Catalyst for producing light olefins and method for producing light olefins by 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 in particular 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 by using the catalyst. [Background technology]

[0002] Light olefins, such as ethylene and propylene, are important reactants in the production of polymers, particularly polyethylene and polypropylene. Light olefins are generally industrially produced by thermal steam cracking from naphtha or ethane separated from natural gas. However, the production of light olefins by this method requires high heat at temperatures of 800°C to 900°C, which is known to be disadvantageous in terms of energy consumption. Furthermore, there is also the problem of coking, where a large amount of heavy hydrocarbons having more than nine carbon atoms accumulates in the system. This leads to frequent shutdowns of the production process for reactor maintenance. Therefore, there is an alternative method for producing light olefins from catalytic cracking of naphtha. This method has the advantages of being able to produce a large number of light olefins using lower reaction temperatures, as well as reducing energy consumption in production and alleviating the coking problem in the system.

[0003] Zeolites are crystalline aluminosilicate compounds with excellent properties, such as adjustable acidity-basicity, thermal and chemical stability, and shape selectivity depending on the reaction used. Therefore, zeolites have been applied to various processes, such as adsorbents, ion exchangers, and heterogeneous catalysts, which can function as catalysts or supports. The production of light olefins from catalytic cracking using zeolites as catalysts is interesting and popular because zeolites contain suitable catalytic acid sites and have porosity with specific properties related to the selectivity of desired products.

[0004] The following documents disclose or report on the production of light olefins from catalytic cracking of naphtha using zeolites as catalysts:

[0005] Patent documents 1, 2, and 3 disclose aluminosilicate or zeolite catalysts for the production of olefins from catalytic cracking of hydrocarbons, including naphtha, by adding potassium, sodium, gallium, and organic ammonium cation compounds. This included the development of catalysts that are mixtures of different types of zeolites between small pore zeolites such as chabazite, erionite, ferrierite, and ZSM-22, and medium pore zeolites, which are nanosilicalites with silica to alumina ratios of over 200, preferably in the range of 600 to 1600.

[0006] Patent documents 4 and 5 disclose catalysts for a process for producing olefins from catalytic cracking of hydrocarbons, including naphtha and hydrocarbons having 4 to 7 carbon atoms, using a catalyst containing various zeolites with a silica-to-alumina ratio of more than 300, such as ZSM-5, ZSM-11, or mixtures thereof, and the addition of phosphorus. This also included the development of a catalyst that is a mixture of different types of zeolites, between a first zeolite having a medium pore size, a second zeolite having a structure different 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 said catalyst, in which the core was nano-ZSM-5 and the shell was silicalite-1 prepared from the use of tetrapropylammonium hydroxide (TPAOH) as a structure-directing agent for the zeolite.

[0008] The patent document 7 discloses a zeolite-bound zeolite catalyst composition comprising a first zeolite and a binder comprising a second zeolite having a structure different from that of the first zeolite. The second zeolite may be partially coated on 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 greater than 7 Å.

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

[0010] The '10 patent discloses a zeolite-bound zeolite catalyst composition comprising a first zeolite and a binder comprising a second zeolite having an average particle size smaller than the first zeolite. Either zeolite 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] The patent document 11 discloses a zeolite catalyst composition comprising a first zeolite and a layer of a second zeolite having an average particle size smaller than that of the first zeolite, covering at least a portion of the surface of the first zeolite. Either zeolite 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 greater than 7 Å.

[0012] Patent document 12 discloses a zeolite-bound zeolite catalyst composition comprising a first zeolite, a binder comprising a second zeolite having a structure different from that of the first zeolite, and a non-zeolite binder in an amount of less than 10%. Either zeolite 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 greater than 7 Å.

