JPH07286063A - Production of oily matter by thermal decomposition of synthetic polymer - Google Patents

Abstract

PURPOSE:To obtain an oily matter with a low halogen content efficiently while reducing the amts. of organohalogen compds. as the by-product by liquefying a mixture of a halogen-contg. synthetic polymer with a halogen-free synthetic polymer under specified conditions. CONSTITUTION:A mixture of a halogen-contg. synthetic polymer (e.g. PVC or PVDC) with a halogen-free synthetic polymer (e.g. a polyolefin or PS) is made flowable by melting or thermally dissolving in a solvent (e.g. sulfolane) and heated. In heating after or during the melting or thermal dissolving, the mixture is brought into contact with an inert gas, pref. a gas mainly comprising N2 or CO2 and/or a gas mainly comprising water vapor, to substantially remove separated halogenated substances. The melt or the soln. is then liquefied by thermal decomposition.

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 a petroleum oil by pyrolyzing a synthetic polymer. More specifically, the present invention is industrially used as a measure for treating and reusing plastic waste that has begun to be emphasized in environmental issues, by thermally decomposing it and producing useful oils such as fuel oil or raw oil. Regarding possible methods.

[0002]

2. Description of the Related Art It is conventionally known that when a synthetic polymer is heated to about 400 ° C. in the absence of oxygen, it is thermally decomposed to produce an oily substance, tar-like substance or pitch-like substance.

However, according to the conventional technique, when a halogen compound, especially a chlorine compound, is contained in the synthetic polymer which is a raw material for thermal decomposition, the halogen compound becomes a synthetic polymer during thermal decomposition. The reaction produces an organic halide, which is mixed in the cracked oil, resulting in a halide-containing oil. It is rumored that the use of halide-mixed oil as a fuel not only corrodes the boiler but also produces harmful substances such as dioxins. Therefore, the halide-mixed oil was difficult to use as a fuel.

Particularly, when a synthetic polymer which is a raw material for thermal decomposition contains a chlorine-containing polymer such as polyvinyl chloride, polyvinylidene chloride or chlorinated polyethylene, the thermal decomposition product is chlorinated. Many things are mixed.

[0005]

The object of the present invention is to produce oils having a chlorine content as low as possible by suppressing the generation of organic halides, particularly organic chlorides, especially during oiling by thermal decomposition. To provide a method.

[0006]

Means for Solving the Problems The inventors of the present invention, prior to oiling of a synthetic polymer by thermal decomposition, melt the synthetic polymer, which is a raw material for thermal decomposition, or dissolve it in a solvent to impart fluidity or flow it. In parallel with imparting the property, by blowing an inert gas into the polymer while keeping the fluid of the polymer at a predetermined temperature, it is possible to efficiently remove the halide, particularly the chloride produced. It was found that the chlorine content in the obtained decomposed oily substance can be significantly reduced. The method for producing an oily substance of the present invention has been completed as a result of further studies based on this finding.

<Pyrolysis raw material of the method of the present invention> The halogen-free synthetic polymer, which is one of the raw materials to be treated by the pyrolysis of the method of the present invention, contains both a thermoplastic resin and a thermosetting resin, Polyethylene which is a plastic resin (P
E), polyolefin (PO) such as polypropylene (PP), polystyrene (PS), high impact polystyrene (HIPS), ABS resin, ethylene-vinyl acetate copolymer resin (EVA) and polycarbonate (PC), and thermosetting Resins such as phenol resin, melamine resin, urea resin, alkyd resin and polyurethane (P
Any of U) and the like may be used alone or as a mixture of two or more kinds.

The halogen-free synthetic polymer, which is one of the raw materials for thermal decomposition of the method of the present invention, is not limited to a synthetic resin in a strict sense, but a soft polymer, a copolymer and a composition of two or more kinds thereof. A polymer that includes a wide range of substances,
Typical examples thereof are as follows: -ethylene wax-like polymer or grease-like polymer, -propylene wax-like polymer or grease-like polymer such as atactic polypropylene or-synthetic rubber such as ethylene-propylene copolymer rubber ( E
PM), ethylene-propylene-non-conjugated diene copolymer rubber (EPDM), styrene-butadiene copolymer rubber (S
BR), butadiene-acrylonitrile copolymer rubber (NBR), polyisoprene rubber (IR), butyl rubber (IIR), polybutadiene rubber (BR) and their crosslinked products (vulcanized products), thermoplastic elastomers such as ethylene-propylene- It also includes partially crosslinked products of non-conjugated diene copolymer rubber / polyethylene composition, styrene-butadiene copolymer hydrides and synthetic "hydrocarbon resins" such as commonly known as "petroleum resins".

