Hydrocarbon skeletal isomerization catalyst and preparation method and application thereof

Abstract

The invention belongs to the field of catalyst preparation, and relates to a preparation method and application of a novel hydrocarbon isomerization catalyst. The preparation method comprises the following steps: firstly, preparing a metal precursor, wherein the metal precursor can be prepared by loading a metal species in a mesoporous silica channel or interacting the metal species with an anionic polymer; then adding the precursor into an SAPO-11 synthesis system containing a phosphorus source, an aluminum source, a silicon source and a structure-directing agent, and carrying out hydrothermal or dry glue water vapor assisted crystallization; and finally, washing, drying and roasting the crystallized product to obtain the hierarchical porous SAPO-11-based metal catalyst with highly dispersed metal species. The method provided by the invention successfully realizes simultaneous modulation of the dispersity of metal species and the pore structure property of SAPO-11, and effectively improves the activity and isomer selectivity of the catalyst in a hydrocarbon skeletal isomerization reaction; the catalyst can be used for improving the octane number of gasoline, the condensation point of diesel oil, the viscosity-temperature performance of lubricant base oil, the freezing point of biological aviation kerosene and the like.

Description

Technical Field

[0001] The invention belongs to the field of catalyst preparation, and specifically relates to a hydrocarbon skeletal isomerization catalyst and a preparation method and application thereof. Background Art

[0002] In recent years, hydrocarbon skeleton isomerization technology has attracted widespread attention. Using hydrocarbon skeleton isomerization technology to convert normal hydrocarbons into isomeric hydrocarbons is an effective strategy for producing high-octane gasoline, low-freezing point diesel, and lubricant base oils with good low-temperature fluidity. The core of the development of this technology lies in the development of high-performance catalysts.

[0003] Hydrocarbon skeletal isomerization catalysts are usually composed of active metal components with hydrogenation / dehydrogenation functions and acidic molecular sieve carriers with hydrocarbon skeletal isomerization activity. At present, when preparing hydrocarbon skeletal isomerization catalysts, the active metal components are introduced into the molecular sieve carrier by conventional impregnation method, which has defects such as large active metal particle size, uneven dispersion, and large loading, resulting in poor hydrocarbon isomerization performance. In addition, as another important component of hydrocarbon isomerization catalysts, the properties of molecular sieve carriers also have an important influence on the performance of the catalyst. The pore structure in conventional molecular sieves is mainly micropores, and the micropore structure severely restricts the diffusion of isomerized intermediates inside the catalyst, which greatly increases the possibility of cracking side reactions.

[0004] Therefore, how to adjust the metal dispersion of hydrocarbon skeletal isomerization catalysts and the pore structure of molecular sieves and develop hydrocarbon skeletal isomerization catalysts with highly dispersed active metals and rich mesoporous structures has become a focus of attention in the field of hydrocarbon isomerization. Summary of the invention

[0005] The invention provides a method for preparing a hydrocarbon isomerization catalyst, which can prepare a catalyst having high activity and isomer selectivity in hydrocarbon skeleton isomerization reaction.

[0006] The present invention also provides a hydrocarbon isomerization catalyst, which has high activity and isomer selectivity in hydrocarbon skeleton isomerization reaction.

[0007] The invention also provides an isomerization method, which has the characteristics of high activity and isomer selectivity.

[0008] The present invention provides a method for preparing a hydrocarbon isomerization catalyst, which comprises the following steps:

[0009] 1) contacting an active metal source solution with mesoporous silica or anionic polymer to obtain a metal source;

[0010] 2) mixing the metal source with the SAPO-11 synthesis system, and sequentially performing crystallization treatment, drying treatment and calcination treatment on the obtained mixed system to obtain the catalyst;

[0011] The SAPO-11 synthesis system comprises deionized water, a phosphorus source, an aluminum source, a silicon source, and a structure directing agent.

[0012] The preparation method as described above, wherein the process of contacting the active metal source solution with the mesoporous silica specifically includes: dripping the active metal source solution into the mesoporous silica and stirring and mixing, drying at 80-120°C for 6-36h, and calcining at 400-600°C for 0.5-4h to obtain the metal source.

[0013] In the preparation method as described above, the mesoporous silica is at least one of SBA-15, MCM-41 and FDU-12.

[0014] In the preparation method as described above, when the active metal source solution contacts the mesoporous silica to obtain the metal source, the mass ratio of deionized water, aluminum source, phosphorus source, structure directing agent, silicon source and metal source in the mixed system is (20-80):(5-15):(5-20):(5-10):(2-10):(0.5-5).

