Training on Boiler Light-uppppppppp R3.pptx

Training on _Boiler Light-
up
Part1

Objectives and other details of modules
Duration – 90 + 75 minutes
Training on _Boiler Light-up
Power point Presentations
Reading Material
Objective
At the end of the session participants will be able to:
• Understand and develop comprehensions about:
• Initial checks for boiler Start up
• Steps involved in Boiler Cold Start up
• Operating procedures & sequence, leading to boiler light up
Develop Skills for:
• Initiating the Steps for Boiler Cold Start up
• System & Auxiliaries’ Line up for Start up
• Conducting sequential operations up to Purge Ready

Contents
• Boiler Light-up Sequence – Brief Overview
• Electrical System Charging – General Note
• Establishing Mechanical Systems - General Note
• Boiler Light-up Activities – Descriptive View

SAFETY CHECK LIST FOR BOILER LIGHT UP
Check Points/ Responsibility
1. Fire Hydrant system is available at all floor
2. Fire extinguisher is available in all strategic locations.
3. Fire extinguisher are all tested
4. Fire hoses are placed in all fire hose box
5. No inflammable materials in and around of boiler area
6. No oil seepage near oil burner
7. Hot surfaces are properly insulated
8. All electrical points are sealed
9. All Earthing points proper
10. Overall housekeeping is good

• 11 All temporary supports are removed
• 12 Stacked materials are properly identified
• 13 Platform grating are proper
• 14 No overhang objects on the walkway
• 15 No water or oil spillage on floor area
• 16 No naked flame in and around of boiler
• 17 No loose cable and naked cable lying around
• 18 Boiler protections are checked
• 19 Safety valves are tested
• 20 All welding joints are tested and certified
• 21 Fire hydrant pump is available on auto
• 22 Jockey pump is in service and header pressure is Healthy
• 23 All fire hydrant points are leak proof
• 24 All fire hydrant points operating valves are free to operate
• 25 Trained fire safety personal are made available
• 26 Emergency handling in fire situation is displayed

• 27 Fire brigade number / safety officer number, control room number displayed at different strategic
location.
• 28 Boiler platforms are free of obstacles.
• 29 All PTWs are closed and clearance taken from service department in written.
• 30 Public announcement for awareness of boiler on fire
• 31 Boiler cold start up procedure in place.
• 32 Boiler startup vent / Blow down valve operation tested
• 33 Flue gas path free flow ensured.
• 34 APH Soot blowing is ready to take in service after lit up.
• 35 DCEOP DC Scanner and APH air motor trail taken.
• 36 Oil Level in BFP CEP ID FD PA APH CW pump, is OK.
• 37 Boiler trip on Emergency push button tested okay
• 38 Oil firing floor is manned

BOILER PRE LIGHT UP CHECK-LIST (FOR COLD START-UP)
Hindalco Industries Limited, Aditya

CW Pump
#1 motor
availability
S.no Check points Status Y/N
1 Clearance from all concerned departments
2 All interlok and protection check
3 Fire Hydrant system in Auto and header to Unit charged (Hose-pipe readiness)
4 Boiler Illumination adequate
5 All Boiler Man-hole and Pent-house doors and hoppers have been closed
6 Proper insulation and cladding present
7 Safet valve gagging removed
8
Critical valves MOVs operation checked like EBD,CBD,IBD, Startup vent,MS123,E02,E03,
9 Stairs and walkways free from obstacle
10
Air and flue gas path including ESP normalised, shaft heater and support heaters and hopper hearter are charged 08 hr before the
lightup.
11 Drum gauge glass and hydrastep normalised
12 TSP-Dozing valve normalised
13 All Drum, Eco, SH and Start-up vents open and SH drains open
14 All IBD, CBD and EBD and IBD Tank Main isolation valve closed
15 Bottom ring header drains, Eco-Drain to be open

CW Pump
#1 motor
availability
16
Drain before MSV open
17
Eco-Recirculation valve open
18
SH and RH Spray valves closed
19
Furnace inspection window cooling water charged
20
All impulse line normalised
21
DMCCW valve to boiler normalised
22
Instrument and service air valve normalised
23
Sampling lines normalised and coolers charged. SWAS system in service
24
All Sootblower in retracted condition
25
Bottom ash Hopper gates closed
26
Furnace Probe retracted
27
All ignitors retracted
28
Burner tilt at 0 Deg. (Burner tilt operation checked)
29
ESP Hopper heaters charged
30
Boiler Expansion reading pointer and graph in place

CW Pump
#1 motor
availability
31 ID Fan A&B oil level (>50%)
32 FD Fan A&B oil tank level (>50%)
33 PA Fan A&B oil tank level (>50%)
34 Seal Air Fan A&B oil tank level (>50%)
35 APH-A motor gear-box, guide and support bearing oil level (>50%)
36 APH-B motor gear-box, guide and support bearing oil level (>50%)
37 Scanner Air Fan Readiness
38 LDO and HFO manual valves (supply and recirculation) open.
39 Flowmeter charged and Totalizer reading:
40 HFO temp. adequate
41 LDO and HFO tank level:
42 DMST level. Tank-1/2/3
43 Fore-bay level
44 Clarifier Level (1/2/3/4/5)
45 Raw water pond level:
46 Bunker Level. Mill-A/B/C/D/E
47 Service air Moisture Trap open for Moisture removal
48 Fire watch deployed in firing floor

Boiler Light-up Sequence
Electrical System Line-up and charging
• DG Set Trial and synchronization with station supply
• Auxiliary Steam Supply Charging (conditional)
• Establish Circulation of Cooling Water System
• Establish ACW System
• Establish DM Transfer and CST make-up system
• Establish DMCW System
• Establish Compressed Air System.
• Establish LDO system
• Establish main condensate system into operation
• Normalize LP Dosing System
• Establish Feed water system into operation
• Initial Boiler Filling line-up
• Service air line Draining Moisture removal

Boiler Light-up Sequence
• Boiler Drum Filling with BFP
• Establish BCW Pumps into operation
• Starting and warm-up of fuel oil system
• Line-up of Flue Gas path
• Establish APHs into operation
• Put ID Fans into operation
• Put FD Fans into operation
• Furnace Purging
• Rechecking Boiler line-up for light-up
• Boiler Light-up with LDO
• Boiler Pressure raising

Physical Checks:
Physical Checks:
1. Make a general inspection of the boiler as a whole and carry out all general pre
light up checks.
2. Ensure that a proper drum level is maintained in the boiler drum.
3. Ensure readiness of ERV (Manually pilot valve checking)
4. Check the air and flue gas path.
5. Ensure that the light oil header pressure and the atomizing air pressure normal.
6. Elevation AB & Elevation CD oil guns are in Remote condition and oil & air- line are
normal.
7. Ensure all fan outlet gate/dampers closed.
8. Fuel additive air-line to be charged slightly for cooling purpose.(For RPD)

• 10. Ensure that De-super heater Spray line is isolated.
• 11. Ensure that APH and its LOP are running in regenerative APH.
• 12. Ensure that Scanner air fan AC is running.
• 13. Ensure that PA/FD Fan lube oil & Mill lube oil systems are in
service and adequate pressure is maintained.
• 14. Ensure that ESP rappers are running and ESP hopper heater
switched ON.
• 15. Ensure that Burner tilt in horizontal position.
Physical Checks:

