JP3942842B2 - Waste plastic processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waste plastic treatment apparatus, and more particularly, to a waste plastic containing a chlorine-based polymer for an apparatus for removing chlorine which causes generation of corrosive gas and toxic gas during combustion of waste plastic. It is related with the apparatus which supplies efficiently.
[0002]
[Prior art and problems]
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.
[0003]
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.
[0004]
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 Japanese Patent No. 2648412, Japanese Patent Laid-Open No. 9-310077 and 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.
[0005]
As a second method, there are methods described in JP-A-7-266339, JP-A-7-256644 and JP-A-7-112437. 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.
[0006]
Further, as a third method, there is a method described in JP-A-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. Japanese Patent Application Laid-Open No. 10-138246 also discloses that, as a conventional technique, plastic crushed by a pressure caused by the weight of the upper weight is pushed into a processing apparatus.
[0007]
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.
[0008]
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.
[0009]
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.
[0010]
In order to separate the compression function and the melting function of waste plastic as much as possible, the present invention not only provides a pressing member dedicated to compression, but also separates the melting function and the dechlorination function, and has an appropriate structure for each. Therefore, an object of the present invention is to provide a compact waste plastic processing apparatus having a large processing amount as a whole.
[0011]
[Means for Solving the Problems]
The present invention has been made in view of such a conventional technical problem, and the configuration thereof is as follows.
According to the first aspect of the present invention, waste plastic P containing a chlorine-based polymer is supplied from the supply port 4 a, plasticized and then heated to a predetermined temperature , and provided between the supply port 4 a and the discharge port 8. A preheating device B for discharging the steam from the vent 10 and discharging the waste plastic P from the discharge port 8;
Molten waste plastic discharged from the discharge port 8 of the preheating device B is supplied, the molten waste plastic is heated, the chlorinated polymer is pyrolyzed to generate a chlorine compound, and the molten waste plastic and the chlorine compound In a waste plastic processing apparatus having a dechlorination apparatus C separated into
At the bottom near the supply port 4a of the preheating device B, there is provided a drainage means 9 for preventing the waste plastic P from passing and discharging water ,
The pushing means A having pushing members 3 and 3A that push the waste plastic P having moisture without being plasticized while adjusting the feeding amount by driving by the driving means 2 and 2A is provided to the supply port 4a of the preheating device B. The waste plastic P is increased in bulk density and supplied to the preheating device B in accordance with the conveying capacity of the preheating device B, and a pressing force is applied to the waste plastic P near the supply port 4a. The waste plastic treatment apparatus is characterized in that it is drained from the drainage means 9 and supplied to the preheating device B.
The invention according to claim 2 is the waste plastic processing apparatus according to claim 1, wherein the pushing member 3 is a screw 3 that gives a propulsive force toward the supply port 4a of the preheating device B.
The invention according to claim 3 is the waste plastic processing apparatus according to claim 1, wherein the pushing member 3 </ b> A is a piston 3 </ b> A pushed toward the supply port 4 a of the preheating device B.
According to a fourth aspect of the present invention, there is provided the waste plastic processing apparatus according to the first, second or third aspect, wherein the waste plastic P pulverized to a predetermined size is supplied to the pushing means A.
A fifth aspect of the present invention is the waste plastic processing apparatus according to the first, second, third or fourth aspect, wherein the waste plastic P from which foreign matter has been removed is supplied to the pushing means A.
A sixth aspect of the present invention is the waste plastic processing apparatus according to the first, second, third, fourth or fifth aspect, wherein the waste plastic P washed with water is supplied to the pushing means A.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
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.
[0013]
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.
[0014]
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.
[0015]
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.
[0016]
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.
[0017]
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. Furthermore, 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.
[0018]
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 according to 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.
[0019]
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.
[0020]
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.
[0021]
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.
[0022]
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.
[0023]
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.
[0024]
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.
[0025]
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.
[0026]
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.
[0027]
【Example】
Example 1
After collecting the collected waste plastic P of general urban system as a pretreatment by removing materials other than plastics such as metal such as cans and bottles, glass, etc., a crusher manufactured by Horai Co., Ltd. (model: V03-480L (F ) 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.
[0028]
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.
[0029]
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 dechlorination equipment 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.
[0030]
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 those 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.
[0031]
【The invention's effect】
As can be understood from the above description, according to the waste plastic treatment apparatus of the present invention, the following effects can be obtained.
Since the waste plastic pushing means capable of increasing the bulk density can be provided at the supply port of the preheating device, the waste plastic can be supplied efficiently and stably. Also, the pushing means can adjust the amount of waste plastic that is fed, so that it can be fed at a higher density according to the bulk specific gravity of the waste plastic that has moisture as the raw material, and the amount of feed can be preheated. Can be matched to the transport capacity of
[0032]
In this way, the waste plastic compression function is given to the pushing means, and not only the waste plastic compression function by the preheating device is reduced to mainly bear the melting function, but also the melting function and the dechlorination function are combined with the preheating device. Since they are separated from the dechlorination apparatus, it is possible to provide an appropriate structure for each, and it is possible to provide a waste plastic processing apparatus that has a large processing amount and is compact as a whole. As a result, it can contribute to the reduction of the manufacturing cost of solid fuel.
[Brief description of the drawings]
FIG. 1 is a schematic view showing in cross section a waste plastic processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic view showing a cross section of a main part of a waste plastic processing apparatus according to a second embodiment.
[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 (6)

Waste plastic (P) containing a chlorine-based polymer is supplied from the supply port (4a), plasticized, heated to a predetermined temperature , and provided between the supply port (4a) and the discharge port (8) A preheating device (B) for discharging the steam from the vent (10) and discharging the waste plastic (P) from the discharge port (8);
Molten waste plastic discharged from the discharge port (8) of the preheating device (B) is supplied, the molten waste plastic is heated, the chlorinated polymer is pyrolyzed to generate chlorine compounds, and the molten waste plastic In a waste plastic processing apparatus having a dechlorination apparatus (C) that separates water and chlorine compounds,
At the bottom near the supply port (4a) of the preheating device (B) is provided drainage means (9) for preventing the passage of waste plastic (P) and discharging water ,
Pushing means (A) having pushing members (3, 3A) that push the waste plastic (P) having moisture while plasticizing it without adjusting the amount of feed while being driven by the driving means (2, 2A). Provided at the supply port (4a) of the heating device (B), the bulk density of the waste plastic (P) is increased , and the preheating device (B) is adapted to the conveying capacity of the preheating device (B). supplied, near the waste plastic (P) by applying a pressing force to the processing device of waste plastic characterized by Rukoto was drained from the drainage means (9) of the feed opening (4a).   The waste plastic processing device according to claim 1, wherein the pushing member (3) is a screw (3) that applies a propulsive force toward the supply port (4a) of the preheating device (B).   The waste plastic treatment device according to claim 1, wherein the pushing member (3A) is a piston (3A) pushed toward the supply port (4a) of the preheating device (B). The waste plastic treatment apparatus according to claim 1, 2 or 3 , wherein the waste plastic (P) pulverized to a predetermined size is supplied to the pushing means (A). The waste plastic processing apparatus according to claim 1, 2, 3, or 4 , wherein the waste plastic (P) from which foreign matter has been removed is supplied to the pushing means (A). Pushing the means (A), processor waste plastics according to claim 1, 2, 3, 4 or 5, characterized in that feeding the washed waste plastic (P) with water.

Images