Combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in PAN-CF polymerization experiment

Abstract

The present invention provides a combined recovery and treatment method for polymerization waste liquid and kettle washing waste liquid generated by a PAN-CF polymerization test, comprising the following steps: mixing the polymerization waste liquid and kettle washing waste liquid to obtain a mixed waste liquid; mixing the mixed waste liquid and a first emulsifier solution to obtain a mixed emulsion; separating and treating the mixed emulsion to obtain a target component and a second emulsifier solution, wherein the target component includes reactants and products of the polymerization test; and adding the obtained second emulsifier solution to the first emulsifier solution. In addition, the method also obtains a kettle washing solvent. The combined recovery and treatment method avoids gel or coking caused by directly heating and distilling or rectifying the high-viscosity polymerization waste liquid, and at the same time, the emulsifier is designed to be repeatedly recycled, thereby achieving efficient utilization of resources as a whole, and providing a strategy for reducing the production cost of polyacrylonitrile-based carbon fibers to further promote their market applications.

Description

Technical Field

[0001] The invention relates to the field of waste liquid recovery, and in particular to a method for jointly recovering and treating polymerization waste liquid and kettle washing waste liquid generated in a PAN-CF polymerization experiment. Background Art

[0002] Carbon fiber is known as "black gold" and the "king of new materials" in the 21st century for its excellent comprehensive properties such as high strength, high modulus, light weight, resistance to ultra-high and low temperatures, and corrosion resistance. Carbon fiber is widely used in aerospace, wind turbine blades, sports and leisure, pressure vessels, and construction. Although the application and demand of carbon fiber have increased year by year with the development of technology and the market over the years, the relatively high price of carbon fiber is still an important factor restricting its market application.

[0003] The relatively high price of carbon fiber is currently determined by its production cost. The production of polyacrylonitrile-based carbon fiber (PAN-CF), which currently has a market share of more than 90%, mainly includes polymerization, spinning, pre-oxidation and carbonization, and the production cost is composed of raw materials, power and equipment depreciation costs. The raw material input is mainly in the first stage of PAN-CF production, that is, the polymerization reaction of monomer acrylonitrile to produce polyacrylonitrile. Polymerization waste liquid is inevitably generated in the polymerization production of PAN-CF, especially during the polymerization test. In addition, the high viscosity of the polymerization liquid easily causes gel to adhere to the reactor wall, and the reactor needs to be cleaned during production to produce reactor washing waste liquid. Both the polymerization waste liquid and the reactor washing waste liquid contain the solvent dimethyl sulfoxide (DMSO), acrylonitrile monomer and polyacrylonitrile, but they cannot be used directly. If they are directly discarded and discharged, it will not only seriously pollute the environment, but also be a great waste of resources, while increasing the production cost of PAN-CF. Summary of the invention

[0004] The object of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a method for the combined recovery and treatment of polymerization waste liquid and kettle washing waste liquid generated in a PAN-CF polymerization experiment.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] The present invention provides a combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in a PAN-CF polymerization experiment, comprising the following steps:

[0007] Mixing the polymerization waste liquid and the kettle washing waste liquid to obtain a mixed waste liquid;

[0008] mixing the mixed waste liquid and the first emulsifier solution to obtain a mixed emulsion;

[0009] Separating the mixed emulsion to obtain a target component and a second emulsifier solution, wherein the target component includes reactants and products of the polymerization test;

[0010] The obtained second emulsifier solution is supplemented to the first emulsifier solution.

[0011] The polymerization waste liquid and the kettle washing waste liquid are mixed to obtain a mixed waste liquid, comprising:

[0012] At a temperature of 60 to 80° C., the polymerization waste liquid and the kettle washing waste liquid are mixed in a first preset weight ratio of 1:0.5 to 2, and stirred at a rotation speed of 50 to 120 rpm for 3 to 6 hours to obtain a mixed waste liquid.

[0013] Among them, the falling time of the mixed waste liquid is 5 to 20 seconds.

[0014] The first emulsifier solution includes a polyvinyl alcohol aqueous solution with a mass fraction of 5 to 12%.

