Vacuum distillation waste liquid treatment device for XDI synthesis

Abstract

The utility model relates to the technical field of XDI synthesis, in particular to a vacuum distillation waste liquid treatment device for XDI synthesis. Comprising a tank body, the tank body is communicated with the top of a reactor through an inlet pipe, a plurality of arc-shaped partition plates are evenly distributed and fixed in the tank body in the axial direction of the tank body, a gap is formed between one end of each partition plate and the inner wall of the tank body, a baffling channel is formed in the tank body through the partition plates, the partition plates are of hollow structures, and every two adjacent partition plates are internally communicated; a conical liquid-proof cap is fixed to the lower end of the guide cone, the outlet end of the inlet pipe is located in the liquid-proof cap, the interior of the guide cone is communicated with the inlet pipe, the interior of the uppermost partition plate is communicated with the outlet pipe, the upper end of the tank body is fixedly communicated with a vacuum pump, and the vacuum pump is communicated with a gas tank through a pipeline. According to the utility model, organic solvent steam can be left in the tank body after being condensed, and nitrogen enters the gas tank to be stored.

Description

Technical Field

[0001] The utility model relates to the technical field of XDI synthesis, in particular to a vacuum distillation waste liquid treatment device for XDI synthesis. Background Art

[0002] XDI is a kind of ADI (aliphatic isocyanate) containing a benzene ring. It is also called m-xylylene diisocyanate; m-xylylene diisocyanate; m-xylylene diisocyanate; 1,3-bis(isocyanatomethyl)benzene.

[0003] The patent document with application number CN202110202259.4 and titled "Method for preparing high-purity meta-xylylene diisocyanate without phosgene" discloses a method for preparing meta-xylylene diisocyanate without residual chloride ions in the product. It includes the following steps:

[0004] (1) m-Xylylenediamine and dimethyl carbonate are reacted in the presence of a catalyst A. After the reaction is completed, the reaction solution is subjected to solid-liquid separation and filtration to obtain the catalyst A and a filtrate containing M-XDC. The catalyst A is washed with ethanol, dried, and then repeatedly recycled. The filtrate is washed with a dilute hydrochloric acid solution, and then the aqueous phase is separated. The obtained solution phase is concentrated under reduced pressure to remove excess dimethyl carbonate and generated methanol and other solvents to obtain a crude M-XDC product. The crude M-XDC product is recrystallized with anhydrous ethanol, filtered, and dried to obtain methyl m-Xylylenediaminocarbamate.

[0005] (2) adding methyl isophthalate to an organic solvent and performing a decomposition reaction under the action of a catalyst B. During the reaction, the byproduct methanol is vented by nitrogen replacement. After the reaction, the organic solvent is distilled out at a vacuum degree of 1000 to 2000 Pa and a temperature of 100 to 150° C., and the vacuum degree is further reduced to 50 to 500 Pa. The distillation is performed at a temperature of 100 to 150° C. to obtain isophthalate.

[0006] Wherein, in step (2), the reaction is carried out under nitrogen protection, the reaction temperature is 100-300° C., the reaction pressure is 0.1-3 MPa, and the reaction is carried out until the pressure in the reactor no longer increases significantly, and then the reaction is terminated by keeping the temperature for 20-40 minutes. In step (2), the organic solvent is a high-temperature solvent, preferably one or more of dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, o-dichlorobenzene, n-pentadecane, dioctyl sebacate, and diisooctyl sebacate.

[0007] During the vacuum distillation process, organic solvent vapor and nitrogen are mixed and discharged from the reactor. In order to reduce production costs, the organic solvent and nitrogen need to be recovered separately. Utility Model Content

[0008] The technical problem to be solved by the utility model is a vacuum distillation waste liquid treatment device for XDI synthesis which can respectively recover nitrogen and organic solvent during the vacuum distillation process.

