Perspectives on Intensification of Ethanol-Water Separation Process in a High Frequency Ultrasound System

Abstract

Application of high frequency ultrasound for generating a fine droplet mist has been recently applied for fine chemical manufacturing, pharmaceutical production, cleaning and agitation/mixing. A recent development is the enrichment of alcohols from miscible alcohol–water mixtures using ultrasonic atomization. In this work, the effect of high frequency ultrasonic atomization at 1.6 MHz on the separation of ethanol from ethanol–water feed mixtures has been studied. Experiments for evaluating this novel separation process were conducted in a constant volume separation system. Well-controlled experiments were performed to analyze the separation of ethanol–water feed mixture at different temperatures (between 283 and 313 K). An interesting aspect of the separation process is the concentration of ethanol above the vapor–liquid equilibrium curve above 40 mol% ethanol feed concentration. It was found that the enrichment ratio was not affected by feed solution temperature. However, mist generation rate increased with increasing feed temperature. An understanding of the role of the ultrasonic jet formed at the surface of the feed solution combined with the separation characteristics of ethanol–water feed mixtures has been discussed here and the dependence of the process on acoustic cavitation has been elucidated.