Method for producing pyrolysis oil, method for producing elastomer, method for producing rubber product, and method for producing resin product

Abstract

The present invention addresses the problem of providing a method for producing a pyrolysis oil which is a light oil and is rich in olefins. This method for producing a pyrolysis oil is characterized by comprising a step in which a waste material including used tires is pyrolyzed in a pyrolysis furnace to obtain a pyrolysis gas and a solid including a carbide, and a step in which the pyrolysis gas is cooled to obtain a pyrolysis oil, wherein the pyrolysis temperature is 300-500°C and the pyrolysis reaction time is 0.6 minutes or longer.

Description

Methods for producing pyrolysis oil, methods for producing elastomers, methods for producing rubber products, and methods for producing resin products

[0001] The present invention relates to a method for producing pyrolysis oil, a method for producing an elastomer, a method for producing a rubber product, and a method for producing a resin product.

[0002] Recently, recycling of used rubber products, including used tires, has been promoted from the viewpoint of protecting the global environment. One such recycling method is a technique of pyrolyzing used rubber products and recovering pyrolysis products such as oil (pyrolysis oil) and carbon black (carbide). For example, Patent Document 1 listed below discloses a method of recovering carbon and hydrocarbon mixtures from waste tires or similar polymer materials by pyrolysis.

[0003] Special Publication No. 2002-523552

[0004] As described in Patent Document 1 and elsewhere, various studies have been conducted on methods for pyrolyzing used tires, but no studies have been conducted on the components in the pyrolysis oil recovered by pyrolysis. Meanwhile, in order to pyrolyze used tires and reuse them as a raw material for chemical products, it is preferable that the recovered pyrolysis oil is light (i.e., has a relatively small molecular weight) and also contains a large amount of olefins (i.e., components having non-aromatic carbon-carbon double bonds) so that it can be easily converted into various chemical products.

[0005] Therefore, an object of the present invention is to provide a method for producing a light pyrolysis oil that is rich in olefins.A further object of the present invention is to provide methods for producing elastomers, rubber products, and resin products using the pyrolysis oil obtained by the method for producing pyrolysis oil.

[0006] The gist of the present invention, which solves the above-mentioned problems, is as follows: a method for producing pyrolysis oil, a method for producing an elastomer, a method for producing a rubber product, and a method for producing a resin product.

[0007] [1] A method for producing pyrolysis oil, comprising: a step of pyrolyzing waste materials including used tires in a pyrolysis furnace to obtain a solid material including a pyrolysis gas and a char; and a step of cooling the pyrolysis gas to obtain a pyrolysis oil, wherein the pyrolysis temperature is 300°C to 500°C, and the pyrolysis reaction time is 0.6 minutes or longer.

[0008] [2] The method for producing pyrolysis oil according to [1], wherein 55 mass% or more of the pyrolysis gas is recovered as pyrolysis oil.

[0009] [3] The method for producing a pyrolysis oil according to [1] or [2], which does not include a step of further fractionating the pyrolysis oil obtained after cooling the pyrolysis gas.

[0010] [4] The method for producing pyrolysis oil according to any one of [1] to [3], wherein the carbonized material contains carbon black.

[0011] [5] The method for producing pyrolysis oil according to any one of [1] to [4], wherein the yield of the pyrolysis oil is 30% or more based on the mass of the waste material.

[0012] [6] The method for producing pyrolysis oil according to any one of [1] to [5], wherein the pyrolysis is carried out in an atmosphere of gas generated by pyrolysis.

[0013] [7] The method for producing a pyrolysis oil according to any one of [1] to [6], wherein the pyrolysis is carried out under an atmosphere of a mixture of an inert gas and a gas generated by pyrolysis.

[0014] [8] The method for producing pyrolysis oil according to any one of [1] to [7], wherein the pressure inside the pyrolysis furnace is 0.1 kPaG or less.

[0015] [9] The method for producing pyrolysis oil according to any one of [1] to [8], wherein the pressure inside the pyrolysis furnace is 0 kPaG or less.

[0016]

[10] A method for producing an elastomer, in which the pyrolysis oil obtained by the production method according to any one of [1] to [9] is used as at least a part of the raw material of the elastomer.

[0017]

[11] The method for producing an elastomer according to

[10] , wherein the elastomer is at least one selected from the group consisting of resins and synthetic rubbers.

[0018]

[12] A method for producing a rubber product, comprising a vulcanization step of using the synthetic rubber obtained by the production method according to

[11] as at least a part of the raw materials for the rubber product, and obtaining the rubber product by a vulcanization reaction.

[0019]

[13] The method for producing a rubber product according to

[12] , wherein the rubber product is at least one selected from the group consisting of a rubber tire, a rubber crawler, a rubber hose, a conveyor belt, and a seismic isolation rubber.