Furnace Purging Furnace purging is done before boiler light-up to ensure that any incombustibles in the Furnace and APH are removed from
the circuit to avoid furnace explosion due to unwarranted and uncontrolled burning of these left out combustibles when fuel supply is given for
light-up.
7.2.1 Purge permissive:
• No boiler trip
• APH rotating
• All LONV closed
• LOTV closed
• All Scanners “NO flame”
• All pulverizer “OFF”
• All feeders “OFF”
• Both PA “OFF”
• All HAG closed and CAD < 5% open
• All auxiliary air damper modulating
• Air flow >30% and <40%
Furnace Purging Operation As these permissives are satisfied, purge ready lamp goes on. Push the Push to Purge button to start purging cycle

of 5 minutes. Ensure that none of the permissives are lost during the purging else the cycle will be disrupted. As the purging cycle is
completed, Boiler MFT can be made to reset. The Boiler is ready to be lighted-up. The HOTV and LOTV may be opened to proceed for Boiler
light-up.
Furnace Purging :

7.2.2 Checks During Boiler Lit Up:
• 7.2.2 Checks During Boiler Lit Up:
• Check for any oil leakages/ seepages.
• Check oil gun flame condition and no any oil spillage in the furnace.
• Check drum metal differential temperatures should not exceed 50 o
C.
• Maintain drum level (Very high and very low level should be avoided).
• Final SH drain should be open right from the very beginning.
• Open CBD to maintain continuous flow from economizer.
• Check that phosphate dozing in boiler drum is done or not.

8. Start up Sequence / Operating procedure
1. Inform chemical lab about boiler lit-up.
2. Call fire man before lit-up on boiler site.
3. Start ID and FD fan as per their respective SOP’s and establish air flow >30% and <40% of total air flow and
maintain furnace draught of -5 to -10 mmwc.
4. Start furnace purge by pressing start purge push button on BMS panel.
5. Check that ‘’PURGE COMPLETE’’ light appears after 5 minutes.
6. Open LOTV maintaining oil pressure apx. >7 kg/cm2 as per the flame stability
7. Taking Oil Guns in service _Lit up the boiler with 1 set of oil gun (AB or CD elevation) and check the
flame healthiness. Press pair 1-3 or AB 2-4 start button for LDO and observe the following sequence:
AB-1 oil gun advances
I. The spark rod advances.
II. The ignitor is ignited for 15 secs.
III. The atomizing steam/ air valve opens.
IV. LONV valve opens.
V. Discriminating scanner senses flame.
VI. HEA ignitor is retracted after 15 secs.
VII. AB-3 oil gun advances after a time delay of 30 secs.

8. Oil flame to be watched carefully for proper combustion.
9. Keep the start-up vent valves open.
10. Open CBD to maintain continuous flow from economizer and start HP & LP dozing to maintain feed water, drum water quality (as per manufacturer
recommendations and chemical lab instructions).
11. Raise pressure and temperature as per the start-up curve.
12. APH soot blowing to be done at two Hrs. intervals till oil gun in service in regenerative APH.
13. Restrict the difference of drum metal temperature between top and bottom within 50 oC in order to avoid thermal stress.
14. Raise the boiler parameters in consideration with the limitation of furnace exit temperature, drum/super-heater metal temperature.
15. Start PA Fan from control desk as per PA FAN SOP.
16. Ensure PA header pressure adequate.
17. Check seal air fan header pressure is normal
18. Start coal mill from mill console or DCS as per COAL MILL SOP.
19. Open the hot air damper and increase the mill I/L pressure to 200-250mmwc to warm up the mill.
20. After achieving mill O/L temperature >70oC, start the coal feeder.
21. Start mill loading gradually by increasing the feeder speed.
22. Steam parameters are to be achieved as per turbine requirement.
23. When the rolling parameters are achieved, the turbine is to be rolled and unit synchronized.
24. The pulverizers are to be taken into service one by one according to load demand.

Boiler Pressure Raising
• With the corner gun taking in service the corresponding corner SADC
shall also be opened.
• The rate of rise of Boiler metal temperature should be maintained as per
OEM guidelines. For, very cold start-up it is advisable to maintain rate of
rise of drum metal temperature at 1.5-2 Deg C / minute and rate of rise
of steam temperature at 5.0 Deg C/ minute.( see the Startup curve)
• As the guns are taken furnace pressure may become slightly positive.
Adjust the ID fan VFD to maintain –8 to-10 mmwc furnace pressure.
Alternatively, the Furnace pressure control can be kept on auto.

• Boiler Pressure Raising
• As the guns are taken into service, Oil header pressure drops, maintain the header pressure at
recommended value. In case of HFO, the temperature also may drop, maintain the temperature
by adjusting the heater input steam flow.
• At drum pressure of 2 KSC the drum vents are to be closed.
• The CBD opening and HP dosing should be done as per chemistry recommendation.
• The manual SH drains and vents also shall be closed at drum pressure of 5 KSc .
• The start-up vent shall remain full open.
• Ensure that the Furnace temperature does not exceed 540 Deg C, in view of no steam flow in
Reheater section, as HP/ LP bypass is not charged.
• The elevation fire is proven once 3 / 4 scanners are proven. The flame failure protection is armed.
In the event of 1 or no scanners sensing flame, the elevation will vote for Boiler Flame Failure
Protection

• Open MS-2 & MS-3 Valves for MS line heating .
• Open MS-1 after heating
• Close drain before MS-1
• Re-set LPBP ( to put LPBP in service refer TG check list)
• Open HPBP warm valve
• Take HP/LP BP in service
• Start One PA Fan establish PA header pressure ~710mmWC
• Ensure at least one seal air fan is in service
• Ensure Coal available in bunkers
• Ensure all permissives of mill is available and start mill
• Open hot air gate & raise the mill temperature > 70degree

Boiler Start-up
• Establish mill air flow 43 ton/hr and open feeder discharge gate
• Ensure Furnace total air flow between 192 to 240 ton/Hr for first
feeder to put in service.
• Establish coal flow
• Close Recirculation valve of ECO- bottom Ring Header
• Regulate HPBP to control MS pressure
• Take other mills in service as required
• After establishing steam flow the drum level control transfer to 3-
element control

• After Unit synchronization take 2nd
mill, & raise load ~70MW.
• Take 3rd
mill & cut out Oil support & Charge ESP & raise load
• Start 2nd
PA Fan & do PA Fan paralleling Keep load as required.
Boiler Start-up

Dos & Don’ts
DO’s DON’Ts
 Ensure all permissive.
 Monitor pressure and temperature rise as per start up curve.
 Check oil level in all bearings of fans and pulveriser.
 Check for the flame healthiness through peep hole when oil gun firing is
done.
 Check for oil leakages during oil firing.
 Monitor the Drum water/ Steam silica.
 CBD valve 100% close.
 Bypass any protection.

Boiler Interlock & Protection
Part 2

FSSS
The FSSS is designed to ensure the execution of a safe, orderly operating sequence
in the start-up and shutdown of fuel firing equipment and to prevent errors of
omission and commission in following such a safe operating procedure.
Purpose
• Furnace purge supervision.
• Secondary air damper modulation, on/off control, and supervision.
• Light oil on-off control and supervision.
• Heavy oil on-off control and supervision.
• Pulveriser and feeder on-off control and supervision.
• Flame scanner intelligence and checking.
• Overall boiler flame failure protection.
• Boiler trip protection

BOILER INTERLOCK FOR START-UP
Before any fuel firing can take place, (initially or after a boiler trip) a successful
furnace
purge cycle must be completed. To start a furnace purge cycle proceed as follows:
• The light oil trip valve is proven closed.
• All the light oil nozzle valves are proven closed.
• The heavy oil trip valve is proven closed.
• All the heavy oil nozzle valves are fully closed.
• All PA Fans are off.
• All feeders are off.
• All hot air gates are fully closed.
• All the flame scanners show No Flame
• No boiler trip command is present.
• Air flow > 30% and < 40 %
• All auxiliary dampers are modulating.

