Olefin production method

Abstract

An olefin production method is provided involves a step of catalytically cracking a raw material containing at least a polyolefin and an organochlorine compound in the presence of a zeolite catalyst having a sodium atom content of less than 0.1% by mass. This method improves olefin yield.

Description

Olefin production process

[0001] The present invention relates to a process for producing an olefin and a method for regenerating a catalyst used in the process.

[0002] The main raw materials in the petrochemical industry are lower olefins such as ethylene and propylene, obtained by cracking and reforming naphtha, and aromatic hydrocarbons such as benzene, toluene, and xylene. A wide variety of chemical products are synthesized using these as starting materials. Among these, plastics are the most widely produced and are widely used in a range of industrial and everyday products due to their excellent properties as materials, such as light weight, corrosion resistance, and ease of molding. As a result, the amount of waste plastic being discharged is also enormous.

[0003] Non-Patent Document 1 describes a chemical recycling technology for efficiently decomposing polyethylene into petrochemical raw materials. Specifically, the document describes a method for catalytically decomposing polyethylene using sodium atom-containing MFI zeolite to obtain olefins having 2 to 5 carbon atoms.

[0004] Monthly Fine Chemical (December 2017 issue, Vol. 46, No. 12)

[0005] However, the yield of olefins having 2 to 3 carbon atoms obtained by the method described in Non-Patent Document 1 is not necessarily sufficient. Therefore, the present invention provides a method for producing olefins that provides an excellent yield of olefins having 2 to 3 carbon atoms.

[0006] The present invention provides the following items [1] to

[14] . [1] A method for producing an olefin, comprising a step of catalytically cracking a raw material containing at least a polyolefin and an organic chlorine compound in the presence of a zeolite catalyst having a sodium content of less than 0.1% by mass. [2] The method for producing an olefin according to [1], wherein the zeolite catalyst is an MFI-type zeolite catalyst. [3] The method for producing an olefin according to [1] or [2], wherein the Si / Al ratio of the zeolite catalyst is 100 or more. [4] The method for producing an olefin according to [1] or [2], wherein the Si / Al ratio of the zeolite catalyst is 300 or more. [5] The method for producing an olefin according to [1], wherein the olefin is an olefin having 2 to 3 carbon atoms. [6] The method for producing an olefin according to any one of [1] to [5], wherein the sodium content of the zeolite catalyst is less than 0.05% by mass. [7] The method for producing an olefin according to any one of [1] to [6], wherein the organic chlorine compound comprises at least one of polyvinyl chloride and polyvinylidene chloride. [8] The method for producing an olefin according to [7], wherein the content of chlorine atoms in the raw material is 10% by mass or less. [9] The method for producing an olefin according to any one of [1] to [8], further comprising a step of thermally cracking the raw material before the catalytic cracking step.

[10] The method for producing an olefin according to any one of [1] to [9], further comprising a step of vaporizing the raw material before the catalytic cracking step, wherein the catalytic cracking step is a step of catalytically cracking the gaseous raw material.

[11] The method for producing an olefin according to any one of [1] to

[10] , wherein the catalytic cracking step is carried out at 450°C or higher and 600°C or lower.

[12] The method for producing an olefin according to any one of [1] to

[11] , wherein the zeolite catalyst is a regenerated catalyst.

[13] A method for regenerating a catalyst, comprising a step of calcining a used zeolite catalyst used in the method for producing an olefin according to any one of [1] to

[11] , in an atmosphere containing 1% by volume to 50% by volume of oxygen, to obtain a regenerated catalyst.

[14] A method for producing an olefin, comprising a step of catalytically cracking a raw material containing a polyolefin in the presence of a regenerated catalyst regenerated by the regeneration method according to

[13] .

[0007] The present invention can provide a production method that provides an excellent yield of olefins having 2 to 3 carbon atoms. The present invention also provides a catalyst regeneration method that can simply regenerate a regenerated catalyst that has high catalytic performance after regeneration from a spent zeolite catalyst used in the production method.

[0008] 1. Olefin Production Method The olefin production method according to the present invention comprises a step of catalytically cracking a raw material containing at least a polyolefin and an organic chlorine compound in the presence of a zeolite catalyst having a sodium content of less than 0.1 mass %. The olefin production method according to this embodiment will be specifically described below.

[0009] <Catalytic Cracking Step (Catalytic Cracking Step)> Raw Material Raw materials that can be applied to the olefin production method of this embodiment include at least a polyolefin and an organic chlorine compound.

[0010] Specific examples of polyolefins contained as raw materials include polyolefin-based plastics such as polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, and ethylene-α-olefin copolymer, as well as mixtures of two or more of these. Among these, polyethylene, polypropylene, and ethylene-propylene copolymer are preferred.

[0011] In addition to the polyolefin-based plastics, the raw materials may include other components such as polystyrene, polyamide, polycarbonate, polyurethane, polyester, polymethyl methacrylate, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, natural rubber, and synthetic rubber.

[0012] Specific examples of organic chlorine compounds contained as raw materials include polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC). The organic chlorine compound preferably contains at least one of polyvinyl chloride and polyvinylidene chloride.

[0013] In the olefin production method of the present embodiment, the upper limit of the content of chlorine atoms that may be contained in the raw material is about 30 mass %, and from the viewpoint of the yield of the target olefin, the content of chlorine atoms in the raw material is preferably 10 mass % or less.

[0014] The raw materials may include, for example, industrial products such as molded articles produced using the above-mentioned polyolefins, organic chlorine compounds, and other components. Specific examples of industrial products include plastic containers and packaging collected under the Container and Packaging Recycling Law.

[0015] The raw material may be in a solid state like the above-mentioned molded body, or may be a solid industrial product converted into a liquid and / or gaseous state, such as a liquid and / or gaseous mixture of the above-mentioned polyolefin, organic chlorine compound, and other components.

[0016] Zeolite Catalyst Examples of the zeolite catalyst used in this embodiment include beta zeolite, faujasite zeolite, L zeolite, ferrierite zeolite, mordenite zeolite, and MFI zeolite, and a zeolite catalyst made of MFI zeolite is preferred. The zeolite catalyst of this embodiment has a sodium content of less than 0.1% by mass. From the viewpoint of the yield of the target olefin, the sodium content of the zeolite catalyst of this embodiment is more preferably less than 0.05% by mass.

