A small-scale bulk polypropylene powder purification skid-mounted device

Abstract

This invention relates to the field of polypropylene powder production technology and equipment technology, and in particular to a small-scale bulk polypropylene powder purification skid-mounted device, comprising a feeder, a purification processor, a drying processor, and a material conveying unit. The end of the feeder is connected to the inlet of the purification processor. Several steam inlet pipes and nitrogen inlet pipes are respectively connected to both sides of the feeder. The purification processor is connected to the drying processor through the material conveying unit, and the end of the drying processor is connected to a discharge receiving system. When processing polypropylene powder, this device utilizes the full contact between steam and nitrogen and the bulk powder to achieve sufficient hydrolysis, absorption, and transfer of volatile substances in the powder to the outside of the purification processor, thereby effectively reducing odorous substances in the powder and ultimately achieving the goal of reducing powder odor.

Description

Technical Field

[0001] This invention relates to the field of polypropylene powder production technology and equipment technology, and particularly to a purification skid structure for use and operation in the production of low-odor polypropylene powder, especially a small bulk polypropylene powder purification skid device. Background Technology

[0002] Polypropylene (PP) is a versatile, low-cost raw material and one of the most widely consumed polymers in the world. It is a high-performance thermoplastic synthetic resin with advantages such as low specific gravity, non-toxicity, easy processing, good flexural strength, and good electrical insulation. Among general-purpose plastics, its production volume ranks second only to polyethylene and polyvinyl chloride (PVC), and its domestic consumption ranks second only to polyethylene. PP has wide applications in the automotive industry, home appliances, electronics, packaging, building materials, and furniture. With increasing environmental protection and quality requirements, the demand for specialty PP materials with low odor and low TVOC content is growing.

[0003] Currently, there are many methods for processing polypropylene materials in the existing technology. For example, the patent document with patent application number CN201210568645.6 provides a low-odor, low-emission modified polypropylene material and its preparation method. The specific steps are as follows: (1) Weigh the raw materials according to the above weight ratio; (2) Mix the raw materials in a high-speed mixer for 3 to 5 minutes; (3) Place the mixed raw materials in a twin-screw extruder, melt extrude, and granulate. The process is as follows: Zone 1 190 to 200°C, Zone 2 200 to 210°C, Zone 3 210 to 220°C, Zone 4 205 to 215°C; The residence time of the entire extrusion process is 1 to 2 minutes, and the pressure is 12 to 18 MPa.

[0004] Based on the full text of the literature, it can be seen that the aforementioned literature uses a specific composition and ratio, employing polypropylene, low-odor, low-emission absorbents, inorganic fillers, toughening agents, and antioxidants to prepare modified polypropylene materials. It utilizes the high specific surface area and high adsorption capacity for emissions from porous carbon, along with the photocatalytic decomposition ability of nano-zinc oxide for organic matter emissions, to achieve in-situ decomposition of organic pollutants, thus achieving a long-lasting low-emission purification effect.

[0005] It absorbs residual monomers, decomposition products, and organic acids in the polypropylene substrate, achieving a significant deodorization effect.

[0006] This is a material produced using a compounding method. It does not fundamentally remove volatile substances from polypropylene powder; it only achieves the apparent phenomenon by reducing volatility and adding some adsorbents through certain means.

[0007] For example, patent document CN202110140675 also discloses a low-odor polypropylene and its preparation method, which is also a material produced by compounding, and similarly does not fundamentally remove volatile substances from polypropylene powder.

[0008] Secondly, patent document CN201921133328.5 also discloses a polypropylene powder purification device for a loop-type polypropylene process. This device is used to improve the drying temperature and impurity removal effect of polypropylene powder. Its main structure includes a polypropylene powder purifier, which has a low-pressure nitrogen inlet, a powder inlet, and a circulating gas outlet at its top, and a gas inlet and a powder outlet at its bottom. It also includes a low-pressure steam pipeline and a nitrogen recovery pipeline. The inlet end of the nitrogen recovery pipeline is connected to the circulating gas outlet; the outlet ends of the low-pressure steam pipeline and the nitrogen recovery pipeline are mixed and then connected to the gas inlet. The polypropylene powder purifier has a perforated distribution plate inside. The perforated distribution plate at the bottom of the polypropylene powder purifier ensures uniform distribution of low-pressure steam and low-pressure nitrogen. The low-pressure steam can further decompose and carry away catalysts, electron donors, and other decomposition products.

[0009] Furthermore, a method for manufacturing a polypropylene odor removal device is disclosed in patent document CN202120309353.5. This device is suitable for removing the odor from polypropylene powder and obtains information on the composition of substances that cause the odor of polypropylene powder by analyzing the components of the coolant.

[0010] This is an experimental unit for laboratory applications. The purpose of this invention is to provide a polypropylene odor removal device that can reduce the odor of polypropylene powder products, and to obtain the composition of odor-producing substances in polypropylene through component analysis of the collected coolant. This is an analytical device for laboratory use.

[0011] Furthermore, patent application CN202120811716.5 discloses a polypropylene powder steam drying device. Its main structure includes a negative pressure steam stripping unit, a vacuum system, a gas-liquid cooling and separation unit, and a drying unit. The gas phase outlet of the negative pressure steam stripping unit is sequentially connected to the vacuum system and the gas-liquid cooling and separation unit, while the powder outlet of the negative pressure steam stripping unit is connected to the drying unit. Using a negative pressure steam stripping unit reduces the boiling point of volatiles to a certain extent, reduces the amount of stripping steam required, and saves steam and cooling energy consumption, correspondingly reducing nitrogen consumption for drying. It is primarily a polypropylene powder steam drying device operating under negative pressure.

[0012] Although the aforementioned patents have improved the methods and equipment for producing polypropylene powder from various perspectives, none of them have fundamentally solved the odor problem in polypropylene powder. Therefore, the current polypropylene powder production technology still has certain shortcomings.

[0013] Therefore, the present invention provides a skid-mounted equipment for the purification and treatment of polypropylene powder using a small bulk method. This equipment is a dedicated device for producing low-odor polypropylene powder and can reduce the TVOC content of polypropylene powder, thereby better solving the problems existing in the prior art. Summary of the Invention

[0014] To solve one of the aforementioned technical problems, this invention uses small-volume polypropylene powder as raw material and processes it to obtain a refined polypropylene powder product with low odor and low TVOC, thus addressing the odor problem in polypropylene powder at its source. The technical solution adopted is: a skid-mounted purification device for small-volume polypropylene powder, including a feeder, a purification processor, a drying processor, and a material conveying unit; the end of the feeder is connected to the inlet of the purification processor; several steam inlet pipes and nitrogen inlet pipes are respectively connected to both sides of the feeder; the purification processor is connected to the drying processor through the material conveying unit; and the end of the drying processor is connected to a discharge receiving system.

