WO2024242863A1 - Recovery of 3-hydroxypropionic acid with partial condensation - Google Patents

Abstract

Methods of forming a concentrated 3HP solution includes partially condensing a distillation first vapor stream to form a first condensate stream and a second vapor stream. The first condensate stream has a greater 3HP concentration than the distillation feed stream. The second vapor stream is primarily water. For example, the first condensate stream may have greater than 70% by weight 3HP.

Description

RECOVERY OF 3-HYDROXYPROPIONIC ACID WITH PARTIAL CONDENSATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/504,358, filed May 25, 2023. which is incorporated by reference herein in its entirety.

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 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 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. For example, it is challenging to recover 3HP in desired concentrations without dehydrating the 3HP to form acrylic acid in undesirable concentrations. 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 or bottoms streams during the distillation of 3HP. 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. Formation of acr lic acid, oligomers of acrylic acid, and oligomers of 3HP leads to reduced 3HP recovery. The present invention provides an advantageous process for recovery of concentrated 3HP.

[0006] Methods of forming a concentrated 3HP solution includes partially condensing a distillation first vapor stream to form a first condensate stream and a second vapor stream. The first condensate stream has a greater 3HP concentration than the distillation feed stream. Utilizing partial condensation (as compared to full condensation) may advantageously reduce the size or capital cost of the distillation unit and may improve the efficiency of the concentrated 3HP recovery sy stem.

[0007] 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 from about 1 to about 3 to form an aqueous solution comprising 3-hydroxypropionic acid and produce an isolatable compound comprising a calcium sulfate compound; reducing an ion concentration of the aqueous solution to produce a reduced ion aqueous solution comprising 3-hydroxypropionic acid; removing water from the reduced ion aqueous solution to form a distillation feed stream having a feed stream 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight (or 40% to 60% by weight); distilling the distillation feed stream at a first distillation temperature value and first distillation pressure value to form a first vapor stream and a first bottoms stream; and condensing partially, at a first condensing temperature value and first condensing pressure value, the first vapor stream to form a second vapor stream and a first condensate stream, wherein the first condensate stream has a greater 3-hydroxypropionic acid concentration than the distillation feed stream.

[0008] The first condensate stream has a 3HP concentration of at least 70% by weight. The first condensate stream may have a 3HP concentration of at least 80% by weight. The first condensate stream may have a 3HP concentration of or at least 85% by weight, or at least 90% by weight, or at least 95% by weight. Condensing at concentrations above 80% by weight may need a higher temperature setpoint and may present a risk for acrylic and polyacrylic formation. Utilizing partial condensation of the distillation first vapor stream may eliminate the need for further water removal or evaporation of the first condensate stream to arrive at the desired product 3HP concentration.

[0009] 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 to lower the pH from about 1 to about 3 to form an aqueous solution comprising 3-hydroxypropionic acid and produce an isolatable compound comprising calcium; reducing an ion concentration of the aqueous solution to produce a reduced ion aqueous solution comprising 3-hydroxypropionic acid; removing water from the reduced ion aqueous solution to form a distillation feed stream having a 3-hydroxypropionic acid concentration in a range from 30% to 70% by weight (or 40% to 60% by weight); distilling the distillation feed stream at a first distillation temperature value and first distillation pressure value to form a first vapor stream and a first bottoms stream; and condensing partially, at a first condensing temperature value and first condensing pressure value, the first vapor stream to form a second vapor stream and a first condensate stream, wherein the first condensate stream has a greater 3-hydroxypropionic acid concentration than the distillation feed stream.

[0010] The first condensate stream has a 3HP concentration of at least 70% by weight. The first condensate stream may have a 3HP concentration of at least 80% by weight. The first condensate stream may have a 3HP concentration of or at least 85% by weight, or at least 90% by weight, or at least 95% by weight. Condensing at concentrations above 80% by weight may need a higher temperature setpoint and may present a risk for acrylic and polyacrylic formation. Utilizing partial condensation of the distillation first vapor stream may eliminate the need for further water removal or evaporation of the first condensate stream to arrive at the desired product 3HP concentration.

[0011] In some aspects, the method further includes removing water from the first condensate stream to form a concentrated stream comprising of 3-hydroxypropionic acid. The concentrated stream has a greater concentration of 3-hydroxypropionic acid than the first condensate stream. The concentrated stream preferably includes at least 80% by weight 3HP Equivalents, or at least 85% by weight 3HP Equivalents, or at least 90% by weight 3HP Equivalents, or at least 95% by weight 3HP Equivalents, or at least 98% by weight 3HP Equivalents.

[0012] “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 anions 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 anions of 3-hydroxypropionic acid present (but excluding the metal cations). For example, homo-oligomers 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-oligomers.

[0013] 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

[0014] 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:

[0015] FIG. 1 is a process flow diagram of the present disclosure.

[0016] FIG. 2 is a process flow diagram illustrating the distillation process steps and post distillation evaporation of Examples 1 to 7.

DETAILED DESCRIPTION

[0017] 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.

[0018] All pressure measurements are reported as absolute pressures.

[0019] 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 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.

[0020] 3HP solutions are sensitive to heat, as heat and time will promote the formation of acrylic acid, acrylic acid oligomers, 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, 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. Reducing the heat history' of 3HP solutions, specifically prior to distillation, is helpful in improving overall recovery of 3HP Equivalents utilizing the process described herein.

[0021] 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) is preferably 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, acry lic acid oligomers, or homooligomers 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 homo-oligomers of 3HR The distillation feed stream (and stored distillation feed stream) has a heat history' of no greater than 70 degrees Celsius for no greater than 60 minutes.

[0022] Recovery of concentrated 3HP poses additional challenges. Processing streams having higher 3HP concentrations may lead to greater formation of 3HP byproducts or 3HP bottoms product of distillation streams. For example, processing streams having a 3HP concentration greater than 50% or greater than 60% by weight may lead to the formation of undesirable amounts of acrylic acid, acrylic acid oligomers, or homo-oligomers of 3HP. Formation of undesirable amounts of acrylic acid, acrylic acid oligomers, or homo-oligomers of 3HP leads to reduced 3HP recoven-. The present disclosure provides an advantageous process for recovery of concentrated 3HP.

