PRODUCTION OF ETHANOL AND RECYCLE WATER IN A CELLULOSIC FERMENTATION PROCESS

摘要

Processes for producing ethanol from fermentation systems employing cellulosic feedstocks are provided, where water is processed for recycle. The water handling portion of the process employs multi-effect evaporators where the first effect evaporator is maintained at temperatures in excess of 105° C., and the evaporation train, beer column form a heat integrated system.

主权项

1. A process for the production of ethanol and recycle water comprising:
a) providing a hydrolysate fermentation medium; b) fermenting the medium in a fermenter in the presence of a microorganism that produces ethanol to produce a beer comprising from about 6% to about 10% ethanol, water, solutes, and solids; c) providing a distillation and water handling system comprising the elements:
I) a beer column;II) a rectification column;III) a solids removal mechanism; andIV) an evaporation train comprising at least four evaporation effect equivalents; wherein each element in the system is connected to at least one other element in the system, and wherein the beer column, the rectification column, and the evaporation train form a heat integrated system; d) passing the beer into the beer column of (I) where a beer column ethanol-rich vapor stream is separated from a water stream containing solutes and solids; e) condensing the beer column ethanol-rich vapor stream forming a beer column ethanol-rich stream; f) passing the beer column ethanol-rich stream into the rectification column of (II) wherein a further ethanol-enriched rectification column vapor stream is separated from an ethanol depleted water stream; g) passing the water stream containing solutes and solids of (d) through the solids removal mechanism of (III) producing a water stream containing solutes with solids substantially removed; h) passing the water stream containing solutes with solids substantially removed of (g) through the evaporation train of (IV) producing an evaporate comprising water containing high-volatility solutes and a syrup comprising low-volatility solutes, wherein a first effect evaporator of the evaporator train of (IV) is run at a temperature that is greater than 105° C. for at least about 10 days without fouling of heat exchange surfaces; and i) treating the evaporate of (h) to substantially remove the high-volatility solutes producing recycle water; wherein ethanol-enriched vapor is produced and water is processed for recycle.