Resin particle dedusting device, resin particle dedusting system and method

Abstract

The application relates to the field of ethylene-vinyl alcohol copolymer production and processing, and discloses a resin particle powder removing device, a resin particle powder removing system and a method. The resin particle powder removing device comprises a resin particle powder removing device body, a filter plate is arranged in the resin particle powder removing device body, the included angle between the filter plate and the horizontal direction is 1.1-2 times of the rest angle of the resin particle, and the pore diameter of the filter plate is 0.2-0.8 times of the average particle diameter of the resin particle. The resin particle powder removing device effectively reduces the content of powder in ethylene-vinyl alcohol copolymer resin particles and improves product quality.

Description

Technical Field

[0001] This invention relates to the field of ethylene-vinyl alcohol copolymer production and processing technology, specifically to a resin particle dust removal device, resin particle dust removal system and method. Background Technology

[0002] Ethylene-vinyl alcohol copolymer (EVOH) is a novel polymeric synthetic material that combines the processability of ethylene polymers with the gas barrier properties of vinyl alcohol polymers. It possesses excellent gas barrier properties, water resistance, oil resistance, and ammonia barrier properties. EVOH, along with polyvinylidene chloride (PVDC) and polyamide (PA), is considered one of the world's three major high-barrier resins. In the 1950s, DuPont first produced EVOH resin through copolymerization and alcoholysis of ethylene and vinyl acetate (VAc).

[0003] In existing EVOH production processes, EVOH is generally produced by polymerizing ethylene and vinyl acetate using conventional methods such as emulsion polymerization, solution polymerization, or suspension polymerization, followed by saponification. In solution polymerization, an alcohol with no more than four carbon atoms is typically used as the solvent (methanol is preferred). The resulting ethylene-vinyl acetate copolymer solution contains the solvent methanol and unreacted vinyl acetate monomer. Utilizing the azeotropic properties of methanol and vinyl acetate, the unreacted vinyl acetate is removed in a distillation column by adding methanol solution or blowing in methanol vapor. The solution then enters an alcoholysis unit, where methyl acetate is removed by distillation, yielding EVOH with a degree of alcoholysis of over 99% at the bottom.

[0004] The alcoholysis of EVOH can be carried out using a batch alcoholysis method. CN104098733A discloses an alcoholysis method for ethylene-vinyl acetate copolymer, in which alcoholysis is carried out under conditions of -4 to 0 atmospheres, reaction temperature of 40-85℃, and reaction time of 4-7 hours, followed by neutralization and washing to obtain EVOH product. The main problems of this method are long alcoholysis reaction time and low production efficiency.

[0005] The alcoholysis of EVOH can also be carried out using a tower-type alcoholysis. CN1196724C discloses a method for producing ethylene-vinyl acetate copolymer saponified products, which uses a tower-type saponification reactor. The ethylene-vinyl acetate copolymer is added from the top of the tower, the catalyst alkali solution is added from the top and middle of the tower, and a small amount of water is added to control product quality.

[0006] The catalysts used for the alcoholysis of EVOH are usually methanol solutions containing sodium hydroxide or potassium hydroxide. CN115433301A discloses the use of an acidic deep eutectic solvent of choline chloride-p-toluenesulfonic acid for alcoholysis, which can effectively reduce the problem of metal ions affecting product quality when using sodium hydroxide, and the solvent can be recycled multiple times. However, no specific method for solvent recovery is mentioned.

[0007] The EVOH resin obtained through alcoholysis is molded and dried to obtain EVOH products. During the molding and pelletizing process, the sharp edges of the resin particles and the tail material of the pellets are worn off after drying, and the powder is generated from the wear of the sharp edges and the fall of the tail material. In addition, a small amount of powder is generated and adheres to the product during product conveying and handling. When the powder in the resin is used downstream in EVOH, it adheres to the surface of the extruder inner cylinder and deteriorates over a long period of time, forming gel impurities, which affect the appearance and performance of the final product.

[0008] Therefore, there is an urgent need to develop a method for removing powder from ethylene-vinyl alcohol copolymers in order to reduce the dust content in EVOH products. Summary of the Invention

[0009] The purpose of this invention is to overcome the problems in the existing technology of ethylene-vinyl alcohol copolymer production, such as the sharp edges of the ethylene-vinyl alcohol copolymer particles and the powdering of granulated tail material during drying. This invention provides a resin particle powder removal device, system, and method. The resin particle powder removal device of this invention effectively reduces the powder content in ethylene-vinyl alcohol copolymer resin particles, thereby improving product quality.

