JP2000051820A - Method for treating chlorine-containing plastic and production of solid fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating chlorine-containing plastic which can increase the dechlorinatioan velocity of the plastic even under low temperature conditions and a method for producing solid fuel of low chlorine content with the use of the treatment method. SOLUTION: In a method for treating chlorine-containing plastic in which a mixture of the chlorine-containing plastic and a heating medium is heated to dechlorinate the plastic and a method for producing solid fuel in which a mixture of chlorine-containing plastic and a heating medium is heated, and the plastic, after being dechlorinated. is cooled, the mixtures are incorporated with one or more kinds of compounds selected from amines, compounds which produce amines when decomposed, and heterocyclic compounds in which heteroatoms are nitrogen.

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 chlorine-containing plastics for dechlorinating chlorine-containing plastics, and a method for producing a solid fuel using the treatment method. The present invention relates to a method for processing chlorine-containing plastics and a method for producing a solid fuel using the processing method.

[0002]

2. Description of the Related Art Processing of chlorine-containing plastics such as polyvinyl chloride has been performed by landfilling or incineration. However, landfill processing has problems such as difficulty in securing land for landfill and contamination of groundwater.

[0003] In the case of incineration, hydrogen chloride is generated from chlorine-containing plastic, so that there are problems such as damage to the incinerator body and treatment of hydrogen chloride gas in exhaust gas. For this reason, it has become necessary to dechlorinate the chlorine-containing plastic beforehand and then treat it. Conventionally, as a method for dechlorinating polyvinyl chloride, a thermal decomposition method without using a medium has been mainly used.

[0004] The first problem of the above-mentioned thermal decomposition of polyvinyl chloride is that the polymer is carbonized in the course of the thermal decomposition, so that stirring cannot be performed sufficiently and the dechlorination rate is low.
It is considered that this is because carbonization of only the surface of the polyvinyl chloride proceeds, and chlorine is left inside. The second problem is that if the temperature at the time of thermal decomposition is lower than 250 ° C., the rate of the dechlorination reaction is extremely slow, and thermal decomposition under high temperature conditions is required.

[0005] In order to solve the first problem described above,
There has been disclosed a method of performing a dechlorination reaction by adding a heating medium to improve heat conduction and dispersion of polyvinyl chloride (JP-B-52-38594, JP-A-7-207279,
See JP-A-8-80685 and JP-A-9-40804). The above method uses a mineral oil, a petroleum-based organic solvent, a coal-based organic solvent or the like having a defined boiling point or the like as a heating medium, and can solve the first problem described above. Under the conditions, the described high dechlorination rate is not always obtained, and the above-mentioned second problem is not always solved.

A method for promoting dechlorination using concentrated sulfuric acid as a heating medium has been disclosed (Japanese Patent Publication No. 53-12 / 1983).
No. 552). However, the above-described method requires the addition of a highly corrosive chemical called concentrated sulfuric acid.
It is uneconomical due to the large amount of use. Further, a method using a mixed solvent of water and an organic solvent as a heating medium is disclosed (see JP-A-7-11026).

[0007] The method described above involves adding water,
Since the temperature is as high as 400 ° C., the reaction becomes extremely high pressure, and there is a problem that the reactor is complicated and the cost of the reactor increases.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides a method for treating chlorine-containing plastics, which can increase the dechlorination rate of chlorine-containing plastics even at low temperatures. An object of the present invention is to provide a method for producing a solid fuel having a low chlorine content using a treatment method.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that amines, compounds that decompose to form amines, and heterocyclic compounds in which the hetero atom is nitrogen are nitrogen. By including one or more selected from among the mixture of the chlorine-containing plastic and the heating medium, even at a temperature of 250 ° C or less,
The present inventors have found that the dechlorination reaction of chlorine-containing plastics proceeds sufficiently quickly, and reached the present invention.

That is, a first invention is a method for treating a chlorine-containing plastic, which comprises heating a mixture of a chlorine-containing plastic and a heating medium to dechlorinate the chlorine-containing plastic, wherein the mixture comprises an amine, This is a method for treating a chlorine-containing plastic, characterized by including one or more compounds selected from a compound which decomposes to form an amine and a heterocyclic compound in which a hetero atom is nitrogen.

A second invention is a method for producing a solid fuel, wherein a mixture of a chlorine-containing plastic and a heating medium is heated, and the chlorine-containing plastic is dechlorinated and then cooled to obtain a solid fuel. A method for producing a solid fuel, comprising one or more selected from an amine, a compound that decomposes to form an amine, and a heterocyclic compound in which a hetero atom is nitrogen.

