JP2008266452A - Method and apparatus for thermal decomposition of waste plastic - Google Patents

Abstract

The present invention provides a method for producing a thermal decomposition product having high utility value from waste plastic as compared with conventional waste plastic oil production method and waste plastic gasification method.
A pyrolysis step in which waste plastic is pyrolyzed to generate pyrolysis gas, and heat that cools the generated pyrolysis gas to condense oily components in the pyrolysis gas to generate pyrolysis oil. In the method for pyrolyzing waste plastics having a cracked oil production step, the reaction temperature of the pyrolysis step is set to 650 ° C. ± 20 ° C., and an oily component in the pyrolysis gas condensed in the pyrolysis oil recovery step has a flash point of 60. It is characterized in that it is an oily component having a flash point of 70 ° C or higher.
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Description

  The present invention relates to a waste plastic thermal decomposition method and thermal decomposition apparatus for effectively using waste plastic as a resource.

  Conventionally, waste plastic treatment methods have been centered on simple incineration and landfilling, but the promotion of a recycling-oriented society has become a major social issue in recent years, so there is a strong demand for effective technology for waste plastics. Thus, as waste plastic treatment methods for the purpose of effective use of waste plastic, a waste plastic oil conversion method for recovering oil from waste plastic and a waste plastic gasification method for recovering combustible gas from waste plastic have been proposed.

  For example, as described in Patent Documents 1 to 3, the waste plastic oil production method generates a pyrolysis gas by charging waste plastic into a pyrolysis furnace having a reaction temperature of about 400 ° C. The gas is introduced into a catalyst reforming tower packed with a catalyst such as zeolite in the subsequent stage to decompose the oily components in the pyrolysis gas in the catalyst tower to lighten, and the pyrolysis gas after passing through the catalyst reforming tower is reduced. This is a method of condensing and recovering pyrolysis oil by cooling with a gas cooling device, and fractionating the recovered pyrolysis oil into a specific boiling fraction and then using it as fuel oil or the like.

On the other hand, in the waste plastic gasification method, as described in Patent Documents 4 to 6, for example, the waste plastic is directly blown into a high-temperature gasification furnace having a reaction temperature of about 1000 ° C to 1500 ° C, or the waste plastic is heated. Once pyrolyzed and gasified in the cracking furnace, it is blown into the gasification furnace to cause cracking reaction, partial combustion reaction with oxygen, steam reforming reaction, etc. in the high temperature gasification furnace, and the waste plastic is carbon monoxide ( This is a method of converting to a combustible gas mainly composed of CO) and hydrogen (H ₂ ).
“Boiler Research” No. 171, page 7, lines 14-15 (1978) JP-A-6-128569 JP-A-3-86790 JP 59-174690 A JP 10-156314 A Japanese Patent Laid-Open No. 10-281437 JP 2004-67896 A

However, as an issue with the existing waste plastic oil conversion method, the existing waste plastic oil conversion method is to convert waste plastic containing polyethylene resin including container and packaging plastics (hereinafter referred to as “capacity plastic”) into oil. In other words, oils mainly composed of long-chain aliphatic hydrocarbons having the property of solidifying when the liquid temperature is lowered such as in winter can be mentioned. Since the maximum viscosity that can be transferred by the liquid feed pump is usually about 1000 mm ² / s (about 1000 cSt) as described in Non-Patent Document 1, for example, the kinematic viscosity is 1000 mm ² / s or less (1000 cSt or less). In order to do so, it is necessary to add a heating facility to an oil transfer facility such as a liquid feed pump or a liquid feed pipe or a combustion facility where waste plastic oil is used, which is not industrially practical. Therefore, in the existing waste plastic oil conversion method, as described above, a catalytic reforming tower is provided at the rear stage of the pyrolysis furnace, and after the lightening of long-chain aliphatic hydrocarbons in the pyrolysis gas, the pyrolysis oil is recovered. Is adopted. However, as a problem with the method of recovering pyrolysis oil lightened from long-chain aliphatic hydrocarbons by catalytic reforming tower, the pyrolysis oil produced is low boiling oil such as gasoline, kerosene, diesel oil, etc. A new problem arises because it becomes the main component. In other words, combustion devices that use gasoline, kerosene, or light oil as fuels are subject to severe quality restrictions on fuel properties, so that pyrolytic oil produced from waste plastics containing various impurities can be used as an alternative to gasoline, kerosene, and light oil. The addition of high-precision distillation and high-precision refining requires equipment costs and operating costs. Gasoline, kerosene, and light oil are very difficult to handle because of their very low flash point, and facilities that require heavy specifications for peripheral equipment such as storage containers and transfer equipment for pyrolysis oil Cost increases. These problems of the conventional plastic waste oil technology have become a major factor in the fact that the waste plastic oil technology has hardly spread as an actual plant.

