JPH10265610A - Process for treating waste plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To collect and transport waste plastics at good efficiency by volume reduction by collecting waste plastics from general wastes, mixing them with a solvent in a specified ratio, kneading and dissolving the mixture to effect volume reduction and transporting the waste plastics reduced in volume. SOLUTION: The waste plastics are desirably foamed plastics. The solvent used is desirably kerosene, light oil, heavy oil, a waste lubricating oil or regenerated oil. 100 pts.wt. solvent is used per 10-150 pts.wt. waste plastics. Desirably the upper limit of the kneading/dissolution temperature is 250 deg.C, and the lower limit is 150 deg.C. Although the time of kneading/dissolution varies with the heating temperature or the mixing ratio of the waste plastics to the solvent, it is desirably 5-120 min. A ground waste plastic having a piece size distribution in which pieces 1-5 cm in size constitute at least 90 wt.% of the entire pieces and/or an unground waste plastic are desirable. An example of the method for kneading/dissolution consists of agitation with an agitator provided with 1 or 2 impellers capable of powerful kneading and agitation and different in shape at a revolution speed of 100-1,500 rpm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating waste plastic, and more particularly, to a method for improving the efficiency of a waste plastic collection and transportation system.

[0002]

2. Description of the Related Art At present, a general waste collection / transportation system separates and discharges waste from a general house into combustible and non-combustible materials, and collects the waste using a dump truck or a compression collection truck. And, they are transported to the waste incineration plant by the station collection method. Combustible materials include, for example, garbage, garbage, paper waste, waste plastic, and the like, and
Non-combustible materials include, for example, glass bottles, iron or aluminum cans, large waste wood, iron shavings, and the like. At present, waste plastics contained in combustible materials have various problems such as damaging the inner walls of incinerators and discharging chlorine-based gas when burning in refuse incinerators due to their high calorific value. is there. Therefore, the collected waste plastics have been separately treated as incompatible incineration wastes, and it has been studied to separate and collect them as so-called raw materials for material recycling or thermal recycling.

Further, in the current general waste collection / transportation system, there is a shortage of storage space due to an increase in the amount of garbage collected, and remote disposal / disposal facilities have been inevitable in terms of environmental circumstances. There are problems such as remoteization of such facilities and a decrease in transportation efficiency due to deterioration of traffic conditions.
For this reason, it is necessary to consider a waste collection method according to the capacity of the facility, for example, to consider an efficient collection and transportation system in the future, including the transportation method and the necessity and role of the relay facility. .

[0004] In recent years, the number of cases where waste plastics are separated and collected, or separated after collection and disposed of in landfills has been increasing. In order to increase landfill efficiency, landfill disposal is performed after reducing the volume of waste plastic. As a method for reducing the volume before landfill, a melt-solidification method is currently mainly used, and examples thereof include a screw extrusion method, a compression / fusion method (hot bind), and a fusion / compression method. There is a drawback that the use of such equipment and devices is required. Although these methods are effective as pre-treatment for landfill, they are not effective methods for improving transportation efficiency because the location of facilities is restricted.

[0005] Other methods for reducing the volume of waste plastics include pulverization and compression filling. The pulverization treatment is a method of coarsely pulverizing and / or finely pulverizing waste plastic, and any method is simple, but a large volume reduction effect cannot be expected. As the compression filling process, for example, a method using a compression type collection vehicle used during normal collection work can be cited, but the effect of volume reduction is still small.

[0006] Therefore, because of the high bulk density, the efficiency of collection and transportation is low, and a large storage space is required. Furthermore, how to efficiently reduce the volume of waste plastic that is inefficient in landfill is a problem. It has become a major issue in considering plastic collection and transport systems.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a simple waste plastic capable of efficiently collecting and transporting waste plastic discharged as general waste by significantly reducing the volume of bulky waste plastic having a high bulk density. It provides a processing method.