In particular, the coexistence of a low-melting polymer such as atactic polypropylene in the pyrolysis raw material in a certain amount is preferable for carrying out the method of the present invention. That is, when the method of the present invention is carried out in a thermal decomposition apparatus, the polymer first melts and serves to assist the melting or subdivision of the thermal decomposition raw material polymer, which is a change that should occur prior to thermal decomposition. That is, as a result of the molten low melting point polymer closely adhering to the surface of the favorite thermal decomposition raw material polymer to effectively transfer thermal energy,
It can be expected to play a role in saving the energy required to melt the favourite polymer.

A particularly preferred halogen-free synthetic polymer as one of the decomposition raw materials in the method of the present invention is at least one polymer selected from polyolefins such as polyethylene and polypropylene and polystyrene, or a polymer containing these polymers as a main component. It is a composition.

As the halogen-containing synthetic polymer which is the other decomposition raw material of the method of the present invention, polyvinyl chloride (PV
Examples thereof include C), chloroprene rubber (CR), halogenated polyolefin such as chlorinated polyethylene, chlorinated polyethylene wax and the like.

Synthetic polymer which is a decomposition raw material of the method of the present invention (halogen-free synthetic polymer + halogen-containing synthetic polymer)
The content of the halogen-containing synthetic polymer is 50 with respect to the total amount of
It is selected to be not more than 25% by weight, preferably not more than 25% by weight.

<Inert Gas Used in the Method of the Present Invention> Any inert gas or vapor that does not react with the synthetic polymer may be used as the inert gas in contact with the melt or solution of the synthetic polymer in the method of the present invention. be able to. For example, hydrogen, helium, nitrogen, carbon dioxide, water vapor, methane, etc. can be mentioned. These gases or vapors can be used alone or as a mixture of two or more thereof. The inert gas may also contain other types of gases or vapors that are reactive with the synthetic polymer. In that case, the reaction of the reactive gas or vapor with respect to the synthetic polymer needs to be negligible. Preferred as the inert gas are nitrogen, carbon dioxide, combustion exhaust gas (also referred to as “combustion exhaust gas”) discharged from a boiler, and steam. However, since water vapor may corrode the equipment in some cases, nitrogen, carbon dioxide or combustion waste gas is more preferable for the decomposition treatment using the equipment having low corrosion resistance.
However, in the combustion waste gas, the oxygen concentration in the waste gas is sufficiently low, and the gas or vapor is not reactive with the melt or the solution of the synthetic polymer under the melting condition and the gas treatment condition. This is a prerequisite for use as an inert gas.

<Operating conditions of the method of the present invention> The temperature of the inert gas treatment for carrying out the method of the present invention (“melting temperature” in Table 1) is 100 to 450 ° C., preferably 150 to 400.
℃. Further, if the polymer does not melt at the processing temperature, a solvent can be used. Any solvent can be used as long as it does not react with the synthetic polymer. For example, in addition to high boiling point solvents such as sulfolane, lubricating oil, and heavy oil, liquid substances (decomposed oil) produced by the thermal decomposition reaction of the synthetic polymer can be used. When the treatment is performed on the polymer solution, it is also beneficial to use a pressure device (autoclave or the like) in order to suppress the volatilization of the solvent.

The method of contacting the melt or solution of the synthetic polymer, which is the decomposition raw material, with the inert gas includes a method of contacting by blowing an inert gas into the melt or solution (in-layer blowing method), A method in which an inert gas is caused to flow over the surface of the melt or solution (liquid level co-current method) to make contact, and a method in which the melt or solution is brought into contact with the flowing inert gas by dropping (liquid) Countercurrent flow method) can be exemplified. The order of the effects exhibited by these methods is usually a liquid surface co-current method, preferably an intra-layer blowing method, and more preferably a droplet countercurrent method.

