Steam generator part 2

BOILER
Prepared by:
Mohammad Shoeb Siddiqui
Sr. Shift Supervisor
Saba Power Plant

Prepared by:
Saba Power Plant
Steam Generator (Boiler)
Hello,
I am trying to explain about Steam Generator
(Boiler) in this session, due to length of said
presentation, I am deciding to divide it in three
parts.
Part 1 cover the “Introduction & Types of Steam
Generator”
Part 2 cover about the “Parts of Steam Generator
and Its Accessories & Auxiliaries” and
Part 3 cover the “Efficiency & Performance”

BOILER
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Part 2

PARTS OF BOILER
Boiler parts are divided into three main classes:
• Boiler Mountings & Accessories
• Boiler Auxiliaries.
• Boiler Safety (Protections)
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FIRE TUBE BOILER
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Mountings:
There are the fittings which are mounted on the boiler for its proper
functioning. A boiler cannot function safely without mountings. Through
there are many types of boiler mountings yet the following are important from
the subject point view.
a. Water level indicator
b. Pressure gauge
c. Safety valves
d. Stop valve
e. Blow off cock
f. Feed check valve
g. Fusible plug
h. Blow down valve
i. Man hole and Mud Box
j. Blow-off cock
Boiler Mountings and Accessories
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Simple Vertical Boiler:
The image shows the simplest form of an
internally fired vertical fire-tube boiler. It does
not require heavy foundation and requires
very small floor area.
Parts
• Cylinder Shell
• Cross Tubes
• Furnace or Fire Box
• Grate
• Fire Door
• Chimney or Stack
• Manhole
• Hand Hole
• Ash Pit
FIRE TUBE BOILER
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FIRE TUBE BOILER
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Cochran
Boiler

Locomotive Boiler
FIRE TUBE BOILER
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Lancashire Boiler Components
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Cornish Boiler
FIRE TUBE BOILER
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These are the devices which form an integral part of a boiler but are not mounted on it. It
may be noted that the accessories help in controlling and running the boiler efficiency
Though there are many types of accessories yet the following are
important from the subject point of view.
• Steam drum.
• Mud drum
• Super heater & Its attemperator
• Re-Heater & Its attemperator
• Economizer
• Down comers.
• Headers
• Generation tubes (Up risers) Water walls.
• Air preheater System (Regenerative air heater & SCAPH)
• Soot Blowers
• Furnace.
• Burners & Its Accessories (Air register, Dampers, Flame Detector)
• Boiler Drains & Vents System
• Stack/Chimney.
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Accessories:

Boiler auxiliaries have the following parts:
• Induced draft fan (IDF).
• Forced draft fan (FDF).
• Recirculation fan (RCF).
• Fan Dampers
• Feed water pump
• Atomizing Air or Steam System
• Chemical Feed System
• Seal Air Blower
• Flame Scanner Cooling Blower
• Fuel System
• ESP
• Ash Handling System
• Blowdown Tank
• Service & Instrument Air System
BOILER AUXILIARIES
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The accessories include –
1. Economizer
2. Boiler Drum
3. Down comers
4. Water walls
5. Water wall plates (used for low-
pressure boilers)
6. Primary super heater
7. Platen super heater
8. Final Super heater
9. Reheater
10. Burner
11. Igniters.
A brief note on some of the major
components shows in figure
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Sr. Shift SupervisorBoiler Accessories

WATER TUBE BOILER
Babcock and Wilcox boiler.
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WATER TUBE BOILER
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Saba Power Plant

WATER TUBE BOILER
Double Furnace Boiler
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Waste Heat Boiler (HRSG)
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Nuclear Steam Generating Systems
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Steam Drum Internals
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a. Steam purification
equipment, including dry pan
separators, plate-type baffles
and other devices as
necessary, to meet steam
quality requirements and
provide proper water levels in
the boiler steam drum.
b. Boiler feedwater admission
system to properly distribute
feedwater.
c. Chemical feed piping to
permit infusion of mixture of
water treatment compounds
along entire length of drum
by continuous feed system.

