CN104139471B - A washing and purification method for recycling and reusing film-type waste plastics - Google Patents

Abstract

The invention discloses a washing and purifying system and a washing and purifying method for recycling and reusing film waste plastics, which are characterized in that a shredder is adopted to shear waste materials mechanically, then heavy impurities are removed by primarily washing sediments, then the materials are washed in a multi-drum washing and separating device through a multi-stage rotary drum, the upward flow velocity of washing water injected into lower water inlets is controlled, light impurities mixed in the materials are effectively removed, or different materials with different specific gravities are separated by washing, then the obtained plastic material pieces are sheared, kneaded and homogenized into small pieces and granular particles by a double-screw impregnator, and the small pieces and the granular particles are dried and stored for later use. The method and the system can realize comprehensive utilization of solid wastes in a paper mill and respective recycling of waste paper fibers and waste plastics, can realize automatic and large-scale industrial production, have the comprehensive utilization rate of over 90 percent, can reduce water consumption by 50-80 percent through recycling of washing water, reduce environmental pollution, ensure the continuity of production, save production space and have remarkable significance.

Description

A washing and purification method for recycling and reusing film-type waste plastics

technical field

The invention relates to a recycling, washing and purifying system and a washing and purifying method for waste plastics, in particular to a washing and purifying system and a washing and purifying method for recycling and reusing thin-film waste plastics.

Background technique

The development of the plastics industry has brought great benefits to mankind, but it has left endless troubles, namely "white pollution". Since there are plastic products, old plastics are inevitably produced, and as time goes by, more new raw materials are put into use, which makes waste plastics rise sharply. Because waste plastics are not easy to age and degrade at room temperature, white pollution is increasing day by day, causing serious damage to the ecological environment.

The output and consumption of plastic products in my country rank first in the world. The per capita annual consumption of plastics is about 3 kg (8 kg per capita in developed countries), and the degree of white pollution ranks fourth in the world. The market for recycled granules processed from discarded plastic products is in short supply, which can realize a virtuous cycle of resource utilization, which is of far-reaching significance. Agricultural film, convenience bags, cement bags, food packaging bags, woven bags and other film-based waste plastics are all sources of raw materials for recycled granules. Especially for paper mills that use waste paper as raw materials, 5-8% of solid waste will be generated per ton of waste paper, of which waste plastics such as polypropylene and polyethylene film are the main ones, accounting for 80-90%. A paper mill with a scale of 1 million tons of paper produces 50,000 to 80,000 tons of solid waste annually, including 40,000 to 70,000 tons of waste plastics. Recycling can generate huge economic benefits while reducing environmental pollution.

Due to the low bulk density, large volume, and complex composition of film-based waste plastics, it is especially difficult to crush, wash and purify, and consume a lot of water resources. The current recycling and regeneration field is mainly produced by individual households and small workshops, with simple equipment and small scale. Cause secondary environmental pollution.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a washing and purification system for the recycling and reuse of film-based waste plastics, and further provides a washing and purification method for the recycling and reuse of film-based waste plastics.

Technical solution: In order to solve the above technical problems, the washing and purification system for recycling and reusing film waste plastics provided by the present invention includes the first conveying equipment, the shredder, the second conveying equipment, and the drum washing machine according to the running direction of the material process. , multi-drum washing and separating device, sheet pump, oblique screw dehydrator, buffer silo, third screw conveyor, twin-screw impregnation machine, dryer, fourth conveying equipment and storage silo; the first conveying The discharge port of the equipment is facing the feed port of the shredder, the discharge port of the shredder is facing the feed port of the second conveying equipment, and the discharge port of the second conveying device is facing the drum type The feed port of the washing machine, the discharge port of the drum type washing machine is connected with the feed port in the multi-drum type washing and separating device, and a container is arranged below the discharge port of the multi-drum type washing and separating device , the tablet pump is arranged between the container and the inclined screw dehydrator, the input end of the tablet pump is arranged in the volume chamber of the container, and the output end of the tablet pump communicates with the feed port of the inclined screw dehydrator, The discharge port of the inclined screw dehydrator is connected with the feed port of the buffer silo, the discharge port of the buffer silo is connected with the feed port of the third screw conveyor, and the discharge port of the third screw conveyor is The feed port is connected with the feed port of the twin-screw impregnation machine, the discharge port of the twin-screw dip machine is connected with the feed port of the dryer, and the discharge port of the dryer is connected with the feed port of the fourth conveying equipment , the discharge port of the fourth conveying device communicates with the feed port of the storage bin.

Preferably, the first conveying equipment, the second conveying equipment and the fourth conveying equipment are chain conveyors or belt conveyors.

Preferably, the drum washing machine includes a body, a drum, and a drum driving device; the upper part of one side of the body is provided with a feed port, the other side is provided with a discharge port, and a washing chamber is provided in the body. The drum is set in the washing chamber and is driven to rotate by the drum driving device; the bottom of the body below the position of the drum is in the shape of an inverted frustum; the end of the body adjacent to the feed inlet is provided with an upper water inlet, The bottom of the inverted frustum-shaped lower cone mouth is provided with a pipe body connected to the lower cone mouth, and the side wall of the pipe body is provided with a lower water inlet; the bottom of the pipe body is provided with a sediment pipe. The upper end is provided with an upper slag discharge valve, and the lower end is provided with a lower slag discharge valve. The drum washing machine with this structure can enter water through the lower water inlet to form an upward water flow, and the thrust of the upward water flow will effectively reduce the downward sedimentation of materials with a lighter specific gravity, and only make heavy impurities with a heavier specific gravity such as metal objects, stones, etc. Sinking into the sediment pipe can effectively remove heavy impurities in the material, and greatly reduce the loss that is easily caused by the material in the process of washing and separating impurities.

Preferably, the multi-drum type washing and separating device includes a body, the upper part of one end of the body is provided with a feed port, the other end is provided with a discharge port, a washing chamber is provided in the body, and a rotary drum is provided in the washing chamber. Drum, two or more drums are arranged in sequence between the feed inlet and the outlet; the bottom of the machine body is in the shape of multiple inverted frustums juxtaposed, and the positions of the inverted frustums correspond to the positions of the drums one by one. And located below the corresponding drum position; the end of the body adjacent to the feed port is provided with an upper water inlet, and the bottom of the body bottom is equipped with a corresponding lower cone mouth that communicates with the lower cone mouth. The pipe body, the side wall of each pipe body is equipped with a lower water inlet; Lower the dump valve. As a further preference of this preferred solution: each lower water inlet of the multi-drum washing and separating device is correspondingly provided with a flow rate control device, each of the pipes is correspondingly provided with a flow meter, and the upper discharge valve and The corresponding lower discharge valve is an automatic valve that opens and closes alternately at intervals. The multi-drum type washing and separating device can simultaneously inject washing water through the upper and lower water inlets, and alternately open and close the upper and lower discharge valves, and use the different specific gravity of different materials in the mixed material to control the injection of each lower water inlet. The upward flow rate of washing water effectively washes and separates different materials with different specific gravity. Further, the progressive separation and incremental deposition effect of the mixed material can be obtained by configuring the ascending flow rate of the washing water injected into each of the lower water inlets in descending order. At the same time, the water flow rate can be controlled more precisely through the flow rate control device and the flow meter, and the automatic valve can automatically accumulate and unload the material, effectively ensuring the continuity of production.

