Principles for dealing with cracked furnace tubes
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This unit’s heating furnace is equipped with an interlock to shut down the furnace (shutting down the blower and exhaust fan, opening the quick-opening air valves, and activating the flue gas heat bypass). Regarding the principles for dealing with cracked furnace tubes, the furnace is shut down and fire-suppression steam is used; but is this quick-opening damper opened? Why? Please ask the experts to answer.
When it is turned on, the preheater system should be shut down in case of excessive flue gas temperature
Open, switch from forced ventilation to natural ventilation
It must be opened to prevent the formation of an explosive space inside the furnace, and steam is used to displace the oil and gas.
Principles for dealing with cracked furnace tubes: Stop feeding and discharging material, and close the valves; shut down the blower, exhaust fan, and flue gas heat bypass; release fire-suppression steam. Close all combustion nozzles in the furnace as well as all fuel valves. Also, release fire-suppression steam at the bottom of the furnace. In principle, all air dampers should be closed to isolate air.
Cut off the combustible and oxidizing media feeding into the furnace, fully open the flue dampers to extract the material, and gradually introduce fire-extinguishing steam depending on the pressure in the furnace chamber.
If the air inlet valves are not opened fully, and there is inevitably air leakage from the furnace, is there a risk of flash explosion?
The fast-opening air valve should not be used; instead, the furnace chamber should be quickly opened to introduce steam for extinguishing the fire and to isolate it from air as rapidly as possible. Additionally, the direct flue valve has been opened to create negative pressure that draws away the burned smoke as well as the unoxidized or unburned air.
Why open the quick-open damper? At this point, it can be understood as aiming to extinguish the fire quickly by reducing oxygen supply?