Method For Vaporizing Lactic Acid, Apparatus For Vaporizing Lactic Acid, And Method For Preparing Acrylic Acid From Lactic Acid

Abstract

The present disclosure relates to a method and an apparatus for vaporizing lactic acid. According to the method and apparatus, the content of lactic acid oligomers can be reduced within a short period of time, and the content of single-molecule lactic acid can be increased. The method includes heating and pressurizing a lactic acid aqueous solution, spraying a 1-1 stream of a liquid phase containing the heated and pressurized lactic acid aqueous solution, vaporizing the lactic acid contained in the 1-1 stream through spraying; and obtaining a 1-3 stream of a gas phase containing single-molecule lactic acid.

Claims

1. A method for vaporizing lactic acid comprising: heating and pressurizing a lactic acid aqueous solution; spraying a 1-1 stream of a liquid phase containing the heated and pressurized lactic acid aqueous solution; vaporizing the lactic acid contained in the 1-1 stream through spraying; and obtaining a 1-3 stream of a gas phase containing lactic acid molecules.

2. The method for vaporizing lactic acid according to claim 1, wherein: in the heating and pressurizing, the lactic acid aqueous solution is heated and pressurized under conditions of a temperature of 150° C. to 250° C. and a pressure of 1 bar to 40 bar.

3. The method for vaporizing lactic acid according to claim 1, wherein: the concentration of the lactic acid aqueous solution is 20 to 99 wt. %.

4. The method for vaporizing lactic acid according to claim 1, wherein: a temperature of the 1-1 stream is 10° C. to 300° C.

5. The method for vaporizing lactic acid according to claim 1, wherein: the 1-1 stream is sprayed at a flow rate of 0.1 g/min to 1.0 g/min.

6. The method for vaporizing lactic acid according to claim 1, further comprising: when the 1-1 stream is sprayed, mixing and spraying the 1-1 stream and a 1-2 stream of a gas phase containing a steam.

7. The method for vaporizing lactic acid according to claim 6, wherein: a temperature of the 1-2 stream is 200° C. to 600° C.

8. The method for vaporizing lactic acid according to claim 6, wherein: the 1-2 stream is sprayed at a flow rate of 0.1 g/min to 3.0 g/min.

9. The method for vaporizing lactic acid according to claim 6, wherein: in the mixing and spraying, a ratio of a 1-1 stream flow rate to a 1-2 stream flow rate=1:1.5 to 1:5.

10. A method for preparing acrylic acid, comprising: obtaining lactic acid molecules by vaporizing lactic acid according to the method of claim 1; subjecting the lactic acid molecules to a dehydration reaction to prepare acrylic acid; and obtaining the acrylic acid.

11. An apparatus for vaporizing lactic acid, comprising: a pretreatment section configured to heat and pressurize a lactic acid aqueous solution; a feed supply section configured to receive a supply of the lactic acid aqueous solution from the pretreatment section and supply a 1-1 stream containing the lactic acid aqueous solution; a spray section configured to spray the 1-1 stream transferred from the feed supply section into the vaporization reactor; a vaporization reactor configured to vaporize the sprayed lactic acid aqueous solution; and an obtaining section configured to obtain a 1-3 stream containing vaporized lactic acid molecules.

12. The apparatus for vaporizing lactic acid according to claim 11, wherein: the pretreatment section further comprises a temperature adjusting part and a pressure regulating part configured to heat and pressurize the lactic acid aqueous solution under conditions of a temperature of 150° C. to 250° C. and a pressure of 1 bar to 40 bar.

13. The apparatus for vaporizing lactic acid according to claim 12, wherein: the concentration of the lactic acid aqueous solution is 20 to 99 wt. %.

14. The apparatus for vaporizing lactic acid according to claim 11, wherein: the feed supply section further comprises a feed temperature adjusting part configured to adjust a temperature of the 1-1 stream to 150 to 300° C.

15. The apparatus for vaporizing lactic acid according to claim 11, wherein: the spray section comprises a 1-1 stream nozzle configured to adjusts so that the 1-1 stream is sprayed at a flow rate of 0.1 g/min to 1.0 g/min.

16. The apparatus for vaporizing lactic acid according to claim 11, further comprising a steam supply section configured to supply steam, and the spray section further comprises a 1-2 stream nozzle configured to receive supply of steam from the steam generator and spray a 1-2 stream of a gas phase containing a steam into an interior of the vaporization reactor.

