Different parameters affecting the efficiency of evaporators in the food industry

Evaporation is a mechanism in which heat and mass transfer happens simultaneously, leading to vapor separation from a solution. In the food industry, the principal purposes of evaporation consist of mass and volume decrease, preservation by reducing water activity, and obtaining the desired consistency. The rate of evaporation depends mainly on the temperature of the liquid, the temperature of the surroundings, the pressure above the liquid, surface area, and rate of heat transfer to the product. Evaporator design is related to various factors like physical characteristics of the raw and final product, processing requirements, capacity, and efficiency of the evaporator. In the evaporation process, energy represents the most important operation cost item. Evaporator design and modification research aims to achieve economic efficiency, reducing power consumption without quality loss of the final product. This chapter describes parameters affecting the efficiency of evaporators such as properties of feed (viscosity, concentration ratio, feed flow rate, relative volatility, noncondensibles, heat transfer characteristics, and boiling point elevation), foaming, pressure and temperature of the system, fouling, vapor velocity in the evaporator, design and operating conditions of the evaporator, heat transfer medium, and heat and mass transfer.