Review on technologies to separate and purify ethyl alcohol from dilute aqueous solutions

Abstract

Ethyl alcohol (ethanol) is viewed upon as a fuel additive or even as an alternative fuel. Fermentation is used to produce dilute (<20 mass%) ethanol. This is needed to be concentrated to almost anhydrous, fuel grade ethanol (>99.5 mass%). The technologies used for concentration from dilute grade to fuel grade ethanol are summarized in this review. Thus, extraction; distillation; use of membranes; adsorption and some miscellaneous methods are discussed in detail. For each technique, the inlet and outlet concentrations; merits and demerits and scope for future work are indicated. Hybrid separations are discussed. In addition to technical feasibility, economic viability of the techniques is also discussed. A brief discussion on current industrial practice is also presented.

Selective direct conversion of aqueous ethanol into butadiene via rational design of multifunctional catalysts

“…[16][17][18][19][20] The aqueous ethanol purification process requires higher energy consumption because it can form an azeotropic mixture solution. 21,22 Therefore, it is very important to directly synthesize BD from cheaper aqueous ethanol instead of expensive high-purity ethanol. More interestingly, the production technology of 80% aqueous ethanol has been realized.…”