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

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

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

[0016] [Patent Document 1] U.S. Patent No. 7,981,273 [Patent Document 2] U.S. Patent No. 8,157,985 [Patent Document 3] US Patent Application Publication No. 2010 / 0105974 [Patent Document 4] U.S. Patent No. 6,222,087 [Patent Document 5] U.S. Patent No. 326,332 [Patent Document 6] Chinese Patent Application Publication No. 107670687 [Patent Document 7] International Publication No. 1997 / 045198 [Patent Document 8] Chinese Patent Application Publication No. 113751057 [Patent Document 9] Chinese Patent Application Publication No. 113908879 [Patent Document 10] WO 1996 / 016004 [Patent Document 11] US Patent Application Publication No. 2006 / 0011514 [Patent Document 12] Malaysian Patent No. 120519 [Patent Document 13] U.S. Patent No. 6,858,129 [Patent Document 14] US Patent Application Publication No. 2018 / 0193826 [Patent Document 15] U.S. Patent No. 10,159,967 Summary of the Invention [Problem to be solved by the invention]

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

[0018] For the above reasons, 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 process for producing light olefins and provides high conversion of reactants, particularly high selectivity to light olefins, and a process for producing light olefins by using the catalyst. [Means for solving the problem]

[0019] The present invention provides 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 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) 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, 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 comprise pores having a pore size of 2 nm to 5 nm, wherein the ratio of the volume of the 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 object of the present invention is to prepare a catalyst having the following formula:

[0020] In another embodiment, the present invention provides a method for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, comprising contacting the hydrocarbons 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 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) 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, 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 comprise pores having a pore size of 2 nm to 5 nm, wherein the ratio of the volume of the 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 present invention relates to a method comprising: [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 shows the characteristics of the crystalline structure examined by scanning electron microscopy (SEM) techniques. [Figure 2] FIG. 1 shows the pore size distribution analyzed by Barrett-Joyner-Halenda adsorption (BJH adsorption). [Figure 3] FIG. 1 shows the reactant conversion and selectivity to each product for various catalysts in the catalytic cracking of isobutane. [Figure 4] FIG. 1 shows the reactant conversion and selectivity to each product of a catalyst having a core-shell structure in which the zeolite core is ferrierite, compared with a comparative sample catalyst, in the catalytic cracking of isobutane. [Figure 5] FIG. 1 shows the reactant conversion and selectivity to each product of a catalyst having a core-shell structure in which the zeolite core is ZSM-5, compared with a comparative sample catalyst, in the catalytic cracking of isobutane. [Figure 6] FIG. 1 shows the conversion of reactants and selectivity to each product in various modes of a catalyst with added manganese compared to a comparative sample catalyst in catalytic cracking of isobutane. DETAILED DESCRIPTION OF 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 process for producing light olefins and provides high conversion of reactants, particularly high selectivity for light olefins, and a process for producing light olefins by using the catalyst, which are described in the following embodiments of the present invention.

[0023] Any embodiment described herein is meant to include applications to other embodiments of the invention unless otherwise specified.

[0024] Unless otherwise specified, technical or scientific terms used herein have definitions that are understood by one of ordinary skill in the art.

[0025] Any tools, equipment, methods, or chemicals referred to herein refer to tools, equipment, methods, or chemicals that are commonly operated or used by those skilled in the art, unless otherwise specified as tools, equipment, methods, or chemicals that are unique only to this invention.

[0026] The use of the singular noun or 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, even if not specifically set forth in the claims, that can be achieved by those skilled in the art without any experimentation, through the manipulation, performance, modification, or adjustment of any factor that achieves a purpose that is substantially different from the present invention and has utility, and results in the same results as the present embodiments. Accordingly, all alternative or similar purposes to the present embodiments, including all minor modifications or adjustments that may be apparent to those skilled in the art, should be construed as remaining within the spirit, scope, and concept of the invention as found in the appended claims.

[0028] Throughout this application, the term "about" refers to any numerical value found or expressed herein that may vary or deviate due to some error of the equipment, method, or individual using said equipment or method, including variations or deviations resulting from changes in reaction conditions of uncontrollable factors such as humidity and temperature. Zeolite in this invention refers to 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] Silicalite in the present invention means a zeolite compound having a polycrystalline structure with an infinite silica to alumina ratio (SiO2 / Al2O3=∞).