[0015] In the preparation method as described above, the process of bringing the active metal source solution into contact with the anionic polymer specifically comprises: adding the anionic polymer into the active metal element source solution, stirring and mixing, and obtaining the metal source.

[0016] In the preparation method as described above, the anionic polymer is at least one of polyacrylamide, sodium polyacrylate and polyacrylamide methyl propane sulfonic acid.

[0017] In the preparation method as described above, when the active metal source solution contacts the anionic polymer to obtain the metal source, the mass ratio of deionized water, aluminum source, phosphorus source, structure directing agent, silicon source and metal source in the mixed system is (20-80):(5-15):(5-20):(5-10):(2-10):(5-15).

[0018] The preparation method as described above, wherein the active metal source solution comprises an active metal salt and a solvent, and the active metal salt comprises at least one of nickel nitrate, nickel acetate, nickel chloride, tetraammineplatinum dichloride, and tetraamminepalladium nitrate;

[0019] When the active metal source solution contacts the mesoporous silica, the solvent is selected from any one of ethanol, ethylene glycol and glycerol; the mass ratio of the active metal salt, the mesoporous silica and the solvent is (0.1-3):(1-5):(1-20); the treatment temperature of the stirring and mixing treatment is 50-70°C, and the treatment time is 6-36h;

[0020] When the active metal source solution contacts the anionic polymer, the solvent is deionized water; the mass ratio of the active metal salt, the anionic polymer, and the solvent is (0.1-3):(0.1-0.5):(1-20); the treatment temperature of the stirring and mixing treatment is 20-40° C., and the treatment time is 6-36 hours;

[0021] and / or, the aluminum source comprises at least one of pseudo-boehmite, aluminum isopropoxide, aluminum chloride, aluminum oxide, aluminum sulfate, and aluminum nitrate;

[0022] and / or, the phosphorus source comprises at least one of phosphoric acid, ammonium phosphate and ammonium hydrogen phosphate;

[0023] and / or, the structure directing agent comprises at least one of di-n-propylamine, diisopropylamine and ethylenediamine;

[0024] And / or, the crystallization treatment temperature is 160-200° C. and the time is 18-36 hours;

[0025] And / or, the drying treatment is performed at a temperature of 80-150° C. and for a time of 6-12 h;

[0026] And / or, the calcination treatment is performed at a temperature of 550-700° C. and for a time of 4-8 hours;

[0027] And / or, when the active metal source solution is contacted with mesoporous silica to obtain the metal source, the mixed system is subjected to aging treatment before crystallization treatment, and the treatment temperature of the aging treatment is 10-50° C. and the treatment time is 5-8 hours.

[0028] The present invention also provides a hydrocarbon isomerization catalyst, wherein the hydrocarbon isomerization catalyst is prepared by any of the above-mentioned preparation methods of the hydrocarbon isomerization catalyst.

[0029] The present invention also provides an isomerization method, wherein the above hydrocarbon isomerization catalyst is used to catalytically treat a raw material system including normal hydrocarbon compounds.

[0030] The preparation method of the hydrocarbon isomerization catalyst provided by the invention has the characteristics of being able to prepare a catalyst with high activity and isomer selectivity in hydrocarbon skeleton isomerization reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0032] Figure 1 TEM image of catalyst 40Ni@SA-11-S;

[0033] Figure 2 TEM image of catalyst 40Ni / SA-11-S;

[0034] Figure 3 TEM image of catalyst 40Ni@SA-11-H;

[0035] Figure 4 This is the TEM image of catalyst 40Ni / SA-11-H. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The first aspect of the present invention provides a method for preparing a hydrocarbon isomerization catalyst, the method comprising the following steps:

[0038] 1) contacting an active metal source solution with mesoporous silica or anionic polymer to obtain a metal source;

[0039] 2) mixing the metal source with the SAPO-11 synthesis system, and sequentially performing crystallization treatment, drying treatment and calcination treatment on the obtained mixed system to obtain a catalyst;

[0040] The SAPO-11 synthesis system includes deionized water, a phosphorus source, an aluminum source, a silicon source, and a structure directing agent.

[0041] The preparation method of the hydrocarbon isomerization catalyst provided by the present invention first contacts an active metal source solution with mesoporous silica or anionic polymer to obtain a metal source, and then mixes the metal source with a SAPO-11 synthesis system and undergoes a series of treatments to obtain a hydrocarbon isomerization catalyst.