On the other hand, the problem with the existing waste plagasification method is that the product gas obtained by the existing waste plagasification method contains carbon monoxide (CO) and hydrogen (H ₂ ) as the main components, so that the gas calorie is 2000 It is as low as about ˜2500 kcal / Nm ³ (about 8300 to 10500 kJ / Nm ³ ), and the utility value when the product gas is used as fuel gas is low.

  Therefore, the present invention recovers oil that can be transferred from waste plastic even at a low temperature of 0 ° C., corresponding to A heavy oil or third petroleum, which has a higher utility value than conventional waste plastic oil production methods and waste plastic gasification methods. It aims to provide a method.

As a result of intensive studies on a method for producing a product having a higher utility value than waste plastic oil conversion and waste plastic gasification from waste plastic, the present inventors have made the waste plastic a reaction temperature of 650 ° C. ± 20 ° C. After pyrolysis treatment in the adjusted pyrolysis furnace to generate pyrolysis gas, the generated pyrolysis gas is introduced into the pyrolysis oil generator to cool the pyrolysis gas, and the ignition contained in the pyrolysis gas By condensing and recovering an oily component having a point of 60 ° C. or higher or a flash point of 70 ° C. or higher, the kinematic viscosity at low temperature is 1000 mm ² / s or less (1000 cSt or less, measurement method JIS-K2283) even at a liquid temperature of 0 ° C. It has been found that it is possible to produce a pyrolysis oil having properties equivalent to heavy oil A, which is low and has less quality restrictions than gasoline, kerosene and light oil and has a wide range of industrial applications. Incidentally, when the reaction temperature is about 600 ° C. or about 700 ° C., the kinematic viscosity at the liquid temperature of 0 ° C. rapidly increases to 2000 mm ² / s or more (2000 cSt or more), which is a problem of the conventional waste plastic oil production method. It was also found that a certain low temperature viscosity problem cannot be solved.

  Moreover, as a result of investigating the cause of the specific formation of pyrolysis oil with low low temperature viscosity when the reaction temperature of the pyrolysis furnace is about 650 ° C., 1) Undecomposed in the pyrolysis oil up to about 600 ° C. That the long-chain aliphatic hydrocarbons remain, the low-temperature viscosity is inhibited even if a small amount of the long-chain aliphatic hydrocarbons remain in the pyrolysis oil, and 2) the reaction temperature is about 600 ° C. to 650 ° C. When the level changes, the aromatization reaction of long-chain aliphatic hydrocarbons proceeds rapidly, and the long-chain aliphatic hydrocarbons change to aromatic hydrocarbons corresponding to A heavy oil with aliphatic side chains. The long-chain aliphatic hydrocarbons disappear and the low-temperature viscosity is improved. 3) When the reaction temperature is changed from about 650 ° C. to about 700 ° C., condensation polycyclic aromatic hydrocarbons (high molecular weight) ) Progresses rapidly, and the low-temperature viscosity accompanying the increase in the molecular weight of aromatic hydrocarbons Was found that the increase in results.

