USOO8968522B2

(12) United States Patent (10) Patent No.: US 8,968,522 B2 Xu et al. (45) Date of Patent: *Mar. 3, 2015

(54) RECOVERY OF BUTANOL ISOMERS FROM (58) Field of Classification Search A MIXTURE OF BUTANOL ISOMERS, USPC ...... 203/4, 14, 18, 50, 51, 57, 60, 61, 62, WATER, AND AN ORGANIC EXTRACTANT 203/63, 78,80; 568/913, 918 See application file for complete search history. (75) Inventors: Yihui Tom Xu, Newark, DE (US); William D. Parten, Wilmington, DE (56) References Cited (US) U.S. PATENT DOCUMENTS (73) Assignee: Butamax Advanced Biofuels LLC, 4,428,798 A * 1/1984 Zudkevitch et al...... 203/18 Wilmington, DE (US) 4,511.437 A * 4, 1985 Hecket al...... 2O3/19 (*) Notice: Subject to any disclaimer, the term of this (Continued) patent is extended or adjusted under 35 U.S.C. 154(b) by 261 days. FOREIGN PATENT DOCUMENTS This patent is Subject to a terminal dis WO 2008143704 11, 2008 claimer. WO WO 2009/O13160 1, 2009 OTHER PUBLICATIONS (21) Appl. No.: 12/834,915 Roffler, et al., “Extractive fermentation of acetone and butanol: pro (22) Filed: Jul. 13, 2010 cess design and economic evaluation'. Biotechnology Progress, vol. 3, No. 3, 1987, pp. 131-140. (65) Prior Publication Data (Continued) US 2011 FO162953 A1 Jul. 7, 2011 Primary Examiner — Virginia Manoharan Related U.S. Application Data (57) ABSTRACT (60) Provisional application No. 61/225,659, filed on Jul. 15, 2009. A process for recovering butanol from a mixture of a water immiscible organic extractant, water, butanol, and optionally (51) Int. C. a noncondensable gas, is provided. The butanol is selected BOID 3/40 (2006.01) from 1-butanol, isobutanol, and mixtures thereof An over CD7C29/84 (2006.01) head stream from a first distillation column is decanted into two liquid phases. The wet butanol phase is returned to the (Continued) first distillation column as reflux. A bottom stream from the (52) U.S. C. first distillation column is refined in a second distillation CPC ...... BOID3/143 (2013.01); C07C29/84 column to obtain a second overhead stream and a second (2013.01); B0ID3/002 (2013.01); C07C29/80 bottoms stream. The extractant may be C7 to C fatty alco (2013.01); C07C29/86 (2013.01) hols, C, to C fatty acids, esters of C, to C fatty acids, C, to USPC ...... 203/50; 203/51; 203/60; 203/61; C fatty aldehydes, and mixtures thereof. 203/62; 203/63; 203/78; 203/80; 203/14: 203/18: 203/57:568/913:568/916 14 Claims, 2 Drawing Sheets

US 8,968,522 B2 Page 2

(51) Int. Cl. plasmids from Lactobacillus pantarum'. Applied and Environmental CD7C29/86 (2006.01) Microbiology, vol. 71, No. 3, Mar. 2005, p. 1223-1230. C07C3L/2 (2006.01) Ezei et al., "Bioproduction of butanol from biomass: from genes to BOID 3/4 (2006.01) bioreactors'. Current Opinion in Biotechnology, London, GB, vol. BOID 3/00 (2006.01) 18, No. 3, Jun. 8, 2007, pp. 220-227. C07C 29/80 (2006.01) Griffith et al., “1-butanol extraction with vegetable-oil fatty-acid esters', Jan. 1, 1983, Developments in Industrial Microbiology, (56) References Cited Elsevier Science BV. Amsterdam, NL, pp. 795-800. U.S. Appl. No. 12/758,870, filed Apr. 13, 2010. U.S. PATENT DOCUMENTS International Search Report and Written Opinion in corresponding PCT/US2010/042092 mailed Feb. 16, 2010. 4,636.284 A * 1/1987 English et al...... 203/18 Oudshoorn, et al., Assessment of Options for Selective 1-Butanol 4,784,668 A * 1 1/1988 Breitschaft et al...... 106,3148 Recovery from Aqueous Solution, Ind. Eng. Chem. Res. 48:7325 4,865,973 A 9/1989 Kollerup et al. T336 2009. 4.978.430 A * 12/1990 Nakagawa et al...... 203/14 Groot, et al., Technologies for Butanol Recovery Integrated with 5,985,100 A * 1 1/1999 Aron et al...... 203,74 Fermentations, Process Biochem. 27:61-75, 1992. 7,128,814 B2 * 10/2006 Beckmann et al...... 2O3/2 Roffler, et al., In situ Extractive Fermentation of Acetone and 7,311,813 B2 12/2007 Reyneke et al. 2007/00929.57 A1 4/2007 Donaldson et al. Butanol, Bitechnol. Bioeng. 31:135-143, 1988. 2008/O132741 A1* 6/2008 D'Amore et al...... 568,840 Schugerl, Integrated Processing of Biotechnology Products, 2009/0030537 A1 1, 2009 Harle Biotechnol. Adv. 18:581-599, 2000. 2009/0305370 A1 12/2009 Grady et al. Shi, et al., Performance Evaluation of Acetone-Butanol Continuous 2010, 0221802 A1 9/2010 Grady et al. Flash Extractive Fermentation Process, Bioprocess Biosyst. Eng. 2011/OO97773 A1 4/2011 Grady et al. 27:175-183, 2005. Roffler, et al., In-situ recovery ofbutanol during fermentation, Part 1: OTHER PUBLICATIONS Batch extractive fermentation, Bioprocess Engineer. 2:1-12, 1987. Evans, et al., Enhancement of Butanol Formation by Clostridium Vane, “Separation technologies for the recovery and dehydration of acetobutylicum in the Presence of Decanol-Oleyl Alcohol Mixed alcohols from fermentation broths”, Biofuels, Bioproducts & Extractants, Appl. Environ. Microbiol. 54:1662-1667, 1988. Biorefining, John Wiley & Sons, Ltd., GB, vol. 2, No. 6, Nov. 1, 2008, pp. 553-588 Van Kranenburg et al., “Functional anaylsis of three * cited by examiner U.S. Patent Mar. 3, 2015 Sheet 1 of 2 US 8,968,522 B2

