Hydroisomerization catalyst, process for its preparation and use

Abstract

The application discloses a kind of hydrogenation isomerization catalyst and its preparation method and application, belong to biological aviation kerosene preparation technical field.The hydrogenation isomerization catalyst includes composite carrier and catalytic active component supported on composite carrier;The composite carrier is the SAPO-11 / ZSM-5 composite molecular sieve modified with La2O3 and P;The composite carrier has mesoporous-microporous multistage pore structure, wherein the pore size of mesoporous is 10-30nm, the pore size of microporous is 0.5-0.6nm, total pore volume is greater than or equal to 0.8cm 3 / g;The catalytic active component is the combination of Pt, Ir, Pd.The application is applied to the preparation of biological aviation kerosene, realizes that cracking rate is reduced to 8-10%, C10-C16 isomerized alkanes yield is improved to 75-80%, isomerization selectivity reaches 88-92%, 1000h activity drop≤5%, the catalyst can efficiently catalyze directional conversion of raw materials such as animal and vegetable oils into the C10-C16 isomerized alkanes required for biological aviation kerosene, improve biological aviation kerosene index, while subsequent rectification extraction of C10-C16 isomerized component can obtain higher value-added products, suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bio aviation kerosene preparation, and particularly relates to a hydrogenation isomerization catalyst and a preparation method and application thereof. BACKGROUND

[0002] Under the background of increasingly tight supply of traditional fossil energy and continuously increasing pressure of carbon dioxide emission reduction, developing renewable and clean alternative energy has become a global common understanding. Bioenergy has attracted much attention in recent years due to its renewability and greenness, and is regarded as one of the ideal ways to solve the global energy crisis. With the continuous rise in demand for biofuels, the technology of preparing bio aviation kerosene from renewable raw materials has attracted more and more attention. Isomeric alkanes with a carbon chain length in the range of C10-C16 are key components of bio aviation kerosene, and improving their yield is crucial to the quality of bio aviation kerosene.

[0003] In the existing literature (Research on preparation of bio aviation kerosene by one-step catalytic hydrogenation of jatropha oil. Yunnan Normal University, 2017.), Hao Yajie et al. used jatropha oil as raw oil and Pt / SAPO-11 catalyst as the catalyst used in the experiment to explore the optimal reaction conditions for preparing bio aviation kerosene by fixed-bed catalytic hydrogenation through single-factor experiments. Under the conditions of a reaction temperature of 400℃, a reaction pressure of 5 MPa, a hydrogen to oil ratio of 1000 and a space velocity of 1.2 h-1, the deoxygenation rate of the product was 98.13%, the C8-C16 ratio was 45.38%, and the C8-C16 isomerization rate was 32.49%. However, the method in this literature uses a single Pt metal catalyst, resulting in a low yield of C8-C16 isomeric alkanes, which is not conducive to the extraction of subsequent high-value-added products. SUMMARY

[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present application is the low yield of C10-C16 isomeric alkanes of traditional bio aviation kerosene hydrogenation isomerization catalysts. The present application proposes a hydrogenation isomerization catalyst and a preparation method and application thereof by using a Pt-Ir-Pd three-metal system, optimizing the carrier structure and synergistically regulating the additives, thereby weakening the cracking performance and improving the yield of C10-C16 isomeric alkanes.

[0005] To solve the technical problem, the technical solution adopted by the present application is as follows:

[0006] In one aspect, the present application provides a hydrogenation isomerization catalyst, which comprises a composite carrier and a catalytically active component loaded on the composite carrier.

[0007] The composite carrier is a SAPO-11 / ZSM-5 composite molecular sieve modified by La2O3 and P.

[0008] The composite carrier has a mesopore-micropore multi-level pore structure, wherein the pore size of the mesopore is 10-30 nm, the pore size of the micropore is 0.5-0.6 nm, and the total pore volume is greater than or equal to 0.8 cm 3 / g.

[0009] The catalytically active component is a combination of Pt, Ir and Pd.

[0010] The content of the catalytically active component is calculated based on the metal element, and the content of Pt is 0.5-1.0 wt% of the total mass of the hydrogen isomerization catalyst, the content of Ir is 0.2-0.5 wt% of the total mass of the hydrogen isomerization catalyst, and the content of Pd is 0.1-0.3 wt% of the total mass of the hydrogen isomerization catalyst.

[0011] Preferably, the composite carrier is prepared by the following method:

[0012] The SAPO-11 molecular sieve and the ZSM-5 molecular sieve are mixed in a mass ratio of (7-8):(2-3) to obtain a SAPO-11 / ZSM-5 composite molecular sieve.

[0013] The La2O3 precursor and the P precursor are dissolved in water to obtain a mixed solution.

[0014] The SAPO-11 / ZSM-5 composite molecular sieve is added to the mixed solution, stirred at 25-100°C, and after the solvent is removed by drying, calcination is performed at 500-600°C for 3-5 hours to obtain the composite carrier.

[0015] Preferably, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 50-100.

[0016] Preferably, the content of the La2O3 precursor is 1-2% of the mass of the SAPO-11 / ZSM-5 composite molecular sieve, and the content of the P precursor is 0.5-1% of the mass of the SAPO-11 / ZSM-5 composite molecular sieve.

