A Brief Introduction to Boilers

Brief Introduction
1
SatyakamMohapatra
Engineer(Mechanical)
Monnet Power Company Ltd

BOILER
In General, A boiler is a closed pressure vessel strongly
constructed of steel or iron where water is converted to steam
by application of heat.
According Indian Boilers Act, 1923, -
“Boiler" means a pressure vessel in which steam is generated for
use external to itself by application of heat which is wholly or
partly under pressure when steam is shut off but does not
include a pressure vessel,-
(i) with capacity less than 25 litres (such capacity being measured
from the feed check valve to the main steam stop valve);
(ii) with less than one kilogram per centimetre square design
gauge pressure and working gauge pressure; or
(iii) in which water is heated below one hundred degrees centi-grade;
Monnet Power Company Ltd 2

Usage of Boiler
 In Power Sectors
 In Independent Power Plant(IPP) &
Captive Power Plant(CPP).
 In Process Plants
 In Oil Refineries, Paper Industry, Sugar
Industry, Chemical Industry, Rice mill,
Steel Industry etc.

Criteria Types
Content of Tube Fire Tube Boiler, Water Tube Boiler
Type of firing Solid, Liquid & Gas Fired
Type of Circulation Natural Circulation, Natural Assisted or
Controlled Circulation, Forced
Circulation
Steam Pressure Sub Critical Boiler, Super Critical Boiler
Draught Natural Draught, Mechanized
Draught(Forced, Induced, Balanced)

Content of Tubes
Fire Tube Water Tube
In fire tube boiler hot flue
gas will be moved inside the
tubes & water outside the
tube.
In fire tube boiler mode of
firing is generally internally
fired.
In fire tube boiler operating
pressure limited to 25 kg/cm²
In water tube boiler
water will be moved
inside the tube & hot flue
gases outside the tubes.
Mode of firing is
externally fired.
Operating pressure can
exceed 125 kg/cm² or
more

FIRE TUBE
BOILER
WATER TUBE
BOILER

Type of Firing
Solid Liquid Gas
AFBC CFBC PC Fired WHRB
Atmospheric
Fluidized Bed
Combustion
Bed Material Used
– Crushed
Refractory( + 0.8
mm to -2.8 mm)
Velocity – 3-5
m/sec
Coal – F-Grade,
Washery Reject
Combustion Eff-
80-85%
Circulating
Fluidized Bed
Combustion
Bed Material Used -
Crushed Refractory (
+ 0.8 mm to -2.8 mm)
 Velocity – 7-8 m/s.
Coal – F-Grade,
Washery Reject
 Combustion Eff.-
95 %
Waste Heat
Recovery Boiler
Waste Heat
from Flue Gas
of Other
process used in
boiler for Steam
generation
Pulverized
Coal Fired
Boiler.
Coal : F
Grade(3000-
3500 Kcal/Kg)
Size is 65μto
80μ.
No Bed is
Required
Combustion
Eff : 99 %

AFBC CFBC
WHRB PC Fired

Type of Circulation
Natural
Circulation
Forced
Circulation
Assisted/Controlled
Circulation
Density
Difference is the
driving force.
Limited to boiler
with drum
operating
pressure around
175 kg/cm2(g).
Mechanical
pumps are used to
over come the
frictional losses
Operating
pressure is above
224.6 kg/cm2(g)
Beyond 175 kg/cm2(g)
pressure in a re circulation
system, circulation through
the evaporator is to be
assisted with mechanical
pumps to overcome
frictional losses in the
tubes. A pump called boiler
circulation pump will be
placed in the down comer
between the Drum & water
wall ring header to do this
function is called
controlled circulation.

SH
ECO Drum ECO
Drum
SH
Furnace
Wall
Furnace
Wall
Distribution
Header
Distribution
Header
CC
Pump
Natural
Circulation
SH
Forced Circulation
Assisted
Circulation
BCP
Economiser
WW
Separator
Water
from
Feed
Station

Steam Pressure
Sub Critical Boiler Super Critical Boiler
Boilers Operating below the
Critical Pressure(224.6
kg/cm2(g)).
These are recirculation type or
once through .
Steam Drum is required to
separate water & steam.
Boilers Operating above Critical
Pressure (224.6 kg/cm2(g)) &
Critical Temp (374 0C)
These are only Once Through
Type.
Drum is not required as cycle
medium is a single phase fluid
having homogenous property.