U.S. Patent Mar. 3, 2015 Sheet 2 of 2 US 8,968,522 B2

US 8,968,522 B2 1. 2 RECOVERY OF BUTANOL SOMERS FROM In one aspect, the present invention is a process comprising A MIXTURE OF BUTANOL ISOMERS, the steps: WATER, AND AN ORGANIC EXTRACTANT a) introducing a feed comprising: (i) a water-immiscible organic extractant, CROSS REFERENCE TO RELATED (ii) water, APPLICATIONS (iii) at least one isomer ofbutanol, and (iv) optionally a non-condensable gas This application claims the benefit of priority to U.S. Pro into a first distillation column, wherein the first distillation visional Patent Application 61/225,659, filed Jul. 15, 2009, 10 column comprises a stripping section and optionally a recti the entirety of which is herein incorporated by reference. fying section at an introduction point above the stripping section, the first distillation column having an operating tem perature. T and an operating pressure P at a predetermined FIELD OF THE INVENTION point in the stripping section, wherein T and P are selected 15 to produce a first bottoms stream and a first vaporous over Processes for recovering butanol from a butanol-contain head stream, the first bottoms stream comprising the water ing organic phase obtained from an extractive fermentation immiscible organic extractant and butanol and being Substan process are provided. Specifically, processes for separating tially free of water, and the first vaporous overhead stream butanol from a mixture comprising butanol, water, a water comprising water, butanol, and the optional non-condensable immiscible organic extractant, and optionally a non-condens gaS able gas, are provided. b) condensing the first vaporous overhead stream to pro duce a gas phase and recover a first mixed condensate, BACKGROUND OF THE INVENTION wherein the first mixed condensate comprises (i) a butanol phase comprising butanol, less than about Butanol is an important industrial chemical with a variety 25 30 wt % water; and of applications, such as use as a fuel additive, as a blend (ii) an aqueous phase comprising water and less than component to diesel fuel, as a feedstock chemical in the about 10 wt % of butanol: plastics industry, and as a foodgrade extractant in the food and c) introducing at least a portion of the aqueous phase to the flavor industry. Each year 10 to 12 billion pounds of butanol first distillation column; are produced by petrochemical means. As the projected 30 d) introducing a first portion of the butanol phase into a demand for butanol increases, interest in producing butanol Second distillation column having at least a stripping from renewable resources Such as corn, Sugar cane, or cellu section; and losic feeds by fermentation is expanding. e) introducing a first portion of the first bottoms stream into In a fermentative process to produce butanol, in situ prod 35 a second distillation column having at least a stripping uct removal advantageously reduces butanol inhibition of the section and optionally a rectifying section and operating microorganism and improves fermentation rates by control the second distillation column to produce a second bot ling butanol concentrations in the fermentation broth. Tech toms stream comprising the extractant and being Sub nologies for in situ product removal include stripping, stantially free ofbutanol, and a second vaporous over adsorption, pervaporation, membrane solvent extraction, and 40 head stream comprising butanol: liquid-liquid extraction. In liquid-liquid extraction, an extrac wherein the extractant preferentially dissolves butanol over tant is contacted with the fermentation broth to partition the water and is separable from butanol by distillation. butanol between the fermentation broth and the extractant phase. The butanol and the extractant are recovered by a BRIEF DESCRIPTION OF THE FIGURES separation process, for example by distillation. In the recov 45 ery process, the butanol can also be separated from any water, FIG. 1 illustrates one embodiment of a system useful for non-condensable gas, and/or fermentation by-products which practicing the process of the invention. may have been removed from the fermentation broth through FIG. 2 illustrates a process Schematic diagram used in use of the extractant. modeling the process of the invention. Processes for recovering butanol from the butanol-contain 50 ing extractant phase obtained by in situ product removal from a fermentation broth are sought. Economical processes for DETAILED DESCRIPTION OF THE INVENTION recovering butanol substantially free of water and of the extractant are desired. Also desired are separation processes Applicants specifically incorporate the entire contents of which are energy efficient and provide high purity butanol 55 all cited references in this disclosure. Further, when an product having little color. Butanol recovery processes which amount, concentration, or other value or parameter is given as can be run for extended periods without equipment fouling or either a range, preferred range, or a list of upper preferable repeated shutdowns are also sought. values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any 60 upper range limit or preferred value and any lower range limit SUMMARY OF THE INVENTION or preferred value, regardless of whether ranges are sepa rately disclosed. Where a range of numerical values is recited The present invention provides a process for separating a herein, unless otherwise Stated, the range is intended to butanol selected from the group consisting of 1-butanol, include the endpoints thereof, and all integers and fractions isobutanol, and mixtures thereof, from a feed comprising a 65 within the range. It is not intended that the scope of the water-immiscible organic extractant, water, the butanol, and invention be limited to the specific values recited when defin optionally a non-condensable gas. ing a range. US 8,968,522 B2 3 4 Definitions The term “fatty acid as used herein refers to a carboxylic The following definitions are used in this disclosure: acid having along, aliphatic chain of C, to C. carbonatoms, “Butanol as used herein refers with specificity to the which is either saturated or unsaturated. butanol isomers 1-butanol (1-BuOH) and/or isobutanol The term “fatty alcohol as used herein refers to an alcohol (iBuOH or I-BUOH), either individually or as mixtures having a long, aliphatic chain of C7 to C. carbon atoms, thereof. 2-Butanol and tert-butanol (1,1-dimethyl ethanol) which is either saturated or unsaturated. are specifically excluded from the present use of the term. The term “fatty aldehyde' as used herein refers to an alde “In Situ Product Removal” as used herein means the selec hyde having along, aliphatic chain of C, to C. carbonatoms, tive removal of a specific fermentation product from a bio which is either saturated or unsaturated. 