A method and system for washing and purifying a polymer powder

Abstract

The application discloses a kind of polymer powder washing purification method and system, comprising the following steps: charging formation bed layer, bed layer depth liquid removal, steam penetration washing and bed layer drying.The application passes into washing liquid steam and hot gas in the same set of closed equipment in sequence, and continuously completes steam-driven deep liquid removal, steam penetration washing and hot air drying, completely gives up traditional mechanical separation and multiple material transfer steps, realizes the integration of from wet powder to dry powder, continuous processing, greatly simplifies the process, improves the efficiency of washing purification and the purity of product, reduces energy consumption.

Description

Technical Field

[0001] This invention relates to the field of polymer material synthesis and post-processing technology, and in particular to a method and system for washing and purifying polymer powders. Background Technology

[0002] High-performance polyaryletherketone (e.g., PEKC, PEEK) and polyarylethersulfone (e.g., PES, PPSU) resins are typically prepared via solution polycondensation. After polymerization, the reaction solution contains, in addition to the polymer, a large amount of solvent (e.g., DMAc, NMP, sulfolane, diphenyl sulfone), byproduct halide salts (e.g., NaCl, KF), and catalyst residues. Industrially, a common method is to add a precipitant (e.g., water, alcohol) to the polymerization solution to precipitate the polymer, forming a wet powder slurry.

[0003] Currently, traditional processes for separating and purifying polymers from this slurry often employ intermittent centrifuges or plate and frame filter presses for solid-liquid separation, followed by multiple "pulping-re-separation" operations on the filter cake using fresh detergent. For example, patent publication number CN119798663A discloses a purification method combining centrifugation, ultrasound, multi-stage centrifugation-washing, and leaching. Such processes suffer from significant drawbacks, including high equipment investment, lengthy processes, high energy consumption, cumbersome operation, high labor intensity, dust pollution, low washing efficiency (especially poor washing effect on impurities encapsulated in the micropores of polymer powder), and high solvent loss. These drawbacks have become a bottleneck restricting the improvement of quality and cost reduction, and the achievement of green and efficient production of such high-value polymers. Summary of the Invention

[0004] The purpose of this invention is to provide a technical solution for a washing and purification method and system for polymer powders, addressing the shortcomings of existing technologies. This washing and purification method involves sequentially introducing washing liquid steam and hot gas into the same closed equipment to continuously complete steam-driven deep dehydration, steam penetration washing, and hot air drying. It completely eliminates the traditional mechanical separation and multiple material transfer steps, realizing integrated and continuous processing from wet powder to dry powder, greatly simplifying the process, improving the efficiency of washing and purification and the purity of the product, and reducing energy consumption.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for washing and purifying polymer powder, characterized by comprising the following steps:

[0007] (a) Loading to form a bed: The wet polymer powder obtained after precipitation and draining of the polymerization reaction liquid is loaded into a container to form a powder bed;

[0008] (b) Bed dehydration: Washing liquid steam is introduced into the powder bed to raise the bed temperature to the boiling point of the washing liquid, which promotes the vaporization of the precipitant inside the powder and between the particles. The generated steam overflows from the powder bed and is discharged as waste liquid after condensation. The latent heat of the washing liquid steam is used to rapidly vaporize and carry out the liquid components such as precipitant and solvent in the micropores and gaps of the powder, thereby achieving efficient solid-liquid separation.

[0009] (c) Steam penetration washing: Washing liquid steam is continuously introduced into the powder bed after step (b) so that the steam penetrates the entire powder bed and washes the powder, while the washing liquid is discharged from the bottom of the powder bed; the washing liquid steam continuously penetrates the powder bed, and the trace liquid micro-rinsing effect generated by the condensation of the washing liquid steam is used to fully dissolve and wash away inorganic salts and residual solvents.

[0010] (d) Bed drying: Hot gas is introduced into the powder bed after washing in step (c) for forced air drying, and finally pure and dry polymer powder is obtained.

[0011] This washing and purification method involves sequentially introducing washing liquid steam and hot gas into the same closed equipment to continuously complete steam-driven deep dehydration, steam penetration washing, and hot air drying. It completely eliminates the traditional mechanical separation and multiple material transfer steps, realizing integrated and continuous processing from wet powder to dry powder. This greatly simplifies the process, improves the efficiency of washing and purification and the purity of the product, and reduces energy consumption.