[0023] Methods of forming a concentrated 3HP solution include partially condensing a distillation first vapor stream to form a first condensate stream and a second vapor stream. The first condensate stream has a greater 3HP concentration than the distillation feed stream. The first condensate stream has a 3HP concentration of at least 70% by weight. The first condensate stream may have a 3HP concentration of at least 80% by weight, or at least 85% by weight, or at least 90% by weight, or at least 95% by weight. Utilizing partial condensation of the distillation first vapor stream may eliminate the need for further water removal or evaporation of the first condensate stream to arrive at the desired product 3HP concentration.

[0024] Water may optionally be removed from the first condensate stream to form a concentrated stream of 3HP. The concentrated stream of 3HP has a greater 3HP Equivalents concentration than the first condensate stream. The concentrated stream of 3HP may have a 3HP Equivalents concentration of at least 80% by weight. The concentrated stream of 3HP may have a 3HP Equivalents concentration of at least 85% by weight, or at least 90% by weight, or at least 95% by weight, or at least 98% by weight, or at least 99% by weight.

[0025] 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 counterions, for example calcium 3-hydroxypropionate, which is present at a higher pH.

[0026] 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.

[0027] 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 at step (5); an 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) and an optional post distillation evaporation step (9), as further described below and in the Examples.

[0028] 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 compound comprising calcium, preferably a calcium sulfate compound; 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.

[0029] 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 as a given throughput or capacity.

[0030] 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 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 45 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.

[0031] 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, or less than three parts by weight acry lic acid per one hundred parts by w eight 3HP, or less than one part by weight acry lic acid per one hundred parts by weight 3HP.

[0032] Another impurity that may be formed in the distillation feed stream is homooligomers of 3-hydroxypropionic acid. Reducing the heat load on the distillation feed stream may inhibit or reduce the amount of homo-oligomers of 3HP in the distillation feed stream. The distillation feed stream may have less than five parts by weight homo-oligomers of 3HP per one hundred parts by weight 3HP, or less than three parts by weight homo-oligomers of 3HP per one hundred parts by weight 3HP, or less than one part by weight homo-oligomers of 3HP per one hundred parts by⁷ weight 3HP. 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 low er recovery of 3HP Equivalents.

[0033] 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). Low er pH levels of the fermentation broth are advantageous for certain fermentation organisms that can ferment at commercially acceptable rates at low pH.

[0034] 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.

[0035] 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 amounts 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 may⁷ be removed after the acidification step (4), together with the removal of insoluble and/or easily isolatable compounds that may be formed during the acidification step. Cell separation may be accomplished by microfiltration or centrifuging the fermentation broth.

[0036] 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.

[0037] 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 70° 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. [0038] 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 of 3HP Equivalents is made up of at least 95% by weight 3HP, at least 98% by weight 3HP, at least 99% by weight 3HP.

[0039] 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 earn 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 compounds. 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 compounds with calcium. Addition of H2SO4 is preferred because the resulting isolatable compound is 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 compounds 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.

[0040] Referring to FIG. 1 step (6) of the present process, ion concentration of the aqueous solution is reduced. Both cations and anions are removed from the aqueous solution. The aqueous 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 aqueous solution typically includes a phosphate ion, that may be present in the fermentation broth.

[0041] This ion exchange step (6) captures ions (cations and anions) from the aqueous solution to form a reduced ion aqueous solution. The ion concentration (such as one or more of calcium, sulfate and phosphate, for example) of the reduced ion aqueous 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 aqueous 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. Reduction of the ion content in the aqueous solution prior to distillation is advantageous, because it has been found to reduce fouling in the distillation equipment. In particular, reduction of the ion content of the aqueous solution prior to distillation beneficially reduces the amount of acrylic acid formed in subsequent steps of the 3HP recoveryprocess, and also reduces the boiling point of the reduced ion aqueous solution, and reduces the energy needed to recover the 3HR

[0042] Referring to FIG. 1 step (6) of the present process, reducing the ion concentration of the aqueous solution is carried out by utilizing an ion exchanger. Preferably the ion exchanger includes an anion exchange resin and a cation exchange resin. 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 cation and anion exchange resins is about 0. 1 to 0.25 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 1.8 to 2.4.

[0043] Referring to FIG. 1 step (7) of the present invention, the evaporator may be any evaporator unit operation 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 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). In another aspect, the evaporator of step (7) is a steam evaporator. In another aspect, the evaporator of step (7) is a combination of a steam evaporator and a mechanical vapor recompression (MVR) evaporator. One exemplary evaporator includes a mechanical vapor recompression (MVR) evaporator concentrating the 3 HP containing solution to about 60% by weight 3HP and then using a steam evaporator to precisely concentrate the 60% by weight 3HP containing solution to the final 3HP concentration (such as 68% by weight 3HP, for example).

[0044] Referring to FIG. 1 step (8) of the present process, 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.

[0045] The 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. These distillation unit operation temperatures are steam jacket temperatures and not distillate temperatures.

[0046] If utilized, the temperature of the second distillation unit operation is typically from 140 °C to 200 °C, preferably from 160 °C to 190 °C, and more preferably from 170 °C to 190 °C. If utilized, the pressure of the second distillation unit operation is typically from 1 to 30 mbar, preferably from 1 to 15 mbar, and more preferably from 1 to 5 mbar. These distillation unit operation temperatures are steam jacket temperatures and not distillate temperatures.

[0047] The distillation step (8) (whether or not a second distillation unit is utilized) results in a bottoms product of distillation stream, a water stream, and a 3HP product stream having at least 70% by weight 3HP. The 3HP product stream may have a 3HP concentration of at least 80% by weight, or at least 85% by weight, or at least 90% by weight, or at least 95% by weight, or at least 98% by weight, or at least 99% by weight. The 3HP immediately after step (8) typically comprises at least 95 wt%, preferably at least 99 wt% 3-hydroxypropionic acid monomer of the total 3HP Equivalents present.

[0048] Referring to FIG. 1 step (9) and FIG. 2, the 3HP from the distillation condenser 1 (stream 134) (and optionally the 3HP from the condenser 2 (stream 151)) are optionally further evaporated using an evaporator to increase the concentration of the 3HP Equivalents and produce concentrated stream of 3HP 141. The formation of the concentrated stream of 3HP 141 is further described below. The concentrated stream of 3HP 141 ty pically has at least 80% by weight 3HP Equivalents. The concentrated 3HP product stream may have a 3HP Equivalents concentration of at least 85% by weight, or at least 90% by weight, or at least 95% by weight, or at least 98% by weight, or at least 99% by weight.