The time for the inert gas treatment depends on the treatment temperature (the "melting temperature" in Table 1), but it is usually 5 minutes to 5 minutes.
h, preferably 10 min to 3 h. The flow rate of the inert gas is 10 to 10 ⁵ ml / min, preferably 50 to 10 ⁴ ml / min, converted to the standard state (N.T.P.) for 1 kg of the raw material,
More preferably, it is set to 100 to 10 ⁴ ml / min. This inert gas treatment may be carried out in a thermal decomposition apparatus to be described later, or may be carried out in an inert gas processing apparatus (column, tank, pipe or the like) provided separately from the thermal decomposition apparatus.

The thermal decomposition temperature of the method of the present invention varies depending on the kind of the synthetic polymer as the decomposition raw material, etc.
The temperature is set to 500 ° C, preferably 380 to 460 ° C.
In the method of the present invention, the oil component produced by thermal decomposition volatilizes at a high temperature in the thermal decomposition system, so that an oily substance can be collected by collecting and cooling this.

<Pyrolysis system of the method of the present invention> The thermal decomposition system of the melt or solution of the synthetic polymer treated by the method of the present invention may be, for example, a system using a batch type thermal decomposition apparatus.
A system using a complete mixing pyrolysis device or a system using a tubular (tubular) pyrolysis device may be used. It is also effective to proceed with the thermal decomposition while distilling off the low boiling point compound generated during the thermal decomposition. Further, in some cases, a pressure pyrolysis device using an autoclave is effective.

[0019]

EXAMPLES The method of the present invention will be specifically described below based on examples. However, the present invention is not so limited. In each of the following Examples and Comparative Examples, chlorine in the obtained oily substance was quantified by an electrotitration method. In addition, the flow rate of the inert gas is the standard state, that is, 0 ° C and 1 atm.
State, also known as N.T.P.

[0020]

EXAMPLE 1 A heat-resistant glass glass flask was fitted as an apparatus main body 2 equipped with a decomposition gas distillation outlet 21 in a heating furnace 1 as shown in FIG. 1 as an inert gas treatment and thermal decomposition apparatus, An inert gas introducing pipe 22 and a thermometer 2 were added to the flask 2.
3 and a screw-type stirrer 24 are installed, and polyvinyl chloride (PVC) 1000 ppm as a decomposition raw material 3 therein.
After charging 150 g of polypropylene (PP) in which is mixed, the synthetic polymer (synthetic resin) of the decomposition raw material 3 is melted by heating at 260 ° C. in the electric furnace 1, and then the resin is added while rotating the stirring blade 24. Nitrogen gas was blown into the melt 3 through the inert gas introducing pipe 22 at a flow rate of 100 ml / min for 1 hour.
In the next step, the melt 3 is heated to 420 ° C. to be thermally decomposed, and the generated decomposition gas is cooled in the cooler 4 while being distilled from the decomposition product distillation outlet 21 to be collected in the receiver 5. An oily product (140 g) was obtained. The chlorine content of this oily substance was 21 ppm according to a quantitative determination. The results are shown in Table 1.

[0021]

Comparative Example 1 In the apparatus of Example 1, 150 g of polypropylene containing 1000 ppm of polyvinyl chloride as the decomposition raw material 3 was heated to 260 ° C. and melted and stirred for 1 hour without blowing nitrogen gas. Next, the resin melt 3 is added to 4
It was heated to 20 ° C. for thermal decomposition and the generated decomposition gas was cooled in the cooler 4 and collected to obtain 138 g of an oily substance.
The chlorine content of this oil was 67 ppm according to a quantitative determination. The results are shown in Table 1.

[0022]

[Example 2] In the apparatus of Example 1, 150 g of polyethylene (PE) mixed with 800 ppm of polyvinyl chloride (PVC) as the decomposition raw material 3 was heated to 220 ° C and melted, while nitrogen gas was added thereto. Blow for 1 h at a flow rate of 250 ml / min. Next, the resin melt 3 was heated to 450 ° C. for thermal decomposition, and the generated decomposition gas was cooled and collected to obtain 133 g of an oily material. The chlorine content of this oily substance was 30 ppm according to a quantitative determination. The results are shown in Table 1.

