study of different types of boilers & accessories.

1. Presented By
V . Vamshi Kiran Goud
Roll No. : 13p61a0381
SEMINAR ON

2. CONTENT:
 Classification of boilers
 Fire tube boiler
 Water tube boiler
 Boiler accessories
 Essential of a good boilers
 Boiler efficiency
 Selection of boiler

3. steam generator:
A steam generator or boiler is usually a closed vessel made of steel. Its
function is to transfer the heat produced by the combustion of fuel to water and
ultimately to generate steam.
 open vessels, generating steam at atmospheric pressure are not considered to be
boiler.
The steam produced may be supplied to
• power generation
• heating
 space heating
hot water supply
• industrial processes
 sugar mills
chemical industries
INTRODUCTION

4. Classification of Boilers
Relative position of hot gas and water
• Fire tube boiler
Hot gasses pass through the tubes that are surrounded by water. Horizontal
return tubular, vertical tubular, Lancashire, Cochran, Cornish, locomotive fire box,
scotch marine etc.
• Water tube boiler
The tubes contain water and the hot gases flow outside Babcock and
Wilcox, sterling boiler Lamont boiler Wilcox, boiler, la-boiler, Benson boiler and
Loffler boiler.

5. CLASSIFICATION OF BOILERS
 Method of firing
• Internally fired boiler
• Lancashire, Locomotive, and Scotch
• Externally fired boiler
• Babcock and Wilcox
 Pressure of steam
• High pressure (>80 kg/cm2)
• Babcock and Wilcox Lamont etc
• Low pressure (<80 kg/cm2)
• Cochran, Cornish, Lancashire and
Locomotive
 According to the axis of shaft
• Vertical tubular
• Horizontal tubular
 Method of circulation of water
• Natural circulation
• Forced circulation
 Nature of service to be performed
• Land boilers
• Portable boiler
• Mobile boilers
 Heat source
• Combustion of solid, liquid, or gas
• Electrical or nuclear energy
• Hot waste gases of other chemical
reactions

6. Fire Tube Boilers
A fire tube boiler is a type of boiler in which hot gases / flue gases (products of
combustion) from a fire (heat source) pass through one or more tubes running
through a sealed container of water. The heat energy from the gases passes
through the sides of the tubes by thermal conduction, heating the water and
ultimately creating steam. A fire-tube boiler is sometimes called a "smoke-tube
boiler" or "shell boiler"
or sometimes just "fire pipe".
Types of Fire Tube Boiler
• Cochran boiler,
• Lancashire boiler,
• Scotch marine boiler,
• Locomotive boiler

7. • Vertical
• Multi tubular
• Internally fired
• Natural circulation
• Favorable in small Plants
• Coal or oil burnt
Cochran Boiler
•It is a multi-tubular vertical fire tube boiler having a number of horizontal fire tubes.
This is the modification of a simple vertical boiler where the heating surface has been
increased by means of a number of fire tubes.
•It is very compact and requires minimum floor area.
Any type of fuel can be used with this boiler.
•Well suited for small capacity requirements

8. Locomotive Boiler
Locomotive boiler is a horizontal fire tube type mobile boiler. The main requirement of
this boiler is that it should produce steam at a very high rate. Therefore, this boiler requires
a large amount of heating surface and large grate area to burn coal at a rapid rate
• Horizontal
• Multi-tubular
• Natural circulation
• Internally fired
• Fire tube
• Portable

9. Water Tube Boiler
A water tube boiler is a type of boiler in which water circulates in tubes heated externally
by the hot gases / flue gases. Water tube boilers are used for high-pressure boilers. Fuel is
burned inside the furnace, creating hot gas which heats
up water in the steam generating tubes.
Types of water tube boiler
•Babcock & Wilcox boiler,
•Sterling boiler etc.

10. Water Tube Boiler
Babcock & Wilcox boiler
The longitudinal drum boiler is the
generally accepted standard of Babcock
& Wilcox construction. The cross drum
boiler, though originally designed to
meet certain conditions of headroom, has
become popular for numerous classes of
work where low headroom is not a
requirement which must be met

11. Comparison between Water Tube and Fire Tube Boilers
S no. Particulars Fire tube boilers Water tube boilers
1. Mode of firing Internally fired Externally fired
2. Rate of steam production lower Higher
3. construction Difficult Simple
4. transportation Difficult Simple
5. Treatment of water Not so necessary More necessary
6. Operating pressure Limited to 16 bar Under high pressure as 100
bar
7. Floor area More floor area Less floor area
8. Shell diameter Large for same power Small same power
9. explosion Less More
10. Risk of bursting lesser More risk

12. Boiler Mountings
Mountings are required for proper and safe functioning of the boiler which are
generally mounted over the boiler shell.
• Pressure Gauge. This indicates the
pressure of the steam in the boiler.
•Steam Stop Valve:
It regulates the flow of steam supply outside.
Feed Check Valve: The high pressure feed
water is supplied to the boiler through this
valve. This valve opens towards the boiler only
and feeds the water to the boiler.

13. Fusible Plug: A fusible plug operates as a
safety valve when dangerous temperatures,
rather than dangerous pressures, are reached in
a closed vessel.
FEED PUMP :A pump that supplies water to a
boiler
SAFETY VALVE: A spring loaded valve that
automatically opens when pressure attains the
valve setting. Used to prevent excessive
pressure from building up in a boiler.

14. Boiler Accessories
Accessories are used for efficient running of the boiler
• Super heater
• Economizer
• Air preheated

15. Super heater
A super heater is a device used to convert saturated steam or wet steam into superheated
steam or dry steam. It is used in power stations. Super heaters are used in steam engines
or in processes, such as steam reforming. There are three types of super heaters: radiant,
convection, and separately fired

16. Economizer
A common application of economizers in steam power plants is to capture the waste heat
from boiler stack gases (flue gas) and transfer it to the boiler feed water. This raises the
temperature of the boiler feed water, lowering the needed energy input, in turn reducing
the firing rates needed for the rated boiler output

17. Fig.: An Air Preheater
Air Preheater
An air pre heater (APH) is a general term used to describe any device designed to
heat air before another process (for example, combustion in a boiler) with the primary
objective of increasing the thermal efficiency of the process.

18. Essential of a good boilers
1. The boiler should be capable of generating steam at the required
pressure and of the required quality quickly and with minimum fuel
consumption.
2. The initial cost, installation cost and the maintenance cost of the boiler
should not be too high.
3. The boiler should be light in weight, should need the least amount of
brick work construction and should occupy small floor area.
4. The boiler should meet the fluctuating demands or steam supply
without being overheated
5. The different parts of the boiler should be easily approachable for
repairs.
6. There should be no deposition of mud and other foreign particles on the
heated surfaces
7. The boiler should conform to the safety regulations as laid down in the
"Boilers Act"

19. Boiler Efficiency
Efficiency of a boiler may be defined as the ratio of heat utilized for
the generation of steam to heat supplied due to the burning of fuel.
Boiler efficiency,
ms be the mass of steam evaporated in a given time
mf be the mass of fuel burnt at the same time
HV be the heating value of fuel per unit mass
h be the enthalpy per unit mass of steam
h0 be the enthalpy of feed water
ms (h-ho )
mf*HVEnergy utilize
Energy supplied
=η =