[0008]

Means for Solving the Problems The present inventors have conducted various studies to solve the above problems. As a result, it has been found that the use of the following predetermined method can easily and significantly reduce the volume of waste plastic and can solve the above-mentioned problems, and have completed the present invention.

That is, the present invention provides (1) (I) a step of collecting waste plastic in general waste, and (II) mixing the waste plastic with a solvent, and then kneading and dissolving (kneading / dissolving). And (III) a step of transporting the reduced-volume waste plastic.

The volume reduction step (II) in the method of the present invention is simple and its location is not restricted. Therefore, it is possible to set up a relay base in a collection area or an area adjacent to the collection area in the system for collecting and transporting waste plastic, and reduce the volume there. It is also possible to reduce the volume on the collection vehicle while collecting. Therefore, the subsequent transportation efficiency can be significantly improved. Further, since the reduced volume of waste plastic is a solid (for example, rubber, rice cake or chocolate) at room temperature, it can be temporarily stored in a warehouse or the like like a normal solid substance. Therefore,
These can be used as a material for material recycling or thermal recycling at any time. Or,
Landfilling of the reduced volume in a conventional waste plastic landfill may also be adopted. In this case, since the volume is reduced, it is possible to extend the life of the landfill disposal site.

In a preferred embodiment, (2) the method according to the above (1), wherein the step (II) is carried out on a waste plastic collection vehicle, and (3) the step (II) comprises the steps of:
0 parts by weight are mixed with 100 parts by weight of a solvent, and then the mixture is kneaded and dissolved at room temperature to 250 ° C. for 5 minutes or more, and the method according to the above (1) or (2) is carried out. The above (3), wherein the dissolution time is 5 to 120 minutes.
(5) The method according to any one of the above (1) to (4), wherein the waste plastic to be reduced in volume is a foamed plastic, (6) the waste plastic to be reduced in volume is: The method according to any one of the above (1) to (5), which is a plastic container or tray discharged from a general house, (7) Distribution of the maximum size of each piece of waste plastic whose volume is to be reduced The method according to any one of the above (1) to (6), which is a pulverized product and / or an unpulverized product containing 90% by weight or more of a piece having a size of 1 cm or more in
(8) The waste plastic whose volume is reduced is composed of 90% by weight of a piece having a size of 1 to 5 cm in a distribution of a maximum size of each piece.
The method according to any one of the above (1) to (6), which is a pulverized product and / or an unpulverized product including the above, can be mentioned.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In step (II) of the present invention, the mixing ratio of waste plastic and solvent is preferably 10 to 150 parts by weight of waste plastic and 100 parts by weight of solvent, particularly preferably 65 to 65 parts by weight of waste plastic. The solvent is 100 parts by weight with respect to 100 parts by weight. If the amount of the waste plastic is less than the above lower limit, the treatment efficiency is poor, and if it exceeds the above upper limit, kneading / dissolution is not sufficiently achieved. Any volume-reduced material kneaded / dissolved using a mixing ratio of the waste plastic and the solvent within the above range is in a solid state (for example, a rubber state) and can be used for landfill as it is.

The upper limit of the kneading / dissolving temperature is preferably 2
The temperature is 50 ° C, particularly preferably 200 ° C, and the lower limit is affected by the type of the solvent and the waste plastic, but is preferably room temperature, particularly preferably 150 ° C, more preferably 170 ° C.
It is. If it is less than the above lower limit, it is difficult to knead / dissolve the waste plastic, and if it is more than the above upper limit, thermal decomposition of the waste plastic becomes severe, and it is environmentally unfavorable due to bad smell due to generation of toxic gas such as chlorine gas.

The kneading / dissolving time varies depending on the heating temperature or the mixing ratio of the waste plastic and the solvent, but the upper limit is preferably 120 minutes, particularly preferably 60 minutes, and the lower limit is preferably 5 minutes, particularly preferably. 30 minutes. Below the lower limit, kneading / dissolving is not sufficient,
Even if the upper limit is exceeded, no further effect can be expected because kneading / dissolution has been sufficiently achieved by then.