[0010] To achieve the above objectives, the first aspect of the present invention provides a resin particle dust removal device, wherein a filter plate is disposed inside the main body of the resin particle dust removal device, the angle between the filter plate and the horizontal direction is 1.1-2 times the angle of repose of the resin particles, and the pore size of the filter plate is 0.2-0.8 times the average particle size of the resin particles.

[0011] A second aspect of the present invention provides a resin particle dust removal system, the system comprising: the resin particle dust removal device described in the first aspect, an air supply unit, and an exhaust unit; the air supply unit is connected to the air inlet of the resin particle dust removal device via an air inlet pipeline 103, and the exhaust unit is connected to the air outlet of the resin particle dust removal device via an air outlet pipeline 104.

[0012] A third aspect of the present invention provides a method for removing resin particles, the method being performed in the resin particle removal system described in the second aspect above, the method comprising:

[0013] Resin particles are added to a resin particle dust removal device for dust removal, resulting in a mixture of dust-removed resin particles and dust-containing gas.

[0014] Through the above technical solution, the present invention has the following beneficial effects:

[0015] The resin particle dust removal device provided by this invention has a filter plate installed inside the device body. By controlling the relationship between the angle between the filter plate and the horizontal direction and the angle of repose of the resin particles, the falling speed of the resin particles can be controlled. By controlling the relationship between the pore size of the filter plate and the average particle size of the resin particles, not only are the resin particles allowed to pass through the filter plate without falling into the pores, but airflow is also allowed to pass through and contact the resin particles with a specific falling speed. This achieves effective removal of powder from ethylene-vinyl alcohol copolymer resin particles, and is especially suitable for removing fine powder with a particle size of less than 100 μm. It reduces powder residue on the particle surface, and the whole process is simple and convenient with high dust removal efficiency. It reduces equipment failure, product appearance defects, and performance degradation caused by powder in downstream processing, improves the overall quality of the product, and indirectly reduces production costs. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.

[0017] Figure 1 This is a schematic diagram of the resin particle dust removal system described in this invention.

[0018] Explanation of reference numerals in the attached figures

[0019] 1. Resin dust removal device body; 2. Filter plate; 3. Air intake unit

[0020] 4. Exhaust unit; 5. Filter unit; 101. Feed line

[0021] 102 Discharge pipeline 103 Inlet pipeline 104 Outlet pipeline

[0022] 105 De-powdering gas pipeline; 106 Powder outlet pipeline Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] The first aspect of the present invention provides a resin particle dust removal device, wherein a filter plate is disposed inside the main body of the resin particle dust removal device, the angle between the filter plate and the horizontal direction is 1.1-2 times the angle of repose of the resin particles, and the pore size of the filter plate is 0.2-0.8 times the average particle size of the resin particles.

[0025] During the research process, the inventors of this invention discovered that by setting a filter plate inside the main body of the resin particle dust removal device, and controlling the relationship between the angle between the filter plate and the horizontal direction and the angle of repose of the resin particles, the falling speed of the resin particles can be controlled. By controlling the relationship between the aperture of the filter plate and the average particle size of the resin particles, the resin particles can pass through the filter plate without falling into the holes. At the same time, the airflow passes through the holes of the filter plate from bottom to top and contacts the resin particles with a specific falling speed, thereby capturing and carrying away the powder on the surface of the resin particles, achieving effective powder removal, significantly reducing the powder content in the obtained dust-removed resin particle product, having high dust removal efficiency, and improving the overall quality of the dust-removed resin particle product.

[0026] In this invention, unless otherwise specified, the resin particles refer to the resin particles obtained by alcoholysis in the prior art, which are then subjected to extrusion molding, granulation, washing and drying to obtain resin particle products. Preferably, the resin particle products refer to EVOH resin particle products.

[0027] In some embodiments of the present invention, preferably, the included angle of the filter plate in the horizontal direction is 1.1-2 times the angle of repose of the resin particles. For example, it can be 1.1 times, 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2 times, or any value within the range of the two values ​​mentioned above.

[0028] In this invention, the included angle of the filter plate in the horizontal direction is greater than the angle of repose of the resin particles. Controlling the relationship between the included angle of the filter plate in the horizontal direction and the angle of repose of the resin particles within the aforementioned range helps to balance the falling speed of the resin particles and the dust removal effect, ensuring that the resin particles have sufficient contact time with the filter plate when passing through it, so that the powder adhering to the surface of the resin particles is effectively removed. If the included angle of the filter plate in the horizontal direction is less than 1.1 times the angle of repose of the resin particles, the resin particles accumulate on the filter plate, resulting in a decrease in the dust removal effect and affecting the continuity and efficiency of the production process. If the included angle of the filter plate in the horizontal direction is greater than 2 times the angle of repose of the resin particles, the material falls too fast, and the powder is carried away before it can fully contact and separate from the filter plate, reducing the dust removal effect.

