Catalyst for producing light olefins and method for producing light olefins using the catalyst

Abstract

The present invention provides a catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, the catalyst having a core-shell structure including a zeolite core selected from ferrierite, ZSM-5, or a mixture thereof, and a silicalite shell having an MFI structure, and the catalyst has the following properties: a) a shell-to-core weight ratio greater than 0 but less than 4, b) a silica-to-alumina molar ratio (SiO2 / Al2O3) of 60 to 550, c) a silica-to-alumina molar ratio of 0.1 nm to 2 nm, The present invention relates to a catalyst having hierarchical pores, comprising micropores having a pore size in the range of 0.35 to 0.90, mesopores having a pore size in the range of 2 to 5 nm, and macropores having a pore size greater than 50 nm, wherein the ratio of the volume of the mesopores and macropores to the total pore volume is in the range of 0.35 to 0.90, and the mesopores include pores having a pore size of 2 to 5 nm, and the ratio of the volume of the pores having a pore size of 2 to 5 nm to the total pore volume is in the range of 0.08 to 0.30. The catalyst of the present invention provides high conversion of reactants and high selectivity, particularly for light olefins. Furthermore, the present invention also relates to a method for producing light olefins using the catalyst.

Description

[Technical Field]

[0001] The present invention relates to the field of chemistry, and more particularly to a catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, and a method for producing light olefins using the catalyst. [Background technology]

[0002] Light olefins, namely ethylene and propylene, are important reactants in the production of polymers, particularly polyethylene and polypropylene. Generally, light olefins are industrially produced by thermal steam cracking from reactants consisting of naphtha or ethane separated from natural gas. However, this method of producing light olefins is known to be energy-intensive due to the high temperatures required (800°C–900°C). Furthermore, it presents the problem of so-called coking, where large amounts of heavy hydrocarbons with more than nine carbon atoms accumulate in the system. This leads to frequent shutdowns of the production process to maintain the reactor. Therefore, alternative methods exist for producing light olefins from the catalytic cracking of naphtha. These methods offer the advantages of producing a large quantity of light olefins using lower reaction temperatures, reduced energy consumption in production, and mitigated coking problems in the system.

[0003] Zeolites are crystalline aluminosilicate compounds that possess excellent properties such as adjustable acidity-basicity depending on the reaction used, thermal and chemical stability, and shape selectivity. Therefore, zeolites are applied to a variety of processed products, including adsorbents, ion exchangers, and heterogeneous catalysts, which can function as catalysts or supports. The method of producing light olefins from catalytic cracking using zeolites as catalysts is interesting and popular because zeolites contain suitable catalytic acid moieties and possess porosity with specific properties related to the selectivity of desirable products.

[0004] The following literature discloses or reports on methods for producing light olefins from the catalytic cracking of naphtha using zeolite as a catalyst.

[0005] Patent documents 1, 2, and 3 disclose aluminosilicate or zeolite catalysts for a method of producing olefins from the catalytic cracking of naphtha-containing hydrocarbons by adding potassium, sodium, gallium, and organic ammonium cation compounds. This also included the development of catalysts which are mixtures of different types of zeolites between small-pore zeolites such as chabasite, erionite, ferrielite, and ZSM-22, and medium-pore zeolites which are nanosilicalites having a silica-to-alumina ratio greater than 200, preferably in the range of 600 to 1600.

[0006] Patent documents 4 and 5 disclose catalysts for a method of producing olefins from naphtha and hydrocarbons having 4 to 7 carbon atoms using catalysts comprising the addition of phosphorus and various zeolites having a silica-to-alumina ratio of more than 300, such as ZSM-5, ZSM-11, or mixtures thereof. This also included the development of catalysts which are mixtures of different types of zeolites between a first zeolite having a medium pore size, a second zeolite having a different structure from the first zeolite and a pore size index smaller than that of the first zeolite, and optionally a third zeolite.

[0007] Patent document 6 discloses a composition of a zeolite catalyst having a core-shell structure and a method for preparing the catalyst. The core was nano-ZSM-5, and the shell was silicalite-1 prepared from the use of tetrapropylammonium hydroxide (TPAOH) as a structure-determining agent for the zeolite.

[0008] Patent document 7 discloses a zeolite-bound zeolite catalyst composition comprising a first zeolite and a binder containing a second zeolite having a different structure from the first zeolite. The second zeolite may partially cover the first zeolite. Both zeolites may have small pore sizes in the range of 3 Å to 5 Å, medium pore sizes in the range of 5 Å to 7 Å, or large pore sizes exceeding 7 Å.

[0009] Patent document 8 discloses a method for preparing a ZSM-5 zeolite catalyst coated with silica or silicalite-1. The same document discloses a method for preparing a silica or silicalite shell coated on ZSM-5 by impregnation. Furthermore, patent document 9 discloses a method for preparing a ZSM-5 zeolite catalyst coated with silicalite-1.

[0010] Patent document 10 discloses a zeolite-bound zeolite catalyst composition comprising a first zeolite and a binder containing a second zeolite having a smaller average particle size than the first zeolite. Both zeolites may be selected from medium-pore zeolites in the range of 5 Å to less than 7 Å, large-pore zeolites greater than 7 Å, or mixtures thereof.

[0011] Patent document 11 discloses a zeolite catalyst composition comprising a first zeolite and a layer of second zeolite having a smaller average particle size than the first zeolite, covering at least a portion of the surface of the first zeolite. Both zeolites may have small pore sizes in the range of 3 Å to 5 Å, medium pore sizes in the range of 5 Å to 7 Å, or large pore sizes exceeding 7 Å.

[0012] Patent document 12 discloses a zeolite-bound zeolite catalyst composition comprising a first zeolite, a binder containing a second zeolite having a different structure from the first zeolite, and a non-zeolite binder in an amount of less than 10%. Both zeolites may have small pore sizes in the range of 3 Å to 5 Å, medium pore sizes in the range of 5 Å to 7 Å, or large pore sizes exceeding 7 Å.

[0013] Patent document 13 discloses a method for converting hydrocarbons using a zeolite-bonded zeolite catalyst comprising a core containing a first zeolite and optionally a second zeolite, and a binder containing a third zeolite and optionally a fourth zeolite, wherein at least one or both of the second zeolite and the fourth zeolite are present in an amount of 1% to 70% by weight of the catalyst. The zeolite may be selected from a small-pore zeolite in the range of 3 Å to 5 Å, a medium-pore zeolite in the range of 5 Å to 7 Å, or a large-pore zeolite greater than 7 Å.

