Recovery of 3-hydroxypropionic acid with reduced metals IONS and / or organic acid content

Abstract

Methods of forming a concentrated 3HP solution includes removing organic acid and metal ions contamination with an ion exchange unit operation. 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 METALS IONS AND / OR ORGANIC ACID CONTENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 632.596, 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. Separations and systems that are suitable for use on the lab bench may not be feasible for use at commercial production levels, and introduction of different techniques on scale-up introduce new challenges and unexpected results.

[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 acry lic acid, orcombinations thereof. Processing streams having higher 3HP concentrations often include organic acid contaminants and higher than desirable metal ions concentrations that are difficult to separate from the 3HP. These organic acid contaminants (and metal ions) may be problematic when further processing the concentrated 3HP product. The present invention provides an advantageous process for recovery of concentrated 3HP with reduced organic acid contamination and reduced metal ion concentration.

[0006] Methods of forming a concentrated 3HP solution with reduced concentration of metal ions and optionally reduced organic acids contamination includes utilizing an ion exchange unit operation that selectively removes metal ions from the 3HP recovery process and optionally unwanted organic acids from the 3HP recovery process.

[0007] The 3HP recovery process preferably includes 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 metal ions concentration and preferably reduced organic acids concentration results from the use of both anion exchange resin beds and cation exchange resin beds in both the process ion exchange unit operation and the polish ion exchange unit operation.

[0008] The 3HP recovery process typically includes a process ion exchange unit operation upstream from a final 3HP distillation unit operation. The final concentrated 3HP product with reduced metal ions content and preferably reduced organic acids contamination results from the use of both cation exchange resins beds and anion exchange resin beds in the polishing ion exchange unit operation.

[0009] Metal ions may be present in the 3HP product due to their use in the fermentation and / or treatment of the 3HP containing broth. Additionally, metal ions may be released from metals in contact with the aqueous 3HP being processed in the various pieces of equipment used in downstream processing of 3-hydroxypropionic acid, which is acidic (pKa of 4.2). Metals like stainless steel and the like can be more susceptible to metal ions including iron, nickel, molybdenum, and chromium leaching out when exposed to high temperatures and low pHs. Therefore, ion exchange operations to remove metal ions preferably are carried out after the distillation unit operations, where temperatures may be their highest and pHs may be very low. Additionally, storage tanks prior to the final 3HP product storage tank (for example, storage tanks after the distillation step and prior to the final 3HP product storage tank).

[0010] Pyruvic acid is an organic acid that is considered an organic acid contaminant in 3HP. Pyruvic acid (formed during fermentation) mav be present in the 3HP stream feeding theprocess 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 gram 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).

[0011] 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 recovery system.

[0012] 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 recovery system.

[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- 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 to form a distilled 3HP stream and a bottoms stream;removing metal ions and preferably pyruvic acid from the distilled 3HP stream with a polish ion exchange unit operation to form a 3HP product stream; and optionally removing water from the 3HP product stream to form a composition having a 3-hydroxypropionic acid concentration of 50% to 99.9% (60% to 99.8%, 70% to 99.7%, 80% to 99.6%, and 90% to 99.5%). (Alternatively say >50% by weight, >70%, >80%, >90%, and >99.5%)

[0014] The method will preferably reduce metal ions in the 3HP product stream to less than <20 mg per kilogram of 3HP Equivalents, or less than 10 mg per kilogram of 3HP Equivalents, or less than 5 mg per kilogram of 3HP Equivalents, or less than 1 mg per kilogram of 3HP Equivalents, and reduce pyruvic acid in the 3HP product stream to less than 1.5 gram 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] Utilizing weak base anion exchange resin in both the process ion exchange and the polish ion exchange elfectively and efficiently removes organic acid contaminants in the process stream to recover the 3HP product stream.

