Abstract
Recently it has been reported that ethanol is concentrated from ethanol aqueous solution by using ultrasonic atomization. Compared with distillation, the concentration by ultrasonic atomization is not accompanied with phase change. However, the study on ultrasonic atomization concentration from a standpoint of reactor engineering is rarely performed. An atomization vessel was cylindrical and transparent. The sample to be concentrated was ethanol aqueous solution. Air was used as a carrier gas. The initial concentration of alcohol, the solution temperature, the velocity and the location of inlet and outlet of carrier gas were changed, and the alcohol concentration in atomized liquid and atomization rate were measured. As atomization temperature become lower, the alcohol concentration in atomized liquid becomes higher and the atomization rate becomes lower. This is because the vaporization rate from liquid surface becomes lower. With decreasing velocity of the carrier gas, alcohol concentration in atomized liquid increases and the atomization rate decreases. This is because at the low gas velocity, relatively large liquid droplets, which consist of solution with low concentration of alcohol, are difficult to be carried to the exterior of vessel. In order to prevent from emission of large liquid droplets, the demister was attached atomization vessel. At fixed atomization rate, the alcohol concentration in atomized liquid for the atomization vessel with demister is higher than to that for the atomization vessel without demister.