[0042] Among them, the active metal source solution is a solution including active metal elements. In the preparation method provided by the present invention, the active metal element is selected from at least one of Ni, Pt, and Pd elements. The present invention does not limit the solvent used in the active metal source solution, as long as it meets the requirement of dispersing the above-mentioned active metal elements. In one embodiment, the solvent can be selected from alkanol solvents or deionized water. The present invention also does not limit the mass fraction of the active metal element in the active metal source solution, as long as it meets the requirement of producing a hydrocarbon isomerization catalyst.

[0043] The present invention does not limit the specific selection of mesoporous silica and anionic polymer, the contact time and contact temperature of the active metal source solution and the mesoporous silica or anionic polymer, as long as the requirement of producing a hydrocarbon isomerization catalyst is met.

[0044] In the preparation method provided by the present invention, the SAPO-11 synthesis system includes deionized water, a phosphorus source, an aluminum source, a silicon source, and a structure directing agent. Among them, the aluminum source, the phosphorus source, and the silicon source are substances that can provide aluminum, phosphorus, and silicon, respectively, and the structure directing agent is a substance that can affect the microstructure of the molecular sieve. The present invention does not specifically limit the selection of the aluminum source, the phosphorus source, the silicon source, and the structure directing agent, as long as the requirement of producing a hydrocarbon isomerization catalyst is met. In one embodiment, the aluminum source can be selected from aluminum salts, the phosphorus source can be selected from phosphates, the silicon source can be selected from silica sols or silicon-containing esters, and the structure directing agent can be selected from organic amine structure directing agents.

[0045] The crystallization treatment is a process of heating a mixed system including a metal source and a SAPO-11 synthesis system to convert amorphous substances contained therein into crystals. The present invention does not limit the specific conditions of the crystallization treatment, and the crystallization treatment conditions commonly used in the art can be used. Furthermore, the preparation method provided by the present invention also includes drying and calcining the crystallization product in sequence to obtain a hydrocarbon isomerization catalyst. The present invention also does not limit the specific treatment conditions of the drying treatment and the calcining treatment, and the treatment conditions commonly used in the art can also be used.

[0046] The hydrocarbon isomerization catalyst prepared by the method provided by the present invention is characterized by high activity and isomer selectivity for catalyzing hydrocarbon skeletal isomerization reaction. The inventors believe that the reason may be:

[0047] In the preparation method provided by the present invention, when the active metal source solution is brought into contact with mesoporous silica, the active metal elements in the active metal source act as metal species and are loaded in the pores of the mesoporous silica, and the obtained metal source is an active metal element-silicon dioxide composite; when the active metal source solution is brought into contact with anionic polymer, the active metal elements in the active metal source act as charged metal ions and generate positive and negative electrostatic interactions with the negatively charged anionic polymer, and the obtained metal source is a polymer gel including charged metal ions.

[0048] When the above two metal sources are added to the SAPO-11 synthesis system and mixed to form a mixed system, the active metal elements carried by the metal sources can be evenly distributed in the mixed system, so that in the multi-level porous SAPO-11-based catalyst obtained by crystallization, drying and calcination of the mixed system, the active metal elements are also evenly distributed in the pores.

[0049] Thus, in the catalyst prepared by the preparation method provided by the present invention, the active metal element loading is low and at the same time, it has a higher dispersion, which effectively improves the hydrogenation / dehydrogenation performance of the catalyst; at the same time, the rich mesoporous structure in the synthesized catalyst is conducive to the rapid diffusion of isomeric intermediates inside the catalyst, inhibiting the occurrence of cracking reactions. Therefore, the multi-level porous SAPO-11-based hydrocarbon isomerization catalyst with highly dispersed metal species provided by the present invention exhibits higher reaction activity, can maintain higher selectivity for long-chain isomerized hydrocarbons and lower cracking selectivity.

[0050] Furthermore, the catalyst is applied to hydrocarbon isomerization reaction, and has the function of improving the octane number of gasoline, the pour point of diesel, the viscosity-temperature performance of lubricating oil base oil and the freezing point of aviation kerosene.

[0051] The preparation method provided by the present invention can significantly improve the dispersion of metal species in the prepared catalyst, reduce the required loading amount of metal species, and has the characteristics of being able to prepare a catalyst with high activity and isomer selectivity in hydrocarbon skeleton isomerization reaction.

