An alkane-to-olefin catalyst, its preparation method and application

Abstract

This invention discloses an alkane-olefin reducing catalyst, its preparation method, and its application. The alkane-olefin reducing catalyst comprises a first molecular sieve, a second molecular sieve, and an optional binder. The first molecular sieve is an EMT molecular sieve, and the second molecular sieve is selected from at least one of 12-membered ring-channel molecular sieves other than EMT molecular sieves. The catalyst further includes a binder. The first molecular sieve is a carbon-containing EMT molecular sieve, wherein the carbon content is 0.02–0.5 wt%, and the Na₂O content is less than 2.5 wt%. This invention uses carbon-containing EMT molecular sieves and BEA molecular sieves as the active components of the catalyst, which has the advantages of large feedstock throughput and long service life.

Description

Technical Field

[0001] This invention relates to an alkane-olefin reducing catalyst, its preparation method and application, and in particular to an isopentane-olefin reducing catalyst, its preparation method and application. Background Technology

[0002] Isopentane is mainly used as a solvent in the production of linear low-density polyethylene and full-density polyethylene, and as a blowing agent in expandable polystyrene and polyurethane foam. With the continuous advancement of polyethylene production technology, the requirements for the solvent isopentane are becoming increasingly stringent. The requirement for the olefin concentration in isopentane in polyethylene plants has been reduced from 500 ppm to 50 ppm; if the requirements are even more stringent, the olefin concentration needs to be reduced from 300 ppm to 30 ppm.

[0003] China requires more than 30,000 tons of isopentane solvent annually. If the quality of isopentane cannot be guaranteed, it will affect the normal production and economic benefits of the plant.

[0004] The isomers of pentene in isopentane feedstock have very similar boiling points to isopentane, making them difficult to separate using conventional distillation processes. Cracked C5 hydrocarbons contain large amounts of dienes and mono-olefins; using these as feedstocks to produce isopentane requires a complex process involving one or two stages of hydrogenation at high operating temperatures and pressures to saturate the olefins before distillation to obtain the isopentane product. This process is unsuitable for isopentane production. Using light hydrocarbons from oil fields as feedstocks often results in isopentane products that fail to meet quality standards, exhibiting excessive unsaturated hydrocarbon or sulfur content. This necessitates adding hydrogenation reaction units to ensure product quality, further complicating the process and increasing production costs.

[0005] CN 107573204 A uses Cu or Ag modified HZSM-5 as a pentane refining agent, under conditions of temperature below 50℃, pressure below 0.5MPa, and space velocity below 1.0h⁻¹. -1 The reaction occurs under these conditions. Therefore, high-space-velocity catalysts need to be redesigned and studied.

[0006] Currently, Y-type molecular sieves are commonly used as catalysts for deolefination. However, due to the small pore diameter of Y-type molecular sieves, the large molecules generated during olefin alkylation cannot escape quickly from their pores, easily leading to pore blockage and deactivation.

[0007] Exxon Mobil developed the Olgone aromatics refining technology, which uses an MCM-22 molecular sieve catalyst instead of clay to remove trace amounts of olefins from reformate without modifying the process. The deactivated catalyst can be reactivated through ex-situ regeneration.

[0008] Exxon Mobil uses MWW molecular sieves and clay as catalysts in CN 101309999A to reduce the bromine index of hydrocarbon feedstocks. CN 101313052A describes the use of such catalysts for the deolefination reaction of benzene feedstocks containing trace amounts of oxygen compounds.

[0009] EMT molecular sieves have a zeolite framework structure with a three-dimensional 12-membered ring cross-channel system. They are highly acidic and have a large acid content, making them excellent catalysts for isomerization, aromatization, and alkylation.

[0010] Currently, there is no literature on the use of EMT molecular sieve catalysts for the olefin reduction reaction of alkanes, especially isopentane. Summary of the Invention

[0011] This invention addresses the problems of low space velocity in previous methods for reducing alkanes (especially isopentane) to olefins and the catalyst reaction. This invention provides a method for reducing alkanes to olefins, wherein the alkanes react with a catalyst containing molecular sieves. The reaction that occurs is the reaction between alkanes (especially isopentane) and olefins (mostly pentene) to form (C10) alkanes. The reaction mainly occurs within the pores of the molecular sieve.

[0012] One of the objectives of this invention is to provide an alkane-to-olefin catalyst comprising a first molecular sieve, a second molecular sieve, and an optional binder, wherein the first molecular sieve is an EMT molecular sieve, and the second molecular sieve is selected from at least one of 12-membered ring-channel molecular sieves other than an EMT molecular sieve.

[0013] In a preferred embodiment, the second molecular sieve is selected from at least one of FAU molecular sieve, BEA molecular sieve, and MOR molecular sieve.

[0014] In a further preferred embodiment, the second molecular sieve is a BEA molecular sieve.

[0015] Preferably, a combination of EMT and BEA, along with an optional binder, is used as the catalyst for deolefination from alkane feedstock.

[0016] In a preferred embodiment, the binder is selected from at least one of alumina, silicon dioxide, zirconium oxide, and titanium dioxide.

[0017] In a preferred embodiment, the total weight content of the first molecular sieve and the second molecular sieve in the catalyst is 5 to 100 wt%, preferably 10 to 90 wt%.

[0018] For example, in the catalyst, the total weight content of the first molecular sieve and the second molecular sieve is 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, or 100 wt%.

