| 摘要 |
The present invention provides in the production of ethanol, the method of establishing and maintaining continuous fermentation under steady-state conditions in a fermentor comprised in a continuous process circuit by establishing and maintaining in the fermentor an amount of active yeast cells to achieve a certain ethanol productivity, continuously charging into said circuit a feed flow comprising fermentable as well as non-fermentable substance, said feed flow being dimensioned for supply of fermentable substance in accordance with said ethanol productivity to maintain a concentration of fermentable substance in the fermentor less than 2.5% by weight, releasing from the fermentor carbon dioxide formed during the fermentation, withdrawing continuously from said fermentor an outlet stream of fermentation liquor at a flow rate to maintain in said outlet stream an ethanol concentration less than about 7% by weight, continuously separating said stream of fermentation liquor into at least one continuous yeast concentrate flow and a continuous essentially yeast-free flow, returning said yeast concentrate flow to the fermentor, continuously separating said yeast-free flow, in an ethanol separation step, into a flow enriched in ethanol and a residue flow, continuously discharging said ethanol-enriched flow, continuously discharging part of said residue flow, and continuously returning to the fermentor the remaining part of said residue flow, the method also comprising pasteurization at a temperature in the range of 60-100.degree.C of the substance recirculated from said ethanol separation step to the fermentor.
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