The present invention has been proposed in order to solve such problems, and the gist thereof is as shown in the following (1) to (8).
(1) The first invention is a pyrolysis process in which waste plastic is pyrolyzed to generate pyrolysis gas, and the generated pyrolysis gas is cooled to condense oily components in the pyrolysis gas, thereby pyrolyzing. In a method for pyrolyzing waste plastic having a pyrolysis oil production step for producing oil, a reaction temperature of the pyrolysis step is set to 650 ° C. ± 20 ° C., and the pyrolysis oil produced in the pyrolysis oil production step is recovered This is a method for thermally decomposing waste plastics.
(2) The second invention is characterized in that, in the first invention, the recovered pyrolysis oil is recovered so that the flash point is 60 ° C. or higher.
(3) The third invention is characterized in that, in the first invention, the recovered pyrolysis oil is recovered so as to become a third petroleum at a flash point of 70 ° C. or higher.
(4) A fourth invention is the method according to any one of (1) to (3), wherein the thermal decomposition step is an external heat rotary kiln, and the reaction temperature of the thermal decomposition step is the external heat. It is controlled by the inner cylinder temperature of the rotary kiln.
(5) A fifth invention is a method according to any one of (1) to (4), wherein the light oil liquefied at room temperature contained in the pyrolysis gas after the pyrolysis oil production step. A light oil separation step for separating the components and a gas purification step for purifying the pyrolysis gas after the light oil separation are provided, and the pyrolysis gas after the gas purification step is recovered.
(6) The sixth invention is the method described in any one of (1) to (5) above, wherein the waste plastic is “other plastic container packaging” defined by the Containers and Packaging Recycling Law. It is characterized by.
(7) The seventh invention is a pyrolysis furnace capable of adjusting the reaction temperature to 650 ° C. ± 20 ° C. for generating pyrolysis gas by pyrolyzing waste plastic, and cooling the generated pyrolysis gas to heat A pyrolysis oil generator that generates a pyrolysis oil by condensing an oil component having a flash point of 60 ° C. or higher or a flash point of 70 ° C. or more contained in the cracked gas, and cooling the pyrolysis gas after the pyrolysis oil generator Waste plastics comprising: a light oil separation device that separates light oil components liquefied at room temperature contained in pyrolysis gas; and a gas purification device that purifies the pyrolysis gas after separation of light oil Is a thermal decomposition apparatus.
(8) The eighth invention is characterized in that, in the apparatus according to (7), the pyrolysis furnace is an external heat rotary kiln type pyrolysis furnace capable of adjusting an inner cylinder temperature to 650 ° C. ± 20 ° C. And

According to the present invention, oil that can be transported even at a low temperature of 0 ° C. corresponding to A heavy oil or third petroleum, which has a higher utility value than conventional waste plastic oil conversion methods and waste plastic gasification methods, is recovered from waste plastics. Is possible.
Furthermore, according to another aspect of the present invention, the present invention makes it possible to recover high calorie gas that can replace LNG from waste plastic.

  FIG. 1 is a block diagram showing an example of the equipment configuration for carrying out the waste plastic thermal decomposition method and thermal decomposition apparatus of the present invention according to the first embodiment. Waste plastic 1 is quantitatively supplied into a pyrolysis furnace 3 whose reaction temperature is adjusted to 650 ° C. ± 20 ° C. using a waste feeder 2 such as a screw feeder, and the waste plastic 1 is pyrolyzed in the pyrolysis furnace 3. By processing, a pyrolysis gas 4 and a pyrolysis residue 5 composed of a combustible gas and an oil component are generated.

The pyrolysis gas 4 generated in the pyrolysis furnace 3 is introduced into a pyrolysis oil generator 6 provided at the rear stage of the pyrolysis furnace 3 and cooled, and the flash point contained in the pyrolysis gas 4 is 60 ° C. or higher. By condensing oily components, a pyrolysis oil 7 having a low viscosity with a kinematic viscosity of several hundred mm ² / s level (several hundred cSt level) even at a liquid temperature of 0 ° C. and having properties equivalent to heavy oil A is produced. Can do. Here, the pyrolysis oil having properties equivalent to A heavy oil is a heat having a kinematic viscosity of 20 mm ² / s or less (20 cSt or less) at a liquid temperature of 50 ° C. prescribed by JIS standard JIS-K2205 and a flash point of 60 ° C. or more. Indicates cracked oil.

Further, by making the oily component condensed in the pyrolysis oil generator 6 a component having a flash point of 70 ° C. or higher, the liquid temperature is 0 ° C., and the viscosity is several hundred mm ² / s level (several hundred cSt level). In addition, it is possible to obtain a pyrolysis oil 7 having a kinematic viscosity equivalent to heavy oil A (kinematic viscosity at a liquid temperature of 50 ° C. of 20 mm ² / s or less) and having a higher industrial value, similar to third petroleums.

  As a method for adjusting the oil component condensed in the pyrolysis oil generator 6 to a flash point of 60 ° C. or higher or a flash point of 70 ° C. or higher, for example, the fact that the flash point and boiling point are usually in a primary correlation relationship is used. The relationship between the flash point of the recovered oil and the boiling point is measured and grasped in advance, and the pyrolysis gas cooling temperature of the pyrolysis oil generator is adjusted so that only components above the specified boiling point are condensed and recovered. It is possible to apply this method.