[0017] The addition amount of the SAPO-11 / ZSM-5 composite molecular sieve and the mixed solution is in a ratio of 1g:1-10mL.

[0018] Another aspect of the present application provides a preparation method of the above-mentioned hydrogen isomerization catalyst, which comprises a catalytically active component loading step and a pore structure optimization step.

[0019] The catalytically active component loading step comprises:

[0020] The Pt metal salt, the Ir metal salt and the Pd metal salt are mixed with the composite carrier and then dissolved in a solvent, stirred uniformly, dried and calcined to obtain a primary product.

[0021] The pore structure optimization step comprises:

[0022] The primary product is added into a tetrapropyl ammonium bromide aqueous solution, and reacted at 100-250 DEG C for 5-100 hours, and after filtration and drying, reduction treatment is performed to obtain a hydrogenation isomerization catalyst.

[0023] Preferably, in the catalyst active component loading step, the solvent is water or ethanol; the calcination temperature is 400-600 DEG C, and the time is 2-4 hours.

[0024] Preferably, in the pore structure optimization step, the mass fraction of the tetrapropyl ammonium bromide aqueous solution is 10-60%, the ratio of the addition amount of the primary product to the tetrapropyl ammonium bromide aqueous solution is 1g:10-50mL; and the reduction treatment conditions are: reduction in a hydrogen atmosphere at 300-500 DEG C for 2-4 hours, and the hydrogen flow rate is 20-50mL / min.

[0025] Another aspect of the present application provides application of the hydrogenation isomerization catalyst in catalytic preparation of bio-jet fuel.

[0026] Another aspect of the present application provides application of the hydrogenation isomerization catalyst in improving the C10-C16 isomeric alkane yield in bio-jet fuel.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The present application provides a hydrogenation isomerization catalyst, which takes SAPO-11 / ZSM-5 as a composite carrier, has a mesopore-micropore multi-level pore structure, loads a Pt-Ir-Pd metal combination, and introduces La2O3 and P as a composite additive, weakens cracking activity through metal synergy, adapts C10-C16 isomerization through carrier acidity and pore structure, and controls stability through an additive, so that the cracking rate (<C10 product) is reduced to 8-10%, the C10-C16 isomeric alkane yield is improved to 75-80%, the isomerization selectivity is 88-92%, and the activity reduction is ≤5% in 1000h, the catalyst can efficiently catalyze directional conversion of raw materials such as animal and vegetable oils into C10-C16 isomeric alkanes required by bio-jet fuel, improves bio-jet fuel indexes, and can subsequently perform rectification extraction of C10-C16 isomeric components to obtain higher value-added products, and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure is a morphology test figure of the hydrogenation isomerization catalyst provided in Example 1 of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only part of the specific implementation manners of the overall technical solutions of the present application, but not all the implementation manners. Based on the overall concept of the present application, all other embodiments obtained by those skilled in the art fall within the scope of protection of the present application.

[0031] The present application provides a hydroisomerization catalyst in one aspect, the hydroisomerization catalyst comprising a composite carrier and a catalytically active component supported on the composite carrier.

[0032] The composite carrier is a SAPO-11 / ZSM-5 composite molecular sieve modified with La2O3 and P.

[0033] The composite carrier has a mesopore-micropore multi-level pore structure, wherein the pore size of the mesopore is 10-30 nm, the pore size of the micropore is 0.5-0.6 nm, and the total pore volume is ≥0.8 cm 3 / g.

[0034] The catalytically active component is a combination of Pt, Ir, and Pd.

[0035] It should be noted that isomeric alkanes with a carbon chain length in the range of C10-C16 are key components of bio-jet fuel, and improving their yield is crucial to the quality of bio-jet fuel. However, the commonly used bio-jet fuel hydroisomerization catalysts still have obvious defects: first, the metal system has defects, usually using Ni, Mo and other metals (single component or simple mixture), which has strong cracking activity, leading to excessive cracking of long-chain alkanes, generating a large amount of <C10 small molecules, and low retention rate of C10-C16 precursors. Second, the carrier performance is insufficient, and traditional catalysts mostly use single molecular sieves, such as single ZSM-5 molecular sieves, which have many strong acid sites, which easily leads to excessive cracking reaction, and the pore structure of the carrier of the traditional catalyst is not optimized for the characteristics of C10-C16 molecules, and the diffusion limitation is obvious. Finally, the existing bio-jet fuel hydroisomerization catalysts have no acid regulation additives, which cannot effectively weaken the strong acid sites and stabilize the metal dispersion, leading to fast coke deposition and poor stability of the catalyst, affecting the continuous generation of C10-C16 isomeric alkanes. In summary, the traditional bio-jet fuel hydroisomerization catalysts are difficult to balance the synergy of cracking and isomerization, resulting in a C10-C16 isomeric alkane yield of only 60%-65%, which is not conducive to the extraction of subsequent high-value-added products.

