Chain alkane isomerization catalyst, and preparation method therefor and use thereof

Abstract

Disclosed in the present application are a chain alkane isomerization catalyst, and a preparation method therefor and the use thereof. The chain alkane isomerization catalyst comprises a hydrogen-type ZSM-48 molecular sieve, an active component and a binder, wherein the hydrogen-type ZSM-48 molecular sieve has a spherical crystal structure or an ellipsoidal crystal structure; the hydrogen-type ZSM-48 molecular sieve has micropores and mesopores; the active component is loaded on the hydrogen-type ZSM-48 molecular sieve; the active component comprises an active element, and the active element is selected from at least one of nickel, cobalt, platinum and palladium; and the binder is selected from at least one of aluminum oxide, silicon oxide and clay. The chain alkane isomerization catalyst prepared by means of the method has the characteristics of high activity and a high isomer yield.

Description

A chain alkane isomerization catalyst and its preparation method and application Technical Field

[0001] The present application relates to a chain alkane isomerization catalyst and a preparation method and application thereof, belonging to the technical field of catalytic chemistry. Background Art

[0002] Isomerization of long-chain alkanes is a key process for producing high-octane gasoline, improving low-temperature performance and viscosity index of diesel and lubricating oil. This reaction usually occurs on a bifunctional catalyst, and bifunctional catalyst includes a metal and an acid support, and dehydrogenation / hydrogenation reaction is carried out on the metal position, and skeletal isomerization reaction occurs on the acidic position. Extensive studies have shown that one-dimensional mesoporous molecular sieves (ZSM-22 (TON), SAPO-11 (AEL), ZSM-23 (MTT), ZSM-48 (* MRE) etc.) are the most suitable acidic supports, and their unique one-dimensional pore structure shows higher isomer yield and better cracking ability (Zhang M, Li C, Chen X, et al.Industrial & Engineering Chemistry Research, 2016, 55, 6069-6078.). Wherein, the reaction product of ZSM-48 molecular sieve-based catalyst contains a higher proportion of intermediate branched isomeric components, which makes the product have better low-temperature performance. Theoretical calculations also show that ZSM-48 zeolite has relatively superior adsorption and activation capabilities for normal alkanes during the isomerization of long-chain alkanes. Therefore, ZSM-48 zeolite is considered one of the most promising acidic supports.

[0003] The balance and coordination of the acid center and the metal center in the bifunctional catalyst are the key to building an excellent long-chain alkane isomerization catalyst, which is mainly reflected in the concentration ratio and distance effect. The low and difficult-to-adjust acid density of ZSM-48 molecular sieve makes it difficult to give full play to the pore structure advantage, which is the main obstacle to its industrial application. In addition, the traditional rod-shaped morphology of ZSM-48 molecular sieve causes the outer surface of the catalyst to have a large number of non-selective acid sites, which also weakens the selectivity of the catalyst. In order to solve these problems, researchers have also proposed many solutions. For example, a special template agent is used to synthesize aluminum-rich ZSM-48 molecular sieve to make up for the lack of acidity (CN110127719A); Post-treatment or in-situ synthesis strategy is used to construct multi-level pore ZSM-48 molecular sieve to enhance catalyst diffusion performance (Zhang M, Li C, Chen X, et al.Industrial & Engineering Chemistry Research, 2019, 58: 19855-19861.). How to achieve simultaneous regulation of the acid density, diffusion properties and morphology of ZSM-48 zeolite to construct an excellent long-chain alkane hydroisomerization catalyst is still a topic worth exploring. Summary of the Invention

[0004] The purpose of this application is to develop a catalytic material for the isomerization of chain alkanes. The long-chain alkane isomerization catalyst obtained by this method has the characteristics of high selectivity, good catalytic activity and stability.

[0005] In one aspect of the present application, a chain alkane isomerization catalyst is provided, wherein the chain alkane isomerization catalyst comprises a hydrogen-type ZSM-48 molecular sieve, an active component and a binder;

[0006] The hydrogen-type ZSM-48 molecular sieve has a spherical crystal structure or an ellipsoidal crystal structure;

[0007] The hydrogen-type ZSM-48 molecular sieve has micropores and mesopores;

[0008] The active component is loaded on the hydrogen-type ZSM-48 molecular sieve;

[0009] The active component includes an active element, and the active element is selected from at least one of nickel, cobalt, platinum, and palladium;

[0010] The binder is selected from at least one of alumina, silica, and clay.

[0011] Optionally, the mass content of the hydrogen-type ZSM-48 molecular sieve in the chain alkane isomerization catalyst is 40 to 90 wt%.

[0012] Optionally, the mass content of the hydrogen ZSM-48 molecular sieve in the chain alkane isomerization catalyst is independently selected from any value among 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 85wt%, 90wt% or any range of values ​​between any two of the above points.

[0013] Optionally, the mass content of the active component in the chain alkane isomerization catalyst is 0.05 to 10 wt%, wherein the mass of the active component is calculated as the mass of the active element.

[0014] Optionally, the mass content of the active component in the chain alkane isomerization catalyst is independently selected from any value among 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 3.5wt%, 5wt%, 8wt%, 10wt% or any range of values ​​between any two of the above points.

