JP2005349838A - Processing device for waste plastic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of unsteady feeding of waste plastics to a processing device due to a lot of films in the waste plastics which tend to cause a bridging in a hopper. <P>SOLUTION: The processing device for waste plastics, which feeds a waste plastic P containing a chlorinated polymer from a supply port 4a to a cylinder 4, heats up to a predetermined temperature after plasticizing, and discharges from an exhaust port 8, is composed as follows. A vent 10 is formed to the exhaust port 8 side of the cylinder 4, a drainage means 9 is prepared on the cylinder 4 near the supply port 4a, and a pushing means A equipped with pushing members 3 and 3A is prepared on the supply port 4a, so as to push, driven by driving means 2 and 2A, controlling the feed rate of the waste plastic P without plasticizing; thereby the waste plastic P is supplied to the cylinder 4 with increased bulk density. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a waste plastic processing apparatus, and more particularly to a waste plastic processing apparatus provided with a device for efficiently supplying waste plastic containing a chlorine-based polymer.

  Currently, more than 15 million tons of plastic are produced annually in Japan, of which approximately 9.5 million tons are discharged as waste plastic every year. These waste plastics have been treated by landfill or incineration, but in recent years from the viewpoint of difficulty in securing a final disposal site, environmental protection and effective use of resources, Attention is focused on reduction to low boiling point oil, that is, oil conversion, recovery of energy such as heat or electricity by combustion as thermal recycling, use as raw material for blast furnace, use as raw fuel for cement kiln, etc. It is summer.

  However, if the waste plastic contains a chlorinated polymer such as polyvinyl chloride (hereinafter referred to as “PVC”) or polyvinylidene chloride (hereinafter referred to as “PVDC”), hydrogen chloride or the like may be generated during combustion. Therefore, there are problems such as corrosion of the combustion furnace and reduction of the recovery rate of heat and electric energy, and further dioxins are generated.

  Several devices have been proposed to remove the chlorine causing these problems from waste plastics and to produce useful solid fuels. Examples of the first method include those described in Patent Document 1 (Japanese Patent No. 2648412), Patent Document 2 (Japanese Patent Laid-Open No. 9-310077), and Patent Document 3 (Japanese Patent Laid-Open No. 11-50072). . These first methods include a method of supplying waste plastic as it is to a processing apparatus, a method of supplying waste plastic as it is, a method of supplying it after crushing, and a method of supplying after removing foreign matters such as metal after crushing Furthermore, it is the method of supplying after removing crushing and a foreign material, wash | cleaning with water.

  Moreover, as a 2nd method, it describes in patent document 4 (Unexamined-Japanese-Patent No. 7-266339), patent document 5 (Unexamined-Japanese-Patent No. 7-256644), and patent document 6 (Unexamined-Japanese-Patent No. 7-112437). There is something. These second methods are methods of increasing the bulk density of waste plastic and then converting it to solid fuel by a volume reduction solidification device for waste plastic.

Furthermore, as a third method, there is one described in Patent Document 7 (Japanese Patent Laid-Open No. 10-138246). In this third method, the waste plastic processing apparatus is composed of a precompressor and a reactor, and the waste plastic introduced from the inlet is previously melted and compressed by the precompressor and supplied to the reactor. This is a solid fuel conversion method in which dechlorination is further performed by heating in a machine. Patent Document 7 (Japanese Patent Application Laid-Open No. 10-138246) also describes, as a conventional technique, that a crushed plastic is pushed into a processing apparatus by pressure due to the weight of the upper weight.
Japanese Patent No. 2648412 JP-A-9-310077 Japanese Patent Laid-Open No. 11-50072 JP-A-7-266339 JP-A-7-256644 JP-A-7-112437 JP 10-138246 A

  However, according to the first method, since the bulk specific gravity of the waste plastic is low as it is, the supply amount to the processing apparatus is reduced, and if the apparatus is enlarged and the screw diameter is not increased, the supply amount can be increased. There is a problem that there is no problem, which has caused an increase in the size of the processing apparatus and an increase in processing cost. In addition, waste plastic contains many films such as shopping bags and wraps, but these tend to cause bridging in the hopper of the processing apparatus, so that the supply of waste plastic to the processing apparatus becomes unstable. There was a problem.

