A device and method for polymer solution desolidsification

Abstract

The application discloses a device and a method for removing single of polymerization stock solution, the device comprises a tank body and a spiral flow guide channel arranged in the tank body, the spiral flow guide channel comprises a spiral bottom plate and two spiral baffles, the two spiral baffles are arranged on the two sides of the spiral bottom plate and are arranged upwards; the inside of the spiral flow guide channel is a hollow structure, and the hollow structure is used for heat medium flow. In the method, the polymerization stock solution flows from top to bottom on the surface of the spiral flow guide channel, and the heat medium flows from bottom to top in the inside of the spiral flow guide channel. The device and the method mainly solve the problems that the existing single removal equipment in the acrylic fiber and carbon fiber industries can only be heat-insulated or heated through an outer jacket, the temperature of the material in the inside of the single removal equipment cannot be directly adjusted, the temperature difference of the material in the inside of the single removal equipment is large due to evaporation heat absorption, and the single removal effect is poor, the inside of the equipment is prone to skinning, frequent parking and cleaning are needed and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-performance fiber preparation, and particularly relates to polymerization solution single removal, and in particular to a device and method for polymerization solution single removal. BACKGROUND

[0002] The polymerization product, i.e. polymerization solution, from the polymerization kettle must be single removed, otherwise the polymerization will continue slowly, causing the viscosity of the polymerization solution to increase. The polymerization solution after single removal is called spinning solution. If the spinning solution containing a large amount of monomers is directly spun, the monomer vapor will escape when the spinning solution flows out of the spinneret due to gasification, which not only deteriorates the working conditions, but also seriously affects the quality of the original wire.

[0003] The existing polymer solution single removal or devolatilization method usually adopts equipment such as screw, static umbrella, dynamic scraper and falling film. The improvement direction can be summarized into two aspects: 1. Increase the devolatilization interface area; 2. Increase the devolatilization interface update rate.

[0004] CN103122488A discloses a small single removal tower, which adopts a stainless steel container. A feeding port is arranged at the top end of the tower body. Two vacuum extraction ports and a vacuum gauge for displaying the vacuum degree are arranged on the left and right sides of the feeding port. The feeding port is connected to a guide pipe in the middle of the tower body. The guide pipe is divided into an inner layer and an outer layer. An umbrella-shaped conical surface is arranged above the guide pipe inside the tower body. A semi-elliptical plate is arranged below the conical surface. The upper surface of the semi-elliptical plate is connected to the outer guide pipe, and the lower surface is connected to the inner guide pipe. The invention has a simple structure, and the semi-elliptical plate increases the evaporation area of the solution. However, the specific surface is small, the equipment volume is large, the interface update rate is slow, and the efficiency is low.

[0005] CN101856570A discloses a dynamic single removal and defoaming method and device for carbon fiber spinning solution. An ultrasonic generator is installed in the center of the defoaming kettle. A gas guide cylinder and a flow guide disc are arranged on the shunt gas guide cover. The defoaming effect is improved by heating the single removal and defoaming device, continuously feeding, gravity single removal and defoaming, film spreading defoaming, and ultrasonic auxiliary defoaming, and controlling the defoaming temperature, vacuum degree and single removal tower speed. This solves the problem of interface update rate of a part of static umbrella. However, this equipment has high processing precision requirements, and the effect is unstable in actual use. The liquid film is difficult to control.

[0006] CN1321793C discloses a method for devolatilization of a polymer composition by using a screw devolatilization extruder having a barrel and a screw rotatably supported in the barrel, the barrel having a polymer composition supply port, a polymer outlet, and a volatile component outlet, the polymer composition containing a polymer and a volatile component being supplied to the devolatilization extruder from the polymer composition supply port, the volatile component being discharged from the volatile component outlet, and the polymer being obtained from the polymer outlet. Compared with the above two, the patent has a fast material interface renewal speed and a large processing capacity, but has the problem of being limited by the equipment, the material stays in the devolatilization port for a short time, and is only suitable for removing a low content of volatile components or for occasions with a low requirement for the content of residual volatile components.