[0017] The zeolite catalyst used in this embodiment may typically contain silicon atoms, aluminum atoms, oxygen atoms, and hydrogen atoms as atoms other than sodium atoms. The zeolite catalyst may also contain atoms such as titanium atoms, chromium atoms, manganese atoms, iron atoms, cobalt atoms, nickel atoms, copper atoms, ruthenium atoms, rhodium atoms, palladium atoms, silver atoms, iridium atoms, platinum atoms, boron atoms, nitrogen atoms, magnesium atoms, phosphorus atoms, zinc atoms, and gallium atoms.

[0018] Here, the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms in the zeolite catalyst (Si / Al ratio) is preferably 100 or more, and more preferably 300 or more, from the viewpoint of improving the yield of the target olefin.

[0019] The sodium content and Si / Al ratio of the zeolite catalyst can be calculated by analyzing the zeolite catalyst according to a conventionally known ICP emission spectrometry method.

[0020] Here, MFI zeolite means a crystalline aluminosilicate having an MFI structure according to the structure code of the International Zeolite Association (IZA). Specific examples of MFI zeolite include H ＋ -ZSM-5, NH ４ ＋ -ZSM-5, Na ＋ -ZSM-5, Ca ２＋ MFI zeolite can be prepared by any suitable method known in the art, and commercially available H ＋ ZSM-5 may also be used. Identification of the MFI zeolite can be carried out by analysis using X-ray diffraction analysis.

[0021] A method for producing the zeolite catalyst used in this embodiment will be described below. The zeolite catalyst used in this embodiment can be produced by a production method including the steps of preparing a mixture containing a silicon source, an aluminum source, a template, and an alkali metal source, and crystallizing the mixture to obtain a zeolite. Here, the "template" refers to a substance that imparts a pore structure to the zeolite.

[0022] The silicon source may be any known silicon source used in the production of various zeolites, including tetraethyl orthosilicate, colloidal silica, silica gel dry powder, silica hydrogel, and sodium silicate.

[0023] As the aluminum source, a conventionally known aluminum source used in the production of various zeolites can be used. Specific examples of the aluminum source include aluminum nitrate, aluminum chloride, sodium aluminate, aluminum hydroxide, and aluminum alkoxide. Among these aluminum sources, aluminum nitrate or sodium aluminate is preferred.

[0024] The type of template that can be used in this embodiment is not particularly limited. As the template, conventionally known templates such as organic ammonium salts and amines that are generally used in the synthesis of zeolites can be used.

[0025] Specific examples of the template include tetrapropylammonium salt, tetraethylammonium salt, tetramethylammonium salt, benzyltrimethylammonium salt, tetrabutylammonium salt, propanolamine, ethanolamine, n-propylamine, morpholine, 1,5-diaminopentane, 1,6-diaminohexane, dipropylenetetramine, and triethylenetetramine. Among these templates, tetrapropylammonium salt (tetrapropylammonium hydroxide) is preferred.

[0026] Examples of alkali metal sources include alkali metal hydroxides, alkali metal chlorides, alkali metal bromides, and alkali metal sulfides. Specific examples of alkali metals include sodium and potassium.

[0027] When the alkali metal is sodium, specific examples of the sodium source include sodium hydroxide, sodium nitrate, sodium chloride, sodium bromide, sodium sulfate, sodium silicate, sodium aluminate, and compounds containing sodium as a counter cation.

[0028] When the alkali metal is potassium, specific examples of the potassium source include potassium hydroxide, potassium nitrate, potassium chloride, potassium bromide, potassium sulfate, potassium silicate, potassium aluminate, and compounds containing potassium as a counter cation.

[0029] In the mixture, the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms (Si / Al ratio) is preferably 100 or more, more preferably 300 or more. The ratio may be 10,000 or less, preferably 2,500 or less.

[0030] The ratio of the number of moles of each component in the mixture to the number of moles of silicon atoms preferably satisfies the following requirements: Template: 0.02 or more and 5.0 or less Alkali metal source: 0.01 or more and 0.2 or less Water: 2 or more and 100 or less

[0031] Furthermore, it is more preferable that the ratio of the number of moles of each component in the mixture to the number of moles of silicon atoms satisfies the following requirements: template: 0.05 or more and 2.0 or less alkali metal source: 0.04 or more and 0.3 or less water: 5 or more and 50 or less

[0032] The specific steps are described below: First, the above components (mixture) are stirred at room temperature for 1 hour to 48 hours (for example, 18 hours), and the resulting mixture is placed in a sealed pressure vessel (autoclave), where the mixture is treated at a temperature of 100°C to 200°C for 1 hour to 120 hours, thereby preparing a zeolite precursor.

[0033] After the crystallization is completed, the mixture (suspension) containing the prepared zeolite precursor is sufficiently cooled with ice water or the like, and after the cooling is completed, the mixture is subjected to solid-liquid separation (for example, centrifugation) to remove the supernatant, and the mixture is further washed with a sufficient amount of pure water to perform solid-liquid separation. This process is repeated until the pH of the removed supernatant becomes 8 or less.

[0034] Next, the mixture is dried at a temperature of 100°C to 150°C (e.g., 120°C) for 1 hour to 48 hours (e.g., 8 hours). Thereafter, the mixture may be calcined at a temperature of about 400°C to 700°C (e.g., 550°C) for 1 hour to 48 hours (e.g., 7 hours). Through the above steps, a zeolite (e.g., MFI zeolite) can be obtained.

[0035] The zeolite prepared as described above contains a relatively large amount of sodium or potassium contained in the alkali metal source, and therefore, in order to obtain the zeolite catalyst used in this embodiment, it is usually necessary to remove the alkali metal from the zeolite.

[0036] As a method for removing alkali metals from zeolite, a method of bringing zeolite into contact with an aqueous solution of an ammonium salt can be mentioned.

[0037] Examples of ammonium salts include ammonium salts of inorganic acids such as ammonium sulfate, ammonium hydrogen sulfate, ammonium carbonate, ammonium hydrogen carbonate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate, ammonium hydrogen pyrophosphate, ammonium pyrophosphate, ammonium chloride, and ammonium nitrate, and ammonium salts of organic acids such as ammonium acetate, etc. Among these, it is preferable to use ammonium sulfate, ammonium chloride, and ammonium nitrate.

[0038] Specifically, this step involves mixing an aqueous solution of an ammonium salt with zeolite and contacting them at a temperature of 50°C to 200°C for 1 to 48 hours, and repeating this step one or more times as necessary, thereby adjusting (reducing) the alkali metal content (e.g., the sodium atom content) to a desired content.

