A condenser is a two-phase flow heat exchanger in which heat is generated from the conversion of vapor into liquid (condensation) and the heat generated is removed from the system by a coolant.
Condensers may be classified into two main types:
Those in which the coolant and condensing vapor are brought into
Ø A vapor which is bubbled into a pool of liquid
Ø A liquid which is sprayed into a vapor
Ø A packed-column in which the liquid flows downwards as a film over
a packing material against the upward flow of vapor.
Those in which the coolant and condensate stream are separated by a solid surface, usually a tube wall, Condensers in which the streams are separated
In the air-cooled type, condensation occurs inside tubes with cooling provided by air blown or sucked across the tubes. Fins with large surface areas are usually provided on the air side to compensate for the low air-side heat transfer coefficients
In shell-and-tube condensers, the condensation may occur inside or outside the tubes. The orientation of the unit may be vertical or horizontal
Evaporator and condenser coils are used when the second fluid is air because of the low heat transfer coefficient on the air side.
SELECTION OF INDIRECT CONTACT
In direct contact , the two streams which are mixed together to remove the latent heat of one stream, are to be separated again .So another equipment is required so the capital and operating cost will be high so usually they are not recommended
Best choice is the indirect contact.
FOUR CONDENSER CONFIGURATION ARE POSSIBLE
1) Horizontal with condensation is shell side and cooling medium in the tubes.
2) Horizontal with condensation in tube side cooling medium in shell side.
3) Vertical with condensation in the shell.
4) Vertical with condensation in the tubes.
Horizontal shell side and vertical tube side are the most commonly used types of condensers.
SELECTION OF HORIZONTAL CONDENSER
When a condenser is employed on a distillation column, several specific factors must be taken into consideration.For the same height , horizontal condensers are more suited for the Reflux to send back by gravity. Vertical Condenser has to be elevated considerably above the column, which in many cases is very tall by itself. Maintenance and structural support may be costly , are pump is installed for the reflux to send back which is again costly Most suited choice is Horizontal Indirect contact type Condenser.
In this process we have used the normal mechanism for heat transfer in commercial condenser which film wise condensation.
Since vapor-liquid heat transfer changes usually occur at constant or really constant pressure in industry, the vaporization or condensation of a single compared normally occurs isothermally. If a mixture of vapors instead of a pure vapor is condensed at constant pressure, the change does not take place isothermally in most instances.