[0015] Optionally, the binder has a mass content of 3 to 15 wt % in the chain alkane isomerization catalyst.

[0016] Optionally, the mass content of the binder in the chain alkane isomerization catalyst is independently selected from any value among 3wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt% or any range of values ​​between any two of the above points.

[0017] Optionally, the silicon-aluminum ratio of the hydrogenated ZSM-48 molecular sieve is 30-400.

[0018] Optionally, the silicon-aluminum ratio of the hydrogenated ZSM-48 molecular sieve is independently selected from any value among 30, 50, 100, 150, 200, 250, 300, 350, 400 or any range between any two of the above points.

[0019] Optionally, the micropore volume of the hydrogen-type ZSM-48 molecular sieve is 0.04 to 0.09 cm 3 / g, and the mesopore volume is 0.2~0.8cm 3 / g.

[0020] As a specific embodiment, the chain alkane isomerization catalyst comprises a spherical or ellipsoidal multi-level porous hydrogen-type ZSM-48 molecular sieve, a metal species and a binder, wherein the metal species is selected from at least one of nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride, chloroplatinic acid, ammonium chloroplatinate, platinum chloride, and palladium chloride.

[0021] Another aspect of the present application provides a method for preparing the above-mentioned chain alkane isomerization catalyst, which solves the above-mentioned technical problems by adopting suitable raw materials, finely adjusting the composition of the raw materials, and using hydrothermal crystallization and equal volume impregnation methods.

[0022] The preparation method comprises:

[0023] (1) After mixing the ZSM-48 molecular sieve matrix with the mother liquor, the mixture is aged for 1, hydrothermally crystallized for 1, calcined for 1, and ion exchanged to obtain the hydrogen-type ZSM-48 molecular sieve;

[0024] Wherein, the mother liquor comprises an aluminum source 1, a template 1, an inorganic base 1 and water 1;

[0025] (2) Extruding the hydrogenated ZSM-48 molecular sieve and the binder into strips and calcining them to obtain a carrier;

[0026] (3) Mixing an aqueous solution containing an active element precursor with the support, impregnating with equal volumes, and calcining III to obtain the chain alkane isomerization catalyst.

[0027] As a specific embodiment, the preparation method of the chain alkane isomerization catalyst includes:

[0028] S1. After mixing the ZSM-48 molecular sieve matrix with the mother liquor, aging and hydrothermal crystallization are carried out to obtain spherical or ellipsoidal multi-level pore ZSM-48 molecular sieve raw powder, and then roasting and ion exchange are carried out to obtain the spherical or ellipsoidal multi-level pore hydrogen-type ZSM-48 molecular sieve.

[0029] The mother solution comprises an aluminum source, a template, an inorganic base and water.

[0030] S2, then extruding the spherical or ellipsoidal multi-level pore hydrogen-type ZSM-48 molecular sieve and a binder to obtain a catalyst carrier;

[0031] S3. The metal species is prepared in the form of an aqueous solution, and the metal and the carrier are compounded by means of equal volume impregnation, and then calcined in an air atmosphere to obtain the chain alkane isomerization catalyst.

[0032] Optionally, in step (1), the microstructure of the ZSM-48 molecular sieve matrix is ​​spherical or ellipsoidal.

[0033] Optionally, the particle size of the ZSM-48 molecular sieve matrix is ​​400 to 4000 nm.

[0034] Optionally, the particle size of the ZSM-48 molecular sieve matrix is ​​500 to 3000 nm.

[0035] Optionally, the surface of the ZSM-48 molecular sieve matrix has micropores and mesopores, and the pore volume of the micropores is 0.03 to 0.09 cm 3 / g, with a total pore volume of 0.02 to 0.25 cm 3 / g.

[0036] Optionally, the silicon-to-aluminum ratio of the ZSM-48 molecular sieve matrix is ​​≥120.

[0037] Optionally, in step (1), the ion exchange procedure is as follows: adding the molecular sieve raw powder to a 1 mol / L NH4Cl solution at a liquid-to-solid mass ratio of 6 to 30, and stirring at 80°C for 1 hour. Repeat the exchange three times, filter, and wash to obtain the ammonium molecular sieve. The ammonium molecular sieve is calcined at 550°C in an air atmosphere for 4 hours to obtain the hydrogen molecular sieve catalyst.

[0038] Optionally, the preparation method of the ZSM-48 molecular sieve matrix includes:

[0039] The aqueous solution containing silicon source II, inorganic base II and template agent II is subjected to aging II and hydrothermal crystallization II to obtain the ZSM-48 molecular sieve matrix.

[0040] As a specific embodiment, the preparation method of the ZSM-48 molecular sieve matrix comprises at least the following steps:

[0041] The raw materials containing silicon source I, inorganic base I, and template agent I are mixed with water, and then aged I, hydrothermally crystallized I, washed, dried, and calcined to obtain the ZSM-48 molecular sieve matrix.

[0042] Optionally, the silicon source II is selected from at least one of white carbon black, silica sol, ethyl orthosilicate, and water glass.

[0043] Optionally, the inorganic base II is selected from at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, lithium hydroxide, and ammonia water;

[0044] The molar ratio of the inorganic base II to the silicon source II is 0.2 to 0.6, wherein the molar amount of the silicon source II is calculated based on the molar amount of SiO2 in the silicon source II, and the molar amount of the inorganic base II is calculated based on the hydroxide in the inorganic base II.

