Method for producing olefins

Abstract

The present invention provides a catalytic cracking catalyst that exhibits high activity even when containing carbon. [Solution] A catalytic cracking catalyst according to one aspect of the present invention contains zeolite and carbon. The zeolite contains hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, as well as atoms of one or more elements selected from alkali metal elements, alkaline earth metal elements, and transition metal elements, in a specific proportion. 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.

Description

Technical Field

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

Background Art

[0002] Olefins, which are the main raw materials for plastics, are usually produced from petroleum. However, recently, technologies for producing olefins from waste plastics have been developed in order to achieve a carbon recycling society. For example, Patent Document 1 discloses a method for producing olefins by thermally decomposing and catalytically decomposing polyolefins as raw materials. In this document, the catalyst used for catalytic decomposition is MFI-type zeolite.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The catalytic decomposition catalyst described in Patent Document 1 and the like decreases in activity due to the adhesion of carbon such as coke during continuous use.

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

Means for Solving the Problems

[0006] The catalytic decomposition catalyst according to one aspect of the present invention is a catalytic decomposition catalyst containing zeolite and carbon, wherein the zeolite comprises hydrogen atoms, oxygen atoms, aluminum atoms and silicon atoms, It includes 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. The above 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: 1. Hold the above catalytic decomposition catalyst in air at 150°C for 15 minutes; 2. Heat up to 800℃; 3. Measure the weight loss from the start of heating to the end of heating.

[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 having the following step S1, Process S1: A process of firing a material containing zeolite and carbon-containing material; The above zeolite is, Hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, It includes 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. The firing conditions in step S1 described above are as follows: Manufacturing method: Firing temperature: 550~850℃; Baking time: 1-25 minutes. [Effects of the Invention]

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

[0009] [Figure 1]It is a flowchart showing an example of a method for manufacturing a catalytic cracking catalyst according to one aspect of the present invention. [Figure 2] It is a flowchart showing an example of a method for manufacturing an olefin according to one aspect of the present invention. [Figure 3] It is a block diagram showing an implementation example of a method for manufacturing an olefin according to one aspect of the present invention. [Figure 4] It is a flowchart showing an example in which the flow of FIG. 2 is incorporated into the production of olefins from plastics. [Figure 5] It is a block diagram showing an example in which the block of FIG. 3 is incorporated into the production of olefins from plastics.

Mode for Carrying Out the Invention

[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. Each component will be described in detail below. <目标文本: <目标文本:

[0011] <目标文本: [1.1. Carbon] The catalytic cracking catalyst contains carbon. In one embodiment, the catalytic cracking catalyst may be a regenerated catalytic cracking catalyst that has undergone a regeneration treatment to reduce the carbon content from a catalyst that has been used in a catalytic cracking reaction at least once. 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. Coke can be derived from materials and products of catalytic cracking and the like. As an example, coke is produced by firing materials and products of catalytic cracking and the like.

[0012] When the catalytic cracking catalyst is subjected to thermogravimetric measurement, the weight loss is 0.01% by weight or more, and can be 0.03% by weight or more, 0.05% by weight or more, or 0.08% by weight or more, based on the weight of the entire catalytic cracking catalyst. When the catalytic cracking catalyst is subjected to thermogravimetric measurement, the weight loss is 1.5% by weight or less, and can be 1.4% by weight or less or 1.3% by weight or less, based on the weight of the entire catalytic cracking catalyst. Since carbon such as coke burns when heated at a high temperature, the value of the weight loss by thermogravimetric measurement can be considered as the amount of carbon contained in the catalytic cracking catalyst.

[0013] Here, the procedure for thermogravimetric measurement for measuring the weight loss is as follows. For an example of a more specific measurement procedure, refer to the examples of the present application. 1. Hold the catalytic cracking catalyst at 150°C for 15 minutes in air. 2. Heat up to 800°C. 3. Measure the weight loss from the start of heating to the end of heating.