[0012] Furthermore, between step (b) and step (c) there is also a bed wetting step: a low-temperature washing liquid is poured into the upper part of the powder bed, or supersaturated steam containing droplets is introduced to lower the temperature of the powder bed and form a liquid phase in the powder bed to pre-wet the powder.

[0013] Furthermore, the washing liquid vapor in steps (b) and (c) is at least one vapor selected from water, methanol, ethanol, or acetone.

[0014] Furthermore, the apparent flow rate of the washing liquid vapor in steps (b) and (c) is 0.1 to 1 m / s.

[0015] Furthermore, the hot gas in step (d) is hot air, hot nitrogen, or hot helium.

[0016] Furthermore, the temperature of the hot gas in step (d) is 120–200°C.

[0017] Furthermore, the apparent velocity of the hot gas in step (d) is 0.3–5 m / s.

[0018] Furthermore, the blower drying in step (d) continues until the volatile content in the polymer is below 2000 ppm.

[0019] Furthermore, the wet polymer in step (a) includes polyaryletherketone or polyarylethersulfone polymers.

[0020] Furthermore, polyaryletherketones include at least one of polyaryletherketones containing a phenolphthalein Cardo structure, polyaryletherketones containing a heteronaphthyl biphenyl structure, or polyetheretherketones.

[0021] Furthermore, polyarylethersulfone includes at least one of polysulfone, polyphenylsulfone, or polyethersulfone.

[0022] A system for implementing the washing and purification method of polymer powder as described above is characterized by comprising a washing device, a stirring mechanism rotatably connected within the washing device, a material inlet and a material outlet disposed on the washing device, a washing liquid inlet being provided on the material inlet, a filter screen for solid-liquid separation being provided at the bottom of the washing device near the material outlet, the filter screen being used to support the powder bed and for solid-liquid separation, a washing liquid outlet being provided at the bottom of the washing device below the filter screen, a gas-liquid separator being provided at the washing liquid outlet, and a hot gas inlet being provided at the bottom of the washing device between the filter screen and the gas-liquid separator.

[0023] This system integrates material, steam, hot air, and vapor-liquid separators, simplifying the structure. Process parameters are easy to monitor and control online, making it easy to achieve fully automated continuous or batch production and reducing labor intensity.

[0024] Furthermore, the washing device is a washing tower or a washing vessel.

[0025] Furthermore, the stirring mechanism includes a stirring shaft and near-wall stirring blades mounted on the stirring shaft. The outer edge of the near-wall stirring blades is close to the inner wall of the washing device to avoid channeling and sticking to the wall.

[0026] Furthermore, the near-wall stirring blades adopt a grid plate structure to achieve in-situ, gentle stirring of the bed at low speeds.

[0027] Furthermore, a powder filter screen is provided on the top of the washing device.

[0028] Furthermore, the mesh size of the filter screen is 0.3–3 mm.

[0029] Furthermore, the washing device is equipped with an insulation layer on the outside.

[0030] Furthermore, it also includes a temperature detection device and a pressure detection device installed inside the washing device, which are used to detect the temperature and pressure of the bed inside the washing device, respectively. The temperature detection device can be a temperature sensor, and the pressure detection device can be a pressure sensor.

[0031] The present invention, by adopting the above-described technical solution, has the following beneficial effects:

[0032] 1. The washing and purification method of the present invention continuously completes steam-driven deep dehydration, steam penetration washing and hot air drying by sequentially introducing washing liquid steam and hot gas in the same set of closed equipment. It completely eliminates the traditional mechanical separation and multiple material transfer steps, realizes integrated and continuous processing from wet powder to dry powder, greatly simplifies the process, improves the efficiency of washing and purification and the purity of the product, and reduces energy consumption.

[0033] 2. Steam can penetrate the micropores of powders that are difficult for traditional liquid phases to reach, and combined with stirring to avoid channeling, it achieves deep and uniform washing. Inorganic salt and solvent residues in the product can be reduced to extremely low levels, improving washing efficiency and product purity.