[0036] To solve the above problems, the application limits the selection of La2O3 and P as acidic control additives, because La2O3 neutralizes part of the strong acid sites, reducing C-C bond breaking; P enhances the interaction between the carrier and the metal, avoiding Pt-Ir agglomeration, improving metal dispersion, and the synergistic effect of the additives can reduce the probability of catalyst carbon deposition, thereby improving the service life of the catalyst and ensuring long-term stable production of C10-C16 isomeric alkanes. The above technical solution also limits the selection of SAPO-11 / ZSM-5 composite molecular sieve, because SAPO-11 molecular sieve provides weak-moderate acid sites and elliptical ten-membered ring pores (0.39x0.63nm), which have shape-selective isomerization effect on C10-C16 long-chain alkanes; ZSM-5 retains moderate cracking activity (only breaking C17+ to C10-C16), and cooperates with the mesoporous-microporous multi-level pore structure, mesopores (10-30nm) promote the diffusion of C10-C16 molecules, micropores (0.5-0.6nm) limit excessive cracking, and the total pore volume is ≥0.8cm 3 / g, which not only limits excessive cracking, but also promotes the diffusion of C10-C16 molecules, significantly improving the isomerization efficiency; in addition, the application uses a Pt-Ir-Pd three-metal system instead of the traditional metal system mainly composed of Ni and Mo, in which Pt-Ir weakens the ability to dissociate C-C bonds through electronic complementation (the 5d 7 electronic configuration of Ir reduces the binding energy of C-C bonds by about 8kJ / mol compared to Ni), reducing the cracking of long-chain alkanes; Pd inhibits carbon deposition to ensure diffusion, reduces the cracking rate, and improves the yield of C10-C16.

[0037] In a preferred embodiment, the content of the catalytically active component is calculated based on the metal element, and Pt accounts for 0.5-1.0wt% of the total mass of the hydroisomerization catalyst, Ir accounts for 0.2-0.5wt% of the total mass of the hydroisomerization catalyst, and Pd accounts for 0.1-0.3wt% of the total mass of the hydroisomerization catalyst.

[0038] The above technical solution limits the content of Pt, Ir and Pd, wherein Pt serves as the main active center and retains high hydroisomerization activity; Ir and Pd form an electronic synergy, and the 5d 7 electronic configuration of Ir reduces the binding energy of C-C bonds by about 8kJ / mol compared to Ni), reducing the cracking; a small amount of Pd inhibits the polymerization of olefins and carbon deposition, and improves the diffusion of products.

[0039] In a preferred embodiment, the composite carrier is prepared by the following method:

[0040] The SAPO-11 molecular sieve and the ZSM-5 molecular sieve are mixed in a mass ratio of (7-8):(2-3) to obtain a SAPO-11 / ZSM-5 composite molecular sieve;

[0041] The La2O3 precursor and the P precursor are dissolved in water to obtain a mixed solution;

[0042] The SAPO-11 / ZSM-5 composite molecular sieve is added into the mixed solution, stirred at 25-100℃, dried to remove the solvent, and then calcined at 500-600℃ for 3-5 hours to obtain the composite carrier.

[0043] In the preparation steps of the composite carrier, the mass ratio of the SAPO-11 molecular sieve to the ZSM-5 molecular sieve is (7-8):(2-3), because this ratio can balance the isomerization and moderate cracking activity: if the SAPO-11 accounts for too high a proportion, C17+ long-chain alkanes cannot be effectively broken into C10-C16, and if the SAPO-11 accounts for too low a proportion, excessive cracking is intensified; in addition, in the above preparation steps, the stirring temperature is controlled at 25-100℃ to ensure that the precursors are uniformly dispersed on the surface of the molecular sieve, avoiding uneven distribution of acid sites caused by local aggregation.

[0044] In a preferred embodiment, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 50-100.

[0045] The above technical solution limits the silicon-aluminum ratio of the ZSM-5 molecular sieve to 50-100, because high-silicon-aluminum-ratio ZSM-5 (Si / Al=50-100) retains moderate cracking activity (only C17+ is broken), which can avoid excessive breaking of C10-C16 carbon chains, and if the silicon-aluminum ratio is lower than 50, the <C10 product will increase.

[0046] In a preferred embodiment, the La2O3 precursor accounts for 1-2% of the mass of the SAPO-11 / ZSM-5 composite molecular sieve, and the P precursor accounts for 0.5-1% of the mass of the SAPO-11 / ZSM-5 composite molecular sieve.

[0047] The SAPO-11 / ZSM-5 composite molecular sieve and the mixed solution are added in a ratio of 1g:1-10mL.

[0048] In a preferred embodiment, the La2O3 precursor is one or more of lanthanum nitrate, lanthanum chloride, and lanthanum acetate; and the P precursor is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and ammonium phosphate.

[0049] Another aspect of the present application provides a preparation method of the above hydrogen isomerization catalyst, which comprises a catalyst active component loading step.

[0050] The catalyst active component loading step comprises:

[0051] The Pt metal salt, the Ir metal salt, and the Pd metal salt are mixed with the composite carrier, dissolved in a solvent, stirred uniformly, dried, and then calcined to obtain a primary product.

[0052] In a preferred embodiment, the Pt metal salt can be one or more of H2PtCl6, Pt(NO3)2 and Pt(NH3)4Cl2; the Ir metal salt can be one or more of IrCl3, Ir(NO3)3 and H2IrCl6; and the Pd metal salt can be one or more of PdCl2, Pd(NO3)2 and Pd(NH3)4Cl2.

[0053] In a preferred embodiment, in the step of loading the catalytically active component, the solvent is water or ethanol; the stirring temperature is 25-100°C; and the calcination temperature is 400-600°C for 2-4 hours.