[0049] 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 3EIP product stream. The 3HP product stream may have less than five parts by weight acrylic acid per one hundred parts by weight 3HP, or less than three parts by weight acrylic acid per one hundred parts by⁷ weight 3I4P, or less than one part by weight acrylic acid per one hundred parts by weight 3HP.

[0050] Reducing the heat load on the optional post distillation evaporation process stream inhibits or reduces the amount of homo-oligomers of 3HP in the concentrated 3HP product stream. However, due to the heat history during step (8) and (9), the concentrated 3HP product stream 141 typically will have at least 1 wt%, at least 5 vrt%, 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.

[0051] Referring to FIG. 1, the distillation step (8) and optional evaporation step (9) 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, boiling tube evaporator, or combinations, thereof. The evaporation step (9) may be carried out by a mechanical vapor recompression (MVR) evaporator, a steam evaporator, or a combination of both. In an embodiment, the evaporator is a flash-type evaporator.

[0052] The distillation step (8) and optional evaporation step (9) are illustrated in FIG. 2. Distillation step (8) includes distilling the distillation feed stream 101 at a first distillation temperature value and first distillation pressure value to form a first vapor stream 112 and a first bottoms stream 114, and only partially condensing, at a first condensing temperature value and first condensing pressure value, the first vapor stream 112 to form a first condensate stream 134 and a second vapor stream 132. The first condensate stream 134 has a greater 3HP concentration than the distillation feed stream 101. This increased 3HP concentration is further described below. [0053] The first condensate stream 134 has a 3HP concentration of at least 70% by weight. The first condensate stream 134 may have a 3HP concentration of at least 80% by weight, or at least 85% by weight, or at least 90% by weight, or at least 95% by weight. The 3HP concentration of the first condensate stream 134 is a function of the amount of partial condensation provided by the first condenser 130.

[0054] The first condenser unit 130 may have two or more stages that operate at different temperatures to improve the operation of the first condenser unit 130. The first condenser unit 130 may have a first stage operating at a first temperature and a second stage operating at a second temperature, where the second temperature is less than the first temperature. The first stage may condense a majority⁷ (50% or greater, or 75% or greater, or 90% or greater) of the 3HP and leave the remaining minority of 3HP to be condensed by the second stage. For example, the first stage may operate at a temperature of around 42 to 52 degrees Celsius and the second stage may operate at a temperature of around 26 to 39 degrees Celsius. Providing a first condenser unit 130 may have two or more stages provides advantages of improved process control and process efficiency.

[0055] Water 142 may be removed from the first condensate stream 134 to form a concentrated stream of 3HP 141. The concentrated stream of 3HP 141 has a greater 3HP Equivalents concentration than the first condensate stream 134. The concentrated stream of 3HP 141 may have a 3HP Equivalents concentration of at least 80% by weight. The concentrated stream of 3HP 141 may have a 3HP Equivalents concentration of at least 85% by weight, or at least 90% by weight, or at least 95% by weight, or at least 98% by weight, or at least 99% by weight.

[0056] The illustrated distillation step (8) utilizes two distillation unit operations, a first distillation unit 110 and a second distillation unit 120. The second distillation unit 120 is fed by the first bottoms stream 114 of the first distillation unit 110. A first condenser unit 130 is fluidly coupled to the first distillation unit 110 and partially condenses the first vapor stream 112 off the first distillation unit 110 to form a first condensate stream 134 and a second vapor stream 132. A second condenser unit 150 is fluidly coupled to the second distillation unit 120 and condenses the third vapor stream 122 off the second distillation unit 120.

[0057] Utilizing two separate condenser units 130, 150 advantageously allows each condenser unit to operate at a different pressure, a different temperature, or both. Operating each condenser unit 130, 150 at different pressures and/or temperatures provides additional degrees of freedom to improve the recovery of 3I4P. [0058] Utilizing two separate distillation units 110, 120 advantageously allows each distillation unit to operate at a different pressure, a different temperature, or both. Operating each distillation unit 110, 120 at different pressures and/or temperatures provides additional degrees of freedom to improve the recovery of 3HP. In an embodiment, the second distillation unit 120 operates at a pressure value that is less than the operating pressure value of the first distillation unit 110.

[0059] The second condensing pressure value may be less than the first condensing pressure value and the second distilling pressure value is less than the first distilling pressure value. The second condensing pressure value may be less than 50% of the first condensing pressure value and the second distilling pressure value may be less than 50% of the first distilling pressure value. In an embodiment, the first condensing pressure is in a range from 20 to 50 mbar and the first condensing temperature is from 20 to 50 degrees Celsius.

[0060] The first distillation unit 110 and the first condenser unit 130 may operate at the same pressure value. The first distillation unit 110 pressure value may be within 2% of the first condenser unit 130 pressure value. The first distillation unit 110 pressure value may be within 5% of the first condenser unit 130 pressure value. The pressure drops from the first distillation unit 110 and the first condenser unit 130 may be as small as possible for maximal recovery.

[0061] The second distillation unit 120 and the second condenser unit 150 may operate at the same pressure value. The second distillation unit 120 pressure value may be within 2% of the second condenser unit 150 pressure value. The second distillation unit 120 pressure value may be within 5% of the second condenser unit 150 pressure value.

[0062] The first distillation unit 110 may separate the majority of the 3HP and nearly all of the water off as the first vapor stream 112. The remaining distillation feed stream leaves the first distillation unit 110 as a bottoms stream 114. This bottoms stream 114 may optionally be further processed in a second distillation unit 120.

[0063] The method may include the second distillation unit 120 distilling the first bottoms stream 114 at a second distillation temperature value and second distillation pressure value to form a third vapor stream 122 and a second bottoms stream 124. The second distillation pressure value being less than the first distillation pressure value. Then condensing, at a second condensing temperature value and second condensing pressure value, the third vapor stream 122 to a form a second condensate stream 151.

[0064] The second condensate stream 151 may include at least 80% by weight 3HP, or least 85% by weight 3HP, or least 90% by weight 3HP The second condensate stream 151 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 acrylic acid per one hundred parts by weight 3HP Equivalents.

[0065] In various embodiments, the second condensate stream 151 is recycled into or combined with the first condensate stream 134 (or stream 141). The second condensate stream 151 also, or alternatively can be recycled into or combined with the distillation feed stream 101.

