Method and apparatus for manufacturing chemicals

Abstract

A method for producing at least one chemical selected from the group consisting of olefins having a carbon number of 2 to 5 and aromatic hydrocarbons, the method comprising: feeding mixed plastics to a fixed bed reaction section having a filler layer filled with a filler, wherein the mixed plastics contain at least one selected from the group consisting of aromatic-containing plastics and chlorine-containing plastics, and polyolefins; and setting the temperature of the filler layer to 820°C or lower, and thermally decomposing the mixed plastics in the presence of an inactive gas.

Description

Technical Field

[0001] This disclosure relates to a method and apparatus for manufacturing a chemical. Background Technology

[0002] Fixed-bed reactors are widely used due to their simple structure and ease of operation. They are also used in processes known as chemical recycling, where plastics are thermally decomposed and the monomers and other basic chemicals that constitute the raw plastic are removed.

[0003] For example, Patent Document 1 discloses a waste plastic treatment method that uses a fixed-bed reactor filled with a gallium silicate catalyst to recover catalytic reaction products by gasifying waste plastic through thermal decomposition and contacting the resulting thermal decomposition gas with the catalyst. Specifically, it discloses that granular gallium silicate is used as a fixed bed, and molten polyethylene is supplied separately and continuously. During thermal decomposition and gasification at 425–525°C, the polyethylene is simultaneously contacted with the gallium silicate to obtain benzene, toluene, and xylene.

[0004] Furthermore, Patent Document 2 discloses a method for manufacturing olefins, which includes: a step of heating a polyolefin-based plastic to obtain a decomposition product; and a step of contacting the obtained decomposition product with an MFI-type zeolite containing 0.10% to 0.30% by mass of sodium atoms to obtain a catalytic decomposition product containing olefins. Specifically, it discloses that an MFI-type zeolite containing sodium atoms is filled into a downstream reaction tube, and polyethylene, polypropylene, or a mixture thereof is passed from an upstream reaction tube to a downstream reaction tube, and while contacting it with the MFI-type zeolite containing sodium atoms, it is thermally decomposed at 525°C to obtain an olefin with 2 to 3 carbon atoms.

[0005] Furthermore, Patent Document 3 discloses the thermal decomposition of various plastics such as polyethylene, polypropylene, and polystyrene at 500°C in an intermittent fixed-bed reactor filled with a catalyst, yielding gaseous products composed of C1-C3 olefins and alkanes, as well as liquid products (mainly C1-C3 olefins and alkanes). 4+ ).

[0006] On the other hand, in continuous reaction devices that use mixed plastics containing aromatic plastics such as polystyrene, chlorinated plastics such as polyvinyl chloride, and polyolefins as raw materials to obtain basic chemicals in a single stage without intermediate products such as thermal decomposition oils, fluidized bed reactors are generally used. For example, Patent Document 4 discloses a method for producing olefins and aromatic compounds from raw materials by introducing a hydrocarbon feedstock such as plastics and a catalyst composition into a reactor, in which a packed bed reactor, i.e., a fixed bed reactor, can be used. However, as a specific example, only an example using a fluidized bed reactor is disclosed.

[0007] <Prior art documents>

[0008] <Patent Documents>

[0009] Patent Document 1: Japanese Patent Application Publication No. 2001-316517

[0010] Patent Document 2: International Publication No. 2021 / 166854

[0011] Patent Document 3: Japanese Patent Publication No. 2022-533116

[0012] Patent Document 4: Japanese Patent Publication No. 2016-513147 Summary of the Invention

[0013] <Problem to be solved by this invention>

[0014] However, the methods described in existing technical literature cannot obtain useful components such as lower olefins in high yields using mixed plastics as raw materials.

[0015] The purpose of this disclosure is to provide a method for manufacturing chemicals that can obtain useful components in high yield and with good efficiency.

[0016] <Methods for solving problems>

[0017] As a means to solve the above-mentioned problems, it is described below. That is,

[0018] <1> A method for manufacturing a chemical, characterized in that it is a method for manufacturing at least one chemical selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons.

[0019] The manufacturing method includes:

[0020] A mixed plastic is fed into a fixed-bed reaction section having a filler-filled layer, wherein the mixed plastic comprises: at least one selected from the group consisting of aromatic plastics and chlorinated plastics, and a polyolefin; and

[0021] The temperature of the filler layer is set below 820°C, and the mixed plastic is thermally decomposed in the presence of an inactive gas.

[0022] <2> according to <1> The method for manufacturing the chemical described herein, wherein, in the thermal decomposition, the volume of the filler layer is set as V (cm²). 3 The volume of the filler in the filler layer is set as Vs (cm). 3 When the flow rate of the inactive gas is set to v (mL / min), the residence time of the inactive gas in the fixed bed reaction section, calculated by the ratio [(V-Vs) / v], is less than 2 seconds.

[0023] <3> according to <1> or <2> The method for manufacturing the chemical, wherein, in the thermal decomposition, the temperature of the filler layer is set to below 770°C.

[0024] <4> according to <1> to <3> The method for manufacturing the chemical described in any one of the following statements, wherein, during the thermal decomposition, the porosity of the filler layer is 20% or more and 80% or less.

[0025] <5> according to <1> to <4> The method for manufacturing the chemical according to any one of the following methods, wherein the polyolefin contains at least one selected from the group consisting of polyethylene and polypropylene.

[0026] <6> according to <1> to <5> The method for manufacturing the chemical described in any one of the following statements, wherein the aromatic plastic contains polystyrene.

[0027] <7> according to <1> to <6> The method for manufacturing the chemical described in any one of the following statements, wherein the chlorinated plastic contains at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride, and chlorinated polyethylene.

[0028] <8> according to <1> to <7> The method for manufacturing the chemical described in any one of the above statements, wherein, in the thermal decomposition, the volume of the filler layer is set as V (cm²). 3 The volume of the filler in the filler layer is set as Vs (cm). 3 When the flow rate of the inactive gas is set to v (mL / min), the residence time of the inactive gas in the fixed bed reaction section, calculated by the ratio [(V-Vs) / v], is 0.1 seconds or more.

[0029] <9> according to <1> to <8> The method for manufacturing the chemical described in any one of the following statements, wherein, during the thermal decomposition, the temperature of the filler layer is set to 500°C or higher.

[0030] <10> according to <1> to <9> The method for manufacturing the chemical described in any one of the following statements, wherein the aromatic hydrocarbon is at least one selected from the group consisting of benzene, toluene, xylene, ethylbenzene and styrene.

[0031] <11> An apparatus characterized in that it is an apparatus for manufacturing at least one chemical selected from the group consisting of olefins having two to five carbon atoms and aromatic hydrocarbons.

[0032] The device has:

[0033] A fixed-bed reaction section having a packing layer filled with packing material;

[0034] A mixed plastic supply unit supplies mixed plastic to the fixed-bed reaction unit, wherein the mixed plastic contains: polyolefin, and at least one selected from the group consisting of aromatic plastics and chlorinated plastics;

[0035] A gas supply unit that supplies inactive gas to the fixed-bed reaction unit; and

[0036] The heating section heats the temperature of the filler layer to below 820°C.

[0037] <12> according to <11> In the aforementioned apparatus, the volume of the filler layer is defined as V (cm²). 3 The volume of the filler in the filler layer is set as Vs (cm). 3 When the flow rate of the inactive gas is set to v (mL / min), the gas supply unit supplies the inactive gas in such a way that the residence time of the inactive gas in the fixed bed reaction unit is less than 2 seconds, as determined by the ratio [(V-Vs) / v].

[0038] <13> according to <11> or <12> In the aforementioned apparatus, the heating unit heats the temperature of the filler layer to below 770°C.

[0039] <14> according to <11> to <13> The apparatus according to any one of the following methods, wherein the porosity of the filler layer is more than 20% and less than 80%.

[0040] <15> according to <11> to <14> The apparatus of any one of the following, wherein the polyolefin comprises at least one selected from the group consisting of polyethylene and polypropylene.

[0041] <16> according to <11> to <15> The apparatus according to any one of the following methods, wherein the aromatic plastic contains polystyrene.