[0045] Optionally, the molar ratio of the inorganic base II to the silicon source II is independently selected from any value among 0.2, 0.25, 0.35, 0.45, 0.55, 0.6, or any range between any two of the above points.

[0046] Optionally, the concentration of the ammonia water is 25 wt%.

[0047] Optionally, the template II is selected from at least one of hexamethylammonium bromide, hexamethylammonium chloride, and hexamethylammonium hydroxide;

[0048] The molar ratio of the template II to the silicon source II is 0.02 to 0.3, wherein the molar amount of the template II is calculated based on the molar amount of hexamethylammonium in the template II, and the molar amount of the silicon source II is calculated based on the molar amount of SiO2 in the silicon source II.

[0049] Optionally, the molar ratio of the template II to the silicon source II is independently selected from any value among 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3 or any range between any two of the above points.

[0050] Optionally, the molar ratio of water to the silicon source II in the aqueous solution is 25 to 60, wherein the molar amount of the silicon source II is calculated based on the molar amount of SiO2 in the silicon source II.

[0051] Optionally, the molar ratio of water to the silicon source II in the aqueous solution is independently selected from any value among 25, 35, 45, 55, 60 or any range of values ​​between any two of the above points.

[0052] Optionally, the aqueous solution further contains an aluminum source II; the aluminum source II is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudo-boehmite, and aluminum chloride.

[0053] Optionally, the molar ratio of the silicon source II to the aluminum source II is ≥120, wherein the molar amount of the aluminum source II is calculated based on the molar amount of Al2O3 in the aluminum source II;

[0054] The conditions of the aging II are: temperature of 25 to 80° C. and time of 2 to 8 hours.

[0055] Optionally, the conditions of the hydrothermal crystallization II are: dynamic crystallization, temperature of 110-200° C., and time of 48-120 h.

[0056] The dynamic crystallization II is carried out in a kettle reactor in a rotary oven, and the rotation speed of the rotary oven is 10 to 80 r / min.

[0057] After the crystallization is completed, the template is removed by filtering, washing, and calcining at 500° C. for 6 hours to obtain the molecular sieve matrix.

[0058] Optionally, the mass ratio of the mother liquor to the ZSM-48 molecular sieve matrix is ​​5 to 70.

[0059] Optionally, the mass ratio of the mother liquor to the ZSM-48 molecular sieve matrix is ​​independently selected from any value among 5, 10, 20, 25, 30, 35, 45, 55, 65, 70 or any range of values ​​between any two of the above points.

[0060] Optionally, the aluminum source I is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudo-boehmite or aluminum chloride;

[0061] In the mother liquor, the concentration of the aluminum source I is 0.001 to 0.1 mol / L, wherein the concentration of the aluminum source I is calculated as the concentration of Al ions.

[0062] Optionally, the concentration of the aluminum source I is independently selected from any value among 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.03 mol / L, 0.4 mol / L, 0.055 mol / L, 0.07 mol / L, 0.085 mol / L, 0.1 mol / L or any range of values ​​between any two of the above points.

[0063] Optionally, the inorganic base I is selected from at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide;

[0064] In the mother liquor, the concentration of the inorganic base I is 0.1 to 0.8 mol / L, wherein the concentration of the inorganic base I is OH - concentration meter.

[0065] Optionally, the concentration of the inorganic base I is independently selected from any value among 0.1mol / L, 0.15mol / L, 0.25mol / L, 0.35mol / L, 0.45mol / L, 0.55mol / L, 0.65mol / L, 0.75mol / L, 0.8mol / L or any range of values ​​between any two of the above points.

[0066] Optionally, the template I is selected from at least one of hexamethonium bromide, hexamethonium chloride or hexamethonium hydroxide;

[0067] In the mother liquor, the concentration of the template agent I is 0.06-0.45 mol / L, wherein the concentration of the template agent I is calculated as the concentration of hexamethylammonium root.

[0068] Optionally, the concentration of the template I is independently selected from any value among 0.06mol / L, 0.08mol / L, 0.1mol / L, 0.15mol / L, 0.2mol / L, 0.25mol / L, 0.3mol / L, 0.4mol / L, 0.45mol / L or any range of values ​​between any two of the above points.

[0069] Optionally, the conditions for aging I are: temperature of 30-80° C. and time of 2-8 h.

[0070] Optionally, the temperature of the aging I is independently selected from any value among 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or any range between any two of the above points.

[0071] Optionally, the aging time I is independently selected from any value among 2h, 3h, 4h, 5h, 6h, 7h, 8h or any range of values ​​between any two of the above points.

[0072] Optionally, the conditions for the hydrothermal crystallization I are: temperature of 120-200° C., and time of 48-120 h.

[0073] Optionally, the hydrothermal crystallization I is dynamic crystallization under autogenous pressure.

[0074] Optionally, the dynamic crystallization is carried out in a tank reactor in a rotary oven;

[0075] The rotating speed of the rotary oven is 10 to 80 r / min.

[0076] Optionally, the calcination conditions are as follows: temperature of 400-600° C. and time of 1-8 h.