[0054] In a preferred embodiment, the method for preparing the hydroisomerization catalyst further comprises a pore structure optimization step.

[0055] The pore structure optimization step comprises:

[0056] The primary product is added to an aqueous solution of tetrapropylammonium bromide, and reacted at 100-250°C for 5-100 hours. After filtration and drying, reduction treatment is performed to obtain the hydroisomerization catalyst.

[0057] In a preferred embodiment, in the pore structure optimization step, the mass fraction of the aqueous solution of tetrapropylammonium bromide is 10%-60%, and the ratio of the amount of the primary product to the aqueous solution of tetrapropylammonium bromide is 1g:10-50mL. The reduction treatment conditions are: reduction at 300-500°C for 2-4 hours in a hydrogen atmosphere, and the hydrogen flow rate is 20-50mL / min.

[0058] In the pore structure optimization step, the aqueous solution of tetrapropylammonium bromide is used as a mesopore template agent, and the concentration and liquid-solid ratio thereof can control the mesopore size and distribution, so as to ensure that the mesopore size is stable at 10-30nm. The reduction treatment can completely convert the metal oxides into metal elements with catalytic activity, and the hydrogen flow rate and temperature can avoid sintering of the metal particles.

[0059] Another aspect of the present application provides the use of the hydroisomerization catalyst in the catalytic preparation of bio-jet fuel.

[0060] In a preferred embodiment, the application conditions are: the hydroisomerization catalyst and raw materials are added to a high-pressure reaction kettle, the reaction temperature is 280-350°C, the hydrogen pressure is 3.0-5.0MPa, the reaction time is 2-5 hours, and the catalyst dosage is 4%-20% of the mass of the raw materials.

[0061] Further, the raw materials are at least one of plant and animal oils such as palm oil and rapeseed oil.

[0062] Another aspect of the present application provides the use of the hydroisomerization catalyst in improving the yield of C10-C16 isoparaffins in bio-jet fuel.

[0063] In order to more clearly and specifically introduce the hydrogen isomerization catalyst provided by the embodiments of the present application, the preparation method and application thereof, the following will be described in combination with specific embodiments.

[0064] In the following embodiments and comparative examples of the present application, the SAPO-11 molecular sieve is purchased from Raodong New Material Co., Ltd., the Si:Al:P molar ratio is 0.2:1:1, the specific surface area is 280-320 m 2 / g, and the micropore size is 0.5-0.6 nm.

[0065] The ZSM-5 molecular sieve is purchased from Dalian Zel Catalytic Material Co., Ltd., the specific surface area is 350-400 m 2 / g, and the mesopore size is 10-30 nm.

[0066] Example 1: Preparation of a hydrogen isomerization catalyst

[0067] (1) Preparation of a modified composite carrier: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) and 3 g of ZSM-5 (Si / Al = 80) are mixed, and a water solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate is added, 50 mL, stirred at 60℃ for 2 hours, dried at 110℃ for 12 hours, and calcined at 550℃ for 4 hours to obtain a composite carrier;

[0068] (2) Metal loading: 0.12 g of H2PtCl6, 0.05 g of IrCl3, and 0.02 g of PdCl2 are mixed with 5 g of the composite carrier, dissolved in 20 mL of ethanol, stirred at 60℃ for 3 hours, dried at 110℃ for 12 hours, and calcined at 500℃ for 3 hours, ground and sieved to obtain a primary product;

[0069] (3) Pore structure optimization and reduction: 4 g of the above primary product is dissolved in 100 mL of a 30wt% aqueous solution of tetrapropylammonium bromide, reacted at 170℃ for 72 hours, filtered and dried, and then reduced at 400℃ under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydrogen isomerization catalyst.

[0070] The content of the metal elements is measured by X-ray fluorescence spectroscopy, and each sample is measured repeatedly for 3 times to obtain an average value. The test results show that, in the hydrogen isomerization catalyst, the content of Pt is 0.85wt% of the total mass of the hydrogen isomerization catalyst, the content of Ir is 0.32wt% of the total mass of the hydrogen isomerization catalyst, and the content of Pd is 0.21wt% of the total mass of the hydrogen isomerization catalyst. Figure 1 The morphology test diagram of the hydrogen isomerization catalyst prepared in the present embodiment.

[0071] Example 2: Preparation of a hydrogen isomerization catalyst

[0072] (1) Preparation of modified composite carrier: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) and 3 g of ZSM-5 (Si / Al = 80) were mixed, 10 mL of an aqueous solution containing 0.1 g of lanthanum nitrate and 0.05 g of ammonium dihydrogen phosphate was added, stirring at 60°C for 2 hours, drying at 110°C for 12 hours, and calcining at 500°C for 5 hours to obtain a composite carrier;

[0073] (2) Metal loading: 0.08 g of H2PtCl6, 0.03 g of IrCl3, and 0.01 g of PdCl2 were mixed with 5 g of the composite carrier, dissolved in 15 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, and calcined at 400°C for 4 hours to obtain a primary product;

[0074] (3) Pore structure optimization and reduction: 4 g of the primary product was dissolved in 80 mL of a 10 wt% aqueous solution of tetrapropylammonium bromide, reacted at 100°C for 100 hours, dried after filtration, and reduced at 300°C under a hydrogen flow of 20 mL / min for 4 hours to obtain a hydroisomerization catalyst.