[0042] <17> according to <11> to <16> The apparatus according to any one of the following methods, wherein the chlorinated plastic contains at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride and chlorinated polyethylene.

[0043] <18> according to <11> to <17> In any one of the apparatuses, the volume of the filler layer is set as V (cm²). 3 The volume of the filler in the filler layer is set as Vs (cm). 3 When the flow rate of the inactive gas is set to v (mL / min), the gas supply unit supplies the inactive gas in such a way that the residence time of the inactive gas in the fixed bed reaction unit is 0.1 seconds or more, as determined by the ratio [(V-Vs) / v].

[0044] <19> according to <11> to <18> In any one of the apparatuses, the heating unit heats the temperature of the filler layer to 500°C or higher.

[0045] <The Effects of the Invention>

[0046] According to embodiments of this disclosure, a method for manufacturing chemicals that can obtain useful components in high yield and with good efficiency can be provided. Attached Figure Description

[0047] Figure 1 This is a schematic cross-sectional view illustrating an example of the apparatus of this disclosure.

[0048] Figure 2 This is a schematic cross-sectional view illustrating another example of the apparatus of this disclosure. Detailed Implementation

[0049] The embodiments of this disclosure are described in detail below. It should be noted that the embodiments are not limited to the following description and may be appropriately modified without departing from the spirit of this disclosure. Furthermore, in this specification, unless otherwise stated, the "~" indicating a numerical range means that the values ​​described before and after it are included as lower and upper limits.

[0050] (Methods for manufacturing chemicals)

[0051] The method for manufacturing the chemical disclosed herein is a method for manufacturing at least one chemical selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons, comprising: feeding a mixed plastic containing at least one of the group consisting of aromatic plastics and chlorinated plastics and a polyolefin into a fixed-bed reaction section having a filler layer; and setting the temperature of the filler layer to below 820°C and thermally decomposing the mixed plastic in the presence of an inactive gas. The method for manufacturing the chemical disclosed herein may further include other treatments as needed.

[0052] 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 a mixture of plastics containing at least one of the groups selected from aromatic plastics and chlorinated plastics and polyolefins to produce useful components in high yield.

[0053] Compared to polyolefins, aromatic and chlorinated plastics typically have lower decomposition temperatures. Therefore, in blends of these plastics, when heated to the decomposition temperature of polyolefins, both aromatic and chlorinated plastics will carbonize. As a result, in addition to the problem of reduced yields of useful components due to the inability to obtain them from the aromatic and chlorinated plastics, there is also a concern about blockage of the feedstock and decomposition product flow paths when using fixed-bed reactors.

[0054] On the other hand, fixed-bed reactors are simple in construction and easy to operate. Therefore, if a large amount of carbides are not generated from the mixed plastics in a one-stage reaction, and useful components can be obtained in high yield, a fixed-bed reactor is desirable. Although Patent Document 4 discloses that a fixed-bed reactor can be used in the decomposition of mixed plastics, it does not describe the specific reaction conditions when using a fixed-bed reactor.

[0055] Through in-depth research, the inventors have discovered a method for manufacturing a chemical that can produce at least one chemical selected from the group consisting of olefins with 2 to 5 carbon atoms and aromatic hydrocarbons in high yield and with good efficiency from a mixed plastic containing at least one of aromatic plastics and chlorinated plastics and polyolefins.

[0056] <Chemicals>

[0057] The chemical manufactured by the method of manufacturing the chemical disclosed herein is at least one of the group consisting of olefins having two to five carbon atoms and aromatic hydrocarbons. Therefore, in this disclosure, "useful ingredient" means at least one of the group consisting of olefins having two to five carbon atoms and aromatic hydrocarbons.

[0058] It should be noted that, in this disclosure, alkenes having 2 to 5 carbon atoms are sometimes referred to as "lower alkenes". Additionally, in this disclosure, aromatic hydrocarbons are sometimes referred to as "useful aromatic hydrocarbons".

[0059] <<Alkenes with 2 to 5 carbon atoms>>

[0060] As an olefin having 2 to 5 carbon atoms, it is preferably at least one selected from the group consisting of chain olefins having 2 to 5 carbon atoms and dienes having 2 to 5 carbon atoms, and more preferably chain olefins having 2 to 5 carbon atoms.

[0061] Examples of olefins with two carbon atoms include ethylene.

[0062] Examples of olefins with three carbon atoms include propylene.

[0063] Examples of olefins with four carbon atoms include trans-2-butene, 1-butene, 2-methylpropene, cis-2-butene, 1,3-butadiene, and isobutene.

[0064] Examples of olefins with 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.

[0065] The method for manufacturing the chemicals disclosed herein has the advantage of high yields of ethylene and propylene. The total content (Cmol%) of ethylene and propylene in the chemicals is not particularly limited and can be appropriately selected according to the purpose, but is preferably 35 mol% or more and 70 mol% or less relative to the total carbon moles (Cmol) of the chemicals, more preferably 36 mol% or more and 45 mol% or less.

[0066] It should be noted that in this disclosure, the content based on the number of carbon moles is expressed as "Cmol%".

[0067] The total content (Cmol%) of olefins having 2 to 5 carbons in the chemical is not particularly limited and can be appropriately selected according to the purpose, but is preferably 40 mol% or more and 90 mol% or less relative to the total number of carbon moles (Cmol) of the hydrocarbon-containing composition, more preferably 42 mol% or more and 70 mol% or less, and even more preferably 45 mol% or more and 60 mol% or less.

[0068] Olefins with 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 suitable for various applications such as plastic bags, cling film, straws, medical devices, appliance housings, erasers, hoses, tires, tubes, CD cases, food trays, food containers, plastic bottles, and fibers.

[0069] <<Aromatic Hydrocarbons>>

[0070] There are no particular restrictions on the aromatic hydrocarbons, but the three positional isomers of benzene, toluene, ethylbenzene, and xylene (p-xylene, m-xylene, and o-xylene) and styrene are preferred, and the three positional isomers of benzene, toluene, and xylene are more preferred.

[0071] There is no particular limitation on the total content (Cmol%) of aromatic hydrocarbons in the chemical product, and it can be appropriately selected according to the purpose. However, it is preferably 20 mol% or more and 50 mol% or less relative to the total number of carbon moles (Cmol) of the hydrocarbon-containing composition, and more preferably 22 mol% or more and 30 mol% or less.

[0072] It should be noted that in this disclosure, benzene, toluene, ethylbenzene, the three positional isomers of xylene (p-xylene, m-xylene, and o-xylene) and styrene are sometimes referred to as "useful aromatic hydrocarbons".

[0073] <<Byproducts>>

[0074] Chemicals obtained by the methods of manufacturing chemicals disclosed herein sometimes contain byproducts. Examples of byproducts include, for instance, alkanes, carbon, and hydrogen.

[0075] There are no particular limitations on the alkanes; examples include aliphatic saturated hydrocarbons having 1 to 5 carbon atoms, with aliphatic saturated hydrocarbons having 2 to 5 carbon atoms being preferred. Examples of aliphatic saturated hydrocarbons having 1 to 5 carbon atoms include chain-like aliphatic saturated hydrocarbons having 1 to 5 carbon atoms.

[0076] Specific examples of alkanes include methane, ethane, propane, isobutane, n-butane, and n-pentane. Among these, methane has a relatively low selectivity in the method for manufacturing the chemicals disclosed herein.

[0077] The lower the methane content (Cmol%) in the chemical, the better. More preferably, it is 12 mol% or less relative to the total carbon moles (Cmol) of the chemical, further preferably 10 mol% or less, and particularly preferably 9 mol% or less. As a lower limit value for the methane content in the chemical, it is preferably 0.1 mol% or more relative to the total carbon moles (Cmol) of the chemical.

[0078] The total percentage (Cmol%) of alkanes 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 (Cmol%) of the hydrocarbon-containing composition. The lower limit of the total percentage (Cmol%) of alkanes 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 (Cmol%) of the hydrocarbon-containing composition.