[0030] Hereinafter, embodiments of the present invention will be described, but they are not intended to limit the scope of the present invention in any way.

[0031] The present invention provides 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 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) 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, 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 comprise pores having a pore size of 2 nm to 5 nm, wherein the ratio of the volume of the 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 present invention relates to a catalyst having the formula:

[0032] In one embodiment of the present invention, the catalyst has hierarchical pores 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, and the ratio of the volume of the mesopores and macropores to the total pore volume is in the range of 0.40 to 0.90, preferably 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, 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.

[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, and 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, and 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 hierarchical pores 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 hierarchical pores 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, and the ratio of the volume of the 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 shape.

[0040] In one embodiment of the present invention, the silicalite shell has hierarchical pores 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.

[0041] In one embodiment of the present invention, the silicalite shell has hierarchical pores arranged in a nanosheet shape.

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

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

[0044] In one embodiment of the present invention, the zeolite core is ferrierite having a flower-like particle arrangement when analyzed by scanning electron microscope (SEM) technique in SEI mode at an accelerating voltage of 20 kV.

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

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

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

[0048] In one embodiment of the present invention, the catalyst is about 50 m 2 / g~about 300m 2 / g, preferably about 70m 2 / g ~ approx. 250m 2 / g, most preferably about 80m 2 / g~about 200m 2 / g ext )

[0049] In one embodiment of the invention, 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 a silicalite shell, and the catalyst has a shell to core weight ratio of greater than 0 but 1.5 or less.

[0050] In one embodiment of the invention, 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 a silicalite shell, and the catalyst has a shell to core weight ratio of greater than 0 but 3 or less.

[0051] In one embodiment of the invention, the catalyst comprises a ferrierite 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 of greater than 0 but 2 or less.

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

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

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

[0056] In one embodiment of the 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 invention, the light olefins are ethylene and propylene.

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

[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 comprises the following steps: a) preparing a mixture comprising a first zeolite-preparing compound and a first soft structure directing agent, and subjecting the mixture to a hydrothermal process at a specified temperature and time to convert the mixture into a zeolite; b) preparing a mixture comprising a compound for preparing silicalite, a second soft structure directing 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 with a core-shell structure; may include:

[0060] In one embodiment of the present invention, each step of the method for preparing the catalyst may further comprise 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 comprise a drying step.

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

[0063] In one embodiment of the present invention, each step of the method for preparing the catalyst described above may further comprise 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 not limited to, ammonium nitrate (NH4NO3) or ammonium hydroxide.

[0065] In one embodiment of the present invention, the compound from which the first zeolite is prepared 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-directing 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 tetraalkylammonium salts selected from, but not limited to, tetrapropylammonium hydroxide, tetrapropylammonium bromide, or tetrabutylammonium hydroxide.

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

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

[0070] In one embodiment of the invention, the second, soft structure directing 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 invention, the quaternary phosphonium salt is selected from tetrabutylphosphonium hydroxide (TBPOH) or tributylhexadecylphosphonium bromide.

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

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

[0074] In another aspect, the present invention relates to a process for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, comprising contacting the hydrocarbons 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 as described above or a catalyst obtained from the process for preparing the catalyst as described above.

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

[0076] In one embodiment of the present invention, the contacting of the hydrocarbon having 4 to 7 carbon atoms with the catalyst is carried out at a pressure ranging from about 1 bar to about 10 bar, preferably from 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 catalytic cracking of hydrocarbons having 4 to 7 carbon atoms are light olefins, preferably ethylene and propylene.

[0078] In one aspect of the present invention, the process for producing light olefins from catalytic cracking can be carried out in a reactor that is not limited to a fixed bed reactor, which can be carried out in a batch or continuous mode, or can be carried out in a fixed bed system, a moving bed system, a fluidized bed system, or a batch system.

