Industrial boiler start-up and shutdown are systematic and standardized operating processes,operators should focus on controlling safety hazards,ensure that the equipment is put into operation smoothly and out of operation safely.

一.Start-up

1.Pre Star-tup Inspection

Before starting the industrial boiler, it’s important to conduct a thorough inspection to make sure everything is normal.

Begin by checking the valves and connections for any signs of leaks or corrosion, as these can compromise the system’s safety and efficiency.

Next, confirm that the fuel supply is adequate and functioning properly to avoid interruptions during operation.

Lastly, verify that the water level is at the correct level; low water levels can cause the boiler to overheat, which risks damaging the system.

2.Operating Procedures

  1.Start the circulating water pump, run for 5—10 minutes.

  2.Start the forced draft fan and induced draft fan, adjust the fan speed,form a slight negative pressure in the furnace,ensure air circulation in the furnace.

  3.Start the feed water pump,slowly feed water to the boiler.

  4.Start the furnace purging program, keep the fan running continuously, and the purging time shall not be less than 5 minutes (After purging, do not close the fan, maintain the furnace negative pressure)

  5.The operator wears protective equipment,stands in a safe position, away from the furnace observation port.Turn on the igniter,confirm the igniter produce stable sparks or flames.

  6.Slowly open the fuel valve, send fuel into the furnace,observe the flame color in the furnace,the normal flame is light blue or orange.

  7.Control the furnace temperature raising rate at 50—80℃/h to avoid sudden rise and fall of the furnace body temperature.As the furnace body temperature rises, the pressure in the boiler gradually increases. Control the pressure raising rate at 0.05—         0.1MPa/h

  8.When the boiler pressure rises to 0.1—0.2MPa, open the superheater vent valve to discharge the condensed water in the superheater.After the condensed water is drained, close the vent valve.

3.Operation Monitoring After Startup

Water level: Check the water level every 10—15 minutes, avoid water shortage or water overflow.

Pressure:If the pressure is too high, the safety valve should automatically lift to discharge steam. If the safety valve does not lift, manually open the vent valve to release pressure.If the pressure is too low,increase fuel supply.

Temperature: Monitor the furnace body temperature and steam temperature to ensure the temperature is stable at the rated value.

Equipment operating status: Furnace and pipeline,auxiliary equipment like blower, induced draft fan, water supply pump.Safety devices like safe valve,pressure controller and temperature controller.Electrical system

like electrical lines and motors.

4.Abnormal Situation

Lack of water:Stop fuel supply,close the main steam valve, stop boiler operation.

Full of water:Open the blowdown valve to drain water, reduce the water level to the normal range.

Furnace flameout:Close the fuel valve, re-purge the furnace, and re-ignite after checking the cause of flameout.

Pipeline leaking:Start the emergency shutdown procedure, cut off fuel and power, organize personnel to evacuate.

二.Shutdown

1.Normal Shutdown

Operating Procedures

  1.Gradually reduce fuel supply,turn down the valve for gaseous fuel, reduce the delivery volume for liquid fuel, stop coal feeding for solid fuel.

  2.Observe the changes of steam pressure and temperature,maintain the water level within the normal range.

  3.When the boiler load drops below 10% of the rated load,stop fuel supply,keep the forced draft fan and induced draft fan running continuously to purge the residual combustible gases in the furnace and flue.

  4.During purging, observe the flue gas emission, confirm that the flue damper is fully open without blockage or air leakage. After purging is completed, turn off the forced draft fan, induced draft fan and flue damper.

  5.When the boiler pressure drops below 0.1MPa, open the vent valve and blowdown valve to slowly discharge the steam and a small amount of water in the boiler.

  6.During the cooling process, check the tightness of the furnace body and pipelines every 30 minutes.

  7.Turn off the power supply of all electrical equipment of the boiler, including the control box and motor.

  8.Open the blowdown valve to discharge scale and impurities in the boiler,check safety devices, instruments, valves etc.

2.Emergency Shutdown

Operating Procedures

  1.Immediately press the emergency shutdown button to quickly cut off fuel supply (automatically close the main fuel valve and fuel delivery pump)

  2.Cut off the power supply of all electrical equipment of the boiler at the same time, stop the operation of all auxiliary equipment such as forced draft fan, induced draft fan, feed water pump and circulating water pump.

  3.Continuously observe the changes of furnace body pressure and temperature to ensure that the pressure and temperature drop slowly.

  4.Conduct a comprehensive inspection of the boiler equipment, focusing on the furnace body, pipelines, safety devices, electrical system

  5.After emergency shutdown, if the boiler needs to be restarted, it must be implemented in accordance with the cold start process, and direct startup is strictly prohibited.

Conclusion

The safe and stable operation of the boiler is related to the normal production of the enterprise, and every operating requirement is strictly implemented to provide a reliable guarantee for the development of the enterprise.