Method and device for producing chemical product

Abstract

A method for producing at least one chemical product selected from the group consisting of C2-C5 olefins and aromatic hydrocarbons, the method comprising: supplying a mixed plastic comprising a polyolefin and at least one plastic selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics, to a fixed-bed reaction zone including a filler layer comprising a packed filler; and pyrolyzing the mixed plastic in the presence of an inert gas while keeping the temperature of the filler layer at 820°C or lower.

Description

Chemical manufacturing method and equipment

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to methods and apparatus for producing chemical products.

[0002] Fixed-bed reactors are widely used due to their simple structure and ease of operation. They are also used in the so-called chemical recycling process, in which plastics are thermally decomposed to extract basic chemicals such as the monomers that make up the raw plastics.

[0003] For example, Patent Document 1 discloses that a fixed-bed treatment device filled with a gallium-containing silicate catalyst can be used in a waste plastic treatment method in which waste plastic is vaporized by pyrolysis, the resulting pyrolysis gas is brought into contact with a gallium-containing silicate catalyst, and a catalytic reaction product is recovered. Specifically, it discloses that granular gallium silicate is filled as a fixed bed, and molten polyethylene is continuously supplied alone and pyrolyzed and vaporized at 425 to 525°C and brought into contact with the gallium silicate, thereby obtaining benzene, toluene, and xylene.

[0004] Furthermore, Patent Document 2 discloses a method for producing olefins, including a step of heating a polyolefin plastic to obtain a decomposition product, and a step of contacting the obtained decomposition product with MFI zeolite containing 0.10% by mass to 0.30% by mass of sodium atoms to obtain a catalytic decomposition product containing olefins. Specifically, it discloses that a downstream reaction tube is filled with MFI zeolite containing sodium atoms, polyethylene, polypropylene, or a mixture thereof is passed from the upstream reaction tube to the downstream reaction tube, and is thermally decomposed at 525°C while being brought into contact with the MFI zeolite containing sodium atoms, thereby obtaining olefins having 2 to 3 carbon atoms.

[0005] In addition, Patent Document 3 discloses a method for thermally decomposing various plastics such as polyethylene, polypropylene, and polystyrene at 500°C in a batch-type fixed-bed reactor filled with a catalyst, to obtain C １ ~C ３ A gas product consisting of olefins and paraffins and a liquid product (mainly C ４＋ ) has been obtained.

[0006] On the other hand, a fluidized bed reactor is generally used as a continuous reactor for producing basic chemicals in a single stage using a mixed plastic containing aromatic plastics such as polystyrene, chlorine-containing plastics such as polyvinyl chloride, and polyolefins as raw materials without intermediate products such as pyrolysis oil, etc. For example, Patent Document 4 discloses that a packed bed reactor, i.e., a fixed bed reactor, can be used in a method for producing olefins and aromatic compounds from a feedstock by introducing a hydrocarbon feedstock such as plastic and a catalyst composition into a reactor, but only a specific example using a fluidized bed reactor is disclosed.

[0007] Japanese Patent Application Laid-Open No. 2001-316517 International Publication No. 2021 / 166854 Special Publication No. 2022-533116 Special Publication No. 2016-513147

[0008] However, the methods described in the prior art documents do not allow useful components such as lower olefins to be obtained in high yields from mixed plastics as a raw material.

[0009] An object of the present disclosure is to provide a method for producing chemical products that can efficiently obtain useful components in high yields.

[0010] The means for solving the above problems are as follows: Namely, <1> A method for producing at least one chemical product selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms, comprising: supplying a mixed plastic containing at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics, and a polyolefin, to a fixed bed reaction section having a filler layer filled with a filler; and thermally decomposing the mixed plastic in the presence of an inert gas by setting the temperature of the filler layer to 820°C or less. <2> In the thermal decomposition, the volume of the filler layer is increased to V (cm ３ ), and the volume of the filler in the filler layer is Vs (cm ３) and a flow rate of the inert gas is v (mL / min), the residence time of the inert gas in the fixed bed reaction section, calculated by the ratio [(V-Vs) / v], is 2 seconds or less. <3> The method for producing a chemical product according to <1> or <2>, wherein, in the thermal decomposition, the temperature of the filler layer is set to 770°C or less. <4> The method for producing a chemical product according to any one of <1> to <3>, wherein, in the thermal decomposition, the porosity of the filler layer is 20% or more and 80% or less. <5> The method for producing a chemical product according to any one of <1> to <4>, wherein the polyolefin contains at least one selected from the group consisting of polyethylene and polypropylene. <6> The method for producing a chemical product according to any one of <1> to <5>, wherein the aromatic-containing plastic contains polystyrene. <7> The method for producing a chemical product according to any one of <1> to <6>, wherein the chlorine-containing plastic contains at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride, and chlorinated polyethylene. <8> In the thermal decomposition, the volume of the filler layer is controlled to V (cm ３ ), and the volume of the filler in the filler layer is Vs (cm ３<9> The method for producing a chemical product according to any one of <1> to <8>, wherein the residence time of the inert gas in the fixed bed reaction section, calculated by the ratio [(V-Vs) / v], is 0.1 seconds or more, where V is the inert gas volume and V is the flow rate of the inert gas (mL / min). <10> The method for producing a chemical product according to any one of <1> to <9>, wherein the temperature of the filler layer in the thermal decomposition is 500°C or more. <11> The method for producing a chemical product according to any one of <1> to <9>, wherein the aromatic hydrocarbon is at least one selected from the group consisting of benzene, toluene, xylene, ethylbenzene, and styrene. <11> An apparatus for producing at least one chemical selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons, comprising: a fixed bed reaction section having a filler layer filled with a filler; a mixed plastic supply section for supplying mixed plastics containing polyolefins and at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics to the fixed bed reaction section; a gas supply section for supplying an inert gas to the fixed bed reaction section; and a heating section for heating the filler layer to a temperature of 820°C or less. <12> The volume of the filler layer is V (cm ３ ), and the volume of the filler in the filler layer is Vs (cm ３The apparatus according to <11>, wherein the gas supply unit supplies the inert gas so that the residence time of the inert gas in the fixed bed reaction unit, calculated by the ratio [(V-Vs) / v], is 2 seconds or less, where Vs is the inert gas volume and v is the flow rate of the inert gas (mL / min). <13> The apparatus according to <11> or <12>, wherein the heating unit heats the filler layer to a temperature of 770°C or less. <14> The apparatus according to any one of <11> to <13>, wherein the porosity in the filler layer is 20% or more and 80% or less. <15> The apparatus according to any one of <11> to <14>, wherein the polyolefin contains at least one selected from the group consisting of polyethylene and polypropylene. <16> The apparatus according to any one of <11> to <15>, wherein the aromatic-containing plastic contains polystyrene. <17> The device according to any one of <11> to <16>, wherein the chlorine-containing plastic contains at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride, and chlorinated polyethylene. <18> The volume of the filler layer is V (cm ３ ), and the volume of the filler in the filler layer is Vs (cm ３ <19> The apparatus according to any one of <11> to <18>, wherein the gas supply unit supplies the inert gas so that a residence time of the inert gas in the fixed bed reaction unit, calculated by the ratio [(V-Vs) / v], is 0.1 seconds or more, where V is the inert gas volume and V is the flow rate of the inert gas (mL / min).

[0011] According to an embodiment of the present disclosure, a method for producing a chemical product that can efficiently obtain useful components in high yield can be provided.

