Boiler -Emergency Handling

1. BOILER EMERGENCIES
 Drum level low
 Drum level high
 Any FD fan trip
 Any ID fan trip
 PA fan trip
 DCF trip
Continued…

2. BOILER EMERGENCIES
 Bed temperature too high
 Final Steam temperature too high
 Final Steam temperature too low
 PSH O/L steam temperature high
 Economizer O/L FW temperature high
Continued…

3. BOILER EMERGENCIES
 High positive draught
 High negative draught
 Hot bed material leakage from PA
lines or bed ash drain
 O/L steam pressure too low
 Back fire in PA lines

4. Drum Level Low
 Check BFP discharge header pr. And
start another BFP if required
 Check FW control valves position in
DCS and in field
 Check position of all MOVs and operate
them accordingly.
 Check for any abnormal sound from
furnace.

5. Drum Level High
 Operate IBD as per requirement.
 Check FW control valves position in
DCS and in field.
 Close MOVs of Feed Water station as
per requirement.
 Observe PSH O/L steam temperatures.
 Observe Final steam temperature and if it
starts dropping, close Boiler stop valve
immediately.

6. Any FD fan trip
 Stop coal feeding.
 Reduce load on Turbine according to requirement
 Observe Bed temperature
 Check for reason of tripping
 If the situation diminishes further shut the Boiler
stop valve.
 Take compartments into service one by one and
load the turbine

7. Any ID fan trip
 Cut down air flow by operating FD dampers.
 Slump two compartments.
 Check the load on running fan.
 Reduce load on turbine according to requirement.
 Check for reason of fan tripping.
 Take compartments into service one by one and
load the turbine

8. PA fan trip
 Check that whether all DCF got tripped or not.
Otherwise stop them immediately.
 Reduce the load on turbine according to requirement
 See that the standby fan is started. Otherwise start it
and increase the PA header pr.
 Check PA lines for jamming and clear them
accordingly.
 Take compartments into service one by one and load
the turbine

9. DCF trip
 Check PA header pr. If it is less increase it.
 Increase feeding in other compartments or boiler.
 Check for reason of DCF tripping.
 In case of all DCF tripping, isolate boiler depending
on situation.
 In case of any one DCF tripping, observe final steam
pr. And temperature and if require isolate
attemparator.
 Take burner support according to requirement.
 If the problem persists for longer time and pressure
drops, reduce load on turbine.

10. Bed temperature too high
 Cut down coal feeding to that compartment.
 Increase air flow and PA header pr.
 Check for wind box damper position.
 Constantly observe the wind box pr.
 Charge bed material.
 Check for abnormal sound from furnace.
 Stop the boiler if temperatures still not controlled, bed
height decreases rapidly and abnormal sound is
observed.

11. Final Steam temperature too high
 Take attemparator by – pass into service.
 Reduce feeding in 3rd
, 4th
and 5th
compartments.
 Increase load on boiler.
 Observe the TG inlet steam temperature.
 Reduce the steam temperature in other boiler.
 Check attemparator control valve position in DCS and
in field.
 Ensure that none of drum safety valve has popped.

12. Final Steam temperature too low
 Isolate attemparator and check for passing/opening of
attemparator by – pass.
 Check drum level.
 Observe constantly the TG inlet steam temperature.
 Increase steam temperature in other boiler.
 Increase feeding in 3rd
, 4th
and 5th
compartments.
 Reduce load on boiler.
 If the rate of drop is higher, isolate the boiler
immediately and operate start – up accordingly.

13. PSH O/L steam temperature high
 Increase load on boiler.
 Minimize furnace draught.
 Check the position of overfeed secondary air dampers
and open them.
 Regulate air flow according to requirement.
 Increase bed height.
 Meanwhile confirm that the temperature indication is
correct.(Attemperator flow will increase)

14. Economizer O/L FW temperature
high
 Increase load on boiler.
 Reduce Economizer I/L feed water temperature.
 Minimize furnace draught.
 Check the position of overfeed secondary air dampers
and open them.
 Regulate air flow according to requirement.
 Increase bed height.
 Meanwhile confirm that the temperature indication is
correct.

