An acetaldehyde recovery device and method in the production of 1,3-butanediol.

Abstract

This application discloses an acetaldehyde recovery device and method in the production of 1,3-butanediol, belonging to the field of fine chemicals. The device includes: a feed pump, a preheater, a distillation column, a falling film reboiler, a bottom circulating pump, a bottom cooler, a top primary condenser, a reflux ratio distributor, a top secondary condenser, a top product tank, a top transfer tank, a bottom product tank, a bottom transfer tank, a vacuum condenser, a vacuum pump inlet separator, a high vacuum unit, and a vacuum pump outlet separator. The horizontal condenser is directly installed at the top of the distillation column, giving it advantages such as simple structure, convenient operation, low pipeline loss, and high vacuum. A method for acetaldehyde recovery in the production of 1,3-butanediol using this device is also disclosed. Compared to existing technologies, this invention uses falling film evaporation combined with vacuum deep cooling, which avoids the thermal decomposition of 3-hydroxybutyraldehyde and achieves low-temperature, high-efficiency acetaldehyde recovery. It is suitable for continuous production.

Description

Technical Field

[0001] This application relates to an acetaldehyde recovery device and method in the production of 1,3-butanediol, which belongs to the field of fine chemicals. Background Technology

[0002] 1,3-Butylene Glycol (1,3-BDO) is a widely used chemical product with high added value and a gradually expanding market. Currently, the mainstream process for producing 1,3-butylene glycol uses acetaldehyde as a raw material. First, a water-soluble liquid alkali such as NaOH is used as a catalyst to induce a self-condensation reaction in an aqueous solution to produce 3-hydroxybutyraldehyde. Then, using Raney nickel as a catalyst, hydrogenation is carried out to produce 1,3-butylene glycol. In the acetaldehyde condensation and hydrogenation process for producing 1,3-butylene glycol, a large amount of acetaldehyde is generated after the first condensation reaction, requiring recovery. Existing technologies employ various methods to recover and utilize acetaldehyde. For example, CN112390713A reported a method for recovering acetaldehyde using nitrogen stripping and pressurized cooling; CN111704532A reported that low-temperature and high-efficiency acetaldehyde recovery can be achieved by using the combined effect of a bubble column and an absorption column; CN105585448A reported the flash evaporation recovery of acetaldehyde at a temperature of 80-100℃ after condensation reaction. Summary of the Invention

[0003] To address the problems of low acetaldehyde recovery rate and high energy consumption in existing technologies, this invention employs a falling film evaporation combined with depressurized deep cryogenic treatment, which can efficiently recover acetaldehyde while ensuring the stable presence of 3-hydroxybutyraldehyde, making it suitable for continuous industrial production.

[0004] According to the first aspect of this application, an acetaldehyde recovery device is provided in the production process of 1,3-butanediol.

[0005] An acetaldehyde recovery device for the production of 1,3-butanediol, the device comprising:

[0006] Feed pump, preheater, distillation column, falling film reboiler, bottom circulating pump, bottom cooler, top primary condenser, reflux distributor, top secondary condenser, top product tank, top transfer tank, bottom product tank, bottom transfer tank, vacuum condenser, vacuum pump inlet separator, high-efficiency vacuum pump.

[0007] Empty unit, vacuum pump outlet separator.

[0008] Optionally, the feed pump is connected to a preheater, and the preheater is connected to the middle section of the distillation column;

[0009] The falling film reboiler is connected to the lower part of the distillation column;

[0010] The falling film reboiler is connected to the bottom circulation pump of the tower.

[0011] The bottom circulation pump is connected to the bottom of the distillation column;

[0012] The bottom cooler is connected to the bottom circulation pump, the bottom product tank is connected to the bottom cooler, and the bottom transfer tank is connected to the bottom product tank.

[0013] The first-stage condenser at the top of the column is directly installed at the top of the distillation column;

[0014] The reflux ratio distributor is connected to the top of the distillation column, the top secondary condenser is connected to the reflux ratio distributor, the top product tank is connected to the top secondary condenser, and the top transfer tank is connected to the top product tank.

[0015] The vacuum condenser is connected to the first-stage condenser at the top of the tower, the product tank at the top of the tower, and the product tank at the bottom of the tower. The vacuum pump inlet separator is connected to the vacuum condenser. The high vacuum unit is connected to the vacuum pump inlet separator. The vacuum pump outlet separator is connected to the high vacuum unit.