[0075] The content of metal elements was measured by X-ray fluorescence spectroscopy, and each sample was measured three times to obtain an average value. The test results showed that, in the hydroisomerization catalyst, the content of Pt was 0.76 wt% of the total mass of the hydroisomerization catalyst, the content of Ir was 0.21 wt% of the total mass of the hydroisomerization catalyst, and the content of Pd was 0.11 wt% of the total mass of the hydroisomerization catalyst.

[0076] Example 3: Preparation of a hydroisomerization catalyst

[0077] (1) Preparation of modified composite carrier: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) and 3 g of ZSM-5 (Si / Al = 80) were mixed, 30 mL of an aqueous solution containing 0.2 g of lanthanum nitrate and 0.1 g of diammonium hydrogen phosphate was added, stirring at 60°C for 2 hours, drying at 110°C for 12 hours, and calcining at 600°C for 3 hours to obtain a composite carrier;

[0078] (2) Metal loading: 0.15 g of H2PtCl6, 0.08 g of IrCl3, and 0.04 g of PdCl2 were mixed with 5 g of the composite carrier, dissolved in 25 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, and calcined at 600°C for 2 hours to obtain a primary product;

[0079] (3) Pore structure optimization and reduction: 4 g of the primary product was dissolved in 200 mL of a 60 wt% aqueous solution of tetrapropylammonium bromide, reacted at 250°C for 5 hours, dried after filtration, and reduced at 500°C under a hydrogen flow of 50 mL / min for 2 hours to obtain a hydroisomerization catalyst.

[0080] The content of metal elements was measured by X-ray fluorescence spectrometry, and each sample was measured 3 times to take the average value. The test showed that, in the hydrogen isomerization catalyst, the content of Pt was 0.98wt% of the total mass of the hydrogen isomerization catalyst, the content of Ir was 0.51wt% of the total mass of the hydrogen isomerization catalyst, and the content of Pd was 0.32wt% of the total mass of the hydrogen isomerization catalyst.

[0081] Comparative Example 1

[0082] (1) Preparation of modified composite carrier: 10 g of SAPO-11 (Si:Al:P = 0.2:1:1) molecular sieve was added with a 50 mL aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate, stirred at 60°C for 2 hours, dried at 110°C for 12 hours, and calcined at 550°C for 4 hours to obtain a composite carrier;

[0083] (2) Metal loading: 0.12 g of H2PtCl6, 0.05 g of IrCl3, and 0.02 g of PdCl2 were mixed with 5 g of the composite carrier, dissolved in 20 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, calcined at 500°C for 3 hours, ground and sieved to obtain a primary product;

[0084] (3) Pore structure optimization and reduction: 4 g of the above primary product was dissolved in 100 mL of a 30wt% tetrapropylammonium bromide aqueous solution, reacted at 170°C for 72 hours, dried after filtration, and reduced at 400°C under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydrogen isomerization catalyst.

[0085] Comparative Example 2

[0086] (1) Preparation of modified composite carrier: 10 g of ZSM-5 (Si / Al = 80) was added with a 50 mL aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate, stirred at 60°C for 2 hours, dried at 110°C for 12 hours, and calcined at 550°C for 4 hours to obtain a composite carrier;

[0087] (2) Metal loading: 0.12 g of H2PtCl6, 0.05 g of IrCl3, and 0.02 g of PdCl2 were mixed with 5 g of the composite carrier, dissolved in 20 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, calcined at 500°C for 3 hours, ground and sieved to obtain a primary product;

[0088] (3) Pore structure optimization and reduction: 4 g of the above primary product was dissolved in 100 mL of a 30wt% tetrapropylammonium bromide aqueous solution, reacted at 170°C for 72 hours, dried after filtration, and reduced at 400°C under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydrogen isomerization catalyst.

[0089] Comparative Example 3

[0090] (1) Preparation of modified composite support: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) was mixed with 3 g of ZSM-5 (Si / Al = 80), 50 mL of water was added, stirring at 60°C for 2 hours, drying at 110°C for 12 hours, calcining at 550°C for 4 hours, to obtain a composite support;

[0091] (2) Metal loading: 0.12 g of H2PtCl6, 0.05 g of IrCl3, and 0.02 g of PdCl2 were mixed with 5 g of the composite support, dissolved in 20 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, calcined at 500°C for 3 hours, ground and sieved to obtain a primary product;

[0092] (3) Pore structure optimization and reduction: 4 g of the above primary product was dissolved in 100 mL of 30wt% tetrapropylammonium bromide aqueous solution, reacted at 170°C for 72 hours, dried after filtration, and reduced at 400°C under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydrogenation isomerization catalyst.

[0093] Comparative Example 4

[0094] (1) Preparation of modified composite support: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) was mixed with 3 g of ZSM-5 (Si / Al = 80), 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate was added, stirring at 60°C for 2 hours, drying at 110°C for 12 hours, calcining at 550°C for 4 hours, to obtain a composite support;

[0095] (2) Metal loading: 0.12 g of H2PtCl6, 0.05 g of IrCl3, and 0.02 g of PdCl2 were mixed with 5 g of the composite support, dissolved in 20 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, calcined at 500°C for 3 hours, ground and sieved to obtain a primary product;

[0096] (3) Pore structure optimization and reduction: 4 g of the above primary product was dissolved in 100 mL of 30wt% tetrapropylammonium bromide aqueous solution, reacted at 170°C for 72 hours, dried after filtration, and reduced at 400°C under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydrogenation isomerization catalyst.

