JPH09227877A - Method for converting waste plastic into oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for converting waste plastics into oils while preventing the oils from being contaminated with organic acids. SOLUTION: This method comprises heat-decomposing waste plastics by heating to 400-500 deg.C, passing the vaporous product formed by the heat decomposition over a solid acid catalyst 8 heated to 400-500 deg.C to effect the secondary heat decomposition and passing the vaporous product subjected to the secondary heat decomposition over a catalyst 8' prepared by dispersing a metal (e.g. platinum, palladium or a mixture thereof) in a support comprising alumina, silica or activated coal and heated to 400-500 deg.C to effect the tertiary heat 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 oil treatment of waste plastics, and more particularly to a method for oil treatment of waste plastics for preventing the contamination of organic acid.

[0002]

2. Description of the Related Art From the viewpoint of preserving the global environment and creating new energy resources, research has been actively conducted to decompose waste oil into oil by using a catalyst and use it as fuel oil.

Although waste plastics can be liquefied by simple thermal cracking without using a catalyst, the temperature required for cracking is high, and the cracked oil produced contains a large amount of olefins which are unfavorable for storage as fuel. Research has been suspended for reasons such as.

The decomposition of waste plastics using a catalyst is called catalytic decomposition, and most of the research is on polyolefins such as polyethylene (PE) and polypropylene (PP), or polystyrene (PS).

Further, these waste plastics are industrial waste plastics discharged in the production process of the factory and contain almost no impurities other than carbon and hydrogen.

[0006]

However, many plastic products are integrated with wood and paper products with an adhesive, etc., and waste plastics discharged from ordinary households, shops, supermarkets, etc. are other than carbon and hydrogen. Contains a large amount of impurity elements such as oxygen and nitrogen.

Therefore, when general waste plastic is catalytically decomposed, these impurity elements (particularly oxygen) participate in the reaction to produce organic acids.

When an organic acid is present in the produced oil, it acts as a catalyst and accelerates the polymerization of olefins contained in the oil in a small amount, which may increase the viscosity of the oil and cause it to solidify. As a result, there is a problem that it is not preferable for storage and use.

The present invention uses a two-step catalytic cracking method in which a steam product generated by thermal decomposition is catalytically decomposed and oiled by a usual solid acid catalyst, and then organic acids contained in the oil are decomposed. It is an object of the present invention to provide an oil treatment method for waste plastics, which removes organic acids present in oil.

[0010]

In order to achieve the above object, the method for oil treatment of waste plastics according to the present invention comprises heating the waste plastics to thermally decompose them, and generating a vapor product generated by the thermal decomposition as a solid acid. The secondary thermal decomposition treatment is carried out by passing through the catalyst, and then the tertiary thermal decomposition treatment is carried out by passing through a catalyst containing at least one of platinum and palladium metals.

The waste plastic oil treatment method of the present invention heats the waste plastic to thermally decompose it, and the vapor product generated by the thermal decomposition is passed through a solid acid catalyst for secondary heat decomposition treatment. After that, a tertiary thermal decomposition treatment is carried out by passing through a catalyst containing at least one of transition metal oxides of manganese oxide, iron oxide, nickel oxide, and cobalt oxide.

Further, in the method for oil treatment of waste plastics of the present invention, the waste plastics are heated in the range of 400 ° C to 500 ° C to be thermally decomposed, and the steam product generated by the thermal decomposition is heated to 400 ° C to 500 ° C. Secondary pyrolysis treatment is carried out by passing through a heated solid acid catalyst, and then alumina, silica,
Alternatively, 400 formed by platinum or palladium metal alone or mixed and dispersed in a carrier made of activated carbon.
The third thermal decomposition treatment is carried out by passing the catalyst heated to ℃ to 500 ℃.

