Various types of heat transfer equipments are used in the chemical industry depending upon the applications involved (i.e., based on the service required), but their common task is to transfer heat from a hot fluid to a cold fluid. The heat exchange equipments involve heat energy transfer either by conduction-convection or by radiation mode. In the chemical industry, shell and tube type heat exchangers constitute the bulk of unfired heat transfer equipment.
A heat exchanger is a device used to effect the process of heat exchange between two fluids that are at different temperatures. Recuperators (also called as surface heat exchangers) are heat exchangers in which the fluids are separated by a metal wall, e.g., steam boilers, heater, condensers, etc.
Based upon the function, heat transfer equipments can be referred as cooler, heater, condenser, etc.
Cooler :
It is a heat exchange equipment used to cool a process fluid (gas or liquid) by means of water or atmospheric air. It involves the removal of sensible heat from the process fluid (stream).
Condenser :
It is a heat exchange equipment used to condense a vapour or a mixture of vapours (in the presence or absence of noncondensable gas). It involves the removal of latent heat with the help of a suitable cooling medium, e.g., cooling tower water or chilled water.
Chiller :
It is a heat exchange equipment employed to cool a process fluid (stream) to a temperature below that can be obtained by using water as a cooling medium. It employs a refrigerant such as ammonia or freon as a cooling medium.
Exchanger :
It is a heat exchange equipment that is used to exchange the heat between hot and cold process streams/fluids.
Heater :
It is a heat exchange equipment which imparts sensible heat to a process fluid (stream). Condensing steam or dowtherm may be used as a heating medium.
It heats a process stream by condensing steam.
Reboiler :
It is a heat exchange equipment, used to meet the latent heat requirement at the bottom of a distillation column. The heating medium may be either steam or a hot process fluid.
Vaporiser :
It is a heat exchange equipment (unfired) which vaporises part of the liquid.
Waste - heat boiler :
It is a heat exchange equipment employed for the production of steam using a hot process stream or a hot gas or a hot liquid stream produced in a chemical reaction as a heating medium.
Evaporator :
It is a heat exchange equipment employed for the concentration of a solution by evaporation of water. Condensing steam is used as a heating medium.