JP2003160788A - Method for producing plastic decomposed oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a plastic decomposed oil whereby the plastic decomposed oil can be obtained even when temperature is lower than the conventional, and a reaction vessel used has a lower pressure resistance. <P>SOLUTION: The method for producing a plastic decomposed oil comprises allowing waste plastics, carbon dioxide, a hydrogen gas and a hydrogenation catalyst to reside in the same reaction vessel and decomposing the plastics under conditions of a temperature of at least 150°C and a pressure of at least 5 MPa. It is desirable that the carbon dioxide is used in an amount of at least 10 pts.wt. per 100 pts.wt. waste plastics. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing decomposed oil of plastic which can be used as a fuel by decomposing waste plastic, and more particularly to a method for producing decomposed oil of polyurethane resin such as polyurethane foam and polyurethane elastomer.

[0002]

2. Description of the Related Art As a technique for decomposing plastics into oil, a technique using supercritical water is known (Japanese Patent Application Laid-Open No. 2-212058).
001-81475). In this technique, waste plastic and water are mixed to form a slurry, and the waste plastic is used as a light oil under supercritical conditions of water.

Among the waste plastics, for polyurethane foam, a polyol raw material is prepared by heating a large amount of low-molecular weight glycol by utilizing the fact that the urethane bond is dissociated into an isocyanate group and a hydroxyl group at a temperature of about 210 ° C. The technique of reusing as is known (Japanese Patent Publication No. 53-34000) and has been put to practical use.

[0004]

However, in order to oilize waste plastics using supercritical water, there is a need for a method disclosed in Japanese Patent Laid-Open No. 2001-2001.
As described in Japanese Patent No. 81475, heating at a temperature of 374 ° C. or higher and pressurization at a pressure of 22 MPa or higher are required, and a large heat source and a reactor having high pressure resistance are required. In the above-mentioned Japanese Patent Laid-Open No. 2001-81475, the high temperature exhaust gas in the power generation facility is used as a heat source as a heat source, and the waste of using fuel for producing cracked oil is eliminated, but such a technique is Since it can be used only in a place having a heat source such as exhaust gas, it is poor in versatility. Moreover, the problem of requiring a reactor having high pressure resistance has not been solved yet.

In particular, rigid polyurethane foam widely used as a heat insulating material, soft polyurethane foam and polyurethane elastomer widely used as a mattress and a seat cushion pad of an automobile, have a high gas and high viscosity when simply heated to be oiled. , Which was a tar-like substance, and could only be obtained with no practical use.

Further, when a regenerated polyol is prepared by the technique disclosed in Japanese Patent Publication No. 53-34000, the regenerated polyol obtained has a high viscosity because it has a urethane bond in the molecule and is colored dark brown. Therefore, the rate of reuse is limited. Therefore, the technology of using cracked oil is required.

Moreover, since polyurethane foam has a low density and is bulky as compared with general plastics, the transportation cost per weight is high, and transportation to a place equipped with a power generation facility and a reactor having high pressure resistance is costly. There is a problem with
A recycling process that uses simple equipment near the place of consumption is required.

The present invention provides a method for producing cracked oil of plastic, which is capable of obtaining cracked plastic oil by using a reaction vessel having a lower temperature and lower pressure resistance than ever before.

[0009]

The method for producing a cracked oil of plastics according to the present invention is characterized in that waste plastic, carbon dioxide gas, hydrogen gas and hydrogenation catalyst are coexistent under the conditions of a temperature of 150 ° C. or higher and a pressure of 5 MPa or higher. It is characterized by decomposing plastic into plastic decomposed oil. With the manufacturing method having such a configuration, it becomes possible to obtain the decomposed plastic oil at a temperature lower than the conventional one and using a reaction container having a low pressure resistance. In particular, when it is used for producing a cracked oil of polyurethane, it is possible to obtain a cracked oil that is a practical low-viscosity light oil without becoming a tar- or pitch-like high-viscosity oil.

The equipment used in the above manufacturing method is
The pressure resistance is low, and the heating temperature is low, so a small heat source is sufficient. Therefore, since it is possible to select a wide range of places where it can be installed, the density is low and bulky, and therefore, in the production of cracked oil of polyurethane foam, which has a high transportation cost per weight, it is possible to perform a recycling process near the point of consumption, which is particularly preferable. .

Carbon dioxide is an inert gas which becomes a supercritical state at a low temperature of 31 ° C. and 7.3 MPa at a low pressure, and in particular, decomposed oil of waste plastic having a low viscosity at a low temperature and a low pressure can be obtained. In addition, the use of carbon dioxide gas is effective for generation of decomposed oil of polyurethane due to the action that the supercritical carbon dioxide gas swells the polyurethane particularly in the decomposition of polyurethane, thereby promoting the hydrogenation reaction. When the temperature is 150 ° C. or higher and the pressure is 5 MPa or higher, carbon dioxide is in a supercritical state or a so-called subcritical state.

The reason why the waste plastic can be oiled at a lower temperature and a lower pressure than in the conventional case has not been clarified exactly, but the use of hydrogen and a hydrogenation catalyst causes the molecule of the polymer constituting the plastic to be used. It is presumed that a large factor is that the organic radical having a small molecular weight, which is generated by thermal decomposition of the chain, is hydrogenated before the radical is recombined or crosslinked to increase the viscosity.