[0014] Patent documents 14 and 15 disclose a core-shell catalyst comprising ZSM-5 zeolite as a core and a silica shell having a thickness in the range of 0.5 μm to 50 μm, and a method for preparing the catalyst using a quaternary ammonium salt as a structure-controlling agent for the zeolite. The catalyst obtained from the preparation method disclosed in the above documents was a conventional zeolite with small pore sizes predominating.

[0015] Nevertheless, using conventional zeolites as catalysts has been shown to have limitations, including low catalytic activity, rapid degradation, and difficulties and complexities in the catalyst regeneration process. This is because conventional zeolites have limitations in mass transfer and diffusion due to the pore size of the zeolite structure, which has a very small size in angstroms within the structure of large zeolite crystals, leading to critical mass transfer and making it difficult for reactant molecules to reach the active site. Furthermore, intermediates may recombine to form coke, which can lead to catalyst degradation. When conventional zeolites are used as catalysts in methods for producing light olefins from the catalytic cracking of hydrocarbons, it is found that there are still limitations in selectivity for light olefins because products are formed from side reactions at the active site on the outer surface. [Prior art documents] [Patent Documents]

[0016] [Patent Document 1] U.S. Patent No. 7981273 [Patent Document 2] U.S. Patent No. 8157985 [Patent Document 3] Specification of U.S. Patent Application Publication No. 2010 / 0105974 [Patent Document 4] U.S. Patent No. 6222087 [Patent Document 5] U.S. Patent No. 326332 [Patent Document 6] Specification of Chinese Patent Application Publication No. 107670687 [Patent Document 7] Specification of International Publication No. 1997 / 045198 [Patent Document 8] Specification of Chinese Patent Application Publication No. 113751057 [Patent Document 9] Specification of Chinese Patent Application Publication No. 113908879 [Patent Document 10] Specification of International Publication No. 1996 / 016004 [Patent Document 11] Specification of U.S. Patent Application Publication No. 2006 / 0011514 [Patent Document 12] Malaysian Registered Patent No. 120519 [Patent Document 13] [[ID=5३]] | U.S. Patent No. 6858129 [Patent Document 14] Specification of U.S. Patent Application Publication No. 2018 / 0193826 [Patent Document 15] U.S. Patent No. 10159967 [Summary of the Invention] [Problems to be Solved by the Invention]

[0017] For these reasons, the development of zeolite catalysts with hierarchical pores is important, as this is highly specific to the production of light olefins from naphtha via catalytic cracking. Considering all the literature mentioned above, it is found that there are no disclosures of core-shell zeolite catalysts having hierarchical pores including mesopores and macropores in the range of 2 nm or more, with a larger proportion of mesopores and macropores than conventional zeolites, and with different pore proportions suitable for the production of light olefins from catalytic cracking. Furthermore, some literature does not disclose the appropriate ratio of core to shell in catalysts with a core-shell structure. These are factors that affect the effectiveness of catalysts in the production of light olefins.

[0018] For the reasons stated above, the present invention aims to prepare a catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, which is suitable for use in a method for producing light olefins and provides a high conversion rate of reactants, particularly high selectivity for light olefins, and a method for producing light olefins using the catalyst. [Means for solving the problem]

[0019] The present invention relates to a catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, wherein the catalyst has a core-shell structure comprising a zeolite core selected from ferrielite, ZSM-5, or a mixture thereof, and a silicalite shell having an MFI structure, and the catalyst has the following properties: a) Shell-to-core weight ratio greater than 0 but less than 4, b) Molar ratio of silica to alumina (SiO2 / Al2O3) between 60 and 550, c) A hierarchical pore comprising micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, wherein the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.35 to 0.90, and the mesopores include pores having a pore size of 2 nm to 5 nm, and the ratio of the volume of pores having a pore size of 2 nm to 5 nm to the total pore volume is in the range of 0.08 to 0.30. The objective is to prepare a catalyst having [specific characteristics].

[0020] In another embodiment, the present invention relates to a method for producing a light olefin from catalytic cracking of a hydrocarbon having 4 to 7 carbon atoms, comprising contacting the hydrocarbon having 4 to 7 carbon atoms with a catalyst at a temperature in the range of 400°C to 700°C and a pressure in the range of 0.1 bar to 10 bar, wherein the catalyst has a core-shell structure comprising a zeolite core selected from ferrielite, ZSM-5, or a mixture thereof, and a silicalite shell having an MFI structure, and the catalyst has the following properties: a) Shell-to-core weight ratio greater than 0 but less than 4, b) Molar ratio of silica to alumina (SiO2 / Al2O3) between 60 and 550, c) A hierarchical pore comprising micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, wherein the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.35 to 0.90, and the mesopores include pores having a pore size of 2 nm to 5 nm, and the ratio of the volume of pores having a pore size of 2 nm to 5 nm to the total pore volume is in the range of 0.08 to 0.30. This relates to a method having [Brief explanation of the drawing]

[0021] [Figure 1] This figure shows the properties of the crystal structure as tested using scanning electron microscopy (SEM) technology. [Figure 2] This figure shows the pore size distribution analyzed by Barrett-Joiner-Harenda adsorption (BJH adsorption). [Figure 3] This figure shows the conversion rates of various catalysts for reactants and their selectivity for each product in the catalytic cracking of isobutane. [Figure 4] This figure shows the conversion rate of reactants and selectivity for each product of a catalyst having a core-shell structure with a ferrielite zeolite core, compared to a comparative sample catalyst, in the catalytic cracking of isobutane. [Figure 5] This figure shows the conversion rate of reactants and selectivity for each product of a catalyst with a core-shell structure, where the zeolite core is ZSM-5, compared to a comparative sample catalyst in the catalytic cracking of isobutane. [Figure 6] This figure shows the conversion rates of reactants and selectivity for each product of catalysts with manganese addition in various configurations, compared to a comparative sample catalyst, during catalytic cracking of isobutane. [Modes for carrying out the invention]

[0022] The present invention relates to a catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, which is suitable for use in a method for producing light olefins and provides a high conversion rate of reactants, particularly high selectivity for light olefins, and to a method for producing light olefins using the catalyst, which will be described in the following embodiments of the present invention.