[0015] The mixed waste liquid and the first emulsifier solution are mixed to obtain a mixed emulsion, comprising:

[0016] At a temperature of 25 to 30° C., the mixed waste liquid is added to the first emulsifier solution according to a second preset weight ratio of mixed waste liquid / first emulsifier solution = 1:1 to 2, the adding time is 30 to 90 minutes, and the mixture is stirred at a speed of 80 to 150 rpm during the adding process. After the adding is completed, the mixture is stirred at a speed of 80 to 150 rpm for 30 to 60 minutes to obtain a mixed emulsion.

[0017] After the mixed emulsion is separated, a kettle washing solvent is obtained.

[0018] Separation of mixed emulsions, including:

[0019] The mixed emulsion is subjected to reduced pressure distillation to obtain a first fraction and a first suspension; the first fraction is subjected to separation treatment to obtain water, reactants and a kettle washing solvent;

[0020] Separating the first suspension to obtain water, solid matter and kettle washing solvent;

[0021] Mixing water obtained by separating the first fraction, water obtained by separating the first suspension, and the solid matter to obtain a second suspension;

[0022] The second suspension is subjected to separation treatment to obtain a product and a second emulsifier solution.

[0023] The first fraction is subjected to separation treatment, comprising:

[0024] distilling the first fraction to obtain a second fraction and kettle liquid;

[0025] The second fraction is subjected to layering treatment, wherein the upper layer liquid is the reactant and the lower layer liquid is water;

[0026] The kettle liquid is distilled to obtain water and kettle washing solvent.

[0027] The first suspension is subjected to separation treatment, comprising:

[0028] filtering the first suspension to obtain a first filtrate and a first filter residue;

[0029] Filtering the first filtrate to obtain a second filtrate and a second filter residue;

[0030] The second filtrate is subjected to reduced pressure distillation to obtain a third fraction and solid particles;

[0031] The third fraction is distilled to obtain water and a kettle washing solvent;

[0032] The first filter residue, the second filter residue and the solid particles constitute the solid matter.

[0033] Supplementing the obtained second emulsifier solution to the first emulsifier solution comprises:

[0034] adjusting the emulsifier mass fraction of the second emulsifier solution to be the same as the emulsifier mass fraction of the first emulsifier solution;

[0035] The adjusted second emulsifier solution is added to the first emulsifier solution.

[0036] In the combined recovery and treatment method of the polymerization waste liquid and the kettle washing waste liquid generated by the PAN-CF polymerization test provided by the present invention, the polymerization waste liquid and the kettle washing waste liquid are first mixed to obtain a mixed waste liquid, and then the mixed waste liquid and the first emulsifier solution are mixed to obtain a mixed emulsion, and the mixed emulsion is separated and treated to obtain a target component and a second emulsifier solution; the target component includes the reactants and products of the polymerization test, which can be recycled, and the second emulsifier solution can be added to the first emulsifier solution for continued use. The combined recovery and treatment method is to mix and dilute the kettle washing waste liquid with the polymerization waste liquid to obtain a mixed waste liquid, emulsify the mixed waste liquid with the emulsifier solution to obtain a mixed emulsion, and separate the mixed emulsion to obtain the reactant acrylonitrile and the product polyacrylonitrile of the polymerization test, thereby avoiding gel or coking caused by directly heating and distilling or rectifying the high-viscosity polymerization waste liquid, and at the same time, the emulsifier is designed to be repeatedly recycled, and the efficient utilization of resources is achieved as a whole, providing a strategy for reducing the production cost of polyacrylonitrile-based carbon fiber to further promote its market application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A schematic diagram of a combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in a PAN-CF polymerization experiment according to an exemplary embodiment of the present invention;

[0039] Figure 2 A flow chart of separating a mixed emulsion according to an exemplary embodiment of the present invention;

[0040] Figure 3 A flow chart of separating the first fraction according to an exemplary embodiment of the present invention;

[0041] Figure 4 A flow chart of separating a first suspension according to an exemplary embodiment of the present invention;

[0042] Figure 5 This is a flow chart of adding the obtained second emulsifier solution to the first emulsifier solution according to an exemplary embodiment of the present invention;

[0043] Figure 6 This is a specific example flow chart of a method for jointly recovering and treating polymerization waste liquid and kettle washing waste liquid generated in a PAN-CF polymerization experiment according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0044] The technical scheme in the embodiment of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present invention.