[0007] CN104028008A discloses a device for stripping devolatilization of a sieve plate or grid filler, which is operated under normal pressure and has a large steam consumption. The steam temperature of DMSO under normal pressure is about 189℃, which can seriously change the properties of the polymer at high temperatures. Therefore, the method is not suitable for the devolatilization of polyacrylonitrile spinning solution.

[0008] CN105037619A discloses a method for devolatilization of polyacrylonitrile spinning solution. The polyacrylonitrile polymerization solution flows from above the filler at the top of the filler tower through a material distributor, solvent vapor is introduced into the filler below the tower under negative pressure, the solvent vapor passes through the filler layer from bottom to top and exchanges with the polyacrylonitrile polymerization solution flowing from above, the residual volatile monomer in the polyacrylonitrile polymerization solution is carried away by the vacuum system, and the devolatilization is completed. The patent uses a filler tower, which is prone to dead angles and skinning.

[0009] The existing devolatilization method can only heat the devolatilization equipment by an outer jacket if no solvent vapor is added to the interior of the devolatilization equipment, and cannot directly adjust the temperature of the material in the interior of the devolatilization equipment. The material in the interior of the devolatilization equipment is prone to skinning and needs to be frequently stopped and cleaned due to a large temperature difference caused by evaporation and heat absorption. If solvent vapor is added to the interior of the devolatilization equipment, the devolatilization effect is improved and skinning is reduced, but the problem of a large temperature difference caused by evaporation and heat absorption in the interior of the devolatilization equipment is almost not improved, and the investment, land occupation, and operation cost of the equipment are increased. SUMMARY

[0010] In order to overcome the problems in the prior art, the present application provides a device and a method for devolatilization of a polymer solution, which mainly solves the problems that the existing devolatilization equipment in the acrylic fiber and carbon fiber industries can only heat the equipment by an outer jacket and cannot directly adjust the temperature of the material in the interior of the devolatilization equipment, the material in the interior of the devolatilization equipment is prone to skinning and needs to be frequently stopped and cleaned due to a large temperature difference caused by evaporation and heat absorption.

[0011] One of the purposes of the present application is to provide a device for monomer removal from polymerization solution, which comprises a tank body and a spiral flow guide channel arranged in the tank body.

[0012] In a preferred embodiment, the spiral flow guide channel is one or more.

[0013] In a further preferred embodiment, when the spiral flow guide channel is multiple, the multiple spiral flow guide channels are connected in parallel or in series, preferably in parallel.

[0014] In the present application, the spiral flow guide channels can be multiple in parallel. According to the volumetric flow rate of the polymerization solution and the film thickness, the number of parallel connections is calculated, and the upper part of the parallel spiral flow guide channels has a distributor (one or more branches), and the lower part has a collector (E in the figure). Figure 1 In the present application, the spiral flow guide channels can be multiple in series. According to the content of unconverted residual monomers in the polymerization solution stream and the heat transfer amount with the heat medium, the number of series connections is calculated.

[0015] In a further preferred embodiment, the one or more spiral flow guide channels are connected to the polymerization solution inlet through a polymerization solution distributor, preferably, the polymerization solution distributor comprises one or more branches, and when multiple branches are included, the multiple branches form a dendritic structure.

[0016] In a preferred embodiment, a polymerization solution inlet is arranged at the upper part or top of the tank body, the spiral flow guide channel comprises one spiral bottom plate and two spiral baffles, wherein the two spiral baffles are arranged on both sides of the spiral bottom plate and upwardly, so that the cross section of the spiral flow guide channel in the direction perpendicular to the spiral bottom plate is in the shape of a U.

[0017] The spiral baffles can be arranged vertically on the spiral bottom plate, or slightly inclined on the spiral bottom plate, which can be inwardly inclined or outwardly inclined.

[0018] In a further preferred embodiment, the upper surface of the spiral flow guide channel (preferably the spiral bottom plate) forms a surface channel for the flow of polymerization solution; and / or the interior of the spiral flow guide channel (preferably the interior of the spiral bottom plate) is a hollow structure, which forms an internal flow passage for the flow of heat medium.