When the reaction temperature of the pyrolysis furnace 3 is outside the range of the present invention, the low temperature kinematic viscosity of the pyrolysis oil 7 produced by the pyrolysis oil production device 6 is 1000 mm ² / s or more (1000 cSt or more ) Is not preferable. That is, when the reaction temperature of the pyrolysis furnace 3 falls below 630 ° C., long-chain aliphatic hydrocarbons remain in the generated pyrolysis oil, and the 0 ° C. kinematic viscosity rises to 1000 mm ² / s or more (1000 cSt or more). On the other hand, when the reaction temperature exceeds 670 ° C., the pyrolysis oil is condensed polycyclic (high molecular weight), and the 0 ° C. kinematic viscosity rapidly increases to 2000 mm ² / s or more (2000 cSt or more).

  Regarding the reaction time of the pyrolysis gas in the pyrolysis furnace 3, if it is too short, the aromatization reaction of long-chain aliphatic hydrocarbons does not proceed sufficiently, leading to destabilization of the quality of the pyrolysis oil. For example, it is preferable to secure a sufficient time such as a reaction time of about 20 seconds or more.

  The method of the pyrolysis furnace 3 is not particularly limited, and general pyrolysis furnace methods such as a moving bed method and an external heat rotary kiln method are applicable. In addition, when pyrolytic treatment is performed using waste plastic with a small amount of pyrolysis residue as a raw material, if the waste plastic melts and softens easily in the pyrolysis furnace, a lump is likely to occur. It is preferable that an additive having a non-volatile component such as a carbide or an inorganic compound is charged into a pyrolysis furnace together with waste plastic. As the aforementioned additive, a part of the pyrolysis residue 5 generated from the pyrolysis furnace 3 may be used.

  The reaction temperature of the pyrolysis furnace 3 is usually the pyrolysis gas temperature in the furnace, and the pyrolysis gas temperature is measured by a thermocouple charged in the furnace. In the second embodiment, the method of the pyrolysis furnace 3 is used. When an external heat rotary kiln is used, the reaction temperature is the inner cylinder temperature of the external heat rotary kiln. When the present inventors pyrolyze waste plastic with a rotary kiln, the pyrolysis gas further receives a thermal history in the vicinity of the kiln inner cylinder, which is higher in temperature than the gas temperature in the furnace, and causes a secondary reaction. It has been found that the properties of the pyrolysis oil recovered by the pyrolysis oil generator 6 is governed by the degree of secondary reaction of pyrolysis gas in the vicinity of the kiln inner cylinder, and the reaction temperature is set to the inner cylinder of the kiln. It came to invention of this method made into temperature. The kiln inner cylinder temperature is measured, for example, by measuring the outer surface temperature of the kiln inner cylinder with a thermocouple and calculating the inner surface temperature of the kiln inner cylinder by actually measuring the inner surface temperature during heat transfer calculation or trial operation. The method of doing etc. can be considered.

  Therefore, the rotary kiln may be a rotary kiln having a control function capable of adjusting the inner surface temperature of the kiln inner cylinder to 650 ° C. ± 20 ° C.

  The method of the pyrolysis oil generator 6 is not particularly limited. In addition to the indirect cooling method in which the pyrolysis gas is brought into contact with a double pipe or the like in which a cooling medium is passed, the generated pyrolysis oil 7 is cooled with pyrolysis gas. A direct cooling method in which the cooled pyrolysis oil is used as a medium and counter-contacted with the pyrolysis gas is applicable.

The pyrolysis gas (gas after pyrolysis oil separation) 8 after the pyrolysis oil generator is further cooled by the light oil separator 9 in the next step and liquefied at room temperature including BTX (benzene, toluene, xylene). The light oil 10 to be condensed is separated, and the pyrolysis gas (gas after light oil separation) 11 after separation of the light oil is removed by a gas purification device 12 similar to the gas purification technology of the prior art, and gas purification such as dust removal and dehydrochlorination is performed. After the treatment, the product gas 13 is recovered. The product gas 13 is a high-calorie gas having a low calorific value around 10000 kcal / Nm ³ (around 42000 kJ / Nm ³ ) mainly composed of hydrocarbons having 1 to 3 carbon atoms and hydrogen, and can be used as an LNG alternative gas. is there.