[0019] In a preferred embodiment, the weight ratio of the first molecular sieve to the second molecular sieve in the catalyst is 5:1 to 1 / 5:1, preferably 3:1 to 1 / 3:1.

[0020] For example, in the catalyst, the weight ratio of the first molecular sieve to the second molecular sieve is 5:1, 4:1, 3:1, 2:1, 1:1, 4 / 5:1, 3 / 5:1, 2 / 5:1 or 1 / 5:1.

[0021] In a preferred embodiment, the first molecular sieve is a carbon-containing EMT molecular sieve, wherein the carbon content is 0.02-0.5 wt% and the Na2O content is less than 2.5 wt%.

[0022] In a preferred embodiment, the first molecular sieve is a carbon-containing EMT molecular sieve, wherein the carbon content is 0.02-0.2 wt% and the Na2O content is less than 1 wt%.

[0023] For example, the carbon content in EMT molecular sieves is 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.12 wt%, 0.15 wt%, 0.18 wt%, or 0.2 wt%.

[0024] In a preferred embodiment, in the first molecular sieve, the ratio of the amount of weak acid to the amount of medium-strong acid in the molecular sieve, based on the NH3-TPD result, is (1.05-1.5):1, preferably (1.05-1.3):1.

[0025] For example, in the first molecular sieve, based on the NH3-TPD results, the ratio of the amount of weak acid to the amount of medium-strong acid in the molecular sieve is 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1 or 1.3:1.

[0026] Most existing deolefin catalysts are used to remove olefins from aromatic feedstocks. The processes involved are of three types: 1. Utilizing the adsorption function of clay (such as kaolin); 2. Hydrogen saturation of olefins and hydrogen on a hydrogenation catalyst; 3. Under gas-free conditions, olefins act as alkylating agents, reacting with aromatics to produce heavy components.

[0027] The present invention removes alkenes from alkanes (e.g., isopentane) by reacting alkanes (e.g., isopentane) with alkenes (mostly pentene) to form (C10) alkanes, and the reaction occurs within the pores of a molecular sieve.

[0028] A second objective of this invention is to provide a method for preparing an alkane-olefin reducing catalyst, preferably used to prepare the alkane-olefin reducing catalyst described in one objective of this invention. The preparation method includes: mixing a first molecular sieve, a second molecular sieve, and an optional binder in the amounts specified therein to obtain the catalyst.

[0029] In a preferred embodiment, the second molecular sieve is selected from at least one of FAU molecular sieve, BEA molecular sieve, and MOR molecular sieve.

[0030] In a further preferred embodiment, the second molecular sieve is a BEA molecular sieve.

[0031] Preferably, a combination of EMT and BEA, along with an optional binder, is used as the catalyst for deolefination from alkane feedstock.

[0032] In a preferred embodiment, the binder is selected from at least one of alumina, silicon dioxide, zirconium oxide, and titanium dioxide.

[0033] In a preferred embodiment, the total weight content of the first molecular sieve and the second molecular sieve in the catalyst is 5 to 100 wt%, preferably 10 to 90 wt%.

[0034] For example, in the catalyst, the total weight content of the first molecular sieve and the second molecular sieve is 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, or 100 wt%.

[0035] In a preferred embodiment, the weight ratio of the first molecular sieve to the second molecular sieve in the catalyst is 5:1 to 1 / 5:1, preferably 3:1 to 1 / 3:1.

[0036] In a preferred embodiment, the EMT molecular sieve is obtained using a method comprising the following steps:

[0037] (1) Mix aluminum source, sodium hydroxide, silicon source, organic amine and solvent to obtain a mixture;

[0038] (2) The mixture is crystallized, and after crystallization, the solvent is removed, the mixture is washed with water, and dispersed in acid to obtain a dispersion.

[0039] (3) The dispersion is crystallized, and the solvent is removed and the mixture is washed with water after crystallization.

[0040] (4) Drying and calcining to obtain the EMT molecular sieve.

[0041] In this invention, the introduction of organic amines into the raw material solution serves several purposes: ① It replaces a portion of the sodium hydroxide, meaning the amount of sodium hydroxide used is less than in existing technologies, facilitating subsequent sodium exchange; ② The organic amines form residual carbon within the EMT molecular sieve after the subsequent crystallization process; ③ While adjusting the pH of the dispersion in step 3 using organic acids, the organic amine derivatives work together to control the carbon content of the molecular sieve. Furthermore, this invention adds organic amines during the in-situ synthesis of the molecular sieve, ensuring uniform distribution of the organic amines within the pores of the molecular sieve.

[0042] In a preferred embodiment, the aluminum source is selected from at least one of aluminum sol, sodium aluminate, aluminum sulfate, aluminum nitrate, and aluminum isopropoxide.

[0043] In a further preferred embodiment, the aluminum source is selected from at least one of aluminum sol and sodium aluminate.

[0044] In a preferred embodiment, the silicon source is selected from at least one of silica sol, water glass, tetraethyl orthosilicate, and sodium silicate.

[0045] In a further preferred embodiment, the silicon source is selected from at least one of silica sol and sodium silicate.

[0046] In a preferred embodiment, the organic amine is a small molecule organic amine.

[0047] In a further preferred embodiment, the organic amine is selected from small molecule organic amines of C1 to C6, preferably from small molecule organic amines of C1 to C4.

[0048] For example, the small molecule refers to a molecular weight of less than 200, preferably less than 100; the organic amine is selected from at least one of methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, and butylenediamine.