[0016] Optionally, the falling film reboiler is used to heat the bottom of the distillation column;

[0017] The falling film reboiler is heated by a thermal oil furnace, and the mixture flows from top to bottom along the inner wall of the falling film tube in a thin film state through a bottom circulation pump.

[0018] The bottom of the distillation column is heated by a falling film reboiler, which is heated by a thermal oil heater. The mixture flows from top to bottom along the inner wall of the falling film tube in a thin film state through a bottom circulation pump. This results in a high heat transfer coefficient, short material residence time, and avoids the decomposition of 3-hydroxybutyraldehyde.

[0019] Optionally, the top-stage condenser is a horizontal condenser, directly installed at the top of the distillation column. It features simple structure, convenient operation, low pipeline losses, and high vacuum.

[0020] Optionally, the distillation column is a packed column with a total packing height of 2.5~4m.

[0021] Optionally, the total height of the packing is 3m, and the heights of the rectifying section and the stripping section are each 1.5m.

[0022] Optionally, the packing type is BX500.

[0023] Optionally, the first-stage condenser and the second-stage condenser at the top of the tower are cooled by a refrigeration unit.

[0024] Optionally, the distillation column is equipped with a reflux ratio distributor at the top, with the reflux ratio adjustable from 0 to 99% full reflux.

[0025] Optionally, the device is equipped with a high vacuum unit with an ultimate vacuum of less than 50 Pa.

[0026] Optionally, the inlet and outlet separators of the high-vacuum unit within the device are both cooled by a jacketed refrigeration unit.

[0027] Protect the vacuum pump.

[0028] According to a second aspect of this application, a method for acetaldehyde recovery during the production of 1,3-butanediol is provided.

[0029] A method for acetaldehyde recovery in the production of 1,3-butanediol, comprising the use of the aforementioned acetaldehyde recovery device for the production of 1,3-butanediol, including:

[0030] S1. Cool the mixture containing acetaldehyde and 3-hydroxybutyraldehyde to 5~10℃;

[0031] S2. The mixture is pumped to the preheater and preheated before entering the middle of the distillation column. The temperature of the preheater is controlled at 15~25℃.

[0032] S3. Control the bottom temperature of the distillation column to 40~70℃, the frequency converter output of the bottom circulation pump to 60~80, the top temperature to 30~60℃, and the top pressure to 10~40KPa.

[0033] S4. Control the outlet temperature of the first-stage condenser at the top of the column to -30~-10℃, the reflux ratio to 10~40, and the temperature of the second-stage condenser at the top of the column to -25℃~-15℃. At this time, acetaldehyde is collected in the product tank at the top of the column and transferred through the intermediate tank at the top of the column. 3-hydroxybutyraldehyde is collected in the product tank at the bottom of the column and transferred through the product tank at the bottom of the column.

[0034] The beneficial effects that this application can produce include:

[0035] The acetaldehyde recovery device and method provided in this application for the 1,3-butanediol production process can avoid the thermal decomposition of 3-hydroxybutyraldehyde and achieve low-temperature and efficient acetaldehyde recovery. The acetaldehyde recovery rate is higher than 90%, and the 3-hydroxybutyraldehyde retention rate is higher than 97%. The product quality meets industrial requirements and is suitable for continuous production. Attached Figure Description

[0036] Figure 1 This is a flowchart of an acetaldehyde recovery device in the 1,3-butanediol production process according to one embodiment of this application.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1-Raw material pump 2-Preheater 3-Distillation column

[0039] 4-Falling film reboiler; 5-Bottom circulation pump; 6-Bottom cooler

[0040] 7-Top-stage condenser; 8-Reflux ratio distributor; 9-Top-stage condenser

[0041] 10-Top product tank; 11-Top transfer tank

[0042] 12-Bottom Product Tank 13-Bottom Transfer Tank

[0043] 14-Vacuum condenser; 15-Vacuum pump inlet separator.

[0044] 16 High vacuum unit 17 Vacuum pump outlet separator Detailed Implementation

[0045] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments. The endpoints of the ranges and any values ​​disclosed herein are not limited to those precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to those ranges or values. These numerical ranges should be considered as specifically disclosed herein.

[0046] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0047] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0048] As one specific implementation, an acetaldehyde recovery device for the production of 1,3-butanediol includes: a feed pump, a preheater, a distillation column, a falling film reboiler, a bottom circulation pump, a bottom cooler, a top primary condenser, a reflux ratio distributor, a top secondary condenser, a top product tank, a top transfer tank, a bottom product tank, a bottom transfer tank, a vacuum condenser, a vacuum pump inlet separator, a high vacuum unit, and a vacuum pump outlet separator.