[0079] The weight hourly space velocity (WHSV) of the hydrocarbon feed 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] In general, one skilled in the art can adjust the conditions for catalytic cracking 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 examples are merely illustrative of one embodiment of the present invention and are not intended to limit the scope of the invention in any way.

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

[0083] <Preparation of Ferrierite (FER) Zeolite Catalyst> A preparation of ferrierite zeolite catalyst could be prepared as follows using pyrrolidine as a structure directing agent for the zeolite by a hydrothermal method.

[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 with continuous stirring. The resulting mixture was then subjected to a hydrothermal process at a temperature of about 130°C to about 180°C to convert the mixture into zeolite.

[0085] The obtained zeolite was then washed with deionized water, dried, and calcined at a temperature of about 500°C to about 650°C to obtain a white powder of zeolite.

[0086] Thereafter, the obtained zeolite was subjected to ion exchange by contacting it with a 1M ammonium nitrate (NH4NO3) solution while continuously stirring at a temperature of about 60°C to about 90°C. 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 preparation of the ZSM-5 zeolite catalyst could be carried out 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] Thereafter, the obtained zeolite was subjected to ion exchange by contacting it with a 1M ammonium nitrate (NH4NO3) solution while continuously stirring at a temperature of about 60°C to about 90°C. 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 silicalite catalyst preparation with infinite silica-to-alumina ratio (SiO2 / Al2O3 = ∞) could be prepared by a hydrothermal method using tetrabutylphosphonium hydroxide (TBPOH) as a structure-directing agent for the zeolite 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 with continuous stirring. The resulting mixture was then subjected to a hydrothermal process at a temperature of about 100°C to about 200°C to convert the mixture into zeolite.

[0093] The obtained zeolite was then washed with deionized water, dried, and calcined at a temperature of about 500°C to about 650°C to obtain a white powder of zeolite.

[0094] The resulting zeolite was then 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 with continuous stirring. The zeolite was then washed with deionized water, dried, and calcined at a temperature of about 500°C to about 600°C to obtain a silicalite catalyst with hierarchical pores arranged in a nanosheet shape.

[0095] <Preparation of manganese (Mn)-containing ferrierite zeolite catalyst> A preparation of manganese (Mn)-containing ferrierite zeolite catalyst could be prepared using the above-described process for preparing ferrierite zeolite catalyst by hydrothermal method and adding manganese sulfate to the mixture before subjecting the mixture to the hydrothermal process.

[0096] <Preparation of catalysts with core-shell structure> The preparation of catalysts with core-shell structure could be prepared by hydrothermal method as follows.

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

[0098] The obtained zeolite was then washed with deionized water, dried, and calcined at a temperature of about 500°C to about 650°C to obtain a white powder of zeolite.

[0099] The resulting zeolite was then 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 with continuous stirring, followed by washing with deionized water, drying, and calcining at a temperature of about 500°C to about 600°C to obtain a catalyst having a core-shell structure.

[0100] [Preparation of Comparative Catalysts and Catalysts According to the Invention] <Comparative catalyst CAT A> A comparative catalyst, CAT A, was prepared using the process for preparing a ferrierite zeolite catalyst described above, and had a silica to alumina molar ratio of about 61.

[0101] <Comparative catalyst CAT B> A comparative catalyst, CAT B, was prepared using the process for preparing ZSM-5 zeolite catalyst described above, and had a silica to alumina molar ratio of about 143.

[0102] <Comparative catalyst CAT C> A comparative catalyst, CAT C, could be prepared using the process for preparing the silicalite catalyst described above.

[0103] <Comparative catalyst CAT D> Comparative catalyst CAT D was a catalyst having a core-shell structure, where the shell was ferrierite zeolite, and the core-shell structure had a shell-to-core weight ratio of about 1. Comparative catalyst CAT D could be prepared using the above-described process for preparing a catalyst having a core-shell structure. Pyrrolidine was used as a zeolite structure-directing agent. 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, which had a silica-to-alumina molar ratio of about 143. Meanwhile, the ferrierite zeolite shell was prepared with a silica-to-alumina molar ratio of about 60.

