초록 ▼

A method and apparatus for removing water from a liquid mixture of water and ethanol contacts it with liquid carbon dioxide so that the ethanol is preferentially transferred into solution, dries the solution using an adsorbent, and then recovers dry ethanol by distilling off the carbon dioxide. This

A method and apparatus for removing water from a liquid mixture of water and ethanol contacts it with liquid carbon dioxide so that the ethanol is preferentially transferred into solution, dries the solution using an adsorbent, and then recovers dry ethanol by distilling off the carbon dioxide. This process is particularly energy efficient especially when it includes a fermentation process to generate the ethanol and uses the carbon dioxide generated during the fermentation as the source of liquid carbon dioxide. In this case the method and apparatus provide an additional product of dry carbon dioxide.

대표청구항 ▼

A method of removing water from a mixture containing water and ethanol comprising the steps of: (a) contacting a liquid ethanol water mixture with liquid carbon dioxide as a contaction step whereby the ethanol is preferentially transferred from said liquid ethanol water mixture into solution with sa

A method of removing water from a mixture containing water and ethanol comprising the steps of: (a) contacting a liquid ethanol water mixture with liquid carbon dioxide as a contaction step whereby the ethanol is preferentially transferred from said liquid ethanol water mixture into solution with said liquid carbon dioxide to increase the ratio of ethanol to water in said liquid carbon dioxide and provide a first fraction comprising ethanol/water and a second fraction comprising ethanol/water/carbon dioxide; (b) drying said second fraction comprising ethanol/water/carbon dioxide resulting from step (a) to produce a dry mixture comprising ethanol and carbon dioxide by a process including contacting said combined mixture with an absorbent which adsorbs substantially all of said water from it; (c) supplying heat to said dry mixture comprising ethanol and carbon dioxide to cause volatilization of a fraction rich in carbon dioxide and removing said carbon dioxide rich fraction to thereby increase the proportion of ethanol in the remaining dry mixture; (d) scrubbing the carbon dioxide rich vapour evolved in step (c) with said dry mixture to remove substantially all of said ethanol from the carbon dioxide rich vapour evolved in step (c) thereby producing a carbon dioxide fraction; (e) condensing said carbon dioxide fraction to reform liquid carbon dioxide and recycling said reformed liquid carbon dioxide to contaction step (a); (f) continuing said recycling of the reformed liquid carbon dioxide to increase the concentration of ethanol and so produce a concentrated dry mixture; (g) feeding said concentrated dry mixture containing ethanol and carbon dioxide to a distillation column having a cooled top and a heated bottom and recovering substantially water free ethanol from said bottom of said distillation column.