[0014] According to the common general knowledge in the art, the carbon contained in the catalytic cracking catalyst does not participate in the mechanism of catalytic cracking. Similarly, according to the common general knowledge in the art, the catalytic cracking catalyst that has become carbon-containing due to continuous use has a reduced catalytic activity. Therefore, those skilled in the art would expect that the less the amount of carbon contained in the catalytic cracking catalyst, the more preferable it should be. However, according to what the inventors have found, surprisingly, the catalytic activity of the catalytic cracking catalyst is improved when it contains a small amount of carbon. This is an unexpected result contrary to 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° can 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. Zeolite] 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, NH4 + -ZSM-5, Na + -ZSM-5, Ca 2+ -ZSM-5 is an example. In one embodiment, the zeolite is NH4 + -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 manufacturing zeolite] The zeolite contained in the catalytic cracking catalyst can be produced by conventional methods. Zeolite 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, morpholine, 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 number of moles of the mold agent, alkali metal source, and water contained in the mixture before crystallization is preferably within the following range, with the number of moles of silicon atoms being 1. • Mold agent: 0.02 or higher or 0.05 or higher; 5.0 or lower or 2.0 or lower • Alkali metal source: 0.01 or higher or 0.04 or higher; 0.3 or lower or 0.2 or lower 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, 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 Ingredients] 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-tria, silica-magnesia, silica-gyronia, silica-beryllia, and ternary compositions of silica and other refractory oxides. Examples of binders (matrix materials) include viscous materials (montmorillonite, kaolin, bentonite, halloysite, dickite, nacrite, anaxite, etc.). In the catalytic cracking catalyst, the weight percentage of zeolite may be 50% or more by weight, 70% or more by weight, or 90% or more by weight. In one embodiment, the catalytic cracking catalyst does not contain components other than zeolite and carbon.

[0037] [2. Method for producing catalytic cracking catalysts] One aspect of the present invention is a method for producing a catalytic cracking catalyst. The method for producing a catalytic cracking catalyst will be described below with reference to the illustrative Figure 1. In the production method shown in Figure 1, a catalytic cracking catalyst is produced through steps S0 and S1. Of these, step S0 is an optional step and may or may not be performed.

[0038] [2.1. Process S0: Catalytic cracking of hydrocarbons by zeolite] In step S0, hydrocarbons are catalytically cracked using zeolite. The specific details of step S0 will be explained in detail as step S13 in Section 3.3, so they will not be described 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. Since the components constituting the zeolite do not usually change before and after catalytic cracking, the zeolite after 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 (materials for catalytic cracking), hydrocarbon decomposition products (products of catalytic cracking), and coke (residue of catalytic cracking) adhere to the zeolite. Thus, the zeolite, after being used as a catalytic cracking catalyst, contains carbon-containing substances and can therefore be used as a material in step S1. Step S0 may be a step in which hydrocarbons are catalytically cracked using a new zeolite catalyst, or it may be a step in which hydrocarbons are catalytically cracked using a regenerated zeolite catalyst.

[0041] [2.2. Process S1: Baking of materials] In step S1, a material containing zeolite and a carbon-containing substance is calcined. By adjusting the calcination conditions within a specific range, a catalytic cracking catalyst with high catalytic activity can be obtained. The material in step S1 may be zeolite obtained after use as a catalytic cracking catalyst in step S0, or it may be another material. In one embodiment, step S1 is a regeneration step for the zeolite catalyst after use 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 usually does not change before and after calcination, 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 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 for it.

[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 a method for producing olefins according to one embodiment of the present invention, with reference to illustrative Figures 2 and 4. In the production method shown in Figure 2, olefins are 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). The following describes each step in detail.

[0056] [3.1. Process S11: Pretreatment] In process S11, the plastic is pre-treated. The pre-treated 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: Pyrolysis] 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 gaseous, liquid, or a mixture 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 process 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 may 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). Examples of indirect heating include a method in which heat obtained by an electric heater or combustion is supplied via the heat transfer surface of the device, a method in which high-temperature gas (such as steam, nitrogen gas, or CO2 gas) is introduced into the device, or a method in which high-temperature solid particles (mainly composed of iron, iron oxide, alumina, silica, etc.) are introduced into the device. For preheating the gas or solid particles introduced into the device, the same device used in process S12 may be used, or a device combined with the device used in process S12 may be used. The gas or solid particles introduced into the device 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 -80kPaG or higher, -10kPaG or higher, or 0kPaG or higher. The gauge pressure may be 1000kPaG or lower, 300kPaG or lower, or 100kPaG or lower.

[0064] In step S12, a catalyst may be used to promote thermal decomposition. An example of a catalyst used is a silicate catalyst. Silicate catalysts typically contain silicon atoms, aluminum atoms, oxygen atoms, and hydrogen atoms. Silicate catalysts may also 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, and gallium atoms. In one embodiment, the silicate catalyst is a zeolite. In one embodiment, the zeolite is an MFI-type zeolite. The zeolite may be the zeolite described in Section 1.2.