10 Non-condensable gas means a gas that is not condensed at logical process Such as fermentation to control the product an operating temperature of the process described herein. concentration in the biological process. Butanol-containing extractant streams useful as a feed in "Fermentation broth' as used herein means the mixture of the processes of the invention include any organic phase water, Sugars, dissolved solids, Suspended Solids, microor obtained from an extractive fermentation wherein butanol is ganisms producing butanol, product butanol and all other 15 produced as a fermentation product. Typical butanol-contain constituents of the material held in the fermentation vessel in ing extractant streams include those produced in “dry grind' which product butanol is being made by the reaction of Sugars or “wet mill fermentation processes in which in situ product to butanol, water and carbon dioxide (CO) by the microor removal is practiced using liquid-liquid extraction of the fer ganisms present. The fermentation broth is the aqueous phase mentation broth with an organic extractant. After extraction, in biphasic fermentative extraction. From time to time, as the extractant stream typically comprises butanol, water, and used herein the term “fermentation medium may be used the extractant. The extractant stream may optionally com synonymously with “fermentation broth'. prise a non-condensable gas, which can be a gas that is inert "Fermentation vessel” as used herein means the vessel in or otherwise non-reactive with other feed components under which the fermentation reaction by which product butanol is the operating conditions of the present invention. Such gases made from sugars is carried out. The term “fermentor” may be 25 can be selected from gases in the group consisting of for used synonymously herein with “fermentation vessel. example, carbon dioxide, nitrogen, hydrogen, Noble gases The term “effective titer” as used herein, refers to the total Such as argon, or mixtures of any of these. The extractant amount of butanol produced by fermentation per liter offer stream may optionally further comprise fermentation mentation medium. The total amount ofbutanol includes: (i) by-products having sufficient solubility to partition into the the amount of butanol in the fermentation medium; (ii) the 30 extractant phase. Butanol-containing extractant streams use amount ofbutanol recovered from the organic extractant; and ful as a feed in the processes of the invention include streams (iii) the amount of butanol recovered from the gas phase, if characterized by a butanol concentration in the feed from gas stripping is used. about 0.1 weight percent to about 40 weight percent, for The term “aqueous phase titer as used herein, refers to the example from about 2 weight percent to about 40 weight concentration ofbutanol in the fermentation broth. 35 percent, for example from about 5 weight percent to about 35 "Stripping as used herein means the action of transferring weight percent, based on the weight of the feed. Depending all or part of a Volatile component from a liquid stream into a on the efficiency of the extraction, the aqueous phase titer of gaseous Stream. butanol in the fermentation broth can be, for example, from “Stripping section” as used herein means that part of the about 5 g/L to about 85g/L, or from about 10 g/L to about 40 contacting device in which the stripping operation takes 40 g/L. place. The extractant is a water-immiscible organic solvent or “Rectifying as used herein means the action of transfer solvent mixture having characteristics which render it useful ring all or part of a condensable component from a gaseous for the extraction ofbutanol from a fermentation broth. The stream into a liquid stream in order to separate and purify extractant preferentially partitions butanol from the aqueous lower boiling point components from higher boiling point 45 phase, for example by at least a 1.1:1 concentration ratio. Such components. that the concentration of butanol in the extractant phase is at “Rectifying section' as used herein means the section of least 1.1 times that in the aqueous phase when evaluated in a the distillation column above the feed point, i.e. the trays or room-temperature extraction of an aqueous solution of packing material located above the point in the column where butanol. Preferably, the extractant preferentially partitions the feed stream enters, where the rectifying operation takes 50 butanol from the aqueous phase by at leasta 2:1 concentration place. ratio. Such that the concentration ofbutanol in the extractant The term “separation” as used herein is synonymous with phase is at least two times that in the aqueous phase when “recovery and refers to removing a chemical compound evaluated in a room-temperature extraction of an aqueous from an initial mixture to obtain the compound in greater solution of butanol. To be of practical use in the butanol purity or at a higher concentration than the purity or concen 55 recovery process, the extractant is separable from butanol by tration of the compound in the initial mixture. distillation, having a boiling point at atmospheric pressure The term “water-immiscible” refers to a chemical compo which is at least about 30 degrees Celsius higher than that of nent, such as an extractant or solvent, which is incapable of the butanol to be recovered, or for example at least about 40 mixing with an aqueous Solution, Such as a fermentation degrees higher, or for example at least about 50 degrees broth, in Such a manner as to form one liquid phase. 60 higher. The term “extractant” as used herein refers to one or more The extractant comprises at least one solvent selected from organic solvents which are used to extract butanol from a the group consisting of C, to C fatty alcohols, C7 to C fatty fermentation broth. acids, esters of C, to C fatty acids, C, to C fatty aldehydes, The term “organic phase', as used herein, refers to the C, to C fatty amides and mixtures thereof. Suitable organic non-aqueous phase of a biphasic mixture obtained by con 65 extractants are further selected from the group consisting of tacting a fermentation broth with a water-immiscible organic oleylalcohol (CAS No. 143-28-2), behenylalcohol (CAS No. eXtractant. 661-19-8), cetyl alcohol (CAS No. 36653-82-4), lauryl alco US 8,968,522 B2 5 6 hol, also referred to as 1-dodecanol (CAS No. 1 12-53-8), cent water. For example, the bottoms stream 110 can com myristyl alcohol (112-72-1), stearyl alcohol (CAS No. 112 prise less than about 0.01 weight percent water. To ensure that 92-5), 1-undecanol (CAS No. 1 12-42-5), oleic acid (CAS No. the bottom stream 110 is substantially free of water, the 112-80-1), lauric acid (CAS No. 143-07-7), myristic acid amount of organic phase reflux and the reboiler boil-up rate (CAS No. 544-63-8), stearic acid (CAS No. 57-11-4), methyl can be varied. Stream 300 is condensed in a condenser 550 to myristate CAS No. 124-10-7), methyl oleate (CAS No. 112 produce a first mixed condensate stream 310 comprising a 62-9), undecanal (CAS No. 1 12-44-7), lauric aldehyde (CAS liquid. The mixed stream 310 can further comprise a non No. 1 12-54-9), 2-methylundecanal (CAS No. 110-41-8), condensable gas component if the gas was present in the feed. oleamide (CAS No. 301-02-0), linoleamide (CAS No. 3999 The condenser 550 may be of any conventional design. 