[0012] Fig. 1 is a schematic cross-sectional view showing an example of the apparatus of the present disclosure, and Fig. 2 is a schematic cross-sectional view showing another example of the apparatus of the present disclosure.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the embodiments are not limited by the following description and can be modified as appropriate within the scope of the present disclosure. Furthermore, in this specification, unless otherwise specified, the term "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0014] (Method for producing a chemical product) The method for producing a chemical product of the present disclosure is a method for producing at least one chemical product selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms, and includes supplying a mixed plastic containing at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics, and a polyolefin, to a fixed bed reaction section having a filler layer filled with a filler, and thermally decomposing the mixed plastic in the presence of an inert gas at a temperature of the filler layer of 820°C or less. The method for producing a chemical product of the present disclosure may further include other processes as necessary.

[0015] The methods disclosed in Patent Documents 1 to 3 only disclose methods for thermally decomposing polyolefins alone, and do not disclose methods for efficiently thermally decomposing mixed plastics containing at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics, and polyolefins, to produce useful components in high yields.

[0016] Aromatic plastics and chlorine-containing plastics usually have lower decomposition temperatures than polyolefins. Therefore, when a mixed plastic containing these materials is heated at the decomposition temperature of the polyolefins, the aromatic plastics and chlorine-containing plastics are carbonized. As a result, useful components cannot be obtained from the aromatic plastics and chlorine-containing plastics, resulting in a decrease in the yield of useful components. In addition, when a fixed-bed reactor is used, there is a risk of clogging of the flow paths for the raw materials and decomposition products.

[0017] On the other hand, the fixed bed system has a simple structure and is easy to operate. Therefore, if useful components can be obtained in high yield from mixed plastics in a single reaction stage without producing a large amount of char, it is desirable to adopt the fixed bed system. Although Patent Document 4 discloses that a fixed bed reactor can be used for decomposing mixed plastics, it does not disclose specific reaction conditions when using a fixed bed reactor.

[0018] The present inventors have conducted extensive research and have discovered a method for producing chemical products that can efficiently produce at least one chemical product selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons in high yield from a mixed plastic that contains at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics, and a polyolefin.

[0019] <Chemical Product> The chemical product produced by the method for producing a chemical product according to the present disclosure is at least one selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms. Therefore, in the present disclosure, the term "useful component" means at least one selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms.

[0020] In the present disclosure, olefins having 2 to 5 carbon atoms may be referred to as "lower olefins." In addition, in the present disclosure, aromatic hydrocarbons may be referred to as "useful aromatic hydrocarbons."

[0021] <<Olefins Having 2 to 5 Carbon Atoms>> The olefins having 2 to 5 carbon atoms are preferably at least one selected from the group consisting of alkenes having 2 to 5 carbon atoms and dienes having 2 to 5 carbon atoms, and more preferably alkenes having 2 to 5 carbon atoms.

[0022] An example of an olefin having two carbon atoms is ethylene.

[0023] An example of the olefin having 3 carbon atoms is propylene.

[0024] Examples of olefins having 4 carbon atoms include trans-2-butene, 1-butene, 2-methylpropene, cis-2-butene, 1,3-butadiene, and isobutene.

[0025] Examples of olefins having 5 carbon atoms include trans-2-pentene, 2-methyl-2-butene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, cis-2-pentene, 2-methyl-1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, and 1,3-cyclopentadiene.

[0026] Among these, the method for producing a chemical product according to the present disclosure has the advantage of high yields of ethylene and propylene. The total content (C mol%) of ethylene and propylene in the chemical product is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 35 mol% to 70 mol%, and more preferably 36 mol% to 45 mol%, based on the total number of carbon moles (C mol) in the chemical product.

[0027] In the present disclosure, the content based on the number of moles of carbon is expressed as "C mol %".

[0028] The total content (C mol %) of olefins having 2 to 5 carbon atoms in the chemical product is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 40 mol % or more and 90 mol % or less, more preferably 42 mol % or more and 70 mol % or less, and even more preferably 45 mol % or more and 60 mol % or less, relative to the total number of carbon moles (C mol) in the hydrocarbon-containing composition.

[0029] Olefins having 2 to 5 carbon atoms can be used as basic chemicals suitable for chemical recycling and can be used as raw materials for polyolefins. Polyolefins can be suitably used in various fields, such as plastic bags, plastic wrap films, straws, medical devices, housings for home appliances, erasers, hoses, tires, tubes, CD cases, food trays, food containers, plastic bottles, and fibers.

[0030] <<Aromatic Hydrocarbons>> The aromatic hydrocarbons are not particularly limited, but are preferably benzene, toluene, ethylbenzene, the three positional isomers of xylene (p-xylene, m-xylene, and o-xylene), and styrene, and more preferably the three positional isomers of benzene, toluene, and xylene.

[0031] The total content (C mol%) of aromatic hydrocarbons in the chemical product is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 20 mol% or more and 50 mol% or less, and more preferably 22 mol% or more and 30 mol% or less, relative to the total number of carbon moles (C mol) of the hydrocarbon-containing composition.

[0032] In the present disclosure, benzene, toluene, ethylbenzene, the three positional isomers of xylene (p-xylene, m-xylene, and o-xylene), and styrene may be referred to as "useful aromatic hydrocarbons."

[0033] <<By-Products>> Chemical products obtained by the method for producing a chemical product according to the present disclosure may contain by-products, such as paraffin, carbon, and hydrogen.

[0034] The paraffin is not particularly limited, but examples thereof include saturated aliphatic hydrocarbons having 1 to 5 carbon atoms, and preferably saturated aliphatic hydrocarbons having 2 to 5 carbon atoms. Examples of saturated aliphatic hydrocarbons having 1 to 5 carbon atoms include linear saturated aliphatic hydrocarbons having 1 to 5 carbon atoms.

[0035] Specific examples of paraffins include methane, ethane, propane, iso-butane, n-butane, n-pentane, etc. Among these, the selectivity for methane in the method for producing chemical products according to the present disclosure is low.

[0036] The lower the methane content (C mol%) in the chemical product, the better, but it is more preferably 12 mol% or less, still more preferably 10 mol% or less, and particularly preferably 9 mol% or less, relative to the total number of carbon moles (C mol) in the chemical product. The lower limit of the methane content in the chemical product is preferably 0.1 mol% or more, relative to the total number of carbon moles (C mol) in the chemical product.

[0037] The total content (C mol%) of paraffins having 1 to 5 carbon atoms in the hydrocarbon-containing composition is preferably 35 mol% or less, more preferably 30 mol% or less, and even more preferably 10 mol% or less, relative to the total number of carbon moles (C mol) in the hydrocarbon-containing composition. The lower limit of the total content (C mol%) of paraffins having 1 to 5 carbon atoms in the hydrocarbon-containing composition is preferably 0.1 mol% or more, relative to the total number of carbon moles (C mol%) in the hydrocarbon-containing composition.

[0038] -O / P Ratio- In the present disclosure, the low content of paraffins as by-products can be evaluated by determining the ratio of the total content of olefins (C mol%) in a chemical product to the total content of paraffins (C mol%) in the chemical product, i.e., the ratio [total content of olefins (C mol%) / total content of paraffins (C mol%)] (hereinafter, sometimes referred to as "O / P ratio"). In the production method of a chemical product of the present disclosure, the ratio [total content of olefins (C mol%) / total content of paraffins (C mol%)] is evaluated by the ratio [total content of olefins having 2 to 5 carbon atoms (C mol%) / total content of paraffins having 2 to 5 carbon atoms (C mol%)].