DRAUGHT
Natural Draught Mechanized Draught
The draught
required for the flow
of air & gas inside
the boiler is created
by chimney alone
Forced Induced Balanced
Here Fans are
used to draw air
from atmosphere
& push into the
furnace.
The entire boiler
will be kept
above
atmospheric
pressure
Fans installed at
the outlet of
boiler, evacuate
the gases from
furnace. So a
negative Pr. Is
developed in
furnace & air from
atmosphere enters
the furnace
Both Forced
& Induced
draught fans
are used to
derive the
benefits of
both systems.

Boiler Mountings
 Safety Valves
 Feed Check Valves
 Pressure Gauge
 Drum Water Level gauge
 Blow Down Valve
 Main Stop Valve…etc
Boiler Mounting are basically used for safe operation of
Boiler.

Description of Boiler Mountings
 Safety Valve : The Function of a safety valve is to blow off steam when the pressure in
the boiler exceeds the working pressure.
 Feed Check Valve : A feed check valve is used to control the supply of feed water to
boiler & also to act as a non-return valve.
 Pressure Gauge : Pressure gauge indicates the pressure of steam in a boiler.
 Drum Water Level Gauge : The Function of water gauge glass is to indicate the water
level in the Drum.
 Blow Down Valve : Blow down Valves are designed for continuous use to control the
concentration of dissolved solids in boiler water.
 Main Stop Valve : Function of a steam stop valve is to stop or allow the flow of steam
from the boiler to Main Steam line.

 Maker : Bharat Heavy Electricals Ltd
 BoilerMaker No : 0675,0676
 Type : Controlled Circulation, Sub Critical, Two Pass, Single Reheat,
Balance draught,Tangential PC Fired.
 Boiler Rating : 51793m2
 Boiler Drum Design Pressure : 210 kg/cm2(g)
 Boiler Hydrotest Pressure : 315 kg/cm2(g) ,(For RH-78 kg/cm2(g) )
 Boiler DrumDesignTemp : 369 OC
 Steam flow at SHO: 1700TPH
 Steam pressure at SHO: 192.2 kg/cm2(g)
 Steam temperature at SHO: 540OC
 Reheat Steam flow: 1468.1TPH
 Steampressure at RHI: 52.4 kg/cm2(g)
 Steam temperature at RHI: 337OC
 Steam pressure at RHO: 52.4 kg/cm2(g)
 Steam temperature at RHO: 540OC
 Boiler Efficiency: Monnet P8o6we%r Company Ltd 15

Boiler Pressure parts
The Following parts generally comes under this category –
• Drum
 Economiser
 Water Walls
 Radiant Roof Tubes
 Steam Cooled Walls
 LTSH Coil
 Div Panelette SH
 Platen SH
 Rehaeter Coil Assy.

17
RH O/L Hdr

Water Circuit
ECO Feed
Pipe
ECO I/L
Header
ECO Coil
ECO O/L
Header
ECO
Link
DRUM
Down
Comer
Bottom
Ring
Header
Water
Wall
Tubes
Water Wall
Outlet
Headers
Feed
Water
Station

BOILER DRUM
 In a Sub-Critical re-circulation boiler, the drum plays an
important role. In the erection of a Power Boiler, the lifting of
the Boiler Drum is the first mile stone activity.
 The Functions of Drum are
 Separation of saturated steam from the steam- water mixture
produced by evaporating tubes.
 Mixing feed water from economiser and water separated from steam-water
mixture, and re-circulate through the evaporating tubes
 Carrying out blow down for reduction of boiler water dissolved solid
concentration.
 Treatment of Boiler Water by chemicals
20

TECHNICAL DATA OF DRUM
Design Pressure 210 kg/cm2(g)
Operating Pressure 197 kg/cm2(g)
Water Holding Capacity 60 m3
Design Temperature 369 0C
No of Cyclone Separator 92(46X2)
No of Secondary Drier 124
OD of Drum 1778 mm
Thickness
(Straight Portion/Dished Portion)
155 mm
Weight of Drum without Internals 214.7 MT 21

