Boiler presentation

1. Study the LFO Boiler,
Problems,
Troubleshooting and
significant of different blow
down
Conducted by
AJOY DAS
SHIFT-IN CHARGE
24/06/2020
Prepared By: Ajoy Das

2. Why Auxiliary Boiler Must
Required In HFO Power Plant
Heavy fuel oil power plant operation depends upon
different integrated system, and steam play a vital role to
live up the systems. Fuel system, Engine cooling system,
Oily water and sludge discharge system, different module
such as HFO Separator, Lube oil separator , HT preheating
, Booster module , Fuel filter module etc completely
depends upon heating. Steam is a easy solution for
heating. When the power plant remain stand by or under
maintenance auxiliary boiler used to produce and supply
saturated steam to all those systems and components.
24/06/2020
Prepared By: Ajoy Das

3. General Consideration for selection of
Auxiliary Boiler
The selection of auxiliary boiler depends upon several facts
in HFO power plant:
 Power plant plant size.
 Systems/Components required for heating.
 Required pressure.
 Considering heat loss in the system.
 Fuel for boiler.
 Boiler efficiency.
 Operation cost.
24/06/2020
Prepared By: Ajoy Das

4. Boiler Efficiency
• Boiler efficiency,ȵ=
𝐻𝑒𝑎𝑡 𝑎𝑐𝑡𝑢𝑎𝑙𝑙𝑦 𝑢𝑠𝑒𝑑 𝑖𝑛 𝑝𝑟𝑜𝑑𝑢𝑐𝑖𝑛𝑔 𝑠𝑡𝑒𝑎𝑚
𝐻𝑒𝑎𝑡 𝑙𝑖𝑏𝑒𝑟𝑎𝑡𝑒𝑑 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑢𝑟𝑛𝑎𝑐𝑒
=
𝑚𝑒 (ℎ−ℎ𝑓1)
𝐶
Here, me= mass of water actually evaporated or steam produced in kg/h or kg/kg of fuel
burnt
C= Calorific value of fuel in KJ/Kg of fuel
h=enthalpy or total heat of steam in Kj/Kg of steam corresponding to a given working
pressure(From Steam table)
hf1=enthalpy or sensible heat of feed water in Kj/Kg of steam corresponding to t1◦C (From
Steam table)
If ms=Total mass of water evaporated into steam in kg
mf=Mass of fuel used in kg
Then me=
𝑚𝑠
𝑚𝑓
So, ȵ=
𝑚𝑠 (ℎ−ℎ𝑓1)
𝑚𝑓×𝐶
=
1500×(2756−334.96)
93×42696
(For 1.5 ton) or ȵ=
1500×(2756−334.96)
93×42696
(For 3 ton)
= .9145×100% =.9145×100%
= 91.45% = 91.45%
.
24/06/2020
Prepared By: Ajoy Das

5. 24/06/2020
Prepared By: Ajoy Das

6. 24/06/2020
Prepared By: Ajoy Das

7. Fuel Consumption of
boiler
• Fuel consumption by boiler capacity, q=
𝑃
µ×𝑄
Here, P= boiler capacity, KW
µ= boiler efficiency,0.80-0.95
Q= Heat value, Kwh/kg
[Heat value for light fuel is approximately 11.86 kwh/kg or 42696 Kj/Kg]
and [Heat value for heavy fuel oil is approximately 11.22 kwh/kg]
q= Fuel demand, Kg/hr
So, fuel consumption, q=
1000
.90×11.86
kg (For 1.5 ton) and q=
2000
.90×11.86
kg ( For 3 ton)
=93.68 Kg (For 1.5 ton) and 187.37 kg (For 3 ton)
24/06/2020
Prepared By: Ajoy Das

8. Flow rate calculation
Boiler (kg/hr) calculation, ms=
𝑃
ℎ𝑒
Here, ms=Steam flow rate, kg/hr
P= load in kw (1kw=1kj/s)
he= Specific enthalpy of evaporation
So, ms =
1000 𝑘𝑗/𝑠
2762 𝑘𝑗/𝑘𝑔
(For 1.5 ton) or
2000 𝑘𝑗/𝑠
2762 𝑘𝑗/𝑘𝑔
(for 3 ton)
=
1000 𝑘𝑔
2762 𝑠
=
2000 𝑘𝑔
2762 𝑠
=
1000
2762 ×
1
3600
𝐾𝑔
ℎ𝑟
=
2000
2762×
1
3600
𝑘𝑔
ℎ𝑟
=
1000×3600
2762
kg/hr =
2000×3600
2762
kg/hr
=1303.40 kg/hr =2606.806 kg/hr
24/06/2020
Prepared By: Ajoy Das

