Apparatus for vaporizing lactic acid

Abstract

This specification relates to a lactic acid vaporization apparatus. According to the lactic acid vaporization method and apparatus of the present invention, the content of lactic acid oligomers can be reduced and the content of lactic acid single molecules can be increased within a short period of time.

Description

Technology Field

[0001] This specification relates to a lactic acid vaporization device. Background Technology

[0003] Lactic acid, also known as lactate, is an organic acid with a relatively simple structure containing both a hydroxyl group and a carboxyl group within its molecule.

[0004] Lactic acid has traditionally been naturally produced during the fermentation process of lactose or glucose, playing a role in enhancing the flavor of fermented foods. Since it is not toxic to the human body, it has been used in various fields, such as in the food industry as flavoring agents, preservatives, and pH regulators; in the beauty industry as moisturizers and skin whitening agents; and in the medical field as intravenous fluids, dialysis fluids, and calcium supplements.

[0005] Recently, lactic acid polymers, such as polylactide, are gaining increasing interest as eco-friendly alternative polymers that can replace plastics that do not naturally decompose, such as polyolefins, polystyrene, and polyesters made from petroleum, as they are biodegradable. They are also receiving high interest as precursors for acrylic acid, which is considered very important industrially.

[0006] Lactic acid can primarily be produced through microbial fermentation or chemical synthesis methods. Recently, however, methods for producing lactic acid using biomass resources as raw materials are being researched, such as starch-based biomass like corn, sugar-based biomass like sugarcane, or cellulose-based biomass obtained from woody or herbaceous plants.

[0007] The lactic acid obtained in this way is usually stored at a high concentration during storage or distribution after production. Due to the unique structural characteristics of the lactic acid molecule, which includes both hydroxyl and carboxyl groups, it often forms a dimer structure or forms an oligomer in a dehydrated condensed form with water molecules removed.

[0008] A large amount of lactic acid is lost due to such dimerization or oligomerization. Oligomerized lactic acid increases the amount of byproducts generated in chemical reactions using lactic acid and forms coking during the reaction process, which has the problem of significantly reducing the efficiency of the reaction.

[0009] Therefore, when using concentrated stored lactic acid as lactic acid itself or incorporating it into other chemical reactions, it is necessary to reduce the content of lactic acid oligomers. Since the chemical equilibrium between lactic acid and lactic acid oligomers is known to be influenced only by the concentration of lactic acid—specifically the relative ratio of lactic acid to water—and temperature, and because the rate of equilibrium shift is very slow, there is growing interest in pretreatment methods for using concentrated lactic acid, namely, methods to reduce the content of lactic acid oligomers in the feed and increase the content of lactic acid molecules. The problem to be solved

[0011] The present specification aims to provide a lactic acid vaporization device capable of reducing the content of lactic acid oligomers and increasing the content of lactic acid single molecules within a short period of time. means of solving the problem

[0013] The present specification provides a lactic acid vaporization apparatus comprising: a feed supply unit (100) for supplying a first stream (1) containing an aqueous lactic acid solution; a steam supply unit (200) for supplying a second stream (2) containing steam; a vaporization reaction unit (300) for receiving the first stream from the feed supply unit and receiving the second stream from the steam supply unit to carry out a vaporization reaction of the aqueous lactic acid solution; and a receiving unit (400) for obtaining a third stream (3) containing vaporized lactic acid molecules.

[0015] The above vaporization reaction unit (300) may include a spraying unit (310) at its lower end that sprays a first stream supplied from the feed supply unit and a second stream supplied from the steam supply unit into the vaporization reaction unit.

[0017] The above feed supply unit may include a lactic acid aqueous solution feed (110) for supplying a lactic acid aqueous solution; and a feed pretreatment unit (120) for controlling the temperature and pressure of the first stream.

[0019] At this time, the feed pretreatment unit (120) can discharge the first stream by adjusting the temperature to about 10 to about 300 ℃.

[0021] And, the steam supply unit may include a water supply unit (210) for supplying water; and a water pretreatment unit (220) for controlling the temperature and pressure of the second stream.

[0023] At this time, the water pretreatment unit (220) can discharge the second stream by controlling it to a temperature of about 200 to about 600 ℃.

[0025] And, the spraying unit may include a mixing spray nozzle that mixes and sprays the first stream and the second stream.