[0079] -O / P ratio-

[0080] In this disclosure, since the amount of alkanes as byproducts is relatively small, it can be evaluated by calculating the ratio of the total content of olefins (Cmol%) to the total content of alkanes (Cmol%) in the chemical, i.e., the ratio [total content of olefins (Cmol%) / total content of alkanes (Cmol%)] (hereinafter, sometimes referred to as the "O / P ratio"). In the method for manufacturing the chemical disclosed herein, the ratio [total content of olefins (Cmol%) / total content of alkanes (Cmol%)] is evaluated using the ratio [total content of olefins having 2 to 5 carbons (Cmol%) / total content of alkanes having 2 to 5 carbons (Cmol%)].

[0081] There are no particular restrictions on the O / P ratio for carbon numbers 2 to 5, and it can be appropriately selected according to the purpose, but it is preferably 5 or higher, and more preferably 10 or higher. Since the higher the O / P ratio, the better, there are no particular restrictions on the upper limit of the O / P ratio for carbon numbers 2 to 5, but it is preferably 50 or lower, and more preferably 20 or lower.

[0082] The content of useful components in the chemicals and the O / P ratio of carbon 2 to carbon 5 can be determined by analyzing the products, i.e. gaseous products and liquid substances, obtained by the manufacturing method of the chemicals disclosed herein using a gas chromatography (GC) apparatus equipped with a flame ionization detector.

[0083] When analyzing the gaseous products, analysis is performed using gas chromatography (GC) equipped with a flame ionization detector under the analytical conditions described in the examples. The internal standard method is used to quantify each component based on the ratio of its peak area to that of the internal standard. It should be noted that there are no particular limitations on the internal standard, as long as it is stable under analytical conditions and easily separated from the analyte; cyclopentane is an example.

[0084] Furthermore, when analyzing the liquid substances that are the products, analysis is performed by gas chromatography (GC) equipped with a flame ionization detector under the analytical conditions described in the examples. The internal standard method is used to quantify each component based on the ratio of its peak area to that of the internal standard. It should be noted that there are no particular limitations on the internal standard, as long as it is stable under the analytical conditions and easily separated from the analyte; cyclopentane is an example.

[0085] In addition, the content of by-products such as coke and other residues contained in the product can be calculated by air combustion of the packing layer inside the fixed bed reaction section, or by removing the packing material constituting the packing layer from the fixed bed reaction section and air combustion, based on the weight change before and after air sintering.

[0086] (Supply to the fixed-bed reaction section)

[0087] The supply to the fixed-bed reaction section involves supplying a mixed plastic containing at least one of the group consisting of aromatic plastics and chlorinated plastics, as well as a polyolefin, to the fixed-bed reaction section having a filler layer filled with filler.

[0088] There are no particular limitations on the method of supplying the mixed plastic to the fixed-bed reaction section; it can be supplied intermittently or continuously. Among these methods, intermittent supply is preferred because it can reduce temperature changes in the packing layer.

[0089] When the mixed plastic is intermittently supplied to the fixed-bed reaction section, there are no particular restrictions on the supply time, non-supply time and interval of the mixed plastic.

[0090] When the mixed plastic is intermittently supplied to the fixed-bed reaction section, there is no particular limitation on the amount of mixed plastic supplied each time. However, when the mass of the filler in the packing layer is defined as "Wf" (g) and the amount of mixed plastic supplied each time is defined as "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 in the range of 0.001 to 0.05, the temperature change when supplying the mixed plastic to the packing layer is small, and the useful components can be obtained efficiently and in high yield.

[0091] When the mixed plastic is intermittently supplied to the fixed bed reaction section, from the viewpoint of preventing the temperature of the packing layer from dropping excessively, it is preferable to feed the mixed plastic a second time after the temperature of the packing layer, which was lowered due to the previous feeding, has recovered and reached 680°C or higher.

[0092] When the mixed plastic is continuously supplied to the fixed-bed reaction section, there is no particular limitation on the amount of mixed plastic supplied. However, when the mass of the filler in the packing layer is defined as "Wf" (g) and the amount of mixed plastic supplied per minute is defined as "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 in the range of 0.00025 to 0.0125, the temperature change when supplying the mixed plastic to the packing layer is small, and the useful components can be obtained efficiently and in high yield.

[0093] <Mixed Plastics>

[0094] The blended plastic contains at least one selected from the group consisting of aromatic plastics and chlorinated plastics, and a polyolefin. Further, as needed, the blended plastic may also contain other components.

[0095] <<Contains aromatic plastics>>

[0096] Aromatic plastics refer to plastics with an aromatic backbone. There are no particular limitations on aromatic plastics; they can be appropriately selected from plastics widely used in beverage and food containers, packaging materials, molded products, and films, depending on the purpose. Examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), acrylonitrile-butadiene-styrene copolymer, polycarbonate (PC), and polystyrene (PS). These can contain one or more of these compounds. Among them, polystyrene (PS) is preferred.

[0097] Chlorinated Plastics

[0098] There are no particular restrictions on chlorinated plastics, and they can be appropriately selected according to the purpose, but it is preferred that they contain at least one of the following: polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), and chlorinated polyethylene (CPE), which are widely used in containers, packaging materials, molded articles, films, etc. for beverages and food.

[0099] The content of at least one of the aromatic and chlorinated plastics in the mixed plastic is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10% by mass or more and 50% by mass or less relative to the total mass of the mixed plastic, more preferably 15% by mass or more and 40% by mass or less. If the content of at least one of the aromatic and chlorinated plastics in the mixed plastic is 10% by mass or more and 50% by mass or less, at least one chemical selected from the group consisting of olefins with 2 to 5 carbon atoms and aromatic hydrocarbons can be obtained in high yield and with good efficiency.

[0100] <<Polyolefins>>

[0101] There are no particular restrictions on the polyolefin, and it can be appropriately selected according to the purpose, but it is preferred to contain at least one of polyethylene (PE) and polypropylene (PP), which are widely used in containers, packaging materials, molded articles, films and the like for beverages and food.

[0102] There is no particular limitation on the content of polyolefins in the mixed plastic, and it can be appropriately selected according to the purpose. However, relative to the total mass of the mixed plastic, it is preferably 50% by mass or more and 90% by mass or less, more preferably 60% by mass or more and 85% by mass or less. If the content of polyolefins in the mixed plastic is 50% by mass or more and 90% by mass or less, then in addition to using readily available mixed plastics without sorting, at least one chemical selected from the group consisting of olefins with 2 to 5 carbon atoms and aromatic hydrocarbons can be obtained in high yield and with good efficiency.

[0103] <<Other Ingredients>>

[0104] There are no particular restrictions on other components contained in mixed plastics, and they can be appropriately selected according to the purpose. For example, other plastics besides at least one selected from the group consisting of aromatic plastics and chlorinated plastics, as well as polyolefins, can be included; materials commonly contained in waste plastics, such as paper and metals, etc. These can be contained individually or in two or more forms.

[0105] There are no particular restrictions on other plastics; they can be selected appropriately depending on the purpose. Examples include polyamide, polyurethane, and polymethyl methacrylate.

[0106] There are no particular restrictions on the content of other components in the mixed plastic, and they can be appropriately selected according to the type of mixed plastic used. However, from the viewpoint of the yield of at least one chemical selected from the group consisting of olefins with 2 to 5 carbon atoms and aromatic hydrocarbons, it is preferable to be less than 30% by mass, more preferably 25% by mass or less, and even more preferably 20% by mass or less, relative to the total mass of the mixed plastic.

[0107] From the perspective of reducing environmental impact, blended plastics preferably contain waste plastics. When the blended plastics are waste plastics, there are no particular restrictions on the composition and composition ratio, and they can be appropriately selected according to the purpose, but it is preferred that PE be 20% to 40% by mass, PP be 20% to 40% by mass, and PS be 10% to 30% by mass.

[0108] The structure and content of each component in a mixed plastic can be determined by analysis methods such as gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), liquid chromatography-mass spectrometry (LC-MS), thermal pyrolysis gas chromatography-mass spectrometry (PyGC-MS), and matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOFMS).