[0066] The first condensate stream 134 has a 3I4P concentration value that is greater than the 3HP concentration value of the distillation feed stream 101. The first condensate stream 134 3HP concentration value may be 5% or 10% or 15% or 20% by weight, and in some instances greater than 30% by weight, greater than 3HP concentration value of the distillation feed stream 101. The first condensate stream 134 has a 3HP concentration of at least 70% by w eight.

[0067] The first condensate stream 134 may have a 3HP concentration of at least 70% by weight, or at least 75% by weight, or at least 85% by weight, or at least 90% by weight, or at least 95% by weight. The first condensate stream 134 may have less than five parts by weight acrylic acid per one hundred parts by weight 3I4P, or less than three parts by weight acrylic acid per one hundred parts by weight 3HP, or less than one part by weight acrylic acid per one hundred parts by weight 3HP.

[0068] The second vapor stream 132 is at least 90% by weight water, or at least 95% byweight water, or at least 98% by w eight water, or at least 99% by w eight water.

[0069] The first condensate stream 134 may be optionally further concentrated to form a concentrated stream of 3HP 141 that is formed by removing water from the first condensate stream 134. The concentrated stream has a greater concentration of 3HP than the first condensate stream 134. This further water removal step may be accomplished with an evaporator 140. The evaporator vaporizes water forming a w ater vapor stream 142. The water vapor stream 142 includes at least 95% by w eight w ater, or at least 98% by w eight w ater, or at least 99% by w eight water.

[0070] The evaporator 140 may be any evaporator that minimizes heat load or heat history to the first condensate stream 134 when forming the concentrated stream of 3HP 141. The evaporator 140 may operate at a temperature of 80 degrees Celsius or less, or in a range from 60 to 90 Celsius. The first condensate stream 134 has a limited residence time in the evaporator 140 unit operation to minimize the heat history on the process stream. For example, the first condensate stream 134 has a limited residence time in the evaporator 140 unit operation of less than 4 hours, or less than 2 hours, or less than 1 hour, preferably less than 30 minutes, or less than 15 minutes at a temperature from 60 to 90 degrees Celsius. In an embodiment the evaporator 140 is a mechanical vapor recompression (MVR) evaporator. In an embodiment, the evaporator 140 is a flash-type evaporator.

[0071] A mechanical vapor recompression evaporator utilizes vapor compression to remove water from a liquid material and therefore concentrate the amount of 3HP (and salts thereof) that are contained in a liquid. If thermal heat such as steam is readily available, evaporators that use thermal heat (with or without vacuum) can also be used. An example of an evaporator that uses thermal heat from a source such as steam to concentrate the 3HP Equivalents in a broth are shell-in-tube evaporators (such as forced recirculation and falling film evaporators). Also, evaporators that utilize both mechanical vapor recompression and thermal heat cycle(s) from sources such as steam, or heated fluid (such as oil) may be effectively utilized.

[0072] A flash-type evaporator utilizes evaporation that occurs when a saturated liquid stream undergoes a reduction in pressure by passing through a throttling valve or other throttling device. If the throttling valve or device is located at the entry into a pressure vessel so that the flash evaporation occurs within the vessel, then the vessel is often referred to as a flash drum.

[0073] A polymerization inhibitor may be added to the first condensate stream 134 to minimize the formation of polymerization products of acrylic acid. Typically, the inhibitor minimizes the polymerization of free radicals that can form with or from acry lic acid that may be formed during this last evaporation step. It also can help minimize oligomerization of acrylic acid during further processing (and/or storage) of 3HP prior to conversion of 3HP to acrylic acid. Examples of the polymerization inhibitors may include monomethyl ether hydroquinone (MEHQ). The polymerization inhibitor also may include phenothiazine (PTZ).

EXAMPLES

[0074] 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.

[0075] The following analytical methods and sample preparations are used in the examples below.

Analytical Method for 3HP

[0076] 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 %. [0077] The HPLC is a Waters Alliance 2695 modular High Performance Liquid Chromatography system that includes a pump, auto-sampler, solvent in-line gasser, 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).

[0078] 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+ megaohm ultrapure water is used.

[0079] 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.

[0080] 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 and sugars are calculated using Refractive Index (RID) peak areas. The wt % of organic acids is calculated using UV peak area.

[0081] The phosphate and sulfate ions are determined by measuring elemental sulfur and phosphorous by inductively coupled plasma atomic emission spectroscopy (ICP) analysis. Analysis is carried out using a Spectro Arcos FHS 12 instrument. All sulfur and phosphorous is assumed to be in the form of sulfate and phosphate ions, respectively. General Procedures

3HP Fermentation Broth

[0082] 3HP broth produced by fermentation from glucose in 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 maj or components of the aqueous 3HP fermentation broth.

Filtration

[0083] 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

[0084] 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

[0085] The calcium in the broth is removed by adding concentrated H2SO4 until the pH of the broth solution is between 2-2.5 forming an acidulated fermentation broth. The precipitated gypsum is removed using centrifugation (1000xg for 5 minutes). Ion Exchange (Demineralization)

[0086] The acidulated aqueous solution goes through a demineralization step using cation and anion exchange. Cation exchange is done using DOWEX88 Strong Acid Cation Exchanger resin, 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 magnesium. 3HP broth is passed through the column until breakthrough conditions (cation resin capacity is exceeded) are reached indicated by a rise in pH in the effluent stream. Depending on the ionic loading. 180L of broth is passed through the column.

[0087] The effluent from the cation exchange is then passed through an anion exchange column. The anion exchange resin is Amberlite FPA53 Weak Base Anion Exchange resin 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. 3HP cation exchange effluent is passed through the column until breakthrough conditions (anion resin capacity is exceeded) are reached indicated by a drop in pH in the effluent stream. Depending on the ionic loading. 180 L of broth are passed through the column.

Evaporation/ Concentration

[0088] The reduced ion material is concentrated using a forced circulation evaporator to a 3HP concentration of 400-600 g/L. The pressure is set to 200-300 mbar and the temperature increases from 60 to 80° C.

Distillation

[0089] Distillation is carried out using a boiling tube evaporator (BTE). Material is fed from the bottom of the unit through 1.5” x 20’ tubes heated with steam on the shell side of the heat exchanger. A first external condenser is operated at a set temperature to control the amount of water condensed from the vapor stream. The temperature is set to condense >99% of 3HP in the vapor stream. A second external condenser is operated at 4 °C to condense the remaining water and residual low boiling organic substances from the vapor stream. The substances in the feed that are not volatilized in the BTE are removed from the vapor/liquid separator via a bottoms collection system. 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

[0090] A distillation feed stream is produced as described above by utilizing the general procedures.