ID FAN INTERLOCKS
Conditions existing when the unit is shut down and prior to starting
off
ID fans.
a) ID fan 'A' & ID Fan 'B' off
b) Regulating inlet dampers of fans A & B fully open
c) Inlet gates of fans A & B open
d) Outlet gates of fans A & B open
e) The regulating inlet dampers & VFD control will be on manual
control during shutdown.

ID FAN INTERLOCKS
Starting ID Fan 'A' (ID fan 'B' is off)
ID fan 'A' shall be prohibited from starting till
the following conditions are satisfied:
i. Flue gas path available.
ii. Regulating inlet dampers of Fan-A in
minimum position.
iii. Outlet gate of Fan-A closed.
iv. Inlet gate of Fan-A closed
v. Fan/Fan motor bearing temperature not
very high.
vi. Motor winding temperature is not very
high
vii. One of the air heaters is running with its
inlet and outlet dampers kept open.
viii. VFD system healthy.
Tripping of ID Fan A (ID Fan B is off)
ID fan 'A' shall trip automatically under
following conditions.
i. ID fan A bearing temperature very high
(prior to this, ID fan A bearing temperature
high shall be annunciated in DCS) contacts
shall be generated from RTD.
ii. ID fan A motor bearing/winding
temperature very high (prior to this, ID fan 'A’
motor bearing/winding temperature high
shall be annunciated in DCS)
iii. Post purge fan trip from FSSS
iv. Vibration level of fan/motor very high
(high to be alarmed). For fan, trip shall be
initiated with a delay of 10 minutes during
starting and running of fan.
v. VFD Fault

FD FAN INTERLOCKS
FD FAN INTERLOCKS
Conditions prior to starting FD
fans:
a) FD Fan A and FD Fan B off
b) Fan blade pitch control tilted to
maximum opening
c) Outlet dampers are fully open
d) Fan blade pitch control
regulator disconnected
e) Lube oil pumps of FD fans off
Starting FD fan A (FD fan B is off):
a) FD Fan A shall be prohibited from starting until the
following conditions are satisfied:
i. ID Fan A or ID Fan B is on
ii. Fan A blade pitch in the minimum position
iii. Outlet damper of fan A in closed position
iv. Fan/motor bearing temperature not very high
v. Motor winding temperature not very high
vi. Lube oil system permissives satisfied.
Tripping of FD fan A (FD fan B is off)
FD fan A shall trip automatically under the following
conditions:
FD fan A bearing temperature too high
FD fan A motor bearing/winding temperature too high.
Both ID fans trip
Post purge fan trip
Vibration level of fan or motor very high (high to be
alarmed). For fan, trip shall be initiated with a delay of 10
minutes during starting and running of fan

PA FAN INTERLOCKS
Conditions prior to start up
a) PA fan A and PA fan B off
b) Outlet gates of fan A and fan B closed
c) Blade pitch control of fan A and fan B in closed
position.
d) Blade pitch control regulator disconnected
e) Lube oil pumps of PA Fan off
Starting PA fan A (PA fan B off)
PA fan A shall be prohibited from starting until the
following conditions are
satisfied:
i. Blade pitch of PA Fan A in the minimum position
ii. Outlet gate of PA fan A in closed position
iii. Anyone FD fan is on
iv. Purge complete
v. PA fan and fan motor bearing temperature not
very high
vi. Motor winding temperature is not very high
vii. Lube oil system permissive satisfied.
Tripping of PA fan A (PA fan B is off)
PA fan A shall trip (PA fan B is off) under
the following conditions:
i. PA fan A bearing temperature too high
(prior to this bearing temperature high
shall be annunciated in DCS)
ii. PA fan A motor bearing/winding
temperature too high (prior to this, motor
bearing/winding temperature high shall
be annunciated in DCS)
iii. Boiler trips
iv. Vibration level of fan or motor very
high(high to be alarmed). For fan, trip
shall be initiated with a delay of 10
minutes during starting and running of
fan.

BOILER PROTECTIONS
MASTER FUEL TRIP (MFT)
A MASTER FUEL TRIP command stops all fuel inputs by tripping all the Pulverisers, all the
feeders and all oil guns, closing the Heavy oil trip valve and closing the light oil trip valve.
Master Fuel Trip is initiated by any one of the following conditions :
• Less than fire ball and loss of AC at any elevation in service (See the NOTE 5).
‐
• Drum water level very low for more than 5 seconds.
• Drum water level very high for more than 10 seconds.
• Both FD Fans off.
• Both ID Fans off.
• Air flow is less than 30%
• Furnace pressure very low.
• Furnace pressure very high.
• Loss of all fuel trip.
• Unit flame failure trip.
• Both emergency trip Push Buttons pressed (Operator initiated boiler trip)
• Loss of 24V DC.
• Loss of Reheater protection.
• Loss of 220V DC for more than 2 second.

LESS THAN F.B. AND LOSS OF AC IN ANY ELEVATION
Less than fire ball and loss of AC in any elevation in service:- when all the mills are not in service
and there is a loss of power supply (240 V AC for Solenoids) at any of the elevation in service.
‐
Under this condition as ignition energy will not be proper (no fire ball), the HO elevation (Oil)
cannot be allowed to run without control (as there is no power supply). Hence the boiler must be
tripped to shut down the elevation.
2 SEC
AB Started
CD Started
DE Started
2/3 Block
All Coal Feeder off
2 SEC
AB Started
CD Started
DE Started
2/3 Block
All Coal Feeder off
2 SEC
AB Started
CD Started
DE Started
2/3 Block
All Coal Feeder off
2/3 Block
MFT-1
MFT-2
MFT-3
F.B & Loss Of AC

DRUM LEVEL PROTECTION
If the drum level falls below the setpoint, there is risk of the boiler running
dry. If the level is higher than setpoint, there is risk that wet steam could carry
over to the turbine, causing damage to the turbine blades.
So, in order to avoid damage to the steam drum, boiler and turbine, Two types
of protection are provided in FSSS.
Boiler trip on drum level very low
Boiler trip on drum level very high

Drum Level V Low .
2/3
Block
2/3
Block
Drum
level
V. Low
GT
-250
mmWc
Drum L-
1
Drum L-
2
Drum L-
3
2/3
Block
2/3
Block
MFT-1
MFT-
3
MFT-2
5 SEC
5 SEC
5 SEC
Drum L-
1
Drum L-
2
Drum L-
3
Drum L-
1
Drum L-
2
Drum L-
3
GT
-250
mmWc
GT
-250
mmWc
GT
-250
mmWc
GT
-250
mmWc
GT
-250
mmWc
GT
-250
mmWc
GT
-250
mmWc
GT
-250
mmWc

Drum Level V High .
2/3 Block
2/3 Block
Drum level
V. High
GT
275mmWc
GT
275mmWc
Drum L-1
Drum L-2
Drum L-3
GT
275mmWc
2/3 Block
GT
275mmWc
GT
275mmWc
GT
275mmWc
2/3 Block
GT
275mmWc
GT
275mmWc
GT
275mmWc
MFT-1
MFT-3
MFT-2
10 SEC
10 SEC
10 SEC
Drum L-1
Drum L-2
Drum L-3
Drum L-1
Drum L-2
Drum L-3

BOTH ID FAN TRIPPED
An induced draught fan (ID fan) is provided to maintain a negative pressure
in the furnace by sucking the products of combustion from it with a slight
positive pressure at the discharge end vis-à-vis the bottom of the
chimney/stack.
This positive pressure, assisted by the stack effect of the heated chimney
( 120°C), causes the flue gas to leave the chimney and mixes it with the
∼
surrounding atmosphere.
If both the ID fan tripped, then flue gas will not be sucked from furnace which
will cause furnace to pressurize. To avoid over pressurization in furnace Boiler
to be tripped in MFT to avoid any damage to the furnace.

