Zeolite composition and method for producing same or method for producing olefin using same

Abstract

Provided is a catalytic cracking catalyst that has high activity even when containing carbon. The catalytic cracking catalyst of the present disclosure contains zeolite and carbon. The zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, and also contains atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements, and transition metal elements, in specific proportions. The weight loss of the catalytic cracking catalyst in thermogravimetry is 0.01-1.5 wt % based on the weight of the catalytic cracking catalyst.

Description

Zeolite composition and method for producing the same, or method for producing olefins using the same

[0001] This invention relates to a zeolite composition and a method for producing the same, or a method for producing an olefin using the same.

[0002] Olefins, the main raw material for plastics, are typically manufactured using petroleum as a raw material. However, in recent years, technologies have been developed to produce olefins from waste plastics, with the aim of realizing a carbon-recycling society. For example, Patent Document 1 discloses a method for producing olefins by thermal decomposition and catalytic decomposition of polyolefins, which are the raw materials. In this document, the catalyst used for catalytic decomposition is an MFI-type zeolite.

[0003] International Publication No. 2021 / 166854

[0004] Catalytic cracking catalysts, such as those described in Patent Document 1, experience a decrease in activity due to the accumulation of carbon such as coke with continuous use.

[0005] One aspect of the present invention aims to provide a catalytic cracking catalyst that has high activity even when it contains carbon.

[0006] A catalytic cracking catalyst according to one aspect of the present invention is a catalytic cracking catalyst containing zeolite and carbon, wherein the zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms and silicon atoms, and atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements and transition metal elements, the total content of the alkali metal elements, alkaline earth metal elements and transition metal elements is 0.001 to 0.1% by weight based on the weight of the zeolite, and the catalytic cracking catalyst exhibits a weight loss of 0.01 to 1.5% by weight based on the weight of the catalytic cracking catalyst as determined by the following procedure: 1. Hold the catalytic cracking catalyst in air at 150°C for 15 minutes; 2. Increase the temperature to 800°C; 3. Measure the weight loss from the start to the end of the temperature increase.

[0007] A method for producing a catalytic cracking catalyst according to another aspect of the present invention is a method for producing a catalytic cracking catalyst comprising the following step S1: Step S1: A step of calcining a material containing zeolite and a carbon-containing substance; The zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms and silicon atoms, and atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements and transition metal elements, and the total content of the alkali metal elements, alkaline earth metal elements and transition metal elements is 0.001 to 0.1% by weight based on the weight of the zeolite, and the calcination conditions in step S1 are as follows: Manufacturing method: Calcination temperature: 550 to 850°C; Calcination time: 1 to 25 minutes.

[0008] According to one aspect of the present invention, a catalytic cracking catalyst that has high activity even when containing carbon can be provided.

[0009] This is a flow chart showing an example of a method for producing a catalytic cracking catalyst according to one aspect of the present invention. This is a flow chart showing an example of a method for producing an olefin according to one aspect of the present invention. This is a block diagram showing an implementation example of a method for producing an olefin according to one aspect of the present invention. This is a flow chart showing an example of incorporating the flow of Figure 2 into the production of an olefin from plastic. This is a block diagram showing an example of incorporating the block of Figure 3 into the production of an olefin from plastic.

[0010] [1. Catalytic Cracking Catalyst] One aspect of the present invention is a catalytic cracking catalyst that can be used for catalytic cracking of hydrocarbons and the like. The catalytic cracking catalyst contains zeolite and carbon. The following describes each component in detail.

[0011] [1.1. Carbon] Catalytic cracking catalysts contain carbon. In one embodiment, the catalytic cracking catalyst may be a regenerated catalytic cracking catalyst, which is obtained by regenerating a catalyst that has been used in a catalytic cracking reaction at least once and has had its carbon content reduced. When the catalytic cracking catalyst is a regenerated catalytic cracking catalyst, carbon is usually contained in the form of coke. In one embodiment, carbon contains coke or consists of coke. The coke may originate from the materials or products of the catalytic cracking. For example, the coke may be produced by the calcination of the materials or products of the catalytic cracking.

[0012] The weight loss of a catalytic cracking catalyst measured by thermogravimetric analysis is 0.01% by weight or more, and may be 0.03% by weight or more, 0.05% by weight or more, or 0.08% by weight or more, relative to the total weight of the catalytic cracking catalyst. The weight loss of a catalytic cracking catalyst measured by thermogravimetric analysis is 1.5% by weight or less, and may be 1.4% by weight or less, or 1.3% by weight or less, relative to the total weight of the catalytic cracking catalyst. Since carbon in coke and other materials burns when heated at high temperatures, the weight loss measured by thermogravimetric analysis can be considered to represent the amount of carbon contained in the catalytic cracking catalyst.

[0013] The procedure for thermogravimetric analysis to measure weight loss is as follows. For a more specific example of the measurement procedure, please refer to the embodiment of this application. 1. Hold the catalytic decomposition catalyst in air at 150°C for 15 minutes. 2. Increase the temperature to 800°C. 3. Measure the weight loss from the start to the end of the heating process.

[0014] According to common technical knowledge in this field, the carbon contained in catalytic cracking catalysts does not participate in the catalytic cracking mechanism. Similarly, according to common technical knowledge, catalytic cracking catalysts that have become carbon-containing due to continuous use will experience a decrease in catalytic activity. Therefore, those skilled in the art would expect that the less carbon contained in the catalytic cracking catalyst, the better. However, the inventors have found that, surprisingly, the catalytic activity of the catalytic cracking catalyst improves when it contains a small amount of carbon. This is a surprising result that goes against the expectations of those skilled in the art.

[0015] The carbon contained in catalytic cracking catalysts is usually amorphous. Therefore, in the XRD spectrum of catalytic cracking catalysts, the peak intensity originating from graphite is usually small. In the XRD spectrum of catalytic cracking catalysts, the height of the peak appearing in the region 2θ = 26–27° may be 25% or less, 15% or less, 10% or less, or 5% or less of the height of the largest peak originating from zeolite. The peak appearing in the region 2θ = 26–27° is a peak originating from the (0,0,3) plane of rhombohedral graphite or the (0,0,2) plane of hexagonal graphite. If two or more peaks appear in this region, the higher peak should be compared with the peak originating from zeolite.