d. Continuous blowdown and water
sampling system as combined unit
designed to collect water along entire
length of drum.
e. Bottom drum blowoff system to
properly collect sediment from bottom
drum and to permit complete collection
of sediment and drainage.
f. Steam heating pipes in bottom drum to
keep boiler warm on standby. Cap for
future connections of steam supply and
condensate return.
g. Drum internal fittings shall be
provided, securely mounted and easily
removable for boiler internal access for
inspections and cleaning.
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Mud Drum
A drum beneath a boiler,
into which sediment and
mud in the water can settle
for removal.
It is related with "bottom"
blow down which reduces
the quantity of un-dissolved
solids (sludge) which collect
in the lower parts of the
boiler (mud drum).
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Super heater Coils:
A superheater is a device used to
convert saturated steam or wet steam
into dry steam used in Steam
turbines or in processes, such as steam
reforming. There are three types of
superheaters: radiant, convection, and
separately fired.
1. A radiant superheater is placed
directly in the combustion
chamber.
2. A convection superheater is located
in the path of the hot gases.
3. A separately fired superheater, as its
name implies, is totally separated
from the boiler.
A Attemperator is provided to control
the super heated steam temperature. Prepared by:

Steam from the exhaust of the first stage
turbine goes back to the boiler for
reheating and is returned to the second
stage. Reheater coils in the flue gas path
does the reheating of the returned steam.
The reheat steam is at a much lower
pressure than the super heated steam but
the final reheater temperature is the same
as the superheated steam temperature.
Reheating to high temperatures improves
the output and efficiency of the Power
Plant. Final Reheater temperatures are
normally in the range of 530 to 600 °C.
Reheat steam pressures are normally
around 45 bar.
A attemperator is provided to control the
Re-Heater steam temperature. Prepared by:
Re-Heater

Economizer coils are used in
downstream of Boiler bank to preheat
the feed water absorbing heat from
hot exhaust gases. Economizers are
always water tube type. Economizers
have different types of Tubes
depending upon the application. Bare
tubes in Economizers are widely used
in Industrial boilers and for
applications like Heat recovery boilers
in Sulfuric acid plants, gilled tubes
are employed. Finned tubes are
popular in HRSG applications. Feed
water can be heated up to a level
about 20 - 30 oC below saturation
temperature of the boiler.
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Economizer Coils

Downcomers are
pipes leading from
the top to the
bottom of the
boiler.
Downcomers carry
the water from
steam drum to the
bottom part of the
boilers.
Downcomers
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Headers form an important part of all types of boilers. Steam
from the generating tubes is collected in headers which are
therefore always under pressure. This pressure may vary from
300 psi to 2000 psi. Since headers are always under pressure, the
utmost care is taken by us while fabricating them. Depending
on the generating capacity of the boiler the header sizes
fabricated by us vary from 100 mm to 600 mm NB. The stubs of
various sizes are very carefully welded to the main body of the
header to provide the desired openings from the header.
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Headers:

These are tubes in the Boiler
where water is evaporated to
steam and are also called Steam
Generating Tubes. These Tubes
also form the Walls of the
Boiler and are hence called
Water Walls or Water Wall
Panels. These Tubes have very
complicated shapes to allow
Inspection openings and
burner throats and fabrication
require intricate binding on
CNC programmable bending
Machines and checking on 3D
layouts.
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Water Wall Tubes:

SCAPH (Steam Coil Air Pres Heater
Steam Coil Air Pre
Heater (SCAPH) is an
extended surface type
heat exchanger. This
equipment is used to
heat atmospheric air
to the required
process temperature
by means of saturated
steam. Steam flows
inside the tube while
air passes over the
finned tubes .
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SCAPH (Steam Coil Air Pres Heater
Steam coil air preheaters ( SCAPHS ) are
used to heat air entering the air heater
recuperative or regenerative type, in order to
raise the average cold end temperature to
prevent acid dew point corrosion. This type
of equipment is normally incorporated into
the design of a boiler unit for low load
operation and startup operation particularly
in those areas with low ambient air
temperatures. They are desirable in that the
main air heaters, recuperative or
regenerative, have corrosion sections that
are more readily maintained This type of air
heater uses extended surface, normally
referred to as fins, to reduce the overall size
of this air preheater. It is generally located in
the duct between the FD fan and the main
air heater. in those areas that have extremely
low ambient air temperatures, it is common
to have this ahead of the FD fan that could
preheat cold winter air up to about 40
degrees F.
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Air Pre-Heater
In this type of preheater, heat is
transferred from the flue gases to a
matrix, which is then cooled by the
combustion air, thereby preheating the
air. For fired heater and boiler
applications, regenerators are usually of
the rotary type.
The rotary regenerator preheater know as
the Lungstrom wheel consists of elements,
usually metallic, which are contained in a
cylinder which flows through one side as the
cylinder and is subsequently cooled by the
combustion air on the other side as the wheel
rotates. There are seals between the cylinder
and casing to limit the amount of leakage
from the airside to the flue gas side. This
leakage lowers the gas exit temperature by 10
to 15 oC which in turn limits the level of
efficiency normally occur at the end of the
elements which will require periodic
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Soot Blowers
A soot blower is a system for removing the Soot that is deposited on the furnace tubes
of a boiler during combustion.
In oil fired boilers, over a period of time the heat transfer tubes get covered by a layer
of soot or fine carbon deposit. This reduces the heat transfer from the hot gases to the
water and reduces the efficiency of the boiler.
In coal fired boilers, the furnace area gets covered by slag which is molten ash. The ash
also sticks to the heat transfer surface in the other heat transfer areas. These ash
accumulations reduce heat transfer and increase the tube metal temperatures leading
to failure of the tubes.
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Types of soot blowers:
1. One with a very long lance called the “long retractable soot blowers.” This
is normally used to clean the ash deposit from between the coils of
superheaters and economizers.
2. The other type is the shorter lance type called the “wall blowers.” These
are used to clean the furnace walls. The lance extends a short distance
around 200 mm from the furnace wall. The nozzle direction is such that
the steam impinges on the walls cleaning the surface. During operation,
the lance rotates cleaning the radial area covered by the steam from the
nozzle.
3. Air Heater Blower.
Soot blowing medium:
Steam
Air
Steam is normally used as a medium for blowing away the soot since capital
cost of steam pressure reducing equipment and drain is less than the cost
of compressor, motors and control of air systems.
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Soot Blowers

A furnace is a device used
for heating. The name derives
from Latin fornax, oven.
Furnace
An industrial furnace or direct
fired heater, is an equipment
used to provide heat for a
process or can serve as
reactor which provides heats
of reaction. Furnace designs
vary as to its function, heating
duty, type of fuel and method
of introducing combustion air.
However, most process
furnaces have some common
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Fuel flows into the burner and is burnt with air provided from
an air blower. There can be one or more than one burner in a
particular furnace which can be arranged in cells which heat a
particular set of tubes. Burners can also be floor mounted,
wall mounted or roof mounted depending on design. The
flames heat up the tubes, which in turn heat the fluid inside in
the first part of the furnace known as the radiant section
or firebox. In this chamber where combustion takes place, the
heat is transferred mainly by radiation to tubes around
the fire in the chamber. The heating fluid passes through the
tubes and is thus heated to the desired temperature. The gases
from the combustion are known as flue gas. After the flue gas
leaves the firebox, most furnace designs include a convection
section where more heat is recovered before venting to
the atmosphere through the flue gas stack.
Furnace
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Burners:
The burner is the device that permits controlled
burning of fuel inside the furnace. The burner mixes
the fuel with the required amount of air and directs
the flame into the combustion area. The burner
comprises of gas burner and oil burner with atomizing
steam connection.
Burner consists of:
· Air Register: used to give an enough quantity
of air to the burner for good combustion.
· Ignition Gun: used to give ignition spark to the
burner for firing.
· Flame Detector: used to monitor the flame.
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Oil Burner