[0019] In a further preferred embodiment, the interior of the spiral-shaped bottom plate is a hollow structure, and the interior of the spiral-shaped baffle is optionally a hollow structure, and when the interior of the spiral-shaped baffle is a hollow structure, it is preferred that the hollow structure is in communication with the hollow structure of the spiral-shaped bottom plate.

[0020] In a preferred embodiment, the height of the spiral-shaped baffle is ≤70 mm, preferably ≤60 mm, and more preferably ≤50 mm.

[0021] In a preferred embodiment, the ratio of the volumetric flow rate of the polymerization solution to the area of the spiral-shaped bottom plate is 1 mm to 30 mm, preferably 2 mm to 25 mm, and more preferably 5 mm to 20 mm.

[0022] For example, the ratio of the volumetric flow rate of the polymerization solution to the area of the spiral-shaped bottom plate is 1 mm, 2 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, or 30 mm.

[0023] In a preferred embodiment, the viscosity of the polymerization solution is 1 to 200 Pa.s, preferably 1 to 180 Pa.s, and more preferably 1 to 150 Pa.s.

[0024] For example, the viscosity of the polymerization solution is 1, 20, 50, 80, 100, 120, 150, 180, or 200 Pa.s.

[0025] In a preferred embodiment, a polymerization solution inlet is provided at the upper portion or top of the tank body, and the one or more spiral flow guide channels are connected to the polymerization solution inlet via a polymerization solution distributor.

[0026] In a further preferred embodiment, the upper end of the polymerization solution distributor is connected to the polymerization solution inlet, and the other end is in contact with the surface of the spiral flow guide channel, preferably the surface of the spiral-shaped bottom plate.

[0027] In this way, the polymerization solution can be guided to the surface flow channel of the spiral flow guide channel.

[0028] In a preferred embodiment, a heat medium inlet is provided at the lower portion or bottom of the tank body; and / or, a heat medium outlet is provided at the upper portion of the tank body.

[0029] Preferably, the temperature difference of the heat medium entering and exiting the tank body is ≤7℃, preferably ≤6℃, and more preferably ≤5℃.

[0030] In a further preferred embodiment, the heat medium inlet is in communication with the lower end of the internal channel of the spiral flow guide channel via a heat medium distributor, and preferably, the heat medium distributor comprises one or more branches, and when comprising multiple branches, the multiple branches form a dendritic structure.

[0031] In this way, the heat medium can enter the hollow structure of the spiral flow guide channel from the lower part of the tank body.

[0032] In a further preferred embodiment, the heat medium outlet is in communication with the internal flow passage (preferably the upper end thereof) of the spiral flow guide channel through a pipeline.

[0033] In this way, the heat medium can exit the hollow structure of the spiral flow guide channel from the upper part of the tank body.

[0034] In a preferred embodiment, the heat medium outlet is connected to the heat medium inlet through a circulation pipeline.

[0035] In a further preferred embodiment, a booster device (e.g. a booster pump) and a heat exchanger are arranged on the circulation pipeline (preferably in sequence along the flow direction of the heat medium).

[0036] In a preferred embodiment, a spinning dope outlet is arranged at the bottom of the tank body.

[0037] In a preferred embodiment, a vacuum extraction port is arranged at the upper part or top of the tank body.

[0038] In a further preferred embodiment, the upper end of the spiral flow guide channel is at a distance ≥ 500 mm, preferably ≥ 800 mm, more preferably ≥ 1000 mm, from the tangent of the vacuum extraction port.

[0039] In this way, the material can be prevented from being extracted into the vacuum pipeline.