  In the second method, waste plastic is conveyed by crushing, kneading (mixing), compressing, melting, and compacting with a pair of screws (shafts with spiral blades). Is supplied without being compressed in advance, and a pair of screws are used to melt not only compression but also crushing, crushing and kneading waste plastic, so that the kneading and melting action is sacrificed for the compression action. Inevitably, the structure becomes complicated and large.

  Furthermore, in the case of the third method, as in the second method, the waste plastic introduced from the inlet is melted and compressed in advance by a preliminary compressor having a pair of screws and supplied to the reactor. The compressor must be provided with not only a compression function but also a melting function, and the compression and action of waste plastic with low bulk specific gravity must be sacrificed, and the kneading and melting action must be sacrificed, and the structure is complicated and large. Turn into. As a result, there is a problem that the processing cost of waste plastic increases.

  In order to separate the compression function and the melting function of the waste plastic as much as possible, the present invention is provided with a pressing member dedicated for compression, and by giving an appropriate structure to each, the throughput is large as a whole, and The object is to provide a compact waste plastic treatment device.

The present invention has been made in view of such a conventional technical problem, and the configuration thereof is as follows.
The invention of claim 1 is a waste plastic processing apparatus in which waste plastic P containing a chlorinated polymer is supplied from a supply port 4a to a cylinder 4 and plasticized, then heated to a predetermined temperature and discharged from a discharge port 8. The vent 4 is provided between the supply port 4a and the discharge port 8 of the cylinder 4, the drainage means 9 is provided in the cylinder 4 near the supply port 4a,
Pushing means A having pushing members 3 and 3A that push the waste plastic P without being plasticized while adjusting the feed amount by driving by the driving means 2 and 2A is provided in the supply port 4a, and the bulk density of the waste plastic P The waste plastic processing apparatus is characterized in that it is supplied to the cylinder 4 with a larger diameter.
The invention according to claim 2 is the waste plastic processing apparatus according to claim 1, wherein the push-in member 3 is a screw 3 that applies a propulsive force toward the supply port 4a.
The invention according to claim 3 is the waste plastic treatment apparatus according to claim 1, wherein the pushing member 3A is a piston 3A pushed toward the supply port 4a.

According to the waste plastic processing apparatus of the present invention, the following effects can be obtained.
Since the waste plastic push-in means capable of increasing the bulk density can be provided in the cylinder supply section, waste plastic can be supplied efficiently and stably. Moreover, since the pushing means can adjust the amount of waste plastic that is fed, it can be fed at a higher density according to the bulk specific gravity of the waste plastic that is the raw material, and the amount of feed can be matched to the conveying capacity of the cylinder. be able to.

  In this way, the waste plastic compression function is applied to the pushing means, and the compression function of the waste plastic by the cylinder is reduced and mainly the melting function is borne. It is possible to provide a waste plastic processing apparatus that is large in volume and compact. As a result, it can contribute to the reduction of the manufacturing cost of solid fuel.

  Since the pressing force is applied to the waste plastic in the vicinity of the supply port by the pressing means, dehydration is effectively performed. As a result, it is possible to satisfactorily prevent water from accumulating near the supply port of the cylinder, resulting in poor penetration of the waste plastic, and evaporation of moisture from adhering to the inner surface of the supply unit.

  FIG. 1 shows a first embodiment of a waste plastic treatment apparatus according to the present invention. The waste plastic treatment apparatus includes a preheating device B, a dechlorination device C, and an exhaust gas treatment device D as main components. The waste heating plastic pushing means A is attached to the preheating device B.