[0104] <Comparative catalyst CAT E> Comparative catalyst CAT E was a catalyst having a core-shell structure, where the shell was a ZSM-5 zeolite with hierarchical pores, and the core-shell structure had a shell-to-core weight ratio of about 1. Comparative catalyst CAT E could be prepared using the above-described process for preparing a catalyst with a core-shell structure. Tetrapropylammonium hydroxide (TPAOH) was used as the zeolite structure-directing agent, and cetyltrimethylammonium bromide (CTAB) was used as the 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, which had a silica-to-alumina molar ratio of about 61. Meanwhile, the ZSM-5 zeolite shell with hierarchical pores was prepared with a silica-to-alumina molar ratio of about 160.

[0105] <Comparative catalyst CAT F> Comparative catalyst CAT F was a catalyst having a core-shell structure, where the shell was a conventional silicalite having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure had a shell-to-core weight ratio of about 1. Comparative catalyst CAT F could be prepared using the above-described process for preparing a catalyst having a core-shell structure. Tetrapropylammonium hydroxide (TPAOH) was used as a zeolite structure-directing agent. 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 about 61.

[0106] <Comparative catalyst CAT G> The comparative catalyst CAT G was a catalyst with a core-shell structure, in which the shell was a silicalite with hierarchical pores arranged in a nanosheet pattern and an infinite silica-to-alumina ratio (SiO2 / Al2O3 = ∞), and the core-shell structure had a shell-to-core weight ratio of approximately 4. The comparative catalyst CAT G was prepared using the above-described process for preparing a catalyst with a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-directing 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 the comparative catalyst CAT A, with a silica-to-alumina molar ratio of approximately 61.

[0107] <Comparative catalyst CAT H> The comparative catalyst CAT H was a catalyst having a core-shell structure, where the shell was a conventional silicalite having an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure had a shell-to-core weight ratio of about 1. The comparative catalyst CAT H could be prepared using the above-described process for preparing a catalyst having a core-shell structure. Tetrapropylammonium hydroxide (TPAOH) was used as a zeolite structure-directing agent. 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 the comparative catalyst CAT B, which had a silica-to-alumina molar ratio of about 143.

[0108] <Comparative catalyst CAT I> Comparative catalyst CAT I was a catalyst having a core-shell structure, where the shell was a conventional silicalite with an infinite silica-to-alumina ratio (SiO2 / Al2O3 = ∞), and the core-shell structure had a shell-to-core weight ratio of about 1. Furthermore, the catalyst further contained manganese in an amount of about 5 wt% relative to the weight of the zeolite core. Comparative catalyst CAT I was prepared using the above-described process for preparing a catalyst having a core-shell structure. Tetrapropylammonium hydroxide (TPAOH) was used as a zeolite structure-directing agent. 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 the catalyst prepared by the above-described process for preparing a manganese (Mn)-containing ferrierite zeolite catalyst. The manganese-containing ferrierite zeolite catalyst had a silica-to-alumina molar ratio of about 72.

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

[0110] <Catalyst CAT 2 according to the present invention> The catalyst CAT 2 according to the present invention is a catalyst having a core-shell structure, where the shell is a silicalite having hierarchical pores arranged in a nanosheet shape and an infinite silica-to-alumina ratio (SiO2 / Al2O3 = ∞), and the core-shell structure has a shell-to-core weight ratio of about 2. The catalyst CAT 2 according to the present invention can be prepared using the above-described process for preparing a catalyst having a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-directing agent for the zeolite and nanosheet structure. A first solution containing tetraethylorthosilicate (TEOS) and a second solution containing tetrabutylphosphonium hydroxide, sodium hydroxide, and water were prepared. The zeolite catalyst used as the core was the comparative catalyst CAT A, which had a silica-to-alumina molar ratio of about 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, in which the shell is a silicalite having hierarchical pores arranged in a nanosheet pattern and 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 above-described process for preparing a catalyst having a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-directing 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 according to the above-described process for preparing a ZSM-5 zeolite catalyst. 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, in which the shell is a silicalite having hierarchical pores arranged in a nanosheet pattern and an infinite silica-to-alumina ratio (SiO2 / Al2O3 = ∞), and the core-shell structure has a shell-to-core weight ratio of about 1. The catalyst CAT 4 according to the present invention could be prepared using the above-described process for preparing a catalyst having a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-directing 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 the comparative catalyst CAT B, which had a silica-to-alumina molar ratio of about 143.