[0016] [1.2. Zeolites] Catalytic cracking catalysts contain zeolites. Zeolites contain hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms. Zeolites further contain atoms of one or more elements selected from the group consisting of alkali metal elements, alkaline earth metal elements, and transition metal elements. Alkali metal elements are metallic elements belonging to Group 1 of the periodic table. Examples include lithium, sodium, potassium, rubidium, cesium, and francium. Alkaline earth metal elements are metallic elements belonging to Group 2 of the periodic table. Examples include beryllium, magnesium, calcium, strontium, barium, and radium. Transition metal elements are metallic elements belonging to Groups 3 through 11 of the periodic table. Examples include scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, lanthanum and lanthanides, hafnium, tungsten, rhenium, osmium, iridium, platinum, gold, actinium and actinides.

[0017] Zeolites may also contain atoms such as boron, nitrogen, phosphorus, zinc, and gallium, in addition to the elements mentioned above.

[0018] The total content of alkali metal elements, alkaline earth metal elements, and transition metal elements contained in the zeolite is 0.001% by weight or more, and may be 0.003% by weight or more, or 0.005% by weight or more, based on 100% by weight of the zeolite. The total content of alkali metal elements, alkaline earth metal elements, and transition metal elements contained in the zeolite is 0.1% by weight or less, and may be 0.08% by weight or less, or 0.06% by weight or less, based on 100% by weight of the zeolite. In one embodiment, the zeolite contains sodium, and the above numerical ranges are the numerical ranges of the sodium content contained in the zeolite. The amount of elements contained in the zeolite is measured by inductively coupled plasma emission spectrometry. For more specific examples of measurement methods, please refer to the embodiments of this application.

[0019] Examples of zeolites include beta-type zeolite, faujasite-type zeolite, L-type zeolite, ferrielite-type zeolite, mordenite-type zeolite, and MFI-type zeolite.

[0020] In one embodiment, the zeolite includes or consists of MFI-type zeolite. MFI-type zeolite refers to a crystalline aluminosilicate having an MFI structure according to the structural code of IZA (International Zeolite Association), and is also called ZSM-5. A specific example of MFI-type zeolite is H ＋ -ZSM-5, NH ４ ＋ -ZSM-5, Na ＋ -ZSM-5, Ca ２＋ -ZSM-5 is an example. In one embodiment, the zeolite is NH ４ ＋ -ZSM-5.

[0021] The molar ratio of aluminum atoms to silicon atoms in the zeolite (Si / Al ratio) can be 10 or more, 40 or more, 50 or more, 100 or more, or 300 or more. The Si / Al ratio can be 10,000 or less, 2,500 or less, 1,000 or less, 800 or less, or 500 or less. If the Si / Al ratio falls within the above range, the yield of olefins tends to improve. The Si / Al ratio can be determined by ICP emission spectrometry.

[0022] [1.2.1. Method for Producing Zeolites] Zeolites contained in catalytic cracking catalysts can be produced by conventional methods. Zeolites can be produced by crystallizing a mixture containing a silicon source, an aluminum source, a mold agent, and a specific element source (alkali metal source, alkaline earth metal source, and / or transition metal source). Here, the mold agent is a substance that forms a pore structure in crystalline aluminosilicate.

[0023] The silicon source may be a conventionally known silica-containing material used in the production of zeolites. Specific examples of silica-containing materials include tetraethyl orthosilicate, colloidal silica, silica gel powder, silica hydrogel, and sodium silicate.

[0024] The aluminum source may be any conventionally known aluminum source used in the production of zeolites. Specific examples of aluminum sources include aluminum nitrate, aluminum chloride, aluminum hydroxide, sodium aluminate, and aluminum alkoxide. Among these aluminum sources, aluminum nitrate and sodium aluminate are preferred.

[0025] The mold agent may be any conventionally known mold agent used in zeolite synthesis. Specific examples of mold agents include tetrapropylammonium salt, tetraethylammonium salt, tetrabutylammonium salt, benzyltrimethylammonium salt, propanolamine, ethanolamine, n-propylamine, morpholin, 1,5-diaminopentane, 1,6-diaminohexane, dipropylenetetramine, and triethylenetetramine. Among these mold agents, tetrapropylammonium salt is preferred.

[0026] Examples of alkali metal sources include alkali metal-containing hydroxides, alkali metal-containing chlorides, alkali metal-containing bromides, and alkali metal-containing sulfides.

[0027] When the alkali metal is sodium, the sodium source is a sodium-containing compound. Examples of sodium-containing compounds include those containing sodium as a countercation. More specifically, these include sodium hydroxide, sodium chloride, sodium bromide, sodium sulfate, sodium silicate, and sodium aluminate.

[0028] When the alkali metal is potassium, the potassium source is a potassium-containing compound. Examples of potassium-containing compounds include those containing potassium as a countercation. More specifically, these include potassium hydroxide, potassium chloride, potassium bromide, potassium sulfate, potassium silicate, and potassium aluminate.

[0029] Examples of alkaline earth metal sources include salts containing alkaline earth metals. Specific examples of alkaline earth metal sources include magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium carbonate, magnesium acetate, calcium chloride, calcium sulfate, calcium nitrate, calcium carbonate, and calcium acetate.

[0030] Examples of transition metal sources include salts containing transition metals. Specific examples of transition metal sources include silver chloride, silver sulfate, silver nitrate, silver acetate, silver bromide, copper chloride, copper sulfate, copper nitrate, copper carbonate, copper acetate, rhodium chloride, rhodium sulfate, and rhodium nitrate.

