Rising film evaporator clean-in-place method and system

Abstract

A rising film evaporator clean-in-place method includes flowing a cleaning solution into a rising film evaporator having fermentation broth residue on one or more of the tubes; removing the fermentation broth residue with the cleaning solution; and flowing the cleaning solution and fermentation broth residue out of the boiling tube evaporator. The fermentation broth residue is disposed on a titanium-w or Ti-2 surface of the tubes. The cleaning solution has a pH of 12 or greater. The temperature of the cleaning solution does not exceed 80 degrees Celsius within the rising film evaporator. A rising film evaporator clean-in-place system is also described.

Description

RISING FILM EVAPORATOR CLEAN-IN-PLACE METHOD AND SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 582,996, filed September 15, 2023, which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to rising film evaporator clean-in-place methods and systems. In particular, the disclosure relates to rising film evaporator clean-in-place methods and systems utilized in recovery of organic acid from a fermentation broth.INTRODUCTION

[0003] Hydroxypropionic acid monomers are usefill in many applications and can be prepared by several routes. One method of manufacture includes the use of fermentation, which can produce several fermentation products, depending on the fermenting organism selected and other factors.

[0004] Rising film evaporators are utilized to recover organic acids such as hydroxypropionic acid monomers from a fermentation broth. This process results in fouling of the heat transfer surfaces within the rising film evaporator (for example, the boiling tubes internal surfaces that contact the material being evaporated are subject to fouling also referred to as ‘process surfaces’). Clean-in-place methods and systems are desired that are effective in removing residue while not harming the metal surfaces of the rising film evaporator (for example, the boiling tubes internal surfaces that contact the material being evaporated and are subject to fouling also referred to as ‘process surfaces’).SUMMARY

[0005] Hydroxypropionic acid monomers (such as: 2-hydroxypropionic acid or ‘2HP’ or lactic acid; and 3-hydroxyproprionic acid or “3HP”) are desired materials useful for many industrial applications. Efficient recovery of hydroxypropionic acid monomers from fermentation broth is challenging. Separation unit operations utilizing heat to process the fermentation broth suffers from fouling of the separation unit surfaces exposed to the elevated temperature fermentation broth. Fouling reduces the heat transfer efficiency of the separation process leading to increased costs of operation.

[0006] The present disclosure provides an advantageous clean-in-place process for rising film evaporators that separate organic acids from fermentation broth. In particular, the disclosure provides an advantageous clean-in-place process for rising film evaporators that separate hydroxypropionic acid monomers from fermentation broth. The disclosure provides an advantageous clean-in-place process for rising film evaporators that separate 2 -hydroxypropionic acid or 3 -hydroxypropionic acid from fermentation broth(s) containing 2-hydroxyproprionic acid or 3 -hydroxypropionic acid.

[0007] The rising film evaporator clean-in-place method includes: flowing a cleaning solution into a rising film evaporator having fermentation broth residue on an internal surface (or process surface) of one or more of the tubes within the rising film evaporator; removing the fermentation broth residue with the cleaning solution; and flowing the cleaning solution and fermentation broth residue out of the rising film evaporator. The fermentation broth residue is disposed on a grade 2 titanium surface of the tubes. The cleaning solution has a pH of 12 or greater, and the temperature of the cleaning solution does not exceed 80 degrees Celsius within the rising film evaporator.

[0008] The cleaning solution may have a pH in a range from 12 to 13.5, or from 12.5 to 13.5, or from 12.5 to 13. The cleaning solution has a temperature range from 70 to 80 degrees Celsius, 75 to 80 degrees Celsius, or 77 to 80 degrees Celsius. The one or more of the tubes within the rising film evaporator do not exceed 80 degrees Celsius when cleaning solution is present within the one or more of the tubes within the rising film evaporator.

[0009] Heat is added to the cleaning solution only outside of the rising film evaporator to maintain the cleaning temperature of the cleaning solution. Heat may be added to the cleaning solution prior to the cleaning solution entering the rising film evaporator.

[0010] The rising film evaporator clean-in-place system includes: a rising film evaporator having tubes. Each tube having a process inlet and a process outlet and an inner surface defining a tube lumen; a cleaning solution holding tank fluidly coupled to the rising film evaporator; a pump configured to flow cleaning solution through the tube lumens; recirculation piping configured to recirculate cleaning solution back into the rising film evaporator; a heat source configured to heat the cleaning solution to a cleaning temperature in a range from 70 to 80 degrees Celsius; process flow inlet piping fluidly connected to the process inlet of each tube; and process flow outlet piping fluidly connected to the process outlet of each tube. The heat source is external from the rising film evaporator.