[0077] Optionally, the conditions for the calcination II are: temperature of 300-500° C., and time of 0.5-6 h.

[0078] As a specific embodiment, the spherical or ellipsoidal multi-level pore hydrogen-type ZSM-48 molecular sieve is mixed with a binder, extruded and calcined at 500° C. for 3 hours to obtain a catalyst carrier.

[0079] Optionally, the active element precursor is selected from at least one of nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride, chloroplatinic acid, ammonium chloroplatinate, platinum chloride, and palladium chloride.

[0080] Optionally, the calcination III is carried out under air atmosphere at a temperature of 300 to 450° C. for 1 to 3 hours.

[0081] As a specific embodiment, the metal precursor is compounded with the carrier by means of equal volume impregnation in the form of an aqueous solution, dried at room temperature, and then calcined in an air atmosphere to obtain the chain alkane isomerization catalyst.

[0082] Another aspect of the present application provides a method for isomerizing chain alkanes, and the above-mentioned chain alkanes isomerization catalyst or the chain alkanes isomerization catalyst prepared by the above-mentioned preparation method is used as a catalyst for catalyzing the chain alkanes isomerization reaction.

[0083] Optionally, the method comprises:

[0084] Under hydrogen I conditions, the raw material containing chain alkanes is contacted with the pretreated chain alkanes isomerization catalyst to react;

[0085] Wherein, the chain alkane is selected from C6~C 18 At least one of the normal chain alkanes;

[0086] The chain alkane isomerization catalyst is selected from the above-mentioned chain alkane isomerization catalysts.

[0087] As a specific embodiment, the catalyst precursor is reduced and activated under H2 atmosphere, and after activation, the temperature is lowered to the reaction temperature, and then the raw material containing chain alkane is contacted with the chain alkane isomerization catalyst to react.

[0088] Optionally, the pretreatment comprises: performing reduction activation on the chain alkane isomerization catalyst under a hydrogen II atmosphere;

[0089] The reduction activation temperature is 400-550° C., and the reduction activation time is 1-5 hours.

[0090] Optionally, the reaction temperature is 200-370°C.

[0091] The reaction pressure is 0-4 MPa;

[0092] The mass space velocity of the hydrogen I is 0.5 to 10 h -1 ;

[0093] In the reaction, the volume ratio of hydrogen I to chain alkane is 50-400.

[0094] Optionally, the reaction temperature is independently selected from any value among 200°C, 240°C, 280°C, 320°C, 340°C, 370°C or a range between any two of the above values.

[0095] Optionally, the reaction pressure is independently selected from any value among 0 MPa, 0.5 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3.5 MPa, 4 MPa, or a range between any two of the above values.

[0096] Optionally, the mass space velocity of the hydrogen I is independently selected from 0.5h -1 , 0.8h -1 , 1.2h -1 , 2.4h -1 , 3.6h -1 , 4.8h -1 , 6h -1 , 7.2h -1 , 8.4h -1 , 10h -1Any value in or a range of values ​​between any two of the above.

[0097] Optionally, the volume ratio of the hydrogen I to the chain alkane is independently selected from any value among 50, 80, 120, 160, 180, 220, 260, 280, 320, 360, 400 or a range between any two of the above.

[0098] The beneficial effects of this application include:

[0099] (1) This application provides a hierarchically porous hydrogen-type ZSM-48 molecular sieve with a spherical or ellipsoidal structure as an acidic support for a catenary alkane isomerization catalyst. The catalyst has the advantages of an adjustable silicon-aluminum ratio and good diffusion properties. Furthermore, the highly condensed spherical agglomerated morphology reduces the number of external surface acid sites, effectively improving catalytic selectivity.

[0100] (2) The chain alkane isomerization catalyst described in this application has good catalytic activity and isoalkane yield.

[0101] (3) The method used in this application is hydrothermal crystallization and conventional impregnation, and the preparation process is simple and economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] FIG1 is a standard X-ray diffraction (XRD) pattern of ZSM-48 molecular sieve and the XRD patterns of the molecular sieves prepared in Examples 1 to 5.

[0103] FIG2 is a scanning electron microscope (SEM) image of the pure phase ZSM-48 molecular sieve prepared in Example 1, with a scale of 100 nm.

[0104] FIG3 is a transmission electron microscope (TEM) image of the pure phase ZSM-48 molecular sieve prepared in Example 1 of the present application, with a scale of 0.5 μm. DETAILED DESCRIPTION

[0105] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0106] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0107] The specific information of various substances used in the examples are as follows:

[0108] Silica sol (Qingdao Ocean Chemical Co., Ltd., 30 wt% SiO2);

[0109] Silica (McLean, 95 wt% SiO2);

[0110] Tetraethyl orthosilicate (TEOS) (Kermel, >98 wt%);

[0111] Al2(SO4)3·18H2O (Sinopharm Group, 98wt%);

[0112] Al(NO3)3·9H2O (Sinopharm Group, 99wt%);

[0113] Pseudoboehmite (McLean, 66% wtAl2O3, 33 wt% H2O);

[0114] NaOH (Sinopharm Group, >96 wt%);

[0115] KOH (Kermel, 85 wt%);

[0116] HMBr (Aladdin, 98 wt%);

[0117] HMCl (Aladdin, 98 wt%)

[0118] n-Dodecane (Aladdin, 99.8wt%)

[0119] High-purity hydrogen (Dalian Institute of Chemical Physics, 99.9wt%)

[0120] Al2O3 (Sinopharm Group, analytical grade)

[0121] Deionized water (homemade).