[0029] Preferably, the angle between the filter plate and the horizontal direction is 1.2-1.6 times the angle of repose of the resin particles.

[0030] In this invention, when multiple filter plates are present, the angle between each filter plate and the horizontal direction can be the same or different, as long as the angle between each filter plate and the horizontal direction and the angle of repose of the resin particles satisfy the above-mentioned relationship. Preferably, when multiple filter plates are present, the angle between each filter plate and the horizontal direction is the same.

[0031] In this invention, the method for testing the angle of repose of the resin particles includes: adding the resin particles from the top of the angle of repose detector and allowing them to fall naturally into the receiving tray; when the material area reaches 15 cm², the particle size distribution is determined. 2 At that time, the angle of material accumulation was detected, and the detection was repeated 3 times and the average value was taken.

[0032] In some embodiments of the present invention, preferably, the pore size of the filter plate is 0.2-0.8 times the average particle size of the resin particles, for example, it can be 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times, 0.8 times, or any value within the range of the two values ​​mentioned above.

[0033] In this invention, unless otherwise specified, the pore size of each hole on the filter plate is the same. There is no particular limitation on the pore size of the filter plate, as long as the pore size of the filter plate and the average particle size of the resin particles satisfy the above-mentioned relationship.

[0034] In this invention, controlling the relationship between the pore size of the filter plate and the average particle size of the resin particles within the aforementioned range, in conjunction with the angle between the filter plate and the horizontal direction and the angle of repose of the resin particles, facilitates efficient powder removal when the resin particles pass through the filter plate, while preventing clogging or powder re-adhesion. This significantly reduces the powder content in the EVOH product and promotes uniform airflow distribution, allowing the airflow to more effectively contact the resin particles and carry away the powder. If the pore size of the filter plate is less than 0.2 times the average particle size of the resin particles, the powder removal effect is poor, leading to powder re-adhesion or incomplete separation. If the pore size of the filter plate is greater than 0.8 times the particle size of the resin particles, powder may pass through the filter plate with the resin particles, reducing the powder removal efficiency.

[0035] Preferably, the pore size of the filter plate is 0.3-0.6 times the average particle size of the resin particles.

[0036] In this invention, the average particle size of the resin particles is measured using a laser particle size analyzer.

[0037] In this invention, the number of filter plates is closely related to the powder content in the resin particles. Preferably, when the powder content in the resin particles is less than 10 mg / kg, the number of filter plates is 1-4 layers; when the powder content in the resin particles is 10-50 mg / kg, the number of filter plates is 2-6 layers; and when the powder content in the resin particles is greater than 50 mg / kg, the number of filter plates is 2-8 layers. More preferably, when the powder content in the resin particles is less than 10 mg / kg, the number of filter plates is 2-3 layers; when the powder content in the resin particles is 10-50 mg / kg, the number of filter plates is 3-5 layers; and when the powder content in the resin particles is greater than 50 mg / kg, the number of filter plates is 3-6 layers.

[0038] In this invention, the number of filter plates is set within the range described above when the powder content in the resin particles is within the aforementioned range. This is beneficial for reducing costs while ensuring both powder removal effect and efficiency. A preferred range of filter plate layers further facilitates cost reduction.

[0039] In this invention, there are no particular limitations on the arrangement of adjacent filter layers, as long as the two layers are not parallel and the resin particles can flow from top to bottom on each filter layer in sequence. Preferably, the included angle between adjacent filter layers is 10-50°, more preferably 20-40°.

[0040] In this invention, the angle between each of the two adjacent filter layers and the horizontal direction can be the same or different. Preferably, the angle between each of the two adjacent filter layers and the horizontal direction is the same.

[0041] In this invention, the method for testing the powder content in the resin particles includes: sieving with a grading sieve, weighing 200 grams (w1) of resin particle sample, sieving with a 100-mesh grading sieve, and weighing the weight of the fine particles after sieving (w2). The powder content of the resin particles is then w2 / w1×100000 (mg / kg).

[0042] In this invention, the area of ​​the filter plate is closely related to the powder content in the resin particles. Preferably, when the powder content in the resin particles is less than 10 mg / kg, the area of ​​the filter plate is 100-300 cm². 2 When the powder content in the resin particles is 10-50 mg / kg, the area of ​​the filter plate is 200-500 cm². 2 When the powder content in the resin particles is greater than 50 mg / kg, the area of ​​the filter plate is 300-600 cm². 2More preferably, when the powder content in the resin particles is less than 10 mg / kg, the area of ​​the filter plate is 120-250 cm². 2 When the powder content in the resin particles is 10-50 mg / kg, the area of ​​the filter plate is 300-400 cm². 2 When the powder content in the resin particles is greater than 50 mg / kg, the area of ​​the filter plate is 400-500 cm². 2 .

