BOILER PRESENTATION ON 21.10.14 1.pdf

PRESENTATION COVERS
• INTRODUCTION TO CFBC BOILER
• ADVANTAGES OF CFBC BOIELR
• 150 MW BOILER GENERAL ARRANGEMENT
• WATER & STEAM PATH CIRCUIT
• TECHNICAL DATA
• GENERAL DESCRIPTION OF BOILER
 PRESSURE PARTS
 A). MAINTENANCESCHEDULES
 B) TROUBLE SHOOTING
 C) MATERIALS
 NON PRESSURE PARTS
 A). MAINTENANCESCHEDULES
 B) TROUBLE SHOOTING
 AUXILIARIES

CFBC BOILER INTRODUCTION:
In a circulating fluidized-bed boiler, a portion of combustion air is
introduced through the bottom of the bed. The bed material normally
consists of fuel, limestone and ash. The bottom of the bed is supported
by water-cooled membrane walls with specially designed air nozzles
which distribute the air uniformly. The fuel and limestone (for sulfur
capture) are fed into the lower bed. In the presence of fluidizing air,
the fuel and limestone quickly and uniformly mix under the turbulent
environment and behave like a fluid. Carbon particles in the fuel are
exposed to the combustion air. The balance of combustion air is
introduced at the top of the lower, dense bed. This staged combustion
limits the formation of nitrogen oxides (NO). The bed fluidizing air

velocity is greater than the terminal velocity of most of the particles in
the bed and thus fluidizing air elutriates the particles through the
combustion chamber to the cyclone separators at the furnace exit. The
captured solids, including any unburned carbon and unutilized
calcium oxide (CaO), are re injected directly back into the combustion
chamber without passing through an external recirculation. This
internal solids circulation provides longer residence time for fuel and
limestone, resulting in good combustion and improved sulfur capture.

.
ADVANTAGES OF CFBC BOILER:
1. High Efficiency
2. Reduction in Boiler Size
3. Fuel Flexibility: Fuels like washer rejects, agro waste can be burnt efficiently, Boilers
can fire coals with ash content as high as 62% and having calorific value as low as 2,500
kcal/kg.
4. Pollution Control:SO2 formation can be greatly minimized by addition of limestone
or dolomite for high sulphur coals. Eliminates NOx formation.
5. Low Corrosion and Erosion: are less due to lower combustion temperature,
softness of ash and low particle velocity (of the order of 1 m/sec).
6. No Clinker Formation: Temperature of the furnace is in the range of 750–900o C.
7. No Slagging in the Furnace-No Soot Blowing: volatilization of alkali components
in ash does not take place and the ash is non stocky.

WATER CIRCUIT:
Feed Water Control station
ECO-1
ECO-2
Steam Drum
Water cooled
screens
Down Comers
Water Wall
Pannels

STEAM CIRCUIT:
PSSH Collecting Header O/L
SSSH Common Header I/L
SSSH Collecting Header O/L
HTSH I/L Header
HTSH O/L Header
Main steam outlet
Steam Drum
Right & Left cage wall top header
I/L
Right & Left cage wall bottom header
O/L
Front & Rear cage wall bottom header
I/L
Front & Rear cage wall top header O/L
Middle cage wall top header I/L
Middle cage wall bottom header O/L
PSSH Common Header I/L
Primary Attemperation
Secondary Attemperation

DESIGN FEATURES OF 520 TPH BOILER:
•TYPE OF BOILER : Super high pressure with intermediate re-heat, single
Drum Natural circulation, Circulated fluidized bed combustion.
•FUEL – Option 1. 100% Indian coal (Design coal )
Option 2. 50% Indian coal + 50% Indonesian coal.
Net steaming capacity at mcr firing – 520 tph
Steam pressure at mssv outlet – 14.5 mpa (g)
Steam temperature at super heater outlet – 542 + / - 5°c
Boiler design pressure – 16.6 mpa (g)
Feed water temperature – 248.6°c

BOILER PARAMETERS UNITS 100 % BMCR
BASE
RATED SH STEAM FLOW T/H 520
RATED SH STEAM PRESSURE MPa 14.5
RATED SH STEAM TEMPERATURE Deg.C 542
RATED RH STEAM FLOW T/H 425.8
RATED RH STEAM OUTLET PRESSURE MPa 2.95
RATED RH STEAM INLET PRESSURE MPa 3.087
RATED RH OUTLET TEMPERATURE Deg.C 542
RATED RH INLET TEMPERATURE Deg.C 335
DRUM WORKING PRESSURE MPa 15.86

BAGASSE
FEED WATER TEMPERATURE Deg.C 251
GCV Kcal/kg 2359
AMBIENT AIR TEMPERATURE Deg.C 35
COLD PA/SA AIR TEMPERATURE Deg.C 45
HOT PA AIR TEMPERATURE Deg.C 240
HOT SA AIR TEMPERATURE Deg.C 240
EXIST GAS TEMPERATURE Deg.C 145
BOILER GCV EFFICIENCY % 82.55
ATTEMPERATION WATER TEMPERATURE Deg.C 160

BAGASSE
FLUE & GAS FLOW AT APH OUTLET Nm3 / h 617302
PA FLOW AT APH INLET Nm3 / h 290645
SA FLOW AT APH INLET Nm3
/ h 226045
TOTAL ASH/SLAG FLOW Kg/h 39017
BOTTOM ASH FLOW Kg/h 8700
FLY ASH FLOW Kg/h 30317

COAL & ASH ANALYSIS UNITS PERFORMANCE
COAL - 2
TOTAL MOISTURE % 22.16
INHERENT % 7.85
VOLATILE MATTER % 22.02
FIXED CARBON % 28.33
ASH % 27.50
TOTAL % 100
GCV Kcal/Kg 3160.80

ULTIMATE ANALYSIS UNITS PERFORMANCE
COAL - 2
CARBON % 35.90
HYDROGEN % 2.39
OXYGEN % 10.55
NITROGEN % 1.23
SULPHUR % 0.27
ASH % 27.50
MOISTURE % 22.16
TOTAL % 100

HEATING SURFACE AREA:
Heated surface for Furnace m2 1825
Screen super heater area m2 1082
Wall tube at cyclone outlet m2 177
Upper HT Super heater m2 999
USH Additional Heating Area m2 83
Lower High temp.Economizer surface m2 1836
LSH Additional heating area m2 183
High temp.Economizer Surface m2 2161
HE Additional Heating Area m2 169
High Temp.Reheater Surface m2 2142
HR Additional heating area m2 128
Low Temp.Reheater Surface m2 5915

LR Additional Heating Area m2 565
Low Temp Economizer Surface m2 7519
Total Heating surface area (Pressure parts) m2 24784
Air Preheater Surface m2 27856

Velocity profile-Air & Flue gas Units
Fluidizingzone m/sec 4.5
Furnace m/sec 4
Cyclone I/L m/sec 22
Across hot super heater m/sec 10.7
Secondary/radiantsuper heater m/sec 5
Across cold super heater m/sec 9.2
Across cold Re- heater m/sec 12
Across hot Re- heater m/sec 10
Across Economizer-II (HT) m/sec 8.1
Across Economizer-I (LT) m/sec 8.9
Across air pre heater m/sec 8.8
ID FAN I/L & O/L Duct m/sec <15
PA fan Duct O/L m/sec <12

WATER VOLUME (HYDRAULIC TEST) UNITS
DRUM M3 34
WATER WALL SYSTEM M3 95
ECO M3 80
SUPER HEATER M3 60
TOTAL M3 269
REHEATER M3 188

GENERAL DESCRIPTION OF BOILER
Major
Components
of boiler
Pressure
Parts
Non
Pressure
Parts
Auxiliaries

PRESSURE PARTS
DRUM SCREEN COILS HP VALVES
WATER WALLS
SUPERHEATER / REHEATER ECONOMISER
NON PRESSURE PARTS
SUPPORTING
STRUCTURE
DUCTING J-SEAL
FUEL FIRING
SYSTEM
REFRACTORY CYCLONE
AUXILIARIES
PA/SA/ID FANS HP DOSING PUMP APH
SOOT
BLOWERS
J-SEAL BLOWERS COAL FEEDERS

BOILER PRESSURE PRTS:
Any closed vessel or container that contains pressure more than 1 Kg/cm2
called pressure part, pressure parts used for producing desire steam for
the turbine.
Pressure Parts: The following are the main pressure parts in the boiler
Economizer: Economizer preheat the feed water by absorbing heat from the
flue gas leaving from the boiler
a). Coal can be saved 15 to 20%
b). Increase the boiler thermal efficiency.
c). Increase the boiler life.
d).Decrease the thermal stresses of the internal parts.
e). Decrease in the combustion rate.

Super heaters: It increases the temperature of Main steam with the help of
temperature of flue gases to get Saturated Steam admitted to the HPT.
a). Super heat the steam in boiler before enter in t the turbine.
b). Removes the moisture contents from the steam to avoid the
corrosion and breaking of turbine blade tips.
Reheaters: It heats the temperature of steam outlet from HPT with the help
of Flue gas temperature.
a). Re-heats the steam to increase the thermal efficiency.
b). Increases the energy in the steam to perform additional work
before exhausting into condenser from LPT.

Water walls: Water walls carry feed water from ring headers to
Boiler Drum through raiser tubes, Acts as evaporator by absorbing
high temperature radiant heat by means of water cooled wall
construction.
Boiler Drum: It separates the steam from steam-water mixture and
produce produce water-free steam and steam-free water.
-It remove steam bubble from water volume entering down comer to
improve circulation
-Adding chemicals
- Facilitating blow down
De-Super heaters: It controls the main steam temperatures to safe
limit

PRESSURE PARTS MECHANICALDATA:
BOILER DRUM
Material SA-299 Gr A
Length in mm 1600
Inner dia in mm 1600
Thickness in mm 120
Cyclone separators no’s 64
Cyclone separator dia in mm 315
Steam flow for each cyclone t /h 7.81
Net Weight 100 MT Approx.