[0040] In the present application, the device is used as follows: after the polymerization dope stream is fed into the inside of the singling device from the upper part or top (polymerization dope inlet) of the singling device, the polymerization dope is fed into the surface flow passage of the spiral flow guide channel through one or more branch pipes; after the heat medium stream is fed into the inside of the singling device from the lower part or bottom (heat medium inlet) of the singling device, the heat medium is fed into the internal flow passage of the spiral flow guide channel through one or more branch pipes; the polymerization dope stream and the heat medium stream are heated by heat conduction, the heat conduction is carried out on the spiral flow guide channel, the polymerization dope flows spirally from top to bottom in the surface flow passage of the spiral flow guide channel, and the heat medium flows spirally from bottom to top in the internal flow passage of the spiral flow guide channel; the upper part or top of the singling device is provided with a vacuum extraction port, and a vacuum stream is discharged from the vacuum extraction port; the lower part or bottom of the singling device is provided with a spinning dope outlet, and a spinning dope stream is discharged from the spinning dope outlet, thus preferably solving the aforementioned problems, and being applicable to the production processes of acrylic fibers, carbon fibers, etc., and having the advantages of good singling effect, flexible adjustment of the temperature of the material inside the singling tower, difficulty in skinning, and long running time.

[0041] The second object of the present application is to provide a method for the single removal of polymerization stock, which uses the device of the first object of the present application.

[0042] In a preferred embodiment, the method comprises:

[0043] (1) introducing the polymerization stock into the tank from the polymerization stock inlet of the single removal device, while introducing the heat medium stream into the tank from the heat medium inlet of the single removal device;

[0044] (2) spirally flowing the polymerization stock from top to bottom on the surface flow channel, and spirally flowing the heat medium from bottom to top in the inner flow channel;

[0045] (3) discharging the spinning stock stream from the spinning stock outlet, and discharging the heat medium outlet and recycling it back to the heat medium inlet.

[0046] In a preferred embodiment, in step (1), the polymerization stock stream is introduced into the tank from the polymerization stock inlet of the single removal device, and is sent into the surface flow channel of the spiral flow channel through the guide of one or more branches; and / or, the heat medium stream is sent into the tank from the heat medium inlet of the single removal device, and is sent into the inner flow channel of the spiral flow channel through the guide of one or more branches.

[0047] In a preferred embodiment, in step (2), the polymerization stock stream and the heat medium stream conduct heat through heat conduction, and the heat conduction is conducted on the spiral flow channel.

[0048] In a preferred embodiment, in step (3), the heat medium outlet is discharged and recycled back to the heat medium inlet after being subjected to pressurization and heat exchange in sequence.

[0049] In a further preferred embodiment, the heat medium outlet is recycled back to the heat medium inlet after being subjected to heat exchange to 72-100℃.

[0050] In a preferred embodiment, the method further comprises discharging the vacuum stream from the vacuum outlet.

[0051] In a preferred embodiment, the ratio of the volumetric flow rate of the polymerization stock to the area of the spiral-shaped bottom plate is 1-30 mm, preferably 2-25 mm, and more preferably 5-20 mm.

[0052] In a preferred embodiment, the viscosity of the polymerization stock is 1-200 Pa.s, preferably 1-180 Pa.s, and more preferably 1-150 Pa.s.

[0053] In a preferred embodiment, the temperature difference of the heat medium entering and exiting the tank body is ≤7℃, preferably ≤6℃, and more preferably ≤5℃.

[0054] In a preferred embodiment, the specific heat capacity of the heat medium is ≥ 0.6 KJ / (Kg*K), preferably ≥ 0.8 KJ / (Kg*K), more preferably ≥ 1.0 KJ / (Kg*K).

[0055] In a further preferred embodiment, the heat medium is selected from water or heat conducting oil.

[0056] In a preferred embodiment, the flow rate of the heat medium needs to satisfy

[0057] The following conditions:

[0058] Wmix*(1-Ps-Pp)*613.94=A*Cp*Wr*Δt

[0059] wherein Wmix: flow rate of the polymerization solution entering the single device, kg / h; Ps: weight content of the solvent in the polymerization solution; Pp: weight content of the polymer in the polymerization solution; Wr: flow rate of the heat medium, kg / h; Δt: temperature difference of the heat medium entering and exiting the single device; Cp: specific heat capacity of the heat medium; and A: proportional coefficient, 0.4-0.7.