[0065] Step S12 may be carried out in the presence or absence of a carrier gas. A carrier gas is a gas introduced into the reaction system to fluidize the decomposition products. The carrier gas may be introduced in step S12, or in a step prior to step S12. On the other hand, the gases generated in steps S12 and S13 are not included in the carrier gas. Examples of carrier gases include inert gases (such as nitrogen gas and argon gas), water vapor, and CO2 gas. In one embodiment, the carrier gas is nitrogen gas and / or water vapor.

[0066] The flow rate of the carrier gas can be adjusted as appropriate so that the concentration of hydrocarbons in the first product P1 sent to step S13 is within an appropriate range. 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 hydrocarbons 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, when the weight of hydrocarbons sent to step S13 is taken as 1.

[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 higher, 2.0 NmL / g·min or higher, or 3.0 NmL / g·min or higher. 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 lower, 50 NmL / g·min or lower, or 25 NmL / g·min or lower.

[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 process S13 may be -80kPaG or higher, -10kPaG or higher, or 0kPaG or higher. The gauge pressure may be 1000kPaG or lower, 300kPaG or lower, or 100kPaG 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 the 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 fewer 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 substances 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. This configuration can further improve the yield of olefins.

[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 comprises 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 pyrolysis unit 21, a catalytic cracking 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 is connected to the pyrolysis unit 21 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 is connected to the supply port of the catalytic cracking unit 22 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 is 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 a gas. 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 secondary 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, The above zeolite is, Hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, It includes 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. The above 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: 1. Hold the above catalytic decomposition catalyst in air at 150°C for 15 minutes; 2. Heat up to 800℃; 3. Measure the weight loss from the start of heating to the end of heating. <2> A method for producing a catalytic cracking catalyst having the following step S1, Process S1: A process of firing a material containing zeolite and carbon-containing material; The above zeolite is, Hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, It includes 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. The firing conditions in step S1 described above are as follows: Manufacturing method: Firing temperature: 550~850℃; Baking time: 1-25 minutes. <3> The above carbon-containing substance includes one or more selected from the group consisting of hydrocarbons, hydrocarbon decomposition products, and coke. <2> A method for producing the catalytic cracking catalyst described above. <4> Prior to the above step S1, the following step S0 is performed: <2> or <3> Method for producing the catalytic cracking catalyst described above: Process S0: A process in which hydrocarbons are catalytically decomposed using the zeolite described above. <5> The above step S1 is carried out in the presence of oxygen. <2> ~ <4> A method for producing a catalytic cracking catalyst as described in any of the following. <6> The above process S1 is carried out in the presence of water vapor. <5> A method for producing the catalytic cracking catalyst described above. <7> A method for producing olefins, comprising the following step S13: Process S13: <1> The catalytic cracking catalyst described above or <2> ~ <6> A step of catalytically cracking hydrocarbons with a catalyst obtained by a manufacturing method described in any of the above. <8> Prior to the above step S13, the following step S12 is performed: <7> Method for producing the olefin described above: Step S12: A step of obtaining the above hydrocarbons by thermally decomposing a polyolefin-containing raw material. <9> The total content of polyethylene and polypropylene in the above-mentioned polyolefin-containing raw material is 50% by weight or more, based on the weight of the polyolefin-containing raw material. <8> A method for producing the olefin described above.

[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, the numerical range "A~B" is intended to mean "greater than or equal to A, and less than or equal to B". [Examples]

[0090] [Measurement method] (1)Catalytic activity The activity of the catalytic cracking catalysts in the examples and comparative examples was evaluated according to the following procedure. 1. Two SUS316 reaction tubes were prepared and connected in series. 1.0 g of the catalytic cracking catalyst according to 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. While circulating nitrogen gas from the upstream side of the pellet feeder (flow rate: 45 NmL / min), the temperature of the upstream reaction tube was raised 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). Under these conditions, polyethylene (Sumikasen G201F, Sumitomo Chemical Co., Ltd.) was supplied to the upstream reaction tube (supply rate: 0.25 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. 5. Of the catalytic decomposition products obtained within 40 minutes of the start of polyethylene supply, liquid products were collected using a cooling trap, and gaseous products were collected using a gas bag. 6. The gaseous catalytic cracking products were analyzed by GC-FID, and the yield of olefins with 2 to 5 carbon atoms was determined. The yield is expressed relative to the weight of polyethylene used as raw material.