The waste plastic used in the step (II) preferably contains 90% by weight or more of a piece having a size of 1 cm or more, particularly preferably a piece having a size of 1 to 5 cm in the maximum size distribution of each piece. And / or unground material. If the size is less than the above lower limit, the cost for grinding the waste plastic increases, which is not appropriate. Therefore, there is an advantage that the waste plastic collected in the step (I) can be subjected to volume reduction treatment without being pulverized or with a degree of coarse pulverization.

The waste plastic used for volume reduction is preferably a foamed plastic (plastic foam). For example, polystyrene foam, AS foam, ABS foam, polyethylene foam, polypropylene foam, polyvinyl chloride foam, polyvinyl alcohol foam, polyamide foam, etc. as thermoplastic foam, and polyurethane foam, phenolic resin foam, urea as thermosetting foam Resin foam, epoxy resin foam, acrylic resin foam, silicone foam, pyranyl resin foam, polyisocyanurate foam, polyimide foam and the like. Of course, plastics other than foamed plastics can also be used. The volume reduction processing in the present invention is particularly effective for, for example, plastic containers or trays discharged from ordinary houses.

Solvents used for volume reduction include heavy oil A,
Petroleum heavy oils such as B heavy oil and C heavy oil, kerosene, light oil and their waste oils, or spindle oil, refrigeration oil, dynamo oil, turbine oil, machine oil, internal combustion engine oil, cylinder oil, marine engine oil, gear oil , Cutting oils, automatic transmission oils, compressor oils, rolling oils, electrical insulating oils, hydraulic oils, petroleum-based lubricating oils such as rust-preventive oils, and waste oils thereof, or olefin oils, alkylbenzenes, polyalkylene glycols, fatty acid esters , Phosphate esters, silicate esters, polychlorotrifluoroethylenes, aromatic halides and other synthetic lubricating oils and their waste oils, or waste vegetable oils, or organic compounds such as benzene, xylene, toluene, styrene, tetrahydrofuran Solvents and the like, or decomposed oil or autogenous oil generated by decomposition of plastics may be used. These solvents can be used alone or as a mixture. When mixed and used, there is no particular limitation on the mixing ratio or the type of solvent to be mixed. There is no particular limitation on the solvent when used for material recycling or thermal recycling. When used for landfills, petroleum-based heavy oil, petroleum-based lubricating oil, synthetic lubricating oil or waste oil thereof is preferred. In any of the above cases, kerosene, light oil, heavy oil, waste lubricating oil or natural oil is particularly preferably used.

The method of kneading / dissolving used in step (II) of the present invention is not particularly limited. For example, a heating and mixing tank provided with a stirrer in which one or two or more stirring blades of different shapes capable of strong kneading and stirring can be used, and the kneading is preferably performed by stirring at a rotation speed of 100 to 1500 rpm. / Dissolve. The temperature of the kneading / dissolving is influenced by the type of the solvent and the waste plastic as described above.
For example, using polystyrene as waste plastic,
When styrene is used as the solvent, kneading at room temperature /
Dissolution is possible. On the other hand, when mixed plastics such as polyethylene and polypropylene are used as waste plastics and heavy oil A is used as a solvent, the mixture is preferably kneaded / dissolved by heating to 200 ° C. The heating method is not particularly limited, and a method using a heat medium is preferably used. Also, electric heating may be used. The procedure for kneading / dissolving is not particularly limited, either. For example, a method in which a solvent is charged into a heating and mixing tank at room temperature, heated to a predetermined temperature, and then waste plastic is charged and kneaded / dissolved. A method of mixing a part of the waste plastic into a heating and mixing tank, heating the mixture to a predetermined temperature, and then charging and kneading / dissolving the remaining waste plastic, for example, previously heating the heating and mixing tank to a predetermined temperature with a heat medium, A method in which a pre-heated solvent is added thereto, and then the waste plastic is charged and kneaded / dissolved, or the solvent and the waste plastic are mixed by the above-described methods, and then the viscosity of the mixed solution is increased. A method in which a mixture of a solvent and waste plastic is charged and kneaded / dissolved, or the like, may be used.