[0122] The conversion rate and yield in the examples of this application are calculated as follows:

[0123] In the examples of the present application, a German Bruker D8 Advance X-ray diffractometer was used for XRD testing, a JEM-2100F instrument was used for TEM testing, and a JSM-7800F instrument was used for SEM testing.

[0124] Preparation Example 1 Preparation of ZSM-48 molecular sieve matrix I:

[0125] Under stirring conditions, 0.16g of Al2(SO4)3·18H2O, 1.01g of HMBr, and 0.78g of NaOH were dissolved in 37.29g of H2O. After complete dissolution, 18.26g of silica sol was added dropwise under stirring. The initial gel was aged at 45°C with stirring for 4 hours, then transferred to a stainless steel reactor and hydrothermally crystallized in a rotary oven at 160°C and 60 rpm for 48 hours. After crystallization, the product was quenched to room temperature with cold water. After filtration, washing, drying, and calcination, ZSM-48 molecular sieve precursor I was obtained with a silicon-aluminum ratio of 3:15.

[0126] The ZSM-48 molecular sieve matrix I was subjected to SEM and N2 adsorption-desorption tests, and the particle size of the ZSM-48 molecular sieve matrix I was measured to be 2 μm, and the pore volume of the micropores was 0.06 cm 3 / g, with a total pore volume of 0.10 cm 3 / g.

[0127] According to the above ratios and synthesis steps, the synthesis can be scaled up in equal proportions.

[0128] Preparation Example 2 Preparation of ZSM-48 molecular sieve matrix II:

[0129] 3.08g of HMOH and 0.20g of NaOH were dissolved in 50g of H2O with stirring. After complete dissolution, 5.84g of silica was added dropwise with stirring. The initial gel was aged at 40°C with stirring for 4 hours, then transferred to a stainless steel reactor and hydrothermally crystallized in a rotary oven at 125°C and 60 rpm for 96 hours. After crystallization, the product was quenched to room temperature with cold water. After filtration, washing, drying, and calcination, ZSM-48 molecular sieve precursor II was obtained with a silicon-aluminum ratio of 3980.

[0130] SEM and N2 adsorption-desorption tests were performed on the ZSM-48 molecular sieve matrix II. The particle size of the ZSM-48 molecular sieve matrix II was found to be 500 nm, and the pore volume of the micropores was 0.06 cm 3 / g, with a total pore volume of 0.15 cm 3 / g.

[0131] According to the above ratios and synthesis steps, the synthesis can be scaled up in equal proportions.

[0132] Example 1

[0133] 0.78g NaOH, 0.13g Al2(SO4)3·18H2O, and 2.17g HMBr were dissolved in 60g water to prepare a mother liquor. 3.00g of the ZSM-48 molecular sieve matrix I obtained in Preparation Example 1 was weighed and added to the mother liquor. Aged for 3h under stirring at 30℃, transferred to a 100ml stainless steel reactor, placed in a rotary oven, and hydrothermally crystallized at 160℃ and 60r / min for 96h. After crystallization, it was quickly cooled to room temperature with cold water, filtered, washed, and dried to obtain the sodium-type molecular sieve raw powder I. The XRD spectrum of the molecular sieve raw powder I is shown in Figure 1, which is a pure phase ZSM-48 molecular sieve. From the SEM and TEM images (Figures 2 and 3), the pure phase ZSM-48 molecular sieve is an ellipsoidal crystal with a multi-level pore structure, with a length of 4.0μm and a width of 3.0μm. The BET surface area of ​​the N2 adsorption and desorption test is 238m 2 / g, with a total pore volume of 0.32 cm 3The silicon-aluminum ratio (molar ratio of SiO2 to Al2O3) was 84 as measured by XRF.

[0134] According to the above ratios and synthesis steps, the synthesis can be scaled up in equal proportions.

[0135] The molecular sieve raw powder I was calcined at 550°C in air for 4 hours, followed by ion exchange with a 1 mol / L NH4Cl solution at 90°C for 4 hours to obtain the desired hydrogen-type molecular sieve. 20.0g of the hydrogen-type molecular sieve was extruded with 5.0g of pseudo-boehmite, dried at 120°C for 2 hours, and calcined at 550°C in air for 4 hours to obtain a catalyst support, wherein the binder was added in an amount of 15wt% of the total catalyst mass. Nickel nitrate was used as a metal precursor, and the catalyst support and metal were compounded by isovolumetric impregnation, with a metal loading of 3.5wt%. After drying at room temperature, the catalyst was calcined at 400°C in air for 3 hours. The mass of the hydrogen-type molecular sieve in the catalyst was 82.2wt% of the total catalyst mass.

[0136] Example 2

[0137] The spherical or ellipsoidal hydrogen-type ZSM-48 molecular sieve used in this embodiment is the same as that used in Example 1.