[0031] The moles of the mold agent, alkali metal source, and water contained in the mixture before crystallization are preferably within the following ranges, with the number of moles of silicon atoms being 1: • Mold agent: 0.02 or more or 0.05 or more; 5.0 or less or 2.0 or less • Alkali metal source: 0.01 or more or 0.04 or more; 0.3 or less or 0.2 or less • Water: 2 or more or 5 or more; 100 or less or 50 or less

[0032] Zeolite can be prepared by crystallizing the above-mentioned mixture in a sealed pressure vessel. The reaction temperature is, for example, 100°C to 200°C. The reaction time is, for example, 1 to 120 hours. The zeolite obtained by crystallization is usually washed and then dried. The drying temperature is, for example, 100°C to 150°C. The drying time is, for example, 1 to 48 hours. The dried zeolite may be further calcined. The calcination temperature is, for example, 300°C to 700°C. The calcination time is, for example, 1 to 48 hours.

[0033] Crystallized zeolites may contain large amounts of specific elements (alkali metals, alkaline earth metals, and / or transition metals). In such cases, the content of these specific elements may be reduced. For example, the content of specific elements (such as alkali metals) can be reduced by bringing the zeolite into contact with an aqueous solution of ammonium salt.

[0034] Examples of ammonium salts include ammonium salts of inorganic acids (ammonium sulfate, ammonium hydrogen sulfate, ammonium carbonate, ammonium bicarbonate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate, ammonium hydrogen pyrophosphate, ammonium pyrophosphate, ammonium chloride, ammonium nitrate, etc.) and ammonium salts of organic acids (ammonium acetate, etc.). Among these, ammonium sulfate, ammonium chloride, and ammonium nitrate are preferred.

[0035] Specifically, the presence of certain elements can be reduced by mixing an aqueous solution of ammonium salt with zeolite. The mixing temperature is, for example, 50°C to 200°C. The mixing time is, for example, 1 to 48 hours. The zeolite, from which the alkali metal source has been reduced, is usually washed and then dried. The drying temperature is, for example, 60°C to 150°C. The dried zeolite may be further calcined. The calcination temperature is, for example, 300°C to 700°C.

[0036] [1.3. Other Components] The catalytic cracking catalyst may contain components other than zeolite and carbon. Examples of such components include carriers and binders (matrix materials). Examples of carriers include silica, alumina, silica-alumina, silica-titania, silica-thoria, silica-magnesia, silica-zirconia, silica-beryllia, and ternary compositions of silica and other refractory oxides. Examples of binders (matrix materials) include clays (montmorillonite, kaolin, bentonite, halloysite, dickite, nacrite, anaxite, etc.). In the catalytic cracking catalyst, the weight ratio occupied by zeolite can be 50% by weight or more, 70% by weight or more, or 90% by weight or more. In one embodiment, the catalytic cracking catalyst does not contain components other than zeolite and carbon.

[0037] [2. Method for Producing Catalytic Cracking Catalyst] One aspect of the present invention is a method for producing a catalytic cracking catalyst. Hereinafter, the method for producing the catalytic cracking catalyst will be described while referring to exemplary FIG. 1. In the production method shown in FIG. 1, the catalytic cracking catalyst is produced through Step S0 and Step S1. Among these, Step S0 is an optional step and may or may not be carried out.

[0038] [2.1. Step S0: Catalytic Cracking of Hydrocarbons by Zeolite] In Step S0, hydrocarbons are catalytically cracked by zeolite. Since the specific details of Step S0 will be described in detail as Step S13 in Section 3.3, the description will be omitted in this section.

[0039] The zeolite used in step S0 may be the zeolite described in section 1.2. That is, the composition of the zeolite may satisfy the following conditions. Usually, since the components constituting the zeolite do not change before and after catalytic cracking, the zeolite after passing through step S0 may also satisfy the following conditions. - It contains hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms. - It further contains atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements, and transition metal elements. - The total content of alkali metal elements, alkaline earth metal elements, and transition metal elements is 0.001 to 0.1% by weight based on the weight of the zeolite.

[0040] In step S0, carbon-containing substances such as hydrocarbons which are materials for catalytic cracking, hydrocarbon decomposition products which are products of catalytic cracking, and coke which is a residue of catalytic cracking adhere to the zeolite. Thus, since the zeolite after being used as a catalytic cracking catalyst contains carbon-containing substances, it can be used as a material for step S1. Step S0 may be a step of catalytically cracking hydrocarbons using a new zeolite catalyst, or may be a step of catalytically cracking hydrocarbons using a zeolite catalyst subjected to regeneration treatment.

[0041] [2.2. Step S1: Firing of materials]In step S1, a material containing zeolite and carbon-containing substances is fired. By adjusting the firing conditions at this time within a specific range, a catalytic cracking catalyst with high catalytic activity can be obtained. The material in step S1 may be the zeolite after being used as a catalytic cracking catalyst obtained through step S0, or may be other materials. In one embodiment, step S1 is a regeneration step of a zeolite catalyst after being used as a catalytic cracking catalyst.

[0042] The zeolite contained in the material in step S1 satisfies the following conditions. Such zeolite may be the zeolite described in Section 1.2. Since the composition of zeolite does not usually change before and after firing, the zeolite contained in the catalytic cracking catalyst obtained through step S1 may also satisfy the following conditions: - It contains hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms. - It further contains atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements, and transition metal elements. - The total content of alkali metal elements, alkaline earth metal elements, and transition metal elements is 0.001 to 0.1% by weight, based on the weight of the zeolite.

[0043] In one embodiment, the carbon-containing substance included in the material in step S1 is one or more selected from the group consisting of hydrocarbons, hydrocarbon decomposition products, and coke. Such a carbon-containing substance may be attached to the zeolite via step S0, or it may be of another origin.

[0044] The carbon-containing substance content in the material may be 0.01 parts by weight or more, or 0.05 parts by weight or more, when the total weight of zeolite and carbon-containing substance is 100 parts by weight. The carbon-containing substance content in the material may be 1.5 parts by weight or less, or 1.0 part by weight or less, when the weight of zeolite is 100 parts by weight.

[0045] The firing temperature in step S1 is 550°C or higher, and may be 570°C or higher or 600°C or higher. The firing temperature in step S1 is 850°C or lower, and may be 830°C or lower or 800°C or lower.