[0049] Furthermore, the feed pump is connected to the preheater, and the preheater is connected to the middle section of the distillation column; the falling film reboiler is connected to the lower section of the distillation column; the falling film reboiler is connected to the bottom circulation pump; the bottom circulation pump is connected to the bottom of the distillation column; the bottom cooler is connected to the bottom circulation pump; the bottom product tank is connected to the bottom cooler; the bottom transfer tank is connected to the bottom product tank; the top primary condenser is directly installed at the top of the distillation column; the reflux ratio distributor is connected to the upper section of the distillation column; the top secondary condenser is connected to the reflux ratio distributor; the top product tank is connected to the top secondary condenser; the top transfer tank is connected to the top product tank; the vacuum condenser is connected to the top primary condenser, the top product tank, and the bottom product tank; the vacuum pump inlet separator is connected to the vacuum condenser; the high vacuum unit is connected to the vacuum pump inlet separator; and the vacuum pump outlet separator is connected to the high vacuum unit.

[0050] Furthermore, the distillation column is a packed column, with BX500 packing type and a total packing height of [missing information].

[0051] The distillation section is 3m high, and the rectification section and stripping section are each 1.5m high.

[0052] Furthermore, the bottom of the distillation column is heated by a falling film reboiler, which is heated by a thermal oil heater. The mixture flows from top to bottom along the inner wall of the falling film tube in a thin film state through a bottom circulation pump. This results in a high heat transfer coefficient, short material residence time, and avoidance of the decomposition of 3-hydroxybutyraldehyde.

[0053] Furthermore, the first-stage condenser at the top of the column is a horizontal condenser, which is directly installed at the top of the distillation column. It features simple structure, convenient operation, low pipeline loss, and high vacuum.

[0054] Furthermore, the distillation column is equipped with a reflux ratio distributor at the top, with the reflux ratio adjustable from 0 to 99% full reflux.

[0055] As a specific implementation method, an acetaldehyde recovery method in the production process of 1,3-butanediol uses the aforementioned acetaldehyde recovery device for the production process of 1,3-butanediol for separation, as detailed below:

[0056] (1) Cool the mixture, which mainly contains acetaldehyde and 3-hydroxybutyraldehyde, to 5~10℃;

[0057] (2) The mixture is pumped to the preheater and preheated before entering the middle of the distillation column. The temperature of the preheater is controlled at 15~25℃.

[0058] (3) Control the bottom temperature of the distillation column to 40~70℃, the frequency conversion output of the circulating pump to 60~80℃, the top temperature of the column to 30~60℃, and the top pressure of the column to 10~40KPa.

[0059] (4) Control the outlet temperature of the first-stage condenser at the top of the tower to -30~-10℃, the reflux ratio to 10~40, and the temperature of the second-stage condenser at the top of the tower to -25℃~-15℃. At this time, acetaldehyde is collected in the product tank at the top of the tower and transferred through the transfer tank at the top of the tower. 3-hydroxybutyraldehyde is collected in the product tank at the bottom of the tower and transferred through the product tank at the bottom of the tower.

[0060] The mixture contains acetaldehyde and 3-hydroxybutyraldehyde, which are products of a condensation reaction. The acetaldehyde concentration is 5-80%, the 3-hydroxybutyraldehyde concentration is 15-60%, and the content of other substances is 3%-40%.

[0061] The analysis method in the embodiments of this application is as follows:

[0062] The water and acid content in the recovered acetaldehyde can be quantitatively analyzed by gas chromatography, and the concentrations of acetaldehyde and 3-hydroxybutyraldehyde in the material can be determined by the standard curve method.

[0063] The acetaldehyde recovery rate is (acetaldehyde in the top product of the distillation column / acetaldehyde in the mixture) × 100%, and the 3-hydroxybutyraldehyde retention rate is (3-hydroxybutyraldehyde in the bottom product of the distillation column / 3-hydroxybutyraldehyde in the mixture).