[0091] The distillation feed stream 101 has a 3HP concentration of 55% by weight, 25% by weight water, and 20% by weight other components. The distillation feed stream 101 is fed to the first distillation unit 110 at a rate of 1000 kg/hr. This first distillation unit 110 is a boiling tube evaporator operating at a temperature from 140 to 180 degrees Celsius and 20 to 50 mbar. A first vapor stream 112 and a first bottoms stream 114 leaves the first distillation unit 110.

[0092] The first vapor stream 112 has a 3EIP concentration of 65% by weight, 34% by weight water, and 1% by weight other components. The first vapor stream 112 leaves the first distillation unit 110 at a rate of 694 kg/hr.

[0093] The first bottoms stream 114 has a 3HP concentration of 32% by weight, less than 5% by weight water, and 65% by weight other components (including oligomers and sugars, for example). The first bottoms stream 114 leaves the first distillation unit 110 at a rate of 306 kg/hr. [0094] The first vapor stream 112 enters the first condenser unit 130 and is only partially condensed, forming the first condensate stream 134 and a second vapor stream 132. The first condenser unit 130 operates at 20 to 50 degrees Celsius at a pressure of 20 to 50 mbar (equal to the pressure of the first distillation unit).

[0095] The first condensate stream 134 has a 3HP concentration of 65% to 90% by weight (depending on the amount of condensation), 10% to 34% by weight water, and less than 2% by weight other components. The first condensate stream 134 leaves the first condenser unit 130 at a rate of 501 to 670 kg/hr (depending on the amount of condensation).

[0096] The second vapor stream 132 has a 3HP concentration of less than 1% by weight, 99% or greater by weight water, and less than 1 % by weight other components. The second vapor stream 132 leaves the first condenser unit 130 typically at a rate of 25 to 193 kg/hr (depending on the amount of condensation).

[0097] The first condensate stream 134 is optionally concentrated in an evaporator unit 140 operating at a temperature of 60 to 90 degrees Celsius and a pressure of 150 to 300 mbar. Water vapor stream 142 is removed to form the concentrated stream of 3HP 141 . The concentrated stream of 3HP 141 has a 3HP Equivalents concentration of 75% to 95% by weight 25% to 5% by weight water, and less than 1% by weight other components. The concentrated stream of 3HP 141 leaves the evaporator unit 140 at a rate of 475 to 601 kg/hr. The water vapor stream 142 (99% or greater water) leaves the evaporator unit 140 at a rate of 26 to 219 kg/hr.

[0098] The second vapor stream 132 may be condensed in a third condenser unit 160 to form a water condensate stream 161. The water condensate stream 161 (99% or greater water) leaves the third condenser unit 160 at a rate 25 to 193 kg/hr (depending on the amount of condensation in the first condenser unit 130).

[0099] The first bottoms stream 114 is the feed stream for the second distillation unit 120. The second distillation unit 120 is a wiped-film evaporator and operates at a temperature from 150 to 190 degrees Celsius and a pressure from 1 to 10 mbar. A third vapor stream 122 and a second bottoms stream 124 leaves the second distillation unit 120.

[0100] The third vapor stream 122 has a 3HP concentration of 90% by weight, 5% to 10% by weight water, and less than 5% by weight other components. The third vapor stream 122 leaves the second distillation unit 120 at a rate of 66 kg/hr.

[0101] The second bottoms stream 124 has a 3HP concentration of 30% by weight, less than 5% by weight water, and 65% to 70% by weight other components (including oligomers and sugars, for example). The second bottoms stream 124 leaves the second distillation unit 120 at a rate of 240 kg/hr.

[0102] The third vapor stream 122 enters the second condenser unit 150 and is fully condensed, forming the second condensate stream 151. The second condenser unit 150 operates at 5 degrees Celsius or less at a pressure of 2 to 10 mbar (equal to the pressure of the second distillation unit). The second condensate stream 151 has a 3HP concentration of 90% by weight, 5% to 10% by weight water, and 5% or less by weight other components. The second condensate stream 151 leaves the second condenser unit 150 at a rate of 66 kg/hr.

[0103] The second condensate stream 151 may then be recycled to the distillation feed stream 101 or the first condensate stream 131 or 141.

Example 2

[0104] This example shows the recovery of 3HP going through the process of cell removal, acidulation, ion exchange and distillation. The first condenser is operated at a specific temperature to condense a defined percentage of water in the first vapor stream to select a defined 3HP concentration in the condensate. [0105] 3HP is prepared as described in the General Procedure above. For this example, a 40% 3HP solution is fed to the BTE at a rate of 0.73 kg/hr*ft² The vacuum pressure is set at 30 mbar and the steam pressure in the jacket is set to 85 psig, resulting in a BTE wall temperature of 165 °C. The first condenser is operated at a cooling temperature of 38.3 °C to achieve a first condensate that is 90 wt% 3HP. The vapor that passes through the first condenser is passed through a second condenser to condense water from the vapor stream. The second condenser is operated at a cooling temperature of 4 °C.

[0106] Table 2. Distillation conditions using Boiling Tube Evaporator. Recovery is calculated as the amount of 3-hydroxypropionic acid (monomer) collected in the distillate stream compared to the 3-hydroxypropionic acid (monomer) and fed into the BTE.

Table 2.

[0107] This example shows that use of partial condensation can increase the 3HP concentration from 40% in the feed to 90% in the distillate by operating the condenser at a temperature that condenses only a portion of the water in the vapor stream.

Example 3

[0108] This example shows the recovery of 3HP going through the process of cell removal, acidulation, ion exchange and distillation. The first condenser is operated at a specific temperature to condense a defined percentage of water in the first vapor stream to select a defined 3HP concentration in the condensate.

[0109] 3HP is prepared as described in the General Procedure. For this example, a 50% 3HP solution is fed to the BTE at a rate of 0.73 kg/hr*ft². The vacuum pressure is set at 30 mbar and the steam pressure in the jacket is set to 85 psig, resulting in a BTE wall temperature of 165 °C. The first condenser is operated at a cooling temperature of 32.2 °C to achieve a first condensate that is 80 wt% 3HP. The vapor that passes through the first condenser is passed through a second condenser to condense water from the vapor stream. The second condenser is operated at a cooling temperature of 4 °C. [01 10] Table 3. Distillation conditions using Boiling Tube Evaporator. Recovery is calculated as the amount of 3-hydroxypropionic acid (monomer) collected in the distillate stream compared to the 3-hydroxypropionic acid (monomer) fed into the BTE.