Pulverized Coal Burner
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Oil Burners
Pressure jet burners
A pressure jet burner is simply an orifice at the end of a
pressurised tube. Typically the fuel oil pressure is in the
range 7 to 15 bar.
In the operating range, the substantial pressure drop
created over the orifice when the fuel is discharged into
the furnace results in atomization of the fuel. Putting a
thumb over the end of a garden hosepipe creates the
same effect.
Varying the pressure of the fuel oil immediately before
the orifice (nozzle) controls the flowrate of fuel from
the burner.
Advantages of pressure jet burners:
Relatively low cost.
Simple to maintain.
Disadvantages of pressure jet burners:
If the plant operating characteristics vary considerably
over the course of a day, then the boiler will have to be
taken off-line to change the nozzle.
Easily blocked by debris. This means that well
maintained, fine mesh strainers are essential.
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Oil burners
Rotary cup burner:
Fuel oil is supplied down a central tube, and
discharges onto the inside surface of a
rapidly rotating cone. As the fuel oil moves
along the cup (due to the absence of a
centripetal force) the oil film becomes
progressively thinner as the circumference of
the cap increases. Eventually, the fuel oil is
discharged from the lip of the cone as a fine
spray.
Because the atomization is produced by the
rotating cup, rather than by some function
of the fuel oil (e.g. pressure), the turndown
ratio is much greater than the pressure jet
burner.
Advantages of rotary cup burners:
Robust.
Good turndown ratio.
Fuel viscosity is less critical.
Disadvantages of rotary cup burners:
More expensive to buy and maintain.
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Gas burners
Being a gas, atomization is not an issue, and proper mixing of gas with the
appropriate amount of air is all that is required for combustion.
Two types of gas burner are in use 'Low pressure' and 'High pressure'.
Low pressure burner
These operate at low pressure, usually between 2.5 and 10 mbar. The burner is a
simple venturi device with gas introduced in the throat area, and combustion air
being drawn in from around the outside.
Output is limited to approximately 1 MW.
High pressure burner
These operate at higher pressures, usually between 12 and 175 mbar, and may include a
number of nozzles to produce a particular flame shape.
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Gas Burner
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Dual fuel burners
The attractive 'interruptible' gas tariff means that it is
the choice of the vast majority of organizations in the
world. However, many of these organizations need to
continue operation if the gas supply is interrupted.
These burners are designed with gas as the main fuel,
but have an additional facility for burning fuel oil.
The notice given by the Gas Company that supply is to
be interrupted may be short, so the change over to fuel
oil firing is made as rapidly as possible, the usual
procedure being:
Isolate the gas supply line.
Open the oil supply line and switch on the fuel pump.
Purge and re-fire the boiler.
On the burner control panel, select 'oil firing'
(This will change the air settings for the different fuel).
This operation can be carried out in quite a short
period. In some organizations the change over may be
carried out as part of a periodic drill to ensure that
operators are familiar with the procedure, and any
necessary equipment is available. Prepared by:

The difference between atmospheric pressure and
the pressure existing in the furnace or flue gas
passage of a boiler is termed as draft. Draft can also
be referred to the difference in pressure in the
combustion chamber area which results in the
motion of the flue gases and the air flow.
Types of Draft
Drafts are produced by produced the rising of the
combustion gases in the stack, or by mechanical
means, for example a blower and can be put into four
categories: natural, induced, balanced, and forced.
Boiler Draft
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Natural draft:
when air or flue gases flow
due the difference in the
density and acted upon by
the force of gravity in
stacks is a natural draft
system. Simply put, the
difference between the
density between the hot
flue gases and the cold
gases in the surroundings
results in a natural draft at
the stack entrance.
Boiler Draft
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Forced draft:
When air or flue gases
are maintained above
atmospheric pressure.
Normally it is done
with the help of a
forced draft fan.
Boiler Draft
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Induced draft:
When air or flue gases flow
under the effect of a gradually
decreasing pressure below
atmospheric pressure, in this
case the system is said to
operate under induced draft. In
this case the stacks(chimneys)
provide sufficient natural draft
to meet the low draft loss
needs. On the other hand, in
order to meet higher pressure
differentials the stacks are
operating with draft fans
simultaneously.
Boiler Draft
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Balanced draft:
When the static
pressure is equal to the
atmospheric pressure
the system is referred
to as the balanced
draft. Draft is said to be
zero in this system
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Air & Flue Gas System
The air and gas systems are
provided for force draft to the
boiler for complete
combustion of the fuel. The
Gas Recirculation Fan
increases the mass flow of air
to maintain the hot reheat
temperature. The flue gases
going to the stack raise the
inlet air temperature,
ultimately increasing boiler
efficiency.
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Air & Flue Gas System
SCAPH
RAH
GRF
ESP
Stack
Boiler
Flue Gases Flow
Air Flow
GRF
RAH
FDF outlet air Pressure
635 mmH2O
Temp. 29.0 oC
Flue Gas outlet gas
Pressure 56 mmH2O
Temp. 147 oC
GRF outlet Pressure
339 mmH2O
Flue gas Pressure 166 mmH2O
Temp. 344 oC
SCAPH
RAH ESP
Burners
Wind Box
Steam
Drum
Ash Hoppers
SH
SH SH
RH SH
SH
ECO
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Boiler Drains & Vents System
The water that is feed to the boiler contains impurities in the
form of suspended solids and dissolved solids. A large portion of
these impurities is left behind when the steam leaves the boiler.
Some of these suspended impurities have tendency to settle
down in the lowest part of the boiler. Others are light and float
on the surface of the water. The operator must control the
buildup of impurities, by injection of chemical into the
feedwater and blowing down.
Blowing down at a slower rate and over a longer period of time
reduces the concentration more effectively than is possible by
opening wide the main blowdown valve. Therefore closer
control and more accurate regulation of the blowdown is
achieved. The continuous blowdown requires the use of the
Blowdown Flash Tank where the high pressure water can be
flashed into low pressure steam. Prepared by:

Vents are provided on different pressure parts of the Boiler. They
are used during depressurizing, filling and charging the system.
All drains and vents are manually operated and are used during
startup and shutdown.
• The purpose of this system is to vent and drain the
Superheater, Reheater, Boiler drum, Economizer, Deaerator
and Boiler convection pass during startup and shutdown
activities of the Boiler as required.
• To cool down the high temperature drains in the Blowdown
Tank before sending the water to the waste water system.
Boiler Drains & Vents System
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Use of Drains:
Superheater Drains
•During startup, these drain valves are opened to drain any
buildup of water in the superheater. Water remaining in the
superheater would restrict the flow of steam and cause the
tubes to overheat. In addition, operating with the superheater
drains cracked open, allows steam to circulate through the
superheater tubes thus preventing excessive heat buildup.
•During shutdown, these drain valves are usually opened to
depressurize the superheaters.
Reheater drains
These drains are usually opened for depressurizing the
Reheaters during shutdown.
Drum level gauge drain
This drain is usually opened when the gauge glass is required to
place in service. Prepared by:

Use of Drains:
Economizer inlet drain
These drains are used for draining the boiler after shutdown.
Lower convection pass header drain
These drains are used for draining the boiler after shutdown.
Downcomer header drains
These drains are used for draining the boiler after shutdown or
cycling the feedwater system during normal operation.
Continuos Blowdown
This arrangement is used to remove the silica & other impurities
form the steam drum water.
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Use of Vents:
Drum vent
• During depressurizing the boiler, open the vent at 2Kg.
Pressure.
• Keep this vent open during the following situations:
• Boiler filling
• Until steam pressure increase to >1.5Kg to prevent a rapid
increase of drum pressure during startup.
Superheater vents
Keep these vents open until steam comes out of those during
startup.
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HRSG Auxiliary components:
Complete boiler trim package
ASME code piping
Lined duct work/casing for high and low temperature and dirty gas applications
Expansion joints
Diverter valves
Guillotine dampers with Zero-leakage sealed air system
Silencers
Duct burners
Fuel trains/racks
Combustion controls & burner management systems
Blowdown tanks
Deaerators and BFW pumps
Feedwater economizers
DA make up water pre-heaters
Process heat exchangers
Hoppers
Structural steel
Free-standing and self-supporting stacks
SCR system
CO catalyst
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Boiler auxiliaries have the following parts:
•Forced draft fan (FDF).
•Induced draft fan (IDF).
•Recirculation fan (RCF).
•Fan Dampers
• Burners / Igniters and BMS (Burner Management System)
• Atomizing Air or Steam System
•Feed Water Tank & DA & Feed water heater
• Feed water pump
• Chemical Feed System
• Seal Air Blower
• Flame Scanner Cooling Blower
• Fuel Handling System
• ESP
• Ash Handling System
• Blowdown Tank
• Service & Instrument Air System
BOILER AUXILIARIES
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In figure gives a
symbolic
representation of
the different boiler
auxiliary equipment
and their major
interconnections.
A brief note on
various auxiliary
equipment has
been given in the
following sections.
BOILER AUXILIARIES
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Boiler Draft Fans
The largest fans in power plants deliver air to the burners (force draft
fan, FD) and extract flue gas from the boiler (induced-draft fan, ID).
Plants with flue gas desulfurization may have additional booster fans.
Those large fans range from 1 to 18MWel and are usually built as axial
fans. Their blades have an airfoil shape and the gas flow is controlled
with variable pitch of the rotating blades.
Axial fans have higher capital costs than centrifugal fans, and because
of more numerous parts and complexity, they also require more
maintenance.
All other fans in power plants are usually smaller, and built as radial
fans, also called centrifugal fans. The pressure and flow
characteristics of radial fans are dependent on the orientation and
shape of the fan blades, like backward-curved blades, straight ‘radial’
design, forward-curved blades. Prepared by:
Saba Power Plant