01-7), palmitamide (CAS No. 629-54-9) and stearylamide 10 The mixed condensate stream 310 is introduced into a (CAS No. 124-26-5) and mixtures thereof. In some aspects, decanter 700 and allowed to separate into a gas phase option the extractant comprises oleyl alcohol. Suitable solvents are ally comprising the non-condensable gas, a liquid butanol described in U.S. Patent Application Publication No. phase, and a liquid aqueous phase. The temperature of the 2009030537 and also in U.S. application Ser. Nos. 12/759, decanter is preferably maintained at or below about 40°C. to 283 and 12/758,870 (both filed Apr. 13, 2010), all of which 15 reduce the amount ofbutanol and water being stripped out by are incorporated herein by reference. the non-condensable gas. The liquid butanol phase, the lighter These organic extractants are available commercially from liquid phase (the top liquid phase), can include about 16 to various sources, such as Sigma-Aldrich (St. Louis, Mo.), in about 30 weight percent water and may further comprise any various grades, many of which may be suitable for use in extractant which comes overhead in column 500. The fraction extractive fermentation to produce or recover butanol. Tech of extractant in the butanol phase can be minimized by use of nical grades contain a mixture of compounds, including the an optional rectification section in column 500. The liquid desired component and higher and lower fatty components. aqueous phase includes about 3 to about 10 weight percent For example, one commercially available technical grade butanol. The decanter may be of any conventional design. oleyl alcohol contains about 65% oleyl alcohol and a mixture When a non-condensable gas Such as carbon dioxide is of higher and lower fatty alcohols. 25 present in the feed, the non-condensable gas is present in The invention provides processes for separating or recov stream 300 and in stream 310. At least a portion of the gas ering butanol from a feed comprising a water-immiscible phase comprising the non-condensable gas can be purged organic extractant, water, the butanol, and optionally a non from the process, as shown in FIG. 1, in which purge stream condensable gas. Separation of the butanol from the feed is 460 comprising the non-condensable gas is shown leaving the achieved through a combination of distillation and decanta 30 decanter 700. tion. The distillation involves the use of at least two distilla From the decanter 700, the aqueous phase 480 can be tion columns. The first column, in combination with decan purged from the process, as shown in FIG. 1, in which the tation, effects a separation of water from butanol and the purge stream comprising the aqueous phase 480 is shown extractant. The cooled overhead stream from the first column leaving the decanter 700. Alternatively, at least a portion of is decanted into two liquid phases. The organic phase is 35 the aqueous phase can be introduced to a fermentation vessel returned to the first column. The second column effects a (not shown). This can provide a means to recycle some of the separation ofbutanol from the extractant under vacuum con water from the butanol recovery process back to the extractive ditions and provides a butanol stream which is Substantially fermentation process. In one embodiment, at least a portion of free of extractant. The second column also provides an extrac the aqueous phase can be combined with at least a portion of tant stream which is substantially free of water and has a 40 the bottoms stream from the second distillation column and reduced butanol content. then introduced to a fermentation vessel, as shown in FIG. 2 The processes of the invention can be understood by ref wherein the aqueous phase 48 from the decanter 70 is com erence to FIG. 1, which illustrates one embodiment of a bined in a mixer 75 with the bottoms stream 44 from the system useful for practicing the process of the invention. The second distillation column to provide combined stream 45. feed stream 100, obtained from a fermentation vessel (not 45 The butanol phase 470 from the decanter is returned to the shown) or an extractor (not shown) in a process for fermen first distillation column 500. Stream 470 would normally be tative extraction, is introduced into a first distillation column introduced as reflux to the column. Introducing stream 470 as 500, which has a stripping section and optionally a rectifying liquid reflux will Suppress extractant loss in vaporous stream section, at a feed point above the stripping section. The feed 300 of column 500. The butanol phase 470 may further com stream 100 is distilled to provide a first bottoms stream 110 50 prise Volatile fermentation byproducts such as acetaldehyde. and a first vaporous overhead stream 300 comprising water, Optionally, at least a portion of stream 470 may be purged butanol, and any non-condensable gas present in the feed. An from the process (not shown) to remove volatile fermentation operating temperature T and an operating pressure P at a byproducts from the butanol recovery process. predetermined point in the stripping section of column 500 The first bottoms stream 110 is withdrawn from column are selected so as to provide the first bottoms stream 110 55 500 and introduced into a second distillation column 800, comprising the extractant and butanol and being Substantially which has a stripping section and optionally a rectifying free of water. The distillation column 500 can be any conven section, at a feed point above the stripping section. The stream tional column having at least a feed inlet, an overhead vapor 110 is distilled to provide a second bottoms stream 420 com outlet, a bottoms stream outlet, a heating means, and a suffi prising the extractant and a second vaporous overhead stream cient number of stages to effect the separation of the water 60 400 comprising butanol. The second distillation column is from the extractant. In the case where the extractant com operated so as to provide the bottoms stream 420 substantially prises oleyl alcohol, distillation column 500 should have at free of butanol. By “substantially free of butanol it is meant least 5 stages including a re-boiler. that the bottom 420 comprises less than about one weight The first bottoms stream 110 can comprise from about 0.1 percent butanol. The second vaporous overhead stream 400 is to about 40 weight percent butanol, and can be substantially 65 substantially free of the extractant. By “substantially free of free of water. By “substantially free”, it is meant that the extractant it is meant that the overhead stream 400 comprises bottoms stream can comprise less than about 0.1 weight per less than about 0.01 weight percent extractant. The distilla US 8,968,522 B2 7 8 tion column 800 can be any conventional column having at attributes of the invention. Reference should be made to the least a feed inlet, an overhead vapor outlet, a bottoms stream appended claims, rather than to the foregoing specification, as outlet, a heating means, a stripping section, and a sufficient indicating the scope of the invention. number of stages to effect the desired separation. Column 800 The process of the invention can be demonstrated using a should have at least 6 stages a including re-boiler. Preferably, computational model of the process. Process modeling is an column 800 is operated at a pressure less than atmospheric to established methodology used by engineers to simulate com minimize the temperature of the extractant in the base of the plex chemical processes. Process modeling software per column while enabling economical and convenient conden forms many fundamental engineering calculations, for sation of the butanol overheads. example mass and energy balances, vapor/liquid equilibrium The process may further comprise introducing bottoms 10 stream 420 from the second distillation column into a fermen and reaction rate computations. The modeling of distillation tation vessel (not shown). In one embodiment, bottoms columns is particularity well established. Calculations