Device and method for recycling solid particles of PTA (pure terephthalic acid) oxidation mother liquor

Abstract

The invention discloses a device and method for recycling solid particles of PTA oxidation mother liquor, and relates to the technical field of PTA oxidation mother liquor by-product separation and solid TA particle recycling, the recycling device comprises a feeding unit, a cleaning unit, a circulating pump and a separation unit, the oxidation mother liquor is fed through the feeding unit, and under the action of the circulating pump, the TA particles are separated from the oxidation mother liquor through the separation unit. PTA oxidation mother liquor byproducts, a catalyst and solid TA particles are separated through the separation unit, the separated byproducts and the catalyst enter the distillation tower along with an acetic acid solvent through a third valve, the acetic acid solvent is recycled, and the TA solid particles intercepted by the filtering element return to the oxidation unit for further reaction along with the oxidation mother liquor through a fourth valve. The TA solid is recycled, and the filtering element is quickly recovered after being polluted through the cleaning unit, so that the stable quality of the filtrate is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of separation of byproducts of PTA oxidation mother liquor and recycling of solid TA particles, in particular to a device and a method for recycling solid particles of PTA oxidation mother liquor. Background Art

[0002] In the production process of purified terephthalic acid (PTA), it is necessary to separate part of the oxidation mother liquor to remove the organic by-products and metal impurity ions in it to ensure product quality. Generally, the separation ratio of the oxidation mother liquor is 8-15%. Taking a 600,000 tons / year PTA production unit as an example, the amount of oxidation mother liquor to be separated every day is about 300-400 cubic meters, and the solid content in the oxidation mother liquor is 0.5-2.0%. In addition to a large amount of acetic acid solvent, the oxidation mother liquor also contains terephthalic acid, p-toluic acid, benzoic acid, cobalt, manganese catalyst and other impurities. Among them, terephthalic acid is insoluble in acetic acid and mainly exists in solid form. The mother liquor itself has extremely high added value.

[0003] At present, some PTA production enterprises at home and abroad only recover the acetic acid solvent through distillation, and directly incinerate the oxidation residue. Solid TA materials, Co, Mn catalysts, etc. are treated as PTA waste, which not only increases the unit consumption of raw material PX, but also increases the treatment volume and difficulty of the residue.

[0004] Some manufacturers also use metal sintered filter element filters to filter the oxidation mother liquor. However, this filtration method is a dead-end filtration method, which has problems such as unstable filtrate quality and filtration capacity, complex operation, and the filtered solid particles need to be processed and recycled separately. Summary of the invention

[0005] The object of the present invention is to provide a device and method for recycling solid particles of PTA oxidation mother liquor to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A device for recycling solid particles of PTA oxidation mother liquor, the recycling device comprising a feeding unit, a cleaning unit, a circulation pump and a separation unit, the feeding unit and the circulation pump are connected by a pipeline, the cleaning unit and the feeding unit are connected by a pipeline, the circulation pump and the cleaning unit are connected by a pipeline, and the circulation pump and the separation unit are connected by a pipeline;

[0008] The separation unit comprises a membrane assembly, a No. 3 valve and a No. 4 valve. The membrane assembly is connected to a circulation pump pipeline, the No. 3 valve is connected to a membrane assembly pipeline, and the No. 4 valve is connected to a membrane assembly pipeline.

[0009] The feeding unit delivers a sufficient amount of oxidation mother liquor to the circulation pump, and the oxidation mother liquor reaches the separation unit through the circulation pump and can meet the pressure and flow rate conditions. Through the membrane assembly, the byproducts and catalysts of the oxidation mother liquor are separated with the acetic acid solvent. The separation method adopts cross-flow filtration, and the circulation pump makes the oxidation mother liquor have sufficient surface flow rate to ensure the smooth cross-flow filtration.

