Recovery of 3-hydroxypropionic acid with reduced residual sugar and reduced organic acid content

Abstract

Methods of forming a concentrated 3HP solution includes removing organic acid content and reduced residual sugars content. The 3HP recovery process may include a process ion exchange unit operation upstream from a final 3HP distillation unit operation and a polish ion exchange unit operation downstream from the final 3HP distillation unit operation. The concentrated 3HP product with reduced organic acid contamination results from anion exchange in one or both of the process ion exchange unit operation and the polish ion exchange unit operation.

Description

RECOVERY OF 3-HYDROXYPROPIONIC ACID WITH REDUCED RESIDUAL SUGARAND REDUCED ORGANIC ACID CONTENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 632,594, filed April 11. 2024, which is incorporated by reference herein in its entirety applicable.TECHNICAL FIELD

[0002] The present disclosure relates to recovery of 3-hydroxyproponic acid. In particular, the disclosure relates to recovery of 3-hydroxyproponic acid from a fermentation broth.INTRODUCTION

[0003] Hydroxycarboxylic acid monomers are useful in many applications and can be prepared by a number of routes. One method of manufacture includes the use of fermentation, which can produce a number of fermentation products, depending on the fermenting organism selected and other factors. See, for example, U.S. Pat. No. 8,337,663 and U.S. Pat. No. 10,442,749.SUMMARY

[0004] 3-Hydroxypropionic acid (“3HP”) in particular is a desired material that is useful for many industrial applications. It has been discovered that efficient recovery of 3HP in high concentrations and desired purity that is suitable for certain industrial applications is challenging. In particular, process steps intended to efficiently recover 3HP can lead to recovery solutions that either do not contain an appropriate concentration of 3HP for the use in a subsequent process or can lead to introduction of undesired impurities such as undesirable organic acids. This is particularly the case when recovering 3HP on a commercially viable scale.

[0005] Recovery of concentrated 3HP poses additional challenges. Processing streams having higher 3HP concentrations often lead to greater formation of by-products. For example, processing streams having a 3HP concentration greater than 50% or greater than 60% by weight may lead to the formation of acrylic acid, oligomers of 3HP, oligomers of acrylic acid, or combinations thereof. Processing streams having higher 3HP concentrations often include organic acid and residual sugars that are difficult to separate from the 3HP. These organic acid and residual sugars may be problematic when further processing the concentrated 3HP product. The presentinvention provides an advantageous process for recovery of concentrated 3HP with reduced organic acid content and reduced residual sugars content. “Residual sugars” are defined as monosaccharides and polysaccharides (selected from the group consisting of glucose, fructose, sucrose, trehalose, raffinose, maltose, maltotriose, and mixtures thereof), and sugar alcohols (selected from the group consisting of arabitol, erythritol, xylitol, and mixtures thereof).

[0006] Methods of forming a concentrated 3HP solution with reduced organic acid contamination includes utilizing an ion exchange unit operation that selectively removes the unwanted organic acid from the 3HP recovery process. Methods for reducing the residual sugars content in 3HP resulting from the 3HP recovery process are described, below.

[0007] The 3HP recovery process may include a process ion exchange unit operation upstream from a final 3HP distillation unit operation and a polish ion exchange unit operation downstream from the final 3HP distillation unit operation. The concentrated 3HP product with reduced organic acid contamination results from anion exchange in one or both of the process ion exchange unit operation and the polish ion exchange unit operation. Preferably both a process ion exchange unit operation and a polish ion exchange unit operation are utilized.

[0008] The 3HP recovery process may include a process ion exchange unit operation upstream from a final 3HP distillation unit operation. The final concentrated 3HP product with reduced organic acid contamination results from anion exchange in the process ion exchange unit operation.

[0009] Pyruvic acid is an organic acid that is considered an organic acid contaminant. Pyruvic acid (formed during fermentation) may be present in the 3HP stream feeding the process ion exchange unit operation in an amount of about 5 to 20 (or greater than 20) grams per kilogram of 3HP equivalents. The final concentrated 3HP product with reduced organic acid contamination will preferably have less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents (1500 mg), or less than 1 gram of pyruvic acid per kilogram of 3HP equivalents (1000 mg), or less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents (500 mg), or less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents (250 mg), or less than 0.1 gram of pyruvic acid per kilogram of 3HP equivalents (100 mg), or less than 0.05 gram of pyruvic acid per kilogram of 3HP equivalents (50 mg).

[0010] Utilizing an ion exchange unit operation to reduce organic acid contamination, such as pyruvic acid, may advantageously reduce the size or capital cost of the distillation unit, reduce the process water and regeneration chemicals, and improve the efficiency of the concentrated 3HP recover}' system.

[0011] Utilizing ion exchange unit operations both before and after the final 3HP distillation unit operation to reduce organic acid contamination, such as pyruvic acid, may advantageously further reduce the size or capital cost of the distillation unit, and further reduce the process water and regeneration chemicals, and further improve the efficiency of the concentrated 3HP recover}’ system.

[0012] Chevrons and other vapor impingement devices located in the 3HP vapor path (prior to the condenser), and similar devices such as box filters, demister pads and structured packing, can be used to reduce the carry over residual sugars contained in droplets carried with the vapor phase aqueous 3HP, and thereby reduce the concentration of residual sugars carried over to the distillate. Chevrons and other vapor impingement devices located in the 3HP vapor path, such as box filters, demister pads, structured packing, etc. are referred to herein as ‘'vapor impingement device” or “impingement device.” The impingement devices typically cause the entrained droplets earn ing residual sugars to be left in the distillation vessel while the 3HP vapors are condensed by the condenser and move forward for additional processing to the final desired 3HP product stream.

[0013] A method is provided for recovering a concentrated composition of 3- hydroxypropionic acid from a fermentation broth comprising: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration; acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3-hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3-hydroxypropiomc acid; reducing an ion concentration of the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3-hydroxypropionic acid; removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3HP vapor path to form a distilled 3HP stream having reduced residual sugars content and a bottoms stream; and removing pyruvic acid from the distilled 3HP stream with a polish ion exchange unit operation to form a 3HP product stream.

[0014] The method will preferably reduce pyruvic acid in the 3HP product stream to less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents(1500 mg), or less than 1 gram of pyruvic acid per kilogram of 3HP equivalents(1000 mg), or less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents(500 mg), or less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents(250 mg), or less than 0.1 gram of pyruvic acid per kilogram of 3HP equivalents(100 mg), or less than 0.05 gram of pyruvic acid per kilogram of 3HP equivalents(50 mg).

[0015] The method will typically reduce the total residual sugars in the 3HP product stream to less than 1059 mg total residual sugars per kilogram of 3HP equivalents, or less than 824 mg total residual sugars per kilogram of 3HP equivalents, or less than 588 mg total residual sugars per kilogram of 3HP equivalents, or less than 353 mg total residual sugars per kilogram of 3HP equivalents, or less than 176 mg total residual sugars per kilogram of 3HP equivalents.

[0016] Utilizing a weak base anion exchange resin in both the process ion exchange and the polish ion exchange effectively and efficiently removes pyruvic acid and other similar organic acid contaminants in the process stream to recover the 3HP product stream.

[0017] In some aspects, a method is provided for recovering a concentrated composition of 3-hydroxypropionic acid from a fermentation broth comprising: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration; acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3-hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3-hydroxypropionic acid; reducing an ion concentration and pyruvic acid in the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3-hydroxypropionic acid; removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3HP vapor path to form a distilled 3HP stream having reduced residual sugars content and a bottoms stream: wherein the distilled 3HP stream forms a 3HP product stream.

[0018] The method reduces pyruvic acid in the 3HP product stream to less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents, or less than 1 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents; and the method reduces the residual sugars in the 3HP product stream to less than 1059 mg total residual sugars per kilogram of 3HP equivalents, or less than 824 mg total residual sugars per kilogram of 3HP equivalents, or less than 588 mg total residual sugars per kilogram of 3HP equivalents, or less than 353 mg total residual sugars per kilogram of 3HP equivalents, or less than 176 mg total residual sugars per kilogram of 3HP equivalents.

[0019] In further aspects, a method of recovering 3 -hydroxy propionic acid from a fermentation broth, the method comprising the steps of: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration; acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3-hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3-hydroxypropionic acid; reducing an ion concentration in the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3-hydroxypropionic acid, the process ion exchange unit comprising at least a first anion exchange resin bed and a second anion exchange resin bed, the first anion exchange resin bed removing anions until the reduced ion solution reaches 100 ppm total phosphorus and sulfur concentration, then the second anion exchange resin bed begins removing anions and the first anion exchange resin bed is regenerated; removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3 HP vapor path to form a distilled 3HP stream having reduced residual sugars content and a bottoms stream; and removing pyruvic acid from the distilled 3HP stream with a polish ion exchange unit operation to form a 3HP product stream, the polish ion exchange unit comprising at least a first anion exchange resin bed and a second anion exchange resin bed, the first anion exchangeresin bed removing pyruvic acid until the 3HP product stream reaches 0.2 g / kg pyruvic acid concentration, then the second anion exchange resin bed begins removing pyruvic acid and the first anion exchange resin bed is regenerated.

[0020] The process ion exchange unit operation typically includes at least three anion exchange resin beds in a lead-lag configuration. The anion exchange resin beds may include at least a first anion exchange resin bed, a second anion exchange resin bed, and a third anion exchange resin bed. The first anion exchange resin bed and the second anion exchange resin bed removing anions until the reduced ion solution reaches 100 ppm total phosphorus and sulfur concentration (breakthrough) off the first anion exchange resin bed, then the third anion exchange resin bed begins removing anions and the first anion exchange resin bed is regenerated. These anion exchange resin beds are continuously operated in this manner so that at least two anion exchange resin beds are removing anions while the third or remaining anion exchange resin bed is regenerated and on stand-by until the anion exchange resin bed currently in operation experiences breakthrough.

[0021] The polish ion exchange unit operation typically includes at least three anion exchange resin beds in a lead-lag configuration. The anion exchange resin beds may include at least a first anion exchange resin bed, a second anion exchange resin bed, and a third anion exchange resin bed. The first anion exchange resin bed and the second anion exchange resin bed removing pyruvic acid until the reduced ion solution reaches 0.2 g / kg pyruvic acid concentration (breakthrough) off the first anion exchange resin bed, then the third anion exchange resin bed begins removing pyruvic acid and the first anion exchange resin bed is regenerated. These anion exchange resin beds are continuously operated in this manner so that at least two anion exchange resin beds are removing pyruvic acid while the third or remaining anion exchange resin bed is regenerated and on stand-by until the anion exchange resin bed currently in operation experiences breakthrough.

[0022] The method is preferably operated to efficiently and effectively reduce pyruvic acid in the 3HP product stream to less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents, or less than 1 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents.