Table 3.

[0111] This example shows that use of partial condensation can increase the 3HP concentration from 50% in the feed to 80% in the distillate by operating the condenser at a temperature that condenses only a portion of the water in the vapor stream.

Example 4

[0112] This example shows the recovery of 3HP going through the process of cell removal, acidulation, ion exchange and distillation. The first condenser is operated at a specific temperature to condense a defined percentage of water in the first vapor stream to select a defined 3HP concentration in the condensate.

[0113] 3HP is prepared as described in the General Procedure. For this example, a 60% 3HP solution is fed to the BTE at a rate of 0.73 kg/hr*ft². The vacuum pressure is set at 30 mbar and the steam pressure in the jacket is set to 85 psig, resulting in a BTE wall temperature of 165 °C. The first condenser is operated at a cooling temperature of 29.5 °C to achieve a first condensate that is 70 wt% 3HP. The vapor that passes through the first condenser is passed through a second condenser to condense water from the vapor stream. The second condenser is operated at a cooling temperature of 4 °C.

[01 14] Table 4. Distillation conditions using Boiling Tube Evaporator. Recovery is calculated as the amount of 3-hydroxypropionic acid (monomer) collected in the distillate stream compared to the 3-hydroxypropionic acid (monomer) fed into the BTE. Table 4.

Example 5

[0115] This example shows the recovery of 3HP going through the process of cell removal, acidulation, ion exchange and distillation. The first condenser is operated at a specific temperature to condense a defined percentage of water in the first vapor stream to select a defined 3HP concentration in the condensate.

[01 16] 3HP is prepared as described in the General Procedure. For this example, a 45% 3HP solution is fed to the BTE at a rate of 0.73 kg/hr*ft². The vacuum pressure is set at 30 mbar and the steam pressure in the jacket is set to 85 psig, resulting in a BTE wall temperature of 165 °C. The first condenser is operated at a cooling temperature of 26.7 °C to achieve a first condensate that is 60 wt% 3HP. The vapor that passes through the first condenser is passed through a second condenser to condense water from the vapor stream. The second condenser is operated at a cooling temperature of 4 °C.

[0117] Table 5. Distillation conditions using Boiling Tube Evaporator. Recovery is calculated as the amount of 3-hydroxypropionic acid (monomer) collected in the distillate stream compared to the 3-hydroxypropionic acid (monomer) fed into the BTE.

Table 5.

[0118] This example shows that use of partial condensation can increase the 3HP concentration from 45% in the feed to 60% in the distillate by operating the condenser at a temperature that condenses only a portion of the water in the vapor stream. Example 6

[0119] This example shows additional 3HP can be recovered by distilling the bottoms residue from the first distillation in Example 1.

[0120] The bottoms residue collected from Example 1 is distilled using a wiped film evaporator (WFE) operated at 175 °C and 5 mbar. The internal condenser of the WFE is controlled at 4 °C. The bottoms residue collected from the BTE are fed into the WFE at a rate of 10 kg/hr*ft². This bottoms stream is more concentrated in residual sugars, metal ions, salts, and 3HP oligomers compared to the aqueous 3HP solution that feeds the BTE in Example 1, as a majority of the more volatile water and 3HP is removed in the BTE distillate. The WFE distillate stream contains 90 wt% 3HP. The combined 3HP recovery from the BTE and WFE is 92%.

Example 7 - Final Evaporation with MVR On Each of the Example 2-5 Final Product

[0121] This example shows how to further increase the concentration of 3HP Equivalents through the use of MVR evaporation or flash evaporation. The final product will contain larger concentrations of homo-oligomers of 3-hydroxypropionic acid than the solutions entering this last evaporation step.

[0122] 3HP is prepared as in examples 2-5. A 3HP Equivalents solution is fed into a mechanical vapor recompression evaporator. Water was removed from the 3HP solution at pressure of 200 mbar at 80 °C to obtain a 3HP Equivalents solution of increased concentration. In the examples for concentration of examples 2 and 3, 200 ppm of the polymerization inhibitor phenothiazine (PTZ) was added to prevent polymerization of acrylic acid formed in the evaporator process. The results are reported in Table 6.

Table 6.

[0123] Experiments were carried out to determine the rate of 3HP monomer loss as a function of total 3HP concentration, temperature, and time using the following procedure and analytical method.

General procedure:

[0124] 10 g solutions of aqueous 3HP containing known wt% total 3HP were weighed into 20 mL reaction tubes containing magnetic stir bars and closed with PTFE caps. The tubes were then placed in a Heidolph Carousel 12 Plus reactor and heated at specific temperatures with stirring at 325 rpm. After specific periods of time, tubes were removed and immediately placed in an ice bath to quickly cool prior to being analyzed using the method described below. The 30 min samples were run in triplicate, while the 60 min and 120 min were run in duplicate. Tests were performed with aqueous solutions of 3HP containing 50 wt% total 3HP, 60 wt% total 3HP, and 80% total 3HP at temperature values of 60 °C, 70 °C, and 90 °C.

Analysis:

[0125] Samples were diluted by a factor of 100 into aqueous 50 mM potassium phosphate buffer at pH 2.7. The diluted samples were analyzed by HPLC on an Agilent 1290 Infinity II system equipped with a diode array UV detector set to 210 nm. Separation was achieved on an Agilent Poroshell 120 EC-C18 column (3 x 300 mm with 2.7 micron particles). The gradient held a constant blend of 95% 50 mM potassium phosphate buffer at pH 2.7 with 5% acetonitrile for the first 10 minutes of the method at a flow rate of 0.2 mL/min and temperature of 25 C. The gradient was increased linearly to 70% acetonitrile (30% 50 mM potassium phosphate buffer) from 10 to 50 minutes. The column was washed at this eluant ratio for 10 minutes before returning to starting conditions and re-equilibrated for 14 minutes. Following examples demonstrate how the 3HP monomer concentration decreased with time as concentration of total 3HP and temperature were increased.

Example 8 - Impact of time and total 3HP concentration on the concentration of monomeric 3HP [0126] Monomer conversion to oligomers increased with increase in both time and total 3HP concentration at 60 C. At 60 C and 50 wt% total 3HP, 0. 1 wt% reduction in monomeric 3HP is seen after 30 minutes. After 60 minutes and 120 minutes, the concentration of monomeric 3HP reduced by 0.2 wt% and 0.5 wt% respectively. At 60 C and 80 wt% total 3HP, 0.3 wt% reduction in monomeric 3HP is seen after 30 min. The concentration reduced by 0.6 wt% after 60 minutes and by 1.4 \\1% after 120 minutes. Results are reported in Table 7.

