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US 7,732,173 B2Granted
Ethanol recovery process
AssigneeMembrane Technology and Research, Inc.
InventorsAnurag P. Mairal, Alvin Ng, Richard W. Baker, Ivy Huang, Jennifer Ly
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Abstract
A process for producing and recovering light alcohols, particularly ethanol, alcohol mixtures containing ethanol, and ABE mixtures (alcohol mixtures containing acetone, butanol and ethanol), using a combination of steps including fermentation, first membrane separation, dephlegmation and dehydration by second membrane separation.
Claims39
A process for producing a light alcohol, comprising the following steps:
- (a) fermenting a sugar to form a fermentation broth comprising the alcohol and water;
- (b) performing a first membrane separation step, comprising:
- (i) providing a first membrane having a first feed side and a first permeate side;
- (ii) passing at least a portion of the fermentation broth as a first feed stream across the first feed side under first conditions that provide a first driving force for transmembrane permeation;
- (iii) withdrawing from the first feed side a residue stream depleted in the alcohol compared with the first feed stream;
- (iv) withdrawing from the first permeate side a first permeate stream enriched in the alcohol compared with the first feed stream;
- (c) performing a dephlegmation step, comprising:
- (i) providing a dephlegmator adapted for partial condensation of a gas stream by providing countercurrent flow between the rising gas stream and a falling condensate stream;
- (ii) passing at least a portion of the first permeate stream into the dephlegmator as the gas stream;
- (iii) withdrawing from the dephlegmator an overhead stream enriched in the alcohol compared with the gas stream;
- (iv) withdrawing from the dephlegmator a condensate stream depleted in the alcohol compared with the gas stream;
- (d) performing a second membrane separation step comprising:
- (i) providing a second membrane having a second feed side and a second permeate side;
- (ii) passing at least a portion of the overhead stream across the second feed side under conditions that provide a second driving force for transmembrane permeation;
- (iii) withdrawing from the second feed side an alcohol product stream enriched in the alcohol compared with the overhead stream;
- (iv) withdrawing from the second permeate side a second permeate stream depleted in the alcohol compared with the overhead stream.
13 more elements
A process for producing ethanol, comprising the following steps:
- (a) fermenting a sugar to form a fermentation broth comprising ethanol and water;
- (b) filtering at least a portion of the fermentation broth to produce a filtrate stream;
- (c) performing a first membrane separation step, comprising:
- (i) providing a first membrane having a first feed side and a first permeate side;
- (ii) passing the filtrate stream as a liquid feed stream across the first feed side under first conditions that provide a first driving force for transmembrane permeation;
- (iii) withdrawing from the first feed side a residue stream depleted in ethanol compared with the liquid feed stream;
- (iv) withdrawing from the first permeate side a first permeate stream enriched in ethanol compared with the liquid feed stream;
- (d) performing a dephlegmation step, comprising:
- (i) providing a dephlegmator having a coolant flow side and a gas stream flow side and adapted for partial condensation of a gas stream by providing countercurrent flow between the rising gas stream and a falling condensate stream;
- (ii) passing at least a portion of the first permeate stream into the dephlegmator as the gas stream;
- (iii) flowing a coolant across the coolant flow side in heat-exchanging relationship with the gas stream;
- (iv) withdrawing from the dephlegmator an overhead stream enriched in ethanol compared with the gas stream;
- (v) withdrawing from the dephlegmator a condensate stream depleted in ethanol compared with the gas stream;
- (e) performing a second membrane separation step comprising:
- (i) providing a second membrane having a second feed side and a second permeate side;
- (ii) passing at least a portion of the overhead stream across the second feed side under conditions that provide a second driving force for transmembrane permeation;
- (iii) withdrawing from the second feed side an ethanol product stream enriched in ethanol compared with the overhead stream;
- (iv) withdrawing from the second permeate side a second permeate stream depleted in ethanol compared with the overhead stream.
15 more elements
Dependencies are inferred from the claim text.