9. Auxiliary Boiler-01(1.5 Ton/Hr)
Starting Procedure
 Make sure that
• Diesel (FUEL) tank level is above 30% (1200 Ltrs)
• All Steam & Condensate header is de-pressurised / drained
• All FUEL inlet & return line as well as inlet quick shut off V/V is open
• Boiler Feed Water tank level is above 70% & all make up water V/Vs are open
• Steam delivery V/V is closed
• Panel Power Switch is on
 Selector Switches
• Auxiliary Boiler Selector Switch in Local (For manual operation) or in Remote (Control from
SCADA)
• Out of 2 Feed water P/Ps, put One P/P in ‘Run’ & other P/P in ‘St-by’
• Out of 2 Container Fan, put One in ‘Run’ & other one in ‘0’
• If the Boiler drum water temp is below 110°C, open the vent line (for temp above 110°C, it’s not
necessary)
• Turn the Burner selector switch in Position- ‘1’, after reaching the steam pressure in 3-4 bar &
water drum temp is above 110°C switch it into Position-‘2’ (Auto mode) and close the vent line. (If
the Boiler drum temp would found above 110°C, directly switch it into Position -‘2’ )
• After reaching the steam pressure 7 bar, uniformly / slowly open the steam delivery V/V.
24/06/2020
Prepared By: Ajoy Das

10. Procedures
 Stopping Procedure: (Manual)
• Turn the Burner selector switch in Position- ‘0’
• Turn Auxiliary Boiler Selector Switch in ‘0’
• Put both Feed water P/Ps in ‘0’
• Put both Container fan in ‘0’
• Boiler Steam Delivery line kept off.
 Reset Procedure:
• After sudden Power source cut off, turn the Fuel Shut off V/V open & then
press the ‘Reset’ button on the Aux. Boiler Control Panel to be re-started
 Blow down Procedure:
• Bottom Blow down need to perform 3 times/day (Duration- 10 Sec)
• Scum Blow down need to perform 1 time/ day (Duration- 5 Sec)
• Sight Glass Blow down need to perform before & after Boiler Operation (1
time/ day)
24/06/2020
Prepared By: Ajoy Das

11. Auxiliary Boiler-02 (3 Ton/Hr)
Starting Procedure
 Make sure that
• Diesel (FUEL) tank level is above 30% (1200 Ltrs)
• All Steam & Condensate header is de-pressurised / drained
• All FUEL inlet & return line as well as inlet quick shut off V/V is open
• Boiler Feed Water tank level is above 70% & all make up water V/Vs are open
• Steam delivery V/V is closed
• Panel Power Switch is on
 Selector Switches
• Auxiliary Boiler Selector Switch in ‘AUTO’
• Out of 2 Feed water P/Ps, put One P/P in ‘Run’ & other P/P in ‘St-by’
• Out of 2 Container Fan, put One in ‘Run’ & other one in ‘0’
• If the Boiler drum water temp is below 110°C, open the vent line (for temp above 110°C, it’s
not necessary)
• Turn the Burner selector switch in Position- ‘1’ & then ‘3’, after reaching the steam
pressure in 3-4 bar & water drum temp is above 110°C switch it into Position-‘2’(Auto
mode) and close the vent line.(If the Boiler drum temp would found above 110°C, directly
switch it into Position -‘2’)
• After reaching the steam pressure 7 bar, uniformly / slowly open the steam delivery V/V.
24/06/2020
Prepared By: Ajoy Das

12. Procedures
 Stopping Procedure: (Manual)
• Turn the Burner selector switch in Position- ‘0’
• Turn Auxiliary Boiler Selector Switch in ‘OFF’
• Put both Feed water P/Ps in ‘0’
• Put both Container fan in ‘0’
• Boiler Steam Delivery line kept off.
 Reset Procedure:
• After sudden Power source cut off, turn the Fuel Shut off V/V open &
then press the ‘Reset’ button on the Aux. Boiler Control Panel to be re-
started.
 Blow down Procedure:
• Bottom Blow down need to perform 3 times/day (Duration- 10 Sec)
• Scum Blow down need to perform 1 time/ day (Duration- 5 Sec)
• Sight Glass Blow down need to perform before & after Boiler Operation
(1 time/ day)
24/06/2020
Prepared By: Ajoy Das

13. Flow Diagram for Checking before starting the boiler
Are the starting conditions met?
Rectify Problem
Check up the Panel Power, SP burner, feed water level, and steam & fuel valve
•
Burner “Auto” and keep the selection switch in position “1” & then “3”
Wait for boiler temperature & pressure
After reaching pressure 3-4 bar & temp. above 110◦c turn it position “2”
Auto Start Boiler
Check All Parameters
Observe smoke, steam pressure, fuel & feed water level as per required level
If Yes
If No
24/06/2020
Prepared By: Ajoy Das