based stream 420 may be combined with at least a portion of the on experimentally determined binary vapor/liquid equilib aqueous phase 480 from the decanter before introduction into rium and liquid/liquid equilibrium data can predict reliably a fermentation vessel, as shown in FIG. 2 wherein analogous 15 the behavior of multi-component mixtures. This capability streams 44 and 48 are combined in mixer 75 to provide the has been expanded to allow modeling of complex multi-stage, combined stream 45. multi-component distillation columns using rigorous algo A mixture of higher boiling extractants is expected to rithms like the “inside-out' algorithm developed by Joseph behave in a fundamentally similar way to a single extractant Boston of Aspentech, Inc. of Burlington, Mass. Commercial provided that the boiling point of the mixture, or the boiling modeling Software, such as Aspen Plus(R from Aspentech, point of the lowest boiling solvent of the mixture, is signifi can be used in conjunction with physical property databases, cantly higher than the boiling points of water and butanol, for such as DIPPR, available from the American Institute of example at least about 30 degrees higher. Chemical Engineers, Inc., of New York, N.Y., to develop The present processes for separating or recovering butanol accurate models and assessments of processes. provide butanol known to have an energy content similar to 25 that of gasoline and which can be blended with any fossil fuel. EXAMPLES Butanol is favored as a fuel or fuel additive as it yields only CO, and little or no SC or NC whenburned in the standard The Examples were obtained through process modeling internal combustion engine. Additionally, butanol is less cor using isobutanol as the butanol isomerandoleyl alcohol as the eXtractant. rosive than ethanol, the most preferred fuel additive to date. 30 In addition to its utility as a biofuel or fuel additive, the Similar results would be expected for the analogous cases butanol recovered according to the present processes has the where 1-butanol or a mixture of 1-butanol and isobutanol was potential of impacting hydrogen distribution problems in the selected as the butanol isomer, due to the similarity of the emerging fuel cell industry. Fuel cells today are plagued by physical property data for isobutanol and 1-butanol and the safety concerns associated with hydrogen transport and dis 35 heterogeneous nature of the azeotrope between water and tribution. Butanol can be easily reformed for its hydrogen these butanol isomers. content and can be distributed through existing gas stations in Table 1 lists typical feed compositions of the rich solvent the purity required for either fuel cells or vehicles. Further stream, obtained from extractive fermentation, entering the more, the present processes recover butanol obtained from isobutanol product recovery area. These compositions were plant derived carbon sources, avoiding the negative environ 40 used in modeling the processes of the invention. In the mental impact associated with standard petrochemical pro Examples, the term “rich solvent stream” is synonymous with cesses for butanol production. the term “feed stream” used above. One advantage of the present processes for separation or recovery of butanol is energy integration of the distillation TABLE 1 columns, which provides energy efficiency. Relative to a dis 45 Feed Compositions (in Weight Percent) of the tillation scheme in which the separation of butanol and Rich Solvent Stream from the Extractor extractant is made prior to the final separation ofbutanol and water, the present processes require less energy per unit Feed Compositions Example 1 Example 2 weight of butanol obtained. Isobutanol 11.44% 25.10% Another advantage is that the present processes provide 50 Water 6.47% 8.23% high purity butanol having little or no color. Carbon dioxide O.88% O.94% A further advantage is that the second bottoms stream Oleyl alcohol 81.21% 65.73% comprising the extractant is Substantially free of the butanol product, which contributes to high yield in the recovery pro These composition values for the rich solvent stream were cess. Being substantially free ofbutanol also enables optional 55 established by a simulation of a dry grind facility using recycling of the second bottoms stream comprising the extractive in situ product removal technology producing 50 extractant to the fermentative process. Being Substantially mM gal/year of isobutanol, and fermenter broth aqueous free ofbutanol also simplifies the stream's disposition, should phase titers of 20 and 40 g/L respectively. It was assumed that it not be recycled. the rich solvent stream was at equilibrium with the fermen Yet another advantage is that the present processes allow 60 tation broth and that the solvent flow rate was sufficient to for extended operation without equipment fouling or repeated meet the specified annual capacity. shutdowns. The parameters inputted for the simulations of the embodi Although particular embodiments of the present invention ments of the processes of the invention are listed in Table 2 have been described in the foregoing description, it will be and follow a process schematic diagram as shown in FIG. 2. understood by those skilled in the art that the invention is 65 In FIG. 2, “QED06” refers to a heat stream representing capable of numerous modifications, Substitutions, and rear process to process heat exchange via heat exchangers 65 and rangements without departing from the spirit of essential 85. Block 60 represents an optional mixer. Block 75 repre US 8,968,522 B2 9 10 sents a mixer combining streams 48 and 44 to provide stream Other key process parameters include the following: 1) the 45. Certain dimensions and duty results calculated from the process model are also listed in Table 2. These parameters do total number of theoretical stages and the bottom stream not include physical property parameters, and those related to water content in the solvent column; 2) the BUOHCOL col convergence and other computational options or diagnostics. umn bottom temperature; and 3) the degree of preheating of TABLE 2 Conditions Used for Modeling Processes of the Invention Equipment blocks Inputs Example 1 Example 2 Units Solvent Column Number of theoretical stages 15 15 Stages (50) including re-boiler Column top pressure bar Column bottom pressure .1 1 bar Column internal diameter 3.71 2 91 l Column re-boiler duty 5961.2 38116 MJAhr Preheated rich solvent feed (10) Stage location Organic reflux from decanter (47) Stage location Mass fraction water in bottom ppm stream (11) Reflux stream temperature 40 40 deg C. Preheated rich solvent stream (10) 17767 7517 kg/hr flow rate Preheated rich solvent stream (10) 91.7 84. 9 deg C. temperature Condenser duty -488.10 -3383 MJAhr BuOHCOL Column Number of theoretical stages 15 15 Stages (80) including re-boiler Column top pressure O.1 O bar Column bottom pressure O.1OS O 105 bar Column internal diameter 2.58 2 46 m Column re-boiler duty 9045 10951 MJAhr Organic feed from solvent column 7 7 Stage (11) location Organic feed from solvent column 145.6 125 deg C. (11) temperature Column bottom temperature 147 147 deg C. Oley alcohol mass fraction in top 100 1OO ppm product (40) Isobutanol mass fraction in 9000 9000 ppm bottom lean solvent (42) Condenser duty -13844 -12278 MJAhr Decanter (70) Decanter pressure 1 1. atn Decanter temperature 40 40 deg C.