17. The apparatus for vaporizing lactic acid according to claim 16, wherein: the steam supply section further comprises a steam temperature adjusting part configured to adjust a temperature of the 1-2 stream to 200 to 600° C.

18. The apparatus for vaporizing lactic acid according to claim 16, wherein: the spray section is configured to adjust so that the 1-2 stream is sprayed at a flow rate of g/min to 3.0 g/min.

19. The apparatus for vaporizing lactic acid according to claim 16, wherein: the spray section is configured to adjust so that a ratio of a 1-1 stream flow rate to a 1-2 stream flow rate=1:1.5 to 1:5.

20. A method for vaporizing lactic acid comprising: mixing and spraying a 3-1 stream of a liquid phase containing a lactic acid aqueous solution and a 3-2 stream of a gas phase containing a steam; vaporizing the lactic acid aqueous solution through heat exchange between the 3-1 stream and the 3-2 stream; and obtaining a 3-3 stream of a gas phase containing single-molecule lactic acid.

21. The method for vaporizing lactic acid according to claim 20, wherein: the lactic acid aqueous solution contained in the 3-1 stream has a lactic acid concentration of 40 to 99 wt. %.

22. The method for vaporizing lactic acid according to claim 20, wherein: a concentration of a multimer in the lactic acid aqueous solution contained in the 3-1 stream is 2 to 55 wt. %.

23. The method for vaporizing lactic acid according to claim 20, wherein: a temperature of the 3-1 stream is 10 to 300° C.

24. The method for vaporizing lactic acid according to claim 20, wherein: a temperature of the 3-2 stream is 200 to 600° C.

25. The method for vaporizing lactic acid according to claim 20, wherein: a temperature difference between the 3-2 stream and the 3-1 stream is 200° C. to 500° C.

26. The method for vaporizing lactic acid according to claim 20, wherein: the 3-1 stream is sprayed at a flow rate of 0.05 g/min to 1.5 g/min.

27. The method for vaporizing lactic acid according to claim 20, wherein: the 3-2 stream is sprayed at a flow rate of 0.1 g/min to 4.0 g/min.

28. The method for vaporizing lactic acid according to claim 20, wherein: in the mixing and spraying, a ratio of a 3-1 stream flow rate to a 3-2 stream flow rate=1:1.5 to 1:5.

29. A method for preparing acrylic acid, comprising: obtaining lactic acid molecules by vaporizing lactic acid according to the method of claim 20; subjecting the lactic acid molecules to a dehydration reaction to prepare acrylic acid; and obtaining the acrylic acid.

30. An apparatus for vaporizing lactic acid, comprising: a feed supply section configured to supply a 3-1 stream containing a lactic acid aqueous solution; a steam supply section configured to supply a 3-2 stream containing a steam; a vaporization reaction section configured to receive a supply of a 3-1 stream from the feed supply section and receive a supply of a 3-2 stream from the steam supply section to perform a vaporization reaction of a lactic acid aqueous solution; and an obtaining section configured to obtain a 3-3 stream containing vaporized lactic acid molecules.

31. The apparatus for vaporizing lactic acid according to claim 30, wherein: the vaporization reaction section comprises a spray section configured to spray a 3-1 stream supplied from the feed supply section at a lower end and a 3-2 stream supplied from the steam supply section into an interior of the vaporization reaction section.

32. The apparatus for vaporizing lactic acid according to claim 30, wherein: the feed supply section comprises a lactic acid aqueous solution feed that supplies a lactic acid aqueous solution; and a feed pretreatment section configured to adjust temperature and pressure of the 3-1 stream.

33. The apparatus for vaporizing lactic acid according to claim 32, wherein: the feed pretreatment section is configured to discharges the 3-1 stream at a temperature of 10 to 300° C.

34. The apparatus for vaporizing lactic acid according to claim 30, wherein: the steam supply section comprises a water supply section configured to supply water, and the steam supply section further comprises a water pretreatment section configured to adjust the temperature and pressure of the 3-2 stream.

35. The apparatus for vaporizing lactic acid according to claim 34, wherein: the water pretreatment section is configured to discharge the 3-2 stream at a temperature of 200 to 600° C.