In the method for oil treatment of waste plastics of the present invention, the waste plastics are heated in the range of 400 ° C to 500 ° C to be thermally decomposed, and the steam product generated by the thermal decomposition is heated to 400 ° C to 500 ° C. Secondary pyrolysis treatment is carried out by passing through a heated solid acid catalyst, and then alumina, silica,
Or 400 ° C. formed by dispersing a transition metal oxide of manganese oxide, iron oxide, nickel oxide, or cobalt oxide in a carrier made of activated carbon, alone or in a mixture.
The catalyst is heated in the range of 500 ° C. and is subjected to a tertiary thermal decomposition treatment.

In the method for oil treatment of waste plastics according to the first to fourth aspects, the waste plastics are polyolefin-based plastic wastes and contain impurity elements such as oxygen and nitrogen.

In the catalytic oiling of general waste plastics, a solid acid catalyst is used to catalytically oil, and then the organic acids in the oil are decomposed and removed by the catalyst described in the following item 2 to obtain a catalytic oil. I will provide a.

Also provided is a catalyst in which metals such as platinum and palladium are dispersed alone or in a mixture on the surface of alumina, silica, activated carbon or the like.

Also provided is a catalyst in which a transition metal oxide such as manganese oxide, iron oxide, nickel oxide or cobalt oxide is dispersed alone or in a mixture on the surface of alumina, silica, activated carbon or the like.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for oil treatment of waste plastics according to the present invention, waste plastics are heated to be thermally decomposed, and steam products generated by the thermal decomposition are passed through a solid acid catalyst to generate secondary heat. It is decomposed, and then it is passed through a catalyst containing at least one of platinum and palladium metals to carry out a tertiary thermal decomposition treatment, or waste plastics are heated to be thermally decomposed and then subjected to thermal decomposition. The generated vapor product is passed through a solid acid catalyst for secondary pyrolysis, and then a catalyst containing at least one of transition metal oxides of manganese oxide, iron oxide, nickel oxide, and cobalt oxide. The third thermal decomposition treatment is carried out by passing through.

In this method for oil treatment of waste plastics, the target is waste plastics, preferably polyolefin plastic wastes, and in addition to carbon and hydrogen, impurity elements such as oxygen and nitrogen. More preferably, the main component is PE, and a small amount of PP, PS, polycarbonate, polyethylene terephthalate (PET), polyamide, etc. are also included, and fibrin that cannot be separated is also included. [In addition, polyvinyl chloride (P
It is desirable that VC) be sorted and excluded. Approximately 50% of the weight of polyvinyl chloride is chlorine, and a large amount of hydrogen chloride is generated by catalytic cracking, which reacts with hydrocarbons during catalytic cracking at high temperatures, which can affect the human body and the natural environment. This is to eliminate the possibility of producing harmful chlorides or the cause of corrosion or damage to the catalytic cracking device. ].

Further, the waste plastics are heated at 400 ° C. to 5 ° C.
The melting point of polyethylene, the main component of waste plastics, is 420 ° C when it is heated and decomposed by heating in the range of 00 ° C.
This is because

The catalytic conversion of waste plastics with a solid acid catalyst is excellent in hydrocarbon cracking performance, and the temperature range of the solid acid catalyst is 400 ° C to 5 ° C.
The reason why the temperature is set to 00 ° C. is that the decomposition proceeds further and the amount of gas components increases at higher temperatures.

A catalyst containing at least one of metals of platinum and palladium, or at least one of transition metal oxides of manganese oxide, iron oxide, nickel oxide and cobalt oxide. The reason why the temperature range of the catalyst including is set to 400 ° C. to 500 ° C. is that at higher temperature, the decomposition further proceeds and the amount of gas components is increased.

The solid acid catalyst used in the present invention is
Silica / alumina-based catalyst, for example, calcined product of silica / alumina at 450 ° C. to 550 ° C., alumina / silicic acid-based catalyst,
A silicic acid / iron oxide type catalyst, for example, zeolite, more specifically, HZSM5.

The metal catalyst contains any one of platinum and palladium, and more specifically, platinum or palladium metal on a carrier made of alumina, silica or activated carbon. Are formed alone or mixed and dispersed.