Preferably, the helical screw dehydrator includes a helical shell, and a screw driven by a screw driving device is arranged inside the helical shell, and the helical shell and the internal helix are inclined from low to high along the material conveying direction, and the helical The two ends of the shell are respectively the slanted lower end of the shell and the slanted upper end of the shell. The upper part of the shell is located at the slanted lower end of the shell. mouth, the lower part of the spiral casing is provided with a filter screen in parallel.

The buffer silo can be a conventional reaction silo in the field, and as a further improvement of the present invention, a uniform-feeding buffer silo is preferred. The uniform blanking type buffer silo includes a silo body and a uniform blanking device, the top of the silo body is provided with a feed port, and the bottom of the silo body is provided with a blanking port; the uniform blanking device includes a shell, and the inside of the shell There is a discharge screw, and the lower part of one side of the shell is provided with the discharge port of the reaction chamber. The feed port of the uniform blanking device is the discharge port at the bottom of the reaction chamber body; the discharge screw includes a screw shaft and a The screw blade arranged on the screw shaft, the position of the screw shaft above the discharge port is fixed with a uniform blanking ring, and the uniform blanking ring is consistent with the central axis of the screw shaft; the uniform blanking ring It includes a pipe body and multi-threaded blades. The multi-threaded blades are fixedly connected to the outer wall of the pipe body. The helical blades on the material auger rotate in the same direction. As a further improvement of the present invention, the bin body of the uniform blanking type reaction bin is a trapezoidal square bin; the uniform blanking device includes more than two discharge screws, and each discharge screw includes a screw shaft and a screw blade, The screw blade is a variable pitch screw blade whose pitch gradually changes from small to large along the conveying direction; the screw shaft of each discharge screw is fixed at the position above the discharge port, and a uniform blanking ring is fixed, and each uniform blanking ring The central axis of the corresponding screw shaft is consistent, and the multi-threaded blades on each uniform blanking ring are in the same direction as the screw blades on the corresponding discharge screw; the two or more discharge screws are driven independently, adjacent to each other. The screw shaft of the discharge screw rotates in reverse. The uniform blanking type reaction chamber can realize uniform blanking through the uniform blanking ring, which is conducive to the stable production of downstream pulping equipment, and the load fluctuation range is reduced from more than doubled to within 10~15%, reducing the equipment failure rate , Improve equipment reliability and stabilize slurry quality. On this basis, more than two discharge augers can be further rotated in reverse, so that the material can flow more evenly under the joint push of two counter-rotating, especially inwardly rotating, spiral blades on the adjacent discharge auger. It moves forward, and then it is broken up by the stirring of the uniform drop ring, and it is continuously and evenly dropped from the discharge port to the downstream equipment. The variable pitch design of the helical blades on the discharge screw can make the material gradually transition from the full state to the loose state along the conveying direction of the screw shaft during the conveying process, which improves the efficiency and reduces the load and wear of the screw.

Preferably, the twin-screw impregnation machine in this system is as described in the Chinese patent application titled "A twin-screw impregnation machine" filed on September 11, 2012 with application number 201210332112.8 and publication number CN 102864669 A. described, the entire contents of which are hereby incorporated by reference. It can also be as described in the Chinese patent application entitled "A Twin-screw Impregnating Machine" with the authorization number ZL 201220458032.2 filed on September 11, 2012, the entire contents of which are hereby incorporated by reference. The above-mentioned twin-screw impregnation machine includes a frame and a motor arranged on the frame, a gear box, a movable drum gear coupling, a barrel and two screws, and the motor passes through a gear box and a movable The drum-shaped gear coupling is connected with two screw rods, and the two screw rods are parallel to each other and rotatably arranged in the barrel. One end of the barrel is provided with a material inlet, and the other end is provided with a material outlet. ; The screw is sequentially provided with a first conveying helical sleeve, a first extruding helical sleeve, a second conveying helical sleeve, a second extruding helical sleeve, a third conveying helical sleeve and a third extruding helical sleeve along the conveying direction, The helical directions of the first, second, and third conveying helical sleeves are opposite to those of the first, second, and third extruding helical sleeves, and the pitch of the first conveying helical sleeves gradually decreases along the conveying direction. Small; the lower part of the barrel is provided with a waste liquid hole; the first, second, and third extruded helical sleeves have grooves on the ribs; the barrel is split up and down, including symmetrical The connected upper half barrel fixedly arranged on the frame and the openable and closable lower half barrel connected on the frame. Preferably, the upper part of the barrel is provided with a liquid injection hole corresponding to the third conveying screw sleeve.

Dryer wherein can select this area conventional dryer for use, preferably mesh belt type dryer. The mesh belt dryer includes a case and a multi-layer dryer mesh belt device; the upper part of the case is provided with a feed port, and the bottom is provided with a discharge port; the multi-layer dryer mesh belt device includes a multi-layer horizontally arranged In the vertical direction, the first and last sections of the multi-layer conveyor belt are staggered, and along the material conveying direction, the head end of the next layer of conveyor belt protrudes from the tail end of the upper layer of conveyor belt; Above the head end of the highest conveyor belt, the discharge port is located below the tail end of the lowest conveyor belt; several hot air fans and some dehumidification fans are arranged around the chassis, and the hot air fans pass through the air duct and the air duct It is connected with the air inlet and air outlet provided on the mesh belt device of the multi-layer dryer, and the humidity exhaust fan is connected with the moisture discharge port provided on the mesh belt device of the multi-layer dryer through the moisture exhaust pipe.