[0138] 20.0g of the hydrogen-type molecular sieve was extruded with 5.0g of pseudo-boehmite, dried at 120°C for 2h, and calcined in air at 550°C for 4h to obtain a catalyst support. The binder was added in an amount of 15wt% of the total catalyst mass. The catalyst support and metal were compounded by isovolumetric impregnation using chloroplatinic acid as a metal precursor, with a metal loading of 0.5wt%. After drying at room temperature, the mixture was calcined in air at 300°C for 3h. The mass of the hydrogen-type molecular sieve in the catalyst was 84.5wt% of the total catalyst mass.

[0139] Example 3

[0140] 2.05g KOH, 0.14g pseudo-boehmite and 2.20g HMBr were dissolved in 80g water to prepare a mother liquor. 2.67g of the ZSM-48 molecular sieve matrix I obtained in Preparation Example 1 was weighed and added to the mother liquor. Aged for 2h under stirring at 50°C, transferred to a 100ml stainless steel reactor, placed in a rotary oven, and hydrothermally crystallized for 120h at 175°C and 60r / min. After crystallization, it was suddenly cooled to room temperature with cold water, filtered, washed and dried to obtain the sodium-type molecular sieve raw powder III. The XRD spectrum of the molecular sieve raw powder III (see Figure 1) confirmed that it was a pure phase ZSM-48 molecular sieve. The morphology of the pure phase ZSM-48 molecular sieve is similar to that of Example 1, and it is an ellipsoidal crystal with a cavity structure. The BET surface area of ​​the N2 adsorption and desorption test is 308m 2 / g, with a total pore volume of 0.47 cm 3The silicon-aluminum ratio (Si / Al2) was 35 as measured by XRF.

[0141] According to the above ratios and synthesis steps, the synthesis can be scaled up in equal proportions.

[0142] The molecular sieve raw powder III was calcined at 550° C. for 4 h in an air atmosphere, and then ion-exchanged with 1 mol / L NH 4 Cl solution at 90° C. for 4 h to obtain the desired hydrogen-type molecular sieve.

[0143] 20.0g of the hydrogen-type molecular sieve was extruded with 5.0g of pseudo-boehmite, dried at 120°C for 2h, and calcined at 550°C in air for 4h to obtain a catalyst support. The binder was added in an amount of 15wt% of the total catalyst mass. Nickel nitrate was used as a metal precursor, and the catalyst support and metal were compounded by isovolumetric impregnation, with a metal loading of 5.0wt%. After drying at room temperature, the catalyst was calcined at 400°C for 3h. The mass of the hydrogen-type molecular sieve in the catalyst was 82.0wt% of the total catalyst mass.

[0144] Example 4

[0145] 0.66g KOH, 1.35g AlCl3·6H2O, and 7.56g HMOH solution were dissolved in 74.32g water to prepare a mother liquor. 2.67g of the ZSM-48 molecular sieve matrix II obtained in Preparation Example 2 was weighed and added to the mother liquor. Aged for 8h under stirring at 30°C, transferred to a 100ml stainless steel reactor, placed in a rotary oven, and hydrothermally crystallized at 145°C and 60r / min for 96h. After crystallization, it was quickly cooled to room temperature with cold water, filtered, washed, and dried to obtain the sodium-type molecular sieve raw powder IV. The XRD spectrum of the molecular sieve raw powder IV (see Figure 1) confirmed that it was a pure phase ZSM-48 molecular sieve. The morphology of the pure phase ZSM-48 molecular sieve was similar to that of Example 1, and it was a spherical crystal with a cavity structure and a crystal diameter of about 500nm. The BET surface area of ​​the N2 adsorption and desorption test was 318m 2 / g, with a total pore volume of 0.52 cm 3 The silicon-aluminum ratio (Si / Al2) was 60 as measured by XRF.

[0146] According to the above ratios and synthesis steps, the synthesis can be scaled up in equal proportions.

[0147] The molecular sieve raw powder IV was calcined at 550 ° C for 4 hours in air atmosphere, and then ion exchanged with 1 mol / L NH4Cl solution at 90 ° C for 4 hours to obtain the desired hydrogen molecular sieve.

[0148] 20.0 g of hydrogen-type molecular sieve and 5.0 g of pseudo-boehmite were extruded into strips, dried at 120°C for 2 hours, and calcined in air at 550°C for 4 hours to obtain a catalyst support. The binder was added in an amount of 15 wt% of the total catalyst mass. Nickel nitrate was used as a metal precursor, and the catalyst support and metal were compounded by isovolumetric impregnation, with a metal loading of 3.5 wt%. After drying at room temperature, the catalyst was calcined at 400°C for 3 hours. The mass of hydrogen-type molecular sieve in the catalyst was 82.2 wt% of the total catalyst mass.

[0149] Example 5

[0150] 0.80gNaOH and 2.90g HMBr were dissolved in 80g water to form a mother liquor. 4.00g of the ZSM-48 molecular sieve matrix I obtained in Preparation Example 1 was weighed and added to the mother liquor. Aged for 3h under stirring at 30℃, transferred to a 100ml stainless steel reactor, placed in a rotary oven, and hydrothermally crystallized at 160℃ and 60r / min for 96h. After crystallization, it was suddenly cooled to room temperature with cold water, and the sodium-type molecular sieve raw powder V was obtained by filtration, washing and drying. The XRD spectrum of the molecular sieve raw powder V (see Figure 1) confirmed that it was a pure phase ZSM-48 molecular sieve. The product morphology is similar to that of Example 1, and is an ellipsoidal crystal with a cavity structure. The BET surface area of ​​the N2 adsorption and desorption test is 249m 2 / g, with a total pore volume of 0.48 cm 3 The silicon-aluminum ratio (Si / Al2) was 129 as measured by XRF.