Table 7.

Example 9 - Impact of time and temperature on the concentration of monomeric 3HP

[0127] Monomer conversion to oligomers increased with increase in both time and temperature at 60 wt% total 3HP concentration. At 60 C and 60 wt% total 3HP, the monomer concentration reduced by 0.05 wt% after 30 minutes, by 0.2 wt% after 60 minutes and by 0.6 wt% after 120 minutes. At 90 C and 60 wt% 3HP, the monomer concentration reduced by 0.6 wt% after 30 minutes, by 1.7 wt% after 60 minutes, and by 3.2 wt % after 120 minutes. Results are reported in Table 8.

Table 8.

Example 10 - Impact of temperature and total 3HP concentration on the concentration of monomeric 3HP

[0128] Monomer conversion to oligomers increased with increase in both temperature and total 3HP concentration after 120 minutes. At 60 C and 50 wt% total 3HP, 0.5 wt% conversion to oligomers is seen after 120 minutes. The conversion increased to 1.9 wl% at 90 C and 50 wt% total 3HP concentration. At 90 C and 60 wt% total 3HP, 3.2 wt% reduction w as seen in monomeric 3HP after 120 minutes. At 90 C and 80 wt% total 3HP, 8.3 wt% reduction in monomeric 3HP was measured after 120 minutes. Results are reported in Table 9.

Table 9.

[0129] 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

CLAIMS WHAT IS CLAIMED IS:

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 from about 1 to about 3 to form an aqueous solution comprising 3-hydroxypropionic acid and produce an isolatable compound comprising a calcium sulfate compound; reducing an ion concentration in the aqueous solution to produce a reduced ion aqueous solution comprising 3-hydroxypropionic acid; removing water from the reduced ion aqueous 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 first distillation temperature value and first distillation pressure value to form a first vapor stream and a first bottoms stream; and condensing partially, at a first condensing temperature value and first condensing pressure value, the first vapor stream to form a second vapor stream and a first condensate stream, wherein the first condensate stream has a greater 3- hydroxypropionic acid concentration than the distillation feed stream.

2. The method of claim 1, wherein the first condensate stream compnses at least 70% by weight 3HP, or at least 80% by weight 3HP, or at least 85% by weight 3HP, or at least 90% by weight 3HP, or at least 95% by weight 3HP.

3. The method of claim 1 or 2, wherein the first condensate stream comprises 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 acrylic acid per one hundred parts by weight 3HP Equivalents.

4. The method of any preceding claim, wherein the second vapor stream comprises at least 90% by weight water, or at least 95% by weight water, or at least 98% by weight water, or at least 99% by weight water.

5. The method of any preceding claim, wherein the first condensing temperature value is in a range from 20 to 50 degrees Celsius and the first condensing pressure value is in a range from 20 to 50 mbar.

6. The method of any preceding claim, wherein the first distillation temperature value is in a range from 140 to 180 degrees Celsius and first distillation pressure value in a range from 20 to 50 mbar.

7. The method of any preceding claim, wherein the reducing an ion concentration in the aqueous solution comprises removing one or more of sulfate ions, phosphate ions, and calcium ions.

8. The method of any preceding claim, further comprising: removing water from the first condensate stream to form a concentrated stream comprising of 3 -hydroxy propionic acid, wherein the concentrated stream has a greater concentration of 3-hydroxypropionic acid than the first condensate stream.

9. The method of claim 8, wherein the concentrated stream comprises at least 80% by weight 3HP Equivalents, or at least 85% by weight 3HP Equivalents, or at least 90% by weight 3HP Equivalents, or at least 95% by weight 3HP Equivalents, or at least 98% by weight 3HP Equivalents.

10. The method of claims 8 or 9. wherein the concentrated stream comprises 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 acrylic acid per one hundred parts by weight 3HP Equivalents.

11. The method of any of claims 8 to 10, wherein removing water from the first condensate stream comprises removing water from the first condensate stream at a temperature of 90 degrees Celsius or less.

12. The method of any of claims 8 to 11, wherein removing water from the first condensate stream comprises removing water from the first condensate stream with a mechanical vapor recompression evaporator or a flash-type evaporator.

13. The method of any of any preceding claim, wherein the first distillation pressure value is within 5% of the first condensing pressure value, or the first distillation pressure value is within 2% of the first condensing pressure value, or the first distillation pressure value and the first condensing pressure value are equal.

14. The method of any of claims 1 to 13, further comprising: distilling the first bottoms stream at a second distillation temperature value and second distillation pressure value to form a third vapor stream and a second bottoms stream, the second distillation pressure value being less than the first distillation pressure value; and condensing, at a second condensing temperature value and second condensing pressure value, the third vapor stream to a form a second condensate stream.

15. The method of claim 14, further comprising combining the second condensate stream with the first condensate stream.

16. The method of claim 14, further comprising combining the second condensate stream with the distillation feed stream.

17. The method of any of claims 14 to 16, wherein the second condensing pressure value is less than the first condensing pressure value and the second distilling pressure value is less than the first distilling pressure value.

18. The method of any of claims 14 to 17, wherein the second condensing temperature value is less than the first condensing temperature value.

19. The method of any of claims 14 to 18, wherein the second condensing pressure value is less than 50% of the first condensing pressure value and the second distilling pressure value is less than 50% of the first distilling pressure value.

20. The method of any of claims 14 to 19, wherein the second condensing temperature value is less than 5 degrees Celsius and the second condensing pressure value in a range from 1 to 10 mbar.

21. The method of any of claims 14 to 20, wherein the second condensate stream comprises at least 80% by weight 3HP, or least 85% by weight 3HP, or least 90% by weight 3HP.

22. The method of any preceding claim, wherein the ion concentration is less than 1000 ppm in the reduced ion aqueous solution, or the ion concentration is less than 500 ppm in the reduced ion aqueous solution, or the ion concentration is less than 300 ppm in the reduced ion aqueous solution.

23. The method of any preceding claim, wherein the distillation feed stream comprises a 3- hydroxypropionic acid concentration in a range from 40% to 60% by weight.