[0023] Any aspect described herein, unless otherwise specified, includes application to other aspects of the present invention.

[0024] Unless otherwise specified, technical or scientific terms used herein have definitions that would be understood by those skilled in the art.

[0025] Any tools, apparatus, methods, or chemicals referred to herein mean tools, apparatus, methods, or chemicals that are typically used or operated by a person skilled in the art, unless otherwise specified that they are tools, apparatus, methods, or chemicals that are unique to the present invention.

[0026] The use of a singular noun or singular pronoun with “comprising” in the claims or specification means “one,” which also includes “one or more,” “at least one,” and “one or more than one.”

[0027] All compositions and / or methods disclosed in this application, and the claims, are intended to encompass embodiments from any manipulation, performance, modification, or adjustment of any factor that, even if not specifically indicated in the claims, would be materially different from the present invention and achieve a useful purpose, and yield the same results as in these embodiments, without any experimentation, as would be expected of those skilled in the art. Accordingly, any substitutable or similar objectives to these embodiments, including any minor modifications or adjustments that may be obvious to those skilled in the art, should be construed as being limited to the spirit, scope, and concept of the invention as set forth in the appended claims.

[0028] Throughout this application, the term “about” means any numerical value found or expressed herein that may vary or deviate due to any error of the instrument, method, or the person using such instrument or method, including variations or deviations resulting from changes in reaction conditions due to uncontrollable factors such as humidity and temperature. In this invention, zeolite means a microporous aluminosilicate compound containing silicon, aluminum, and oxygen in its structure. This zeolite may further contain other elements. The zeolite may be a commercially available zeolite, a natural zeolite, or a zeolite prepared by any method.

[0029] In this invention, "silicalite" refers to a zeolite compound having a polycrystalline structure in which the silica-to-alumina ratio is infinite (SiO2 / Al2O3 = ∞).

[0030] The following are embodiments of the present invention, but these are not intended to limit the scope of the invention in any way.

[0031] The present invention relates to a catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, wherein the catalyst has a core-shell structure comprising a zeolite core selected from ferrielite, ZSM-5, or a mixture thereof, and a silicalite shell having an MFI structure, and the catalyst has the following properties: a) Shell-to-core weight ratio greater than 0 but less than 4, b) Molar ratio of silica to alumina (SiO2 / Al2O3) between 60 and 550, c) A hierarchical pore comprising micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, wherein the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.35 to 0.90, and the mesopores include pores having a pore size of 2 nm to 5 nm, and the ratio of the volume of pores having a pore size of 2 nm to 5 nm to the total pore volume is in the range of 0.08 to 0.30. This relates to a catalyst having the following characteristics.

[0032] In one embodiment of the present invention, the catalyst has a hierarchical pore structure comprising micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, wherein the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.40 to 0.90, preferably in the range of 0.40 to 0.70.

[0033] In one embodiment of the present invention, the mesopores include pores having a pore size of 2 nm to 5 nm, where the ratio of the volume of pores having a pore size of 2 nm to 5 nm to the total pore volume is in the range of 0.10 to 0.20.

[0034] In one embodiment of the present invention, the mesopores further include pores having a pore size of 5 nm to 8 nm and pores having a pore size of 8 nm to 18 nm.

[0035] In one embodiment of the present invention, the mesopores further include pores having a pore size of 5 nm to 8 nm and pores having a pore size of 8 nm to 18 nm, wherein the ratio of the volume of pores having a pore size of 5 nm to 8 nm to the total pore volume is in the range of 0.05 to 0.20, preferably in the range of 0.05 to 0.15.

[0036] In one embodiment of the present invention, the mesopores further include pores having a pore size of 5 nm to 8 nm and pores having a pore size of 8 nm to 18 nm, wherein the ratio of the volume of pores having a pore size of 8 nm to 18 nm to the total pore volume is in the range of 0.05 to 0.30, preferably in the range of 0.05 to 0.20.

[0037] In one embodiment of the present invention, the zeolite core has a hierarchical pore structure including micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm.

[0038] In one embodiment of the present invention, the zeolite core has a hierarchical pore structure comprising micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, wherein the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.30 to 0.90, preferably in the range of 0.30 to 0.80.

[0039] In one embodiment of the present invention, the zeolite core has hierarchical pores and is arranged in a nanosheet-like manner.

[0040] In one embodiment of the present invention, the silica light shell has a hierarchical pore structure that includes micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm.

[0041] In one embodiment of the present invention, the silicalite shell has hierarchical pores and is arranged in a nanosheet-like manner.

[0042] In one embodiment of the present invention, the silicalite shell has an infinite molar ratio of silica to alumina.

[0043] In one embodiment of the present invention, the zeolite core has a silica-to-alumina molar ratio in the range of 35 to 320.

[0044] In one embodiment of the present invention, the zeolite core is a ferrielite having a particle arrangement resembling the shape of a flower when analyzed in SEI mode with an accelerating voltage of 20 kV using scanning electron microscopy (SEM) technology.

[0045] In one embodiment of the present invention, the catalyst has a shell-to-core weight ratio that is greater than 0 but less than or equal to 3.

[0046] In one embodiment of the present invention, the catalyst has a silica-to-alumina molar ratio in the range of 100 to 400.

[0047] In one embodiment of the present invention, the catalyst is approximately 300 m 2 / g~about 800m 2 / g, preferably about 400m 2 / g~about 700m 2 Specific surface area in the range of / g (S BET ) has.

[0048] In one embodiment of the present invention, the catalyst has an external specific surface area (S 2 ) in the range of about 50 m 2 / g to about 300 m 2 / g, preferably about 70 m 2 / g to about 250 m 2 / g, and most preferably about 80 m 2 / g to about 200 m ext .

[0049] In one embodiment of the present invention, the catalyst includes a ZSM-5 core having a molar ratio of silica to alumina in the range of 120 or more but 300 or less, and a silicalite shell, and the catalyst has a weight ratio of shell to core greater than 0 but 1.5 or less.