[0023]

Comparative Example 2 Polyethylene 15 containing 800 ppm of polyvinyl chloride as the decomposition raw material 3 in the apparatus of Example 1
0 g was heated to 220 ° C. and stirred for 1 h while melting.
Next, the resin melt 3 was heated to 450 ° C. for thermal decomposition, and the generated decomposition gas was cooled and collected to obtain 125 g of an oily substance. The chlorine content of this oil is 13
It was 0 ppm. The results are shown in Table 1.

[0024]

[Example 3] In the apparatus of Example 1, 150 g of polystyrene (PS) mixed with 1000 ppm of polyvinyl chloride (PVC) as the decomposition raw material 3 was heated to 300 ° C and melted, while being melted in the resin melt 3. Nitrogen gas flow rate 20ml / min
I blew it for 1 hour. Next, the melt 3 was heated to 390 ° C. for thermal decomposition, and the generated decomposition gas was cooled and collected to obtain 138 g of an oily product. The chlorine content of this oily substance was found to be 29 ppm. The results are shown in Table 1.

[0025]

[Comparative Example 3] Polystyrene 1 containing 1000 ppm of polyvinyl chloride as decomposition raw material 3 in the apparatus of Example 1
50 g was heated to 300 ° C. and stirred for 1 h while melting. Next, the resin melt 3 is heated to 390 ° C. for thermal decomposition, and the generated decomposition gas is cooled and collected to give an oily substance 13.
5 g was obtained. The chlorine content of this oily substance was 70 ppm according to a quantitative determination. The results are shown in Table 1.

[0026]

[Embodiment 4] Polyethylene 1 containing 1000 ppm of polyvinyl chloride as a decomposition raw material 3 in the apparatus of Embodiment 1.
Carbon dioxide gas was blown into the resin melt 3 at a flow rate of 150 ml / min for 1 hour while heating and melting 50 g at 240 ° C. Next, the melt 3 is heated to 450 ° C. to be thermally decomposed, and the generated decomposition gas is cooled and collected to obtain an oily substance 12.
8 g were obtained. The chlorine content of this oily substance was determined to be 33 ppm. The results are shown in Table 1.

[0027]

Example 5 150 g of polyethylene was placed in a heat-resistant glass flask equipped with a reflux condenser and heated to 450 ° C.
Pyrolysis gradually progressed to form a low boiling point substance, and the reaction temperature dropped to 400 ° C. after 30 minutes. This product was used as a solvent in the apparatus of Example 1, and the decomposition raw material 3 was added to the solvent.
As an example, add 150 g of polyethylene mixed with 1000 ppm of polyvinyl chloride and heat it to 180 ° C to dissolve it. Carbon dioxide gas will flow into the resulting solution at a flow rate of 50 ml / min.
I blew it for 1 hour. Next, the resin solution was heated to 450 ° C. for thermal decomposition, and the generated decomposition gas was cooled and collected to obtain 228 g of an oily substance. The chlorine content of the obtained oily substance was 18 ppm according to the determination. The results are shown in Table 1.

[0028]

[Embodiment 6] Polyethylene 1 containing 1000 ppm of polyvinyl chloride as a decomposition raw material 3 in the apparatus of Embodiment 1.
While 50 g was heated to 240 ° C. to be melted, water was injected into the resin melt 3 at a flow rate of 0.08 ml / min for 1 h. The water was heated in the introduction tube to become steam, which was blown into the resin melt. The flow rate of water vapor was 100 ml / min (standard state conversion). Next, the melt 3 was heated to 450 ° C. for thermal decomposition, and the generated decomposition gas was cooled and collected to obtain 128 g of an oily substance. According to a quantitative determination, the chlorine content of the obtained oily substance was 35 ppm. The results are shown in Table 1.