[0015] The feeding control of the feeder and material conveying unit is adjusted manually or electrically according to the production situation. The discharge of the purification processor and drying processor adopts the override control method to ensure the processing time and processing effect of the materials.

[0016] The purification processor and the drying processor are arranged in a staggered manner. The material in the purification processor is conveyed outward by the material conveying unit and enters the drying processor in a controlled manner to facilitate powder control.

[0017] The purification processor is equipped with a steam inlet pipe, a nitrogen inlet pipe, and a stirrer, which provide conditions for sufficient contact between the purification medium and the powder. It controls the polypropylene powder to pass through in a dispersed flow, so as to achieve the purpose of sufficient contact between the powder and the medium and improve the purification effect.

[0018] In any of the above embodiments, it is preferred that the feeder includes a main feed pipe, the end of which is connected to the feed inlet of the purification processor, and a range extender feed pump is connected to an inclined branch pipe on one side of the main feed pipe. The range extender feed pump is used to increase the flow rate of the powder entering the purification processor.

[0019] In any of the above embodiments, preferably, the purification processor includes a purification housing, within which several powder discharge pipes are arranged at uniform intervals along the axial direction of the purification housing. The top of each powder discharge pipe is connected to an external feed main pipe via a multi-port connecting pipe. Each powder discharge pipe is equipped with an electric on / off valve, and the end of each powder discharge pipe is provided with a curved section that bends the pipe so that its spray outlet is angled upwards. A horizontal agitator is installed in the lower part of the inner cavity of the purification housing. The agitator's agitator shaft extends movably and sealed to the outside of the purification housing and is connected to a fixed agitator motor. The lower part of the purification housing is an inverted conical discharge section. The lower end of the inverted conical discharge section is connected to the feed end of the material conveying unit, and the end of the material conveying unit is connected to the feed end of the drying processor.

[0020] In any of the above embodiments, it is preferred that the distance between the blades of the horizontal agitator and the inner wall of the purification shell is less than or equal to 20 mm.

[0021] In any of the above schemes, it is preferred that, in order to ensure the smooth and orderly flow of materials, the operating pressure inside the purification shell of the purification processor is controlled at 0 to 10 kPa, and the operating pressure of the drying processor is controlled at 0 to 20 kPa.

[0022] In any of the above solutions, it is preferred that, in order to ensure the material processing effect, the operating temperature inside the purification shell of the purification processor is controlled at 100-130℃, and the operating temperature of the drying processor is controlled at 80-110℃.

[0023] In any of the above embodiments, it is preferred that the purification housing of the purification processor is equipped with a low-speed horizontal agitator to ensure full contact between the powder and steam, while also assisting in controlling the discharge of polypropylene powder through the inverted cone-shaped discharge section to the material conveying unit.

[0024] In any of the above embodiments, it is preferred that a rubber elastic material dispersing membrane is provided above the injection outlet of each of the powder discharge pipes, the rubber elastic material dispersing membrane is fixedly adhered to the inner cavity sidewall of the purification shell on all four sides, and the bottom of the middle section of the rubber elastic material dispersing membrane is convex downward.

[0025] In any of the above embodiments, it is preferred that a plurality of vertically oriented pressure-resetting thin springs are evenly spaced along the circumference above the rubber elastic bulk material membrane, the top of the vertically oriented pressure-resetting thin springs is fixed to the top of the purification housing, and the bottom of the vertically oriented pressure-resetting thin springs is freely disposed and abuts against the bottom of the rubber elastic bulk material membrane.

[0026] In any of the above embodiments, it is preferred to spray an anti-stick coating onto the surface of the rubber elastic bulk film.

[0027] In any of the above embodiments, it is preferred that the inner ends of each of the steam inlet pipes and nitrogen inlet pipes installed on the purification housing extend movably into the inner cavity of the purification housing, and a mist spray head is installed at the inner end of each of the steam inlet pipes and nitrogen inlet pipes. The mist spray head is used to spray high-temperature, high-flow-rate steam or nitrogen outward, and the high-temperature, high-flow-rate steam or nitrogen serves as the purification medium in contact with the powder. A safety pressure relief valve and a gas phase outlet are installed on the purification housing.

[0028] In any of the above embodiments, it is preferred that steam is introduced into the purification housing through a steam distributor on the lower outer side of the purification processor; the outside of the purification housing is also provided with a low-pressure steam heating jacket and a thick insulation blanket to reduce water vapor condensation on the inner wall.

[0029] In any of the above embodiments, it is preferred that the material conveying unit includes an inclined screw conveyor, with the feed end of the screw conveyor inclined downward and the discharge end inclined upward. The feed end of the screw conveyor is connected to the lower end of the inverted conical discharge section of the purification processor, and the discharge end of the screw conveyor is connected to the feed end of the drying processor.

[0030] In any of the above embodiments, preferably, the drying processor includes a gas-solid cyclone separator. The powder inlet of the gas-solid cyclone separator is connected to the outlet of the screw conveyor via a pump-connected pipeline. The gas-solid cyclone separator has a gas separation port at the top and a solid powder separation port at the bottom. A high-temperature nitrogen jet pipe is also installed at the center of the bottom of the gas-solid cyclone separator. The high-temperature nitrogen jet pipe is used to inject high-temperature drying nitrogen into the gas-solid cyclone separator to contact the powder to be dried inside. The high-temperature drying nitrogen is used to dry the powder inside without affecting the normal operation of the gas-solid cyclone separator. The high-temperature nitrogen jet pipe is connected to an external nitrogen heater, and a flow rate booster pump is installed on the high-temperature nitrogen jet pipe.

[0031] In any of the above schemes, it is preferred that the outlet pipe of the gas-solid cyclone separator of the drying processor has a double-layer structure and is inclined downward at 45°, the middle screen is a Johnson tube, and the discharge port is set at the low point of the outlet pipe.

[0032] In any of the above embodiments, it is preferred that a low-temperature nitrogen jet pipe is provided on one side of the solid powder separation port at the lower end of the gas-solid cyclone separator. The inlet end of the low-temperature nitrogen jet pipe is connected to an external low-temperature nitrogen source, and the outlet end of the low-temperature nitrogen jet pipe is used to spray out a reverse nitrogen gas flow that is inclined opposite to the powder and to cool the powder.