[0060] In a preferred embodiment, the operating pressure in the tank is 0.1-10 KPaA, preferably 0.5-6 KPaA, more preferably 0.6-5 KPaA.

[0061] For example, the operating pressure in the tank is 0.1 KPaA, 0.5 KPaA, 1 KPaA, 2 KPaA, 3 KPaA, 4 KPaA, 5 KPaA, 6 KPaA, 7 KPaA, 8 KPaA, 9 KPaA or 10 KPaA.

[0062] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The endpoints of the ranges are included in the ranges themselves. Any numerical value, however, can inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Also, the endpoints of the ranges and the separate values are not to be understood as limited to the exact values shown. The ranges are understood to include values near these endpoints, as well as the exact values themselves. In this context, each technical solution can be combined with each other technical solution to form a new technical solution, which should also be considered as specifically disclosed herein.

[0063] Compared with the prior art, the present application has the following beneficial effects:

[0064] (1) The device and method of the present application mainly solve the problem that the existing single-removing equipment in the acrylic fiber and carbon fiber industry can only be heated by an outer jacket, and cannot directly adjust the temperature of the material inside the single-removing equipment. The large temperature difference caused by evaporation heat absorption inside the single-removing equipment causes poor single-removing effect, easy skinning inside the equipment, and the need for frequent parking and cleaning.

[0065] (2) The device and method of the present application solve the above problems and can be used in the production process of acrylic fiber, carbon fiber, etc. It has the advantages of good single-removing effect, flexible adjustment of the temperature of the material inside the single-removing tower, not easy to skin, and long running time. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 The structure diagram of the single-removing device of the present application is shown.

[0067] Figure 2 The structure diagram of the spiral flow guide channel of the present application is shown.

[0068] Figure 3 The local structure diagram of the spiral flow guide channel is shown.

[0069] Figure 1 、 Figure 2 、 Figure 3 Label description:

[0070] 101, polymeric solution stream

[0071] 102, vacuum stream

[0072] 103, spinning solution stream

[0073] 104, heat medium stream feed

[0074] 105, heat medium stream discharge

[0075] 106, pressurized heat medium stream

[0076] 107, hot fluid stream

[0077] 108, heat-exchanged hot fluid stream

[0078] 109, collector

[0079] A, tank body

[0080] B, spiral flow guide channel

[0081] B1, spiral flow guide channel surface flow passage

[0082] B2, spiral flow guide channel internal flow passage

[0083] B3, spiral flow guide channel surface flow passage side baffles

[0084] C. Heat exchanger

[0085] D. Booster pump

[0086] E. Collector

[0087] In the present application, the polymerization solution stream 101 is fed into the tank from the upper part or top of the tank body, and then the polymerization solution is fed into the surface flow channel B1 of the spiral flow guide channel B through the polymerization solution distributor (one or more branches); the heat medium stream 104 is fed into the tank from the lower part or bottom of the tank body, and then the heat medium is fed into the internal flow channel B2 of the spiral flow guide channel B through the heat medium distributor (one or more branches); the polymerization solution stream 101 and the heat medium stream 104 conduct heat through heat conduction, which is carried out on the spiral flow guide channel B, the polymerization solution flows spirally from top to bottom in the surface flow channel of the spiral flow guide channel, and the heat medium flows spirally from bottom to top in the internal flow channel of the spiral flow guide channel; the upper part or top of the tank body is provided with a vacuum outlet, and the vacuum stream 102 is discharged from the vacuum outlet; the lower part or bottom of the tank body is provided with a spinning solution outlet, and the spinning solution stream 103 is discharged from the spinning solution outlet. DETAILED DESCRIPTION

[0088] It is necessary to point out here that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments to the present application made by those skilled in the art based on the content of the present application still fall within the protection scope of the present application.

[0089] In addition, it should be noted that each specific technical feature described in the following specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

[0090] Furthermore, various different embodiments of the present application can also be combined in any manner, as long as they do not contradict the idea of the present application, and the technical solutions thus formed are part of the original disclosure of the present specification and also fall within the protection scope of the present application.

