Gradient filtration solvent recovery device

Abstract

The utility model discloses a gradient filtration solvent recovery device which comprises a solid-liquid separation unit, a filtration and adsorption unit, a distillation unit, a rectification unit and an intermediate storage unit, wherein the solid-liquid separation unit is connected with the filtration and adsorption unit; the filtration and adsorption unit is connected with the distillation unit; the distillation unit is respectively connected with the rectification unit and the waste liquid treatment system; the rectification unit is connected with a finished product storage tank; the middle storage unit comprises a middle storage tank; the middle storage tank is connected with the distillation unit and the rectification unit; the device is ingenious in structural design and convenient to maintain and replace, the purity of a solvent is improved through multi-stage filtration, and effective recycling and cost reduction can be realized through combination of distillation and rectification and high purification.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, and more specifically to a gradient filtration solvent recovery device. Background Technology

[0002] With the increasing market demand for bis(fluorosulfonyl)imide, a novel electrolyte for lithium-ion batteries, in recent years, the production process of its raw material, bis(fluorosulfonyl)imide, has become increasingly important. The most valuable production method currently is to further produce bis(fluorosulfonyl)imide through fluorine-chlorine exchange of bis(chlorosulfonyl)imide. Bis(chlorosulfonyl)imide is currently the intermediate in the mainstream process for lithium bis(fluorosulfonyl)imide.

[0003] The production of bischlorosulfonylimide typically involves a condensation reaction between aminosulfonic acid and chlorosulfonic acid in the presence of thionyl chloride. In chemical reactions within chemical projects, most reactions involve dissolving reactants in a solvent for homogeneous reactions. After the reaction, the product is a liquid phase and must be separated from the solvent. If the product is a solid, solid-liquid separation is usually achieved through methods such as pressure filtration and centrifugation. The separated mother liquor is recycled after a certain number of batches. However, as impurities accumulate in the mother liquor, it can negatively impact product quality. Utility Model Content

[0004] The purpose of this invention is to provide a gradient filtration solvent recovery device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model employs the following technical means:

[0006] A gradient filtration solvent recovery device includes:

[0007] The solid-liquid separation unit is used for coarse filtration to separate solid products and treat the mother liquor with accumulated impurities, and is connected to the filtration and adsorption unit.

[0008] The filtration and adsorption unit is used to retain, adsorb, and remove impurities from the mother liquor, and is connected to the distillation unit; the distillation unit is used to purify the solvent, and is connected to the rectification unit and the waste liquid treatment system respectively.

[0009] The distillation unit, used to separate and purify the solvent, is connected to the finished product storage tank;

[0010] The intermediate storage unit includes an intermediate storage tank, which is connected to the distillation unit and the rectification unit.

[0011] Furthermore, the solid-liquid separation unit includes a coarse filtration separation component connected to the outlet of the reactor. The filtrate outlet of the coarse filtration separation component is connected to a mother liquor buffer tank via a pipeline. The bottom of the mother liquor buffer tank is connected to the reactor via a circulation pump, and the upper part of the mother liquor buffer tank is connected to a filtration and adsorption unit via a pipeline.

[0012] Furthermore, the filtration and adsorption unit includes a coarse filtration component, an adsorption component, and a fine filtration component connected in sequence;

[0013] The coarse filter component includes a coarse filter housing, a frustum-shaped flow guide is installed inside the coarse filter housing, a first filter plate is detachably installed on the flow guide, a cylindrical mounting sleeve is connected to the lower part of the flow guide, an annular base is provided on the lower inner wall of the mounting sleeve, and a filter membrane tube is movably installed inside the mounting sleeve.