  The preheating device B mainly has a function of raising the waste plastic P containing a chlorinated polymer such as PVC or PVDC to a predetermined temperature after plasticizing and discharging it in a molten state. A cylinder 4 having an outlet 8 and a screw 6 rotatably provided in the cylinder 4 and driven to rotate by a motor 5 are provided. In addition, a slit 9 as a drainage means is formed in the inner bottom portion near the supply port 4a of the cylinder 4, and a vent 10 is formed near the discharge port 8 of the cylinder 4, and a heater 7 which is a heating means. Therefore, the cylinder 4 can be heated appropriately. The slit 9 has a plurality of through holes so as to prevent the waste plastic P from passing therethrough and to selectively discharge water. The discharge port 8 is given an opening area smaller than the cross-sectional area of the cylinder 4 and can compress the waste plastic P inside.

  The dechlorination apparatus C further heats the molten waste plastic that has been heated to a predetermined temperature in the preheating apparatus B, thermally decomposes the chlorine-based polymer to generate a chlorine compound, and converts the molten waste plastic and the chlorine compound into The cylinder 12 mainly has a function of separating, and has a supply port 12 a and a discharge port 16, and a screw 14 that is rotatably provided in the cylinder 12 and is rotationally driven by a motor 13. Further, a vent 17 is formed near the discharge port 16 of the cylinder 12, and the cylinder 12 can be appropriately heated by a heater 15 as a heating means. An exhaust gas treatment device D is connected to the vent 17 via an exhaust gas pipe 18.

  The supply port 12 a of the dechlorination device C and the discharge port 8 of the preheating device B are communicated with each other through a polymer pipe 11. Note that a cooling means and a cutter (not shown) are provided at the discharge port 16 of the dechlorination apparatus C.

  And the pushing means A which can push the waste plastic P continuously and automatically in the supply port 4a of the preheating apparatus B is provided. This pushing means A has a function of compressing the waste plastic P, and is for supplying the bulk plastic with a large bulk density. It does not have a function of plasticizing and melting the waste plastic P, and the supply port 4a. The screw 3 which is a pushing member which gives a driving force toward is provided. That is, a hopper-shaped supply portion 1 composed of a truncated conical cylinder that gradually decreases in diameter toward the supply port 4a is fixed to the cylinder 4, and an outer shape that gradually decreases in diameter toward the supply port 4a in the supply portion 1 The screw 3 having the above is attached to a single rotary shaft 3a, and the rotary shaft 3a and the screw 3 are rotationally driven by the motor 2 which is driving means, so that the feed amount can be adjusted. The external shape of at least the vicinity of the supply port 4a of the screw 3 is substantially matched without contacting the inner surface of the supply unit 1.

Next, the operation of the first embodiment will be described.
The waste plastic P is put into the preheating device B through the supply unit 1. The waste plastic P at the time of charging can be left in a discarded shape, but it is crushed to a predetermined size, specifically a size of 50 mm square or less, preferably a size of 20 mm square or less in order to increase the input amount. If so, the amount of pushing increases while reducing the load on the pushing means A. Further, it is preferable to remove in advance foreign matters such as metal such as aluminum and iron, glass, etc., because damage to the screw 3 of the pushing means A, the supply unit 1, the cylinder 4 and the screw 6 of the preheating device B is reduced. In addition, if waste plastic P washed with water after crushing and removing foreign matter is used, chlorine derived from salt can be removed, so not only the residual chlorine concentration in the waste plastic after dechlorination can be reduced, Since dirt, sand, etc. adhering to the waste plastic P can be removed, damage to the screw 3 of the pushing means A, the supply unit 1, the cylinder 4 of the preheating device B, and the screw 6 is reduced.

  The waste plastic P put into the supply unit 1 receives the propulsive force of the screw 3 driven by the motor 2 and is continuously and automatically sent from the supply port 4a to the cylinder 4 of the preheating device B. It is bitten into the screw 6 that is rotationally driven by the motor 5. Since the amount of waste plastic P fed can be easily increased or decreased by controlling the number of revolutions of the motor 2, the density is increased in accordance with the bulk specific gravity of the waste plastic P, and the conveying capacity of the screw 6 is increased. Can be sent together. The conveying capacity of the screw 6 can be adjusted by the number of rotations of the motor 5.