[0010] By opening valve No. 3 and closing control valve No. 4, the filtrate separated with the acetic acid solvent can stably enter the distillation tower, and the solvent acetic acid can be recovered through the distillation tower. By closing valve No. 3 and opening valve No. 4, the TA solid particles intercepted by the membrane component can be returned to the production oxidation unit together with the oxidation mother liquor. During the separation process of the separation unit, the cleaning unit is closed to the separation unit. When the membrane component needs to be cleaned, the feed unit, valve No. 3 and valve No. 4 are closed to prevent the cleaning liquid from entering the production system to ensure the quality of the product. The cleaning unit is used to transport a sufficient amount of cleaning liquid to the circulation pump. The cleaning liquid is acid or alkali. The cleaning liquid reaches the separation unit through the circulation pump and can meet the pressure and flow rate conditions, so that the cleaning liquid cleans the membrane component. The used cleaning liquid returns to the cleaning unit through the pipeline, so that the membrane component can be quickly restored after being contaminated, ensuring the separation effect.

[0011] Furthermore, the feed unit includes a No. 1 valve, a mother liquid feed pump and a No. 2 valve, wherein the No. 1 valve is connected to the mother liquid feed pump pipeline, the No. 2 valve is connected to the mother liquid feed pump pipeline, and the No. 2 valve is connected to the cleaning unit pipeline.

[0012] By opening valve No. 1 and adjusting the flow of valve No. 1, the oxidation mother liquor can flow stably into the pipeline and then into the mother liquor feed pump. The mother liquor feed pump provides sufficient oxidation mother liquor for the separation unit. Through valve No. 2, the oxidation mother liquor can flow stably into the separation unit. During cleaning, by closing valve No. 2, the cleaning liquid cannot enter the production system to ensure the quality of the product. The filtrate goes to the distillation tower to recover acetic acid, and the concentrated liquid (retained liquid) goes to the oxidation unit. By controlling the opening of valve No. 2, valve No. 3, and valve No. 4, the oxidation mother liquor feed flow rate is equal to the sum of the filtrate flow rate and the intercepted liquid flow rate, and at the same time, the concentration of the solids retained in the retained liquid meets the requirements of the oxidation process.

[0013] Furthermore, the cleaning unit includes valve No. 5, a cleaning tank, valve No. 6, a cleaning pump, valve No. 7 and valve No. 8. Valve No. 5 is connected to the cleaning tank pipeline, valve No. 6 is connected to the cleaning tank pipeline, the cleaning pump is connected to valve No. 6 pipeline, valve No. 7 is connected to the cleaning pump pipeline, valve No. 7 is connected to the circulation pump pipeline, valve No. 7 is connected to valve No. 2 pipeline, valve No. 8 is connected to the cleaning tank pipeline, and valve No. 8 is connected to the membrane assembly pipeline.

[0014] By opening valve No. 5, the cleaning acid or alkali flows into the cleaning tank through the pipeline. The cleaning tank stores the acid, alkali and other agents used for cleaning. By opening valve No. 6, the cleaning liquid flows through the bottom of the cleaning tank, through valve No. 6 and then flows into the cleaning pump. The cleaning pump ensures that the cleaning liquid has sufficient pressure. By opening valve No. 7, the cleaning liquid flows to the circulation pump. The circulation pump ensures that the cleaning liquid has sufficient flow rate to clean the membrane components. During the cleaning process, by opening valve No. 8, part of the cleaning liquid returns to the cleaning tank to ensure the circulation of the cleaning system. During the mother liquor separation process, by closing valves No. 7 and No. 8, the oxidized mother liquor cannot enter the cleaning system and can only flow out from valves No. 3 and No. 4 to ensure the recovery efficiency.

[0015] Furthermore, the membrane assembly includes a filter element and a membrane shell, the filter element and the membrane shell are fixedly connected, the membrane shell is connected to a circulation pump pipeline, the membrane shell is connected to a No. 3 valve pipeline, the membrane shell is connected to a No. 4 valve pipeline, and the membrane shell is connected to a No. 8 valve pipeline.