[0052] In a specific embodiment of the preparation method provided by the present invention, contacting the active metal source solution with the mesoporous silica specifically includes: dripping the active metal source solution into the mesoporous silica and stirring and mixing, drying at 80-120° C. for 6-36 hours, and calcining at 400-600° C. for 0.5-4 hours to obtain the metal source. The above treatment after contacting the active metal source solution with the mesoporous silica helps the active metal source to diffuse more evenly into the mesoporous channels, thereby preparing a hydrocarbon isomerization catalyst with more prominent metal high dispersion characteristics.

[0053] In a specific embodiment, the mesoporous silica is one or a combination of two or more of SBA-15, MCM-41 and FDU-12. Since the above mesoporous silica has the property of confining metal species, the mesoporous channels of the mesoporous silica are used to confine the metal species in the channels, avoiding the aggregation and agglomeration of the metal species during the high temperature treatment process, thereby ensuring the final high dispersion state of the metal species, and thus the catalytic activity and isomer selectivity of the prepared hydrocarbon isomerization catalyst are more prominent.

[0054] Furthermore, when the active metal source solution is contacted with mesoporous silica to obtain the metal source, the mass ratio of deionized water, aluminum source, phosphorus source, structure directing agent, silicon source, and metal source in the mixed system is (20-80):(5-15):(5-20):(5-10):(2-10):(0.5-5). Since the above raw materials have a suitable mass ratio, the prepared hydrocarbon isomerization catalyst has more prominent characteristics of high catalytic activity and isomer selectivity.

[0055] In another embodiment, contacting the active metal source solution with the anionic polymer specifically includes: adding the anionic polymer to the active metal element source solution, stirring and mixing to obtain the metal source. The above treatment helps the active metal element and the anionic polymer to interact electrostatically to obtain a polymer gel of charged metal ions. Further, the anionic polymer is selected from at least one of polyacrylamide, sodium polyacrylate and polyacrylamide methyl propane sulfonic acid. The above anionic polymer, through the principle of isolating metal species, utilizes the electrostatic interaction between the anionic polymer and the positively charged metal species to fully isolate the metal species, thereby avoiding the growth and aggregation of the metal species in subsequent treatment, thereby achieving high dispersion of the metal species, which can make the catalytic activity and isomer selectivity of the prepared hydrocarbon isomerization catalyst more prominent.

[0056] When the carrier is an anionic polymer, in one embodiment, when the active metal source solution is contacted with the anionic polymer to obtain the metal source, the mass ratio of deionized water, aluminum source, phosphorus source, structure directing agent, silicon source, and metal source in the mixed system is (20-80): (5-15): (5-20): (5-10): (2-10): (5-15). Since the above raw materials have a suitable mass ratio, the prepared hydrocarbon isomerization catalyst has more prominent characteristics of high catalytic activity and isomer selectivity.

[0057] In one embodiment, the active metal source solution includes an active metal salt and a solvent, and the active metal salt includes at least one of nickel nitrate, nickel acetate, nickel chloride, tetraammine platinum dichloride, and tetraammine palladium nitrate. The above substances are easily dispersed in deionized water or alkanol solvents, which helps to evenly distribute the active metal elements in the metal source.

[0058] Furthermore, when the active metal source solution contacts the mesoporous silica, the solvent is selected from any one of ethanol, ethylene glycol and glycerol; the mass ratio of active metal salt, mesoporous silica and solvent is (0.1-3): (1-5): (1-20); the treatment temperature of the stirring and mixing treatment is 50-70°C, and the treatment time is 6-36h. Since the metal source solution includes an alkane solvent, the alkane solvent has a guided diffusion function, which helps the active metal source to diffuse more evenly into the mesoporous pores, thereby obtaining a hydrocarbon isomerization catalyst with more prominent metal high dispersion characteristics; when the active metal source solution contacts the anionic polymer, the solvent is deionized water; the mass ratio of active metal salt, anionic polymer and solvent is (0.1-3): (0.1-0.5): (1-20); the treatment temperature of the stirring and mixing treatment is 20-40°C, and the treatment time is 6-36h. Selecting different solvents and contact conditions according to different substances in contact with the active metal source solution helps to achieve further uniform distribution of active metal elements in the metal source.