  When the waste plastic P used as a raw material contains water or is washed with water in advance, the water is squeezed out by the screw 6 and discharged from the slit 9 to the outside. Since the pressing force acts on the waste plastic P near the supply port 4a by the screw 3 of the pushing means A, dehydration is effectively performed. As a result, water accumulates in the vicinity of the supply port 4a of the cylinder 4 and the penetration property of the waste plastic P into the screw 6 becomes worse, or moisture evaporated by the heat of the heater 7 adheres to the inner surface of the supply unit 1 and corrodes. It is prevented well that it becomes the cause of.

  Since the cylinder 4 and the screw 6 are arranged horizontally, and the central axis (rotary shaft 3a) of the supply unit 1 and the screw 3 made of a truncated conical cylinder is arranged perpendicular to each other, the waste plastic P thrown into the supply unit 1 is The screw 3 is forcibly fed into the cylinder 4 while receiving its own weight while being pressed downward by the screw 3.

  The waste plastic P in the cylinder 4 is kneaded and transported by the screw 6 while being heated by the heater 7, plasticized, heated to a predetermined temperature, and melted from the discharge port 8 having a small cross-sectional area. Discharged in a state. The moisture remaining without being discharged from the slit 9 is discharged out of the system as steam from a vent 10 provided between the supply port 4 a and the discharge port 8.

  The molten waste plastic discharged from the discharge port 8 of the preheating device B is sent to the dechlorination device C via the polymer pipe 11. In the dechlorination apparatus C, the molten waste plastic is further heated by the heater 15 and is kneaded and transported by the screw 14 so that the chlorinated polymers such as PVC and PVDC in the waste plastic P are thermally decomposed. A chlorine-based compound is generated and separated into molten waste plastic and a chlorine compound. The separated chlorine compound is discharged out of the system from the vent 17 and sent to the exhaust gas treatment device D via the exhaust gas pipe 18 where it is rendered harmless. The molten waste plastic from which the chlorine compound has been removed is discharged from the discharge port 16 of the dechlorination apparatus C, cooled and cut, and used for various applications as a solid fuel. The conveying capacity of the screw 14 can be adjusted to the amount of molten waste plastic flowing from the polymer pipe 11 by adjusting the rotation speed of the motor 13.

  FIG. 2 shows a waste plastic pushing means A which is a main part of the second embodiment, and the same reference numerals are given to the same functional parts as those of the first embodiment. In this pushing means A, the hopper-shaped supply part 1 has a conical cylindrical part 1Ab that gradually expands upward, and a cylindrical part 1Aa that connects to the small-diameter end of the conical cylindrical part 1Ab. The portion 1Aa is connected and fixed to the supply port 4a, and the supply portion 1 is provided with one piston 3A that is a pushing member having a size that can be received in the cylindrical portion 1Aa.

  The piston 3A is driven by a double-acting air cylinder device 2A that is a driving means, and moves up and down between a conical cylindrical portion 1Ab position indicated by a solid line and a cylindrical portion 1Aa position indicated by a broken line. Since the amount of waste plastic P fed can be easily adjusted by controlling the lifting speed and lifting interval of the piston 3A by the air cylinder device 2A, the density is increased according to the bulk specific gravity of the waste plastic P, and The screw 6 can be fed in accordance with the conveying capacity.

  As a result, the waste plastic P introduced into the supply unit 1 is continuously and automatically pushed from the cone-shaped cylindrical part 1Ab into the cylindrical part 1Aa by the piston 3A that moves up and down. Is forcibly sent to the screw 6. As a result, the waste plastic P can be stably fed into the preheating device B as in the pushing means A using the screw 3 shown in FIG. Thereafter, as in the first embodiment shown in FIG. 1, the waste plastic P is dehydrated, plasticized, heated and dechlorinated to become a solid fuel.

  Since the cylinder 4 and the screw 6 are horizontally arranged, and the central axis of the piston rod 2Aa of the supply unit 1 and the air cylinder device 2A is perpendicularly arranged, the waste plastic P thrown into the supply unit 1 is moved by the piston 3A. It is forcibly fed into the cylinder 4 while receiving its own weight while being pressed downward.