[0039] Next, the solid is allowed to cool sufficiently to separate the solid from the liquid, washed with a sufficient amount of pure water, and dried at a desired temperature between 60°C and 150°C.

[0040] Thereafter, it is preferable to perform firing at a temperature of about 400° C. to 700° C. (for example, 550° C.) for 1 hour to 48 hours (for example, 5 hours).

[0041] By preparing the catalyst as described above, the amount of sodium atoms, which is an alkali metal, can be reduced to obtain the zeolite catalyst of the present embodiment having a sodium content of less than 0.1 mass %.

[0042] The temperature in the catalytic cracking process (contact temperature T ２) is usually 400°C to 700°C, preferably 450°C to 600°C (450°C or higher and 600°C or lower).

[0043] The pressure in the catalytic cracking process (contact pressure P ２ ) is usually 0 MPaG to 5 MPaG, preferably 0 MPaG to 0.5 MPaG.

[0044] In the catalytic cracking process, steam or nitrogen gas, CO ２ An inert gas such as a gas may also be present.

[0045] The catalytic cracking step can be carried out using any suitable conventionally known reactor, for example, made of quartz glass, carbon steel, stainless steel, Inconel alloy, Hastelloy alloy, Incoloy alloy, or Monel alloy.

[0046] The olefins obtained in the catalytic cracking step are usually olefins having 2 to 5 carbon atoms, such as ethylene, propylene, and butene, and preferably olefins having 2 to 3 carbon atoms.

[0047] The zeolite catalyst used in the catalytic cracking step may be a regenerated catalyst (details will be described later). That is, the olefin production method of this embodiment may include a step of catalytically cracking a raw material containing a polyolefin in the presence of a regenerated catalyst.

[0048] <Thermal cracking step (thermal cracking step)> In the olefin production method of this embodiment, from the viewpoint of further improving the olefin yield, it is preferable that a step of thermally cracking the feedstock is further included before the catalytic cracking step already described, and that the catalytic cracking step is a step of catalytically cracking the feedstock in a gaseous state, a liquid state, or a mixture thereof.

[0049] The thermal cracking step in the olefin production method of this embodiment can be carried out using any suitable conventionally known apparatus, adopting conditions appropriate for the selected raw material and the components contained in the raw material.

[0050] The thermal cracking step of this embodiment can be carried out using a vessel separate from the vessel in which the catalytic cracking step described above is carried out. Alternatively, the thermal cracking step and the catalytic cracking step of this embodiment may be carried out continuously using the same reaction vessel.

[0051] The thermal decomposition temperature T １ and the contact temperature T in the catalytic cracking step. ２ It is preferable that the condition represented by the following formula is satisfied: 0°C≦T ２ -T １ ≦200°C

[0052] Pyrolysis temperature T in the pyrolysis process １ is usually 350 to 550°C, preferably 400 to 500°C.

[0053] Pyrolysis pressure P in the pyrolysis process １ is usually 0 MPaG to 5 MPaG, preferably 0 MPaG to 0.5 MPaG. １ and contact pressure P ２ The relationship between １ ≧P ２ It is preferable that:

[0054] In the thermal decomposition process, water vapor or nitrogen gas, CO ２ An inert gas such as a gas may also be present.

[0055] The pyrolysis step can be carried out using any suitable conventionally known reaction vessel, for example, quartz glass, carbon steel, stainless steel, Inconel alloy, Hastelloy alloy, Incoloy alloy, or Monel alloy.

[0056] The pyrolysis product of the raw material obtained by the pyrolysis step usually contains hydrocarbons having about 1 to 50 carbon atoms, hydrogen, etc., in a liquid, gaseous or mixed state.

[0057] <Step of Vaporizing Feedstock (Vaporization Step)> In the olefin production method of this embodiment, it is preferable to further include a vaporization step before the catalytic cracking step, and to make the catalytic cracking step a step of catalytically cracking a gaseous feedstock.

[0058] The vaporization step in the olefin production method of this embodiment can be carried out using any suitable conventionally known apparatus, adopting conditions appropriate for the selected raw material and the components contained in the raw material.

[0059] The vaporization step of this embodiment can be carried out using the vessel in which the catalytic cracking step described above is carried out. Furthermore, the vaporization step and the catalytic cracking step of this embodiment may be carried out continuously using the same reaction vessel.

[0060] Temperature T in the vaporization process ３ is usually 350 to 550°C, preferably 400 to 500°C.

[0061] Pressure P in the vaporization process ３ is usually 0 MPaG to 5 MPaG, and preferably 0 MPaG to 0.5 MPaG. By setting the pressure in this range, the raw material can be efficiently converted into a gaseous state.

[0062] In the vaporization process, water vapor or nitrogen gas, CO ２ An inert gas such as a gas may also be present.

[0063] The vaporization step can be carried out using any suitable conventionally known reaction vessel, for example, quartz glass, carbon steel, stainless steel, Inconel alloy, Hastelloy alloy, Incoloy alloy, or Monel alloy.

[0064] The decomposition products of the raw material obtained by the vaporization step contain gaseous hydrocarbons having about 1 to 50 carbon atoms, hydrogen, etc.

[0065] In the olefin production method of this embodiment, the thermal cracking step, vaporization step, and catalytic cracking step already described may be carried out integrally and continuously in this order.

[0066] According to the olefin production method of this embodiment, even when using raw materials containing organic chlorine compounds, which are inevitably contained in raw materials containing polyolefins, such as food packaging containers, and which have conventionally been required to be removed in advance because they can act as catalyst poisons, olefins can be efficiently produced without removing the organic chlorine compounds in advance. Note that, when carrying out the olefin production method of this embodiment, the organic chlorine compounds may be removed in advance from the raw materials.

[0067] 2. Catalyst Regeneration Method The zeolite catalyst used in the catalytic cracking step of this embodiment may be a regenerated catalyst. That is, the olefin production method of this embodiment can be carried out by applying a polyolefin-containing raw material (which may further contain an organic chlorine compound) to the catalytic cracking step in the presence of a regenerated catalyst obtained by regenerating a used zeolite catalyst used in the olefin production method already described.

[0068] The catalyst regeneration method of this embodiment will be specifically described below. The catalyst regeneration method of this embodiment includes a step of calcining the catalyst in an atmosphere containing 1% by volume to 50% by volume of oxygen to obtain a regenerated catalyst.