[0016] In further aspects, 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 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 form 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 sulfurconcentration, 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 to form a distilled 3HP stream and a bottoms stream; and removing metal ions and 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 cation exchange resin bed and a second cation exchange resin bed, the first cation exchange resin bed removing metal ions, (e g., Na, K, Ca, Cu, Fe, Mg, Mn, Zn, Ni, Cr, and / or Mo) until the 3HP product stream reaches a desirable concentration (for example 20 ppm, or 10 ppm or 5 ppm of metal ions), then the second cation exchange resin bed begins removing metal ions and the first cation exchange resin bed is regenerated; preferably, the polish ion exchange unit further comprises 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, then the second anion exchange resin bed begins removing pyruvic acid and the first anion exchange resin bed is regenerated.

[0017] The process ion exchange unit operation typically includes at least three cation exchange resin beds and at least three anion exchange resin beds. Each of cation exchange resin beds and the anion exchange resin beds run in a lead-lag configuration (as described in more detail below). The anion exchange resin beds typically 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. The cation exchange resin beds typically include at least a first cation exchange resin bed, a second cation exchange resin bed, and a third cation exchange resin bed. The first cation exchange resin bed and the secondcation exchange resin bed removing cations until the reduced ion solution reaches 10 ppm total potassium concentration (breakthrough) off the first cation exchange resin bed. Then the cation exchange resin beds are operated similarly as described above for the anion exchange beds, except being operations to reduce the total potassium concentration.

[0018] Typically, the polish ion exchange unit operation 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.

[0019] Typically, the polish ion exchange bed is operated to significantly reduce the concentration of metal ions in the final 3HP product to the concentration described herein. The polish ion exchange unit operation typically includes at least three cation exchange resin beds in a lead-lag configuration. The cation exchange resin beds typically includes at least a first cation exchange resin bed, a second cation exchange resin bed, and a third cation exchange resin bed, the first cation exchange resin bed and the second cation exchange resin bed removing iron cations until the reduced ion solution reaches the desired maximum metal ions concentration (for example 20 ppm, or 10 ppm, or 5 ppm or 1 ppm) off the first cation exchange resin bed, then the third cation exchange resin bed begins removing metal ions and the first cation exchange resin bed is regenerated. These cation exchange resin beds are continuously operated in this manner so that at least two cation exchange resin beds are removing metal ions while the third or remaining cation exchange resin bed is regenerated and on stand-by until the cation exchange resin bed in operation experiences breakthrough.

[0020] The method is preferably operated to efficiently and effectively reduce metal ions to less than 20 mg per kilogram of 3HP Equivalents, or less than 10 mg per kilogram of 3HP Equivalents, or less than 5 mg per kilogram of 3HP Equivalents, or less than 1 mg per kilogram of 3HP Equivalents; and preferably efficiently and effectively reduce pyruvic acid in the 3HP product stream to less than 1.5 gram of pyruvic acid ner kilogram of 3HP equivalents, or less than1 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.

[0021] ‘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-hydroxypropionic acid present; and 3HP Equivalents concentration refers to the total concentration 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 (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.

[0022] 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.

[0023] 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

[0024] 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:

[0025] FIG. 1 is a process flow diagram of the present disclosure.

[0026] FIG. 2 is a process flow diagram of an ion exchange system without a polishing ion exchanger downstream of the distillation step.DETAILED DESCRIPTION

[0027] 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 andunderstanding by others skilled in the art of the principles and practices of the present invention can be facilitated.

[0028] All pressure measurements are reported as absolute pressures.

[0029] 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 high purity 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 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 acry lic acid, acry lic 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 and lactic acid.

[0030] Metal ions contamination in the 3HP product may reduce the yield for down stream processing using 3HP product streams as a feedstock. For example, metal ions may interfere with catalysts utilized to convert 3HP to other organic compounds and may catalyze the reaction of 3HP with other compounds present, such as polyols, alcohols, sugar alcohols and saccharides. For example, metal ions may interfere with the conversion of 3HP to acrylic acid and may further interfere with further processing of acrylic acid into other materials, such as esters and polymers. This may reduce the yield of the desired product being made or result in additional processing steps being needed to remove the metal ions effectively.