Therefore, in the present invention, the recovered oil becomes oil corresponding to heavy oil A or third petroleum, and a complicated refining process is unnecessary, and the product gas can be refined by a conventional gas refining technique.
The light oil 10 separated by the light oil separator 9 is a high calorie oil having a low calorific value of around 10,000 kcal / kg (around 42000 kJ / kg), and can be used as a fuel oil for heating the pyrolysis furnace 3, It can be effectively used as a fuel source for electric power and steam production facilities.
In addition, since any plastic containing polyethylene has the pyrolysis oil generation behavior of the following 1) to 3), the types of waste plastic applicable in the present invention are not limited to the volumetric plastics and industrial waste containing polyethylene. It can also be applied to plastic.
1) Until the reaction temperature reaches about 600 ° C., undecomposed long-chain aliphatic hydrocarbons that inhibit low-temperature viscosity remain in the pyrolysis oil, and a small amount of long-chain aliphatic hydrocarbons remain in the pyrolysis oil. Also low temperature viscosity is hindered.
2) When the reaction temperature is changed from about 600 ° C. to about 650 ° C., the aromatization reaction of long chain aliphatic hydrocarbons proceeds rapidly, and the long chain aliphatic hydrocarbons have aliphatic side chains. Changes to aromatic hydrocarbons equivalent to heavy oil, and long-chain aliphatic hydrocarbons disappear and low-temperature viscosity improves.
3) When the reaction temperature is changed from about 650 ° C. to about 700 ° C., the condensation polycyclization (high molecular weight) of aromatic hydrocarbons proceeds rapidly, and the low temperature viscosity accompanying the increase in the molecular weight of aromatic hydrocarbons. Rises.

The example which processed the capacity | capacitance repura with the process scale of 200 t / day using the installation structure shown in FIG. 1 mentioned above is shown. The pyrolysis furnace 3 uses an externally heated rotary kiln equipped with a hot air generator that uses the generated light oil as a fuel, and the pyrolysis oil generator 6 brings the pyrolysis gas into contact with the cooling medium in a countercurrent to remove oily components. Using a direct heat exchange system that condenses as pyrolysis oil and uses the generated pyrolysis oil as a cooling medium for the pyrolysis gas, the light oil separation device 9 makes the pyrolysis gas contact the multiple pipes that flowed the cooling water. The indirect heat exchange system for cooling was used, and the gas purification apparatus 12 used a wet gas cleaning tower system. A pyrolysis furnace 3 having a reaction temperature adjusted to a range of 650 ° C. ± 20 ° C. (630 ° C. to 670 ° C.) is charged with a volumetric reactor to produce pyrolysis gas 4 and pyrolysis residue 5. It introduced into the pyrolysis oil production | generation apparatus 6, it cooled, and pyrolysis oil 7 was obtained about 30 m < ³ > / day. The reaction temperature is the inner surface temperature of the kiln inner cylinder, and as a method for adjusting the reaction temperature, the relationship between the temperature difference between the inner surface temperature and the outer surface temperature of the kiln inner cylinder is measured and grasped in advance. The thermocouple temperature inserted on the outer surface of the inner cylinder was measured to adjust the outer surface temperature of the kiln inner cylinder. Specifically, since the temperature difference between the outer surface temperature and the inner surface temperature of the kiln inner cylinder was 10 ° C., the outer surface temperature of the kiln inner cylinder was adjusted to be 640 ° C. to 680 ° C.

The produced pyrolysis oil 7 had a kinematic viscosity at a liquid temperature of 0 ° C. of about 300 mm ² / s (about 300 cSt), and was a low-temperature viscosity oil that could be fed even in winter. The pyrolysis oil 7 had a flash point of about 80 ° C. and a 50 ° C. kinematic viscosity of about 10 mm ² / s (about 10 cSt), and was an oil equivalent to A heavy oil similar to the third petroleum. The product gas 13 after the gas purification device has a production amount of about 80,000 Nm ³ / day and a low calorific value of about 12,000 kcal / Nm ³ (about 50000 kJ / Nm ³ ), which is a high calorie gas that can be used as an LNG alternative gas. Obtained.