Boiler Draft Fans
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Forced Draft Fan
Forced Draft fan supplies air at
high speed to furnace during
fuel combustion. It controls
airflow and handles air at
normal temperature. Forced
Draft Fan has ability to work
with high static pressure. .
These fans are used to supply
air during various industrial
processes at high speed. The
fans offered by us help in
supplying fresh air by pulling
out the air dust particles, with
the help of chimneys.

FDF Suction Filters
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FDF Suction Filters are
used for provide clean air
to boiler for good
combustion, and this air
passes through the
tubular or regenerative
air heater and to
the wind box connecting
duct which supplies the
secondary air to wind
boxes.

Boiler Draft Fans
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Induced Draft
(ID) fans are
used to create a
vacuum or
negative air
pressure in a
system or
stack.
Induced Draft
Fan

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FDF Inlet Damper
Inlet guide vane control
Motor and fan run with fixed speed. A solid
gear may be used, since fan speed may be
lower than motor speed. Flow is adjusted
with the inlet guide vane position. The guide
vane directs the gas into the same direction
of rotation as the fan impeller, which reduces
the fan flow. Inlet guide vane control is more
efficient than inlet dampers due to reduced
friction in creating the pre-swirl movement.
Inlet damper control
Motor and fan run with fixed speed. Flow is
adjusted with the inlet damper position. The
inlet damper directs the gas into the same
direction of rotation as the fan impeller,
which reduces the fan flow. Inlet damper
control is less efficient than an inlet guide
vane due to increased friction in creating the
pre-swirl movement.

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GRF (Gas Recirculation Fan)
Gas Recirculation Fan (GRF) draw gas from a point
between the economizer outlet and the air heater inlet and
discharge it into the bottom of the furnace outlet.
Recirculation gas introduced in the vicinity of the initial
burning zone of the furnace is used for steam temperature
control, while re circulated gas introduced near the
furnace outlet is used for control of gas temperature.
RH outlet steam temperature is normally controlled by
regulating the gas recirculation flow. Increased flue gas
flow over Reheater of the convection heating surfaces
increases the heat absorption and RH temperature is
increased.
(GFR or FGR) acts to reduce NOx formation by reducing
peak flames temperatures. In conventional applications.

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GRF (Gas Recirculation Fan)

WINDBOX
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Burners
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Fuel Atomizing System
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Coal Fire Boiler
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Boiler Feed Water Tank with Deaerator
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Flash Economizer Blowdown Separator
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Boiler Feed Water Heaters
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Boiler Feed Water Pump
A boiler feedwater pump is a specific type
of pump used to pump feedwater into a steam boiler.
The water may be freshly supplied or
returning condensate produced as a result of the
condensation of the steam produced by the boiler. These
pumps are normally high pressure units that take
suction from a condensate return system and can be of
the centrifugal pump type or positive displacement type.
Boiler feedwater pumps are sometimes driven by large
electric motors that operate with hydrodynamic
bearings and mechanical seals.
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Boiler Chemical Dosing System
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Cooling Air Fans:
Cooling air fans are used to cool
the burners and surrounding
equipment’s like flame detector,
oil firing gun, gas burners.
During normal operation, one (1)
blower is kept in service and the
other blower is on standby. The
blower takes suction from
atmosphere through an inlet filter
and supplies filtered and
pressurized air to all six burners
for the cooling of the flame
scanners and Main burners and
Igniter gun sleeves. Prepared by:

Seal Air Fan basically functions as
booster fan taking suction from
primary air fan discharge
(cold primary air before AH)
boosting up the air pressure and
supplying seal air to various
sealing points.
Seal Air Fan
During normal operation one (1)
Seal Air Blower is in service and the
additional blower is on standby in
order to supply an adequate amount
of air for the sealing of the
penthouse, superheater vestibule,
GRF seals, Thermoprobe and soot
blowers.
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Fuel Handling System

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Gas

Fuel Supply System
Road Tankers Bay
Rail Wagons Bay
RFO
Transfer
Pumps
Suction
Strainers
RFO
Unloading
Pumps
RFO
Unloading
Pumps
Suction
Strainers
RFO
Transfer
Pumps
RFO Pressurizing
Pumps Suction
Strainers
RFO
Pressurizing
Pumps
RFO Burner Deck
Suction Strainers
RFO
Discharge
Heaters
RFO Day Tank
RFO
Burners
RFO Storage Tank-2
RFO Storage Tank-1
RFO Unloading
direct to day tank &
Recirculation Line RFO Return
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RFO

Fuel System for Boiler Ignition
HSD
unloading
Pumps
Suction
Strainers
HSD
Unlading
Pumps
HSD Pressurizing
Pumps Suction
Strainers Y type
HSD
Pressurizing
Pumps
HSD Strainers
HSD Day Tank
HSD
Igniters
HSD Road
Tanker
HSD Day Tank
Prepared by:
HSD

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Coal

Biomass
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Saba Power Plant

ESP (Electrostatic Precipitator)
Prepared by:
Saba Power Plant

Ash Handling System
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Saba Power Plant

Ash Handling System
Vacuum Conveying System
Prepared by:
Saba Power Plant

Ash Handling System
Vacuum Pneumatic Conveying System
Prepared by:
Saba Power Plant

Ash Handling System
Clinker / Hydraulic Conveying System
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Saba Power Plant

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Safety Valve
An important boiler fitting is the safety valve. Its function is to protect the boiler shell
from over pressure and subsequent explosion.

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Safety Valve
Many Different Types of Safety Valves are fitted to steam boiler
plant, but generally they must all meet the following criteria:
The ASME standard I and ASME standard VIII for boiler and
pressure vessel applications and the ASME / ANSI PTC 25.3
standard for safety valves and relief valves provide the following
definition. These standards set performance characteristics as well
as defining the different types of safety valves that are used:
ASME I valve - A safety relief valve conforming to the
requirements of Section I of the ASME pressure vessel code for
boiler applications which will open within 3% overpressure and
close within 4%. It will usually feature two blowdown rings, and is
identified by a National Board 'V' stamp.

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Safety Valve
ASME VIII valve - A safety relief valve conforming to the
requirements of Section VIII of the ASME pressure vessel
code for pressure vessel applications which will open within
10% overpressure and close within 7%. Identified by a
National Board 'UV' stamp.
Low lift safety valve - The actual position of the disc
determines the discharge area of the valve.
Full lift safety valve - The discharge area is not determined
by the position of the disc.
Full bore safety valve - A safety valve having no protrusions
in the bore, and wherein the valve lifts to an extent sufficient
for the minimum area at any section, at or below the seat, to
become the controlling orifice.

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Safety Valve
Conventional safety relief valve - The spring housing is
vented to the discharge side, hence operational
characteristics are directly affected by changes in the
backpressure to the valve.
Balanced safety relief valve - A balanced valve incorporates
a means of minimizing the effect of backpressure on the
operational characteristics of the valve.
Pilot operated pressure relief valve - The major relieving
device is combined with, and is controlled by, a self-actuated
auxiliary pressure relief device.
Power-actuated safety relief valve - A pressure relief valve
in which the major pressure relieving device is combined
with, and controlled by, a device requiring an external source
of energy.

Prepared by:
Safety Valve

Level Measurement
Pressure Measurement
Flow Measurement
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LOCAL MEASUREMENT
Drum Level Gauge Glass
The level of water in a steam boiler must be carefully controlled, to ensure
good quality steam is produced safely, efficiently and at the correct pressure.
In most cases, the simple gauge glass on the steam / water drum or boiler shell is used as
the indicator. Many standards stipulate the provision of two gauge glasses.
Arrangements are usually required to prevent a breakage from causing a hazard to the
operator. The most common form of protection is a toughened glass screen to the front
and sides of the water gauge glass. .