[0039] The O / P ratio of those having 2 to 5 carbon atoms is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 or more, and more preferably 10 or more. Since a higher O / P ratio is more preferable, the upper limit of the O / P ratio of those having 2 to 5 carbon atoms is not particularly limited, but is preferably 50 or less, and more preferably 20 or less.

[0040] The content of useful components contained in the chemical product and the O / P ratio of carbon atoms having 2 to 5 carbon atoms can be determined by analyzing the gaseous product and liquid substance obtained by the method for producing a chemical product of the present disclosure using a gas chromatograph (GC) device equipped with a flame ionization detector.

[0041] When analyzing the gaseous product as a product, the analysis is carried out by gas chromatography (GC) equipped with a flame ionization detector under the analytical conditions described in the Examples, and each component can be quantified by the internal standard method from the ratio of the peak area of ​​each component to that of the internal standard. The internal standard is not particularly limited as long as it is stable under the analytical conditions and can be easily separated from the component to be analyzed, and an example of the internal standard is cyclopentane.

[0042] When analyzing a liquid substance as a product, the analysis is carried out by gas chromatography (GC) equipped with a flame ionization detector under the analytical conditions described in the Examples, and each component can be quantified by the internal standard method from the ratio of the peak area of ​​each component to that of the internal standard. The internal standard is not particularly limited as long as it is stable under the analytical conditions and can be easily separated from the component to be analyzed, and an example of the internal standard is cyclopentane.

[0043] Furthermore, the content of residues such as coking, which are by-products contained in the product, can be calculated by air-combusting the filler layer inside the fixed-bed reaction section, or by extracting the filler constituting the filler layer from the fixed-bed reaction section and air-combusting it, and measuring the change in weight before and after air-calcination.

[0044] (Feeding to the fixed bed reaction section) Feed to the fixed bed reaction section means feeding a mixed plastic containing at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics, and a polyolefin, to a fixed bed reaction section having a filler layer filled with a filler.

[0045] The method for supplying the mixed plastics to the fixed bed reaction section is not particularly limited, and may be either intermittent or continuous. Among these, intermittent supply is preferred as the method for supplying the mixed plastics to the fixed bed reaction section, since it can reduce temperature changes in the filler layer.

[0046] When the mixed plastics are intermittently fed to the fixed bed reaction section, there are no particular limitations on the feeding time and non-feeding time of the mixed plastics and the intervals therebetween.

[0047] When mixed plastics are intermittently supplied to the fixed bed reaction section, there are no particular restrictions on the amount of mixed plastics supplied per time, but if the mass of filler filled in the filler layer is "Wf" (g) and the amount of mixed plastics supplied per time is "Ws" (g), the ratio of Ws to Wf [Ws / Wf] is preferably 0.001 to 0.05, more preferably 0.002 to 0.02, and even more preferably 0.005 to 0.015. When the ratio [Ws / Wf] is within the range of 0.001 to 0.05, the temperature change during supply of mixed plastics to the filler layer is small, and useful components can be obtained efficiently and in high yield.

[0048] When mixed plastics are intermittently supplied to the fixed bed reaction section, in order to prevent the temperature of the filler layer from dropping too much, it is preferable that the second or subsequent addition of mixed plastics be made after the temperature of the filler layer, which has dropped in the previous addition, has recovered and reached 680°C or higher.

[0049] When mixed plastics are continuously supplied to the fixed bed reaction section, there are no particular restrictions on the amount of mixed plastics supplied, but if the mass of filler filled in the filler layer is "Wf" (g) and the amount of mixed plastics supplied per minute is "Wsc" (g / min), the ratio of Wsc to Wf [Wsc / Wf·min] is preferably 0.00025 to 0.0125, more preferably 0.0005 to 0.005, and even more preferably 0.00125 to 0.00375. When the ratio [Wsc / Wf·min] is within the range of 0.00025 to 0.0125, the temperature change during supply of mixed plastics to the filler layer is small, and useful components can be obtained efficiently and in high yield.

[0050] <Mixed Plastic> The mixed plastic contains at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics, and a polyolefin. The mixed plastic may further contain other components as necessary.

[0051] <<Aromatic-containing plastics>> Aromatic-containing plastics are plastics having an aromatic skeleton. There are no particular limitations on the aromatic-containing plastics, and they can be appropriately selected depending on the purpose from those commonly used for beverage and food containers, packaging materials, molded articles, films, etc. Examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), acrylonitrile-butadiene-styrene copolymers, polycarbonate (PC), polystyrene (PS), etc. These may be contained alone or in combination of two or more. Among these, it is preferable that the aromatic-containing plastic contains polystyrene (PS).

[0052] <<Chlorine-containing plastic>> The chlorine-containing plastic is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the chlorine-containing plastic contains at least one selected from the group consisting of polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), and chlorinated polyethylene (CPE), which are widely used in beverage and food containers, packaging materials, molded products, films, etc.

[0053] The content of at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics in the mixed plastics is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 10% by mass or more and 50% by mass or less, and more preferably 15% by mass or more and 40% by mass or less, relative to the total mass of the mixed plastics. When the content of at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics in the mixed plastics is 10% by mass or more and 50% by mass or less, at least one chemical product selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms can be obtained efficiently in high yield.

[0054] <<Polyolefin>> The polyolefin is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the polyolefin contains at least one selected from the group consisting of polyethylene (PE) and polypropylene (PP), which are widely used in beverage and food containers, packaging materials, molded products, films, etc.

[0055] The polyolefin content in the mixed plastic is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 50% by mass or more and 90% by mass or less, and more preferably 60% by mass or more and 85% by mass or less, relative to the total mass of the mixed plastic. When the polyolefin content in the mixed plastic is 50% by mass or more and 90% by mass or less, it is possible to use easily available mixed plastics without sorting, and it is also possible to efficiently obtain at least one chemical product selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons with a high yield.

[0056] <<Other Components>> The other components contained in the mixed plastic are not particularly limited and can be selected appropriately depending on the purpose, and examples include at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics, other plastics other than polyolefins, and materials typically contained in waste plastics such as paper and metal. These may be contained alone or in combination of two or more.

[0057] The other plastics are not particularly limited and can be appropriately selected depending on the purpose. Examples include polyamide, polyurethane, and polymethyl methacrylate.

[0058] The content of other components in the mixed plastic is not particularly limited and can be selected appropriately depending on the type of mixed plastic used, etc., but from the viewpoint of the yield of at least one chemical product selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms, it is preferable that the content be less than 30 mass% of the total mass of the mixed plastic, more preferably 25 mass% or less, and even more preferably 20 mass% or less.

[0059] From the viewpoint of reducing the environmental load, the mixed plastic preferably contains waste plastic. When the mixed plastic is waste plastic, the composition and composition ratio are not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that PE is 20% to 40% by mass, PP is 20% to 40% by mass, and PS is 10% to 30% by mass.

[0060] The structure and content of each component contained in the mixed plastic can be determined by analysis using, for example, gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), liquid chromatography mass spectrometry (LC-MS), pyrolysis gas chromatography mass spectrometry (PyGC-MS), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS), etc.

[0061] When the mixed plastics are supplied to the fixed bed reaction section, the state of the mixed plastics to be supplied to the fixed bed reaction section is not particularly limited, and examples thereof include crystalline, glassy, ​​rubbery, liquid, and undecomposed states. The mixed plastics may also be in the form of decomposed products. Among these, rubbery or liquid mixed plastics are preferred, and undecomposed plastics are more preferred, from the viewpoints of easily controlling the supply amount and obtaining a hydrocarbon composition from waste plastics in fewer steps.

