CN214937146U

CN214937146U - Device for improving yield of reaction by-products in polyphenylene sulfide production

Info

Publication number: CN214937146U
Application number: CN202120931389.7U
Authority: CN
Inventors: 霍冰冰; 董栋芳; 吴易静; 钟俊敏
Original assignee: Changzhi Huojia Industry Co ltd
Current assignee: Changzhi Huojia Industry Co ltd
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2021-11-30
Anticipated expiration: 2031-04-30

Abstract

The utility model discloses a device for improving the yield of reaction byproducts in the production of polyphenylene sulfide, belonging to the technical field of polyphenylene sulfide production; the specific scheme is as follows: a concentrated liquid outlet at the bottom of the first rectifying tower is connected with the first rectifying tower through a first pipeline, and a first axial flow circulating pump is arranged on the first pipeline; the concentrated liquid outlet is connected with the first centrifugal machine through a second pipeline, the liquid phase outlet of the first centrifugal machine is connected with the liquid inlet at the top of the second rectifying tower, the bottom discharge port of the second rectifying tower is connected with the second rectifying tower through a third pipeline, and a second axial flow circulating pump is arranged on the third pipeline; a discharge port at the bottom of the second rectifying tower and a discharge port of the wet-based salt of the first centrifugal machine are respectively connected with the evaporator; a discharge port at the bottom of the reaction kettle is connected with a filtering device, and a salt-containing substance discharge port at the upper part of a filter screen is connected with an evaporator; the utility model discloses retrieve link and polyphenylene sulfide production link to NMP and carry out the yield to accessory substance sodium chloride, avoid because the stifled tower that the sodium chloride crystallization caused and to the influence of resultant polyphenylene sulfide.

Description

Device for improving yield of reaction by-products in polyphenylene sulfide production

Technical Field

The utility model belongs to the technical field of the polyphenylene sulfide production, concretely relates to improve device of reaction by-product yield in polyphenylene sulfide production.

Background

Polyphenylene Sulfide (PPS) is a novel polymer material with excellent comprehensive performance. It has high strength, modulus and size stability, and excellent heat resistance, electric insulating property and corrosion resistance.

In the production of polyphenylene sulfide, dichlorobenzene and hydrated sodium sulfide are used as raw materials, an alkali metal grade compound is used as a catalyst, N-methyl-2-pyrrolidone (NMP for short) is used as a solvent, and the target product is prepared by dehydration of sodium sulfide and then pressure polycondensation. The main byproduct of the method is sodium chloride, after the washing of the PPS product and the recovery of NMP by a distillation method are finished, the by-product sodium chloride mainly exists in a resin washing solution and NMP distillation residue, and the existing recovery of the sodium chloride is mainly carried out aiming at the two parts; however, in the process of recovering the NMP, when the mixed solution is dehydrated by intermittent vacuum rectification, because NaCl is not dissolved in the NMP solvent, a large amount of NaCl is crystallized and separated out along with the reduction of water in the tower bottom of the dehydration and rectification tower in the dehydration process, and the separated NaCl salt easily blocks the tower bottom and pipelines on one hand, and on the other hand, the final recovery rate of the sodium chloride byproduct is reduced. And a large amount of byproduct sodium salt generated in the polymerization process can be mixed in the polyphenylene sulfide after the reaction is finished, so that the quality of the polyphenylene sulfide is influenced, and the recovery yield of sodium chloride is also influenced.

SUMMERY OF THE UTILITY MODEL

The utility model overcomes prior art's is not enough, provides a device that improves reaction accessory substance yield in the polyphenylene sulfide production, retrieves link and polyphenylene sulfide production link to NMP respectively and carries out the yield to accessory substance sodium chloride, avoids because the stifled tower that the sodium chloride crystallization caused and to the influence of resultant polyphenylene sulfide.

In order to achieve the above purpose, the present invention is achieved by the following technical solutions.