In the method for producing decomposed plastic oil of the present invention, the carbon dioxide gas is replaced with the waste plastic 100.
It is preferable to use 10 parts by weight or more, and more preferably 30 parts by weight or more with respect to parts by weight. If the amount of carbon dioxide used is too small, the reaction time required for the decomposition may be long. The carbon dioxide gas may be used in a large amount, but it is not preferable because a large reaction container is required for the oilification reaction.

In the above-mentioned method for producing cracked plastic oil, the hydrogen gas is preferably used at a gas concentration of 0.1% by volume or more, more preferably 3.0% by volume or more.

If the amount of hydrogen gas used is too small, the hydrogenation reaction does not sufficiently occur, and the viscosity of the obtained waste plastic cracked oil tends to increase. The hydrogen gas may be used in a large amount, but it is not preferable because a large reaction container is required for the oil conversion reaction.

The amount of the hydrogenation catalyst to be used is usually sufficient to be used in the hydrogenation reaction, and specifically, to the waste plastic to be treated as cracked oil, an amount of 0. It is 0.1 to 10% by weight, and more preferably 0.
It is 1 to 1.0% by weight. The catalyst can be separately recovered from the cracked oil and reused.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The plastic material which can be made into decomposed oil by the method for producing waste plastic decomposed oil of the present invention is not particularly limited, and general-purpose plastics can be treated.

The term "plastic" as used herein means not only a thermoplastic resin but also a so-called thermosetting resin.

Specific examples of the thermoplastic resin include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate, polystyrene resins, acrylic resins, polyamides such as nylon 6 and nylon 66. Examples include resins, ABS resins, polyoxymethylene, polycarbonate resins and the like.

Examples of the thermosetting resin include polyurethane resin, epoxy resin and phenol resin.

It is also applicable to an elastic body, and thermoplastic resins such as polyester elastomers, polyamide elastomers, polyolefin elastomers and polyurethane elastomers can also be oiled.

Waste plastics are
Grinding to an appropriate size is a preferred embodiment for shortening the reaction time. The size of the particles after crushing is preferably as small as possible from the viewpoint of decomposing oil, but is appropriately set in consideration of the number of crushing steps and the like. It is also a preferred embodiment that the waste plastic is dried and removed of water before being decomposed and oiled.

In the present invention, in addition to carbon dioxide and hydrogen, other inert gas may coexist. The inert gas is a substance that does not react with cracked oil or the like generated under cracking conditions and is a gas at normal temperature and pressure, and examples thereof include nitrogen and argon.

As the hydrogenation catalyst, known hydrogenation catalysts can be used without limitation. Specifically, nickel, cobalt, palladium, and other metals, and catalysts in which these metals and other metals are supported on a carrier, Pd or Fe supported on activated carbon, Ni-Mo / Al ₂ O ₃ , Co. -Mo / Al ₂
A catalyst such as O ₃ is exemplified.

The method for producing decomposed oil of waste plastics of the present invention may be carried out in a batch system or in a continuous system.

[0026]

EXAMPLES Example 1 Rigid polyurethane foam 10
0 g was crushed and then dried to remove water, Ni-M
2 g of o / Al ₂ O ₃ (a catalyst in which Ni and Mo are supported on alumina) was added, and the mixture was placed in a 300 cc capacity autoclave equipped with a stirrer, and the hydrogen partial pressure was 0.5 MP at room temperature.
a, carbon dioxide gas partial pressure was 7 MPa, hydrogen and carbon dioxide gas were filled so that the total pressure was 7.5 MPa, and heating was performed at 250 ° C. for 30 minutes.

The initial hydrogenation amount is 6.7% by volume,
The filling amount of carbon dioxide was 60 g, and the usage amount was 60 parts by weight based on 100 parts by weight of the rigid polyurethane foam.

When the contents were taken out after the reaction was completed,
A mixture of gas components, light oil of low viscosity, solid residue was obtained. The gas components were collected in a gas bag and analyzed by gas chromatography. In addition, the liquid components are GC-MS after weighing.
The composition of the solid residue is analyzed by C,
H and N were measured.

As a result of the analysis, gas components such as methane, CO,
Carbon dioxide was contained as the main component. 10 solid residues
%, And the light oil contained acetone, hexane, cyclohexane, methylcyclopentane, aniline, and naphthalene, and could be directly used as a fuel.

Continued front page    (72) Inventor Masaaki Kojima             1-17-18 Edobori, Nishi-ku, Osaka City, Osaka Prefecture             Toyo Tire & Rubber Co., Ltd. F-term (reference) 4F301 AB02 CA09 CA24 CA51 CA71                       CA72 CA73                 4H029 CA07 CA09

Claims (3)

[Claims] 1. Waste plastic, carbon dioxide gas, hydrogen gas,
And a hydrogenation catalyst coexist at a temperature of 150 ° C or higher and a pressure of 5
A method for producing a decomposed plastic oil, which decomposes the plastic under a pressure of MPa or more to give a decomposed plastic oil. 2. The waste plastic 1 containing the carbon dioxide gas
The method for producing a decomposed plastic oil according to claim 1, wherein 10 parts by weight or more is used with respect to 00 parts by weight. 3. The method for producing cracked plastic oil according to claim 1, wherein the hydrogen gas is used at a concentration of 0.1 vol% or more in the gas.