[0045] Reference to an "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] In the related art, dimethyl sulfoxide (DMSO) is recovered from production wastewater, polymerization waste liquid and / or kettle washing waste liquid containing the solvent dimethyl sulfoxide (DMSO) by distillation and / or rectification. However, the high-temperature treatment process of direct distillation and / or rectification is very likely to cause polyacrylonitrile to coke, which adheres to the equipment and is difficult to remove, affecting the heat exchange efficiency.

[0047] Based on this, an exemplary embodiment of the present invention provides a combined recovery and treatment method for polymerization waste liquid and kettle washing waste liquid generated by PAN-CF polymerization test, such as Figure 1 As shown, the combined recovery and treatment method comprises the following steps:

[0048] Step S100: mixing the polymerization waste liquid and the kettle washing waste liquid to obtain a mixed waste liquid;

[0049] Step S200: mixing the mixed waste liquid and the first emulsifier solution to obtain a mixed emulsion;

[0050] Step S300: Separating the mixed emulsion to obtain a target component and a second emulsifier solution, wherein the target component includes reactants and products of the polymerization test;

[0051] Step S400: adding the obtained second emulsifier solution to the first emulsifier solution.

[0052] In the combined recovery and treatment method of the polymerization waste liquid and the kettle washing waste liquid generated by the PAN-CF polymerization test provided in this embodiment, the polymerization waste liquid and the kettle washing waste liquid are first mixed to obtain a mixed waste liquid, and then the mixed waste liquid is mixed with the first emulsifier solution to obtain a mixed emulsion, and the mixed emulsion is separated and treated to obtain the reactants, products and second emulsifier solution of the polymerization test, and the reactants and products of the polymerization test can be recovered, and the second emulsifier solution can be added to the first emulsifier solution for continued use. The combined recovery and treatment method is to mix and dilute the kettle washing waste liquid with the polymerization waste liquid to form a mixed waste liquid, emulsify the mixed waste liquid with the emulsifier solution to form a mixed emulsion, and separate the mixed emulsion to obtain the reactant acrylonitrile and product polyacrylonitrile of the polymerization test, thereby avoiding gel or coking caused by directly heating and distilling or rectifying the high-viscosity polymerization waste liquid, and at the same time, the emulsifier is designed to be repeatedly recycled, thereby achieving efficient utilization of resources as a whole.

[0053] Wherein, in step S100, the polymerization waste liquid and the kettle washing waste liquid are mixed to obtain a mixed waste liquid. In the polymerization production of PAN-CF, the high viscosity polymerization liquid easily causes gel to adhere to the kettle wall, so the reactor needs to be cleaned with a kettle washing solvent, and the kettle washing waste liquid generated after cleaning dilutes the polymerization waste liquid to form a mixed waste liquid, thereby avoiding the subsequent direct heating distillation and / or rectification of the polymerization waste liquid to produce gel or coke. Exemplarily, the kettle washing solvent can be a dimethyl sulfoxide (DMSO) organic solvent.

[0054] In step S200, the mixed waste liquid and the first emulsifier solution are mixed to obtain a mixed emulsion. The mixed waste liquid contains polyacrylonitrile macromolecules, and the addition of the emulsifier can open and disperse the agglomerated polyacrylonitrile macromolecules, which is convenient for subsequent separation treatment.

[0055] In step S300, the mixed emulsion is separated to obtain the target component and the second emulsifier solution, and the target component includes the reactants and products of the polymerization test. The first stage of PAN-CF production, i.e., the polymerization reaction of the monomer acrylonitrile to generate polyacrylonitrile, will produce unreacted acrylonitrile reactants and uncollected polyacrylonitrile products remaining in the polymerization waste liquid; the polymerization waste liquid is diluted and mixed with the waste liquid from the kettle washing, and then emulsified with an emulsifier to obtain a mixed emulsion, which is separated to recover the acrylonitrile reactants and polyacrylonitrile products, which can reduce production costs and save resources. In addition, the emulsifier is also separated in the separation process and recovered for use.

[0056] In step S400, the obtained second emulsifier solution is added to the first emulsifier solution. During the separation process of the mixed emulsion, the second emulsifier solution is separated and can be added to the first emulsifier solution to continue to participate in the subsequent joint recovery process to achieve the effect of recycling, reduce costs, and save resources.

