Bio-ethanol production to be blended with gasoline: Improvements in energy use by adsorption

Batch adsorption experiments were conducted to examine the liquid-phase adsorption of ethanol from ethanol-water solutions. Experiments performed established the kinetic and equilibrium behaviour of the various adsorbents in solution. The experiments with the ZSM-5 adsorbents indicate that the silica to alumina ratio had little effect on the ethanol-water separation at low ethanol concentrations. In general, ZSM-5 adsorbents were outperformed by the activated carbon adsorbents, which showed higher adsorption capacities. The capacity of activated carbon adsorbents correlated strongly with cumulative pore volume and Brunauer, Emmet and Teller (BET) surface area. Particle size was found to be the most influential factor in the ethanol uptake rate. The large pellets showed sluggish kinetics when compared to their powdered counterparts. When considering kinetic performance and adsorption capacity XTRUSORB A754 and M-30 activated carbon show the most potential for the selective adsorption of ethanol. The adsorbent screening performed herein applies to the energy efficient production of bio-ethanol via adsorption. Copyright (C) 2007 John Wiley & Sons, Ltd.