[0062] When the mixed plastics are crystalline or glassy, ​​there are no particular limitations on the form thereof, and examples thereof include crushed mixed plastics, pellets of crushed mixed plastics, chips of crushed mixed plastics, and the like.

[0063] The crushed mixed plastics may be in any form, such as powder or flakes, and may be selected appropriately depending on the purpose without any particular limitation.

[0064] A rubbery or liquid mixed plastic refers to a plastic that is in a fluid state at a temperature equal to or higher than the melting point of the mixed plastic and lower than the thermal decomposition temperature of the mixed plastic. A rubbery or liquid mixed plastic is also called a "melt of the mixed plastic."

[0065] Decomposition products of mixed plastics are materials that have been reduced in molecular weight from mixed plastics, but have a larger molecular weight than the final chemical product, and are typically obtained by heating mixed plastics at a temperature of 300°C or higher but lower than 500°C.

[0066] The molecular weight of rubbery or liquid mixed plastics does not change from the molecular weight of crystalline or glassy mixed plastics of the same composition. Therefore, mixed plastics and their decomposition products can be distinguished by molecular weight. As the molecular weight decreases due to decomposition, the melting point decreases, so in practice, the melting temperature can be used to determine the quality. The melting temperature is measured using the method specified in JIS K7121-2012.

[0067] The melting point of the mixed plastic is not particularly limited and can be appropriately selected depending on the raw materials used, but is preferably 80°C to 200°C, more preferably 90°C to 190°C.

[0068] These mixed plastics in various forms may be used after being treated separately from the chemical product manufacturing method of one embodiment, or after being subjected to other treatments described below.

[0069] <Fixed Bed Reaction Section> The fixed bed reaction section has a filler layer filled with a filler, and may further have other layers as necessary.

[0070] <<Filler Layer>> The filler layer is formed by filling the reaction section with a filler. The filler layer forms a fixed bed in the fixed bed reaction section.

[0071] The filler layer preferably has a certain amount of voids in order to ensure a flow path for the mixed plastics and the inert gas during pyrolysis. The porosity φ of the filler layer is not particularly limited and can be appropriately set depending on the properties of the mixed plastics used, the conditions for pyrolysis, etc., but from the viewpoint of ensuring a sufficient flow path for the mixed plastics and the inert gas and sufficient contact between the filler and the mixed plastics, it is preferably 20% to 80%, more preferably 30% to 70%, and even more preferably 40% to 60%.

[0072] In the present disclosure, the "porosity φ" is the ratio of voids in a filler layer, and is calculated based on the following formula 1 and formula 2: [Formula 1] Porosity φ (%) = (1 - Vs / V) × 100 (In formula 1, "Vs" is the volume (cm) of the filler calculated by formula 2 below). ３ ), and "V" is the volume of the filler layer (cm ３ ) where the volume of the filler layer is the volume of the filler packed section in the fixed bed reaction section.) [Equation 2] Vs = Wf / TD (In Equation 2, "Wf" represents the mass (g) of the filler packed in the filler layer, and "TD" represents the true density (g / cm ３ ) indicates.

[0073] The shape and structure of the filler layer are not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of enabling the smooth flow of the mixed plastics and the produced chemical products and ensuring sufficient contact time between the mixed plastics and the filler, it is preferable that the flow direction of the mixed plastics is perpendicular to the flow direction, i.e., longer than the inner diameter of the fixed bed reaction section.

[0074] Filler The filler is used to maintain the temperature of the reaction system at a constant temperature during pyrolysis.

[0075] There are no particular restrictions on the filler, and it can be selected appropriately depending on the purpose, but it is preferable that the filler is a material that is stable in the temperature range of pyrolysis, is not subject to reduction by by-products such as carbon and hydrogen produced by the pyrolysis of the mixed plastic, and does not react with inert gases.

[0076] Specific examples of fillers include zirconium oxide, yttria-stabilized zirconium oxide, calcia-stabilized zirconium oxide, magnesium oxide, calcium oxide, silicon carbide, silicon nitride, silicon oxide, aluminum oxide, tantalum oxide, niobium oxide, beryllium oxide, lanthanum oxide, manganese (II) oxide, chromium (III) oxide, gallium oxide, forstenite, and cordierite. The filler may also be a surface-treated version of the above materials for purposes such as surface inactivation and improving the fluidity of mixed plastics. These materials may be used alone or in combination. Among these, it is preferable to use one or more of silicon carbide, aluminum oxide, silicon oxide, or surface-treated versions of these fillers. It is more preferable to use one or more fillers selected from the group consisting of silicon carbide and aluminum oxide, which have an inactive surface that does not catalyze the oxidative decomposition reaction of water vapor with hydrocarbons and the carbon deposition reaction, and have good thermal conductivity.

[0077] The surface-treated filler is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include fillers having an oxide film on the surface, fillers having a carbon film on the surface, etc. Among these, as the surface-treated filler, fillers having a carbon film on the surface are preferred from the viewpoint that active sites due to the surface treatment are less likely to be generated and side reactions can be prevented.

[0078] The method for surface treating the filler is not particularly limited, and can be appropriately selected from known methods.

[0079] For example, when preparing a filler having an oxide film on the surface, a method of forming an oxide film on the surface of the filler by oxidation can be used.

[0080] Furthermore, when preparing a filler having a carbon film on its surface, a method can be mentioned in which an organic compound is attached to the surface of the filler, and then the filler is fired in the presence of an inert gas to form a carbon film. When preparing a filler having a carbon film on its surface, it is preferable to use a hydroxycarboxylic acid as the organic compound, from the viewpoint of facilitating the formation of a uniform and homogeneous carbon film.

[0081] The hydroxycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include malic acid, citric acid, tartaric acid, gallic acid, salicylic acid, etc. These may be used alone or in combination of two or more.

[0082] The structure of the surface-treated filler can be confirmed by, for example, observation with a scanning electron microscope (SEM), observation with a transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, or the like.

[0083] The coverage of the filler with the carbon film in a filler having a carbon film on its surface is not particularly limited and can be selected appropriately depending on the purpose. However, the mass ratio of the carbon forming the carbon film to the filler [carbon / filler] is preferably 0.0001 to 0.5, more preferably 0.001 to 0.1, even more preferably 0.001 to 0.1, and particularly preferably 0.002 to 0.08. A mass ratio [carbon / filler] of 0.0001 to 0.5 effectively promotes contact between the fillers and allows efficient pyrolysis of the mixed plastic within the pyrolysis temperature range. The mass ratio [carbon / filler] is calculated from the mass of the organic compound serving as the carbon source in the filler having a carbon film on its surface and the mass of the filler. Therefore, the filler may be completely or partially covered by the carbon film. Therefore, the carbon film may be not only layer-like but also appear as islands in a sea upon surface observation.

[0084] In a filler having a carbon film on the surface thereof, the coverage of the filler with the carbon film can be confirmed by a method of calculation from the charged amount, a method of analyzing the weight change of the carbon film based on the weight change by thermogravimetric differential thermal analysis (TG-DTA), or the like.

[0085] The size of the filler is not particularly limited and can be appropriately selected depending on the purpose, but the nominal opening is preferably 90 μm to 125 mm, more preferably 125 μm to 90 mm. The size of the filler is measured in accordance with JIS Z 8801-1:2019.

[0086] The shape and structure of the filler are not particularly limited and can be selected appropriately depending on the purpose, but the shape of the filler is preferably one that makes it difficult for the molten mixed plastic to remain on the filler, and is preferably spherical, and more preferably a true sphere.