[0057] In one embodiment of the present invention, the polymerization waste liquid and the kettle washing waste liquid are mixed to obtain the mixed waste liquid, including: at a preset temperature, the preset temperature range is 60-80°C, for example, 60°C, 70°C, 80°C, the polymerization waste liquid and the kettle washing waste liquid are mixed in a first preset weight ratio, the first preset weight ratio range is 1:0.5-2, for example, 1:0.5, 1:1, 1:1.5, 1:2, at a preset speed, the preset speed range is 50-120rpm, for example, 50rpm, 80rpm, 100rpm, 120rpm, stirring for a preset time, the preset time range is 3-6h, for example, 3h, 4h, 5h, 6h, to obtain the mixed waste liquid. This design allows the kettle washing waste liquid to fully dilute and mix the polymerization waste liquid, reduce the concentration and viscosity of the polymerization waste liquid, and avoid the subsequent direct heating distillation and / or rectification of the polymerization waste liquid to produce gel or coke.

[0058] In one embodiment of the present invention, the ball-falling time of the mixed waste liquid is 5 to 20 seconds, for example, 5 seconds, 10 seconds, 15 seconds, or 20 seconds. Within this ball-falling time range, the viscosity of the mixed waste liquid can meet the subsequent separation requirements, and it is not easy to produce gel or coke when heated. The ball-falling time is a parameter that characterizes the viscosity of a liquid. The ball-falling time is determined by using a ball-falling viscosity test tube of a specific specification (250 mL; height mark 20 cm) to hold a polymer liquid sample, placing a steel ball of a specific specification (φ2.0 mm; weight 7.0 g; stainless steel) in the test tube at 60°C and letting it fall vertically. The time it takes to pass through the upper and lower scale lines is recorded as the ball-falling time.

[0059] In one embodiment of the present invention, the first emulsifier solution includes a polyvinyl alcohol aqueous solution with a preset mass fraction, and the preset mass fraction ranges from 5 to 12%, for example, 5%, 8%, 10%, and 12%. The mixed waste liquid contains polyacrylonitrile macromolecules, and the addition of the emulsifier polyvinyl alcohol can open and disperse the agglomerated polyacrylonitrile macromolecules, which is convenient for subsequent separation treatment.

[0060] In one embodiment of the present invention, the mixed waste liquid and the first emulsifier solution are mixed to obtain a mixed emulsion, comprising: at a preset temperature, the preset temperature range is 25 to 30°C, for example, it can be 25°C, 28°C, 30°C, according to the second preset weight ratio of the mixed waste liquid / the first emulsifier solution, the second preset weight ratio range is 1:1 to 2, for example, it can be 1:1, 1:1.5, 1:2, the mixed waste liquid is added to the first emulsifier solution, and the adding time is 30 to 90 minutes, for example, it can be 30 minutes, 60 minutes, 90 minutes. During the adding process, the mixture is stirred at a preset speed, the preset speed range is 80-150rpm, for example, 80rpm, 100rpm, 120rpm, 150rpm, and after the adding is completed, the mixture is stirred at a preset speed, the preset speed range is 80-150rpm, for example, 80rpm, 100rpm, 120rpm, 150rpm, and the stirring time is preset, the preset time range is 30-60mins, for example, 30mins, 40mins, 50mins, 60mins, to obtain a mixed emulsion. This design can fully mix the mixed waste liquid and the first emulsifier solution to obtain a mixed emulsion, so that the agglomerated polyacrylonitrile macromolecules in the mixed emulsion are opened and dispersed, which is convenient for subsequent separation and treatment.

[0061] In one embodiment of the present invention, after the mixed emulsion is separated, a kettle washing solvent is also obtained. In the polymerization production of PAN-CF, the high viscosity of the polymer solution easily causes gel to adhere to the kettle wall, so the kettle washing solvent is required to clean the reactor, and the kettle washing waste liquid generated after the cleaning dilutes the polymerization waste liquid to form a mixed waste liquid, and the mixed waste liquid is emulsified to obtain a mixed emulsion. After the mixed emulsion is separated, the kettle washing solvent is also separated and can be added to the kettle washing solvent storage tank for continued recycling, thereby reducing costs and saving resources. Exemplarily, the kettle washing solvent can be an organic solvent such as dimethyl sulfoxide (DMSO).