[0011] 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 techniquesdescribed in this disclosure will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0012] 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:

[0013] FIG. 1 is a schematic rising film evaporator clean-in-place process flow diagram of the present disclosure;

[0014] FIG. 2 is a flow diagram of a rising film evaporator clean-in-place method; and

[0015] FIG. 3 is a graph of the results outlined in Example 1 .DETAILED DESCRIPTION

[0016] 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.

[0017] All pressure measurements are reported as absolute pressures.

[0018] 2-Hydroxypropionic acid (“2HP”) is a desired material that is useful for many industrial applications. It has been discovered that efficient recovery of 2HP in high concentrations and high purity is challenging. Separating the 2 -hydroxypropionic acid from the fermentation broth in which the 2-hydroxypropionic acid is formed is difficult since residual sugar and organic matter from the fermentation broth can be carried into the distillation / recovery unit operation(s) and form a residue on heat transfer surfaces of any vapor-liquid unit operation used to concentrate the 2- hydroxypropionic acid.

[0019] 3-Hydroxypropionic acid (“3HP”) 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. Separating the 3 -hydroxypropionic acid from the fermentation broth in which the 3 -hydroxypropionic acid is formed is difficult since the residual sugar and organic matter in the fermentation broth forms a residue on heat transfer surfaces of any vapor-liquid unit operation used to concentrate the 3-hydroxypropionic acid.

[0020] Hydroxypropionic acid monomers and / or salts thereof may be generated by a fermentation process using known fermentation techniques. For purposes of the present discussion, 2HP and / or salts means that the compound 2-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 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.

[0021] During the fermentation process, various ingredients are added to the fermentation broth to establish and maintain favorable nutrition and pH conditions to support the organism carrying out the fermentation. After completion of the fermentation, the fermentation broth contains water, organic biomass, residual sugar, hydroxypropionic acid monomers and / or salts thereof.

[0022] The fermentation broth leaving the fermentation unit operation may contain from about 0.1 to 2% by weight organic biomass, about 0.01 to 1% by weight sugar, about 10 to 20% by weight hydroxypropionic acid monomers and / or salts thereof. The fermentation broth leaving the fermentation unit operation for 3HP typically has a pH in a range from 2.5 to 6, and for 2HP typically has a pH in a range from 2 to 5.

[0023] The organic biomass may include the organism forming the desired hydroxypropionic acid monomers. When 2HP is being produced, the organic biomass may include lactobacillus microorganism cells. Other examples of organisms that make lactic acid, include microorganism, such as Issatchenkia orientalis, modified to make lactic acid (for example, modified with addition of a lactate dehydrogenase gene with deletion or disruption of the pyruvate decarboxylase gene(s) and optionally deletion or disruption of glycerol-3-phosphate dehydrogenase gene(s). Examples of organisms useful to produce 3HP include the organisms described in U.S. Patent No. 11,118, 187 B2, to Jessen et al. issued September 14, 2021, entitled “Compositions And Methods For 3- Hydroxypropionic Acid Production”.

[0024] Various separation processes may be performed on the fermentation broth to remove water, organic biomass, and residual sugar prior to the fermentation broth feeding into the rising film evaporator. These separation processes may include one or more of, filtration, centrifuging, evaporation, or precipitation.

[0025] Additionally, the at least partially purified or processed fermentation broth typically is acidulated prior to being fed to the rising film evaporator. During acidulation, acid is added to thebroth to lower its pH to a level where the hydroxypropionic aid equivalents (for example, ‘2HP Equivalents’ and ‘3HP Equivalents’) present are substantially in the free acid form (e.g., at least 95 wt%, at least 98 wt% or at least 99 wt% in the free acid form (e.g., 2HP or 3HP).

[0026] “2HP Equivalents” refers to the total 3-hydroxypropionic species present in the form of2-hydroxpropionic acid, homo-oligomers of 3-hydroxypropionic acid, and anions of 2- hydroxypropionic acid present; and 2HP Equivalents concentration refers to the total concentration of 3-hydroxypropionic species present in the form of 2-hydroxpropionic acid, homo-oligomers of 2-hydroxypropionic acid, and anions of 2-hydroxypropionic acid present (but excluding the metal cations). For example, a homo-oligomer of 2-hydroxypropionic acid would contribute to the total amount of 2-hydroxypropionic acid in an amount equal to the number of repeat units of 2-hydroxypropionic acid in the homo-oligomer.

[0027] “3HP Equivalents” refers to the total 3-hydroxypropionic species present in the form of3-hydroxpropionic 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, 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 repeat units of 3-hydroxypropionic acid in the homo-oligomer.