[0020]

[14] A method for producing a resin product, using the resin obtained by the production method according to

[11] as at least a part of the raw material of the resin product.

[0021]

[15] The method for producing a resin product according to

[14] , wherein the resin product is at least one selected from the group consisting of a resin tire and a resin hose.

[0022] The present invention provides a method for producing a light pyrolysis oil that is rich in olefins, and also provides methods for producing elastomers, rubber products, and resin products using the pyrolysis oil obtained by the method.

[0023] FIG. 1 is a diagram illustrating classification of compounds in the pyrolysis oil recovered in the examples and comparative examples according to their structures.

[0024] Hereinafter, the method for producing pyrolysis oil, the method for producing elastomer, the method for producing rubber products, and the method for producing resin products of the present invention will be described in detail with reference to examples based on their embodiments.

[0025] <Definitions> The compounds described herein may be derived in whole or in part from fossil resources, from biological resources such as plant resources, from recycled resources such as used tires, or from a mixture of two or more of fossil resources, biological resources, and recycled resources.

[0026] <Method for Producing Pyrolysis Oil> The method for producing pyrolysis oil of this embodiment includes the steps of pyrolyzing waste materials, including used tires, in a pyrolysis furnace to obtain a solid material containing pyrolysis gas and char, and cooling the pyrolysis gas to obtain pyrolysis oil. The method for producing pyrolysis oil of this embodiment is characterized in that the pyrolysis temperature is 300°C to 500°C and the pyrolysis reaction time is 0.6 minutes or longer. Here, the pyrolysis reaction time refers to the time from when the furnace temperature reaches the reaction temperature to when the furnace gas is released in the case of a closed pyrolysis furnace, and refers to a value calculated based on the following formula in the case of an open or continuous pyrolysis furnace.

[0027] In the method for producing pyrolysis oil of this embodiment, the pyrolysis temperature is 300°C or higher and the pyrolysis reaction time is 0.6 minutes or longer, thereby allowing the pyrolysis of waste materials including used tires to proceed sufficiently. Furthermore, in the method for producing pyrolysis oil of this embodiment, the pyrolysis temperature is 500°C or lower, thereby suppressing the aromatization of the pyrolysis gas, and by cooling the resulting pyrolysis gas, a light pyrolysis oil rich in olefins can be obtained. Therefore, according to the method for producing pyrolysis oil of this embodiment, a light pyrolysis oil rich in olefins can be efficiently obtained.

[0028] (Pyrolysis Step) The method for producing pyrolysis oil of this embodiment includes a step of pyrolyzing waste materials including used tires in a pyrolysis furnace to obtain a solid material including pyrolysis gas and char. By pyrolyzing waste materials including used tires to obtain a solid material including pyrolysis gas and char, and then cooling the solid material to obtain a light pyrolysis oil rich in olefins, the waste materials including used tires can be effectively utilized as a resource. Therefore, the method for producing pyrolysis oil of this embodiment can contribute to the recycling of waste materials including used tires. Note that in the pyrolysis step, parts and components of the waste materials that do not become pyrolysis gas remain in the pyrolysis furnace as residue. Examples of the residue include char, such as carbon black. Carbon black is in high demand, so recovering carbon black as a char can further contribute to promoting the recycling of waste materials including used tires.

[0029] -Raw Materials- The waste materials used as raw materials for the pyrolysis include used tires. The used tires may be grouped in advance by tire type (e.g., for passenger cars, trucks, buses, large vehicles such as off-road vehicles, aircraft, agricultural vehicles, etc.), and then pyrolysis may be carried out for each group. Alternatively, the used tires may be grouped in advance by tire component (e.g., tread rubber, sidewall rubber, bead rubber, steel cord-coated rubber, organic fiber-coated rubber, pad rubber, cushion rubber, etc.), and then pyrolysis may be carried out for each group. Furthermore, the used tires may be grouped both by tire type and by tire component, and then pyrolysis may be carried out for each group. When pyrolysis is carried out for each group in this way, pyrolysis oil with more uniform physical properties is obtained.

[0030] The used tires may contain metal reinforcing materials such as steel cords and bead cores. When the used tires contain metal reinforcing materials, the metal reinforcing materials may or may not be removed from the used tires in advance. When the metal reinforcing materials are not removed from the used tires, the metal reinforcing materials remain as residue in the pyrolysis furnace. The used tires may also be cut and crushed in advance. Here, the method for removing the metal reinforcing materials from the used tires or their crushed materials is not particularly limited, and examples include methods using magnets, sieves, etc. The used tires may also contain organic fiber reinforcing materials such as organic fiber cords. When the used tires contain organic fiber reinforcing materials, the organic fiber reinforcing materials may or may not be removed from the used tires in advance. When the organic fiber reinforcing materials are not removed from the used tires, the organic fiber reinforcing materials remain as residue in the pyrolysis furnace or are vaporized and discharged as gas. The used tires may be cut and crushed in advance. The method for removing the organic fiber reinforcing material and the like from the used tires or their crushed products is not particularly limited, and examples thereof include methods using centrifugal force, sieving, etc. The method for crushing the used tires is also not particularly limited, and examples thereof include mechanical crushing using a single-shaft crusher or a twin-shaft crusher, crushing using a water jet, freeze crushing, laser crushing, etc.