[0014] The adsorption component includes an adsorption shell, inside which an activated carbon adsorption assembly is installed. The activated carbon adsorption assembly includes a placement frame detachably disposed inside the adsorption shell, and the placement frame contains a packing material with a specific surface area ≥1200 m². 2 / g of columnar coconut shell activated carbon, wherein the activated carbon adsorption component is provided with filter screens at both the upper and lower ends, and the pore size of the filter screens is 0.05-0.1mm;

[0015] The fine filtration component includes a fine filtration housing, inside which a molecular sieve assembly is installed. The molecular sieve assembly has several sets of evenly distributed and vertically arranged heating holes. Inside the fine filtration housing, an electric heating component is provided above the molecular sieve assembly. Each electric heating rod in the electric heating component is inserted into each of the heating holes, and the depth of each electric heating rod inserted into the molecular sieve assembly is ≥2 / 3.

[0016] Furthermore, the distillation unit includes a first distillation column connected to the filtration and adsorption unit. The top of the first distillation column is connected to a first condenser. The first condenser is connected to an intermediate storage tank and the first distillation column via a reflux pump. The bottom of the first distillation column is connected to a waste liquid treatment system.

[0017] Furthermore, the distillation unit includes a first distillation column, the feed inlet of which is connected to the outlet of an intermediate storage tank, a second condenser connected to the top of the first distillation column, the second condenser being connected to a finished product storage tank via a reflux ratio controller, the bottom of the first distillation column being connected to the intermediate storage tank, and the finished product storage tank being connected to the feed inlet of a reaction vessel via a metering pump.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The various functional units of this utility model have clearly defined roles. The solid-liquid separation, filtration and adsorption, distillation, rectification and intermediate storage units each undertake specific tasks, which facilitates daily maintenance, repair and management by operators. The device improves solvent purity through multi-stage filtration, and achieves high purification through a combination of distillation and rectification, enabling effective recycling and cost reduction. Attached image description:

[0020] Figure 1 This is a schematic diagram of a gradient filtration solvent recovery device provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of a gradient filtration solvent recovery device provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the coarse filter component of the product in an embodiment of this utility model;

[0023] Figure 4 This is a top view schematic diagram of the coarse filter component of the product in this embodiment of the utility model;

[0024] Figure 5 The embodiments of this utility model are as follows Figure 4 Schematic diagram of the cross-sectional structure of section AA;

[0025] Figure 6 This is a schematic diagram of the coarse filter component of the product in an embodiment of this utility model;

[0026] Figure 7 This is a schematic diagram of the coarse filter component of the product in an embodiment of this utility model;

[0027] Figure 8 This is a schematic diagram of the structure of the product adsorption component in an embodiment of this utility model;

[0028] Figure 9 This is a cross-sectional schematic diagram of the structure of the fine filtration component of the product in an embodiment of this utility model;

[0029] Figure 10 This is a schematic diagram of the structure of the fine filtration component in the embodiment of this utility model. Detailed implementation method:

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. The following embodiments and drawings are only used to more clearly illustrate the technical solution of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application. The drawings only schematically show the parts related to the technical solution of this application, and do not represent their actual structure as a product.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0035] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0036] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0037] In this embodiment, a gradient filtration solvent recovery device includes:

[0038] The solid-liquid separation unit 100 is used for coarse filtration to separate solid products and treat the mother liquor with accumulated impurities, and is connected to the filtration and adsorption unit 200.

[0039] The filtration and adsorption unit 200 is used to retain, adsorb and remove impurities from the mother liquor, and is connected to the distillation unit 300.

[0040] Distillation unit 300 is used to purify solvent, and distillation unit 300 is connected to rectification unit 400 and waste liquid treatment system 330 respectively;

[0041] Distillation unit 400 is used to separate and purify solvents and is connected to finished product storage tank 600;

[0042] The intermediate storage unit 500 includes an intermediate storage tank 510, which is connected to the distillation unit 300 and the rectification unit 400.