[0050] In one embodiment of the present invention, the catalyst includes a ZSM-5 core having a molar ratio of silica to alumina in the range of 50 or more but 120 or less, and a silicalite shell, and the catalyst has a weight ratio of shell to core greater than 0 but 3 or less.

[0051] In one embodiment of the present invention, the catalyst includes a ferrierite core having a molar ratio of silica to alumina in the range of 150 or more but 300 or less, and a silicalite shell, and the catalyst has a weight ratio of shell to core greater than 0 but 2 or less.

[0052] In one embodiment of the present invention, the catalyst includes a ferrierite core having a molar ratio of silica to alumina in the range of 50 or more but 150 or less, and a silicalite shell, and the catalyst has a weight ratio of shell to core greater than 0 but 2 or less.

[0053] In one embodiment of the present invention, the catalyst further contains manganese (Mn).

[0054] In one embodiment of the present invention, the catalyst further comprises manganese (Mn), wherein the amount of manganese is 1% to 15% by weight relative to the weight of the zeolite core. Preferably, the amount of manganese is 5% to 10% by weight relative to the weight of the zeolite core.

[0055] In one embodiment of the present invention, the zeolite core further comprises manganese (Mn). In one embodiment of the present invention, the zeolite core further comprises manganese (Mn), wherein the amount of manganese is 1% to 15% by weight relative to the weight of the zeolite core. Preferably, the amount of manganese is 5% to 10% by weight relative to the weight of the zeolite core.

[0056] In one embodiment of the present invention, the hydrocarbon is selected from butane, pentane, hexane, or heptane. Preferably, the hydrocarbon is butane, and most preferably isobutane.

[0057] In one embodiment of the present invention, the light olefin is ethylene and propylene.

[0058] In one embodiment of the present invention, the catalyst is used in a method for producing a light olefin from the catalytic cracking of a hydrocarbon having 4 to 7 carbon atoms, preferably, but not limited to, but selected from butane, having 4 carbon atoms.

[0059] In another embodiment of the present invention, a method for preparing a catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms is as follows: a) A step of preparing a mixture containing a compound for preparing a first zeolite and a first flexible structure-determining agent, and subjecting the mixture to a hydrothermal process at a specified temperature and time to convert the mixture into a zeolite, b) A step of preparing a mixture containing a compound for preparing silicalite, a second soft structure-determining agent, and the zeolite obtained from step a), and subjecting the mixture to a hydrothermal process at a specified temperature and time to convert the mixture into a zeolite having a core-shell structure, It may include.

[0060] In one embodiment of the present invention, each step of the method for preparing the catalyst may further include a calcination step at a temperature in the range of 400°C to 650°C.

[0061] In one embodiment of the present invention, the method for preparing the catalyst may further include a drying step.

[0062] Drying can be carried out by conventional drying methods using an oven, vacuum drying, agitated evaporation, and drying by rotary evaporator.

[0063] In one embodiment of the present invention, each step of the method for preparing the catalyst may further include ion exchange by contact with an ammonium salt solution.

[0064] In one embodiment of the present invention, the ammonium salt solution is selected from, but is not limited to, ammonium nitrate (NH4NO3) or ammonium hydroxide.

[0065] In one embodiment of the present invention, the compound for preparing the first zeolite is a mixture of an alumina compound selected from aluminum isopropoxide, sodium aluminate, aluminum sulfate, aluminum nitrate, or aluminum hydroxide, and a silica compound selected from tetraethyl orthosilicate (TEOS), sodium silicate, or silica gel.

[0066] In one embodiment of the present invention, the first flexible structure-determining agent is selected from pyrrolidine, a quaternary ammonium salt containing a silane group, or a quaternary ammonium salt. In one embodiment of the present invention, the quaternary ammonium salt containing a silane group may be selected from, but is not limited to, 3-(trimethoxysilyl)propyloctadecyldimethylammonium chloride (TPOAC).

[0067] In one embodiment of the present invention, the quaternary ammonium salt may be selected from, but is not limited to, tetrapropylammonium hydroxide, tetrapropylammonium bromide, or tetrabutylammonium hydroxide, as well as tetraalkylammonium salts.

[0068] In one embodiment of the present invention, the quaternary ammonium salt may further include, but is not limited to, a long-chain quaternary ammonium surfactant selected from cetyltrimethylammonium bromide (CTAB) or cetyltrimethylammonium chloride (CTAC).

[0069] In one embodiment of the present invention, the compound used to prepare the silicalite may be selected from, but is not limited to, tetraethyl orthosilicate, sodium silicate, or silica gel.

[0070] In one embodiment of the present invention, the second flexible structure-determining agent is selected from a quaternary phosphonium salt or a mixture of quaternary ammonium salts further comprising a long-chain quaternary ammonium surfactant.

[0071] In one embodiment of the present invention, the quaternary phosphonium salt is selected from tetrabutylphosphonium hydroxide (TBPOH) or tributylhexadecylphosphonium bromide.

[0072] In one embodiment of the present invention, the mixture of quaternary ammonium salts further comprises a long-chain quaternary ammonium surfactant, wherein the quaternary ammonium salt may be selected from, but is not limited to, tetrapropylammonium hydroxide, tetrapropylammonium bromide, or tetrabutylammonium hydroxide, and tetraalkylammonium salts.

[0073] In one embodiment of the present invention, the mixture of quaternary ammonium salts further comprises a long-chain quaternary ammonium surfactant, wherein the long-chain quaternary ammonium surfactant may be selected from, but is not limited to, cetyltrimethylammonium bromide (CTAB) or cetyltrimethylammonium chloride (CTAC).

[0074] In another embodiment of the present invention, the present invention relates to a method for producing a light olefin from catalytic cracking of a hydrocarbon having 4 to 7 carbon atoms, comprising contacting the hydrocarbon having 4 to 7 carbon atoms with a catalyst at a temperature in the range of 400°C to 700°C and a pressure in the range of about 0.1 bar to about 10 bar, wherein the catalyst is selected from the catalyst according to the present invention or a catalyst obtained from a method for preparing the catalyst.

[0075] In one embodiment of the present invention, contact between a hydrocarbon having 4 to 7 carbon atoms and a catalyst is carried out at a temperature in the range of 500°C to 700°C, preferably in the range of 550°C to 680°C.