[0033] The purpose of the gas-solid cyclone separator in the dryer is to remove residual moisture from the polypropylene powder. Hot nitrogen is circulated as the drying medium to remove the moisture from the polypropylene powder. The gas-solid cyclone separator allows the polypropylene powder to settle by gravity in the airflow, preventing it from being carried out of the dryer by the circulating airflow.

[0034] Depending on the processing capacity and actual production needs, the small bulk polypropylene powder purification skid-mounted device can be an intermittent industrial device or a continuous industrial process device.

[0035] This intermittently operating industrial unit integrates the purification and drying processes into a single device. External pipelines are switched via control valves to achieve the alternation and cyclical operation of purification and drying. Specifically, the purification-drying unit continuously cycles through purification and drying processes, with intermittent feeding and discharging, and a processing capacity of 600 kg / h.

[0036] The industrial process equipment for continuous production has a continuous feeding and discharging capacity of 2000 kg / h.

[0037] The air purifier is equipped with a heating unit, which can be either a steam heating coil or an electric heater.

[0038] The circulating nitrogen in the drying processor is heated by steam or an electric heater.

[0039] The circulating nitrogen discharged from the drying processor is dehydrated again by using a separator and low-temperature water spray to reduce the water content and temperature of the circulating nitrogen. The circulating nitrogen is then dehydrated again by a refrigerated dryer, thus achieving the purpose of recycling.

[0040] Both the purification processor and the drying processor are equipped with a gas phase outlet; a corresponding cyclone separator is installed at the gas phase outlet of both the purification processor and the drying processor to remove and recover fine powder in the gas phase.

[0041] The drying processor is equipped with an external circulating nitrogen unit, and a pulse filter is installed after the cyclone separator to further remove powder from the gas phase.

[0042] The circulating nitrogen used for drying has a continuous replacement and replenishment system.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1. When processing polypropylene powder, this device can fully hydrolyze and absorb the volatile substances in the powder by utilizing the full contact between steam and nitrogen and the bulk powder, and transfer them to the outside of the purification processor, thereby effectively reducing the odor-containing substances in the powder and ultimately achieving the purpose of reducing the odor of the powder.

[0045] 2. The purified powder can be dried and separated for use as raw material in subsequent production, ultimately yielding low-odor polypropylene products, which effectively improves the quality of polypropylene products.

[0046] 3. During the operation of this device, the odor of the product is reduced and the content of volatile matter is effectively removed. After replacing and stripping low-boiling-point substances from the polypropylene powder with steam, the material is dried by removing moisture with nitrogen, thereby effectively obtaining a purified and refined product.

[0047] 4. When the purification processor of this device purifies the powder, it uses steam and nitrogen as purification media. At the same time, it utilizes the high-speed impact of the powder on the rubber elastic material dispersing membrane and relies on the rebound of the rubber elastic material dispersing membrane to fully rebound and disperse the powder, thereby ensuring that the powder fully disperses and falls to fully contact the purification media to achieve purification and ultimately ensure the purification effect. Attached Figure Description

[0048] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn to scale.

[0049] Figure 1 This is a schematic diagram of the connection structure of the present invention.

[0050] Figure 2 This is a schematic diagram of the structure of the present invention.

[0051] Figure 3 This is a schematic diagram of the internal structure of the purification processor of the present invention.

[0052] In the diagram, 1. Feeder; 101. Main feed pipe; 102. Extender feed pump; 2. Purification processor; 201. Purification housing; 202. Powder discharge pipe; 203. Multi-port feed pipe; 204. Arc-shaped curved section; 205. Injection outlet; 206. Agitator motor; 207. Inverted cone discharge section; 208. Rubber elastic material dispersing membrane; 209. Vertical pressure-reset thin spring; 210. Mist spray head; 3. Drying processor 301. Gas-solid cyclone separator; 302. Powder inlet; 303. Pipeline with pump; 304. Gas separation port; 305. Solid powder separation port; 306. High-temperature nitrogen jet pipe; 307. Flow rate booster pump; 308. Low-temperature nitrogen jet pipe; 4. Material conveying unit; 5. Steam inlet pipe; 6. Nitrogen inlet pipe; 7. Wire mesh distributor; 8. Horizontal agitator; 9. Screw conveyor; 10. Intermediate mesh cylinder. Detailed Implementation

[0053] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. The specific structure of the present invention is as follows: Figure 1-3 As shown in the image.

[0054] The volatile matter and odor of polypropylene powder products mainly come from the volatile substances contained in the powder and the residues of various additives used in the production process, such as hydrocarbons (mainly propane and propylene), catalysts, activators, electron donors, etc., with hydrocarbons being the main component.

[0055] Example 1: Intermittent operation of a polypropylene powder purification skid-mounted equipment:

[0056] A small bulk polypropylene powder purification skid-mounted device includes a feeder 1, a purification processor 2, a drying processor 3, and a material conveying unit 4; the end of the feeder 1 is connected to the inlet end of the purification processor 2; several steam inlet pipes 5 and nitrogen inlet pipes 6 are respectively connected to both sides of the feeder 1; the purification processor 2 is connected to the drying processor 3 through the material conveying unit 4; and the end of the drying processor 3 is connected to a discharge receiving system.

[0057] A small-scale polypropylene powder purification skid-mounted device is used to complete the purification and drying operations. It plays different roles in different processing stages: After the feeder 1 feeds the material into the purification processor 2 to a certain level, steam is introduced into the distributor on the bottom outside of the purification processor 2 and enters the purification processor 2 through the steam inlet pipe 5. At the same time, nitrogen is introduced to start the purification process. This device is equivalent to the purification processor 2 in this case.

[0058] After purification, the material enters the drying processor 3, and then hot nitrogen is introduced into it to enter the drying process. At this time, the equipment is equivalent to the drying processor 3.

[0059] The material is fed from the feeder 1 to the upper part of the purification processor 2 and enters the purification processor 2. After reaching the set material level, the feeding stops and the steam valve of the steam inlet pipe 5 is opened for purification treatment.

[0060] After the set time is reached, the powder is discharged from the material conveying unit 4 to the drying processor 3, while the steam valve is closed and the hot nitrogen valve is opened to perform the drying operation.

[0061] After the set time is reached, the hot nitrogen is switched to cold nitrogen to perform a cooling operation. Once the material reaches a certain temperature, the processing is complete. At this point, the discharge valve opens, and the material is discharged into the discharge receiving system. After unloading is finished, the discharge valve is closed.

[0062] This skid-mounted equipment is automatically controlled by a PLC, a technology already in use. Various parameters in the above-mentioned processing can be set and adjusted on a touchscreen, and the skid-mounted equipment can also be set to perform single-process or continuous processing. In continuous processing mode, the system automatically executes the above operations and repeats the cycle.