In the first and second aspects of the present invention, in the mixture, one or more selected from the above-mentioned amine, a compound capable of decomposing to form an amine, and a heterocyclic compound in which a hetero atom is nitrogen. The total content of two or more is 0.
It is preferably from 01 to 50 parts by weight. In the first and second aspects of the present invention, it is preferable to use an organic solvent and / or a thermoplastic resin as the heating medium.

The cooling after the dechlorination in the second aspect of the present invention may be either cooling (natural cooling) or forced cooling. In the present invention, one or two or more selected from the above-described amine, a compound that decomposes to generate an amine, and a heterocyclic compound in which a hetero atom is nitrogen,
Also referred to as a nitrogen-containing compound.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail in the order of the chlorine-containing plastic, the heating medium, the nitrogen-containing compound, the treatment method, and the use of the dechlorinated product according to the present invention. [Chlorine-containing plastic:] The chlorine-containing plastic is not limited as long as it is a plastic in which a chlorine atom is bonded in a molecule, and polyvinyl chloride, polyvinylidene chloride, a copolymer of monomers forming these polymers,
Examples thereof include polychlorinated ethylene.

The chlorine-containing plastic may be a virgin plastic, or may be a plastic used in a greenhouse, a container / packaging material, a part of an electric product, an automobile part, etc., and then discarded. Further, in the present invention, a plastic containing no chlorine (hereinafter also referred to as a non-chlorine-containing plastic) may be contained in addition to the chlorine-containing plastic.

The shape of the chlorine-containing plastic may be a granular shape, a fibrous shape, a film shape, a sheet shape, or the like, and is not particularly limited. However, a fine shape is preferable so as to be easily mixed. [Heating medium:] As the heating medium in the present invention, liquids and solids having these functions can be used as long as they improve heat conduction and dispersion of chlorine-containing plastics. It is not something to be done.

Examples of the heating medium in the present invention include organic solvents, substances which melt during dechlorination, and powders such as iron powder. Of these, organic solvents such as petroleum-based organic solvents and coal-based organic solvents, and thermoplastic resins such as polyethylene and polypropylene melt at the temperature during dechlorination to dissipate heat and disperse chlorine-containing plastics. Those that make it good are preferred.

As the organic solvent, any of aliphatic compounds, alicyclic compounds, aromatic compounds and mixtures thereof can be used. Further, as the petroleum organic solvent, preferably A fuel oil, C fuel oil, light oil, kerosene and the like are exemplified, and as the coal organic solvent, preferably methyl naphthalene, indene, creosote oil, anthracene oil, coal tar, Examples thereof include naphthalene washing oil and crude naphtha oil.

The heating medium may be used alone, or two or more kinds may be used. The amount of the heating medium is 10 to 10 parts by weight based on 100 parts by weight of the chlorine-containing plastic.
Preferably it is 00 parts by weight. The mixing amount of the heating medium is more preferably 40 to 900 parts by weight based on 100 parts by weight of the chlorine-containing plastic.

If the amount of the heating medium is less than 10 parts by weight, the viscosity of the system becomes high, handling becomes difficult, and
Dechlorination hardly occurs. Conversely, the mixing amount of the heating medium is 1000
If the amount is more than parts by weight, the economic efficiency is reduced. When the organic solvent and the thermoplastic resin are used in combination as the heating medium, the preferable amount is 10 to 500 parts by weight of the organic solvent and 100 to 100 parts by weight of the chlorine-containing plastic.
800 parts by weight. [Nitrogen-containing compound] The feature of the present invention is that a nitrogen-containing compound is contained in a mixture of a chlorine-containing plastic and a heating medium.

The types of nitrogen-containing compounds are amines, compounds that decompose to form amines, and heterocyclic compounds in which the heteroatom is nitrogen. As the amine, any of primary amine, secondary amine and tertiary amine can be used, and ammonia may be used. Examples of the primary amine include methylamine, ethylamine, decylamine, dodecylamine, aniline, benzylamine, hexamethylenediamine and the like, and examples of the secondary amine include diethylamine, didecylamine, dibenzylamine, 2-benzylamine
Ethylhexylamine and the like, and as the tertiary amine, for example, trimethylamine, triethylamine,
Tribenzylamine and the like.

Examples of the compound capable of decomposing to produce an amine include phthalamic acid, acetanilide, dimethylformamide, acetamide, benzanilide, phthalimide, N-benzylphthalimide, and the like. Polyamide as a nitrogen-containing compound is added to a mixture. The amine formed by thermal decomposition can also be used. Examples of the heterocyclic compound in which the hetero atom is nitrogen include pyridine, picoline, lutidine, quinoline, isoquinoline, quinaldine, carbazole, ethyleneimine, pyrrolidine, piperidine, methylpiperidine, N-acetylpiperidine and the like.