[0023] “3HP Equivalents’" refers to the total 3-hydroxypropionic species present in the form of 3 -hy droxpropionic acid, homo-oligomers of 3-hydroxypropionic acid, and anionic form of 3-hydroxypropiomc acid present; and 3HP Equivalents concentration refers to the totalconcentration of 3-hydroxypropionic species present in the form of 3-hydroxpropionic acid, homo-oligomers of 3-hydroxypropionic acid, and anionic form of 3-hydroxypropionic acids present (but excluding the metal cations). For example, a homo-oligomer of 3-hydroxypropionic acid would contribute to the total amount of 3-hydroxypropionic acid in an amount equal to the number of repeating units of 3-hydroxypropionic acid in the homo-oligomer. 3HP equivalents is calculated using the following formula when using the molar concentration (mol / kg) of the l~5mer of 3HP determined by the organic acid analysis method: 3HP equivalents (g / kg) = (Molar concentration of monomer 3HP + molar concentration of 3HP dimer x2 + molar concentration of 3HP trimer *3 + molar concentration of 3HP tetramer *4 + molar concentration of 3HP pentamer x5) x 90.

[0024] The term 'upstream’ and 'downstream’ are relative terms that indicate the order of unit operations when viewed from the material flowing through the unit operations from the process system.

[0025] The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate several aspects of the invention and together with a description of the embodiments serve to explain the principles of the disclosure. A brief description of the drawings is as follows:

[0027] FIG. 1 is a process flow diagram of the present disclosure.

[0028] FIG. 2 is another process flow diagram of the present disclosure.

[0029] FIG. 3 is a simplified side view of a distillation system 11 that includes a boiling tube 17 evaporator operating as a boiling film evaporator 15 and that also utilizes vapor impingement device(s) located in a vapor impingement section 26 between the boiling tube evaporator 15 and the condenser 27.

[0030] FIG. 4 is a side view of one of several boiling tubes 17 located within the boiling film evaporator 15.

[0031] FIG. 5 is a diagram of the apparatus used for dehydration of 3HP to acrylic acid as described in Example 8.DETAILED DESCRIPTION

[0032] The aspects of the present disclosure described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, a purpose of the aspects chosen and described is so that the appreciation and understanding by others skilled in the art of the principles and practices of the present invention can be facilitated.

[0033] All pressure measurements are reported as absolute pressures.

[0034] 3-Hydroxypropionic acid C‘3HP’?) in particular is a desired material that is useful for many industrial applications. It has been discovered that efficient recovery of 3HP in high concentrations and high purity is challenging. In particular, process steps intended to efficiently recover 3HP can lead to recover}' solutions that either do not contain an appropriate concentration of 3HP for use in a subsequent process or can lead to introduction of undesired impurities or byproducts. For example, it is challenging to recover 3HP at high concentrations without dehydrating the 3HP to form acrylic acid, acrylic acid oligomers, homo-oligomers of 3HP, and the like, in undesirable amounts. It is also challenging to remove organic acid contaminants such as pyruvic acid.

[0035] Organic acid contamination may reduce the yield of 3HP reaction products for downstream processors using the 3HP product stream as a feedstock. Organic acids (other than 3HP), such as pyruvic acid, not removed from the 3HP product stream are problematic to the conversion of 3HP to acry lic acid (AA) via acid catalyzed dehydration. Acidic conditions promote esterification reactions between organic acids and 3HP. Some organic acids, such as pyruvic acid, are known to undergo polymerization reactions in acidic conditions. Both of these processes tend to reduce the yield of the acid catalyzed dehydration of 3HP to acry lic acid and are undesirable.

[0036] 3HP solutions are sensitive to heat, as heat and time will promote the formation of acrylic acid, acrylic acid oligomers, and homo-oligomers of 3HP. Reducing the heat history (a function of amount of heat and elapsed time) of 3HP solutions is helpful in minimizing the formation of acry lic acid, acrylic acid oligomers, and homo-oligomers of 3HP. Reducing the heat history (a function of amount of heat and elapsed time) of 3HP solutions is helpful in improving overall recovery of 3HP Equivalents utilizing the process described herein. Storing 3HP solutions, pre-distillation, containing greater than 20 wt% 3HP Equivalents at room temperature (24 degrees Celsius) is preferably limited to less than 12 days, or less than 1 week. Storing 3HP solutions containing greater than 50 wt% 3HP Equivalents at room temperature (24 degrees Celsius) ispreferably limited to less than 8 days, or less than 5 days or less than 3 days or preferably less than 2 days or less than 24 hours. As the temperature of the 3HP solutions increases, the amount of time for storage and processing needs to decrease to prevent the formation of undesirable amounts of acry lic acid, acrylic acid oligomers, or homo-oligomers of 3HP. Storing 3HP solutions, postdistillation. may or may not follow the above description based on whether the further processing tolerates increased amounts of acrylic acid, acrylic acid oligomers, or homo-oligomers of 3HP.

[0037] It is challenging to remove organic acid contaminants such as pyruvic acid and lactic acid from the 3HP process streams. Evaporation or distillation fails to efficiently separate pyruvic acid and / or other similar organic acids from the 3HP while separating some sugar and other heavy’ boilers from 3HP. Pyruvic acid and other similar organic acids carry’ over with 3HP as overhead product in evaporation or distillation unit operations, making separation of pyruvic acid and other similar organic acids from the 3HP difficult since they tend to concentrate as 3HP concentrates with liquid-vapor separation unit operations. Additionally, residual sugars may be contained in droplets entrained with the 3HP vapors and may be carried over into the distillate that contains the aqueous 3HP. It has been found that vapor impingement devices, such as chevrons, box filters, demister pads, structured packing, and the like can be positioned in the 3HP vapor path. The entrained residual sugar droplets will impinge upon these impingement devices and thereby pass back to the pot, while the 3HP vapors will be passed ty pically to a condenser, whereby the 3HP vapor is liquified. The use of such vapor impingement devices in the 3HP vapor path will significantly reduce the concentrations of residual sugars in the 3HP product stream.

[0038] The present disclosure provides an advantageous process for recovery of concentrated 3HP with low levels of organic acid contaminants by utilizing one or more ion exchange unit operations. In particular, one or more anion exchange unit operations may be configured to selectively remove organic acid contaminants (such as pyruvic acid, lactic acid, succinic acid, malic acid, and the like) from the 3HP process streams, before and / or after a distillation unit operation. Due to the characteristics of pyruvic acid, the anion exchange unit operations are typically run to optimize the removal of pyruvic acid.

[0039] Preferably, methods utilizing anion exchange both before and after a distillation unit operation are provided for recovering a concentrated composition of 3-hydroxypropionic acid having reduced pyruvic acid and reduced residual sugars from a fermentation broth comprising: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration;acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3-hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3-hydroxypropionic acid; reducing an ion concentration of the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3-hydroxypropionic acid; removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3 HP vapor path to form a distilled 3HP stream having reduced residual sugars content and a bottoms stream; and removing pyruvic acid from the distilled 3HP stream with a polish ion exchange unit operation to form a 3HP product stream.

[0040] The 3HP product stream preferably has less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents (1500 mg). The 3HP product stream preferably has less than 1 gram of pyruvic acid per kilogram of 3HP equivalents (1000 mg). The 3HP product stream preferably has less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents (500 mg). The 3HP product stream preferably has less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents (250 mg). The 3HP product stream preferably has less than 0. 1 gram of pyruvic acid per kilogram of 3HP equivalents (100 mg).

[0041] The 3HP product stream typically has less than 1059 mg total residual sugars per kilogram of 3HP equivalents, or less than 824 mg total residual sugars per kilogram of 3HP equivalents, or less than 588 mg total residual sugars per kilogram of 3HP equivalents, or less than 353 mg total residual sugars per kilogram of 3HP equivalents, or less than 176 mg total residual sugars per kilogram of 3HP equivalents.

[0042] The 3HP product stream may have at least 55% by weight 3HP equivalents. The 3HP product stream may have at least 60% by weight 3HP equivalents. The 3HP product stream may have at least 65% by weight 3HP equivalents. The 3HP product stream may have at least 70% by weight 3HP equivalents.

[0043] The method may further include concentrating the 3HP product stream to at least 80% by weight 3HP equivalents, or at least 85% by weight 3HP equivalents, or at least 90% byweight 3HP equivalents forming a concentrated 3HP product. Concentrating may include evaporating the 3HP product stream to form the concentrated 3HP product.

[0044] The acidified solution (feeding the process ion exchange unit operation) may have greater than 5 grams of pyruvic acid per kilogram of 3HP equivalents. The acidified solution (feeding the process ion exchange unit operation) may have greater than 10 grams of pyruvic acid per kilogram of 3HP equivalents.

[0045] Ion exchange units for both cation exchange and anion exchange are composed of multiple resin beds arranged in a lead-lag or continuous configuration. This lead-lag configuration includes at least two resin beds and preferably at least three resin beds. In these lead-lag systems typically the ion exchange feed (cation or anion) is directed into a first resin bed and the permeate of the first bed is directed into the next bed in series. The permeate is removed from the ion exchange system following the second resin bed in a lead-lag system and the product draw-off location of a continuous system. The permeate of the first resin bed is monitored for breakthrough to determine when the column is switched from production mode to rinse and regeneration mode. As the first resin bed is switched to rinse and regeneration mode, the ion exchange feed (cation or anion) is directed to the second resin bed and the permeate from the second resin bed is directed to the third resin bed. This cycling of resin beds is continued during processing of ion exchange feed.

[0046] Preferably, the process ion exchange unit operation includes a bed of cation exchange resin followed by a bed of anion exchange resin in series. The cation exchange resin is preferably a strong acid cation resin, such as resin available under the trade designation Amberlite FPC88 from DuPont, for example. The anion exchange resin is preferably a weak base anion resin, such as resin available under the trade designation Amberlite FPA53 from DuPont, for example. Running a process ion exchange unit with the preferred resin types and with the cation exchange resin bed upstream of the anion exchange resin bed improves the efficiency of the anion exchange resin containing bed to remove anions under the operating conditions utilized (e.g., acidic conditions).

[0047] Weakly binding anions exhibit differential binding to weak base anion resin. Weak base anion resin preferentially separates detrimental organic acids from 3HP. This binding property reduces the concentration of detrimental organic acids from 3HP which has an unexpectedly and surprising lower affinity' to weak base anion resin compared to other organic acids found in broth produced in a fermentation process.

[0048] Strongly binding anions, such as chloride, phosphorus, and sulfur preferentially bind to the weak base anion resin. As used herein the term 'phosphorus’ refers to any form of anionic phosphorus species such as phosphate. As used herein the term 'sulfur’ refers to any form of anionic sulfur species such as sulfate.

[0049] Thus, organic acids ‘breakthrough’ before chloride, phosphorus (phosphate), and sulfur (sulfate) ‘breakthrough’ the bed of weak base anion resin. Therefore, the bed of anion exchange resin can be operated to first reduce strongly binding anions, and then a bed of anion exchange resin can be operated to reduce weakly binding anions.

[0050] This two-step anion removal process may be accomplished with a dual anion exchange resin beds both prior to distillation (process ion exchange unit operation, or one anion exchange resin bed upstream of distillation (process ion exchange unit operation) and one anion exchange resin bed downstream of distillation (polish ion exchange unit operation).

[0051] The polish ion exchange unit operation includes a bed of anion exchange resin. The polish ion exchange unit operation preferably includes a bed of cation exchange resin upstream from the bed of anion exchange resin. The cation exchange resin is preferably a strong acid cation resin, such as resin available under the trade designation Amberlite FPC88 from DuPont, for example. The anion exchange resin is preferably a weak base anion resin, such as resin available under the trade designation Amberlite FPA53 from DuPont, for example.

