JPH11286572A - Oil-producing reactor unit and oil-producing plant for plastic waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil-producing plant which an accept an increasing amount of plastic wastes to be treated, allows easy design and fabrication, and allows operation substantially without changing the condition for the reaction. SOLUTION: This plant consists of (A) a reactor unit 10 consisting of a continuous reaction tube 1 and a body 10 which contains the continuous reaction tube, and (B) a heating means. A plurality of the reactor units can be placed in parallel depending on an amount of plastic wastes to be treated. Plastic wastes and water are mixed, and then distributed/supplied to each reactor unit. Optionally plastic wastes and water are separately distributed/supplied to each reactor unit. Each continuous reaction tube is heated by the heating means, so that plastic wastes are degraded under a reaction condition where water is in or near a super critical state, while the amount and condition for treating plastic wastes in each unit are kept equally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for decomposing and liquefying plastic waste using water in or near a supercritical region as a reaction medium, and more particularly to an oiling reactor having the same structure. TECHNICAL FIELD The present invention relates to a unit and a plurality of units provided in parallel for liquefying plastic waste.

[0002]

2. Description of the Related Art Conventionally, most of various plastic wastes have been subjected to landfill or incineration, and are not effectively used as resources. In addition, landfill disposal has problems such as difficulty in securing land for landfill and instability of the ground after landfilling, and incineration has caused problems such as furnace damage, generation of harmful gases and odors. Meanwhile, the Containers and Packaging Recycling Law was enacted in 1995, and the collection and reuse of plastics has become mandatory. In recent years, attempts have been made to recycle plastic waste in accordance with these circumstances, and one of them is to use water in the supercritical region (supercritical water) or water near the supercritical region as a reaction medium. A supercritical water reaction, a method of decomposing plastic waste into oil and recovering useful oils (supercritical water method) has been proposed (Japanese Patent Publication No. 56-501205, JP-A-57-4225, JP-A-5-31000,
JP-A-6-279762). Supercritical water means that the temperature is higher than the critical temperature (374 ° C.) and the pressure is the critical pressure (2
Water in a state of 2.1 MPa) or more. Since supercritical water easily diffuses into plastic oil droplets in a molten state, the supercritical water method has less residue than pyrolysis under normal pressure, It is believed that a high oil conversion can be achieved. Even if the temperature and pressure are below the critical temperature and the critical pressure, the behavior of water as a reaction medium exhibits almost the same characteristics as the behavior of supercritical water as long as it is near the critical temperature and the critical pressure. However, at present, technology for plastic waste treatment by the supercritical water method is not sufficiently established. When processing in a reactor, the inner diameter of the reactor tube becomes large, so that the wall thickness becomes too thick, making the production of the reactor tube difficult, or increasing the length of the reactor to increase the feed rate. The pressure of the fluid in the reactor increases and cannot be too long.
Further, when the tube diameter of the reactor is increased in accordance with the increase in the throughput, it is necessary to obtain various physical property values in designing.
Because of high temperature and high pressure conditions, their measurement and estimation are very difficult. On the operation side, there is a problem that it is difficult to control the heating of the reactor when the inner diameter of the tube of the reactor is increased or the length thereof is increased.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an oil for plastic waste which can cope with an increasing throughput of plastic waste, is easy to design and manufacture, and can be operated without significantly changing the reaction conditions. It is an object to provide a chemical conversion device.

[0004]

Means for Solving the Problems In order to achieve the above object, the present inventors studied the decomposition and oilification of plastic waste by supercritical water reaction, and found that the design, production, operating conditions, etc. Carefully consider and obtain a single reaction tube suitable for implementation, install substantially the same as this reaction tube in parallel, mix plastic waste and water in these reaction tubes It has been found that by supplying substantially uniformly, decomposition and oiling can be performed under the same conditions as in the case of the single reaction tube, and the present invention has been completed.