[0034] 3. Fully utilize the latent heat of steam for heating and mass transfer, resulting in high thermal energy utilization. The washing liquid can be condensed, recovered, and recycled, reducing losses and saving 30% to 50% of water compared to traditional processes.

[0035] 4. The entire process is carried out in a closed system, with no dust leakage, no material conveying loss, and a clean and safe working environment.

[0036] 5. This system integrates materials, steam, hot air, and vapor-liquid separators, simplifying the structure and integrating multiple devices and intermittent steps into continuous operation of a single device. The number of devices and floor space are reduced by more than 60%, significantly reducing investment and operating costs. At the same time, process parameters are easy to monitor and control online, making it easy to achieve fully automated continuous or batch production and reducing labor intensity. Attached Figure Description

[0037] The present invention will be further described below with reference to the accompanying drawings:

[0038] Figure 1 This is a flowchart of a washing and purification method for polymer powder and a system thereof, according to the present invention.

[0039] Figure 2 This is a schematic diagram of the washing and purification system in this invention.

[0040] In the diagram: 1-washing device; 2-near-wall stirring blade; 3-stirring shaft; 4-material inlet; 5-material outlet; 6-washing liquid inlet; 7-washing liquid outlet; 8-filter screen; 9-gas-liquid separator; 10-hot gas inlet; 11-powder filter screen. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0044] like Figure 1 The figure shows a method for washing and purifying polymer powder according to the present invention, comprising the following steps:

[0045] (a) Loading to form a bed: The wet polymer powder obtained after precipitation and draining of the polymerization reaction liquid is loaded into a container to form a powder bed;

[0046] (b) Bed dehydration: Washing liquid steam is introduced into the powder bed to raise the bed temperature to the boiling point of the washing liquid, which promotes the vaporization of the precipitant inside the powder and between the particles. The generated steam overflows from the powder bed and is discharged as waste liquid after condensation. The latent heat of the washing liquid steam is used to rapidly vaporize and carry out the liquid components such as precipitant and solvent in the micropores and gaps of the powder, thereby achieving efficient solid-liquid separation.

[0047] The washing liquid vapor is at least one of water, methanol, ethanol or acetone.

[0048] The apparent velocity of the washing liquid vapor is 0.1–1 m / s.

[0049] It also includes a bed impregnation step: spraying a low-temperature washing liquid onto the upper part of the powder bed, or introducing supersaturated steam containing droplets, so as to lower the temperature of the powder bed and form a liquid phase in the powder bed to pre-impregnate the powder.

[0050] (c) Steam penetration washing: Washing liquid steam is continuously introduced into the powder bed after step (b) so that the steam penetrates the entire powder bed and washes the powder, while the washing liquid is discharged from the bottom of the powder bed; the washing liquid steam continuously penetrates the powder bed, and the trace liquid micro-rinsing effect generated by the condensation of the washing liquid steam is used to fully dissolve and wash away inorganic salts and residual solvents.

[0051] The washing liquid vapor is at least one of water, methanol, ethanol or acetone.

[0052] The apparent velocity of the washing liquid vapor is 0.1–1 m / s.

[0053] (d) Bed drying: Hot gas is introduced into the powder bed after washing in step (c) for forced air drying, and finally pure and dry polymer powder is obtained.

[0054] The hot gas is hot air, hot nitrogen, or hot helium.

[0055] The temperature of the hot gas is 120–200℃.

[0056] The apparent velocity of the hot gas is 0.3–5 m / s.

[0057] Blow-drying continues until the volatile content in the polymer is below 2000 ppm.

[0058] The polymers include polyaryletherketone or polyarylethersulfone polymers.

[0059] Polyaryletherketones include at least one of polyaryletherketones containing a phenolphthalein Cardo structure, polyaryletherketones containing a heteronaphthyl biphenyl structure, or polyetheretherketones.

[0060] Polyarylethersulfone includes at least one of polysulfone, polyphenylsulfone, or polyethersulfone.

