Sudden stop of the exhaust fan

Please specify what type of device; there are many exhaust fans. Under normal circumstances, proceed with recovery immediately by turning on direct discharge; enabling a backup unit is also an option.

The last edit to this post was made by chengkang on 2010-7-21 at 10:06. 1. Phenomenon: 1.1 The alarm bell sounds, the current of the tripped motor returns to zero, and the corresponding indicator light for the tripped motor turns on； 1.2 In the event of a fault and tripping of a single induced draft fan, the supply fan and the primary fan on the same side will also trip; when the RB protection activates, the FSSS will automatically select to trip Mill E or Mill D ； 1.3 Positive pressure in the furnace chamber ； 1.4 As the steam temperature, steam pressure, and load decrease, the drum water level first drops and then rises ； 1.5 Both induced draft fans tripped due to faults; the furnace’s MFT protection activated, the steam turbine tripped, and the generator’s reverse power protection triggered, resulting in disconnection. 2. Cause: 2.1 Motor failure, electrical protection activated ； 2.2 Thermal protection activation of the exhaust fan ； 2.3 Mechanical failure of the exhaust fan ； 2.4 Utility power supply failure ； 2.5 False operation accident button. 3. Key handling points: 3.1 Inject oil to stabilize combustion and prevent the boiler from going out ； 3.2 Immediately increase the load on the fan on the other side, but do not overload that fan ； 3.3 Adjust the air volume and coal feed to the coal grinder in a timely manner to prevent the grinder from becoming overloaded with coal or from shutting down completely ； 3.4 The interlock shutdown of equipment below the induced draft fan on the tripped side shall be correct; otherwise, perform it manually. 4. Treatment: 4.1 Immediately inject oil to stabilize combustion ； 4.2 Exit the machine and furnace coordination control system, and manually adjust steam temperature, steam pressure, water level, and furnace negative pressure ； 4.3 In the event of a trip of the exhaust fan, attempting to restart it immediately is not allowed; check that the equipment downstream of the tripped exhaust fan trips in sequence as required, otherwise manual operation must be carried out ； 4.4 Reduce the coal feeding rate of the operating coal grinder, lower the load to 150 MW, and switch the shaft seal and auxiliary steam supply ； 4.5 Increase the load on the inlet, exhaust, and primary fans on the operating side, to maintain normal negative pressure in the furnace, oxygen levels, and primary air pressure ； 4.6 Close the thermal primary air damper at the exit of the air preheater on the tripped side, as well as the primary air speed cut-off damper of the tripped coal mill, and strive to maintain a high primary air pressure ； 4.7 Check that the flue gas dampers at the inlet of the air preheater on the tripped side, as well as the dampers at the inlet and outlet of the exhaust fan, have been closed; then open the secondary air bypass damper at the outlet of the supply fan ； 4.8 If it is difficult to adjust the drum water level, start the electric pump promptly for adjustment ； 4.9 Feed into the air preheater for continuous soot blowing ； 4.10 Check the cause of the trip; resume operation once the fault is resolved ； 4.11 If the MFT operates, treat it as a fault shutdown.

For the automatic shutdown of the exhaust fan in the hydrogen production converter, the procedure is as follows: when it is detected that the negative pressure in the furnace rapidly turns into positive pressure or fluctuates significantly, it is assumed that the exhaust fan has stopped operating or there is a fault with the instruments. Immediately go outside to check the exhaust fan; if it has stopped working, quickly check whether the fire in the furnace is still burning. If it is still burning, start the backup unit immediately; if the fire has gone out, proceed with an emergency shutdown.