Example 1
After collecting the collected waste plastic P of general urban system as a pretreatment by removing materials other than plastic such as metal, glass, etc., such as cans and bottles, a crusher manufactured by Horai (model: V03-480L ) Using S), it was crushed to a size of 20 mm or less, and washed and dehydrated by a washing / dehydrating machine (model: CFP-500) manufactured by Toyo Seiki Co., Ltd.

  This waste plastic P was fed into the preheating device B from the supply port 4a by the waste plastic pushing means A shown in FIG. The rotation speed of the screw 3 of the pushing means A was set to 500 rpm. A slit 9 is attached to the cylinder 4 of the preheating device B, and a biaxial screw 6 having a diameter of 44 mm is provided. The waste plastic P is plasticized by the preheating device B, heated to 220 ° C., and then passed through the polymer pipe 11 so that the screw 14 has a diameter of 174 mm. C. The maximum temperature of the molten waste plastic in the cylinder 12 of the dechlorination apparatus C was 350 ° C., and the residence time was 10 minutes. As a result, a solid fuel having a residual chlorine concentration of 0.2% by weight could be stably obtained at an extrusion rate of 70 kg / h for 6 hours.

Example 2
Waste plastic P that has been subjected to the same pretreatment as in the first embodiment is fed into the preheating device B from the supply port 4a by the waste plastic pushing means A shown in FIG. B and dechlorinator C. The speed of the piston 3A of the pushing means A is continuous for 3 seconds / stroke. As a result, a solid fuel having a residual chlorine concentration of 0.2% by weight could be stably obtained at an extrusion rate of 70 kg / h for 6 hours.

Comparative Example 1
Waste plastic that had been subjected to the same pretreatment as in Example 1 was supplied to the supply port (hopper) of the preheating device (B) of a biaxial screw type having a diameter of 44 mm while being naturally dropped to be plasticized and heated. Then, it processed by the same dechlorination apparatus (C) as Example 1. However, the slit 9 is not formed in the preheating device (B). The operating conditions of the preheating device (B) and the dechlorination device (C) are the same as in Example 1. As a result, the residual chlorine concentration fluctuates from 0.2 to 0.5% by weight, the extrusion rate is 20 to 30 kg / h, and 30 minutes after the start of operation, water is added near the supply port of the preheating device (B). Has accumulated, making it impossible to continue driving.

Schematic which shows the processing apparatus of the waste plastic which concerns on 1st Embodiment of this invention in a cross section. Schematic which shows the principal part of the waste plastic processing apparatus which concerns on 2nd Embodiment in a cross section.

Explanation of symbols

  1: Supply part, 1Aa: Cylindrical part, 1Ab: Conical cylinder part, 2: Motor (drive means), 2A: Air cylinder device (drive means), 2Aa: Piston rod, 3: Screw (pushing member), 3A : Piston (pushing member), 3a: rotating shaft, 4: cylinder, 4a: supply port, 6: screw, 8: discharge port, 9: slit (drainage means), 10: vent, 11: polymer piping, 12: cylinder , 14: screw, A: pushing means, B: preheating device, C: dechlorination device, D: exhaust gas treatment device, P: waste plastic.

Claims (3)

Waste plastic (P) containing chlorine-based polymer is supplied from the supply port (4a) to the cylinder (4), plasticized, heated to a predetermined temperature, and discharged from the discharge port (8). In the device
A vent (10) is provided between the supply port (4a) and the discharge port (8) of the cylinder (4), a drainage means (9) is provided in the cylinder (4) near the supply port (4a), and
Pushing means (A) having a pushing member (3, 3A) that pushes waste plastic (P) without plasticizing while adjusting the feed amount by driving by the driving means (2, 2A) is connected to the supply port (4a ), And the waste plastic (P) is increased in bulk density and supplied to the cylinder (4). The waste plastic processing device according to claim 1, wherein the pushing member (3) is a screw (3) for applying a propulsive force toward the supply port (4a). The waste plastic processing apparatus according to claim 1, wherein the pushing member (3A) is a piston (3A) pushed toward the supply port (4a).

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