PRIMARY SCREEN SUPER HEATERS
Material SSA-213T22
Tube dia 42mm
Tube Thickness 7 mm
No of panels 6
Tubes in each panel 31
Pitch
SECONDARY SCREEN SUPER HEATERS
Material SA 213 -T91
Tube dia 42mm
Tube Thickness 7 mm
No of panels 6
Tubes in each panel 31
Pitch

HIGH TEMPERATURE SUPERHEATERS
Material SA 213 -T91
Tube dia 48mm
Tube Thickness 6mm
Pitch 110mm
REHEATER
Material SA- 210 A1,SA-213T12,
SA-213 T12,SA-213T91
Tube dia 60mm
Tube Thickness 4.5mm
Pitch 110mm
PLENUM
Material SA-210 A1
Tube dia 76mm
Tube Thickness 12mm
Pitch 160mm

LOWER ECONOMISER
Material SA -210 A1
Tube dia 51 mm
Tube Thickness 6 mm
Pitch 110 mm
UPPER ECONOMISER
Material SA -210 A1
Tube dia 51 mm
Tube Thickness 6 mm
Pitch 60 mm
WATER WALL PANNELS
Material SA -210 A1
Tube dia 60 mm
Tube Thickness 6.5 mm
Pitch 80 mm

PRESSURE PARTS MAINTENANCE SCHEDULE:
Description of Work Daily Monthly Quarterly Half
yearly
Yearly
1
PHYSICAL INSPECTION OF FURNACE AREA, SECOND
PASS AREA, PIPING AND FIXED POINTS (FROM OUT SIDE).
√
2
CHECK THE ALLIGNMENT OF THE BUCK-STAY
√
3 CHECK THE CONDITION OF SPRING HANGERS & PIPING
SUPPORTING SYSTEM. √
4 SURFACE CLEANING OF ALL TUBES (ECONOMISER,
WATER WALL TUBES, REHEATER, HIGH TEMPERATURE
SUPER HEATER) √
5 PHYSICAL CHECKING FOR EROSION OF TUBES,REPAIRE
IF REQUIRED. √
6 MEASURE THE TUBE THK[D-METERING& OD MEASURE]
AND RECORD. REPAIRE TUBES WHICH ARE 20%
ERODED. √
7 CHECHECK ALIGNMENT[PITCH,DIS-LOCATION] OF
TUBES, FIXING OF SPACER TUBES IF REQUIRED. √
8 PHYSICALLY INSPECT THE FIRST PASS WATER WALL
WELDING JOINTS, REPAIRE IF ANY DEFFECT. √
9 INSPECTION OF EROSION PROTECTION SHEILDS ,
REPLACEMENT OF THE SHEILDS IF REQUIRED. √
10 HYADRAULIC TEST OF THE BOILER (EXCLUDING
REHEATER) √
11 HYDRAULIC TEST OF THE BOILER INCLUDING REHEATER
√

PRESSURE PARTS TROUBLE SHOOTING:
BOILER FIRST PASS:
Trouble: Damage of metal spray on water wall tubes above the refractory zone,
Metal spray flakes may cause localized erosion on water wall tubes due to ash
passage through flake grooves.
Cause: Localized erosion by fluidized bed.
Action:
1. Leveling of metal spray flakes to the tube surface by grinding to facilitate easy
flow of circulating ash and avoid erosion of water wall tubes.
2. Metal spray at damage portion.

Trouble:Severe erosion on all the water wall tube joints in furnace area at
different elevations (18.5, 22.6 and 26.6 mtrs elevation).
Cause: Erosion by fluidized bed.
Action: Metal filling on eroded water wall joints.
BEFORE AFTER

Trouble: Water wall tubes erosion at boiler furnace corners, above the screen coils
area.
Cause: Due to the rough surface of refractory layer.
Action:
1. Metal filling on the damaged portion.
BEFORE AFTER

BOILER SECOND PASS:
Trouble: Misalignment (or) Dislocation of Erosion protection shields for
reheater hanger tubes, Economizer, Rehetaer and super heater coils.
Action:
1. Fixing and alignment of erosion protection shields at damaged area.
BEFORE AFTER

33
Corrosion
Over-
heating
Weld
Related
Hydrogen
Embrittle-
ment
Thermal
Softening
Cyclic
Fatigue
Mis-
applied
material
Erosion
Over-
stressing
TYPE
OF
FAILURES
BOILER TUBE FAILURES:

Erosion
• Visual Inspection-
– Thin edge failure. Pin hole leak
– The external surface appears
to be polished.
– Large loss of wall thickness
• Occurs in -
– Waterwall tubes
– Economizer tubes
– Superheater tubes.
Microstructure
– Normal ferrite plus pearlite
grain structure

Erosion
• Possible causes
– Coal/Ash content
– Local high flue gas velocities
– Improper setting of valves in blowers.
• Preventive measures to reduce failure
– Use of erosion resistance material (Inconel etc.)
– Shielding of Tube
– Gas / liquid flow velocity

• Visual Inspection
– Pin hole type rupture.
– Metal attack confined to surfaces
covered with soot deposits.(Small pits)
– Soot deposits evident on external
surface
• Occurs in
– Economizer tubes
– Furnace tubes
– Air-preheater tubes
• Microstructure
– Normal ferrite plus pearlite, sometimes
oxidation on grain boundaries seen
oint Corrosion
Dew point corrosion

Dew Point Corrosion
Possible causes Preventive Measures
Low back end Temperatures Feed water temperature above the
dew point
Low Feed water Temperatures Low Sulfur fuel
High Sulfur in fuel fired Reduce the no.of start & stop
Accumulation of sulfur rich deposits on
tubes for prolonged period ,during the
boiler idle time.
Use of cast grilled tube
Frequent cleaning of sulfur rich
deposits during shut down

Oxygen Pitting
– Pinhole initiated from ID surface in center of circular pit.
– Maybe pit has rusty appearance
• Occurs in -
– Waterwall tubes, Economizer tubes, Superheater tubes.
- Chances of pitting are more in horizontal tubes & at bends

Oxygen Pitting
• Microstructure
• Possible causes
– Water remaining in tubes during shutdown etc.
– Oxygen ingress / higher O2 in Feed water
Preventive Measures to reduce failures
– Strict adherence to the shut down & lay-up procedures
for protecting the tubes like maintaining alkaline pH,
keeping surface dry and clean
– regular sampling of tubes from specified zones for
metallurgical evaluation & internal deposit analysis
– regular wall thickness measurement at critical locations.
– Use of de-aerator (Mechanical / Chemical)

Fire side Corrosion
• Visual Inspection
– Longitudinal crack on
external surface may be
present.
– Large loss of wall thickness
– Thick hard/molten deposits
on external surface
• Occurs in -
– Waterwall tubes
– Superheater tubes
Microstructure
– Normal grain structure ,
sometimes grain boundary
oxidation may be seen

Fire side Corrosion
• Possible causes
– Aggressive coals containing high levels of chlorine
– Residual oils containing high levels of vanadium ,
sodium & sulfur.
• Preventive measures
– Preventive Measures to Reduce Failure
– Regular thickness measurement
– monitor temperature at suitable location

Overheating Failures
• Overheating failures
– Short Term:
– Long Term:
• Occurs in -
– Inbed evaporator tubes
– Common in Superheater tubes
– Furnace wall tube
– Convection banks

– Short Term:
• Longitudinal fish mouth opening
• Violent rupture, bulging may occur
• Rupture edges may be thin. No oxide scale on internal
& external surface.
– Long Term:
• Longitudinal fish mouth opening with thick lip fracture.
• Rupture may be with a bulge.
• Oxide scale evident on internal or external surface.
• Secondary cracks may be evident near the primary
rupture.

• Probable Causes -
– Tube starvation
– Flame impingement
– Upset in water chemistry
– Improper material
selection
– Steam bubble on
horizontal tubes,
Departure from Nucleate
Boiling (DNB) conditions
. Preventive Measures to Reduce
Failure overheating
– Avoid tube blockages by
cutting debris, weld spatter
– Proper coolant flow rates,
– Maintain drum-water levels
and control firing rates
– Modify Tube design with
internal ribbing or rifling
– Remove internal scale
– Upgrade metallurgy

WELD RELATED FAILURE
Common weld defects

Lack of Penetration Excess Penetration

Under cut Porosity

Incomplete Fusion Overlap

Under fill Excess Weld Reinforcement

Caustic Gauging
Visual Inspection
– Thin edge pin hole rupture.
– Excessive deposits & loss of
thickness on water side.
Occurs in -
– Waterwall tubes,
– Inbed tubes.
Microstructure
structure

Caustic Gauging
• Possible causes
– High levels of caustic in
boiler water
– Excess weld penetration
– DNB conditions, dirty boiler
ID surfaces & flame
impingement exacerbate the
problem .
Preventive measures to reduce
failure
– monitoring of heat flux using proper
thermocouples
– Stringent control on feed water
chemistry particularly on pH and
other Oxygen scavenger additions
– Regular sampling of tubes from high
heat flux zones for metallurgical &
internal deposit analysis
– Periodic inspection of proper burner
alignment
– Use of rifle tube

Hydrogen Damage
– Rupture in the form of window
type opening.
– Thick lip fracture.
– Fracture always brittle in nature.
– Excessive deposits on water side.
– Failure always on fire side.
– Sometimes thickness reduction is
seen.
• Occurs in -
– Waterwall tubes,
– Inbed tubes.
Microstructure
– Cracks along the grain boundaries
& sometimes decarburization
observed.

Hydrogen Damage
• Possible causes
– Upset in water Chemistry
– Dirty boiler ID surfaces
– Flame impingement may
exacerbate the problem.
Preventive measures to reduce failure
- Monitoring of heat flux using proper
thermocouples
- Stringent control on feed water chemistry
particularly on pH and other Oxygen scavenger
additions
- Regular sampling of tubes from high heat flux
zones for metallurgical & internal deposit
analysis and flattening test
- Periodic inspection of proper burner alignment
- In-situ hydrogen embrittlement analysis using
Ultrasonic methods
- Use of rifle tube

Dissimilar Metal weld ( DMW)
failure
– Usually, Circumferential
thick edge brittle failure
exactly at the interface
between the 2 tube weld.
• Occurs in -
– Superheater
– Reheater tubes

Stress Corrosion Cracking Fire side mechanical fatigue

Erosion Corrosion or Thermal Fatigue

Before starting any inspection, make sure that you should be equipped
with..
• Safety Dress ( Boiler suit, Helmet, Eye Goggle, Safety Shoes, Knee pad , Safety
Belt)
• A Power full torch
• A Scale and measuring Tape
• Demeter & Vernier
• A pen with small writing pad
• A marker and Chalk
• A Camera with proper holding arrangement
• Availability of drawing/relevant information of parts to be inspected
• Sufficient Illumination and proper scaffolding.
• Boiler isolated from other system
• At least one semi skilled labor for accompanying during inspection

BOILER DRUM
Drum is mounting equipment of boiler, the main function of the steam drum
is to separate the saturated steam and water by density difference.
The steam drum is made of material SA-299GrA, inner diameter is φ1600mm,
wall thickness is 120mm, drum length is 17750mm, and two ends use
spherical head.