[0069] The step of obtaining the regenerated catalyst is preferably carried out in an atmosphere containing oxygen in the range of 1% by volume to 50% by volume, more preferably in an atmosphere containing oxygen in the range of 5% by volume to 30% by volume.

[0070] The step of obtaining the regenerated catalyst can be carried out, for example, in an air atmosphere, a nitrogen gas atmosphere, an argon gas atmosphere, a carbon dioxide gas atmosphere, or a mixed gas atmosphere thereof, while adjusting the oxygen concentration in the atmosphere by any suitable method known in the art.

[0071] The temperature in the step of obtaining the regenerated catalyst is preferably in the range of 400°C to 700°C (for example, 550°C), and more preferably in the range of 450°C to 600°C.

[0072] The treatment time in the step of obtaining the regenerated catalyst is preferably 30 minutes to 48 hours (for example, 5 hours), and more preferably 1 hour to 24 hours.

[0073] The regenerated catalyst obtained by the above-described catalyst regeneration method can be used in the olefin production process of this embodiment in the same manner as an unused "zeolite catalyst" for the catalytic cracking reaction of polyolefins, without any particular adjustment of conditions such as temperature, treatment time, and atmosphere.

[0074] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0075] Reference Example 1 Preparation of Zeolite Catalyst A Aluminum nitrate nonahydrate (0.29 g), 20.3 mass% tetrapropylammonium hydroxide aqueous solution (76.8 g), sodium hydroxide (0.77 g), and tetraethyl orthosilicate (64.0 g) were added to a 400 mL PTFE vessel equipped with a stirrer, and the mixture was stirred at room temperature for 18 hours to obtain a mixture. After that, ion-exchanged water (56.6 g) was added to this mixture, and the entire amount was transferred to a stainless steel (SUS) autoclave equipped with a 200 mL PTFE cylindrical vessel.

[0076] In the mixture, the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms was 400, the ratio of the number of moles of tetrapropylammonium hydroxide to the number of moles of silicon atoms was 0.56, the ratio of the number of moles of sodium atoms to the number of moles of silicon atoms was 0.06, and the ratio of the number of moles of water to the number of moles of silicon atoms was 13.

[0077] The mixture was heated in an autoclave at 170°C for 24 hours and then cooled with ice water. After cooling, the mixture (suspension) in the cylindrical container was centrifuged and the supernatant was removed to obtain a zeolite precursor.

[0078] Water was added to the obtained zeolite precursor to form a suspension again, and the suspension was centrifuged and the supernatant was removed. This procedure was repeated until the pH of the supernatant became 8 or less, thereby forming a solid again.

[0079] The obtained solid was dried at 120° C. for 8 hours, pulverized in a mortar, and then calcined in a muffle furnace at 550° C. for 7 hours to obtain Zeolite 1 (14.1 g).

[0080] Zeolite 1 (6.6 g) and 0.5 M aqueous ammonium nitrate solution (300 mL) were added to a 500 mL resin container and allowed to stand for 6 hours at 60° C. The resulting mixture was then subjected to suction filtration using a Buchner funnel to recover the solid.

[0081] The recovered solid and 0.5 M aqueous ammonium nitrate solution (330 mL) were added to a flask, and the mixture was allowed to stand for 12 hours at a temperature of 60° C. Thereafter, the resulting mixture was subjected to suction filtration using a Buchner funnel to recover the solid.

[0082] Next, the recovered solid and 0.5 M ammonium nitrate aqueous solution (330 mL) were added to a flask and allowed to stand at 60° C. for 6 hours. The resulting mixture was then suction filtered using a Buchner funnel to recover the solid. The recovered solid was washed with water (500 mL) and dried at 90° C. for 6 hours to obtain a solid.

[0083] The resulting solid was calcined in an air atmosphere at 550° C. for 5 hours using a muffle furnace to obtain a powdery zeolite catalyst A (5.1 g).

[0084] Zeolite catalyst A was analyzed by ICP atomic emission spectrometry, and the content of sodium atoms was found to be less than 0.01 mass%, which is the lower detection limit, and the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms (Si / Al ratio) was 349. Furthermore, zeolite catalyst A was analyzed by X-ray diffraction analysis, and it was confirmed that it had an MFI structure.

[0085] Example 1 Production of Olefins The upstream reaction tube of two glass reaction tubes connected in series was packed with a raw material (weight ratio of LDPE:PVC=95:5) which was a mixture of polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.425 g) and organochlorine compound polyvinyl chloride (PVC) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Shin-Etsu PVC Straight Polymer TK-1000) (0.075 g), and the downstream reaction tube was packed with zeolite catalyst A (0.3 g).

[0086] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0087] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the zeolite catalyst A, and then the temperature of the downstream reaction tube was lowered to 525°C.

[0088] The step of pyrolyzing the raw material was carried out by passing nitrogen gas through at a flow rate of 10 NmL / min and setting the temperature of the electric furnace in the upstream reaction tube at 455°C, to obtain a pyrolyzed mixture of raw material.

[0089] Next, the pyrolyzed raw material was subjected to catalytic cracking. Specifically, in this process, the pyrolyzed raw material obtained as described above was heated to a temperature T ２ into the downstream reaction tube heated to 525° C., and the raw material was brought into contact with the catalyst. The entire amount of the liquid catalytic cracking product obtained 2 hours after the start of heating the raw material was recovered in a cooling trap cooled with ice water, and further, the entire amount of the gaseous catalytic cracking product was recovered in a gas bag.

[0090] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0091] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 37.1% based on the mass of the charged polyethylene.

[0092] Furthermore, the analytical value of the gaseous catalytic cracker was corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 34.4% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0093] Finally, the spent zeolite catalyst (spent zeolite catalyst B) was recovered from the reaction system.

[0094] Example 2 Regeneration of Spent Zeolite Catalyst B (Preparation of Regenerated Catalyst C) The spent zeolite catalyst B recovered in Example 1 was calcined in a muffle furnace in an air atmosphere (oxygen concentration 21% by volume) at a temperature of 550°C for 5 hours to obtain a regenerated zeolite catalyst as regenerated catalyst C.

[0095] Example 3 Production of Olefins Using Regenerated Catalyst C Two glass reaction tubes were connected in series. The upstream reaction tube was filled with polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.0 g) as a raw material, and the downstream reaction tube was filled with regenerated catalyst C (0.2 g).

[0096] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0097] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the regenerated catalyst C, and then the temperature of the downstream reaction tube was lowered to 525°C.