[0151] According to the above ratios and synthesis steps, the synthesis can be scaled up in equal proportions.

[0152] The molecular sieve raw powder V was calcined at 550° C. for 4 h in an air atmosphere, and then ion-exchanged with 1 mol / L NH 4 Cl solution at 90° C. for 4 h to obtain the desired hydrogen-type molecular sieve.

[0153] 20.0g of the hydrogen-type molecular sieve and 5.0g of pseudo-boehmite were extruded into strips, dried at 120°C for 2 hours, and calcined at 550°C in air for 4 hours to obtain a catalyst support. The binder was added in an amount of 15wt% based on the total catalyst mass. Nickel nitrate was used as a metal precursor, and the support and metal were compounded by isovolumetric impregnation, achieving a metal loading of 2.5wt%. After drying at room temperature, the support was calcined at 400°C for 3 hours.

[0154] The mass of the hydrogen-type molecular sieve in the catalyst is 83.0 wt% of the total mass of the catalyst.

[0155] Catalytic performance verification:

[0156] The chain alkane isomerization catalysts obtained in Examples 1 to 5 were crushed into 20-40 mesh particles for later use.

[0157] The catalytic performance of the catalyst was evaluated by the hydroisomerization reaction of n-dodecane. The reactant raw material was 99.8 wt% n-dodecane. Before the reaction, the catalyst was activated at 500°C (Examples 1, 3, 4, and 5) or 400°C (Example 2) under a normal pressure hydrogen atmosphere for 3 hours. After the temperature was lowered to the reaction temperature, the pressure was adjusted to 2.0 MPa, and n-dodecane was then introduced into the reaction system using a double plunger pump to initiate the reaction. During the reaction, the volume ratio of hydrogen to n-dodecane was maintained at 10.

[0158] The results are shown in Table 1.

[0159] Table 1 Catalytic performance of catalysts in Examples 1 to 5

[0160] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A chain alkane isomerization catalyst, characterized in that: The chain alkane isomerization catalyst comprises a hydrogen-type ZSM-48 molecular sieve, an active component and a binder; The hydrogen-type ZSM-48 molecular sieve has a spherical crystal structure or an ellipsoidal crystal structure; The hydrogen-type ZSM-48 molecular sieve has micropores and mesopores; The active component is loaded on the hydrogen-type ZSM-48 molecular sieve; The active component includes an active element, and the active element is selected from at least one of nickel, cobalt, platinum and palladium; The binder is selected from at least one of alumina, silica and clay.

2. The chain alkane isomerization catalyst according to claim 1, characterized in that: The mass content of the hydrogen-type ZSM-48 molecular sieve in the chain alkane isomerization catalyst is 40 to 90 wt %; The mass content of the active component in the chain alkane isomerization catalyst is 0.05 to 10 wt %, wherein the mass of the active component is calculated as the mass of the active element; The mass content of the binder in the chain alkane isomerization catalyst is 3 to 15 wt %.

3. The chain alkane isomerization catalyst according to claim 1 or 2, characterized in that: The silicon-aluminum ratio of the hydrogen-type ZSM-48 molecular sieve is 30-400.

4. The chain alkane isomerization catalyst according to any one of claims 1 to 3, characterized in that In the hydrogen-type ZSM-48 molecular sieve, the micropore volume is 0.04 to 0.09 cm 3 / g, mesopore volume is 0.2~0.8cm 3 / g.

5. A method for preparing the chain alkane isomerization catalyst according to any one of claims 1 to 4, characterized in that: The preparation method comprises: (1) After mixing the ZSM-48 molecular sieve matrix with the mother liquor, the mixture is aged I, hydrothermally crystallized I, calcined I, and ion exchanged to obtain the hydrogen-type ZSM-48 molecular sieve; Wherein, the mother solution comprises an aluminum source I, a template agent I, an inorganic base I and water I; (2) Extruding the hydrogen-type ZSM-48 molecular sieve and the binder into strips and calcining them to obtain a carrier; (3) Mixing an aqueous solution containing an active element precursor with the carrier, impregnating with equal volumes, and calcining III to obtain the chain alkane isomerization catalyst.

6. The preparation method according to claim 5, characterized in that: In step (1), the microstructure of the ZSM-48 molecular sieve matrix is ​​spherical or ellipsoidal.

7. The preparation method according to claim 5 or 6, characterized in that: The particle size of the ZSM-48 molecular sieve matrix is ​​400-4000 nm.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The surface of the ZSM-48 molecular sieve matrix has micropores and mesopores, and the pore volume of the micropores is 0.03-0.09 cm 3 / g, total pore volume is 0.02~0.25cm 3 / g.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The silicon-aluminum ratio of the ZSM-48 molecular sieve matrix is ​​≥120.