[0052] Utilizing an anion exchange resin bed upstream of distillation (process ion exchange unit operation) to remove strongly binding anions such as chloride, phosphorous (phosphate), and sulfur (sulfate) and an anion exchange resin bed downstream of distillation (polish ion exchange unit operation) to remove weakly binding anions such as pyruvic acid and similar organic acids, results in less chemical and water consumption than a single unit operation that reduces all anions.

[0053] The process ion exchange unit operation typically removes at least 90% of total phosphate and sulfate ions from the acidified solution (when the process ion exchange unit operation is operated to breakthrough of the strongly binding anions). The process ion exchange unit operation typically removes from 10% to 70%, or from 10% to 65% from 10% to 60% pyruvic acid from the acidified solution (when the process ion exchange unit operation is operated to breakthrough of the strongly binding anions).

[0054] The polish ion exchange unit operation removes at least 90% of pyruvic acid from the distilled 3HP stream (when the polish ion exchange unit operation is operated to breakthrough of the weakly binding anions of pyruvic acid). The polish ion exchange unit operation removes atleast 95% of pyruvic acid from the distilled 3HP stream (when the polish ion exchange unit operation is operated to breakthrough of the weakly binding anions of pyruvic acid).

[0055] Further methods are provided utilizing anion exchange before a distillation unit operation for recovering a concentrated composition of 3-hydroxypropionic acid from a fermentation broth comprising: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration; acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3-hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3-hydroxypropionic acid; reducing an ion concentration and pyruvic acid in the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3-hydroxypropionic acid; removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3 HP vapor path to form a distilled 3HP stream having reduced residual sugars content and a bottoms stream; wherein the distilled 3HP stream forms a 3HP product stream.

[0056] The 3HP product stream preferably has less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents. The 3HP product stream preferably has less than 1 gram of pyruvic acid per kilogram of 3HP equivalents. The 3HP product stream preferably has less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents. The 3HP product stream preferably has less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents. The 3HP product stream preferably has less than 0. 1 gram of pyruvic acid per kilogram of 3HP equivalents.

[0057] The 3HP product stream typically has less than 1059 mg total residual sugars per kilogram of 3HP equivalents, or less than 824 mg total residual sugars per kilogram of 3HP equivalents, or less than 588 mg total residual sugars per kilogram of 3HP equivalents, or less than 353 mg total residual sugars per kilogram of 3HP equivalents, or less than 176 mg total residual sugars per kilogram of 3HP equivalents.

[0058] The 3HP product stream may have at least 55% by weight 3HP equivalents. The 3HP product stream may have at least 60% by weight 3HP equivalents. The 3HP product stream may have at least 65% by weight 3HP equivalents. The 3HP product stream may have at least 70% by weight 3HP equivalents.

[0059] The method may further include concentrating the 3HP product stream to at least 80% by weight 3HP equivalents, or at least 85% by weight 3HP equivalents, or at least 90% by weight 3HP equivalents forming a concentrated 3HP product. Concentrating may include evaporating the 3HP product stream to form the concentrated 3HP product.

[0060] The acidified solution (feeding the process ion exchange unit operation) may have greater than 5 grams of pyruvic acid per kilogram of 3HP equivalents. The acidified solution (feeding the process ion exchange unit operation) may have greater than 10 grams of pyruvic acid per kilogram of 3HP equivalents.

[0061] The process ion exchange unit operation includes a bed of cation exchange resin and a bed of anion exchange resin in series. The cation exchange resin preferably is a strong acid cation resin, such as resin available under the trade designation Amberlite FPC88 from DuPont, for example. The anion exchange resin preferably is a weak base anion resin, such as resin available under the trade designation Amberlite FPA53 from DuPont, for example.

[0062] Strongly binding anions, such as chloride, phosphorous (phosphate), and sulfur (sulfate) preferentially bind to the weak base anion resin. Thus, organic acids 'breakthrough' before chloride, phosphorus, and sulfur ‘breakthrough’ the bed of weak base anion resin.

[0063] Here the process ion exchange unit operation anion exchange resin bed may be operated to organic acid breakthrough. Therefore, the anion exchange resin bed must be regenerated more often than the same anion exchange resin bed operated to breakthrough of chloride, phosphorous, or sulfur, since organic acids such as pyruvic acid breakthrough before chloride, phosphorus, and sulfur breakthrough.

[0064] The process ion exchange unit operation preferably removes at least 90% of total phosphate and sulfate ions from the acidified solution (when the process ion exchange unit operation is operated to breakthrough of the weakly binding anions). The process ion exchange unit operation may remove at least 90% of pyruvic acid from the acidified solution (when the process ion exchange unit operation is operated to breakthrough of the weakly binding anions of pyruvic acid). The process ion exchange unit operation may remove at least 95% of pyruvic acid from the acidified solution (when the process ion exchange unit operation is operated to breakthrough of the weakly binding anions of pyruvic acid). The process ion exchange unitoperation may remove at least 50% of lactic acid from the acidified solution (when the process ion exchange unit operation is operated to breakthrough of the weakly binding anions of lactic acid).

[0065] 3HP and / or salts thereof is generated by a fermentation process using known fermentation techniques. For purposes of the present discussion, 3HP and / or salts means that the compound 3-hydroxypropionic acid is present either in its acid form or in a salt form or in a mixture of the acid form and the salt form. The salt form may include one or more counter ions, for example calcium 3-hydroxypropionate, which is present at a higher pH.

[0066] During the fermentation process, various ingredients are added to the fermentation broth to establish and maintain favorable nutrition and pH conditions to support the particular organism carrying out the fermentation. Preferably, an enzyme (or enzymes) is added that cleaves polysaccharides that are not fermentable by the organism being utilized. The enzymes convert at least some of the polysaccharides to monosaccharides, such as a glucose that can be used by the organism to make 3HP. This will increase the yield of 3HP based on the fermentation carbon source being used and will also reduce the amounts of residual sugars that are contained in the fermentation broth and later during processing concentrated 3HP. This will further reduce the amounts of residual sugars contained in the fermentation broth that is to be processed and thereby assist in reducing these residual sugars concentration in the final 3HP product stream. Examples of the enzymes that can be added to the fermentation broth during the fermentation include, but are not limited to, saccharification enzy mes such as glucoamylase, transglucosidase, alphaamylase, and mixtures thereof. After completion of the fermentation, various ionic species are present in the fermentation broth that are desirable to remove.

[0067] FIG. 1 is a process flow diagram illustrating the present disclosure. The process includes: a fermentation step (1) to form the 3-hydroxypropionic acid and / or salts thereof; a cell separation step (2) to remove fermentation organisms or cells from the fermentation broth; a first evaporation step (3) to remove a first amount of water from the fermentation broth; an acidulation step (4) to lower the pH of the fermentation broth and precipitate a calcium salt from the fermentation broth; a separation step (5) to separate suspended solids from the acidified broth; a process ion exchange step (6) to remove ions (cations and anions) from the aqueous solution; and a second evaporation step (7) to remove a second amount of water from the aqueous solution, forming a distillation feed stream. The process then includes distilling the distillation feed stream at step (8), a polish ion-exchange step (9), and an optional post distillation evaporation step, as further described below and in the Examples.

[0068] The process includes: providing a fermentation broth having a pH of from about 2 to about 6 (or from 3 to 5) and comprising 3HP or salts thereof, and a calcium ion concentration; acidifying the fermentation broth (preferably with sulfuric acid) to lower the pH from about 1 to about 3 to form an aqueous solution comprising 3HP and produce an isolatable material comprising calcium, preferably a calcium sulfate compound; separation of the isolatable material comprising calcium from the rest of the solution; reducing an ion concentration to produce a reduced ion aqueous solution comprising 3HP; and removing water from the reduced ion aqueous solution to form a distillation feed stream having a feed stream 3HP concentration in a range from 30% to 70% by weight, or from 40% to 60% by weight.

[0069] The distillation feed stream includes 3HP in an amount from 30% to 70% by weight. The distillation feed stream includes 3HP in an amount from 40% to 60% by weight. The distillation feed stream includes 3HP in an amount from 50% to 60% by weight. The distillation feed stream includes 3HP in an amount from 45% to 55% by weight. Providing the distillation feed stream with a concentration of 3HP above 60% increases the formation of impurities and reduces the recovery of 3HP via distillation. Providing the distillation feed stream with a concentration of 3HP below 40% increases the capital costs for the distillation at a given throughput or capacity.

[0070] The temperature of the distillation feed stream (prior to distillation) is controlled to be less than 80 degrees Celsius, or less than 75 degrees Celsius, or less than 70 degrees Celsius. The residence time of the distillation feed stream prior to distillation (for example in a storage take or piping) is less than 75 minutes, or less than 45 minutes, or less than 30 minutes, preferably less than 20 minutes, or less than 10 minutes, at 80 degrees Celsius. The residence time of the distillation feed stream prior to distillation is less than 150 minutes, or less than 90 minutes, or less than 65 minutes, preferably less than 45 minutes, or less than 20 minutes, at 70 degrees Celsius. The residence time of the distillation feed stream prior to distillation is less than 300 minutes, or less than 190 minutes, or less than 140 minutes, preferably less than 90 minutes, or less than 46 minutes, at 60 degrees Celsius. Minimizing both the residence time and temperature of the distillation feed stream (heat history) prior to distillation improves the recovery of 3HP via distillation. Minimizing both the residence time and temperature of the distillation feed stream reduces the formation of 3HP impurities in the distillation feed stream, as described above.

[0071] One impurity that may be formed in the distillation feed stream is acrylic acid. Reducing the heat load or heat history on the distillation feed stream may inhibit or reduce the amount of acrylic acid in the distillation feed stream. The distillation feed stream may have lessthan five parts by weight acrylic acid per one hundred parts by weight 3HP equivalents, or less than three parts by weight acrylic acid per one hundred parts by weight 3HP equivalents, or less than one part by weight acrylic acid per one hundred parts by weight 3HP equivalents.

[0072] Another impurity' that may be formed in the distillation feed stream is a homooligomer of 3-hydroxypropionic acid. Reducing the heat load on the distillation feed stream may inhibit or reduce the amount of homo-oligomer of 3HP in the distillation feed stream. The distillation feed stream may have less than five parts by weight homo-oligomer of 3HP per one hundred parts by weight 3HP equivalents, or less than three parts by weight homo-oligomer of 3HP per one hundred parts by weight 3HP equivalents, or less than one part by weight homooligomer of 3HP per one hundred parts by weight 3HP equivalents. Homo-oligomers of 3HP in the distillation feed stream end up in the bottoms product of distillation forming a bottoms product of distillation that results in a lower recovery of 3HP Equivalents.