[0027] According to another example, the spraying unit may include a first nozzle for spraying the first stream and a second nozzle for spraying the second stream.

[0029] In the above spraying section, the ratio of the first stream spray flow rate to the second stream spray flow rate can be adjusted to be about 1:1.5 to about 1:5.

[0031] The above receiving part may be located above the above vaporization reaction part.

[0033] And, the above-mentioned obtaining unit may include a gas-liquid separator (410) that separates and discharges vaporized lactic acid molecules and liquefied aqueous solution components.

[0035] At this time, the aqueous solution component discharged from the gas-liquid separator can be recovered and reused as a lactic acid aqueous solution feed (110).

[0037] Meanwhile, the present specification provides a method for vaporizing lactic acid, comprising the steps of: mixing and spraying a first stream of a liquid phase containing an aqueous lactic acid solution and a second stream of a gas phase containing water vapor; vaporizing the aqueous lactic acid solution through heat exchange between the first stream and the second stream; and obtaining a third stream of a gas phase containing a single molecule of lactic acid.

[0039] According to one embodiment of the invention, the aqueous lactic acid solution included in the first stream may have a lactic acid concentration of about 40 to about 99 wt%, about 45 wt% or more, or about 50 wt% or more, or about 60 wt% or more, or about 70 wt% or more, or about 75 wt% or more, and may be concentrated to a high concentration of about 99 wt% or less, about 95 wt% or less, or about 90 wt% or less, or about 85 wt% or less.

[0040] And, the concentration of the polymer in the aqueous lactic acid solution included in the first stream, that is, the concentration of lactic acid oligomers of lactic acid dimer or trimer or higher, may be about 2 to about 55 wt%, or about 2 wt% or more, or about 5% or more, or about 7 wt% or more, or about 8 wt% or more, and may be about 55 wt% or less, or about 40 wt% or less, or about 20 wt% or less, so that the content of the polymer is relatively high.

[0041] According to another embodiment of the invention, the temperature of the first stream may be about 10 to about 300°C, preferably about 10°C or more, or about 50°C or more, or about 100°C or more, and may be about 300°C or less, or about 250°C or less, or about 200°C or less.

[0043] And, the temperature of the second stream may be about 200 to about 600 ℃, preferably about 250 ℃ or higher, or about 300 ℃ or higher, or about 350 ℃ or higher, or about 400 ℃ or higher, and may be about 600 ℃ or lower, or about 550 ℃ or lower, or about 530 ℃ or lower.

[0045] At this time, it may be preferable that the temperature difference between the second stream and the first stream be about 200°C or more, or about 250°C or more, and about 500°C or less, or about 450°C or less.

[0047] According to another embodiment of the invention, the first stream may be sprayed at a flow rate of 0.05 g / min to 1.5 g / min, and the lower limit may preferably be about 0.05 g / min or more, or about 0.1 g / min or more, or about 0.15 g / min or more, or about 0.18 g / min or more, and the upper limit may preferably be about 1.5 g / min or less, or about 1.0 g / min or less, or about 0.8 g / min or less.

[0049] And, the second stream may be sprayed at a flow rate of 0.1 g / min to 4.0 g / min, and the lower limit may preferably be about 0.1 g / min or more, or about 0.2 g / min or more, or about 0.3 g / min or more, and the upper limit may preferably be about 4.0 g / min or less, or about 3.0 g / min or less, or about 2.0 g / min or less.

[0051] At this time, in the above mixing spray step, it may be preferable that the first stream flow rate : second stream flow rate be about 1 : 1.5 to about 1 : 5.

[0053] In the present invention, terms such as first, second, etc. are used to describe various components, and these terms are used solely for the purpose of distinguishing one component from another component.

[0054] Furthermore, the terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the invention.

[0055] A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0056] In this specification, terms such as “comprising,” “comprising,” or “having” are used to describe features, numbers, steps, components, or combinations thereof that are implemented, and do not exclude one or more other features, numbers, steps, components, combinations thereof, or the possibility of addition.

[0057] Additionally, in this specification, where each layer or element is referred to as being formed "on" or "above" each layer or element, it means that each layer or element is formed directly on each layer or element, or that another layer or element may be additionally formed between each layer, on an object, or on a substrate.