[0091] For example, in a production device with a capacity of hundreds of tons, the polymerization kettle sends a polymerization solution with a mass flow rate of 150 kg / h and a viscosity of 20 Pa.s, wherein the solvent content in the polymerization solution is 0.79 (i.e. 79%), and the content of polymers with a polymerization degree greater than 50 in the polymerization solution is 0.19 (i.e. 19%), i.e. the content of unconverted monomers before single removal is 20,000 ppm.

[0092]

Example 1

[0093] As Figure 1The internal operating pressure of the singling device is 0.7 KPaA, the distance between the upper end of the surface flow channel of the internal spiral flow guide channel of the singling device and the tangent of the vacuum extraction port is 2000 mm, the heat medium is water, the specific heat capacity Cp is 4.18 kJ / (kg·K), the ratio of the volume flow of the polymerization stock solution to the surface flow channel area of the spiral flow guide channel is 20 mm, the height of the baffle on both sides of the surface flow channel of the spiral flow guide channel is 50 mm, the temperature difference of the heat medium entering and exiting the singling device is 3°C, and the temperature range of the hot fluid flow is 75°C. The proportionality coefficient A is 0.6, and the heat medium flow is calculated to be 163.2 kg / h.

[0094] After singling, the monomer content is 510 ppm, the continuous running time of the singling device is 4000 h, and the internal skinning phenomenon of the equipment.

[0095]

Example 2

[0096] As shown in Figure 1 , the internal operating pressure of the singling device is 1.0 KPaA, the distance between the upper end of the surface flow channel of the internal spiral flow guide channel of the singling device and the tangent of the vacuum extraction port is 1800 mm, the heat medium is water, the specific heat capacity Cp is 4.18 kJ / (kg·K), the ratio of the volume flow of the polymerization stock solution to the surface flow channel area of the spiral flow guide channel is 16 mm, the height of the baffle on both sides of the surface flow channel of the spiral flow guide channel is 45 mm, the temperature difference of the heat medium entering and exiting the singling device is 3°C, and the temperature range of the hot fluid flow is 80°C. The proportionality coefficient A is 0.5, and the heat medium flow is calculated to be 195.83 kg / h.

[0097] After singling, the monomer content is 520 ppm, the continuous running time of the singling device is 4000 h, and the internal skinning phenomenon of the equipment.

[0098]

Example 3

[0099] As shown in Figure 1 , the internal operating pressure of the singling device is 1.5 KPaA, the distance between the upper end of the surface flow channel of the internal spiral flow guide channel of the singling device and the tangent of the vacuum extraction port is 1600 mm, the heat medium is water, the specific heat capacity Cp is 4.18 kJ / (kg·K), the ratio of the volume flow of the polymerization stock solution to the surface flow channel area of the spiral flow guide channel is 12 mm, the height of the baffle on both sides of the surface flow channel of the spiral flow guide channel is 40 mm, the temperature difference of the heat medium entering and exiting the singling device is 4°C, and the temperature range of the hot fluid flow is 85°C. The proportionality coefficient A is 0.4, and the heat medium flow is calculated to be 183.6 kg / h.

[0100] After singling, the monomer content is 530 ppm, the continuous running time of the singling device is 4000 h, and the internal skinning phenomenon of the equipment.

[0101]

Example 4

[0102] As shown in Figure 1As shown, the internal operating pressure of the polymerization device is 2.0 kPaA. The tangential distance between the upper end of the surface channel of the spiral guide channel and the vacuum port is 1400 mm. The heat transfer medium is water with a specific heat capacity Cp of 4.18 kJ / (kg·K). The ratio of the volumetric flow rate of the polymerization raw material to the surface area of ​​the spiral guide channel is 8 mm². The height of the baffles on both sides of the surface channel of the spiral guide channel is 35 mm. The temperature difference between the heat transfer medium entering and exiting the polymerization device is 4 °C. The temperature range of the hot fluid is 90 °C. With a proportionality coefficient A of 0.4, the calculated heat transfer medium flow rate is 183.6 kg / h.