[0043] This invention utilizes a multi-stage process involving a solid-liquid separation unit 100, a filtration and adsorption unit 200, a distillation unit 300, and a rectification unit 400 to progressively remove solid impurities and various soluble impurities from the mother liquor. The solid-liquid separation unit 100 first performs preliminary solid-liquid separation, removing solid products and reducing the burden on subsequent processing. The filtration and adsorption unit 200 further removes fine impurities and adsorbs harmful substances. The distillation unit 300 purifies the solvent through distillation, and the rectification unit 400 performs even finer separation, resulting in a high-purity recovered solvent that meets the requirements of subsequent production. Furthermore, the distillation unit... The distillation unit 300 is connected to the waste liquid treatment system 330 to specifically treat the waste liquid that is difficult to reuse after distillation, avoiding the random discharge of harmful substances, meeting environmental protection requirements, and reducing environmental pollution. The intermediate storage tank 510 of the intermediate storage unit 500 is connected to the distillation unit 300 and the rectification unit 400, playing a buffering and regulating role. During the distillation and rectification process, materials can be flexibly stored and allocated according to the processing speed and production needs of each unit, ensuring the stability and continuity of the entire recovery device and avoiding production stagnation or efficiency reduction caused by the mismatch of processing speeds between the front and rear units.

[0044] Furthermore, the distillation unit 400 is connected to the finished product storage tank 600, allowing the recovered solvent in the tank to be reused, thus achieving solvent recycling. This reduces the amount of fresh solvent needed, lowers production costs, and improves resource utilization, resulting in significant economic and resource-saving benefits.

[0045] The functional units of the device disclosed in this utility model have clear division of labor. The solid-liquid separation, filtration and adsorption, distillation, rectification and intermediate storage units each undertake specific tasks, which facilitates the daily maintenance, inspection and management of operators. If a unit fails, it is easier to troubleshoot and repair, reducing equipment downtime.

[0046] In one or more possible embodiments of this utility model, the solid-liquid separation unit 100 includes a coarse filtration separation component 110 connected to the outlet of the reaction vessel. The filtrate outlet of the coarse filtration separation component 110 is connected to a mother liquor buffer tank 120 via a pipe. The bottom of the mother liquor buffer tank 120 is connected to the reaction vessel via a circulation pump. The upper part of the mother liquor buffer tank 120 is connected to a filtration and adsorption unit 200 via a pipe. Specifically, the coarse filtration separation component 110 can be a centrifuge or a filter press to achieve coarse filtration separation of solid products. The bottom of the mother liquor buffer tank 120 is connected to the reaction vessel via a circulation pump, which can return the mother liquor to the reaction vessel to participate in the reaction again. The mother liquor buffer tank 120 is connected to the filtration and adsorption unit 200 to treat the mother liquor after the accumulation of impurities.

[0047] In one or more possible embodiments of the present invention, the filtration and adsorption unit 200 includes a coarse filtration component 210, an adsorption component 220, and a fine filtration component 230 connected in sequence.

[0048] The coarse filtration component 210 includes a coarse filter housing 211. A frustum-shaped flow guide 212 is installed inside the coarse filter housing 211. A first filter plate 213 is detachably mounted on the flow guide 212. A cylindrical mounting sleeve 214 is connected to the lower part of the flow guide 212. An annular base 215 is provided on the lower inner wall of the mounting sleeve 214. A filter membrane tube 216 is movably mounted inside the mounting sleeve 214. In this embodiment, the coarse filtration component 210 is used to achieve preliminary interception of suspended particles in the solvent, thereby reducing the load on subsequent modules. As shown in the accompanying drawings, the structure in the drawings is for illustrative purposes only, and only a portion of the structure of the coarse filter housing 211, such as the inlet, is disclosed. The discharge port and rinsing port are not disclosed. The frustum-shaped flow guide 212 and the detachable first filter plate 213 in the coarse filter component 210 are conducive to guiding the flow of mother liquor and facilitate the preliminary filtration of impurities with larger diameters. The aperture of the first filter plate 213 can be set according to specific needs. Moreover, the first filter plate 213 is easy to disassemble and replace, which can reduce maintenance costs. At the same time, the filter membrane tube 216 is movably installed in the installation sleeve 214, which also facilitates its inspection, cleaning or replacement. The filter membrane tube 216 has a membrane shell made of stainless steel. The membrane shell contains an alumina-based ceramic membrane tube with multiple sets of holes and a pore size of 5-10μm, which realizes the preliminary interception of suspended particles in the solvent.

