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TYPES OF EVAPORATORS USED IN INDUSTRY
Evaporation:
Evaporation can be defined as the process where liquid is transformed into a gaseous state.
Evaporation can occur only when water is available. Evaporation requires that the humidity
of the atmosphere is less than the evaporating surface. Kinetic energy is the collective
motion of water molecules in the water. The kinetic energy of the molecules measures the
water temperature. Molecules have the highest kinetic energy. So, it can break the hydrogen
bonds and escape the water surface. Reducing the water temperature, average kinetic energy
is reduced.
Types of Evaporators:
In most cases it is essential that the product be subject to minimal thermal degradation
during the evaporation process, requiring that temperature and time exposure must be
minimized. This and other requirements brought on by the physical characteristics of the
processed product have resulted in the development of a large range of different evaporator
types. Additional demands for energy efficiency and minimized environmental impact have
driven development toward very innovative plant configurations and equipment design.
Different types of evaporators are used in the food industry including batch-type, natural
circulation, rising-film, falling-film, rising/falling-film, and agitated thin-film evaporators. Heat
and mass balances are used in calculations to design single- and multiple-effect evaporators.
Forced Circulation Evaporators:
Forced circulation evaporators consist of tubular heat exchangers for concentrating a feed. Forced
circulation evaporator is deployed in cases where there is a high chance of feed or product liquor
slating or scaling, or when the feed has high viscosity and the thermal and flow properties of the
process liquor are poor, rendering forced circulation necessary. In the forced circulation evaporator
mechanism, the feed is pumped at high velocity through the tubes to ensure high heat transfer
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coefficient. Forced circulation evaporator working is best suited for crystallization of slurries and
other solutions.