Feed
Nozzle
DC
Nozzle
Safety
Valve
Stub
SH
Conn
Pipe
Stubs
Riser
Stub
1
2
Taping No Details Qty(In Nos)
1 DWLG & EWLI 15 (Both Side)
2 Test Tapings 4
3 Air Vent 2
4 Chemical Feed Nozzle 1
5 DWLG & EWLI 15 (Both Side)
6 CBD 1
3
4
5
6
22

The main components of Boiler Drum:
 Turbo separator
 Screen Dryer
 Baffle Plate
 Anti Vertex Spider
STAGES OF STEAM & WATER SEPARATION :
 Separation takes place in the concentric cylinder of Turbo separator.
 The second stage of separation takes place in the corrugated sheets
connected to the top of the Turbo separator.
 The third and final stage of separation takes place in Screen Driers.
 The Anti Vertex spider is provided at the inlet of Down comer to avoid
whirl formation in DC.
23

Turbo
Separator
(2X46)
Drum Internals of MPCL Boiler
Separating
Chamber
Drier Assembly(62X2)
Feed Header
Feed Nozzle
DC Nozzle Monnet Power Company Ltd
24

TURBO SEPERATOR

Economiser System
O Application of economisers is to capture the heat from flue
gas and transfer it to the feed water. This raises the
temperature of the boiler feed water, lowering the needed
energy input, in turn increases efficiency.
O Total System Consists of ECO feed line, Eco I/L Header, ECO
Coil Assy, ECO O/L Hdr, ECO Link to Drum.
TECHNICAL DATA
No of Banks 3 Banks( 92 Sets)
Total Heating Surface of
ECO System
20,000 Sq. Mtr
Total Water Holding
Capacity
150 m3

Description Size
(DiaXThick)
(In mm)
Design Temp( 0C) Design Pressure
(kg/cm2(g))
ECO Feed Pipe 457.2X50 283 219.7
ECO Inlet Header 508X65 283 215
ECO Coil 38.1X4.5 336 215
ECO Outlet
Header
406.4X60 353 210.8
ECO Link to
Drum
368X40
323.9X36
357 210.8

ECONOMISER COIL

Water Wall System
O The water walls are tube panels through which the
water for steam generation will be circulated. In
Water Wall only heat is added to evaporate the feed
water to steam.
O It also forms the major part of furnace enclosure.
TECHNICAL DATA
Design Temp & Pr. at WW
Inlet Hdr
3680C & 212 kg/cm2(g)
Design Temp & Pr. at WW
Outlet Hdr
3680C & 209 kg/cm2(g)
Total Heating Surface of WW
Tubes
7000 Sq.Mtr
Water Holding Capacity of
Circulating System
170 m3

Description Size
(DiaXThck)
(In mm)
(kg/cm2(g))
Down Comer 368X36 368 212
Bottom Ring
Header
914X85 368 212
WW Tubes 51X5.6/6.0/7.1
63.5X7.1
396 214
Front, Hanger Tube &
Screen Tube O/L
Header
273X40 368 209
Side WW O/L
Header
273X50 368 209
Riser Pipes 159X18 368 209

WW
Panels
Div
SH
Panel
Platen
SH

CC PUMP
Boiler water circulating pump is used in
high capacity boiler (Super critical or Sub
critical), It assists the circulation of water, to
overcome the friction losses in Boiler.
Make : Torishima
Type : Single Suction-Double discharge
No of Pumps : Three
Design pressure : 210 kg/cm2(g)
Hydr0 test pressure : 315 kg/cm2(g)
Design Temperature : 366 oC
Motor Rating : 350 KW
Full Load Speed : 1450 rpm
Suction Pressure : 197kg/cm2(g)
Quantity Pumped : 48453 l/min(2850 tph)
Wt. of Motor : 7300 kg
Wt. of Pump casing : 5200 kg

Saturated Steam Circuit
Sat Steam
DRUM
Rad Roof
SH Conn I/L Hdr
Pipes
Fur Roof
Panel
SH Roof
O/L Hdr
BP L/R Side
Upp Hdr
BP L/R
Side Wall
Panel
SH BP
Lower Side
Front Hdr
BP Front
Lower
Hdr
BP Front
Wall
SH Rear
Roof
Tubes
Junction
Hdr
BP Upper
Rear Wall
ECO
Support
Tube
SH Rear
Int. Hdr
SH Rear
Hanger
Tube
LTSH I/L
Hdr
BP Lower
Side Rear
Hdr
BP Lower
Rear Hdr
BP Lower
Rear Wall
Risers