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LOCAL MEASUREMENT
Pressure Measurement
Pressure gauges are used to determine:
Steam Pressure
Feedwater Pressure
Oil Pressure
Gas Pressure
Draft Pressure
Pressure may be recorded as gauge pressure
or as absolute pressure. Gauge pressure is
the pressure above that of the atmosphere.
Absolute pressure is the pressure above zero
pressure, equal to gauge pressure plus the
atmospheric pressure. At sea level,
atmospheric pressure is 14.7 psi.
Pressure gauges include many pressure
measurement devices including bellows,
Bourdon tubes, capsule elements and
diaphragm element gages; detailed form for
analog or needle dial face gauges.

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LOCAL MEASUREMENT
Temperature Measurement
Temperature Gauges are used to determine:
Feedwater Temperature
Oil Temperature
Water Temperature
Flue Gas Temperature
Temperature gauges can be classified as
either mechanical in design or electronic.
Mechanical temperature gauges include bi-
metallic or filled system design. A bi-
metallic thermometer uses two dissimilar
metals joined together. Since these metals
are not the same their co-efficient of
expansion will be different allowing the
composite metal strip to bend in the
direction of the metal with the lower co-
efficient. This is predicable and repeatable
and therefore can be scaled. Bi-metal
temperature gauges are inexpensive and are
commonly used in boiler applications.

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LOCAL MEASUREMENT
Fluid Flow Measurement
Fluid characteristics and flow theory (including Bernoulli's theorem and Reynolds'
numbers) are introduced and developed to provide basic metering theory and
techniques. Different meter types, instrumentation and installation practice are also
discussed.

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LOCAL MEASUREMENT
Flow Measurement
Fluid characteristics and flow theory (including Bernoulli's theorem and Reynolds'
numbers) are introduced and developed to provide basic metering theory and
techniques. Different meter types, instrumentation and installation practice are also
discussed.
Many flow meters are based on the work of Daniel Bernoulli in the 1700s. Bernoulli's
theorem relates to the Steady Flow Energy Equation (SFEE), and states that the sum of:
Pressure energy,
Kinetic energy and
Potential energy
P1 and P2 = Pressure at points within a system (Pa)
u1 and u2 = Velocities at corresponding points within a system (m/s)
h1 and h2 = Relative vertical heights within a system (m)
ρ = Density (kg/m)
g = Gravitational constant (9.81 m/s²)
Bernoulli's equation ignores the effects of friction and can be simplified as follows:
Pressure energy + Potential energy + Kinetic energy = Constant

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LOCAL MEASUREMENT
Steam Flow Measurement
Most common method of steam metering is the
traditional orifice and differential pressure transmitter
technique. The main areas of concern with this type of
measurement are the orifice plates susceptibility to
wear introducing immediate inaccuracies, the
relatively high pressure losses introduced into the
system by the orifice plate and the small (typically 3:1)
measuring range. The other major issue with this
approach is the number of potential emission points,
which could be as high as 30 depending on the
configuration adopted. Another significant area of
potential inaccuracy is the d/p transmitter itself. Even
most so called smart d/p transmitters still utilize
analogue sensing systems. The primary analogue
sensor is very susceptible to drift caused by static
pressures and high temperatures. These factors,
coupled with the inaccuracies evident at low
measuring ranges, can cause the overall performance
of the metering installation to be highly suspect.

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LOCAL MEASUREMENT
Boiler Combustion Air Flow Measurement
Boiler air flow (or air flow on a forced or
balanced draft furnace) may be measured with
a pitot tube, air foil section, or any calibrated
flow restricting device located in the duct that
leads from the forced draft fan to the windbox.
(The windbox is the area behind the burner
throats that supplies combustion air to the
burners.) The differential across the windbox to
the furnace can be as high as 25" H2O, but is not
used because each time a register is adjusted,
the flow relationship to delta P changes. On
many boilers, air flow is the measured
differential between the furnace inlet and the
boiler outlet. This takes the differential of the
hot gases as they flow through the furnace,
across the convection section, and out the
stack. In most cases, the differential ranges
from 0.5 to 2.0 inches of water.

Prepared by:
Saba Power Plant
shoeb.siddiqui@sabapower.com
shoeb_siddiqui@hotmail.com
www.youtube.com/shoebsiddiqui

Steam generator part 2

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