[0087] (Pyrolysis) Pyrolysis involves pyrolyzing the mixed plastic in the presence of an inert gas at a temperature of the filler layer of 820° C. or less. By pyrolysis, at least one chemical product selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms can be obtained.

[0088] In the thermal decomposition, the temperature of the filler layer is not particularly limited as long as it is 820°C or less, but is preferably 770°C or less. When the temperature of the filler layer is 820°C or less, useful components can be obtained efficiently with a high yield. Furthermore, when the temperature of the filler layer is 770°C or less, the generation of methane, a by-product produced by the decomposition of mixed plastics that is difficult to use as a basic chemical, can be suppressed.

[0089] In the thermal decomposition, the lower limit of the temperature of the filler layer is not particularly limited as long as it can decompose the mixed plastics, and can be appropriately selected depending on the purpose, but is preferably 500° C. or higher, more preferably 580° C. or higher, and even more preferably 650° C. or higher. In the thermal decomposition, if the temperature of the filler layer is 500° C. or higher, useful components can be obtained efficiently at a high yield.

[0090] In the thermal decomposition, the upper and lower limit values ​​of the temperature of the filler layer can be appropriately combined, but is preferably 500°C or higher and 820°C or lower, more preferably 580°C or higher and 820°C or lower, and even more preferably 650°C or higher and 770°C or lower.

[0091] <Inert Gas> There are no particular limitations on the inert gas, but it is preferable to use an inert gas that is stable in the temperature range of thermal decomposition.

[0092] Specific examples of the inert gas include nitrogen gas, water vapor, carbon dioxide, and rare gases. These may be used alone or in combination of two or more. Among these, the inert gas is preferably one or more selected from the group consisting of nitrogen gas and water vapor, and more preferably nitrogen gas, because it is inexpensive.

[0093] In the thermal decomposition, the flow rate of the inert gas is not particularly limited and can be appropriately selected depending on the purpose. ３ ), and the volume of the filler in the filler layer is Vs (cm ３ ), and the flow rate of the inert gas is v (mL / min), the flow rate is preferably such that the residence time t of the inert gas in the fixed bed reaction section, calculated by the ratio [(V-Vs) / v], is 2.5 seconds or less, and more preferably 2 seconds or less. When the flow rate of the inert gas is such that the residence time t of the inert gas is 2.5 seconds or less, sufficient contact time between the mixed plastic and the filler can be ensured and side reactions can be suppressed, resulting in efficient production of useful components at a high yield. Vs is calculated using Equation 2:

[0094] There is no particular restriction on the lower limit of the flow rate of the inert gas, but from the viewpoint of ensuring sufficient contact time between the mixed plastic and the filler and efficiently obtaining useful components at a high yield, a flow rate that results in a residence time t of the inert gas in the fixed bed reaction section of 0.1 seconds or more is preferred, a flow rate that results in a residence time t of 0.5 seconds or more is more preferred, and a flow rate that results in a residence time t of 1 second or more is even more preferred.

[0095] The upper and lower limit values ​​of the flow rate of the inert gas can be appropriately combined, but a flow rate that results in a residence time t of the inert gas in the fixed bed reaction section of 0.1 seconds or more and 4.0 seconds or less is preferred, a flow rate that results in a residence time t of the inert gas in the fixed bed reaction section of 0.5 seconds or more and 2.5 seconds or less is more preferred, and a flow rate that results in a residence time t of 1 second or more and 2 seconds or less is even more preferred.

[0096] (Other Treatments) The method for producing a chemical product according to the present disclosure may further include other treatments in addition to supplying the reaction mixture to the fixed bed reaction section and pyrolysis, as necessary.

[0097] The other treatments are not particularly limited and can be selected appropriately depending on the purpose. Examples include pre-treating mixed plastics, recovering chemical products obtained by thermal decomposition, and separating chemical products.

[0098] <<Pretreatment>> Pretreatment involves pretreating mixed plastics before they are supplied. Pretreatment puts the mixed plastics into a form or state that makes them easier to decompose, allowing the mixed plastics to be decomposed more efficiently.

[0099] Examples of pretreatment include crushing the mixed plastics, pelletizing (chipping) the crushed mixed plastics, and melting the mixed plastics.

[0100] The melt processing of the mixed plastics is preferably carried out at a temperature below 300°C.

[0101] The crushed mixed plastics may be in any form, such as powder or flakes, and may be selected appropriately depending on the purpose without any particular limitation.

[0102] The method for obtaining pulverized mixed plastics is not particularly limited and can be appropriately selected from conventionally known methods, such as a method in which mixed plastics are pulverized using a pulverizer to obtain powder or flakes.

[0103] Furthermore, the method for pelletizing the pulverized material (chips) is not particularly limited and can be appropriately selected from conventionally known methods, such as a method in which the pulverized material is melt-extruded and then the strand-like molten extruded material is cut to obtain chipped raw material.

[0104] The mixed plastics can also be supplied in a molten state. The method for melting the mixed plastics is not particularly limited and can be appropriately selected from conventionally known methods, such as a method in which the mixed plastics are continuously supplied to the decomposition step using a melt extruder.

[0105] <<Recovering>> In recovering, liquid substances and gases, which are products containing chemical products obtained by thermal decomposition, are recovered. The recovery method is not particularly limited and can be appropriately selected from known methods depending on the type of product obtained. For example, gaseous products are separated by atmospheric or pressurized distillation, and liquid hydrocarbons are separated by atmospheric or reduced pressure distillation.

[0106] <<Separation>> In separation, only useful components are separated from the liquid substance and gas recovered in the recovery process, and unnecessary components are removed.

[0107] The substances produced by the method for producing a chemical product disclosed herein may include at least one selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons, as well as a minor component, paraffin having 2 to 5 carbon atoms.

[0108] In the separation, the method for separating the useful components from the minor components is not particularly limited, and can be appropriately selected from known methods depending on the type of the obtained product or the type of the minor components.

[0109] The above-described method for producing a chemical product makes it possible to efficiently produce at least one chemical product selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms in high yield. The produced chemical product can be used as a basic chemical product suitable for chemical recycling.

[0110] (Apparatus) The apparatus of the present disclosure is an apparatus for producing at least one chemical selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons, and includes a storage section for mixed plastics containing polyolefins and at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics, a fixed-bed reaction section having a filler layer filled with filler, a mixed plastic supply section that supplies the mixed plastics in the storage section to the fixed-bed reaction section, a gas supply section that supplies an inert gas to the fixed-bed reaction section, and a heating section that heats the filler layer to a temperature of 820° C. or less. The apparatus of the present disclosure may further include other components as necessary.

[0111] The apparatus of the present disclosure can suitably carry out the method for producing a chemical product of the present disclosure.

[0112] (First Embodiment) Hereinafter, an embodiment of the device of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the device of the present disclosure. The embodiment shown below illustrates a device for embodying the technical concept of the present disclosure and is not intended to limit the present disclosure to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, in order to avoid overly complex drawings, schematic cross-sectional views are used in which some elements are omitted.

[0113] The apparatus 100 comprises a fixed bed reaction section 1 having a filler layer 2 , a mixed plastics supply section 3 , a gas supply section 4 , and a heating section 5 .