[0098] The step of pyrolyzing the raw material was carried out by passing nitrogen gas at a flow rate of 10 NmL / min and setting the temperature of the electric furnace in the upstream reaction tube at 455°C, to obtain a pyrolyzed raw material.

[0099] Next, the step of catalytically cracking the pyrolyzed raw material is carried out by subjecting the pyrolyzed raw material obtained as described above to a temperature T ２ into the downstream reaction tube heated to 525°C, and the raw material was brought into contact with the regenerated catalyst C. Two hours after the start of heating the raw material, the entire amount of the liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire amount of the gaseous catalytic cracking product was recovered in a gas bag.

[0100] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0101] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 39.0% based on the mass of the charged polyethylene.

[0102] Furthermore, the analytical values ​​of the gaseous catalytic cracking product were corrected so that the total weight of the gaseous catalytic cracking product, liquid catalytic cracking product, and residue was equal to the total weight of the raw material polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 36.8% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0103] Reference Example 2 Preparation of Zeolite Catalyst D Aluminum nitrate nonahydrate (1.15 g), 20.3 mass% tetrapropylammonium hydroxide aqueous solution (76.8 g), sodium hydroxide (0.77 g), and tetraethyl orthosilicate (64.0 g) were added to a 400 mL PTFE vessel equipped with a stirrer, and the mixture was stirred at room temperature for 18 hours to obtain a mixture. Thereafter, ion-exchanged water (56.6 g) was added to the obtained mixture, and the entire amount was transferred to an SUS autoclave equipped with a 200 mL PTFE cylindrical vessel.

[0104] The ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms in the mixture was 100, the ratio of the number of moles of tetrapropylammonium hydroxide to the number of moles of silicon atoms was 0.56, the ratio of the number of moles of sodium atoms to the number of moles of silicon atoms was 0.06, and the ratio of the number of moles of water to the number of moles of silicon atoms was 13.

[0105] The mixture was heated in an autoclave at 170°C for 24 hours and then cooled with ice water. After cooling, the mixture (suspension) in the cylindrical container was centrifuged and the supernatant was removed to obtain a zeolite precursor.

[0106] Water was added to the obtained zeolite precursor to form a suspension again, and the supernatant was removed by centrifugation. This procedure was repeated until the pH of the supernatant became 8 or less, to obtain a solid.

[0107] The obtained solid was dried at 120° C. for 8 hours, pulverized in a mortar, and then calcined at 550° C. for 7 hours in a muffle furnace to obtain Zeolite 2 (13.6 g).

[0108] Zeolite 2 (6.0 g) and 0.5 M ammonium nitrate aqueous solution (300 mL) were added to a 500 mL resin container and allowed to stand for 6 hours at a temperature of 60° C. Thereafter, the resulting mixture was subjected to suction filtration using a Buchner funnel to recover the solid.

[0109] The recovered solid and 0.5 M aqueous ammonium nitrate solution (300 mL) were added to a flask, and the mixture was allowed to stand for 12 hours at a temperature of 60° C. Thereafter, the resulting mixture was subjected to suction filtration using a Buchner funnel to recover the solid.

[0110] The recovered solid and 0.5 M aqueous ammonium nitrate solution (300 mL) were added to a flask, and the mixture was allowed to stand for 6 hours at 60° C. Thereafter, the resulting mixture was subjected to suction filtration using a Buchner funnel to recover the solid.

[0111] The recovered solid was washed with water (500 mL) and dried at 90° C. for 6 hours, and then calcined in a muffle furnace at 550° C. for 5 hours in an air atmosphere to obtain zeolite 3 (4.6 g).

[0112] The obtained zeolite 3 (4.5 g) and 0.1 M aqueous sodium nitrate solution (450 mL) were placed in a two-necked 500 mL glass recovery flask equipped with a condenser, and the mixture was allowed to stand for 2 hours at 100° C. Thereafter, the obtained mixture was subjected to suction filtration using a Buchner funnel to recover the solid.

[0113] The recovered solid and 0.1 M aqueous sodium nitrate solution (450 mL) were added to the recovery flask and allowed to stand at 100°C for 2 hours. The resulting mixture was then suction filtered using a Buchner funnel to recover the solid. The recovered solid was washed with water (300 mL) and dried at 110°C for 12 hours.

[0114] The resulting solid was calcined in an air atmosphere at 550° C. for 5 hours using a muffle furnace to obtain a powdery zeolite catalyst D (4.1 g).

[0115] Zeolite catalyst D was analyzed by ICP atomic emission spectroscopy, and the sodium atom content was found to be 0.24 mass%, and the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms (Si / Al ratio) was 85. Furthermore, zeolite catalyst D was analyzed by X-ray diffraction analysis, and it was confirmed that it had an MFI structure.

[0116] Comparative Example 1 Production of Olefins The upstream reaction tube of two glass reaction tubes connected in series was packed with a raw material (weight ratio of LDPE:PVC=95:5) which was a mixture of polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.425 g) and organochlorine compound polyvinyl chloride (PVC) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Shin-Etsu PVC Straight Polymer TK-1000) (0.075 g), and the downstream reaction tube was packed with zeolite catalyst D (0.3 g).

[0117] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0118] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the zeolite catalyst D, and then the temperature of the downstream reaction tube was lowered to 525°C.

[0119] The step of pyrolyzing the raw material was carried out by passing nitrogen gas at a flow rate of 10 NmL / min and setting the temperature of the electric furnace in the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material. ２ The raw material was introduced into the downstream reaction tube at 525°C, and the raw material was brought into contact with the zeolite catalyst D.

[0120] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0121] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0122] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 19.8% based on the mass of the charged polyethylene.

[0123] Furthermore, the analytical value of the gaseous catalytic cracker was corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 25.2% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0124] Finally, the spent zeolite catalyst (spent zeolite catalyst E) was recovered.

[0125] Comparative Example 2 Regeneration of Spent Zeolite Catalyst E (Preparation of Regenerated Catalyst F) Spent zeolite catalyst E was calcined in an air atmosphere using a muffle furnace at a temperature of 550° C. for 5 hours to obtain regenerated catalyst F.

[0126] Comparative Example 3 Production of Olefins Using Regenerated Catalyst F Two glass reaction tubes were connected in series. The upstream reaction tube was filled with polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.0 g) as a raw material, and the downstream reaction tube was filled with regenerated catalyst F (0.2 g).