[0058] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0060] In this specification, the term "lactic acid" refers to a compound represented by the following chemical formula, and unless otherwise noted in this specification, it is used as a concept encompassing all lactic acid isomers, naturally occurring lactic acid dimers, and lactic acid oligomers.

[0061]

[0063] The present invention will be described in detail below.

[0065] According to one aspect of the present invention, a lactic acid vaporization apparatus is provided, comprising: a feed supply unit (100) for supplying a first stream (1) containing an aqueous lactic acid solution; a steam supply unit (200) for supplying a second stream (2) containing steam; a vaporization reaction unit (300) for receiving the first stream from the feed supply unit and receiving the second stream from the steam supply unit to carry out a vaporization reaction of the aqueous lactic acid solution; and a receiving unit (400) for obtaining a third stream (3) containing vaporized lactic acid molecules.

[0066] When using the above device, a method for vaporizing lactic acid can be implemented, comprising the steps of: mixing and spraying a first stream of a liquid phase containing an aqueous lactic acid solution and a second stream of a gas phase containing water vapor; vaporizing the aqueous lactic acid solution through heat exchange between the first stream and the second stream; and obtaining a third stream of a gas phase containing a single molecule of lactic acid.

[0067] The inventors of the present invention discovered that when a highly concentrated aqueous lactic acid solution is mixed and sprayed together with steam and vaporized through direct heat exchange, the oligomer concentration of lactic acid can be efficiently reduced in a very short period of time, and thus completed the present invention.

[0069] Lactic acid is widely used in the production of acrylic acid. Since the production of acrylic acid by dehydrating lactic acid proceeds via a gas-phase reaction, it is necessary to vaporize the lactic acid into lactic acid molecules.

[0070] However, as mentioned above, lactic acid is usually stored at high concentrations during storage or distribution after production. Due to the unique structural characteristics of the lactic acid molecule, which includes both hydroxyl and carboxyl groups, it often forms a dimer structure or forms an oligomer in a dehydrated condensed form with water molecules removed.

[0071] These lactic acid oligomer molecules can carbonize during the vaporization or reaction step to form coking, which can reduce the active surface area of ​​the reaction catalyst and be included as byproducts in the final product. Furthermore, because the presence of lactic acid oligomers significantly reduces the content of lactic acid in single-molecule form that can participate in the reaction, it is necessary to convert the lactic acid oligomers into single-molecule forms within the concentrated aqueous lactic acid solution to lower the oligomer content and increase the content of lactic acid single molecules.

[0072] However, when water is simply added to a concentrated aqueous lactic acid solution containing a high content of lactic acid oligomers to dilute the concentration, it takes a very long time to lower the content of lactic acid oligomers because the equilibrium shift speed is very slow.

[0073] Generally, to shorten this time, a high-concentration aqueous lactic acid solution of about 80 wt% or more is heated and vaporized. However, since the vaporization efficiency of lactic acid is lower than that of water, water vaporizes first, and the proportion of lactic acid in the gas phase falls below about 20 wt%. In this case, as water vaporizes first, the concentration of the remaining aqueous lactic acid solution increases further. Consequently, the concentration of oligomers in the remaining aqueous lactic acid solution also increases, which presents a problem requiring an additional processing step.

[0075] Accordingly, a lactic acid vaporization apparatus according to an aspect of the present invention comprises: a feed supply unit (100) for supplying a first stream (1) containing an aqueous lactic acid solution; a steam supply unit (200) for supplying a second stream (2) containing steam; a vaporization reaction unit (300) for receiving the first stream from the feed supply unit and receiving the second stream from the steam supply unit to carry out a vaporization reaction of the aqueous lactic acid solution; and a obtaining unit (400) for obtaining a third stream (3) containing vaporized lactic acid molecules.

[0076] FIG. 1 is a schematic diagram showing a lactic acid vaporization device according to one embodiment of the present invention.

[0077] Referring to FIG. 1, one embodiment of a lactic acid vaporization device can be seen, comprising: a feed supply unit (100) that supplies a first stream (1) containing an aqueous lactic acid solution; a steam supply unit (200) that supplies a second stream (2) containing steam; a vaporization reaction unit (300) that receives the first stream from the feed supply unit and receives the second stream from the steam supply unit to carry out a vaporization reaction of the aqueous lactic acid solution; and a obtaining unit (400) that obtains a third stream (3) containing vaporized lactic acid molecules.