Saturated Steam Circulation System
Description Size
(DiaXThick)
(In mm)
Design Temp
( 0C)
Design Pressure
(kg/cm2(g))
Rad Roof Inlet Header 273X50 369 208.8
Fur Roof Panel 57X6.0 414 208.8
Rad Roof O/L Hdr 406.4X55 369 208.2
BP L/R Side I/L. Hdr 368X48 368 208.0
BP L/R Side Panel 63.5X6.3/7.1.
51.0X5.0/5.6
393 208.0
SH BP Lower Side
Front Hdr
406.4X60 393 207.4
SH BP Front Lower Hdr 406.4X60 393 207.4
BP Front Wall 51X5.0/5.6
63.5/6.3
393 207.4
BP Front Hanger Tubes 51X6.3 394 207.4
Monnet Power Company Ltd Contd.. 34

Description Size
(DiaXThck)
(In mm)
Design Temp
( 0C)
Design Pressure
(kg/cm2(g))
SH Rear Roof Panel 51X5 394 206.8
SH Rear Junction Hdr 273X50 395 206.7
BP Rear Upper Wall 51X5 395 206.7
BP Lower Side Rear Hdr 323.9X50 393 206.3
BP Lower Rear Hdr 323.9X45 393 206.3
BP Rear Lower Panel 44.5X5 394 206.3
ECO Support Tubes 44.5X7.1 393 207.4
SH Inter. Hdr 219.1X28 393 207.3
SH Hanger Tubes 51X11 394 207.2
• Total Heating Surface of SH Roof – 830 Sq Mtr
• Total Heating Surface of Steam Cooled Wall – 2010 Sq. Mtr

Superheated Steam Circuit
LTSH
I/L Hdr
LTSH
Coil
SH DESH
Link
Div SH
I/L Hdr
LTSH
O/L Hdr
SH Div
Panelette
Assy
Div SH
O/L Hdr
SH Div
Panel O/L
Links
SH Vertical
Platen I/L
Hdr
SH Vertical
Platen Assy
SH Platen
O/L Hdr
MS Line
HP
Turbine
MS Line

Super Heater System
O Superheater is a component of a boiler that superheats steam i.e. heats
steam above its saturation temperature. Superheated steam contains
more thermal energy and increases the overall efficiency of the cycle.
O There are 3 stages of Super Heaters – LTSH, Divisional Panelette SH &
Platen Super Heater.
TECHNICAL DATA
No of Sets LTSH-62 Sets, Divisional SH- 24 Sets,
Platen SH – 25 Sets
Total Heating Surface LTSH -10,100 m2, Div SH -2025 m2,
Platen SH – 2200 m2
Total Water Holding Capacity of SH
system
130 m3

Superheater System
Description Size
(DiaXThick)
(In mm)
(kg/cm2(g))
LTSH I/L Hdr 323.9X50 395 205.8
LTSH Horizontal
Assy.
47.63X5.6 445 205.8
LTSH Terminal Tube
Assy
47.63X5.6 464 205.8
LTSH O/L Hdr 457.2x65 435 204.2
SH DESH Link 508x60
558x60
440
426
204.0
SH Div I/L Hdr 406.4X60 419 202.8
Monnet Power Company Ltd Contd.. 38

Description Size
(DiaXThick)
(In mm)
(kg/cm2(g))
SH Div. Panelette
Assy
44.5X5
44.5X7.1
483/
522
202.8
Div. SH O/L Hdr 406.4X70 487 198.9
SH Div Panel O/L
Link
508X60 487 198.6
SH Vertical Platen
I/L Hdr
406.4X60 487 197.4
SH Vertical Platen
Assy
63.5X6.3/12
51X6.3/11
476/533
476/551
197.4
SH Platen O/L Hdr 508X110 540 192.2