[0016] Through the filter element, byproducts and catalysts can be filtered out with the acetic acid solvent. The filter element and the membrane shell are welded to ensure the sealing of the filter element and the membrane shell. The membrane shell and the No. 3 valve pipeline are connected to allow the filtrate to enter the distillation tower through the No. 3 valve for recycling. The membrane shell and the No. 4 valve pipeline are connected to allow the TA solid particles intercepted by the filter element to return to the production oxidation unit with the oxidation mother liquor, realizing the recycling of TA solid particles. The membrane shell and the No. 8 valve pipeline are connected to prevent the oxidation mother liquor from entering the cleaning unit during filtration, realizing the recycling of the cleaning liquid during the cleaning process.

[0017] Furthermore, the filter element is provided with a plurality of filter holes with a pore size of 0.01 to 0.5 μm.

[0018] By setting filter holes of 0.01 to 0.5 μm in the filter element, TA solid particles can be effectively retained in cross-flow filtration. Through the circulation pump, the oxidation mother liquor forms turbulence on the surface of the filter element, thereby taking away the solids attached to the filter element, effectively preventing the filter holes from being blocked, thereby ensuring the accuracy of filtration.

[0019] Furthermore, the filter element is made of an inorganic material, and the inorganic material is a metal oxide.

[0020] By using inorganic materials for the filter elements, such as zirconium dioxide, titanium dioxide, stainless steel, alloys, nickel alloys and other metal oxides, it is possible to effectively prevent the corrosion of PTA oxidation mother liquor and cleaning liquid acids and alkali agents, ensuring the long-term and stable use of the filter elements.

[0021] The method for recycling solid particles of PTA oxidation mother liquor comprises the following steps:

[0022] S1: The oxidation mother liquor enters the mother liquor feed pump through valve No. 1, and a sufficient amount of oxidation mother liquor is transported by the mother liquor feed pump and flows to the circulation pump through valve No. 2;

[0023] S2: The oxidation mother liquor enters the membrane module through the circulation pump, and the filter element separates the TA solid particles, by-products and catalysts through cross-flow filtration. The by-products and catalysts enter the distillation tower with the acetic acid solvent through the No. 3 valve to realize the recovery of the acetic acid solvent;

[0024] S3: TA and other solid particles intercepted by the filter element are returned to the oxidation unit with the oxidation mother liquor through the No. 4 valve for further reaction, so as to realize the reuse of TA solids;

[0025] S4: The cleaning liquid enters the cleaning tank through valve No. 5, flows to the cleaning pump through valve No. 6 at the bottom of the cleaning tank, and flows to the circulation pump through valve No. 7 through the cleaning pump;

[0026] S5: Provide sufficient flow rate for the cleaning liquid through the circulation pump, and clean the surface of the filter element with the cleaning liquid.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. By setting the pore size of the filter element to 0.01-0.5 μm, TA solid particles can be effectively retained in cross-flow filtration. Through the circulation pump, the oxidation mother liquor forms turbulence on the surface of the filter element, thereby taking away the solids attached to the filter element, effectively preventing the clogging of the filter pores, achieving high-precision filtration, and effectively separating TA solid particles, by-products and catalysts.

[0029] 2. Solid particles such as TA intercepted by the filter element are directly returned to the production system with the mother liquor, which increases the product yield, ensures product quality and reduces the amount of residue and processing costs.

[0030] 3. Continuous feeding is carried out through the mother liquor feed pump, and the circulation pump provides sufficient flow rate for the oxidation mother liquor to achieve continuous feeding and continuous separation and filtration to ensure the continuity of production.

[0031] 4. The cross-flow filtration and cleaning unit can quickly recover the contaminated filter element, ensuring the stable quality of the filtrate and reducing the difficulty of solvent and catalyst recovery.