[0079] That is, according to one embodiment of the present invention, instead of directly heating and vaporizing a high-concentration aqueous lactic acid solution, a high-concentration aqueous lactic acid solution is sprayed in the form of a type of aerosol, and high-temperature steam is mixed and sprayed together with it to lower the concentration of lactic acid, and at the same time, the lactic acid is vaporized through rapid heat exchange between the high-concentration lactic acid sprayed in the form of an aerosol and the steam, thereby making it possible to obtain a single molecule of vaporized lactic acid.

[0080] And in the third stream above, the concentration of lactic acid may be about 30 wt% or less, or about 25 wt% or less, or about 20 wt% or less, and the lower limit may be about 0.1 wt% or more, or about 5 wt% or more, although the lower limit may not be significant depending on the process conditions.

[0081] Here, the third stream containing a single molecule of lactic acid may, more specifically, contain less than about 1 wt% of the lactic acid oligomer described above, preferably less than about 0.5 wt% or less than about 0.1 wt%, and more preferably, may not contain substantially any lactic acid oligomer.

[0082] The statement that it substantially does not contain lactic acid oligomers means that the content of lactic acid oligomers is 0 wt% within the detectable limits of the process.

[0084] According to one embodiment of the invention, the aqueous lactic acid solution included in the first stream may have a lactic acid concentration of about 40 to about 99 wt%, about 45 wt% or more, or about 50 wt% or more, or about 60 wt% or more, or about 70 wt% or more, or about 75 wt% or more, and may be concentrated to a high concentration of about 99 wt% or less, about 95 wt% or less, or about 90 wt% or less, or about 85 wt% or less.

[0085] And, the concentration of the polymer in the aqueous lactic acid solution included in the first stream, that is, the concentration of lactic acid oligomers of lactic acid dimer or trimer or higher, may be about 2 to about 55 wt%, or about 2 wt% or more, or about 5% or more, or about 7 wt% or more, or about 8 wt% or more, and may be about 55 wt% or less, or about 40 wt% or less, or about 20 wt% or less, so that the content of the polymer is relatively high.

[0087] Here, the first stream, that is, the aqueous lactic acid solution contained in the process lactic acid feed, refers to a state in which lactic acid is dissolved in water and, as described above, naturally includes lactic acid monomolecules, lactic acid dimers, and lactic acid oligomers depending on the temperature and concentration conditions, and the lactic acid concentration described herein also refers to the concentration of lactic acid-based compounds including not only lactic acid monomolecules but also lactic acid monomolecules, lactic acid dimers, and lactic acid oligomers.

[0088] More specifically, for example, when calculated by computer modeling based on known oligomerization equilibrium constant values ​​of lactic acid, the content of oligomers at different concentrations of total lactic acid compounds is as shown in Table 1 below.

[0089] However, slight calculation errors may occur depending on the actual calculation model, and actual measured values ​​may also show slight measurement errors depending on measurement conditions or measurement methods (titration or HPLC).

[0090] Total concentration of lactic acid compounds (wt%) Single molecular concentration (wt%) Dimer concentration (wt%) Concentration of trimers or higher (wt%) 5 5.0 0.019 0.001 10 9.9 0.079 0.011 15 14.8 0.187 0.013 20 19.6 0.35 0.05 25 24.3 0.575 0.125 30 29.0 0.874 0.126 35 33.6 1.26 0.14 40 38.0 1.75 0.25 45 42.3 2.35 0.35 50 46.3 3.11 0.59 55 50.2 4.03 0.77 60 53.8 5.18 1.02 65 56.9 6.58 1.52 70 59.6 8.31 2.09 75 61.5 10.4 3.1 80 62.5 13.0 4.5 85 62.2 16.2 6.6 90 60.1 19.8 10.1 95 55.4 23.6 16 100 47.6 26.6 25.8

[0091] And, the aqueous lactic acid solution supplied from the feed (first stream) may undergo a heating process.

[0092] To this end, the feed supply unit may include a lactic acid aqueous solution feed (110) for supplying a lactic acid aqueous solution; and a feed pretreatment unit (120) for controlling the temperature and pressure of the first stream.

[0093] At this time, the feed pretreatment unit (120) can discharge the first stream by adjusting it to a temperature of about 10 to about 300 ℃ and a pressure of 1 to 50 atmospheres.

