DISTILLATION PROCESS FOR BIO-ETHANOL FUEL SUBSTITUTABILITY: EFFICIENCIES AND INTERACTION COEFFICIENTS PREDICTION Adepoju A. O. 1* , Taiwo E.A. 2 , Akinwale Y.O. 1 , Ogundari I.O. 1 and Ogunkanbi D.A. 1 1 National Centre for Technology Management, Ile-Ife, Osun State, Nigeria. 2 Department of Chemical Engineering, Obafemi Awolowo University, Nigeria. (*Corresponding author’s mail: adepojudeyemi@gmail.com) Abstract Globally, the world attention has drifted toward environmental sustainable development of their countries. This has called for several measures to reduce the emissions generated into the atmosphere. One of such is the blending of ethanol and gasoline for the use of motor vehicles. The blend of both mixtures is known to improve the octane index. But the problem of recovery of ethanol from the fermentation broth involves distillation of the dilute aqueous alcohol to its azeotrope. This is the basis for the study in addition to generating parameter of interaction coefficients through multiple regressions for use in physical property prediction models at various temperatures. We investigated the process packed distillation column by comparing the efficiency results of conventional packing system (the high and low voidage packing) and the modification of the column to accommodate multiple packing (combinations of both low and high voidage packing). The results showed that efficiencies of the combinations are better than that of the conventional high voidage packing but slightly lower compared to the conventional low-voidage packing. We conclude by suggesting that firm processes involving the use of distillation techniques can be modified to accommodate combination of multiple packing for optimum efficiency. This invariably makes the firm that use this approach more efficient and profitable. 1. Introduction During the production of ethanol, large quantities of water are produced with the ethanol. The fermented effluent typically has an ethanol concentration of approximately 10 percent by weight (Tracy and Clifford, 2005). Anhydrous ethanol is widely used in chemical industry as powerful solvent and as raw material or intermediate in chemical synthesis of esters, organic and cyclic compound chains, detergents, paints, cosmetics, aerosols, perfumes, medicine and food, among others (Rejl et al., 2006). Besides, ethanol and gasoline mixtures can be used as fuels, reducing environmental contamination and improving octane index (Meirelles et al., 1992). Several processes for ethanol dehydration include heterogeneous azeotropic distillation, which uses different solvents such as benzene, pentane and cyclohexane; extractive distillation with solvents and salts as separating agents (Fu, 2004a,b); adsorption with molecular sieves and processes that include the use of pervaporation membranes (Ulrich and Pavel, 1988; Pinto et al., 2000). All these processes have had industrial application but some are no longer in use due to the high operating costs, operative problems and high energy consumption. Meanwhile, distillation process is the most widely applied separation technology. Likewise, it is an important process for the foreseeable future because there is simply no industrially viable alternative around (Olujic et al., 2003). Despite many challenges from other technologies distillation improves and from time to time breakthroughs are made which move this technology to a higher level of sophistication. Distillation is a column-type separation process involving the partial condensation of vapour mixture, carried out to effect the separation of the more volatile component from the less volatile component in the initial