[0097] Comparative Example 5

[0098] (1) Preparation of modified composite support: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) was mixed with 3 g of ZSM-5 (Si / Al = 80), 50 mL of an aqueous solution containing 0.08 g of ammonium dihydrogen phosphate was added, stirring at 60°C for 2 hours, drying at 110°C for 12 hours, calcining at 550°C for 4 hours, to obtain a composite support;

[0099] (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 were mixed with 5 g of the composite support, dissolved in 20 mL of ethanol, stirred at 60 °C for 3 hours, dried at 110 °C for 12 hours, calcined at 500 °C for 3 hours, ground and sieved to obtain the primary product;

[0100] (3) Pore structure optimization and reduction: 4 g of the primary product was dissolved in 100 mL of 30 wt% aqueous tetrapropylammonium bromide solution, reacted at 170 °C for 72 hours, dried after filtration, and reduced at 400 °C under a hydrogen flow of 30 mL / min for 3 hours to obtain the hydrogenation isomerization catalyst.

[0101] Comparative Example 6

[0102] (1) Preparation of modified composite support: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) was mixed with 3 g of ZSM-5 (Si / Al = 80), 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate was added, stirred at 60 °C for 2 hours, dried at 110 °C for 12 hours, calcined at 550 °C for 4 hours to obtain the composite support;

[0103] (2) Metal loading: 0.12 g H2PtCl6 was mixed with 5 g of the composite support, dissolved in 20 mL of ethanol, stirred at 60 °C for 3 hours, dried at 110 °C for 12 hours, calcined at 500 °C for 3 hours, ground and sieved to obtain the primary product;

[0104] (3) Pore structure optimization and reduction: 4 g of the primary product was dissolved in 100 mL of 30 wt% aqueous tetrapropylammonium bromide solution, reacted at 170 °C for 72 hours, dried after filtration, and reduced at 400 °C under a hydrogen flow of 30 mL / min for 3 hours to obtain the hydrogenation isomerization catalyst.

[0105] Comparative Example 7

[0106] (1) Preparation of modified composite support: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) was mixed with 3 g of ZSM-5 (Si / Al = 80), 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate was added, stirred at 60 °C for 2 hours, dried at 110 °C for 12 hours, calcined at 550 °C for 4 hours to obtain the composite support;

[0107] (2) Metal loading: 0.05 g IrCl3 was mixed with 5 g of the composite support, dissolved in 20 mL of ethanol, stirred at 60 °C for 3 hours, dried at 110 °C for 12 hours, calcined at 500 °C for 3 hours, ground and sieved to obtain the primary product;

[0108] (3) Pore structure optimization and reduction: 4 g of the above initial product was dissolved in 100 mL of 30 wt% tetrapropylammonium bromide aqueous solution, reacted at 170°C for 72 hours, dried after filtration, and reduced at 400°C under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydrogenation isomerization catalyst.

[0109] Comparative Example 8

[0110] (1) Preparation of modified composite carrier: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) was mixed with 3 g of ZSM-5 (Si / Al = 80), 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate was added, stirred at 60°C for 2 hours, dried at 110°C for 12 hours, and calcined at 550°C for 4 hours to obtain a composite carrier;

[0111] (2) Metal loading: 0.02 g of PdCl2 was mixed with 5 g of the composite carrier, dissolved in 20 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, calcined at 500°C for 3 hours, ground and sieved to obtain an initial product;

[0112] (3) Pore structure optimization and reduction: 4 g of the above initial product was dissolved in 100 mL of 30 wt% tetrapropylammonium bromide aqueous solution, reacted at 170°C for 72 hours, dried after filtration, and reduced at 400°C under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydrogenation isomerization catalyst.

[0113] Comparative Example 9

[0114] (1) Preparation of modified composite carrier: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) was mixed with 3 g of ZSM-5 (Si / Al = 80), 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate was added, stirred at 60°C for 2 hours, dried at 110°C for 12 hours, and calcined at 550°C for 4 hours to obtain a composite carrier;

[0115] (2) Metal loading: 0.12 g of H2PtCl6, 0.05 g of IrCl3, and 0.02 g of PdCl2 were mixed with 5 g of the composite carrier, dissolved in 20 mL of ethanol, stirred at 60°C for 3 hours, dried at 110°C for 12 hours, calcined at 500°C for 3 hours, ground and sieved to obtain an initial product.