[0029]

[Embodiment 7] Polyethylene 1 containing 1000 ppm of polyvinyl chloride as decomposition raw material 3 in the apparatus of Embodiment 1.
Boiler waste gas was introduced into the resin melt 3 at a flow rate of 100 ml / min for 1 hour while heating and melting 50 g at 240 ° C. This boiler waste gas contained 4% oxygen, but did not show reactivity with polyethylene enough to burn polyethylene. Then, melt 3
When heated to 0 ° C. for thermal decomposition, the generated decomposition gas was cooled and collected to obtain 128 g of an oily substance. The chlorine content of the obtained oily substance was 18 ppm according to the determination. The results are shown in Table 1.

[0030]

[Embodiment 8] In the apparatus of Embodiment 1, 30 g of polyvinyl chloride and 120 g of polyethylene as the decomposition raw material 3 are heated to 260 ° C. to be melted, and nitrogen gas is blown into the resin melt 3 at a flow rate of 100 ml / min for 1 hour. It is. Next, the melt 3
Was heated to 450 ° C. for thermal decomposition, and the generated decomposition gas was cooled and collected to obtain 110 g of an oily substance. According to a quantitative determination, the chlorine content of the obtained oily substance was 99 ppm.
The results are shown in Table 1.

[0031]

Comparative Example 4 The procedure of Example 8 was repeated except that nitrogen gas was not blown into the polymer melt to obtain 108 g of an oily substance. The chlorine content in the oil was 684 ppm. The results are shown in Table 1.

[0032]

[Example 9] The same procedure as in Example 1 was repeated except that nitrogen gas was blown into the polymer melt at the flow rate of 500 ml / min, instead of blowing nitrogen gas into the polymer melt. 126 g of an oil was obtained. The chlorine content of this oily substance was 34 ppm. The results are shown in Table 1.

[0033]

[Embodiment 10] 150 g of polyethylene having 1000 ppm of polyvinyl chloride mixed therein is charged as a decomposition raw material 3 into the bottom portion 6b of the tower type inert gas treatment apparatus (abbreviated as "tower apparatus") 6 shown in FIG. Then, the decomposition raw material 3 was heated to 360 ° C. by the heating furnace 1 surrounding the bottom portion 6b of the apparatus 6 and melted. The melt 3 is passed through a melt feed pipe 61 to form a tower type device 6
Of the sparger 62 attached to the end 61e of the melt feed line in the top 6t.
From the melt droplets 3d. A flow rate of nitrogen gas is 500 ml from an inert gas introduction pipe 63 provided on the side wall above the liquid surface of the melt 3 in the middle stage 6 m of the tower type device 6.
/ min. The introduced nitrogen gas is a droplet 7
After being brought into countercurrent contact with d, it was discharged out of the apparatus through an inert gas discharge pipe 64 provided at the top 6t of the tower type apparatus 6. After continuing this inert gas treatment for 10 minutes, the melt 3 was transferred to the apparatus of Example 1 (FIG. 1), heated to 450 ° C., and pyrolyzed to collect the decomposed gas by cooling. As a result, 133 g of an oily matter was obtained. The chlorine content of the obtained oily substance was 7 ppm. The results are shown in Table 1.

[0034]

Example 11 The procedure of Example 1 was repeated except that the conditions for treating the molten polymer with nitrogen gas were changed as follows, yielding 116 g of an oily substance.
The chlorine content of the obtained oily substance was 1 ppm: Melting temperature: 360 ° C .; Inert gas treatment time: 2 h; Nitrogen gas flow rate: 500 ml / min. The results are shown in Table 1.

[0035]

Example 12 The procedure of Example 1 was repeated except that the halogen-containing polymer mixed was changed to polyvinylidene chloride (PVDC), and 139 g of an oily product was obtained. The chlorine content of the obtained oily substance was 13 ppm. The results are shown in Table 1.

[0036]

EFFECTS OF THE INVENTION According to the method of the present invention, the following various effects can be achieved together: (1) Suppression of the generation of organic chloride when the synthetic polymer is thermally decomposed to produce an oily substance. Thereby, the chloride content in the decomposed oily substance can be remarkably reduced. (2) Applicable to a wide range of pyrolytic raw material polymers, even if it is a cracked oil obtained from a synthetic polymer in which chloride polymers such as polyvinyl chloride and chlorinated polyethylene are mixed, fuel oil and raw material oil It becomes possible to use it as such. (3) Even when a conventional thermal decomposition apparatus is used, it can be applied by adding an inert gas treatment apparatus without modifying the thermal decomposition apparatus itself.