[0031] Organic acid contamination, such as pyruvic acid, may reduce the yield of 3HP reaction products for downstream processors using the 3HP product stream as a feedstock. Organic acids (other than 3HP) not removed from the 3HP product stream are problematic to the conversion of 3HP to acrylic 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 acrylic acid and are undesirable.

[0032] 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 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 improving overall recovery of 3-HP Equivalents utilizing the orocess described herein. Storing 3HPsolutions, pre-distillation, containing greater than 20 wt% 3HP Equivalents at room temperature (24 degrees Celsius) is preferably limited to less than 2 weeks, or less than 1 week. Storing 3HP solutions containing greater than 50 wt% 3HP Equivalents at room temperature (24 degrees Celsius) is preferably limited to less than 1 week, or less than 5 days or less than 80 hours or preferably less than 30 hours 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 acrylic acid, acrylic acid oligomers, or homo-oligomers of 3HP. Storing 3HP solutions, post-distillation, may or may not follow the above description based on whether the further processing tolerates increased amounts of acrylic acid, acrylic acid oligomers, or homooligomers of 3HP.

[0033] It is challenging to reduce and / or remove metal ions from 3HP process streams, especially streams that have low pH levels and high heat. Since high heat and low pH can cause leaching of metal ions, for example Na, K, Ca, Cu, Fe, Mg, Mn, Zn, Ni, Cr, and / or Mo ions into the 3HP process streams, it is important to remove metal ions from the 3HP processing after the 3HP has been distilled.

[0034] It is challenging to remove organic acid contaminants such as pyruvic acid from the 3HP process streams. Evaporation or distillation fails to efficiently separate pyruvic acid and / or lactic acid from the 3HP while separating some sugar and other heavy boilers from 3HP. Pyruvic acid carries over with 3HP as overhead product in evaporation or distillation unit operations, making separation of pyruvic acid from the 3HP difficult since it tends to concentrate as 3HP concentrates with liquid-vapor separation unit operations.

[0035] The present disclosure provides an advantageous process for recovery of concentrated 3HP with low levels of metal ion contaminants and also low levels of organic acid contaminants by utilizing more than one ion exchange unit operation. It is difficult and inefficient to achieve less than 5 ppm or less than 1 ppm metal ions in the concentrated 3HP distillate using a process consisting of cation and anion exchange before distillation and without cation and anion exchange after distillation. In particular, one or more cation and anion exchange unit operations may be configured to selectively remove contaminants from the 3HP being processed before a distillation step and then remove contaminants such as metal ion and organic acid contaminants, such as pyruvic acid from the 3HP process streams after a distillation unit operation.

[0036] Preferably, methods utilizing both anion exchange and cation exchange both before and after a distillation unit operation are provided for recovering a concentrated composition of3-hydroxypropionic acid having reduced metal ion concentration and reduced pyruvic acid concentration from a fermentation broth comprising: providing a fermentation broth 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 calcium sulfate; separating the isolatable material from the acidified fermentation broth comprising 3- hydroxypropionic acid to form 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 to form a distilled 3HP stream and a bottoms stream; and removing metal ions and pyruvic acid from the distilled 3HP stream with a polish ion exchange unit operation to form a 3HP product stream.

[0037] The 3HP product stream typically has less than 20 mg metal ions per kilogram 3HP Equivalents and typically has less than 1.5 grams of pyruvic acid per kilogram of 3HP equivalents (1500 mg). The 3HP product stream preferably has less than 10 mg metal ions per kilogram 3HP Equivalents and preferably 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) and less than 5 mg metal ions per kilogram 3HP Equivalents. 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).

[0038] 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.

[0039] The method may further include concentrating the 3HP product stream to at least 80% by weight 3HP equivalents, or at least 85% bv 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.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] 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.