[0049] The adsorption component 220 includes an adsorption shell 221, inside which an activated carbon adsorption assembly 222 is installed. The activated carbon adsorption assembly 222 includes a placement frame detachably disposed inside the adsorption shell 221, and the placement frame contains a filling material with a specific surface area ≥1200m². 2 / g of columnar coconut shell activated carbon; the activated carbon adsorption component 222 is provided with filter screens 223 at both the upper and lower ends, and the pore size of the filter screens 223 is 0.05-0.1mm; in this embodiment, the adsorption component 220 adopts a specific surface area ≥1200m². 2 / g columnar coconut shell activated carbon has a strong adsorption capacity, which can effectively adsorb pigments, colloids and some volatile substances in the mother liquor, further purifying the mother liquor. Moreover, the filter screens 223 set at the upper and lower ends of the activated carbon adsorption component 222 can prevent activated carbon particles from entering the subsequent process, ensuring the filtration effect while avoiding clogging or contamination of the equipment, thereby improving the quality of the recovered solvent. To further improve the automation level of this utility model, a differential pressure sensor can be integrated on the side wall of the adsorption shell 221, in conjunction with other signal acquisition components and related components such as pneumatic ball valves installed on the device, to realize automatic adjustment of fluid flow. The specific technical solution will not be described in this utility model.

[0050] The fine filtration component 230 includes a fine filtration housing 231, inside which a molecular sieve assembly 232 is installed. The molecular sieve assembly 232 has several sets of evenly distributed and vertically arranged heating holes 233. An electric heating component 234 is disposed inside the fine filtration housing 231 above the molecular sieve assembly 232. Each electric heating rod 235 in the electric heating component 234 is inserted into one of the heating holes 233, and the depth of insertion of each electric heating rod 235 into the molecular sieve assembly 232 is greater than 2 / 3 of the height of the molecular sieve assembly 232. In this invention, the molecular sieve assembly 232 in the fine filtration component 230 can... The mother liquor is deeply filtered to remove impurities with smaller particle sizes, and trace amounts of water and small molecule impurities in the solvent are thoroughly removed. The electric heating component 234 is designed to work in conjunction with the molecular sieve assembly 232. The electric heating rod 235 is inserted into the heating hole 233 to a depth of more than 2 / 3, which can uniformly heat the molecular sieve assembly 232, maintain its good activity and adsorption performance, effectively remove water and other residual impurities from the mother liquor, and ensure the high purity of the final recovered solvent. In addition, several temperature sensors can be set in the middle and bottom of the molecular sieve assembly 232, and gradient temperature control can be achieved through PID algorithm to further improve the performance of the molecular sieve assembly 232.

[0051] A gradient filtration system is formed by sequentially connecting a coarse filtration component 210, an adsorption component 220, and a fine filtration component 230. The coarse filtration component 210 intercepts larger particulate impurities, the adsorption component 220 adsorbs small molecule impurities and organic matter, and the fine filtration component 230 further removes even finer impurities. Through this progressively finer filtration method, the purity of the mother liquor can be effectively improved, providing a purer raw material for subsequent solvent recovery.