10. The preparation method according to any one of claims 5 to 9, characterized in that: The preparation method of the ZSM-48 molecular sieve matrix comprises: The aqueous solution containing silicon source II, inorganic base II and template agent II is subjected to aging II and hydrothermal crystallization II to obtain the ZSM-48 molecular sieve matrix.

11. The preparation method according to any one of claims 5 to 10, characterized in that: The silicon source II is selected from at least one of white carbon black, silica sol, ethyl orthosilicate and water glass.

12. The preparation method according to any one of claims 5 to 11, characterized in that: The inorganic base II is selected from at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, lithium hydroxide and ammonia water; The molar ratio of the inorganic base II to the silicon source II is 0.2 to 0.6, wherein the molar amount of the silicon source II is calculated based on the molar amount of SiO2 in the silicon source II, and the molar amount of the inorganic base II is calculated based on the hydroxide in the inorganic base II.

13. The preparation method according to any one of claims 5 to 12, characterized in that: The template II is selected from at least one of hexamethylammonium bromide, hexamethylammonium chloride, and hexamethylammonium hydroxide; The molar ratio of the template II to the silicon source II is 0.02 to 0.3, wherein the molar amount of the template II is calculated based on the molar amount of hexamethylammonium in the template II, and the molar amount of the silicon source II is calculated based on the molar amount of SiO2 in the silicon source II.

14. The preparation method according to any one of claims 5 to 13, characterized in that: The molar ratio of water to the silicon source II in the aqueous solution is 25 to 60, wherein the molar amount of the silicon source II is calculated based on the molar amount of SiO2 in the silicon source II.

15. The preparation method according to any one of claims 5 to 14, characterized in that: The aqueous solution also contains an aluminum source II; the aluminum source II is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudo-boehmite, and aluminum chloride.

16. The preparation method according to any one of claims 5 to 15, characterized in that: The molar ratio of the silicon source II to the aluminum source II is ≥120, wherein the molar amount of the aluminum source II is calculated based on the molar amount of Al2O3 in the aluminum source II; The conditions of the aging II are: temperature of 25-80° C. and time of 2-8 hours.

17. The preparation method according to any one of claims 5 to 16, characterized in that: The conditions of the hydrothermal crystallization II are: dynamic crystallization, temperature of 110-200° C., and time of 48-120 h.

18. The preparation method according to any one of claims 5 to 17, characterized in that: The mass ratio of the mother liquor to the ZSM-48 molecular sieve matrix is ​​5-70.

19. The preparation method according to any one of claims 5 to 18, characterized in that: The aluminum source I is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudo-boehmite or aluminum chloride; In the mother liquor, the concentration of the aluminum source I is 0.001-0.1 mol / L, wherein the concentration of the aluminum source I is measured as the concentration of Al ions.

20. The preparation method according to any one of claims 5 to 19, characterized in that: The inorganic base I is selected from at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide; In the mother liquor, the concentration of the inorganic base I is 0.1 to 0.8 mol / L, wherein the concentration of the inorganic base I is OH - concentration meter.

21. The preparation method according to any one of claims 5 to 20, characterized in that: The template agent I is selected from at least one of hexamethonium bromide, hexamethonium chloride or hexamethonium hydroxide; In the mother solution, the concentration of the template agent I is 0.06-0.45 mol / L, wherein the concentration of the template agent I is measured as the concentration of hexamethylammonium root; The conditions of the aging I are: temperature of 30-80° C. and time of 2-8 h.

22. The preparation method according to any one of claims 5 to 21, characterized in that: The conditions of the hydrothermal crystallization I are: temperature of 120-200° C. and time of 48-200 h.

23. The preparation method according to any one of claims 5 to 22, characterized in that: The conditions of the calcination I are: temperature of 400-600° C. and time of 1-8 hours.

24. The preparation method according to any one of claims 5 to 23, characterized in that: The conditions of the calcination II are: temperature of 300-500° C. and time of 0.5-6 h.

25. The preparation method according to any one of claims 5 to 24, characterized in that: The active element precursor is selected from at least one of nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride, chloroplatinic acid, ammonium chloroplatinate, platinum chloride, and palladium chloride; The conditions for the calcination III are: carried out in an air atmosphere, at a temperature of 300 to 450° C., and for a time of 1 to 3 hours.

26. A method for isomerizing chain alkanes, characterized in that: The method comprises: Under hydrogen I condition, the raw material containing chain alkane is contacted with the pretreated chain alkane isomerization catalyst to react; Wherein, the chain alkane is selected from C6~C 18 At least one of the normal chain alkanes; The chain alkane isomerization catalyst is selected from the chain alkane isomerization catalyst according to any one of claims 1 to 4.

27. The method according to claim 26, characterized in that The pretreatment comprises: performing reduction activation of the chain alkane isomerization catalyst in a hydrogen II atmosphere; The reduction activation temperature is 400-550° C., and the reduction activation time is 1-5 hours.

28. The method according to claim 26 or 27, characterized in that The reaction temperature is 200-370°C; The reaction pressure is 0-4 MPa; The mass space velocity of the hydrogen I is 0.5 to 10 h -1 ; In the reaction, the volume ratio of hydrogen I to chain alkane is 50-400.

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