[0109] The state of the mixed plastic supplied to the fixed-bed reactor is not particularly limited; for example, it can be crystalline, glassy, ​​rubbery, liquid, or undecomposed. Alternatively, the mixed plastic can also be in the form of decomposed material. From the viewpoint of easy control of the supply amount or obtaining the hydrocarbon composition from waste plastic in fewer processes, rubbery or liquid mixed plastics are preferred, and undecomposed plastics are more preferred.

[0110] When the mixed plastic is in a crystalline or glassy state, there are no particular restrictions on its form. For example, examples include crushed mixed plastic, granules of crushed mixed plastic, and fragments of crushed mixed plastic.

[0111] There are no particular restrictions on the pulverized material used for mixing plastics; it can be appropriately selected according to the purpose, for example, in powder or flake form.

[0112] Rubber-state or liquid mixed plastics refer to plastics that are fluid at temperatures above the melting point of the mixed plastics but below the thermal decomposition temperature of the mixed plastics. Rubber-state or liquid mixed plastics are also called "molten mixed plastics".

[0113] Decomposition products of blended plastics are materials obtained by reducing the molecular weight of blended plastics, but with a molecular weight greater than that of the chemicals that are the final products, and are usually obtained by heating the blended plastics at a temperature above 300°C and below 500°C.

[0114] The molecular weight of rubbery or liquid mixed plastics remains unchanged compared to that of crystalline or glassy mixed plastics of the same composition. Therefore, mixed plastics and their decomposition products can be distinguished by molecular weight. Since the melting point decreases as the molecular weight decreases due to decomposition, it can be determined in practical applications by the melting temperature. The melting temperature is determined according to the method specified in JIS K7121-2012.

[0115] There are no particular restrictions on the melting point of the mixed plastics, and it can be appropriately selected according to the raw materials used, but it is preferred to be 80℃~200℃, and more preferably 90℃~190℃.

[0116] These various forms of hybrid plastics can be hybrid plastics that have been separated from the chemical manufacturing method of one embodiment, or hybrid plastics that have undergone other treatments described later.

[0117] Fixed-bed reaction section

[0118] The fixed-bed reaction section has a packing layer filled with packing material, and may also have other layers as needed.

[0119] <<Packaging Layer>>

[0120] The packing layer is formed by filling the reaction section with packing material. The packing layer forms a fixed bed in the fixed-bed reaction section.

[0121] To ensure the flow path of the mixed plastic and inactive gas during thermal decomposition, the filler layer preferably has a certain degree of porosity. The porosity φ of the filler layer is not particularly limited and can be appropriately set according to the properties of the mixed plastic used and the conditions during thermal decomposition. However, from the viewpoint of fully ensuring the flow path of the mixed plastic and inactive gas, and fully ensuring contact between the filler and the mixed plastic, it is preferably 20% or more and 80% or less, more preferably 30% or more and 70% or less, and even more preferably 40% or more and 60% or less.

[0122] In this disclosure, "void ratio φ" is the proportion of voids in the filler layer, which is calculated according to Equation 1 and Equation 2 below.

[0123] [Formula 1]

[0124] Porosity φ (%) = (1 - Vs / V) × 100

[0125] (In Equation 1, "Vs" represents the volume of the packing material (cm³) calculated using Equation 2 below.) 3 “V” indicates the volume of the filler layer (cm³). 3 It should be noted that the volume of the packing layer refers to the volume of the packing section in the fixed-bed reaction section.

[0126] [Equation 2]

[0127] Vs=Wf / TD

[0128] (In Equation 2, "Wf" represents the mass (g) of the filler material packed into the packing layer, and "TD" represents the true density (g / cm³) of the filler material.) 3 ). )

[0129] There are no particular restrictions on the shape and structure of the filler layer, and it can be appropriately selected according to the purpose. However, from the viewpoint of enabling the smooth flow of the mixed plastic and the generated chemicals and ensuring sufficient contact time between the mixed plastic and the filler, it is preferable that the length of the mixed plastic in the flow direction is longer than the inner diameter of the fixed bed reaction section in the direction orthogonal to the flow direction.

[0130] -filler-

[0131] Packing material is used to maintain the temperature of the reaction system during thermal decomposition at a certain level.

[0132] As a filler, there are no particular restrictions, and it can be appropriately selected according to the purpose. However, it is preferred to use a material that is stable within the temperature range of thermal decomposition during thermal decomposition, which will not be reduced by byproducts such as carbon and hydrogen generated during the thermal decomposition of the mixed plastic, and will not react with inactive gases.

[0133] Specific examples of fillers include zirconium oxide, yttrium-stabilized zirconium oxide, calcium oxide-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, forsterite, cordierite, etc. Additionally, fillers can be those for surface passivation, improved flowability of mixed plastics, etc., after surface treatment of the aforementioned materials. One type can be used alone, or two or more types can be used in combination. Preferably, one or more of silicon carbide, aluminum oxide, silicon oxide, or surface-treated materials thereof are used as fillers. More preferably, one or more types selected from the group consisting of silicon carbide and aluminum oxide are used, possessing a non-reactive surface that does not catalyze the oxidative decomposition reaction of water vapor and hydrocarbons or the carbon precipitation reaction, and having good thermal conductivity.

[0134] There are no particular limitations on the filler used after surface treatment, and it can be appropriately selected according to the purpose. For example, fillers with an oxide film on the surface and fillers with a carbon film on the surface can be listed. Among them, fillers with a carbon film on the surface are preferred as fillers after surface treatment from the viewpoint that they are less likely to generate active sites due to surface treatment and can prevent side reactions.

[0135] There are no particular restrictions on the methods for surface treatment of fillers, and appropriate methods can be selected from those known to the public.

[0136] For example, in the case of making fillers with an oxide film on the surface, a method can be cited to form an oxide film on the surface of the filler by oxidation.

[0137] Furthermore, when manufacturing fillers with a carbon film on their surface, a method can be cited where an organic compound is attached to the surface of the filler, and then sintered in the presence of an inactive gas to form a carbon film. From the viewpoint of easily forming a uniform and homogeneous carbon film, hydroxycarboxylic acids are preferably used as the organic compound when manufacturing fillers with a carbon film on their surface.

[0138] As hydroxycarboxylic acids, there are no particular restrictions, and they can be appropriately selected according to the purpose. Examples include malic acid, citric acid, tartaric acid, gallic acid, and salicylic acid. These can be used alone or in combination with two or more.

[0139] The structure of the surface-treated filler can be confirmed by observation using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), micro Raman spectroscopy, etc.

[0140] There is no particular limitation on the coverage rate of the carbon film over the filler in fillers with a carbon film on the surface, and it can be appropriately selected according to the purpose. However, the mass ratio of carbon forming the carbon film to the filler [carbon / filler] is preferably 0.0001 or more and 0.5 or less, more preferably 0.001 or more and 0.1 or less, even more preferably 0.001 or more and 0.1 or less, and particularly preferably 0.002 or more and 0.08 or less. When the mass ratio [carbon / filler] is 0.0001 or more and 0.5 or less, it can effectively assist the contact between fillers and efficiently thermally decompose the mixed plastic within the thermal decomposition temperature range during thermal decomposition. It should be noted that the mass ratio [carbon / filler] is a mass ratio calculated based on the mass of the organic compound that serves as the carbon source in the filler with a carbon film on the surface and the mass of the filler. Therefore, the coverage of the filler by the carbon film can be complete or partial. Therefore, the carbon film includes not only layered forms but also those that appear as islands when observed on the surface.

[0141] In fillers with a carbon film on their surface, the coverage of the filler by the carbon film can be confirmed by methods such as calculating based on the amount of feed or analyzing the weight change of the carbon film based on the weight change of thermogravimetric differential thermal analysis (TG-DTA).

[0142] There are no particular restrictions on the size of the packing material, and it can be appropriately selected according to the purpose. However, the preferred size, based on the nominal pore size, is 90 μm to 125 mm, and more preferably 125 μm to 90 mm. It should be noted that the size of the packing material is determined based on JIS Z 8801-1:2019.

