Application of desiccant technology for concentrating liquid foods - Experimental investigation

A single tube, stainless steel, liquid desiccant falling film evaporator was built and tested with the calcium chloride solution as the liquid desiccant to concentrate liquid foods. Experiments were conducted in the above setup with sugar solutions as the liquid food. To minimize water vapor mass transfer resistance, non-condensibles were removed from the system by a vacuum pump. No steam was used to drive this evaporator. The liquid food was heated to about 48°C when the ambient temperature was 40°C. The single tube double falling film evaporator was tested to determine the effect of desiccant concentration, temperature, and flow rate on the evaporation rate. The effect of liquid food concentration, temperature, and flow rate on evaporation rate was also studied. An uncertainty and error analysis for the experimental data was performed. It was demonstrated that liquid desiccants could provide enough energy, through heat of absorption, to evaporate a liquid food in a falling film evaporator with vapor transfer lines.