Sodium carbonate salt removal device for propylene glycol crude product distillation

Abstract

The utility model relates to a sodium carbonate removal device for distilling propylene glycol crude products. According to the technical scheme, one side of a reactive distillation tower is connected with a feeding pipeline, the bottom of the reactive distillation tower is connected to a top inlet of a first falling-film evaporator through a carbonized crude propylene glycol feeding line and a crude propylene glycol feeding pump, and a bottom outlet of the first falling-film evaporator is connected with a buffer tank through a pipeline; the top of the buffer tank is connected to the middle lower side of the propylene glycol light component removal tower through a light component removal line, the bottom of the buffer tank is connected to the plate-and-frame filter press through a pipeline and a feeding pump, and an outlet of the plate-and-frame filter press is connected to the upper side of the propylene glycol light component removal tower through a propylene glycol feeding line. The device has the beneficial effects that water in the system is removed through the falling film evaporator, so that sodium carbonate salt is separated out before entering the light component removal tower, the carrying quantity of the sodium carbonate salt in the system is reduced, the problem of equipment blockage is solved, and meanwhile, the product quality of propylene glycol is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to propylene glycol production technology field in dimethyl carbonate device, especially a kind of sodium carbonate salt removal device for crude propylene glycol distillation. BACKGROUND

[0002] Propylene glycol is a colorless, odorless viscous transparent liquid, is a kind of aliphatic mixture containing two hydroxyl groups. Since the two hydroxyl groups in propylene glycol molecule can all be chemically reacted, therefore, propylene glycol is an important chemical intermediate, has a wide range of applications in many fields such as plastics, clothing, synthetic resin, cosmetics, food, etc., and can also be used as antifreeze, deicing agent, heat transfer medium, liquid detergent, etc.

[0003] Industrial production of dimethyl carbonate device is usually produced by ester exchange method 1,2-propanediol production process, the reaction process needs homogeneous catalyst sodium methoxide to participate, after reaction, sodium ion and water, carbon dioxide carry out carbonization reaction to produce sodium carbonate salt and precipitate. Its existing problem is: in the production process, sodium carbonate salt often appears the problem such as poor filtering effect, etc. to cause sodium carbonate salt to plug equipment, and then affect propylene glycol product quality. UTILITY MODEL CONTENT

[0004] The utility model is just aimed at the above-mentioned defects existing in prior art, provide a kind of sodium carbonate salt removal device for crude propylene glycol distillation, can effectively, practical, industrialized removal sodium carbonate salt, improve the quality of propylene glycol product.

[0005] The utility model discloses a kind of sodium carbonate salt removal device for crude propylene glycol distillation, its technical scheme is: including propylene glycol light removal column (1), first falling film evaporator (2), buffer tank (3), feed pump (4), plate-frame filter press (5), carbonized crude propylene glycol feed line (6), light removal line (7), propylene glycol feed line (8), reaction rectification tower (9), crude propylene glycol feed pump (10), the side of reaction rectification tower (9) is connected feed pipeline, the bottom of reaction rectification tower (9) is connected to the top inlet of first falling film evaporator (2) by carbonized crude propylene glycol feed line (6) and crude propylene glycol feed pump (10), the bottom outlet of first falling film evaporator (2) is connected buffer tank (3) by pipeline, the top of buffer tank (3) is connected to the middle-lower side of propylene glycol light removal column (1) by light removal line (7), the bottom of buffer tank (3) is connected to plate-frame filter press (5) by pipeline and feed pump (4), the outlet of plate-frame filter press (5) is connected to the upper side of propylene glycol light removal column (1) by propylene glycol feed line (8).

[0006] Preferably, the bottom of the above-mentioned reaction rectification tower (9) is installed reboiler.

[0007] Preferably, the first falling film evaporator (2) is connected with a second falling film evaporator (11) in parallel.

[0008] Preferably, the first falling film evaporator (2) is connected with a second falling film evaporator (11) in parallel.

[0009] Preferably, the first falling film evaporator (2) is connected with a second falling film evaporator (11) in parallel.

[0010] Preferably, the first falling film evaporator (2) is connected with a second falling film evaporator (11) in parallel.