[0046] The baking time in step S1 is 1 minute or more, and may be 3 minutes or more or 5 minutes or more. The baking time in step S1 is 25 minutes or less, and may be 23 minutes or less or 20 minutes or less.

[0047] In step S1, the material may be fired in the presence of oxygen. The oxygen concentration during firing may be 1% by volume or more, 3% by volume or more, or 5% by volume or more. The oxygen concentration during firing may be 25% by volume or less, 23% by volume or less, or 20% by volume or less. The oxygen concentration can be adjusted by the concentration of oxygen gas contained in the firing atmosphere.

[0048] In step S1, the material may be fired in the presence of water vapor. The water vapor concentration during firing may be 0.1% by volume or more, 0.5% by volume or more, or 1.0% by volume or more. The water vapor concentration during firing may be 50% by volume or less, 30% by volume or less, or 10% by volume or less. The water vapor concentration can be adjusted by the concentration of water vapor gas contained in the firing atmosphere.

[0049] The oxygen or water vapor concentration can be controlled by adjusting the concentration of oxygen gas or water vapor in the firing atmosphere. Examples of atmospheres include air, nitrogen gas, argon gas, carbon dioxide gas, and mixtures thereof.

[0050] The catalytic cracking catalyst obtained through step S1 may be the catalyst described in Section 1, and it does not need to satisfy one or more of the conditions.

[0051] In one embodiment, the catalytic cracking catalyst obtained through step S1 contains zeolite and carbon. In one embodiment, the weight loss of the catalytic cracking catalyst in thermogravimetric analysis is 0.01 to 1.5% by weight, based on the weight of the catalytic cracking catalyst. The procedure for thermogravimetric analysis is as described in Section 1.

[0052] [3. Method for Producing Olefins] One aspect of the present invention is a method for producing olefins using a catalytic cracking catalyst. In one embodiment, the catalytic cracking catalyst is the catalytic cracking catalyst described in Section 1. In one embodiment, the catalytic cracking catalyst is obtained by the production method described in Section 2.

[0053] The following describes an olefin production method according to one embodiment of the present invention with reference to illustrative Figures 2 and 4. In the production method shown in Figure 2, an olefin is produced from hydrocarbons through steps S12 and S13. Of these, step S12 is an optional step and may or may not be performed. The method by which the hydrocarbons supplied to step S13 are generated is not particularly limited.

[0054] Figure 4 shows an example of implementing the flow chart in Figure 2 for the production of olefins by decomposing plastics. In the production method shown in Figure 4, olefins are produced from plastics through steps S11, S12, S13, and S14. Of these, steps S11, S12, and S14 are optional steps and may or may not be performed.

[0055] According to this manufacturing method, polyolefins are decomposed to obtain an olefin-rich gas that is rich in olefins (particularly lower olefins with 2 to 5 carbon atoms). Each step is described in detail below.

[0056] [3.1. Process S11: Pretreatment] In process S11, the plastic is pretreated. The pretreated plastic becomes a feed material M (polyolefin-containing raw material) mainly containing polyolefins, and is sent to process S12. The plastic supplied to process S11 is, for example, waste plastic and contains polyolefins (polyethylene, polypropylene, etc.). When comparing the plastic supplied to process S11 with the feed material M sent to process S12, the latter usually has a higher polyolefin content.

[0057] The polyolefin content in the plastic supplied to process S11 may be 60% by weight or more, 80% by weight or more, or 90% by weight or more, based on 100% by weight of the total amount of plastic. The polyolefin content in the feed M may be 80% by weight or more, 90% by weight or more, or 95% by weight or more, based on 100% by weight of the total amount of feed M. The total content of polyethylene and polypropylene in feed M may be 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more, based on 100% by weight of the total amount of feed M.

[0058] [3.2. Step S12: Thermal Decomposition] In step S12, the feed material M is thermally decomposed. The first product P1 obtained by thermal decomposition mainly contains hydrocarbons and is sent to step S13. The number of carbon atoms in the hydrocarbons contained in the first product P1 may be 1 to 30. The average number of carbon atoms in the hydrocarbons contained in the first product P1 may be 8 to 30. The hydrocarbons contained in the first product P1 may be gases, liquids, or mixtures thereof. In one embodiment, a further step may be provided after step S12 to liquefy the gaseous hydrocarbons before sending them to step S13.

[0059] In one embodiment, the hydrocarbon contained in the first product P1 includes one or more selected from the group consisting of normal paraffins, cycloparaffins, isoparaffins, olefins, cycloolefins, and isoolefins.

[0060] The thermal decomposition temperature in step S12 may be set based on the composition of the feed material M. A higher thermal decomposition temperature results in a faster decomposition rate of the plastic, but if it is too high, it will carbonize. Taking this into consideration, the thermal decomposition temperature may be 800°C or lower, 595°C or lower, or 550°C or lower. The thermal decomposition temperature may be 350°C or higher, 380°C or higher, or 400°C or higher.

[0061] At least a portion of the heat source required in step S12 may be supplied by combustion. Examples of fuels used in combustion include the pyrolysis residue in step S12, a hydrocarbon-containing liquid and / or lower paraffin gas in step S14, and fuels introduced from outside the system (natural gas, kerosene, etc.). Alternatively, at least a portion of the heat source required in step S12 may be supplied by electric heating or microwave irradiation.

[0062] The heating method can be either direct heating or indirect heating. An example of direct heating is a method in which microwave energy is directly supplied to the supply M via a microwave-absorbing material (susceptor). An example of indirect heating is a method in which heat obtained by an electric heater or combustion is supplied via the heat transfer surface of the device, or by using a high-temperature gas (water vapor, nitrogen gas, CO2). ２ Methods include introducing gases or other substances into the apparatus, and introducing heated solid particles (mainly composed of iron, iron oxide, alumina, silica, etc.) into the apparatus. For preheating the gases or solid particles introduced into the apparatus, the same apparatus used in process S12 may be used, or an apparatus combined with the apparatus used in process S12 may be used. The gases or solid particles introduced into the apparatus may be circulated.