[0049] The reason why this invention preferably uses small molecule organic amines is that high carbon organic amines (such as organic amines with more than C7) are relatively weak in basicity and are not easy to replace sodium hydroxide.

[0050] In a preferred embodiment, the solvent is water.

[0051] In a preferred embodiment, the molar ratio of aluminum source, silicon source, sodium oxide, organic amine, and solvent is 1:(1-20):(2-10):(0.5-20):(100-500), wherein the molar amount of aluminum source is calculated as the molar amount of Al2O3, the molar amount of silicon source is calculated as the molar amount of SiO2, the molar amount of sodium oxide is the total amount including the molar amounts of sodium oxide (Na2O) in the aluminum source and silicon source and the molar amounts of sodium hydroxide converted to sodium oxide (Na2O), and the molar amounts of organic amine and solvent are respectively calculated as the molar amounts of their molecules.

[0052] In a further preferred embodiment, the molar ratio of aluminum source, silicon source, sodium oxide, organic amine and solvent is 1:(3-10):(3-8):(1-10):(150-400), wherein the molar amount of aluminum source is calculated as the molar amount of Al2O3, the molar amount of silicon source is calculated as the molar amount of SiO2, the molar amount of sodium oxide is the total amount including the molar amount of sodium oxide (Na2O) in aluminum source and silicon source and the molar amount of sodium hydroxide converted to sodium oxide (Na2O), and the molar amounts of organic amine and solvent are respectively calculated as the molar amount of their molecules.

[0053] For example, the molar ratio of aluminum source to silicon source is 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10; the molar ratio of aluminum source to sodium oxide is 1:3, 1:4, 1:5, 1:6, 1:7 or 1:8; the molar ratio of aluminum source to organic amine is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10; and the molar ratio of aluminum source to solvent is 1:150, 1:200, 1:250, 1:300, 1:350 or 1:400.

[0054] In a preferred embodiment, step (1) is performed as follows:

[0055] (1.1) Mix the aluminum source, sodium hydroxide and solvent to obtain solution A;

[0056] (1.2) Mix the silicon source, organic amine, and solvent to obtain solution B;

[0057] (1.3) Cool solutions A and B, then slowly add solution A to solution B to obtain the mixture.

[0058] In a preferred embodiment, the weight concentration of solution A is 3-35 wt%, preferably 4-30 wt%.

[0059] In a preferred embodiment, the weight concentration of solution B is 25-50 wt%, preferably 28-48 wt%.

[0060] In a preferred embodiment, in step (1.3), the temperature is cooled to -10 to 10°C, preferably to 0 to 4°C.

[0061] In a preferred embodiment, the crystallization in step (2) is carried out at 5–60°C for 0.5–8 days.

[0062] In a further preferred embodiment, the crystallization in step (2) is carried out at 10–40°C for 1–5 days.

[0063] The crystallization described in step (2) is carried out at 10°C, 20°C, 30°C or 40°C for 1, 2, 3, 4 or 5 days.

[0064] In a preferred embodiment, in step (2), the solvent is removed by vacuum filtration.

[0065] In a preferred embodiment, in step (2), the filtrate is washed with water until the pH of the filtrate is 9-10.

[0066] For example, in step (2), the filtrate is washed with water until the pH of the filtrate is 9, 9.5 or 10.

[0067] In step (2), if the pH is controlled to be below 9, the amount of organic amine will be too low. For example, the organic amine may be washed away by water, resulting in insufficient organic amine in the molecular sieve system.

[0068] In a preferred embodiment, in step (2), the acid is an organic acid.

[0069] In a further preferred embodiment, the organic acid is selected from at least one of formic acid, acetic acid, propionic acid, citric acid, oxalic acid, benzoic acid, and tartaric acid.

[0070] In contrast to the inorganic acids used in existing technologies, this invention uses organic acids because some organic acids will form residual carbon after crystallization and remain inside the molecular sieve.

[0071] In a further preferred embodiment, the pH value of the dispersion is adjusted to 1-5, preferably 2-4, using the acid.

[0072] For example, the pH of the dispersion is adjusted to 2, 2.5, 3, 3.5 or 4 using the acid.

[0073] In a preferred embodiment, in step (3), the crystallization is carried out at 100-300°C for 1-30 hours.

[0074] In a further preferred embodiment, in step (3), the crystallization is carried out at 130–250°C for 4–24 hours.

[0075] For example, in step (3), the crystallization is carried out at 130°C, 150°C, 180°C, 200°C, 230°C or 250°C for 4h, 6h, 10h, 12h, 15h, 18h, 20h, 22h or 24h.

[0076] In a preferred embodiment, in step (3), the solvent is removed by vacuum filtration.

[0077] In a preferred embodiment, in step (3), the filtrate is washed with water until the pH of the filtrate is 6 to 8, for example, pH = 7.

[0078] In a preferred embodiment, in step (4), the drying temperature is 50-150°C, preferably 80-120°C.

[0079] For example, in step (4), the drying temperature is 50°C, 80°C, 100°C, 120°C or 150°C.

[0080] In a preferred embodiment, in step (4), the calcination temperature is 400-650°C, preferably 500-550°C.

[0081] For example, in step (4), the roasting temperature is 400°C, 450°C, 500°C, 550°C, 600°C or 650°C.

[0082] The third objective of this invention is to provide an alkane-olefin degrading catalyst obtained by the preparation method described in the second objective of this invention.