[0073] Referring to FIG. 1 step (1) of the present process, a fermentation broth is provided having a pH of from 2 to 6. ty pically 3 to 5, comprising 3HP and / or salts thereof, and calcium ions (and optionally sulfate ions, and phosphate ions) concentration of typically at least 1000 ppm, for example at least about 3000 ppm, at least about 5000 ppm, at least 6000 ppm, and in some instances at least about 7000 ppm. The fermentation broth has a pH of from about 3 to about 5 in step (1), or the fermentation broth has a pH of from about 2.5 to about 4.5 in step (1), or the fermentation broth has a pH of from about 4 to about 5 in step (1). Lower pH levels of the fermentation broth are advantageous for certain fermentation organisms that can ferment at commercially acceptable rates at low pH.

[0074] The concentration of 3HP and / or salts thereof in the fermentation broth of step (1) is from 50 to 200 grams of 3HP Equivalents per liter of broth. The concentration of 3HP and / or salts thereof in the fermentation broth of step (1) is from 70 to 150 grams of 3HP Equivalents per liter of broth. The concentration of 3HP and / or salts thereof in the fermentation broth of step (1) is from about 80 to about 130 grams of 3HP Equivalents per liter of broth.

[0075] Referring to FIG. 1, cells from the fermentation process are removed from the fermentation broth at step (2) prior to addition of acid, so the amount of biological materials present in the isolatable material or like material that is removed is below the amount unsuitable for end use of this product. Alternatively, the cells may be removed after the acidification step (4), together with the removal of insoluble and / or easily isolatable material that may be formed during the acidification step. Cell separation may be accomplished by microfiltration or centrifugation of the fermentation broth.

[0076] Referring to FIG. 1 step (3) of the present process, the concentration of 3HP and / or salts thereof in the fermentation broth of step (a) is increased to from 100 to 500 grams of 3HP Equivalents per liter of broth by evaporating a portion of the liquid present in the fermentation broth at a broth temperature of from 60° C to 100° C. In an embodiment, the concentration of 3HP and / or salts thereof in the fermentation broth is increased to from 250 to 400 grams, and in some aspects from 140 to 400 grams, from 150 to 350 grams, from 200 to 330 grams, from 220 to 320 grams, or from 230 to 300 grams of 3HP Equivalents per liter of broth.

[0077] The increase of concentration of 3HP in this step is particularly advantageous in providing an economic process. In an embodiment, the evaporation of liquid typically takes place at a broth temperature of from about 65° C to about 90° C. In an embodiment, typically the evaporation of liquid takes place at a pressure of from 200 to 300 Torr, or from 200 to 250 Torr.

[0078] Referring to FIG. 1 step (4) of the present process, the fermentation broth is acidified to lower the pH to from about 1 to about 3 to form an aqueous solution including 3HP. It has been found that reducing the pH of the aqueous solution comprising 3HP provides processing benefits when 3HP is in the acid form and is beneficial for the recovery of 3HP. In an embodiment, typically the pH of the aqueous solution is lowered to a pH of from about 1.5 to about 2.5 in step (4), and in some aspects from a pH of 2.0 to a pH of 2.5. Typically, the aqueous solution 3HP Equivalents is made up of at least 95% by weight 3HP, at least 98% by weight 3HP, at least 99% by weight 3HP.

[0079] As discussed above, during the fermentation process, various ingredients are added to the fermentation broth to establish and maintain favorable nutrition and pH conditions to support the particular organism carrying out the fermentation. And, as discussed above, a saccharification enzyme or enzymes may be added during the fermentation to reduce the amounts of residual sugars remaining at the end of the fermentation. After completion of the fermentation, various ionic species are present that are desirable to remove. The removal of certain ions is facilitated in the acidification step through the formation of insoluble and / or easily isolatable material. For example, undesired calcium present in the fermentation broth is removed bylowering the pH through the addition of H2SO4 (sulfuric acid) or other acidic compounds that will form insoluble and / or easily isolatable material with calcium. Addition of H2SO4 is preferred because the resulting isolatable material contains a calcium sulfate compound (for example, calcium sulfate dihydrate). The various forms of calcium sulfate are hereinafter referred to as “gypsum.” In addition, other insoluble salts and suspended solids may be removed with the gypsum.

[0080] Referring to FIG.l step (5) of the present process, the insoluble and / or easily isolatable material are removed by conventional equipment, such as use of a centrifuge, a belt filter, a drum filter, or membrane filter, or other appropriate separation techniques.

[0081] Referring to FIG. 1 step (6) of the present process, ion concentration of the aqueous solution is reduced with a process ion exchange unit operation. Both cations and anions are removed from the acidified solution. The acidified solution typically includes a sulfate ion. that may be present in the fermentation broth and may also be added as sulfuric acid during the acidulation step (4). The acidified solution typically includes a phosphate ion, that may be present in the fermentation broth.

[0082] This ion exchange step (6) captures ions (cations and anions) from the acidified solution to form a reduced ion solution. The ion concentration (such as one or more of calcium, sulfate and phosphate, for example) of the reduced ion solution produced in step (6) is typically less than 1,000 ppm, preferably less than 550 ppm (for example from 200 ppm to 550 ppm and preferably from 200 ppm to 500 ppm). Reduction of the ion content in the acidified solution prior to distillation is advantageous, because it has been found that carrying out these steps in this order reduces the amount of undesired side products and impurities present in the final recovered distillation product. In particular, reduction of the ion content of the acidified solution prior to distillation beneficially reduces the amount of acrylic acid formed in subsequent steps of the 3HP recovery process, and also reduces the boiling point of the reduced ion solution, and reduces the energy needed to recover the 3HP.

[0083] Referring to FIG. 1 step (6) of the present process, reducing the ion concentration of the aqueous solution is carried out by utilizing a process ion exchange unit operation. Preferably the process ion exchange unit operation includes a cation exchange resin and an anion exchange resin. Preferably, the cation exchange resin bed and anion exchange resin bed are fluidly connected in series with the cation exchange resin bed located upstream of the anion exchange resin bed. The amount of positively charged ions in the aqueous solution is reduced by use of an ion exchanger that includes a cation exchange resin. The amount of negatively charged ions in the aqueous solution is reduced by use of an ion exchanger that includes an anion exchange resin. Typically, the pH of the reduced ion aqueous solution once passed through cationic and anionic exchange resins is about 0.1 to 1 pH units lower than the pH of the aqueous solution prior to being treated by the ion exchange resins. For example, the pH of the reduced ion aqueous solution typically is from 1.2 to 2.4.

[0084] Referring to FIG 2, the process ion exchange unit operation may be operated to 'breakthrough’ of either strongly binding anions or weakly binding anions as described herein. If the process ion exchange unit operation is operated to breakthrough of weakly binding anions, then pyruvic acid and other similar organic acids will be reduced in the process stream leaving the process ion exchange unit operation, as described herein. Additionally, other weak organic acids in the salt or free acid form and strongly binding anions (such as chloride, sulfates, and phosphates) will also be reduced when the ion exchange unit is operated based on breakthrough of pyruvic acid.

[0085] Referring to FIG. 1 step (7), the evaporator may be any evaporator that concentrates the 3HP containing solution from the step (6) (preferably minimizing the heat load). During step (7), the evaporator typically operates at a temperature of 80 degrees Celsius or less, or in a range from 60 to 80 degrees Celsius. In an aspect the evaporator of step (7) is a mechanical vapor recompression (MVR) evaporator (as described below). In another aspect, the evaporator is a flash-type evaporator (as described below). Preferably, the evaporator of step (7) is a MVR evaporator.

[0086] Referring to FIG. 1 step (8), the reduced ion aqueous solution is distilled by applying vacuum and heat to the reduced ion aqueous solution to form an aqueous distillation product including 3HP. The use of ‘'more gentle” distillation techniques involving application of vacuum and lower levels of heat than would otherwise be required in a distillation process undertaken at standard pressure is advantageous because it reduces the likelihood of formation of undesired side products in the recovery process.

[0087] The heating fluid temperature of the first distillation unit operation is typically from 140 °C to 190 °C, preferably from 140 °C to 180 °C, and more preferably from 155 °C to 178 °C. The pressure of the first distillation unit operation is typically from 10 to 50 mbar. preferably from 20 to 50 mbar, or from 20 to 40 mbar.

[0088] The distillation step (8) results in a bottoms stream and a 3HP product stream having a 3HP Equivalents concentration of about 30% to 70% (for example from 40% to 60%) byweight 3HP.

[0089] Referring to FIG. 1 step (9) the distilled 3HP stream is then passed through a polish ion exchange unit operation. The polish ion exchange unit operation includes an anion exchange resin and optionally a cation exchange resin. The polish ion exchange unit operation is operated to breakthrough of weakly binding anions, such as pyruvic acid. Pyruvic acid and other similar organic acids are reduced in the 3HP product stream leaving the polish ion exchange unitoperation, as described herein. If the polish ion exchange unit includes a bed containing cation exchange resin, the polish ion exchange unit preferably is operated to reduce calcium, iron and other metal ions (such as metal ions released from the metals used in the process equipment). Typically, the ion exchange unit includes a cation exchange resin bed and it is ty pically operated to reduce metal ions in the 3HP product stream to 20 mg or less, preferably 10 mg or less, and more preferably less than 5 mg or less based on a kilogram of 3HP Equivalents present in the 3HP product stream.

[0090] The 3HP product stream may be further concentrated via an evaporation unit operation. The evaporation unit operation removes water and concentrates the 3HP product stream to form a concentrated 3HP product.

[0091] Reducing the heat load on the distillation process stream and optional post distillation evaporation process stream reduces the amount of acrylic acid or oligomers of acrylic acid in the 3HP product stream. The 3HP product stream may have less than five parts by weight acrylic acid per one hundred parts by weight of 3HP equivalents, or less than three parts by weight acrylic acid per one hundred parts by weight of 3HP equivalents, or less than one part by weight acrylic acid per one hundred parts by weight of 3HP equivalents. Reducing the heat load on the optional post distillation evaporation process stream inhibits or reduces the amount of homooligomer of 3HP in the concentrated 3HP product stream. However, due to the heat history during distillation and optional evaporation, the concentrated 3HP product stream typically will have at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, and in some instances at least 40 wt% 3HP oligomers of the total 3HP Equivalents, depending on the heat history and length of time the concentrated 3HP product stream is maintained at the very high concentration.

[0092] Referring to FIG. 1 and FIG. 2, the distillation step (8) and optional evaporation step is preferably carried out by short residence time distillation techniques or distillation unit operations. The distillation step (8) is preferably carried out by equipment selected from wiped film evaporation equipment, rising film evaporator equipment, thin film evaporation equipment, (centrifugal) molecular distillation equipment, falling film distillation equipment, rising film evaporation (such as a boiling tube evaporator), or combinations, thereof. An evaporation step may be carried out after step 9 in FIG. 1 and / or after step 8 in FIG 2. The evaporation step is preferably carried out by a mechanical vapor recompression (MVR) evaporator. In an embodiment, the evaporator is a flash-type evaporator.

[0093] Referring to FIG. 3 a distillation system 11 is depicted. System 11 comprises a Boiling Tube Evaporator (BTE) feed pump 13 that pumps the 3HP containing liquid to be distilledinto the BTE section 15 of the rising film evaporator distillation system 11. Within BTE section 15 are boiling tubes 17 dispersed to form a tube sheet. BTE section 15 is a tube in shell heat exchanger. With the 3HP containing liquid located within tubes 17 and the heating fluid (water, oil, or steam) surrounding tubes. For ready availability' and cost, steam is the preferred heating fluid. The 3HP containing liquid enters BTE section 15 at the bottom and partially vaporizes leaving heavier molecules in the liquid phase while the 3HP and water rises to the top of the tube sheet as vapor.