[0044] 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 phosphorous species such as phosphate. As used herein the term ‘sulfur’ refers to any form of anionic sulfur species such as sulfate.

[0045] Thus, organic acids ‘breakthrough’ before chloride, phosphorus, and sulfur ‘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.

[0046] 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).

[0047] The polish ion exchange unit operation includes a bed of anion exchange resin. The polish ion exchange unit operation also includes a bed of cation exchange resin upstream from the bed of anion exchange resin to remove metal ions (such as sodium, potassium, calcium, copper, iron, magnesium, nickel, chromium, manganese)). 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.

[0048] 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, results in less chemical and water consumption than a single unit operation that reduces all anions. And, as set forth earlier, the use of a cation exchange resin bed downstream of distillation helps remove metal ions that were not efficiently removed during the process ion exchange operation, and may also come from the equipment used during downstream operations.

[0049] The process ion exchange unit operation may remove 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 may remove 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).

[0050] 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 at least 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). The polish ion exchange unit operation may remove at least 75% of metal ions from the distilled 3HP stream (when the polish ion exchange unit operation is operated to breakthrough of the potassium ions). Monovalent cations, such as potassium, has lower affinity to many cation exchange resin and therefore is the first cation type found in the permeate.

[0051] 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.

[0052] 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. After completion of the fermentation, various ionic species are present that are desirable to remove.

[0053] 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 w aler from the fermentation broth; an acidulation step (4) to lower the pH of the fermentation broth and precipitate and remove a calcium salt from the fermentation broth at step (5); 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.

[0054] 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 to form an aqueous solution with a pH from about 1 to about 3 comprising 3HP and produce an isolatable material comprising calcium, preferably a calcium sulfate compound; separation of the calciumsulfate compound from the aqueous solution comprising 3HP; 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.

[0055] 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.

[0056] 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 tank or piping) is less than 24 hours, or less than 12 hours, or less than 6 hours, preferably less than 60 minutes, or less than 50 minutes, or less than 40 minutes, or less than 30 minutes, at less than 80 degrees Celsius, or less than 75 degrees Celsius, or less than 70 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.

[0057] 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 less than 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 acry lic acid per one hundred parts by weight 3HP equivalents.

[0058] 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 of3HP 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.

[0059] Referring to FIG. 1 step (1) of the present process, a fermentation broth is provided having a pH of from 2 to 6, typically 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.

[0060] 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.

[0061] 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 centrifuging the fermentation broth.

[0062] 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.

[0063] The increase of concentration of 3HP in this step is particularly advantageous in providing an economic process. This also enables a more efficient removal of calcium in the subsequent acidulation and gypsum removal step. 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.

[0064] Referring to FIG. 1 step (4) of the present process, the fermentation broth is acidified to lower the pH to form an aqueous solution with a pH from about 1 to about 3 and 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 recovery7of 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.

[0065] 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 carry ing out 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 by lowering 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 will include 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. 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. The aqueous solution resulting from this process has a metal ion concentration typically less than 2500 ppm and preferably less than 1500 ppm.

[0066] 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 mav also be added as sulfuric acid during theacidulation step (4). The acidified solution typically includes a phosphate ion, that may be present in the fermentation broth.

[0067] 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.

[0068] 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.

[0069] 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-ty pe evaporator (as described below). Preferably, the evaporator of step (7) is an MVR evaporator.

[0070] 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.

[0071] The temperature of the 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 distillation unit operation is typically from 10 to 50 mbar, preferably from 20 to 50 mbar, or from 20 to 40 mbar.

[0072] 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%) by weight 3HP.

[0073] 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 a cation exchange resin and preferably an anion exchange resin. The polish ion exchange unit operation is operated to breakthrough potassium ions for the cation exchange resin beds and breakthrough pyruvic acid for the anion exchange beds. Metal ions and pyruvic acid are reduced in the 3HP product stream leaving the polish ion exchange unit operation, is described herein.

