Process for recovering alcohol with energy integration
AssigneeGeorgia Tech Research Corporation
InventorDaniel W. Tedder
Life of this patent
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Abstract
A process for recovering alcohol by a continuous process employing fermentation, solvent extraction of the alcohol product, extractive distillation of the alcohol-solvent extract to provide water fraction and vacuum stripping for separation of the alcohol and regenerated solvent. The solvent is recycled. An isoparaffin is used as a solvent and this solvent can be modified with a long chain fatty acid, alcohol or fatty alcohol or long-chain esters. Alternatively, many modifiers may be used neat.
Claims32
A process of producing alcohol comprising:
- (a) feeding a sugar and water containing feed stock to a fermenter;
- (b) providing the fermenter with fermentation microorganisms and operating the fermenter continuously for converting the feed stock into a fermentation product containing alcohol, sugar and microorganisms;
- (c) preheating said fermentation product;
- (d) feeding said fermentation product to a solvent extraction column;
- (e) delivering to said solvent extraction column a solvent which is non-toxic to the fermentation microorganisms and which will dissolve and decrease the volatility of said alcohol relative to the water in said feedstock such that said water is more volatile than said alcohol in the presence of said solvent and said solvent is less volatile than either said water or said alcohol in ternary mixtures of said solvent, said water and said alcohol, said solvent is immiscible in the water in the fermentation product for liquid to liquid extraction of the alcohol for providing an alcohol-solvent extract phase and a water phase, said water phase comprising microorganisms, solids and water;
- (f) removing alcohol-solvent extract phase from said solvent extraction column and directing the alcohol-solvent extract phase to an extractive distillation dehydration unit;
- (g) removing said water phase from said solvent extraction column and returning said water phase to said fermenter;
- (h) distilling in said extractive distillation dehydration unit the bulk of the residual water from said alcohol-solvent extract phase leaving a dehydrated extract including alcohol and solvent to provide more efficient liquid/liquid extraction of the alcohol from the fermentation product in said solvent extraction column;
- (i) returning the distilled water from said extractive distillation dehydration unit to the solvent extraction column;
- (j) delivering said dehydrated extract to a vacuum stripping unit;
- (k) separating said alcohol from said solvent in said dehydrated extract in said vacuum stripping unit to produce regenerated solvent and alcohol product;
- (l) returning a portion of the regenerated solvent to said extractive distillation dehydration unit and a portion of the regenerated solvent to said solvent extraction column;
- and
- (m) discharging said alcohol product from said vacuum stripping unit.
A process for recovering alcohol from a fermentation product containing alcohol, sugar, water and microorganisms, comprising preheating said fermentation product, contacting said fermentation product countercurrently with a solvent having low microbial toxicity which is miscible with said alcohol and will decrease the volatility of said alcohol relative to said water such that the volatility of the alcohol in the presence of solvent is less than that of said water, said solvent containing a paraffin selected from the group consisting of branched and linear alkanes having C.sub.12 to C.sub.16 for providing an alcohol solvent phase and a water phase, separating the alcohol-solvent phase from the water phase, adding regenerated solvent to said alcohol-solvent phase, distilling the residual water from the alcohol-solvent phase, recycling said distilled water to the step in the process where said fermentation product is contacted with said solvent,
Dependencies are inferred from the claim text.