[0076] In one embodiment of the present invention, contact between a hydrocarbon having 4 to 7 carbon atoms and a catalyst is carried out at a pressure in the range of about 1 bar to about 10 bar, preferably in the range of about 1 bar to about 7 bar.

[0077] In one embodiment of the present invention, the hydrocarbon is selected from butane, pentane, hexane, or heptane. Preferably, the hydrocarbon is butane, and most preferably isobutane. In one embodiment of the present invention, the products obtained from the catalytic cracking of a hydrocarbon having 4 to 7 carbon atoms are light olefins, preferably ethylene and propylene.

[0078] In one embodiment of the present invention, a method for producing light olefins from catalytic cracking may be carried out in a reactor that is not limited to a fixed-bed reactor that can be operated in a batch or continuous manner, or in a fixed-bed system, a moving-bed system, a fluidized-bed system, or a batch system.

[0079] The space velocity per second (WHSV) of the hydrocarbon supply conduit in catalytic cracking is in the range of about 1 to about 50 per hour, preferably in the range of about 1.5 to about 16 per hour.

[0080] Generally, those skilled in the art can adjust the catalytic cracking conditions of hydrocarbons having 4 to 7 carbon atoms to suit the type and composition of the feed conduit, catalyst, and reactor system.

[0081] The following embodiments illustrate only one aspect of the present invention and do not limit the scope of the invention in any way.

[0082] [Preparation of catalyst] The catalyst can be prepared by the following method.

[0083] <Preparation of ferrielite (FER) zeolite catalyst> A ferrielite zeolite catalyst was prepared by hydrothermal method using pyrrolidine as a structure-controlling agent for the zeolite, as follows.

[0084] A first solution containing sodium silicate, pyrrolidine, and water, and a second solution containing aluminum sulfate, concentrated sulfuric acid, and water were prepared. The second solution was then added dropwise to the first solution while continuously stirring. Subsequently, the resulting mixture was subjected to a hydrothermal process at a temperature of approximately 130°C to 180°C to convert the mixture into a zeolite.

[0085] Next, the obtained zeolite was washed with deionized water, dried, and calcined at a temperature of approximately 500°C to 650°C to obtain white powdered zeolite.

[0086] Subsequently, the obtained zeolite was subjected to ion exchange by contacting it with a 1 M ammonium nitrate (NH₄NO₃) solution at a temperature of about 60 °C to about 90 °C while continuously stirring. Then, this was washed with deionized water, dried, and calcined at a temperature of about 500 °C to about 600 °C to obtain a ferrierite zeolite catalyst.

[0087] <Preparation of ZSM-5 Zeolite Catalyst> The prepared product of the ZSM-5 zeolite catalyst could be prepared as follows using tetrapropylammonium hydroxide (TPAOH) as a zeolite structure-directing agent and cetyltrimethylammonium bromide (CTAB) as a hierarchical pore-forming agent by the hydrothermal method.

[0088] A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing aluminum hydroxide, tetrapropylammonium hydroxide, sodium hydroxide, cetyltrimethylammonium bromide, and water were prepared. Then, while continuously stirring, the second solution was dropped into the first solution. Thereafter, the obtained mixture was subjected to a hydrothermal process at a temperature of about 100 °C to about 180 °C to convert the mixture into zeolite.

[0089] Next, the obtained zeolite was washed with deionized water, dried, and calcined at a temperature of about 500 °C to about 650 °C to obtain a white powder zeolite.

[0090] ]>Subsequently, the obtained zeolite was subjected to ion exchange by contacting it with a 1 M ammonium nitrate (NH₄NO₃) solution at a temperature of about 60 °C to about 90 °C while continuously stirring. Then, this was washed with deionized water, dried, and calcined at a temperature of about 500 °C to about 600 °C to obtain a ZSM-5 zeolite catalyst having hierarchical pores.

[0091] <Preparation of Silicalite Catalyst> A silica-lite catalyst having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞) was prepared by hydrothermal method using tetrabutylphosphonium hydroxide (TBPOH) as a structure-controlling agent for zeolites and nanosheet structures, as follows.

[0092] A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The second solution was then added dropwise to the first solution while continuously stirring. Subsequently, the resulting mixture was subjected to a hydrothermal process at a temperature of approximately 100°C to 200°C to convert the mixture into a zeolite.

[0093] Next, the obtained zeolite was washed with deionized water, dried, and calcined at a temperature of approximately 500°C to 650°C to obtain white powdered zeolite.

[0094] Subsequently, the obtained zeolite was subjected to ion exchange by contacting it with a 1M ammonium nitrate (NH4NO3) solution at a temperature of approximately 60°C to approximately 90°C while continuously stirring. Next, it was washed with deionized water, dried, and calcined at a temperature of approximately 500°C to approximately 600°C to obtain a silicalite catalyst having hierarchical pores arranged in a nanosheet-like structure.

[0095] Preparation of ferrielite zeolite catalysts containing manganese (Mn) A ferrielite zeolite catalyst containing manganese (Mn) could be prepared by hydrothermal means using the above-mentioned ferrielite zeolite catalyst preparation process and the addition of manganese sulfate to the mixture before subjecting the mixture to the hydrothermal process.

[0096] <Preparation of catalysts having a core-shell structure> A catalyst having a core-shell structure was prepared by a hydrothermal method as follows.

[0097] A first solution and a second solution were prepared. The second solution was then added dropwise to the first solution while continuously stirring. Next, a zeolite catalyst to be used as the core was added while continuously stirring at room temperature. Subsequently, the resulting mixture was subjected to a hydrothermal process at a temperature of approximately 100°C to 200°C to convert the mixture into zeolite.

[0098] Next, the obtained zeolite was washed with deionized water, dried, and calcined at a temperature of approximately 500°C to 650°C to obtain white powdered zeolite.

[0099] Subsequently, the obtained zeolite was subjected to ion exchange by contacting it with a 1M ammonium nitrate (NH4NO3) solution at a temperature of approximately 60°C to approximately 90°C while continuously stirring. Next, it was washed with deionized water, dried, and calcined at a temperature of approximately 500°C to approximately 600°C to obtain a catalyst having a core-shell structure.