[0074] 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.

[0075] Reducing the heat load on the distillation process stream and optional post distillation evaporation process stream reduces the amount of acry lic 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 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 acry lic acid per one hundred parts by weight 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 40wt% 3HP oligomers of the total 3HP Equivalents, depending on the heat history7and length of time the concentrated 3HP product stream is maintained at the very7high concentration.

[0076] Referring to FIG. 1. 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 fdm 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. The evaporation step is preferably carried out by a mechanical vapor recompression (MVR) evaporator. In an embodiment, the evaporator is a flashtype evaporator.EXAMPLES

[0077] Representative embodiments of the present disclosure will now7be described with reference to the following example that illustrates the principles and practice of the present invention.

[0078] The following analytical methods and sample preparations are used in the examples below.Analytical Method for 3HP

[0079] 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 %.

[0080] 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 300x7.8 mm columns (BioRad), used with a Security7Guard cartridge holder (Phenomenex) and Carbo H+ guard cartridges (Phenomenex).

[0081] An Isocratic mobile phase of 10 mM H2SO4 in high-purity water, containing sodium azide (0.005%), fdtered 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 ofthe Refractive index detector is 35° C. 18.0 to 18.2 megaohm ultrapure water is used.

[0082] 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.

[0083] 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 mono-saccharides) are calculated using Refractive Index (RID) peak areas. The wt % of organic acids is calculated using UV peak area.

[0084] 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 10ns. respectively. ICP is also used to measure the content of metal ions.General Procedures3HP Fermentation Broth

[0085] 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 3 -HP fermentation broth.Filtration

[0086] 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

[0087] 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

[0088] 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 (1000xg for 5 minutes).Process Ion Exchange Unit Operation

[0089] 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 and rr - — Arming a reduced cation solution. Thepermeate 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.

[0090] 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 ion solution (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.Evaporation / Concentration

[0091] 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

[0092] 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 3-HP 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.

[0093] The distilled 3HP stream contains 3HP Equivalents concentration of 500-550 g / kg. The metal ions concentration of the distillate is less than 30 ppm and preferably less than 20 ppm. The concentration of pyruvic acid is less than 5 g / kg and preferably less than 2 g / kg.Polishing Ion Exchange Unit Operation

[0094] The distilled 3HP stream goes through a polish ion exchange unit operation using a cation exchange resin bed and an anion exchange resin bed in serial arrangement. The distilled 3HP stream is passed through the cation exchange resin bed or column.

[0095] The cation exchange resin bed is a strong acid cation exchange resin Amberlite FPC88. available from DuPont. 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, magnesium, calcium, copper, and magnesium ions present after distillation. The cation exchange resin bed of the polish ion exchange unit will also reduce the amount of iron, nickel, chromium, manganese, and molybdenum 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 ppm or less, preferably less than 10 ppm, more preferably less than 5 ppm, and sometimes less than 1 ppm.

[0096] 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 residual amounts of sulfate, phosphate, and chloride ions not removed by the process ion exchange unit operation or the distillation unit operation, and the majority of pyruvic acid. The 3HP stream leaving the polish ion exchange unit operation is a 3HP product stream.

[0097] 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.

[0098] 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

[0099] 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 com).

[0100] 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 metal ions reduced 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.

[0101] Results for this Example are reported in Table 2 and Table 3 below. As there is no polishing cation exchanger resin bed operating to remove metal cations, the metal ions content will be significantly higher for a given batch of fermentation broth processed which contains metal ions contamination (for example, metal ions that come from the fermentation process, and also may leach out of stainless steel in the distillation unit and / or downstream of the distillation unit but before the polish cation ion exchange beds. For example, if metal ions are present, such as in Example 6, then at least about 20 wt% higher metal ions than achieved in Example 6, (for example at least 50 wt% higher and sometimes at least 70 wt% higher, or at least 80 wt% higher) metal ions than achieved in Example 6 using the same starting fermentation broth.Example 2

[0102] 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).