[0028] After acidulation, the pH of a purified broth containing 2HP typically is from 1.5 to 2.5 (for example from 1.7 to 1.9). After acidulation, the pH of a purified broth containing 3HP typically is from 1.8 to 2.4 (for example from 1.9 to 2.2). This purified broth may be fed into the rising film evaporator.

[0029] Separation processes forming the purified broth may remove substantially all the organic biomass and a substantial amount of water from the fermentation broth leaving the fermentation unit operation. And, as discussed above the acidulation step causes the purified and concentrated hydroxypropionic equivalents present within the fermentation broth (i.e., 2HP Equivalents or 3HP Equivalents) to be comprised substantially of free hydroxypropionic acid (i.e., 2HP or 3HP). The resulting fermentation broth from these separations processes is fed to the rising film evaporator unit operation to further separate water and other materials from the hydroxypropionic acid monomers (such as, 2HP or 3HP).

[0030] The fermentation broth entering the rising film evaporator unit operation may contain from about 0.5 to 20% by weight sugar (typically in the form of sugar monomers, dimers, andoligomers). This fermentation broth may contain from about 3 to 15% by weight sugar. The fermentation broth may contain from about 5 to 15% by weight sugar. The sugars may include glucose, dextrose, maltose, isomaltose, maltotriose, fructose, or sugar alcohols (such as arabitol, for example). In addition to the sugars (monomers, oligomers, and sugar alcohols), some of the sugars present in the broth may be esterified with the hydroxypropionic acid monomers (or oligomers thereof) being produced.

[0031] When 3 -hydroxypropionic acid is being produced, the fermentation broth entering the rising film evaporator unit operation may contain at least 30% by weight 3-hydroxypropoinic acid monomers. The fermentation broth entering the rising film evaporator unit operation may contain from 30% to 90% by weight 3-hydroxypropoinic acid monomers. The fermentation broth entering the rising film evaporator unit operation may contain from 30% to 70% by weight 3- hydroxypropoinic acid monomers. The fermentation broth entering the rising film evaporator unit operation may contain from 40% to 60% by weight 3-hydroxypropoinic acid monomers.

[0032] When 2-hydroxypropionic acid is being produced, the fermentation broth entering the rising film evaporator unit operation may contain at least 50% by weight 2-hydroxypropionic acid. The fermentation broth entering the rising film evaporator unit operation may contain from 50% to 90% by weight 2-hydroxypropionic acid. The fermentation broth entering the rising film evaporator unit operation may contain from 60% to 80% by weight 2-hydroxypropionic acid. The fermentation broth entering the rising film evaporator unit operation may contain from 65% to 75% by weight 2-hydroxypropionic acid.

[0033] The fermentation broth (also referred to as ‘purified broth’) entering the rising film evaporator unit operation may have a pH in a range from 1 to 3. This fermentation broth entering the rising film evaporator unit operation may have a pH in a range from 1.5 to 2.5. This fermentation broth entering the rising film evaporator unit operation and containing 2HP may have a pH in a range from 1.5 to 2.5. This fermentation broth entering the rising film evaporator unit operation and containing 3HP may have a pH in a range from 1.5 to 2.5.

[0034] The relatively high concentration of hydroxypropionic acid monomers, the rising film evaporator heat transfer surfaces (or process surfaces), in contact with the fermentation broth stream, are formed of titanium. In particular, the rising film evaporator heat transfer surfaces (or process surfaces), in contact with the fermentation broth stream, are formed of grade 2 titanium or “Ti-2”. Grade 2 titanium is referred to as ‘commercially pure’ titanium and is at least 99% titanium. Grade 2 titanium is corrosion resistant.

[0035] Grade 2 titanium is susceptible to hydrogen embrittlement when exposed to high temperature and high pH. Grade 2 titanium is susceptible to hydrogen embrittlement when exposed to temperatures greater than about 77 degrees Celsius and a pH of about 12 or greater.

[0036] It has been surprisingly found that the titanium rising film evaporator tubes are able to be cleaned-in-place, to remove hydroxypropionic acid monomer residue (and sugars residue), using the methods and systems described herein. The methods and systems described herein utilize a cleaning solution having a pH in a range from 12.0 to 13.5 and a temperature in a range from 70 to 80 degrees Celsius without causing undesirable hydrogen embrittlement of the titanium rising film evaporator tubes.

[0037] FIG. 1 is a process flow diagram of the present disclosure. A rising film evaporator clean-in-place system 100 includes a rising film evaporator 110 having tubes. Each tube in the rising film evaporator 110 has a process inlet 112 and a process outlet 114 and an inner surface defining a tube lumen.