[0127] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0128] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the regenerated catalyst F, and then the temperature of the downstream reaction tube was lowered to 525°C. The step of thermally decomposing the raw material was carried out by passing nitrogen gas through the upstream reaction tube at a flow rate of 10 NmL / min, while setting the electric furnace temperature of the upstream reaction tube to 455°C, thereby obtaining a thermally decomposed raw material. In the step of catalytically decomposing the thermally decomposed raw material, the raw material obtained as described above was heated to a temperature T ２into the downstream reaction tube at 525°C, and the raw material was brought into contact with the regenerated catalyst F.

[0129] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0130] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0131] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 26.2% based on the mass of the charged polyethylene.

[0132] Furthermore, the analytical values ​​of the gaseous catalytic cracker were corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 30.8% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0133] <Reference Example 3> Preparation of Zeolite Catalyst G Aluminum nitrate nonahydrate (0.30 g), 22.3 mass% tetrapropylammonium hydroxide aqueous solution (76.8 g), sodium hydroxide (0.79 g), and tetraethyl orthosilicate (63.4 g) were added to a 400 mL PTFE container equipped with a stirrer, and the mixture was stirred at room temperature for 18 hours to obtain a mixture. Thereafter, ion-exchanged water (56.4 g) was added to this mixture, and the entire amount was transferred to a stainless steel (SUS) autoclave equipped with a 200 mL PTFE inner cylindrical container.

[0134] In the mixture, the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms was 400, the ratio of the number of moles of tetrapropylammonium hydroxide to the number of moles of silicon atoms was 0.56, the ratio of the number of moles of sodium atoms to the number of moles of silicon atoms was 0.06, and the ratio of the number of moles of water to the number of moles of silicon atoms was 13.

[0135] The mixture was heated in an autoclave at 170°C for 24 hours and then cooled with ice water. After cooling, the mixture (suspension) in the cylindrical container was centrifuged and the supernatant was removed to obtain a zeolite precursor.

[0136] Water was added to the obtained zeolite precursor to form a suspension again, and the suspension was centrifuged and the supernatant was removed. This procedure was repeated until the pH of the supernatant became 8 or less, thereby forming a solid again.

[0137] The obtained solid was dried at 120° C. for 8 hours, pulverized in a mortar, and then calcined in a muffle furnace at 550° C. for 6 hours to obtain Zeolite 4 (12.5 g).

[0138] Zeolite 4 (10.0 g) and 0.5 M aqueous ammonium nitrate solution (500 mL) were added to a 500 mL resin container and allowed to stand for 6 hours at 60° C. The resulting mixture was then subjected to suction filtration using a Buchner funnel to recover the solid.

[0139] The recovered solid and 0.5 M aqueous ammonium nitrate solution (500 mL) were added to a flask, and the mixture was allowed to stand for 6 hours at 60° C. Thereafter, the resulting mixture was subjected to suction filtration using a Buchner funnel to recover the solid.

[0140] Next, the recovered solid and 0.5 M ammonium nitrate aqueous solution (500 mL) were added to a flask and allowed to stand at 60° C. for 6 hours. The resulting mixture was then suction filtered using a Buchner funnel to recover the solid. The recovered solid was washed with water (750 mL) and dried at 90° C. for 12 hours to obtain a solid.

[0141] The obtained solid was calcined in an air atmosphere at a temperature of 550° C. for 5 hours using a muffle furnace to obtain a powdery zeolite catalyst G (7.3 g).

[0142] Zeolite catalyst G was analyzed by ICP atomic emission spectroscopy, and the sodium atom content was found to be 0.03 mass%, and the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms (Si / Al ratio) was 576. Furthermore, zeolite catalyst G was analyzed by X-ray diffraction analysis, and it was confirmed that it had an MFI structure.

[0143] Example 4 Production of Olefins The upstream reaction tube of two glass reaction tubes connected in series was packed with a raw material (weight ratio of LDPE:PVC=95:5) which was a mixture of polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.425 g) and organochlorine compound polyvinyl chloride (PVC) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Shin-Etsu PVC Straight Polymer TK-1000) (0.075 g), and the downstream reaction tube was packed with zeolite catalyst G (0.3 g).

[0144] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0145] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the zeolite catalyst G, and then the temperature of the downstream reaction tube was lowered to 525°C.

[0146] The step of pyrolyzing the raw material was carried out by passing nitrogen gas at a flow rate of 10 NmL / min and setting the temperature of the electric furnace in the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material. ２ The raw material was introduced into the downstream reaction tube at 525°C, and the raw material was brought into contact with the zeolite catalyst G.

[0147] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0148] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0149] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 37.0% based on the mass of the charged polyethylene.

[0150] Furthermore, the analytical values ​​of the gaseous catalytic cracker were corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 38.8% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0151] Finally, the spent zeolite catalyst (spent zeolite catalyst H) was recovered.

[0152] Example 5 Regeneration of Spent Zeolite Catalyst H (Preparation of Regenerated Catalyst I) Spent zeolite catalyst H was calcined in an air atmosphere at a temperature of 550°C for 5 hours using a muffle furnace to obtain regenerated catalyst I.

[0153] Example 6 Production of Olefins Using Regenerated Catalyst I The upstream reaction tube of two glass reaction tubes connected in series was filled with polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.0 g) as a raw material, and the downstream reaction tube was filled with regenerated catalyst I (0.2 g).

[0154] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0155] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the regenerated catalyst I, and then the temperature of the downstream reaction tube was lowered to 525°C. The step of pyrolyzing the raw material was carried out by passing nitrogen gas through the upstream reaction tube at a flow rate of 10 NmL / min and setting the electric furnace temperature of the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material.

[0156] The step of catalytically cracking the thermally cracked raw material comprises: ２ into the downstream reaction tube at 525°C, and the raw material was brought into contact with the regenerated catalyst I.

[0157] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0158] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0159] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 37.5% based on the mass of the charged polyethylene.

[0160] Furthermore, the analytical values ​​of the gaseous catalytic cracker were corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 38.6% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0161] Reference Example 4 Preparation of Zeolite Catalyst J Aluminum nitrate nonahydrate (0.122 g), 20.3 mass% tetrapropylammonium hydroxide aqueous solution (76.8 g), sodium hydroxide (0.77 g), and tetraethyl orthosilicate (64.0 g) were added to a 400 mL PTFE vessel equipped with a stirrer, and the mixture was stirred at room temperature for 18 hours to obtain a mixture. Ion-exchanged water (56.6 g) was then added to the mixture, and the entire amount was transferred to a stainless steel (SUS) autoclave equipped with a 200 mL PTFE cylindrical vessel.