LTSH COIL

Div SH Panel

Platen SH

Reheater Circuit
RH I/L
Hdr
RH Coil
Assy
RH O/L Hdr (R)
From
HP
Turbine
Exhaust
CRH
Line
HRH
Line
IP
Turbine
RH O/L Hdr (F)

Reheater System
O Reheater is a boiler component in which heat is added to
intermediate-pressure steam, which has lost some of its
energy in expansion through the high-pressure turbine.
O Reheater System comprises of : RH Inlet Header, RH Front
Platen Coil Assy, RH Rear Spaced Assy, RH Outlet Header
TECHNICAL DATA
No of RH Coil Assy 74 Sets (Both Front & Rear)
Total Heating Surface of RH Coils 7628 Sq. Mtr
Total Water Holding Capacity of RH 105 m3
Design Temp. & Pr. at RH Inlet Hdr 361 0C ,52.4 kg/cm2(g)
Design Temp. & Pr. at RH Outlet Hdr 540 0C,52.4 kg/cm2(g)
Size of RH front Coil Assy 63.5 mm Dia X 4 mm Thck
54 mm Dia X 4.5 mm Thck
Size of RH Rear Coil Assy 54 mm Dia X 4.5 mm Thck

RH Coil Assy

WATER
SATURATED STEAM
SUPER HEATED STEAM
REHEATED STEAM
M.S
H.
R.
C.R.H H
FROM F.C.S
CC
Pump
Div SH
Platen
SH
RH
Coil
Assy
ECO Coil
Boiler
Drum
DC
Furnace Wall
Bottom Ring Header
LTSH

Air Flow path
PA Fan FD Fan FD Fan PA Fan
Pri.
Side
Sec
Side
APH
SCAPH SCAPH
Hot PA Wind Box
to Mill
Hot PA
to Mill
Cold
PA
to
Mill
Cold
PA
to
Mill
Scanner
Air fan
Flue
Gas
Sec.
Side
Pri.
Side
Flue
Gas
APH

Forced Draught Fan
• These fans supply air necessary for fuel combustion for proper
burning of the specific fuel. These are generally axial type.
• The FD fans supply secondary & over fire air, which is preheated in
secondary sector APH.
• Over fire air can be admitted to the furnace through the upper
levels of furnace wind box nozzle to assist in reducing the amount
of NOx formed in furnace.
• Control of airflow to WB is effected by FD fan blade pitch control
& distribution of secondary air to WB compartments is controlled
by secondary air damper.
• Steam Coil Air Pre Heater(SCAPH) are provided in the by pass
ducts before each APH to prevent corrosion of cold end of APH
normally at start up & low load operation.

Blades
Forced Draught Fan
Suction
Chamber
Diffuser

Primary air fan
 These fans supply the air needed to dry & transport coal from
coal mills to the furnace. These fans are generally axial type of
fan.
• To achieve the required temperature at mill inlets(For Proper
Drying of Coal) , part of air(Tempering air) by passes the APH &
is mixed with hot air coming out of APH.
 The PA Fan blade pitch is modulated to maintain a pre
determined pressure in pulveriser hot air bus duct.
 Mill Air flow is maintained by adjusting the hot air regulating
damper while the mill outlet temp is maintained by adjusting the
cold air regulator damper. Venturi is provided in the mill inlet
duct to measure the individual mill air flow.

Suction
Chamber
Diffuser Assy.
Primary Air Fan

1st Stage
Blade
2nd Stage
Blade
Primary Air Fan

Technical specification of Fans
Description Unit PA Fan FD Fan
Make N.A. BHEL BHEL
Type N.A. PAF 19/10.6-2 FAF 23/12.5-1
Motor Rating KW 3600 1200
Capacity M3/Hr 105 215
Speed rpm 1490 990
Pressure mmwc 1290 410
Temp of Medium
0C 50 50
Handled
Bearing
Lubrication
N.A. Oil Lubrication(ISO
VG68)
Oil Lubrication(ISO
VG68)

Air Pre Heater
 The purpose of APH is to recover heat from the boiler
flue gas & heat air before another process and so as to
increase the thermal efficiency.
Ljungstrom (Regenerative) Air Pre Heater:
 The basic component of Ljungstrom APH is a continuously
rotating cylinder, called rotor, that is packed with
thousands of square feet of specially formed sheets of heat
transfer surface.
 As the Rotor revolves, waste heat is absorbed from the hot
flue gas passing through one half of the structure. The heat
transfer cycle is continuous as the surface are alternatively
exposed to the outgoing gas & incoming air stream.

