Methyl acetate / methanol low-boiling-point mixed solution decompression separation device and method

Abstract

The invention discloses a methyl acetate / methanol low-boiling-point mixed solution decompression separation device and method, and the separation device comprises a heating container which is used for heating and vaporizing a low-boiling-point mixed solution; the rectifying tower, the first heat exchange device and the second heat exchange device are sequentially connected; the second heat exchange device is connected with a vacuum pump and used for providing a negative pressure environment. The first heat exchange device is used for collecting a first solute; the second heat exchange device is used for collecting a second solute; the boiling point of the first solute is higher than that of the second solute. The high-efficiency separation of the low-boiling-point mixed liquid under the pressure reduction condition is realized, and the device is simple in structure and high in operation safety.

Description

Technical Field

[0001] The invention relates to the technical field of separation devices, and in particular to a decompression separation device and a method for a methyl acetate / methanol low-boiling point mixed liquid. Background Art

[0002] In chemical production, liquid mixtures are separated by atmospheric distillation, vacuum distillation or supercharged distillation. For existing distillation devices, the separation efficiency of low-boiling-point liquid mixtures (such as a mixture of methyl acetate and methanol, etc.) is low when atmospheric distillation is performed; supercharged distillation has higher requirements on the safety of the equipment, and improper operation is likely to cause safety hazards; vacuum distillation is mainly used for high-boiling-point liquid mixture systems, which can reduce their boiling points or improve the chemical stability of the liquid during the separation process, while the effect of vacuum distillation is poor for the separation of low-boiling-point liquid mixtures. Therefore, the purpose of the present invention is to provide a device with good separation effect on low-boiling-point mixed liquids under reduced pressure conditions. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a device and method for decompressing and separating a methyl acetate / methanol low-boiling point mixed liquid, which realizes efficient separation of the low-boiling point mixed liquid under decompressed conditions.

[0004] The methyl acetate / methanol low boiling point mixed liquid decompression separation device proposed by the present invention comprises: A heating container, used for heating and vaporizing a low-boiling-point mixed liquid; A distillation tower, a first heat exchange device and a second heat exchange device connected in sequence; The second heat exchange device is connected to a vacuum pump for providing a negative pressure environment; The first heat exchange device is used for collecting the first solute; The second heat exchange device is used for collecting the second solute; The boiling point of the first solute is higher than the boiling point of the second solute.

[0005] Preferably, the distillation tower comprises a distillation tube, a filler is arranged in the distillation tube, the bottom of the distillation tube is connected to the heating container, and the upper end of the distillation tube is connected to the first heat exchange device through a connecting pipe and a first feed pipe.

[0006] Preferably, the first heat exchange device includes a first heat exchange chamber, a first heat exchange tube is arranged in the first heat exchange chamber, the first heat exchange tube is connected to a first cooling medium inlet and a first cooling medium outlet, the first heat exchange chamber is connected to the distillation tower through a connecting pipe and a first feed pipe, the top of the first heat exchange chamber is connected to the second heat exchange device through a second feed pipe, and a first discharge pipe is arranged at the bottom of the first heat exchange chamber.

[0007] Preferably, the connecting pipe is also connected to a sampling pipe, and the sampling pipe is provided with a second valve.

[0008] Preferably, the second heat exchange device includes a second heat exchange chamber, a second heat exchange tube is arranged in the second heat exchange chamber, the second heat exchange tube is connected to a second cooling medium outlet and a second cooling medium inlet, the second heat exchange chamber is connected to the first heat exchange device through a second material delivery pipe, a vacuum pump is connected to the top of the second heat exchange chamber, and a second discharge pipe is arranged at the bottom of the second heat exchange chamber.

[0009] Preferably, the vacuum pump is connected to a vacuum pump outlet pipe and a vacuum pump inlet pipe, both the vacuum pump outlet pipe and the vacuum pump inlet pipe are provided with a first valve, the vacuum pump inlet pipe is connected to the second heat exchange device, and a buffer tank is also provided on the vacuum pump inlet pipe, and the buffer tank is located between the vacuum pump and the second heat exchange device.

[0010] Preferably, the vacuum degree of the vacuum pump is not less than -0.05 MPa.

[0011] Preferably, the height of the distillation tower is 2-3 times the height of the first heat exchange device; the height of the second heat exchange device is 1-1.5 times the height of the first heat exchange device.

[0012] The separation method of the methyl acetate / methanol low-boiling point mixed liquid decompression separation device proposed by the present invention comprises the following steps: S1: The low boiling point mixed liquid is heated in a heating container until it vaporizes; S2: The vaporized low-boiling point mixed liquid enters the distillation tower and is decompressed and separated during the heat exchange process; S3: The low-boiling-point mixed liquid treated with reduced pressure enters the first heat exchange device, the first solute is collected at the bottom of the first heat exchange device, the gas in the first heat exchange device is discharged from the top and enters the second heat exchange device, and the second solute is collected by the second heat exchange device.