15. High positive draught
 Confirm that the draught indication is correct.
 Check and control ID fan speed.
 Check ID dampers position.
 Check FD dampers position.
 Check for abnormal sound from furnace.

16. High negative draught
 Confirm that the draught indication is correct.
 Check and control ID fan speed.
 Check wind box dampers position.
 Check ID dampers position.
 Check FD dampers position.
 Check APH online and by – pass dampers position.

17. Hot bed material leakage from PA lines
or bed ash drain/Back fire in PA lines
 Observe bed temperatures constantly and charge bed
material if required.
 Cut down coal feeding to that compartment, let the
bed temperature be drop down and close wind box
damper.
 Check that air damper of that line is open.
 Clear that line if the leakage is from vertical portion.
 If the leakage increases further, stop the boiler.

18. O/L steam pressure too low
 Check bed temperatures and increase coal feeding
accordingly.
 Check for jamming of coal hopper, PA lines and clear
them accordingly.
 Take burner support if required.
 Ensure that DCF chain is rotating(no shear pin failure).
 Ensure that air flow is sufficient.
 Drain bed material slowly, if bed height is more.
Continued…

19. O/L steam pressure too low
 Check for passing or malfunctioning of Boiler safety
valves.
 Check for abnormal sound from furnace.
 Check for malfunctioning of Dumping control valve
and PRDS control valve.
 Check and increase the feed water temperature.
 If pressure goes down further and frequency drops,
reduce load on turbine.

20. TURBINE
EMERGENCIES
 Turbine trip
 Load throw off
 UAT trip
 CEP trip
 Hotwell level high
 Hotwell level low
 Vacuum drop Continued…

21. TURBINE
EMERGENCIES
 Fire/smoke at turbine area
 Turning gear trip
 Oil temperature high
 Bearing temperature high
 Bearing vibration high
 Steam pressure high after first stage

22. Turbine trip (sharing mode)
 Safeguard the running unit (Reduce load on turbine if
required and Ensure that CWP, BFP, ACWP, CT Fan,
Inst.air compressor are running)
 Cut down proportionate coal feeding in boilers.
 Observe boiler drum level and take steps accordingly.
 Control steam pressure by operating PRDS and
dumping control valves.
 Start AOP, JOP, TTG.
 Investigate the reason of tripping.
 Don’t switch on PEF until unless it is reset and load

23. Turbine trip (Non – sharing mode)
 Safeguard the running unit (Reduce load on turbine if
required and Ensure that CWP, BFP, ACWP, CT Fan,
Inst.air compressor are running)
 Take grid supply after ensuring Generator breaker has
opened.
 Observe boiler drum level and take steps accordingly.
 Control steam pressure by operating PRDS and
dumping control valves.
 Ensure that extraction MOV is closed.
Continued…

24. Turbine trip (Non – sharing mode)
 Start AOP, JOP, TTG.
 Investigate the reason of tripping.
 Don’t switch on PEF until unless it is reset and load
shedding is switched – off.
 Maintain hotwell level and ensure that CEP is running.

25. Load throw – off
 Check turbine speed, if it is at alarming level and is
increasing further, trip the turbine.
 Observe drum level.
 Slump compartments in boiler according to the amount
of load thrown off.
 Take PRDS into service if both extractions are out of
service.
Continued…

26. Load throw off
 Regulate dumping steam according to dumping header
temperature and condenser vacuum.
 Check for reason of load throw – off.
 If the load throw – off occurs because of any breaker
opening, check thoroughly before closing it.

27. UAT trip
 Observe the hotwell level and condenser vacuum and
if the power is not resumed within short time, trip the
turbine and isolate all steam inputs to condenser.
 Reduce load on running turbine if required.
 Observe CW and turbine oil temperatures.
 Check for reason of UAT tripping and charge all
remaining feeders/MCC keeping the faulty
feeder/MCC isolated.