[0009] In order to achieve the above purpose, the technical solution provided by the utility model is:

[0010] The vacuum distillation waste liquid treatment device for XDI synthesis comprises a tank body, the lower end of which is fixedly connected with a discharge pipe, the tank body is connected with the top of a reactor through an inlet pipe, the outlet end of the inlet pipe is located in the tank body and faces upward, a plurality of arc-shaped partitions are evenly distributed and fixed in the tank body along its axial direction, a gap is formed between one end of the partition and the inner wall of the tank body, the upper and lower adjacent gaps are staggered left and right, and a plurality of partitions form a baffle channel in the tank body, the partition is a hollow structure, the interiors of two adjacent partitions are connected, and a plurality of baffles are fixed on the opposite end surfaces of the upper and lower adjacent partitions, and the plurality of baffles are parallel and fixed at The baffle on the upper partition is staggered with the baffle fixed on the lower partition, and the multiple baffles form a deflection gap in the gap between the upper and lower adjacent partitions. A hollow guide cone is fixed in the tank body, and the guide cone is connected to the lowest partition through multiple connecting pipes. The tip of the guide cone faces downward, and a conical liquid-proof cap is fixed at the lower end of the guide cone, and the tip of the liquid-proof cap faces upward. The outlet end of the inlet pipe is located in the liquid-proof cap, the interior of the guide cone is connected to the inlet pipe, and the interior of the uppermost partition is connected to the outlet pipe. A vacuum pump is fixedly connected to the upper end of the tank body, and the vacuum pump is connected to the gas tank through a pipeline.

[0011] Specifically, a groove is provided on the lower side of the baffle fixed on the upper end of the partition.

[0012] Specifically, a porous plate is fixed in the tank body between the guide cone and the lowest partition, the connecting pipe passes through the porous plate, and the connecting pipe is fixedly connected to the porous plate.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1. The utility model can keep the vacuum degree of the tank body and the reactor consistent. After the organic solvent vapor and nitrogen enter the tank body, they go up in the tank body. The coolant flows in the inlet pipe, guide cone, connecting pipe, partition, connecting pipe and outlet pipe. The coolant can make the organic solvent vapor condense and remain in the tank body, and the nitrogen enters the gas tank for storage.

[0015] 2. Multiple partitions form a baffle channel in the tank body, and multiple baffles form a baffle gap between two adjacent partitions. The organic solvent vapor can increase the contact area and contact time with the partition during the flow in the baffle channel and the baffle gap, thereby enabling the organic solvent vapor to be completely condensed and separated from nitrogen, thereby improving the separation efficiency of nitrogen and organic solvent vapor.

[0016] 3. After being discharged from the liquid-proof cap, the nitrogen and organic solvent vapor are dispersed by the guide cone. There is flowing coolant in the guide cone, which can improve the cooling efficiency of the organic solvent vapor.

[0017] 4. After the organic solution vapor flowing in the baffle gap between two adjacent partitions is cooled, since the lower end of the baffle fixed on the lower partition is provided with a groove, the liquid organic solvent between the two adjacent partitions can flow out from the groove and flow back to the lower end of the tank body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the utility model.

[0019] Figure 2 Schematic diagram of the internal structure of the tank.

[0020] Figure 3 Diagram showing the position relationship of the baffles on the partition.

[0021] Figure 4 A top view of the guide cone.

[0022] The names of the parts in the attached drawings are:

[0023] 1 Tank

[0024] 2 into the tube

[0025] 3 Vacuum pump

[0026] 4 Row pipe

[0027] 5 Guide cone

[0028] 6 Liquid-proof cap

[0029] 7 Connecting rod

[0030] 8 Inlet pipe

[0031] 9 Outlet

[0032] 10 Connecting pipe

[0033] 11. Multi-well plate

[0034] 12. Partition

[0035] 13 Baffle

[0036] 14 Connecting pipe

[0037] 15 Gas Tank

[0038] 16 grooves. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0040] Example 1: Reference Figure 1-Figure 4 As shown, the vacuum distillation waste liquid treatment device for XDI synthesis includes a tank body 1, and the lower end of the tank body 1 is fixedly connected to a discharge pipe 4. The discharge pipe 4 is installed with a valve.

[0041] The tank body 1 is connected to the top of the reactor through an inlet pipe 2, and the outlet end of the inlet pipe 2 is located in the tank body 1 and faces upward.