[0052] In one or more possible embodiments of this utility model, the distillation unit 300 includes a first distillation column 310 connected to the filtration and adsorption unit 200. The top of the first distillation column 310 is connected to a first condenser 320. The first condenser 320 is connected to the intermediate storage tank 510 and the first distillation column 310 respectively via a reflux pump. The bottom of the first distillation column 310 is connected to a waste liquid treatment system 330. Specifically, the first distillation column 310 is provided with multiple layers of packing. After the solvent is condensed by the first condenser 320, part of it is returned to the top of the first distillation column 310 via the reflux pump, and the remainder enters the intermediate storage tank 510. The residual liquid at the bottom of the first distillation column 310 is discharged into the waste liquid treatment system 330. The outlet of the intermediate storage tank 510 is connected to the feed inlet of the first rectification column 410 for further purification of the solvent.

[0053] In one or more possible embodiments of this utility model, the distillation unit 400 includes a first distillation column 410, the inlet of the first distillation column 410 is connected to the outlet of the intermediate storage tank 510, a second condenser 420 is connected to the top of the first distillation column 410, the second condenser 420 is connected to the finished product storage tank 600 through a reflux ratio controller, the bottom of the first distillation column 410 is connected to the intermediate storage tank 510, and the finished product storage tank 600 is connected to the inlet of the reactor through a metering pump. Specifically, the second condenser 420 is provided at the top of the first distillation column 410 so that the purity of the condensate is adjusted by the reflux ratio controller, the high-purity solvent flows into the finished product storage tank 600, and the low-boiling-point impurities at the bottom of the first distillation column 410 are returned to the intermediate storage tank 510 for secondary processing; the finished product storage tank 600 is connected to the inlet of the reactor through a metering pump to realize solvent recycling.

[0054] The specific workflow of this utility model is as follows:

[0055] The mixture in the reactor enters the coarse filtration separation unit 110 to achieve preliminary separation of solid products and mother liquor. The solid products are retained, while the mother liquor flows into the mother liquor buffer tank 120 through the filtrate outlet. The mother liquor at the bottom of the mother liquor buffer tank 120 can be sent back to the reactor by a circulation pump, while the mother liquor at the top enters the filtration and adsorption unit 200 for further processing.

[0056] The mother liquor after the above treatment first enters the coarse filtration unit 210. Inside the coarse filtration housing 211, the mother liquor is guided by the frustum-shaped guide 212 and first undergoes coarse filtration by the first filter plate 213 to intercept larger particulate impurities. Then it flows through the filter membrane tube 216 to further filter out smaller particulate impurities. Next, the mother liquor enters the adsorption unit 220. Inside the adsorption housing 221, the mother liquor passes through a placement frame containing columnar coconut shell activated carbon with high specific surface area. The activated carbon adsorption component 222 adsorbs pigments, odor substances, organic impurities, etc. in the mother liquor. The filter screens 223 set at the upper and lower ends of the activated carbon adsorption component 222 prevent activated carbon particles from entering the subsequent process. Finally, the mother liquor enters the fine filtration unit 230. Inside the fine filtration housing 231, the molecular sieve component 232 performs deep filtration of the mother liquor to remove even finer impurities. At the same time, the electric heating component 234 heats the molecular sieve component 232 to maintain its activity and enable it to better remove water and other residual impurities from the mother liquor.

[0057] After filtration and adsorption treatment, the mother liquor enters the first distillation column 310. The solvent is evaporated by heating, and the vapor rises to the top and enters the first condenser 320. After being cooled and liquefied, part of it is returned to the first distillation column 310 by the reflux pump, and the other part flows into the intermediate storage tank 510. The residual impurities at the bottom of the first distillation column 310 are sent to the waste liquid treatment system 330.

[0058] The liquid in the intermediate storage tank 510 enters the first distillation column 410 for further separation and purification. The vapor at the top of the first distillation column 410 is cooled by the second condenser 420. Then, through the reflux ratio controller, part of it is returned to the first distillation column 410, and the other part flows into the finished product storage tank 600 to obtain a high-purity solvent product.

[0059] The liquid at the bottom of the first distillation column 410 is returned to the intermediate storage tank 510 for further distillation; the solvent in the finished product storage tank 600 can be sent back to the reactor by a metering pump to achieve solvent recycling.