In order to solve the above technical problems, the present invention provides a washing and purification method for recycling and reusing film-based waste plastics, which uses the above-mentioned recycling and reusing washing and purification system for film-based waste and old plastics. The method includes:

①Material preparation section:

The material is conveyed by the first conveying equipment to the shredder and crushed into pieces; then conveyed by the second conveying equipment to the drum washing machine, adding washing water to adjust the concentration to 3~5% for washing, sediment, and removal of mixed materials Heavy impurities in;

②Washing and separation section:

The washed water-containing material output from the material preparation section is transported to the multi-drum washing and separating device, and the water-containing paper and plastic materials are washed and separated by using the difference in specific gravity between the water-containing paper and plastic materials mixed in the film-type waste plastics. , the water-containing paper sheets are discharged from each sinking pipe, and the plastic sheets are moved forward to the discharge port, and then pumped by the sheet pump to the oblique screw dehydrator to further remove residual impurities and dehydrate. Residual impurities and water pass through the oblique spiral The screen mesh of the dehydrator is discharged;

③Mechanical kneading evenly:

The dehydrated plastic sheets output from the re-washing and separation section are conveyed to the buffer silo; the material output by the discharge screw of the buffer silo is conveyed to the twin-screw impregnation machine by the third screw conveyor, and in the twin-screw impregnation machine It is sheared and kneaded into small flakes and agglomerated particles, and the free water in the material is squeezed out at the same time;

④ Dry storage section:

The plastic material sheets output by mechanical kneading are conveyed to the dryer for hot air drying, and then conveyed to the storage bin by the fourth conveying equipment for storage.

Preferably, the ② washing and separating section is: transporting the mixed water-containing paper sheets, plastic sheets and water-washed film waste plastics output from the ① material preparation section to the multi-drum washing and separating device, from which the multi-drum washing and separating When washing water is injected into the upper water inlet of the device, washing water is injected from each lower water inlet at the same time, and the upward flow velocity of the washing water injected from each lower water inlet is set so that the impulsive force of the upward water flow in each pipe body is smaller than the weight and weight of the paper pieces in the washing water. The difference in buoyancy is greater than the difference between the gravity and buoyancy of plastic sheets in the washing water; the materials are washed, separated and broken up by multiple drums rotating in the same direction, and the upper and lower discharge valves are alternately opened and closed to discharge The water-containing paper sheets deposited in each sinking tube; the plastic sheets are forwarded to the discharge port by multiple drums rotating in the same direction, and then transported to the oblique screw dehydrator to further remove residual impurities and complete dehydration. Impurities and water are discharged through the screen mesh of the oblique screw dehydrator. Preferably, in the ② washing and separating section, washing water with an upward flow velocity of 0.01m/s-0.3m/s is injected from each lower water inlet of the multi-drum washing and separating device. The above preferred method can further remove light impurities mixed in the material, such as water-containing paper sheets with a specific gravity greater than 1 sinking gradually in the water flow slowly ascending in each tube body of the multi-drum type washing and separating device, and plastics with a lighter specific gravity The material floats in the washing water and is transferred to the output direction with the rotation of the drum. Under the action of the upward water flow, the plastic material rarely enters the pipe body from the lower cone ports, and even if it falls, it will be slowly upward. Flush back into the washing chamber of the body; finally the plastic sheets are moved forward by the drum to the discharge port, while the water-containing paper sheets settle and accumulate in each sinking tube, and are opened and closed alternately through the upper discharge valve and the lower discharge valve discharge.

In order to prevent the mixed material from entering the washing chamber, it has not yet been fully absorbed and moistened, nor has it been fully washed and dispersed, so a large amount of it will fall into the sinking tube through the lower cone mouth and tube body in the front row, so that the obtained Most of the deposited and separated materials are still in a semi-mixed state, and the cleanliness cannot meet the requirements. Therefore, as a further improvement of the method invention, in the ②washing and separating section, along the horizontal conveying direction of the mixed material of the multi-drum washing and separating device, the upward flow velocity of the washing water injected from each lower water inlet decreases successively. Because the upward flow velocity of the first lower water inlet is relatively large, the momentum of the upward water flow is relatively large. It enters the washing chamber and is washed and dispersed by the first drum, and a small part is absorbed, moistened, dispersed and separated. A relatively sufficient water-containing paper sheet can gradually sink through the slowly ascending water flow in the first tube body, while the semi-mixed material cannot sink; it contains plastic sheets with light specific gravity and water-containing paper sheets that have not been fully moistened The mixed materials are mixed and floated in the washing water, and are sent to the washing control area of the subsequent drum to continue washing and breaking up, further absorbing water, moistening and dispersing more fully, and the materials in the semi-mixed state gradually decrease, and the water injected into each lower water inlet The upward flow rate of the washing water decreases successively, which can make the gradually increasing moistened, broken up, and separated water-containing paper sheets gradually sink through the subsequent tubes, so as to obtain better progressive separation effect and incremental deposition effect.

Preferably, the hot air of the dryer in the (4) dry storage section is indirectly heated by a steam pipeline, and the steam pressure is 0.4-0.6 MPa. Another preference is that the hot air of the dryer in the ④ dry storage section is heated by electricity.

Preferably, the sediment impurities obtained after washing by the drum washing machine in the ① material preparation section enter the solid waste treatment system, and the water-containing paper sheets in the ② rewashing and separation section are discharged through the sinking pipe of the multi-drum washing and separating device into the solid waste treatment system In the waste paper repulping recovery system, the residual impurities and water discharged through the mesh of the filter plate of the oblique spiral dewatering machine enter the water treatment system, and are recycled to the washing process after being purified by precipitation; The free water discharged from the drainage filter enters the water treatment system, and after being purified by sedimentation, it is recycled for the washing process.

Beneficial effects: In the washing and purifying system and washing and purifying method for recycling and reusing film waste plastics provided by the present invention, the shredder is used to cut waste materials by mechanical shearing, and then the sediment is initially washed to remove heavy impurities, and then separated by multi-drum washing. The device uses multi-stage drum washing, and controls the upward flow rate of the washing water injected into each lower water inlet to effectively remove light impurities mixed in the material or separate different materials with different specific gravity by washing, and then use the twin-screw impregnation machine. The obtained plastic sheet is sheared and kneaded evenly into small pieces and agglomerated granules, and stored dry for future use. The method and system can realize the comprehensive utilization of solid waste in paper mills, the recycling of waste paper fibers and waste plastics, and can realize automation and large-scale industrial production, and can radically solve the problem of secondary environmental pollution caused by small-scale decentralized processing. It can reach more than 90%, and the washing water consumption can be reduced by 50-80% through the recycling of washing water. While reducing environmental pollution, it ensures the continuity of production and saves production space, which has significant significance.

Furthermore, the washing and purification system provided by the present invention can adopt a drum washing machine to form an upward water flow through the lower water inlet, effectively reducing the downward precipitation of materials with lighter specific gravity, and only making heavy impurities such as metals with heavier specific gravity It can effectively remove the heavy impurities in the material, and greatly reduce the loss that is easily caused by the material in the process of washing and separating impurities.

Furthermore, the washing and purification system provided by the present invention can adopt a uniform blanking type buffer silo to realize uniform blanking through the uniform blanking ring, which is conducive to the stable production of downstream pulping equipment, and the load fluctuation range is more than doubled from the original Reduced to within 10~15%, reducing equipment failure rate, improving equipment reliability and stabilizing slurry quality;

Furthermore, the washing and purification system provided by the present invention can use the hot air of a mesh belt dryer to dry plastic sheets, saving production space and improving energy efficiency.