[0113] <Catalyst CAT 5 according to the present invention> The catalyst CAT 5 according to the present invention is a catalyst having a core-shell structure, in which the shell is a silicalite having hierarchical pores arranged in a nanosheet shape and an infinite silica-to-alumina ratio (SiO2 / Al2O3 = ∞), and the core-shell structure has a shell-to-core weight ratio of about 2. The catalyst CAT 5 according to the present invention could be prepared using the above-described process for preparing a catalyst having a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-directing 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 the comparative catalyst CAT B, which had a silica-to-alumina molar ratio of about 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 a silicalite having hierarchical pores arranged in a nanosheet pattern and an infinite silica-to-alumina ratio (SiO2 / Al2O3 = ∞), and the core-shell structure has a shell-to-core weight ratio of about 1. Furthermore, the catalyst further contains manganese in an amount of about 5 wt% relative to the weight of the zeolite core. The catalyst CAT 6 according to the present invention could be prepared using the above-described process for preparing a catalyst having a core-shell structure. Tetrabutylphosphonium hydroxide (TBPOH) was used as a structure-directing 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 the catalyst prepared by the above-described process for preparing a manganese (Mn)-containing ferrierite zeolite catalyst. The manganese-containing ferrierite zeolite catalyst had a silica to alumina molar ratio of about 72.

[0115] <Catalyst CAT 7 according to the present invention> The catalyst CAT 7 according to the present invention was a catalyst having a core-shell structure, in which the shell was silicalite having hierarchical pores arranged in a nanosheet shape and an infinite silica-to-alumina ratio (SiO2 / Al2O3=∞), and the core-shell structure had a shell-to-core weight ratio of about 1. Furthermore, the catalyst further contained manganese in an amount of about 5 wt % 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, followed by calcining at a temperature of about 500°C to about 600°C.

[0116] [Test to produce light olefins by catalytic cracking of hydrocarbons with 4 to 7 carbon atoms] Tests for catalytic cracking of hydrocarbons having 4 to 7 carbon atoms to produce light olefins could be carried out using the following conditions:

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

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

[0119] 1, which shows the characteristics of the crystal structure examined by scanning electron microscope (SEM) technique using SEI mode at an accelerating voltage of 20 kV, reveals that the comparative catalyst CAT A used as the core in the catalyst of the present invention had a flower-like particle arrangement and porosity different from that of commercially available ferrierite zeolite, while the comparative catalyst CAT B used as the core in the catalyst of the present invention had hierarchical pores and clearly organized porosity different from that of conventional ZSM-5 zeolite. Considering the catalyst of the present invention having a core-shell structure, it was found that the surface of the catalyst of the present invention had hierarchical pores and a more beautifully organized porosity than the comparative catalyst.

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

[0121] Considering the pore size distribution analyzed by Barrett-Joyner-Halenda adsorption (BJH adsorption), the pore size distribution results were as shown in Figure 2 and Table 2. The catalyst of the present invention had a distribution of mesopores and macropores that was clearly different from that of the comparative catalyst. The catalyst of the present invention had a pore size distribution of mesopores mainly having pore sizes in the range of 2 nm to 5 nm, and further contained mesopores having pore sizes in the range of 5 nm to 8 nm and 8 nm to 18 nm. The catalyst of the present invention showed a larger ratio of the volume of mesopores having pore sizes in each range to the total pore volume than the comparative catalyst.