[0116] Comparative Example 10

[0117] (1) Preparation of modified composite carrier: 7 g of SAPO-11 (Si:Al:P = 0.2:1:1) and 3 g of ZSM-5 (Si / Al = 80) were mixed, 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate was added, stirring was carried out at 60°C for 2 hours, drying was carried out at 110°C for 12 hours, and calcination was carried out at 550°C for 4 hours to obtain a composite carrier;

[0118] (2) Metal loading: 0.12 g of Ni(NO3)2, 0.08 g of MoO3 and 5 g of the composite carrier were mixed, dissolved in 20 mL of ethanol, stirring was carried out at 60°C for 3 hours, drying was carried out at 110°C for 12 hours, and calcination was carried out at 500°C for 3 hours to obtain a primary product;

[0119] (3) Pore structure optimization and reduction: 4 g of the primary product was dissolved in 100 mL of a 30wt% aqueous solution of tetrapropylammonium bromide, and reaction was carried out at 170°C for 72 hours. After filtration and drying, reduction was carried out at 400°C under a hydrogen flow of 30 mL / min for 3 hours to obtain a hydroisomerization catalyst.

[0120] Application Example 1

[0121] Palm oil was used as a raw material, and the palm oil and the hydroisomerization catalyst prepared in Example 1 were added to a high-pressure reaction kettle. The catalyst dosage was 4% of the mass of the raw material. The reaction was carried out at a reaction temperature of 300°C and a hydrogen pressure of 4 MPa for 3 h to obtain a reaction product. The reaction product was subjected to rectification to cut C10-C16 fractions to obtain a bio-jet fuel product.

[0122] Application Example 2

[0123] Palm oil was used as a raw material, and the palm oil and the hydroisomerization catalyst prepared in Example 2 were added to a high-pressure reaction kettle. The catalyst dosage was 7% of the mass of the raw material. The reaction was carried out at a reaction temperature of 280°C and a hydrogen pressure of 3 MPa for 5 h to obtain a reaction product. The reaction product was subjected to rectification to cut C10-C16 fractions to obtain a bio-jet fuel product.

[0124] Application Example 3

[0125] Rapeseed oil was used as a raw material, and the rapeseed oil and the hydroisomerization catalyst prepared in Example 3 were added to a high-pressure reaction kettle. The catalyst dosage was 10% of the mass of the raw material. The reaction was carried out at a reaction temperature of 350°C and a hydrogen pressure of 5 MPa for 2 h to obtain a reaction product. The reaction product was subjected to rectification to cut C10-C16 fractions to obtain a bio-jet fuel product.

[0126] Test Example 1

[0127] The density (20℃), freezing point and kinematic viscosity (-20℃) of the bio-jet fuel products prepared by using examples 1-3 were tested according to GB / T 1884-2000 "Determination of the density of crude petroleum and liquid petroleum products - Laboratory method (hydrometer method)", GB / T 2430-2008 "Determination of the freezing point of jet fuel", GB / T 265-1988 "Determination of the kinematic viscosity of petroleum products - Laboratory method and calculation of kinematic viscosity", and the test results are shown in Table 1.

[0128] Table 1 Performance test of different bio-jet fuel products

[0129]

[0130] As shown in Table 1, the density (20℃) of the bio-jet fuel products prepared by using the hydrogen isomerization catalysts prepared by examples 1-3 is 0.79-0.81 g / cm 3 , the freezing point is ≤-47℃, and the kinematic viscosity (-20℃) is ≥1.5 mm 2 / s, which meets the ASTMD7566 bio-jet fuel standard.

[0131] Test example 2: Activity test of different catalysts

[0132] The activity of the hydrogen isomerization catalysts prepared by examples 1-3 and comparative examples 1-10 was evaluated.

[0133] Palm oil was used as the raw material, and the hydrogen isomerization catalysts prepared by examples 1-3 and comparative examples 1-10 were used as the catalysts, which were added into a high-pressure reaction kettle for reaction, under the conditions of a reaction temperature of 320℃, a hydrogen pressure of 4 MPa, a reaction time of 3 h, and a catalyst amount of 10% of the mass of the raw material, to obtain a reaction product.

[0134] The reaction product was determined to calculate the cracking rate (<C10 product proportion), C10-C16 isomeric alkane yield, isomerization selectivity and 1000 h stability.

[0135] 1. Test method:

[0136] 1.1 Cracking rate (%)

[0137] Definition: refers to the mass percentage of hydrocarbons with a carbon number less than 10 (<C10 product) in the total product.

[0138] Calculation method: the total mass of <C10 product was determined by component analysis of the reaction product by gas chromatography and the like, and then divided by the total mass of the reaction product and multiplied by 100% to obtain.

[0139] 1.2 C10-C16 isomeric alkane yield (%)

[0140] Definition: refers to the percentage of isomeric alkanes with carbon number 10-16 in the total mass of the raw material.

[0141] Calculation method: the total mass of C10-C16 isomeric alkanes in the product is analyzed by gas chromatography, divided by the initial mass of the raw material (such as palm oil) involved in the reaction, multiplied by 100% to obtain.

[0142] 1.3 Isomerization selectivity (%)

[0143] Definition: refers to the proportion of isomeric alkanes in all alkanes (including normal alkanes and isomeric alkanes) in the product, for the C10-C16 fraction.

[0144] Calculation method: the mass of isomeric alkanes and the mass of normal alkanes in the C10-C16 fraction are determined by chromatographic analysis, and the mass of isomeric alkanes is divided by (the mass of isomeric alkanes + the mass of normal alkanes), and then multiplied by 100% to obtain.

[0145] 1.4 1000h activity reduction (%)

[0146] Definition: refers to the proportion of the activity reduction of the catalyst after 1000 hours of continuous operation relative to the initial activity (calculated based on the key indicator C10-C16 isomeric alkane yield).