[0094] More specifically, the temperature of the first stream discharged from the feed pretreatment unit may be about 10 to about 300 ℃, preferably about 10 ℃ or more, or about 15 ℃ or more, or about 50 ℃ or more, and may be about 300 ℃ or less, or about 250 ℃ or less, or about 200 ℃ or less.

[0095] If the first stream is outside the temperature range and at an excessively low temperature, there may be a problem in that the lactic acid is not sufficiently vaporized due to the low temperature of the mixture, and if it is at an excessively high temperature, there may be a problem in that the pressure becomes excessively high to maintain the temperature.

[0096] The aqueous lactic acid solution supplied from the feed is heated and then sprayed into the vaporization reactor in the form of droplets through a transfer line and nozzle. Maintaining a high temperature and pressure of the aqueous lactic acid solution is advantageous for obtaining small droplets.

[0098] And at this time, separately from the first stream, a second stream containing water vapor is also mixed and sprayed together with the first stream in the form of droplets into the vaporization reactor through a transfer line and a nozzle.

[0099] To this end, the vaporization reaction unit (310) may include a spraying unit (310) at its lower end that sprays a first stream supplied from the feed supply unit and a second stream supplied from the steam supply unit into the vaporization reaction unit.

[0100] In the above spraying section, the first stream and the second stream may be i) combined in a pre-spraying stage and mixed and sprayed into the vaporization reaction section, ii) combined into a single nozzle in a spraying stage and mixed and sprayed into the vaporization reaction section, or iii) mixed and sprayed into the vaporization reaction section through a separate nozzle.

[0101] That is, the spraying unit may include a mixing spray nozzle that mixes and sprays the first stream and the second stream.

[0102] According to another example, the spraying unit may include a first nozzle for spraying the first stream and a second nozzle for spraying the second stream.

[0103] However, to prevent the concentration of the aqueous lactic acid solution from decreasing during the transfer process, it is more preferable that the first stream and the second stream be mixed and sprayed into the vaporization reactor through separate nozzles.

[0105] The above second stream can instantaneously lower the concentration of lactic acid in the first stream containing highly concentrated lactic acid while simultaneously transferring thermal energy to the first stream to promote the vaporization of lactic acid molecules, thereby lowering the ratio of oligomers.

[0106] In this regard, the temperature of the second stream may be about 200 to about 600°C, preferably about 250°C or higher, or about 300°C or higher, or about 350°C or higher, or about 400°C or higher, and may be about 600°C or lower, or about 550°C or lower, or about 530°C or lower.

[0107] To this end, the steam supply unit may include a water supply unit (210) for supplying water; and a water pretreatment unit (220) for controlling the temperature and pressure of the second stream.

[0108] At this time, the water pretreatment unit (220) can discharge the second stream by adjusting it to the temperature described above and a pressure range of about 1 to 10 atmospheres.

[0109] At this time, it may be preferable that the temperature difference between the second stream and the first stream be about 200°C or more, or about 250°C or more, and about 500°C or less, or about 450°C or less.

[0110] If the temperature of the second stream is outside the above range and too low, a problem may arise in which the lactic acid is not sufficiently vaporized due to the low temperature of the mixture, and if the temperature of the second stream is outside the above range and too high, a problem may arise in which the pressure becomes excessively high to maintain the temperature.

[0112] According to another embodiment of the invention, the first stream may be sprayed at a flow rate of 0.05 g / min to 1.5 g / min, and the lower limit may preferably be about 0.05 g / min or more, or about 0.1 g / min or more, or about 0.15 g / min or more, or about 0.18 g / min or more, and the upper limit may preferably be about 1.5 g / min or less, or about 1.0 g / min or less, or about 0.8 g / min or less.

[0113] If the spray volume and spray speed of the first stream are outside the above range and are too low, the flow rate of the supplied lactic acid becomes too low, which may cause a problem of over-reaction in the dehydration reaction proceeding to the next step, and if they are too high, the heat required for vaporization increases, which may result in incomplete vaporization.

[0115] And, the second stream may be sprayed at a flow rate of 0.1 g / min to 4.0 g / min, and the lower limit may preferably be about 0.1 g / min or more, or about 0.2 g / min or more, or about 0.3 g / min or more, and the upper limit may preferably be about 4.0 g / min or less, or about 3.0 g / min or less, or about 2.0 g / min or less.