[0038] The rising film evaporator 110 vaporizes hydroxypropionic acid monomers to separate the hydroxypropionic acid monomers from the remaining fermentation broth. The vaporized hydroxypropionic acid monomers exit the rising film evaporator 110 at the process outlet 114 or overhead space and are condensed in a condenser 170. The condensed hydroxypropionic acid monomers or distillate liquid product stream 171 proceed to final product storage.

[0039] The remaining fermentation broth exits the rising film evaporator 110 also at the process outlet 114 and may be recirculated into the rising film evaporator 110 process inlet 112 or exit the rising film evaporator unit operation and proceed to further separation processing. Typically, a portion of the remaining fermentation broth is recirculated, and a portion exits the rising film evaporator unit operation and proceeds to further separation processing to maintain a steady state.

[0040] Process flow inlet piping 113 is fluidly connected to the process inlet 112 of each tube within the rising film evaporator 110. Process flow outlet piping 115 is fluidly connected to the process outlet 114 of each tube. The process flow inlet piping 113 is fluidly connected to a fermentation broth tank 105 which holds fermentation broth following a fermentation process 101. During the clean-in-place operation cleaning solution flows into the process inlet of each tube and out of the process outlet 114 of each tube.

[0041] A vapor-liquid separator element 160 may be located along the distillate flow and between the condenser 170 and the process outlet 114 of the rising film evaporator 110. The vaporliquid separator element 160 may define a tortuous vapor path to ‘knock-down’ any entrained fermentation broth liquid particles entrained in the distillate vapor flow from the rising filmevaporator 110. During operation the vapor product 161 of the rising film evaporator 110 flows into a condenser 170 and condensed into a liquid product stream 171 enriched in hydroxypropionic acid monomers.

[0042] During the clean-in-place operation cleaning solution flows into the vapor-liquid separator element 160 via clean- in-place piping 116 to clean off the surfaces defined in the vaporliquid separator element 160. The cleaning solution flows out of the vapor-liquid separator element 160 and into the recirculation piping 140.

[0043] Fermentation broth enters the tube lumens (and contacts the process surface defining the tube lumens) of the rising film evaporator 110 and travels (usually against the force of gravity) through the tube lumens from the process inlet 112 to the process outlet 114 of each tube in the rising film evaporator 110. Heat is applied to the exterior surface of each tube and the heat transfers through the tube wall to the inner surface defining the tube lumen (or process surface).

[0044] During operation of the rising film evaporator fermentation broth deposits a fermentation broth residue on the inner surface defining the tube lumen (or process surface) reducing the heat transfer through the tube wall. The fermentation broth residue must be removed on a maintenance schedule to optimize the operation of the rising film evaporator 110.

[0045] The rising film evaporator clean-in-place system 100 also includes a cleaning solution holding tank 120 fluidly coupled via piping 123 to the rising film evaporator 110 through the fermentation broth tank 105, and a pump 130 configured to flow cleaning solution through the tube lumens. A water line 121 fills the cleaning solution holding tank 120 with water. The cleaning solution is formed by adding a basic solution 125 to achieve a pH in a range from 12 to 13.5, or from 12.5 to 13.5, or from 12.5 to 13.

[0046] The rising film evaporator clean-in-place system 100 may include recirculation piping 140 configured to recirculate cleaning solution back into the rising film evaporator 110. The recirculation piping 140 transports the cleaning solution from the process outlet 114 of each tube in the rising film evaporator 110 to the process inlet 112 of each tube in the rising film evaporator 110. One or more pumps and valves (not shown) may be utilized to accomplish this recirculation.

[0047] Once the clean-in-place operation is complete, the cleaning solution may be directed out of the rising film evaporator clean-in-place system 100 via waste piping to a cleaning solution holding tank or waste drain 144. One or more water rinse cycles may be conducted to prepare the rising film evaporator for operation.

[0048] During operation of the rising film evaporator 110 the bottoms product 142 proceeds to further processing such as further distillation to separate the hydroxypropionic acid monomersfrom the remaining fermentation broth. One or more pumps and valves (not shown) may be utilized to accomplish this.

[0049] The rising film evaporator clean-in-place system 100 includes a heat source 150 configured to heat the cleaning solution to a cleaning temperature in a range from 70 to 80 degrees Celsius. The heat source 150 is thermally coupled to the cleaning solution and is external from the rising film evaporator 110. The heat source 150 may be located along cleaning solution recirculation piping 151 of the cleaning solution holding tank 120. The heat source 150 transfers to heat to the cleaning solution before the cleaning solution enters the rising film evaporator 110. The heat source 150 does not transfer heat to the cleaning solution through the plurality of tubes forming the rising film evaporator 110. One or more pumps and valves (not shown) may be utilized to accomplish this recirculation.