That is, a first aspect of the present invention comprises a tubular continuous reactor, a reactor heating means, and a housing for accommodating the reactor, and supplies a mixture of plastic waste and water to the reactor. The present invention relates to a plastic waste liquefaction reactor unit characterized by decomposing plastic waste under a reaction condition in which water is heated to a supercritical region or near a supercritical region by heating a vessel by a heating means. A second aspect of the present invention is that a plurality of tubular continuous reactors are housed in parallel in a housing, and each of the tubular continuous reactors is connected to a distribution pipe and a collection pipe, respectively, to distribute a mixture of plastic waste and water. To the reactor by
The first aspect of the present invention relates to a plastic waste liquefaction reactor unit which discharges a reaction product through a collection pipe. The third aspect of the present invention is the plastic waste oil conversion reactor unit according to the first or second aspect of the present invention, wherein the reactor heating means is a reactor heating medium supply means using a liquid or a gas. About. Fourth Embodiment of the Present Invention
The present invention relates to a plastic waste liquefaction apparatus in which a plurality of plastic waste liquefaction reactor units according to any one of the first to third aspects of the present invention are connected in parallel.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The type of plastic waste to be treated in the present invention is not particularly limited, and a thermoplastic plastic, a crosslinked plastic, a thermosetting plastic, or a mixture thereof can be used. Thermoplastics include not only general-purpose plastics but also engineering plastics. Specifically, polyethylene, polypropylene, poly-4-methylpentene-1, ionomer, polystyrene, AS resin, ABS resin, polyvinyl chloride,
Examples include polyvinylidene chloride, methacrylic resin, polyvinyl alcohol, EVA, polycarbonate, various nylons, various aromatic or aliphatic polyesters, thermoplastic polyurethane, cellulosic plastic, and thermoplastic elastomer. Examples of the cross-linked plastic include those obtained by cross-linking the above-mentioned thermoplastic with radiation, electron beam, light, etc., those cross-linked with a peroxide or the like, those cross-linked by adding a cross-linkable monomer, and the like. Thermosetting plastics include not only general-purpose plastics but also engineering plastics. Specifically, phenolic resins, urea resins, melamine resins, furan resins,
Examples include silicone resin, epoxy resin, unsaturated polyester resin, allyl resin, thermosetting polyurethane, rubber, and the like. These plastics may be of a single type, a mixture, or a composite material such as an alloy. The shape of the plastic waste is not particularly limited.

[0007] The plastic waste and water are mixed to form a tubular continuous reactor or a reactor in which a plurality of tubular continuous reactors are provided in parallel.
Both are supplied to the reactor), or the plastic waste and water are separately supplied to the reactor and mixed, and are decomposed and turned into oil under the reaction conditions in which the water is in the supercritical region or near the supercritical region. . Alternatively, the plastic waste may be mixed with water after being melted. For this reason, the plastic waste can be added to water by using an extruder or the like and pressurized after or together with the heating and melting. The water is preferably water having a temperature equal to or higher than the melting point of the plastic so that the molten plastic does not solidify. Water can also be pressurized and mixed with the plastic waste. That is,
By supplying both the plastic waste and the water under pressure to the mixing step, the plastic waste and the water can be directly supplied to the reactor. Alternatively, the plastic waste may be pulverized into powder, formed into a slurry with water, and then supplied to the reactor after pressurization. In this case, the size of the powder is preferably about 2 mm or less in diameter.

The water used in the reaction is not particularly limited in terms of type, temperature, pressure and the like, and can be used from water at normal temperature and normal pressure to water in the supercritical region or near the supercritical region. When water in the supercritical region or in the vicinity of the supercritical region is used, no heating means is required or a simple heating means capable of slightly heating can be used. The water separated from the reaction product can also be post-treated, if necessary, partly withdrawn to the outside and the remainder can be recycled to the mixing step as reaction medium. By recycling the water to the mixing process with plastic waste, the amount of newly supplied water and wastewater to be treated is reduced. The weight ratio of plastic to water is from 1: 0.3 to 20, preferably from 2 to 10, depending on the type of plastic from the viewpoint of oiling reactivity.

The plastic waste and water may be mixed in advance and then supplied to the reactor, or may be supplied to the reactor and mixed. In order to previously mix the plastic waste and water, a conventional mixing method can be used. For example, the mixing can be performed using a vertical or horizontal mixing tank with a stirring mechanism, a tube mixer, or the like. In the mixing process of plastic waste and water, the remaining high-boiling components obtained by distilling and separating distillates (gas, oil, and water) from the reaction product obtained by decomposing plastic waste should be added. Can be. Further, heavy oil can be supplied from outside and used in place of the high boiling component.