[0162] In the mixture, the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms was 1000, the ratio of the number of moles of tetrapropylammonium hydroxide to the number of moles of silicon atoms was 0.56, the ratio of the number of moles of sodium atoms to the number of moles of silicon atoms was 0.06, and the ratio of the number of moles of water to the number of moles of silicon atoms was 13.

[0163] The mixture was heated in an autoclave at 170°C for 24 hours and then cooled with ice water. After cooling, the mixture (suspension) in the cylindrical container was centrifuged and the supernatant was removed to obtain a zeolite precursor.

[0164] Water was added to the obtained zeolite precursor to form a suspension again, and the suspension was centrifuged and the supernatant was removed. This procedure was repeated until the pH of the supernatant became 8 or less, thereby forming a solid again.

[0165] The obtained solid was dried at 120° C. for 8 hours, pulverized in a mortar, and then calcined in a muffle furnace at 550° C. for 7 hours to obtain zeolite 5 (14.2 g).

[0166] Zeolite 5 (6.6 g) and 0.5 M aqueous ammonium nitrate solution (300 mL) were added to a 500 mL resin container and allowed to stand for 5 hours at 60° C. The resulting mixture was then suction filtered using a Buchner funnel, and the recovered solid was dried at 90° C. for 1 hour.

[0167] The dried solid and 0.5 M aqueous ammonium nitrate solution (330 mL) were added to a flask, and the mixture was allowed to stand for 6 hours at 60° C. Thereafter, the resulting mixture was subjected to suction filtration using a Buchner funnel to collect the solid.

[0168] Next, the recovered solid and 0.5 M ammonium nitrate aqueous solution (330 mL) were added to a flask and allowed to stand at 60° C. for 12 hours. The resulting mixture was then suction filtered using a Buchner funnel to recover the solid. The recovered solid was washed with water (500 mL) and dried at 90° C. for 6 hours to obtain a solid.

[0169] The obtained solid was calcined in an air atmosphere at 550° C. for 5 hours using a muffle furnace to obtain a powdery zeolite catalyst J (5.5 g).

[0170] Zeolite catalyst J was analyzed by ICP atomic emission spectrometry, and the sodium atom content was found to be less than 0.01 mass%, which is the lower detection limit, and the ratio of the number of moles of silicon atoms to the number of moles of aluminum atoms (Si / Al ratio) was 1249. Furthermore, zeolite catalyst J was analyzed by X-ray diffraction analysis, and it was confirmed that it had an MFI structure.

[0171] Example 7 Production of Olefins The upstream reaction tube of two glass reaction tubes connected in series was packed with a raw material (weight ratio of LDPE:PVC=95:5) which was a mixture of polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.425 g) and organochlorine compound polyvinyl chloride (PVC) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Shin-Etsu PVC Straight Polymer TK-1000) (0.075 g), and the downstream reaction tube was packed with zeolite catalyst J (0.3 g).

[0172] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0173] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the zeolite catalyst J, and then the temperature of the downstream reaction tube was lowered to 525°C.

[0174] The step of pyrolyzing the raw material was carried out by passing nitrogen gas at a flow rate of 10 NmL / min and setting the temperature of the electric furnace in the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material. ２ The raw material was introduced into the downstream reaction tube at 525°C, and the raw material was brought into contact with the zeolite catalyst J.

[0175] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0176] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0177] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 31.2% based on the mass of the charged polyethylene.

[0178] Furthermore, the analytical values ​​of the gaseous catalytic cracker were corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 34.5% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0179] Finally, the spent zeolite catalyst (spent zeolite catalyst K) was recovered.

[0180] Example 8 Regeneration of Spent Zeolite Catalyst K (Preparation of Regenerated Catalyst L) Spent zeolite catalyst K was calcined in an air atmosphere using a muffle furnace at a temperature of 550° C. for 5 hours to obtain regenerated catalyst L.

[0181] Example 9 Production of Olefins Using Regenerated Catalyst L Two glass reaction tubes were connected in series. The upstream reaction tube was filled with polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.0 g) as a raw material, and the downstream reaction tube was filled with regenerated catalyst L (0.2 g).

[0182] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0183] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the regenerated catalyst L, and then the temperature of the downstream reaction tube was lowered to 525°C. The step of pyrolyzing the raw material was carried out by passing nitrogen gas through the upstream reaction tube at a flow rate of 10 NmL / min and setting the electric furnace temperature of the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material.

[0184] The step of catalytically cracking the thermally cracked raw material comprises: ２ into the downstream reaction tube at 525°C, and the raw material was brought into contact with the regenerated catalyst L.

[0185] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0186] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0187] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 29.8% based on the mass of the charged polyethylene.

[0188] Furthermore, the analytical value of the gaseous catalytic cracker was corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw material polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 33.2% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0189] Example 10 Production of Olefins The upstream reaction tube of two glass reaction tubes connected in series was packed with a raw material (weight ratio of LDPE:PVC=99.5:0.5) which was a mixture of polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (0.9805 g) and organochlorine compound polyvinyl chloride (PVC) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Shin-Etsu PVC Straight Polymer TK-1000) (0.0052 g), and the downstream reaction tube was packed with zeolite catalyst A (0.2 g).

[0190] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0191] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the zeolite catalyst A, and then the temperature of the downstream reaction tube was lowered to 525°C.

[0192] The step of pyrolyzing the raw material was carried out by passing nitrogen gas at a flow rate of 10 NmL / min and setting the temperature of the electric furnace in the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material. ２ The raw material was introduced into the downstream reaction tube at 525°C, and the raw material was brought into contact with the zeolite catalyst A.

[0193] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0194] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0195] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 34.3% based on the mass of the charged polyethylene.

[0196] Furthermore, the analytical values ​​of the gaseous catalytic cracker were corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 40.5% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0197] Finally, the spent zeolite catalyst (spent zeolite catalyst M) was recovered.

[0198] Example 11 Regeneration of Spent Zeolite Catalyst M (Preparation of Regenerated Catalyst N) Spent zeolite catalyst M was calcined in an air atmosphere using a muffle furnace at a temperature of 550° C. for 5 hours to obtain regenerated catalyst N.

[0199] Example 12 Production of Olefins Using Regenerated Catalyst N Two glass reactors were connected in series. The upstream reactor was filled with 0.82 g of polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F), a polyolefin, as a raw material, and the downstream reactor was filled with 0.16 g of regenerated catalyst N.