[0050] Applicant discovered that heating the cleaning solution to the cleaning temperature outside of the rising film evaporator 110 avoids the tubes in the rising film evaporator 110 from being any hotter than the cleaning solution cleaning temperature. Heating the cleaning solution to the cleaning temperature inside the rising film evaporator 110 may cause, at least, localized hot spots on the areas of the titanium tubes that exceed the cleaning solution cleaning temperature.

[0051] As noted herein, the fouling residue on the inner lumens or process surfaces of the plurality of tubes forming the rising film evaporator 110 reduces the heat transfer through the plurality of tubes walls. To compensate for the reduced heat transfer, a higher temperature must be applied to the exterior surface of the plurality of tubes to reach a desired process temperature with the lumens of the plurality of tubes. This increased temperature may result in localized hot spots where fouling residue is not present or less present on the inner lumens or process surfaces of the plurality of tubes forming the rising film evaporator 110. These hot spots on the areas of the titanium tubes increase the possibility of hydrogen embrittlement of the titanium, reducing the life of the titanium tubes.

[0052] FIG. 2 is a flow diagram of a rising film evaporator clean-in-place method 200. This rising film evaporator clean-in-place method 200 may be initiated to remove fouling residue formed on the rising film evaporator process surfaces. Operation process streams may be flushed out of the rising film evaporator and the rising film evaporator clean-in-place method 200 may be initiated utilizing process pumps and valves (not shown), as needed.

[0053] The method 200 includes: flowing a cleaning solution into a rising film evaporator having fermentation broth residue on one or more of the tubes at step 202; removing thefermentation broth residue with the cleaning solution at step 204; and flowing the cleaning solution and fermentation broth residue out of the rising film evaporator at step 206.

[0054] The fermentation broth residue is disposed on a grade 2 titanium surface of the tubes (the inner lumens or process surfaces). The cleaning solution has a pH of 12 or greater, and the temperature of the cleaning solution does not exceed 80 degrees Celsius within the rising film evaporator.

[0055] The method may further include heating the cleaning solution, to a cleaning temperature in a range from 70 to 80 degrees Celsius, before flowing the cleaning solution into a rising film evaporator. The heating step may heat the cleaning solution to a cleaning temperature in a range from 75 to 80 degrees Celsius. The heating step may heat the cleaning solution to a cleaning temperature in a range from 77 to 80 degrees Celsius.

[0056] Heat may not be added to the cleaning solution when the cleaning solution is within the rising film evaporator. Heat may not be added to the cleaning solution through the tubes forming the rising film evaporator. The plurality of tubes do not exceed 80 degrees Celsius when the cleaning solution is flowing through the plurality of tubes. This may reduce or prevent hot spots exceeding 80 degrees Celsius on or in the plurality of tubes.

[0057] The cleaning solution may have a pH in a range from 12 to 13.5. The cleaning solution may have a pH in a range from 12.5 to 13.5. The cleaning solution may have a pH in a range from 12.5 to 13. The cleaning solution is an aqueous solution and includes a basic component such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, or calcium hydroxide, for example. The cleaning solution may include sodium hydroxide. The cleaning solution may include 3% to 5% by weight sodium hydroxide. The cleaning solution may include 3.5% to 4.5% by weight sodium hydroxide.

[0058] The cleaning solution may be recirculated thought the rising film evaporator for any useful cleaning time. The cleaning solution may be recirculated thought the rising film evaporator for at least 15 minutes. The cleaning solution may be recirculated thought the rising film evaporator for at least 30 minutes. The cleaning solution may be recirculated thought the rising film evaporator for at least 60 minutes. The cleaning solution may be recirculated thought the rising film evaporator for less than 300 minutes. The cleaning solution may be recirculated thought the rising film evaporator for from 30 minutes to 300 minutes. The cleaning solution may be recirculated thought the rising film evaporator for from 60 minutes to 270 minutes. The cleaning solution may be recirculated thought the rising film evaporator for from 90 minutes to 240 minutes.

[0059] Flowing the cleaning solution into a rising film evaporator includes flowing the cleaning solution into a process flow inlet of a rising film evaporator. Flowing the cleaning solution out of the rising film evaporator includes flowing the cleaning solution out of a process flow outlet of a rising film evaporator. Recirculating the cleaning solution through the rising film evaporator may include pumping the cleaning solution from the process flow outlet of the rising film evaporator to the process flow inlet of the rising film evaporator via recirculation piping.