[0143] There are no particular restrictions on the shape and structure of the filler, and it can be appropriately selected according to the purpose. However, the shape of the filler is preferably one in which the molten mixed plastic is difficult to remain on the filler, preferably spherical, and more preferably perfectly spherical.

[0144] (Thermal decomposition)

[0145] Thermal decomposition involves setting the temperature of the filler layer below 820°C and thermally decomposing the mixed plastic in the presence of an inactive gas. Thermal decomposition yields at least one chemical selected from the group consisting of olefins with 2 to 5 carbon atoms and aromatic hydrocarbons.

[0146] In thermal decomposition, there are no particular restrictions on the temperature of the filler layer as long as it is below 820°C, but it is preferably below 770°C. If the temperature of the filler layer is below 820°C, the useful components can be obtained in high yield and with good efficiency. In addition, when the temperature of the filler layer is below 770°C, the formation of methane, a byproduct generated from the decomposition of mixed plastics and which is difficult to use as a basic chemical, can be suppressed.

[0147] In thermal decomposition, there is no particular limitation on the lower limit of the temperature of the filler layer, as long as it can decompose the mixed plastic. It can be appropriately selected according to the purpose, but it is preferred to be 500°C or higher, more preferably 580°C or higher, and even more preferably 650°C or higher. In thermal decomposition, if the temperature of the filler layer is 500°C or higher, the useful components can be obtained in high yield and with good efficiency.

[0148] During thermal decomposition, the upper and lower limits of the temperature of the filler layer can be appropriately combined, but preferably above 500°C and below 820°C, more preferably above 580°C and below 820°C, and even more preferably above 650°C and below 770°C.

[0149] <Inactive Gases>

[0150] There are no particular restrictions on the type of inactive gas, but it is preferred to be an inactive gas that is stable within the temperature range of thermal decomposition during thermal decomposition.

[0151] Examples of inert gases include nitrogen, water vapor, carbon dioxide, and rare gases. They can be used individually or in combination of two or more. Among these, since they are inexpensive, it is preferable to choose one or more gases from the group consisting of nitrogen and water vapor, with nitrogen being more preferred.

[0152] In thermal decomposition, the flow rate of the inactive gas is not particularly limited and can be appropriately selected according to the purpose, but the volume of the packing layer is set as V (cm³). 3 Let the volume of the packing in the packing layer be Vs (cm). 3 When the flow rate of the inactive gas is set to v (mL / min), it is preferable to have a flow rate at which the residence time t of the inactive gas in the fixed-bed reaction section is 2.5 seconds or less, as determined by the ratio [(V-Vs) / v], and more preferably a flow rate of 2 seconds or less. When the flow rate of the inactive gas is such that the residence time t is 2.5 seconds or less, the contact time between the mixed plastic and the packing material can be sufficiently ensured, and side reactions can be suppressed. Therefore, the useful components can be obtained with high yield and good efficiency. Vs is calculated using Equation 2.

[0153] There is no particular limitation on the lower limit of the inactive gas flow rate, but from the viewpoint of ensuring sufficient contact time between the mixed plastic and the packing and obtaining useful components with high yield and good efficiency, it is preferable that the residence time t of the inactive gas in the fixed bed reaction section is 0.1 seconds or more, more preferably 0.5 seconds or more, and even more preferably 1 second or more.

[0154] While it is possible to appropriately combine the upper and lower limits of the inactive gas flow rate, it is preferable that the residence time t of the inactive gas in the fixed bed reaction section is 0.1 seconds or more and 4.0 seconds or less, more preferably 0.5 seconds or more and 2.5 seconds or less, and even more preferably 1 second or more and 2 seconds or less.

[0155] (Other processing)

[0156] The method for manufacturing the chemicals disclosed herein may, as needed, include other treatments besides feeding to a fixed-bed reaction section and thermal decomposition.

[0157] There are no particular restrictions on other treatments, and appropriate options can be selected depending on the purpose. Examples include pretreatment of mixed plastics, recycling of chemicals obtained through thermal decomposition, and separation of chemicals.

[0158] <<Preprocessing>>

[0159] In the pretreatment process, the mixed plastics are pretreated before being fed into the supply system. Pretreatment transforms the mixed plastics into a form or state that facilitates decomposition, enabling more efficient decomposition of the mixed plastics.

[0160] Examples of pretreatment include crushing of mixed plastics, granulation (fragmentation) of crushed mixed plastics, and melting of mixed plastics.

[0161] The melt treatment of mixed plastics is preferably carried out at a temperature below 300°C.

[0162] There are no particular restrictions on the pulverized material used for mixing plastics; it can be selected appropriately according to the purpose. For example, powder or flakes can be used.

[0163] There are no particular limitations on the method for obtaining the pulverized mixed plastic, and appropriate methods can be selected from those already known. For example, a method of pulverizing the mixed plastic with a pulverizer to obtain powder or small pieces can be cited.

[0164] Furthermore, there are no particular limitations on the method for granulating (fragmenting) the pulverized material, and it is possible to appropriately select from existing known methods. For example, a method can be given where the pulverized material is melt-extruded and then cut into linear shapes to obtain the fragmented raw material.

[0165] The mixed plastics can also be supplied in a molten state. There are no particular limitations on the method of molten mixing of plastics, and appropriate methods can be selected from those already known, for example, a method of continuously supplying the mixture to the decomposition process using a melt extruder.

[0166] <<Recycling>>

[0167] In the recycling process, the products of the chemicals obtained through thermal decomposition, namely liquid substances and gases, are recovered. There are no particular limitations on the recycling method; appropriate methods can be selected from known methods depending on the type of product obtained. For example, methods such as separating gaseous products by atmospheric or pressurized distillation and separating liquid hydrocarbons by atmospheric or vacuum distillation can be cited.

[0168] <<Separation>>

[0169] In the separation process, only the useful components are separated from the recovered liquid substances and gases, while the unwanted components are removed.

[0170] The substance produced by the method of manufacturing the chemicals disclosed herein may, in addition to at least one of the groups selected from alkenes and aromatic hydrocarbons having two to five carbon atoms, also be produced as a by-component alkanes having two to five carbon atoms.

[0171] In the separation process, there are no particular limitations on the method for separating the useful components and by-products, and a suitable method can be selected from known methods depending on the type of product or by-product obtained.

[0172] The above-described chemical manufacturing methods enable the high-yield and efficient production of at least one chemical selected from the group consisting of olefins and aromatic hydrocarbons having 2 to 5 carbon atoms. The manufactured chemical can be used as a base chemical suitable for chemical recycling.

[0173] (device)

[0174] The apparatus disclosed herein is an apparatus for manufacturing at least one chemical selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons, comprising: a storage section for a mixed plastic containing: a polyolefin, and at least one selected from the group consisting of aromatic plastics and chlorinated plastics; a fixed-bed reaction section having a packing layer filled with packing material; a mixed plastic supply section supplying the mixed plastic from the storage section to the fixed-bed reaction section; a gas supply section supplying an inert gas to the fixed-bed reaction section; and a heating section heating the temperature of the packing layer to below 820°C. The apparatus of this disclosure may also include other components as needed.

[0175] The apparatus disclosed herein is suitable for performing the method of manufacturing the chemicals disclosed herein.

[0176] (First Implementation)

[0177] Hereinafter, embodiments of the apparatus of this disclosure will be described with reference to the accompanying drawings. Figure 1This is a schematic cross-sectional view illustrating an example of the apparatus of this disclosure. The embodiments shown below illustrate an apparatus for implementing the technical concept of this disclosure, and are not intended to limit this disclosure to the following. Furthermore, the dimensions, materials, shapes, and relative arrangements of the constituent components described below, unless specifically stated otherwise, are not intended to limit the scope of this disclosure, but are intended as examples. Additionally, for clarity, the size and positional relationships of the components shown in the drawings are sometimes exaggerated. Furthermore, to avoid making the drawings overly complex, schematic diagrams with some elements omitted are used in the schematic cross-sectional views.

[0178] The apparatus 100 includes: a fixed-bed reaction section 1 with a packing layer 2, a mixed plastic supply section 3, a gas supply section 4, and a heating section 5.

