a lack of oxygen in the oil gun; this can even lead to explosions in the ignition air ducts. When the oil gun is in operation, the operators must strictly follow the oil ignition procedure; they must not use methods such as shielding or short-circuiting to bypass certain ignition conditions and thereby lose safety protections. Pay close attention to the temperature values displayed at various measurement points in the ignition air duct, to prevent a sudden rise in the surface temperature of the insulation layer throughout the duct, which could lead to thermal stress and resulting peeling, collapse, or heating up of the insulation. Strictly adhere to the purging time; it is prohibited to allow large amounts of oil to accumulate in the ignition air duct, as this could lead to secondary combustion or other serious accidents such as explosions.

For the bottom oil gun system in circulating fluidized bed boilers, the main faults include: 1. The flame detector fails to detect a flame signal even when there is a flame in the oil gun; the various oil valves get stuck; and the high-energy ignition gun gets stuck or cannot be retracted； The insulation layer of the ignition air duct comes off, the ignition air duct turns red or even collapses; the oil gun fails to ignite due to poor oil quality or water entering the oil ； 2. Poor atomization of the oil occurs due to inadequate adjustment of the air flow rate, or improper installation of the oil gun’s atomizing element; this leads to abnormal oil pressure and poor atomization. As a result, the oil burns incompletely due to lack of oxygen, which can even cause an explosion in the ignition air duct. 3. When the oil gun is in operation, the operators must strictly follow the oil ignition procedures; they must not use methods such as shielding or short-circuiting to bypass certain ignition conditions and thereby lose safety protections. Pay close attention to the temperature values displayed at various measurement points in the ignition air duct, to prevent a sudden rise in the surface temperature of the insulation layer throughout the duct, which could lead to thermal stress and resulting peeling, collapse, or heating up of the insulation. Strictly adhere to the purging time; it is prohibited to allow large amounts of oil to accumulate in the ignition air duct, as this could lead to secondary combustion or other serious accidents such as explosions.

1. The oil quality is substandard; the filters and atomization elements are not cleaned properly, resulting in unstable oil flow and poor atomization performance. 2. The oil inlet valve and oil return valve are stuck and cannot be opened. 3. The electronic lighter fails to ignite or does not ignite at all. 4. If the flame detector fails to detect a flame, ignition must be performed manually at the location. 5. The oil gun propulsion test failed (stalling). 6. The ratio of ignition air to mixed air is not optimal, resulting in unstable temperature rises in the air chamber. 7. During ignition, poor atomization of the oil gun causes a sharp rise in the temperature of the air chamber, resulting in the slag tube (the air chamber section) being burned and deformed or exploding.