ABSTRACT
Evaporators are used in food processing to reduce the moist-
ure content of a dilute liquid product (1-10% total solids) to
a more concentrated and still pumpable liquid product (up to
80% total solids). The main goal is to improve the microbial
stability and the shelf life of these products. In addition, the
costs to store and transport the concentrated material is
considerably reduced in comparison to the raw dilute liquid
product. Since evaporation involves the boiling of excess
moisture, most evaporation equipment consists of a heat
exchanger, and a separation vessel to separate the concen-
trated liquid product from the vapor. The efficiency of the
evaporation process and product quality is highly dependent
on the type of evaporator. The additional major goal of the
evaporation process is to minimize the thermal degradation
of the resulting product. This requires that the time of
exposure of the food product to elevated temperature be
minimized. Techniques such as 1) rapid rate of heat transfer;
2) use of vacuum resulting in lower operation temperature;
3) efficient liquid-vapor separation; and 4) efficient energy
use and recovery have been employed to achieve this impor-
tant goal. Other issues that have arisen in the last few years
in evaporation technology include environmental impact,
energy efficiency, and waste utilization.