[0063] The feeding control of feeder 1 and material conveying unit 4 is adjusted manually or electrically according to the production situation. The discharge of purification processor 2 and drying processor 3 adopts override control to ensure the processing time and effect of materials.

[0064] The purification processor 2 and the drying processor 3 are arranged in a staggered manner. The material of the purification processor 2 is conveyed outward by the material conveying unit 4 and enters the drying processor 3 in a controlled manner to facilitate powder control.

[0065] The steam inlet pipe 5, nitrogen inlet pipe 6, and agitator in the purification processor 2 provide conditions for sufficient contact between the purification medium and the powder, control the polypropylene powder to pass through in a dispersed flow, achieve the purpose of sufficient contact between the powder and the medium, and improve the purification treatment effect.

[0066] In any of the above embodiments, preferably, the purification processor 2 includes a purification housing 201, within which a plurality of powder discharge pipes 202 are arranged at uniform intervals along the axial direction of the purification housing 201. The top of each powder discharge pipe 202 is connected to an external feed main pipe 101 via a multi-port connecting pipe 203. Each powder discharge pipe 202 is equipped with an electric on / off valve, and the end of each powder discharge pipe 202 is provided with a section bent by an arc-shaped bending section 204. The spray outlet 205 is angled upwards; a horizontal agitator 8 is installed in the lower part of the inner cavity of the purification housing 201. The agitator shaft of the horizontal agitator 8 is movable and sealed to the outside of the purification housing 201 and is connected to a fixed agitator motor 206. The lower part of the purification housing 201 is an inverted cone-shaped discharge section 207. The lower end of the inverted cone-shaped discharge section 207 is connected to the feed end of the material conveying unit 4. The end of the material conveying unit 4 is connected to the feed end of the drying processor 3.

[0067] In any of the above embodiments, it is preferred that a rubber elastic material dispersing membrane 208 is provided above the spray outlet 205 of each of the powder discharge pipes 202. The rubber elastic material dispersing membrane 208 is fixedly bonded to the inner cavity side wall of the purification housing 201 on all four sides, and the bottom of the middle section of the rubber elastic material dispersing membrane 208 is convex downward.

[0068] In any of the above embodiments, it is preferred that a plurality of vertical pressure-resetting thin springs 209 are evenly spaced around the periphery of the rubber elastic bulk material membrane 208. The top of the vertical pressure-resetting thin springs 209 is fixed to the top of the purification housing 201, and the bottom of the vertical pressure-resetting thin springs 209 is freely disposed and abuts against the bottom of the rubber elastic bulk material membrane 208.

[0069] After entering the purification housing 201, the powder enters the powder discharge pipes 202 in various open states through the multi-port receiving pipe 203. After passing through the corresponding arc-shaped bending section 204, it is ejected at high speed and obliquely upward from the spray outlet 205. The sprayed powder will impact the bottom of the middle section of the rubber elastic dispersing membrane 208. At this time, the rubber elastic dispersing membrane 208 is deformed by the upward impact force, thereby compressing the vertical pressure-reset thin springs 209. Intermittent feeding and spraying are adopted here. After the spraying is completed, the impacted material will be fully dispersed during the rapid rebound of the rubber elastic dispersing membrane 208, ultimately achieving the purpose of fully dispersing the powder below. The dispersed powder falls downward in a dispersed form, and finally, the internal volatile substances are removed by the purification of the sprayed steam and nitrogen, thereby improving the quality of the powder and reducing its odor.

[0070] In actual operation, by controlling and adjusting the spray frequency to increase, the powder sprayed obliquely upward from the spray outlet 205 can directly collide with the falling powder from the previous spray, thereby better dispersing the currently sprayed powder and ultimately achieving the purpose of effectively dispersing the material.

[0071] In any of the above embodiments, it is preferred to spray an anti-stick coating onto the surface of the rubber elastic bulk film 208.

[0072] It can effectively prevent adhesion.

[0073] In any of the above embodiments, it is preferred that the inner ends of each of the steam inlet pipes 5 and the nitrogen inlet pipes 6 installed on the purification housing 201 extend movably into the inner cavity of the purification housing 201, and a mist spray head 210 is installed at the inner end of each of the steam inlet pipes 5 and the nitrogen inlet pipes 6. The mist spray head 210 is used to spray high-temperature, high-flow-rate steam or nitrogen outward, and the high-temperature, high-flow-rate steam or nitrogen serves as the purification medium in contact with the powder. A safety pressure relief valve and a gas phase outlet are installed on the purification housing 201.

[0074] The spray pattern of the mist nozzle 210 can better ensure that steam, nitrogen and powder are in full contact, thus improving the purification effect.

[0075] The safety relief valve mainly serves to relieve pressure safely. The gas phase outlet end is mainly used to discharge the gas after the purification reaction and allow it to be further processed by external equipment.

[0076] In any of the above embodiments, it is preferred that steam is introduced into the purification housing 201 through a steam distributor on the lower outer side of the purification processor 2; the purification housing 201 is also provided with a low-pressure steam heating jacket and a thick insulation blanket to reduce water vapor condensation on the inner wall.

[0077] In any of the above embodiments, it is preferred that the material conveying unit 4 includes an inclined screw conveyor 9, with the feed end of the screw conveyor 9 inclined downward and the discharge end inclined upward. The feed end of the screw conveyor 9 is connected to the lower end of the inverted conical discharge section 207 of the purification processor 2, and the discharge end of the screw conveyor 9 is connected to the feed end of the drying processor 3.

[0078] Controlling the working state of the screw conveyor 9 can effectively realize the material conveying volume and speed.

[0079] In any of the above embodiments, it is preferred that the drying processor 3 includes a gas-solid cyclone separator 301, the powder inlet 302 of the gas-solid cyclone separator 301 is connected to the discharge end of the screw conveyor 9 through a pump pipeline 303, and the gas-solid cyclone separator 301 is provided with a gas separation port 304 at the top and a solid powder separation port 305 at the bottom.

[0080] In any of the above embodiments, a preferred embodiment is that a high-temperature nitrogen jet pipe 306 is also installed at the center of the bottom of the gas-solid cyclone separator 301. The high-temperature nitrogen jet pipe 306 is used to inject high-temperature drying nitrogen into the gas-solid cyclone separator 301 to contact the powder to be dried inside. The high-temperature drying nitrogen is used to dry the powder inside without affecting the normal operation of the gas-solid cyclone separator 301. The high-temperature nitrogen jet pipe 306 is connected to an external nitrogen heater, and a flow rate booster pump 307 is installed on the high-temperature nitrogen jet pipe 306.