[0010] Plastic waste and water are mixed,
Feed to reactor. In the reactor, water becomes a reaction medium in or near the supercritical region, and the plastic waste is decomposed and turned into oil. The method for supplying the mixture is not particularly limited. The tubular continuous reactor preferably has an inner diameter of 3 to 50 mm,
It is a pipe with a length of 20 to 300 m, which may be straight,
It is housed densely in a housing in the shape of a letter, V, spiral, etc., for example, and parallel to each other for easy attachment and detachment. A preferred tubular continuous reactor is designed within the above numerical range, a tubular continuous reactor consisting of a single tube is manufactured, and a test is performed using the tubular continuous reactor to determine a basic reactor. A plurality of tubular continuous reactors are installed and operated in parallel.

The tubular continuous reactor housed in the housing is heated from outside the reaction tube by heating means. Examples of the heating means include an electric heater, a burner, a combustion gas, steam, and a heat medium. The means necessary to obtain the heated gas, heat medium, combustion gas, etc. may be inside or outside the housing. For example, when the combustion gas is used as the heating means, the burner for generating the combustion gas may be inside or outside the reactor unit, and the combustion gas used for heating the reactor may be the reactor unit. Supplied within. It is preferable to use a burner as a heating means and heat the reactor in the housing with the generated high-temperature combustion gas so that low-boiling component gas or oil, which is a plastic decomposition product, can be used as fuel.

The reaction apparatus may be a reactor unit in which one tubular continuous reactor is housed in one housing,
A plurality of tubular continuous reactors may be housed in one housing. In the case of a reactor unit, a plurality of them are provided in parallel according to the amount of plastic waste treated,
By distributing and supplying the high-temperature combustion gas to each reactor unit, each reactor can be heated under the same conditions.
In the present invention, even when one reactor unit and one heating unit are combined, including one reactor unit, a plurality of reactor units and one heating unit are combined. May be. A plurality of reactor units are provided in parallel according to the amount of plastic waste to be treated. In other words, when the amount of plastic waste treated increases by a factor of two, the reactor units are connected in parallel.
Provided. When the throughput increases 1.5 times, two reactor units are provided, and the entire throughput can be adjusted by the number of operating hours.

When a plurality of tubular continuous reactors are housed in a single housing, a burner can be provided in the housing to directly heat the reactor, or a high-temperature combustion gas can be supplied into the housing. Can also be heated. The number of tubular continuous reactors housed in one housing can be increased to a certain number according to the amount of plastic waste to be treated. In addition, a plurality of devices in which a plurality of tubular continuous reactors are housed in one housing can be used in parallel. In that case,
A high-temperature combustion gas can be supplied to the above-mentioned plurality of devices arranged in parallel to heat each reactor.

The shape of the reactor unit is such that a plurality of reactor units are provided in parallel, a plastic waste and water are mixed and supplied, and a high temperature combustion gas is supplied to the housing to heat the tubular continuous reactor. For this purpose, a flat plate structure as shown in FIG. 1 is preferable.

When a high-temperature combustion gas is used for the heating means, the supply port may be at the upper part, lower part, or side surface of the reactor unit, but preferably at the lower part or the lower part of the side surface so as to generate a flue effect. Yes, the outlet of the combustion gas is preferably provided at the top. The port for mixing and supplying the plastic waste and water may be provided in the case where the reactor unit or the plurality of tubular continuous reactors are housed in one housing, or in the upper, lower, or side surface of the housing. When using high temperature combustion gas, so that it is countercurrent to the flow of combustion gas,
Top or side top. However, it may be convenient to supply both cocurrently from below. The outlet through which the reaction product is discharged may be the case where the reactor unit or the plurality of tubular continuous reactors are housed in one housing, or the upper, lower, or side surface of the housing. Is preferably at the bottom if it is at the top, and at the top if the supply port is at the bottom. The supply port or the discharge port of the high-temperature combustion gas may be a simple cylinder, but may be a duct or a funnel.

FIG. 1 is a conceptual view showing an example of a reactor unit accommodating one tubular continuous reactor, and reference numeral 10 indicates the whole reactor unit. A tubular continuous reactor 1 folded in a U-shape is housed in a housing 2. The plastic waste and water are mixed and supplied from the supply port 5 to the tubular continuous reactor 1, and heated by the high-temperature heating gas supplied from the heating gas inlet 7 so that the water is in the supercritical region or in the vicinity of the supercritical region. And the plastic waste is decomposed and turned into oil. The reaction product is discharged from the outlet 6. The heating gas used for heating is discharged from the heating gas outlet 8.