[0114] <Fixed Bed Reaction Section> The fixed bed reaction section 1 is a member having a filler layer 2 filled with filler 2a. The structure, shape, material, and size of the fixed bed reaction section 1 are not particularly limited as long as they can accommodate the filler layer 2 and can pass a raw material M containing a mixed plastic containing a polyolefin and at least one selected from the group consisting of an aromatic plastic and a chlorine-containing plastic. These structures can be appropriately selected depending on the purpose, and examples include cylindrical tubes. To retain the filler in the tube, the tube may be plugged with a material that allows the flow of an organic compound, such as glass wool.

[0115] <Mixed Plastic Supply Section> The mixed plastic supply section 3 is a member that supplies the raw material M containing mixed plastics to the fixed bed reaction section 1. Examples of the mixed plastic supply section 3 include a raw material circulation section 3a that circulates the raw material M containing mixed plastics, and a raw material introduction section 3b that introduces the raw material M containing mixed plastics into the fixed bed reaction section 1. The mixed plastic supply section 3 may supply the raw material M to the fixed bed reaction section 1 using a known pump or the like.

[0116] The mixed plastics supply section 3 may also have a raw material supply stopping section such as a stopper that can stop the supply of raw material M containing mixed plastics. When the mixed plastics supply section 3 has a raw material supply stopping section, the mixed plastics can be intermittently supplied to the fixed bed reaction section 1. The raw material supply stopping section can be disposed, for example, at the inlet of the raw material input section 3b.

[0117] <Gas Supply Section> The gas supply section 4 is a member that supplies the inert gas G to the fixed bed reaction section 1. Examples of the gas supply section 4 include a gas flow section 4a that flows the inert gas G and a pump 4b that flows the inert gas G at a constant amount for a constant period of time.

[0118] <Heating Unit> The heating unit 5 is a member that heats the filler layer 2 to a temperature of 820°C or less. The heating unit 5 is not particularly limited and may be an external heating type that heats the filler layer by heat transfer from the outside, or an internal heating type that causes the filler layer itself to generate heat. As a heating unit of an external heating type, for example, a known electric furnace can be used. As a heating unit of an internal heating type, for example, a resistance heating type can be used in which a conductor such as silicon carbide is used as the filler, electrodes are attached to both ends of the filler layer, and a voltage is applied between the electrodes to generate heat.

[0119] The temperature of the filler layer 2 can be measured by inserting a thermocouple into the center of the filler layer 2 .

[0120] <Other Components> The other components are not particularly limited and can be appropriately selected depending on the purpose. Examples include a storage section 6, a cooling section 7, a gaseous product recovery section 8, and a measurement section that measures the yield of useful components.

[0121] <<Storage section>> The storage section 6 is a member for storing raw material M containing a mixed plastic containing polyolefin and at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics, and further containing other components as necessary.

[0122] The structure, shape, material, and size of the storage section 6 are not particularly limited as long as they are capable of storing the raw material M including the mixed plastics, and can be appropriately selected depending on the purpose.

[0123] The number of storage units 6 is not particularly limited and may be one or more. When the device 100 has a plurality of storage units 6, it can be used to store mixed plastics containing, for example, polyolefin and at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics, in which the compositions and contents of the components are different.

[0124] <<Cooling Section>> The cooling section 7 is a member that cools the product obtained after passing through the fixed bed reaction section 1. The cooling section 7 is preferably disposed between the fixed bed reaction section 1 and the gaseous product recovery section 8.

[0125] Examples of the cooling unit 7 include a trap 7a that cools the product, a cold insulation unit 7b that cools the trap 7a, etc. The structure, shape, material, and size of the trap 7a and the cold insulation unit 7b are not particularly limited as long as they can cool the product, and can be appropriately selected depending on the purpose.

[0126] The trap 7a may contain an organic solvent 7c that dissolves the product. The organic solvent 7c can condense useful components in the product, particularly useful components in liquid form. The organic solvent that dissolves the product is preferably a non-aqueous solvent. Examples of non-aqueous solvents include aromatic organic solvents such as monochlorobenzene, o-dichlorobenzene, and mesitylene.

[0127] The useful components dissolved in the non-aqueous solvent can be suitably separated by further distillation at atmospheric pressure.

[0128] The cold insulation part 7b is not particularly limited as long as it can cool the trap 7a, and may contain, for example, a refrigerant 7d, such as ice water.

[0129] <<Gaseous product recovery section>> The gaseous product recovery section 8 is a component that recovers the gaseous product containing useful components produced by the apparatus 100. The apparatus may have only one gaseous product recovery section 8, or two or more gaseous product recovery sections 8.

[0130] The structure, shape, material, and size of the gaseous product recovery section 8 are not particularly limited and may be appropriately selected depending on the purpose and the type of product, and examples thereof include known containers.

[0131] A solvent or the like capable of separating useful components may also be contained in the gaseous product recovery section 8. The solvent is not particularly limited and can be appropriately selected depending on the type of useful components to be recovered. For example, solvents for extracting useful components from a liquid product include ethanol, hexane, dimethylformamide, cyclopentane, and water.

[0132] The useful components in the gaseous product can be suitably separated by further pressure distillation.

[0133] <<Measuring Unit>> The measuring unit is a component that measures the yield of the useful component in the product containing the useful component produced by the apparatus 100 .

[0134] The measurement unit may be provided inside the device 100 or may be provided outside the device 100 and connected thereto.

[0135] The measuring unit is not particularly limited as long as it can measure the yield of useful components in the product, and any known measuring device may be used, such as a flame ionization detector (FID) or a thermal conductivity detector (TCD).

[0136] The structure, shape, material, and size of the measurement unit are not particularly limited and can be appropriately selected depending on the purpose and the type of product.

[0137] The apparatus 100 can carry out the supplying step in the compound production method of the present disclosure by, for example, supplying a raw material M containing a mixed plastic containing at least one selected from the group consisting of an aromatic-containing plastic and a chlorine-containing plastic, and a polyolefin, stored in a storage section 6, to a fixed bed reaction section 1 via a mixed plastic supply section 3. The fixed bed reaction section 1 functions as a fixed bed reactor in the compound production method of the present disclosure.

[0138] Thereafter, while supplying an inert gas G from the gas supply unit 4 to the fixed bed reaction unit 1, the fixed bed reaction unit 1 is heated in the heating unit 5 to a temperature of 820°C or less, thereby carrying out the heating step in the method for producing a compound of the present disclosure.

[0139] The product containing useful components obtained by heating can be recovered and separated in the cooling section 7 and the gas product recovery section 8 in the method for producing the compound of the present disclosure.

[0140] The chemicals produced by the apparatus 100 of the present disclosure are as described in the methods for producing compounds of the present disclosure.

[0141] Second Embodiment Fig. 2 is a schematic cross-sectional view showing another example of the apparatus of the present disclosure. The apparatus according to the second embodiment is the same as the apparatus according to the first embodiment, except that the configuration of the cooling unit 7 is different.

[0142] In the apparatus according to the second embodiment, the product outlet of the tube connected to the fixed bed reaction section 1, which is disposed in the trap 7a of the cooling section 7, is disposed in the organic solvent 7c, so that the gaseous product bubbles in the organic solvent 9c.

[0143] The present disclosure will be specifically described below with reference to examples and comparative examples, but the present disclosure is not limited to these examples and comparative examples.

[0144] Example 1 Preparation of Mixed Plastics Polyethylene (Hi-Zex (registered trademark) 1300J, manufactured by Prime Polymer Co., Ltd.), polypropylene (Prime Polypro (registered trademark) J108M, manufactured by Prime Polymer Co., Ltd.), and polystyrene (PSJ-Polystyrene (registered trademark) SGP10-K3900, manufactured by PS Japan Co., Ltd.) were mixed at a ratio of 1:1:1 (w / w) to prepare a mixed plastic. The prepared mixed plastic is shown in Tables 1 and 2 as "PE+PP+PS."