[0032] 5. By using valves at various nodes to ensure the stability of the flow, and by using controllable devices such as feed pumps, circulation pumps and cleaning pumps, the equipment can be fully self-controlled, reducing labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of a device and method for recycling solid particles of PTA oxidation mother liquor according to the present invention;

[0034] In the figure: 1, feed unit; 11, valve No. 1; 12, mother liquor feed pump; 13, valve No. 2; 2, cleaning unit; 21, valve No. 5; 22, cleaning tank; 23, valve No. 6; 24, cleaning pump; 25, valve No. 7; 26, valve No. 8; 3, circulation pump; 4, separation unit; 41, membrane assembly; 411, filter element; 412, membrane shell; 42, valve No. 3; 43, valve No. 4; DETAILED DESCRIPTION

[0035] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0036] Example: Figure 1 As shown, the present invention provides a device and method technical solution for recycling solid particles of PTA oxidation mother liquor, a device for recycling solid particles of PTA oxidation mother liquor, the recycling device comprises a feeding unit 1, a cleaning unit 2, a circulating pump 3 and a separation unit 4, the feeding unit 1 is connected to the circulating pump 3 through a pipeline, the cleaning unit 2 is connected to the feeding unit 1 through a pipeline, the circulating pump 3 is connected to the cleaning unit 2 through a pipeline, and the circulating pump 3 is connected to the separation unit 4 through a pipeline;

[0037] The separation unit 4 includes a membrane assembly 41, a No. 3 valve 42 and a No. 4 valve 43. The membrane assembly 41 is connected to the circulation pump 3 by a pipeline, the No. 3 valve 42 is connected to the membrane assembly 41 by a pipeline, and the No. 4 valve 43 is connected to the membrane assembly 41 by a pipeline.

[0038] A sufficient amount of oxidation mother liquor is delivered to the circulation pump 3 through the feed unit 1. The oxidation mother liquor reaches the separation unit 4 through the circulation pump 3 and can meet the pressure and flow rate conditions. Through the membrane component 41, the byproducts and catalysts of the oxidation mother liquor are separated with the acetic acid solvent. The separation method adopts cross-flow filtration. Through the circulation pump 3, the oxidation mother liquor has sufficient surface flow rate to ensure the smooth cross-flow filtration. By opening the No. 3 valve 42 and closing the No. 4 valve 43, the filtrate separated with the acetic acid solvent can stably enter the distillation tower, and the solvent acetic acid is recovered through the distillation tower. The concentrated liquid returns to the oxidation section with a stable solid concentration and flow rate. By closing the No. 3 valve 42 and opening the No. 4 valve 43, the TA solid particles intercepted by the membrane component 41 are returned to the production oxidation unit together with the oxidation mother liquor.

[0039] During the separation process of the separation unit 4, the cleaning unit 2 is closed to the separation unit 4. When the membrane assembly 41 needs to be cleaned, the feed unit 1, valve No. 3 42 and valve No. 4 43 are closed to prevent the cleaning liquid from entering the production system to ensure the quality of the product. The cleaning unit 2 delivers a sufficient amount of cleaning liquid to the circulation pump 3. The cleaning liquid is acid or alkali. The cleaning liquid reaches the separation unit 4 through the circulation pump 3 and can meet the pressure and flow rate conditions, so that the cleaning liquid cleans the membrane assembly 41. The used cleaning liquid returns to the cleaning unit 2 through the pipeline, so that the membrane assembly 41 can be quickly restored after being contaminated, ensuring the separation effect.

[0040] like Figure 1 As shown, the feed unit 1 includes a valve No. 11, a mother liquid feed pump 12 and a valve No. 2 13, the valve No. 11 is connected to the mother liquid feed pump 12 by a pipeline, the valve No. 2 13 is connected to the mother liquid feed pump 12 by a pipeline, and the valve No. 2 13 is connected to the cleaning unit 2 by a pipeline.

