Technical-economic viability of ethanol dehydration by azeotropic distillation with gasoline to obtain an ethanol + gasoline mixture

Abstract

Over the past few decades, developed countries have focused their attention on the curbing of greenhouse gas (GHG) emissions. Transport is responsible for a high percentage of GHG emissions, and for this reason, it is necessary to use alternative fuels that would not contribute in increasing these emissions. Biofuels such as bioethanol have therefore been suggested as a potential alternative to achieve these reductions. Although this can readily be obtained by fermentation of sugar beet, wheat and corn, the disadvantage is that with distillation, it is not possible to completely remove the water content in the stream coming from the fermentation process. The aim of all commercial ethanol dehydration processes is to obtain pure ethanol. However, a likely alternative could be based on the production of a “dry” mixture of ethanol + hydrocarbon by azeotropic distillation using the hydrocarbon as entrainer. In this way, the resulting mixture could be directly employed as gasoline.