[0063] In step S12, a low pressure is desirable because the number of moles increases due to the thermal decomposition reaction. The gauge pressure in step S12 may be -80 kPaG or higher, -10 kPaG or higher, or 0 kPaG or higher. The gauge pressure may be 1000 kPaG or lower, 300 kPaG or lower, or 100 kPaG or lower.

[0064] In step S12, a catalyst may be used to promote pyrolysis. Examples of the catalyst to be used include silicate catalysts. Silicate catalysts usually contain silicon atoms, aluminum atoms, oxygen atoms, and hydrogen atoms. Silicate catalysts may contain atoms such as sodium atoms, 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, gallium atoms, etc. In one embodiment, the silicate catalyst is zeolite. In one embodiment, the zeolite is MFI-type zeolite. The zeolite may be the zeolite described in Section 1.2.

[0065] Step S12 may be carried out in the presence of a carrier gas or in the absence of a carrier gas. The carrier gas represents a gas introduced into the reaction system to flow the decomposition products. A carrier gas may be introduced in step S12, or a carrier gas may be introduced in a step prior to step S12. On the other hand, the gas generated in step S12 or step S13 is not included in the carrier gas. Examples of the carrier gas include inert gases (such as nitrogen gas and argon gas), water vapor, and CO ２ gas. In one embodiment, the carrier gas is nitrogen gas and / or water vapor.

[0066] The flow rate of the carrier gas can be appropriately adjusted so that the concentration of hydrocarbons in the first product P1 sent to step S13 is within an appropriate range. When the weight of the hydrocarbon sent to step S13 is taken as 1, the weight of the carrier gas sent to step S13 may be 0.05 or more, 0.1 or more, or 0.15 or more. When the weight of the hydrocarbon sent to step S13 is taken as 1, the weight of the carrier gas sent to step S13 may be 1 or less, 0.75 or less, or 0.5 or less.

[0067] In the embodiment where step S12 is carried out using a fluidized bed reactor, the greater the amount of fluidized gas, the lower the hydrocarbon concentration in the gas phase, and therefore the easier it is for the decomposed components to vaporize. Based on this, the linear velocity of the fluidized gas in the fluidized bed reactor may be 0.1 cm / s or more, 0.5 cm / s or more, or 0.8 cm / s or more. The linear velocity of the fluidized gas in the fluidized bed reactor may be 100 cm / s or less, 75 cm / s or less, or 20 cm / s or less.

[0068] In this embodiment, the ratio of the fluidizing gas supply rate (NmL / min) to the supply rate (g / min) of the feed M supplied to the fluidized bed reactor may be 10 NmL / g or more, 50 NmL / g or more, or 200 NmL / g or more. The ratio of the fluidizing gas supply rate (NmL / min) to the supply rate (g / min) of the feed M supplied to the fluidized bed reactor may be 2000 NmL / g or less, 1500 NmL / g or less, or 1200 NmL / g or less.

[0069] In this embodiment, the ratio of the fluidizing gas supply rate (NmL / min) to the amount of fluidizing medium (g) present in the fluidized bed reactor may be 1.0 NmL / g·min or more, 2.0 NmL / g·min or more, or 3.0 NmL / g·min or more. The ratio of the fluidizing gas supply rate (NmL / min) to the amount of fluidizing medium (g) present in the fluidized bed reactor may be 100 NmL / g·min or less, 50 NmL / g·min or less, or 25 NmL / g·min or less.

[0070] [3.3. Step S13: Catalytic Cracking] In step S13, the first product P1 is catalytically cracked in the presence of a catalytic cracking catalyst. The catalytic cracking catalyst may be one described in Section 1, or one obtained by the manufacturing method described in Section 2. The second product P2 obtained by catalytic cracking mainly contains olefins and is sent to step S14. The number of carbon atoms in the olefins contained in the second product P2 may be 2 to 5.

[0071] In one embodiment, the second product P2 contains one or more hydrocarbons selected from the group consisting of ethylene, propylene, butene, and pentene. The proportion of ethylene, propylene, butene, and pentene in the second product P2 may be 32% by weight or more, 35% by weight or more, or 40% by weight or more.

[0072] The catalytic decomposition temperature in step S13 may be set based on the composition of the first product P1. The catalytic decomposition temperature may be 400°C or higher, 450°C or higher, or 500°C or higher. The catalytic decomposition temperature may be 800°C or lower, 650°C or lower, or 600°C or lower. The heat source required for step S13 may be supplied in the same manner as in step S12.

[0073] The gauge pressure in step S13 may be -80 kPaG or higher, -10 kPaG or higher, or 0 kPaG or higher. The gauge pressure may be 1000 kPaG or lower, 300 kPaG or lower, or 100 kPaG or lower.

[0074] Step S13 may be carried out in the presence or absence of a carrier gas. The definition and examples of the carrier gas are as described in relation to step S12. The carrier gas may be introduced in step S13 or in a step prior to step S13. In one embodiment, the carrier gas is nitrogen gas and / or water vapor.

[0075] The flow rate of the carrier gas can be adjusted as appropriate so that the concentration of olefin in the second product P2 sent to step S14 is within an appropriate range. The weight of the carrier gas sent to step S14 may be 0.05 or more, 0.1 or more, or 0.15 or more, when the weight of the olefin sent to step S14 is taken as 1. The weight of the carrier gas sent to step S14 may be 1 or less, 0.75 or less, or 0.5 or less, when the weight of the olefin sent to step S14 is taken as 1.

[0076] The contact time in step S13 may be 200 seconds or more, 300 seconds or more, or 400 seconds or more. The contact time in step S13 may be 1000 seconds or less, 900 seconds or less, or 800 seconds or less. The contact time in step S13 is a value obtained by dividing the weight-based flow rate (g / sec) of the hydrocarbon supplied to step S13 by the weight (g) of the catalyst containing zeolite.