[0083] The fourth objective of this invention is to provide the application of the alkane deolefination catalyst described in the first objective of this invention or the alkane deolefination catalyst obtained by the preparation method described in the second objective of this invention in the deolefination of alkane, especially in the deolefination of isopentane.

[0084] The fifth objective of this invention is to provide a method for reducing olefins in alkanes (especially isopentane), comprising: reacting an alkane feedstock (especially isopentane feedstock) with a catalyst, wherein the catalyst is an alkane-reducing catalyst as described in the first objective of this invention or an alkane-reducing catalyst obtained by the preparation method described in the second objective of this invention.

[0085] In a preferred embodiment, the reaction temperature is 60℃-180℃ and the pressure is 0.5MPa-10.0MPa.

[0086] In a further preferred embodiment, the reaction temperature is 80–140°C and the pressure is 1.5–3.0 MPa.

[0087] For example, the reaction temperature is 60°C, 80°C, 100°C, 120°C, 150°C, or 180°C; the pressure is 0.5MPa, 1MPa, 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa, or 3.0MPa.

[0088] Using the method described in this invention, the bromine index of the product is reduced by more than 90% compared to that of alkane feedstocks, especially isopentane feedstocks.

[0089] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0090] Compared with the prior art, the present invention has the following beneficial effects:

[0091] (1) The EMT molecular sieve has a low silica-alumina ratio, abundant active sites, a moderate ratio of weak acid and medium-strong acid, and a suitable acid distribution, and can be used under high air velocity conditions.

[0092] (2) The EMT molecular sieve used in the catalyst of the present invention has carbon residue and the Na content in the molecular sieve (calculated as Na2O content characterized by XRF) is low.

[0093] (3) The present invention preferably uses carbon-containing EMT molecular sieves and BEA molecular sieves as catalyst active components, which has the advantages of large raw material processing capacity and long service life.

[0094] (4) The catalyst described in this invention can be applied to alkanes to reduce olefins, reducing the bromine index by more than 90%. Detailed Implementation

[0095] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0096] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0097] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0098] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0099] [Example 1] Preparation of catalyst

[0100] Sodium aluminate and sodium hydroxide were dissolved in distilled water to obtain solution A, with a mass concentration of 11.5 wt%. Silica sol (SiO2 weight percentage 40%), ethylenediamine, and water were mixed and stirred until homogeneous to obtain solution B, with a mass concentration of 29.1 wt%. Solutions A and B were cooled separately in an ice bath at 4°C. Then, solution A was slowly added to solution B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled at Al2O3:SiO2:Na2O:ethylenediamine:H2O = 1:5.3:3.7:3.3:180. The mixture was crystallized at 30°C for 3 days to obtain a suspension. This suspension was filtered under reduced pressure and washed with distilled water until the pH reached 10. The filter cake was dispersed in water, and oxalic acid was added to adjust the pH to 3. The dispersion was crystallized at 230℃ for 12 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-1). The Si / Al ratio was 1.5, the carbon content was 0.10 wt%, and the Na2O content was 0.83 wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 1.08:1.

[0101] Na-β molecular sieve with Si / Al2 = 50 was exchanged to obtain NH4-β molecular sieve. EMT-1, NH4-β molecular sieve and alumina were shaped and calcined according to formulations of 30%, 50% and 20% by weight (dry basis) to obtain catalyst EB-1.

[0102] [Example 2] Preparation of catalyst

[0103] Aluminum sulfate and sodium hydroxide were dissolved in distilled water to obtain solution A, with a mass concentration of 24.8 wt%. Sodium silicate, propylenediamine, and water were mixed and stirred until homogeneous to obtain solution B, with a mass concentration of 45.9 wt%. Solutions A and B were cooled separately in an ice bath at 4°C. Then, solution A was slowly added to solution B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled to be Al₂O₃:SiO₂:Na₂O:propylenediamine:H₂O = 1:5.0:6.9:3.7:240. The mixture was crystallized at 30°C for 3 days to obtain a suspension. The suspension was filtered under reduced pressure and washed with distilled water until the pH reached 9.5. The filter cake was dispersed in water, and citric acid was added to adjust the pH to 4. The dispersion was crystallized at 200℃ for 24 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-2). The Si / Al ratio was 1.2, the carbon content was 0.07wt%, and the Na2O content was 0.95wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 1.05:1.

[0104] Na-β molecular sieve with Si / Al2 = 50 was exchanged to obtain NH4-β molecular sieve. EMT-2, NH4-β molecular sieve and alumina were shaped and calcined according to a formula of 40%, 40% and 20% by weight (dry basis) to obtain catalyst EB-2.

[0105] [Example 3] Preparation of Catalyst

[0106] Sodium aluminate and sodium hydroxide were dissolved in distilled water to obtain solution A, with a mass concentration of 10.7 wt%. Sodium silicate, ethylenediamine, and water were mixed and stirred until homogeneous to obtain solution B, with a mass concentration of 34.1 wt%. Solutions A and B were cooled separately in an ice bath at 4°C. Then, solution A was slowly added to solution B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled to be Al₂O₃:SiO₂:Na₂O:ethylenediamine:H₂O = 1:5.2:7.2:4.8:300. The mixture was crystallized at 30°C for 3 days to obtain a suspension. The suspension was filtered under reduced pressure and washed with distilled water until the pH reached 10. The filter cake was dispersed in water, and oxalic acid was added to adjust the pH to 2. The dispersion was crystallized at 230℃ for 24 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-3). The Si / Al ratio was 1.3, the carbon content was 0.16 wt%, and the Na2O content was 0.79 wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 1.22:1.