[0094] Referring to FIG. 4, a side view of one of the boiling tubes 17 shows that the 3HP containing liquid starts at the bottom of the boiling tube 17 as a single-phase liquid. As the 3HP containing liquid moves up the boiling tube 17 heating causes nucleate boiling of the liquid and bubbly flow. As you move up boiling tube 17, it can be seen that more and more of the 3HP and water are converted to vapor 19, and the higher boiling materials 21 coalesce along the wall 23 of the boiling tube 17. It can be seen that toward the top of boiling tube 17 a majority' of the 3HP and water are vapor with small liquid droplets of higher boiling liquids 24 (such as droplets containing monosaccharides, polysaccharides and sugar alcohols).

[0095] The liquid traveling along the walls 23 of the boiling tubes 17 that are not vaporized are collected as overflow bottoms at outlet 25 (FIG. 3). The overflow bottoms typically are combined with the entrained bottoms to form a single bottom stream, which may be further treated to recover 3HP contained therein.

[0096] Referring to FIG. 3, distillation system 11 further comprises a vapor impingement device located within the 3HP vapor path. The entrained liquid and vapor mixture along the center of the tubes exits boiling tubes 17 and passes through the vapor impingement section 26, where entrained liquids (entrained bottoms) are removed from the 3HP and water vapor. The vapor impingement devices typically comprise chevron separators, demister pads and structured packing and other vapor impingement devices located in the vapor impingement section 26.

[0097] Referring to FIG. 3, distillation system 11 further comprises a condenser 27. The 3HP and water vapors that pass through the vapor impingement section 26, are condensed to liquid in condenser 27. Typically, the vapor passes through the shell side of condenser 27. while cooling water passes through condenser tubes 29. A vacuum is typically maintained on the shell side of condenser 27 by applying a vacuum through vacuum adapter 31 assist in the recovery of 3HP, which is collected as distillate through distillate outlet 33. It has been found that using vapor impingement devices can greatly reduce the residual sugar content in the distillate.EXAMPLES

[0098] Representative embodiments of the present disclosure will now be described with reference to the following example that illustrates the principles and practice of the present invention. The following analytical methods and sample preparations are used in the examples below.Analytical Method for 3HP

[0099] 3-Hydroxypropionic acid (3HP), acrylic acid, and various other organic acids, alcohols, and sugars in the samples may be analyzed using high performance liquid chromatography (HPLC). This HPLC method utilizes a combination of two BioRad Aminex HPX-87H columns, in conjunction with Refractive Index (RI) detection and Ultraviolet (UV) detection at 210 nm. The RI detector is for the quantification of alcohols and sugars, and the UV detector for all the organic acids. Standards and samples are prepared by mass in volumetric flasks diluted with the mobile phase. No internal standard is used. Results are calculated in weight %.

[0100] The HPLC is a Waters Alliance 2695 modular High Performance Liquid Chromatography system that includes a pump, auto-sampler, solvent in-line degasser, and column heater. The RI detector is a Waters 2410 Refractive Index Detector, and the UV detector a Waters 2487 Dual Wavelength Ultraviolet Detector. The columns are Aminex HPX-87H 300*7.8 mm columns (BioRad), used with a Security Guard cartridge holder (Phenomenex) and Carbo H+ guard cartridges (Phenomenex).

[0101] An Isocratic mobile phase of 10 mM H2SO4 in high-purity water, containing sodium azide (0.005%), filtered through an 0.45 micron filter, is used at a flow rate of 0.5 mL / min. The column temperature is 55° C. Sample injection volume is 20 pL. Each run is 60 minutes long. The internal temperature of the Refractive index detector is 35° C. 18.0 to 18.2 megaohm ultrapure water is used.

[0102] Standard Stock Solution 1 containing Glucose (0.1 g / L), Malic acid (0.1 g / L), Pyruvic acid (0.1 g / L), Arabitol (0.1 g / L), Succinic acid (0.1 g / L), Lactic acid (0.1 g / L), Glycerol (0. 1 g / L), and Acrylic acid (0. 1 g / L) in 10 mM H2SO4 is prepared. The stock solution is stored in a refrigerator and diluted 10: 1 with 10 mM H2SO4 solution to prepare the Standard 1 working solution for HPLC analysis. Standard 3HP (5 g / L) is prepared in 10 mM H2SO4 solution. This is the 3HP working standard solution for HPLC analysis. The limit of quantification for pyruvic acid using this method is 0.003 g / L.

[0103] For sample preparation, 0.25 grams of sample is weighed into a 25-ml volumetric flask and diluted with 10 mM sulfuric acid and filtered through a 0.45 micron nylon syringe filter. The wt. % of alcohols including glycerol, sugar alcohols, and sugars (e.g., polysaccharides and monosaccharides) are calculated using Refractive Index (RID) peak areas. The wt% of organic acids is calculated using UV peak area.

[0104] The phosphate, sulfate, and chloride ions are determined by measuring elemental phosphorous, sulfur, and chlorine by inductively coupled plasma atomic emission spectroscopy (ICP) analysis. Analysis is carried out using a Spectro Arcos FHS 12 instrument. All sulfur and phosphorous are assumed to be in the form of sulfate and phosphate ions, respectively.General Procedures3HP Fermentation Broth

[0105] 3HP broth produced by fermentation from glucose using a genetically modified yeast is used as the starting material for the processing steps. The fermentation broth contains 80 g / kg 3HP Equivalents in addition to other fermentation by-products including unfermented sugars, other organic acids such as lactic, pyruvic, succinic, and salts. Some of the major components are shown in Table 1 below.Table 1: Typical concentrations of major components of the aqueous 3HP fermentation broth.Filtration

[0106] The yeast biomass and other suspended solids are removed from the fermentation broth through filtration using a polymeric membrane element with 65 mil spacer and 20 kDa molecular weight cut-off pore size.Concentration

[0107] The clarified broth from filtration is concentrated to a 200 g / kg 3HP Equivalents solution in a forced circulation evaporator. The evaporator is operated at 65-75 °C and 200-300 mbar.Acidulation

[0108] The calcium in the broth is removed by adding concentrated H2SO4 until the pH of the broth solution is between 2. 1-2.3 forming an acidulated fermentation broth or acidulated solution. The precipitated gypsum is removed using centrifugation (1000 g for 5 minutes).Process Ion Exchange Unit Operation

[0109] The acidulated solution goes through a process ion exchange unit operation using both a cation exchange resin bed and an anion exchange resin bed in serial arrangement. Cation exchange is done using a strong acid cation exchange resin Amberlite FPC88, available from DuPont. The resin is loaded in a 6” internal diameter column with an approximate bed volume of 10 L. The column is conditioned by passing 30 L of 7% HC1 through the column followed by DI water until the effluent conductivity is <20 pS. The cation column is used to reduce the amounts of calcium, sodium, potassium, iron, magnesium and other metal ions, forming a reduced cation solution. The permeate is monitored for breakthrough of cations to determine when to begin rinse and regeneration of the resin bed. Breakthrough is identified when the concentration of magnesium in the permeate is >5 ppm or the concentration of potassium in the permeate is >10 ppm.

[0110] The reduced cation solution is then passed through the anion exchange resin bed or column. The anion exchange resin bed is a weak base anion exchange resin Amberlite FPA53, available from DuPont. The resin is loaded in a 6” internal diameter column with an approximate bed volume of 21 L. The column is conditioned by passing 63 L of 4% NaOH through the column followed by DI water until the effluent conductivity is <20 pS. The anion column is used to reduce the amounts of sulfate, phosphate, and chloride ions, and pyruvic acid to form a reduced ionsolution (depending on whether the anion column is operated on breakthrough of the strongly binding anions or the weakly binding anions). The permeate is monitored for breakthrough of anions to determine when to begin rinse and regeneration of the resin bed. Breakthrough is identified when the combined concentration of phosphorus and sulfur in the permeate is >100 ppm when the system is optimized for strongly binding anions. Breakthrough is identified when the concentration of pyruvic acid in the permeate is >0.2 g / kg when the system is optimized for pyruvic acid.Evaporation Concentration

[0111] The reduced ion solution or material is concentrated using a forced circulation evaporator to a 3HP equivalents concentration of 500-550 g / kg. The pressure is set to 200-300 mbar and the temperature increases from 60 to 80° C to form a concentrated reduced ion solution.Distillation

[0112] Distillation is carried out using a boiling tube evaporator (BTE) (operating as a rising film evaporator) on the concentrated reduced ion solution. Concentrated reduced ion solution is fed from the bottom of the distillation unit through 1.5” x 20’ tubes heated with steam on the shell side of the heat exchanger. An external condenser is operated at 4 °C to collect 3HP as a 3HP product. The substances in the feed that are not volatilized in the BTE are removed from the vapor / liquid separator via a bottoms collection system. The 3HP product leaving distillation is a distilled 3HP stream.Polishing Ion Exchange Unit Operation

[0113] The distilled 3HP stream goes through a polish ion exchange unit operation using at least an anion exchange resin bed and optionally a cation exchange resin bed in serial arrangement. The distilled 3HP stream is passed through the anion exchange resin bed or column. The anion exchange resin bed is a weak base anion exchange resin Amberlite FPA53, available from DuPont. The resin is loaded in a 6” internal diameter column with an approximate bed volume of 21 L. The column is conditioned by passing 63 L of 4% NaOH through the column followed by DI w ater until the effluent conductivity7is < 20 pS. The anion column is used to reduce the residual amounts of sulfate, phosphate, and chloride ions not removed by the process ion exchange unit operation or the distillation unit operation, and the majority7of pyruvic acid. The 3HP stream leaving the polish ion exchange unit operation is a 3HP product stream.

[0114] The permeate is monitored for breakthrough of anions to determine when to begin rinse and regeneration of the resin bed. Breakthrough is identified when the concentration of pyruvic acid in the permeate is >0.2 g / kg.

[0115] Optional cation exchange may be done using a strong acid cation exchange resin Amberlite FPC88, available from DuPont. This cation exchange resin bed preferably precedes the anion exchange resin bed. The cation exchange resin bed is loaded in a 6” internal diameter column with an approximate bed volume of 10 L. The column is conditioned by passing 30 L of 7% HC1 through the column followed by DI water until the effluent conductivity is <20 pS. The cation exchange column is used to reduce the amounts of any residual calcium, sodium, potassium, iron and magnesium present after distillation. If used, the cation exchange resin bed of the polish ion exchange unit will reduce the amount of metal ions, including metal ions released from stainless steel that may be contained in the fluid entering the polish ion exchange unit. Typically, metal ions are reduced to 20 mg or less per kilogram of 3HP Equivalents, preferably less than 10 mg per kilogram of 3HP Equivalents, and sometimes less than 5 mg per kilogram of 3HP Equivalents.