[0062] like Figure 2As shown, in one embodiment, the mixed emulsion is separated and treated, including: performing vacuum distillation on the mixed emulsion to obtain a first fraction and a first suspension; performing separation treatment on the first fraction to obtain water, reactants and a kettle washing solvent; performing separation treatment on the first suspension to obtain water, solids and a kettle washing solvent; mixing the water obtained by the separation treatment of the first fraction, the water obtained by the separation treatment of the first suspension and the solids to obtain a second suspension; performing separation treatment on the second suspension to obtain a product and a second emulsifier solution. Exemplarily, the mixed emulsion is subjected to vacuum distillation at 60°C and a preset pressure, the preset pressure range is -(40~50)KPa, for example, it can be -40KPa, -45KPa, -50KPa, and the distillation is stopped when the gas phase temperature reaches 60°C, and the obtained first fraction is collected in a storage tank with a temperature of 0~5°C, for example, it can be collected in a storage tank with a temperature of 0°C, 3°C, 5°C, and a first suspension is also obtained. Exemplarily, the water obtained by separating the first fraction, the water obtained by separating the first suspension, and the solid matter are mixed at a preset temperature, the preset temperature range is 60 to 80°C, for example, 60°C, 70°C, 80°C, at a preset speed, the preset speed range is 30 to 80rpm, for example, 30rpm, 50rpm, 80rpm, stirring for a preset time, the preset time range is 6 to 8h, for example, 6h, 7h, 8h; after the stirring is completed, at the preset temperature, the preset temperature range is 60 to 80°C, for example, 60°C, 70°C, 80°C, at the preset pressure, the preset pressure range is -(90 ~100)KPa, for example, -90KPa, -95KPa, -100KPa, filtering, the mesh number of the filter medium is 400-1000 mesh, for example, it can be 400 mesh, 600 mesh, 800 mesh, 1000 mesh, to obtain a filtrate and a filter residue, the obtained filtrate is the second emulsifier solution, which can be added to the first emulsifier solution for recycling, the obtained filter residue is at a preset temperature, the preset temperature range is 80-90°C, for example, it can be 80°C, 85°C, 90°C, and dried for a preset time, the preset time range is 3-5h, for example, it can be 3h, 4h, 5h, and after drying, the product of the polymerization test, polyacrylonitrile, is obtained, which can be recycled.

[0063] like Figure 3As shown, in one embodiment, the first fraction is separated and treated, including: distilling the first fraction to obtain a second fraction and kettle liquid; layering the second fraction, wherein the upper layer liquid is the reactant and the lower layer liquid is water; and distilling the kettle liquid to obtain water and kettle washing solvent. Exemplarily, the first fraction is distilled, and the number of plates in the distillation tower is 10 to 15, for example, 10, 13, or 15, the number of plates in the stripping tower is 15 to 20, for example, 15, 17, or 20, the pressure is -(40 to 50) KPa, for example, -40 KPa, -45 KPa, or -50 KPa, the bottom temperature is 60 to 65°C, for example, 60°C, 63°C, or 65°C, the top temperature is 40 to 50°C, for example, 40°C, 45°C, or 50°C, the reflux ratio is 1.5 to 2.0, for example, 1.5, 1.8, or 2.0, the top of the tower is collected to obtain a second fraction, and the second fraction is subjected to layered treatment to obtain water and acrylonitrile, a reactant in the polymerization test. Exemplarily, the kettle liquid is distilled, and the number of plates in the distillation section of the distillation tower is 15 to 20, for example, 15, 17, or 20, the number of plates in the stripping section is 10 to 15, for example, 10, 13, or 15, the pressure is -(90 to 95) KPa, for example, -90 KPa, -93 KPa, or -95 KPa, the bottom temperature is 110 to 120°C, for example, 110°C, 115°C, or 120°C, the top temperature is 45 to 55°C, for example, 45°C, 50°C, or 55°C, the reflux ratio is 2.5 to 4.5, for example, 2.5, 3.0, 3.5, 4.0, or 4.5, and distillation obtains water and a kettle washing solvent, for example, the kettle washing solvent is dimethyl sulfoxide, and the kettle washing solvent can be added to a kettle washing solvent storage tank for recycling.