[0077] [3.4. Step S14: Purification] In step S14, the secondary product P2 is purified. In one embodiment, in step S14, the secondary product P2 is separated into olefins and other hydrocarbons (such as paraffins). In one embodiment, in step S14, olefins with a small number of carbon atoms (such as olefins with 2 to 5 carbon atoms) are separated from other hydrocarbons (such as paraffins and olefins with 6 or more carbon atoms). Step S14 separates an olefin-rich gas that is rich in olefins. The olefin content in the olefin-rich gas may be 90% by weight or more. The olefin-rich gas may contain one or more selected from the group consisting of ethylene, propylene, butene, and pentene.

[0078] At least a portion of the components other than the olefin-rich gas separated in step S14 may be refluxed to step S12 or step S13. With this configuration, the yield of olefins can be further improved.

[0079] Alternatively, at least a portion of the components other than the olefin-rich gas separated in step S14 may be burned and used as a heat source in step S12 or step S13. Such a configuration can reduce the environmental impact of the olefin manufacturing method.

[0080] [4. Olefin Manufacturing System] The olefin manufacturing method described above can be implemented by the olefin manufacturing system illustrated in Figures 3 and 5. The manufacturing system 100 shown in Figure 3 includes a thermal decomposition unit 21 and a catalytic decomposition unit 22. The two components are connected by a path L3. The raw material, supply M (polyolefin-containing raw material), is supplied from path L2.

[0081] Figure 5 shows manufacturing system 100a, an example of implementing the manufacturing system 100 shown in Figure 3 as a system for producing olefins from plastics. Manufacturing system 100a includes a pre-processing unit 10, a thermal decomposition unit 21, a catalytic decomposition unit 22, and a purification unit 30. These components are connected by paths L1 to L4.

[0082] Plastics such as waste plastics are supplied to the pre-processing unit 10 from the path L1. The discharge port of the pre-processing unit 10 and the pyrolysis unit 21 are connected by the path L2. The plastic supplied to the pre-processing unit 10 is pre-treated to become feed material M, which is supplied to the pyrolysis unit 21 via the path L2. The discharge port of the pyrolysis unit 21 and the supply port of the catalytic cracking unit 22 are connected by the path L3. The feed material M supplied to the pyrolysis unit 21 is pyrolyzed to become the first product P1, which is supplied to the catalytic cracking unit 22 via the path L3. The catalytic cracking unit 22 and the purification unit 30 are connected by the path L4. The first product P1 supplied to the catalytic cracking unit 22 is catalytically cracked to become the second product P2, which is supplied to the purification unit 30 via the path L4. The second product P2 supplied to the purification unit 30 is purified to become olefin, which is removed from the manufacturing system 100a. Each part will be described in detail below.

[0083] The pre-treatment unit 10 is a component that pre-treats plastics such as waste plastics to provide a feed material M suitable for decomposition. In other words, process S11 is carried out in the pre-treatment unit 10. The pre-treatment unit 10 may be equipped with multiple devices that perform different processes. For example, the pre-treatment unit 10 may be equipped with one or more devices selected from the group consisting of a sorting device, a crushing device, a washing device, a drying device, a melting device, and a dechlorination device. A sorting device is a device that sorts polyolefins from plastics such as waste plastics. Examples of sorting devices include optical sorting devices and specific gravity separation devices. A crushing device is a device that crushes plastics. A washing device is a device that washes plastics. A drying device is a device that dries plastics. A melting device is a device that heats plastics to make them liquid. A dechlorination device is a device that removes chlorine contained in plastics.

[0084] The pyrolysis unit 21 is a component that decomposes the feed material M by heating. In other words, process S12 is carried out in the pyrolysis unit 21. The decomposed feed material M becomes a first product P1 containing gaseous and / or liquid hydrocarbons. A further component may be provided downstream of the pyrolysis unit 21 to liquefy the first product P1, which is gaseous. The pyrolysis unit 21 may also be a device that performs pyrolysis continuously. Specific examples include an extruder, a stirring tank, a rotary kiln, and a fluidized bed. Examples of fluidized beds include an internal circulating fluidized bed and an external circulating fluidized bed. Multiple of the above-described devices may be used as the pyrolysis unit 21. Multiple devices may be connected in parallel or in series.

[0085] The catalytic cracking section 22 is a component that decomposes the first product P1 by contacting it with a catalytic cracking catalyst. In other words, step S13 is carried out in the catalytic cracking section 22. The catalytic cracking catalyst may be the catalytic cracking catalyst described in Section 1, or a catalytic cracking catalyst obtained by the manufacturing method described in Section 2. The decomposed first product P1 becomes a second product P2 containing an olefin. An example of the catalytic cracking section 22 is a reactor including a fixed bed, a moving bed, or a fluidized bed. Multiple reactors described above may be used as the catalytic cracking section 22. Multiple reactors may be connected in parallel or in series.

[0086] The purification unit 30 is a component that separates and purifies the second product P2 to obtain olefin. In other words, step S14 is carried out in the purification unit 30. Examples of the purification unit 30 include a gas-liquid separator and a distillation apparatus. Multiple of the above-mentioned apparatuses may be used as the purification unit 30. Multiple apparatuses may be connected in parallel or in series.