[0107] Na-β molecular sieve with Si / Al2 = 50 was exchanged to obtain NH4-β molecular sieve. EMT-3, NH4-β molecular sieve and alumina were shaped and calcined according to formulations of 50%, 30% and 20% by weight (dry basis) to obtain catalyst EB-3.

[0108] [Example 4] Preparation of Catalyst

[0109] Aluminum sol (Al₂O₃ weight percentage 24%) and sodium hydroxide were dissolved in distilled water to obtain solution A, with a mass concentration of 4.1 wt%. Sodium silicate, butanediamine, and water were mixed and stirred until homogeneous to obtain solution B, with a mass concentration of 42.8 wt%. Solutions A and B were cooled separately in an ice bath at 4°C. Then, solution A was slowly added to solution B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled to be Al₂O₃:SiO₂:Na₂O:butanediamine:H₂O = 1:5.1:6.6:5:270. The mixture was crystallized at 30°C for 3 days to obtain a suspension. The suspension was filtered under reduced pressure and washed with distilled water until the pH reached 9. The filter cake was dispersed in water, and acetic acid was added to adjust the pH to 3. The dispersion was crystallized at 250℃ for 12 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-4). The Si / Al ratio was 1.7, the carbon content was 0.12 wt%, and the Na2O content was 0.74 wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 1.15:1.

[0110] Na-β molecular sieve with Si / Al2 = 50 was exchanged to obtain NH4-β molecular sieve. EMT-4, NH4-β molecular sieve and alumina were shaped and calcined according to formulations of 20%, 60% and 20% by weight (dry basis) to obtain catalyst EB-4.

[0111] [Example 5] Preparation of EMT molecular sieves

[0112] Sodium aluminate and sodium hydroxide were dissolved in distilled water to obtain solution A, with a mass concentration of 10.7 wt%. Sodium silicate, an aqueous solution of ethylamine (ethylamine content 65-70%), and water were mixed and stirred until homogeneous to obtain solution B, with a mass concentration of 34.8 wt%. Solutions A and B were cooled separately in an ice bath at 4°C. Then, under magnetic stirring, solution A was slowly added to solution B to form a mixture. The molar ratio of the mixture was controlled to be Al₂O₃:SiO₂:Na₂O:ethylamine:H₂O = 1:5.2:7.2:10:300. The mixture was crystallized at 30°C for 3 days to obtain a suspension. The suspension was filtered under reduced pressure and washed with distilled water until the pH reached 10. The filter cake was dispersed in water, and oxalic acid was added to adjust the pH to 2. The dispersion was crystallized at 230℃ for 24 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-5). The Si / Al ratio was 1.8, the carbon content was 0.19 wt%, and the Na2O content was 0.66 wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 1.11:1.

[0113] Na-β molecular sieve with Si / Al2 = 50 was exchanged to obtain NH4-β molecular sieve. EMT-5, NH4-β molecular sieve and alumina were shaped and calcined according to formulations of 20%, 60% and 20% by weight (dry basis) to obtain catalyst EB-5.

[0114] [Example 6] Method for reducing olefins from alkane

[0115] A deolefination test was conducted using 5g of EB-1 in a fixed-bed reactor with isopentane feedstock containing 500ppm olefins. The reaction pressure was 2.0MPa, the reaction temperature was 100℃, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 11 ppm; after 240 hours of reaction, the olefin content in the product was 28 ppm, indicating that the EB-1 catalyst has stable deolefin removal performance under high space velocity conditions.

[0116] [Example 7] Method for reducing olefins from alkane

[0117] A deolefination test was conducted in a fixed-bed reactor using 5 g of EB-2 with isopentane feedstock containing 500 ppm olefins. The reaction pressure was 2.0 MPa, the reaction temperature was 120 °C, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 13 ppm; after 240 hours of reaction, the olefin content in the product was 35 ppm, indicating that the EB-2 catalyst has stable deolefin removal performance under high space velocity conditions.

[0118] [Example 8] Method for reducing olefins from alkane

[0119] A deolefination test was conducted using 5g of EB-3 in a fixed-bed reactor with isopentane feedstock containing 500ppm olefins. The reaction pressure was 2.0MPa, the reaction temperature was 140℃, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 6 ppm; after 240 hours of reaction, the olefin content in the product was 21 ppm, indicating that the EB-3 catalyst has stable deolefin removal performance under high space velocity conditions.

[0120] [Example 9] Method for reducing olefins from alkane

[0121] A deolefination test was conducted using 5g of EB-4 in a fixed-bed reactor with isopentane feedstock containing 500ppm olefins. The reaction pressure was 2.0MPa, the reaction temperature was 100℃, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 10 ppm; after 240 hours of reaction, the olefin content in the product was 44 ppm, indicating that the EB-4 catalyst has stable deolefin removal performance under high space velocity conditions.

[0122] [Example 10] Method for reducing olefins from alkane

[0123] A deolefination test was conducted on isopentane feedstock containing 500 ppm olefins using 5 g of EB-5 in a fixed-bed reactor. The reaction pressure was 2.0 MPa, the reaction temperature was 140 °C, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 17 ppm; after 240 hours of reaction, the olefin content in the product was 48 ppm, indicating that the EB-5 catalyst has stable deolefin removal performance under high space velocity conditions.

[0124] Comparative Example 1

[0125] The process of Example 1 was repeated, except that in the preparation of EMT molecular sieves, organic amines were not used, and only sodium hydroxide was used to adjust the alkalinity.