[0100] [Preparation of comparative catalysts and catalysts according to the present invention] <Comparative catalyst CAT A> The comparative catalyst CAT A could be prepared using the ferrielite zeolite catalyst preparation process described above. The comparative catalyst had a silica-to-alumina molar ratio of approximately 61.

[0101] <Comparative catalyst CAT B> The comparative catalyst CAT B could be prepared using the preparation process for the ZSM-5 zeolite catalyst described above. The comparative catalyst had a silica-to-alumina molar ratio of approximately 143.

[0102] <Comparative catalyst CAT C> The comparative catalyst CAT C could be prepared using the silica-light catalyst preparation process described above.

[0103] <Comparative catalyst CAT D> Comparative catalyst CAT D was a catalyst having a core-shell structure, where the shell was a ferrielite zeolite, and the core-shell structure had a shell-to-core weight ratio of approximately 1. Comparative catalyst CAT D could be prepared using the preparation process for catalysts having the core-shell structure described above. Pyrrolidine was used as a structure-controlling agent for the zeolite. A first solution containing sodium silicate, pyrrolidine, and water, and a second solution containing aluminum sulfate, concentrated sulfuric acid, and water were prepared. The zeolite catalyst used as the core was comparative catalyst CAT B, having a silica-to-alumina molar ratio of approximately 143. On the other hand, the ferrielite zeolite shell was prepared with a silica-to-alumina molar ratio of approximately 60.

[0104] <Comparative catalyst CAT E> Comparative catalyst CAT E is a catalyst having a core-shell structure, where the shell is a ZSM-5 zeolite with hierarchical pores, and the core-shell structure has a shell-to-core weight ratio of approximately 1. Comparative catalyst CAT E could be prepared using the preparation process for catalysts having the aforementioned core-shell structure. Tetrapropylammonium hydroxide (TPAOH) was used as a zeolite structure-controlling agent, and cetyltrimethylammonium bromide (CTAB) was used as a hierarchical pore-generating agent. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing aluminum hydroxide, tetrapropylammonium hydroxide, sodium hydroxide, cetyltrimethylammonium bromide, and water were prepared. The zeolite catalyst used as the core was comparative catalyst CAT A, having a silica-to-alumina molar ratio of approximately 61. On the other hand, the ZSM-5 zeolite shell with hierarchical pores was prepared with a silica-to-alumina molar ratio of approximately 160.

[0105] <Comparative catalyst CAT F> Comparative catalyst CAT F is a catalyst having a core-shell structure, where the shell is a conventional silicalite with an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 1. Comparative catalyst CAT F could be prepared using the preparation process for catalysts having the aforementioned core-shell structure. Tetrapropylammonium hydroxide (TPAOH) was used as a structure-controlling agent for the zeolite. A first solution containing silica and a tetrapropylammonium hydroxide solution, and a second solution containing sodium hydroxide were prepared. The zeolite catalyst used as the core was comparative catalyst CAT A, which had a silica-to-alumina molar ratio of approximately 61.

[0106] <Comparative catalyst CAT G> Comparative catalyst CAT G is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 4. Comparative catalyst CAT G could be prepared using the preparation process for catalysts having the above-described core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-determining agent for the zeolite and nanosheet structure. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was comparative catalyst CAT A, which had a silica-to-alumina molar ratio of approximately 61.

[0107] <Comparative catalyst CAT H> Comparative catalyst CAT H is a catalyst having a core-shell structure, where the shell is a conventional silicalite with an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 1. Comparative catalyst CAT H could be prepared using the preparation process for catalysts having the aforementioned core-shell structure. Tetrapropylammonium hydroxide (TPAOH) was used as a structure-controlling agent for the zeolite. A first solution containing silica and a tetrapropylammonium hydroxide solution, and a second solution containing sodium hydroxide were prepared. The zeolite catalyst used as the core was comparative catalyst CAT B, which had a silica-to-alumina molar ratio of approximately 143.

[0108] <Comparative catalyst CAT I> Comparative catalyst CAT I is a catalyst having a core-shell structure, where the shell is conventional silicolite with an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure had a shell-to-core weight ratio of approximately 1. Furthermore, the catalyst further contained manganese in an amount of approximately 5% by weight compared to the weight of the zeolite core. Comparative catalyst CAT I could be prepared using the preparation process for the catalyst having the core-shell structure described above. Tetrapropylammonium hydroxide (TPAOH) was used as a structure-controlling agent for the zeolite. A first solution containing silica and a tetrapropylammonium hydroxide solution, and a second solution containing sodium hydroxide were prepared. The zeolite catalyst used as the core was a catalyst prepared from the preparation process for the manganese (Mn)-containing ferrielite zeolite catalyst described above. The manganese-containing ferrielite zeolite catalyst had a silica-to-alumina molar ratio of approximately 72.

[0109] <Catalyst CAT 1 according to the present invention> Catalyst CAT 1 according to the present invention is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 1. Catalyst CAT 1 according to the present invention could be prepared using the above-described process for preparing catalysts having a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-controlling agent for the zeolite and nanosheet structure. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was comparative catalyst CAT A, which had a silica-to-alumina molar ratio of approximately 61.

[0110] <Catalyst CAT 2 according to the present invention> Catalyst CAT 2 according to the present invention is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 2. Catalyst CAT 2 according to the present invention could be prepared using the preparation process for catalysts having the above-described core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-determining agent for the zeolite and nanosheet structure. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was comparative catalyst CAT A, which had a silica-to-alumina molar ratio of approximately 61.

[0111] <Catalyst CAT 3 according to the present invention> The catalyst CAT 3 according to the present invention is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 2. The catalyst CAT 3 according to the present invention could be prepared using the preparation process for catalysts having the above-described core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-determining agent for the zeolite and nanosheet structure. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was a ZSM-5 zeolite catalyst prepared from the above-described preparation process for ZSM-5 zeolite catalysts. The ZSM-5 zeolite catalyst had a silica-to-alumina molar ratio of approximately 10⁴.

[0112] <Catalyst CAT 4 according to the present invention> The catalyst CAT 4 according to the present invention is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 1. The catalyst CAT 4 according to the present invention could be prepared using the preparation process for catalysts having the above-described core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-determining agent for the zeolite and nanosheet structure. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was comparative catalyst CAT B, which had a silica-to-alumina molar ratio of approximately 143.