[0031] The waste material may include waste materials other than used tires, such as waste rubber products other than tires, waste plastics, and the like.

[0032] The used tires and other rubber product waste (waste rubber) other than tires typically contain diene rubber as a rubber component, and further contain compounding agents such as fillers such as carbon black, silica, and calcium carbonate, silane coupling agents, antioxidants, softeners, processing aids, resins, surfactants, organic acids (stearic acid, etc.), zinc oxide (zinc white), vulcanization accelerators, and crosslinking agents (sulfur, peroxides, etc.). Specific examples of the diene rubber include natural rubber (NR), synthetic isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), and chloroprene rubber (CR). According to the method for producing pyrolysis oil of this embodiment, the above-mentioned light pyrolysis oil rich in olefins can be obtained by primarily subjecting these rubber components to pyrolysis.

[0033] - Pyrolysis Temperature - In the method for producing pyrolysis oil of this embodiment, the pyrolysis temperature is 300°C to 500°C. By setting the pyrolysis temperature to 300°C or higher, it is possible to promote the pyrolysis of waste materials including used tires. Furthermore, by setting the pyrolysis temperature to 500°C or lower, it is possible to suppress aromatization of the pyrolysis gas produced, thereby making it possible to obtain a light pyrolysis oil that is rich in olefins. From the viewpoint of promoting the pyrolysis of waste materials, the pyrolysis temperature is preferably 350°C or higher, and from the viewpoint of suppressing aromatization of the pyrolysis gas produced, the pyrolysis temperature is preferably 450°C or lower.

[0034] The method for controlling the pyrolysis temperature is not particularly limited, and may be, for example, a method in which a heating means is attached to the pyrolysis furnace and the temperature of the pyrolysis furnace is increased by the heating means, a method in which the pyrolysis furnace is introduced into an electric furnace heated to a predetermined temperature, a method in which high-temperature gas heated to a predetermined temperature is introduced into the pyrolysis furnace, or other methods.

[0035] - Pyrolysis Furnace - The pyrolysis furnace is not particularly limited, and examples thereof include a batch pyrolysis furnace, a fluidized bed pyrolysis furnace, and a kiln pyrolysis furnace. In one embodiment, the pyrolysis furnace comprises an inlet flow path for introducing an inert gas and an outlet flow path for discharging the inert gas and the generated pyrolysis gas. Furthermore, a flow rate adjusting device is preferably attached to the inlet flow path, and the amount of inert gas introduced can be adjusted by the flow rate adjusting device. The flow rate adjusting device attached to the inlet flow path is not particularly limited, and examples thereof include a mass flow controller. Furthermore, a flow rate adjusting device is preferably attached to the outlet flow path, and the amount of discharged mixed gas of the inert gas and the generated pyrolysis gas can be adjusted by the flow rate adjusting device. The flow rate adjusting device attached to the outlet flow path is not particularly limited, and examples thereof include an exhaust pressure valve. Note that a flow rate adjusting device attached to the inlet flow path makes it easier to control the residence time of the pyrolysis gas in the pyrolysis furnace and the pyrolysis reaction time than a flow rate adjusting device attached to the outlet flow path.

[0036] -Reaction Time- In the method for producing pyrolysis oil of this embodiment, the pyrolysis reaction time is 0.6 minutes or more. A pyrolysis reaction time of 0.6 minutes or more allows the pyrolysis of waste materials including used tires to proceed sufficiently. From the viewpoint of further advancing the pyrolysis of the waste materials, the pyrolysis reaction time is preferably 1.0 minute or more. Furthermore, the pyrolysis reaction time is preferably 10.0 minutes or less. If the pyrolysis reaction time exceeds 10.0 minutes, the pyrolysis gas will be turned into off-gas, the yield of pyrolysis oil will decrease, and the aromatization of the pyrolysis gas will increase, resulting in a decrease in the yield of light pyrolysis oil rich in olefins.

[0037] Atmosphere: In the method for producing pyrolysis oil according to this embodiment, the pyrolysis is preferably carried out in an atmosphere of a mixture of the gas generated by pyrolysis and an inert gas, or in the atmosphere of the gas generated by pyrolysis. By carrying out the pyrolysis in an atmosphere of a mixture of the gas generated by pyrolysis and an inert gas, or in the atmosphere of the gas generated by pyrolysis, oxidation of the waste raw material and the generated pyrolysis gas is suppressed, resulting in a pyrolysis gas containing a higher olefin content. After the cooling step described below, a pyrolysis oil containing a higher olefin content can be obtained. Examples of inert gases include nitrogen, carbon dioxide, argon, and helium. The atmosphere of the mixture of the gas generated by pyrolysis and an inert gas, or the atmosphere of the gas generated by pyrolysis, may contain 1% or less by volume of oxygen.