[0126] Sodium aluminate and sodium hydroxide were dissolved in distilled water to obtain solution A. Silica sol (40% SiO2 by weight), sodium hydroxide, and water were mixed and stirred until homogeneous to obtain solution B. Solutions A and B were cooled separately in an ice bath at 4°C. Then, solution A was slowly added to solution B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled at Al₂O₃:SiO₂:Na₂O:H₂O = 1:5.3:17.8:180. The mixture was crystallized at 30°C for 3 days to obtain a suspension. This suspension was filtered under reduced pressure and washed with distilled water until the pH reached 10. The filter cake was dispersed in water, and oxalic acid was added to adjust the pH to 3. The dispersion was crystallized at 230℃ for 12 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-5). The Si / Al ratio was 1.2, the carbon content was 0.04 wt%, and the Na2O content was 6.55 wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 0.84:1.

[0127] Na-β with Si / Al2 = 50 was exchanged to obtain NH4-β molecular sieve. EMT-5, NH4-β molecular sieve and alumina were shaped and calcined according to formulations of 30%, 50% and 20% by weight (dry basis) to obtain catalyst EB-5.

[0128] A deolefination test was conducted using 5g of EB-5 in a fixed-bed reactor with isopentane feedstock containing 500ppm olefins. The reaction pressure was 2.0MPa, the reaction temperature was 100℃, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 427 ppm; after 240 hours of reaction, the olefin content in the product was 500 ppm, indicating that the EB-5 catalyst has low deolefination activity.

[0129] Comparative Example 2

[0130] Repeat the process of Example 1, except that the C1-C4 organic amines are replaced with an equal amount of octanediamine.

[0131] Sodium aluminate and sodium hydroxide were dissolved in distilled water to obtain solution A; silica sol (SiO2 weight percentage 40%), octanediamine, and water were mixed and stirred until homogeneous to obtain solution B; solutions A and B were cooled separately in an ice bath at 4°C, and then A was slowly added to B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled at Al2O3:SiO2:Na2O:octanediamine:H2O = 1:5.3:3.7:3.3:180. The mixture was crystallized at 30°C for 3 days to obtain a suspension, which was then filtered under reduced pressure and washed with distilled water until the pH reached 10. XRD characterization of the dried sample showed that the product was amorphous and lacked the characteristic diffraction peaks of EMT molecular sieves.

[0132] Comparative Example 3

[0133] Repeat the process of Example 1, except that the pH is adjusted to 8 in step (2).

[0134] Sodium aluminate and sodium hydroxide were dissolved in distilled water to obtain solution A. Silica sol (SiO2 weight percentage 40%), ethylenediamine, and water were mixed and stirred until homogeneous to obtain solution B. Solutions A and B were cooled separately in an ice bath at 4°C. Then, solution A was slowly added to solution B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled to be Al2O3:SiO2:Na2O:ethylenediamine:H2O = 1:5.3:3.7:3.3:180. The mixture was crystallized at 30°C for 3 days to obtain a suspension. This suspension was filtered under reduced pressure and washed with distilled water until the pH reached 8. The filter cake was dispersed in water, and oxalic acid was added to adjust the pH to 3. The dispersion was crystallized at 230℃ for 12 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-6). The Si / Al ratio was 1.5, the carbon content was 0.01 wt%, and the Na2O content was 0.80 wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 1.02:1.

[0135] Na-β with Si / Al2 = 50 was exchanged to obtain NH4-β. EMT-6, NH4-β and alumina were shaped and calcined according to formulations of 30%, 50% and 20% by weight (dry basis) to obtain catalyst EB-6.

[0136] A deolefination test was conducted in a fixed-bed reactor using 5 g of EB-6 on an isopentane feedstock containing 500 ppm olefins. The reaction conditions were: reaction pressure 2.0 MPa, reaction temperature 100 °C, and space velocity 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 10 ppm; after 240 hours of reaction, the olefin content in the product was 76 ppm, indicating that the EB-6 catalyst has high initial activity for deolefin removal, but poor stability.

[0137] Comparative Example 4

[0138] Repeat the process of Example 1, except that an equal amount of hydrochloric acid is used to replace the organic acid.

[0139] Sodium aluminate and sodium hydroxide were dissolved in distilled water to obtain solution A. Silica sol (SiO2 weight percentage 40%), ethylenediamine, and water were mixed and stirred until homogeneous to obtain solution B. Solutions A and B were cooled separately in an ice bath at 4°C. Then, solution A was slowly added to solution B under magnetic stirring to form a mixture. The molar ratio of the mixture was controlled to be Al2O3:SiO2:Na2O:ethylenediamine:H2O = 1:5.3:3.7:3.3:180. The mixture was crystallized at 30°C for 3 days to obtain a suspension. This suspension was filtered under reduced pressure and washed with distilled water until the pH reached 10. The filter cake was dispersed in water, and hydrochloric acid was added to adjust the pH to 3. The dispersion was crystallized at 230℃ for 12 hours. After crystallization, it was filtered under reduced pressure and washed with distilled water until the pH reached 7. The filter cake was dried at 120℃ and calcined at 550℃ for 3 hours to obtain a carbon-containing EMT molecular sieve (named EMT-7). The Si / Al ratio was 1.3, the carbon content was 0.03 wt%, and the Na2O content was 3.17 wt%. Based on the NH3-TPD results, the ratio of weak acid content to medium-strong acid content in the carbon-containing EMT molecular sieve catalyst was 0.83:1.