Furthermore, in the washing and purification system and method provided by the present invention, in the multi-drum washing and separating device adopted, the progressive flow rate of the mixed material can be obtained by configuring the ascending flow rate of the washing water injected into the lower water inlets in descending order. Separate and incremental deposition effects. The water flow rate can also be controlled more precisely through the flow rate control device and the flow meter, and the automatic valve can automatically accumulate and unload the material, effectively ensuring the continuity of production.

Description of drawings

Figure 1 is a schematic structural view of a washing and purification system for recycling and reusing film-based waste plastics;

Fig. 2 is the structural representation of drum type washing machine;

Fig. 3 is the left view of Fig. 2;

Fig. 4 is the structural representation of multi-drum washing and separating device;

Fig. 5 is the left view of Fig. 4;

Fig. 6 is the structural representation of drum in multi-drum washing and separating device;

Fig. 7 is a structural schematic diagram of an oblique spiral dehydrator;

Fig. 8 is a schematic structural view of a uniform blanking type buffer silo;

Fig. 9 is a schematic structural view of the uniform blanking ring in the uniform blanking type buffer silo;

Fig. 10 is a schematic diagram of the structure of the uniform blanking device configured with two discharge screws in the uniform blanking type buffer silo;

Fig. 11 is the structural representation of mesh belt dryer;

FIG. 12 is a top view of FIG. 11 .

detailed description

The present invention will be further described below with reference to the accompanying drawings, system implementations and method embodiments.

As shown in Figure 1, the washing and purification system for the recovery and reuse of film-based waste plastics includes a first conveying device 1, a shredder 2, a second conveying device 3, a drum washing machine 4, and multiple Drum type washing and separating device 5, tablet pump 6, oblique screw dehydrator 7, buffer bin 8, third screw conveyor 9, twin-screw impregnation machine 10, dryer 11, fourth conveying equipment 12 and storage bin 13. The discharge port of the first conveying device 1 is facing the feed port of the shredder 2, and the discharge port of the shredder 2 is directly facing the feed port of the second conveying device 3, and the second The discharge port of the conveying equipment 3 is facing the feed port of the drum washing machine 4, and the discharge port of the drum wash machine 4 is communicated with the feed port in the multi-drum washing and separating device 5, and the A container is arranged below the discharge port of the multi-drum type washing and separating device 5, and the tablet pump 6 is arranged between the container and the oblique screw dehydrator 7, and the input end of the tablet pump 6 is arranged in the volume chamber of the container Inside, the output end of tablet pump 6 communicates with the feed port of oblique spiral dehydrator 7, and the discharge port of described helical dehydrator 7 communicates with the feed port of buffer hopper 8, and the feed port of described buffer hopper 8 The discharge port is communicated with the feed port of the third screw conveyor 9, the discharge port of the third screw conveyor 9 is connected with the feed port of the twin-screw impregnation machine 10, and the discharge port of the twin-screw impregnation machine 10 is The mouth is communicated with the feed port of the dryer 11, and the discharge port of the dryer 11 is communicated with the feed port of the fourth conveying equipment 12, and the discharge port of the fourth conveying equipment 12 is connected with the feed port of the storage bin 13. The feed port is connected.

Wherein, the first conveying equipment 1 , the second conveying equipment 3 and the fourth conveying equipment 12 are chain conveyors or belt conveyors. The crushing mechanical structure of the shredder 2 is composed of a fixed knife fixed on the casing and two relatively counter-rotating knife rollers. The shearing pair formed between the fixed knife and the fixed knife cuts the material into pieces of a certain size. The knife roller is composed of a shaft with a spline or a hexagonal section in the middle and a cutter head mounted on the shaft in series. It can be adjusted by The thickness of the cutter head is used to adjust the size of the cut material; the shredder can be configured with a single cutter roller structure, or a double cutter roller or multi cutter roller structure.

Drum type washing machine 4 wherein can be selected conventional drum type washing machine in this field, provides a kind of specific implementation mode here, as shown in Figure 2 and Figure 3, this drum type washing machine comprises body, and drum 402 , drum driving device 404; the upper part of one side of the body is provided with a feed port 401, the other side is provided with a discharge port 403, a washing chamber is provided in the body, and the drum 402 is located in the washing chamber and subjected to The drum driving device 404 drives the rotation; the bottom of the machine body below the position of the drum 402 is in the shape of an inverted truncated cone; The bottom of the cone mouth is provided with a pipe body connected with the lower cone mouth, and the side wall of the pipe body is provided with a lower water inlet 407; the bottom of the pipe body is provided with a sediment pipe 405, and the upper end of the sediment pipe 405 is provided with an upper The slag discharge valve 408 is provided with a lower slag discharge valve 409 at the lower end. When working, the material broken into pieces by the shredder enters the feed port 401 of the drum washing machine, the washing water is added from the upper water inlet 406 and the lower water inlet 407, and the drum 402 is driven by the drum driving device 404 and continuously Rotate slowly, after the tablet enters the washing area, the washed tablet is continuously pulled out through the discharge port 403 through the rotation of the drum 402, and heavy impurities such as metal objects and stones sink into the sediment pipe 405; Open the valve 408 and close the lower slag valve 409 to facilitate the sedimentation of the slag into the slag pipe 405. When the slag needs to be discharged, the upper slag valve 408 is closed and the lower slag valve 409 is opened to discharge the slag, and then the upper slag valve 408 Open again, the lower slag unloading valve 409 is closed again, and the upper and lower slag unloading valves are closed and opened alternately to realize the sediment, which enters the solid waste treatment system after being discharged. In this structure, since the water entering the lower water inlet 407 will form an upward flow, the thrust of the upward flow can effectively reduce the downward sedimentation of materials with a lighter specific gravity, but heavy impurities such as metal objects and stones with a heavier specific gravity will still sink into the structure. The sediment pipe can effectively remove the heavy impurities in the material, and greatly reduce the loss easily caused by the material in the process of washing and separating impurities.

