Fractional Freezing of Ethanol and Water Mixture

Abstract

Fractional freezing was introduced to separate a mixture that contains a volatile organic compound in this case; ethanol and water. The mixture was separated by using freezing process since both ethanol and water have different freezing points. This method is an alternative method for fractional distillation as it does not consume high amount of energy to supply heat for vaporization purpose. Besides, this method is safer to our environment as it does not liberate any harmful vapor or gases since there is no heating process involved. In this study, the performance of the process in producing high purity ethanol was evaluated based on two parameters which are stirring rate and coolant temperature. It was found that the concentration of ethanol in liquid phase increased as the stirring rate increased. The ethanol concentration has increased by 52.2% when the stirring rate was at the highest rotating speed which is 500 rpm. When the coolant temperature was decreased to -14˚C, the ethanol concentration in liquid phase increased the most by 56.5%. Thus it can be concluded that the concentration of ethanol in liquid phase increased as the coolant temperature decreased.