[0122] To study the effect of the structure of a catalyst having a core-shell structure, which comprises a zeolite core selected from ferrierite, 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 of the present invention was studied and compared with a comparative catalyst. The results are shown in Figures 3 to 6.

[0123] 3 shows the conversion of reactants and selectivity to each product of various catalysts in catalytic cracking of butane. It was found that the catalyst according to the present invention showed better efficiency than the comparative sample, resulting in both high selectivity to light olefins and high conversion of reactants.

[0124] Figure 4 shows the reactant conversion and selectivity to each product of a catalyst having a core-shell structure in which the zeolite core is ferrierite, compared to a comparative catalyst in the catalytic cracking of butane. It was found that the catalyst of the present invention exhibited better efficiency than the comparative catalyst, resulting in increased selectivity to light olefins. Furthermore, the shell-to-core weight ratio was a factor affecting the reactant conversion. It could help increase the reactant conversion without reducing the selectivity to light olefins.

[0125] Figure 5 shows the reactant conversion and selectivity to each product of a catalyst having a core-shell structure in which the zeolite core is ZSM-5, compared with a comparative sample catalyst, in catalytic cracking of butane. It was found that the catalyst of the present invention exhibited better efficiency than the comparative sample and provided higher selectivity to light olefins. Furthermore, the silica-to-alumina molar ratio and shell-to-core weight ratio of ZSM-5 were factors that affected the reactant conversion, which could help increase the reactant conversion.

[0126] 6 shows the conversion of reactants and the selectivity to each product in various modes of catalysts with added manganese (Mn) compared to the comparative sample catalyst in catalytic cracking of butane. It was revealed that the catalyst of the present invention has an increased selectivity to light olefins compared to the comparative sample.

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

[0128] [Table 1]

[0129] [Table 2]

[0130] [Best embodiment of the present invention] The best mode or preferred embodiment of the present invention is as set forth 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 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 (SiO ２ / Al ２ O ３ ), c) 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, 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 comprise pores having a pore size of 2 nm to 5 nm, wherein the ratio of the volume of the 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

2. 2. The catalyst according to claim 1, wherein the catalyst has hierarchical pores 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, and the ratio of the volume of the mesopores and macropores to the total pore volume is in the range of 0.40 to 0.

90.

3. 2. The catalyst of claim 1, wherein the mesopores comprise pores having a pore size of 2 nm to 5 nm, and wherein 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. 4. The catalyst of claim 1, wherein the mesopores further comprise pores having a pore size of 5 nm to 8 nm and pores having a pore size of 8 nm to 18 nm.

5. 2. The catalyst according to claim 1, wherein the zeolite core has hierarchical pores 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, and the ratio of the volume of the mesopores and macropores to the total pore volume is in the range of 0.30 to 0.

90.

6. The catalyst according to claim 1 or 5, wherein the zeolite core has the hierarchical pores and is arranged in a nanosheet shape.

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

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

9. 2. The catalyst of claim 1, wherein the zeolite core is ferrierite having a flower-like particle arrangement when analyzed by scanning electron microscope (SEM) technique in SEI mode at an accelerating voltage of 20 kV.

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

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

12. 2. The catalyst of 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. 2. The catalyst of 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 of greater than 0 but 3 or less.

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

15. 2. The catalyst of claim 1, wherein the catalyst comprises a ferrierite 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 of greater than 0 but 2 or less.

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

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

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

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

20. 20. The catalyst of claim 19, wherein the zeolite core further comprises manganese (Mn) in an amount of 1 wt% to 15 wt% compared to the weight of the zeolite core.

21. 21. The catalyst of claim 20, wherein the zeolite core further comprises manganese (Mn) in an amount of 5 wt% to 10 wt% compared to the weight of the zeolite core.

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

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

24. 2. The catalyst of claim 1, wherein the light olefins are ethylene and propylene.