The transition metal oxide catalyst contains at least one of manganese oxide, iron oxide, nickel oxide, and cobalt oxide, and more specifically, alumina, silica, or It is formed by dispersing transition metal oxides of manganese oxide, iron oxide, nickel oxide, or cobalt oxide alone or in a mixture on the surface of activated carbon.

An embodiment of the present invention will be described below.

Example 1 A catalytic decomposition experiment of waste plastics according to the present invention was carried out by the apparatus shown in FIG. The reactor (7) was a stainless tube with a diameter of 25 mm and a length of 300 mm, the bottom of which was filled with 15 grams of waste plastic sample.

The waste plastic sample is obtained by separating and removing PVC from the waste plastic collected at the supermarket using a hydrocyclone (difference in specific gravity in water), and then separating the adhered fibrous materials such as wood chips and paper materials with a disperser.・ Classified.

On a 10 mm top of the waste plastic sample, 1.5 grams of solid acid catalyst (8), eg, silica-alumina or zeolite (HZSM5), is also placed on a further 10 mm top of this solid acid catalyst (8). , A catalyst (8 ') for decomposing organic acids was installed.

This reactor (7) was placed in an electric furnace (5) heated to about 400 ° C. for catalytic cracking. All the pipes around the reactor (7) are stainless pipes having a diameter of 6 mm, and nitrogen gas is blown from the lower part of the reactor (7) at a flow rate of 50 ml / min.

As a result, the vapor product of the waste plastic melted at the bottom of the reactor (7) becomes a solid acid catalyst (8),
It is transported to the catalyst (8 '). The vapor product decomposed and produced by the two-stage solid acid catalyst (8) and the catalyst (8 ′) is
It is liquefied in the cooling tower (9) cooled to about 5 ° C and collected in the collector (10).

The collected product oil (carbon number: 5 to 20) was quantified and its composition was analyzed by gas chromatography.

The solid oil (carbon number: 21 or more) deposited in the cooling tower (9) was extracted with hexane after the reaction was completed,
It was quantified as a wax content. The reaction was carried out for about 4 hours, and residuals remaining as unreacted components in the reactor (7) after completion of the reaction were also extracted and quantified with hexane.

The produced gas component was calculated from the difference between the gas meters (3) installed before and after the reactor (7).
The main components of the produced gas were propylene and butene, as well as methane, ethane and ethylene.

(Example 2) [Quantification and composition of produced oil] Using the apparatus of Example 1, as a catalyst for decomposing an organic acid, that is, a catalyst (8 ') for metals, for example, activated carbon was used.
A catalyst in which 5% by weight of palladium is dispersed (hereinafter referred to as "Pd-
(C) (abbreviated as "C") was installed, and the result of contact oiling at about 400 ° C is shown in FIG.

For reference, FIG. 2 also shows the results of the case of using only the one-step catalyst without using the organic acid decomposition catalyst and the results of the simple thermal decomposition without using the catalyst.

From these results, it was found that when the two-stage catalyst was used, the oil production rate was slightly reduced, but the composition was not significantly different from that of the case where only the one-stage catalyst was used. However, the oil produced by simple thermal decomposition or only the first-stage catalyst was black and had an irritating odor, whereas when the two-stage catalyst was used, a slightly yellowish odorless transparent oil was produced.

In addition, it is presumed that in the oil obtained by simple thermal decomposition or only the one-step catalyst, blackening progresses with the lapse of storage time, and a considerable amount of tar is produced in the oil.

(Example 3) [Measurement of viscosity of produced oil] The viscosity of the oil of Example 2 produced by simple thermal decomposition, first-stage and two-stage catalytic cracking was measured. As a result, as shown in FIG. 3, the produced oil obtained by simple thermal cracking or one-step catalytic cracking has a slightly high viscosity from the beginning, and the viscosity value tends to increase with the passage of time.

On the other hand, Pd-C, Mn ₂ O ₃ / Al ₂ O ₃ , C
In the oil using o ₃ O ₄ / Al ₂ O ₃ as the second-stage catalyst, the tendency of increasing the viscosity is remarkably reduced.