[0116] In the following examples, the feed rate, BTE operating temperature, and vacuum pressure are controlled. All pressures are absolute. Unless otherwise indicated, reported distillation temperatures are temperatures calculated from steam tables.Example 1

[0117] This Example utilizes the process ion exchange unit operation but not a polish ion exchange unit operation as illustrated in FIG. 2. This Example optimizes the process ion exchange unit operation for the reduction of phosphate and sulfate (operated on breakthrough of total phosphorus and sulfur in permeate of greater than 100 ppm).

[0118] The acidulated 3HP containing solution is processed through cation exchange with a strong acid cation resin (Amberlite FPC88) to minimize metal cations in the solution. The reduced cation solution is passed through a resin bed of weak base anion resin (Amberlite FPA53) at a flow rate of 3 bed volumes (BV) per hour. A total of 14 bed volumes of feed is processed before water rinse and subsequent regeneration of the resin bed. The anion exchange process is optimized to reduce total phosphorus and sulfur to less than 100 ppm in a 20% 3HP solution. The reduced ion solution is then evaporated to 55% 3HP and distilled to provide a purified 3HP solution.

[0119] Results for this Example are reported in Table 2 and Table 3 below.

[0120] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual organic acids (e.g., pyruvic acid) that aren’t removed from the purified 3HP solution via distillation typically reduce the yield of the dehydration reaction when dehydration is operated in continuous or semi-continuous mode.Example 2

[0121] This Example utilizes the process ion exchange unit operation but not a polish ion exchange unit operation as illustrated in FIG. 2. This Example optimizes the process ion exchange unit operation for the reduction of pyruvic acid (operated on breakthrough of pyruvic acid in permeate of greater than 0.2 g / kg).

[0122] The acidulated 3HP containing solution is processed through cation exchange with a strong acid cation resin (Amberlite FPC88) to minimize metal cations in the solution. The reduced cation solution is passed through a resin bed of weak base anion resin (Amberlite FPA53) at a flow rate of 3 bed volumes (BV) per hour. A total of 9.5 bed volumes of feed is processed before water rinse and subsequent regeneration of the resin bed. The anion exchange process is optimized to reduce pyruvic acid to <0. 1 g / kg in a 20% 3HP solution. The total phosphorus and sulfur are below 100 ppm in a 20% 3HP solution when anion exchange is optimized for pyruvic acid. The reduced ion solution is then evaporated to 55% 3HP and distilled to provide a purified 3HP solution. Optimization of anion exchange for pyruvic acid decreases the volume of feed prior to regeneration and therefore increases water consumption, regeneration chemical (4% sodium hydroxide) use, and wastewater treatment loading by >47% compared to the process in Example 1. The reduction of pyruvic acid is advantageous for an economical continuous or semi-continuous dehydration of a purified 3HP solution to acrylic acid.

[0123] Results for this Example are reported in Table 2 and Table 3 below.

[0124] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual organic acids (e.g., pyruvic acid, lactic acid, succinic acid) that aren’t removed from the purified 3HP solution via distillation typically reduce the yield of the dehydration reaction when dehydration is operated in continuous or semi-continuous mode.Example 3

[0125] This Example utilizes the process ion exchange unit operation but not a polish ion exchange unit operation as illustrated in FIG. 2. This Example optimizes the process ion exchangeunit operation for the reduction of lactic acid (operated on breakthrough of lactic acid in permeate of greater than 2 g / kg).

[0126] The acidulated 3HP containing solution is processed through cation exchange with a strong acid cation resin (Amberlite FPC88) to minimize metal ions in the solution. The reduced metal ions solution is passed through a resin bed of weak base anion resin (Amberlite FPA53) at a flow rate of 3 bed volumes (BV) per hour. A total of 2.5 bed volumes of feed is processed before water rinse and subsequent regeneration of the resin bed. The anion exchange process is optimized to reduce lactic acid to <1 g / kg in a 20% 3HP solution. The total phosphorus and sulfur are below 100 ppm in a 20% 3HP solution when anion exchange is optimized for lactic acid. The reduced ion solution is then evaporated to 55% 3HP and distilled to provide a purified 3HP solution. Optimization of anion exchange for lactic acid decreases the volume of feed prior to regeneration and therefore increases water consumption, regeneration chemical (4% sodium hydroxide) use, and wastewater treatment loading by >14% compared to the process in Example 2.

[0127] Results for this Example are reported in Table 2 and Table 3 below.

[0128] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual organic acids (e.g., pyruvic acid, lactic acid, succinic acid) that aren’t removed from the purified 3HP solution via distillation typically reduce the yield of the dehydration reaction when dehydration is operated in continuous or semi-continuous mode.Example 4

[0129] This Example utilizes the process ion exchange unit operation and the polish ion exchange unit operation as illustrated in FIG. 1. This Example optimizes the polish ion exchange unit operation for the reduction of pyruvic acid (operated on breakthrough of pyruvic acid in permeate of greater than 0.2 g / kg).

[0130] The acidulated 3HP containing solution is processed through cation exchange with a strong acid cation resin (Amberlite FPC88) to minimize metal ions in the solution. This reduced metal ions solution is passed through a resin bed of weak base anion resin (Amberlite FPA53) at a flow rate of 3 bed volumes (BV) per hour. A total of 14 bed volumes of feed is processed before water rinse and subsequent regeneration of the resin bed. The process anion exchange process is optimized to reduce total phosphorus and sulfur to less than 100 ppm in a 20% 3HP solution. The reduced ion solution is then evaporated to 55% 3HP and distilled to provide a distilled 3HP solution. The distilled 3HP solution is processed through a polishing anion exchange resin (Amberlite FPA53) to reduce residual organic acids in the distilled 3HP solution. The distilled3HP solution is passed through the polishing anion exchange resin bed at a flow rate of 3 BV / hr and optimized for pyruvic acid reduction. The polish ion exchange process is optimized to reduce pyruvic acid to less than 0.2 g / kg of permeate leaving the polish ion exchange process. This two- step anion removal process reduces water consumption, regeneration chemical (4% sodium hydroxide) use, and wastewater treatment loading by >29% compared to the process in Example 2 and 3.

[0131] Results for this Example are reported in Table 2, Table 3, and Table 4 below.

[0132] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual organic acids (e.g.. pyruvic acid, lactic acid, succinic acid) that aren’t removed from the purified 3HP solution via distillation typically reduce the yield of the dehydration reaction when dehydration is operated in continuous or semi-continuous mode.Example 5

[0133] This Example utilizes the process ion exchange unit operation and a polish ion exchange unit operation as illustrated in FIG. 1. This Example optimizes the polish ion exchange unit operation for the reduction of lactic acid (operated on breakthrough of lactic acid in permeate of greater than 2 g / kg).

[0134] The acidulated 3EIP containing solution is processed through cation exchange with a strong acid cation resin (Amberlite FPC88) to minimize metal ions in the solution. The reduced metal ions solution is passed through a resin bed of weak base anion resin (Amberlite FPA53) at a flow rate of 3 bed volumes (BV) per hour. A total of 14 bed volumes of feed is processed before water rinse and subsequent regeneration of the resin bed. The anion exchange process is optimized to reduce total phosphorus and sulfur to less than 100 ppm in a 20% 3HP solution. The reduced ion solution is then evaporated to 55% 3HP and distilled to provide a purified 3HP solution. The purified 3HP solution is processed through a polishing anion exchange resin (Amberlite FPA53) to reduce residual organic acids in the distillate. The polish ion exchange process is optimized to reduce lactic acid to less than 2 g / kg of permeate leaving the polish ion exchange process. The distilled 3HP solution is passed through the polishing anion exchange resin bed at a flow rate of 3 BV / hr and optimized for lactic acid reduction. A two-step anion removal process reduces water consumption, regeneration chemical (4% sodium hydroxide) use, and wastewater treatment loading by >26% compared to the process in example 2.

[0135] Results for this Example are reported in Table 2. Table 3, and Table 4 below.

[0136] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual organic acids (e.g.. pyruvic acid, lactic acid, succinic acid) that aren't removed from the purified 3HP solution via distillation typically reduce the yield of the dehydration reaction when dehydration is operated in continuous or semi-continuous mode.Table 2.Table 3.Table 4.Example 6 - Comparison of Distillation with and without the use of vapor impingement devices located in the 3HP Vapor pathDistillation Without Vapor Impingement Device:

[0137] A fermentation process with glucose and yeast is performed to generate a 3HP containing broth. The fermentation broth contains 83 g / kg 3HP equivalents, 7100 ppm residual monosaccharides and polysaccharides (trehalose, dextrose, fructose, sucrose, raffinose, maltose, maltotriose), and 1.2 g / kg pyruvic acid in addition to other residual monosaccharides and polysaccharides, sugar alcohols, salts, yeast biomass, and components of the fermentation media. A clarification is performed using ultrafiltration to remove suspended solids including the yeast biomass. The clarified solution undergoes a water removal step to give a concentrated solution of 200 g / kg 3HP equivalents, 17100 ppm monosaccharides and polysaccharides, and 2.9 g / kg pyruvic acid. A series of deashing steps is performed to remove calcium through an acidulation and filtration process. This is followed by treatment of the 3HP containing solution with cation and anion exchange resins. The 3HP containing solution is concentrated under reduced pressure to 550 g / kg 3HP equivalents, 47025 ppm monosaccharides and polysaccharides, and 5.8 g / kg pyruvic acid by removal of water in a forced circulation evaporator. A distillation process using a boiling tube evaporator with an open vapor path to the condenser is performed on the 3HP containing solution to reduce residual sugars. The purified distillate contains 530 g / kg 3HP equivalents, 515 ppm monosaccharides and polysaccharides (consisting of glucose, fructose, sucrose, trehalose, raffinose, maltose, and maltotriose), 455 ppm total sugar alcohols selected from the group consisting of xylitol, erythritol, arabitol, and mixtures thereof and 6.7 g / kg pyruvic acid. Total residual sugars content is 1830 mg based on a kilogram of 3HP Equivalents present.Distillation With Vapor Impingement Device:

[0138] Bio-produced 3HP purified by distillation with coalescer in vapor path. A fermentation process with glucose in yeast is performed to generate a 3HP containing broth. The fermentation broth contains 82 g / kg 3HP equivalents, 6800 ppm residual monosaccharides and polysaccharides (trehalose, dextrose, fructose, sucrose, raffinose, maltose, maltotriose), and 1.3 g / kg pyruvic acid in addition to other residual sugars, sugar alcohols, salts, yeast biomass, and components of the fermentation media. A clarification is performed using ultrafiltration to remove suspended solids including the yeast biomass. The clarified solution undergoes a water removal step to give a concentrated solution of 200 g / kg 3HP equivalents, 16590 ppm monosaccharides and polysaccharides, and 3.2 g / kg pyruvic acid. A series of deashing steps is performed to remove calcium through an acidulation and filtration process. This is followed by treatment of the 3HP containing solution with cation and anion exchange resins. The 3HP containing solution is concentrated under reduced pressure to 550 g / kg 3HP equivalents, 45620 ppm monosaccharides and polysaccharides, and 6.4 g / kg pyruvic acid by removal of water in a forced circulation evaporator. A distillation process using a boiling tube evaporator with chevrons aligned in the vapor path to the condenser is performed on the 3HP containing solution to reduce sugars. The purified distillate contains 530 g / kg 3HP equivalents, 52 ppm monosaccharides and polysaccharides, 43 ppm total sugar alcohols selected from the group consisting of xylitol, erythritol, arabitol, and mixtures thereof and 7.4 g / kg pyruvic acid. Total residual sugars content is 179 mg based on a kilogram of 3HP equivalents present.