[0038] In the method for producing pyrolysis oil of this embodiment, it is preferable to carry out the pyrolysis while circulating a mixture of gas generated by pyrolysis and an inert gas, or the gas generated by pyrolysis, in the pyrolysis furnace. By carrying out the pyrolysis while circulating a mixture of gas generated by pyrolysis and an inert gas, or the gas generated by pyrolysis, in the pyrolysis furnace, oxidation of the raw material waste and the generated pyrolysis gas is suppressed, and a pyrolysis gas containing a higher olefin content is obtained. In addition, by adjusting the flow rate of the inert gas, it is easy to accurately control the residence time of the pyrolysis gas in the pyrolysis furnace, i.e., the pyrolysis reaction time. By undergoing the cooling process described below, a light pyrolysis oil containing a higher olefin content can be obtained.

[0039] -Other- The thermal decomposition step can be carried out at any pressure, whether under reduced pressure, normal pressure, or elevated pressure. By carrying out the thermal decomposition under reduced pressure or normal pressure, polymerization (repolymerization) of olefins in the thermal decomposition gas can be suppressed.

[0040] In the method for producing pyrolysis oil of this embodiment, the pressure in the pyrolysis furnace is preferably 0.1 kPaG or less, more preferably 0 kPaG or less, in gauge pressure. When the pressure in the pyrolysis furnace is 0.1 kPaG or less, polymerization (repolymerization) of olefins in the pyrolysis gas can be further suppressed, and when the pressure in the pyrolysis furnace is 0 kPaG or less, polymerization (repolymerization) of olefins in the pyrolysis gas can be further suppressed. When the pressure in the pyrolysis furnace is 0 kPaG or less, a reduced pressure state is also included.

[0041] The thermal decomposition step may or may not use a catalyst, but it is preferable not to use a catalyst. Not using a catalyst in the thermal decomposition step can reduce the cost of the thermal decomposition step. When a catalyst is used, any catalyst that has the effect of accelerating the thermal decomposition reaction of waste materials including used tires can be used, and examples of such catalysts include acidic catalysts such as zeolite, activated clay, acid clay, and bentonite, and basic catalysts such as sodium carbonate.

[0042] (Cooling Step) The method for producing pyrolysis oil according to this embodiment includes a step of cooling the pyrolysis gas to obtain pyrolysis oil. By cooling the pyrolysis gas, the pyrolysis gas is separated into gaseous off-gas and liquefied pyrolysis oil, thereby obtaining the target product, light pyrolysis oil rich in olefins. The components of the off-gas depend on the cooling temperature, but examples include gaseous components at atmospheric pressure and 20°C, such as hydrogen and hydrocarbons with 1 to 4 carbon atoms. The off-gas can be used as a raw material for chemical products or as a fuel for the heat source of a pyrolysis furnace.

[0043] The method for cooling the pyrolysis gas is not particularly limited, and the pyrolysis gas may be actively cooled using a condenser, a cooling tower, or the like, or may be naturally cooled by standing to cool. The cooling temperature of the pyrolysis gas is also not particularly limited, and is preferably, for example, −20° C. to 100° C., and more preferably 0° C. to 50° C. When the pyrolysis gas is cooled using a medium, the medium is not particularly limited, and examples thereof include water.

[0044] In the method for producing pyrolysis oil of this embodiment, the yield of the pyrolysis oil is preferably 30% or more, more preferably 35% or more, based on the mass of the waste material. When the yield of the pyrolysis oil is 30% or more, based on the mass of the waste material, a large amount of light pyrolysis oil rich in olefins can be efficiently obtained, improving economic efficiency and further contributing to the recycling of waste materials including used tires.

[0045] In the method for producing pyrolysis oil of this embodiment, it is preferable that 55 mass% or more of the pyrolysis gas is recovered as pyrolysis oil. By recovering 55 mass% or more of the pyrolysis gas as pyrolysis oil, a large amount of light pyrolysis oil rich in olefins can be efficiently obtained, which improves economic efficiency and further contributes to the recycling of waste materials including used tires.

[0046] (Other Steps) The method for producing pyrolysis oil of this embodiment may include other steps in addition to the pyrolysis step and cooling step described above. Examples of other steps include a pretreatment step for the raw material waste, a char processing step for processing the char to obtain carbon black, and a purification step for the produced pyrolysis oil. The char processing step may include steps such as a step for removing substances other than carbon black, a pulverization step, and a carbon black granulation step. The method for the char processing step is not particularly limited, and generally known processing methods can be used. However, the method for producing pyrolysis oil of this embodiment preferably does not include a step for further fractionating the pyrolysis oil obtained in the cooling step. By not including a step for fractionating the pyrolysis oil obtained after cooling the pyrolysis gas, the pyrolysis oil yield based on the mass of the rubber component in the raw material waste is improved, and the overall process is simplified, improving economic efficiency.