[0103] 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 metal ions reduced 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 consumntion, regeneration chemical (4% sodiumhydroxide) use, and wastewater treatment loading by >47% compared to the process in Example1. The reduction of pyruvic acid is advantageous for an economical continuous or semi-continuous dehydration of a purified 3HP solution to acrylic acid.

[0104] Results for this Example are reported in Table 2 and Table 3 below. As there is no polishing cation exchanger resin bed operating to remove metal ions, the metal ions content will be significantly higher for a given batch of fermentation broth processed which contains metal ions contamination (for example, metal ions that come from the fermentation process, and also may leach out of stainless steel in the distillation unit and / or downstream of the distillation unit but before the polish cation ion exchange beds. For example, if metal ions are present, such as in Example 6, then at least about 20 wt% higher metal ions than achieved in Example 6, (for example at least 50 wt% higher and sometimes at least 70 wt% higher, or at least 80 wt% higher) metal ions than achieved in Example 6 using the same starting fermentation broth.Example 3

[0105] 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 lactic acid (operated on breakthrough of lactic acid in permeate of greater than 2 g / kg).

[0106] 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 metal ions reduced 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 Example2.

[0107] Results for this Example are reported in Table 2 and Table 3 below. As there is no polishing cation exchanger resin bed operating to remove metal ions, the metal ions content will be significantly higher for a given batch of fermentation broth processed which contains metalions contamination (for example, metal ions that come from the fermentation process, and also may leach out of stainless steel in the distillation unit and / or downstream of the distillation unit but before the polish cationic ion exchange beds). For example, if metal ions are present, such as in Example 6, then at least about 20 wt% higher metal ions than achieved in Example 6, (for example at least 50 wt% higher and sometimes at least 70 wt% higher, or at least 80 wt% higher) metal ions than achieved in Example 6 using the same starting fermentation broth.Example 4

[0108] 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).

[0109] The acidulated 3 HP containing solution is processed through cation exchange with a strong acid cation exchange resin (Amberlite FPC88) to minimize metal ions in the solution. This metal ions reduced solution is passed through a resin bed of weak base anion resin (Amberlite FPA 3) 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 distilled 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 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.

[0110] Results for this Example are reported in Table 2, Table 3, and Table 4 below. As there is no polishing cation exchanger resin bed operating to remove metal ions, the metal ions content will be significantly higher for a given batch of fermentation broth processed which contains metal ions contamination (for example, metal ions that come from the fermentation process, and also may leach out of stainless steel in the distillation unit and / or downstream of the distillation unit but before the polish cationic ion exchange beds. For example, if metal ions arepresent, such as in Example 6, then at least about 20 wt% higher metal ions than achieved in Example 6. (for example at least 50 wt% higher and sometimes at least 70 wt% higher, or at least 80 wt% higher) metal ions than achieved in Example 6 using the same starting fermentation broth.Example 5

[0111] 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).

[0112] The acidulated 3HP containing solution is processed through cation exchange with a strong acid cation exchange resin (Amberlite FPC88) to minimize metal ions in the solution. The metal ions reduced 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.

[0113] Results for this Example are reported in Table 2, Table 3, and Table 4 below. As there is no polishing cation exchange resin bed operating to remove metal ions, the metal ions content will be significantly higher for a given batch of fermentation broth processed which contains metal ions contamination (for example, metal ions leaching out of stainless steel in the distillation unit and / or downstream of the distillation unit but before the polish cation ion exchange beds. For example, if metal ions are present, such as in Example 6, then at least about 20 wt% higher metal ions than achieved in Example 6, (for example at least 50 wt% higher and sometimes at least 70 \\1% higher, or at least 80 \\1% higher) metal ions than achieved in Example 6 using the same starting fermentation broth.Example 6 - Use of cationic bed polish ion exchanger to reduce metal ions

[0114] 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 potassium 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).