[0081] The high-temperature nitrogen jet pipe 306 can inject high-temperature nitrogen into the interior of the gas-solid cyclone separator 301. After the high-temperature nitrogen comes into contact with the powder inside, it can remove the moisture from the powder. At the same time, the high-temperature nitrogen is continuously supplied by an external gas source.

[0082] In any of the above schemes, it is preferred that the outlet pipe of the gas-solid cyclone separator 301 of the drying processor 3 has a double-layer structure and is inclined downward at 45°, the middle screen is a Johnson tube, and the discharge port is set at the low point of the outlet pipe.

[0083] In any of the above embodiments, it is preferred that a low-temperature nitrogen jet pipe 308 is provided on one side of the solid powder separation port at the lower end of the gas-solid cyclone separator 301. The inlet end of the low-temperature nitrogen jet pipe 308 is connected to an external low-temperature nitrogen source, and the outlet end of the low-temperature nitrogen jet pipe 308 is used to spray out a reverse nitrogen gas flow that is inclined opposite to the powder and to cool the powder.

[0084] The low-temperature nitrogen jet pipe 308 can effectively cool down the powder.

[0085] The purpose of the gas-solid cyclone separator 301 in the dryer 3 is to remove residual moisture from the polypropylene powder. The drying medium uses circulating hot nitrogen gas to remove the moisture from the polypropylene powder. The gas-solid cyclone separator 301 allows the polypropylene powder to settle by gravity in the airflow, preventing the polypropylene powder from being carried out of the dryer 3 by the circulating airflow.

[0086] Hot nitrogen gas enters through a screen in the middle mesh cylinder at the lower outlet end and comes into contact with the polypropylene powder.

[0087] Fresh, low-temperature nitrogen gas is introduced into the feeding section to achieve countercurrent contact with the polypropylene powder at an inclined direction, which enhances the drying effect and also has a cooling effect.

[0088] The purification medium used by the purification processor 2 is steam and nitrogen, with a ratio between 6:1 and 2:1.

[0089] The drying medium used in the drying processor 3 is nitrogen.

[0090] The height-to-diameter ratio of the purification processor 2 and the drying processor 3 is in the range of 1.8:1 to 3.6:1;

[0091] To ensure the processing effect of materials, the volume ratio of powder material to purification medium in the operation of purification processor 2 is 1:60 to 1:150, and the volume ratio of powder material to drying medium in the operation of drying processor 3 is 1:150 to 1:500.

[0092] Depending on the processing capacity and actual production needs, the small bulk polypropylene powder purification skid-mounted device can be an intermittent industrial device or a continuous industrial process device.

[0093] This intermittently operating industrial unit comprises a single device for both purification and drying processes. External pipelines are switched via control valves to achieve the alternation and cycling of purification and drying operations. Specifically, purification and drying processor 3 operates in a continuous cycle of purification and drying processes, with intermittent feeding and discharging, and a processing capacity of 600 kg / h.

[0094] The industrial process equipment for continuous production has a continuous feeding and discharging capacity of 2000 kg / h.

[0095] The purifier 2 is equipped with a heating unit, which can be either a steam heating coil or an electric heater.

[0096] The circulating nitrogen in the drying processor 3 is heated by steam or an electric heater.

[0097] The circulating nitrogen discharged from the dryer 3 is treated by a separator and low-temperature water spray to reduce the water content and temperature of the circulating nitrogen. Then, it is sent to a refrigerated dryer to dehydrate the circulating nitrogen again, thereby achieving the purpose of recycling.

[0098] Both the purification processor 2 and the drying processor 3 are equipped with a gas phase outlet; both the purification processor 2 and the drying processor 3 are equipped with corresponding cyclone separators at the gas phase outlet to remove and recover fine powder in the gas phase.

[0099] The drying processor 3 is equipped with an external circulating nitrogen unit, and a pulse filter is set after the cyclone separator to further remove powder from the gas phase.

[0100] The circulating nitrogen used for drying has a continuous replacement and replenishment system.

[0101] Example 2: Small bulk polypropylene powder purification skid-mounted device as a dual-unit purification skid-mounted equipment for intermittent operation:

[0102] The working principle and control of this embodiment are similar to those of Embodiment 1.

[0103] The difference from Example 1 is as follows:

[0104] Purification processor 2 and drying processor 3 are two independently set processors, and the materials in both processors are intermittently fed in and out.

[0105] The feeding and discharging of materials are controlled by on / off control valves. The discharge pipe of the dryer 3 is inclined downwards and enters the discharge receiving system below the dryer 3 through the control valve.

[0106] The examples are for applications in existing production facilities where polypropylene powder purification is required.

[0107] The drying processor 3 is located on the upper floors of the plant, which facilitates the flow of materials along the direction of gravity, reduces external conveying energy, reduces the occurrence of problems and failure rate, and improves efficiency.

[0108] Example 3: Continuous purification skid-mounted equipment:

[0109] A small bulk polypropylene powder purification skid-mounted device includes a feeder 1, a purification processor 2, a drying processor 3, and a material conveying unit 4; the end of the feeder 1 is connected to the inlet end of the purification processor 2; several steam inlet pipes 5 and nitrogen inlet pipes 6 are respectively connected to both sides of the feeder 1; the purification processor 2 is connected to the drying processor 3 through the material conveying unit 4; and the end of the drying processor 3 is connected to a discharge receiving system.

[0110] The powder is fed into the purification processor 2 through the feeder 1. Steam enters the purification processor 2 through the steam distributor on one side of the lower part of the steam distributor 5. In order to make the steam fully contact the polypropylene powder, the bottom of the purification processor 2 is also equipped with a wire mesh distributor 7.

[0111] The purification processor 2 is equipped with a low-pressure steam heating jacket and a thick insulation blanket on the outside to prevent water vapor from condensing on the inner wall of the purification processor 2, thereby preventing the formation of a corrosive environment of chloride ions.

[0112] The purification processor 2 is a container with a low-speed horizontal agitator 8, which is used to agitate the powder, so that the powder and steam can come into full contact, while preventing powder bridging, and assisting in controlling the polypropylene powder to pass through the entire container in a dispersed flow form, so as to achieve an orderly flow queue of first-in-first-out.

[0113] Under the influence of gravity and a small pressure difference, the polypropylene powder at the bottom of the purification processor 2 enters the screw conveyor 9 through the bottom outlet pipe and rotary valve, and then enters the drying processor 3 for drying.

[0114] The purpose of drying is to remove residual moisture from the polypropylene powder.

