摘要 |
<p>For continuous production of ethanol by fermentation, fermenting liquor is fed directly from a fermentor to a simple evaporator unit where a vacuum is maintained and where the liquor is separated into a first vapor flow enriched in ethanol, which is processed to the desired ethanol quality, and a yeast-containing bottom flow. Of the latter flow, part is recirculated to the fermentor while the rest is separated into a yeast concentrate flow, which is recirculated to the fermentor, and a yeast-free flow which is fed to a stripping unit. The second vapor flow, enriched in ethanol, which is thus obtained from the stripping unit can be fed to the simple evaporator unit directly or indirectly. The method is especially advantageous if the substrate is made by enzymatic break-down of cellulose or starch, as the enzymes in this case are not subjected to excessive temperatures but can be recovered.</p> |