Boiler feed pumps start up & shutdown procedure






                    


                 Start-up Pre-check lists

  • Ensure Boiler feed pump is not in permit for maintenance works
  • Ensure all the maintenance activities on pumps are completed
  • Ensure equipment are normalized from electrical & mechanical side
  • Ensure Boiler feed pump is free from obstacles
  • Ensure enough lighting or illumination is available there
  • Ensure pump coupling is well guarded by robust coupling guard
  • Ensure Pumps local field instruments like pressure gauges, switches, vibration sensors, DP gauges are healthy
  • Ensure coupling is free to rotate

Starting procedure:

Start permissive (interlocks)

  • Ensure deaerator level is normal
  • Ensure feed pumps suction valves is open
  • Ensure cooling water line & outlet valves to bearings & mechanical seals are open and also water is circulating through the lines.
  • Ensure bearing temperatures are normal
  • Ensure bearing vibration showing DCS is zero
  • Ensure there is no alarm exists for strainer DP (differential pressure)
  • Ensure suction pressure is normal
  • Ensure discharge valve of the pump is closed
  • Ensure minimum recirculation valve or ARC valve is in open condition
  • Ensure balance leak off line valve to deaerator is open (In some valves are not provided to balance leak off line)

Start-up sequence

  • Take clearance from electrical & field person to start the pump
  • After getting the clearance from both the team, start the pump by giving minimum set point 80% if it is VFD driven.
  • Once the pump started, ensure pump will attain minimum 40% RPM in just 10 seconds (in case of journal bearing pumps).For non-journal bearing pumps speed ramp up time is not recommended specifically.
  • During speed ramp up check bearing vibrations & temperatures are normal.
  • Ensure pressure in the discharge pressure gauge is increasing slowly & has reached rated pressure at rated speed.
  • Then check the vibration, bearing temperatures & sound from pump.
  • Check & ensure the correctness of balance leak off line pressure
  • Wait for stabilization of the pump, once the pump attained rated parameters, check the motor current, temperature & vibrations & ensure they are within permissive limit.

Also recheck pump bearings vibration, temperatures & any abnormal sound from pump.

Pump normal shutdown procedure

  • For VFD driven pumps reduce the pump speed to 80% (for start delta driven pumps speed cannot be reduced)
  • Close the pump’s discharge valve
  • Then stop the pump

Do not’s for Boiler feed pumps

  • Do not rotate the pump in reverse direction, reverse direction leads the seize of pump
  • Don not run the pump if its suction water temperature is more than design/required
  • Do not operate the pump at less than 80<% load for long time to avoid damage to the bearings
  • Do not close the auto recirculation line valve
  • Do not close the balance leak off line valve (if provided)
  • Do not stop the pump with discharge valve open
  • Do not throttle the suction valve of the pump at lower load, can throttle discharge valve

 

 For related articles read

powerplant & calculations

 

 

 

 

 


No comments:

Post a Comment

Hi all,
This article is written based on practical experience..If liked, share with others, or any suggestions leave in comment box.

Reasons for Priming, Foaming and carryover in Boilers

  Priming: 1. What do you mean by the term Priming? Priming means carryover of water particle in the steam 2. What are the reasons for...

Frequently visited posts