Technical Data
Description Value
Type Regenerative, Trisector
No per Boiler Two
Rotor Diameter 6789 mm
Arrangement Vertical
Heating Surface Area 84200 M2
Main Drive 18.5 KW,1500 rpm
Aux. Drive Air Motor with gear box & muffler, Air consumption
8 Nm3/min at pressure 6.33 kg/cm2(g)

Soot blowers
 As the flue gas moves over the heat transfer areas of
boiler, the ash deposits on the heating surfaces. This is
known as soot deposit. Soot Blowers are installed to
blow away these soot deposits to facilitate smooth heat
transfer.
 There are two types of Soot Blowers-Wall Blowers &
Long Retractable Soot Blowers.
 Wall Blowers are used to blow off soots deposited in
water walls in furnace
 LRSB are used in Super Heaters, Economiser &
Reheater Zone.

LRSB
59
WALL
BLOWER

60
WALL BLOWER

Technical Data
Description Unit Wall Blower LRSB
No per Boiler No. 88+16(Future) 40+18(Future)
Travel mm 305 9700
Blowing Pressure kg/cm2(g) 11 12.5/10.5
Blowing Steam Temp 0C 383 383
Speed of Travel mpm 6.1 1.55
Speed of Rotary rpm 0.7 5.87
Blowing Rate per group Kg/min 89 152/93/79
Blowing time per group Min 1.4 12.04
Operating time per cycle Min 66 75.12/325.52/100.16
Steam Consumption per cycle Kg 5500 47708
Steam Consumption
Kg 62.5 1192
/Cycle/Blower
Total Steam Consumption per Day Kg 159624
Blowing Steam Temp & Pr. 383 0C & 30 kg/cm2
Cycles per Day No 3 3
Blowing Angle Deg. 3600 3600

LDO & HFO Circuit
14 kg/cm2(g)
Tanker 1
12KL
Tanker 2
12KL
Tanker 3
12KL
Tanker 4
12KL
Tanker 5
12KL
Tanker 6
12KL
HFO
Tank #1
3000 m3
HFO
Tank #2
3000 m3
LDO
Tank#1
1000 m3
LDO
Tank#2
1000 m3
LDO
Pumps
HFO
Pumps
Unloading
Pump
House
Contd..
LDO Unloading Header
HFO Unloading Header
LDO Discharge Line
HFO Discharge Line
Steam Line to Tanks
PRS
250 0C
4.5 kg/cm2(g)
232 0C
Condensate Line to Flash Tank
62
LDO cap.-50m3/hr
& Pr.- 2 Kg/cm2
HFO cap.-50m3/hr
& Pr.- 5 Kg/cm2

LDO & HFO Circuit
LDO
Tank
HFO
Tank
1x100 %
LDO Pump
Set(Both
Units)
HFO Pump
Set(Unit I)
HFO Pump
Set(Unit
II)
HFO
Heater-1
HFO
Heater-2
HFO Drain
System
Boiler I Boiler II
Condensate Line to
Nearest Trench
Aux. Steam
2X1000 m3
2X3000 m3
14 kg/cm2(g)
210 0C
2x100 %
63
Forwarding Pump House
Steam
Tracing
Line
Steam
Tracing
Line

Technical specification of hfo & Ldo
Description Unit LDO HFO
Standard N.A. IS 1460-1974 IS-1593/1971/Gr HV/Oil
Flash Point 0C 66 66
Pumping Temp. 0C 35 55
Firing Temp. 0C 35 120
Viscosity cst 2 to 20 @Firing Temp. 180 at 55 0C
Total Sulphur N.A. 1.8 % by weight 4.5 % by weight
GCV Kcal/kg 10720 10270
Sp. Gravity at 15 0C N.A. 0.85-0.87 0.85-0.95