Drum Internals:
Cyclone separator: The cyclone can remove the steam-
water mixture entering with high speed to keep water level
balance and to make primary separation for steam-water
mixture. The separated steam flow up-ward along the middle
part of cyclone, and the separated water flow down ward.
Corrugated plate separator: On the upper part of each
cyclone separator, there install a vertical corrugated plate
separator which further separate the water from steam by
equalizing the cyclone steam ascend velocity and working of
centrifugal force.
Orifice plate: The saturated steam separated by cyclone
pass through orifice plate and get washed by 50% feed water
from economizer, so that to reduce the steam salinity and
improve the steam quality.
Steam uniform distribution orifice plate: Depended on
the throating action of the multi-orifice plate, it can
uniformly distribute the steam to avoid steam excessive
centralization at some parts, it can also can stop the little
water drops.

Blow Down Pipe: Continuous blow down (CBD) pipe is located at
the upper part of the boiler water space, it drain out the water
containing highest salinity to keep the salinity of water with in
allowed range.
Dosing Pipe: The phosphate will be added through dosing pipe,
to keep the alkalinity of boiler water within allowed range.
Emergency Blow down Pipe: If the water level exceeds the
highest allowed level which caused by unmatched between boiler
feed water increasing and evaporation, it shall drain out the
water to normal level via EBD.

BOILER DRUM MAINTENANCE SCHEDULE
Description of Work Daily Monthly Half
yearly
Yearly 3 YEARS
1 PHYSICAL INSPECTION OF MAN HOLE DOORS,
MOUTINGS AND FITTINGS FOR ANY WATER OR
STEAM LEAKAGE. √
2
CHECK THE INTERNAL SURFACE OF DRUM FOR
PROTECTIVE MAGNETITE LAYER. √
3 INSPECT THE SURFACE OF DRUM FOR CARRYOVER
SYMPTOMS. √
4 IF CARRYOVER SIGNS ARE PRESENT THAT CHECK
THE BAFFLES (OR) INTERNALS THAT WERE
SUPPOSED TO BE SEAL WELDED. √
5 CHECK THE DRUM INTERNALS IS THERE ANY
PITTING , CORROSION (OR) CRACKINGS. √
6 CHECK AND CLEAN THE ANY SCALE (OR) SLUDGE
FORMATION ON THE PRIMARY SCRUBBER
ELEMENTS, FEED WATER LINE, CONTINEOUS BLOW
DOWN LINE, CHEMICAL FEED LINE. √
7 CHECK THE OPENINGS TO THE SAFETY VALVES
MUST BE FREE FROM THE OBSTRUCTIONS SUCH
AS MUD (OR) SCALE. √
8
HARD WARE TIGHTENING
√
9
MAN HOLE DOOR GASKETS REPLACEMENT.
√
10 REMOVAL OF ALL INTERNALS,INSPECTION AT
OUSIDE, CLEANING AND RE-FIXING. √

DESCRIPTION MATERIAL
SPECIFICATION
ELECTRODES FILLER WIRE
First pass water walls SA-210A1 E7018 ER70S-2
Primary screen
superehetaer
SA-213 T22 E9018-B3 ER90S-B3
Secondary screen
superhetaer
SA-213 T91 E9018-B9 ER 90S-B9
Water cooled plenum SA-210 A1 E7018 ER70S-2
Super heater SA-213 T91 E9018-B9 ER90S-B9
Reheater SA-213 T91 E9018-B9 ER 90S-B9
SA-213 T22 E9018-B3 ER 90S –B3
SA-213 T12 E8018-B2 ER 80S –B2
SA-210 A1 E7018 ER70S-2
2nd
Pass cage walls SA-210 A1 E7018 ER70S-2
SA-213 T12 E8018-B2 ER 80S-B2
Reheater hanger tubes SA-213 T12 E8018-B2 ER 80S-B2
Economizer Coils SA-210 A1 E7018 ER 70S-2
WELDING ELECTRODES FOR PRESSURE PARTS:

CHEMICAL REQUIREMENTS FOR FERITIC STEELS
GRADE CHEMICAL COMPOSITION %
C Mn Si S P Cr Mo V Ni Other elements
T11/P11 0.05-0.15 0.30-0.60 0.50-1.00 0.025 Max 0.025 Max 1.00-1.50 0.44-0.65 …… …… ……
T12/P12 0.05-0.15 0.30-0.61 0.50 Max 0.025 Max 0.025 Max 0.80-1.25 0.44-0.65 …… …… ……
T22/P22 0.05-0.15 0.30-0.60 0.50 Max 0.025 Max 0.025 Max 1.90-2.60 0.87-1.13 …… …… ……
T91/P91 0.08-0.12 0.30-0.60 0.20-0.50 0.010 Max 0.020 Max 8.00-9.50 0.85-1.05 0.18-0.25 ……
Nb= 0.06-0.10,
N=0.030-0.70,
Ni-0.40 Max,
Al=0.04 Max
TP304 0.08 Max 2.00 Max 0.75 Max 0.03 Max 0.40 Max 18.0-20.0 …… …… 8.00-11.0 ……
TP304L 0.035 Max 2.00 Max 0.75 Max 0.03 Max 0.04 Max 18.0-20.0 …… …… 8.00-13.0 ……
TP310S 0.08 Max 2.00 Max 0.75 Max 0.03 Max 0.045 Max 24.0-26.0 0.75 Max …… 19.0-22.0 ……
TP316 0.08 Max 2.00 Max 0.75 Max 0.03 Max 0.04 Max 16.0-18.0 2.00-3.00 …… 11.0-14.0 ……
TP316L 0.035 Max 2.00 Max 0.75 Max 0.03 Max 0.04 Max 16.0-18.0 2.00-3.00 …… 10.0-15.0 ……
PRESURE PARTS MATERIALS CHEMICAL COMPOSITION:

HP VALVES:
The common types of conventional HP valves used in the power plan are:
Gate valves
Globe valves
Check valves
Butterfly valves
ball valves
plug valves
The salient features and recommendations for usage of the above-mentioned
main valves are below:
Gate valves: These valves are the simplest in design & operation and most
widely used. These types of valves operate with minimum turbulence within the
valve and has a very low-pressure drop. Gate valves are normally used for
throttling service.

Globe valves: Globe valves are normally used where the operation is frequent
and/or primarily in the throttling service to control flow to any desired degree.
Since the valve seat is parallel to the line of flow , globe valves are recommended
where resistance to flow and pressure drop are permitted because of design of
the valve body is such that it changes the direction of flow causing turbulence and
pressure drop within the valve. Globe valves have the highest-pressure drop of
any of the more commonly used valve

Check valves: These valves are designed to prevent reverse flow (which allows flow
only one direction) in a piping system. Swing check valves are commonly used in piping
system. These valves allow unobstructed flow, opening with line flow and closing
automatically with the decries in pressure. The check valve with a hinged arm and disc
which swings like a door. The hinge pin can be mounted either internally or externally.

ISSUE PROBABLE CAUSE SOLUTION
Leakage
through the
stem packing
a) Gland nuts are loose.
b) Gland is binding against the
stem or packing chamber
wall.
c) Inadequate amount of
packing rings
d) Packing is hard and dry
e) Packing was not properly cut
and staggered.
f) Stem is damaged
a) Tighten gland nuts.
b) Ensure gland is centered and
evenly tightened
c) Install additional packing
rings.
d) Replace with new packing ring
e) Replace with new packing
ring.
f) Repair or replace as required.
Problems while
operating the
valve
a) Stem binding during travel
b) Packing is exerting excessive
force on the stem
c) Stem is damaged.
d) Internal compounds may be
damaged.
a) Remove dirt and lubricate
stem
b) Optimize the torque on gland
nuts.
c) Examine stem through full
open and close action. Repair
or replace as required.
d) Disassemble the valve. Inspect
GENERAL TROUBLE SHOOTING:

ISSUE PROBABLE CAUSE SOLUTION
Seat Leakage a) Valve is not properly seated
b) Internal components are
damaged or have worn out.
a) Check whether the valve is
tightly closed.
b) Disassemble the valve and
inspect internal components.

HP VALVES MAINTENANCE SCHEDULE
Description of Work Daily Half
yearly
Yearly 2 Years 4 Years
PHYSICAL INSPECTION OF VALVES FOR ANY WATER (OR)
STEAM LEAKAGE FROM BONNET OR FROM GLANDS.
√
SAFETY VALVES[DRUM,MS&RE-HEAT]
SERVICING OF SAFETY VALVES WORK INCLUDES
INSPECTION OF VALVE INTERNALS LIKE DISC, NOZZLE RING,
GUIDE RING, SEAT, SPRING, STEM.REPLACEMENT OF
DAMAGED PARTS. √
HAND POPING OF SAFETY VALVES
√
SAFETY VALVES FLOATING (PRESSURESETTING &
BLOWDOWN SETTING) √
INSPECTION OF SILENCERS
√
OVERHAUL OF VALVES
√
EMRV&PILOT VALVE
PHYSICAL INSPECTION OF VALVES FOR ANY STEAM
LEAKAGE FROM BONNET/FLANGES.
√
SERVICING: INTERNALS INSPECTION OF PILOT VALVES &
MAIN VALVE i.e. DISC, STEM, SEAT, SPRING, GASKETS,
SEAL RINGS. √
INSPECTION OF SILENCERS
√

Description of Work Daily Half
yearly
Yearly 2 Years 4 Years
START-UP VENT VALVES
LEAKAGE FROM BONNET/FLANGES/GLANDS.
√
SERVICING OF START-UP VENT VALVES WORK INCLUDES
INSPECTION OF VALVE INTERNALS LIKE STEM,
DISK,GLANDS, GASKETS,PRESSURE SEAL RINGS. √
OVERHAUL OF VALVES √
BLOCKED VALVES
LEAKAGE FROM BONNET/FLANGES.
√
SERVICING OF BLOCKED VALVES
√
REPLACEMENT OF GRAPHITE SEAL RINGS.
√
BLOWDOWN VALVES
LEAKAGE FROM BONNET/FLANGES/GLANDS.
√
SERVICING OF BLOWDOWN VALVES WORK INCLUDES
INSPECTION OF VALVE INTERNALS LIKE STEM,
DISK,GLANDS, PRESSURESEAL RINGS.
√