Both ID Trip.
ID Fan A OFF
from 6.6 kV
ID Fan B OFF
from 6.6 kV
2/3
Block
2/3
Block
ID Fan A OFF
from 6.6 kV
ID Fan B OFF
from 6.6 kV
2/3
Block
2/3
Block
ID Fan A OFF
from 6.6 kV
ID Fan B OFF
from 6.6 kV
2/3
Block
2/3
Block
2/3 Block
MFT-1
MFT-2
MFT-3
BOTH ID
TRIPPED

BOTH FD FAN TRIPPED
Boilers have forced draft (FD) fans to supply air for
the combustion of fuel. In the case of both FD fans
tripping, the boiler will go for trip as the air supply
to the fuel is cut off in full or excluding the primary
air depending upon the system design. The PA fan
also trips as soon as all the FD fans trip.

Both FD Trip.
FD Fan A OFF
from 6.6 kV
FD Fan B OFF
from 6.6 kV
2/3
Block
2/3
Block
FD Fan A OFF
from 6.6 kV
FD Fan B OFF
from 6.6 kV
2/3
Block
2/3
Block
FD Fan A OFF
from 6.6 kV
FD Fan B OFF
from 6.6 kV
2/3
Block
2/3
Block
2/3 Block
MFT-1
MFT-2
MFT-3
BOTH FD
TRIPPED

Low Air Flow < 30%.
2/3
Block
2/3 Block
Low Air Flow
<30%.
Low Air Flow < 30% , 192 TPH
2/3
Block
2/3
Block
MFT-1
MFT-3
MFT-2

Furnace Pressure V High .
2/3
Block
2/3 Block
Furnace
Pr. V.
High
GT
140mmWc
GT
140mmWc
Fur Pr-1
Fur Pr-2
Fur Pr-3
GT
140mmWc
2/3
Block
GT
140mmWc
GT
140mmWc
Fur Pr-1
Fur Pr-2
Fur Pr-3
GT
140mmWc
2/3
Block
GT
140mmWc
Fur Pr-1
Fur Pr-2
Fur Pr-3
GT
140mmWc
GT
140mmWc
MFT-1
MFT-3
MFT-2

Furnace Pressure V Low .
2/3
Block
2/3 Block
Furnace
Pr. V. Low
LT -
165mmWc
Fur Pr-1
Fur Pr-2
Fur Pr-3
2/3
Block
Fur Pr-1
Fur Pr-2
Fur Pr-3
2/3
Block
Fur Pr-1
Fur Pr-2
Fur Pr-3
MFT-1
MFT-3
LT -
165mmWc
LT -
165mmWc
LT -
165mmWc
LT -
165mmWc
LT -
165mmWc
LT -
165mmWc
LT -
165mmWc
LT -
165mmWc
MFT-2

FLAME FALIURE TRIP
Unit Flame Failure Trip” occurs if all the ten elevations vote for No flame along
with the arming signal. Unit Flame failure Trip” circuit is armed 2 seconds after
any coal elevation is put into service.
Elevation AB No Flame Vote
Elevation BC No Flame Vote
Elevation CD No Flame Vote
Elevation DE No Flame Vote
Any Feeder Proven 2 Sec
Flame
Failure
Trip

Flame Failure Vote Logics.
Feeder A Off
2 Sec
Feeder B Off
Elevation AB Any HFO
Nozzle Valve Not Closed
Elevation AB 2/4
Nozzle Valve Not Proven
Elevation AB
Scanners No Flame
Feeder C Off
2 Sec
2 Sec
Elevation BC Scanners No Flame
Elevation AB
No Flame Vote
Elevation BC
No Flame Vote
Elevation DE
No Flame Vote
Feeder D Off
Feeder E Off
Elevation DE Scanners No Flame

LOSS OF ALL FUEL
Loss of All Fuel Trip” circuit is armed as
soon as oil firing is introduced into the
furnace,
through any one of the following conditions.
i.e., if any oil burner comes into service. This
condition also indicates that the “Boiler is
on”.
This condition is generated when any one of
the following conditions occurs :
Elevation AB any LO nozzle valve NOT
closed
Elevation AB any HO nozzle valve NOT
closed
Elevation CD any HO nozzle valve NOT
closed
Elevation DE any HO nozzle valve NOT
closed
“Loss of All Fuel Trip” condition is generated if all the
following conditions exist along
with “Loss of all fuel trip arming” condition.
All feeders are off
.AND.
Elevation AB back up trip or All HO valves are closed
.AND.
Elevation CD back up trip or All HO valves are closed
.AND.
Elevation DE back up trip or All HO valves are closed
.OR.
HO Trip Valve not open.
.AND.
Elevation AB Backup trip or All LO valves are closed
.OR.
LO trip valve is not open
Loss of all fuel trip arming memory is reset 5 seconds
after MFT trip occur

Loss of all fuel arming
SET
RESET
MFT 5 SEC
Any elevation
¾ Nozzle valve proven
All feeders off 2 SEC
All HFO Nozzle
valve closed
All feeders off
HOTV NOT OPEN
2 SEC
All HFO Elevation Trip
Loss of all
fuel trip
Loss Of Fuel Trip.

REHEATER PROTECTION
Reheater protection shall be provided as part of Boiler House Auxiliaries
Interlock
and protection system. This protection is provided to protect the Reheater
against
starvation of steam flow during abnormal conditions. To take care of Reheater
protection, the Boiler shall be tripped after 10 seconds, when any of the
following
conditions occur:
a) When Boiler is working and if
i) Generator circuit breakers open and
ii) HP Bypass or LP Bypass valves remain closed less than 2%
b) When Boiler is working and if
i) Turbine trips and
ii) HP Bypass or LP Bypass valves remain closed less than 2%

Loss of 220V DC.
2/3
Block
2/3 Block
Loss of
220 V DC
Fail
220 V DC Fail
2/3
Block
2/3
Block
MFT-1
MFT-3
MFT-2
2 SEC
2 SEC
5 SEC
220 V DC Fail
220 V DC Fail

Loss of 24V DC.
2/3
Block
2/3 Block
Loss of
24 V DC
Fail
24 V DC Fail
2/3
Block
2/3
Block
MFT-1
MFT-3
MFT-2
1 Min
1 Min
1 Min
24 V DC Fail
24 V DC Fail

MFT Logic Description
• “Less than fire ball and loss of AC in any elevation in service” condition occurs,
when all the mills are not in service and there is a loss of power supply (240 V AC for
‐
Solenoids) at any of the elevation in service.
• “Loss of Reheater protection”.