28. CEP trip
 Ensure that standby pump has taken over.
 Check for reason of tripping.
 Check hotwell level and if it is low, take make – up
water into hotwell.
 Open hotwell re – circulation valve fully.
 Check for passing of condensate valve B or C and
isolate them accordingly.
 If the tripping is because of overload, check for
mechanical jamming of pump.

29. Hotwell level high
 Ensure that standby pump has taken over.
 Check running CEP(s) load.
 Close hotwell re – circulation valve.
 Check position of condensate valve B or C and
operate them accordingly.

30. Hotwell level low
 Take make – up water into hotwell.
 Open hotwell re – circulation valve fully.
 Check for passing of condensate valve B or C and
isolate them accordingly.

31. Vacuum drop
 Check gland steam pressure.
 Check CW temperatures.
 Check hotwell level.
 Check the running ejector.
 Check for air ingress from all vacuum related lines
and valves.
 Cut down dumping steam.
 Charge standby ejector if the rate of drop is more.
 If the rate of drop is more, reduce load on turbine.

32. Fire/smoke at turbine area
 Ensure that vapour extraction fan is running if the fire
is because of oil leakage from any bearing.
 Use CO2 fire extinguisher in case of minor oil and
electrical fires. Don’t use water or other type of fire
extinguishers.
 In case of major fire, first isolate the source (trip the
turbine and isolate generator from electrical circuit)
and then quench it.

33. Turning gear trip
 Ensure that jacking oil pressure is sufficient.
 Ensure that lube oil pressure is sufficient.
 Put turbine on manual barring gear.
 Check for reason of turning gear trip.

34. Oil temperature high
 Ensure that the CW temperatures are not on higher
side (All CT fans are running).
 Stop TOPP if it is running.
 Check oil level in Main oil tank.
 Provide external cooling arrangement.
 Ensure that oil temperature controller is working.
 If the bearing temperatures start increasing, trip the
turbine immediately and provide external cooling
arrangement for bearings.

35. Bearing temperature high
 Charge bleed steam.
 Check oil temperature.
 Check oil level in Main oil tank.
 Ensure proper oil flow to the bearing.
 Check axial shift.
 Provide external cooling arrangement.
 Reduce load on turbine if temperatures goes on
raising.

36. Bearing vibration high
 Confirm that the signal is correct and is matching with
Bently – Nevada vibration monitoring system.
 Confirm the same in field physically.
 Ensure proper oil flow to the bearing.
 Check casing temperature difference.
 Reduce load on turbine if vibration goes on raising.

37. Steam pressure high after first stage
 Reduce load on turbine if pressure is at alarming
level.
 Reduce bleed steam.
 Check control valve position and turbine speed.

38. Other emergencies
 BFP trip
 CWP trip
 Inst. Air compressor trip

39. BFP trip/Discharge header pr. low
 Ensure that standby pump has taken over.
 Monitor drum level (Increase dumping CV opening, if
drum level starts dropping).
 Reduce load on TG.
 Investigate the reason for tripping.
 If both the BFP tripped and standby has not taken
over because of any common problem, trip both TG
and box – up the boiler.

40. CWP trip/ Discharge header pr. low
 Ensure that standby pump has taken over.
 Monitor condenser vacuum.
 Reduce load on TG.
 Cut down dumping.
 Investigate the reason for tripping.
 If both the CWP tripped and standby has not taken
over because of any common problem, trip both TG
and isolate all steam inputs to the condenser.

41. Inst. Air compressor trip/Inst. Air pr. low
 Ensure that standby compressor has taken over.
 Check conservair O/L air pr.
 Monitor boiler drum level, furnace draft, CWP
discharge header pr., FD control dampers position
constantly.
 Ensure that running compressor is fully loaded.
 Check for choking of dryer filters.
 Ensure that both dryers power supply is ON.
 Check for leakages in the system.