CONTROL VALVES
LEAKAGE FROM BONNET/FLANGES/GLANDSAND ANY AIR
LEAKAGE FROM ACTUATOR,INSTRUMENTS AND PIPING.
√
SERVICING OF CONTROL VALVES WORK INCLUDES
INSPECTION OF VALVE INTERNALS LIKE CAGE, STEM,
GLANDS, GASKETS, TRIM √
OVERHAUL OF VALVES.
√
STOP VALVES
LEAKAGE FROM BONNET/GLANDS.
√
STOP VALVES LIMIT SETTING (OPEN / CLOSING)
√
SERVICING OF STOP VALVE WORK INCLUDES INSPECTION
OF VALVE INTERNALS LIKE STEM, DISK,GLANDS,
GASKETS, PRESSURESEAL RINGS.REPLACEMENT OF
DAMAGED PARTS √
OVERHAUL OF VALVES. √

SAFETY VALVES :
1. Introduction:
A valve which automatically, without the assistance of any energy other
than that of the fluid concerned, discharges a quantity of the fluid so as
to prevent a predetermined safe pressure being exceeded, and which is
designed to re-close and prevent further flow of fluid after normal
pressure conditions of service have been restored.
Safety valves should be installed wherever the maximum allowable
working pressure (MAWP) of a system or pressure-containing vessel is
likely to be exceeded. In steam systems, safety valves are typically used
for boiler overpressure protection and other applications such as
downstream of pressure reducing controls. Although their primary role is
for safety, safety valves are also used in process operations to prevent
product damage due to excess pressure.

1.Safety Valve Components:
Safety Valve Components:

DEFINITION OF TERMS
Set Pressure:
This is the pressure at which the valve begins to lift from the valve
seat, otherwise known as the simmer point since the sound of
escaping steam is quite audible.
This pressure is set sufficiently above the normal working pressure
of the boiler in order to avoid unnecessary simmering such as might
be induced by normal fluctuations in steam pressure when on load.
Closing Pressure:
Closing pressure is the pressure at which the valve reseats.
Blowdown
The blowdown is the difference between the set pressure and the
closing pressure expressed as a percentage of the set pressure e.g.
Blowdown % = Set pressure-Closing pressure x100
Set pressure

SAFETY VALVES SETTING:
This operation involves increasing and decreasing heat input to the
boiler, to raise and lower the steam pressure. The set pressure and
closing pressure of each valve is checked and adjust in turn from the
highest-pressure valve first to the lowest pressure last.
There are two stages of safety valves floating in our regular practice:
a). Drum & M.S Safety valves floating.
b). CRH & HRH Safety valves floating.
Drum & M.S Safety valves floating Procedure:
1. For testing of drum left side safety valve ensure the following
a) EMRV & Start up vents valves are in healthy operation condition.
b) Keep open the M.S start-up vent valves by 5% at all the time, till
the completion of safety valve floating activity.
2. Boiler Lighted Up, Gradually Increase firing rate through Burners and
at the same time, by regulating HP & LP bypass system and raise the
boiler pressure.

2. Gag the drum left side, M.S safety valves at 85% of respective
valves set pressures.
3. Raise the system pressure to 174.5 KG/CM2 by increasing firing
in boiler.
4. If it float’s before set pressure, reduce firing rate, then by reduce
pressure 15% less to the popping pressure.
5. Tighten check nut, it gives more load on spring, thereby on stem.
6. Set the valve popping pressure by adjusting load on stem @ 174.5
KG/CM2.
7. Next set the blowdown %.
8. Note down the popping pressure and reset pressure.
9. If it reaches within 4-7% blowdown, it is ok.
10.If blowdown % less than 4%, adjust guide ring, lower the ring to
down by adjusting the screw to clock wise direction.
11.If blowdown % more than 7% adjust guide ring to up-ward
direction by adjusting the screw to anti-clock wise direction.
2. If it is not coming around 4-7% with number of trails, then try
with nozzle ring.
a) Raising the nozzle ring will increases blowdown.
b) Lowering the nozzle ring will decreases blowdown.

2. After completing the pressure setting of all valves, all the gags of
the safety valve are removed and kept safely for any future use.
3. The other safety valves in M.S Header & Drum safety valves floated
on similar lines as explained above.

PRESSURE PARTS TUBE SPARES TO BE MANTAINED
DESCRIPTION
MATERIAL
SPECIFICATION
SIZE
SPARETO BE
MAINTAINED(Mtrs)
1ST
PASS WATER WALL PANELS
(Front,Rear,Left&Right) & WATER COOLED
SCREEN
SA-210 A1 Φ 60X6.5 100
Primary Screen Super Heater Coils SA-213 T22 Φ 42x7 100
Secondary Screen Super Heater Coils SA-213 T91 Φ 42x7 100
Water Cooled Plenum SA-210 A1 Φ 76x10 100
Super Heater System Coils SA-213 T91 Φ 48x6 100
Reheaters System Coils
SA-213 T91
Φ 60x4.5
100
SA-213 T22 100
SA-213 T12 100
SA-210 A1 100
Front Cage Water Wall Panel
SA-213 T12
Φ 45x5.5
100
SA-210 A1 100
Rear & Side Cage Water Wall
SA-213 T12
Φ 51x6
100
SA-210 A1 100
Middle Baffle Cage Wall
SA-213 T12
Φ 51x10
100
SA-210 A1 100
Reheater Hanger Tubes SA-213 T12 Φ 45x8 100
Economiser Coils SA-210 A1 Φ 51x6 100

PRESSURE PART BENDS STOCK TO BE MANTAINED
BEND DESCRIPTION SIZE RADIUS MATERIAL QTY (NO’S)
90 Deg. Elbow for ECO-1 51x6 R 76 SA-210A1 50
180 Deg. Elbow for ECO-1 51x6 R 51 SA-210 A1 50
90 Deg. Elbow for HTSS 48x6 R 110 SA-213 T91 50
180 Deg. Elbow for HTSS 48x7 R 55 SA-213 T91 50
90 Deg. Elbow for RH 60x4.5 R 85 SA-213 T91 50
90 Deg. Elbow for RH 60x4.5 R 85 SA-210 A1 50
180 Deg. Elbow for RH 60x4.5 R 55 SA-210 A1 50

Control valve spares
Valve Description Make Spare Description Qty (No's)
CBD Control Valve - DN20, PN32 Herbin Stem 1
Motor Operated CBD Valve - DN20 Herbin Stem 1
M.S.Start-upvent Back-washer - DN50 Herbin Packing 2
Emergency Blow-Down Valve - DN50 Herbin
Disc 1
Stem 1
Packing 2
M.S.Start-Up Vent Valve - DN100 Herbin
Disc 1
Press Ring 1
HRH Start-Up Vent Valve - DN100 Herbin
Disc 1
Packing Ring 2
EMRV - DN65 Herbin
Main Disc 1
Packing Ring 3
Gasket 1
Disc 1
Seat 1
Gasket 3
Stem 1
Electromagnet 2
Spring 1
HRH Safety Valve - DN200 Herbin
Lower Adjusting Ring 1
Upper Adjusting Ring 1
Thermal Disc 1
Spring 1
Stem 1
CRH Safety Valve - DN152 Herbin
Thermal Disc 1
Spring 1

Drum Safety Valve - DN90 Herbin
Thermal Disc 1
Stem 1
Spring 1
M.S Safety Valve - DN60 Herbin
Disc Assembly 1
Spring 1
Stem 1
Feed Water Control station- Motor operated
Gate Valve - DN175
Herbin
Gasket 2
Left Disc 1
Right Disc 1
Stem 1
Seal Ring 1
Motor Device 1
Feed Water Control station- Motor operated
Gate Valve - DN250
Herbin
Gasket 2
Right Disc 1
Left Disc 1
Seal Ring 1
Motor Device 1
Stem 2
M.S.Stop Valve - DN250 Herbin
Right Disc 2
Left Disc 2
Seal Ring 1
Packing 10
Motor Device 1
Stem 1
Economizer StopValve - DN50 Herbin
Disc 2
Stem 2
Packing Washer 2
Packing 5
Packing Gland 3

DN32 Globe Valve Herbin
Disc 2
Packing 10
Stem 2
DN10 Globe Valve Herbin
Disc 1
Packing 10
Full Nitrogen of Re-heater - DN20 Herbin
Disc 3
Plug 3
Full Nitrogen of Super Heater - DN20 Herbin
Disc 3
Plug 3
Check Valve - DN50, PN32 Herbin
Disc 3
Spring 3
Feed Water Control station - Check Valve -
DN250
Herbin
Disc 1
Seal Ring 2
Check Valve for Attemperation Herbin
Spring 2
Packing 4
Disc 2
DN20 Motor-operated Drain Valves Herbin
Disc 3
Packing 10
DN65 Gate valve Herbin
Disc 1
Stem 1
Packing Ring 2
DN20 Control Valve Herbin
Packing Ring 2
Packing 2
Atretic Valve for Superheater Attemperation -
DN50
Herbin
Disc 1
Stem 1
Pnuematic Actuator 1

Feed Control Station Control Valve - 6" X 4" Herbin
Cage 1
Plug 1
Stem 1
Balance Seal 10
Seat Gasket 5
P/B Gasket 6
Bonnet Gasket 5
Packing Seat 3
Gland Packing 10
Feed Control Station Control Valve - 6" X 3" Herbin
Cage 1
Plug 1
Stem 1
Balance Seal 5
Seat Gasket 5
P/B Gasket 5
Bonnet Gasket 5
Packing Seat 2
Gland Packing 5
Primary attemperation station control valve -
2" X 1"
Herbin
Plug 2
Bonnet Gasket 5
Gland Packing 10
Packing Seat 5
Seat Gasket 5
Secondry super heater attemperation control
valve - 1/2" X 3/8"
Herbin
Plug 2
Bonnet Gasket 5
Gland Packing 10
Packing Seat 5
Seat Gasket 5
Reheater attemperation controlvalve - 1" X
3/8"
Herbin
Plug 2
Bonnet Gasket 5
Gland Packing 10
Packing Seat 5
Seat Gasket 5