[0179] Fixed-bed reaction section

[0180] The fixed-bed reaction section 1 is a component having a packing layer 2 filled with packing material 2a. Regarding the structure, shape, material, and size of the fixed-bed reaction section 1, there are no particular limitations as long as the packing layer 2 can be configured and a raw material M comprising at least one of the following: polyolefins and chlorinated plastics. The selection can be made appropriately according to the purpose; for example, a cylindrical tube can be used. To fix the packing material inside the tube, the tube can also be blocked with materials that allow organic compounds to flow, such as glass wool.

[0181] <Mixed Plastics Supply Department>

[0182] The mixed plastic supply unit 3 is a component that supplies raw material M containing mixed plastic to the fixed bed reactor 1. Examples of mixed plastic supply units 3 include: a raw material flow unit 3a for circulating the raw material M containing mixed plastic, and a raw material input unit 3b for feeding the raw material M containing mixed plastic into the fixed bed reactor 1. The mixed plastic supply unit 3 may also utilize a known pump or the like to supply the raw material M to the fixed bed reactor 1.

[0183] Alternatively, the mixed plastic supply unit 3 may also have a material supply stop unit, such as a stopper capable of stopping the supply of the raw material M containing the mixed plastic. With a material supply stop unit, the mixed plastic can be intermittently supplied to the fixed-bed reaction unit 1. The material supply stop unit may, for example, be located at the inlet of the material input unit 3b.

[0184] <Gas Supply Department>

[0185] The gas supply unit 4 is a component that supplies inactive gas G to the fixed bed reaction unit 1. Examples of gas supply units 4 include: a gas flow unit 4a through which inactive gas G flows, and a pump 4b through which inactive gas G flows in a certain amount for a certain period of time.

[0186] <Heating section>

[0187] The heating element 5 is a component that heats the filler layer 2 to below 820°C. There are no particular limitations on the heating element 5; it can be an external heating method that heats the filler layer by transferring heat from the outside, or an internal heating method that heats the filler layer itself. For example, a known electric furnace can be used as an external heating element. For example, a resistance heating method can be used as an internal heating element. This method involves using a conductive material such as silicon carbide as the filler, installing electrodes at both ends of the filler layer, and applying a voltage between the electrodes to generate heat.

[0188] The temperature of the packing layer 2 can be measured by inserting a thermocouple into the center of the packing layer 2.

[0189] <Other Components>

[0190] Other components are not particularly limited and can be appropriately selected according to the purpose. For example, storage unit 6, cooling unit 7, gas product recovery unit 8, and measuring unit for determining the yield of useful components can be mentioned.

[0191] Storage Department

[0192] Storage section 6 is a component for storing raw material M containing mixed plastic and other components as needed, wherein the mixed plastic contains: polyolefin, and at least one selected from the group consisting of aromatic plastic and chlorinated plastic.

[0193] The structure, shape, material, and size of the storage unit 6 are not particularly limited as long as it can store raw material M containing mixed plastics, and can be appropriately selected according to the purpose.

[0194] There is no particular limitation on the number of storage units 6; there may be one or more. When the device 100 has multiple storage units 6, for example, it can be used to store mixed plastics containing polyolefins and at least one of the following: aromatic plastics and chlorinated plastics, wherein the composition and content of each component are different.

[0195] Cooling Section

[0196] The cooling unit 7 is a component that cools the products obtained from the fixed-bed reaction unit 1. The cooling unit 7 is preferably disposed between the fixed-bed reaction unit 1 and the gas product recovery unit 8.

[0197] Examples of cooling units 7 include a collector 7a that cools the product and a cold-keeping unit 7b that cools the collector 7a. The structure, shape, material, and size of the collector 7a and the cold-keeping unit 7b are not particularly limited as long as they can cool the product, and can be appropriately selected according to the purpose.

[0198] The collector 7a can contain the organic solvent 7c of the dissolved product. Using the organic solvent 7c, the useful components in the product, especially the liquid useful components, can be condensed. A non-aqueous solvent is preferred as the organic solvent for the dissolved product. Examples of non-aqueous solvents include aromatic organic solvents such as monochlorobenzene, o-dichlorobenzene, and mesitylene.

[0199] Useful components dissolved in non-aqueous solvents can be appropriately separated by atmospheric distillation.

[0200] There are no particular limitations on the cold insulation section 7b as long as it can cool the collector 7a; for example, it can also contain refrigerant 7d. Refrigerant 7d can be, for example, ice water.

[0201] <<Gas Product Recovery Department>>

[0202] The gas product recovery unit 8 is a component that recovers gaseous products containing useful components produced by the apparatus 100. There may be only one gas product recovery unit 8, or there may be two or more.

[0203] There are no particular restrictions on the structure, shape, material, and size of the gas product recovery unit 8. It can be appropriately selected according to the purpose and the type of product. For example, well-known containers can be cited.

[0204] In addition, the gaseous product recovery unit 8 may also contain solvents capable of separating useful components. There are no particular restrictions on the solvent, and it can be appropriately selected according to the types of useful components that can be recovered. For example, solvents used to extract useful components from liquid products include ethanol, hexane, dimethylformamide, cyclopentane, and water.

[0205] The useful components in the gaseous products can be further separated appropriately by pressure distillation.

[0206] <<Measurement Department>>

[0207] The measuring unit is a component that measures the yield of useful components in a product containing useful components manufactured by apparatus 100.

[0208] The measuring unit can be located inside the device 100 or connected to the outside of the device 100.

[0209] There are no particular restrictions on the measurement unit as long as it can determine the yield of the useful components in the product, and known measuring devices can be used. Examples of known measuring devices include flame ionization detectors (FID) and thermal conductivity detectors (TCD).

[0210] There are no particular restrictions on the structure, shape, material, and size of the measuring unit; it can be appropriately selected according to the purpose and the type of product.

[0211] Apparatus 100 can, for example, perform the supply in the method for manufacturing the compound of the present disclosure by supplying raw material M containing mixed plastic stored in storage unit 6 to fixed-bed reaction unit 1 using mixed plastic supply unit 3, wherein the mixed plastic contains at least one selected from the group consisting of aromatic plastics and chlorinated plastics, and a polyolefin. Fixed-bed reaction unit 1 functions as a fixed-bed reactor in the method for manufacturing the compound of the present disclosure.

[0212] Then, while supplying inactive gas G from gas supply unit 4 to fixed bed reaction unit 1, the fixed bed reaction unit 1 is heated to below 820°C using heating unit 5, thereby enabling the heating process in the compound manufacturing method of this disclosure to be performed.

[0213] The product containing useful components obtained by heating can be recovered and separated in the method for manufacturing the compound disclosed herein in the cooling section 7 and the gas product recovery section 8.

[0214] The method for manufacturing the compound disclosed herein describes the chemical produced by the apparatus 100 of this disclosure.

[0215] (Second Implementation)

[0216] Figure 2 This is a schematic cross-sectional view showing another example of the device disclosed herein. The device of the second embodiment is the same as the device of the first embodiment, except that the configuration of the cooling unit 7 is different.

[0217] In the apparatus of the second embodiment, the product outlet of the tube connected to the fixed bed reaction section 1, which is located in the collector 7a of the cooling section 7, is placed in the organic solvent 9c, so that the gaseous product is bubbled in the organic solvent 9c.

[0218] [Example]

[0219] The present disclosure is illustrated by the following examples and comparative examples, but the present disclosure is not limited to these examples and comparative examples.

[0220] (Example 1)

[0221] <Preparation of Hybrid Plastics>

[0222] A mixed plastic was prepared by mixing polyethylene (HI-ZEX 1300J, manufactured by Prime Polymer Co., Ltd.), polypropylene (Prime Polypro J108M, manufactured by Prime Polymer Co., Ltd.), and polystyrene (PSJ-Polystyrene SGP10-K3900, manufactured by PS Japan Co., Ltd.) in a 1:1:1 (w / w ratio. The prepared mixed plastic is represented as "PE+PP+PS" in Tables 1 and 2.