[0064] like Figure 4As shown, in one embodiment, the first suspension is subjected to separation treatment, including: filtering the first suspension to obtain a first filtrate and a first filter residue; filtering the first filtrate to obtain a second filtrate and a second filter residue; performing reduced pressure distillation on the second filtrate to obtain a third fraction and solid particles; rectifying the third fraction to obtain water and a kettle washing solvent; the first filter residue, the second filter residue and the solid particles constitute a solid matter. Exemplarily, at a preset temperature, the preset temperature range is 25 to 35°C, for example, it can be 25°C, 30°C, 35°C, and at a preset pressure, the preset pressure range is -(90 to 100) KPa, for example, it can be -90 KPa, -95 KPa, -100 KPa, the first suspension is filtered, the filter medium mesh number is 100 to 300 mesh, for example, it can be 100 mesh, 200 mesh, 300 mesh, to obtain a first filtrate and a first filter residue; at a preset temperature, the preset temperature range is 35 to 40°C, for example It can be 35°C, 38°C, 40°C, and under the preset pressure, the preset pressure range is -(90-100)KPa, for example, it can be -90KPa, -95KPa, -100KPa, the first filtrate is filtered, and the filter medium mesh number is 400-1000 mesh, for example, it can be 400 mesh, 600 mesh, 800 mesh, 1000 mesh, to obtain the second filtrate and the second filter residue; for the second filtrate at a temperature of 80°C, under the preset pressure, the preset pressure range is -(40-50)KPa, for example, it can be - 40KPa, -45KPa, -50KPa, carry out vacuum distillation, stop distillation when the gas phase temperature reaches 80°C, collect the third fraction in a storage tank with a temperature of 10-20°C, for example, it can be collected in a storage tank with a temperature of 10°C, 15°C, 20°C, and obtain solid particles at the bottom of the kettle; rectify the third fraction, the number of plates in the rectifying section of the rectifying tower is 15-20, for example, it can be 15, 18, 20, the number of plates in the stripping section is 10-15, for example, it can be 10, 12, 15, the pressure is -(90 ~95) KPa, for example, it can be -90 KPa, -93 KPa, -95 KPa, the bottom temperature is 110-120 ℃, for example, it can be 110 ℃, 115 ℃, 120 ℃, the top temperature is 45-55 ℃, for example, it can be 45 ℃, 50 ℃, 55 ℃, the reflux ratio is 2.5-4.5, for example, it can be 2.5, 3.0, 3.5, 4.0, 4.5, and distillation obtains water and kettle washing solvent, for example, the kettle washing solvent is dimethyl sulfoxide, and the kettle washing solvent can be added to the kettle washing solvent storage tank for recycling.

[0065] like Figure 5As shown, in one embodiment, the obtained second emulsifier solution is supplemented to the first emulsifier solution, including: adjusting the emulsifier mass fraction of the second emulsifier solution to be the same as the emulsifier mass fraction of the first emulsifier solution; and supplementing the adjusted second emulsifier solution to the first emulsifier solution. Exemplarily, the second emulsifier solution is quantitatively supplemented with water to adjust its mass fraction to be consistent with the mass fraction of the first emulsifier solution, wherein the quantitative water supplementation amount of the second emulsifier is calculated according to the following formula:

[0066]

[0067] Where m H2O is the amount of water to be added; m1 is the mass of the second emulsifier solution; ω is the mass fraction of the first emulsifier solution; ω1 is the mass fraction of the second emulsifier solution; wherein, ω1 is measured by the drying method, that is, a sample of the second emulsifier solution with a mass of mA is weighed, placed in a blast drying oven at 70°C, and dried to constant weight to obtain a residue with a mass of mB, then ω1=mB / mA; the amount of water to be added and the second emulsifier solution are stirred and mixed at a preset temperature, the preset temperature range is 25-35°C, for example, it can be 25°C, 30°C, 35°C, at a preset speed, the preset speed range is 30-80rpm, for example, it can be 30rpm, 50rpm, 70rpm, 80rpm, for a preset time, the preset time range is 2-4h, for example, it can be 2h, 3h, 4h, and then added to the first emulsifier solution.

[0068] like Figure 6 As shown, a specific example of the combined recovery and treatment method of the polymerization waste liquid and kettle washing waste liquid generated in a PAN-CF polymerization experiment is given below.