[0061] This washing and purification method involves sequentially introducing washing liquid steam and hot gas into the same closed equipment to continuously complete steam-driven deep dehydration, steam penetration washing, and hot air drying. It completely eliminates the traditional mechanical separation and multiple material transfer steps, realizing integrated and continuous processing from wet powder to dry powder. This greatly simplifies the process, improves the efficiency of washing and purification and the purity of the product, and reduces energy consumption.

[0062] like Figure 2 As shown, this invention provides a system for implementing the washing and purification method for polymer powder as described above, comprising a washing device 1, a stirring mechanism rotatably connected within the washing device 1, a material inlet 4 and a material outlet 5 provided on the washing device 1.

[0063] Washing device 1 is a washing tower or washing vessel.

[0064] The stirring mechanism includes a stirring shaft 3 and near-wall stirring blades 2 mounted on the stirring shaft 3. The outer edge of the near-wall stirring blades 2 is close to the inner wall of the washing device 1 to avoid channeling and wall adhesion. The near-wall stirring blades 2 adopt a grid plate structure to achieve in-situ and gentle stirring of the bed at low speed.

[0065] The material inlet 4 is equipped with a washing liquid inlet 6.

[0066] The washing device 1 is equipped with a powder filter screen 11 at the top.

[0067] The washing device 1 is provided with an insulation layer on the outside.

[0068] The bottom of the washing device 1, near the material outlet 5, is equipped with a filter screen 8 for solid-liquid separation. The filter screen 8 supports the powder bed and facilitates solid-liquid separation. The mesh size of the filter screen 8 is 0.3–3 mm.

[0069] The washing device 1 has a washing liquid outlet 7 located below the filter screen 8 at its bottom. The washing liquid outlet 7 is equipped with a vapor-liquid separator 9. The washing device 1 also has a hot gas inlet 10 located between the filter screen 8 and the vapor-liquid separator 9 at its bottom.

[0070] This system integrates nine components, including material, steam, hot air, and vapor-liquid separators, simplifying the structure. Process parameters are easy to monitor and control online, facilitating fully automated continuous or batch production and reducing labor intensity.

[0071] It also includes a temperature detection device and a pressure detection device installed in the washing device 1, which are used to detect the temperature and pressure of the bed inside the washing device 1, respectively. The temperature detection device can be a temperature sensor, and the pressure detection device can be a pressure sensor.

[0072] Example 1: Washing and purification of PEKC resin

[0073] 1. System Configuration: Adopting as follows Figure 2 The system shown has a washing tower with an inner diameter of 2.0 meters and an effective height of 4 meters, and is equipped with an external insulation layer. The bottom filter screen has a mesh size of 0.6 mm. The stirring mechanism consists of two-layer mesh plate near-wall stirring blades with an opening rate of approximately 85% and an 8 mm gap between the outer edge and the tower wall. It is driven by a top motor with a rotation speed controlled at 10 rpm.

[0074] 2. Raw materials: Phenolphthalein polyarylether ketone (PEKC) wet powder, obtained by precipitation and draining of sulfolane solution in water, with a water content of about 280% (relative to polymer mass), a sulfolane content of about 40% (equivalent to polymer mass), and a KF and salt content of about 0.5%.

[0075] 3. Process steps and parameters:

[0076] Loading: Approximately 900 kg of wet powder is fed into the washing tower through the material inlet to form a fixed bed layer with a height of approximately 0.5 m.

[0077] Deep desliming: Close the inlet and outlet ports, and introduce saturated steam at 0.1 MPa (gauge pressure) into the washing liquid inlet. The steam heats the bed, causing the water and sulfolane in the powder voids to vaporize. The mixed steam is then piped from the top of the washing tower to the condenser for condensation and recovery. This process lasts approximately 30 minutes until the temperature at the bottom of the bed stabilizes at 100°C.

[0078] Steam penetration washing: Saturated steam is continuously introduced, maintaining a slightly positive pressure within the washing tower, with an apparent steam velocity of approximately 0.3 m / s. The steam partially condenses as it penetrates the bed, washing the powder. The washing condensate is separated by a bottom filter and discharged from the washing liquid outlet. The conductivity of the discharged liquid is monitored online. The washing process takes approximately 2 hours. Washing is considered successful when the conductivity of the discharged liquid stably drops below 50 μS / cm (approximately equivalent to a total dissolved solids (TDS) of 30 ppm).