[0059] Furthermore, the aluminum source includes at least one of pseudo-boehmite, aluminum isopropoxide, aluminum trichloride, aluminum oxide, aluminum sulfate and aluminum nitrate; the phosphorus source includes at least one of phosphoric acid, ammonium phosphate and ammonium hydrogen phosphate; and the structure directing agent includes at least one of di-n-propylamine, diisopropylamine and ethylenediamine. Since the above substances can be transformed from amorphous to crystalline, the hydrocarbon skeleton isomerization performance of the prepared catalyst is more prominent.

[0060] Furthermore, by controlling the crystallization temperature to 160-200°C and the time to 18-36h, the drying temperature to 80-150°C and the time to 6-12h, and the calcination temperature to 550-700°C and the time to 4-8h, the heat treatment principle can be used to make the catalytic activity and isomer selectivity of the prepared hydrocarbon isomerization catalyst more prominent.

[0061] In one embodiment, when the active metal source solution is contacted with the mesoporous silica to obtain the metal source, the mixed system is also subjected to an aging treatment before the crystallization treatment, and the aging treatment temperature is 10-50° C. and the treatment time is 5-8 hours. The aging treatment can make each substance fully react, thereby making the catalytic activity and isomer selectivity of the prepared hydrocarbon isomerization catalyst more prominent.

[0062] The second aspect of the present invention provides a hydrocarbon isomerization catalyst, which is prepared by the preparation method of any hydrocarbon isomerization catalyst provided by the first aspect of the present invention. The hydrocarbon isomerization catalyst provided by the present invention has a specific surface area of ​​190 m 2 / g, mesopore volume is greater than or equal to 0.25cm 3 / g, total pore volume greater than or equal to 0.28cm 3 / g, the mass fraction of active metal in the catalyst is 0.2-5.0wt%. Further, when the active metal element in the hydrocarbon isomerization catalyst is nickel, the catalyst contains NiO particles, and the particle size is less than or equal to 6nm.

[0063] The hydrocarbon isomerization catalyst provided by the present invention has a high dispersion of metal species and a low metal species loading, and has a high hydrogenation / dehydrogenation performance; at the same time, the rich mesoporous structure in the synthesized catalyst is conducive to the rapid diffusion of isomerized intermediates inside the catalyst, inhibiting the occurrence of cracking reactions. Furthermore, the hydrocarbon isomerization catalyst provided by the present invention exhibits a high reaction activity, can maintain a high selectivity for long-chain isomerized hydrocarbons and a low cracking selectivity. The catalyst is applied to hydrocarbon isomerization reactions, and can be used to improve the octane number of gasoline, the pour point of diesel, the viscosity-temperature performance of lubricating oil base oil, the freezing point of aviation kerosene, and other aspects.

[0064] The hydrocarbon isomerization catalyst provided by the present invention has the advantages of high activity and isomer selectivity in hydrocarbon skeletal isomerization reaction.

[0065] The third aspect of the present invention provides an isomerization method, which comprises using the hydrocarbon isomerization catalyst provided by the second aspect of the present invention to catalytically treat a raw material system including normal hydrocarbon compounds. The present invention does not limit the specific treatment conditions of the catalytic treatment, and it is sufficient to meet the requirement of converting normal hydrocarbon compounds in the raw material system into isomerized hydrocarbon compounds.

[0066] In one embodiment, the catalytic treatment adopts the following conditions: the hydrocarbon isomerization catalyst powder is pressed into tablets at 15MPa, ground and sieved into particles of 20 to 40 mesh for standby use; 1.0g of the above-mentioned formed catalyst particles are weighed, and are evenly mixed with an equal volume of quartz sand and then loaded into a reaction tube; 50mL / min of hydrogen atmosphere is introduced into the reaction forward device, and the catalyst is reduced at 500°C and 2.0MPa for 2h; after the temperature of the reaction device drops to 380°C, the raw material system including normal hydrocarbon compounds is pumped into the reactor, and the hydrogen-to-hydrocarbon volume ratio, the reaction pressure, and the liquid mass space velocity are controlled to be 400, 2.0MPa, and 5h -1 After the temperature of the reaction device drops to 380°C, the raw material system including normal hydrocarbon compounds is pumped into the reactor, and the hydrogen-to-hydrocarbon volume ratio is controlled to be 400.

[0067] The isomerization method provided by the invention has the characteristics of high activity and isomer selectivity.

[0068] The solution provided by the present invention is further described below in conjunction with specific embodiments.