[0037]

[Table 1]

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of an example of an inert gas treatment and thermal decomposition apparatus useful for carrying out the method of the present invention.

FIG. 2 is a schematic vertical cross-sectional view of another example of an inert gas treatment apparatus useful for carrying out the former stage of the method of the present invention.

[Explanation of symbols]

1 Heating Furnace 2 Main Body of Inert Gas Treatment and Thermal Decomposition Device Useful for Carrying Out Method of the Present Invention 3 Melt of Synthetic Polymer as Decomposition Raw Material 4 Cooler for Cooling Decomposition Gas 5 Cooling of Decomposition Gas Receptor for oil collected by 6 Alternative example of inert gas treatment device useful for carrying out the first stage of the method of the present invention 21 Decomposition gas distillation outlet 22 Inert gas introduction pipe 23 Thermometer 24 Screw type stirring Vessel 61 melt feed pipe line 62 sparger 63 inert gas inlet pipe 64 inert gas discharge pipe 3d melt droplets 6b bottom of inert gas treatment device 6m middle stage of inert gas treatment device 6t inert gas treatment device Top of 61e End of melt feed line

Continuation of the front page (72) Inventor Noriyuki Hirowata 6-2 1-2 Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Mitsui Petrochemical Industry Co., Ltd.

Claims (14)

[Claims] 1. An inert gas is added to a synthetic polymer after a mixture of a halogen-containing synthetic polymer and a halogen-free synthetic polymer is melted or heated and dissolved in a solvent, or when heated in parallel therewith. A method for producing an oily substance by thermal decomposition of a synthetic polymer, which comprises substantially removing a halide liberated by contacting and then thermally decomposing the melt or solution to form an oily substance. 2. The method for producing an oily product according to claim 1, wherein a gas containing nitrogen or carbon dioxide as a main component is used as the inert gas. 3. The method for producing an oily product according to claim 1, wherein steam containing steam as a main component is used as the inert gas. 4. The method for producing an oily product according to claim 1, wherein combustion waste gas is used as the inert gas. 5. A synthetic polymer containing no halogen is at least one selected from polyolefin and polystyrene.
The method for producing an oily substance according to any one of claims 1 to 4, which is a polymer of one kind or a polymer composition containing these polymers as a main component. 6. The method for producing an oily product according to claim 1, wherein the halogen-containing synthetic polymer is at least one selected from polyvinyl chloride, polyvinylidene chloride and chlorinated polyethylene. 7. The content ratio of the halogen-containing synthetic polymer in the total synthetic polymer is 50% by weight or less.
7. The method for producing an oily product according to any of 6. 8. The method for producing an oily product according to claim 1, wherein the inert gas comes into contact with the melt or the solution of the synthetic polymer by flowing over the surface of the melt or the solution. . 9. The method for producing an oily product according to claim 1, wherein the melt or solution of the synthetic polymer is brought into contact with an inert gas by being dropped into a flowing inert gas. 10. The method according to claim 1, wherein the contact between the melt or solution of the synthetic polymer and the inert gas is carried out by blowing an inert gas into the melt or solution of the polymer. Method for producing oily substance. 11. The method for producing an oily product according to claim 1, wherein the flow rate of the inert gas is 10 to 10 ⁵ (standard state conversion) ml / min per 1 kg of the synthetic polymer. 12. The method for producing an oily product according to claim 1, wherein the flow rate of the inert gas is 100 to 10 ⁴ (standard state conversion) ml / min per 1 kg of the synthetic resin. 13. The method for producing an oily product according to claim 1, wherein the melt or solution of the synthetic polymer and the inert gas are contacted at a temperature of 150 ° C. to 400 ° C. 14. The method for producing an oily product according to claim 1, wherein the solvent dissolving the synthetic polymer is a low temperature fluidized oil produced by thermal decomposition of the synthetic polymer.