(Comparative Example 1)
As Comparative Example 1, the reaction temperature of the pyrolysis furnace 3 is set to a range of 700 ± 20 ° C. (680 ° C. to 720 ° C.), the other conditions are the same as those in Example 1, and the same treatment is applied to the same volume of repulsor as in Example 1. Processed at a volume of 200 t / day. The obtained pyrolysis oil had a kinematic viscosity at a liquid temperature of 0 ° C. of about 2300 mm ² / s (about 2300 cSt), and it was not possible to produce a pyrolysis oil having a low low temperature viscosity, which is a problem of the prior art. Further, the kinematic viscosity at 50 ° C. was about 30 mm ² / s (about 30 cSt), the flash point was 80 ° C., and the oil property equivalent to heavy oil A was not achieved.

(Comparative Example 2)
As Comparative Example 2, the reaction temperature of the pyrolysis furnace 3 is set to a range of 600 ° C. ± 20 ° C. (580 ° C. to 620 ° C.), the other conditions are the same as those of Example 1, and the same volume of the same size as in Example 1 is used. Processing was performed at a throughput of 200 t / day. The obtained pyrolysis oil was an oil having a flash point of about 80 ° C., a 50 ° C. kinematic viscosity of about 10 mm ² / s (about 10 cSt), and a property equivalent to A heavy oil similar to the third petroleum, but at a liquid temperature of 0 ° C. The kinematic viscosity cannot be measured due to solidification of the pyrolysis oil, and it was not possible to produce a pyrolysis oil having a low low temperature viscosity, which is a problem of the prior art.

It is a block diagram which shows the equipment example of the apparatus which concerns on 1st invention of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Waste plastic 2 ... Waste supply apparatus 3 ... Pyrolysis furnace 4 ... Pyrolysis gas 5 ... Pyrolysis residue 6 ... Pyrolysis oil production | generation apparatus 7 ... Pyrolysis Oil 8 ... Gas after pyrolysis oil separation 9 ... Light oil separation device 10 ... Light oil 11 ... Gas oil separation gas 12 ... Gas purification device 13 ... Product gas

Claims (8)

  A pyrolysis process for pyrolyzing waste plastic containing polyethylene to generate pyrolysis gas, and heat for generating pyrolysis oil by cooling the generated pyrolysis gas and condensing oily components in the pyrolysis gas In the method for pyrolyzing waste plastic having a cracked oil production step, the reaction temperature of the pyrolysis step is set to 650 ° C. ± 20 ° C., and the pyrolysis oil produced in the pyrolysis oil production step is recovered. Thermal decomposition method of waste plastic.   2. The method for pyrolyzing waste plastic according to claim 1, wherein the recovered pyrolysis oil is recovered so that a flash point is 60 ° C. or higher.   2. The method for pyrolyzing waste plastic according to claim 1, wherein the recovered pyrolysis oil is recovered so as to become a third petroleum at a flash point of 70 ° C. or higher.   The heat of waste plastic according to any one of claims 1 to 3, wherein the thermal decomposition process is an external heat rotary kiln, and the reaction temperature of the thermal decomposition process is controlled by the inner cylinder temperature of the external heat rotary kiln. Disassembly method.   A light oil separation step for separating light oil components that are liquefied at room temperature contained in the pyrolysis gas and a gas purification step for purifying the pyrolysis gas after separation of the light oil are provided after the pyrolysis oil generation step, The method for pyrolyzing waste plastics according to any one of claims 1 to 4, wherein the pyrolysis gas after the gas purification step is recovered.   The waste plastic thermal decomposition method according to claim 1, wherein the waste plastic is “other plastic container packaging” defined by the Containers and Packaging Recycling Law.   A pyrolysis furnace that can be adjusted to a reaction temperature of 650 ° C. ± 20 ° C. for generating a pyrolysis gas by pyrolyzing waste plastic, and a flash point 60 contained in the pyrolysis gas by cooling the generated pyrolysis gas. A pyrolysis oil generator for condensing an oily component having a flash point of 70 ° C. or higher or a flash point of 70 ° C. or higher, and a pyrolysis gas after the pyrolysis oil generator is cooled to be contained in the pyrolysis gas. A waste plastic pyrolysis apparatus comprising a light oil separation apparatus that separates light oil components that are liquefied at room temperature and a gas purification apparatus that purifies the pyrolysis gas after separation of the light oil.   8. The waste plastic pyrolysis apparatus according to claim 7, wherein the pyrolysis furnace is an external heat rotary kiln type pyrolysis furnace capable of adjusting an inner cylinder temperature to 650 ° C. ± 20 ° C.

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