The compounding amount of the nitrogen-containing compound is preferably 0.01 to 50 parts by weight, more preferably 0.05 to 20 parts by weight, based on 100 parts by weight of the chlorine-containing plastic. is there. If the compounding amount of the nitrogen-containing compound is less than 0.01 part by weight, the dechlorination rate is low,
If it exceeds 50 parts by weight, it is uneconomical.

As described above, the mixture according to the present invention may contain a plastic that is not chlorine-containing plastic (non-chlorine-containing plastic).
As the non-chlorine-containing plastic, any of virgin plastic and waste plastic and a mixture of both can be used. Therefore, waste plastics contained in municipal garbage and industrial waste, containers and packaging materials, and waste plastics generated in the process of dismantling electric appliances and automobiles may be used.

In the present invention, rather, as described above, polypropylene which can serve as a heating medium during dechlorination,
It is preferable that a chlorine-free thermoplastic resin such as polyethylene is present. Further, the mixture in the present invention may include glass, inorganic substances such as metals, papers, and the like. [Treatment method:] In the present invention, a mixture of a chlorine-containing plastic and a heating medium contains a nitrogen-containing compound, and the mixture is heated to dechlorinate the chlorine-containing plastic.

Dechlorination of chlorine-containing plastics is usually carried out by
In a form in which hydrogen chloride is desorbed, the dechlorinated chlorine-containing plastic becomes a black solid and is dispersed in the system. On the other hand, since the generated hydrogen chloride is usually in a gaseous state, the hydrogen chloride gas can be discharged out of the system and cooled and recovered by washing with water. The heating temperature for heating the mixture of the chlorine-containing plastic and the heating medium in the present invention is 150 to
The temperature is preferably 320 ° C, more preferably 200 to 250 ° C.

The above-mentioned heating temperature may be appropriately changed according to the amount of the chlorine-containing plastic, the viscosity of the mixture, and the like.
The higher the heating temperature, the more the dechlorination reaction proceeds, and it is preferable.

The heating time depends on the amount of the object to be dechlorinated, but is preferably 1 to 3 hours. At the time of heating, it is preferable to sufficiently stir the mixture so that the reaction proceeds efficiently. In the present invention, in order to sufficiently stir the mixture, a stirring blade for high viscosity may be used, or a kneader type strong stirring device may be used.

The pressure at the time of heating may be any of pressurization, normal pressure and reduced pressure, but the reaction proceeds sufficiently at normal pressure. [Use of dechlorinated product:] The dechlorinated product can be further heated and decomposed to be used as a liquid fuel, or it can be recovered as a solid and used as a solid fuel as described below. it can.

(1) When only an organic solvent is used as the heating medium (when there is no plastic other than the chlorine-containing plastic): In this case, the black solid formed by dechlorination of the chlorine-containing plastic is an organic solvent. A black solid can be separated by filtering the treated product or removing the organic solvent.

The removal of the organic solvent can be carried out by a usual method such as evaporation, drying, atmospheric distillation, and vacuum distillation. (2) When the mixture contains plastics other than chlorine-containing plastics: When the mixture contains thermoplastics such as polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyamide in addition to chlorine-containing plastics In the case of the above, the processed material having a high temperature after the completion of dechlorination tends to become a viscous liquid, and by cooling this, a black solid mass can be obtained.

As a cooling method at the time of solidification, it is possible to use cooling, charging in water, cooling using a refrigerant, and the like.
There is no particular limitation. The cooling rate is not particularly limited, but a higher cooling rate is particularly preferable when the obtained solid is pulverized and used for a solid fuel, a reducing agent for ore, or the like, because the obtained solid is easily pulverized.

That is, when a thermoplastic containing no chlorine is contained, for example, the treated product is heated from the heating temperature at the time of dechlorination to 100% within 10 minutes after the start of cooling.
It is preferable to cool to below ° C. In addition, a thermoplastic resin containing no chlorine is contained, and when an organic solvent is used as a heating medium, the organic solvent may be solidified with the organic solvent remaining, but the remaining amount of the organic solvent is preferably reduced.
Agglomeration becomes difficult.

Therefore, when the obtained solid is pulverized and used, it is preferable to remove the organic solvent. The preferred residual amount of the organic solvent is 30% by weight or less of the obtained solid. The removal of the organic solvent can be performed by a usual method such as evaporation, drying, atmospheric distillation, or vacuum distillation after dechlorination.

In the present invention, the above (1),
(2) In any case, it is preferable to remove inorganic substances such as glass and metal, papers, and the like from the processed material after dechlorination by hot filtration or the like. Further, in the present invention, it is more preferable to wash the obtained solid with water, an organic solvent, oil, or the like.