[0043] In this invention, the area of ​​the filter plate is set within the range described above when the powder content in the resin particles is within the aforementioned range. This is beneficial for reducing costs while ensuring powder removal effect and efficiency. Further cost reduction is achieved within the preferred range of filter plate layers.

[0044] In this invention, unless otherwise specified, the area of ​​the filter plate refers to the area of ​​one layer of filter plate. The area of ​​each layer of filter plate in this invention can be the same or different. Preferably, the area of ​​each layer of filter plate is the same. In this invention, preferably, the total area of ​​the holes in each layer of filter plate accounts for 30-80% of the total area of ​​each layer of filter plate. The holes in each layer of filter plate in this invention can be uniformly distributed or randomly distributed, as long as the hole diameter and the total area of ​​the holes in each layer of filter plate meet the aforementioned range. Preferably, the holes are uniformly distributed.

[0045] In this invention, the area of ​​the filter plate is closely related to the flow rate of the resin particles. Based on the powder content in the resin particles meeting the aforementioned range, preferably, the area of ​​the filter plate is 150-600 cm² relative to a resin particle flow rate of 500 kg / h. 2 Preferably 200-500cm 2 In this invention, controlling the powder content in the resin particles, the area of ​​the filter plate, and the flow rate of the resin particles simultaneously within the aforementioned ranges is more conducive to improving the powder removal effect and efficiency.

[0046] In some embodiments of the present invention, preferably, a feed inlet is provided at the top of the resin particle dust removal device body, and the feed inlet is connected to the feed pipeline 101. In the present invention, resin particles enter the resin particle dust removal device body from the feed inlet through the feed pipeline 101.

[0047] In some embodiments of the present invention, preferably, the bottom of the resin particle de-dusting device body is provided with a discharge port, which is connected to the discharge pipeline 102. In the present invention, the resin particles fed from the top of the resin particle de-dusting device body are de-dusted by the filter plate, and the resulting de-dusted resin particle product enters the 102 pipeline through the discharge port at the bottom of the resin particle de-dusting device body and then enters the product silo.

[0048] In some embodiments of the present invention, preferably, an air inlet is provided at the bottom of the resin particle dust removal device body near the discharge port area, for introducing gas from the bottom of the resin particle dust removal device body into the interior of the resin particle dust removal device body. In the present invention, the gas is introduced into the interior from the air inlet at the bottom of the resin particle dust removal device body, and the gas flows from bottom to top. The airflow formed by the filter plate directly acts on the surface of the resin particles, which is beneficial for peeling off and dispersing the adhered powder. Furthermore, the gas flow can carry away the peeled powder, preventing it from accumulating inside the device and maintaining the cleanliness and dust removal efficiency of the device interior.

[0049] In some embodiments of the present invention, preferably, an air outlet is provided at the top of the resin particle dust removal device body near the feed inlet area, for discharging the gas introduced from the bottom out of the resin particle dust removal device body. In the present invention, the dust carried away by the gas flow forms a dust-containing gas mixture, which is discharged from the resin particle dust removal device body through the air outlet.

[0050] In some embodiments of the present invention, preferably, a sealing device is provided at the tail end of the filter plate to prevent lower-layer gas from directly entering the upper layer without passing through the filter plate. In this invention, the sealing device is located at the tail end of each filter plate, connected to the tail end of each filter plate and oriented downwards, and does not contact the inner wall of the resin particle removal device body or the next layer of filter plate. The distance between the sealing device and the inner wall of the resin particle removal device body and the next layer of filter plate is not particularly limited; those skilled in the art can choose according to actual circumstances.

[0051] In this invention, the resin particle de-powdering device is suitable for removing powder of various particle sizes from resin particles, especially for removing fine powder particles. Preferably, the fine powder particles refer to powder with an average particle size of less than 100 μm.

[0052] A second aspect of the present invention provides a resin particle dust removal system, the system comprising: the resin particle dust removal device described in the first aspect, an air supply unit, and an exhaust unit; the air supply unit is connected to the air inlet of the resin particle dust removal device via an air inlet pipeline 103, and the exhaust unit is connected to the air outlet of the resin particle dust removal device via an air outlet pipeline 104.

[0053] In this invention, the resin particle dust removal system includes the aforementioned resin particle dust removal device, air supply unit, and exhaust unit. The resin particle dust removal device possesses all the features and advantages of the aforementioned resin particle dust removal device, effectively removing powder from resin particles, especially fine powder particles with a particle size of less than 100μm. The dust removal effect is more significant, greatly improving the overall quality of EVOH resin products and meeting the demand of downstream users for high-quality resin products. Furthermore, the entire process is simple, has high production efficiency, and low cost.

