Steam Drum, Super Heater, Economizer, Air preheater- SAMRIDDHA SHIL

1. SAMRIDDHA SHIL- STEAM DRUM, SUPER HEATER,
ECONOMIZER, AIR PREHEATER(APH)
SAMRIDDHA SHIL
MECHANICAL ENGINEER
STEAM DRUM, SUPER HEATER,
ECONOMIZER,
AIR PREHEATER(APH)

2. SAMRIDDHA SHIL- STEAM DRUM, SUPER HEATER,
ECONOMIZER, AIR PREHEATER(APH)
STEAM DRUM:It is a standard feature of water-tube
boiler. It is a reservoir of water/steam at the top end of
the water tubes. The drum stores the steam generated
in the water tubes. It is used on recirculating boilers
that operate at subcritical pressures. The primary
purpose of the steam drum is to separate the saturated
steam from the steam water mixture that leaves the
heat transfer surfaces and enters the drum. The steam-
free water is recirculated within the boiler with the
incoming feedwater for further steam generation. The
saturated steam is removed from the drum through a
series of outlet nozzles,where the steam is used as is or
flows to a superheater for further heating.(By
definition,saturated steam is pure steam that is at the
temperature that corresponds to the boiling
temperature at a particular pressure. For
example,saturated steam at a pessure of 500 psi,has a
temperature of 4670
F).

3. SAMRIDDHA SHIL- STEAM DRUM, SUPER HEATER,
ECONOMIZER, AIR PREHEATER(APH)
SUPER HEATER: A superheater is a device used to
convert saturated steam or wet steam into dry steam.
Steam which has been superheated is logically known
as superheated steam.
Non-superheated steam is called saturated steam or
wet steam.
1. TYPES OF SUPERHEATER:
a) Radiant superheater: It is located directly in the
combustion chamber. Platen/Panel superheater is the
type of radiant superheater which is located in the
second pass of the boiler.
b) Convection superheater: It is located in the path of
the hot gases. Convective type superhheaters are
placed in the second pass of the boiler and these are
also called low temperature superheater.
2.SUPERHEATING SYSTEM: Superheaters in large
capacity boilers are of both convective type superheater
and radiant type superheater.
The convective type superheaters are placed in the
second pass of the boiler and these are also called low

4. SAMRIDDHA SHIL- STEAM DRUM, SUPER HEATER,
ECONOMIZER, AIR PREHEATER(APH)
temperature superheater. generally about a 40 to 60
degree centigrade pick up takes place on the steam side
in this superheater. The steam from this moves to a
radiant type superheater is called the panel or platen
superheater and about a 70 to 100 degree centigrade
pick up takes place there. This is followed by the final
superheater and remaining required temperature is
picked up here.
3.INJECTION TYPE DESUPERHEATING: In almost all large
capacity boilers there are two injection points provided.
The first desuperheater is placed between low
temperature superheater and the platen/panel
superheater. The second one is placed the platen/panel
and final superheater. The control is done mostly by the
desuperheater and second one is more for fine
tuning,as the response time for the first is long.
In both the cases the feed water is tapped at an
appropriate point and injected as fine spray through in
the steam pipe of desuperheater.

5. SAMRIDDHA SHIL- STEAM DRUM, SUPER HEATER,
ECONOMIZER, AIR PREHEATER(APH)
The mechanical design aspect includes liners so that the
temperature differential is not directly felt on the
pressure part side of the desuperheater.
ECONOMIZER: In simple term, an economizer is a heat
exchanger which is a mechanical device intented to
reduce energy conjumption or to perform useful
function as preheating a fluid.
AIR PREHEATER(APH): An air preheater 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
efficiency of the process.
Purpose of APH: the purpose of APH 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.