A device for improving the yield of reaction byproducts in the production of polyphenylene sulfide comprises a reaction kettle, a first rectifying tower, a second rectifying tower, a filtering device, a first centrifugal machine, a second centrifugal machine, an evaporator and a drying device; a concentrated liquid outlet is formed in the bottom of the first rectifying tower and connected with the first rectifying tower through a first pipeline, and a first axial flow circulating pump is arranged on the first pipeline; the concentrated liquid outlet is connected with the first centrifugal machine through a second pipeline, the liquid phase outlet of the first centrifugal machine is connected with the liquid inlet at the top of the second rectifying tower, the bottom discharge port of the second rectifying tower is connected with the second rectifying tower through a third pipeline, and a second axial flow circulating pump is arranged on the third pipeline; a discharge port at the bottom of the second rectifying tower and a discharge port of the wet-based salt of the first centrifugal machine are respectively connected with the evaporator; a discharge port at the bottom of the reaction kettle is connected with a filtering device, a filter screen is arranged in the filtering device, and a salt-containing substance discharge port at the upper part of the filter screen is connected with an evaporator; the bottom discharge hole of the evaporator is connected with a second centrifugal machine, and the second centrifugal machine is connected with a drying device.

Furthermore, the mesh number of the filter screen is 200 meshes and 1000 meshes.

Further, a liquid discharge port of the filtering device is connected with the reaction kettle through a pipeline.

The utility model discloses produced beneficial effect for prior art does:

the utility model discloses retrieve two links to NMP and combine in production and the production with the polyphenylene sulfide, retrieve the accessory substance sodium chloride jointly in these two links, improved the rate of recovery of sodium chloride.

Dehydrating the crude NMP by a first rectifying tower to obtain crude NMP, and rectifying the crude NMP by a second rectifying tower to obtain refined NMP; the axial flow circulating pumps are additionally arranged at the bottoms of the first rectifying tower and the second rectifying tower, forced circulation is carried out at the bottoms of the towers, disturbance of a salt solution in a tower kettle is increased, tower blockage in the towers is avoided, and more salt particles are discharged out of the rectifying towers; in the reaction kettle, the produced polyphenylene sulfide is filtered to remove salt, so that the salt content in the polyphenylene sulfide is reduced, and the salt recovery is improved.

The utility model provides a because the stifled tower that the sodium chloride crystallization caused and to the influence of product polyphenylene sulfide, improved the rate of recovery of accessory substance sodium chloride simultaneously.

Drawings

FIG. 1 is a schematic structural diagram of the apparatus for increasing the yield of reaction by-products.

In the figure, 1 is a reaction kettle; 2 is a first rectifying tower; 3 is a second rectifying tower; 4 is a filtering device; 5 is the first centrifuge, 6 is the second centrifuge, 7 is the evaporimeter, 8 is drying device, 9 is the first pipeline, 10 is first axial flow circulating pump, 11 is the second pipeline, 12 is the third pipeline, 13 is the second axial flow circulating pump, 14 is the filter screen.

Detailed Description

In order to make the technical problem, technical scheme and beneficial effect that the utility model will solve more clearly understand, combine embodiment and attached drawing, it is right to go on further detailed description the utility model discloses. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solution of the present invention is described in detail below with reference to the embodiments and the drawings, but the scope of protection is not limited thereto.

As shown in fig. 1, a device for increasing the yield of reaction byproducts in the production of polyphenylene sulfide, which comprises a reaction kettle 1, a first rectifying tower 2, a second rectifying tower 3, a filtering device 4, a first centrifuge 5, a second centrifuge 6, an evaporator 7 and a drying device 8; a concentrated solution outlet is formed in the bottom of the first rectifying tower 2 and connected with the first rectifying tower 2 through a first pipeline 9, and a first axial circulation pump 10 is arranged on the first pipeline 9; the concentrated liquid outlet is connected with the first centrifuge 5 through a second pipeline 11, the liquid phase outlet of the first centrifuge 5 is connected with the liquid inlet at the top of the second rectifying tower 3, the bottom discharge port of the second rectifying tower 3 is connected with the second rectifying tower 3 through a third pipeline 12, and a second axial flow circulating pump 13 is arranged on the third pipeline 12; a discharge port at the bottom of the second rectifying tower 3 and a discharge port of wet-based salt of the first centrifugal machine 5 are respectively connected with an evaporator 7; the discharge hole at the bottom of the reaction kettle 1 is connected with a filtering device 4, two layers of filter screens 14 are arranged in the filtering device 4, the mesh number of the upper layer of filter screen 14 is 200 meshes, and the mesh number of the lower layer of filter screen 14 is 800 meshes. The salt discharge port at the upper part of the filter screen 14 is connected with the evaporator 7; the liquid discharge port below the filter screen 14 of the filter device 4 is connected with the reaction kettle 1 through a pipeline. The bottom discharge hole of the evaporator 7 is connected with a second centrifuge 6, and the second centrifuge 6 is connected with a drying device 8.