[0041] By opening valve No. 11 and adjusting the flow of valve No. 11, the oxidized mother liquor can flow stably into the pipeline and then into the mother liquor feed pump 12. The mother liquor feed pump 12 provides sufficient oxidized mother liquor for the separation unit 4. Through valve No. 2 13, the oxidized mother liquor can flow stably into the separation unit 4. During cleaning, by closing valve No. 2 13, the cleaning liquid cannot enter the production system to ensure the quality of the product. By controlling the opening of valve No. 2, valve No. 3, and valve No. 4, as well as the pressure of the feed pump, the filtrate flow rate is stable and the concentrated liquid discharge flow rate is stable.

[0042] like Figure 1 As shown, the cleaning unit 2 includes valve No. 5 21, a cleaning tank 22, valve No. 6 23, a cleaning pump 24, valve No. 7 25 and valve No. 8 26. Valve No. 5 21 is connected to the cleaning tank 22 by a pipeline, valve No. 6 23 is connected to the cleaning tank 22 by a pipeline, the cleaning pump 24 is connected to valve No. 6 23 by a pipeline, valve No. 7 25 is connected to the cleaning pump 24 by a pipeline, valve No. 7 25 is connected to the circulation pump 3 by a pipeline, valve No. 7 25 is connected to valve No. 2 13 by a pipeline, valve No. 8 26 is connected to the cleaning tank 22 by a pipeline, and valve No. 8 26 is connected to the membrane assembly 41 by a pipeline.

[0043] By opening valve No. 5 21, the cleaning liquid acid or alkali flows into the cleaning tank 22 through the pipeline. The cleaning tank 22 stores the cleaning acid, alkali and other reagents. By opening valve No. 6 23, the cleaning liquid flows through the bottom of the cleaning tank 22, through valve No. 6 23 and then flows into the cleaning pump 24. The cleaning pump 24 ensures that the cleaning liquid has sufficient pressure. By opening valve No. 7 25, the cleaning liquid flows to the circulation pump 3. The circulation pump 3 ensures that the cleaning liquid has sufficient flow rate to clean the membrane component 41. During the cleaning process, by opening valve No. 8 26, part of the cleaning liquid returns to the cleaning tank 22 to ensure the circulation of the cleaning system. During the mother liquor separation process, by closing valve No. 7 25 and valve No. 8 26, the oxidized mother liquor cannot enter the cleaning system and can only flow out from valve No. 3 42 and valve No. 4 43 to ensure the recovery efficiency.

[0044] like Figure 1 As shown, the membrane assembly 41 includes a filter element 411 and a membrane shell 412, the filter element 411 and the membrane shell 412 are fixedly connected, the membrane shell 412 and the circulation pump 3 are connected by a pipeline, the membrane shell 412 and the valve No. 3 42 are connected by a pipeline, the membrane shell 412 and the valve No. 4 43 are connected by a pipeline, and the membrane shell 412 and the valve No. 8 26 are connected by a pipeline.

[0045] Through the filter element 411, the by-products and catalysts can be filtered out along with the acetic acid solvent. The filter element 411 and the membrane shell 412 are welded to ensure the sealing of the filter element 411 and the membrane shell 412. The membrane shell 412 and the No. 3 valve 42 are connected by a pipeline so that the filtrate enters the distillation tower through the No. 3 valve 42 for recycling. The membrane shell 412 and the No. 4 valve 43 are connected by a pipeline so that the TA solid particles retained by the filter element 411 are returned to the production oxidation unit along with the oxidation mother liquor, thereby realizing the recycling of the TA solid particles. The membrane shell 412 and the No. 8 valve 26 are connected by a pipeline so that the oxidation mother liquor cannot enter the cleaning unit 2 during filtration, thereby realizing the recycling of the cleaning liquid during the cleaning process.