[0145] <Preparation of Apparatus> A quartz tube with an inner diameter of 2.2 cm was filled with silicon carbide particles (SiC) (trade name: Carborundum, 16 mesh (particle size: 1.119 mm), manufactured by Tokoyaku Co., Ltd.) as a filler to a filling length of 6 cm. 35 g of silicon carbide particles were used. The quartz tube was set in a tubular furnace (trade name: ARF-30MC, manufactured by Asahi Rika Seisakusho) installed vertically. A manual powder feeder (airless feed cock, manufactured by Asahi Seisakusho Co., Ltd.) for introducing the mixed plastic and a gas inlet were connected to the top of the tubular furnace, and connected to the inlet side of the quartz tube. One end of a gas outlet pipe was connected to the bottom of the tubular furnace. The other end of the gas outlet pipe was connected to the inlet side of a cooling trap containing 15 mL of o-dichlorobenzene (special grade reagent, manufactured by Kanto Chemical Co., Ltd.). The cooling trap was placed in an ice bath. One end of another gas outlet pipe was connected to the outlet side of the cooling trap, and the other end of the other gas outlet pipe was connected to a gas bag (volume 10 L). A thermocouple was inserted into the center of the silicon carbide packed into the quartz tube. Nitrogen gas was blown in through the gas inlet at a flow rate of 400 mL / min, and the temperature of the tubular furnace was set to 700 °C and heating began.

[0146] <Decomposition of Mixed Plastics> After the furnace temperature reached the set point of 700°C and stabilized, 0.33 g of mixed plastic was fed into the quartz tube from the manual powder feeder over a 4-minute period under a nitrogen flow rate of 400 mL / min. This process was repeated six times. Subsequent feeding of mixed plastics was performed after the furnace temperature had recovered to a range of 680°C to 700°C. After the total of 1.98 g of mixed plastics had been fed, the generated gas was collected in a gas bag. Five minutes after the end of the mixed plastic feeding, the gas bag was detached from the device. The cold trap was then allowed to return to room temperature (25°C ± 5°C) for approximately three minutes before being detached from the device.

[0147] Example 2 The decomposition of mixed plastics was carried out in the same manner as in Example 1, except that the temperature set in the furnace was changed from 700°C to 750°C.

[0148] Example 3 The decomposition of mixed plastics was carried out in the same manner as in Example 1, except that the temperature set in the furnace was changed from 700°C to 800°C.

[0149] Example 4 The mixed plastics were decomposed in the same manner as in Example 1, except that the time for feeding the mixed plastics per feeding was changed from 4 minutes to 3 minutes.

[0150] Example 5 The decomposition of mixed plastics was carried out in the same manner as in Example 1, except that the flow rate of nitrogen gas was changed from 400 mL / min to 200 mL / min.

[0151] Example 6 The decomposition of mixed plastics was carried out in the same manner as in Example 1, except that the flow rate of nitrogen gas was changed from 400 mL / min to 500 mL / min.

[0152] (Example 7) In Example 1, 35 g of silicon carbide particles were packed into the quartz tube, but aluminum oxide particles (Al ２ O ３ The mixed plastics were decomposed in the same manner as in Example 1, except that 36 g of alumina balls (trade name: Alumina Ball HD-3, diameter: 30 mm, manufactured by Nikkato Corporation) were filled in the container.

[0153] (Example 8) In Example 1, 35 g of silicon carbide particles was filled in the quartz tube, and the same was repeated except that 35 g of silicon carbide particles was filled in the quartz tube using zirconium oxide / silicon oxide mixture particles (trade name: Zircodiabol CZS 0160, diameter: 1.40 mm to 1.60 mm, manufactured by AS ONE Corporation, composition: ZrO ２ / 55% to 65%, SiO ２ The mixed plastics were decomposed in the same manner as in Example 1, except that 55 g of ethanol (35% to 45%) was added.

[0154] (Example 9) The decomposition of mixed plastics was carried out in the same manner as in Example 1, except that the type of filler was changed from silicon carbide particles to carbon-coated silicon carbide particles (sometimes referred to as "surface-treated SiC") produced by the following method.

[0155] <Production of Carbon-Coated Silicon Carbide Particles> 0.50 g of citric acid monohydrate (citric acid monohydrate, special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 10 g of ethanol (special grade, manufactured by Kanto Chemical Co., Ltd.) were weighed into a 250 mL container with a lid, and the mixture was stirred until the citric acid was completely dissolved. 66 g of silicon carbide particles (trade name: Densic C, particle size (JIS R 6001-1-2017) F10, manufactured by Resonac Co., Ltd.) were added to the container and stirred so that the solution covered the entire silicon carbide particles. The container's lid was removed and the mixture was placed in a vacuum dryer, and the pressure was reduced to less than 20 kPa at room temperature for drying. The container was removed from the vacuum dryer and stirred every few minutes until completely dried. The completely dried mixture was placed in an alumina boat and calcined at 800 °C for 1 hour in a nitrogen gas stream to obtain carbon-coated silicon carbide particles.

[0156] Example 10 The decomposition of mixed plastics was carried out in the same manner as in Example 9, except that the flow rate of nitrogen gas was changed from 400 mL / min to 200 mL / min.

[0157] Comparative Example 1 The decomposition of mixed plastics was carried out in the same manner as in Example 1, except that the temperature set in the furnace was changed from 700°C to 850°C.

[0158] <<Analysis of Gas Bag Contents>> In Examples 1 to 10 and Comparative Example 1, the yields of useful components and by-products in the pyrolysis gas recovered in the gas bag were determined in terms of carbon moles (C mol %) by the following method.

[0159] To the gas bag, 40 μL of cyclopentane (>98.0%, manufactured by Tokyo Chemical Industry Co., Ltd.) was added. The gas bag was heated to approximately 40°C to completely vaporize the contents, and then the gas bag was gently kneaded to mix the contents. The resulting contents were used as an analytical sample and analyzed by gas chromatography (GC) under the following GC analysis conditions. The proportion (C mol%) of each component in the pyrolysis gas in the gas bag was calculated from the ratio of the peak area of ​​cyclopentane to the peak area of ​​each component. The results are shown in Tables 1 and 2. [GC analysis conditions] Apparatus: Nexis GC-2030 (Shimadzu Corporation) Column: Rt-Alumina BOND (diameter: 0.32 mm, length: 30 m, Restek) Carrier gas type: Ar Carrier gas flow rate: 360 mL / min Injection temperature: 200°C Sample injection amount: 1 mL Split ratio: 1 / 200 Column temperature: After holding at 120°C for 9 minutes, the temperature was increased to 200°C at 10°C / min and held at 200°C for 30 minutes. Detector: Flame ionization detector (FID) Detector temperature: 200°C

[0160] <<Analysis of Cold Trap Contents>> In Examples 1 to 10 and Comparative Example 1, the yields of useful components and by-products in the thermally decomposed components recovered in the cold trap were determined in terms of carbon moles (C mol %) by the following method.

