Alcohol Recovery and Carbon Dioxide Purification in Alcohol Plants Using Semipermeable Membranes. Final Technical Report, September 1, 1981-August 31, 1982

摘要

The fermentation of sugars to ethanol produces carbon dioxide gas, which can carry appreciable quantities of alcohol vapor from the system. This project examined the use of commercially available membranes to separate a gaseous mixture into alcohol rich and carbon dioxide rich streams. The performance of silicone and cellulose acetate membranes in separating alcohol-carbon dioxide mixtures was studied with a single stage test cell. The cellulose acetate membrane passed the alcohol vapor preferentially and gave a better separation than the silicone membranes. The permeabilities of alcohol and carbon dioxide for the cellulose acetate membrane were used to design a continuous membrane column, which makes it possible to achieve a high degree of separation with membranes giving only modest enrichment in a single stage. For a 25 x 10 exp 6 gal/yr alcohol plant, a computer simulation indicated that 200 continuous membrane columns with areas of 93 m exp 2 each would be needed to recover about 75% of the alcohol and to produce a byproduct stream containing 99.5% carbon dioxide. (ERA citation 08:019989)