[0103] After the monomers were removed, the monomer content was 535 ppm. The monomer removal device operated continuously for 4000 hours, and there was a descaling phenomenon inside the equipment.

[0104]

Example 5

[0105] like Figure 1 As shown, the internal operating pressure of the polymerization device is 3.0 kPaA. The tangential distance between the upper end of the surface channel of the spiral guide channel inside the device and the vacuum port is 1200 mm. The heat transfer medium is water with a specific heat capacity Cp of 4.18 kJ / (kg·K). The ratio of the volumetric flow rate of the polymerization raw material to the surface area of ​​the spiral guide channel is 6 mm². The height of the baffles on both sides of the surface channel of the spiral guide channel is 30 mm. The temperature difference between the heat transfer medium entering and exiting the polymerization device is 5 °C. The temperature range of the hot fluid is 95 °C. The proportionality coefficient A is 0.7, and the calculated heat transfer medium flow rate is 83.9 kg / h.

[0106] After the monomers were removed, the monomer content was 550 ppm. The monomer removal device operated continuously for 4000 hours, and there was a descaling phenomenon inside the equipment.

[0107]

Example 6

[0108] like Figure 1 As shown, the internal operating pressure of the polymerization device is 4.0 kPaA. The tangential distance between the upper end of the surface channel of the spiral guide channel inside the device and the vacuum port is 1000 mm. The heat transfer medium is water with a specific heat capacity Cp of 4.18 kJ / (kg·K). The ratio of the volumetric flow rate of the polymerization raw material to the surface area of ​​the spiral guide channel is 5 mm². The height of the baffles on both sides of the surface channel of the spiral guide channel is 30 mm. The temperature difference between the heat transfer medium entering and exiting the polymerization device is 5 °C. The temperature range of the hot fluid is 100 °C. The proportionality coefficient A is 0.65, and the calculated heat transfer medium flow rate is 90.4 kg / h.

[0109] After the monomers were removed, the monomer content was 560 ppm. The monomer removal device operated continuously for 4000 hours, and there was a descaling phenomenon inside the equipment.

[0110] The present application is described in detail above with reference to specific embodiments and exemplary examples, but these are not to be understood as limiting the present application. It is understood by a person skilled in the art that various equivalent substitutions, modifications or improvements can be made to the technical solutions of the present application and the embodiments thereof without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims.

Claims

1. A method for polymer solution depolymerization, using a depolymerization device, the depolymerization device comprising a tank body and a spiral flow guide channel arranged in the tank body, the upper surface of the spiral flow guide channel forming a surface channel for the flow of polymer solution, the interior of the spiral flow guide channel being a hollow structure forming an internal flow passage for the flow of heat medium; a polymer solution inlet is arranged at the upper part or top of the tank body, a spinning solution outlet is arranged at the bottom of the tank body, a heat medium inlet is arranged at the lower part or bottom of the tank body, and a heat medium outlet is arranged at the upper part of the tank body; The method comprises: (1) introducing polymer solution from the polymer solution inlet of the depolymerization device into the tank, the viscosity of the polymer solution being 1-20 Pa.s, and at the same time, introducing heat medium flow from the heat medium inlet of the depolymerization device into the tank; (2) the polymer solution flows spirally from top to bottom in the surface flow passage, and the heat medium flows spirally from bottom to top in the internal flow passage; (3) discharging spinning solution flow from the spinning solution outlet, and discharging heat medium from the heat medium outlet and circulating back to the heat medium inlet; The flow rate of the heat medium needs to satisfy the following condition in terms of weight percentage: Wmix*(1-Ps-Pp)*613.94=A*Cp*Wr*Δt wherein Wmix is the flow rate of the polymer solution entering the depolymerization device, kg / h; Ps is the weight content of solvent in the polymer solution; Pp is the weight content of polymer in the polymer solution; Wr is the flow rate of the heat medium, kg / h; Δt is the temperature difference of the heat medium entering and leaving the depolymerization device, Cp is the specific heat capacity of the heat medium, and A is a proportional coefficient, 0.4-0.