As can be seen from FIG. 2, the plurality of reactor units can be arranged in parallel such that the front flat plates 3 or 3 'are parallel to each other. When the reactor units are arranged in contact with each other, the front flat plate 3 or 3 'with which one of the reactor units contacts is omitted by sharing the front flat plate 3 or 3' with which the reactor unit contacts. can do. Further, the reactor units are mutually connected to the side plate 4.
Alternatively, it is also possible to arrange 4 ′ in contact with each other. The supply of the raw materials to the reactor units may be performed by distributing and supplying the plastic waste and water to each reactor unit after mixing the plastic waste and water, or by separately distributing and supplying the plastic waste and water to each reactor unit. You may mix. Therefore, when the plastic waste and water are mixed and distributed and supplied to each reactor unit, there is a single distribution pipe 11 as shown in FIG. 2 for mixing the plastic waste and water. When distributing and supplying to each reactor unit individually, they are provided separately. In addition to being able to be arranged one-dimensionally, the reactor units can be installed laterally. FIG. 2 shows a two-dimensional arrangement. Of course, it is also possible to stack three-dimensionally by stacking in the height direction. The reactor unit can be expanded in this way,
It is advantageous in terms of construction materials, construction, heat radiation, and the like. The plurality of reactor units can be tightly connected to each other and fixed by fastening means such as bolts / nuts.

FIG. 3 is a conceptual diagram showing a case where a plurality of tubular continuous reactors are housed in one housing. A plurality of tubular continuous reactors 1, 1 ′ and the like folded in a U-shape are housed in a housing 2. Plastic waste and water are mixed and supply port 5
Is supplied to the tubular continuous reactors 1, 1 ′, etc. by the distribution pipe 11, and is heated by the high-temperature heating gas supplied from the heating gas inlet 7, and water is turned into a supercritical region or a reaction medium near the supercritical region. The plastic waste is decomposed and turned into oil. The reaction product is collected by the collection pipe 12 and discharged from the outlet 6. The heating gas used for heating is discharged from the heating gas outlet 8. The upper part of the housing may have a chimney shape to serve as an outlet for combustion gas.

A pipe for preheating water for mixing with plastic waste can be provided in the housing, and can be heated by high-temperature combustion gas.

From plastic waste and water, at high speed,
The reaction conditions for decomposing the oil so as to be a main component include a critical temperature of 374 since water becomes a medium in a supercritical region.
C. or more, critical pressure 22.1 MPa or more, or in order to become a medium near the supercritical region, the temperature must be 300 ° C. or more, and the pressure must be 0.8 times or more the critical pressure. The temperature range for decomposing the plastic waste in the presence of water in or near the supercritical range is 350 to 650 ° C, preferably 400 to 600 ° C. If the temperature is too high, a large amount of gas is generated. The reaction time for decomposing the plastic waste to produce an oil component is 30 minutes or less, preferably 10 minutes or less. If the reaction time is too long, it is not preferable because the throughput of the oiling device is reduced, a large amount of gas is generated, and carbon is generated. When a high-boiling component or heavy oil is added to the plastic waste, the added high-boiling component or heavy oil is decomposed together with the decomposition of the plastic waste, and a lower-boiling oil is obtained. Therefore, in order to obtain the oil component of the target boiling point range as a main component, the type of plastic waste, the type and circulation amount of high boiling components or heavy oil, the amount of addition, the ratio of water, the reaction temperature, the reaction pressure, Select the reaction time, etc.

The reaction product is introduced into a gas-liquid separator, a distillation column, or the like, as it is, or if necessary, cooled, or through a flash valve, to be separated into necessary components. The reaction products are a gas component, oil and moisture. The gas component is mainly a hydrocarbon having 4 or less carbon atoms, and can be used as it is or by removing hydrogen chloride or the like, and used as a fuel for heating the reactor, or used for other purposes. it can. The oil content includes low-boiling hydrocarbons having 5 or more carbon atoms to oils such as heavy oil and high-boiling components such as plastics being cracked. The oil is distilled and has low boiling components (distillate) such as naphtha equivalent, kerosene equivalent, light oil equivalent, etc.
It is separated into high boiling components (distillation residue) corresponding to heavy oil and residual oil. The oil is extracted to the outside and used as a fuel, a raw material, a material, etc., but a part can be used as a fuel for heating the reactor. When used as a fuel, the gas component and the low-boiling components separated by distillation have less sulfur and heavy metal components that cause pollution than heavy oil and coal, and have a high calorific value during combustion. In addition, oil is fractionated and various fuels,
It can also be used as a raw material for chemical synthesis, a hydrocarbon-based solvent, and the like. The high-boiling components can be circulated to the mixing step of the plastic waste and water. By circulating and adding high boiling components to the plastic waste, the high boiling components are decomposed and converted to lower boiling components.