[0200] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0201] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the regenerated catalyst N, and then the temperature of the downstream reaction tube was lowered to 525°C. The step of pyrolyzing the raw material was carried out by passing nitrogen gas through the upstream reaction tube at a flow rate of 10 NmL / min and setting the electric furnace temperature of the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material.

[0202] The step of catalytically cracking the thermally cracked raw material comprises: ２ into the downstream reaction tube at 525°C, and the raw material was brought into contact with the regenerated catalyst N.

[0203] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0204] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0205] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 35.0% based on the mass of the charged polyethylene.

[0206] Furthermore, the analytical values ​​of the gaseous catalytic cracker were corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 41.5% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0207] Example 13 Production of Olefins The upstream reaction tube of two glass reaction tubes connected in series was packed with a raw material (weight ratio of LDPE:PVC=90:10) which was a mixture of polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (0.135 g) and organochlorine compound polyvinyl chloride (PVC) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Shin-Etsu PVC Straight Polymer TK-1000) (0.015 g), and the downstream reaction tube was packed with zeolite catalyst A (0.3 g).

[0208] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0209] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the zeolite catalyst A, and then the temperature of the downstream reaction tube was lowered to 525°C.

[0210] The step of pyrolyzing the raw material was carried out by passing nitrogen gas at a flow rate of 10 NmL / min and setting the temperature of the electric furnace in the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material. ２ The raw material was introduced into the downstream reaction tube at 525°C, and the raw material was brought into contact with the zeolite catalyst A.

[0211] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0212] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0213] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 30.3% based on the mass of the charged polyethylene.

[0214] Furthermore, the analytical value of the gaseous catalytic cracker was corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw material polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 39.7% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0215] Finally, the spent zeolite catalyst (spent zeolite catalyst O) was recovered.

[0216] Example 14 Regeneration of Spent Zeolite Catalyst O (Preparation of Regenerated Catalyst P) Spent zeolite catalyst O was calcined in an air atmosphere at a temperature of 550° C. for 5 hours using a muffle furnace to obtain a regenerated catalyst P.

[0217] Example 15 Production of Olefins Using Regenerated Catalyst P Two glass reaction tubes were connected in series. The upstream reaction tube was filled with polyolefin polyethylene (LDPE) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikathene G201F) (1.0 g) as a raw material, and the downstream reaction tube was filled with regenerated catalyst P (0.2 g).

[0218] A cooling trap was connected further downstream of the downstream reaction tube, and a 5 L gas bag was connected downstream of the cooling trap.

[0219] Nitrogen gas was passed through the upstream reaction tube at a flow rate of 10 NmL / min, and only the downstream reaction tube was heated at 550°C for 1 hour to pretreat the regenerated catalyst P, and then the temperature of the downstream reaction tube was lowered to 525°C. The step of pyrolyzing the raw material was carried out by passing nitrogen gas through the upstream reaction tube at a flow rate of 10 NmL / min and setting the electric furnace temperature of the upstream reaction tube to 455°C, thereby obtaining a pyrolyzed raw material.

[0220] The step of catalytically cracking the thermally cracked raw material comprises: ２ into the downstream reaction tube at 525°C, and the raw material was brought into contact with the regenerated catalyst P.

[0221] Two hours after the start of heating the raw materials, the entire liquid catalytic cracking product obtained was recovered in a cooling trap cooled with ice water, and the entire gaseous catalytic cracking product was recovered in a gas bag.

[0222] The weights of the recovered liquid catalytic cracking product and the residues adhering to the upstream and downstream reaction tubes were measured using a balance.

[0223] The recovered gaseous catalytic cracking product was analyzed by gas chromatography, and the yield of olefins having 2 to 3 carbon atoms was found to be 32.8% based on the mass of the charged polyethylene.

[0224] Furthermore, the analytical value of the gaseous catalytic cracker was corrected so that the total weight of the gaseous catalytic cracker, liquid catalytic cracker, and residue was equal to the total weight of the raw material polyethylene and PVC. As a result, the yield of olefins having 2 to 3 carbon atoms was calculated to be 42.8% based on the mass of the charged polyethylene. The results are also shown in Table 1.

[0225]

Claims

1. A method for producing an olefin, comprising a step of catalytically cracking a raw material containing at least a polyolefin and an organic chlorine compound in the presence of a zeolite catalyst having a sodium atom content of less than 0.1% by mass.

2. The method for producing an olefin according to claim 1, wherein the zeolite catalyst is an MFI-type zeolite catalyst.

3. The method for producing an olefin according to claim 1 or 2, wherein the Si / Al ratio of the zeolite catalyst is 100 or more.

4. The method for producing an olefin according to claim 1 or 2, wherein the Si / Al ratio of the zeolite catalyst is 300 or more.

5. The method for producing an olefin according to claim 1, wherein the olefin is an olefin having 2 to 3 carbon atoms.

6. The method for producing an olefin according to any one of claims 1 to 5, wherein the sodium atom content of the zeolite catalyst is less than 0.05% by mass.

7. The method for producing an olefin according to any one of claims 1 to 6, wherein the organic chlorine compound contains at least one of polyvinyl chloride and polyvinylidene chloride.

8. The method for producing an olefin according to claim 7, wherein the chlorine atom content in the raw material is 10% by mass or less.

9. The method for producing an olefin according to any one of claims 1 to 8, further comprising a step of thermally decomposing the raw material before the step of catalytically cracking the raw material.

10. The method for producing an olefin according to any one of claims 1 to 9, further comprising a step of vaporizing the raw material before the step of catalytically cracking the raw material, and the step of catalytically cracking the raw material is a step of catalytically cracking the gaseous raw material.

11. The method for producing an olefin according to any one of claims 1 to 10, wherein the step of catalytically cracking is carried out at 450°C or higher and 600°C or lower.

12. The method for producing an olefin according to any one of claims 1 to 11, wherein the zeolite catalyst is a regenerated catalyst.

13. A method for regenerating a catalyst, comprising a step of firing a used zeolite catalyst used in the method for producing an olefin according to any one of claims 1 to 11 in an atmosphere containing 1% to 50% by volume of oxygen to obtain a regenerated catalyst.

14. A method for producing an olefin, comprising a step of catalytically cracking a raw material containing a polyolefin in the presence of a regenerated catalyst regenerated by the regeneration method according to claim 13.