This is because the resulting solid is liable to adhere to the mist of the generated hydrogen chloride, and the above-mentioned washing can provide a treated material with even less chlorine content. Since the solid obtained by the treatment method of the present invention described above has a low chlorine content, iron ore exemplified as a fuel for combustion such as boilers, kilns and cupolas, and a reducing agent for a vertical furnace for producing pig iron such as a blast furnace. It can be used as a solid fuel such as an ore reducing agent such as stone.

This is because the solid obtained by the treatment method of the present invention has a low chlorine content. Therefore, when the solid is used as a fuel for combustion or an ore reducing agent, it contains chlorine or chlorine compound including when burning by-product gas. This is because it becomes possible to prevent chemical erosion of the refractory due to the above.

[0038]

EXAMPLES The present invention will be described below more specifically based on examples. (Example 1) 10 g of rigid polyvinyl chloride resin (chlorine content: 56.8 wt%) was placed in a 200-cc glass flask.
Dodecylbenzene: 50 g and quinoline (nitrogen-containing compound): 2 g were added, and the mixture was heated to 240 ° C. (heater heating) while being stirred using an squid type stirring blade.

After heating at 240 ° C. for 1.0 hour, the generated hydrogen chloride was discharged out of the system. Thereafter, the heating was stopped and the mixture was allowed to cool to room temperature. Since the obtained processed product was in a state where a black solid was dispersed in the solvent, the processed product was filtered to obtain a black solid as a filtration residue. After the black solid was washed with toluene and dried, the chlorine content in the black solid was measured. As a result, the chlorine content was 12.1 wt% (dechlorination rate: 78.7 wt%).

Table 1 shows the experimental conditions and experimental results of this example. The definition of the dechlorination rate is based on the following equation (1). Dechlorination rate = {[Chlorine content in chlorine-containing plastic (g)-Chlorine content in obtained solid (g)] / [Chlorine content in chlorine-containing plastic (g)]} x 100 (wt%) ... (1) (Examples 2, 3 and Comparative Example 1) Dechlorination was carried out in the same manner as in Example 1 except that the amount of quinoline was changed as shown in Table 1.

Table 1 shows the experimental conditions and experimental results of this example and the comparative example. (Examples 4 to 23, Comparative Examples 2 to 8) Chlorine was produced in the same manner as in Examples 1 to 3 and Comparative Example 1 except that the chlorine-containing plastic, the heating medium, and the nitrogen-containing compound shown in Table 2 were used. The plastic contained was dechlorinated.

In this example, the treated product obtained after the heat treatment of the mixture of the plastic and the nitrogen-containing compound was a viscous liquid, and the organic solvent in the treated solution was removed under the conditions shown in Table 2. Thereafter, it was cooled and solidified. Next, the obtained solid was washed with water and dried, and the chlorine content was measured. Table 2 shows the experimental conditions and experimental results of this example.

The chlorine content of the soft polyvinyl chloride used was 35.6 wt%, and Table 3 shows the breakdown of the mixed plastics A and B in Table 2. From the above results, the chlorine-containing plastic processed product obtained by the processing method of the present invention has a low chlorine content and is excellent for applications such as solid fuels used for boilers, kilns, cupolas, etc., and reducing agents for iron ore. It turns out that it is a thing.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

[Table 6]

[0050]

[Table 7]

[0051]

[Table 8]

[0052]

[Table 9]

[0053]

[Table 10]

[0054]

According to the present invention, the chlorine-containing plastic can be dechlorinated quickly at a lower temperature by adding a nitrogen-containing compound. In addition, since dechlorination can be performed at low temperatures, the amount of decomposition products is small, the generated hydrogen chloride can be recovered with high purity, and the generated solid can be used as a solid fuel. It is.

Furthermore, since high temperature and high pressure production conditions are not required, there is an advantage that a relatively simple reactor can be used.

Continued on the front page (72) Inventor Toshihide Suzuki 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba F-term in Kawasaki Steel Research Institute Co., Ltd. 4H029 CA16

Claims (2)

[Claims] 1. A method for treating chlorine-containing plastics, comprising heating a mixture of chlorine-containing plastics and a heating medium to dechlorinate the chlorine-containing plastics, wherein amines are decomposed into amines in the mixture. A method for treating chlorine-containing plastics, comprising one or more compounds selected from the group consisting of a compound and a heterocyclic compound in which the hetero atom is nitrogen. 2. A method for producing a solid fuel, wherein a mixture of a chlorine-containing plastic and a heating medium is heated, and the chlorine-containing plastic is dechlorinated and then cooled to obtain a solid fuel. A method for producing a solid fuel, comprising one or more compounds selected from a compound that decomposes to form an amine and a heterocyclic compound in which a hetero atom is nitrogen.