[0060] The specific embodiments disclosed in this utility model fall within the protection scope of the claims of this utility model and are specific subordinate implementations of the feature parts of this utility model. The protection content of the specific embodiments is merely an explanation of the protection scope of the claims of this utility model. The protection scope of this utility model is not limited to the protection content of the specific embodiments, and the protection content of the specific embodiments should not be construed as a limitation on the protection scope of the claims of this utility model.

Claims

1. A gradient filtration solvent recovery apparatus, characterized by: Including: The solid-liquid separation unit is used for coarse filtration to separate solid products and treat the mother liquor with accumulated impurities, and is connected to the filtration and adsorption unit. A filtration and adsorption unit, used to trap, adsorb, and remove impurities from the mother liquor, is connected to a distillation unit. The filtration and adsorption unit includes a coarse filtration component, an adsorption component, and a fine filtration component connected in sequence. The coarse filtration component includes a coarse filter housing, within which a frustum-shaped flow guide is installed. A first filter plate is detachably mounted on the flow guide. The lower part of the flow guide is connected to a cylindrical mounting sleeve, the lower inner wall of which is provided with an annular base. A filter membrane tube is movably mounted inside the mounting sleeve. The adsorption component includes an adsorption housing, inside which an activated carbon adsorption assembly is installed. The activated carbon adsorption assembly includes a detachable... A placement frame is placed inside the adsorption shell, and the placement frame is filled with columnar coconut shell activated carbon with a specific surface area ≥1200m² / g. Filter screens are respectively provided at the upper and lower ends of the activated carbon adsorption component. The fine filtration component includes a fine filtration shell, and a molecular sieve component is installed inside the fine filtration shell. Several sets of evenly distributed and vertically arranged heating holes are opened on the molecular sieve component. An electric heating component is provided inside the fine filtration shell above the molecular sieve component. Each electric heating rod in the electric heating component is inserted into the corresponding heating hole, and the depth of insertion of each electric heating rod into the molecular sieve component is greater than 2 / 3 of the height of the molecular sieve component. The distillation unit is used to purify the solvent and is connected to the rectification unit and the waste liquid treatment system. The distillation unit, used to separate and purify the solvent, is connected to the finished product storage tank; The intermediate storage unit includes an intermediate storage tank, which is connected to the distillation unit and the rectification unit.

2. A gradient filtration solvent recovery device according to claim 1, wherein: The solid-liquid separation unit includes a coarse filtration separation component connected to the outlet of the reactor. The filtrate outlet of the coarse filtration separation component is connected to a mother liquor buffer tank via a pipeline. The bottom of the mother liquor buffer tank is connected to the reactor via a circulation pump, and the upper part of the mother liquor buffer tank is connected to a filtration and adsorption unit via a pipeline.

3. A gradient filtration solvent recovery device according to claim 1, wherein: The filter membrane tube has a membrane shell made of stainless steel, and the membrane shell contains an alumina-based ceramic membrane tube with multiple sets of pores and a pore size of 5-10μm.

4. A gradient filtration solvent recovery device according to claim 1, wherein: The filter screen has a pore size of 0.05-0.1mm.

5. A gradient filtration solvent recovery device according to claim 1, wherein: The distillation unit includes a first distillation column connected to the filtration and adsorption unit. The top of the first distillation column is connected to a first condenser. The first condenser is connected to an intermediate storage tank and the first distillation column via a reflux pump. The bottom of the first distillation column is connected to a waste liquid treatment system.

6. A gradient filtration solvent recovery device according to claim 1, wherein: The distillation unit includes a first distillation column, the feed inlet of which is connected to the outlet of an intermediate storage tank. A second condenser is connected to the top of the first distillation column, and the second condenser is connected to a finished product storage tank via a reflux ratio controller. The bottom of the first distillation column is connected to the intermediate storage tank, and the finished product storage tank is connected to the feed inlet of a reaction vessel via a metering pump.

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