[0079] Hot air drying: Stop steam supply and instead introduce hot nitrogen gas at 180℃ through the hot gas inlet at an apparent velocity of approximately 3.0 m / s to dry the bed. The wet nitrogen gas is discharged through the top powder filter. The drying process takes about 2.5 hours. The drying is stopped when the moisture content of the polymer powder is below 0.1%, as determined by monitoring the exhaust dew point or using an online moisture meter.

[0080] Discharge: Open the side material outlet to obtain dry PEKC powder.

[0081] 4. Results: The obtained PEKC powder is white, with extremely low ash content and stable intrinsic viscosity. Testing showed that the residual ash content was less than 30 ppm and the residual sulfolane content was less than 200 ppm.

[0082] Comparative Example 1 (Conventional process for processing the same batch of PEKC wet powder)

[0083] The same wet powder was filtered using a plate and frame filter press to obtain a filter cake. The filter cake was transferred to a washing vessel, and water of the same mass as the wet powder was added. The mixture was heated to boiling, slurried, and washed for 1 hour, followed by another filtration. This slurrying-filtration step was repeated three times. Finally, the filter cake was dried in a vacuum oven at 180℃ for 24 hours.

[0084] Results Comparison: The traditional process takes approximately 30 hours and consumes about four times the mass of the powder. The resulting product has a residual salt ash content of approximately 100 ppm and a residual sulfolane content of approximately 3000 ppm.

[0085] Example 2: Washing and purification of polyethersulfone (PES) resin

[0086] The same system and operating procedure as in Example 1 were used to process the PES wet powder obtained with sulfolane as solvent and water as precipitant. The main process parameters were adjusted as follows: During the steam washing stage, the apparent steam flow rate was controlled at 0.2 m / s, and the washing time was 2.5 hours. During the hot air drying stage, the hot air temperature was set at 160°C, and the drying time was 4 hours.

[0087] Results: The obtained PES powder had a pure color, with residual inorganic salt content of less than 40 ppm and residual sulfolane content of less than 150 ppm. The total processing time was shortened by approximately 60% compared to the traditional multiple pulping-drying process.

[0088] Comparative Example 2 (PES wet powder of the same batch treated by conventional process)

[0089] The same traditional pulping-pressing-drying process as Comparative Example 1 was used.

[0090] Results: The product was slightly grayish in color, with a residual sulfolane content of about 0.3%, and the powder showed signs of clumping after drying.

[0091] Summary of optimal ranges for system parameters (based on the results of the implementation examples):

[0092] Equipment dimensions: The height of the internal space of the washing tower or washing tank is preferably 3 to 6 meters, and the thickness of the loading bed is preferably 0.5 to 2 meters.

[0093] Mixing mechanism: The near-wall mixing blades should preferably be made of mesh plates with an open area ratio greater than 70%. The mixing speed should preferably be below 20 rpm, preferably 5 to 15 rpm, to achieve gentle mixing and avoid powder breakage.

[0094] Filter screen: The preferred mesh size of the filter screen is 0.3 to 3 mm. It should match the particle size of the powder and be easy to disassemble and replace.

[0095] Washing process: The apparent flow rate of washing steam (water, alcohol, acetone or a mixture thereof) is preferably 0.1 to 0.4 m / s. The washing endpoint can be determined by the conductivity of the discharged liquid, preferably reduced to below 500 μS / cm, more preferably reduced to below 50 μS / cm (about 30 ppm TDS).

[0096] Drying process: The preferred temperature of the hot gas (air, nitrogen) is 120–180°C, and the preferred apparent flow rate is 1–2 m / s. The drying endpoint is when the volatile content in the polymer is below 1000 ppm, preferably below 500 ppm.

[0097] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to achieve substantially the same technical effect are all covered within the protection scope of the present invention.