[0113] <Catalyst CAT 5 according to the present invention> Catalyst CAT 5 according to the present invention is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 2. Catalyst CAT 5 according to the present invention could be prepared using the above-described process for preparing catalysts having a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structural modifier for the zeolite and nanosheet structure. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was comparative catalyst CAT B, which had a silica-to-alumina molar ratio of approximately 143.

[0114] <Catalyst CAT 6 according to the present invention> The catalyst CAT 6 according to the present invention is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure had a weight ratio of approximately 1 shell to core. Furthermore, the catalyst further contained manganese in an amount of approximately 5% by weight compared to the weight of the zeolite core. The catalyst CAT 6 according to the present invention could be prepared using the preparation process for catalysts having the above-described core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structural modifier for the zeolite and nanosheet structure. A first solution containing tetraethyl orthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was a catalyst prepared from the preparation process for the manganese (Mn)-containing ferrielite zeolite catalyst described above. The aforementioned manganese-containing ferrielite zeolite catalyst had a silica-to-alumina molar ratio of approximately 72.

[0115] <Catalyst CAT 7 according to the present invention> The catalyst CAT 7 according to the present invention is a catalyst having a core-shell structure, where the shell is silicalite having hierarchical pores arranged in a nanosheet-like manner and having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure has a shell-to-core weight ratio of approximately 1. Furthermore, the catalyst further contained manganese in an amount of approximately 5% by weight compared to the weight of the zeolite core. The catalyst CAT 7 according to the present invention could be prepared by impregnating the catalyst CAT 1 according to the present invention with magnesium sulfate and then calcining it at a temperature of approximately 500°C to approximately 600°C.

[0116] [Test to produce light olefins by catalytic cracking of hydrocarbons containing 4 to 7 carbon atoms] It was possible to conduct a test to produce light olefins by catalytic cracking hydrocarbons having 4 to 7 carbon atoms using the following conditions.

[0117] Catalytic cracking was carried out in a fixed-bed reactor using approximately 0.3 g of catalyst. Before the reaction, the catalyst was contacted with hydrogen gas at a flow rate of approximately 50 mL / min for approximately 3 hours. Then, a hydrocarbon with 4 carbon atoms, i.e., 99% isobutane, was supplied at a flow rate of approximately 10 mL / min along with nitrogen gas at a flow rate of 20 mL / min. The reaction was carried out at a temperature of approximately 600°C to approximately 650°C, atmospheric pressure, and a space velocity of approximately 5 watts per hour (WHSV).

[0118] Next, the reaction was monitored by measuring the conversion rate of the reactants and the formation of the resulting compositions at various reaction times after passing through the catalyst, using gas chromatography connected to the outlet of the fixed-bed reactor. The detector used was a flame ionization detector (FID), and the columns used were HP Innowax capillary columns and HP-Plot Al2O3 capillary columns for the separation of the substances and analysis of their respective compositions.

[0119] Figure 1, which shows the characteristics of the crystal structure tested using SEI mode with an accelerating voltage of 20kV using scanning electron microscopy (SEM) technology, reveals that comparative catalyst CAT A, used as the core in the catalyst according to the present invention, has a flower-like particle arrangement and porosity different from commercially available ferrielite zeolites, while comparative catalyst CAT B, also used as the core in the catalyst according to the present invention, has hierarchical pores and clearly organized porosity different from conventional ZSM-5 zeolites. Considering the catalyst according to the present invention which has a core-shell structure, it was found that the surface of the catalyst according to the present invention has hierarchical pores and more beautifully organized porosity than the comparative catalyst.

[0120] From the specific surface area tests of micropores, mesopores, and macropores shown in Table 1, it was found that the catalyst according to the present invention has a ratio of mesopore and macropore volume to total pore volume in the range of 0.35 to 0.90. Compared with a conventional comparative catalyst having a core-shell structure with silicalite as the shell, the catalyst according to the present invention, which has a core-shell structure with silicalite having hierarchical pores arranged in a nanosheet-like manner as the shell, was found to have a larger ratio of mesopore and macropore volume to total pore volume than the conventional comparative catalyst having a core-shell structure with silicalite as the shell.

[0121] Considering the pore size distribution analyzed by Barrett-Joiner-Harenda adsorption (BJH adsorption), the results of the pore size distribution are as shown in Figure 2 and Table 2. The catalyst according to the present invention had a distinctly different distribution of mesopores and macropores compared to the comparative catalyst. The catalyst according to the present invention had a pore size distribution mainly consisting of mesopores with pore sizes in the range of 2 nm to 5 nm, and further containing mesopores with pore sizes in the range of 5 nm to 8 nm and 8 nm to 18 nm. The catalyst according to the present invention showed a larger ratio of the volume of mesopores with each pore size range to the total pore volume compared to the comparative catalyst.

[0122] To study the effect of a catalyst structure having a core-shell structure, comprising a zeolite core selected from ferrielite, ZSM-5, or a mixture thereof, and a silicalite shell having an MFI structure, on the efficiency of producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, the catalyst according to the present invention was studied and compared with a comparative catalyst. The results are shown in Figures 3 to 6.

[0123] Figure 3 shows the conversion rates of various catalysts for the catalytic cracking of butane and their selectivity for each product. The catalyst according to the present invention showed better efficiency than the comparative samples and was found to provide both high selectivity for light olefins and a high conversion rate of the reactants.

[0124] Figure 4 shows the conversion rate of reactants and selectivity for each product of a catalyst having a core-shell structure with a ferrielite zeolite core, compared to a comparative sample catalyst, in the catalytic cracking of butane. The catalyst according to the present invention showed better efficiency than the comparative sample and was found to result in increased selectivity for light olefins. Furthermore, the weight ratio of the shell to the core was a factor influencing the conversion rate of reactants. It was possible to increase the conversion rate of reactants without reducing the selectivity for light olefins.

[0125] Figure 5 shows the reaction conversion rate and selectivity for each product of a core-shell catalyst with a ZSM-5 zeolite core, compared to a comparative sample catalyst, in the catalytic cracking of butane. The catalyst according to the present invention showed better efficiency than the comparative sample and was found to result in higher selectivity for light olefins. Furthermore, the molar ratio of silica to alumina and the weight ratio of shell to core in ZSM-5 were factors that affected the reaction conversion rate. This helped to increase the reaction conversion rate.

