Behavior of Organic Impurities in Distillation Column for Bioethanol Production Plant from Waste Woods

Abstract

In the distillation process occurring in a bioethanol production plant using waste woods for ethanol concentration and for removing organic impurities, the product quality improved when pH control is applied in the reflux tank by adding NaOH and discharging fusel oil from a side stream of the distillation column. In this study, the details of the improvements were studied from the viewpoint of the vapor–liquid equilibrium (VLE) of organic impurities present in the distillation column. The relative volatilities of the impurities to ethanol were determined by using a model mixture containing 13 organic impurities found in the plant as a function of ethanol mole fraction. The distributions of the 13 organic impurities in the distillation column were determined by the Thiele Geddes method by using the measured relative volatility data. The behavior of the 13 organic impurities in the distillation column was useful to understand the quality of the product and the effect of the fusel oil discharge from a side stream. The relative volatilities of butyric acid, 1-butanol, 2-methyl-1-butanol and 2-butanol decreased by NaOH addition.