Two cases were run to demonstrate the operating require the rich solvent stream before feeding it to the solvent col ments of the processes of the invention. For each case, a umn. These parameters can be manipulated to achieve opti particular modification was made to the rich solventfeed flow 45 mum separation performance. and compositions from the extractive fermentation process where two different aqueous phase titers were maintained. In Example 1 each of the independent simulations, column traffic and heat exchanger duties will change because of the feed composition change. By comparing the resulting capital investment and In this Example, 177,671 kg/hr rich solvent feed (9) con operating costs between different cases, the impact of the rich taining 11.44 weight percent isobutanol is heated from 32.2 to Solvent feed flow and composition on product recovery area 91.7° C. by a process to process heat exchanger and the performance was quantified. These two examples, however, resulting stream (10) is fed to the solvent column (50) at stage should not be regarded as process operating limits of this 1. This rich solvent feed condition corresponds to 20 g/liter invention. aqueous phase titer in the fermentor which is maintained In the Tables, the term “Solvent Column” is synonymous 55 during the extractive fermentation process. The separation is with the term “first distillation columnused above. The term realized by a larger diameter solvent column, higher solvent “BUOHCOL' is synonymous with the term “second distilla column bottom temperature, and higher solvent column re tion column used above. The abbreviation “OLEYLOH boiler and condenser duties. Stream (40) is essentially 100 refers to oleyl alcohol. weight percent isobutanol. Stream (42) contains 0.9 weight Stream results for Example 1 are listed in Table 3. BUO- 60 percent isobutanol and 99.1 weight percent oleyl alcohol. HCOL column traffic and liquid mass composition profiles are listed in Table 4. Solvent column traffic and liquid mass Example 2 composition profiles are listed in Table 5. Stream results for Example 2 are listed in Table 6. BUO In this Example, 75,171 kg/hr rich solvent feed (9) is HCOL column traffic and liquid mass composition profiles 65 heated from 32.2 to 84.9°C. by a process to process heat are listed in Table 7. Solvent column traffic and liquid mass exchanger and the resulting stream (10) is fed to the solvent composition profiles are listed in Table 8. column (50) at stage 1. This rich solvent feed condition cor US 8,968,522 B2 11 12 responds to 40 g/liter aqueous phase titer in the fermenter solvent column re-boiler and condenser duties. Stream (40) is which is maintained during the extractive fermentation pro essentially 100 weight percent isobutanol. Stream (42) con cess. The separation is realized by a smaller diameter solvent tains 0.9 weight percent isobutanol and 99.1 weight percent column, lower solvent column bottom temperature, and lower oleyl alcohol. TABLE 3 Simulated Stream Outputs for Example 1.