[0011] The propylene glycol crude of the utility model is increased with falling film evaporator before entering the light removal tower, and the falling film evaporator is distilled under negative pressure, and the light component in the crude product is flashed and enters the light removal tower from the top of the buffer tank, and the propylene glycol crude with less water content is obtained at the bottom, and because the water content is reduced, the sodium carbonate salt produced in the carbonization process is precipitated in the buffer tank, and continues to enter the plate and frame filter press for pressure filtration, and the sodium carbonate salt is further removed before entering the light removal tower, so that the carrying amount of sodium carbonate salt in the system is reduced, not only the equipment blockage problem is solved, but also the product quality of propylene glycol is improved.

[0012] The propylene glycol crude of the utility model is increased with falling film evaporator before entering the light removal tower, and the falling film evaporator is distilled under negative pressure, and the light component in the crude product is flashed and enters the light removal tower from the top of the buffer tank, and the propylene glycol crude with less water content is obtained at the bottom, and because the water content is reduced, the sodium carbonate salt produced in the carbonization process is precipitated in the buffer tank, and continues to enter the plate and frame filter press for pressure filtration, and the sodium carbonate salt is further removed before entering the light removal tower, so that the carrying amount of sodium carbonate salt in the system is reduced, not only the equipment blockage problem is solved, but also the product quality of propylene glycol is improved. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is the flow schematic diagram of the embodiment 1 of the utility model;

[0014] Figure 2 It is the flow schematic diagram of the embodiment 2 of the utility model;

[0015] Figure 3 It is the flow schematic diagram of the embodiment 3 of the utility model;

[0016] In the drawing: propylene glycol light removal tower 1, first falling film evaporator 2, buffer tank 3, feed pump 4, plate and frame filter press 5, carbonized crude propylene glycol feed line 6, light removal line 7, propylene glycol feed line 8, reaction rectification tower 9, crude propylene glycol feeding pump 10, second falling film evaporator 11, first control valve 12, second control valve 13, third control valve 14, fourth control valve 15, cleaning line 16, cleaning pump 17, clean water tank 18. DETAILED DESCRIPTION

[0017] The preferred embodiments of the utility model are described below in combination with the drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the utility model, and are not used to limit the utility model.

[0018] Embodiment 1, refer to Figure 1 The utility model discloses a sodium carbonate salt removal device for propylene glycol crude distillation, including propylene glycol light removal column 1, falling film evaporator 2, buffer tank 3, feed pump 4, plate and frame filter press 5, carbonized crude propylene glycol feed line 6, light removal line 7, propylene glycol feed line 8, reaction rectification tower 9, crude propylene glycol feeding pump 10, one side of reaction rectification tower 9 is connected to the feed line, and the bottom of reaction rectification tower 9 is connected to the top inlet of falling film evaporator 2 through carbonized crude propylene glycol feed line 6 and crude propylene glycol feeding pump 10, and the bottom outlet of falling film evaporator 2 is connected to buffer tank 3 through the pipeline, and the top of buffer tank 3 is connected to the middle and lower side of propylene glycol light removal column 1 through light removal line 7, and the bottom of buffer tank 3 is connected to plate and frame filter press 5 through the pipeline and feed pump 4, and the outlet of plate and frame filter press 5 is connected to the upper side of propylene glycol light removal column 1 through propylene glycol feed line 8.

[0019] Wherein, the bottom of the reaction rectification tower 9 is installed with a reboiler.

[0020] When the utility model is used, the crude propylene glycol after carbonization in reaction rectification tower 9 enters falling film evaporator 2 to heat distillation, and after entering buffer tank 3, the light component methanol and water are removed with the light removal line under negative pressure and enter propylene glycol light removal column 1, and the lower part of buffer tank 3 obtains the sodium carbonate salt turbid solution with higher concentration, which is transferred into plate and frame filter press 5 through feed pump 4 for pressure filtration, and the lower part of plate and frame filter press 5 obtains the precipitated sodium carbonate salt, and the filtered propylene glycol clear liquid is sent into propylene glycol light removal column 1 for further distillation through propylene glycol feed line 8, the utility model utilizes the characteristics that sodium carbonate salt is dissolved in water but not in alcohol, removes the water in the system through falling film evaporator 2, so that the sodium carbonate salt is precipitated before entering the light removal column, reduces the carrying amount of sodium carbonate salt in the system, not only solves the equipment blockage problem, but also improves the product quality of propylene glycol.

