Ethanol enrichment from ethanol-water mixtures using high frequency ultrasonic atomization.

The influence of high frequency ultrasound on the enrichment of ethanol from ethanol-water mixtures was investigated. Experiments performed in a continuous enrichment system showed that the generated atomized mist was at a higher ethanol concentration than the feed and the enrichment ratio was higher than the vapor liquid equilibrium curve for ethanol-water above 40 mol%. Well-controlled experiments were performed to analyze the effect of physical parameters; temperature, carrier gas flow and collection height on the enrichment. Droplet size measurements of the atomized mist and visualization of the oscillating fountain jet formed during sonication were made to understand the separation mechanism.

Experimental quantification of cavitation yield revisited: focus on high frequency ultrasound reactors.

Acoustic cavitation plays an important role in enhancing the reaction rate of chemical processes in sonochemical systems. However, quantification of cavitation intensity in sonochemical systems is generally limited to low frequency systems. In this study, an empirical determination of cavitation yield in high frequency ultrasound systems was performed by measuring the amount of iodine liberated from the oxidation of potassium iodide (KI) solution at 1.7 and 2.4 MHz. Experiments for determining cavitation were carried out at various solute (KI) concentrations under constant temperature, obtained by direct cooling of the solution and variable temperature conditions, in the absence of external cooling. Cavitation yield measurements, reported in this work, extend previously reported results and lend credence to the two step reaction pathway in high frequency systems. Additionally, the concentration of KI and temperature affect the cavitation yield of a system such that the iodine production is proportional to both conditions. It is proposed that direct cooling of sonicated KI solution may be advantageous for optimization of cavitation intensity in high frequency sonochemical reactors.