[0047] <Pyrolysis Oil> The pyrolysis oil obtained by the pyrolysis oil production method of the present embodiment described above is light and rich in olefins. The fact that the pyrolysis oil is light means that the pyrolysis oil contains many components with relatively small molecular weights. These relatively small molecular weight components can be easily used as chemical products as they are, and can also be easily converted into other chemical products by additional processing or reaction. Furthermore, when the pyrolysis oil contains butadiene, isoprene, or the like as relatively small molecular weight components, these components can be used as raw materials for rubber (especially diene rubber).

[0048] (T90) The pyrolysis oil preferably has a 90% (mass) distillation temperature (T90) of 400°C or less, more preferably 350°C or less. When the 90% distillation temperature of the pyrolysis oil is 400°C or less, the pyrolysis oil becomes even lighter, making it easier to use as a raw material for chemical products. The lower limit of the 90% distillation temperature of the pyrolysis oil is not particularly limited, but the 90% distillation temperature of the pyrolysis oil obtained by the above-mentioned method is usually 250°C or higher. Herein, the 90% distillation temperature of the pyrolysis oil is a value measured in accordance with ASTM D7169 using a distillation gas chromatograph (GC).

[0049] (T10) The pyrolysis oil preferably has a 10% (mass) distillation temperature (T10) of 100°C or higher, more preferably 110°C or higher. Pyrolysis oils with a 10% distillation temperature of 100°C or higher contain fewer components with too small a molecular weight, making them easier to use as raw materials for chemical products. The upper limit of the 10% distillation temperature of the pyrolysis oil is not particularly limited, but the 10% distillation temperature of the pyrolysis oil obtained by the above-mentioned method is usually 200°C or lower. Herein, the 10% distillation temperature of the pyrolysis oil is a value measured in accordance with ASTM D7169 using a distillation gas chromatograph (GC).

[0050] (Density) The pyrolysis oil has a density of 0.82 to 0.91 g / cm3 measured at 40°C within 3 hours after acquisition. ３ It is preferable that the density is 0.82 g / cm ３The above pyrolysis oil contains few components with too small molecular weight, making it easier to use as a raw material for chemical products. ３ The following pyrolysis oils contain many components with moderately small molecular weights, making them easier to use as raw materials for chemical products. Therefore, the density is 0.82 to 0.91 g / cm ３ From the viewpoint of ease of use as a raw material for chemical products, the density of the pyrolysis oil is 0.84 g / cm ３ More preferably, it is 0.89 g / cm or more. ３ Furthermore, the pyrolysis oil has a density of 0.84 to 0.97 g / cm when measured at 40°C after leaving the obtained pyrolysis oil for 3 days. ３ This is because if the pyrolysis oil is left open to the air for a long period of time, the low boiling point components will volatilize and the density will change. Here, in this specification, the density of the pyrolysis oil is a value measured at 40°C in accordance with ASTM D4052.

[0051] (Olefin Content) The pyrolysis oil preferably has an olefin content (olefin content) of 10% by volume or more, more preferably 30% by volume or more, and even more preferably 35% by volume or more, as measured by GC×GC-MS (two-dimensional gas chromatography mass spectrometry). When the olefin content of the pyrolysis oil is 10% by volume or more, the pyrolysis oil contains a large amount of compounds having non-aromatic carbon-carbon double bonds. These compounds having non-aromatic carbon-carbon double bonds can be easily used as chemical products as they are, and can also be easily converted into other chemical products by additional processing or reaction, making the pyrolysis oil even more usable as a raw material for chemical products. The upper limit of the olefin content of the pyrolysis oil is not particularly limited, but the olefin content of the pyrolysis oil obtained by the above-mentioned method is typically 60% by volume or less. In this specification, olefin refers to a hydrocarbon having one or more carbon-carbon double bonds and no heteroatoms, aromatic rings, or carbon-carbon triple bonds, and may be linear or cyclic. Examples of olefins include butadiene, isoprene, pentene, hexene, cyclopentene, cyclohexene, cyclopentadiene, dicyclopentadiene, and limonene. Among these, butadiene, isoprene, and the like can be used as raw materials for rubber (particularly diene rubber). In addition, in this specification, the olefin content (olefin content) of the pyrolysis oil is a value measured using a GC×GC-MS (two-dimensional gas chromatograph mass spectrometer) by the method described in the examples.

