Adsorptive separation of ethanol blended gasoline on zeolites

Abstract

Various types of zeolites were evaluated for the adsorptive separation of ethanol and gasoline in ethanol blended gasoline. Mixed solution of ethanol and n-heptane was used as a model fuel. Adsorption selectivities of zeolites for ethanol and n-heptane were measured by a pulse testing method at 80 °C. These properties were dependent on the framework structures, exchangeable cations and Si/Al atomic ratios of zeolites. The adsorption capacities of zeolites for ethanol and n-heptane were evaluated by a continuous flow adsorption testing method at 80 °C. Zeolites with the FAU type structure (Na-Y and H-Y) showed higher adsorption capacities compared to the other types of zeolites. Adsorption strength of ethanol on zeolites was evaluated by a temperature programmed desorption method. Ethanol molecules adsorbed on Na-Y and H-Y were desorbed by heat treatment at around 300 °C, but ethanol adsorbed on H-Y was partially dehydrated because of zeolite acidity.