[0223] <Preparation of the apparatus>

[0224] Silicon carbide (SiC) particles (trade name: Carborundum, 16 mesh (particle size: 1.119 mm), manufactured by Tokoyaku Co., Ltd.) were filled into a quartz tube with an inner diameter of 2.2 cm, with a filling length of 6 cm. 35 g of silicon carbide particles were used. The quartz tube was placed in a vertically oriented tubular furnace (trade name: ARF-30MC, manufactured by Asahi Rika Co., Ltd.). At the top of the tubular furnace, a manual powder feeding device (airless feed stopcock, manufactured by Asahi Seika Co., Ltd.) for introducing mixed plastics and a gas inlet were connected, and connected to the inlet side of the quartz tube. Additionally, at the bottom of the tubular furnace, one end of a gas extraction pipe was connected. The other end of the gas extraction pipe was connected to the inlet side of a cooling trap containing 15 mL of o-dichlorobenzene (premium grade reagent, manufactured by Kanto Chemical Co., Ltd.). It should be noted that the cooling trap was placed in an ice bath. Connect one end of another gas take-off pipe to the outlet side of the cooling trap, and connect the other end of the other gas take-off pipe to the gas bladder (10L volume). Insert a thermocouple into the center of the silicon carbide filled in the quartz tube. Blow nitrogen gas into the tubular furnace at a flow rate of 400 mL / min through the gas inlet, set the temperature of the tubular furnace to 700°C, and begin heating.

[0225] <Decomposition of Mixed Plastics>

[0226] After the furnace reaches the set temperature of 700°C and stabilizes, 0.33 g of mixed plastic is fed into the quartz tube from the manual powder feeding device over a period of 4 minutes under a nitrogen flow rate of 400 mL / min. This operation is repeated 6 times. Subsequent feedings of mixed plastic are performed after the furnace temperature has returned to a range between 680°C and 700°C. After a total of 1.98 g of mixed plastic has been fed, the generated gas is collected using an airbag. Furthermore, the airbag is separated from the device 5 minutes after the complete feeding of mixed plastic. Additionally, the cooling collector is separated from the device after returning to room temperature (25°C ± 5°C) for approximately 3 minutes.

[0227] (Example 2)

[0228] Except that the furnace temperature setting in Example 1 was changed from 700°C to 750°C, the mixed plastic was decomposed in the same manner as in Example 1.

[0229] (Example 3)

[0230] Except that the set temperature inside the furnace in Example 1 was changed from 700°C to 800°C, the mixed plastic was decomposed in the same manner as in Example 1.

[0231] (Example 4)

[0232] Except that the feeding time for each batch of mixed plastic in Example 1 was changed from 4 minutes to 3 minutes, the mixed plastic was decomposed in the same manner as in Example 1.

[0233] (Example 5)

[0234] Except that the nitrogen flow rate in Example 1 was changed from 400 mL / min to 200 mL / min, the decomposition of the mixed plastic was carried out in the same manner as in Example 1.

[0235] (Example 6)

[0236] Except that the nitrogen flow rate in Example 1 was changed from 400 mL / min to 500 mL / min, the decomposition of the mixed plastic was carried out in the same manner as in Example 1.

[0237] (Example 7)

[0238] Except that the 35g silicon carbide particles were replaced with 36g alumina particles (Al2O3) (trade name: Alumina Ball HD-3, diameter: 30mm, manufactured by Nikkato Co., Ltd.) in Example 1, the mixed plastic was decomposed using the same method as in Example 1.

[0239] (Example 8)

[0240] Except that the 35g silicon carbide particles were replaced with 55g of zirconia / silica mixture particles (trade name: Zirconia ball CZS 0160, diameter: 1.40mm~1.60mm, manufactured by AS ONE Co., Ltd., composition: ZrO2 / 55%~65%, SiO2 / 35%~45%) in Example 1, the mixed plastic was decomposed in the same way as in Example 1.

[0241] (Example 9)

[0242] Except that the type of filler in Example 1 was changed from silicon carbide particles to carbon-coated silicon carbide particles (sometimes referred to as "surface-treated SiC") manufactured by the following method, the mixed plastic was decomposed in the same manner as in Example 1.

[0243] <Preparation of carbon-coated silicon carbide particles>

[0244] In a 250 mL covered container, weigh 0.50 g of citric acid monohydrate (citric acid monohydrate, premium grade, manufactured by Fujifilm and Koichi Chemical Co., Ltd.) and 10 g of ethanol (premium grade, manufactured by Kanto Chemical Co., Ltd.), cover and stir until the citric acid is completely dissolved. Add 66 g of silicon carbide particles (trade name: DENSIC C, particle size (JIS R 6001-1-2017) F10, manufactured by Resonac Co., Ltd.) to the container and stir to coat the entire silicon carbide particle with the solution. Remove the container lid and place it in a vacuum desiccator, drying at room temperature under reduced pressure to less than 20 kPa. Note that the container should be removed from the vacuum desiccator and stirred every tens of minutes until completely dry. Transfer the completely dried mixture to an alumina boat and calcine at 800 °C for 1 hour in a nitrogen atmosphere to obtain carbon-coated silicon carbide particles.

[0245] (Example 10)

[0246] Except that the nitrogen flow rate in Example 9 was changed from 400 mL / min to 200 mL / min, the decomposition of the mixed plastic was carried out in the same manner as in Example 9.

[0247] (Comparative Example 1)

[0248] Except that the set temperature inside the furnace in Example 1 was changed from 700°C to 850°C, the mixed plastic was decomposed in the same manner as in Example 1.

[0249] <<Analysis of the contents of the airbag>>

[0250] In Examples 1-10 and Comparative Example 1, the yields of useful components and byproducts in the thermally decomposed gas recovered into the airbag were determined using the following method based on the carbon molar number (Cmol%).

[0251] Add 40 μL of cyclopentane (>98.0%, manufactured by Tokyo Chemical Industry Co., Ltd.) to the gasbag. Heat the gasbag to approximately 40°C to completely vaporize the contents, then gently knead the gasbag to mix the contents. Use the resulting contents as the analytical sample and analyze them using gas chromatography (GC) under the GC analytical conditions described below. Calculate the proportion (Cmol%) of each component in the thermal decomposition gas within the gasbag based on the ratio of the peak area of ​​each component to the peak area of ​​cyclopentane. The results are shown in Tables 1 and 2.

[0252] [GC Analysis Conditions]

[0253] • Device: Nexis GC-2030 (manufactured by Shimadzu Corporation)

[0254] • Column: Rt-Alumina BOND (diameter: 0.32mm, length: 30m, manufactured by Restek)

[0255] • Types of carrier gas: Ar

[0256] • Carrier gas flow rate: 360 mL / min

[0257] • Injection temperature: 200℃

[0258] • Injection volume: 1 mL

[0259] • Flow split ratio: 1 / 200

[0260] • Column temperature: After holding at 120°C for 9 minutes, increase the temperature to 200°C at a rate of 10°C / minute, and hold at 200°C for 30 minutes.

[0261] • Detector: Flame Ionization Detector (FID)

[0262] • Detector temperature: 200℃

[0263] <<Analysis of the contents of the cooling trap>>

[0264] In Examples 1-10 and Comparative Example 1, the yields of useful components and byproducts recovered from the thermal decomposition components in the cooling trap were determined using the following method based on the carbon molar number (Cmol%).

[0265] Transfer the contents to a sample vial. Add 2 mL of o-dichlorobenzene (premium grade, manufactured by Kanto Chemical Co., Ltd.) to the nearly empty cooling trap to dissolve the contents, then transfer the solution back to the sample vial. Repeat this process three times to clean the cooling trap. Add cyclopentane (>98.0%, manufactured by Tokyo Chemical Industry Co., Ltd.) as an internal standard to the sample vial as the analytical sample, and analyze using gas chromatography (GC) under the GC analytical conditions described below. Calculate the proportion (Cmol%) of each component in the thermally decomposed components in the cooling trap based on the ratio of the peak area of ​​each component to the peak area of ​​cyclopentane. The results are shown in Tables 1 and 2.