[0064] Example 1

[0065] like Figure 1 The diagram shows a flowchart of an acetaldehyde recovery unit in the production of 1,3-butanediol. The unit includes: a feed pump 1, a preheater 2, a distillation column 3, a falling film reboiler 4, a bottom circulation pump 5, a bottom cooler 6, a top primary condenser 7, a reflux ratio distributor 8, a top secondary condenser 9, a top product tank 10, a top transfer tank 11, a bottom product tank 12, a bottom transfer tank 13, a vacuum condenser 14, a vacuum pump inlet separator 15, a high vacuum unit 16, and a vacuum pump outlet separator 17.

[0066] The feed pump 1 is connected to the preheater 2, the preheater 2 is connected to the middle part of the distillation column 3, the falling film reboiler 4 and the bottom circulation pump 5 are connected to the lower part of the distillation column 3, the bottom cooler 6 is connected to the bottom circulation pump 5, the bottom product tank 12 is connected to the bottom cooler 6, the bottom transfer tank 13 is connected to the bottom product tank 12, the top primary condenser 7 is directly installed at the top of the distillation column 3, the reflux ratio distributor 8 is connected to the upper part of the column, the top secondary condenser 9 is connected to the reflux ratio distributor 8, and the top product tank 10 is connected to the top secondary condenser 9. The transfer tank 11 at the top of the tower is connected to the product tank 10 at the top of the tower. The vacuum condenser 14 is connected to the first-stage condenser 7 at the top of the tower, the product tank 10 at the top of the tower, and the product tank 12 at the bottom of the tower. The vacuum pump inlet separator 15 is connected to the vacuum condenser 14. The high vacuum unit 16 is connected to the vacuum pump inlet separator 15. The vacuum pump outlet separator 17 is connected to the high vacuum unit 16.

[0067] The distillation column 3 is a packed column with BX500 packing. The total height of the packing is 3m, and the height of the rectification section and the stripping section are both 1.5m.

[0068] The first-stage condenser 7 at the top of the column is a horizontal condenser, which is directly installed at the top of the distillation column. It features simple structure, convenient operation, low pipeline loss, and high vacuum.

[0069] The first-stage condenser 7 and the second-stage condenser 9 at the top of the tower are cooled by a refrigeration unit.

[0070] The bottom of the distillation column 3 is heated by a falling film reboiler 4, which is heated by a thermal oil heater. The mixture flows from top to bottom along the inner wall of the falling film tube in a thin film state through the bottom circulation pump 5. This results in a high heat transfer coefficient, short material residence time, and avoidance of the decomposition of 3-hydroxybutyraldehyde.

[0071] The device is equipped with a high vacuum unit 16, with an ultimate vacuum degree of less than 50 Pa.

[0072] The inlet and outlet liquid separators (vacuum pump inlet liquid separator 15 and vacuum pump outlet liquid separator 17) of the high vacuum unit 16 are all cooled by a refrigeration jacket to protect the vacuum pump.

[0073] The distillation column 3 is equipped with a reflux ratio distributor 8 at the top, with a reflux ratio adjustable from 0 to 99% for total reflux.

[0074] Example 2

[0075] A method for acetaldehyde recovery in the production of 1,3-butanediol, using the 1,3-butanediol method described in Example 1.

[0076] Acetaldehyde is separated during the glycol production process using a recovery unit, as detailed below:

[0077] (1) The mixture contains 45% acetaldehyde, 50% 3-hydroxybutyraldehyde, and 5% other substances. The mixture is cooled to 10°C and then pumped to preheater 2 using raw material pump 1.

[0078] After the preheater 2 is heated to 20°C, it enters from the middle of the distillation column 3, and the feed rate of the mixture is 5 kg / h.

[0079] (2) Put the bottom circulation pump 5 into operation, with the frequency converter set at 70%. Put the first-stage condenser 7 into operation at the top of the column, with the temperature set at -30℃. Put the second-stage condenser 9 into operation at the top of the column, with the temperature set at -25℃. Start the high vacuum unit 16 and control the pressure of the distillation column 3 to 30 kPa. Control the reflux ratio to 30 through the reflux ratio distributor 8.

[0080] (3) Put the heat transfer oil unit into operation and control the bottom temperature of distillation column 3 to 60℃.

[0081] (4) Control the top temperature of distillation column 3 to 43℃.

[0082] (5) A large amount of acetaldehyde gas evaporates from the bottom mixture of the distillation column 3 and comes into countercurrent contact with the reflux liquid phase from bottom to top. The gas and liquid phases continuously transfer mass and heat until they reach equilibrium.