9 10 11 30 31 40 42

Temperature C. 32.2 91.7 145.6 92.6 92.6 56.5 147 Pressure atm 1.09 1.04 1.09 O.99 O.99 O.1 O.11 Vapor Frac O 0.157 O 1 1 O O Mole Flow kmohr 1485.305 1485.305 798.584 1075.55 1075.55 243.483 555.101 Mass Flow kg/hr 177671.064 177671.1 163638.7 32370.384 323.70.384 18047.763 145590.98 Volume Flow ?hr 212216.149 6.88E--06 2.19236 3.23E--O7 3.23E--07 234O9.954 193O29.09 Enthalpy MMBtuhr -546.773 -515-113 -315.653 -256.916 -256.916 -75.628 -244.574 Mass Flow kg/hr

I BUOH 2O332.4088 2O332.41 19356.11 15863.657 15863.657 18045.795 1310.31.89 WATER 11496.2539 11496.25 O.163639 14842.689 14842.689 O.1636388 2.67 E-10 CO2 1559.931:42 1559.931 3.18E-23 1656.2O64 1656.2O64 O O OLEYLOH 14428247 144282.5 144282.5 7.83.19222 7.8319.222 1.8047763. 144280.67 Mass Frac

I BUOH O. 11443849 O. 114438 O.118286 O49 OO67 O.49OO67 O.9998.909 O.O09 WATER O.O6470526 O.O64705 1.OOE-06 O4585268 O.4585268 9.07E-06 183E-15 CO2 O.OO877988 O.OO878 194E-28 O.OS11643 O.OS11643 O O OLEYLOH O.812O763S O.812O76 O.881713 OOOO2419 O.OOO2419 O.OOO1 O.991

44 45 46 47 48 49

Temperature C. 45 44.3 40 40 40 40 Pressure atm 1.26 1 1 1 1 O.1 Vapor Frac O O 1 O O O Mole Flow kmohr 555.101 12O3.014 38.774 388.863 647.913 243.483 Mass Flow kg/hr 145591 157963.271 1659.511 18338.586 12372.288 18047.76 Volume Flow ?hr 175750.7 188E--05 9.91E--OS 2.25E-04 12691.227 22984:34 Enthalpy MMBtuhr -276.233 -451.5O2 -13.946 -113.965 -17S.268 -76.401 Mass Flow kg/hr

I BUOH 1310.319 2222.04846 64.7054968. 14887.2216 911.72961.2 18045.79 WATER 2.67E-10 11444.7OSS SO.7448995 3347.23881 11444.7OSS O.163639 CO2 O 15.85241.87 1544.06067 96.2933,369 15.85241.87 O OLEYLOH 144280.7 144280.665 1.02E-O6 7.83188542 3.58E-OS 1.804776 Mass Frac

I BUOH O.OO9 O.O1406686 O.O3899.069 0.81.17977 O.O7369127 O.9998.91 WATER 183E-15 O.O72451.68 O.O3057822 O.182S2437 O.92SO2744 9.07E-06 CO2 O O.OOO10O3S O.93O43108 O.OOS25085 O.OO1281.28 O OLEYLOH O.991 O.91.338109 6.15E-10 O.OOO42707 2.89E-09 O.OOO1

TABLE 4 Simulated BUOHCOL Column Traffic and Liquid Mass Composition Profile Outputs for Example 1. Heat Liquid Vapor Liquid Vapor Mixed Liquid Vapor Temperature Pressure duty flow flow feed feed feed product product Stage C. atn MJAhr kg.hr kg/hr kg/hr kg.hr kg.hr kg/hr kg.hr

1 56.5O116O2. O.1 -13844.4 2793.2042 O O O O 18047.7632 O 2 66.127O606 0.10O357 O 267.O2946 20840.967 O O O O O 3 120.88619 O.10071.4 O 229.713 OS 18314.793 O O O O O 4 122.7SO144 O.101.071 O 229.1764 18277476 O O O O O S 122.786979 0.101.429 O 22844906 18276.94 O O O O O 6 122.794813 O.101786 O 227.724.17 18276.212 O 17089.858 O O O 7 122.802293 0.102143 O 146776.65 1185.629S 146548.89 O O O O 8 122.815489 0.1025 O 146784.87 1185.67O6 O O O O O 9 122.828661 0.102857 O 146793.08 1193.8891 O O O O O 1O 122.84.1823 O.103214 O 1468O1.28 1202.0929 O O O O O 11 122.854977 O.1 03571 O 1468.09.47 1210.2909 O O O O O 12 122.868132 0.103929 O 14681766 1218.485 O O O O O 13 122.882S1 O.104286 O 146825.93 1226.6759 O O O O O US 8,968,522 B2 13 14 TABLE 4-continued Simulated BUOHCOL Column Traffic and Liquid Mass Composition Profile Outputs for Example 1. 14 123.08.2079 0.104643 O 146866.29 1234.94.44 O O O O O 15 147.019984 O.1OS 9045.051 145590.98 1275.3011 O O O 145590.984 O

Stage I BUOH WATER OLEYLOH

1 O.9998.91 9.07E-06 O.OOO1 2 O.245O12 1.93E-07 0.754987 3 O.O17676 1.37E-08 O.98.2324 4 O.O16748 1.32E-08 O.9832S2 5 O.O1679 1.32E-08 O.98321 6 O.O16848 1.33E-08 O.98.3152 7 O.O16906 2.59E-09 O.983 094 8 O.O16961 4.8OE-10 O.983O39 9 O.O1701S 8.85E-11 O.98.2985 10 O.O1707 1.63E-11 O.98.293 11 O.O17124 2.98E-12 O.98.2876 12 O.O17178 5.43E-13 O.98.2822 13 O.O17232 9.86E-14 O.98.2768 14 O.O17188 1.75E-14 O.98.2812 15 O.O09 183E-15 O.991

TABLE 5 Simulated Solvent Column Traffic and Liquid Mass Composition Profile Outputs for Example 1. Temper- Heat Liquid Vapor Liquid ature Pressure duty flow flow feed Stage C. atn MJAhr kg/hr kg/hr kg/hr