[0116] If the spray volume and spray speed of the second stream are outside the above range and are too low, the heat supplied for vaporization is reduced, which may result in incomplete vaporization; if they are too high, the concentration of lactic acid becomes diluted, which may cause problems in the subsequent product separation process.

[0117] At this time, in the above mixing spraying step, it may be preferable for the spraying unit to adjust the first stream flow rate : second stream flow rate to be about 1 : 1.5 to about 1 : 5.

[0118] If the flow rate ratio of the first stream is too small outside the above range, the flow rate of the supplied lactic acid is low, resulting in low efficiency and a problem of increased load during the product separation process may occur, and if the flow rate ratio of the second stream is too small, the heat supplied for vaporization is reduced, which may result in incomplete vaporization.

[0120] According to another embodiment of the invention, before the first stream and the second stream are mixed and sprayed in the form of droplets into the vaporization reactor through the transfer line and nozzle, respectively, it may be preferable to pre-saturate the interior of the vaporization reactor with water vapor.

[0121] Through this method, when the first stream is sprayed into the reactor under high temperature conditions, water can be prevented from evaporating within the droplets of the first stream sprayed instantaneously under high temperature conditions, thereby preventing the concentration of lactic acid.

[0122] And at this time, it may be desirable for the vaporization reaction unit to proceed with the reaction while maintaining a temperature condition of about 150 to about 250 ℃.

[0124] The above receiving part may be located above the above vaporization reaction part.

[0125] After the first stream and the second stream supplied to the lower part of the vaporization reaction section are mixed and sprayed, the lactic acid single molecules generated as the aqueous lactic acid solution contained in the first stream is instantaneously vaporized move to the receiving section at the upper part of the vaporization reaction section.

[0127] And, the above-mentioned obtaining unit may include a gas-liquid separator (410) that separates and discharges vaporized lactic acid molecules and liquefied aqueous solution components.

[0128] At this time, the aqueous solution component discharged from the gas-liquid separator can be recovered and reused as a lactic acid aqueous solution feed (110). Effects of the invention

[0130] According to a method and apparatus for vaporizing lactic acid in one aspect of the present invention, in an aqueous lactic acid solution concentrated to a high concentration, the content of lactic acid oligomers can be reduced and the content of lactic acid monomolecules can be increased within a short period of time. Brief explanation of the drawing

[0132] FIG. 1 is a schematic diagram showing a lactic acid vaporization device according to one embodiment of the present invention. Specific details for implementing the invention

[0133] The operation and effects of the invention will be described in more detail below through specific embodiments. However, these embodiments are merely examples of the invention and do not define the scope of the invention.

[0135] <Example>

[0136] Aqueous lactic acid solutions of the concentrations summarized in Table 2 below were prepared.

[0137] Lactic acid solution concentration (wt%) Initial oligomer ratio Temperature (°C) Pressure (atm) Example 1 80 0.24 25 1 Example 2 80 0.23 80 1 Example 3 80 0.24 80 1 Example 4 70 0.15 80 1 Example 5 60 0.1 80 1 Example 6 80 0.23 180 10 Example 7 80 0.24 180 10

[0138] The concentration of the aqueous lactic acid solution of the feed containing all of the lactic acid, namely lactic acid, lactic acid dimers, and lactic acid oligomers, was determined by taking each sample, measuring the carbon content through elemental analysis, and dividing it by the ratio of the carbon content in the lactic acid.

[0139] The ratio of lactic acid oligomers (including dimers) in an aqueous lactic acid solution was calculated by taking each sample, analyzing the content of lactic acid single molecules using HPLC, and then dividing the amount of oligomers by the total amount of lactic acid-based compounds based on the concentration of the aqueous lactic acid solution and the content of single molecules.

[0141] Separately, a lactic acid vaporization device of the type exemplified in Fig. 1 was prepared.

[0142] The feed pretreatment section and the water pretreatment section are equipped with thermometers and temperature control devices to control the temperature of the supplied feed (first stream) and water vapor (second stream), and the receiving section is equipped with a thermometer to measure the temperature of the third stream.

[0143] First, steam was introduced into the vaporization reaction chamber to saturate the interior with steam.

