Experimental Study On Adsorption Capability For Ethanol Dehydration Using Cornmeal As Adsorbent

Ethanol of 99.5%wt can be obtained by selective adsorption of water on biomass. As the cornmeal that has adsorbed the water don't need to be regenerated but is just sent for fermentation to produce ethanol, significant energy saving could be expected for the ethanol production especially for fuel ethanol production.This dissertation aims at experimental investigation on the selective adsorption of water for ethanol dehydration with cornmeal as adsorbent. A bench test scale apparatus with a column of 25mm inner diameter and packed with a bed of cornmeal of 900mm height was designed to perform the experiments. The feed is a vapor mixture of ethanol and water. After the stage of adsorption, nitrogen gas is sent to pass through the bed to desorb the adsorbate, which is collected by the cold trap cooled by liquid nitrogen on the top of fixed bed. The effects of superficial velocity, bed temperature, bed depth and concentration of feed on the capability and selectivity of adsorption were observed by performing experiments for different operation conditions. The isotherm of water adsorption on cornmeal was also plotted.The equilibrium adsorption capacity of water on cornmeal was calculated based on a mass-transfer zone model and the calculated results were checked with the experimental results. And the relationship of the height of the fixed-bed and the time for reaching breakthrough point at constant temperature, vapor superficial velocity and vapor concentration was correlated by integrating the breakthrough curve based on the mass-transfer zone model.