[0013] Beneficial technical effects of the present invention: The invention realizes efficient separation of low-boiling-point mixed liquid by decompressing the vaporized low-boiling-point mixed liquid in the condensation heat exchange stage; the separation device has the advantages of simple structure, good separation effect and high safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of the methyl acetate / methanol low-boiling point mixed liquid decompression separation device proposed by the present invention; Figure 2 A chromatogram of the material collected by the first heat exchange device proposed by the present invention; Figure 3 This is a chromatogram of the material collected by the second heat exchange device proposed by the present invention.

[0015] In the figure: 1-heating container, 2-first cooling medium outlet, 3-filler, 4-distillation tower, 5-buffer tank, 6-first valve, 7-vacuum pump, 8-vacuum pump outlet pipe, 9-vacuum pump inlet pipe, 10-first feed pipe, 11-first heat exchange device, 12-first heat exchange cavity, 13-first heat exchange tube, 14-first cooling medium inlet, 15-connecting pipe, 16-sampling tube, 17-second valve, 18-second heat exchange cavity, 19-second cooling medium outlet, 20-second heat exchange tube, 21-second heat exchange device, 22-second cooling medium inlet, 23-second feed pipe, 24-distillation tube. DETAILED DESCRIPTION

[0016] The present invention will be further explained below in conjunction with specific embodiments.

[0017] Reference Figure 1 The methyl acetate / methanol low-boiling point mixed liquid decompression separation device proposed by the present invention comprises: a heating container 1, which is used for heating and vaporizing the low-boiling point mixed liquid; a distillation tower 4, a first heat exchange device 11 and a second heat exchange device 21 connected in sequence; the second heat exchange device 21 is connected to a vacuum pump 7, and the vacuum degree of the vacuum pump 7 is not less than -0.05MPa, which is used to provide a negative pressure environment; the first heat exchange device 11 is used for collecting a first solute; the second heat exchange device 21 is used for collecting a second solute; the boiling point of the first solute is higher than the boiling point of the second solute; wherein the height of the distillation tower is 3 times the height of the first heat exchange device; the height of the second heat exchange device is 1.5 times the height of the first heat exchange device.

[0018] Specifically, the distillation tower 4 includes a distillation pipe 24, in which a filler 3 is arranged, the bottom of the distillation pipe 24 is connected to the heating container 1, and the upper end of the distillation pipe 24 is connected to the first heat exchange device 11 through a connecting pipe 15 and a first feed pipe 10; one end of the first feed pipe 10 is connected to the first heat exchange device 11 at a height of 1 / 3, and the other end of the first feed pipe 10 is connected to the top of the distillation pipe 24; the connecting pipe 15 is connected to the bottom of the first heat exchange device 11.

[0019] The first heat exchange device 11 includes a first heat exchange chamber 12, in which a first heat exchange tube 13 is arranged, and the first heat exchange tube 13 is connected to a first cooling medium inlet 14 and a first cooling medium outlet 2. The first heat exchange chamber 12 is connected to the distillation tower 4 through a connecting pipe 15 and a first feed pipe 10, and the top of the first heat exchange chamber 12 is connected to the second heat exchange device 21 through a second feed pipe 23, and a first discharge pipe is arranged at the bottom of the first heat exchange chamber 12.

[0020] The second heat exchange device 21 includes a second heat exchange chamber 18, in which a second heat exchange tube 20 is arranged, and the second heat exchange tube 20 is connected to a second cooling medium outlet 19 and a second cooling medium inlet 22. The second heat exchange chamber 18 is connected to the first heat exchange device 11 through a second delivery pipe 23. The top of the second heat exchange chamber 18 is connected to a vacuum pump 7, and the bottom of the second heat exchange chamber 18 is provided with a second discharge pipe.

[0021] The vacuum pump 7 is connected to a vacuum pump outlet pipe 8 and a vacuum pump inlet pipe 9, both of which are provided with a first valve 6, the vacuum pump inlet pipe 9 is connected to the second heat exchange device 21, and a buffer tank 5 is also provided on the vacuum pump inlet pipe 9, and the buffer tank 5 is located between the vacuum pump 7 and the second heat exchange device 21.

[0022] In order to facilitate sampling and testing, the connecting tube 15 is further connected to a sampling tube 16 , and the sampling tube 16 is provided with a second valve 17 .

[0023] The heat exchange medium used in the heat exchange device of the present invention can be condensed water, salt water, or other industrial condensing agents.