[0052] (Iodine value) The pyrolysis oil has an iodine value of 180 g / L. ２ / 100g or more is preferable, and 200gI ２ It is more preferable that the iodine value is 180 g / 100 g or more. ２ The pyrolysis oil having an iodine value of 100 g / 100 g or more contains a large amount of olefins, and is therefore more easily usable as a raw material for chemical products. The upper limit of the iodine value of the pyrolysis oil is not particularly limited, but the iodine value of the pyrolysis oil obtained by the above method is usually 400 g / 100 g. ２ In this specification, the iodine value of the pyrolysis oil is a value measured in accordance with JIS K0070.

[0053] (Acid value) The pyrolysis oil preferably has an acid value of 5 mg KOH / g or less. When the acid value of the pyrolysis oil is 5 mg KOH / g or less, the pyrolysis oil is easy to process into a raw material for chemical products, and a high-quality raw material for chemical products can be obtained. Furthermore, it is preferable that benzoic acid and its chloride are not present in the pyrolysis oil. If benzoic acid and its chloride are not present in the pyrolysis oil, precipitates are less likely to occur when the pyrolysis oil is processed into a raw material for chemical products, making it easy to process and allowing a high-quality raw material for chemical products to be obtained. Here, in this specification, the acid value of the pyrolysis oil is a value measured in accordance with JIS K2501.

[0054] (Aromatic content) The aromatic content of the pyrolysis oil, as measured by GC x GC-MS (two-dimensional gas chromatography mass spectrometer), is preferably 80% by volume or less, more preferably 60% by volume or less, and even more preferably 40% by volume or less. Having an aromatic content of 80% by volume or less makes it easier to use the pyrolysis oil as a raw material for chemical products other than benzene, toluene, and xylene. The lower limit of the aromatic content of the pyrolysis oil is not particularly limited, but the aromatic content of the pyrolysis oil obtained by the above-mentioned method is typically 10% by volume or more. Herein, the aromatic content (aromatic compound content) of the pyrolysis oil is a value measured using GC x GC-MS (two-dimensional gas chromatography mass spectrometer) by the method described in the Examples.

[0055] (Olefin content / Aromatic content) The pyrolysis oil preferably has a volume ratio of olefin content to aromatic content (olefin content / aromatic content) measured by GC×GC-MS (two-dimensional gas chromatography mass spectrometry) of 0.1 or more, more preferably 0.2 or more, and even more preferably 0.5 or more. Olefins are compounds having non-aromatic carbon-carbon double bonds, and can be easily used as chemical products as they are, and can also be easily converted into other chemical products by additional processing or reaction. On the other hand, as mentioned above, aromatic compounds are chemically stable and therefore difficult to convert into other compounds. Therefore, pyrolysis oil having a volume ratio of olefin content to aromatic content (olefin content / aromatic content) of 0.1 or more contains many compounds having non-aromatic carbon-carbon double bonds that can be easily used as chemical products, and few aromatic compounds that are difficult to use as chemical products, making it even easier to use as a raw material for chemical products. The upper limit of the volume ratio of olefin content to aromatic content (olefin content / aromatic content) is not particularly limited, but the volume ratio (olefin content / aromatic content) of the pyrolysis oil obtained by the above-mentioned method is usually 10 or less.

[0056] (Other Components) The pyrolysis oil may contain paraffins, alkynes, heterocyclic compounds, etc. in addition to the above-mentioned olefins and aromatic compounds, and may further contain nitrogen components, sulfur components, chlorine components, etc.

[0057] <Method for producing elastomer> The method for producing an elastomer of this embodiment is characterized by using the pyrolysis oil obtained by the above-mentioned production method as at least a part of the raw materials for the elastomer. Because the method for producing an elastomer of this embodiment uses the pyrolysis oil obtained by the above-mentioned production method as at least a part of the raw materials for the elastomer, it can contribute to promoting the recycling of waste materials including used tires.

[0058] The elastomer is preferably at least one selected from the group consisting of resins and synthetic rubbers. Elastomers selected from the group consisting of resins and synthetic rubbers are easy to use in rubber products and resin products, and are in high demand. Therefore, using pyrolysis oil obtained by the above-mentioned production method as at least a part of the raw material for an elastomer selected from the group consisting of resins and synthetic rubbers can further contribute to promoting the recycling of waste materials, including used tires. Examples of resins include thermoplastic elastomers such as polyester-based thermoplastic elastomers (TPC), polyamide-based thermoplastic elastomers (TPA), polyolefin-based thermoplastic elastomers (TPO), and polystyrene-based thermoplastic elastomers (TPS). Examples of synthetic rubbers include diene-based rubbers such as synthetic isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), and chloroprene rubber (CR).