7.

2. The method of claim 1, wherein, The spiral flow guide channel is one or more, and when there are multiple spiral flow guide channels, the multiple spiral flow guide channels are connected in parallel or in series.

3. The method of claim 2, wherein, The one or more spiral flow guide channels are connected with the polymer solution inlet through a polymer solution distributor.

4. The method of claim 3, wherein, The polymer solution distributor comprises one or more branch pipes, and when there are multiple branch pipes, the multiple branch pipes form a dendritic structure.

5. The method of claim 1, wherein, The spiral flow guide channel comprises a spiral bottom plate and two spiral baffles, wherein the two spiral baffles are arranged on both sides of the spiral bottom plate and upwardly, so that the cross section of the spiral flow guide channel in the direction perpendicular to the spiral bottom plate is in the shape of a right U.

6. The method of claim 5, wherein, The interior of the spiral bottom plate is a hollow structure, and the interior of the spiral baffle is a hollow structure communicating with the hollow structure of the spiral bottom plate. 7.The method according to claim 5, wherein the height of the spiral baffle is ≤70 mm; and / or the ratio of the volume flow rate of the polymer solution to the area of the spiral bottom plate is 1-30 mm. 8.The method according to claim 5, wherein the height of the spiral baffle is ≤60 mm; and / or the ratio of the volume flow rate of the polymer solution to the area of the spiral bottom plate is 2-25 mm. 9.The method according to claim 3, wherein a vacuumizing port is arranged at the upper part or top of the tank body. 10.The method according to claim 9, wherein ​ ​ ​ ​ ​ The upper end of the polymer solution distributor is connected with the polymer solution inlet, and the other end is in contact with the surface of the spiral flow guide channel; and / or, The distance between the upper end of the spiral flow guide channel and the tangent of the vacuum port is ≥500mm.

11. The method according to one of claims 1 to 10, characterized in that The temperature difference of the heat medium entering and leaving the tank is ≤7℃.

12. The method of claim 11, wherein, The temperature difference of the heat medium entering and leaving the tank is ≤6℃.

13. The method of claim 11, wherein, The heat medium inlet communicates with the lower end of the internal channel of the spiral flow guide channel through a heat medium distributor.

14. The method of claim 13, wherein, The heat medium distributor includes one or more branch pipes, and when multiple branch pipes are included, the multiple branch pipes form a dendritic structure.

15. The method of claim 13, wherein, The heat medium outlet communicates with the internal flow channel of the spiral flow guide channel through a pipeline; and / or, The heat medium outlet is connected with the heat medium inlet through a circulation pipeline.

16. The method of claim 15, wherein, A booster device and a heat exchanger are arranged on the circulation pipeline.

17. The method of claim 1, wherein, In step (1), the polymer solution stream is introduced into the tank from the polymer solution inlet of the depolymerization device, and is sent into the surface flow channel of the spiral flow guide channel through the flow guide of one or more branch pipes; and / or, the heat medium stream is sent into the tank from the heat medium inlet of the depolymerization device, and is sent into the internal flow channel of the spiral flow guide channel through the flow guide of one or more branch pipes; and / or, In step (2), the polymer solution stream and the heat medium stream conduct heat through heat conduction, and the heat conduction is carried out on the spiral flow guide channel; and / or, In step (3), the heat medium outlet is introduced into the heat medium inlet after being treated by boosting and heat exchange in sequence.

18. The method of claim 17, wherein, The heat medium outlet is recycled back to the heat medium inlet after being heat exchanged to 72-100℃.

19. The method of claim 1, wherein, The specific heat capacity of the heat medium is ≥0.6 KJ / (Kg*K).

20. The method of claim 1, wherein, The specific heat capacity of the heat medium is ≥0.8 KJ / (Kg*K).

21. The method of claim 1, wherein, The operating pressure in the tank is 0.1-10KPaA.

22. The method of claim 1, wherein, The operating pressure in the tank is 0.5-6KPaA.

23. The method of claim 1, wherein, The operating pressure in the tank is 0.6-5KPaA.

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