[0042] A plurality of arc-shaped partitions 12 are evenly distributed and fixed in the tank body 1 along its axial direction, a gap is formed between one end of the partition 12 and the inner wall of the tank body 1, and the upper and lower adjacent gaps are staggered left and right. The plurality of partitions 12 form a baffle channel in the tank body 1.

[0043] The partition 12 is a hollow structure, and the interiors of two adjacent partitions 12 are connected. Specifically, the interiors of the two adjacent partitions 12 are connected through a connecting pipe 14.

[0044] A plurality of baffles 13 are fixed on opposite end faces of the upper and lower adjacent partitions 12. The plurality of baffles 13 are parallel, and the baffles 13 fixed on the upper partition 12 are staggered with the baffles 13 fixed on the lower partition 12. The plurality of baffles 13 form a deflection gap in the gap between the upper and lower adjacent partitions 12.

[0045] A hollow guide cone 5 is fixed inside the tank body 1. The guide cone 5 is connected to the lowermost partition 12 through a plurality of connecting tubes 10. The tip of the guide cone 5 faces downward. A conical liquid-proof cap 6 is fixed to the lower end of the guide cone 5. Specifically, the guide cone 5 and the liquid-proof cap 6 are fixedly connected through a connecting rod 7. The guide cone 5, the liquid-proof cap 6 and the tank body 1 are concentric. The tip of the liquid-proof cap 6 faces upward. The outlet end of the inlet pipe 2 is located inside the liquid-proof cap 6. The outlet end of the inlet pipe 2 is concentric with the liquid-proof cap 6.

[0046] The interior of the guide cone 5 is communicated with the inlet pipe 8, and the interior of the uppermost partition plate 12 is communicated with the outlet pipe 9. The inlet ends of the inlet pipe 8 and the outlet pipe 9 are both located outside the tank body 1.

[0047] The upper end of the tank body 1 is fixedly connected to a vacuum pump 3 , and the vacuum pump 3 is connected to the gas tank 15 through a pipeline.

[0048] When the material in the reactor needs to be vacuum distilled, the vacuum pump 3 is started to keep the vacuum degree in the reactor consistent with that in the tank body 1. Under the conditions of vacuum degree of 1000-2000 Pa and temperature of 100-150° C., the organic solvent is distilled out, and the vacuum degree is further reduced to 50-500 Pa, and distilled at a temperature of 100-150° C. to obtain m-xylylene diisocyanate.

[0049] During the vacuum distillation process, the cooling liquid is allowed to flow in the inlet pipe 8, the guide cone 5, the connecting pipe 10, the partition 12, the connecting pipe 14 and the outlet pipe 9. The nitrogen and organic solvent vapor in the reactor enter the tank body 1 through the inlet pipe 2, and the nitrogen and organic solvent vapor are discharged from the outlet end of the inlet pipe 2 and enter the liquid-proof cap 6, which can disperse the nitrogen and organic solvent vapor for the first time. The nitrogen and organic solvent vapor discharged from the liquid-proof cap 6 ascend and contact the conical surface of the guide cone 5 and are dispersed for the second time. After the second dispersion, the nitrogen and organic solvent vapor can cool the cooling liquid in the guide cone 5. Part of the organic solvent vapor condenses into liquid and drips into the lower end of the tank body 1. The liquid-proof cap 6 can prevent the liquid organic solvent from dripping into the inlet pipe 2. Part of the organic solvent vapor and nitrogen continue to ascend and flow through the baffle channel and the baffle gap. Since there is flowing coolant inside the partition 12, the organic solvent vapor can increase the contact area and contact time with the partition 12 during the flow in the baffle channel and the baffle gap, so that the organic solvent vapor can be condensed completely and separated from the nitrogen, which can improve the separation efficiency of nitrogen and organic solvent vapor. After being completely condensed, the organic solvent vapor remains in the tank body 1, and the nitrogen enters the gas tank 15 through the vacuum pump 3 for storage.

[0050] Open the valve on the discharge pipe to discharge the liquid organic solvent in the tank.

[0051] Embodiment 2: Based on Embodiment 1, refer to Figure 2 As shown, a groove 16 is formed on the lower side of the baffle 13 fixed to the upper end of the partition 12.