Technical specification of HFO & LDO Forwarding Pumps
Description Unit LDO Pump HFO Pump
Make N.A. Alekton Alekton
No of Pump per Blr No 01(Common for
Both Unit)
01
Model No. N.A. DH 330-770-3 DH 600-1400-3 SJ
Capacity at max cst lpm 281(14.3 tph) 879(50.1 tph)
Speed rpm 2920 1450
Suction Pressure kg/cm2(g) -0.5 -0.5
Delivery Pressure kg/cm2(g) 25 30
Motor rating KW 18.5 75
Motor Make N.A. Crompton Greaves Crompton Greaves
Bearing Lubrication N.A. Grease IS 719 Gr.3 Grease IS 719 Gr.3
Pump Efficiency(at min cst) % 78 83.7

TT burners assy.
UPPER HFO OIL BURNERS
END
AIR
COAL
OIL+AIR
COAL
AIR
COAL
OIL+AIR
COAL
AIR
COAL
OIL+AIR
COAL
AIR
COAL
OIL+AIR
COAL
END
AIR
OVER FIRE AIR
OVER FIRE AIR
LOWER
HH
H
GH
G
FG
F
EF
E
DE
D
CD
C
BC
B
AB
A
AA
Service Ignition of Pulverised Fuel, Stabilization of
Coal Flame at lower loads etc.
Capacity Maximum 30 % MCR
No of Oil Guns 16(4 per elevation)
Locations Aux air nozzles AB,CD,EF & GH
HFO flow per Gun 2420 kg/hr(Max), 950 kg/hr(Min)
HFO Pressure 10.5 kg/cm2(g)(Max), 4.0 kg/cm2(g)(Min)
Atm. Steam Flow/Gun 250 kg/Hr
At. Steam Pr. 5.25 kg/cm2(g)
LDO OIL BURNERS
Service Initial startup & warm-up.
Capacity Maximum 7.5 % MCR
No of Oil Guns 4(In One Elevation)
Locations Aux air nozzle AB
LDO flow per Gun 2420 kg/hr(Max), 950 kg/hr(Min)
LDO Pressure 10.0 kg/cm2(g)(Max), 3.5 kg/cm2(g)(Min)
Atm. air Flow/Gun 241 kg/ Hr
At. air Pr. 5.25 kg/cm2(g)

Coal Circuit
Coal
Bunker
Pulveriser
To four
corners
of
Boiler
Coal
From
CHP
Feeder

Combustion
Chamber Div SH
Platen
SH
RH
Coil
LTSH
Coil
Economiser
APH
APH
ESP
Pass A
ESP
Pass B
ESP
Pass C
ESP
Pass D
ID
Fan
ID
Fan
C
H
I
M
N
E
Y
Flue gas path
1404 0C 1150 0C 1040 0C 904 0C 7100C
541 0C
1270C
3340C
3340C
127 0C

-79
mmwc
APH
C
H
I
M
N
E
Y
Flue Gas Path
-19 mmwc
-33 mmwc
-5 mmwc ESP
-213
mmwc
-270
mmwc
+32
mmwc

• Electrostatic Precipitator : An electrostatic
precipitator (ESP) is a highly efficient filtration device
that removes fine particles, like dust and smoke, from a
flowing gas using the force of an induced electrostatic
charge minimally impeding the flow of gases through
the unit.
No of pass per boiler : 4
Gas flow at inlet : 566.7 Nm3/s
Temp. at inlet : 127 0C
Dust concentration at inlet : 86.8 gm/Nm3 (Worst Coal),
70.69 gm/Nm3 (Design Coal)
Dust concentration at outlet : 50 mg/Nm3(Worst Coal)
Efficiency : 99.942 %

 Induced Draught Fan : ID Fans evacuate combustion
products from the boiler furnace by creating sufficient
negative pressure to establish a slight suction in
furnace.
Make : BHEL
No per Boiler : Two
Model No. - NDZV 47 SIDOR
Fan Regulation : Inlet damper & VFD
Temp. of Medium : 150 0C
Motor Rating : 3800 KW
Flow : 565 m3/Hr
Draught at Inlet : -270 mmwc
Draught at Outlet : 32 mmwc
Bearing Lubrication : Oil Lubrication(ISO VG68)

Suction
Chamber
Discharge
Chamber
Motor
Impeller
Rear
Side
Bearing
Front
Side
Bearing
INDUCED DRAUGHT FAN

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