BOILER FUNCTION :-
A boiler function and its type will discussed here firstly boiler is an enclosed vessel that provides a means for combustion heat to be transferred into
water until it becomes heated water or steam. The hot water or steam under pressure is then
usable for transferring the heat to a process. Water is a useful and cheap medium for
transferring heat to a process. When water is boiled into steam its volume increases about 1,600
times, producing a force that is almost as explosive as gunpowder. This causes the boiler to be
extremely dangerous equipment that must be treated with utmost care.
The process of heating a liquid until it reaches its gaseous state is called evaporation. Heat is
transferred from one body to another by means of (1) radiation, which is the transfer of heat
from a hot body to a cold body without a conveying medium, (2) convection, the transfer of
heat by a conveying medium, such as air or water and (3) conduction, transfer of heat by actual
physical contact, molecule to molecule.
Boiler Specification The heating surface is any part of the boiler metal that has hot gases
of combustion on one side and water on the other. Any part of the boiler metal that actually
contributes to making steam is heating surface. The amount of heating surface of a boiler is
expressed in square meters. The larger the heating surface a boiler has, the more efficient it
becomes. The quantity of the steam produced is indicated in tons of water evaporated to steam
per hour. Maximum continuous rating is the hourly evaporation that can be maintained for 24
hours means the amount of steam generated from water at 100 °C to saturated steam at 100 °C.
Application of boiler in various sector
1. Power Generation process
2. Process Heating
Indian Boiler Regulation The Indian Boilers Act was enacted to consolidate and amend the
law relating to steam boilers. Indian Boilers Regulation (IBR) was created in exercise of the
powers conferred by section 28 & 29 of the Indian Boilers Act.
IBR Steam Boilers means any closed vessel exceeding 25liter in capacity and which is used
expressively for generating steam under pressure and includes any mounting or other fitting
attached to such vessel, which is wholly, or partly under pressure when the steam is shut off.
IBR Steam Pipe means any pipe through which steam passes from a boiler to a prime mover
or other user or both, if pressure at which steam passes through such pipes exceeds 3.5 kg/cm2
above atmospheric pressure or such pipe exceeds 254 mm in internal diameter and includes in
either case any connected fitting of a steam pipe.
2.NON IBR Boiler
-It is law of India to govern design installation manufacturing operation of all
steam producing vessel. As per IBR, boiler is a steam producing vessel having capacity more
than 5 gallons i.e. 25 litters and it is used extensively for steam generation under pressure and
include any mounting or fitting attached to such vessel. Pressure of IBR Boiler is more than
Boiler which not covered under IBR steam producing vessel whose volumetric
capacity is less than 5 gallons (less than 25liters) Inspection of NON IBR Boiler is only in
one time during installation
Pressure of NON IBR Boiler is less than 3.5 kg/cm2
Boiler Types and Classifications
There are virtually infinite numbers of boiler designs but generally they fit into one of two
Fire tube or “fire in tube” boilers; contain long steel tubes through which the hot gasses from
a furnace pass and around which the water to be converted to steam circulates. Fire tube boilers,
typically have a lower initial cost, are more fuel efficient and easier to operate, but they are
limited generally to capacities of 25 tons/hr and pressures of 17.5 kg/cm2
Water tube or “water in tube” boilers in which the conditions are reversed with the water
passing through the tubes and the hot gasses passing outside the tubes These boilers can be of
single- or multiple-drum type. These boilers can be built to any steam capacities and pressures
and have higher efficiencies than fire tube boilers.
There are two types of boiler used in factory
1. Agrowaste Boiler
2. Furnaced oil boiler
Agro waste Boiler
Agrowaste boiler is made by Thermax company having capacity of TPH. This boiler is also
called as the Combipack (Composite) boiler because of it used both of water tube and fire tube
Process Flow Structure of Agrowaste Boiler
Component of boiler
1.Briqute Feeding Hopper – Total three hopper provided for this boiler at time only one
hopper is running condition also three vibrator motor is provided for these three hoppers. the
main purpose of this vibrator motor is to fall the briquettes to belt conveyor.
2. Briquets Feeding Belt Conveyor-Belt conveyor is provided to carry the briquets and
feed on the drag chain conveyor. total three belt conveyors are provided Variable Frequency
drive is provided to the belt conveyor so that speed of feeding can be control easily
3. Drag chain Conveyor-drag chain conveyor is proved to carry the briquets and feed to
the boiler furnace via pusher feeder. Pusher Feeder is used to push the briquettes to boiler
4.PUSHER FEDDER- It is hydraulic device used to push the briquettes in to the boiler
5.Boiler Furnace- it is closed chamber having pulsating grate bar. pulsating grate bar are
mounted on movable shaft it moved to forward and Revered direction. on its top side water
tube structure is connected in ‘C’ Shape
6.Wet Ash Conveyor-After Complete Combustion of fuel ash is produced so this ash is
removed with the help of wet ash conveyor. it is long chain conveyor carrying ash from the
boiler so that it can be transferred to and collected in the tractor.
7.Forced Draft Fan (FD):-
1.Primary blower -Primary blower is provided to provide the air supply to boiler furnace
for proper combustion of fuel. It is provided to supply air from the bottom of pulsating grate
bar. Speed of FD fan is control depending upon the feeding rate of fuel
2 Secondary Blower-Secondary blower is provided to supply air on top side of pulsating
grate bar for proper combustion of fuel. variable frequency drive is also provided to
8.Boiler Drum- Boiler drum contain smoke tube water is there outside of tube and smoke
or flue gases after combustion of fuel flows through smoke tube and passed to the
economiser. Water level should be maintained always 90 % of boiler drum level and gauge
level should be 50% of total gauge glass. Air vent is also connected to boiler drum (steam
9.ID Fan (Induced draft fan)-There are two major Reason of ID fan
1.To provide Proper path for flue gases
2.To Maintain Negative Draft Pressure for Boiler Furnace which is -1.07 bar
10. Grates Bar-Pulsating grate bar are used in boiler furnace. Reciprocating motion is
provided with the help of hydraulic cylinder. This are mounted on shaft total 850 Grates bar
are used for agrowaste boiler grates bar made from cast iron
11. Air Compressor – Air Compressor is provided for pneumatic operation of valve.
Constant pressure required up-to 5 kg/cm2
12.Bag Filter -Bag Filter is provided for removing of ash particle from smoke and it
collected in the bag filter.
13.Safety valve – Total three safety valve are provided in boiler.2 valve are provided on
the top of boiler drum.
Safety valve are operated due to following reason
1. Uneven loading
3.Non-Utilisation of steam
Setting of Safety valve -First operated at pressure of 10 kg/cm2 and other is operated at
pressure of 10.25 kg/cm2
For operation of safety valve -When pressure is greater than or equal to 7.9 kg/cm2
of briquettes is stopped. If still Pressure rises than at 8.0 kg/cm2 grates bar supply is cutoff.
Now still Pressure Rises to 9.2 kg/cm2 FD fan gets trip and if it continues to rise then safety
valve operated at pressure of 10.25 kg/cm2
14.Air Vent-Air vent is connected to Boiler steam drum. The main reason of air vent is to
remove unnecessary gases from drum to reduce hammering effect in steam line. Air vent is
open only at the starting of boiler to remove unnecessary gases from steam drum. After steam
pressure reach 1 kg/cm2 pressure air vent is closed.
15.Economiser -it is an efficiency improvement device .it is connected after boiler drum
smoke after boiler drum is pass via Economiser. economiser has horizontal water tube and
smoke is passed over water tube due to this high temperature of smoke, temperature of water
increases which improves efficiency of boiler.
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written by Dattakumar