14. Panel Identification (Aux.
Boiler-02)
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Prepared By: Ajoy Das

15. Importance of Boiler blow down
The water which is circulated inside the boiler tubes and drum contains Total
Dissolved Solids (TDS) along with other dissolved and suspended solids.
Substances that remain suspended in water and do not dissolve in it are called
suspended solids usually mineral or organic in origin. Substance that are
dissolved in water and can not seen by naked eye are called dissolved solids.
Dissolved solids generally include sulfates and chlorides of sodium,
magnesium, potassium and calcium and these are mainly responsible for water
hardness.
Increase in the TDS concentration in boiler feed water tank leads to increased
scale formation or deposition on the tube surface, which acts as a resistance in
transferring heat from flue gases to the water, which further leads to
overheating of the tubes. Boiling is a bulk phenomenon that occurs throughout
the liquid , so at initial stages bubbles are formed and then these bubbles reach
the surface of the water and detach themselves from the surface. Due to the
presence of TDS in water, these solids are carried over with the bubbles
formed during boiling which reduces the heat transfer rates and more fuel will
be needed to convert water into steam thereby reducing the boiler efficiency.
Carryover of these solids with the steam reduces the quality of steam and also
damages the control valves, heat exchangers and steam traps placed in the
steam line.
24/06/2020
Prepared By: Ajoy Das

16. Advantages of boiler
blowdown:
• Blow down of boiler water at regular intervals keeps the total
dissolved solid impurities under the rated limits
• The process helps in preventing corrosion as it removes the
impurities which accelerate the corrosion process
• It helps in preventing scaling of boiler tubes and internal
surface
• It prevents the carryover of impurities and contaminants with
the steam, providing the pure steam
• It prevents scaling of internal parts of the heat exchanger
where the pure steam goes as a heating medium
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Prepared By: Ajoy Das

17. Disadvantages of boiler
blowdown:
• If the procedure is not done correctly with the determined
schedule, the blow down of boiler water tends to increase the
heat as well as pressure losses.
• The heat and pressure losses from the boiler water blow down
will reduce boiler efficiency.
• If the blow down arrangement is manual, additional work
hours needed to conduct the operation
24/06/2020
Prepared By: Ajoy Das

18. Scum & Bottom Blow
Down
• Scum blow down ( surface blow down ): To
remove accumulated, suspended and floating
solids, impurities and also remove dissolved
solid concentration, they hinder the formation
of steam.
• Bottom blow down: To remove suspended
solids and residual sludge that have settled at
the bottom.
If these contaminants are not removed regularly
they will build up until they hinder the circulation
patterns
24/06/2020
Prepared By: Ajoy Das

19. Sight Glass blow down
Boiler Sight glass needs to be blow
down regularly, to make sure that it is
showing the correct / actual level,
quality and there is no blockage in the
line of water and steam. This is also to
check that, water and steam cocks are
not leaking. This is a physical mean of
showing the correct level of water in the
boiler.
24/06/2020
Prepared By: Ajoy Das

20. To minimize Boiler Blow
down
• Chemical Treatment:
The main aim of doing a boiler blow down is to reduce the dissolved
impurities in the boiler water, which leads to scale formation.
The scale formation will directly lead to heat transfer within the internal
surface of the boiler leading to a reduction in boiler efficiency.
If the boiler water can be tested regularly and accordingly treated
effectively using various chemicals in the hot well, the feed water will have
fewer impurities making it good for the use.
The need for the boiler blow down will in turn reduce leading to saving of
water and reduction in heat and pressure losses.
• Introduce Auto blow down system:
With an increase in boiler blow down, the water and fuel consumption of the
boiler water will increase. The best practice is to remove the manual blow
down system and to install an automatic boiler water measurement and blow
down system.
24/06/2020
Prepared By: Ajoy Das

21. Feed Water Maintained
Quality
Test Parameters Standard Value
pH at 25°C 9.0 – 11.5
TDS Max. 3000ppm
PAlkalinity as CaCo3 10 – 300ppm
Hardness <2ppm
Chloride as Cl- <200ppm
24/06/2020
Prepared By: Ajoy Das

22. Removing Dissolved
Oxygen
A deaerator is a device that removes oxygen
and other dissolved gases from liquids.
Deaerators are commonly used to remove
dissolved gases in feed water for steam-
generating boilers. Dissolved oxygen in feed
water will cause serious corrosion damage in
a boiler by attaching to the walls of metal
piping and other equipment and
forming oxides (like rust). Dissolved carbon
dioxide combines with water to
form carbonic acid that may cause further
corrosion. Most deaerators are designed to
remove oxygen down to levels of 7 ppb by
weight or less, as well as essentially
eliminating carbon dioxide.
24/06/2020
Prepared By: Ajoy Das