[0052] After the organic solution vapor flowing in the baffle gap between two adjacent partitions 12 is cooled, since the lower end of the baffle 13 fixed on the lower partition 12 is provided with a groove 16, the liquid organic solvent between the two adjacent partitions 12 can flow out from the groove 16 and flow back into the lower end of the tank body 1. This can prevent the liquid organic solvent from being retained between the partitions 12.

[0053] Embodiment 3: Based on Embodiment 1, refer to Figure 1 and Figure 2 As shown, a porous plate 11 is fixed in the tank body 1 between the guide cone 5 and the lowest partition plate 12 , and a connecting pipe 10 passes through the porous plate 11 , and the connecting pipe 10 is fixedly connected to the porous plate 11 .

[0054] By providing the porous plate 11, the porous plate 11 can further disperse the nitrogen and the organic solvent vapor, so that the nitrogen and the organic solvent vapor can be evenly contacted with the bottom partition 12, and the separation rate of nitrogen and the organic solvent can be further improved.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vacuum distillation waste liquid treatment device for XDI synthesis, comprising a tank body (1), the lower end of the tank body (1) is fixedly connected to a discharge pipe (4), the tank body (1) is connected to the top of a reactor through an inlet pipe (2), and is characterized in that: The outlet end of the inlet pipe (2) is located in the tank body (1) and faces upward. A plurality of arc-shaped partitions (12) are evenly distributed and fixed in the tank body (1) along its axial direction. A gap is formed between one end of the partition (12) and the inner wall of the tank body (1). The gaps adjacent to each other are staggered left and right. The plurality of partitions (12) form a baffle channel in the tank body (1). The partition (12) is a hollow structure. The interiors of two adjacent partitions (12) are connected. A plurality of baffles (13) are fixed on opposite end surfaces of two adjacent partitions (12) above and below. The plurality of baffles (13) are parallel. The baffles (13) fixed on the upper partition (12) are staggered with the baffles (13) fixed on the lower partition (12). A baffle (13) forms a baffle gap between two adjacent upper and lower partitions (12). A hollow guide cone (5) is fixed inside the tank body (1). The guide cone (5) is connected to the lowermost partition (12) through a plurality of connecting pipes (10). The tip of the guide cone (5) faces downward. A conical liquid-proof cap (6) is fixed at the lower end of the guide cone (5). The tip of the liquid-proof cap (6) faces upward. The outlet end of the inlet pipe (2) is located inside the liquid-proof cap (6). The interior of the guide cone (5) is connected to the inlet pipe (8). The interior of the uppermost partition (12) is connected to the outlet pipe (9). A vacuum pump (3) is fixedly connected to the upper end of the tank body (1). The vacuum pump (3) is connected to the gas tank (15) through a pipeline.

2. The vacuum distillation waste liquid treatment device for XDI synthesis according to claim 1, characterized in that: A groove (16) is formed on the lower side of the baffle (13) fixed on the upper end of the partition (12).

3. The vacuum distillation waste liquid treatment device for XDI synthesis according to claim 1, characterized in that: A porous plate (11) is fixed in the tank body (1) between the guide cone (5) and the lowest partition plate (12), the connecting pipe (10) passes through the porous plate (11), and the connecting pipe (10) is fixedly connected to the porous plate (11).

4. The vacuum distillation waste liquid treatment device for XDI synthesis according to claim 1, characterized in that: The interiors of the two adjacent partitions (12) are connected via a connecting pipe (14).

5. The vacuum distillation waste liquid treatment device for XDI synthesis according to claim 1, characterized in that: The guide cone (5) and the liquid-proof cap (6) are fixedly connected via a connecting rod (7); the guide cone (5), the liquid-proof cap (6) and the tank body (1) are concentric.

6. The vacuum distillation waste liquid treatment device for XDI synthesis according to claim 1, characterized in that: The inlet ends of the inlet pipe (8) and the outlet pipe (9) are both located outside the tank body (1).

7. The vacuum distillation waste liquid treatment device for XDI synthesis according to claim 1, characterized in that: The outlet end of the inlet pipe (2) is concentric with the liquid-proof cap (6).

8. The vacuum distillation waste liquid treatment device for XDI synthesis according to claim 1, characterized in that: A valve is installed on the row pipe (4).

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