Claims

1. A method for washing and purifying polymer powder, characterized in that... Includes the following steps: (a) Packing to form a bed: The wet polymer powder obtained after the polymerization reaction liquid is precipitated and drained is packed into a container to form a powder bed; (b) Bed dehydration: Washing liquid steam is introduced into the powder bed to raise the bed temperature to the boiling point of the washing liquid, which promotes the vaporization of the precipitant inside the powder and between the particles. The generated steam overflows from the powder bed and is discharged as waste liquid after condensation. (c) Steam penetration washing: Washing liquid steam is continuously introduced into the powder bed after step (b) so that the steam penetrates the entire powder bed and washes the powder, while the washing liquid is discharged from the bottom of the powder bed. (d) Bed drying: Hot gas is introduced into the powder bed after washing in step (c) for forced air drying, and finally pure and dry polymer powder is obtained.

2. The method for washing and purifying polymer powder according to claim 1, characterized in that: Between step (b) and step (c), there is also a bed impregnation step: a low-temperature washing liquid is poured into the upper part of the powder bed, or supersaturated steam containing droplets is introduced to lower the temperature of the powder bed and form a liquid phase in the powder bed to pre-impregnate the powder.

3. The method for washing and purifying polymer powder according to claim 1, characterized in that: The washing liquid vapor in steps (b) and (c) is at least one of water, methanol, ethanol or acetone.

4. The method for washing and purifying polymer powder according to claim 1, characterized in that: The apparent flow rate of the washing liquid vapor in steps (b) and (c) is 0.1 to 1 m / s.

5. The method for washing and purifying polymer powder according to claim 1, characterized in that: The hot gas in step (d) is hot air, hot nitrogen, or hot helium.

6. The method for washing and purifying polymer powder according to claim 1, characterized in that: The temperature of the hot gas in step (d) is 120–200°C.

7. The method for washing and purifying polymer powder according to claim 1, characterized in that: The apparent velocity of the hot gas in step (d) is 0.3 to 5 m / s.

8. The method for washing and purifying polymer powder according to claim 1, characterized in that: The blower drying in step (d) continues until the volatile content in the polymer is below 2000 ppm.

9. The method for washing and purifying polymer powder according to claim 1, characterized in that: The wet polymer in step (a) includes polyaryletherketone or polyarylethersulfone polymers.

10. The method for washing and purifying polymer powder according to claim 9, characterized in that: The polyaryletherketone includes at least one of polyaryletherketone containing a phenolphthalein Cardo structure, polyaryletherketone containing a heteronaphthyl biphenyl structure, or polyetheretherketone.

11. The method for washing and purifying polymer powder according to claim 9, characterized in that: The polyarylethersulfone includes at least one of polysulfone, polyphenylsulfone, or polyethersulfone.

12. A system for implementing the washing and purification method for polymer powders as described in any one of claims 1 to 11, characterized in that: The device includes a washing apparatus, a stirring mechanism rotatably connected within the washing apparatus, a material inlet and a material outlet on the washing apparatus. The material inlet has a washing liquid inlet. The bottom of the washing apparatus near the material outlet has a filter screen for solid-liquid separation. The bottom of the washing apparatus, below the filter screen, has a washing liquid outlet. The washing liquid outlet has a vapor-liquid separator. The bottom of the washing apparatus, between the filter screen and the vapor-liquid separator, has a hot gas inlet.

13. The polymer powder washing and purification system according to claim 12, characterized in that: The washing device is a washing tower or a washing kettle.

14. The polymer powder washing and purification system according to claim 12, characterized in that: The stirring mechanism includes a stirring shaft and near-wall stirring blades mounted on the stirring shaft, with the outer edge of the near-wall stirring blades close to the inner wall of the washing device.

15. The polymer powder washing and purification system according to claim 14, characterized in that: The near-wall stirring blades adopt a grid plate structure.

16. The polymer powder washing and purification system according to claim 12, characterized in that: The washing device is equipped with a powder filter screen at the top.

17. The polymer powder washing and purification system according to claim 12, characterized in that: The mesh size of the filter screen is 0.3 to 3 mm.

18. The polymer powder washing and purification system according to claim 12, characterized in that: The washing device is equipped with an external heat insulation layer.

19. A washing and purification system for polymer powder according to claim 12, characterized in that: It also includes a temperature detection device and a pressure detection device installed inside the washing device, which are used to detect the temperature and pressure of the bed inside the washing device, respectively.

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