23. The Causes & Effects of
Steam Hammer
 Steam hammering is the phenomenon which
occurs in steam charging in the pipeline while
there is a presence of condensate in the line. This
is because of sudden drop in pressure of steam as
it comes in contact of condensate.
 This can also occur due to poor heating of steam
network before the steam enters into the system.
Piping network remains cool and as soon as the
hot steam enters, condensation takes place and
water gets accumulated in the lines forming a
Slug. As the steam flow increases, steam carries
the water with it and lot of momentum is created
and it hammers the line loops with tremendous
forces creating a lot of stress. Steam hammers can
blow flange joints and can damage piping
supports and even piping itself.
24/06/2020
Prepared By: Ajoy Das

24. Loading Procedure
• During startup air control damper position will be 80 % for purging
air. After that, the damper condition will down to 15~20% to ignite.
When proper flame will be achieved, the damper position will be
increased to 75% to meet the set point load. The burner flame will
be bluish of proper lean burning and there will be no dark smoke
through the chimney. After reaching the set point burner will be
stopped. During stop, it will do post purging to reduce the
temperature of the combustion chamber.
• At present, the upper limit / stopping limit of steam pressure is set to
7.3 bar and lower limit/ starting limit is set to 7.0 bar.(Stage-01)
• And the upper limit / stopping limit of steam pressure is set to 7.1
bar and lower limit/ starting limit is set to 6.8 bar.(Stage-02)
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Prepared By: Ajoy Das

25. Burner Operation Position
Minimum Load Servomotor appr. 10◦
Maximum Load Servomotor appr. 130◦
Burner Stopped Servomotor appr. 0◦; air dampers closed
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26. Check the flame pattern:
 Lack of air ( Dirty orange flame color)
 Excessive air ( Very short or, light flame)
- Fig: Flame pattern of correct A/F ratio
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27. Fig: Rich burn Fig: Lean burn
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28. Burner controller:
The burner controller which controls the whole
process.
Servo Motor:
Servo motor is controlled by burner controller
which controls the air damper, fuel amount
during low load & full load which is set into the
limit switch. Servo motor is connected with the
cam strip and oil flow controller.
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Prepared By: Ajoy Das

29. Cam Strip:
These controls the air control damper and fuel
amount of the burner.
Safety Valve:
Opening: 11.0 bar.
Closing: 10.4 bar
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Prepared By: Ajoy Das

30. Oil Pump:
Produce the fuel supply pressure. Pressure shows at
Manometer
Motor:
The burner motor which drives the fan and oil pump
starts. Amps consumed rotating as per command.
24/06/2020
Prepared By: Ajoy Das

31. Pressure Limit Switch:
These are upper limit and lower limit of steam
pressure switches which are responsible to auto
stop & auto start the burner.
Photocell:
Photocell which monitors the burner flame.
24/06/2020
Prepared By: Ajoy Das

32. Problems
1) Burner doesn’t start
i. No voltage supply
ii. Control circuit interrupted
iii. Controller defective
2) Oil pump doesn’t convey oil
i. Fan motor is not running
ii. Manually operated shut-off valve closed
iii. Controller defective
iv. Fuel pump filter clogged
v. Suction line leaky
3) Fan motor starts, at max pre-purge position, a safety shut off is triggered
i. Coupling of fan motor/oil pump damaged
ii. Fan dirty
iii. Copper tube of pressure monitor for combustion air dirty
4) Purge period doesn’t start
i. Limit switch full load setting not activated (servomotor)
• 24/06/2020
Prepared By: Ajoy Das

33. 5) Ignition spark doesn’t form
i. No voltage on ignition transformer
ii. Ignition electrode too far away
iii. Ignition electrodes or, ignition line have ground contact
iv. Ignition transformer defective
6) Ignition sparks forms, shut-off before formation of flame
i. Oil safety interlock circuit open
ii. Oil solenoid valve does not open
iii. Setting of A/F ratio not ok
7) Ignition is ok, fault after formation of flame
i. Flame scanner dirty
ii. Flame scanner defective
iii. Flame signal too weak
24/06/2020
Prepared By: Ajoy Das

34. • 8) Flame forms, shut-off when running up to full load
i. Soiled filter
ii. Oil pressure monitors set incorrectly
9) Unsatisfactory combustion / Black smoke
i. Oil nozzle defective or, dirty
10) Burner fault alarm:
i. Electrode too far
ii. Fouled / damaged electrode
iii. Insufficient voltage
iv. Fouled photocell or, damaged
v. Incorrect A/F ratio
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Prepared By: Ajoy Das

35. Thanks to all
24/06/2020
Prepared By: Ajoy Das