MFT: MASTER FUEL TRIP
1. Both ID Fans off.
2. Both FD Fans off.
3. Furnace pressure very low. (-165mmwc)
4. Furnace pressure very high. (+140mmwc)
5. Drum level very low (TD 5 sec) (-250mm)
6. Drum level very high (TD 10 sec). (275mm)
7. Air flow is less than 30% (192 TPH)
8. Loss of Reheater protection. (TD 10 sec)
9. Loss of 24V DC after MFT reset OR Purge pressed (1min Pulse for all MFT channel)
10.Loss of 220V DC (TD 2 sec)
11. Less than fire ball and loss of 240V AC at any elevation in service. (TD 10 sec)
12.Loss of all fuel trip
13.Unit flame failure trip
14.Emergency trip Push Buttons pressed
15.Spare feeder

“Loss of All Fuel Trip”
•Arming: Any LONV/ HONV not closed ie, oil firing is introduced into the furnace i.e. if
any oil burner comes into service, This condition also indicates “Boiler is on”
o Elevation AB any LO nozzle valve .NOT. closed
o Elevation AB any HO nozzle valve .NOT. closed
o Elevation CD any HO nozzle valve .NOT. closed
o Elevation DE any HO nozzle valve .NOT. Closed
Loss of All Fuel Trip will occur when
Boiler is ON
AND
ALL FEEDERS ARE OFF.
AND
LOTV/HOTV IS NOT OPEN. OR ALL ELEVATION LONV /HONV CLOSED.

•“Unit Flame failure Trip” circuit is armed 2 seconds after any feeder put in service
(ON feedback) for 50secs.
ELEVATION A
‐
Feeder A is not proven.
‐
.OR.
Elevation AB 3 out of 4 Fireball scanners show no flame .AND. Elevation AB 2 out of 4
‐ ‐
nozzle valves not open.
.OR.
Elevation AB started and loss of power.
‐
ELEVATION B
‐
Feeder B is not proven
‐
.OR.
Elevation AB 3 out of 4 Fireball scanners show no flame .AND. Elevation AB 2 out of 4
‐ ‐
nozzle valves not open .
.OR.
Elevation AB started and loss of AC (TD-2sec).
‐
.AND.
Elevation BC 3 out of 4 fire ball scanners show no Flame
‐

Boiler Operation

• Boiler Overview
• Boiler Water & Steam circuit
• Boiler Cold startup
• Boiler Shutdown
• Boiler Natural Cooling
• MFT
• Boiler Preservation
• Boiler Hydrostatic Test
• APH Water Washing
• Few Rare but important Emergencies
Session Synopsis

Boiler Overview Aditya CPP 6*150MW
Boiler Detail:
• Design Pressure at Drum; 164 Kg/cm2;
BMCR ( Boiler Maximum Continuous Rating):
• Drum : 154 Kg/Cm2, 343 deg C
• SH O/L: 139 Kg/cm2; 540 deg C, 510 TPH
• RH O/L: 34.58 Kg/Cm2, 540 deg C, 407.1 TPH
• RH I/L : 36.57 Kg/Cm2, 353.4 deg C
• ECO I/L : 157.3 Kg/ Cm2, 242 deg C
Safety Valve setting in Kg/Cm2:
• Drum: 164 Kg/Cm2:, 169 Kg/Cm2:
• SH outlet: 147.6 Kg/Cm2:, ERV 145.8 Kg/Cm2:
• CRH: 42.5 Kg/Cm2:
• HRH: 39.5 Kg/Cm2: & 41.6 Kg/Cm2:
• Soot blower: 40 Kg/Cm2:
Environmental Norms: SPM < 50 mg/NM3, NOX< 450 PPM, SOX< 600 PPM, Hg<0.03 mg/Nm3
Boiler Heating surface area: 13136 sq. M

• Ensure all PTWs are returned &it is expected that all the associated equipment are
available . PSSR to be dully checked (if Boiler S/D > 7days)
• Charge Instrument air & service air.
• All wall soot blowers & LRSB's are in retracted condition.
• Both Furnace temperature probes available.
• Availability of Flue Gas Path
• All manholes are closed
• Flue gas side APH inlet & outlet dampers are opened
• ESP Inlet gate & outlet gate opened.
• ID Fan inlet & outlet gate closed.
• ID Fan IGV in closed position.
• Keep ESP hopper heaters & space heaters in ON condition.
• Availability of Air Path
• Primary Air side APH inlet& outlet dampers opened
• Secondary Air side APH bypass damper is in opened condition
• Secondary Air side APH inlet& outlet dampers opened
• Individual PA Fan discharge gate closed & blade pitch in closed condition.
• Individual SA Fan discharge damper closed& blade pitch in closed condition.
• ESP Inlet gate & outlet gates open.
Boiler Pre Start-up Checks

• Close boiler water side master drain valve.
• If D/A charging time not sufficient, then line up boiler initial filling from bottom ring header
drain & economizer drain through boiler fill pump. Open Economizer recirculation valve (E-
17). Boiler filling completed when drum level shows 0mmWC.
• Charge boiler side all DMCW system in service.
– ID FAN bearing oil cooler.
– ID Fan oil cooler.
– Boiler manhole cooling.
– APH Guide bearing oil cooler.
– APH support bearing oil cooler.
– APH oil carry over probe.
– PA Fan cooler.
– FD Fan cooler.
– Mill & cooler.
– Cooling water to sample coolers (may be charged later on before charging sampling
isolation valve)
• Start both Air preheaters.
• Normalize Instrument air to SADC.

• Charge LDO system at boiler.
• LOTV is closed.
• All Drain valves of LDO after LDO shutoff valve to LONV should be closed.
• LDO pump is in service with short recirculation maintaining header pressure 24
Kg/Cm2
• Slowly open Boiler LDO shut off valve.
• LDO Flow meter inlet & outlet valve opened & bypass valve closed.
• Manual isolation before & after LOTV opened.
• LOFCV bypass manual isolation valve closed.
• Manual isolation after LOFCV opened.
• ALL corner manual isolation of LONV is opened.
• ALL LONV is in closed condition.
• LDO to CD elevation is in opened condition.
• Service air moisture is removed by opening the drain valve & ensure service air
header pressure is 4 KG/Cm2 to 7 KG/Cm2.
• All corners air valves manual isolation valves are in opened condition.

• Thermal deaeration relies on the principle that the solubility of a gas in water
decreases as the water temperature increases and approaches its boiling point
• It remove dissolved gases from boiler feedwater. Deaeration protects the steam
system from the effects of corrosive gases. It accomplishes this by reducing the
concentration of dissolved oxygen and carbon dioxide
 Charge LTPRDS from other unit.
 From LTPRDS D/A initial line heating is provided. Slowly open AS-43, check
condensate is removed from drains.
 Open D/A initial heating valve AS-7 slowly to start initial heating.
 D/A temperature to be maintained ~100deg C
(DEAERATOR INITIAL HEATING)

• Open drum vents
• Open SH vents.
• Open SH drains. (Note: filling to SH line valve is closed)
• Open RH vents.
• MS-1, MS-2, MS-3 closed.
• SH spray control station is isolated.
• RH spray control station is isolated.
• Start up vent opened.
• Burner tilt is at 50%.
• Do boiler filling through BFP .
• Boiler Hot rinsing to be done by opening boiler drains & again boiler filling to be done
through BFP.