[0139] As can be seen from this Example 6, the use of a vapor impingement device (for example chevrons) in the 3HP vapor path significantly reduces the total residual sugars in the final 3HP product.

[0140] The 3HP broth is processed using the ion exchange methods described herein for reducing pyruvic acid and the methods taught herein for reducing residual sugar content are used together to obtain a final 3HP product that has the residual sugar content described above (when a vapor impingement device (such as chevrons)) were used; and similar pyruvic acid content and processing parameters as described in examples 2 and 4.

[0141] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual organic acids (e.g., pyruvic acid) and residual sugars that aren’t removed from the purified 3HP solution via distillation typically reduce the yield of the dehydration reaction when dehydration is operated in continuous or semi-continuous mode.Example 7 - Use of cationic bed polish ion exchanger to reduce iron cations

[0142] This Example utilizes the process ion exchange unit operation and the polish ion exchange unit operation as illustrated in FIG. 1. This Example optimizes the polish ion exchange unit operation for the reduction of metal ions in a cation exchange resin bed (operated on breakthrough of metal ions in permeate of greater than 3 ppm) and the reduction of pyruvic acid in an anion exchange resin bed (operated on breakthrough of pyruvic acid in permeate of greater than 0.2 g / kg).

[0143] The acidulated 3HP containing solution is processed through cation exchange with a strong acid cation resin (Amberlite FPC88) to minimize metal cations in the solution. This reduced cation solution is passed through a resin bed of weak base anion resin (Amberlite FPA53) at a flow rate of 3 bed volumes (BV) per hour. A total of 14 bed volumes of feed is processed before water rinse and subsequent regeneration of the resin bed. The process anion exchange process is optimized to reduce total phosphorus and sulfur to less than 100 ppm in a 20% 3HP solution. The reduced ion solution is then evaporated to 55% 3HP and distilled to provide a distilled 3HP solution. The distilled 3HP solution is processed through a polishing cation exchange resin (Amberlite (FPC88) to reduce total metal ions to less than 3 ppm of permeate leaving the polish cation exchange process. The distilled 3HP solution is passed through the polishing cation exchange resin bed at a flow rate of 3 BV / hr and optimized for reduction of metal ions. The cation exchange polished 3HP solution is processed through a polishing anion exchange resin (Amberlite FPA53) to reduce residual organic acids in the polish ion exchange permeate. The cation exchange polished 3HP solution is passed through the polishing anion exchange resin bed at a flow rate of 3 BV / hr and optimized for pyruvic acid reduction. The polish anion exchange process is optimized to reduce pyruvic acid to less than 0.2 g / kg of permeate leaving the polish ion exchange process. The iron cation content based on a kilogram of 3HP present is 6 mg.

[0144] The 3HP broth of this Example 7 is also processed using vapor impingement devices, such as described in Example 6, the final 3HP product has residual sugar content similar to described in Example 6.

[0145] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual iron, residual organic acids (e.g., pyruvic acid) that aren’t removed from the purified 3HP solution via distillation typically reduce the yield of the dehydration reaction when dehydration is operated in continuous or semi-continuous mode.Example 8 - Impact of Saccharides and Organic Acids on Polymer FormationMethod for analyzing polymer concentration

[0146] The polymer in the reaction mixture is a complex mixture of polyacrylic acid and polyesters formed from 3HP and trace amounts of other organic acids and saccharides that are present in the 3HP solution. The polymer concentration refers to the concentration of the polyacrylic acid obtained after hydrolyzing the esters in the reaction mixture with an aqueous solution of NaOH. Specifically, ten times the amount of a 10 t% aqueous NaOH solution, relative to a sample of the reaction mixture, is added to the sample and heated at 80°C for 1 hour to hydrolyze the esters.

[0147] The solution is then subjected to gel permeation chromatography (GPC) under the following conditions:

[0148] Columns: A combination of TSKgel G3000PWxl, TSKgel G2500PWxl (manufactured by Tosoh Co., Ltd.)

[0149] Eluent: Water / Disodium hydrogen phosphate / Sodium dihydrogen phosphate in a98: 1 : 1 (weight ratio).

[0150] Detector: RI

[0151] Column temperature: 50°C

[0152] A calibration curve is prepared with known amounts of polyacrylic acid standard solutions and calculated using the refractive index (RID) peak area with a retention time of molecular weight of 800 or more.Source of 3HP

[0153] 3HP fermentation broth was obtained by fermentation from glucose using genetically modified yeast. The 3HP equivalent of the obtained 3HP fermentation broth was about 80 g / kg, and it also contained unfermented sugars, sugar alcohols such as glycerin, other organic acids such as lactic acid and pyruvic acid, and fermentation by-products such as salts. The obtained 3HP fermentation broth was filtered through a polymer membrane to remove yeast and other suspended solids. The obtained 3HP filtered fermentation broth was concentrated to about 200 g / kg of 3HP equivalent solution in a forced circulation evaporator. Concentrated sulfuric acid was added to the concentrated 3HP filtered fermentation broth to pH 2.1-2.3, and calcium in the fermentation broth was precipitated and removed as gypsum (calcium sulfate) to obtain an acidified 3HP fermentation broth.

[0154] The acidified 3HP fermentation broth was passed through a strong acidic cation exchange resin column (DuPont Amberlite FPC88) to obtain a low-cation 3HP solution with a reduced amount of cations such as calcium, sodium, iron, and magnesium.

[0155] Subsequently, the low-cation 3HP solution was passed through a weakly basic anion exchange resin column (DuPont Amberlite FPA53) to obtain a low-ion 3HP aqueous solution in which the amount of anions such as sulfate ion, phosphate ion. chloride ion and pyruvate was reduced.

[0156] In the ion exchange step, the amount of each ion in the column permeate is monitored, and when the concentration exceeds the set concentration, the ion exchange resin column is regenerated and rinsed. In the anion exchange resin column, the total concentration of sulfate and phosphate ions is usually monitored at <100ppm, and the amount of pyruvate contained in the low ion 3HP solution obtained in this case is about 5 g / kg. When preparing the low pyruvate 3HP solution, the amount of pyruvate in the column permeate was monitored, and the anion exchange resin column was regenerated and rinsed within a range not exceeding a predetermined concentration.

[0157] The obtained low ion 3HP solution was concentrated to a 3HP equivalent concentration of 500-700 g / kg using a forced circulation evaporator, and then distilled using a wiped film evaporator (WFE) to obtain a 3HP solution with reduced high boiling point impurities such as unfermented sugars. The amount of sugars in the 3HP solution after the distillation step is about 1.5 g / kg under normal fermentation and rectification conditions. When the low sugar 3HP solution was prepared, the amount of treatment, temperature and pressure were adjusted.

[0158] The 3HP solution obtained by distillation was concentrated to a water content of 20wt% or less using a forced circulation evaporator to obtain the 3HP solution used for the dehydration reaction.

[0159] The 3HP solutions in Table 5 below containing different amounts of pyruvate and saccharides are obtained by changes in the fermentation and downstream process conditions. In addition, Sample 8-3 w as prepared by adding extra lwt% glucose to a 3HP solution to determine the impact excess saccharides in a 3HP solution have on the dehydration reaction. Similarly, Sample 8-4 was prepared by adding extra lwt% glycerol to a 3HP solution.Dehydration of 3HP to Acrylic acid

[0160] The apparatus shown in FIG. 5 is assembled, and 158 g of a 3HP solution (Sample 8-1), 20 g of potassium hydroxide as the catalyst, and 0.10 g of iron acetate as a polymerizationinhibitor are added to the reactor. The pressure inside the reactor is reduced to 10 kPa. and the reaction flask heated to 150°C utilizing an oil bath. The remaining 3HP solution is then supplied to the reactor at a rate of 2.4 g / min at the reaction temperature of 150°C. Air is also supplied to the gas phase in the reactor at a rate of 3 L / hr.

[0161] A mixture of the vaporized reaction product and air leaving the reactor is passed through a condenser, and the condensed aqueous acrylic acid solution is collected in a receiver. A certain amount of reaction mixture is always present in the reactor. Table 5 shows the amount of reaction mixture and the amount of polymer in the reactor after 7 hours of reaction. The polymer concentration in this reaction mixture was determined using the method described above.

[0162] The same procedure as described for Example 8-1 is repeated using Samples 8-2 to 8-4. Table 5 shows the impact of pyruvic acid, saccharides, and glycerol on the amount of polymer formed in the reaction after 7 hours of reaction.Table 5.

[0163] Example 8-2 demonstrates the higher amount of polymer that is formed when there is an excess of Pyruvic acid. Example 8-3 demonstrates the higher amount of polymer that is formed when there is an excess of Saccharides. Example 8-4 demonstrates that excess glycerol does not have a significant impact on the formation of polymers.

[0164] All patents, patent applications (including provisional applications), and publications cited herein are incorporated by reference as if individually incorporated for all purposes. Unless otherwise indicated, all parts and percentages are by weight and all molecular weights are weight average molecular weights. The foregoing detailed description has been givenfor clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.

Claims

CLAIMS1 . A method of recovering 3-hydroxypropionic acid from a fermentation broth, the method comprising the steps of: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration; acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3- hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3- hydroxypropionic acid: reducing an ion concentration in the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3-hydroxypropionic acid; removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3 HP vapor path to form a distilled 3HP stream having reduced residual sugar content and a bottoms stream; and removing pyruvic acid from the distilled 3HP stream with a polish ion exchange unit operation to form a 3HP product stream.

2. The method of claim 1, wherein the 3HP product stream has less than 1059 mg total residual sugars per kilogram of 3HP equivalents, or less than 824 mg total residual sugars per kilogram of 3HP equivalents, or less than 588 mg total residual sugars per kilogram of 3HP equivalents, or less than 353 mg total residual sugars per kilogram of 3HP equivalents, or less than 176 mg total residual sugars per kilogram of 3HP equivalents and less than 1.5 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 1 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents, orless than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.1 gram of pyruvic acid per kilogram of 3HP equivalents.

3. The method of claim 1 or 2, wherein the acidified solution comprises greater than 5 grams of pyruvic acid per kilogram of 3HP equivalents, or greater than 10 grams of pyruvic acid per kilogram of 3HP equivalents.

4. The method of any preceding claims, wherein the vapor impingement device is selected from the group comprising chevrons, box filters, demister pads, and structured packing.

5. The method of any preceding claims, wherein the process ion exchange unit operation comprises a bed of cation exchange resin and a bed of anion exchange resin in series.

6. The method of any preceding claims, wherein the polish ion exchange unit operation comprises a bed of anion exchange resin.

7. The method of any preceding claims, wherein the polish ion exchange unit operation comprises a bed of cation exchange resin upstream from the bed of anion exchange resin.

8. The method of any preceding claims, wherein the process ion exchange unit operation removes at least 90% of total phosphate and sulfate ions from the acidified solution.