[0266] [GC Analysis Conditions]

[0267] • Device: Nexis GC-2030 (manufactured by Shimadzu Corporation)

[0268] • Column: DB-1 (Diameter: 0.25mm, Length: 30m, manufactured by Agilent Technologies)

[0269] • Carrier gas type: He

[0270] • Carrier gas flow rate: 97 mL / min

[0271] • Injection temperature: 350℃

[0272] • Injection volume: 1 μL

[0273] • Flow split ratio: 1 / 50

[0274] • Column temperature: Set the temperature program in the following order: 35℃ (10 minutes) → temperature increase (5℃ / minute) → 350℃ (10 minutes).

[0275] • Detector: Flame Ionization Detector (FID)

[0276] • Detector temperature: 350℃

[0277] <<Calculation of Sintering Loss Rate>>

[0278] In Examples 1-10 and Comparative Example 1, after the decomposition of the mixed plastic was completed, o-dichlorobenzene (premium grade reagent, manufactured by Kanto Chemical Co., Ltd.) and acetone (premium grade reagent, manufactured by Kanto Chemical Co., Ltd.) were introduced through a manual powder feeding device to clean the packing layer. Then, the mixture was allowed to stand for 10 minutes under a nitrogen atmosphere at a flow rate of 1,600 NmL / min to remove o-dichlorobenzene and acetone from the packing layer. Next, the quartz tube with the packing layer was sintered at 200°C for 30 minutes under a nitrogen atmosphere at a flow rate of 1,600 NmL / min. The mass X after sintering under a nitrogen atmosphere was measured. Then, the quartz tube with the packing layer was sintered at 600°C for 30 minutes under an air atmosphere at a flow rate of 500 NmL / min. The mass Y after air sintering was measured. Based on the measured value, the sintering loss rate was calculated using the following formula. This value corresponds to the amount of coking. The sintering loss rate in Examples 1-10 and Comparative Example 1 was 0 by mass.

[0279] Sintering loss rate (mass%) = (mass X - mass Y) / mass of raw material M input × 100

[0280] In Tables 1 and 2, “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 recorded in Tables 1 and 2 to the number of moles of carbon atoms (Cmol) contained in the mixed plastic.

[0281] In Tables 1 and 2, “Total Yield of Useful Components” refers to the ratio of the total number of moles of carbon atoms in the 2- to 5-carbon olefins and useful aromatic hydrocarbons in the product to the total number of moles of carbon atoms in the mixed plastic. “Useful Components” represent ethylene, propylene, 4-carbon olefins (trans-2-butene, 1-butene, 2-methylpropene, cis-2-butene, 1,3-butadiene, and isobutene), 5-carbon olefins (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, the three positional isomers of xylene (p-xylene, m-xylene, and o-xylene), and styrene).

[0282] In addition, in Tables 1 and 2, the "O / P ratio for carbon numbers 2 to 5" is calculated according to the following formula 3.

[0283] [Formula 3]

[0284] The O / P ratio for carbon 2 to carbon 5 hydrocarbons = [total percentage of alkenes (Cmol%)] / [total percentage of alkanes (Cmol%)]

[0285] Since the sintering loss rate of Examples 1-10 and Comparative Example 1 was 0% by mass, the "Yield of Useful Components" and "Yield of By-products" in Tables 1 and 2 are the same values ​​as the ratio of the total number of moles of carbon atoms in each product of Examples 1-10 and Comparative Example 1 to the number of moles of carbon atoms (Cmol) contained in the total mass of the product. Similarly, the "Total Yield of Useful Components" in Tables 1 and 2 are the same values ​​as the ratio of the total number of moles of carbon atoms in the olefins with 2 to 5 carbon atoms and useful aromatic hydrocarbons in the products of Examples 1-10 and Comparative Example 1 to the number of moles of carbon atoms (Cmol) contained in the total mass of the product.

[0286] [Table 1]

[0287]

[0288] [Table 2]

[0289]

[0290] As described above, this disclosure has been illustrated with specific implementation methods and embodiments. However, these implementation methods and embodiments are merely presented as examples, and this disclosure is not limited to the above implementation methods and embodiments. The above implementation methods can be implemented in various other ways, and various combinations, omissions, substitutions, additions, modifications, etc., can be made without departing from the spirit of the invention. These implementation methods and their variations are included in the scope and spirit of the invention, and are included in the same scope as the invention described in the claims.

[0291] This international application claims priority to Japanese Patent Application No. 2024-028236, filed on February 28, 2024, and incorporates the entire contents of Japanese Patent Application No. 2024-028236.

[0292] Explanation of reference numerals in the attached figures

[0293] 100: Device

[0294] 1: Fixed-bed reaction section

[0295] 2: Filler layer

[0296] 2a: Packing material

[0297] 3: Mixed Plastics Supply Department

[0298] 3a: Raw Material Distribution Department

[0299] 3b: Raw Material Input Department

[0300] 4: Gas Supply Department

[0301] 4a: Gas Circulation Department

[0302] 4b: Pump

[0303] 5: Heating section

[0304] 6: Storage Department

[0305] 7: Cooling section

[0306] 7a: Trapper

[0307] 7b: Cold preservation department

[0308] 7c: Organic solvent

[0309] 7d: Refrigerant

[0310] 8: Gas Product Recovery Department

[0311] M: Raw materials

[0312] G: Inactive gas

Claims

1. A method for manufacturing a chemical substance, characterized in that, It is a method for manufacturing at least one chemical selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons. The manufacturing method includes: A mixed plastic is fed into a fixed-bed reaction section having a filler-filled layer, wherein the mixed plastic comprises: at least one selected from the group consisting of aromatic plastics and chlorinated plastics, and a polyolefin; and The temperature of the filler layer is set below 820°C, and the mixed plastic is thermally decomposed in the presence of an inactive gas.

2. The method for manufacturing the chemical according to claim 1, wherein, In the thermal decomposition, the volume of the filler layer is set as V (cm). 3 The volume of the filler in the filler layer is set as Vs (cm). 3 When the flow rate of the inactive gas is set to v (mL / min), the residence time of the inactive gas in the fixed bed reaction section, calculated by the ratio [(V-Vs) / v], is less than 2 seconds.

3. The method for manufacturing the chemical according to claim 1 or claim 2, wherein, In the thermal decomposition, the temperature of the filler layer is set to below 770°C.

4. A method for manufacturing the chemical according to any one of claims 1 to 3, wherein, In the thermal decomposition, the porosity of the filler layer is above 20% and below 80%.

5. A method for manufacturing the chemical 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. A method for manufacturing the chemical according to any one of claims 1 to 5, wherein, The aromatic plastic contains polystyrene.

7. A method for manufacturing the chemical according to any one of claims 1 to 6, wherein, The chlorinated plastic contains at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride, and chlorinated polyethylene.

8. A method for manufacturing the chemical according to any one of claims 1 to 7, wherein, In the thermal decomposition, the volume of the filler layer is set as V (cm). 3 The volume of the filler in the filler layer is set as Vs (cm). 3 When the flow rate of the inactive gas is set to v (mL / min), the residence time of the inactive gas in the fixed bed reaction section, calculated by the ratio [(V-Vs) / v], is 0.1 seconds or more.

9. A method for manufacturing the chemical according to any one of claims 1 to 8, wherein, In the thermal decomposition, the temperature of the filler layer is set to above 500°C.

10. A method for manufacturing the chemical according to any one of claims 1 to 9, wherein, The aromatic hydrocarbon is selected from at least one of the following groups: benzene, toluene, xylene, ethylbenzene, and styrene.

11. An apparatus, characterized in that, It is an apparatus for the manufacture of at least one chemical selected from the group consisting of olefins having 2 to 5 carbon atoms and aromatic hydrocarbons. The device has: A fixed-bed reaction section having a packing layer filled with packing material; A mixed plastic supply unit supplies mixed plastic to the fixed-bed reaction unit, wherein the mixed plastic contains: polyolefin, and at least one selected from the group consisting of aromatic plastics and chlorinated plastics; A gas supply unit that supplies inactive gas to the fixed-bed reaction unit; and The heating section heats the temperature of the filler layer to below 820°C.

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