[0069] Example 1

[0070] 1) First, prepare the precursor. The detailed steps are described as follows: 166 parts of Ni(NO3)2·6H2O are dissolved in 1200 parts of ethylene glycol, and then the above solution is dropped into 300 parts of mesoporous silica SBA-15, stirred at 60°C for 8h, vacuum dried at 80°C for 12h and calcined at 550°C in a nitrogen atmosphere for 4h to obtain a Ni@SBA-15 precursor.

[0071] 2) Introducing the above precursor into the SAPO-11 synthesis system, the detailed steps are described as follows: by mass, 810 parts of pseudo-boehmite are added to 4000 parts of deionized water, and stirred at a constant temperature of 35°C for 1 hour; 1220 parts of phosphoric acid and 680 parts of di-n-propylamine are added to the above solution, and stirred at a constant temperature of 35°C for 2 hours; 230 parts of tetraethyl silicate are added to the above solution, and stirred at a constant temperature of 35°C for 2 hours; 270 parts of Ni@SBA-15 precursor are added to the above system, and stirred at a constant temperature of 35°C for 1 hour to obtain a uniform gel.

[0072] 3) The gel was transferred to a 100 mL reactor and crystallized at 200°C for 24 h. After the reactor was cooled to 25°C, the crystallized product was centrifuged, washed, dried, and calcined at 600°C in air atmosphere for 6 h to obtain a hydrogenation isomerization catalyst Ni@SAPO-11, named 40Ni@SA-11-S.

[0073] The Ni loading in the catalyst was measured by ICP method and was 3.9 wt%.

[0074] Example 2

[0075] 1) First, a precursor was prepared. The detailed steps are as follows: 140 parts by mass of Ni(CH3COO)2·4H2O were dissolved in 1000 parts of deionized water, and 30 parts of polyacrylamide were added and stirred for 12 hours to obtain solution A.

[0076] 2) Introducing the above precursor into the SAPO-11 synthesis system, the detailed steps are described as follows: by mass, 810 parts of pseudo-boehmite are added to 4000 parts of deionized water, and stirred at a constant temperature of 35°C for 1 hour; 1220 parts of phosphoric acid and 680 parts of di-n-propylamine are added to the above solution, and stirred at a constant temperature of 35°C for 2 hours; then 470 parts of tetraethyl silicate are added to the above solution, and stirred at a constant temperature of 35°C for 2 hours to obtain solution B; solution A is mixed with solution B, and stirred at a constant temperature of 35°C for 1 hour to obtain a uniform gel; the above gel is evaporated to dryness at 80°C and ground into fine powder for use.

[0077] 3) Weigh 200 parts of the above-mentioned dry rubber powder by mass and place them in the middle of a 100 mL crystallization kettle, and then add 1000 parts of deionized water to the bottom to avoid direct contact between the dry rubber and the water at the bottom of the kettle; heat the above-mentioned reactor to 200°C and crystallize at a constant temperature for 24 hours; after the reactor is cooled to 25°C, the crystallized product is centrifuged, washed and dried, and calcined at 600°C in air atmosphere for 6 hours to obtain a hydrogenation isomerization catalyst Ni@SAPO-11, named: 40Ni@SA-11-H.

[0078] The Ni loading in the catalyst was measured by ICP method and was 4.0 wt%.

[0079] Comparative Example 1

[0080] This comparative example is basically the same as Example 1, except that in step 2), the Ni@SBA-15 precursor is replaced with an equal mass of tetraethyl silicate, and step 3) is performed to obtain a SAPO-11 carrier; subsequently, Ni(NO3)2·6H2O is used as a metal source, 4.0 wt% Ni is loaded on the above-mentioned SAPO-11 carrier by an equal volume impregnation method, and the mixture is dried at 120°C for 12 h and calcined at 500°C in an air atmosphere for 4 h to obtain a hydroisomerization catalyst Ni / SAPO-11, named: 40Ni / SA-11-S.

[0081] The Ni loading in the catalyst was measured by ICP method and was 4.0 wt%.

[0082] Comparative Example 2

[0083] This comparative example is basically the same as Example 2, except that, in step 2), solution A is not added, and step 3) is performed to obtain a SAPO-11 carrier; then Ni(CH3COO)2·4H2O is used as a metal source, and 4.0 wt.% Ni is loaded on the above SAPO-11 carrier by an equal volume impregnation method to obtain a hydroisomerization catalyst Ni / SAPO-11, named: 40Ni / SA-11-H.

[0084] The Ni loading in the catalyst was measured by ICP method and was 3.9 wt%.

