Surface
Condenser | Difference Between Jet Condenser and Surface Condenser
In this article described about the water requirement calculation for
condenser, difference between direct contact and surface condenser &
Types of surface condenser and its application
Condenser Water Requirement Calculation | Types of Surface
Condensers
In sugar Industry Condensers and cooling
systems are used in boiling process to create vacuum in pans and evaporators.
The principle of condenser is based on the
transmission of heat content in the vapour to the cooling or injection water.
The quantity of the cooling water necessary for condensation of vapour is found
by equating the heat given up by the vapour in condensing to the heat absorbed
by the cold water.
Where
W = weight of the cooling water in kg/kg of
vapour to be condensed
To = Temperature of the hot water leaving the condenser
Ti = Temperature of the cold water entering the condenser
Main Classification of Condensers
The steam condensers may be broadly
classified into the following two types, depending upon the way in which the
steam is condensed.
1. Direct Contact condenser (or) Jet
condenser (or) Mixing type condenser
2. Surface condensers ( or) non-mixing type condensers.
Direct Contact or Jet Condensers:
Direct contact condensers are commonly used
for condensing the vapour in evaporators and vacuum pans. In this condensers,
where the cooling water comes into direct contact with the vapour to be
condensed.
For complete information regarding the this
type of condenser please go through the below link
Types of Direct Contact Condenser System with
design criteria for vacuum creations and condensation of vapour
Surface Condenser:
A surface
condenser has a great advantage over the direct contact
condensers, as the condensate does not mix with the cooling water. As a result
of this, whole condensate can be reused in the system.
This type of condenser is essential in ships,
which can carry only a limited of fresh water for the boilers. It is also
widely used in land installations, where inferior water is available or the
better quality of water for feed is to be used economically.
Surface condenser consists of a horizontal
cylindrical vessel packed with tubes, through which the cooling water flows,
the ends of the condenser are cut off by vertical perforated type plates into
which water tubes are fixed.
It consists of longitudinal section with
number of passes. The water passes through the tubes and steam passes through
shell side of the condenser.
Steam Condenser in
thermal power plants
A steam condensers is a closed vessel into
which the steam is exhausted and condensed after doing work in on engine
cylinder or turbine. A steam condenser has the following two objects.
1 . The primary object is to maintain a low
pressure (below atmospheric pressure) so as to obtain the maximum possible
energy from steam and thus to secure a high efficiency.
2. The secondary object is to supply pure feed water to the hot well, from
where it is pumped back to the boiler.
Types of Surface Condensers:
The surface
condensers may be further classified on the basis of the
direction of the condensate, the arrangement of tubing system and the position
of the extraction pump into following four types.
1. Down flow surface condenser.
2. Central flow surface condenser.
3. Regenerative surface condenser.
4. Evaporator condenser
Down flow condenser
In down flow condenser the steam enters at
the top and flow downwards over the tubes due to force of gravity as well as
suction of the extraction pump fitted at the bottom. The condensate is
collected at the bottom and then pumped by the extraction pump. The dry air
pump suction pipe, which is provided near the bottom, is covered by baffle so
as to prevent the condensed steam into it as shown in figure. As the steam flow
perpendicular to the direction of flow of cooling water (inside the tubes) this
is called cross surface condenser.
Central flow surface condenser:
In central flow surface condenser, the
exhaust steam enters at the top and flow downward. The suction pipe of the air
is placed in the center of the tube nest. This causes the steam to flow
radically inwards over the tubes towards the suction pipe. The condensate is
collected at the bottom and the pumped by extraction pump. The central flow
surface condenser is an improvement over the down flow type as the steam is
directed radially inwards by a volute casting around the tube nest. It tubes
gives an access to the whole periphery of the tubes.
Evaporative condenser:
The steam to be condensed enters at the top
of a series of pipes outside of which is a film of cold water. At the same
time, a current of air circulates over the film, causing rapid evaporation of
some of the cooling water. As a result of this the steam circulating inside the
pipe is condensed. The remaining cooling water is collected at an increased
temperature and is reused, its original temperature is restored by the addition
of the requisite quantity of cold water.
This condenser consists of filled piping, which is bent back and forwards and
in a vertical plane.
Regenerative surface
condensers:
In regenerative surface condenser, the
condensate is heated by a regenerative method. The condenser after the tubes is
passed through the exhaust from the engine (or) turbine.
Difference between
surface condenser and jet condenser
|
S.NO |
Surface Condenser |
Jet or Direct Contact Condenser |
|
1 |
Steam and
Cooling water are not mixed up. |
Cooling
water and steam are mixed up |
|
2 |
More
suitable for high capacity plants. |
Less
suitable for high capacity plants. |
|
3 |
Condensate
is reused. |
Condensate
is wasted |
|
4 |
It
requires large quantity of circulating water. |
It
requires less quantity of circulating water |
|
5 |
The
condensing plant is costly and complicated. |
Condensing
plant is economical and simple |
|
6 |
Its
maintenance cost is high. |
Its
maintenance cost is low. |
|
7 |
Less
power is required for air pump. |
More
power is required for air pump. |
|
8 |
Less
power is required for waste pumping |
High
power is required for water pumping |
No comments:
Post a Comment