[0021] The utility model discloses a kind of sodium carbonate salt removal devices for crude propylene glycol distillation, including propylene glycol light removal column 1, falling film evaporator 2, buffer tank 3, feed pump 4, plate and frame filter press 5, after carbonization crude propylene glycol feed line 6, light removal line 7, propylene glycol feed line 8, reaction rectification tower 9, crude propylene glycol feed pump 10, the side of reaction rectification tower 9 is connected with feed pipeline, the bottom of reaction rectification tower 9 is connected to the top inlet of falling film evaporator 2 by after carbonization crude propylene glycol feed line 6 and crude propylene glycol feed pump 10, the bottom outlet of falling film evaporator 2 is connected buffer tank 3 by pipeline, the top of buffer tank 3 is connected to the middle lower side of propylene glycol light removal column 1 by light removal line 7, the bottom of buffer tank 3 is connected to plate and frame filter press 5 by pipeline and feed pump 4, the outlet of plate and frame filter press 5 is connected to the upper side of propylene glycol light removal column 1 by propylene glycol feed line 8.

[0022] Different from example 1 is:

[0023] Referring to Figure 2 The side of the first falling film evaporator 2 mentioned in the embodiment is connected in parallel with the second falling film evaporator 11, a first control valve 12 is installed on the after carbonization crude propylene glycol feed line 6 connected to the top of the first falling film evaporator 2, and the top of the second falling film evaporator 11 is connected to the after carbonization crude propylene glycol feed line 6 through a second connecting pipeline and a second control valve 13. The bottom of the second falling film evaporator 11 is connected to the buffer tank 3 through a pipeline.

[0024] By adding the second falling film evaporator 11, the embodiment can better meet the use requirements of the site and more flexibly handle maintenance and other issues.

[0025] The utility model discloses a kind of sodium carbonate salt removal devices for crude propylene glycol distillation, including propylene glycol light removal column 1, falling film evaporator 2, buffer tank 3, feed pump 4, plate and frame filter press 5, after carbonization crude propylene glycol feed line 6, light removal line 7, propylene glycol feed line 8, reaction rectification tower 9, crude propylene glycol feed pump 10, the side of reaction rectification tower 9 is connected with feed pipeline, the bottom of reaction rectification tower 9 is connected to the top inlet of falling film evaporator 2 by after carbonization crude propylene glycol feed line 6 and crude propylene glycol feed pump 10, the bottom outlet of falling film evaporator 2 is connected buffer tank 3 by pipeline, the top of buffer tank 3 is connected to the middle lower side of propylene glycol light removal column 1 by light removal line 7, the bottom of buffer tank 3 is connected to plate and frame filter press 5 by pipeline and feed pump 4, the outlet of plate and frame filter press 5 is connected to the upper side of propylene glycol light removal column 1 by propylene glycol feed line 8.

[0026] Different from example 2 is:

[0027] Referring to Figure 3The third control valve 14 is installed on the pipeline of the bottom of the first falling-film evaporator 2, and the cleaning pipeline 16 is connected to the front end of the third control valve 14, the fourth control valve 15 is installed on the cleaning pipeline 16, and the lower end of the cleaning pipeline 16 is connected to the clean water tank 18 through the cleaning pump 17.

[0028] By controlling the opening and closing of the control valves, the first falling-film evaporator 2 and the second falling-film evaporator 11 can be cleaned when needed.

[0029] The above is only the preferred embodiment of the present application, and any skilled person in the art can modify the technical solutions described above or modify them into equivalent technical solutions. Therefore, any simple modification or equivalent transformation according to the technical solutions of the present application is within the scope of protection required by the present application.