The specific working process is as follows: the mixed solution containing NMP solvent produced in the production process of polyphenylene sulfide enters a first rectifying tower 2 for dehydration to obtain rough NMP, sodium salt is crystallized in the tower continuously along with the process, a part of concentrated solution is pumped into the first rectifying tower 2 again through a first axial flow circulating pump 10 to forcibly circulate at the tower bottom to increase the disturbance of salt solution in the tower kettle, so that the crystallization amount of the salt solution in the tower kettle is reduced, more salt is taken out along with the product and enters a first centrifugal machine 5, wet base salt discharged by the treatment of the first centrifugal machine 5 enters an evaporator 7 for treatment, the liquid part enters a second rectifying tower 3 for further rectification to obtain refined NMP, the refined NMP is discharged from the tower top, the components discharged at the tower bottom enter the evaporator 7 for treatment, meanwhile, an additional axial flow circulating pump is also adopted for the second rectifying tower 3 to forcibly circulate at the tower bottom, the disturbance of the salinity solution in the tower kettle is increased, the formation of small particle crystals in the tower kettle by the salinity solution is avoided, and more salinity is discharged simultaneously. Polyphenylene sulfide produced in the reaction kettle 1 is firstly filtered, salt is filtered out, and then the filtering is circulated for many times to fully filter out the salt, the filtered salt enters an evaporator 7 for treatment, and after the evaporation and crystallization of the evaporator 7, the polyphenylene sulfide is further centrifuged and dried.

The above description is for further details of the present invention with reference to specific preferred embodiments, and it should not be understood that the embodiments of the present invention are limited thereto, and it will be apparent to those skilled in the art that the present invention can be implemented in a plurality of simple deductions or substitutions without departing from the scope of the present invention, and all such alterations and substitutions should be considered as belonging to the present invention, which is defined by the appended claims.

Claims

1. A device for improving the yield of reaction byproducts in the production of polyphenylene sulfide is characterized by comprising a reaction kettle (1), a first rectifying tower (2), a second rectifying tower (3), a filtering device (4), a first centrifugal machine (5), a second centrifugal machine (6), an evaporator (7) and a drying device (8); a concentrated solution outlet is formed in the bottom of the first rectifying tower (2), the concentrated solution outlet is connected with the first rectifying tower (2) through a first pipeline (9), and a first axial circulation pump (10) is arranged on the first pipeline (9); a concentrated liquid outlet is connected with a first centrifugal machine (5) through a second pipeline (11), a liquid phase outlet of the first centrifugal machine (5) is connected with a liquid inlet at the top of a second rectifying tower (3), a discharge hole at the bottom of the second rectifying tower (3) is connected with the second rectifying tower (3) through a third pipeline (12), and a second axial flow circulating pump (13) is arranged on the third pipeline (12); a discharge port at the bottom of the second rectifying tower (3) and a discharge port of wet-based salt of the first centrifugal machine (5) are respectively connected with an evaporator (7); a discharge hole at the bottom of the reaction kettle (1) is connected with a filtering device (4), a filter screen (14) is arranged in the filtering device (4), and a salt-containing substance discharge port at the upper part of the filter screen (14) is connected with an evaporator (7); the bottom discharge hole of the evaporator (7) is connected with a second centrifugal machine (6), and the second centrifugal machine (6) is connected with a drying device (8).

2. The device for increasing the yield of reaction byproducts in the production of polyphenylene sulfide as claimed in claim 1, wherein the mesh number of the filter screen (14) is 200-1000 meshes.

3. The device for improving the yield of the reaction by-products in the production of polyphenylene sulfide as claimed in claim 1, wherein the liquid outlet of the filtering device (4) is connected with the reaction kettle (1) through a pipeline.