Patent ID: 8088958

Claim:
A method for recovery of at least one alcohol from a dilute aqueous alcohol feed stream, said method comprising: a) providing a source of a dilute aqueous alcohol feed stream; wherein the dilute aqueous alcohol feed stream comprises at least one alcohol; b) substantially removing any solids from the dilute aqueous alcohol feed stream to form a feed stream substantially devoid of solids; c) circulating the feed stream substantially devoid of solids through a liquid-liquid extraction system comprising multiple equilibrium stages; wherein the feed stream substantially devoid of solids is contacted with a solvent that has an stronger affinity for the at least one alcohol than for water; and wherein the solvent is substantially immiscible with the feed stream substantially devoid of solids for a sufficient time to transfer at least a portion of the at least one alcohol into the solvent; d) recovering a raffinate phase substantially depleted in the at least one alcohol and an extract phase substantially enriched in the at least one alcohol; e) passing the extract phase to a recovery system in which the extract phase is subjected to microwave radiation; wherein the microwave radiation substantially heats the at least one alcohol but not the solvent to form a volatilized product comprising a substantially pure alcohol; f) recovering the volatilized product; and g) recycling the solvent to the liquid-liquid extraction system after the at least one alcohol has been volatilized.