[0085] Test example

[0086] 1. Catalytic performance test

[0087] The catalyst powders prepared in the embodiments and comparative examples were tableted at 15 MPa, ground and sieved into particles of 20 to 40 mesh for later use; 1.0 g of the above-mentioned formed catalyst particles were weighed, mixed evenly with an equal volume of quartz sand and then loaded into a reaction tube; 50 mL / min of hydrogen atmosphere was introduced into the reaction forward device, and the catalyst was reduced at 500° C. and 2.0 MPa for 2 h; after the temperature of the reaction device dropped to 380° C., n-decane was pumped into the reactor, and the hydrogen-to-hydrocarbon volume ratio, the reaction pressure, and the liquid mass space velocity were controlled to be 400, 2.0 MPa, and 5 h -1 After the temperature of the reaction device dropped to 380°C, n-decane was pumped into the reactor, and the hydrogen-to-hydrocarbon volume ratio was controlled to be 400. The raw material conversion rate, total isomer selectivity, cracking product selectivity, and total isomer yield were statistically analyzed after 72 hours of reaction. The data are shown in Table 1.

[0088] n-Decane (nC 10 ) conversion rate (X), total isomer selectivity (S i ), total isomer yield (Y i ) and cracking selectivity (S c ) is calculated as follows:

[0089]

[0090] Among them, C f and C p nC before and after isomerization reaction 10 The concentration of C i and C c nC respectively 10 The concentration of isodecane in the isomerization product and the concentration of cracking products.

[0091] Table 1 Catalytic performance test data

[0092]

[0093] It can be seen from Table 1 that compared with the catalysts prepared in Comparative Examples 1 and 2, the catalysts 40Ni@SA-11-S and 40Ni@SA-11-H prepared in Examples 1 and 2 have higher feedstock conversion rate, total isomer selectivity, and total isomer yield, while also having lower cracking product selectivity.

[0094] 2. Catalyst morphology test

[0095] The BET specific surface area, mesopore volume and total pore volume of the catalysts prepared in each embodiment and comparative example were measured. The data are shown in Table 2.

[0096] Table 2

[0097] catalyst <![CDATA[SBET(m 2 / g)]]> <![CDATA[V mesopore (cm 3 / g)]]> <![CDATA[Total volume (cm 3 / g)]]> 40Ni@SA-11-S 271 0.35 0.39 40Ni@SA-11-H 194 0.25 0.28 40Ni / SA-11-S 139 0.09 0.11 40Ni / SA-11-H 153 0.10 0.12

[0098] It can be seen from Table 2 that compared with the catalysts prepared in Comparative Examples 1 and 2, the catalysts 40Ni@SA-11-S and 40Ni@SA-11-H prepared in Examples 1 and 2 have higher BET specific surface area, mesopore volume and total pore volume.

[0099] 3. Observation of morphological features

[0100] TEM observation of catalyst 40Ni@SA-11-S revealed Figure 1 ;

[0101] TEM observation of catalyst 40Ni / SA-11-S revealed Figure 2 ;

[0102] TEM observation of catalyst 40Ni@SA-11-H revealed Figure 3 ;

[0103] TEM observation of catalyst 40Ni / SA-11-H revealed Figure 4 .

[0104] contrast Figure 1-Figure 4 It can be seen that compared with the 40Ni / SA-11-S catalyst (NiO particle size is about 20nm), the NiO particle size in the 40Ni@SA-11-S catalyst is smaller (about 5.1nm), indicating a higher dispersion of metal species in the catalyst. Figure 1-Figure 4 Marked with a red circle.

[0105] Furthermore, compared with the 40Ni / SA-11-H catalyst (Ni particle size is about 20 nm), the NiO particle size in the 40Ni@SA-11-H catalyst is smaller (about 1.4 nm), indicating that the dispersion effect of metal species in this catalyst is better.