[0161] The contents were transferred to a sample vial, and 2 mL of o-dichlorobenzene (special grade, manufactured by Kanto Chemical Co., Ltd.) was added to the nearly emptied cold trap. The contents were then dissolved and transferred to the same sample vial. This process was repeated three times to rinse the cold trap. Cyclopentane (>98.0%, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the sample vial as an internal standard to prepare an analytical sample, which was analyzed by gas chromatography (GC) under the following GC analytical conditions. The proportion (C mol%) of each component in the thermal decomposition products in the cold trap was calculated from the ratio of the cyclopentane peak area to the peak area of ​​each component. The results are shown in Tables 1 and 2. [GC analysis conditions] Apparatus: Nexis GC-2030 (Shimadzu Corporation) Column: DB-1 (diameter: 0.25 mm, length: 30 m, Agilent Technology) Carrier gas type: He Carrier gas flow rate: 97 mL / min Injection temperature: 350°C Sample injection amount: 1 μL Split ratio: 1 / 50 Column temperature: The temperature rise program was set in the following order: 35°C (10 min) → temperature rise (5°C / min) → 350°C (10 min) Detector: Flame ionization detector (FID) Detector temperature: 350°C

[0162] <<Calculation of Calcination Weight Loss Rate>> In Examples 1 to 10 and Comparative Example 1, after the decomposition of the mixed plastics was completed, the filler layer was washed by flowing o-dichlorobenzene (special grade reagent, manufactured by Kanto Chemical Co., Ltd.) and acetone (special grade reagent, manufactured by Kanto Chemical Co., Ltd.) from a manual powder feeder. The tube was then left to stand for 10 minutes in a nitrogen gas atmosphere at a flow rate of 1,600 NmL / min to remove the o-dichlorobenzene and acetone from the filler layer. The quartz tube with the filler layer was then fired at 200°C for 30 minutes in a nitrogen gas atmosphere at a flow rate of 1,600 NmL / min. The mass X after firing in the nitrogen gas atmosphere was measured. Next, the quartz tube with the filler layer was fired at 600°C for 30 minutes in an air atmosphere at a flow rate of 500 NmL / min. The mass Y after air firing was measured. The firing weight loss rate was calculated from the measured values ​​based on the following formula. This value corresponds to the amount of coking. The firing loss rate was 0% by mass in all of Examples 1 to 10 and Comparative Example 1. Firing loss rate (% by mass) = (mass X - mass Y) / mass of input raw material M x 100

[0163] In Tables 1 and 2, the "yield of useful components" and "yield of by-products" refer to the ratio of the total number of moles of carbon atoms in each product listed in Tables 1 and 2 to the number of moles of carbon atoms (Cmol) contained in the mixed plastic.

[0164] In Tables 1 and 2, the "total yield of useful components" refers to the ratio of the total number of moles of carbon atoms contained in the olefins having 2 to 5 carbon atoms and useful aromatic hydrocarbons in the product to the number of moles of carbon atoms contained in the mixed plastic. "Useful components" refers to ethylene, propylene, olefins having 4 carbon atoms (trans-2-butene, 1-butene, 2-methylpropene, cis-2-butene, 1,3-butadiene, and isobutene), olefins having 5 carbon atoms (trans-2-pentene, 2-methyl-2-butene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, cis-2-pentene, 2-methyl-1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, and 1,3-cyclopentadiene), and useful aromatic hydrocarbons (benzene, toluene, ethylbenzene, three positional isomers of xylene (p-xylene, m-xylene, and o-xylene), and styrene).

[0165] In Tables 1 and 2, the "O / P ratio of 2 to 5 carbon atoms" was calculated based on the following formula 3: [Formula 3] O / P ratio of 2 to 5 carbon atoms = [Total content of 2 to 5 carbon atom olefins (C mol %)] / [Total content of 2 to 5 carbon atom paraffins (C mol %)]

[0166] In Examples 1 to 10 and Comparative Example 1, the calcination loss rate was 0% by mass, and therefore the "yield of useful components" and "yield of by-products" in Tables 1 and 2 were the same as the ratio of the total number of moles of carbon atoms in each product to the number of moles of carbon atoms (C mol) contained in the total mass of the products in Examples 1 to 10 and Comparative Example 1. The same was true for the "total yield of useful components" in Tables 1 and 2, which was the same as the ratio of the total number of moles of carbon atoms contained in olefins having 2 to 5 carbon atoms and useful aromatic hydrocarbons in the products to the number of moles of carbon atoms (C mol) contained in the total mass of the products in Examples 1 to 10 and Comparative Example 1.

[0167]

[0168]

[0169] As described above, the present disclosure has been described based on specific embodiments and examples, but these embodiments and examples are presented merely as examples, and the present disclosure is not limited to the above embodiments and examples. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, additions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims.

[0170] This international application claims priority based on Japanese Patent Application No. 2024-028236, filed on February 28, 2024, the entire contents of which are incorporated herein by reference.

[0171] 100: Apparatus 1: Fixed bed reaction section 2: Filler layer 2a: Filler 3: Mixed plastic supply section 3a: Raw material circulation section 3b: Raw material input section 4: Gas supply section 4a: Gas circulation section 4b: Pump 5: Heating section 6: Storage section 7: Cooling section 7a: Trap 7b: Cooling section 7c: Organic solvent 7d: Refrigerant 8: Gaseous product recovery section M: Raw material G: Inert gas

Claims

1. A method for producing at least one chemical product selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms, comprising: supplying a mixed plastic containing at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics, and a polyolefin, to a fixed bed reaction section having a filler layer filled with filler; and thermally decomposing the mixed plastic in the presence of an inert gas at a temperature of the filler layer of 820°C or less.

2. In the thermal decomposition, the volume of the filler layer is V (cm ３ ), and the volume of the filler in the filler layer is Vs (cm ３ 2. The method for producing a chemical product according to claim 1, wherein a residence time of the inert gas in the fixed bed reaction section, calculated by the ratio [(V−Vs) / v], is 2 seconds or less, where Vs is the flow rate of the inert gas and v is a flow rate of the inert gas (mL / min).

3. The method for producing a chemical product according to claim 1 or 2, wherein the temperature of the filler layer during the thermal decomposition is set to 770°C or less.

4. A method for producing a chemical product according to any one of claims 1 to 3, wherein in the thermal decomposition, the porosity of the filler layer is 20% or more and 80% or less.

5. The method for producing a chemical product according to any one of claims 1 to 4, wherein the polyolefin contains at least one selected from the group consisting of polyethylene and polypropylene.

6. The method for producing a chemical product according to any one of claims 1 to 5, wherein the aromatic-containing plastic contains polystyrene.

7. The method for producing a chemical product according to any one of claims 1 to 6, wherein the chlorine-containing plastic contains at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride, and chlorinated polyethylene.

8. In the pyrolysis, the volume of the filler layer is V (cm ３ ), and the volume of the filler in the filler layer is Vs (cm ３ 8. The method for producing a chemical product according to claim 1, wherein a residence time of the inert gas in the fixed bed reaction section, calculated by the ratio [(V−Vs) / v], is 0.1 seconds or more, where Vs is the flow rate of the inert gas and v is a flow rate of the inert gas (mL / min).

9. The method for producing a chemical product according to any one of claims 1 to 8, wherein the temperature of the filler layer is set to 500°C or higher during the thermal decomposition.

10. The method for producing a chemical product according to any one of claims 1 to 9, wherein the aromatic hydrocarbon is at least one selected from the group consisting of benzene, toluene, xylene, ethylbenzene, and styrene.

11. An apparatus for producing at least one chemical product selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons, comprising: a fixed bed reaction section having a filler layer filled with filler; a mixed plastic supply section that supplies mixed plastics containing polyolefins and at least one selected from the group consisting of aromatic plastics and chlorine-containing plastics to the fixed bed reaction section; a gas supply section that supplies inert gas to the fixed bed reaction section; and a heating section that heats the filler layer to a temperature of 820°C or less.

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