Sweet potato bioethanol purification using glycerol

Abstract

Bioethanol is obtained from biomass sources (maize, sugar cane and beet) and sweet potato has been presented as a promising alternative for this purpose. Anhydrous ethanol can be obtained by extractive distillation of hydrated alcohol with chemical agents and it is usable for biodiesel production, from which a glycerol byproduct is obtained. The present work evaluates the use of glycerol as dehydrating agent to obtain anhydrous ethanol. With this objective, two grades of sweet potato bioethanol, 88.0 and 94.0°GL respectively, were used in the experiments with three volumetric ratios of 0.25, 0.50 and 0.75 V/V of glycerol/bioethanol and the results compared with those obtained using ethylene glycol under the same conditions. The highest ethanol grade obtained was 96.9°GL using glycerol and 96.6°GL using ethylene glycol, both using a 0.75 V/V ratio. The purity of bioethanol increased with the amount of drag agent used, whereas the yield decreased. (c) 2018 Taylor & Francis Group, London, UK.