[0115] The acidulated 3HP containing solution is processed through cation exchange with a strong acid cation exchange resin (Amberlite FPC88) to minimize metal ions in the solution. This metal ions reduced solution is passed through a resin bed of weak base anion resin (Amberlite FPA 3) 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 total 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 exchanged 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.

[0116] Results for this Example are reported in Table 2. Table 3, and Table 4 below.

[0117] If the purified 3HP solution is later dehydrated to acrylic acid under acid catalyzed conditions, residual organic acids (such as pyruvic acid) and metal ions that aren’t removed from the purified 3HP solution via distillation and metal ions typically reduce the yield of (and / or interfere with) the dehydration reaction when dehydration is operated in continuous or semi- continuous mode.Table 2.Table 3.Table 4.

[0118] 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 given for 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 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 form 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 to form a distilled 3HP stream and a bottoms stream; and removing pyruvic acid and metal ions 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 comprises less than 20 mg metal ions per kilogram of 3HP Equivalents, or less than 10 mg metal ions per kilogram of 3HP Equivalents, or less than 5 mg metal ions per kilogram 3HP Equivalents, or less than 1 mg metal ions per kilogram 3HP Equivalents, and comprises 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.

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 claim, wherein the 3HP product stream comprises less than 10 mg (for example, less than 5 mg, less than 3 mg, less than 1 mg) metal ions per kilogram of 3HP equivalents.

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

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

10. The method of any preceding claim, wherein the polish ion exchange unit operation removes at least 90% of pyruvic acid from the distilled 3HP stream; and / or wherein the polish ion exchange unit operation removes at least 95% of pyruvic acid from the distilled 3HP stream.

11. The method of any preceding claim, wherein the acidified solution comprises one or more ions selected from the group consisting of Na. K, Ca, Cu, Fe, Mg, Mn, Zn, Ni, Cr, and Mo.

12. The method of any preceding claim, wherein the polish ion exchange unit operation removes at least 75% of metal ions from the distilled 3HP stream, for example at least 90% of metal ions from the distilled 3HP stream.

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.1 . 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 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 form 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 to form a distilled 3HP stream and a bottoms stream; removing metal ions (e.g., Na, K, Ca, Cu, Fe, Mg. Mn, Zn, Ni, Cr, and / or Mo) 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 cation exchange resin bed and a second cation exchange resin bed, the first cation exchange resin bed removing metal ions until the 3HP product stream reaches a desired concentration (for example 1 ppm or 5 ppm or 10 ppm or 20 ppm) metal ion concentration off the first anion exchange resin bed, then the second cation exchange resin bed begins removing metal ions and the first cation exchange resin bed is regenerated; and optionally, 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 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.

17. The method of claim 16, 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.

18. The method of claim 16 or 17, 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.

19. The method of claim 16 or 17, wherein the polish ion exchange unit comprises at least a first cation exchange resin bed, a second cation exchange resin bed, and a third cation exchange resin bed, the first cation exchange resin bed and the second cation exchange resin bed removing metal ions until the reduced ion solution reaches a desired metal ion concentration (for example, 20 ppm, 10 ppm, 5 ppm, or 1 ppm metal ions) off the first cation exchange resin bed, then the third cation exchange resin bed begins removing metal ions and the first cation exchange resin bed is regenerated.

20. The method of any of claims 1 to 19, 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; and wherein the 3HP product stream has less than 20 mg metal ions per kilogram of 3HP equivalents, or less than 10 mg metal ions per kilogram of 3HP equivalents, or less than 5 mg metal ions per kilogram of 3HP Equivalents.

21. The method of any of claims 16 to 20, 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.

22. The method of any of claims 16 to 21. wherein the 3HP product stream has less than 20 mg metal ions per kilogram of 3HP equivalents, or less than 10 mg metal ions per kilogram of 3HP equivalents (for example, less than 5 mg, less than 3 mg, less than 1 mg metal ions).

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 3HP product.

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