24. The method of any preceding claim, wherein the distillation feed stream comprises less than five parts by weight homo-oligomers of 3-hydroxypropionic acid per one hundred parts by weight 3-hydroxypropionic acid, or less than three parts by weight homo-oligomers of 3- hydroxypropionic acid per one hundred parts by weight 3-hydroxypropionic acid, or less than one part by weight homo-oligomers of 3-hydroxypropionic acid per one hundred parts by weight 3-hydroxypropionic acid.

25. The method of any preceding claim, further comprising adding a polymerization inhibitor to the first condensate stream.

26. The method of claim 25, wherein the polymerization inhibitor comprises monomethyl ether hydroquinone or phenothiazine.

27. The method of any preceding claim, wherein the distillation feed stream has a heat history of no greater than 70 degrees Celsius for no greater than 60 minutes.

28. 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 to lower the pH from about 1 to about 3 to form an aqueous solution comprising 3-hydroxypropionic acid and produce an isolatable compound comprising calcium; reducing an ion concentration of the aqueous solution to produce a reduced ion aqueous solution comprising 3-hydroxypropionic acid; removing water from the reduced ion aqueous 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 first distillation temperature value and first distillation pressure value to form a first vapor stream and a first bottoms stream; and condensing partially, at a first condensing temperature value and first condensing pressure value, the first vapor stream to form a second vapor stream and a first condensate stream, wherein the first condensate stream has a greater 3- hydroxypropionic acid concentration than the distillation feed stream.

29. The method of claim 28, wherein the first condensate stream comprises at least 70% byweight 3HP, or at least 80% by weight 3HP, or at least 85% by weight 3HP, or at least 90% byweight 3HP, or at least 95% by weight 3HP.

30. The method of claim 28 or 29, wherein the first condensate stream comprises 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.

31. The method of any of claims 28 to 30, wherein the second vapor stream comprises at least 90% by weight water, or at least 95% by weight water, or at least 98% by weight w ater, or at least 99% by w eight w ater.

32. The method of any of claims 28 to 31. wherein the first condensing temperature value is in a range from 20 to 50 degrees Celsius and the first condensing pressure value is in a range from 20 to 50 mbar.

33. The method of any of claims 28 to 32, wherein the first distillation temperature value is in a range from 140 to 180 degrees Celsius and first distillation pressure value in a range from 20 to 50 mbar.

34. The method of any of claims 28 to 33, wherein the reducing an ion concentration in the fermentation broth comprises removing one or more of sulfate ions, phosphate ions, and calcium ions.

35. The method of any of claims 28 to 34, further comprising: removing water from the first condensate stream to form a concentrated stream comprising of 3 -hydroxy propionic acid, wherein the concentrated stream has a greater concentration of 3-hydroxypropionic acid than the first condensate stream.

36. The method of claim 34, wherein the concentrated stream comprises at least 80% by weight 3HP, or at least 85% by weight 3HP, or at least 90% by weight 3HP, or at least 95% by weight 3HP, or at least 98% by weight 3HP.

37. The method of claims 35 or 36, wherein the concentrated stream comprises 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 acrylic acid per one hundred parts by weight 3HP Equivalents.

38. The method of any of claims 35 to 37, wherein removing water from the first condensate stream comprises removing water from the first condensate stream at a temperature of 90 degrees Celsius or less.

39. The method of any of claims 35 to 38, wherein removing water from the first condensate stream comprises removing water from the first condensate stream with a mechanical vapor recompression evaporator or a flash-type evaporator.

40. The method of any of any claims 28 to 39, wherein the first distillation pressure value is within 5% of the first condensing pressure value, or the first distillation pressure value is within 2% of the first condensing pressure value, or the first distillation pressure value and the first condensing pressure value are equal.

41. The method of any of claims 28 to 40, further comprising: distilling the first bottoms stream at a second distillation temperature value and second distillation pressure value to form a third vapor stream and a second bottoms stream, the second distillation pressure value being less than the first distillation pressure value; and condensing, at a second condensing temperature value and second condensing pressure value, the third vapor stream to a form a second condensate stream.

42. The method of claim 41, further comprising combining the second condensate stream with the first condensate stream.

43. The method of claim 41, further comprising combining the second condensate stream with the distillation feed stream.

44. The method of any of claims 41 to 43, wherein the second condensing pressure value is less than the first condensing pressure value and the second distilling pressure value is less than the first distilling pressure value.

45. The method of any of claims 41 to 44, wherein the second condensing temperature value is less than the first condensing temperature value.

46. The method of any of claims 41 to 45, wherein the second condensing pressure value is less than 50% of the first condensing pressure value and the second distilling pressure value is less than 50% of the first distilling pressure value.

47. The method of any of claims 41 to 46. wherein the second condensing temperature value is less than 5 degrees Celsius and the second condensing pressure value in a range from 1 to 10 mbar.

48. The method of any of claims 41 to 47, wherein the second condensate stream comprises at least 80% by weight 3HP, or least 85% by weight 3HP, or least 90% by weight 3HP.

49. The method of any claims 28 to 48, wherein the ion concentration is less than 1000 ppm in the reduced ion aqueous solution, or the ion concentration is less than 500 ppm in the reduced ion aqueous solution, or the ion concentration is less than 300 ppm in the reduced ion aqueous solution.

50. The method of any of claims 28 to 49, wherein the distillation feed stream comprises a 3- hydroxypropionic acid concentration in a range from 40% to 60% by weight.

51. The method of any claims 28 to 50, wherein the distillation feed stream comprises less than five parts by weight homo-oligomers of 3-hydroxypropionic acid per one hundred parts by weight 3-hydroxypropionic acid, or less than three parts by weight homo-oligomers of 3- hydroxypropionic acid per one hundred parts by weight 3-hydroxypropionic acid, or less than one part by weight homo-oligomers of 3-hydroxypropionic acid per one hundred parts by weight 3-hydroxypropionic acid.

52. The method of any of claims 27 to 51. further comprising adding a polymerization inhibitor to the first condensate stream.

53. The method of claim 52, wherein the polymerization inhibitor comprises monomethyl ether hydroquinone or phenothiazine.

54. The method of any of claims 28 to 53, wherein the condensing partially comprises partially condensing the first vapor stream in two or more stages where each of the two or more stages each operate at different temperatures to partially condense the first vapor stream.

55. The method of any of claims 28 to 54. wherein the distillation feed stream has a heat history of no greater than 70 degrees Celsius for no greater than 60 minutes.