[0059] <Method for Manufacturing Rubber Product> The method for manufacturing a rubber product according to this embodiment is characterized by including a vulcanization step in which a rubber product is obtained by a vulcanization reaction using synthetic rubber obtained by the above-described manufacturing method as at least a portion of the raw materials for the rubber product. Because the method for manufacturing a rubber product according to this embodiment uses synthetic rubber obtained by the above-described manufacturing method as at least a portion of the raw materials for the rubber product, it can contribute to promoting the recycling of waste materials, including used tires. Here, the rubber product can be manufactured, for example, by preparing a rubber composition containing synthetic rubber and a vulcanizing agent such as sulfur in advance, molding the rubber composition into a desired shape, and then subjecting the composition to a vulcanization step by heating. The rubber composition may further contain compounding ingredients such as fillers such as carbon black, silica, and calcium carbonate, silane coupling agents, antioxidants, softeners, processing aids, resins, surfactants, organic acids (such as stearic acid), zinc oxide (zinc white), and vulcanization accelerators.

[0060] The rubber product is preferably at least one selected from the group consisting of rubber tires, rubber crawlers, rubber hoses, conveyor belts, and seismic isolation rubber. Rubber products selected from the group consisting of rubber tires, rubber crawlers, rubber hoses, conveyor belts, and seismic isolation rubber are widely used and produced in large quantities, so using the synthetic rubber obtained by the above-mentioned production method as at least a part of the raw material for rubber products selected from the group consisting of rubber tires, rubber crawlers, rubber hoses, conveyor belts, and seismic isolation rubber can further contribute to promoting the recycling of waste materials including used tires.

[0061] <Method for Producing a Resin Product> The method for producing a resin product of this embodiment is characterized by using a resin obtained by the above-described production method as at least a portion of the raw material for the resin product. Because the method for producing a resin product of this embodiment uses a resin obtained by the above-described production method as at least a portion of the raw material for the resin product, it can contribute to promoting the recycling of waste materials, including used tires. Here, the resin product can be produced, for example, by molding a resin into a desired shape. Alternatively, a resin product can be produced, for example, by preparing a resin composition containing a resin and desired additives in advance and molding the resin composition into a desired shape. Examples of additives that can be added to the resin composition include weather-resistant antioxidants, heat-resistant antioxidants, moist heat-resistant additives, antistatic agents, lubricants, crystal nucleating agents, tackifiers, anti-fogging agents, mold release agents, plasticizers, fillers, dyes, fragrances, and flame retardants.

[0062] The resin product is preferably at least one selected from the group consisting of a resin tire and a resin hose. Since a resin product selected from the group consisting of a resin tire and a resin hose has a high resin content, using the resin obtained by the above-described production method as at least a part of the raw material of the resin product selected from the group consisting of a resin tire and a resin hose can further contribute to promoting the recycling of waste materials including used tires.

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0064] <Sample Preparation> Tire chips made from actual used truck and bus (TBR) tires and used passenger car (PSR) tires were prepared as used tire samples. In addition, model rubbers simulating the composition of used tires were prepared as simulated used tire samples.

[0065] <Production of pyrolysis oil> Pyrolysis furnaces with capacities of 34 L and 0.6 L were prepared, each equipped with an inlet flow path for introducing an inert gas and an outlet flow path for discharging the inert gas and the generated pyrolysis gas. A mass flow controller was attached to the inlet flow path, allowing the amount of inert gas introduced to be adjusted. A pressure relief valve was attached to the outlet flow path, allowing the amount of inert gas and the generated pyrolysis gas discharged to be adjusted.

[0066] The vulcanized rubber sample (tire chip or model rubber) prepared as described above was placed in the pyrolysis furnace, and then the vulcanized rubber sample was placed in the pyrolysis furnace together with the pyrolysis furnace in an electric furnace adjusted to the temperature shown in Tables 1 and 2, to initiate pyrolysis of the vulcanized rubber sample. In Example 5 and Comparative Examples 1 to 9, nitrogen gas was introduced into the pyrolysis furnace through the inlet flow path, and a mixed gas of nitrogen gas and generated pyrolysis gas was extracted from the outlet flow path. The amount of nitrogen gas introduced and the amount of mixed gas of nitrogen gas and pyrolysis gas discharged were adjusted to control the pyrolysis reaction time to the time shown in Tables 1 and 2. The reaction time was calculated from the amount of nitrogen gas introduced, the amount of pyrolysis gas generated, the average molecular weight of the pyrolysis gas, the temperature of the pyrolysis gas, and the volume of the pyrolysis furnace using the following formula: was calculated according to

[0067] Next, the gas obtained from the discharge flow path was cooled to 0 ° C through a condenser, separated into pyrolysis oil and off-gas, and the pyrolysis oil was recovered. From the yield of the recovered pyrolysis oil, the yield of pyrolysis oil based on the mass of the rubber component in the vulcanized rubber sample (raw material) and the yield of pyrolysis oil relative to the pyrolysis gas (yield assuming the yield excluding residue as 100%) were calculated. In addition, the recovered pyrolysis oil was subjected to GC × GC-MS analysis using the following method, and the content of each component was measured. In addition, the distillation properties, iodine value, and density of the recovered pyrolysis oil were measured using the following methods.