[0091] (2) Weight reduction 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 obtained in this experiment is considered to correspond to the amount of carbon (such as coke) contained in the catalytic cracking catalyst. 1. The Themo Plus Evo2 (Rigaku Corporation) was prepared as the measuring instrument. 2. The catalyst according to the example or comparative example was placed in an Al2O3 pan and heated to 150°C at a heating rate of 15°C / min, and then held for 15 minutes. This process was carried out under the flow of dry air (flow rate: 500 mL / min). 3. Heating rate: The temperature was raised to 800°C at a 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, aluminum, and sodium atoms in the zeolite were measured using inductively coupled plasma mass spectrometry (ICP-MS). An Agilent 5110 VDV (Agilent Technologies) was used for the measurements.

[0093] (4) XRD analysis of carbon contained 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 the majority 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 on it was mounted in the instrument and measured. The instrument used was the MiniFlex 600 (Rigaku Corporation). The measurement range 2θ = 0 to 70°. This range sufficiently covered the major peaks required for crystal structure analysis of typical 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 = 26-27° was expressed with the height of the peak appearing around 2θ = 7.9° set to 100%. 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 NH4 + -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 using the following procedure. 1. Using a muffle furnace, NH4 + -MFI (CBV28014, Zeolyst, 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). Catalyst A was obtained in this way. 2. Two SUS316 reaction tubes were prepared and connected in series. The downstream reaction tube was filled with 16g of catalyst A. 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 the upstream side of the pellet feeder (flow rate: 45 NmL / min), the temperature of the upstream reaction tube was raised 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). Under these conditions, 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 to cool the system. 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 circulating nitrogen from the upstream end of the reaction tube (flow rate: 100 NmL / min). 9. The gas flowing through the reaction tube was changed to a mixture of nitrogen and dry air (total flow rate: 100 NmL / min). The oxygen concentration in the gas mixture was 10% by volume. Under these conditions, 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 NmL / 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 related to Examples 2-6 and Comparative Example 1.

[0096] [Comparative Example 2] Catalyst B in Example 1 was used as the catalytic cracking catalyst in Comparative Example 2.

[0097] 〔result〕 Table 1-1 shows the calcination conditions for the materials and the physical properties of the resulting catalysts. Table 1-2 shows the elemental content of the zeolite (CBV28014) used in the examples or comparative examples. This elemental content does not change throughout the process of the examples or comparative examples. [Table 1] JPEG2026111368000003.jpg33155

[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 in the example showed a higher yield of olefins by catalytic cracking than the catalyst in the comparative example. This result is surprising. Previously, it was thought that the presence of carbon in a catalytic cracking catalyst reduced its catalytic activity (comparative example 2 supports this), and that the less carbon there was, the better. However, as shown in this example, reducing the amount of carbon in the catalytic cracking catalyst too much also reduced the catalytic activity (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 to prevent the amount of carbon contained from becoming too low. A manufacturing method according to one aspect of the present invention satisfies these appropriate calcination conditions. [Industrial applicability]

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

Claims

1. A catalytic cracking catalyst containing zeolite and carbon, The above zeolite is, Hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, It contains 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. The above 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:

1. Hold the above catalytic decomposition catalyst in air at 150°C for 15 minutes; 2. Heat up to 800°C; 3. Measure the weight loss from the start of heating to the end of heating.

2. A method for producing a catalytic cracking catalyst having the following step S1, Step S1: A step of firing a material containing zeolite and carbon-containing material; The above zeolite is, Hydrogen atoms, oxygen atoms, aluminum atoms, and silicon atoms, It contains 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. The firing conditions in step S1 described above are as follows: Manufacturing method: Firing temperature: 550-850°C; Baking time: 1 to 25 minutes.

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

4. A method for producing a catalytic cracking catalyst according to claim 2, comprising the following step S0 prior to step S1: Process S0: A process of catalytically decomposing hydrocarbons using the zeolite described above.

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

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

7. A method for producing an olefin, comprising the following step S13: Step S13: A step of catalytically cracking a hydrocarbon using 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 obtaining the above hydrocarbon by thermally decomposing a polyolefin-containing raw material.

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

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