Evaporation is a unit operation that eliminates water from a liquid food. If the liquid contains dissolved solids, the concentrated solution can become saturated or oversaturated, with solid crystals deposition.
As fruit juices contain many substances that can be damaged if submitted to high temperatures during relatively long periods, evaporation under vacuum seems to be the logical answer to this problem. When vacuum evaporation is carried out, the boiling point is lowered, and so thermal degradation is minimized.
A falling film evaporator is essentially a shell and tube heat exchanger. Steam condensing on the shell side provides the latent heat that allows the evaporation of a mass of water from the solution flowing in the tube side. Water vapor and concentrated juice, in thermodynamic equilibrium, are then separated. This process can be accomplished in one evaporation body, so the boiling concentrated solution is withdrawn from the unit for further processing and the vapor is condensed in a separated condenser. Such equipment is named ‘‘single effect evaporator’’
Evaporation is a unit operation that eliminates water from a liquid food. If the liquid contains dissolved solids, the concentrated solution can become saturated or oversaturated, with solid crystals deposition. As fruit juices contain many substances that can be damaged if submitted to high temperatures during relatively long periods, evaporation under vacuum seems to be the logical answer to this problem. When vacuum evaporation is carried out, the boiling point is lowered, and so thermal degradation is minimized. A falling film evaporator is essentially a shell and tube heat exchanger. Steam condensing on the shell side provides the latent heat that allows the evaporation of a mass of water from the solution flowing in the tube side. Water vapor and concentrated juice, in thermodynamic equilibrium, are then separated. This process can be accomplished in one evaporation body, so the boiling concentrated solution is withdrawn from the unit for further processing and the vapor is condensed in a separated condenser. Such equipment is named ‘‘single effect evaporator’’
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