Next, an embodiment of the method of the present invention for reducing the volume in the relay station apparatus will be described with reference to FIG. Waste plastic 1 collected as general waste is 0.1 to 2
It is usually introduced by a conveyor (not shown) into a coarse crusher 2 having a processing capacity of tons / hour, and each piece is crushed into a coarse crushed product having a maximum size of about 5 cm. Next, in the kneading / dissolving tank 4, a solvent previously heated to about 200 ° C. by a heat medium or an electric heater in the solvent tank 3 (for example,
A heavy oil or waste lubricating oil) to prepare a mixture having a waste plastic to solvent weight ratio of approximately 1: 1.
Thereafter, the volume is reduced by kneading / dissolving at about 170 to 200 ° C. for about 30 minutes using a strong kneading stirrer. The volume-reduced waste plastic is then cooled in the cooling tank 5. The kneading / dissolving is usually performed in a batch system, and the processing amount in one batch is about 200 to
1000 kg. The waste plastic thus reduced in volume is once collected at a transfer station and transported, and used as a material for material recycling or thermal recycling, or as a landfill.

According to the present invention, waste plastic discharged separately from a general house is not directly transported to a landfill or the like, but a relay station is provided on a collection vehicle or in a separated collection area or an area adjacent thereto. And volume reduction processing can be performed there. Therefore, collection efficiency in the separate collection area is improved. For example, if the volume reduction processing is performed on a collection vehicle, it is possible to reduce the number of collection vehicle tours and to reduce the number of collection vehicles and the number of workers. If the volume is reduced at the transfer station, the transportation efficiency from the transfer station to the landfill site can be significantly improved. For example, if the volume can be reduced to 1/10, the number of garbage collectors can be reduced to about 1/8 to 1/10, and the number of vehicles from the relay base to the landfill site can be reduced to 1/10. It can be reduced to a degree.

Further, the reduced waste plastic can be directly transported from a relay station to a recycling factory as a material for material recycling or thermal recycling. As material recycling, for example, use as a plastic synthesis raw material, a raw material for reshaping plastic products, a raw material for polymer alloying, etc. is considered, and as thermal recycling, for example, a fuel for power generation, a fuel for hot water production, an industrial boiler It can be used as fuel, dry distillation fuel, gasification fuel, liquefaction fuel, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0023]

【Example】

[0024]

Example 1 A foamed polystyrene tray used for packing fish was crushed so that each piece after crushing had a maximum diameter of 5 to 10 c.
m was coarsely pulverized. Next, 10 grams of the coarsely pulverized material was weighed and placed in a 2 liter stainless steel ball. At this time, the apparent volume of the expanded polystyrene after the coarse pulverization was 1 liter (bulk density: 0.01 g / c).
c).

Next, 5 g of light oil and 5 g of styrene oil were added to the above-mentioned ball containing the coarsely pulverized expanded polystyrene, and the mixture was manually kneaded with a spatula for about 30 minutes at room temperature to dissolve. The apparent volume of the product was about 20 cc (bulk density: about 1 gram / cc).

As described above, the volume was remarkably reduced to 1/50 even though an equal weight of oil was added to the coarsely ground foamed polystyrene and kneaded.

[0027]

Comparative Example 1 10 g of the coarsely pulverized expanded polystyrene used in Example 1 was finely pulverized for 5 minutes by a small stirring and pulverizer having an internal volume of 2 liters. Finely pulverized material (1 to 10 mm
The apparent volume was about 500 cc (bulk density: about 0.02 g / cc). Volume reduction was 1/2.

[0028]

Example 2 10 g of the coarsely pulverized expanded polystyrene used in Example 1, 7 g of polyethylene powder (particle size of 1 mm or less), 7 g of polypropylene pellet (particle size of 1 mm or less), and polyvinyl chloride powder (particle size of about 1 m)
m) 6 grams were weighed and placed in a 2 liter stainless steel bowl. At that time, the apparent volume of the mixture was 1 liter (bulk density: 0.01 g / cc).