Claims

1. A sodium carbonate salt removal apparatus for use in the distillation of crude propylene glycol, characterized by: The device comprises a propylene glycol light-removing column (1), a first falling film evaporator (2), a buffer tank (3), a feed pump (4), a plate-and-frame filter press (5), a carbonized crude propylene glycol feed line (6), a light-removing line (7), a propylene glycol feed line (8), a reaction rectifying column (9), and a crude propylene glycol feeding pump (10). One side of the reaction rectifying column (9) is connected to a feed line. The bottom of the reaction rectifying column (9) is connected to the top inlet of the first falling film evaporator (2) through the carbonized crude propylene glycol feed line (6) and the crude propylene glycol feeding pump (10). The bottom outlet of the first falling film evaporator (2) is connected to the buffer tank (3) through a pipeline. The top of the buffer tank (3) is connected to the middle-lower side of the propylene glycol light-removing column (1) through the light-removing line (7). The bottom of the buffer tank (3) is connected to the plate-and-frame filter press (5) through a pipeline and the feed pump (4). The outlet of the plate-and-frame filter press (5) is connected to the upper side of the propylene glycol light-removing column (1) through the propylene glycol feed line (8).

2. A sodium carbonate salt removal device for distillation of crude propylene glycol according to claim 1, characterized in that: The bottom of the reaction rectifying column (9) is provided with a reboiler.

3. A sodium carbonate salt removal device for distillation of crude propylene glycol according to claim 1, characterized in that: The first falling film evaporator (2) is provided with a second falling film evaporator (11) in parallel on one side.

4. A sodium carbonate salt removal apparatus for use in the distillation of crude propylene glycol according to claim 3, characterized in that: The carbonized crude propylene glycol feed line (6) connected to the top of the first falling film evaporator (2) is provided with a first control valve (12).

5. A sodium carbonate salt removal apparatus for use in the distillation of crude propylene glycol according to claim 4, characterized in that: The top of the second falling film evaporator (11) is connected to the carbonized crude propylene glycol feed line (6) through a second connecting pipeline and a second control valve (13). The bottom of the second falling film evaporator (11) is connected to the buffer tank (3) through a pipeline.

6. A sodium carbonate salt removal apparatus for use in the distillation of crude propylene glycol according to claim 5, characterized in that: A third control valve (14) is installed on the pipeline at the bottom of the first falling film evaporator (2). A cleaning pipeline (16) is connected to the pipeline in front of the third control valve (14). A fourth control valve (15) is installed on the cleaning pipeline (16). The lower end of the cleaning pipeline (16) is connected to a clean water tank (18) through a cleaning pump (17). The device comprises a propylene glycol light-removing column (1), a first falling film evaporator (2), a buffer tank (3), a feed pump (4), a plate-and-frame filter press (5), a carbonized crude propylene glycol feed line (6), a light-removing line (7), a propylene glycol feed line (8), a reaction rectifying column (9), and a crude propylene glycol feeding pump (10). One side of the reaction rectifying column (9) is connected to a feed line. The bottom of the reaction rectifying column (9) is connected to the top inlet of the first falling film evaporator (2) through the carbonized crude propylene glycol feed line (6) and the crude propylene glycol feeding pump (10). The bottom outlet of the first falling film evaporator (2) is connected to the buffer tank (3) through a pipeline. The top of the buffer tank (3) is connected to the middle-lower side of the propylene glycol light-removing column (1) through the light-removing line (7). The bottom of the buffer tank (3) is connected to the plate-and-frame filter press (5) through a pipeline and the feed pump (4). The outlet of the plate-and-frame filter press (5) is connected to the upper side of the propylene glycol light-removing column (1) through the propylene glycol feed line (8). The bottom of the reaction rectifying column (9) is provided with a reboiler. The first falling film evaporator (2) is provided with a second falling film evaporator (11) in parallel on one side. The carbonized crude propylene glycol feed line (6) connected to the top of the first falling film evaporator (2) is provided with a first control valve (12). The top of the second falling film evaporator (11) is connected to the carbonized crude propylene glycol feed line (6) through a second connecting pipeline and a second control valve (13). The bottom of the second falling film evaporator (11) is connected to the buffer tank (3) through a pipeline. A third control valve (14) is installed on the pipeline at the bottom of the first falling film evaporator (2). A cleaning pipeline (16) is connected to the pipeline in front of the third control valve (14). A fourth control valve (15) is installed on the cleaning pipeline (16). The lower end of the cleaning pipeline (16) is connected to a clean water tank (18) through a cleaning pump (17).

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