In FIGS. 1 to 3, it goes without saying that the supply port 5 can be provided at the lower part of the housing and the discharge port 6 can be provided at the upper part.

FIG. 4 is a block flow diagram showing an example of a process for treating plastic waste. The injected plastic waste 21 is mixed with the pressurized water 22 and supplied to the reactor unit 10 where it is heated and the water becomes a reaction medium in or near the supercritical region, and the plastic waste is decomposed. Oil. The reaction product 23 is separated into a gas component 24, an oil component 25, a water content 26 and the like by the separator 16 via the flash valve 15. The water 26 can be used for mixing with the plastic waste 21.

[0024]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples, and the dimensions of the reactor, reaction conditions, and raw materials may be variously selected within the scope of the present invention. Can be.

(Examples 1 and 2) In Example 1, one reactor unit shown in FIG. 1 was used.
The two reactor units were used in parallel so that the front flat plates were in contact with each other. The tubular continuous reactor in the reactor unit has an inner diameter of 10 mm and a length of 40 m. The raw materials, reaction conditions and results are shown in Table 1.

[0026]

[Table 1]

In Example 2, the processing amount of the plastic waste was increased 10 times as compared with Example 1, but the composition of the product was almost the same as Example 1. As described above, by using a plurality of the same reactors, the equipment can be easily enhanced, and the plastic waste can be decomposed into oil under the same conditions.

[0028]

[Effect of the Invention] Even if the processing amount of plastic waste increases, it can be processed under the same conditions, decompose at a high speed under a supercritical or near supercritical condition of water, and in a large amount, It can be turned into oil. Further, since the same reactor can be used, there is no need to measure or estimate data according to the throughput, and design and production are easy. Further, since the size and the like of the reactor are standardized, the reactor can be easily added and a compact reactor can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a reactor unit.

FIG. 2 is a diagram showing an example in which a plurality of reactor units are two-dimensionally arranged in parallel to form one reactor.

FIG. 3 is a diagram showing an example in which a plurality of reaction tubes are arranged in parallel and housed in one housing.

FIG. 4 is a system flow diagram showing decomposition and oilification of plastic waste.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tubular continuous reactor 1 ′ tubular continuous reactor 2 housing 3 front flat plate 3 ′ front flat plate 4 side plate 4 ′ side plate 5 supply port 6 discharge port 7 heating gas inlet 8 heating gas outlet 10 reactor unit 11 minute piping 12 Collection tube 15 Flash valve 16 Separator 21 Plastic waste 22 Water 23 Reaction product 24 Gas 25 Oil 26 Moisture

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Wataru Matsubara 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Kazuto Kobayashi Kannon-Shimmachi 4 in Nishi-ku, Hiroshima-shi, Hiroshima 6-22, Citizen, Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Satoru Sugita 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Heavy Industries, Ltd.

Claims (4)

[Claims] The present invention comprises a tubular continuous reactor, a reactor heating means, and a housing for accommodating the reactor. A mixture of plastic waste and water is supplied to the reactor, and the reactor is heated by the heating means. Wherein the plastic waste is decomposed under a reaction condition in which water is in a supercritical region or near a supercritical region. 2. A plurality of tubular continuous reactors are housed in parallel in a housing, each tubular continuous reactor is connected to a distribution pipe and a collection pipe, respectively, and a mixture of plastic waste and water is reacted by a distribution pipe. 2. The plastic waste oil conversion reactor unit according to claim 1, wherein the reaction product is supplied to a reactor and the reaction product is discharged through a collection pipe. 3. The plastic waste oil conversion reactor unit according to claim 1, wherein the reactor heating means is a reactor heating medium supply means using a liquid or a gas. 4. An apparatus for liquefying plastic waste, wherein a plurality of the liquefaction reactor units for plastic waste according to claim 1 are connected in parallel.