[0069] At 60°C, the polymerization waste liquid (ball falling time of about 30s) produced by the polyacrylonitrile-based carbon fiber polymerization experiment and the kettle washing waste liquid (kettle washing solvent is DMSO) were mixed in a mass ratio of 1:0.5, and stirred at a speed of 50 rpm for 4 hours to obtain a mixed system. Three samples of the mixed system were taken and the ball falling times were measured to be 6.7s, 6.4s, and 5.8s, respectively, to obtain a mixed waste liquid.

[0070] A polyvinyl alcohol aqueous solution with a mass fraction of 5.5% was prepared as the first emulsifier solution, and 1 mass part of the mixed waste liquid was pumped into 1 mass part of the above polyvinyl alcohol aqueous solution with a metering pump. The pumping time was controlled to be 30 minutes. During the pumping process, stirring was continuously carried out at a speed of 120 rpm. After the pumping was completed, stirring was continued at a speed of 120 rpm for 60 minutes to obtain a mixed emulsion.

[0071] The mixed emulsion was subjected to vacuum distillation at 60°C and -45KPa. The distillation was stopped when the gas phase temperature reached 60°C. The first fraction was collected in a storage tank at a temperature of 5°C at the top of the distillation kettle, and the first suspension was obtained at the bottom of the distillation kettle.

[0072] The first fraction was distilled, the number of plates in the distillation section of the distillation tower was 15, the number of plates in the stripping section was 20, the pressure was -45KPa, the bottom temperature was 65℃, the top temperature was 40℃, the reflux ratio was 1.7, the second fraction was collected at the top of the tower through a 5℃ cooling tank, and the kettle liquid was obtained at the bottom of the tower; the second fraction was separated by a heterogeneous high-efficiency separator to obtain water and acrylonitrile, the reactant of the polymerization test. The kettle liquid was distilled, the number of plates in the distillation section of the distillation tower was 18, the number of plates in the stripping section was 12, the pressure was -95KPa, the bottom temperature was 118℃, the top temperature was 46℃, the reflux ratio was 2.9, and finally water was obtained at the top of the tower and DMSO, the kettle washing solvent, was obtained at the bottom of the tower. The obtained DMSO was added to the kettle washing solvent storage tank for recycling.

[0073] The first suspension is filtered at 35°C and -95KPa (the mesh number of the filter medium is 200 meshes) to obtain a first filtrate and a first filter residue; the first filtrate is filtered at 30°C and -95KPa (the mesh number of the filter medium is 800 meshes) to obtain a second filtrate and a second filter residue; the second filtrate is subjected to reduced pressure distillation at 80°C and -45KPa, and the distillation is stopped when the gas phase temperature reaches 80°C, and the third fraction is collected in a storage tank at a temperature of 10°C at the top of the distillation kettle, and solid particles are obtained at the bottom of the kettle; the third fraction is distilled, the number of plates in the distillation section of the distillation tower is 18, the number of plates in the stripping section is 12, the pressure is -95KPa, the bottom temperature is 118°C, the top temperature is 46°C, the reflux ratio is 3.0, and finally water is obtained at the top of the tower, and DMSO, a washing kettle solvent, is obtained at the bottom of the tower, and the obtained DMSO is added to a washing kettle solvent storage tank for recycling.

[0074] The first filter residue, the second filter residue, the solid particles, the water obtained by separating the first fraction, and the water obtained by separating the first suspension were mixed at 75°C, and stirred at 60 rpm for 7 hours to obtain a second suspension. The second suspension was filtered at 70°C and -95 KPa (the filter medium mesh number was 1000 mesh) to obtain a filtrate and a filter residue. The obtained filtrate was the second emulsifier solution. Three portions of the second emulsifier solution with masses of 5.0 g, 9.0 g, and 13.0 g were taken respectively. , placed in a 70°C forced air drying oven, and dried to constant weight to obtain 0.3397g, 0.6118g, and 0.8845g respectively, and the mass fraction ω1 of the second emulsifier solution is 6.80%; 0.24 parts by mass of water and 1 part by mass of the second emulsifier solution are stirred and mixed at 35°C at a speed of 80rpm for 2h, and then added to the storage tank of the first emulsifier solution for recycling; the obtained filter residue is dried at 90°C for 5h to obtain the product of the polymerization test, polyacrylonitrile, which can be recycled.