The increase in viscosity is due to the polymerization of the olefin component in the produced oil, and one of the components that accelerates the polymerization of olefin is an organic acid. Therefore, among the produced oils obtained in Example 2, the offensive odor of the oil obtained by the simple thermal decomposition and the one-step catalytic cracking method is due to the organic acid (and the phenol derivative). It was concluded that the olefin component in the oil was polymerized and a remarkable increase in viscosity was observed.

On the other hand, in the two-stage catalytic pyrolysis, the Pd-C catalyst installed in the second stage contributes to the decomposition of the organic acid and removes the organic acid in the oil, and it is considered that the polymerization of the olefin component is suppressed. .

(Example 4) [Decomposition of Organic Acid in Produced Oil] The produced oil contains organic acids such as formic acid, acetic acid, and propionic acid, but their amounts have not been quantified. However, since organic acids have a unique infrared absorption band due to the (COO) group, their relative amount can be measured spectroscopically.

FIG. 4 shows the infrared absorption spectrum of the product oil obtained in Example 2. Of these, the above (C
The absorption by the (OO) group is around 1715 cm ^-1 , and the absorption due to the (CH ₂ ) group peculiar to the aliphatic hydrocarbon is 13
It is observed near 75 cm ^-1 .

Therefore, the concentration of the organic acid in the produced oil was relatively determined by calculating the peak intensity ratio. The results for the oil obtained in Example 2 are shown in FIG.

(Example 5) [Two-step catalytic cracking with various catalysts] From the results of Example 4, the catalyst effective for decomposing the organic acid in the produced oil has a remarkably small initial viscosity value of the produced oil. Admitted.

Therefore, the first stage catalyst, that is, the solid acid catalyst (8) is fixed to, for example, silica-alumina, and the second stage catalyst [metal catalyst (8 '), transition metal oxide catalyst] is used. (8 ')] was variously examined. FIG. 6 shows the result.

From these results, it can be seen that manganese oxide and cobalt oxide, which produce oil having a small peak intensity ratio and a small initial viscosity, are promising catalyst components. Further, although silica or alumina may be used as the carrier, it is considered that alumina is rather superior in performance.

However, compared with these, it is considered that the formation of the polymer has already started because the oil produced by the platinum catalyst contains a considerable amount of organic acid and the initial viscosity is also high.

[0050]

EFFECT OF THE INVENTION The method for oil treatment of waste plastics of the present invention heats the waste plastics for thermal decomposition, and the steam products generated by the thermal decomposition are passed through a solid acid catalyst for secondary thermal decomposition treatment. After that, at least platinum and palladium is passed through a catalyst containing any one of metals, and the tertiary thermal decomposition treatment is carried out. Therefore, it is possible to prevent mixing of organic acids, and to provide a useful liquid fuel. be able to.

The waste plastic oil treatment method of the present invention heats the waste plastic to thermally decompose it, and the vapor product generated by the thermal decomposition is passed through a solid acid catalyst to undergo a second thermal decomposition treatment. After that, since the tertiary thermal decomposition treatment is carried out by passing through a catalyst containing at least one of transition metal oxides of manganese oxide, iron oxide, nickel oxide, and cobalt oxide, it is possible to prevent mixing of organic acids. It is possible to provide a useful liquid fuel.

In the method for oil treatment of waste plastics of the present invention, the waste plastics are heated in the range of 400 ° C to 500 ° C to be thermally decomposed, and the steam product generated by the thermal decomposition is heated to 400 ° C to 500 ° C. Secondary pyrolysis treatment is carried out by passing through a heated solid acid catalyst, and then alumina, silica,
Alternatively, 400 formed by platinum or palladium metal alone or mixed and dispersed in a carrier made of activated carbon.
Since the third thermal decomposition treatment is carried out by passing the catalyst heated to ℃ to 500 ℃, it is possible to prevent mixing of organic acids, it is possible to provide a useful liquid fuel.