[0046] like Figure 1 As shown, the filter element 411 is provided with a plurality of filter holes with a pore size of 0.01 to 0.5 μm.

[0047] By setting filter holes of 0.01 to 0.5 μm in the filter element 411, TA solid particles can be effectively retained in cross-flow filtration. Through the circulation pump 3, the oxidation mother liquor forms turbulence on the surface of the filter element 411, thereby taking away the solids attached to the filter element 411, effectively preventing the filter holes from being blocked, thereby ensuring the accuracy of filtration.

[0048] like Figure 1 As shown, the filter element 411 is made of an inorganic material, and the inorganic material is a metal oxide.

[0049] By using inorganic materials for the filter element 411, such as metal oxides such as zirconium dioxide, titanium dioxide, stainless steel, alloy, nickel alloy, etc., it is possible to effectively prevent corrosion from PTA oxidation mother liquor and cleaning liquid acid and alkali agents, thereby ensuring long-term and stable use of the filter element 411.

[0050] The method for recycling solid particles of PTA oxidation mother liquor comprises the following steps:

[0051] S1: The oxidation mother liquor enters the mother liquor feed pump 12 through the No. 1 valve 11, and a sufficient amount of oxidation mother liquor is transported by the mother liquor feed pump 12, and flows to the circulation pump 3 through the No. 2 valve 13;

[0052] S2: The oxidation mother liquor enters the membrane assembly 41 through the circulation pump 3, and the TA solid particles, by-products and catalysts are separated by the filter element 411 through cross-flow filtration. The by-products and catalysts enter the distillation tower with the acetic acid solvent through the No. 3 valve 42 to realize the recovery of the acetic acid solvent;

[0053] S3: The TA solid particles intercepted by the filter element 411 are returned to the oxidation unit along with the oxidation mother liquor through the fourth valve 43 for further reaction, thereby realizing the reuse of the TA solids;

[0054] S4: The cleaning liquid enters the cleaning tank 22 through the No. 5 valve 21, flows through the bottom of the cleaning tank 22 through the No. 6 valve 23 to the cleaning pump 24, and flows through the cleaning pump 24 through the No. 7 valve 25 to the circulation pump 3;

[0055] S5: The circulation pump 3 provides a sufficient flow rate for the cleaning liquid, and the cleaning liquid is used to clean the surface of the filter element 411.

[0056] Working principle: The oxidation mother liquor enters the mother liquor feed pump 12 through the No. 1 valve 11, and a sufficient amount of oxidation mother liquor is transported through the No. 2 valve 13 to the circulation pump 3 through the mother liquor feed pump 12. The circulation pump 3 provides a sufficient flow rate for the oxidation mother liquor to enter the membrane component 41. Under certain pressure and flow rate conditions, the filter element 411 separates the TA solid particles, by-products, catalysts and solvents. The separated by-products and catalysts flow out from the filtrate side of the membrane with the acetic acid solvent, and enter the rear distillation tower after passing through the No. 3 valve 42 to recover the solvent acetic acid. The No. 3 valve 42 can adjust the flow rate of the filtrate to ensure that the system has a sufficient and stable amount of filtrate separated from the system. The TA solid particles intercepted by the membrane are returned to the oxidation unit in production together with the oxidation mother liquor through the No. 4 valve 43 for further treatment. reaction, and completely realize the reuse of TA. During the separation process, valve No. 7 25 and valve No. 8 26 are in a completely closed state to prevent leakage of the oxidized mother liquor. The cleaning liquid acid or alkali enters the cleaning tank 22 through valve No. 5 21, and then enters the cleaning pump 24 from the bottom of the cleaning tank 22 through valve No. 6 23. The cleaning pump 24 provides sufficient pressure for the cleaning liquid and then sends it to the circulation pump 3 through valve No. 7 25. The circulation pump 3 provides sufficient cleaning flow rate for cleaning the surface of the filter element 411. During the cleaning process, part of the cleaning liquid returns to the cleaning tank 22 through valve No. 8 26 to ensure that the cleaning liquid circulates in the entire cleaning system. During the separation process, valve No. 2 13, valve No. 3 42 and valve No. 4 43 are in a completely closed state to prevent the cleaning liquid from entering the production system.