9. The method of any preceding claims, wherein the process ion exchange unit operation removes from 10% to 70% pyruvic acid from the acidified solution.

10. The method of any preceding claims, wherein the polish ion exchange unit operation removes at least 90% of pyruvic acid from the distilled 3HP stream.

11. The method of any preceding claims, wherein the polish ion exchange unit operation removes at least 95% of pyruvic acid from the distilled 3HP stream.

12. The method of any preceding claims, wherein the vapor impingement device comprises chevrons.

13. The method of any preceding claim, wherein the 3HP product stream has at least 55% by weight 3HP equivalents, or at least 60% by weight 3HP equivalents, or at least 65% by weight 3HP equivalents, or at least 70% by weight 3HP equivalents.

14. The method of any preceding claim, further comprising concentrating the 3HP product stream to at least 80% by weight 3HP equivalents, or at least 85% by weight 3HP equivalents, or at least 90% by weight 3HP equivalents, forming a concentrated 3HP product.

15. The method of claim 14, wherein concentrating comprises evaporating the 3HP product stream to form the concentrated 3HP product.

16. A method of recovering 3-hydroxypropionic acid from a fermentation broth, the method comprising the steps of: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration; acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3- hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3- hydroxypropiomc acid: reducing an ion concentration and pyruvic acid in the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3- hydroxypropionic acid: removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3 HP vapor path to form a distilled 3HP stream and a bottoms stream; wherein the distilled 3HP stream forms a 3HP product stream having reduced residual sugar content and the 3HP productstream has less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents, or less than 1 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.1 gram of pyruvic acid per kilogram of 3HP equivalents.

17. The method of claim 16, wherein the acidified solution comprises greater than 5 grams of pyruvic acid per kilogram of 3HP equivalents, or greater than 10 grams of pyruvic acid per kilogram of 3HP equivalents.

18. The method of any of claims 16 or 17, wherein the 3HP product stream has less than 1059 mg total residual sugars per kilogram of 3HP equivalents, or less than 824 mg total residual sugars per kilogram of 3HP equivalents, or less than 588 mg total residual sugars per kilogram of 3HP equivalents, or less than 353 mg total residual sugars per kilogram of 3HP equivalents, or less than 176 mg total residual sugars per kilogram of 3HP equivalents.

19. The method of any of claims 16 to 18, wherein the process ion exchange unit operation comprises a bed of cation exchange resin and a bed of anion exchange resin in series, and wherein the bed of cation exchange resin is located upstream of the bed of anion exchange resin.

20. The method of any of claims 1 to 19, wherein the process ion exchange unit operation removes at least 90% of total phosphate and sulfate ions from the acidified solution.

21. The method of any of claims 16 to 20. wherein the process ion exchange unit operation removes at least 90% of pyruvic acid from the acidified solution.

22. The method of any of claims 16 to 21, wherein the residual sugars comprise monosaccharides, polysaccharides and sugar alcohols consisting of the group consisting of arabitol, erythritol, xylitol, and mixtures thereof.

23. The method of any of claims 16 to 22, wherein the 3HP product stream has at least 55% by weight 3HP equivalents, or at least 60% by weight 3HP equivalents, or at least 65% by weight 3HP equivalents, or at least 70% by weight 3HP equivalents.

24. The method of any of claims 16 to 23, further comprising concentrating the 3HP product stream to at least 80% by weight 3HP equivalents, or at least 85% by weight 3HP equivalents, or at least 90% by weight 3HP equivalents, forming a concentrated the 3HP product.

25. The method of claim 24. wherein concentrating comprises evaporating the 3HP product stream to form the concentrated the 3HP product.

26. A method of recovering 3-hydroxypropionic acid from a fermentation broth, the method comprising the steps of: providing a fermentation broth having a pH of from about 2 to about 6 (or 3 to 5) and comprising 3-hydroxypropionic acid or salts thereof, and a calcium ion concentration; acidifying the fermentation broth with sulfuric acid to lower the pH to form an acidified fermentation broth with a pH from about 1 to about 3 comprising 3- hydroxypropionic acid and produce an isolatable material comprising a calcium sulfate compound; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to produce an acidified solution comprising 3- hydroxypropionic acid; reducing an ion concentration in the acidified solution with a process ion exchange unit operation to produce a reduced ion solution comprising 3-hydroxypropionic acid, the process ion exchange unit comprising at least a first anion exchange resin bed and a second anion exchange resin bed, the first anion exchange resin bed removing anions until the reduced ion solution reaches 100 ppm total phosphorus and sulfur concentration, then the second anion exchange resin bed begins removing anions and the first anion exchange resin bed is regenerated; removing water from the reduced ion solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight; distilling the distillation feed stream at a distillation temperature value and distillation pressure value with a vapor impingement device in the 3 HP vapor path to form a distilled 3HP stream having reduced residual sugar content and a bottoms stream; andremoving pyruvic acid from the distilled 3HP stream with a polish ion exchange unit operation to form a 3HP product stream, the polish ion exchange unit comprising at least a first anion exchange resin bed and a second anion exchange resin bed, the first anion exchange resin bed removing pyruvic acid until the 3HP product stream reaches 0.2 g / kg pyruvic acid concentration off the first anion exchange resin bed, then the second anion exchange resin bed begins removing pyruvic acid and the first anion exchange resin bed is regenerated.

27. The method of claim 26, wherein the process ion exchange unit comprises at least a first anion exchange resin bed, a second anion exchange resin bed, and a third anion exchange resin bed, the first anion exchange resin bed and the second anion exchange resin bed removing anions until the reduced ion solution reaches 100 ppm total phosphorus and sulfur concentration off the first anion exchange resin bed, then the third anion exchange resin bed begins removing anions and the first anion exchange resin bed is regenerated.

28. The method of claim 26 or 27, wherein the polish ion exchange unit comprises at least a first anion exchange resin bed, a second anion exchange resin bed, and a third anion exchange resin bed, the first anion exchange resin bed and the second anion exchange resin bed removing pyruvic acid until the reduced ion solution reaches 0.2 g / kg pyruvic acid concentration off the first anion exchange resin bed, then the third anion exchange resin bed begins removing pyruvic acid and the first anion exchange resin bed is regenerated.

29. The method of claim 26, 27, or 28. wherein the 3HP product stream has less than 1076 mg total residual sugars per kilogram of 3HP equivalents, or less than 824 mg total residual sugars per kilogram of 3HP equivalents, or less than 588 mg total residual sugars per kilogram of 3HP equivalents, or less than 353 mg total residual sugars per kilogram of 3HP equivalents, or less than 176 mg total residual sugars per kilogram of 3HP equivalents.

30. The method of any of claims 26 to 29, wherein the 3HP product stream has less than 1 .5 grams of pyruvic acid per kilogram of 3HP equivalents, or less than 1 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.5 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0.25 gram of pyruvic acid per kilogram of 3HP equivalents, or less than 0. 1 gram of pyruvic acid per kilogram of 3HP equivalents.

31. The method of any of claims 26 to 30. wherein the acidified solution comprises greater than 5 grams of pyruvic acid per kilogram of 3HP equivalents, or greater than 10 grams of pyruvic acid per kilogram of 3HP equivalents.

32. The method of any of claims 26 to 31. wherein the residual sugars comprise monosaccharides, polysaccharides and sugar alcohols consisting of the group consisting of arabitol, erythritol, xylitol, and mixtures thereof.

33. The method of any of claims 26 to 32, wherein the 3HP product stream has at least 55% by weight 3HP equivalents, or at least 60% by weight 3HP equivalents, or at least 65% by weight 3HP equivalents, or at least 70% by weight 3HP equivalents.

34. The method of any of claims 26 to 33, further comprising concentrating the 3HP product stream to at least 80% by weight 3HP equivalents, or at least 85% by weight 3HP equivalents, or at least 90% by weight 3HP equivalents, forming a concentrated 3HP product.

35. A composition comprising 3-hydroxypropionic acid (3HP) derived from fermentation of starch hydrolysate, the composition comprising: i) At least 85 wt% 3HP equivalents derived from producing 3HP by fermentation; ii) Less than 400 ppm total monosaccharides and polysaccharides; iii) Less than 500 ppm total sugar alcohols selected from the group consisting of erythritol, xylitol, arabitol, and mixtures thereof; and iv) less than 1000 ppm pyruvic acid.

36. The composition of claim 35, wherein the composition comprises less than 500 ppm pyruvic acid.

37. The composition of any of claims 35 and 36, wherein the composition comprises less than 300 ppm total monosaccharides and polysaccharides.

38. The composition of any of claims 35 and 36, wherein the composition comprises less than 200 ppm total monosaccharides and polysaccharides.

39. The composition of any of claims 35 and 36, wherein the composition comprises less than 100 ppm total monosaccharides and polysaccharides.

40. The composition of any of claims 35 and 36, wherein the composition comprises less than 50 ppm total monosaccharides and polysaccharides.

41. The composition of any of claims 35-40, wherein the composition comprises less than 300 ppm pyruvic acid.

42. The composition of any of claims 35-41, wherein the composition comprises less than 400 ppm total sugar alcohols selected from the group consisting of erythritol, xylitol, arabitol, and mixtures thereof.

43. The composition of any of claims 35-41. wherein the composition comprises less than 300 ppm total sugar alcohols selected from the group consisting of erythritol, xylitol, arabitol, and mixtures thereof.

44. The composition of any of claims 35-41, wherein the composition comprises less than 200 ppm total sugar alcohols selected from the group consisting of erythritol, xylitol, arabitol, and mixtures thereof.

45. The composition of any of claims 35-41, wherein the composition comprises less than 100 ppm total sugar alcohols selected from the group consisting of erythritol, xylitol, arabitol, and mixtures thereof.

46. The composition of any of claims 35-41, wherein the composition comprises less than 50 ppm total sugar alcohols selected from the group consisting of erythritol, xylitol, arabitol, and mixtures thereof.

47. The composition of any of claims 35-46, wherein the composition further comprises less than 1000 ppm lactic acid.

48. The composition of any of claims 35-46, wherein the composition further comprises less than 500 ppm lactic acid.

49. The methods of any of claims 1 -34, wherein saccharification enzymes are used during the production of the broth comprising 3HP to reduce the amount of residual sugars in the fermentation broth.

50. The method of claim 49, wherein the saccharification enzymes convert non-fermentable sugars into fermentable sugars that can be used by a fermentation organism utilized to produce 3HP.

51. The method of any of claims 49 and 50, wherein the saccharification enzymes are selected from the group consisting of glucoamylase, transglucosidase, alpha-amylase, and mixtures thereof.

52. The method of any of claims 49 and 50, wherein the saccharification enzymes is selected from the group comprising glucoamylase, transglucosidase, or mixtures thereof.

53. The method of any of claims 39 and 50, wherein the saccharification enzyme comprises glucoamylase.

54. The 3HP product stream of any of claims 1-34, or the composition of claims 35-53, wherein the metal ions content is less than 20 ppm.

55. The 3HP product stream of any of claims 1-34, or the composition of claims 35-53, wherein the metal ions content is less than 10 ppm.

56. The 3HP product stream of any of claim 1-34. or the composition of claims 35-53, wherein the metal ions content is less than 5 ppm.

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