[0024] Taking methyl acetate-methanol low boiling point liquid mixture (volume ratio of 1:3) as the separation object, decompression separation was carried out under a vacuum degree of -0.06MPa. It was determined that the purity of methanol collected by the first heat exchange device was 100% (such as Figure 2 As shown, the 1.0 peak is a water peak, the 2.0 peak is a methanol peak, and there is no methyl acetate peak); the purity of methyl acetate collected by the second heat exchange device is more than 95% (such as Figure 3 As shown, the 1.0 peak is the water peak, the 2.0 peak is the methanol peak, and the 7.0 peak is the methyl acetate peak).

Claims

1. A methyl acetate / methanol low boiling point mixed liquid decompression separation device, characterized in that: include: A heating container (1) is used for heating and vaporizing a low-boiling-point mixed liquid; A distillation tower (4), a first heat exchange device (11) and a second heat exchange device (21) connected in sequence; The second heat exchange device (21) is connected to a vacuum pump (7) for providing a negative pressure environment; The first heat exchange device (11) is used to collect the first solute; The second heat exchange device (21) is used for collecting the second solute; The boiling point of the first solute is higher than the boiling point of the second solute.

2. The methyl acetate / methanol low boiling point mixed liquid decompression separation device according to claim 1, characterized in that: The distillation tower (4) comprises a distillation tube (24), a filler (3) is arranged in the distillation tube (24), the bottom of the distillation tube (24) is connected to the heating container (1), and the upper end of the distillation tube (24) is connected to the first heat exchange device (11) via a connecting tube (15) and a first feed pipe (10).

3. The methyl acetate / methanol low boiling point mixed liquid decompression separation device according to claim 1, characterized in that: The first heat exchange device (11) comprises a first heat exchange chamber (12), a first heat exchange tube (13) being arranged in the first heat exchange chamber (12), the first heat exchange tube (13) being connected to a first cooling medium inlet (14) and a first cooling medium outlet (2), the first heat exchange chamber (12) being connected to the distillation tower (4) via a connecting tube (15) and a first material delivery pipe (10), the top of the first heat exchange chamber (12) being connected to the second heat exchange device (21) via a second material delivery pipe (23), and a first discharge pipe being arranged at the bottom of the first heat exchange chamber (12).

4. The methyl acetate / methanol low boiling point mixed liquid decompression separation device according to claim 2 or 3, characterized in that: The connecting tube (15) is also connected to a sampling tube (16), and the sampling tube (16) is provided with a second valve (17).

5. The methyl acetate / methanol low boiling point mixed liquid decompression separation device according to claim 1, characterized in that: The second heat exchange device (21) comprises a second heat exchange chamber (18), a second heat exchange tube (20) is arranged in the second heat exchange chamber (18), the second heat exchange tube (20) is connected to a second cooling medium outlet (19) and a second cooling medium inlet (22), the second heat exchange chamber (18) is connected to the first heat exchange device (11) via a second delivery pipe (23), the top of the second heat exchange chamber (18) is connected to a vacuum pump (7), and the bottom of the second heat exchange chamber (18) is provided with a second discharge pipe.

6. The methyl acetate / methanol low boiling point mixed liquid decompression separation device according to claim 1, characterized in that: The vacuum pump (7) is connected to a vacuum pump outlet pipe (8) and a vacuum pump inlet pipe (9), and both the vacuum pump outlet pipe (8) and the vacuum pump inlet pipe (9) are provided with a first valve (6). The vacuum pump inlet pipe (9) is connected to the second heat exchange device (21), and a buffer tank (5) is also provided on the vacuum pump inlet pipe (9), and the buffer tank (5) is located between the vacuum pump (7) and the second heat exchange device (21).

7. The methyl acetate / methanol low boiling point mixed liquid decompression separation device according to claim 1, characterized in that: The vacuum degree of the vacuum pump (7) is not less than -0.05 MPa.

8. The methyl acetate / methanol low boiling point mixed liquid decompression separation device according to claim 1, characterized in that: The height of the distillation tower (4) is 2 to 3 times the height of the first heat exchange device (11); and the height of the second heat exchange device (21) is 1 to 1.5 times the height of the first heat exchange device (11).

9. The separation method of the methyl acetate / methanol low boiling point mixed liquid decompression separation device according to any one of claims 1 to 7, characterized in that: The steps are as follows: S1: The low boiling point mixed liquid is heated in a heating container until it vaporizes; S2: The vaporized low-boiling point mixed liquid enters the distillation tower and is decompressed and separated during the heat exchange process; S3: The low-boiling-point mixed liquid treated with reduced pressure enters the first heat exchange device, the first solute is collected at the bottom of the first heat exchange device, the gas in the first heat exchange device is discharged from the top and enters the second heat exchange device, and the second solute is collected by the second heat exchange device.

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