VALVE SPARES
VALVE SPARES- HERBIN MAKE
Valve Description Spare Description Qty (No's)
CBD Control Valve - DN20, PN32 Stem 1
Motor Operated CBD Valve - DN20 Stem 1
M.S.Start-up vent Back-washer - DN50 Packing 2
Emergency Blow-Down Valve - DN50
Disc 1
Stem 1
Packing 2
M.S.Start-Up Vent Valve - DN100
Disc 1
Press Ring 1
HRH Start-Up Vent Valve - DN100
Disc 1
Packing Ring 2
EMRV - DN65
Main Disc 1
Packing Ring 3
Gasket 1
Disc 1
Seat 1
Gasket 3
Stem 1
Electromagnet 2
Spring 1
HRH Safety Valve - DN200
Thermal Disc 1
Spring 1

CRH Safety Valve - DN152
Thermal Disc 1
Spring 1
Stem 1
Drum Safety Valve - DN90
Thermal Disc 1
Stem 1
Spring 1
M.S Safety Valve - DN60
Disc Assembly 1
Spring 1
Stem 1
Feed Water Control station - Motor operated Gate Valve - DN175
Gasket 2
Left Disc 1
Right Disc 1
Stem 1
Seal Ring 1
Motor Device 1
Feed Water Control station - Motor operated Gate Valve - DN250
Gasket 2
Right Disc 1
Left Disc 1
Seal Ring 1
Motor Device 1
Stem 2
M.S.Stop Valve - DN250
Right Disc 2
Left Disc 2
Seal Ring 1
Packing 10
Motor Device 1
Stem 1

Economizer StopValve - DN50
Disc 2
Stem 2
Packing Washer 2
Packing 5
Packing Gland 3
DN32 Globe Valve
Disc 2
Packing 10
Stem 2
DN10 Globe Valve
Disc 1
Packing 10
Full Nitrogen of Re-heater - DN20
Disc 3
Plug 3
Full Nitrogen of Super Heater - DN20
Disc 3
Plug 3
Check Valve - DN50, PN32
Disc 3
Spring 3
Feed Water Control station - Check Valve - DN250
Disc 1
Seal Ring 2
Check Valve for Attemperation
Spring 2
Packing 4
Disc 2
DN20 Motor-operated Drain Valves
Disc 3
Packing 10
DN65 Gate Valve
Disc 1
Stem 1
Packing Ring 2
DN20 Control Valve
Packing Ring 2
Packing 2
Atretic Valve for Super heater Attemperation - DN50
Disc 1
Stem 1
Pneumatic Actuator 1

VALVE SPARES- KOSO MAKE
Valve Description Spare Description Qty
Feed Control Station Control Valve - 6" X 4"
Cage 1
Plug 1
Stem 1
Balance Seal 10
Seat Gasket 5
P/B Gasket 6
Bonnet Gasket 5
Packing Seat 3
Gland Packing 10
Feed Control Station Control Valve - 6" X 3"
Cage 1
Plug 1
Stem 1
Balance Seal 5
Seat Gasket 5
P/B Gasket 5
Bonnet Gasket 5
Packing Seat 2
Gland Packing 5

VALVE SPARES- KOSO MAKE
Valve Description Spare Description Qty
Primary attemperation station control valve - 2" X 1"
Plug 2
Bonnet Gasket 5
Gland Packing 10
Packing Seat 5
Seat Gasket 5
Secondary super heater attemperation control valve - 1/2"
X 3/8"
Plug 2
Bonnet Gasket 5
Gland Packing 10
Packing Seat 5
Seat Gasket 5
Reheater attemperation control valve - 1" X 3/8"
Plug 2
Bonnet Gasket 5
Gland Packing 10
Packing Seat 5
Seat Gasket 5

PRIMARY AIR CIRCUIT
APH
FURNACE
C
C
F
1
C
C
F
2
C
C
F
3
C
C
F
4
C
C
F
5
C
C
F
6
PA A PA B
COLD AIR LINE
HOT AIR LINE 240
Deg.C
SEAL AIR LINE
COAL SPOUT AIR
LINE
APH BY PASS

PRIMARY AIR CIRCUIT
 The air coming from Pa fan is named as Primary
air
 Primary air is using for combustion the fuel.
 An atmospheric air is heated about 240 deg. C by
indirect heat transfer from the flue gas in APH and
again forced to HGG.
 The positive draft is maintained by PA fans
 The maximum flow in the primary circuit is
4,00,000 cub m /hr.

SECONDARY AIR CIRCUIT
APH
SA A SA B
FURNACE
COLD AIR LINE
HOT AIR LINE 240 Deg. C
ABOVE BED
BURNERS
APH BY PASS
SECONDARY
AIR
SECONDARY
AIR
SECONDARY
AIR BOX
ABOVE BED
BURNERS
TERTIARY
AIR

SECONDARY AIR CIRCUIT
 The air coming from Sa fan is named as
Secondary air
 Secondary air is using for control the combustion
in combustion chamber (furnace).
 An atmospheric air is heated about 240 deg. C by
indirect heat transfer from the flue gas in APH and
again forced to secondary & teritiary air.
 The positive draft is maintained by SA fans
 The maximum flow in the secondary circuit is
2,00,000 cub m /hr.

FLUE GAS PATH
J seal air
SH
RH
ECO2
ECO 1
APH
PRIMARY AIR
TO ESP

AIR PRE -HEATER
HEATING SURFACE AREA : 27856 sq. m
SIZE OF TUBE : Dia 51 X 3 mm
PURPOSE
 Air preheater is an auxiliaryequipment for steam
generators.
 It is a heat exchangerthat absorbs waste heat from exit flue
gas in boiler and transfers the heat to the coldair to achieve
maximum boiler thermalefficiency
LOCATION OF APH
 Located in 2 nd pass of boiler after economizerin the flue
gas path
 It is the last heat recovery equipment in the boiler

AIR PRE-HEATER
BASIC FUNCTION OF APH
An air pre-heaterheats the combustion air where it is economically
feasible.
The pre-heating helps the following.
1. Igniting the fuel.
2. Improving the combustion.
3. Drying the pulverizedcoalin pulverizer
4. Reducing the stack gas temperature and increasing the boiler
efficiency.
5. In utility and processboilers APH is usedto heat the air
requiredfor combustion purpose and to dry and transport the
coal

AIR PRE -HEATER
TYPES OF APH
Classification of APH according to operating principle. These may be
arranged so the gas flows horizontally or vertically across the axis of
rotation
1. Recuperative Heaters
Tubular Air Pre-Heaters
Plate Air Pre-Heaters
2. Regenerative Heaters

AIR PRE-HEATER
Recuperative Heaters operating principle
 Transfers the heat across flow direction through the separating partition of
either plates or tubes with the cold sidecontinuously recuperating
(absorbing) the heat conducted from the hot side
 Separating surfaces may be composed of steel tubeor plates.
 Mixing of air and flue gas is not possible during normal operation except in
case of leakage of tubes
Regenerative Heaters operating principle
 It is the indirect heating type APH. Rotating heavystructure
servesas an intermediate heat storagesurface.
 Cold surface convertedinto heatedsurface when exposedin
the passage of hot flue gas. This heated surfaceis then
brought in contact with coldair to give the heat.
 Heat energyis again regeneratedin the structure.

CONSTRUCTION FEATURES
Tubular preheaters consist of straight tube bundles which
are kept in the boilerflue gas path. The hot furnace gas passes
around the air preheatertubes, transferring heat from the exhaust
gas to the air inside the preheater.
Ambient air is forcedby a fan throughducting at one end
of the preheater tubes and at otherend the heatedair from inside
of the tubes emerges into another set of ducting, whichcarries it
to the boiler furnace for combustion.

AIR PRE-HEATER
APH OPERATING PARAMETERS

AIR PRE-HEATER
Tubular Air Pre-Heaters
 It consist of a series of long horizontal straight tubes of 52 mm
diameter and 2 mm thick weldedinto the tube
plates(perforated) at the bothends and enclosing casing
providedwith inlet & outletopeningsfor cold and hot air.
 Cold air is flowing inside the tubes and flue gas is flowing over
the tubes and passing heat to the cold air
 In betweenthe inner joining ducts, baffle platesare providedto
the directair over the entire surface of the tubes in cross-flow
direction.

AIR PRE-HEATER
Advantages of Tubular Air Pre-Heaters
 It is also quite suitable for High pressure air sides also , as in case of
rotary type only suitable for low pressures.
 Maintenance involved is less and easy as absence of moving parts.
Hence maintenance cost is reduced.
 Tubular Air Pre-Heaters having long life thanregenerative type.
 Lowinitial cost.
 No auxiliary consumption as absence of moving parts
 Easily can attend in trouble shootings.
 No possibility of fly ash carry over by the heated primary and
secondary air
 It occupies low space compared with regenerative type. Regenerative
APH having

APH PERFORMANCE
Boilerefficiency decreases generallyan account of APH
performancedegradation. This also effects ESP,ID&FD fan
loadings.
EACTORSAFFECTING APH PERFORMANCE
 EXCESSAIR LEVEL
 Primaryair to Secondaryair ratio
 Moisture in coal
 Procedure for cleaning. Soot blowing & regular maintenance.
 Optimum flue gas temperature is requiredfor effective ESP
performance

APH PERFORMANCE TEST
For better performanceof APH following test should be conducted
1.APHAIR LEAK TEST
PROCEDUREFOR APH AIR LEAK TEST DURINGSHUT DOWN
 ENSUREALL BOILER PA/SA FANSOFF CONDITION.
 KEEP OPEN FURNACEMANHOLE DOORS
 KEEP CLOSEALL MANHOLE DOORS OF ESP AND APH[FLUE GAS
SIDE].
 CLOSEPA SUCTION DAMPERS[2NO’S].
 CLOSEPA DISCHARGEDAMPERS[2NO’S].
 CLOSEPA BY-PASSDAMPERS[2NO’S].