[0075] High performance liquid chromatography measured the purities of the recovered acrylonitrile, the DMSO separated from the kettle liquid, and the DMSO separated from the third fraction to be 99.3%, 99.5%, and 99.6%, respectively; the ratio of the sum of the masses of acrylonitrile, the DMSO separated from the kettle liquid, the DMSO separated from the third fraction, and the dried polyacrylonitrile to the sum of the masses of the recovered polymerization waste liquid and the kettle washing waste liquid, i.e., the yield, was 97.1%.

[0076] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for the combined recovery and treatment of polymerization waste liquid and kettle washing waste liquid generated in a PAN-CF polymerization experiment, characterized in that: The following steps are involved: Mixing the polymerization waste liquid and the kettle washing waste liquid to obtain a mixed waste liquid; Mixing the mixed waste liquid and the first emulsifier solution to obtain a mixed emulsion; Separating the mixed emulsion to obtain a target component and a second emulsifier solution, wherein the target component includes the reactants and products of the polymerization test; Supplementing the obtained second emulsifier solution to the first emulsifier solution; After the mixed emulsion is separated, a kettle washing solvent is obtained; The separation treatment of the mixed emulsion comprises: The mixed emulsion is subjected to reduced pressure distillation to obtain a first fraction and a first suspension; the first fraction is subjected to separation treatment to obtain water, the reactant and a kettle washing solvent; Separating the first suspension to obtain water, solid matter and kettle washing solvent; Mixing water obtained by separating the first fraction, water obtained by separating the first suspension, and the solid matter to obtain a second suspension; performing separation treatment on the second suspension to obtain the product and the second emulsifier solution; The separation treatment of the first fraction comprises: distilling the first fraction to obtain a second fraction and kettle liquid; The second fraction is subjected to layering treatment, wherein the upper layer liquid is the reactant and the lower layer liquid is water; The kettle liquid is distilled to obtain water and the kettle washing solvent.

2. The combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in PAN-CF polymerization test according to claim 1 is characterized in that: The polymerization waste liquid and the kettle washing waste liquid are mixed to obtain a mixed waste liquid, comprising: At a temperature of 60 to 80° C., the polymerization waste liquid and the kettle washing waste liquid are mixed in a first preset weight ratio of 1:0.5 to 2, and stirred at a rotation speed of 50 to 120 rpm for 3 to 6 hours to obtain the mixed waste liquid.

3. The combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in PAN-CF polymerization test according to claim 2 is characterized in that: The ball falling time of the mixed waste liquid is 5 to 20 seconds.

4. The combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in PAN-CF polymerization test according to claim 1 is characterized in that: The first emulsifier solution includes a polyvinyl alcohol aqueous solution with a mass fraction of 5 to 12%.

5. The combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in PAN-CF polymerization test according to claim 1 is characterized in that: The mixed waste liquid and the first emulsifier solution are mixed to obtain a mixed emulsion, comprising: At a temperature of 25 to 30° C., according to a second preset weight ratio of the mixed waste liquid / the first emulsifier solution = 1:1 to 2, the mixed waste liquid is added to the first emulsifier solution for 30 to 90 minutes. During the addition process, the mixture is stirred at a speed of 80 to 150 rpm. After the addition is completed, the mixture is stirred at a speed of 80 to 150 rpm for 30 to 60 minutes to obtain the mixed emulsion.

6. The combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in PAN-CF polymerization test according to claim 1 is characterized in that: The separation treatment of the first suspension comprises: filtering the first suspension to obtain a first filtrate and a first filter residue; Filtering the first filtrate to obtain a second filtrate and a second filter residue; performing reduced pressure distillation on the second filtrate to obtain a third fraction and solid particles; distilling the third fraction to obtain water and a kettle washing solvent; The first filter residue, the second filter residue and the solid particles constitute the solid matter.

7. The combined recovery and treatment method of polymerization waste liquid and kettle washing waste liquid generated in PAN-CF polymerization test according to claim 1 is characterized in that: The step of adding the obtained second emulsifier solution to the first emulsifier solution comprises: adjusting the emulsifier mass fraction of the second emulsifier solution to be the same as the emulsifier mass fraction of the first emulsifier solution; The adjusted second emulsifier solution is added to the first emulsifier solution.

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