Dehydration of Ethanol using Pressure Swing Adsorption

Abstract

With the development of adsorption processes and the invention of molecular sieves, the pressure swing adsorption (PSA) process completely replaced the azeotropic and extractive distillation routes for ethanol dehydration due to performance, cost, and environmental reasons. The PSA is now the technology of choice for the ethanol dehydration for both small and large plants. In the ethanol PSA process, the water is removed with appropriately sized molecular sieve adsorbent. The adsorption of ethanol on 3A zeolite in the ethanol dehydration studies is usually neglected. Currently, two- and three-bed PSA ethanol dehydration processes are common in the industry. PSA technology is the preferred and industrially established method for the separation of water-ethanol mixtures for ethanol production. Adsorption technologies present an attractive solution to the separation of the final biorefinery products due to flexibility in the choice of adsorbents, operating conditions, process design, and cycles.