1 92.SS78171 O.986923 O 19093O.S 32370.903 1890S8.21 2 93.6721095 0.993973 O 191294.94 27291.757 O 3 93.875775 1001022 O 191366.91 27656.195 O 4 94.06O7027 1008072 O 191435.46 27728.158 O 5 94.242576S 1.0151.21 O 191518.88 27796.707 O 6 94.4133652 1022171 O 191695..12 27880.134 O 7 94.522O752 102922 O 192452.0S 280S6.375 O 8 94.2S67SO9 1.036269 O 19729S41 28813.3 O 9 97.1873.422 1.043319 O 211117.51 33656.66 O 10 106.390013 1.OSO368 O 230900.1 47478.762 O 11 114.30O372 1.057418 O 244353.88 67261.351 O 12 117.024529 1.064467 O 248884.39 80715.128 O 13 117.793.003 1.071517 O 249926.3S 85245.644 O 14 118.6115O1 1.078566 O 243744.67 86.287.599 O 15 145.617646 1.085616 S9612.44 163638.7S 8O105.926 O

1st 2nd Vapor Mixed Liquid Vapor liquid liquid feed feed product product flow flow Stage kg/hr kg/hr kg.hr kg/hr kg.hr kg/hr

1 6951.4374 O O 32369.8779 187271.886 3658.6179 2 O O O O 187484.04 3810.901.9S 3 O O O O 187538.31 3828.59527 4 O O O O 187593.472 3841.98237 5 O O O O 187673.645 3845.23649 6 O O O O 187907.591 3787.53341 7 O O O O 1891.02.216 3349.83052 8 O O O O 197295.407 O 9 O O O O 211117.509 O 10 O O O O 230900.098 O 11 O O O O 244353.875 O 12 O O O O 248884.391 O 13 O O O O 249926.346 O 14 O O O O 243744.673 O 15 O O 163638.747 O 163638.747 O

Stage I BUOH WATER CO2 OLEYLOH

1 O.175304 O.O68834 OOOO144 0.755718 2 O.176064 O.O69654 2.77E-06 0.754279 3 O.176227 0.069777 5.31E-08 0.753996 4 O.176394 O.O69879 1.02E-09 0.753726 5 0.176655 O.O6994.7 197E-11 0.753398 6 O.177494 O.O698O1 3.82E-13 0.752705

US 8,968,522 B2 19 20 What is claimed is: 2. The process of claim 1, further comprising withdrawing 1. A process comprising the steps: the bottoms stream from the second distillation column and a) introducing a feed comprising: introducing at least a portion of the withdrawn bottoms (i) a water-immiscible organic extractant, stream into a fermentation vessel. (ii) water, 3. The process of claim 2, further comprising introducing at (iii) at least one isomer ofbutanol, and least a portion of the aqueous phase to the fermentation ves (iv) optionally a non-condensable gas into a first distil sel. lation column, wherein the first distillation column 4. The process of claim3, wherein at least a portion of the comprises a stripping section and optionally a recti withdrawn bottoms stream and at least a portion of the aque fying section at an introduction point above the strip 10 ping section, the first distillation column having an ous phase are combined before introduction to a fermentation operating temperature, T and an operating pressure vessel. 5. The process of claim 1, wherein a non-condensable gas P at a predetermined point in the stripping section, is present in the feed and the process further comprises purg wherein T and P are selected to produce a first bot ing at least a portion of the gas phase comprising the non toms stream and a first vaporous overhead stream, the 15 first bottoms stream comprising the water-immiscible condensable gas from the process. organic extractant and the at least one isomer of 6. The process of claim 1, wherein the non-condensable gas butanol and being substantially free of water, and the comprises carbon dioxide. first vaporous overhead stream comprising water, the 7. The process of claim 1, wherein the feed further com at least one isomer of butanol, and the optional non prises an organic phase obtained from an extractive fermen condensable gas; tation. b) condensing the first vaporous overhead stream to pro 8. The process of claim 1, wherein the concentration of the duce an optional gas phase and recover a mixed conden at least one isomer of butanol in the feed is from about 0.1 sate, wherein the mixed condensate comprises weight percent to about 40 weight percent, based on the (i) abutanol phase comprising the at least one isomer of 25 weight of the feed. butanol and less than 30 wt % water; and 9. The process of claim 1, wherein the at least one isomer of (ii) an aqueous phase comprising water and less than 10 butanol comprises 1-butanol. wt % of the at least one isomer ofbutanol: c) introducing at least a portion of the butanol phase to the 10. The process of claim 1, wherein the at least one isomer first distillation column; 30 ofbutanol comprises isobutanol. d) introducing a first portion of the first bottoms stream into 11. The process of claim 1, wherein the extractant com a second distillation column having at least a stripping prises at least one solvent selected from the group consisting section and optionally a rectifying section and operating of C, to C fatty alcohols, C7 to C fatty acids, esters of C7 the second distillation column to produce a second bot to C fatty acids, C7 to C fatty aldehydes, and mixtures toms stream comprising the extractant and being Sub 35 thereof. stantially free of the at least one isomer ofbutanol, and a 12. The process of claim 11, wherein the extractant is oleyl second vaporous overhead stream comprising the at alcohol. least one isomer of butanol; and 13. The process of claim 12, wherein the at least one isomer e) introducing at least a portion of the aqueous phase to a ofbutanol consists essentially of 1-butanol. fermentation vessel; 40 wherein the extractant preferentially partitions the at least 14. The process of claim 12, wherein the at least one isomer one isomer of butanol over water and is separable from ofbutanol consists essentially of isobutanol. the at least one isomer of butanol by distillation. k k k k k