As shown in Figure 4, the multi-drum type washing and separating device 5 wherein includes a body 520, the upper part of one end of the body 520 is provided with a feed port 510, and the other end is provided with a discharge port 530, and a washing chamber is provided in the body 520 , the washing chamber is provided with drums, and three drums are arranged in sequence between the feed port and the discharge port, which are respectively the first drum 541, the second drum 542 and the third drum 543; The shape of the bottom of the machine body 520 is three inverted truncated cones arranged side by side. The positions of the inverted truncated cones correspond to the positions of the drums one by one, and are located below the corresponding positions of the drums; Frustoconical. One end of the body 520 adjacent to the feed port 510 is provided with an upper water inlet 550, and the bottom of the body 520 is provided with a pipe connected to the lower cone mouth correspondingly below each inverted frustum-shaped lower cone mouth. A pipe body 561, a second pipe body 562 and a third pipe body 563; the side wall of the first pipe body 561 is provided with a first lower water inlet 571, and the bottom of the first pipe body 561 is provided with a first sinking pipe 581. The upper end of a sinking pipe 581 is correspondingly provided with a first upper discharge valve 591, and the lower end is correspondingly provided with a first lower discharge valve 599; the side wall of the second pipe body 562 is provided with a second lower water inlet 572, and the second pipe body The bottom of the 562 is provided with a second sinking tube 582, the upper end of the second sinking tube 582 is correspondingly provided with a second upper discharge valve 592, and the lower end is correspondingly provided with a second lower discharge valve 598; the side wall of the third pipe body 563 A third lower water inlet 573 is provided, and a third sinking pipe 583 is provided below the third pipe body 563. The upper end of the third sinking pipe 583 is correspondingly provided with a third upper discharge valve 593, and the lower end is correspondingly provided with a third Lower dump valve 597. Of course, it can also be configured as 4 drums, 5 drums or other numbers of drums according to needs, and the corresponding pipe body, lower water inlet, sinking pipe, upper discharge valve, and lower discharge valve are also the same Quantity and positional relationship.

Each of the lower water inlets is correspondingly equipped with a flow rate control device, each of the pipes is correspondingly equipped with a flow rate meter, and the upper discharge valve and the corresponding lower discharge valve are automatic valves that open and close alternately at intervals. The alternate opening and closing of the lower unloading valves can be set as follows: firstly open each upper unloading valve and close each lower unloading valve for a period of time to deposit the first type of material in the sinking pipe, then close each upper unloading valve and Open each lower discharge valve to discharge the first type of material from the sinking pipe, then open each upper discharge valve and close each lower discharge valve to deposit materials for a period of time, then close each upper discharge valve and open each The lower unloading valve discharges the material, ..., repeating this alternately at intervals. The body 520 is fastened together by the detachable upper shell and the lower shell through bolt connection, and each drum is installed in the washing chamber inside the upper shell and the lower shell, supported by bearings, and the gears are decelerated. The motor is connected with the input shaft of each drum and drives its rotation respectively. The drums are driven by gear reduction motors to rotate in the same direction, and the gear reduction motors adopt variable frequency speed regulation motors. As shown in Figure 5, the first drum 541 is supported by a bearing support 547 and a bearing support 548, and is decelerated by a gear. The motor 549 drives the rotation.

As shown in Figure 6, each drum includes a runner 306 and 5 sets of blade groups arranged sequentially along the axial direction of the runner, namely the first blade group 301, the second blade group 302, the third blade group 303, The fourth vane group 304 and the fifth vane group 305, each vane group includes several vanes uniformly distributed along the circumferential direction of the runner, and the gear reduction motor drives the runner 306 fixedly connected on the input shaft to rotate through the input shaft 307 . These 5 sets of blade groups have the same feeding direction along the tangential direction of the runner; the first blade group 301 and the fifth blade group 305 located outside the axial direction of the runner are opposite to each other in the feeding direction along the axial direction of the runner; The second blade group 302 on the inner side of the axial direction is opposite to the first blade group 301 adjacent to it along the material direction of the axial direction of the runner; the third blade group 303 located on the axial inner side of the runner is opposite to the second The padding direction of the blade group 302 along the axial direction of the runner is the same; the feeding direction of the fourth blade group 304 located on the axial inner side of the runner and the third blade group 303 adjacent to it along the axial direction of the runner are opposite; The fifth blade group 305 on the inner side of the runner axis is opposite to the fourth blade group 304 adjacent thereto in the direction of material shifting in the runner axial direction. Of course, the arrangement direction of the blades on each blade group can also be flexibly configured according to needs to obtain the required direction of feeding. In this way, the first aspect increases the washing and breaking up effective area of the drum, the second aspect gathers the mixed material to the washing and breaking up effective area, the third aspect can make the water flow generate turbulent flow more fully and balance washing and breaking up the mixed material, and the fourth aspect Through the mutual cancellation of the centrifugal force generated by the rotation of each blade group on the runner, it plays the role of self-balancing axial force, improves the energy efficiency ratio and stability of the device operation, and prolongs the life of the device.

The oblique spiral dehydrator 7 can be a conventional oblique spiral dehydrator in the field, and a specific implementation form is given here, as shown in Figure 7, the oblique spiral dehydrator includes a spiral shell 602, and the spiral shell 602 is equipped with a receiving The screw driving device 604 drives the rotating screw 603. The screw housing 602 and its internal screw 603 are inclined from low to high along the material conveying direction. The two ends of the screw housing 602 are the lower end and the upper end of the housing respectively. The casing is provided with a feed inlet 601 at the upper part of the inclined lower end of the casing, a drain outlet 607 is arranged at the lower part of the inclined lower end of the casing, and a discharge port 605 is arranged at the lower part of the inclined upper end of the casing. The lower part of the filter screen plate 606 is arranged in parallel. When working, the materials and water washed by the drum washing machine are pumped to the feed port 601 of the helical screw dehydrator by the tablet pump, the screw 603 is driven to rotate by the driving device 604, and the material is lifted by the screw 603 and transported to the discharge Port 605 exits. The washing water and residual impurities are discharged through the meshes of the filter screen plate 606 and discharged into the water treatment system through the drain 607, and then circulated back to the washing process after being purified by precipitation.

The buffer silo 8 can be a conventional silo in the field, preferably a uniform drop type buffer silo. As shown in Figure 8,