[0060] The clean-in-place method may further include flowing cleaning solution through a vapor-liquid separator element. The vapor-liquid separator element in fluid communication with the process flow outlet of the rising film evaporator and a vapor condenser. The vapor-liquid separator element is disposed between the process flow outlet and a vapor condenser.

[0061] If 2-hydroxypropionic acid is being produced, the fermentation broth residue removed by the cleaning solution includes 2-hydroxypropionic acid monomers, sugar, esters of sugar(s) and 2-hydroxypropionic acid, or organic biomass. The fermentation broth residue removed by the cleaning solution includes 2-hydroxypropionic acid monomers or oligomers. The fermentation broth residue removed by the cleaning solution includes sugar. The fermentation broth residue removed by the cleaning solution includes organic biomass. The fermentation broth residue removed by the cleaning solution may include 2-hydroxypropionic acid monomers or oligomers, and sugar. These residues are often in a burnt or caramelized form when being removed by the cleaning solution.

[0062] If 3-hydroxypropionic acid is being produced, the fermentation broth residue removed by the cleaning solution includes 3-hydroxypropionic acid monomers, sugar, esters of sugar(s) and 3-hydroxypropionic acid, or organic biomass. The fermentation broth residue removed by the cleaning solution includes 3-hydroxypropionic acid monomers or oligomers. The fermentation broth residue removed by the cleaning solution includes sugar. The fermentation broth residue removed by the cleaning solution includes organic biomass. The fermentation broth residue removed by the cleaning solution may include 3-hydroxypropionic acid monomers or oligomers, and sugar. These residues are often in a burnt or caramelized form when being removed by the cleaning solution.

[0063] Once the rising film evaporator clean-in-place method 200 is complete, the cleaning solution may be flushed out of the rising film evaporator and the process streams fed back into the rising film evaporator utilizing process pumps and valves, as needed.EXAMPLES

[0064] 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.Example 1

[0065] This example demonstrates the improvement in recovery when the rising fdm evaporator clean- in-place system of FIG. 1 is utilized. A rising film evaporator 110 was ran for 262 days without the clean-in-place system of FIG. 1. Cleaning was done using a mildly basic solution (pH 10-11 at less than 70 °C) each month and mechanical hydroblasting on days -225 and -71. As shown in FIG. 3, recovery decreased between day -200 and day 0 due to the buildup of fermentation broth residue in the rising film evaporator. Recovery is measured as the rate of distillation flow out of the rising film evaporator divided by the rate of flow into the rising film evaporator and is reported at a percentage. One data point for each day of the experiment is shown in FIG. 3

[0066] On Day 0, the clean-in-place system of FIG. 1 was implemented using a 4% sodium hydroxide cleaning solution at 75 °C, and the rising film evaporator ran for another 669 days. As shown in FIG. 3, after implementation of the clean-in-place system the recovery remains consistent and does not decrease due to fermentation residue build up. While individual days fall outside of the consistently high recovery seen with the clean-in-place system, this is likely due to regular system fluctuations in the feedstock.Clauses