[0054] In this invention, the air supply unit can be any device conventionally used in the art capable of supplying air, preferably a blower. In this invention, the air supply unit is used to deliver gas from the air inlet through the air inlet pipe 103 into the interior of the resin particle dust removal device.

[0055] In this invention, the exhaust unit can be any device conventionally used in the art for exhausting gases, preferably an exhaust fan. In this invention, the exhaust unit is used to discharge a dust-laden gas mixture formed by dust carried by the gas flow through the exhaust pipe 104.

[0056] In some embodiments of the present invention, preferably, the system further includes a filtration unit connected to the exhaust unit. In this invention, the filtration unit is used to filter the powder-containing gas mixture discharged from the exhaust unit, thereby separating the powder and the de-powdering gas. In some embodiments of the present invention, preferably, the air outlet at the top of the filtration unit is connected to the de-powdering gas pipeline 105; the powder outlet at the bottom of the filtration unit is connected to the powder outlet pipeline 106. In this invention, the powder separated by the filtration unit enters the powder outlet pipeline 106 for collection, and the de-powdering gas separated by the filtration unit enters the de-powdering gas pipeline 105 for discharge.

[0057] In this invention, the filtration unit can be a device conventionally used in the art for separating mixed gases and solid powders, for example, a filter. The number of filters in this invention is not particularly limited, but two units are preferred. In this invention, the intermittent removal of dust by using one unit in operation and one in standby mode helps maintain production continuity.

[0058] In this invention, the pore size of the filter bag in the filtration unit is not particularly limited, and those skilled in the art can select it according to the size of the powder in the resin particles to be removed. Preferably, the pore size of the filter bag in the filtration unit is 20-200 mesh.

[0059] A third aspect of the present invention provides a method for removing resin particles, wherein the method is performed in the resin particle removal system described in the second aspect above, and the method includes:

[0060] Resin particles are added to a resin particle dust removal device for dust removal, resulting in a mixture of dust-removed resin particles and dust-containing gas.

[0061] In this invention, the resin particle powder removal method can effectively remove powder from EVOH resin products, especially fine powder particles with a particle size of less than 100μm. The powder removal effect is more significant, which helps to improve the overall quality of the product, meets the demand of downstream users for high-quality products, and the whole process is simple, efficient and low-cost.

[0062] In some embodiments of the present invention, preferably, the method further includes: simultaneously introducing gas from the bottom of the resin particle dust removal device while adding the resin particles. In the present invention, the airflow formed by the gas passing through the filter plate holes can directly act on the surface of the resin particles, which is beneficial for peeling off and dispersing the adhered powder. The gas flow carries away the peeled powder, preventing it from accumulating inside the device, thereby maintaining the cleanliness of the device and the dust removal efficiency.

[0063] In this invention, the gas flow rate is closely related to the powder content in the resin particles. Preferably, when the powder content in the resin particles is less than 10 mg / kg, the gas flow rate is 10-50 m³ / kg. 3 / h, preferably 20-30m 3 / h; when the powder content in the resin particles is 10-50 mg / kg, the gas flow rate is 20-200 m³ / h. 3 / h, preferably 30-100m 3 / h; when the powder content in the resin particles is greater than 50mg / kg, the gas flow rate is 50-300m³ / h. 3 / h, preferably 100-200m 3 / h.

[0064] In this invention, controlling the relationship between the powder content in the resin particles and the gas flow rate within the above-mentioned range is beneficial to improving the powder removal efficiency in EVOH resin particles. Furthermore, the gas flow rate within the above-mentioned range forms a stable airflow during the downward movement of the resin particles, enhancing the separation effect between the powder and the resin particles, and also helps to remove the separated powder, preventing it from re-adhering within the device.

[0065] In this invention, the type of gas is not particularly limited, and various gases conventionally used in the art for de-powdering resin particles can be used in this invention. Preferably, the gas is selected from at least one of air, nitrogen, argon, and helium. In this invention, the air is preferably dehumidified air to prevent moisture in the air from affecting the resin particles.

[0066] In this invention, the flow rate of resin particles added to the resin particle desiccant body is not particularly limited, and those skilled in the art can choose according to actual conditions. Preferably, the flow rate of added resin particles is 100-2000 kg / h.

[0067] In this invention, to prevent the dust-containing gas mixture obtained after dust removal from polluting the air, preferably, the method further includes separating the dust-containing gas mixture to obtain powder and dust removal gas.