36. The apparatus for vaporizing lactic acid according to claim 31, wherein: the spray section comprises a mix spray nozzle configured to mix and spray the 3-1 stream and the 3-2 stream.

37. The apparatus for vaporizing lactic acid according to claim 31, wherein: the spray section comprises a 3-1 nozzle configured to spray the 3-1 stream, and a 3-2 nozzle configured to spray the 3-2 stream.

38. The apparatus for vaporizing lactic acid according to claim 31, wherein: the spray section is configured to adjust so that a ratio of a 3-1 stream spray flow rate to a 3-2 stream spray flow rate is 1:1.5 to 1:5.

39. The apparatus for vaporizing lactic acid according to claim 30, wherein: the obtaining section is located above the vaporization reaction section.

40. The apparatus for vaporizing lactic acid according to claim 30, wherein: the obtaining section comprises a gas-liquid separator configured to separate and discharge vaporized lactic acid molecules and liquefied aqueous solution components.

41. The method for vaporizing lactic acid according to claim 1, further comprising: separating and discharging the vaporized lactic acid molecules and liquefied aqueous solution components of the 1-3 stream; and recovering and reusing the liquefied aqueous solution components as a lactic acid aqueous solution feed.

Description

BRIEF DESCRIPTION OF DRAWING

[0186] FIG. 1s a schematic diagram showing the apparatus for vaporizing lactic acid according to an embodiment of the present disclosure.

EXAMPLES

[0187] Hereinafter, the action and effect of the invention will be described in more detail with reference to specific examples of the invention. However, these examples are presented for illustrative purposes only and the scope of the invention is not limited thereby in any way.

First Example

[0188] A lactic acid aqueous solution having a concentration of about 80 wt. % was prepared.

[0189] In the pretreatment section, the lactic acid aqueous solution was heated and pressurized under the conditions of 180° C. and 10 atm, and prepared for supplying as a feed.

TABLE-US-00003 TABLE 3 Concentration of lactic acid aqueous solution Ratio of Temperature Pressure (wt. %) oligomer (° C.) (atm) Example 80 0.23 180 10 1 Example 80 0.24 180 10 2

[0190] The concentration of lactic acid aqueous solution, that is, the lactic acid aqueous solution concentration of the feed containing all of lactic acid, lactic acid dimer and lactic acid oligomer was determined by collecting each sample, measuring the carbon content by elemental analysis, and dividing by the ratio of carbon content in lactic acid.

[0191] The ratio of lactic acid oligomer (including dimer) in the lactic acid aqueous solution was calculated by collecting each sample, analyzing the content of lactic acid single molecules through HPLC, and dividing the amount of oligomers by the amount of total lactic acid-based compounds from the concentration of the aqueous lactic acid solution and the content of single molecules.

[0192] Next, an apparatus for vaporizing lactic acid, comprising: a pretreatment section that heats and pressurizes an aqueous lactic acid solution having a 1-1 concentration; a feed supply section that receives the supply of the aqueous lactic acid solution from the pretreatment section and supplies a 1-1 stream containing the aqueous lactic acid solution; a spray section that sprays the 1-1 stream transferred from the feed supply section into the vaporization reactor; a vaporization reactor that vaporizes the sprayed aqueous lactic acid solution; and an obtaining section that obtains a 1-3 stream containing vaporized lactic acid molecules, was prepared.

[0193] A thermometer and a temperature control device were provided in the feed supply section and the steam supply section, whereby the temperature of the supplied feed (1-1 stream) and water vapor (1-2 stream) can be adjusted. The obtaining section was equipped with a thermometer to measure the temperature of the 1-3 stream.

[0194] First, steam was charged into the vaporization reactor so that the interior of the vaporization reactor was saturated with steam.

[0195] Then, the lactic acid aqueous solution according to Examples 1 to 7 was supplied to the 1-1 stream through the feed supply section, the steam was supplied through the steam supply section, and continuously mixed and sprayed into the inside of the vaporization reaction section through each nozzle. Thereby, the 1-3 stream containing vaporized lactic acid molecules was obtained through the obtaining section.

[0196] The spray conditions are as summarized in Table 4 below.