[0106] From Table 2, Figure 1-Figure 4 It can be seen that the catalyst provided by the present invention has excellent selectivity for long-chain hydrocarbon isomers and low selectivity for cracking products. This is because: on the one hand, the 40Ni@S-11-S and 40Ni@S-11-H catalysts synthesized by the method of the present invention have rich mesoporous structures (see Table 2), which reduce the diffusion resistance of isomerized intermediates and reduce the possibility of cracking reactions; on the other hand, the Ni precursor introduced in situ in the molecular sieve synthesis system forms highly dispersed active Ni species in the catalyst after treatment (see Table 2). Figure 1 , Figure 3 ), which can effectively improve the accessibility between the metal active sites and the acidic sites of the molecular sieve, so that the isomeric intermediates generated at the acidic sites can quickly migrate to the metal active sites to complete hydrogenation, thereby improving the selectivity of its long-chain hydrocarbon isomers.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a hydrocarbon isomerization catalyst, characterized in that: The following steps are involved: 1) contacting an active metal source solution with mesoporous silica or anionic polymer to obtain a metal source; 2) mixing the metal source with the SAPO-11 synthesis system, and sequentially performing crystallization treatment, drying treatment and calcination treatment on the obtained mixed system to obtain the catalyst; The SAPO-11 synthesis system comprises deionized water, a phosphorus source, an aluminum source, a silicon source, and a structure directing agent.

2. The preparation method according to claim 1, characterized in that: The process of contacting the active metal source solution with the mesoporous silica specifically includes: dropping the active metal source solution into the mesoporous silica and stirring and mixing, drying at 80-120° C. for 6-36 hours, and calcining at 400-600° C. for 0.5-4 hours to obtain the metal source.

3. The preparation method according to claim 1 or 2, characterized in that: The mesoporous silica is at least one of SBA-15, MCM-41 and FDU-12.

4. The preparation method according to any one of claims 1 to 3, characterized in that When the active metal source solution contacts mesoporous silica to obtain the metal source, the mass ratio of deionized water, aluminum source, phosphorus source, structure directing agent, silicon source and metal source in the mixed system is (20-80):(5-15):(5-20):(5-10):(2-10):(0.5-5).

5. The preparation method according to claim 1, characterized in that: The process of bringing the active metal source solution into contact with the anionic polymer specifically includes: adding the anionic polymer into the active metal element source solution, stirring and mixing, and obtaining the metal source.

6. The preparation method according to claim 5, characterized in that: The anionic polymer is at least one of polyacrylamide, sodium polyacrylate and polyacrylamide methyl propane sulfonic acid.

7. The preparation method according to claim 5 or 6, characterized in that: When the active metal source solution contacts the anionic polymer to obtain the metal source, the mass ratio of deionized water, aluminum source, phosphorus source, structure directing agent, silicon source and metal source in the mixed system is (20-80):(5-15):(5-20):(5-10):(2-10):(5-15).

8. The preparation method according to claim 2 or 5, characterized in that: The active metal source solution comprises an active metal salt and a solvent, wherein the active metal salt comprises at least one of nickel nitrate, nickel acetate, nickel chloride, tetraammine platinum dichloride, and tetraammine palladium nitrate; When the active metal source solution contacts the mesoporous silica, the solvent is selected from any one of ethanol, ethylene glycol and glycerol; the mass ratio of the active metal salt, the mesoporous silica and the solvent is (0.1-3):(1-5):(1-20); the treatment temperature of the stirring and mixing treatment is 50-70°C, and the treatment time is 6-36h; When the active metal source solution contacts the anionic polymer, the solvent is deionized water; the mass ratio of the active metal salt, the anionic polymer, and the solvent is (0.1-3):(0.1-0.5):(1-20); the treatment temperature of the stirring and mixing treatment is 20-40° C., and the treatment time is 6-36 hours; and / or, the aluminum source comprises at least one of pseudo-boehmite, aluminum isopropoxide, aluminum chloride, aluminum oxide, aluminum sulfate, and aluminum nitrate; and / or, the phosphorus source comprises at least one of phosphoric acid, ammonium phosphate and ammonium hydrogen phosphate; and / or, the structure directing agent comprises at least one of di-n-propylamine, diisopropylamine and ethylenediamine; And / or, the crystallization treatment temperature is 160-200° C. and the time is 18-36 hours; And / or, the drying treatment is performed at a temperature of 80-150° C. and for a time of 6-12 h; And / or, the calcination treatment is performed at a temperature of 550-700° C. and for a time of 4-8 hours; And / or, when the active metal source solution is contacted with mesoporous silica to obtain the metal source, the mixed system is subjected to aging treatment before crystallization treatment, and the treatment temperature of the aging treatment is 10-50° C. and the treatment time is 5-8 hours.

9. A hydrocarbon isomerization catalyst, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 8.

10. An isomerization method, characterized in that: The hydrocarbon isomerization catalyst according to claim 9 is used to catalytically treat a raw material system including normal hydrocarbon compounds.

Images