Next, 20 g of light oil and 10 g of styrene oil were added to the ball containing the above mixture, and the mixture was manually kneaded with a spatula at room temperature for about 30 minutes to dissolve. The apparent volume of the product was about 60 cc (bulk density: about 1 gram / cc).

Thus, its volume was significantly reduced to 3/50.

[0031]

Example 3 As a kneading / dissolving tank, a heated mixing tank having an internal volume of 20 liters equipped with a strong stirrer equipped with two stirring blades was used. First, 5 liters of waste engine lubricating oil was put into the mixing tank and heated to about 180 ° C. Then
500 g (about 50 liters) of a foamed polystyrene tray used for packing fish was previously crushed so that the maximum diameter of each piece after crushing was 5 to 10 cm,
The mixture was gradually charged into the heating and mixing tank, and kneaded / dissolved by stirring at a rotation speed of 150 rpm.

The expanded polystyrene was melted and dissolved in the solvent at the same time as the injection, and was apparently completely kneaded / dissolved after 5 to 10 minutes. Thereafter, without cooling, the product was discharged out of the mixing tank and then cooled. The apparent volume of the product was about 5.5 liters. The volume of the product is about 1 /
The volume was reduced to 10.

[0033]

Example 4 In the same heating and mixing tank used in Example 3,
5 liters of waste engine lubricating oil was charged and heated to about 180 ° C. Then, a polyethylene wide tape piece cut to a length of about 10 cm and a polyethylene lunch container piece crushed in advance to have a length of 5 to 10 cm are alternately charged, and a total of 1500 g (about 15 liters) and 500 g, respectively, are added.
Grams (about 30 liters). Rotation speed 1
The kneading / dissolution was carried out by stirring at 50 rpm.

The above polyethylene product was melted and dissolved in the solvent at the same time as the introduction, and after 30 minutes, it was apparently kneaded / dissolved completely. The temperature at this time was 200 ° C.
Thereafter, without cooling, the product was discharged out of the mixing tank and then cooled. The apparent volume of the product was about 6 liters. The volume of the product was reduced to about 1/8 the volume of the crushed material of the raw polyethylene product.

From the above Examples and Comparative Examples, it was found that when the method of the present invention was used, remarkable volume reduction of waste plastics could be achieved, and efficient collection and transportation of waste plastics was possible. . On the other hand, it was found that the conventional method based on fine pulverization was not effective because the degree of volume reduction was low.

[0036]

Industrial Applicability According to the present invention, waste plastics having high bulk density and bulk can be significantly reduced, and waste plastic discharged as general waste can be efficiently collected and transported.
A simple method for treating waste plastic is provided.

[Brief description of the drawings]

FIG. 1 is a flow chart showing an embodiment of the step (II) of the present invention in a case where volume reduction is performed by a relay base device.

[Explanation of symbols]

 1: waste plastic 2: coarse crusher 3: solvent tank 4: kneading / dissolving tank 5: cooling tank

Claims (5)

[Claims] (1) a step of collecting waste plastic in general waste, (II) mixing the waste plastic with a solvent,
Next, a step of reducing the volume by kneading and dissolving, and
(III) A method for treating waste plastics, comprising a step of transporting the reduced waste plastics. 2. The method of claim 1 wherein step (II) is performed on a waste plastic collection vehicle. 3. The method according to claim 1, wherein the step (II) comprises the steps of:
3. The method according to claim 1, wherein 50 parts by weight are mixed with 100 parts by weight of a solvent, and then the mixture is kneaded and dissolved at room temperature to 250 [deg.] C. for 5 minutes or more. 4. The method according to claim 1, wherein the waste plastic to be reduced in volume is a foamed plastic. 5. The waste plastic to be reduced in volume has a size of 1 to 5 cm in the size distribution of each piece.
The method according to any one of claims 1 to 4, which is a pulverized substance and / or an unpulverized substance containing 0% by weight or more.