[0140] Na-β molecular sieve with Si / Al2 = 50 was exchanged to obtain NH4-β molecular sieve. EMT-7, NH4-β molecular sieve and alumina were shaped and calcined according to formulations of 30%, 50% and 20% by weight (dry basis) to obtain catalyst EB-7.

[0141] A deolefination test was conducted in a fixed-bed reactor using 5g of EB-7 on an isopentane feedstock containing 500ppm olefins. The reaction pressure was 2.0MPa, the reaction temperature was 100℃, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 171 ppm; after 240 hours of reaction, the olefin content in the product was 500 ppm, indicating that the EB-7 catalyst had poor initial activity and stability in deolefin removal.

[0142] Comparative Example 5

[0143] The process of Example 1 is repeated, except that an equal amount of BEA molecular sieve is used to replace the EMT molecular sieve.

[0144] Na-β with Si / Al2 = 50 was exchanged to obtain NH4-β. NH4-β and alumina were shaped and calcined according to a formulation of 80% and 20% by weight (dry basis) to obtain catalyst EB-8.

[0145] A deolefination test was conducted in a fixed-bed reactor using 5g of EB-8 on an isopentane feedstock containing 500ppm olefins. The reaction pressure was 2.0MPa, the reaction temperature was 100℃, and the space velocity was 10.0 h⁻¹. -1After 72 hours of reaction, the olefin content in the product was 37 ppm; after 240 hours of reaction, the olefin content in the product was 89 ppm, indicating that the EB-8 catalyst had low initial activity in deolefin removal.

[0146] Comparative Example 6

[0147] The process of Example 1 was repeated, except that an equal amount of EMT was used to replace the BEA molecular sieve.

[0148] The EMT-1 prepared in Example 1 was shaped and calcined with NH4-β and alumina according to a formulation of 80% and 20% by weight (dry basis) to obtain catalyst EB-9.

[0149] A deolefination test was conducted on isopentane feedstock containing 500 ppm olefins using 5 g of EB-9 in a fixed-bed reactor. The reaction pressure was 2.0 MPa, the reaction temperature was 100 °C, and the space velocity was 10.0 h⁻¹. -1 After 72 hours of reaction, the olefin content in the product was 8 ppm; after 240 hours of reaction, the olefin content in the product was 75 ppm, indicating that the EB-9 catalyst has high initial activity for deolefin removal, but low stability.

[0150] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. An alkane-to-olefin catalyst, comprising a first molecular sieve, a second molecular sieve, and an optional binder, wherein, The first molecular sieve is an EMT molecular sieve, and the second molecular sieve is selected from at least one of the 12-membered ring molecular sieves other than the EMT molecular sieve; the first molecular sieve is a carbon-containing EMT molecular sieve with a carbon content of 0.02~0.5wt% and a Na2O content of less than 2.5wt%; in the first molecular sieve, based on NH3-TPD results, the ratio of the weak acid content to the medium strong acid content of the molecular sieve is (1.05-1.5):1; the second molecular sieve is selected from at least one of the FAU molecular sieve, BEA molecular sieve, and MOR molecular sieve, and in the catalyst, the weight ratio of the first molecular sieve to the second molecular sieve is 5:1 to 1 / 5:

1.

2. The alkane-to-olefin catalyst according to claim 1, characterized in that, The binder is selected from at least one of alumina, silicon dioxide, zirconium oxide, and titanium dioxide.

3. The alkane-to-olefin catalyst according to claim 1, characterized in that, In the catalyst, the total weight content of the first molecular sieve and the second molecular sieve is 5~100wt%.

4. The alkane-to-olefin catalyst according to claim 1, characterized in that, In the catalyst, the total weight content of the first molecular sieve and the second molecular sieve is 10~90 wt%; and / or, In the catalyst, the weight ratio of the first molecular sieve to the second molecular sieve is 3:1 to 1 / 3:

1.

5. The alkane-to-olefin catalyst according to any one of claims 1 to 4, characterized in that, in: The carbon content is 0.02~0.2wt%; and / or, The Na2O content is less than 1 wt%.

6. The alkane-to-olefin catalyst according to claim 5, characterized in that, In the first molecular sieve, based on the NH3-TPD results, the ratio of the weak acid content to the medium strong acid content of the molecular sieve is (1.05-1.3):

1.

7. A method for preparing an alkane-to-olefin catalyst, used to prepare the alkane-to-olefin catalyst according to any one of claims 1 to 6, the preparation method comprising: The catalyst is obtained by mixing the first molecular sieve, the second molecular sieve, and an optional binder in the stated amounts. The EMT molecular sieve is obtained using a method comprising the following steps: (1) Mix aluminum source, sodium hydroxide, silicon source, organic amine and solvent to obtain a mixture; (2) The mixture is crystallized, and after crystallization, the solvent is removed, the mixture is washed with water until the pH of the filtrate is 9-10, and then dispersed in acid to obtain a dispersion. (3) The dispersion is crystallized, and the solvent is removed and the mixture is washed with water after crystallization. (4) Dry and calcine to obtain the EMT molecular sieve.

8. The preparation method according to claim 7, characterized in that, The second molecular sieve is selected from at least one of FAU molecular sieve, BEA molecular sieve, and MOR molecular sieve; and / or, The binder is selected from at least one of alumina, silicon dioxide, zirconium oxide, and titanium dioxide; and / or, In the catalyst, the total weight content of the first molecular sieve and the second molecular sieve is 5~100 wt%; and / or, In the catalyst, the weight ratio of the first molecular sieve to the second molecular sieve is 5:1 to 1 / 5:

1.

