Boiler accessories and its component

1. BOILER ACCESSORIES
ABHI

2. What is a Boiler?
A boiler is a closed vessel in which
fluid is heated. The fluid does not
necessarily boil. The heated or
vaporized fluid exits the boiler for
use in various processes or heating
applications, including water
heating, central heating, boiler-
based power generation, cooking,
and sanitation
Boilers are used to
produce steam. The
generation part of a
steam system uses
a boiler to add energy
to a feedwater supply to
generate steam. The
energy is released from
the combustion of fossil
fuels or from process
waste heat.

3. BOILER ACCESSORIES
 The accessories are mounted on the boiler to increase its efficiency.
These units are optional on an efficient boiler. With addition of
accessories on the boiler, the plant efficiency also increases.
 The following accessories are normally used on a modern boiler:
(i) Economizer
(ii) Super heater
(iii) Air pre heater
(iv) Feed water pump
(v) Steam injector

4. ECONOMIZER
 An economizer is a heat exchanger, used for heating the feed water before it
enters the boiler.
 The economizer recovers some of waste heat of hot flue gases going to
chimney. It helps in improving the boiler efficiency. It is placed in the path of
flue gases at the rear end of the boiler just before air pre-heater
 The feed water is pumped to the bottom header and this water is carried to the
top header through a number of vertical tubes. Hot flue gases are allowed to
pass over the external surface of the tubes. The feed water which flows upward
in the tubes is thus heated by the flue gases. This pre-heated water is supplied
to the boiler.

5. SUPER HEATER
 It is a heat exchanger in which heat of combustion products is used to dry the
wet steam, pressure remains constant, its volume and temperature increase.
Basically, a super heater consists of a set of small diameter U tubes in which
steam flows and takes up the heat from hot flue gases.
 A superheater is a vital part of the a boiler system that is used to increase the
overall efficiency of a thermal power plant. More specifically, it is a device which
converts wet steam (saturated steam) into dry steam as dry steam contains
more thermal energy. Dry steam is also less likely to condense within the
engine cylinders or the casing of a steam turbine

6. AIR PRE HEATER
 Air Pre-heaters are basically heat-exchangers installed in the exit flus gas duct
of the boiler. The purpose of the air preheater is to recover the heat from the
boiler flue gas which increases the thermal efficiency of the boiler by reducing
the useful heat lost in the flue gas.
 The purpose of the air preheater is to recover the heat from the boiler flue gas
which increases the thermal efficiency of the boiler by reducing the
useful heat lost in the flue gas.

7. FEED WATER PUMP
 It is used to feed the water at a high pressure against the high pressure of
steam already existing inside the boiler.
 They serve to feed a steam generator such as a boiler or a nuclear reactor with
a quantity of feed water corresponding to the quantity of steam emitted. Today,
all boiler feed pumps are centrifugal pumps.

8. Steam injector
 A steam injector lifts and forces the feed water into the boiler. It is usually
used for vertical and locomotive boilers and can be accommodated in small
space. It is less costly. It does not have any moving parts thus operation is
salient