The uniform blanking buffer silo selected in this embodiment includes a silo body 1010 and a uniform blanking device, the silo body 1010 is a trapezoidal square silo, the top of the silo body is provided with a feed port 1020 of the reaction chamber, and the bottom of the silo body 1010 is provided with Blanking port; the uniform blanking device includes a housing, and a discharge screw is provided in the housing, and the discharge screw includes a screw shaft 1040 and a screw blade 1050 arranged on the screw shaft; the screw shaft 1040 of the discharge screw is connected to the The motor transmission connection on one side of the housing is connected, and the lower part of the other side of the housing is provided with the discharge port 1030 of the reaction chamber. 1040 is located above the discharge port 1030 and is fixed with a uniform blanking ring 1060; the structural diagram of the uniform blanking ring 1060 is shown in Figure 9, including a pipe body 1061, and the outer wall of the pipe body 1061 is fixedly connected with a multi-thread thread blade 1062 The pipe body 1061 of the uniform blanking ring is connected to the screw shaft 1040 by welding or bolt fastening, and the uniform blanking ring 1060 is consistent with the central axis of the screw shaft 1040; the rotation direction of the multi-threaded blade 1062 It is consistent with the spiral blade 1050 on the discharge spiral. Of course, the uniform blanking device of the reaction chamber can also include two such independently driven discharge screws, as shown in Figure 10, each discharge screw includes a screw shaft and a screw blade, and the screw blade is a The variable-pitch helical blades whose direction pitch gradually changes from small to large; the screw shaft of each discharge screw above the discharge port is fixed with a uniform blanking ring, and each uniform blanking ring corresponds to the central axis of the screw shaft Consistent, the multi-threaded blades on each uniform blanking ring and the helical blades on the corresponding discharge auger rotate in the same direction; the screw shafts of the two discharge augers rotate in opposite directions. Under this configuration, the material is pushed forward more evenly by the two counter-rotating, especially anti-inwardly rotating, spiral blades on the adjacent discharge screw, and then dispersed by the uniform blanking ring. Continuously and evenly drop from the discharge port to the downstream equipment; the variable pitch design of the screw blades on the discharge screw can make the material gradually transition from the full state to the loose state along the direction of the screw axis during the conveying process, improving efficiency and reducing the operating load of the screw and wear and tear. When working, the slurry is continuously fed into the reaction chamber body 1010 from the reaction chamber inlet 1020 at the top of the reaction chamber by the upstream conveying equipment. After meeting the residence time requirement of the process design, the material filling rate in the chamber is 70-80%. When the discharge screw is filled with material, it is in a state of full compaction, and the slurry is in the shape of lumps in the spiral groove between the discharge spiral blades 1050; when the discharge screw at the bottom of the reaction chamber starts and rotates, the spiral groove The material that is full of lumps is continuously conveyed to the end of the discharge screw close to the discharge port 1030; the slurry close to the tail end of the discharge screw passes through the uniform blanking ring 1060 before falling, and passes through the even discharge ring 1060. After the threaded blade 1062 stirs and breaks up, it falls continuously and evenly to the downstream equipment.

Among them, the twin-screw impregnation machine, as described in the Chinese patent application titled "a twin-screw impregnation machine" with the application number 201210332112.8 and the publication number CN 102864669 A filed on September 11, 2012, all The contents including the figures are hereby incorporated by reference. It can also be as described in the Chinese patent application entitled "A Twin-screw Impregnating Machine" with the authorization number ZL 201220458032.2 filed on September 11, 2012, the entire contents of which are incorporated herein by reference including the accompanying drawings. The twin-screw impregnation machine includes a frame and a motor arranged on the frame, a gear box, a movable drum gear coupling, a barrel and two screws, and the motor passes through a gear box and a movable drum. The shape-tooth coupling is connected with two screw rods by transmission, and the two screw rods are parallel to each other and rotatably arranged in the barrel, one end of the barrel is provided with a material inlet, and the other end is provided with a material outlet; The screw is sequentially provided with a first conveying helical sleeve, a first extruding helical sleeve, a second conveying helical sleeve, a second extruding helical sleeve, a third conveying helical sleeve and a third extruding helical sleeve along the conveying direction. The helical directions of the first, second, and third conveying helical sleeves are opposite to those of the first, second, and third extruding helical sleeves, and the pitch of the first conveying helical sleeves gradually decreases along the conveying direction ; A homogenizing ring is provided between each conveying helical sleeve and the extruding helical sleeve; the lower part of the barrel is provided with a waste liquid hole corresponding to the output ends of the first and second conveying helical sleeves, and the waste liquid hole is provided There is a filter grate, that is, a drainage screen; the first, second, and third extruded spiral sleeves have grooves on the ribs; the barrel can be split up and down, including symmetrically connected fixed The upper half barrel arranged on the frame and the lower half barrel connected on the frame can be opened and closed. Further, the upper part of the upper half of the barrel is provided with a liquid injection hole corresponding to the third conveying screw sleeve. When working, the material is propelled towards the discharge port through two meshing and co-rotating screws. During the conveying process, due to the gradual decrease of the pitch of the first conveying screw sleeve, the material is gradually compressed and filled with the screw groove, and enters the reverse extrusion zone. Before the extruding helical sleeve, that is, at the first homogenizing ring, the extruding force reaches the maximum, and the material is strongly extruded. In this process, the material is extruded, sheared, and kneaded evenly to make the geometric size smaller; similarly, the second conveying spiral sleeve, the second extrusion spiral sleeve, the third conveying spiral sleeve and the third extrusion After extrusion, shearing, kneading and homogenization of the spiral sleeve, the material is sheared and kneaded into small pieces and pellets, and the free water in the material is squeezed out and discharged through the filter grate.

Dryer wherein can select this area conventional dryer for use, preferably mesh belt type dryer. As shown in Fig. 11 and Fig. 12, the mesh belt dryer selected in this embodiment includes a cabinet and a multi-layer dryer mesh belt device 603; the top of the cabinet is provided with a feed port, and the bottom is provided with a discharge port The multi-layer dryer mesh belt device 603 includes a multi-layer conveyor belt arranged horizontally, and the first and last sections of the multi-layer conveyor belt are staggered in the vertical direction. Along the material conveying direction, the head end of the next layer of conveyor belt extends Out of the tail end of the upper conveyor belt; the feed inlet is located above the head end of the highest conveyor belt, and the discharge port is located below the tail end of the lowest conveyor belt; several hot air fans 601 are arranged around the chassis And several dehumidifying blowers 602, described hot blast blower 601 is connected with the air inlet, the air outlet that is provided with on the mesh belt device 603 of multi-layer drier through air duct and air duct, and described dehumidifying blower 602 is connected with multiple through dehumidifying pipes The moisture outlet provided on the mesh belt device 603 of the layer dryer is connected.

The method for recycling, reusing, washing and purifying film-based waste plastics using the above-mentioned film-based waste plastic recycling washing and purification system, the specific implementation method is as follows:

Embodiment 1 : Recycling of agricultural mulch film waste plastics

The materials mainly composed of agricultural film waste plastics are conveyed by the first conveying equipment 1 to the shredder 2, and are crushed into pieces with a side length of 20~50mm; The drum washing machine 4 washes and removes harmful impurities such as metal objects, stones and sand mixed in the tablet through the sediment pipe, and the sediment enters the solid waste treatment system with a washing concentration of 3%; after washing, the tablet and water flow into the multi-rotation Drum type washing and separating device 5, while injecting washing water from the upper water inlet of the multi-drum type washing and separating device, inject washing water with an upward flow rate of 0.3m/s from each lower water inlet, wash again and separate out the Light impurities, such as paper, etc. Then the plastic tablet and water are pumped together by the tablet pump 6 to the inclined screw dehydrator 7 for dehydration, and fine impurities such as sediment and water are discharged through the screen mesh on the periphery of the inclined screw together, sent to the water treatment system, and purified by sedimentation The final water is recycled for the washing process, and the dehydrated plastic sheets are lifted and transported to the buffer silo 7, where the moisture content of the sheets in the buffer silo is lower than 25%; the washed plastic sheets are discharged through the buffer silo 8 The screw is pushed out of the warehouse and transported to the twin-screw impregnation machine 10 by the third screw conveyor 9. In the twin-screw impregnation machine 10, the material is squeezed and concentrated by two meshing and co-rotating screws, and then passes through three-stage extrusion and shearing successively. Knead the entire section, and be cut and kneaded into small pieces and aggregated particles. At the same time, the free water contained in the material is forcibly concentrated and squeezed out, and discharged through the drainage filter into the water treatment system. The water after precipitation and purification is recycled. in the washing process. When the material is extruded, sheared and kneaded, a large amount of frictional heat will be generated, the temperature of the material can reach 80~90°C, and the moisture content of the tablet will drop below 15%; The mesh-feed belt dryer 11 is used for hot air drying, and the drying air is heated by electricity; the dried tablet is sent to the storage bin 13 through the fourth conveying equipment 12, and is packaged and sold as a commodity or enters downstream equipment for mixing and granulation. In this embodiment, the comprehensive utilization rate of resource recovery is about 90%, and the washing water consumption is reduced by about 50-80% through the recycling of washing water.

In the above process, light impurities such as water-containing paper pieces obtained by washing and separating again with the multi-drum washing and separating device can be output to the waste paper repulping recovery system for recycling.

Example 2: Recycling of woven bag waste plastics

The materials mainly composed of woven bag waste plastics are conveyed to the shredder 2 by the first conveying equipment 1, and are crushed into pieces with a side length of 20~50mm; then the crushed pieces are conveyed to the Drum washing machine 4 washes and removes harmful impurities such as metal objects, stones and sand mixed in the tablet through the sediment pipe, and the sediment enters the solid waste treatment system with a washing concentration of 4%; after washing, the tablet and water flow into the multi- Drum type washing and separating device 5, when washing water is injected from the upper water inlet of the multi-drum type washing and separating device, washing water with an upward flow rate of 0.2m/s is injected from each lower water inlet, and the material containing Light impurities, such as paper, etc. Then the plastic tablet and water are pumped together by the tablet pump 6 to the inclined screw dehydrator 7 for dehydration, and fine impurities such as sediment and water are discharged through the screen mesh on the periphery of the inclined screw together, sent to the water treatment system, and purified by sedimentation The final water is recycled for the washing process, and the dehydrated plastic sheets are lifted and transported to the buffer silo 7, where the moisture content of the sheets in the buffer silo is lower than 20%; the washed plastic sheets are discharged through the buffer silo 8 The screw is pushed out of the warehouse and transported to the twin-screw impregnation machine 10 by the third screw conveyor 9. In the twin-screw impregnation machine 10, the material is squeezed and concentrated by two meshing and co-rotating screws, and then passes through three-stage extrusion and shearing successively. Knead the entire section, and be cut and kneaded into small pieces and aggregated particles. At the same time, the free water contained in the material is forcibly concentrated and squeezed out, and discharged through the drainage filter into the water treatment system. The water after precipitation and purification is recycled. in the washing process. When the material is extruded, sheared and kneaded, a large amount of frictional heat will be generated, the temperature of the material can reach 80~90°C, and the moisture content of the tablet will drop below 10%; The mesh belt dryer 11 is used for hot air drying, and the drying air is indirectly heated by a steam pipe with a steam pressure of 0.4~0.6MPa; the dried tablet is sent to the storage bin 13 through the fourth conveying device 12, and is packaged and sold as a commodity or imported Downstream equipment mixing and granulation. In this embodiment, the comprehensive utilization rate of resource recovery is about 93%, and the washing water consumption is reduced by about 50-80% through the recycling of washing water.

In the above process, light impurities such as water-containing paper pieces obtained by washing and separating again with the multi-drum washing and separating device can be output to the waste paper repulping recovery system for recycling.

Example 3: Recycling and comprehensive utilization of solid waste in paper mills

The paper mill solid waste materials mainly composed of waste paper, polypropylene, polyethylene and other film waste plastics are transported from the first conveying equipment 1 to the shredder 2, and are shredded into pieces with a side length of 20~50mm; and then The second conveying equipment 3 transports the crushed material to the drum washing machine 4 for washing, and removes harmful impurities such as metal objects, stones and sand mixed in the material through the sediment pipe, and the sediment enters the solid waste treatment system for washing. The concentration is 5%; after washing, the tablet and water flow into the multi-drum washing and separating device 5 together, and the washing water is injected from the upper water inlet and each lower water inlet of the multi-drum washing and separating device at the same time. In the horizontal conveying direction of the mixed material, the upward flow velocity of the washing water injected from each lower water inlet decreases successively, the first lower water inlet injects the washing water with an upward flow velocity of 0.3m/s, and the second lower water inlet injects an upward flow velocity of 0.2m /s of washing water, the third lower water inlet injects washing water with an upward flow velocity of 0.15 m/s, and uses the difference in specific gravity between the water-containing paper, plastic material and water to separate the water-containing paper and plastic material, and the water-containing paper enters each The sinking pipe is discharged and enters the waste paper fiber repulping recovery system; the plastic flakes and water discharged from the outlet of the multi-drum washing and separating device are pumped together by the flake pump 6 to the oblique screw dehydrator 7 for dehydration, and the mud Small impurities such as sand and water are discharged through the screen mesh on the periphery of the inclined spiral, and sent to the water treatment system, and the water after sedimentation and purification is recycled for the washing process; the dehydrated plastic sheets are lifted and transported to the buffer silo 7 , the moisture content of the sheet in the buffer silo is lower than 35%; the washed plastic sheet is pushed out of the silo through the discharge screw of the buffer silo 8 and is transported to the twin-screw impregnation machine 10 by the third screw conveyor 9. The material in the impregnating machine 10 is squeezed and concentrated by two meshing and co-rotating screws, and then passes through three stages of extrusion, shearing and kneading in turn, and is sheared and kneaded to form small pieces and pellets. At the same time, the material contains The free water is forcibly concentrated and squeezed out, and then discharged into the water treatment system through the drainage filter, and the water purified by sedimentation is recycled for the washing process. When the material is extruded, sheared and kneaded, a large amount of frictional heat will be generated, the temperature of the material can reach 80~90°C, and the moisture content of the tablet will drop below 25%; The mesh belt dryer 11 is used for hot air drying, and the drying air is indirectly heated by steam pipes, the steam pressure is 0.5MPa, and the air consumption is 350kg/t tablet; the dried tablet is sent to the storage bin 13 through the fourth conveying equipment 12 , sold as a packaged product or entered into downstream equipment for mixing and granulation. In this embodiment, the comprehensive utilization rate of resource recovery is about 96%, and the washing water consumption is reduced by about 50-80% through the recycling of washing water.