TABLE-US-00004 TABLE 4 Spray Temperature Pressure amount of of lactic of lactic lactic acid Steam acid aqueous acid aqueous aqueous temper- Amount of solution solution solution ature steam (° C.) (atm) (g/min) (° C.) sprayed Example 180 10 0.2 450 0.60 1 Example 180 10 0.2 500 0.35 2

[0197] Streams 1-3 obtained were analyzed, and the concentration of total lactic acid compounds in the 1-3 stream and the ratio of oligomers among them were measured and calculated, which are summarized in Table 5 below.

TABLE-US-00005 TABLE 5 Temperature of the Concentration 1-3 stream of lactic Ratio of (° C.) acid (wt. %) oligomer Example 1 180 19 0.04 Example 2 180 9 0.03

[0198] Referring to Table 5, it can be clearly confirmed that according to Examples of the present disclosure, lactic acid was continuously vaporized to reduce the content of lactic acid oligomer in a very short period of time.

<Second Example> Example of 2620KR; 4839KR

[0199] Separately from this, a lactic acid aqueous solution having the concentration as summarized in Table 6 below was prepared.

TABLE-US-00006 TABLE 6 Concentration of lactic acid aqueous solution Ratio of initial Temperature Pressure (wt. %) oligomer (° C.) (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

[0200] The concentration of lactic acid aqueous solution, that is, the lactic acid aqueous solution concentration of the feed containing all of lactic acid, lactic acid dimer and lactic acid oligomer was determined by collecting each sample, measuring the carbon content by elemental analysis, and dividing by the ratio of carbon content in lactic acid.

[0201] The ratio of lactic acid oligomer (including dimer) in the lactic acid aqueous solution was calculated by collecting each sample, analyzing the content of lactic acid single molecules through HPLC, and dividing the amount of oligomers by the amount of total lactic acid-based compounds from the concentration of the aqueous lactic acid solution and the content of single molecules.

[0202] Next, an apparatus for vaporizing lactic acid, comprising: a feed supply section that supplies a 3-1 stream containing an aqueous lactic acid solution; a steam supply section that supplies a 3-2 stream containing a steam; a vaporization reaction section that receives supply of a 3-1 stream from the feed supply section and receives supply of a 3-2 stream from the steam supply section to perform a vaporization reaction of an aqueous lactic acid solution; and an obtaining section that obtains a 3-3 stream containing vaporized lactic acid molecules, was prepared.

[0203] A thermometer and a temperature control device were provided in the feed supply section and the steam supply section, whereby the temperature of the supplied feed (3-1 stream) and water vapor (3-2 stream) can be adjusted. The obtaining section was equipped with a thermometer to measure the temperature of the 3-3 stream.

[0204] First, steam was charged into the vaporization reactor so that the interior of the vaporization reactor was saturated with steam.

[0205] Then, the lactic acid aqueous solution according to Examples 1 to 7 was supplied to the 3-1 stream through the feed supply section, the steam was supplied through the steam supply section, and continuously mixed and sprayed into the inside of the vaporization reaction section through each nozzle. Thereby, the 3-3 stream containing vaporized lactic acid molecules was obtained through the obtaining section.

[0206] The spray conditions are as summarized in Table 6 below.

TABLE-US-00007 TABLE 6 Spray Temperature Pressure of amount of of lactic lactic acid lactic acid Steam Spray acid aqueous aqueous aqueous temper- amount of solution solution solution ature steam (° C.) (atm) (g/min) (° C.) (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

[0207] Streams 3-3 obtained were analyzed, and the concentration of total lactic acid compounds in the 3-3 stream and the ratio of oligomers among them were measured and calculated, which are summarized in Table 8 below.

TABLE-US-00008 TABLE 8 Temperature of the 3-3 Concentration stream of lactic Ratio of (° C.) acid (wt. %) oligomer 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

[0208] Referring to Table 8, it can be clearly confirmed that according to Examples of the present disclosure, lactic acid was continuously vaporized to reduce the content of lactic acid oligomer in a very short period of time.

DESCRIPTION OF REFERENCE NUMERALS

[0209] 1: 3-1 stream; 2: 3-2 stream; [0210] 3: 3-3 stream; 100: feed supply section; [0211] 110: lactic acid aqueous solution feed; 120: feed pretreatment section; [0212] 200: steam supply section; 210: water supply section; [0213] 220: water pretreatment section; 300: vaporization reaction section; [0214] 310: spray section; 400: obtaining section; [0215] 410: gas-liquid separator; 111, 121, 211, 221: flow regulator (valve)