# US 8,569,552 B2 · Recovery of butanol from a mixture of butanol, water, and an organic extractant

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- Number: US 8,569,552 B2
- Document ID: US8569552B2
- Status: Granted
- Kind: B2
- Application number: 13/611,087
- Filed: 2012-09-12
- Published: 2013-01-03
- Granted: 2013-10-29
- Earliest claimed: 2009-11-23
- Assignees: Butamax Advanced Biofuels LLC
- Applicants: Michael Charles Grady; William D Parten; Bruce M Vrana; Yihui Tom Xu; Joseph J Zaher
- Inventors: Michael Charles Grady; William D Parten; Bruce M Vrana; Yihui Tom Xu; Joseph J Zaher
- Web page: https://patentgrep.com/patent/US8569552B2

## CPC

- C12P 7/16: Butanols
- C07C 29/86: by liquid-liquid treatment
- Y02E 50/10: Biofuels, e.g. bio-diesel
- Y02P 20/141: Feedstock
- C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)}
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A process for recovering butanol from a mixture comprising a water-immiscible organic extractant, water, butanol, and optionally a non-condensable gas, is provided. The butanol is selected from 1-butanol, 2-butanol, isobutanol, and mixtures thereof. An overhead stream from a first distillation column is condensed to recover a mixed condensate. An entrainer is added to at least one appropriate process stream or vessel such that the mixed condensate comprises sufficient entrainer to provide phase separation of the organic and the aqueous phases to provide for recovery of the butanol.

## Claims

### Claim 1

A process comprising the steps:
a) introducing a feed comprising:
(i) a water-immiscible organic extractant;
(ii) water;
(iii) at least one isomer of butanol;
(iv) optionally a non-condensable gas;
(v) ethanol; and
(vi) optionally fermentation by-products
into a first distillation column,
wherein the first distillation column comprises a stripping section and optionally a rectifying section at an introduction point above the stripping section, the first distillation column having an operating temperature, T1 and an operating pressure P1 in the stripping section;
wherein T1 and P1 are selected to produce a first bottoms stream and a first vaporous overhead stream, the first bottoms stream comprising the water-immiscible organic extractant, butanol, and ethanol and being substantially free of water, and the first vaporous overhead stream comprising water, butanol, ethanol, optionally the extractant, and optionally the non-condensable gas;
b) introducing a water-immiscible organic entrainer to at least one appropriate process stream or vessel;
c) condensing the first vaporous overhead stream to produce a gas phase and recover a mixed condensate, wherein the mixed condensate comprises:
(i) an organic phase comprising butanol, ethanol, entrainer, and water; and
(ii) an aqueous phase comprising water, butanol, ethanol; and
wherein the mixed condensate comprises sufficient entrainer to provide phase separation of the organic and the aqueous phases;
d) introducing at least a portion of the organic phase to the first distillation column; and
e) introducing at least a portion of the first bottoms stream into a second distillation column having at least a stripping section and optionally a rectifying section and operating the second distillation column to produce a second bottoms stream comprising the extractant, and a second vaporous overhead stream comprising butanol and ethanol.

### Claim 2 (depends on 1)

The process of claim 1 wherein the extractant is selected such that it (A) preferentially extracts butanol over water and (B) is separable from butanol by distillation; and the entrainer is selected such that it (C) has a higher vapor pressure than butanol and (D) is separable from butanol by distillation.

### Claim 3 (depends on 1)

The process of claim 1, wherein the appropriate process stream or vessel is selected from the feed stream, the first vaporous overhead stream, the mixed condensate stream, the first distillation column, the decanter, and combinations thereof.

### Claim 4 (depends on 1)

The process of claim 1, further comprising the step of introducing at least a portion of the aqueous phase to a fermentation vessel.

### Claim 5 (depends on 1)

The process of claim 1, further comprising the step of withdrawing the bottoms stream from the second distillation column and introducing at least a portion of the withdrawn bottoms stream into a fermentation vessel.

### Claim 6 (depends on 5)

The process of claim 5, further comprising the step of introducing at least a portion of the aqueous phase to a fermentation vessel.

### Claim 7 (depends on 6)

The process of claim 6, further comprising the step of combining at least a portion of the withdrawn bottoms stream and at least a portion of the aqueous phase before introducing the combined stream to a fermentation vessel.

### Claim 8 (depends on 1)

The process of claim 1, further comprising partially condensing the gas phase to recover at least a portion of the entrainer and optionally introducing the recovered entrainer to the mixed condensate.

### Claim 9 (depends on 8)

The process of claim 8, wherein non-condensable gas is present in the feed, the gas phase further comprises the non-condensable gas, and the process further comprises the step of purging at least a portion of the gas phase comprising the non-condensable gas from the process.

### Claim 10 (depends on 9)

The process of claim 9, wherein the non-condensable gas comprises carbon dioxide, nitrogen, hydrogen, noble gases, or mixtures.

### Claim 11 (depends on 1)

The process of claim 1, the process further comprises the steps of:
g) introducing the second vaporous overhead stream into a third distillation column having at least a stripping section,
h) operating the third distillation column to produce a third bottoms stream comprising butanol and a third vaporous overhead stream comprising the entrainer; and
i) optionally, introducing the third vaporous overhead stream to the mixed condensate.

### Claim 12 (depends on 1)

The process of claim 1, wherein the feed comprises an organic phase obtained from an extractive fermentation.

### Claim 13 (depends on 1)

The process of claim 1, wherein the butanol concentration in the feed is from about 0.1 weight percent to about 40 weight percent, based on the weight of the feed.

### Claim 14 (depends on 1)

The process of claim 1, wherein the entrainer comprises at least one hydrocarbon.

### Claim 15 (depends on 14)

The process of claim 14, wherein the entrainer comprises at least one hydrocarbon selected from the group consisting of pentane, hexane, hexene, cyclohexane, benzene, toluene, and xylene.

### Claim 16 (depends on 1)

The process of claim 1, wherein the extractant comprises at least one solvent selected from the group consisting of C7 to C22 fatty alcohols, C7 to C22 fatty acids, esters of C7 to C22 fatty acids, C7 to C22 fatty aldehydes, C7 to C22 fatty amides, and mixtures thereof.

### Claim 17 (depends on 16)

The process of claim 16, wherein the extractant comprises at least one solvent selected from the group consisting of C12 to C22 fatty alcohols, C12 to C22 fatty acids, esters of C12 to C22 fatty acids, C12 to C22 fatty aldehydes, C12 to C22 fatty amides, and mixtures thereof.

### Claim 18 (depends on 16)

The process of claim 16, wherein the butanol comprises 1-butanol.

### Claim 19 (depends on 16)

The process of claim 16, wherein the butanol comprises 2-butanol.

### Claim 20 (depends on 16)

The process of claim 16, wherein the butanol comprises isobutanol.

### Claim 21 (depends on 1)

The process of claim 1 wherein the butanol in the feed introduced into a first distillation column is produced by fermentation of corn or sugar cane.

### Claim 22 (depends on 1)

The process of claim 1 further comprising a process to process heat exchange between the feed introduced to the first distillation column and the first bottoms stream.

### Claim 23 (depends on 1)

The process of claim 1, wherein the fermentation by-products comprise volatile fermentation by-products.

### Claim 24 (depends on 23)

The process of claim 23, wherein the organic phase comprises the volatile fermentation by-products.

### Claim 25 (depends on 24)

The process of claim 24, wherein at least a portion of the organic phase is purged to remove the volatile fermentation by-products.

### Claim 26 (depends on 1)

The process of claim 1, wherein the feed is obtained from a fermentation vessel or an extractor.