APH AIR LEAK TEST
 CLOSE PA SEAL AIR DAMPERS [1NO’S].
 CLOSE SA SUCTION DAMPERS [2NO’S].
 CLOSE SA DISCHARGE DAMPERS [2NO’S]
 CLOSE SA BY-PASS DAMPERS [2NO’S]
 ENSURE RE-HEATER DAMPERS OPEN POSITION.
 ENSURE ECONOMISER DAMPER OPEN POSITION.
 ENTER PA/SA MODULE [BOTH SIDES] BY OPENING AIR SIDE
MANHOLE DOORS
 TAKE ID FAN IN TO SERVICE AND KEEP FLUE GAS PRESS -200MMWC
AT ESP INLET
 CHECK FOR AIR LEAKAGE AT PA MODULE [HISSING NOISE WILL
COME INCASE OF AIR LEAK].
 CHECK FOR AIR LEAKAGE AT SA MODULE [HISSING NOISE WILL
COME INCASE OF AIR LEAK].
 PROVIDE DUMMIES FOR LEAKING TUBES OF SA AND PA MODULES

DESIGN PARAMETERS
Total Flow Pressure (mmwc) Temperature (oc )
Primary Cold Air 4,00,000
cub m/ hr.
1950 30oc
Primary Hot Air 4,00,000
cub m/ hr.
1950 240oc
Secondary Cold Air 4,00,000
cub m/ hr.
1300 30oc
Secondary Hot Air 4,00,000
cub m/ hr.
1300 24oc
Flue gas at ID fan inlet 6,54561
cub m/ hr.
-652 144.3oc
High Pressure Fluid Air
(J Seal Air)
15000 cub
m/ hr.
5000 70oc

DESIGN PARAMETERS OF AIR & FLUE GAS
Area Medium Pressure
(mmwc)
Temperature (oc )
Plenum or Wind Box Air 2000 1000
Furnace Lower Combustion Chamber Flue Gas 1500 1200
Furnace Middle Combustion
Chamber
Flue Gas 900 1200
Furnace Upper Combustion Chamber Flue Gas 500 1200
Furnace Out let Flue Gas 250 1200
Loop Seal Flue Gas -250 1200
Re heater Inlet Flue Gas -250 1000
High Temperature Super Heater Inlet Flue Gas -250 1000

DESIGN PARAMETERS OF AIR & FLUE GAS
Area Medium Pressure
(mmwc)
Temperature (oc )
Middle of Re heater Flue Gas -300 800
Inlet of High Temperature Economizer Flue Gas -300 800
Re heater Outlet Flue Gas -350 500
Outlet of High Temperature
Economizer
Flue Gas -350 500
Mid Flue of Low Temperature
Economizer
Flue Gas -400 500
Outlet of Low Temperature Economizer Flue Gas -450 400
Mid Flue of Air Pre-Heater Flue Gas -480 400
outlet Flue of Air Pre-Heater Flue Gas -570 300

MAINTENANCE SCHEDULES
DESCRIPTION DAILY WEEKLY MONTHLY HALF -
YEARLY
YEARLY
PHYSICAL INSPECTION OF APH, DUCTS
AND DAMPERS FOR ANY AIR (OR) GAS
LEAKAGES.
√
AIR CLEANING OF APH TUBES √
CONDUCTING AIR LEAK TEST FOR PA &
SA MODULES FOR FIND OUT AIR
LEAKS.
√
CHECK FOR ANY AIR LEAKAGES AT
FLANGES, GLANDS
√
CHECK FOR ANY BOLTS LOOSEN OF
ALL MANUAL DOORS & FLANGES
√

MAINTENANCE SCHEDULES
DESCRIPTION DAILY WEEKLY MONTHLY HALF -
YEARLY
YEARLY
CHECK FOR EXPANSION BELLOWS,
REPLACE IF ANY DAMAGE
√
CHANGING OF GLAND ROPES
√
CHANGING OF OILS IN GEAR
BOXES FOR GUILLOTINE
DAMPERS
√
APPLYING LUBRICATION FOR
PLUMBER BLOCKS OF
GUILLOTINE DAMPERS
√
APPLYING LUBRICANT FOR
DAMPER GLANDS
√

ISOLATION TYPES
 MULTI LOWER FLIP DAMPERS
 BUTTER FLY DAMPERS
 SINGLE STRAP ISOLATION GATES
 GUILLOTINE DAMPERS

MULTI LOWER FLIP DAMPERS
MAKE: BACHMANN
INDUSTRUIS,
TYPE : FLIP TYPE
DUTY: CONTROL, INCHING
 These are pneumatic
operatedvalves.
 Used at seal air & coal
spout air line for furnace
chutes
 Total24 no’s valves

BUTTERFLY DAMPERS
MAKE: BACHMANN INDUSTRUIS
TYPE : DOUBLEFLIP
DUTY: CONTROL, INCHING.
 These are manual & pneumatic cylinder operated valves.
 Usedat primary & secondary air circuits
 Total 24 no’s valves
 BothRectangle & roundshapes in construction

SINGLE STRAP ISOLATION GATES
MAKE: BACHMANN
INDUSTRUIS
TYPE : SINGLEFLIP
DUTY: ON-OFF.
 These are manual
operated valves.
 Used at secondary &
tertiary air lanes
 Total 28 no’s valves

GUILLOTINE DAMPERS
MAKE: FORESSINDUSTRIES
TYPE : GLANDULARBLADE
DUTY: ON-OFF
 These gateshaving 99%
seal efficiency
 Having 7 no’s in flue gas
pathafterAPH
 2 for ESP inlet, 3 for ID fan
inlet & 2 for ID fan outlet

NON-METALLIC EXPANSION BELLOWS

Boiler fans
Prepared by
DNV.Ravi Shankar
Checked and approved by
B.Ramarao

General arrangement of Centrifugal fan 150MW-PP PALONCHA

BOILER FANS
INTRODUCTION
 The main purpose of the fans in the Boiler is supply
AIR to complete the combustion of fuel and to
maintain the DRAUGHT in the furnace.
TYPES
 There are two primary types of FANS
 Centrifugal fans
 Axial fans.

Working principle
 Centrifugal Fans are most commonly type
of used in Boilers. Centrifugal fan use a
rotating impeller to increase the velocity
of fan air stream. As the air moves from
impeller hub to fan blade, it gains the
kinetic energy. This kinetic energy then
converted to static pressure increase as
the air slows before entering in to the
discharge.

Types of centrifugal fans
 Centrifugal fans are capable of generating high volume of air
with higher effeciencies.Centrifugal fans have several types of
blade types.
 Forward curved type
 Radial Blade type
 Backward inclined type
 Backward curved type
 Backward curved airfoil type

System description:
 Nava Bharat Energy India Limited is a 1 X 150MW
Thermal Power Plant which Air is the main source of
boiler for combustion of fuel and maintaining the
draught.
 The main sources of supplying Air to the boiler are
Primary air and secondary air.
 By removing flue gasses in the furnace for entering fresh
air Induced draught fan (ID) is used.
 Two nos of PA fans are used for supplying primary Air
which are having the fallowing technical specifications.

Technical specification
PA FAN 2 NOS:-
FAN MAKE ANDREW YULE
TYPE OF FAN
SINGLE INLET
BACKWORD
AEROFOIL BLADE
FLOW OF FAN (MCR) M3/Hr 212977
STATIC PRESSURE INLET mmWG -11.5
PRESSURE OF OUTLET mmWG 1950
OPTIMUM TEMP. 0C 35
SPEED OF FAN RPM 1440
DENSITY OF AIR KG/M3 1.1142
TYPE OF BEARING
DOUBLE ROLLER
SPHERICAL BEARING
BEARING LUBRICATING OIL ISO. VG 46
BEARING TEMP. 0C 70
FAN SIDE COUPLING & MAKE SPACER & UNIQUE
80-550-
300

Technical specification
SA FAN 2 NOS :-
TYPE OF FAN
SINGLE INLET BACKWORD
AEROFOIL BLADE
STATIC PRESSURE INLET mmWG -12
OPTIMUM TEMP. 0C 35
BEARING MAKE FAG
TYPE OF BEARING
DOUBLE ROLLER
SPHERICAL BEARING
BEARING TEMP. 0C 70
FAN SIDE COUPLING & MAKE RESILIENT & GBM 121 UP

Technical specifications
ID FAN 2 nos:-
TYPE OF FAN
DOUBLE INLET
BACKWORD CURVED
BLADE
STATIC PRESSURE INLET mmWG -652
OPTIMUM TEMP. 0C 144.3
TYPE OF BEARING
DOUBLE ROLLER
SPHERICAL BEARING
BEARING TEMP. 0C 70
FAN SIDE COUPLING & MAKE SPACER & UNIQUE
80-700-325121
UP

STARTING UP
The fallowing points shall be checked before and
during the initial run up of a fan to operating speed on
all installation.
VOITH SIDE
 Check and ensure all foundation bolts tightness.
 Alignment between Voith couplings by keeping
down i.e., offset values on both sides of Motor
and driven machines including DBSE gaps.

 Inspection of oil pipe lines & pickling of same ( Voith hydraulic
coupling to cooler inlet & cooler outlet to Voith hydraulic
coupling inlet) Cooling water line connections & flushing of
same.
 Connecting of Voith hydraulic coupling interlocks to control
room & pneumatic connection to actuator.
 Oil filling in Voith hydraulic coupling (For ID,PA&SA fan
couplings SERVO SYSTEM HLP 32 .
 Main connections to Motor & Completion of Motor solo trail
run.
 Actuator Wiring completion and connections to DCS.

FAN SIDE
 During the first run of the fan check the oil levels in bearing
housings.
 Ensure all cooling water circulation lines are in open position.
 Before starting the fan check and clean the scrap material
inside the impeller casing.
 During the first run, the installation shall be checked for any
sign of undue vibration and if this is present the fan shall
stopped immediately and the cause investigated.

 Check the Inspection doors and casing joints are fully bolted
up or not.
 Check that the bearing housings are filled to the correct level
with recommended oil.
 Check the proper operation of inlet and discharge dampers
and actuator operation too.
 Ensure “Alarm” and “Trip” signals are properly set
for Fan and motor.
 Ensure proper function of “Emergency of” switch

MAINTENANCE OF THE FAN
Daily maintenance.
 For smooth and safe running of the fans it is very important to
observe and check the fallowing.
 Visual inspection of all oil lines and oil level gauges for finding
the leakages if found any leak immediate action to be taken.
 Check the bearing temperatures for fan and motor side DE and
NDE Bearing temperatures. (As per instruction manual normal
running temp of Bearing is 70 0 c Alarm at 80 0 c Trip at 90 0 c).
 Using vibration meter check vibration levels of Fan, Voith and
motor.