[0067] The following clauses describe various aspects of the invention described herein.Clause 1. A rising film evaporator clean-in-place method comprises: flowing a cleaning solution into a rising film evaporator having a plurality of tubes with fermentation broth residue on one or more of the plurality of tubes; removing the fermentation broth residue with the cleaning solution; and flowing the cleaning solution and fermentation broth residue out of the rising film evaporator; wherein, the fermentation broth residue is disposed on a titanium grade 2 surface of the tubes, and the cleaning solution has a pH of 12 or greater, and a temperature of thecleaning solution does not exceed 80 degrees Celsius within the rising film evaporator.Clause 2. The method according to clause 1, further comprising heating the cleaning solution, to a cleaning temperature in a range from 70 to 80 degrees Celsius, before flowing the cleaning solution into a rising film evaporator.Clause 3. The method according to clause 1 or 2, wherein the plurality of tubes do not exceed 80 degrees Celsius when the cleaning solution is flowing through the plurality of tubes.Clause 4. The method of any preceding clause, wherein the cleaning solution has a pH in a range from 12 to 13.5, or from 12.5 to 13.5, or from 12.5 to 13.Clause 5. The method of any preceding clause, further comprising recirculating the cleaning solution through the rising film evaporator for at least 15 minutes, or at least 30 minutes, or at least 60 minutes, or less than 300 minutes, or from 30 minutes to 300 minutes, or from 60 minutes to 270 minutes, or from 90 minutes to 240 minutes.Clause 6. The method according to clause 5, wherein heat is added to the recirculating cleaning solution outside of the rising film evaporator.Clause 7. The method according to clause 6, wherein heat is not added to the recirculating cleaning solution inside of the rising film.Clause 8. The method of any preceding clause, wherein the cleaning solution comprises sodium hydroxide, potassium hydroxide, magnesium hydroxide, or calcium hydroxide.Clause 9. The method according to clause 8, wherein the cleaning solution comprises sodium hydroxide.Clause 10. The method according to clause 9, wherein the cleaning solution comprises 3.5% to 4.5% by weight sodium hydroxide.Clause 11. The method of any preceding clause, wherein flowing a cleaning solution into a rising film evaporator comprises flowing a cleaning solution into a process flow inlet of a rising film evaporator.Clause 12. The method according to clause 11, wherein flowing the cleaning solution out of the rising film evaporator comprises flowing a cleaning solution out of a process flow outlet of a rising film evaporator.Clause 13. The method according to clause 12, wherein recirculating the cleaning solution through the rising film evaporator comprises pumping the cleaning solution from the process flow outlet of the rising film evaporator to the process flow inlet of the rising film evaporator via recirculation piping.Clause 14. The method of any preceding clause, further comprising flowing a cleaning solution from a cleaning solution holding tank into the rising film evaporator.Clause 15. The method of any preceding clause, further comprising flowing the cleaning solution from a rising film evaporator to a cleaning solution holding tank or waste drain.Clause 16. The method of clause 12, further comprising flowing cleaning solution through a vapor-liquid separator element, the vapor-liquid separator element in fluid communication with the process flow outlet of the rising film evaporator and a vapor condenser, the vapor-liquid separator element disposed between the process flow outlet and a vapor condenser.Clause 17. The method of any preceding clause, wherein the fermentation broth residue comprises hydroxypropionic acid monomers or sugar, or hydroxypropionic acid monomers and sugar.Clause 18. The method of any preceding clause, wherein the fermentation broth residue comprises 2-hydroxyprop ionic acid or 3 -hydroxypropionic acid.Clause 19. The method of any preceding clause, wherein the fermentation broth residue comprises 2-hydroxypropionic acid.Clause 20. The method of any preceding clause, wherein the fermentation broth residue comprises 3-hydroxypropionic acid.Clause 21. A rising film evaporator clean- in-place system comprises: a rising film evaporator having tubes, each tube having a process inlet and a process outlet and an inner surface defining a tube lumen; a cleaning solution holding tank fluidly coupled to the rising film evaporator; a pump configured to flow cleaning solution through the tube lumens; recirculation piping configured to recirculate cleaning solution back into the rising film evaporator; a heat source configured to heat the cleaning solution to a cleaning temperature in a range from 70 to 80 degrees Celsius, the heat source being external from the rising film evaporator; process flow inlet piping fluidly connected to the process inlet of each tube; and process flow outlet piping fluidly connected to the process outlet of each tube.Clause 22. The rising film evaporator clean-in-place system according to clause 21 , wherein the cleaning solution flows into the process inlet of each tube.Clause 23. The rising film evaporator clean-in-place system according to clause 21 or clause 22, wherein the tube lumen is formed of grade 2 titanium.Clause 24. The rising film evaporator clean-in-place system according to any of clauses 21 to 23, wherein the process flow inlet piping is fluidly connected to a fermentation broth tank.Clause 25. The rising film evaporator clean-in-place system according to any of clauses 21 to 24, wherein the heat source is thermally coupled to the cleaning solution before the cleaning solution enters the rising film evaporator, to heat the cleaning solution to the cleaning temperature.Clause 26. The rising film evaporator clean-in-place system according to any of clauses 21 to 25, wherein the cleaning solution has a pH in a range from 12 to 13.5, or from 12.5 to 13.5, or from 12.5 to 13.Clause 27. The rising film evaporator clean-in-place system according to any of clauses 21 to 26, further comprising a vapor condenser and a vapor-liquid separator element, in fluid communication and disposed between, the rising film evaporator and a vapor condenser.Clause 28. Use of the rising film evaporator clean-in-place system according to any of clauses 21 to 27 wherein the rising film evaporator separates hydroxypropionic acid from fermentation broth.Clause 29. Use of the rising film evaporator clean-in-place system according to any of clauses 21 to 27 wherein the rising film evaporator separates 2-hydroxypropionic acid or 3- hydroxypropionic acid from fermentation broth.Clause 30. Use of the rising film evaporator clean-in-place system according to any of clauses 21 to 27 wherein the rising film evaporator separates 2-hydroxypropionic acid from fermentation broth.Clause 31. Use of the rising film evaporator clean-in-place system according to any of clauses 21 to 27 wherein the rising film evaporator separates 3 -hydroxypropionic acid from fermentation broth.