[0126] Figure 6 shows the conversion rates of reactants and selectivity for each product of catalysts with manganese (Mn) addition in various configurations compared with comparative sample catalysts in the catalytic cracking of butane. It was revealed that the catalyst according to the present invention exhibits higher selectivity for light olefins compared to the comparative sample.

[0127] From the experimental results described above, it can be said that the catalyst having a core-shell structure according to the present invention exhibited a high conversion rate of reactants and particularly high selectivity for light olefin products in the case of catalytic cracking of hydrocarbons having 4 to 7 carbon atoms as described in the objectives of the present invention.

[0128] [Table 1]

[0129] [Table 2]

[0130] [Best Embodiment of the Invention] The best or preferred embodiment of the present invention is as described in the detailed description of the invention.

Claims

1. A catalyst for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, wherein the catalyst has a core-shell structure comprising a zeolite core selected from ferrielite, ZSM-5, or a mixture thereof, and a silicalite shell having an MFI structure, and the catalyst has the following properties: a) Shell-to-core weight ratio greater than 0 but less than 4, b) Molar ratio of silica to alumina between 60 and 550 (SiO ２ / Al ２ O ３ ), c) A hierarchical pore comprising micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, wherein the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.35 to 0.90, and the mesopores include pores having a pore size of 2 nm to 5 nm, and the ratio of the volume of pores having a pore size of 2 nm to 5 nm to the total pore volume is in the range of 0.08 to 0.

30. A catalyst having [a certain characteristic].

2. The catalyst according to claim 1, wherein the catalyst comprises micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, and the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.40 to 0.

90.

3. The catalyst according to claim 1, wherein the mesopores include pores having a pore size of 2 nm to 5 nm, and the ratio of the volume of pores having a pore size of 2 nm to 5 nm to the total pore volume is in the range of 0.10 to 0.

20.

4. The catalyst according to any one of claims 1 or 3, wherein the mesopores further include pores having a pore size of 5 nm to 8 nm and pores having a pore size of 8 nm to 18 nm.

5. The catalyst according to claim 1, wherein the zeolite core has hierarchical pores, comprising micropores having a pore size in the range of 0.1 nm to 2 nm, mesopores having a pore size in the range of 2 nm to 50 nm, and macropores having a pore size greater than 50 nm, and the ratio of the volume of mesopores and macropores to the total pore volume is in the range of 0.30 to 0.

90.

6. The catalyst according to any one of claims 1 or 5, wherein the zeolite core has the hierarchical pores and is arranged in a nanosheet-like manner.

7. The catalyst according to claim 1, wherein the silicalite shell has the hierarchical pores and is arranged in a nanosheet-like manner.

8. The catalyst according to claim 1, wherein the zeolite core has a silica-to-alumina molar ratio in the range of 35 to 320.

9. The catalyst according to claim 1, wherein the zeolite core is a ferrielite having a particle arrangement resembling a desert rose shape when analyzed in SEI mode at an accelerating voltage of 20 kV using scanning electron microscopy (SEM) technology.

10. The catalyst according to claim 1, wherein the catalyst has a shell-to-core weight ratio that is greater than 0 but less than or equal to 3.

11. The catalyst according to claim 1, wherein the catalyst has a silica-to-alumina molar ratio in the range of 100 to 400.

12. The catalyst according to claim 1, wherein the catalyst comprises a ZSM-5 core having a silica-to-alumina molar ratio in the range of 120 or more but 300 or less, and the silicalite shell, and the catalyst has a shell-to-core weight ratio greater than 0 but 1.5 or less.

13. The catalyst according to claim 1, wherein the catalyst comprises a ZSM-5 core having a silica-to-alumina molar ratio in the range of 50 or more but 120 or less, and the silicalite shell, and the catalyst has a shell-to-core weight ratio greater than 0 but 3 or less.

14. The catalyst according to claim 1, wherein the catalyst comprises a ferrielite core having a silica-to-alumina molar ratio in the range of 150 or more but 300 or less, and a silicalite shell, and the catalyst has a shell-to-core weight ratio greater than 0 but 2 or less.

15. The catalyst according to claim 1, wherein the catalyst comprises a ferrielite core having a silica-to-alumina molar ratio in the range of 50 or more but 150 or less, and the silicalite shell, and the catalyst has a shell-to-core weight ratio greater than 0 but 2 or less.

16. The catalyst according to claim 1, wherein the catalyst further comprises manganese (Mn).

17. The catalyst according to claim 16, wherein the catalyst further comprises manganese (Mn) in an amount of 1% to 15% by weight compared to the weight of the zeolite core.

18. The catalyst according to claim 17, wherein the catalyst further comprises manganese (Mn) in an amount of 5% to 10% by weight compared to the weight of the zeolite core.

19. The catalyst according to claim 1, wherein the zeolite core further comprises manganese (Mn).

20. The catalyst according to claim 19, wherein the zeolite core further contains manganese (Mn) in an amount of 1% to 15% by weight relative to the weight of the zeolite core.

21. The catalyst according to claim 20, wherein the zeolite core further contains manganese (Mn) in an amount of 5% to 10% by weight relative to the weight of the zeolite core.

22. The catalyst according to claim 1, wherein the hydrocarbon is selected from butane, pentane, hexane, or heptane.

23. The catalyst according to claim 22, wherein the hydrocarbon is butane.

24. The catalyst according to claim 1, wherein the light olefin is ethylene and propylene.

25. A method for producing a light olefin from catalytic cracking of a hydrocarbon having 4 to 7 carbon atoms, comprising contacting the hydrocarbon having 4 to 7 carbon atoms with the catalyst described in claim 1 at a temperature in the range of 400°C to 700°C and a pressure in the range of 0.1 bar to 10 bar.

26. A method for producing a light olefin according to claim 25, wherein the contact between the hydrocarbon having 4 to 7 carbon atoms and the catalyst is carried out at a temperature in the range of 500°C to 700°C.

27. The method for producing a light olefin according to claim 25, wherein the hydrocarbon is selected from butane, pentane, hexane, or heptane.

28. A method for producing a light olefin according to claim 27, wherein the hydrocarbon is butane.

29. A method for producing a light olefin according to claim 25, wherein the light olefin is ethylene and propylene.

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