Common terminology used for
machinery vibration
 VELOCITY = Velocity of vibration is measured in
peak units such as millimeters per second (mm/s).
Another way of looking at velocity is distance per
time or how much is the machine moving every
second in three important directions at all main
bearing points (AXIAL, VERTICAL, And
HORIZONTAL).
 Velocity measurements and monitoring of
vibration is the most common unit to identify
various problems or acceptability such as:
 unbalance,
 misalignment,

 looseness (machinery structural, foundations, or
bearings),
 Harmonics and many other issues in the machinery
frequency range and many multiples of actual speed.
 EXCELLENT LEVELS = 2.5 mm/s or less at any speed. No
action required.
GOOD LEVELS = 5.0 mm/s or less at any speed. No action
required.
FAIR LEVELS = 7.5 mm/s or less at any speed. No action
required.
ROUGH LEVELS = 10 mm/s or higher at any speed. (Take
action soon.)
VERY ROUGH LEVELS = 15 mm/s or higher at any speed.
(Take action now.)
DANGER LEVELS = 20 mm/s or higher at any speed.
(Shutdown and Fix.)

 DISPLACEMENT = Displacement is measured in peak to
peak units of millimeters or microns ( 1 mm = 1000
microns ) Displacement measurements are recorded in
the same three directions as velocity = axial, horizontal
and vertical.
 EXCELLENT LEVELS = 20 microns or less at any speed. No
action required.
GOOD LEVELS = 50 micron or less at any speed. No
action required.
FAIR LEVELS = 75 microns or less at any speed. No action
required.
DANGER LEVELS = 150 microns higher at any speed.
(Shutdown and Fix.)
 Observe the sound levels of machinery if found any
abnormality check all the above.
 Routine recording in accordance with check sheets.

Every 600 running hours of operation or monthly
 Lubrication
 The frequency at which the oil must be changed is
mainly dependent on the operating conditions and on
the quality of oil used.
 Where oil bath lubrication is employed it is normally
sufficient to change the oil once a year, provided the
bearing temperature does not exceed 50 0 c and there
is no contamination.
 High temperature or more abnormal running conditions
necessitate more frequent change, example; at a
temperature of 100 0 c the oil should be changed every
3 months
 Recommended lubricant for fan bearings ISO VG
46.(present we are using servo system 100 oil for fan
bearing lubrication)

 Initial fill 2.5 – 3 liters
 Re lubrication quantity 200- 250 ml.
HALF YEARLY
 Check the Fan bearings i.e. inspection of rollers
bearing inner race and clearance between rollers
and outer race.
 Inspect the bearing housing.
 Check the Collars and oil rings.
 Check the wear in the impeller.
 Check the Impeller for soot deposition and wear.
Clean the impeller.

 YEARLY:
 CHECK THE ALLIGNMENT OF FAN ,VOITH AND MOTOR.
 CHECK THE BEARING CLEARANCES
 INSPECT THE BERAINGS FOR PITS OR DENTS IF ANY
 CHECK BEARING POSITION WITH DIALING

OPERATIONAL TROUBLES, CAUSES AND REPAIR
TROUBLE CAUSE REPAIRS
High bearing
temperature
Bearing damages Replace bearing
Bearing clearance too small
Install with correct
clearance
Lubrication failure
add lubricant and check for
leakage
Unquiet running
Bearing clearance too large
check bearing if required
replace
Mechanical rubbing
Check all gaps between
stationary and rotating parts
Vibrations
Unbalance due to wear on
blades
Replace and repair the
impeller
Misalignment
Check alignment and re
align
Unbalance
Vibrations are high in radial
direction
Misalignment of coupling/
Bearing and bent shaft
Vibrations are high in axial
direction(around 50% more
of radial vibration
Bad bearing Unsteady Vibration

IMPORTANT SPARES
 FAN SIDE:
 BEARINGS.
 BEARING HOUSINGS.
 COUPLINGS
 OILLEVEL INDICATORS
 SHAFT SEALS
 FELT SEAL
 SHIMS
 IMPORTANT HARD WARE

 MOTOR SIDE
 BEARINGS.
 BEARING HOUSINGS
 END COVERS.
LUBRICANTS:
SERVO GEM – 3 GREASE FOR ALL HT MOTOR
BEARINGS.
SERVO SYSTEM 100 OIL FOR ALL FAN BEARING
HOUSINGS.

FLUID COUPLINGS
WORKING AND
OPERATION
Prepared by
DNV. Ravishankar
Checked and approved by
B.Ramarao

 Working oil flows in to the coupling working
chamber and, due to centrifugal force, forms
a rotating oil ring in the scoop chamber.
 The power of driving machine is transmitted
through the primary wheel on to the working
oil; the working oil accelerated in the primary
wheel and the mechanical energy converted
in to the kinetic energy.

 The secondary wheel absorbs the kinetic
energy and converts back in to the
mechanical energy. This energy is
transmitted to the driven machine.
 The scoop tube position determines the
thickness of the oil ring in scoop chamber.

OPERATING DATA
 Working oil temperature
 Lube oil pressure
 Differential pressure

Working oil temperature
The working oil temperature depends
on the power losses (slip) and the working
oil flow rate
 Operating range 95 Degc.
 Alarm at 100 Degc.
 Trip at 110 Degc.

Lube oil Pressure
During the operation the gear pump
delivers the oil to the Bearings and Gear
wheels. The lube oil pressure is set at the
lube oil orifice.
 Operating range at pressure transmitter
1.2 bar.
 Alarm at 0.8 bar.
 Trip at 0.79 bar

Differential pressure
Chocking of oil filters determined by
Differential pressure.
 Operating range 0.3 bar
 Alarm at 0.6 bar

Maintenance
and Trouble
Shooting of
Fluid Couplings
Prepared by
Ravi Shankar
checked and Approved by
B.Rama rao

155 | Präsentation | JJJJ-MM-TT
Maintenance Measures With Unit Running
Daily:
Check the oil level in coupling.
Temperatures of bearings, lube oil & working oil
Lube oil and working oil pressures
Differential pressure on the lube oil filter

Maintenance Measures With Unit
Running
Every 1000 hours of operation:
 Check operating oil for contamination.
(centrifuge if required)

 Measure, record and compare smooth running (vibrations)
under the same operating conditions.
In case of any problem, please check first the alignment.
Maintenance Measures With Unit Running
Every 3 months:

Maintenance Measures When the Unit is at
Standstill
Every 2 Months:
 Clean vent filter.
 Check smooth running of actuator.
 Visuallyinspect gear stage.
 Check operating oil for contamination.
 Check oil level. In case of too high oil level, check for water
content in the oil

Standstill
Every 8000 hours of operation or at least annually:
 Analyze operating oil for aging and other specifications.
 Inspect and maintain connecting couplings.
 Check the actuator functioning.
 Check alignment and foundation fixing of hydraulic coupling.
 Visual inspection (corrosion, general condition etc) of hydraulic
coupling internals by removing inspection cover on top housing.
 Visual inspection of tooth contact pattern.
 Inspection of fusible plugs.
 Check and maintainA.O.P. motor

Standstill
General Overhaul:
 In the event of a change in operating behavior or after maximum
5 years operating time, variable speed & geared variable speed
turbo coupling should be overhauled.

Trouble Cause(s) Action(s)
1. Scoop tube in 0% position  Move scoop tube in 100% direction.
2. Oil pump not delivering  Check the oil level in the sump.
any oil  Check the direction
 Check oil pump itself.
3. Starting torque too high.  Check the driven machine itself.
Driven machineblocked.
Driven machine
cannot start after
the driving
machine has
reached
its rated speed
Start-up
TROUBLE SHOOTING

1. Driven machine is jammed.  Remove obstacles.
(Check fusible plugs)
2. Oil flow too low  Check oil flow
Coupling heats up
excessively during
“start-up”
Start-up
TROUBLE SHOOTING

1. Driven machine is jammed.  Remove obstacles.
2. Oil flow too low  Check oil flow
Coupling heats up
excessively during
“start-up”
Start-up
TROUBLE SHOOTING

1. Lack of cooling water.  Check cooling system.
Water is too warm  Clean cooler.
Coolercontaminated
2. Over loading of the coupling  Check design data
Coupling heats up
excessively during
“operation”
Start-up
TROUBLE SHOOTING

1. Momentaryfluctuationsin the  Check the system and stabilize.
driven machine.
2. Oil temperature is too low.  Increase the temperature.
(poor deaerationof oil) (45ºC to 50ºC)
3.Gearpump is aspirating air.  Check oil level of sump.
Fluctuations of
output speed during
manual control of
coupling
(Controllever at
standstill)
Output Speed
TROUBLE SHOOTING

1. Improperinput signalto the  Check the controller and
actuator. calibrate.
2 .Air entering into the oil circuit.  Check and eliminate.
Fluctuations of output
speed during auto
control of coupling
(To & fro movementof
controllever)
Output Speed
TROUBLE SHOOTING

1. Scoop tube is jammed.  Remove obstacles.
2. Actuatordefective  Check the actuator.
3. Input signalproblem  Check the controller.
Output speed
cannot be
controlled
Output Speed
TROUBLE SHOOTING

1. Scoop tube notin 100%  Check the scoop tube position.
Position.
2. Fusible plugs responded  Find and eliminate the cause.
Insert new fusible plugs.
3. Too high powerrequirement  Compare the power data with the
of driven machine project data.Check driven machine
for smooth running.
Max.Output
speed cannot
be reached
Output Speed
TROUBLE SHOOTING

1. Lube oil filter clogged  Change over lube oil filter and clean
the filter element.
2. Leak in the oil circuits  Check the pipe lines,coolers etc.
3. Improperorifice sizing.  Correct the orifices.
Lube oil
pressure is
low
Pressures
TROUBLE SHOOTING

1. Lube oil filter clogged  Change over lube oil filter and clean
the filter elements.
Differential
pressure across
double oil filter
too high
Pressures
TROUBLE SHOOTING

Lube oil CoolerProblem
1. Cooling water flow rate too low  Increase the cooling water flow rate
2. Cooling watertoo warm
3. Cooler is contaminated  Check and clean the cooling system
1.Fusible plugs responded  Find and eliminate the cause.Insert
new fusible plugs.
Lube oil
temperature
too high
downstream of
lube oil cooler
Temperatures
TROUBLE SHOOTING
Lube oil
temperature
too high upstream
of lube oil cooler

Temperatures
TROUBLE SHOOTING
Bearing
temperature
too high
1. Bearing damage  Check the bearings and replace.
2. Lube oil temperature too high  Check the lube oil cooler.
3. Lube oil pressure too low  Check the lube oil system and
differential pressure.