[0144] Subsequently, an aqueous lactic acid solution according to Examples 1 to 7 was supplied as a first stream through a feed supply unit, and steam was supplied through a steam supply unit so that it was continuously mixed and sprayed into the vaporization reaction unit through each nozzle, and a third stream containing vaporized lactic acid molecules was obtained through a receiving unit.

[0145] The spray conditions are as summarized in the following Table 3.

[0146] Lactic acid solution temperature (°C) Lactic acid solution pressure (atm) Lactic acid solution spray volume (g / min) Water vapor temperature (°C) Water vapor spray volume (g / min) Example 1 25 1 0.6 450 1.8 Example 2 80 1 0.6 450 1.8 Example 3 80 1 0.4 500 1.2 Example 4 80 1 0.4 500 1.0 Example 5 80 1 0.2 500 0.40 Example 6 180 10 0.2 450 0.60 Example 7 180 10 0.2 500 0.35

[0147] The third stream obtained was analyzed to measure and calculate the concentration of all lactic acid-based compounds in the third stream and the ratio of oligomers among them, and summarized in Table 4 below.

[0148] Third stream temperature (°C) Lactic acid concentration (wt%) Oligomer ratio Example 1 25 14 0.08 Example 2 80 16 0.10 Example 3 80 17 0.12 Example 4 80 15 0.06 Example 5 80 <1 0 Example 6 180 19 0.04 Example 7 180 9 0.03

[0149] Referring to Table 4 above, it can be clearly seen that, according to an embodiment of the present invention, lactic acid can be continuously vaporized to reduce the content of lactic acid oligomers in a very short period of time. Explanation of the symbols

[0151] 1: 1st stream; 2: 2nd stream; 3: 3rd stream; 100: Feed supply unit; 110: Lactic acid aqueous solution feed; 120: Feed pretreatment unit; 200: Steam supply unit; 210: Water supply unit; 220: Water pretreatment unit; 300: Vaporization reaction section; 310: Spray section; 400: Receiving unit; 410: Gas-liquid separator 111, 121, 211, 221: Flow controller (valve)

Claims

Claim 1 A lactic acid vaporization device comprising: a feed supply unit for supplying a first stream containing an aqueous lactic acid solution; a steam supply unit for supplying a second stream containing steam; a vaporization reaction unit for receiving the first stream from the feed supply unit and the second stream from the steam supply unit and carrying out a vaporization reaction of the aqueous lactic acid solution; and a receiving unit for obtaining a third stream containing vaporized lactic acid molecules, wherein the vaporization reaction unit comprises a spraying unit at its lower end for spraying the first stream supplied from the feed supply unit and the second stream supplied from the steam supply unit into the vaporization reaction unit, and wherein the spraying unit comprises a first nozzle for spraying the first stream and a second nozzle for spraying the second stream. Claim 2 delete Claim 3 A lactic acid vaporization device according to claim 1, wherein the feed supply unit comprises a lactic acid aqueous solution feed for supplying a lactic acid aqueous solution; and a feed pretreatment unit for controlling the temperature and pressure of the first stream. Claim 4 In paragraph 3, the feed pretreatment unit is a lactic acid vaporization device that discharges the first stream at a temperature of 10 to 300 ℃. Claim 5 A lactic acid vaporization device according to claim 1, wherein the steam supply unit comprises: a water supply unit for supplying water; and a water pretreatment unit for controlling the temperature and pressure of the second stream. Claim 6 In claim 5, the water pretreatment unit is a lactic acid vaporization device that discharges the second stream at a temperature of 200 to 600 ℃. Claim 7 delete Claim 8 delete Claim 9 A lactic acid vaporization device according to claim 1, wherein the ratio of the first stream spray flow rate to the second stream spray flow rate in the spraying section is adjusted to be 1:1.5 to 1:

5. Claim 10 A lactic acid vaporization device according to claim 1, wherein the obtaining portion is located above the vaporization reaction portion. Claim 11 A lactic acid vaporization device according to claim 1, wherein the obtaining portion comprises a gas-liquid separator that separates and discharges vaporized lactic acid molecules and liquefied aqueous solution components. Claim 12 A lactic acid vaporization device according to claim 11, wherein the aqueous solution component discharged from the gas-liquid separator is recovered as a lactic acid aqueous solution feed and reused.

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