Embodiment 3 is a preferred embodiment, and it is an example to illustrate the separation of materials carried out in the multi-drum type washing and separating device with Embodiment 3: because the specific gravity of the paper sheet is greater than 1, and the waste and old plastic sheet of polypropylene, polyethylene film class The specific gravity is smaller than that of the paper, and the upward flow velocity of the washing water injected from each lower water inlet is set within 0.01m/s~0.3m/s (including 0.01m/s and 0.3m/s), which can make each tube The impulsive force of the upward water flow in the body is less than the difference between the gravity and the buoyancy of the paper sheet in the water, and is greater than the difference between the gravity and the buoyancy of the film-like waste plastic sheet in the water. The paper pieces and waste plastic pieces mixed together in this way are washed and broken up by multiple drums rotating in the same direction, and gradually separated in the washing chamber; Gradually sink down to the sinking tube, while the film-like waste plastic material floats on the water surface because it does not absorb water and has a light specific gravity, and is moved forward to the discharge port by multiple drums rotating in the same direction. In Embodiment 1 and Embodiment 2, the light impurities contained in the material, such as paper pieces, are washed and separated by the multi-drum washing and separating device, which is also the same principle.

The experiment was carried out under the washing condition that the outer circular velocity of the drum was 1m/s, the weight ratio of the dry mixed material to the washing water was 3:97, that is, the washing concentration was 3%. The upward flow velocity of water is set within 0.01m/s~0.3m/s, which can properly realize the effective separation of water-containing paper sheets and film plastic sheets, otherwise the upward flow velocity is too high, which will cause excessive pressure on the settled water-containing paper sheets. However, under the action of the upward water flow, the film-type waste plastic materials washed with the rotation of the drum seldom enter the pipe body from the lower cone ports, and even if they fall, they will be washed by the slowly upward water flow. Back in the washing cavity of the body, so there is no upward flow velocity or the upward flow velocity is too small, and the film and plastic sheet that has strayed into the pipe body with the water flow can not be effectively returned to the washing cavity and sent to the output direction. The difference in specific gravity between water-containing paper sheets, plastic sheets and water is fully utilized to realize efficient washing and separation of paper sheets and plastic film sheets.

The above embodiments do not limit the present invention, and various changes and modifications made by relevant workers within the scope of not departing from the technical idea of the present invention all fall within the protection scope of the present invention.

Claims (6)

1. A washing and purification method for recycling waste plastics such as films, characterized in that the method uses a washing and purification system for recycling waste plastics such as films. , second conveying equipment, drum washing machine, multi-drum washing and separating device, sheet pump, oblique screw dehydrator, buffer silo, third screw conveyor, twin-screw impregnation machine, dryer, fourth conveying equipment and storage silos; the method includes: ①Material preparation section: The material is conveyed by the first conveying equipment to the shredder and crushed into pieces; then conveyed by the second conveying equipment to the drum washing machine, adding washing water to adjust the concentration to 3-5% for washing, sediment, and removal of mixed materials Heavy impurities in; ②Washing and separation section: The washed water-containing material output from the material preparation section is transported to the multi-drum washing and separating device, and the water-containing paper and plastic materials are washed and separated by using the difference in specific gravity between the water-containing paper and plastic materials mixed in the film-type waste plastics. , the water-containing paper sheets are discharged from each sinking tube, and the plastic sheets are moved forward to the discharge port, and then pumped by the sheet pump to the inclined screw dehydrator for dehydration; ③Mechanical kneading evenly: The dehydrated plastic sheets output from the re-washing and separation section are conveyed to the buffer silo; the material output by the discharge screw of the buffer silo is conveyed to the twin-screw impregnation machine by the third screw conveyor, and in the twin-screw impregnation machine It is sheared and kneaded into small flakes and agglomerated particles, and the free water in the material is squeezed out at the same time; ④ Dry storage section: The plastic sheets output by mechanical kneading are conveyed to the dryer for hot air drying, and then conveyed to the storage bin by the fourth conveying equipment for storage; In the ②washing and separating section, along the horizontal conveying direction of the mixed material of the multi-drum washing and separating device, the upward flow velocity of the washing water injected from each lower water inlet decreases successively. 2. The method for recycling, washing and purifying thin film waste plastics according to claim 1, characterized in that: the ②washing and separating section is: washing the mixed water-containing paper sheets, plastic sheets and water output from the ① material preparation section. The post-film waste plastics are transported to the multi-drum washing and separating device, and the washing water is injected from the upper water inlet of the multi-drum washing and separating device while washing water is injected from each lower water inlet, and the washing water injected from each lower water inlet goes up The flow rate is set so that the impulsive force of the upward water flow in each pipe body is less than the difference between the gravity and buoyancy of the paper sheets in the washing water, and is greater than the difference between the gravity and the buoyancy of the plastic sheets in the washing water; Separating and breaking up materials, alternately opening and closing each upper discharge valve and each lower discharge valve to discharge the water-containing paper sheets deposited in each sinking tube; through multiple drums rotating in the same direction, the plastic sheets are moved forward to the discharge port, and then transported to the helical screw dehydrator to further remove residual impurities and complete dehydration. The residual impurities and water are discharged through the screen mesh of the helical screw dehydrator. 3. The method for recycling, washing and purifying thin-film waste plastics according to claim 1, characterized in that: in the ② washing and separating section, the upward flow rate of injection from each lower water inlet of the multi-drum washing and separating device is 0.01 m/s～0.3m/s washing water; the hot air of the drier in the ④dry storage section is indirectly heated by steam pipes. 4. The washing and purification method for recycling and reusing thin film waste plastics according to claim 1, characterized in that: the hot air of the drier in the ④ drying storage section is indirectly heated by steam pipes, and the steam pressure is 0.4-0.6 MPa. 5. The method for recycling, washing and purifying thin film waste plastics according to claim 1, characterized in that: the hot air of the drier in the ④ drying storage section is heated by electricity. 6. The method for recycling, reusing, washing and purifying thin-film waste plastics according to claim 1, characterized in that: the sediment impurities obtained after washing by the drum washing machine in the material preparation section of the ① enter the solid waste treatment system, and the ② is then In the washing and separating section, the water-containing paper sheets are discharged through the sinking pipe of the multi-drum washing and separating device into the waste paper repulping recovery system, and the residual impurities and water discharged through the filter plate mesh of the oblique screw dehydrator enter the water treatment system , after being purified by precipitation, it is recycled to be used in the washing process; the free water discharged through the drainage filter screen in the above ③ mechanical kneading and leveling section enters the water treatment system, and is recycled to be used in the washing process after being purified by precipitation.