[0087] [5. Summary] The present invention includes the following embodiments: <1> A catalytic cracking catalyst containing zeolite and carbon, wherein the zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms and silicon atoms, and atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements and transition metal elements, the total content of the alkali metal elements, alkaline earth metal elements and transition metal elements is 0.001 to 0.1% by weight based on the weight of the zeolite, and the catalytic cracking catalyst has a weight loss of 0.01 to 1.5% by weight based on the weight of the catalytic cracking catalyst as determined by the following procedure: Catalyst: 1. Hold the catalytic cracking catalyst in air at 150°C for 15 minutes; 2. Increase the temperature to 800°C; 3. Measure the weight loss from the start to the end of the temperature increase. <2> A method for producing a catalytic cracking catalyst having the following step S1, wherein step S1: a step of calcining a material containing zeolite and a carbon-containing substance; the zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms and silicon atoms, and atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements and transition metal elements, the total content of the alkali metal elements, alkaline earth metal elements and transition metal elements is 0.001 to 0.1% by weight based on the weight of the zeolite, and the calcination conditions in step S1 are as follows: production method: calcination temperature: 550 to 850°C; calcination time: 1 to 25 minutes. <3> The method for producing a catalytic cracking catalyst according to <2>, wherein the carbon-containing substance contains one or more selected from the group consisting of hydrocarbons, hydrocarbon decomposition products and coke. <4> A method for producing a catalytic cracking catalyst according to <2> or <3>, comprising the following step S0 prior to step S1: Step S0: A step of catalytically cracking a hydrocarbon with the zeolite. <5> A method for producing a catalytic cracking catalyst according to any one of <2> to <4>, wherein step S1 is carried out in the presence of oxygen. <6> A method for producing a catalytic cracking catalyst according to <5>, wherein step S1 is carried out in the presence of water vapor.<7> A method for producing an olefin, comprising the following step S13: Step S13: A step of catalytically decomposing a hydrocarbon with the catalytic decomposition catalyst described in <1> or a catalyst obtained by any of the production methods described in <2> to <6>. <8> A method for producing an olefin according to <7>, comprising the following step S12 prior to the above step S13: Step S12: A step of thermally decomposing a polyolefin-containing raw material to obtain the above hydrocarbon. <9> A method for producing an olefin according to <8>, wherein the total content of polyethylene and polypropylene in the polyolefin-containing raw material is 50% by weight or more, based on the weight of the polyolefin-containing raw material.

[0088] The embodiments described above are examples of the present invention. However, the present invention is not limited to the above-described configurations. The present invention can be modified in various ways within the scope of the claims. The technical scope of the present invention also extends to embodiments or examples obtained by appropriately combining the multiple technical means disclosed herein. In this case, the multiple technical means may be disclosed across multiple embodiments or examples.

[0089] Unless otherwise specified in this specification, "A to B" representing a numerical range means "greater than or equal to A and less than or equal to B".

[0090] [Measurement Method] (1) Catalytic Activity The catalytic cracking catalysts of the examples and comparative examples were evaluated according to the following procedure. 1. Two SUS316 reaction tubes were prepared in series. 1.0 g of the catalytic cracking catalyst of the example or comparative example was packed into the downstream reaction tube. 2. A cooling trap was connected further downstream of the downstream reaction tube. A gas bag was connected further downstream of the cooling trap. A pellet feeder was connected further upstream of the upstream reaction tube. 3. Nitrogen gas was circulated from upstream of the pellet feeder (flow rate: 45 N mL / min) while the upstream reaction tube was heated to 450°C and the downstream reaction tube to 525°C. 4. While maintaining the temperature of the reaction tubes, water was supplied only to the downstream reaction tube (supply rate: 0.1 g / min). In this state, polyethylene (Sumikasen G201F, Sumitomo Chemical Co., Ltd.) was supplied to the upstream reaction tube (supply rate: 0.25 g / min). As a result, polyethylene was thermally decomposed in the upstream reaction tube to convert it into hydrocarbons, and the hydrocarbons were catalytically decomposed in the downstream reaction tube to convert them into olefins. 5. Of the catalytic decomposition products obtained within 40 minutes from the start of polyethylene supply, the liquid products were recovered in a cooling trap, and the gaseous products were recovered in a gas bag. 6. The gaseous catalytic decomposition products were analyzed by GC-FID, and the yield of olefins with 2 to 5 carbon atoms was determined. The yield is expressed based on the weight of polyethylene charged as raw material.

[0091] (2) Weight loss of catalyst The weight loss of the catalytic cracking catalysts in the examples and comparative examples was measured by thermogravimetric analysis using the following procedure. The weight loss in this experiment is considered to correspond to the amount of carbon (such as coke) contained in the catalytic cracking catalyst. 1. A Themo Plus Evo2 (Rigaku Corporation) was prepared as the measuring instrument. 2. The catalyst in the examples or comparative examples was subjected to Al ２ O ３ The catalyst was placed on a baking sheet and heated to 150°C at a heating rate of 15°C / min, then held for 15 minutes. This process was carried out under the flow of dry air (flow rate: 500 mL / min). 3. The catalyst was heated to 800°C at a heating rate of 10°C / min, and the weight loss in this process was determined. The weight loss is expressed relative to the weight of the catalytic cracking catalyst before the start of heating in this process.

[0092] (3) Content of specific elements in the catalyst The amounts of silicon atoms, aluminum atoms, and sodium atoms contained in the zeolite were measured by inductively coupled plasma mass spectrometry (ICP-MS). Agilent 5110 VDV (Agilent Technologies) was used for the measurements.

[0093] (4) XRD Analysis of Carbon in the Catalyst The crystalline form of carbon contained in the catalytic cracking catalysts of the examples and comparative examples was investigated using the following procedure. Since XRD peaks are caused by the crystalline structure, a low peak indicates that most of the carbon contained in the catalyst is amorphous. 1. The catalyst was placed on a glass sample plate and packed flat. 2. The sample plate with the sample was mounted in the instrument and measured. A MiniFlex 600 (Rigaku Corporation) was used as the instrument. The measurement range was set to 2θ = 0 to 70°. This range was sufficient to cover the main peaks required in the crystalline structure analysis of general zeolites and graphites. The step size was set to 0.02°. Cu Kα rays (wavelength: 1.5406 Å) were used as the X-ray source. 3. The height of the peak appearing at 2θ = 26 to 27° was expressed as 100% of the height of the peak appearing around 2θ = 7.9°. The peak appearing at 2θ = 26–27° is attributed to the (0,0,3) plane of rhombohedral graphite or the (0,0,2) plane of hexagonal graphite. The peak appearing around 2θ = 7.9° is attributed to NH ４ ＋ - This peak belongs to the (0,1,-1) plane of the MFI.