• Start one ID Fan.
• Start one FD Fans.
• Start second ID Fan & FD Fan.
• Maintain total air flow around 210THP ie more than 30% & less than 40% (191 TPH
to 255 TPH) by FD Fan blade pitch control.
• Start AC Scanner Air Fan (Also ensure the power normalization of DC Scanner Air
Fan)
• Open igniter cooling air valve.
• Check the boiler PURGE permissive are satisfied.
• Start boiler purging. During purging ensure all SADC are opened 100%.
• After completion of purging push reset SADC.
Boiler Start-up

PURGE PERMISSIVE
• No Boiler Trip
• HOTV Closed
• LOTV Closed
• All HONV Closed
• All LONV Closed
• All PA fans Off
• All Feeders Off
• All Hot Air Gates Closed
• All Auxiliary Air Dampers
Modulating
• Air Flow > 30 % &< 40%
• All Scnaner no flame
POST PURGE FAN TRIP
• After 5 minute counting period
expires, the “Post Purge Fan Trip”
memory is set,
• If very high or very low furnace
pressure exists, the post purge fan
trip command is issued (for
tripping FD & ID fans).
• When any HO / LO valve is open,
this is reset.

LOTV (Light Oil Trip Valve) Operation
• Once the boiler trip circuit is reset and all the LONVs are proven closed.
• Press the LOTV "open" push button, will open LOTV provided the light oil header pressure is
adequate.
• Pressing the LOTV "Close" push button will close the valve. The LOTV also closes
automatically under following conditions:
MFT
.OR.
Any LONV not closed
.AND.
Light oil header pressure very low (From 2/3 logic) (<5 KSC)
.OR.
Atomizing air pressure very low (From 2/3 logic) (<2.5 KSC)
.AND.
No light oil elevations in start or stop.
• The LOTV will be commanded to close on loss of unit Critical Power (+24V DC).

LIGHT OIL ELEVATION START
(Elevation AB – PAIR MODE)
Establish light oil elevation start permit by the following Conditions being satisfied.
• No master fuel trip.
• Light oil trip valve proven fully open
• Light oil elevation trip occurs under any of the following conditions:
• Master fuel trip.
• Light oil trip valve not open.

• Light up the boiler at AB elevation.
• Keep inspection doors of Magaldi conveyors open & monitor it for checking of any oil accumulation.
• Start APH soot blowing from Air.
• During warming up period keep open the economizer recirculating line valve.
•Blow down the unit as required maintaining the drum water level in sight in the gauge glass.
Note: The firing rate should be controlled to keep the furnace exit gas temperature below 540 deg C
until steam flow through Reheater is established. Establish a slight flow through superheater by
opening its start-up vent.
•Increase the firing rate as required within permissible limit of 110 degC /hr. to raise the pressure.
•Maintain drum water level at normal level.
•Close drum vents at 2KG/Cm2.
Boiler Start-up

• Close all SH drain & vents at 5KG/Cm2.
NOTE: SH flow to be maintained through start up vent only.
Drain before MS-1 to be kept opened till MS-1 does not opened fully.
• While the boiler is heating up, frequent checks should be made of the boiler
expansion movements.
• Give boiler hot blowdown through bottom ring header drain at drum pressure
10KG/CM2.
• Check boiler water concentrations and constituents as frequently as required to
maintain proper boiler water conditions & start TSP dosing as per chemical
department.
• Open MS-2 & MS-3 & then Open MS-1 to charge MS line.
• Charge HTPRDS , complete Vacuum pulling, Close RH Vent valve.
Boiler Start-up

• Charge HP & LP bypass & Steam dumping to be done for achieving water & steam
properties as per following dumping scheme.
•Steam from MS Line  HPBP CRH  RH  HRH  LPBP  Dumped in
Condenser  CEP  REQUIRED FLOW TO MAINTAIN HOTWELL LEVEL 0mm
WITHOUT MAKE UP THROUGH DEATERATOR LEVEL CONTROLLER  THROUGH
DOWN STREAM MANUAL VALVE OF CST EXCESS RETURN DUMP VALVE TO
ATMOSHPHERE.
•NOTE: Any time degree of superheat should not come below 50degC.
•Close startup vent.
Boiler Start-up

01/11/2025 11
• To minimize the possibility of adverse visible stack emission it is desirable to use the
warmup oil guns till attained to drum pressure ~35 Kg/cm 2 and secondary air temperature
177 deg.C before firing pulverised coal.
• Start first PA Fan.
• Either Mill A or Mill-B mill cutin to be done with three oil gun support at AB elevation.
• Further increase the boiler firing to raise MS pressure & temperature around 40 KG/CM &
350 deg. HRH pressure 3 to 5 Kg/Cm2 & HRH temperature around 350deg C Flow through
HPBP around 70TPH.
• Steam dumping process may be considered to be completed after achieving following
parameters:
Boiler Start-up
DESCRIPTION PH CONDUCTIVITY
µcm
SILICA (ppb) Total Iron
(ppb)
Hydrazine
ppb
FEED WATER 9.0 – 9.4 4 - 8 ≤ 20 ≤ 10 20 to 30
BOILER WATER 9.1-9.8 <50 < 1000
CONDENSATE
WATER
9.0 to 9.4 4 - 8 ≤ 20
SH STEAM 9.0 to 9.5 4 - 8 ≤ 20 ≤ 10

• If unit going for long shutdown, better to empty the coal bunker by keepings miils
in service. Stop coal feeding in all bunkers.
• Reduce the MS temperature & HRH temperature up to 510~520 deg C.
• Gradually reduce the load
• Do not reduce load & steam temperature at same time because of the danger to
exceed the permissible relative expansion and the lower margin of the TSE.
• Charge HTPRDS from other unit.
• Operate all soot blowers.
• HPLP bypass to be cut-in.
• Further reduce the load keep flame stability, if required Oil support to be taken.
• Desynchronize the TG.
• Stop coal feeder & mills.
• Manually do the MFT.
• FILL UPTO + 150 MM ABOVE NORMAL LEVEL IN DRUM DURING BOXING UP OF
BOILER.
• Open the economizer recirculating valve.
• Allow boiler for natural cooling.
Boiler Shutdown

• Close MS-1,MS-2, MS-3
• Ensure closing of CBD, EBD, IBD, various sampling line isolation valves, soot
blower isolation valve, SH vents & drains, RH vents.
• Stop one FD Fan & ensure closing of discharge damper of FD Fan.
• Stop one ID Fan & ensure closing of IGV, discharge & suction gate of ID Fan.
• Reduce airflow to minimum & boiler draft to be maintained at -2mmwc.
• Airheaters should not be taken out of service until the airheater gas inlet
temperature has dropped to below 200 deg C. Atleast one FDFan, one ID Fan
to be kept in service.
NOTE: running an airheater with the gas inlet temperature above 200 deg. C
and no air flow through it will result in seal damage and subsequent excessive
leakage during operation.
Boiler Natural Cooling

• When airheater gas inlet temperature has dropped to below 200 deg.C. Stop
FD Fans, ID Fans, & air heaters.
• Open super heater vents at 5Kg/Cm2 (g)
• Open drum vents when the unit pressure has decayed to 2 kg/cm2 (g).
• The cooling rate must not exceed the recommended saturated steam
temperature decrease. Monitor drum metal differential temperature it
should be less than 50 degC.
• When condenser vacuum is killed, Open RH vents & CRH line atmospheric
drain at turbine end.
• If boiler draining is required, the boiler water temperature should be reduced
to at least 90 deg C before draining.
Boiler Natural Cooling