9. The preparation method according to claim 8, characterized in that, The second molecular sieve is a BEA molecular sieve; and / or, The binder is selected from at least one of alumina, silicon dioxide, zirconium oxide, and titanium dioxide; and / or, In the catalyst, the total weight content of the first molecular sieve and the second molecular sieve is 10~90 wt%; and / or, In the catalyst, the weight ratio of the first molecular sieve to the second molecular sieve is 3:1 to 1 / 3:

1.

10. The preparation method according to claim 7, characterized in that, The aluminum source is selected from at least one of aluminum sol, sodium aluminate, aluminum sulfate, aluminum nitrate, and aluminum isopropoxide; and / or, The silicon source is selected from at least one of silica sol, water glass, tetraethyl orthosilicate, and sodium silicate; and / or, The solvent is water.

11. The preparation method according to claim 7, characterized in that, The organic amine is a small molecule organic amine.

12. The preparation method according to claim 7, characterized in that, The organic amine is selected from small molecule organic amines of C1 to C6.

13. The preparation method according to claim 7, characterized in that, The organic amine is selected from small molecule organic amines of C1 to C4.

14. The preparation method according to claim 7, characterized in that, The molar ratio of aluminum source, silicon source, sodium oxide, organic amine and solvent is 1:(1~20):(2~10):(0.5~20):(100~500); wherein, the molar amount of aluminum source is calculated as the molar amount of Al2O3, the molar amount of silicon source is calculated as the molar amount of SiO2, the molar amount of sodium oxide is the total amount including the molar amount of sodium oxide in aluminum source and silicon source and the molar amount of sodium hydroxide converted to sodium oxide, and the molar amounts of organic amine and solvent are calculated as the molar amount of their molecules.

15. The preparation method according to claim 7, characterized in that, The molar ratio of aluminum source, silicon source, sodium oxide, organic amine and solvent is 1:(3~10):(3~8):(1~10):(150~400); wherein, the molar amount of aluminum source is calculated as the molar amount of Al2O3, the molar amount of silicon source is calculated as the molar amount of SiO2, the molar amount of sodium oxide is the total amount including the molar amount of sodium oxide in aluminum source and silicon source and the molar amount of sodium hydroxide converted to sodium oxide, and the molar amounts of organic amine and solvent are calculated as the molar amount of their molecules.

16. The preparation method according to claim 7, characterized in that, Step (1) is performed as follows: (1.1) Mix the aluminum source, sodium hydroxide and solvent to obtain solution A; (1.2) Mix the silicon source, organic amine, and solvent to obtain solution B; (1.3) Cool solutions A and B, then add solution A to solution B to obtain the mixture.

17. The preparation method according to claim 16, characterized in that, The weight concentration of solution A is 3~35wt%; and / or, The weight concentration of solution B is 25-50 wt%; and / or, In step (1.3), the temperature is cooled to -10~10℃.

18. The preparation method according to claim 16, characterized in that, The weight concentration of solution A is 4~30 wt%; and / or, The weight concentration of solution B is 28~48 wt%; and / or, In step (1.3), the temperature is cooled to 0~4℃.

19. The preparation method according to claim 7, characterized in that, The crystallization described in step (2) is carried out at 5~60℃ for 0.5~8 days; and / or, In step (2), the solvent is removed by vacuum filtration; and / or, In step (2), the acid is an organic acid.

20. The preparation method according to claim 19, characterized in that, The organic acid is selected from at least one of formic acid, acetic acid, propionic acid, citric acid, oxalic acid, benzoic acid, and tartaric acid.

21. The preparation method according to any one of claims 7 to 20, characterized in that, In step (3), the crystallization is carried out at 100~300℃ for 1~30h; and / or, In step (3), the solvent is removed by vacuum filtration; and / or, In step (3), the filtrate is washed with water until the pH reaches 6-8; and / or, In step (4), the drying temperature is 50~150℃; and / or, In step (4), the calcination temperature is 400~650℃.

22. An alkane-to-olefin catalyst obtained by the preparation method according to any one of claims 7-21, comprising a first molecular sieve, a second molecular sieve, and an optional binder, wherein, The first molecular sieve is an EMT molecular sieve, and the second molecular sieve is selected from at least one of the 12-membered ring pore molecular sieves other than the EMT molecular sieve; the first molecular sieve is a carbon-containing EMT molecular sieve with a carbon content of 0.02~0.5wt% and a Na2O content of less than 2.5wt%; in the first molecular sieve, based on the NH3-TPD results, the ratio of the weak acid content to the medium strong acid content of the molecular sieve is (1.05-1.5):

1.

23. The application of the alkane deolefination catalyst according to any one of claims 1 to 6 or the alkane deolefination catalyst obtained by the preparation method according to any one of claims 7 to 21 in the alkane deolefination process.

24. The application according to claim 23, in the reduction of olefins by isopentane.

25. A method for reducing olefins from alkane, comprising: The alkane feedstock reacts with a catalyst, wherein the catalyst is an alkane de-olefin catalyst as described in any one of claims 1 to 6 or an alkane de-olefin catalyst obtained by the preparation method described in any one of claims 7 to 21.

26. The method according to claim 25, characterized in that, The reaction is carried out at a temperature of 60℃-180℃ and a pressure of 0.5MPa-10.0MPa.