Biofuel Production by Dehydration of Ethanol-Water mixture Using Biobased Adsorbents

Bioethanol is considered to be the most optimistic biofuel. Hydrated ethanol with more than 2% (v/v) of water is not completely miscible with gasoline, so complete dehydration of ethanol is required. Distillation alone cannot concentrate ethanol beyond its azeotropic point so various other methods are used to concentrate ethanol to completely anhydrous state in short span of 93-99.80% (w/w) ethanol. Among the separation methods, adsorption process is a simple and economical alternative. The potential of new Biobased adsorbents was assessed in separation of ethanol-water mixture. Biobased adsorbents such as bleached banana stem pulp, sodium hydroxide promoted soyabean meal and potato starch based adsorbents were used in this study. The water concentration in the feed solution was varied from 5% to 18% (weight basis). A glass adsorption column with an inside diameter of 1.54 cm was used to generate breakthrough curves to determine the effectiveness of the adsorbents. Heating jacket was provided to maintain the packed-column at constant temperature. In addition maximum water uptake and surface area of adsorbents were examined. Dehydration of ethanol vapour achieved is due to an interaction between free hydroxyl group of starch and the water molecules.