• Fill the Boiler with DM water containing 10 ppm of ammonia and 200 ppm of
Hydrazine. This pH of the solution should be approximately 10. Add Dm water from
the outlet of non-drainable sections.
• Increase the hydrazine and ammonia concentrations in the boiler, economizers and
feed water heaters (tube side) and associate piping to 200 ppm and 10 ppm
respectively.
Boiler Preservation
Boiler Preservation
pH Hydrazine (ppm)
10 to 10.5 200 - 300

Hydro test pressure is considered by IBR regulation 268 & IBR regulation 379.
IBR regulation 268: Testing at Maker’s work,
Tested hydraulically prior to welding at a pressure less than 1.5 times the
maximum working pressure.
IBR regulation 379: Testing at site:
 1.25 times the maximum working pressure, if all components as per
Regulation 268 are tested.
 1.5 times the maximum working pressure, if any of the components as per
Regulation 268 are not tested .
IBR Regulations

"Design Pressure" means:-
(i) In relation to a natural or assisted circulation boiler, the maximum
allowable working pressure in the steam drum of the boiler;
(ii) In relation to a once through forced-circulation boiler, the
maximum allowable working pressure at the final superheater steam
outlet
Reference: https://dpiit.gov.in/sites/default/files/boiler_rules_updated/reg2.htm
IBR Regulations

 The boiler shall be hydro tested for confirmation to IBR code requirement on boiler
drum, economizer, water wall and super heater at a pressure of 1.25 times of the
design pressure ( MWAP at drum). i.e 164 X 1.25= 205 kg/cm2 (g)
 Rated Water Temp: Water temperature should be > 21 DegC and < 49Deg C
 Quantity of DM water:250m3
• Time of holding the test pressure: The Test pressure is Held for 30 Consecutive
Minutes in presence of Inspection Authority.
Boiler Hydrostatic test

DM Water Quality
SI.No Parameter Unit Value
1 PH at 25 deg C 7 +/- 0.2
2 Conductivity µS/ cm <1
3 Total Hardness Nil
4 Total Silica ppb <20
5 Chloride ppb Nil
6 Sodium ppb <3
DM Water Quantity: Approximate – 250 m³

• Ensure all PTWs related to boiler are returned.
• Sufficient DM water is available
• Hydrostatic test pump is available & its connections are proper.
• Close boiler water side master drain valve.
• Open Eco outlet header vent valve.
• Open drum vent valves.
• Close SH drains & drain before MS-1.
• Start boiler fill pump, (MIV-5&6 open, MIV- 4&7 close)
• Complete boiler initial filling from SH filling line through boiler fill pump. This is
done to prevent carryover of suspended impurities in to super heater.
• Open Economizer recirculation valve (E-17).
• Raise boiler drum pressure up to 2 KSC & close drum vents & at 5 KSC close SH
vents.
• Line up boiler filling line to take makeup of hydrostatic tank.
• At 12 KSC, stop taking water in boiler from initial boiler filling line by closing MIV-6.

01/11/2025 11
Boiler Hydrotest

• Line up the hydrostatic test pump & Start hydrostatic test pump & raise boiler
pressure through SH drain by opening MIV 4 & closing MIV 5.
• Pressure rising rate to be maintained below 10 KSC per minute till 50 KSC & hold
the pressure for checking the passing of valve.
Note: During pressure raising , no person is allowed to enter Boiler after 50 KSC.
• Stop the pressuring pump at 130 KSC & safety valves (super heater and drum)
gagging to be done .
• Further pressure rising rate to be maintained below 10 KSC per minute till 80% of
test pressure (205 X 0.8 =164 KSC).
• Beyond 80% of test pressure, pressure rising rate to be maintained less than 2 KSC
per minute till target pressure reached.
• Again pressurization pump is started and the pressure is raised to 205 Kg / cm2 .
• Once the drum pressure is raised to 205 Kg / sq.cm, the pressurization pump is
stopped and the super heater filling line valves are closed
• After witnessing pressure drop from the official pressure gauge by the statutory
authority, boiler shall be depressurized

DEPRESSURISATION:
• After completion of test, Boiler shall be depressurized at the rate 1KSC per
minute through sampling line.
• The drop rate should not be more than 1 KSC per minute for 30mins and no
appreciable deflection of components from test pressure.
• At a pressure of 60 KSC, the pressure is held and Boiler is thoroughly
inspected.
• If found satisfactory, full depressurization can be done at the rate of 1KSC
per minute
• At 2KSC the vents are left full opened.

• Ensure APH I/L FG temp between 150 ~200 Deg.
• Both ID,FD,PA fans stopped.
• All FG outlet dampers closed.
• Maintain Fire Hydrant tank level at higher side & Hydrant pump is available
• Both FD & PA duct discharge drain in opened condition.
• APH Hopper manhole duct opened.
• FG I/L & O/L Manholes opened to check performance of nozzles at HOT end & Cold
end respectively.
• Check for removal of water from ash hopper from all drain points, if water not coming
then washing should be stopped immediately
• PH value of inlet & outlet to be measured, when matches Washing to be stopped.
Samples to be taken regularly
• After washing close all water line valves. Start ID/FD fans to dry APH baskets( atleast
4hrs it should be kept in service.
APH Water Washinng

Water & Steam Quality
Water & steam quality is very important for the Power Plant Operation which includes
the following:
Sample PH Conductivity
(uS/CM)
Silica (ppb) Hydrazene
(ppb)
Phospate
(ppm)
Amonia
(ppm)
HARDNESS
(ppm)
TDS
(ppm)
TOTAL
ALKALINITY
(ppm)
Feed Water 9.0 to 9.4 4 to 8 ≤ 20 10 to 30 ≤ 1 NIL
Boiler Drum 9.1 to 9.8 <50 ≤1000
≤5 2.0 to 10.0
<0.5
NIL ≤ 50 ≤ 15
Sat. Steam 9.0 to 9.5 4 to 8 ≤ 20 <0.5
SH Steam 9.0 to 9.5 4 to 8 ≤20
BDL
<0.5
Condensate 9.0 to 9.4 4 to 8 ≤ 20 <0.5 NIL
Deaerator O/L 9.0 to 9.4 4 to 8
DM water 6.8 - 7.2 < 1 < 20 <0.5

• If the failure is such that the water level can be maintained in the gauge glass by
using the normal make-up system and the conditions require continued operation,
the boiler can be kept in service until it is more convenient to take it off the line.
• As long as the failure does not become one which involves the loss of water level in
the gauge glass, the boiler should be shut down in the normal manner, in order
that no equipment may be subjected to sudden temperature changes.
• If the failure is such that the water level cannot be maintained in the gauge glass,
then the boiler should be shut down immediately. After a shutdown because of low
water level, every effort should be made to keep the water as near normal as
possible until the boiler is cool enough to drain.
Boiler Tube Leakage

• The condenser tube leakage brings large amount of chlorides into the condensate
and consequently into the feed water. These are hardness salts and acid forming in
nature due to hydrolysis reaction at high temperatures. Whenever, the feed water
gets contaminated by the cooling water leakage from the condenser the following
things happen to the boiler water in the drum.
– pH of boiler water drops rapidly due to the acid forming nature of condenser
leakage salts.
– The phosphate level of boiler water drops down very low. This is due to the
reason that the residual phosphate is consumed by its reaction with hardness
inleakage salts to form sludge constituents.
– Conductivity of boiler water rises, due to increasing salt concentration brought
by condenser leak.
Condenser Tube Leakage