[0057] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for recycling solid particles of PTA oxidation mother liquor, characterized by: The recycling device comprises a feeding unit (1), a cleaning unit (2), a circulation pump (3) and a separation unit (4); the feeding unit (1) and the circulation pump (3) are connected by a pipeline, the cleaning unit (2) and the feeding unit (1) are connected by a pipeline, the circulation pump (3) and the cleaning unit (2) are connected by a pipeline, and the circulation pump (3) and the separation unit (4) are connected by a pipeline; The separation unit (4) comprises a membrane assembly (41), a third control valve (42) and a fourth control valve (43); the membrane assembly (41) is connected to a circulation pump (3) via a pipeline, the third control valve (42) is connected to the membrane assembly (41) via a pipeline, and the fourth control valve (43) is connected to the membrane assembly (41) via a pipeline.

2. The device for recycling solid particles of PTA oxidation mother liquor according to claim 1, characterized in that: The feeding unit (1) comprises a first control valve (11), a mother liquid feeding pump (12) and a second control valve (13); the first control valve (11) and the mother liquid feeding pump (12) are connected by a pipeline; the second control valve (13) and the mother liquid feeding pump (12) are connected by a pipeline; and the second control valve (13) and the cleaning unit (2) are connected by a pipeline.

3. The device for recycling solid particles of PTA oxidation mother liquor according to claim 2, characterized in that: The cleaning unit (2) comprises a No. 5 control valve (21), a cleaning tank (22), a No. 6 control valve (23), a cleaning pump (24), a No. 7 control valve (25) and a No. 8 control valve (26); the No. 5 control valve (21) is connected to the cleaning tank (22) by a pipeline, the No. 6 control valve (23) is connected to the cleaning tank (22) by a pipeline, the cleaning pump (24) is connected to the No. 6 control valve (23) by a pipeline, the No. 7 control valve (25) is connected to the cleaning pump (24) by a pipeline, the No. 7 control valve (25) is connected to the circulation pump (3) by a pipeline, the No. 7 control valve (25) is connected to the No. 2 control valve (13) by a pipeline, the No. 8 control valve (26) is connected to the cleaning tank (22) by a pipeline, and the No. 8 control valve (26) is connected to the membrane assembly (41) by a pipeline.

4. The device for recycling solid particles of PTA oxidation mother liquor according to claim 3 is characterized in that: The membrane assembly (41) includes a filter element (411) and a membrane shell (412), wherein the filter element (411) and the membrane shell (412) are fixedly connected, the membrane shell (412) and the circulation pump (3) are connected by a pipeline, the membrane shell (412) and the third control valve (42) are connected by a pipeline, the membrane shell (412) and the fourth control valve (43) are connected by a pipeline, and the membrane shell (412) and the eighth control valve (26) are connected by a pipeline.

5. The device for recycling solid particles of PTA oxidation mother liquor according to claim 4, characterized in that: The filter element (411) is provided with a plurality of filter holes with a pore size of 0.01 to 0.5 μm.

6. The device for recycling solid particles of PTA oxidation mother liquor according to claim 5, characterized in that: The filter element (411) is made of an inorganic material, and the inorganic material is a metal oxide.

7. The method for recycling solid particles of PTA oxidation mother liquor according to claim 6, characterized in that: The method for recycling comprises the following steps: S1: Feeding unit (1) feeds oxidation mother liquor; S2: separation unit (4) recovers the solvent acetic acid; S3: separation unit (4) TA reuse; S4: the cleaning liquid enters the cleaning unit (2); S5: The separation unit (4) is cleaned with a cleaning liquid.

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