1.Faultyalignment  Check and correct alignment.
2.Foundationbolts are loose,  Check the foundation and retighten
the foundation is defective the foundation bolts.
3. Wear or insufficientlubrication  Check the connecting couplings.
of connectingcouplings
4. Unbalanceof rotating parts  Measure the vibration and check the
runner parts.
5. Bearing damage  Check and replace bearings.
Smooth Running
TROUBLE SHOOTING
Uneven running,
vibration and
noise

IMPORTANT SPARES
FUSIBLE PLUG
FLAT SEAL RING
BEARINGS
FILTER ELEMENTS
SPUR GEAR
PLAIN BEARINGS
DRIVE PINION
GEAR PINION
FILTER JUGS
SCOOP SPARES
OIL SELS

J-SEAL BLOWRS
MAINTENANCE AND
TROUBLE SHOOITNG

 Yearly
 Over haul the blower yearly once.
 During overhaul check the fallowing
 Bearings
 Lobe clearance
 Piston rings
 Oil seals
 Splash system
 Gear wheels back lash

RECOMMENDED SPARES
 BAERINGS
 OIL SEALS
 COUPLINGS
 PISTON RINGS
 SHAFT SLEEVES
 O RINGS
 SUCTION FILTERS
 OIL SPLASHER

MAINTENANCE AND TROUBLE SHOOTING
DRAG CHAIN FEEDERS

 Drag chain feeder is a closed rectangular cross-
section of the shell by means of movement of
Drag chain for conveying COAL to the coal
feeder.
 Feeder Receives coal from coal bunker through
rod gate arrangement. And convey the coal to
coal conveying feeder.

 Feeder contains Geared motor which transmits
the power to drag chain feeder sprockets
through Simplex chain.
Inside of the feeder contains :
 Track for drag chain movement,
 Drag chain and sprockets.
 Screw take up housings
 Bearings and bearing housings.

GEARED MOTOR WITH SIMPLEX CHAIN

DRAG CHAIN FEEDER
TECHNICAL DATA
MODEL MS 40
TROUGH WIDTH 400 MM
MAX.CONVEYING DISTANCE 2.5 MTR
MOTOR CAPACITY 4 KW
CURRENT 8.56 AMPS
SPEED 1440 RPM
TOTAL LENGTH 4655 MM
BEARINGS 22219 CA (DE)
1311ATN (NDE)

FREQUENT PROBLEMS AND CAUSES
1. Tripped on over load : Scrap material like wooden
pieces and MS scarp between the chain and body ,
Huge amount of coal is blocked tail end of the
sprockets, and chain misalignment will cause the
Motor over load.
2. No coal flow: Looseness of chain Does not take the
motion from sprockets it causes the No coal flow.
3. Abnormal sound inside the feeder: Track damages
,lack of greasing in bearings, Geared motor chain
looseness cause the abnormal sounds.

MAINTENANCE SCHEDULE
Description of Work DIALY EVERY
TWO
WEEKS
MONTH
LY
Half yearly Yearly
1
CHECK THE GEARED MOTOR
FOR OIL LEAKAGES √
2
CHECK THE GEAR BOX OIL
LEVEL
√
3 GREASING TO THE ALL DE AND
NDE BEARINGS √
4 INSPECTION OF CHAIN
ALLIGNMENT √
5
INSPECTION OF CHAIN TRACK
√
6
INSPECTION AND ADJUST THE
CHAIN LOOSENESS
√

TWO
WEEKS
MONTH
LY
Half
yearly
Yearly
7
INSPECTION OF CHAIN LINKS √
8
REPLACEMENT OF GEAR BOX OIL
√
9
INSPECTION OF BEARINGS √
10
SERVICING OF GEARED MOTOR
√
11
SERVICING OF COAL FEEDERS
√
12
INSPECTION OF DE AND NDE
SPROCKETS
√

MANADATORY SPARES
( QUANTITY IS DEPENDS ON MAINTENANCE
FREQENCY)
1. Chain or chain link assembly.
2.bearings.
3.Bearing housings.
4. Spares for geared motor(bearings, oil
seals,pinions,gear wheels)
5.Simplex chain.
6. Sprockets.

7.Sail Hard plate.
8.Lubricants
Ep-2 Grease
Servosystem 320 oil

SEQUENCE OF CONVEYING PROCESS
COAL BUNKER
DRAG CHAIN FEEDERS
COAL CONVEYING FEEDER
TO FURNACE

CCF WITH GEARED MOTOR AND ACCESS DOORS

SY SYSTEM DESCRIPTION
 Weighing pressure tight belt coal feeder is used for
coal feeding application of the power plant. The
feeding process is a continuous belt feeding process.
 The feeder will receive the materials from DRAGCHAIN
FEEDERS and feed through the weigh bridge.
 The measured weight signals and speed signals sent
to the integrator and totals in ton unit will be
displayed.

STRUCTURE INTRODUCTION
 HOUSING(Body) :
The housing contains Geared motor for belt drive and clean
chain drive, access doors that are well sealed on both ends, inlet
pneumatic gate valves and out let pneumatic gate valves and
inspection doors.
 Internals:
 Head pulley(rubber herringbone tooth)
 Tail pulley(steel drum)
 Endless anti flaming ripple belt with skirt webbing
 Flat idlers
 Weighing idlers
 Head scrapper and tail scrapper

 Screw take up
 Clean chain drive
 Bearing housings
 Sprockets
 Clean chain scrappers
 Self aligning return idlers

SPECIFICATIONS
 No of feeders : 6 nos.
 Capacity Of feeder : 36 TPH
 Belt width : 650mm.
 Belt speed: :0.368m/s.
 Belt side motor :4 K.W
 Clean chain motor :1.1K.W.
 Bearings :22211,22209

MAINTENANCE AND TROUBLE SHOOTING
 Belt misalignment.
 Lubricating of feeder.
 Belt tensioning
 Clean chain looseness
 Scrappers looseness

BELT ALLIGNMENT
 DURING OPERATION OPERTOR SHOULD
OBSERVE THE BELT RUNOFF AND BELT
TENSION
 IF ANY ABNORMALITY ADJUST THE
MECHANISM LINKED WITH TAIL END PULLEY
CALLED AS SCREW TAKE UP HOUSING

LUBRICATION OF THE FEEDER
 Greasing for Belt feeder bearings of head and
tail pulley
 Greasing for clean chain bearings drive and
non drive end
 Grease : Industrial lithium grease EP-2
 Grease method : Filling with oil gun
 Grease period every two weeks
 Avoid using various types of grease

BELT TENSIONING
 Daily inspection is important of belt tensioning
so the belt is under very good status
 If adjustment of belt tension is needed screw
the screw take up housings in The feeding end
of housing screw the threaded rod alternately
and protect if from damage

LOOSENESS OF CLEAN CHAIN AND SCRAPPERS
 IT IS IMPORTANT TO CHECK THE CLEAN CHAIN
AND SCRAPPERS POSITION IN EVERY WEEK
 FOUND ANY ABNORMALITY screw the screw
take up housings in The feeding end of housing
screw the threaded rod alternately and protect
if from damage

BELT CLEAN CHAIN AND SCRAPPER
ARRANGEMENT

IDLERS & IDLERS FRAMES
 Conveyor belt is rotating on head and tail
pulleys placed at very large distance apart.
Belt can sag between these two pulleys
because of its weight. In order to avoid this
sagging, idlers are fixed at certain distance
between these pulleys.

PULLEYS
 BELTFEEDR PULLEYS are
heavy cast iron
construction having
machine crowned faces,
the driving pulley being
faced with rubber lining
or other similar friction
material. The diameters
of pulleys are large
enough to reduce belt
stresses

COAL HANDLING PLANT
MAINTANENCE SCHEDULE

MAINTENANCE SCHEDULE
TWO
WEEKS
MONTH
LY
Half yearly Yearly
1
CHECK THE BELT POSITION √
2
CHECK THE GEAR BOX OIL
LEVEL OF BELT DRIVE
√
3 CHECK THE GEAR BOX OIL
LEVEL OF CLEAN CHAIN DRIVE
√
4 GREASING TO THE ALL DE AND
NDE BEARINGS √
5 INSPECTION OF BELT
ALLIGNMENT √
6
INSPECTION OF CLEAN CHAIN
ALLIGNMENT
√
7
INSPECTION OF CLEANCHAIN
SCRAPPERS
√

TWO
WEEKS
MONTH
LY
Half
yearly
Yearly
1
INSPECTION OF IDLERS √
2
REPLACEMENT OF GEAR BOX OIL
√
3
INSPECTION OF BEARINGS √
4
SERVICING OF BELT DRIVEGEAR BOX
√
5
SERVICING OF CLEANCHAIN
DRIVEGEAR BOX
√
6
SERVICING OF COAL FEEDERS
√
7
INSPECTION OF DE AND NDE PULLEYS √

TWO
WEEKS
MONTH
LY
Half
yearly
Yearly
1
BELT TIGHTNESS
√
2
CLEAN CHAIN TIGHTNESS √
3
INSPECTION OF BELT SCRAPPERS
√
4
INSPECTION OF CHAIN SPROCKETS
√
5
SERVICING OF INLET AND EXIT GATES √
6
INSPECTION SERVICING AND
REPLACEMENT OF IDLERS
√

MANADATORY SPARES
( QUANTITY IS DEPENDS ON MAINTENANCE
FREQENCY)
1. ANTIFLAMING RUBBER BELT.
2.ONE SET OF PULLEYS.
3.50 TO 100 NOS OF IDLERS.
4. BEARINGS.
5. ALL BEARING HOUSINGS.

6. CLEAN CHAIN
7.CHAIN SPROCKETS.
8.CLEAN CHAIN SCRAPPERS.
9.BEARINGS AND OIL SEALS FOR MOTOR.
10.BEARINGS,OIL SEALS,PINIONS,AND GEAR
WHEELS FOR GEAR BOX.

11.BELT SCRAPPERS.
12.TEFLAN ROD AND TEFLON SHEET FOR SELF
ALLIGNMENT IDLERS.
13.FELT SEALS.
14.GLAND ROPES.
15.RUBBER GASKETS.

16.SEALANTS(HY LAMMER TUBES).
17.SCREW SHAFTS FOR TAKE UP HOUSINGS.
18.DUST SEALS FOR BEARING HOUSINGS.
19.IMPORTANT HARD WARE LIKE GRUBSCREWS
,COUNTER SUNK SCREWS,STUDS…ETC

LUBRICANTS AND COSUMABLES
1. SERVOMESH SP 320 OIL.
2. EP-2 GREASE.
3. AC 90 OR RUSTOLINE.
4. DIESEL.
5. COTTAN WASTE.

BOILER PRESENTATION ON 21.10.14 1.pdf

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