[0115] The drying process uses a hot nitrogen circulation system to remove moisture from the polypropylene powder in the dryer 3.

[0116] Hot nitrogen gas enters the drying processor 3 in two streams. The dried polypropylene powder enters the discharge pipe by gravity and is then transported to the granulation unit at the rear by the screw conveyor 9.

[0117] Saturated hot nitrogen gas exits from the top of the dryer 3 and enters the top cyclone separator of the dryer 3 to separate the polypropylene powder entrained in the gas flow. The circulating hot nitrogen gas and cold water come into countercurrent contact in the condenser, the water vapor in the saturated hot nitrogen gas is condensed, and the fine polypropylene particles entrained in the gas flow are washed away.

[0118] Clean nitrogen gas is discharged through the demister at the top of the condenser to the inlet of the circulating nitrogen compressor. After being compressed by the circulating nitrogen compressor, it is heated and then returned to the dryer 3.

[0119] The condenser has an overflow pipe at the bottom to drain condensate, ensuring that the condenser maintains a constant liquid level.

[0120] When the system pressure is insufficient due to nitrogen loss, nitrogen will be automatically replenished through the regulating valve.

[0121] An analyzer is installed at the outlet of the circulating nitrogen compressor in the nitrogen circulation loop to detect the combustible gas content and humidity of the circulating nitrogen, which can determine the drying effect and adjust the drying operation process in a timely manner.

[0122] To prevent air from entering and causing material denaturation, the circulation system is always kept under positive pressure.

[0123] The feeding control of feeder 1 and material conveying unit 4 is adjusted manually or electrically according to the production situation. The discharge of purification processor 2 and drying processor 3 adopts override control to ensure the processing time and effect of materials.

[0124] The purification processor 2 and the drying processor 3 are arranged in a staggered manner. The material of the purification processor 2 is conveyed outward by the material conveying unit 4 and enters the drying processor 3 in a controlled manner to facilitate powder control.

[0125] The steam inlet pipe 5, nitrogen inlet pipe 6, and agitator in the purification processor 2 provide conditions for sufficient contact between the purification medium and the powder, control the polypropylene powder to pass through in a dispersed flow, achieve the purpose of sufficient contact between the powder and the medium, and improve the purification treatment effect.

[0126] In any of the above embodiments, it is preferred that the feeder 1 includes a main feed pipe 101, the end of which is connected to the feed inlet of the purification processor 2, and a range extender feed pump 102 is connected to an inclined branch pipe on one side of the main feed pipe 101. The range extender feed pump 102 is used to increase the flow rate of powder entering the purification processor 2.

[0127] The feed pipe 101 is connected to an external material source and can continuously transport powder from the feed pipe 101 to the purification processor 2 through the conveying action of an external conveying pump; the main purpose of the extended feed pump 102 set here is to increase the flow rate and velocity of the powder entering the purification processor 2.

[0128] In any of the above embodiments, preferably, the purification processor 2 includes a purification housing 201, within which a plurality of powder discharge pipes 202 are arranged at uniform intervals along the axial direction of the purification housing 201. The top of each powder discharge pipe 202 is connected to an external feed main pipe 101 via a multi-port connecting pipe 203. Each powder discharge pipe 202 is equipped with an electric on / off valve, and the end of each powder discharge pipe 202 is provided with a section bent by an arc-shaped bending section 204. The spray outlet 205 is angled upwards; a horizontal agitator 8 is installed in the lower part of the inner cavity of the purification housing 201. The agitator shaft of the horizontal agitator 8 is movable and sealed to the outside of the purification housing 201 and is connected to a fixed agitator motor 206. The lower part of the purification housing 201 is an inverted cone-shaped discharge section 207. The lower end of the inverted cone-shaped discharge section 207 is connected to the feed end of the material conveying unit 4. The end of the material conveying unit 4 is connected to the feed end of the drying processor 3.

[0129] After being thoroughly purified by steam and nitrogen, the powder falling downwards falls directly into the inner cavity at the bottom of the purification shell 201. Under the action of the horizontal agitator 8, the powder is continuously agitated and discharged outwards from the inverted cone-shaped discharge section 207 to the feed end of the material conveying unit 4.

[0130] In any of the above embodiments, it is preferred that the distance between the blades of the horizontal stirrer 8 and the inner wall of the purification housing 201 is less than or equal to 20 mm.

[0131] In any of the above schemes, it is preferred that, in order to ensure the smooth and orderly flow of materials, the operating pressure inside the purification housing 201 of the purification processor 2 is controlled at 0 to 10 kPa, and the operating pressure of the drying processor 3 is controlled at 0 to 20 kPa.

[0132] In any of the above schemes, it is preferred that, in order to ensure the material processing effect, the operating temperature inside the purification housing 201 of the purification processor 2 is controlled at 100-130°C, and the operating temperature of the drying processor 3 is controlled at 80-110°C.

[0133] In any of the above embodiments, it is preferred that the purification housing 201 of the purification processor 2 is equipped with a low-speed horizontal agitator 8, which is used to ensure that the powder and steam are in full contact, and at the same time assists in controlling the polypropylene powder to be discharged to the material conveying unit 4 through the inverted cone discharge section 207.

[0134] In any of the above embodiments, it is preferred that a rubber elastic material dispersing membrane 208 is provided above the spray outlet 205 of each of the powder discharge pipes 202. The rubber elastic material dispersing membrane 208 is fixedly bonded to the inner cavity side wall of the purification housing 201 on all four sides, and the bottom of the middle section of the rubber elastic material dispersing membrane 208 is convex downward.

[0135] In any of the above embodiments, it is preferred that a plurality of vertical pressure-resetting thin springs 209 are evenly spaced around the periphery of the rubber elastic bulk material membrane 208. The top of the vertical pressure-resetting thin springs 209 is fixed to the top of the purification housing 201, and the bottom of the vertical pressure-resetting thin springs 209 is freely disposed and abuts against the bottom of the rubber elastic bulk material membrane 208.

[0136] After entering the purification housing 201, the powder enters the powder discharge pipes 202 in various open states through the multi-port receiving pipe 203. After passing through the corresponding arc-shaped bending section 204, it is ejected at high speed and obliquely upward from the spray outlet 205. The sprayed powder will impact the bottom of the middle section of the rubber elastic dispersing membrane 208. At this time, the rubber elastic dispersing membrane 208 is deformed by the upward impact force, thereby compressing the vertical pressure-reset thin springs 209. Intermittent feeding and spraying are adopted here. After the spraying is completed, the impacted material will be fully dispersed during the rapid rebound of the rubber elastic dispersing membrane 208, ultimately achieving the purpose of fully dispersing the powder below. The dispersed powder falls downward in a dispersed form, and finally, the internal volatile substances are removed by the purification of the sprayed steam and nitrogen, thereby improving the quality of the powder and reducing its odor.