[0068] The following combination Figure 1 The method and system of the present invention will be described below, including preferred embodiments:

[0069] Resin particles obtained from the upstream drying section enter the resin de-dust collector body 1 through the feed pipeline 101 for de-dust removal. The resin particles pass through the filter plate 2 layer by layer, and the de-dust resin particle product is discharged into the product hopper through the discharge pipeline 102 at the bottom of the resin de-dust collector body 1. The angle between the filter plate 2 and the horizontal direction is 1.1-2 times the angle of repose of the resin particles, and the pore size of the filter plate 2 is 0.2-0.8 times the average particle size of the resin particles. At the same time as adding resin particles to the resin de-dust collector body 1, gas is introduced into the resin de-dust collector body 1 through the air inlet unit 3 from the air inlet pipeline 103. The gas passes through the filter plate layer by layer, carrying the powder in the resin particles into the air. The resulting powder-containing gas mixture enters the air outlet unit 4 through the air outlet pipeline 104, and then enters the filter unit 5 for separation. The de-dust gas obtained by separation is discharged through the de-dust gas pipeline 105, and the separated powder is discharged through the powder outlet pipeline 106 for collection. By observing the pressure difference, when the filter pressure difference exceeds 10 kPa, the filter is switched to use.

[0070] The present invention will be described in detail below through embodiments.

[0071] In the following examples and comparative examples, the testing methods for the angle of repose of the resin particles, the powder content in the resin particles, and the powder content in the obtained powder-removed resin particle products are the same as those described in the specific embodiments, and will not be repeated here.

[0072] EVOH resin granule raw material 1: The powder content of EVOH resin granules is 40mg / kg, the average particle size of the powder is 80μm, the angle of repose of EVOH resin granules is 25°, and the average particle size of EVOH resin granules is 2500μm.

[0073] EVOH resin granule raw material 2: The powder content of EVOH resin granules is 5mg / kg, the average particle size of the powder is 90μm, the angle of repose of EVOH resin granules is 25°, and the average particle size of EVOH resin granules is 2500μm.

[0074] EVOH resin granule raw material 3: The powder content of the EVOH resin granules is 60mg / kg, the average particle size of the powder is 90μm, the angle of repose of the EVOH resin granules is 25°, and the average particle size of the EVOH resin granules is 2500μm.

[0075] Example 1

[0076] EVOH resin granules 1 are fed into the resin dust removal device from the top at a flow rate of 500 kg / h. Four layers of filter plates (1000 μm pore size, with a total pore area of ​​220 cm² in each layer) are installed inside the device. 2 Each filter plate has an area of ​​350 cm². 2 The filter plate is set at a 35° angle to the horizontal, which is 1.4 times the angle of repose of raw material 1. The pore size of the filter plate is 0.4 times the average particle size of raw material 1. EVOH resin particles pass through the filter plate layer by layer. The resulting powder-free resin particles enter the product hopper from the bottom of the resin powder removal device. The powder content in the powder-free EVOH resin particles is tested to be 1 mg / kg. Simultaneously with the addition of EVOH resin particles to the resin powder removal device, air is introduced into the device from the bottom via a blower, and the airflow is adjusted to 100 m³ / kg by the blower. 3 / h, air passes through 4 layers of filter plates one by one, carrying the powder in the resin particles into the gas. The resulting powder-containing gas mixture enters the filter through the induced draft fan, where the powder and de-powdered gas are separated. The filter uses a 200-mesh filter bag. By observing the pressure difference, when the filter pressure difference exceeds 10kPa, the filter is switched to use.

[0077] Example 2

[0078] EVOH resin granules 2 are fed into the resin dust removal device from the top at a flow rate of 500 kg / h. Three layers of filter plates (pore size 1200 μm, total pore area of ​​150 cm² in each layer) are installed inside the device. 2 Each filter plate has an area of ​​220 cm². 2 The filter plate is set at a 40° angle to the horizontal, which is 1.6 times the angle of repose of raw material 1. The pore size of the filter plate is 0.48 times the average particle size of raw material 3. EVOH resin particles pass through the filter plate layer by layer. The de-dusted EVOH resin particles enter the product hopper from the bottom of the resin de-dusting device. The powder content in the de-dusted EVOH resin particles is tested to be 0.5 mg / kg. Simultaneously with the addition of EVOH resin particles to the resin de-dusting device, air is introduced into the device from the bottom via a blower, with the airflow adjusted to 30 m³ / kg by the blower. 3 / h, air passes through 3 layers of filter plates one by one, carrying the powder in the resin particles into the gas. The resulting powder-containing gas mixture enters the filter through the induced draft fan, where the powder and de-powdered gas are separated. The filter uses a 200-mesh filter bag. By observing the pressure difference, when the filter pressure difference exceeds 10kPa, the filter is switched to use.