In the method for oil treatment of waste plastics of the present invention, the waste plastics are heated in the range of 400 ° C to 500 ° C to be thermally decomposed, and the steam product generated by the thermal decomposition is heated to 400 ° C to 500 ° C. Secondary pyrolysis treatment is carried out by passing through a heated solid acid catalyst, and then alumina, silica,
Or 400 ° C. formed by dispersing a transition metal oxide of manganese oxide, iron oxide, nickel oxide, or cobalt oxide in a carrier made of activated carbon, alone or in a mixture.
Since the tertiary thermal decomposition treatment is carried out by passing the catalyst heated in the range of 500 ° C., it is possible to prevent the organic acid from being mixed in and provide a useful liquid fuel.

[Brief description of drawings]

FIG. 1 shows a schematic device for carrying out an oil treatment method for waste plastic according to an embodiment of the present invention.

FIG. 2 shows experimental results based on Example 2.

FIG. 3 shows the viscosity measurement results of the produced oil.

FIG. 4 shows an infrared absorption spectrum of the produced oil.

FIG. 5 shows a peak intensity ratio.

FIG. 6 shows the search results for the second-stage catalyst.

[Explanation of symbols]

 8 Solid acid catalysts 8'Catalysts of metals (catalysts of transition metal oxides)

Front page continued (72) Inventor Akira Ueno 3-5-1, Johoku, Hamamatsu City, Shizuoka Shizuoka University Faculty of Engineering (72) Inventor Tamaki Hirose 3-5-1, Kitakita, Hamamatsu City, Shizuoka Prefecture Undergraduate (72) Inventor Sana Horikawa Sakae 3-5-1, Shirokita, Hamamatsu City, Shizuoka Prefecture Faculty of Engineering, Shizuoka University (72) Inventor Tsutomu Sakai 1090-14 Hatori, Shizuoka City, Shizuoka Prefecture Nippon Kakko Co., Ltd. (72 ) Inventor Takeshi Kanazawa 191 Yuzuki, Shizuoka City, Shizuoka Prefecture Aikawa Iron Works Co., Ltd.

Claims (5)

[Claims] 1. A waste plastic is heated and thermally decomposed, and a vapor product generated by the thermal decomposition is passed through a solid acid catalyst to be subjected to a secondary thermal decomposition treatment, and then at least one of platinum and palladium metals is used. A method for oil treatment of waste plastics, which comprises subjecting a catalyst containing any one of them to a third pyrolysis treatment. 2. A waste plastic is heated to be pyrolyzed, and a vapor product generated by the pyrolysis is passed through a solid acid catalyst to be subjected to secondary pyrolysis, and then at least manganese oxide, iron oxide, nickel oxide. A method for oil treatment of waste plastic, which comprises subjecting a catalyst containing any one of transition metal oxides of cobalt oxide to a tertiary pyrolysis treatment. 3. A waste plastic is heated in the range of 400 ° C. to 500 ° C. to be thermally decomposed, and a steam product generated by the thermal decomposition is 400 ° C. to 500 ° C.
A secondary thermal decomposition treatment is carried out by passing through a solid acid catalyst heated to 400 ° C., and then platinum or palladium metal is dispersed alone or in a mixture of 400 in a carrier composed of alumina, silica, or activated carbon. A method for oil treatment of waste plastics, characterized in that a tertiary heating decomposition treatment is carried out by passing a catalyst heated to 500 to 500 ° C. 4. A waste plastic is heated in the range of 400 ° C. to 500 ° C. to be thermally decomposed, and a vapor product generated by the thermal decomposition is 400 ° C. to 500 ° C.
Secondary thermal decomposition treatment by passing through a solid acid catalyst heated to, then, alumina, silica, or a transition metal oxide of manganese oxide, iron oxide, nickel oxide, or cobalt oxide alone on a carrier made of activated carbon, Alternatively, a method for oil treatment of waste plastics is characterized in that a catalyst heated in a range of 400 ° C. to 500 ° C., which is formed by mixing and dispersing, is passed through to carry out a third pyrolysis treatment. 5. The method for oil treatment of waste plastic according to claim 1, wherein the waste plastic is polyolefin plastic waste and contains impurity elements such as oxygen and nitrogen.