25. 1. A process for producing light olefins from catalytic cracking of hydrocarbons having 4 to 7 carbon atoms, comprising contacting the hydrocarbons 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 ferrierite, ZSM-5, or a mixture thereof, and a silicalite shell having an MFI structure, and wherein 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 (SiO ２ / Al ２ O ３ ), c) 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, 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 comprise pores having a pore size of 2 nm to 5 nm, wherein the ratio of the volume of the 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 method comprising:

26. 26. The method for producing light olefins according to claim 25, wherein the catalyst 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 the mesopores and macropores to the total pore volume is in the range of 0.40 to 0.

90.

27. 26. The method for producing light olefins according to claim 25, wherein the mesopores comprise 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.

28. 28. The method for producing light olefins according to claim 25, wherein the mesopores further comprise pores having a pore size of 5 nm to 8 nm and pores having a pore size of 8 nm to 18 nm.

29. 26. The method for producing light olefins according to claim 25, 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 the mesopores and the macropores to the total pore volume is in the range of 0.30 to 0.

90.

30. 30. The method for producing light olefins according to claim 25 or 29, wherein the zeolite core has the hierarchical pores and is arranged in a nanosheet-like manner.

31. 26. The method for producing light olefins according to claim 25, wherein the silicalite shell has the hierarchical pores and is arranged in a nanosheet shape.

32. 26. The process for producing light olefins according to claim 25, wherein the zeolite core has a silica to alumina molar ratio in the range of 35 to 320.

33. 26. The method for producing light olefins according to claim 25, wherein the zeolite core is ferrierite having a flower-like particle arrangement when analyzed by scanning electron microscope (SEM) technique in SEI mode at an accelerating voltage of 20 kV.

34. 26. The process for producing light olefins of claim 25, wherein the catalyst has a shell to core weight ratio greater than 0 but less than or equal to 3.

35. 26. The process for producing light olefins according to claim 25, wherein the catalyst has a silica to alumina molar ratio in the range of 100 to 400.

36. 26. The process for producing light olefins according to claim 25, 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 of greater than 0 but 1.5 or less.

37. 26. The process for producing light olefins according to claim 25, 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 of greater than 0 but 3 or less.

38. 26. The method for producing light olefins according to claim 25, wherein the catalyst comprises a ferrierite core having a molar ratio of silica to alumina in the range of 150 or more but 300 or less, and the silicalite shell, and the catalyst has a shell to core weight ratio of greater than 0 but 2 or less.

39. 26. The method for producing light olefins according to claim 25, wherein the catalyst comprises a ferrierite core having a molar ratio of silica to alumina 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 of greater than 0 but 2 or less.

40. 26. The method for producing light olefins according to claim 25, wherein the catalyst further comprises manganese (Mn).

41. 41. The process for producing light olefins according to claim 40, wherein the catalyst further comprises manganese (Mn) in an amount of 1 wt% to 15 wt% compared to the weight of the zeolite core.

42. 42. The process for producing light olefins according to claim 41, wherein the catalyst further comprises manganese (Mn) in an amount of 5 wt% to 10 wt% compared to the weight of the zeolite core.

43. 26. The method for producing light olefins according to claim 25, wherein the zeolite core further comprises manganese (Mn).

44. 44. The process for producing light olefins according to claim 43, wherein the zeolite core further comprises manganese (Mn) in an amount of 1 wt% to 15 wt% compared to the weight of the zeolite core.

45. 45. The process for producing light olefins according to claim 44, wherein the zeolite core further comprises manganese (Mn) in an amount of 5 wt% to 10 wt% compared to the weight of the zeolite core.

46. 26. The process for producing light olefins according to claim 25, wherein the contacting of the hydrocarbon having 4 to 7 carbon atoms with the catalyst is carried out at a temperature in the range of 500°C to 700°C.

47. 26. The method for producing light olefins according to claim 25, wherein the hydrocarbon is selected from butane, pentane, hexane, or heptane.

48. 48. The method for producing light olefins according to claim 47, wherein the hydrocarbon is butane.

49. 26. The method for producing light olefins according to claim 25, wherein the light olefins are ethylene and propylene.

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