[0094] [Examples] [Example 1] The catalytic cracking catalyst according to Example 1 was manufactured by the following procedure. 1. Using a muffle furnace, NH ４ ＋- MFI (CBV28014, Zeolist, Si / Al ratio: 140) was calcined at 550°C for 5 hours. This process was carried out while supplying dry air (supply rate: 20 L / min). In this way, catalyst A was obtained. 2. Two SUS316 reaction tubes were prepared and connected in series. 16 g of catalyst A was packed into the downstream reaction tube. 3. A cooling trap was connected further downstream of the downstream reaction tube. A gas bag was connected further downstream of the cooling trap. A pellet feeder was connected further upstream of the upstream reaction tube. 4. While circulating nitrogen gas from upstream of the pellet feeder (flow rate: 45 N mL / min), the upstream reaction tube was heated to 450°C and the downstream reaction tube to 625°C. 5. While maintaining the temperature of the reaction tubes, water was supplied only to the downstream reaction tube (supply rate: 0.1 g / min). In this state, polyethylene (Sumikasen G201F, Sumitomo Chemical Co., Ltd.) was supplied to the upstream reaction tube (supply rate: 0.8 g / min). As a result, the polyethylene was thermally decomposed in the upstream reaction tube to convert it into hydrocarbons, and the hydrocarbons were catalytically decomposed in the downstream reaction tube to convert them into olefins. 6. Three hours after the start of polyethylene supply, the supply of polyethylene and water was stopped and the system was cooled. Furthermore, the flow of nitrogen gas was stopped and the catalyst was removed, which was designated as catalyst B. Catalyst B contains zeolite and a carbon-containing substance derived from hydrocarbons. 7. A portion of catalyst B was packed into another SUS316 reaction tube. 8. The temperature was raised to 600°C while nitrogen was flowed from the upstream of the reaction tube (flow rate: 100 N mL / min). 9. The gas flowing through the reaction tube was changed to a mixture of nitrogen and dry air (total flow rate: 100 N mL / min). The oxygen concentration in the mixed gas was 10 volume%. In this state, the mixture was calcined at 600°C for 10 minutes. 10. The gas flowing through the reaction tube was changed to nitrogen gas (flow rate: 100 N mL / min), and the system was cooled. The catalyst was removed and used as the catalytic cracking catalyst according to Example 1.

[0095] [Examples 2-6, Comparative Example 1] In steps 8 and 9 of Example 1, the calcination temperature, calcination time, and oxygen concentration in the mixed gas were changed as shown in Table 1-1 to obtain catalytic cracking catalysts for Examples 2-6 and Comparative Example 1.

[0096] [Comparative Example 2] Catalyst B in Example 1 was replaced with the catalytic cracking catalyst according to Comparative Example 2.

[0097] [Results] The firing conditions of the materials and the physical properties of the obtained catalysts are shown in Table 1-1. The elemental content of the zeolite (CBV28014) used in the examples or comparative examples is shown in Table 1-2. This elemental content does not change throughout the process of the examples or comparative examples.

[0098] As can be seen from Table 1-1, the catalytic cracking catalyst in the example was manufactured by the method for manufacturing a catalytic cracking catalyst according to one aspect of the present invention. As can also be seen by referring to Table 1-2, the obtained catalytic cracking catalyst also satisfied the conditions for a catalytic cracking catalyst according to one aspect of the present invention.

[0099] As can be seen from Table 1-1, the catalyst according to the example showed a higher yield of olefins by catalytic cracking than the catalyst according to the comparative example. This result is surprising. Previously, it was thought that the catalytic activity of a catalytic cracking catalyst decreased when carbon was included (comparative example 2 supports this), and that the less carbon there was, the better. However, as shown in this example, catalytic activity also decreased when the amount of carbon in the catalytic cracking catalyst was reduced too much (see comparative example 1). Therefore, when producing a catalytic cracking catalyst from a material containing zeolite and carbon-containing substances, the calcination conditions should be appropriately adjusted so that the amount of carbon contained does not become too low. The production method according to one aspect of the present invention satisfies these appropriate calcination conditions.

[0100] This invention can be used in the production of olefins and the like.

Claims

1. A catalytic cracking catalyst containing zeolite and carbon, wherein the zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, and atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements, and transition metal elements, the total content of the alkali metal elements, alkaline earth metal elements, and transition metal elements is 0.001 to 0.1% by weight based on the weight of the zeolite, and the catalytic cracking catalyst exhibits a weight loss of 0.01 to 1.5% by weight based on the weight of the catalytic cracking catalyst as determined by the following procedure:

1. Hold the catalytic cracking catalyst in air at 150°C for 15 minutes; 2. Increase the temperature to 800°C; 3. Measure the weight loss from the start to the end of the temperature increase.

2. A method for producing a catalytic cracking catalyst having the following step S1, wherein step S1: a step of calcining a material containing zeolite and a carbon-containing substance; the zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms and silicon atoms, and atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements and transition metal elements, the total content of the alkali metal elements, alkaline earth metal elements and transition metal elements is 0.001 to 0.1% by weight based on the weight of the zeolite, and the calcination conditions in step S1 are as follows: Manufacturing method: Calcination temperature: 550 to 850°C; Calcination time: 1 to 25 minutes.

3. The method for producing a catalytic cracking catalyst according to claim 2, wherein the carbon-containing substance comprises one or more selected from the group consisting of hydrocarbons, hydrocarbon decomposition products, and coke.

4. A method for producing a catalytic cracking catalyst according to claim 2, comprising the following step S0 prior to step S1: Step S0: A step of catalytically cracking a hydrocarbon with the zeolite.

5. The method for producing a catalytic cracking catalyst according to claim 2, wherein step S1 is carried out in the presence of oxygen.

6. The method for producing a catalytic cracking catalyst according to claim 5, wherein step S1 is carried out in the presence of water vapor.

7. A method for producing an olefin comprising the following step S13: Step S13: A step of catalytically cracking a hydrocarbon with the catalytic cracking catalyst described in claim 1.

8. A method for producing an olefin according to claim 7, comprising the following step S12 prior to step S13: Step S12: A step of thermally decomposing a polyolefin-containing raw material to obtain the hydrocarbon.

9. The method for producing an olefin according to claim 8, wherein the total content of polyethylene and polypropylene in the polyolefin-containing raw material is 50% by weight or more, based on the weight of the polyolefin-containing raw material.

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