[0137] In actual operation, by controlling and adjusting the spray frequency to increase, the powder sprayed obliquely upward from the spray outlet 205 can directly collide with the falling powder from the previous spray, thereby better dispersing the currently sprayed powder and ultimately achieving the purpose of effectively dispersing the material.

[0138] In any of the above embodiments, it is preferred to spray an anti-stick coating onto the surface of the rubber elastic bulk film 208.

[0139] In any of the above embodiments, it is preferred that the inner ends of each of the steam inlet pipes 5 and the nitrogen inlet pipes 6 installed on the purification housing 201 extend movably into the inner cavity of the purification housing 201, and a mist spray head 210 is installed at the inner end of each of the steam inlet pipes 5 and the nitrogen inlet pipes 6. The mist spray head 210 is used to spray high-temperature, high-flow-rate steam or nitrogen outward, and the high-temperature, high-flow-rate steam or nitrogen serves as the purification medium in contact with the powder. A safety pressure relief valve and a gas phase outlet are installed on the purification housing 201.

[0140] In any of the above embodiments, it is preferred that steam is introduced into the purification housing 201 through a steam distributor on the lower outer side of the purification processor 2; the purification housing 201 is also provided with a low-pressure steam heating jacket and a thick insulation blanket to reduce water vapor condensation on the inner wall.

[0141] In any of the above embodiments, it is preferred that the material conveying unit 4 includes an inclined screw conveyor 9, with the feed end of the screw conveyor 9 inclined downward and the discharge end inclined upward. The feed end of the screw conveyor 9 is connected to the lower end of the inverted conical discharge section 207 of the purification processor 2, and the discharge end of the screw conveyor 9 is connected to the feed end of the drying processor 3.

[0142] In any of the above embodiments, preferably, the drying processor 3 includes a gas-solid cyclone separator 301. The powder inlet 302 of the gas-solid cyclone separator 301 is connected to the outlet end of the screw conveyor 9 through a pump-connected pipeline 303. The gas-solid cyclone separator 301 has a gas separation port 304 at the top and a solid powder separation port 305 at the bottom. A high-temperature nitrogen jet pipe 306 is also installed at the center of the bottom of the gas-solid cyclone separator 301. The high-temperature nitrogen jet pipe 306 is used to inject high-temperature drying nitrogen into the gas-solid cyclone separator 301 to contact the powder to be dried inside. The high-temperature drying nitrogen is used to dry the powder inside and does not affect the normal operation of the gas-solid cyclone separator 301. The high-temperature nitrogen jet pipe 306 is connected to an external nitrogen heater, and a flow rate booster pump 307 is installed on the high-temperature nitrogen jet pipe 306.

[0143] The high-temperature nitrogen jet pipe 306 can inject high-temperature nitrogen into the interior of the gas-solid cyclone separator 301. After the high-temperature nitrogen comes into contact with the powder inside, it can remove the moisture from the powder. At the same time, the high-temperature nitrogen is continuously supplied by an external gas source.

[0144] In any of the above embodiments, it is preferred that the outlet pipe of the gas-solid cyclone separator 301 of the drying processor 3 has a double-layer structure and is inclined downward at 45°. The middle screen cylinder adopts a Johnson tube and is connected to a high-temperature nitrogen jet pipe 306. A powder separation port 305 is set at the low point of the outlet pipe.

[0145] In any of the above embodiments, it is preferred that a low-temperature nitrogen jet pipe 308 is provided on one side of the solid powder separation port at the lower end of the gas-solid cyclone separator 301. The inlet end of the low-temperature nitrogen jet pipe 308 is connected to an external low-temperature nitrogen source, and the outlet end of the low-temperature nitrogen jet pipe 308 is used to spray out a reverse nitrogen gas flow that is inclined opposite to the powder and to cool the powder.

[0146] The purpose of the gas-solid cyclone separator 301 in the dryer 3 is to remove residual moisture from the polypropylene powder. The drying medium uses circulating hot nitrogen gas to remove the moisture from the polypropylene powder. The gas-solid cyclone separator 301 allows the polypropylene powder to settle by gravity in the airflow, preventing the polypropylene powder from being carried out of the dryer 3 by the circulating airflow.

[0147] Hot nitrogen gas enters through a screen cylinder of the intermediate mesh cylinder 10 at the lower outlet end and comes into contact with the polypropylene powder.

[0148] Fresh, low-temperature nitrogen gas is introduced into the feeding section to achieve countercurrent contact with the polypropylene powder at an inclined direction, which enhances the drying effect and also has a cooling effect.

[0149] The purification medium used by the purification processor 2 is steam and nitrogen, with a ratio between 6:1 and 2:1.

[0150] The drying medium used in the drying processor 3 is nitrogen.

[0151] The height-to-diameter ratio of the purification processor 2 and the drying processor 3 is in the range of 1.8:1 to 3.6:1;

[0152] To ensure the processing effect of materials, the volume ratio of powder material to purification medium in the operation of purification processor 2 is 1:60 to 1:150, and the volume ratio of powder material to drying medium in the operation of drying processor 3 is 1:150 to 1:500.

[0153] Depending on the processing capacity and actual production needs, the small bulk polypropylene powder purification skid-mounted device can be an intermittent industrial device or a continuous industrial process device.

[0154] This intermittently operating industrial unit comprises a single device for both purification and drying processes. External pipelines are switched via control valves to achieve the alternation and cycling of purification and drying operations. Specifically, purification and drying processor 3 operates in a continuous cycle of purification and drying processes, with intermittent feeding and discharging, and a processing capacity of 600 kg / h.

[0155] The industrial process equipment for continuous production has a continuous feeding and discharging capacity of 2000 kg / h.

[0156] The purifier 2 is equipped with a heating unit, which can be either a steam heating coil or an electric heater.

[0157] The circulating nitrogen in the drying processor 3 is heated by steam or an electric heater.

[0158] The circulating nitrogen discharged from the dryer 3 is treated by a separator and low-temperature water spray to reduce the water content and temperature of the circulating nitrogen. Then, it is sent to a refrigerated dryer to dehydrate the circulating nitrogen again, thereby achieving the purpose of recycling.

[0159] Both the purification processor 2 and the drying processor 3 are equipped with a gas phase outlet; both the purification processor 2 and the drying processor 3 are equipped with corresponding cyclone separators at the gas phase outlet to remove and recover fine powder in the gas phase.

