Fan shutdown operation

It is best not to open the inlet valve of the standby fan, because if the valve behind the standby fan does not close properly, some gas will circulate from the standby fan back to the inlet.

Previously, the company operated three fans simultaneously, and it was very troublesome to switch to an alternative fan when one of them failed. Does any member have a good solution?

Operation for shutting down a fan when fans are connected in series: ⑴ After all preparatory work is completed, open the outlet valve of the fan to 10%. ⑵ Once all preparations are finished, wait for instructions from the supervisor. ⑶ Once normal operation is achieved, inform the dispatch team to notify the coking workshop and the gas workshop so that they can start reducing the load on the fan that is to be shut down. ⑷ Gradually close the inlet of the fan to be shut down (by about 2% each time), reduce the outlet valve opening (ensuring the outlet pressure is higher than the inlet pressure), and adjust the speed so that the speed of the fan remains between 2400–2600 Pa. ⑸After closing the inlet and outlet valves of the fan, set the coupler actuator to zero position, leaving about 5% open at the outlet. ⑹Reduce the speed of the operating fan to between 2600 and 2650 revolutions per minute. ⑺ Set the manual controller for the fan to automatic mode; assign a dedicated person to adjust the coupling actuator. Increase the actuator’s displacement by 2–5 units each time, with a short pause after each adjustment. Stop when the output speed of the coupling reaches 1500 revolutions per minute. Once the fan’s speed stabilizes and all components are functioning properly, increase the actuator’s displacement by 12–15 units at a time to raise the coupling’s output speed to 2500–2650 revolutions per minute. ⑻When the coupling output speed reaches 2400 revolutions per minute, gradually open the fan outlet valve to 50%. ⑼Once the fan speed is stable, slowly open the fan inlet (by 1% at a time) while increasing the fan speed; the speed should remain above 2500 revolutions per minute. Pay close attention to changes in the fan current (it should not exceed 100A). When the inlet valve is opened to 20%, increase it by about 3% each time, but the final opening degree must not be less than 30%. If the amount of gas supplied is low, use a large circulation mode for adjustment, and pay close attention during startup to ensure that the suction pressure before the pre-cooler is less than 2000 Pa. ⑾After startup, pay close attention to changes in various parameters such as the temperature of the motor couplings and the shaft bearings of the fans, the suction force at the front of the machine, the motor current, fan speed, lubricating oil temperature and pressure, as well as the temperature and pressure of the working oil and the vibration levels of the unit. ⑿ Adjust the inlet and outlet valves of the two fans so that their speeds differ by no more than 30 revolutions per minute, and ensure that the current in both fans remains within 3A. ⒀ Once the fans are operating properly, open the drain pipe and purge it. This post was last edited by aishenI on 2009-3-30 12:12]

Are there three more gas blowers operating in series? ? ? ? ? Is it in parallel? I’ve never heard of blowers being connected in series! Moreover, the steps are completely wrong; such a haphazard approach will be misleading! This post was last edited by lhq6388 on 2009-3-30 23:18.]

Shutdown procedure for the blower: 1. Consult the dispatcher and arrange for relevant professionals to be on site； 2. Carry out all the preparatory tasks before starting the blower as required ； 3. Conduct inspections for process, machinery, electrical systems, and instrumentation respectively, and obtain signature confirmation ； 4. After turning on the machine, open the vent pipe and the steam cleaning pipe; use the drain pipe to purge the fan that is about to be started. Once it is satisfactory, close the cleaning pipe and the vent pipe, as well as the drain pipe of the blower ； 5. Open the inlet valve of the blower to be started; once the operation is complete, close the inlet valve and open the outlet valve of the blower to be started to 80% capacity ； 6 The hydraulic coupler of the blower to be started is set to manual adjustment mode ； 7 Upon receiving the start command, the main motor of the fan to be started is activated; once the fan is operating at low speed, its speed is increased gradually ； 8 Slowly open the inlet valve of the fan to be started to 20% ； And slowly close the inlet valve of the fan to be shut down to 20% ； 9 Reduce the speed of the blower that is to be shut down, and gradually increase the speed of the newly started blower ； 10. When adjusting the speed of the two blowers, ensure that the suction force in front of the machine meets the technical requirements; if this suction force is too low, increase the speed of the newly started blower and open its inlet valve wider ； When the suction force in front of the machine is too high, reduce the speed of the blower that is to be stopped and close its inlet valve ； 11 Gradually increase the speed of the fan to be started, and open the inlet valve of that fan to 40% ； 12 Gradually reduce the speed of the fan that is to be shut down, and slowly close the inlet valve of this fan until it is fully closed ； 13 When the speed of the fan to be stopped is below 200 revolutions per minute, cut off the power supply to the main motor of the blower to be stopped ； 14 Once the fan to be stopped has come to a complete stop, close its outlet valve ； 15 Change the adjustment of the fan hydraulic coupling to automatic, and open the drain pipe ； When the bearing temperatures of all the stopped fans have dropped to 40°C and the oil temperature in the oil station has fallen to around 30°C, shut off the cooling water for the oil coolers of those stopped fans and stop the oil pumps ； Steam was used to clean all the drainage pipes of the fan that had been shut down; the relief pipe in front of the rear valve of the fan was opened, and steam was used to clean the fan itself ； 18. After parking for half an hour, turn the engine 180 degrees once; thereafter, turn it 180 degrees every hour, four times in total. Once it is operating normally, turn the engine once per shift. The 19 backup fans should have their drain pipes cleaned once per shift.

If the fan’s inlet is left open, gas leakage can occur. When we started the exhaust fan there, within less than ten minutes the fan room was filled with a strong smell of gas.