[0083] (6) The water and acid content in the recovered acetaldehyde were quantitatively analyzed by gas chromatography. The concentrations of acetaldehyde and 3-hydroxybutyraldehyde in the material could be determined by the standard curve method. The purity of the recovered acetaldehyde was ≥99%. The amount of recyclable acetaldehyde was 2 kg / h, and the acetaldehyde recovery rate was 90%. The amount of 3-hydroxybutyraldehyde at the bottom of the tower was 2.4 kg / h, and the retention rate of 3-hydroxybutyraldehyde was ≥97%.

[0084] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An acetaldehyde recovery device in the production process of 1,3-butanediol, characterized in that, The device includes: Raw material pumps, preheaters, distillation columns, falling film reboilers, bottom circulating pumps, bottom coolers, top primary condensers, reflux distributors, top secondary condensers, top product tanks, top transfer tanks, bottom product tanks, bottom transfer tanks, vacuum condensers, vacuum pump inlet separators, high vacuum units, and vacuum pump outlet separators; The raw material pump is connected to the preheater, and the preheater is connected to the middle part of the distillation column; The falling film reboiler is connected to the lower part of the distillation column; The falling film reboiler is connected to the bottom circulation pump of the tower. The bottom circulation pump is connected to the bottom of the distillation column; The bottom cooler is connected to the bottom circulation pump, the bottom product tank is connected to the bottom cooler, and the bottom transfer tank is connected to the bottom product tank. The first-stage condenser at the top of the column is directly installed at the top of the distillation column; The reflux ratio distributor is connected to the top of the distillation column, the top secondary condenser is connected to the reflux ratio distributor, the top product tank is connected to the top secondary condenser, and the top transfer tank is connected to the top product tank. The vacuum condenser is connected to the first-stage condenser at the top of the tower, the product tank at the top of the tower, and the product tank at the bottom of the tower. The vacuum pump inlet separator is connected to the vacuum condenser. The high vacuum unit is connected to the vacuum pump inlet separator. The vacuum pump outlet separator is connected to the high vacuum unit.

2. The apparatus according to claim 1, characterized in that, The falling film reboiler is used to heat the bottom of the distillation column; The falling film reboiler is heated by a thermal oil furnace, and the mixture flows from top to bottom along the inner wall of the falling film tube in a thin film state through a bottom circulation pump.

3. The apparatus according to claim 1, characterized in that, The first-stage condenser at the top of the column is a horizontal condenser, which is directly installed on the top of the distillation column.

4. The apparatus according to claim 1, characterized in that, The distillation column is a packed column with a total packing height of 2.5~4m.

5. The apparatus according to claim 4, characterized in that, The total height of the packing is 3m, and the heights of the rectification section and the stripping section are each 1.5m.

6. The apparatus according to claim 4, characterized in that, The packing type is BX500.

7. The apparatus according to claim 1, characterized in that, The first-stage condenser and the second-stage condenser at the top of the tower are cooled by a refrigeration unit.

8. The apparatus according to claim 1, characterized in that, The distillation column is equipped with a reflux ratio distributor at the top, with the reflux ratio adjustable from 0 to 99% full reflux.

9. The apparatus according to claim 1, characterized in that, The device is equipped with a high vacuum unit with an ultimate vacuum of less than 50 Pa.

10. The apparatus according to claim 1, characterized in that, The inlet and outlet separators of the high vacuum unit inside the device are cooled by a refrigeration jacket to protect the vacuum pump.

11. A method for acetaldehyde recovery during the production of 1,3-butanediol, characterized in that: The acetaldehyde recovery device used in the 1,3-butanediol production process according to any one of claims 1 to 10 is used for separation, comprising: S1. Cool the mixture containing acetaldehyde and 3-hydroxybutyraldehyde to 5~10℃; S2. The mixture is pumped to the preheater and preheated before entering the middle of the distillation column. The temperature of the preheater is controlled at 15~25℃. S3. Control the bottom temperature of the distillation column to 40~70℃, the frequency converter output of the bottom circulation pump to 60~80, the top temperature to 30~60℃, and the top pressure to 10~40KPa. S4. Control the outlet temperature of the first-stage condenser at the top of the column to -30~-10℃, the reflux ratio to 10~40, and the temperature of the second-stage condenser at the top of the column to -25℃~-15℃. At this time, acetaldehyde is collected in the product tank at the top of the column and transferred through the intermediate tank at the top of the column. 3-hydroxybutyraldehyde is collected in the product tank at the bottom of the column and transferred through the product tank at the bottom of the column.

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