[0068] <GC x GC-MS analysis> A two-dimensional gas chromatograph mass spectrometer (GC x GC-MS, manufactured by JEOL, trade name "JEOL JMS-T2000GC", the first dimension was equipped with Agilent Technology's "DB-1 (length 60 m, inner diameter 0.25 mm, film thickness 0.1 μm)" and the second dimension was equipped with Agilent Technology's "DB-17 (length 2 m, inner diameter 0.25 mm, film thickness 0.1 μm)") The component composition of the recovered pyrolysis oil was analyzed using the instrument. Qualitative analysis of the detected peaks was performed, and classification by structure was performed as shown in FIG. 1. Specifically, first, the compounds were classified according to whether they had heteroatoms (S, N, O), and compounds having heteroatoms were designated "hetero compounds". Next, compounds without heteroatoms were classified according to whether they had an aromatic ring. Among compounds having an aromatic ring, those having one aromatic ring were classified as "monocyclic aromatics," those having two aromatic rings as "bicyclic aromatics," and those having three or more aromatic rings as "tricyclic or higher aromatics." Furthermore, among compounds not having an aromatic ring, those having only a single bond were classified as "paraffins," those having a triple bond as "alkynes," and those having a double bond but no triple bond as "olefins."

[0069] <Distillation GC Analysis> The distillation properties of the recovered pyrolysis oil were analyzed using a distillation gas chromatograph (GC) in accordance with ASTM D7169.

[0070] <Measurement of Iodine Value> The iodine value of the recovered pyrolysis oil was measured in accordance with JIS K0070.

[0071] <Measurement of Density> The density of the pyrolysis oil at 40°C was measured in accordance with ASTM D4052.

[0072]

[0073]

[0074] It can be seen from Tables 1 and 2 that the methods of the examples according to the present invention can produce light pyrolysis oil rich in olefins.

[0075] According to the method for producing pyrolysis oil of the present invention, it is possible to efficiently obtain light pyrolysis oil that is rich in olefins. Furthermore, the method for producing pyrolysis oil, the method for producing elastomers, the method for producing rubber products, and the method for producing resin products of the present invention contribute to the recycling of waste materials, including used tires.

Claims

1. A method for producing pyrolysis oil, comprising the steps of: pyrolyzing waste materials, including used tires, in a pyrolysis furnace to obtain a solid material containing pyrolysis gas and char; and cooling the pyrolysis gas to obtain pyrolysis oil, wherein the pyrolysis temperature is 300°C to 500°C, and the pyrolysis reaction time is 0.6 minutes or longer.

2. The method for producing pyrolysis oil according to claim 1, wherein 55 mass% or more of the pyrolysis gas is recovered as pyrolysis oil.

3. The method for producing pyrolysis oil according to claim 1, which does not include a step of further fractionating the pyrolysis oil obtained after cooling the pyrolysis gas.

4. The method for producing pyrolysis oil according to claim 1, wherein the carbonized material comprises carbon black.

5. The method for producing pyrolysis oil according to claim 1, wherein the yield of the pyrolysis oil is 30% or more based on the mass of the waste material.

6. The method for producing pyrolysis oil according to claim 1, wherein the pyrolysis is carried out in an atmosphere of gas generated by pyrolysis.

7. The method for producing pyrolysis oil according to claim 1, wherein the pyrolysis is carried out in an atmosphere of a mixture of an inert gas and a gas generated by pyrolysis.

8. The method for producing pyrolysis oil according to claim 1, wherein the pressure inside the pyrolysis furnace is 0.1 kPaG or less.

9. The method for producing pyrolysis oil according to claim 1, wherein the pressure inside the pyrolysis furnace is 0 kPaG or less.

10. A method for producing an elastomer, characterized in that the pyrolysis oil obtained by the method of claim 1 is used as at least a part of the raw materials for the elastomer.

11. The method for producing an elastomer according to claim 10, wherein the elastomer is at least one selected from the group consisting of resins and synthetic rubbers.

12. A method for producing a rubber product, comprising a vulcanization step of using the synthetic rubber obtained by the method of claim 11 as at least a part of the raw materials for the rubber product, to obtain the rubber product by a vulcanization reaction.

13. The method for producing a rubber product according to claim 12, wherein the rubber product is at least one selected from the group consisting of a rubber tire, a rubber crawler, a rubber hose, a conveyor belt, and a seismic isolation rubber.

14. A method for producing a resin product, characterized in that the resin obtained by the method according to claim 11 is used as at least a part of the raw materials of the resin product.

15. The method for producing a resin product according to claim 14, wherein the resin product is at least one selected from the group consisting of a resin tire and a resin hose.

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