[0068] 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

CLAIMSWHAT IS CLAIMED IS:

1. A rising film evaporator clean-in-place method comprising: flowing a cleaning solution into a rising film evaporator having a plurality of tubes with fermentation broth residue on one or more of the plurality of tubes; removing the fermentation broth residue with the cleaning solution; and flowing the cleaning solution and fermentation broth residue out of the rising film evaporator; wherein, the fermentation broth residue is disposed on a titanium grade 2 surface of the tubes, and the cleaning solution has a pH of 12 or greater, and a temperature of the cleaning solution does not exceed 80 degrees Celsius within the rising film evaporator.

2. The method according to claim 1, further comprising heating the cleaning solution, to a cleaning temperature in a range from 70 to 80 degrees Celsius, before flowing the cleaning solution into a rising film evaporator.

3. The method according to claim 1 or 2. wherein the plurality of tubes do not exceed 80 degrees Celsius when the cleaning solution is flowing through the plurality of tubes.

4. The method of any preceding claim, wherein the cleaning solution has a pH in a range from 12 to 13.5, or from 12.5 to 13.5, or from 12.5 to 13.

5. The method of any preceding claim, further comprising recirculating the cleaning solution through the rising film evaporator for at least 15 minutes, or at least 30 minutes, or at least 60 minutes, or less than 300 minutes, or from 30 minutes to 300 minutes, or from 60 minutes to 270 minutes, or from 90 minutes to 240 minutes.

6. The method of any preceding claim, wherein the cleaning solution comprises sodium hydroxide, potassium hydroxide, magnesium hydroxide, or calcium hydroxide.

7. The method according to claim 6, wherein the cleaning solution comprises 3.5% to 4.5% by weight sodium hydroxide.

8. The method according to claim 5, wherein recirculating the cleaning solution through the rising film evaporator comprises pumping the cleaning solution from the process flow outlet of the rising film evaporator to the process flow inlet of the rising film evaporator via recirculation piping.

9. The method of any preceding claim, further comprising flowing a cleaning solution from a cleaning solution holding tank into the rising film evaporator.

10. The method of any preceding claim, further comprising flowing the cleaning solution from a rising film evaporator to a cleaning solution holding tank or waste drain.

11. The method of any preceding claim, further comprising flowing the cleaning solution from the rising film evaporator through a vapor-liquid separator element, the vapor-liquid separator element in fluid communication with the process flow outlet of the rising film evaporator and a vapor condenser, the vapor-liquid separator element disposed between the process flow outlet and a vapor condenser.

12. The method of any preceding claim, wherein the fermentation broth residue comprises hydroxypropionic acid monomers and sugar, or hydroxypropionic acid monomers and sugar.

13. A rising film evaporator clean-in-place system comprising: a rising film evaporator having tubes, each tube having a process inlet and a process outlet and an inner surface defining a tube lumen; a cleaning solution holding tank fluidly coupled to the rising film evaporator; a pump configured to flow cleaning solution through the tube lumens; recirculation piping configured to recirculate cleaning solution back into the rising film evaporator; a heat source configured to heat the cleaning solution to a cleaning temperature in a range from 70 to 80 degrees Celsius, the heat source being external from the rising film evaporator;process flow inlet piping fluidly connected to the process inlet of each tube; and process flow outlet piping fluidly connected to the process outlet of each tube.

14. The rising film evaporator clean-in-place system according to claim 13, wherein the cleaning solution flows into the process inlet of each tube.

15. The rising film evaporator clean-in-place system according to claim 13 or claim 14, wherein the tube lumen is formed of grade 2 titanium.

16. The rising film evaporator clean-in-place system according to any of claims 13 to 15. wherein the process flow inlet piping is fluidly connected to a fermentation broth tank.

17. The rising film evaporator clean-in-place system according to any of claims 13 to 16, wherein the heat source is thermally coupled to the cleaning solution before the cleaning solution enters the rising film evaporator, to heat the cleaning solution to the cleaning temperature.

18. The rising film evaporator clean-in-place system according to any of claims 13 to 17. wherein the cleaning solution has a pH in a range from 12 to 13.5, or from 12.5 to 13.5, or from 12.5 to 13.

19. The rising film evaporator clean-in-place system according to any of claims 13 to 18. further comprising a vapor condenser and a vapor-liquid separator element, in fluid communication and disposed between, the rising film evaporator and a vapor condenser.

20. Use of the rising film evaporator clean-in-place system according to any of claims 13 to 19 in a rising film evaporator that separates hydroxypropionic acid from fermentation broth, for example 2-hydroxypropionic acid or 3-hydroxypropionic.

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