[0079] Example 3

[0080] EVOH resin granules 3 are fed into the resin dust removal device from the top at a flow rate of 500 kg / h. Five layers of filter plates (1200 μm pore size, total pore area of ​​380 cm² in each layer) are installed inside the device. 2 Each filter plate has an area of ​​500 cm². 2 The filter plate is set at a 30° angle to the horizontal, which is 1.2 times the angle of repose of raw material 1. The pore size of the filter plate is 0.48 times the average particle size of raw material 3. EVOH resin particles pass through the filter plate layer by layer. The resulting powder-free EVOH resin particles enter the product hopper from the bottom of the resin powder removal device. The powder content in the powder-free EVOH resin particles is tested to be 2 mg / kg. Simultaneously with the addition of EVOH resin particles to the resin powder removal device, air is introduced into the device from the bottom via a blower, with the airflow adjusted to 180 m³ / kg. 3 / h, air passes through 5 layers of filter plates one by one, carrying the powder in the resin particles into the gas. The resulting powder-containing gas mixture enters the filter through the induced draft fan, where the powder and de-powdered gas are separated. The filter uses a 200-mesh filter bag. By observing the pressure difference, when the filter pressure difference exceeds 10kPa, the filter is switched to use.

[0081] Example 4

[0082] The method of Example 1 is followed, except that the angle between the filter plate and the horizontal direction is set to 28°, wherein the angle between the filter plate and the horizontal direction is 1.1 times the angle of repose of raw material 1; the powder content in the EVOH resin granule product obtained by testing is 1.5 mg / kg, the material flow slows down, and it gradually accumulates in the filtration equipment.

[0083] Example 5

[0084] The method is the same as in Example 1, except that the angle between the filter plate and the horizontal direction is set at 50°, which is twice the angle of repose of raw material 1; the powder content in the EVOH resin granule product obtained by testing is 3 mg / kg.

[0085] Example 6

[0086] The method of Example 1 is followed, except that the pore size of the filter plate is set to 600 μm, the pore size of the filter plate is 0.24 times the average particle size of raw material 1, and the total area of ​​the pores in each layer of filter plate remains unchanged; the powder content in the powder-removed resin particle product obtained by testing is 3.5 mg / kg.

[0087] Example 7

[0088] The method of Example 1 is followed, except that the pore size of the filter plate is set to 1600 μm, the pore size of the filter plate is 0.64 times the average particle size of raw material 1, and the total area of ​​the pores in each layer of filter plate remains unchanged; the powder content in the de-powdered resin particle product obtained by testing is 4.5 mg / kg, and some small particles fall directly from the pores of the filter plate.

[0089] Example 8

[0090] The method of Example 1 is followed, except that the angle between the filter plate and the horizontal direction is set to 28°, wherein the angle between the filter plate and the horizontal direction is 1.1 times the angle of repose of raw material 1; the pore size of the filter plate is set to 1500μm, which is 0.6 times the average particle size of raw material 1, and the total area of ​​the pores in each layer of filter plate remains unchanged; the powder content in the de-powdered resin particle product obtained by testing is 5.2mg / kg.

[0091] Example 9

[0092] The method is the same as in Example 1, except that the airflow is adjusted to 300 m³ / h by the fan. 3 / h; The tested resin granule product for powder removal contained 2mg / kg of powder. The airflow was too high, and some particles were blown into the filter bag.

[0093] Comparative Example 1

[0094] The method of Example 1 is followed, except that the angle between the filter plate and the horizontal direction is set at 25°, wherein the angle between the filter plate and the horizontal direction is 1 times the angle of repose of the raw material 1; during the powder removal process, it was found that the resin particles gradually accumulated on the filter plate, and the blower outlet pressure increased until it exceeded the pressure and tripped. The powder content in the powder-removed resin particle product obtained by testing was 30mg / kg.

[0095] Comparative Example 2

[0096] The method of Example 1 is followed, except that the angle between the filter plate and the horizontal direction is set to 60°, wherein the angle between the filter plate and the horizontal direction is 2.4 times the angle of repose of raw material 1; during the powder removal process, it was found that the resin particles moved down too fast, and the powder content in the powder-removed resin particle product was 25mg / kg after testing.

[0097] Comparative Example 3

[0098] The method of Example 1 is followed, except that the pore size of the filter plate is set to 3000 μm, the pore size of the filter plate is 1.2 times the average particle size of raw material 1, and the total area of ​​the pores in each layer of filter plate remains unchanged; the powder content in the powder-removed resin particle product obtained by testing is 20 mg / kg.