• Immediately start chemical injection pumps to maintain excess phosphate and
– pH conditions in boiler water as below:
PO4----- 5 to 20 ppm
pH----- 9.1 to 10.1
The phosphate and pH measurements in boiler water should be made every
30 minutes and the phosphate pump should be operated based on the reports.
• Increase blow down to the extent possible to keep the conductivity and chlorides in
boiler water within limits as below:
– Specific electrical conductivity----- 100 Siemens/cm (max.) at 25 deg.C
– Chlorides (as NaCl)----- 4 ppm (max.)
• Monitor the following at the interval of every 30 minutes. a. Condensate sample
either from ejector or from hot well- for chlorides and conductivity. b. Boiler water
sample- for pH, phosphate, chlorides and conductivity.
Action During Condenser Tube Leakage

• Isolate the condenser section one by one for locating the damaged section and
isolate and repair the damaged section. (If damaged condenser section cannot be
isolated and repaired, shut down the unit.
• Shutdown unit if pH of boiler water cannot be maintained above 9.6 or the
conductivity below 30 micro Siemens/cm (i.e. total dissolved solids below 15 ppm).
• Avoid unnecessary use of desuperheater spray
• If the unit is shut down for condenser repair, drain and flush the system to the
extent possible and establish wet lay-up of boiler unit and auxiliary equipment
during condenser repair.
Action During Condenser Tube Leakage

Likely Causes
•Soot blowing not done during oil gun in service
•Soot blowing not done for long time
•Accumulation of oil vapors and unburnt carbon on air preheater.
•Flue gas in let damper not closed after APH tripped.
•Flue gas temp at APH o/l increases rapidly due to reduce in cold air flow (PA/FD air
flow)
Plant Response
•APH O/L temp high alarm
•Flue gas temp at APH outlet shoots up.
•O2 across APH drop
•APH current hunting
Parameters Of Concern
•APH o/l flue gas temp
•APH current
•O2
APH FIRE

Immediate Operator Action
1. Depending upon Temperature & fire decision to be taken to trip the
boiler or to reduce the load to bring down flue gas temp within limits.
2. Stop the APH, It should be rotated by air motor during fire
extinguishing.
3. Stop ID,FD,PA. Firefighting line to be charged, manhole to be opened,
as mentioned in APH water washing. Soot blowing to be continue until
oil gun in service.
4. APH soot blowing to be carried out at every shift.
5. If Flue gas i/l damper not closed at interlock then close it from local.
6. Isolate cold air flow to the corresponding APH side by PA & FD to
control temp, once temp reduced cooling to be done by FD.
APH FIRE

Likely Causes
•Accumulation of unburnt fuel during lit up.
•Taking oil guns without purging furnace.
•Improper burning of coal
•Inadequate air or less O2.
•Starting of mill without proper ignition temperature. (light up time >300 c temp)
•Oil valve leaks-oil dropping inside ( monitor oil tank level if decreasing check oil passing
from gun MIV)
•Secondary combustion
Parameters of Concern
•Furnace draft, Air flow, Furnace temp, O2 %, Coal flow
Furnace Explosion

Precautions to avoid Furnace Explosion:
• Always purge the boiler with above 30% of full load air for about five minutes.
• Always check the flame with help of scanner or personal check.
• When boiler load is less than 30%. Keep at least 3 out of 4 oil guns adjacent, to mills
• when mill loading is less than 50%.
• Keep close watch on O2 content in gas at air pre heater inlet.
• Do not introduce fuel without sufficient ignition temperature.
• If oil tank level decreasing check oil passing from oil SOV, same gun with oil MIV to
be isolated.
• Proper SADC adjustment to be done to avoid secondary combustion.
• If Flame is lost, trip the unit and purge the furnace. NEVER try to take any LDO
gun, ensure fuel inlet valve, P. A. Fan, mill, hot air gate to mill are closed and
tripped
• Regularly check proper functioning of FSSS equipment’s.
Furnace Explosion

Fire in Bunker
Likely Causes
• High Volatile Matter coal stored in bunker and not in use long time.
• Spontaneous ignition due to stagnant coal in bunker.
• Coal coming from stocks itself having fire.
• Carry of fire from feeder to bunker.
• Failure of feeder seal air causes hot air from the mill to enter bunker
which may cause fire.
Plant Response
• Smoke coming out of bunker opening.
• Coal feeder belt may damage.

Fire in Bunker
• Inform to CHP & Stop feeding to that bunker.
• Inform fire fighting department & make necessary water spray
arrangement at feeder floor while feeding fire coal.
• Continuously monitor the bunker temp & spray the water from fire
hydrant if temp increases.
• If possible run the mill & empty that bunker at the earliest with necessary
firefighting arrangement otherwise stop the mill and close bunker o/l
gate.
• Make arrangement to remove burnt coal from the bunker manually.
• Make external fire water hose arrangement at the bunker chute if feeder
temp increases.

Fire in Coal Mill OR Mill Explosion
Likely Causes
• High % of volatile mater in coal.
• High mill outlet temp.
• Lean air mixture
• Fire coal conveyed from bunker
• Coal stored for long time at bunker
• Mill in chocked condition
• Stagnant coal in mill & mill stopped condition for long duration
Plant Response:
1. Mill outlet temperature shoots up.
2. Mill may trip on protection.
3. Surrounding may catch fire.
4. Mill gates and damper may not operate damage done by explosion.
5. Duct and bellow may damage.
6. Fluctuation in furnace pressure.
7. PA header pressure dropped rapidly.
8. Power generation decrease.

• CLOSE HAG, PLACE THE FEEDER ON MANUAL CONTROL AND CONTINUE FEEDING COAL AT A
HIGH RATE WITHOUT OVERLOADING THE MILL.
• IF FIRE IS NOT PUT BY THE ABOVE, MILL INERTING STEAM MAY BE ADMITTED INTO THE
MILL. THE MILL MUST BE KEPT RUNNING WITH THE FEEDER STOPPED FOR SEVERAL
MINUTES TILL ALL THE SIGNS OF FIRE ARE GONE.

2. IF A FIRE EXISTS COMPLETELY THROUGH THE MILL AND FUEL PIPING, CLEAR ALL PERSONNEL
FROM THE AREA SURROUNDING THE MILL AND ITS ASSOCIATED FEEDER AND FUEL PIPING.
SHUT OFF THE FEEDER AND ALLOW THE MILL TO CLEAR ITSELF ALL THE FUEL. MAINTAIN A
FLOW OF COLD AIR THROUGH THE MILL UNTIL ALL EVIDENCE OF FIRE HAS DISAPPEARED AND
THE MILL IS COLD, THEN SHUT-DOWN AND ISOLATE THE MILL.
3. WHEN FIRE EXTINGUISHED AND THE MILL HAS COOLED, STOP THE MILL. OPEN INSPECTION
DOORS CAREFULLY AND THOROUGHLY CLEAN THE INTERIOR OF THE MILL OF ANY
ACCUMULATIONS INCLUDING COAL WATER SLURRY. CHECK LUBRICANTS FOR EVIDENCE OF
CARBONIZING. CHECK ALL PARTS WHERE THE FIRE HAS OCCURRED FOR ANY DAMAGE

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