[0160] The drying processor 3 is equipped with an external circulating nitrogen unit, and a pulse filter is set after the cyclone separator to further remove powder from the gas phase.

[0161] The circulating nitrogen used for drying has a continuous replacement and replenishment system.

[0162] Example 4: Continuous purification skid-mounted equipment

[0163] This embodiment is similar to Example 3, except that the feeding and discharging processes are different.

[0164] The feeding unit consists of a hopper and a rotary valve. The hopper is located above the purification processor 2 and flows into the purification processor 2 by gravity.

[0165] The discharge pipe is inclined downwards, and after the conveying flow is controlled by a rotary valve, it enters the hopper below the drying processor 3.

[0166] This embodiment is used in existing production facilities where polypropylene powder purification is required.

[0167] The drying processor 3 is located on the upper floors of the plant, which facilitates the flow of materials along the direction of gravity, reduces external conveying energy, reduces the occurrence of problems and failure rate, and improves efficiency.

[0168] Odor testing is performed on the polypropylene powder processed by this device. If the odor meets the standard, the above process is completed. Otherwise, the operating conditions in the above process need to be adjusted, such as the temperature, the amount of purification medium and drying medium used, etc.

[0169] A simple on-site method for detecting the odor of polypropylene powder after purification treatment:

[0170] 1. Utensils: 350mL double-walled insulated glass cup, hot water at a temperature not lower than 95℃

[0171] 2. Steps:

[0172] 1) Pour 150mL of hot water into a glass, shake it a few times, pour it out, and repeat once.

[0173] 2) Take 10g of the polypropylene powder to be tested and put it into a glass, pour in 150mL of hot water, shake it up and down three times, and let it stand for 10 seconds.

[0174] 3) Open the glass lid and check the odor.

[0175] 3. Judgment criteria:

[0176] 1) Qualified: No obvious pungent odor, or no odor that makes people feel uncomfortable.

[0177] 2) Unacceptable: It has a pungent odor or an unpleasant odor.

[0178] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. For those skilled in the art, any alternative improvements or modifications made to the embodiments of the present invention fall within the protection scope of the present invention.

[0179] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A small-scale bulk polypropylene powder purification skid-mounted device, characterized in that: It includes a feeder, a purification processor, a drying processor, and a material conveying unit; the end of the feeder is connected to the inlet of the purification processor; several steam inlet pipes and nitrogen inlet pipes are respectively connected to both sides of the feeder; the purification processor is connected to the drying processor through the material conveying unit; and the end of the drying processor is connected to the discharge receiving system. The feeder includes a main feed pipe, the end of which is connected to the feed inlet of the purification processor. An extender feed pump is connected to an inclined branch pipe on one side of the main feed pipe. The extender feed pump is used to increase the flow rate of the powder entering the purification processor. The purification processor includes a purification housing, within which several powder discharge pipes are arranged at uniform intervals along the axial direction of the purification housing. The top of each powder discharge pipe is connected to an external feed main pipe via a multi-port connecting pipe. Each powder discharge pipe is equipped with an electric on / off valve, and the end of each powder discharge pipe is provided with a curved section that bends the pipe so that its spray outlet is angled upwards. A horizontal agitator is installed in the lower part of the inner cavity of the purification housing. The agitator's agitator shaft extends movably and sealed to the outside of the purification housing and is connected to a fixed agitator motor. The lower part of the purification housing is an inverted conical discharge section. The lower end of the inverted conical discharge section is connected to the feed end of the material conveying unit, and the end of the material conveying unit is connected to the feed end of the drying processor. A rubber elastic material dispersing membrane is provided above the injection outlet of each of the powder discharge pipes. The rubber elastic material dispersing membrane is fixedly bonded to the inner cavity side wall of the purification shell on all four sides. The bottom of the middle section of the rubber elastic material dispersing membrane is convex downward. The inner ends of each of the steam inlet pipes and nitrogen inlet pipes installed on the purification housing extend movably into the inner cavity of the purification housing. A mist spray head is installed at the inner end of each of the steam inlet pipes and nitrogen inlet pipes. The mist spray head is used to spray high-temperature, high-flow-rate steam or nitrogen outward. The high-temperature, high-flow-rate steam or nitrogen serves as the purification medium that contacts the powder. A safety pressure relief valve and a gas phase outlet are installed on the purification housing. The drying processor includes a gas-solid cyclone separator. A low-temperature nitrogen jet pipe is provided on one side of the solid powder separation port at the lower end of the gas-solid cyclone separator. The inlet end of the low-temperature nitrogen jet pipe is connected to an external low-temperature nitrogen source. The outlet end of the low-temperature nitrogen jet pipe is used to spray out a reverse nitrogen gas flow that is inclined opposite to the powder and to cool the powder.

2. The small bulk polypropylene powder purification skid-mounted device according to claim 1, characterized in that: Several vertically oriented, pressure-resetting thin springs are evenly spaced around the perimeter of the rubber elastic bulk material membrane. The top of each vertically oriented, pressure-resetting thin spring is fixed to the top of the purification housing, and the bottom of each vertically oriented, pressure-resetting thin spring is freely positioned and abuts against the bottom of the rubber elastic bulk material membrane.

3. The small-scale bulk polypropylene powder purification skid-mounted device according to claim 2, characterized in that: An anti-stick coating is sprayed onto the surface of the rubber elastic bulk film.

4. The small bulk polypropylene powder purification skid-mounted device according to claim 3, characterized in that: The material conveying unit includes an inclined screw conveyor with its feed end inclined downward and its discharge end inclined upward. The feed end of the screw conveyor is connected to the lower end of the inverted cone discharge section of the purification processor, and the discharge end of the screw conveyor is connected to the feed end of the drying processor.

5. A small bulk polypropylene powder purification skid-mounted device according to claim 4, characterized in that: The powder inlet of the gas-solid cyclone separator is connected to the outlet of the screw conveyor via a pump-connected pipeline. The gas-solid cyclone separator has a gas separation port at the top and a solid powder separation port at the bottom. A high-temperature nitrogen jet pipe is also installed at the center of the bottom of the gas-solid cyclone separator. The high-temperature nitrogen jet pipe is used to inject high-temperature drying nitrogen into the gas-solid cyclone separator to contact the powder to be dried inside. The high-temperature drying nitrogen is used to dry the powder inside without affecting the normal operation of the gas-solid cyclone separator. The high-temperature nitrogen jet pipe is connected to an external nitrogen heater, and a flow rate booster pump is installed on the high-temperature nitrogen jet pipe.

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