[0099] The results of the embodiments show that, compared with the existing technology for removing powder from resin, the resin particle de-powdering device provided by the present invention effectively removes fine powder from EVOH resin particles, reduces powder residue, significantly reduces the powder content in the de-powdered resin particle product, and the whole process is simple, convenient, and has high de-powdering efficiency.

[0100] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A resin particle dust removal device, comprising a resin particle dust removal device body, characterized in that, The resin particle dust removal device has a filter plate inside its main body. The angle between the filter plate and the horizontal direction is 1.1-2 times the angle of repose of the resin particles. The pore size of the filter plate is 0.2-0.8 times the average particle size of the resin particles.

2. The resin particle powder removal device according to claim 1, wherein, The angle between the filter plate and the horizontal direction is 1.2-1.6 times the angle of repose of the resin particles; Preferably, the pore size of the filter plate is 0.3-0.6 times the average particle size of the resin particles.

3. The resin particle dust removal device according to claim 1 or 2, wherein, When the powder content in the resin particles is less than 10 mg / kg, the filter plate has 1-4 layers, preferably 2-3 layers; when the powder content in the resin particles is 10-50 mg / kg, the filter plate has 2-6 layers, preferably 3-5 layers; when the powder content in the resin particles is greater than 50 mg / kg, the filter plate has 2-8 layers, preferably 3-6 layers. Preferably, the included angle between two adjacent filter plates is 10-50°, and more preferably 20-40°; Preferably, when the powder content in the resin particles is less than 10 mg / kg, the area of ​​the filter plate is 100-300 cm². 2 The preferred height is 120-250cm. 2 When the powder content in the resin particles is 10-50 mg / kg, the area of ​​the filter plate is 200-500 cm². 2 The preferred size is 300-400cm. 2 When the powder content in the resin particles is greater than 50 mg / kg, the area of ​​the filter plate is 300-600 cm². 2 The preferred size is 400-500cm. 2 ; Preferably, the area of ​​the filter plate is 150-600 cm² relative to the resin particles at a flow rate of 500 kg / h. 2 Preferably 200-500cm 2 .

4. The resin particle dust removal device according to claim 1 or 2, wherein, The top of the resin particle removal device is provided with a feed inlet, which is connected to the feed pipeline (101); Preferably, the bottom of the resin particle de-powdering device is provided with a discharge port, which is connected to the discharge pipeline (102); Preferably, an air inlet is provided at the bottom of the resin particle dust removal device body near the discharge port area, for sending the gas introduced at the bottom of the resin particle dust removal device body into the interior of the resin particle dust removal device body. Preferably, an air outlet is provided at the top of the resin particle dust removal device body near the feed inlet area to discharge the gas introduced from the bottom of the resin particle dust removal device body.

5. The resin particle dust removal device according to claim 1 or 2, wherein, The filter plate is equipped with a sealing device at the tail end to prevent lower layer gas from entering the upper layer directly without passing through the filter plate.

6. A resin particle dust removal system, characterized in that, The system includes: a resin particle dust removal device according to any one of claims 1-5, an air supply unit, and an exhaust unit; the air supply unit is connected to the air inlet of the resin particle dust removal device via an air inlet pipeline (103), and the exhaust unit is connected to the air outlet of the resin particle dust removal device via an air outlet pipeline (104).

7. The resin particle dust removal system according to claim 6, wherein, The system also includes a filtration unit connected to the exhaust unit; Preferably, the filter bag of the filtration unit has a pore size of 20-200 mesh; Preferably, the air outlet at the top of the filter unit is connected to the de-powdering gas pipeline (105); the powder outlet at the bottom of the filter unit is connected to the powder outlet pipeline (106).

8. A method for removing powder from resin particles, characterized in that, The method is carried out in the resin particle de-dusting system according to any one of claims 6 or 7, and the method includes: Resin particles are added to a resin particle dust removal device for dust removal, resulting in a mixture of dust-removed resin particles and dust-containing gas.

9. The method according to claim 8, wherein, The method further includes: introducing gas from the bottom of the resin particle dust removal device while adding the resin particles; Preferably, when the powder content in the resin particles is less than 10 mg / kg, the gas flow rate is 10-50 m³ / kg. 3 / h, preferably 20-30m 3 / h; when the powder content in the resin particles is 10-50 mg / kg, the gas flow rate is 20-200 m³ / h. 3 / h, preferably 30-100m 3 / h; when the powder content in the resin particles is greater than 50mg / kg, the gas flow rate is 50-300m³ / h. 3 / h, preferably 100-200m 3 / h; Preferably, the gas is selected from at least one of air, nitrogen, argon and helium; Preferably, the flow rate of the added resin particles is 100-2000 kg / h.

10. The method according to claim 8 or 9, wherein, The method further includes separating the powder-containing gas mixture to obtain powder and de-powdered gas.

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