Fuels, Chemicals and Metals from Bioprocesses

4842693

APPARATUS FOR REMOVING WATER FROM ETHANOL

Alfred Wheldon, Essex, United Kingdom as- signed to The Distillers Company PLC

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

4845033

PROCESS FOR A CONTINUOUS FERMENTATIVE PRODUCTION

OF LOW ALIPHATIC ALCOHOLS OR ORGANIC SOLVENTS

Uwe Tegtmeier, Braunschweig, Federal Republic Of Germany assigned to Starcosa GmbH

Low aliphatic alcohols or organic solvents, espe- cially ethanol are continuously produced by fer- mentation from sugar containing nutrient substrates. The process includes two fermenta- tion steps or stages in which the substrate is sub- jected to the effects of microorganisms such as yeast. The first fermentation stage has a volume of 10 to 20% of that of the second fermentation stage. By adjusting the environmental conditions in each stage a large cell growth with a small por- tion of the total supplied substrate quantities takes place in the first activation stage and a high product formation rate is achieved with a con- siderably larger portion of the entire supplied substrate quantity in the second production stage. A partial outflow stream from the first stage is microfiltered and the permeate as well as the unfiltered outlet flow of the first stage, is directed into the second stage. The outlet flow of the second stage is microfiltered and the concen- trate is partly discharged as a product output stream and partly returned to the second stage. The transfer flow and return flow streams and the discharge of the permeate and the product streams from the second stage are adjusted so that, for dwell times of the cell mass of up to two hours in the first stage and up to 15 hours in the second stage, an average cell age of 40 to 100 hours is achieved with a corresponding high yield output.

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