[0147] Calculation method: the activity indicators (C10-C16 isomeric alkane yield) of the catalyst at the initial time and after 1000 hours of operation are determined, and (initial activity-1000h activity) / initial activity x 100% is obtained.

[0148] 2、Test results:

[0149] Table 2 Activity test of different catalysts

[0150]

[0151] From the test data in Table 2, it can be clearly seen that the hydrogen isomerization catalysts prepared in Examples 1-3 have significant advantages in the preparation of bio-jet fuel. Specifically, Examples 1-3 use SAPO-11 / ZSM-5 (7:3) composite carriers, and the cracking rate is only 8.8%-10.0%, and the C10-C16 isomeric alkane yield is 76.2%-79.3%; while Comparative Example 1 uses a single SAPO-11 or ZSM-5 carrier, the cracking rate increases to 18.5%-25.3%, and the yield decreases to 59.7%-65.1%, indicating that the combination of SAPO-11 or ZSM-5 carriers plays a synergistic role in reducing the cracking rate and increasing the C10-C16 isomeric alkane yield.

[0152] In addition, examples 1-3 adopt the Pt-Ir-Pd three-metal combination matched with La2O3+P additives, the isomerization selectivity reaches 89.5%-92.0%, and the activity reduction in 1000h is only 4.2%-5.0%; the comparative example 3 does not add additives, the comparative examples 4-5 add one kind of additive respectively, the comparative examples 6-8 load single Pt, Ir and Pd metal respectively, the C10-C16 isomeric alkane yield and isomerization selectivity are significantly reduced, which indicates that the electronic synergy of the three metals and the acid regulation effect of the additives are the core to improve the selectivity and stability.

[0153] The comparative example 9 omits the pore structure optimization step, and the yield and stability are both inferior to examples 1-3; the comparative example 10 adopts the traditional Ni-Mo system, the cracking rate is as high as 32.5%, and the yield is only 53.7%, which further proves the importance of the pore structure optimization step and the Pt-Ir-Pd noble metal system in the application to weaken the cracking and improve the target product yield.

[0154] In summary, the application realizes the technical effects of reducing the cracking rate, improving the target isomeric alkane yield and selectivity, and enhancing the stability through the synergistic design of the composite carrier, the three-metal active component and the La2O3+P additive, which is significantly superior to the scheme of single carrier, single metal, missing additives or traditional metal system, and provides a reliable catalyst solution for the efficient preparation of bio-jet fuel.

Claims

1. A hydroisomerization catalyst characterized in that, The hydrogenation isomerization catalyst comprises a composite carrier and a catalytically active component supported on the composite carrier; The composite carrier is a SAPO-11 / ZSM-5 composite molecular sieve modified by La2O3 and P; The composite carrier has a mesopore-micropore multi-level pore structure, wherein the pore size of the mesopore is 10-30 nm, the pore size of the micropore is 0.5-0.6 nm, and the total pore volume is >0.8 cm 3 / g; The catalytically active component is a combination of Pt, Ir and Pd; The content of the catalytically active component is calculated based on the metal element, wherein the content of Pt is 0.5-1.0 wt% of the total mass of the hydrogenation isomerization catalyst, the content of Ir is 0.2-0.5 wt% of the total mass of the hydrogenation isomerization catalyst, and the content of Pd is 0.1-0.3 wt% of the total mass of the hydrogenation isomerization catalyst; The composite carrier is prepared by the following method: The SAPO-11 / ZSM-5 composite molecular sieve is obtained by mixing SAPO-11 molecular sieve and ZSM-5 molecular sieve at a mass ratio of (7-8):(2-3); The La2O3 precursor and the P precursor are dissolved in water to obtain a mixed solution; The SAPO-11 / ZSM-5 composite molecular sieve is added to the mixed solution, stirred at 25-100℃, dried to remove the solvent, and then calcined at 500-600℃ for 3-5 hours to obtain the composite carrier; The content of the La2O3 precursor is 1-2% of the mass of the SAPO-11 / ZSM-5 composite molecular sieve, and the content of the P precursor is 0.5-1% of the mass of the SAPO-11 / ZSM-5 composite molecular sieve; The ratio of the addition amount of the SAPO-11 / ZSM-5 composite molecular sieve to the mixed solution is 1g:1-10mL; By means of metal synergy weakening cracking activity, carrier acidity and pore structure adaptation C10-C16 isomerization, and auxiliary control stability, the cracking rate of <C10 product is reduced to 8-10%, the yield of C10-C16 isomerized alkanes is increased to 75-80%, the isomerization selectivity is 88-92%, and the activity is reduced by ≤5% after 1000h.

2. The hydroisomerization catalyst of claim 1, wherein The silicon-aluminum ratio of the ZSM-5 molecular sieve is 50-100.

3. The process for preparing a hydroisomerization catalyst according to any one of claims 1 to 2, characterized in that, The method comprises a catalytically active component supporting step and a pore structure optimization step; The catalytically active component supporting step comprises: The Pt metal salt, the Ir metal salt and the Pd metal salt are mixed with the composite carrier, dissolved in a solvent, stirred uniformly, dried, and then calcined to obtain a primary product; The pore structure optimization step comprises: The primary product is added to a tetrapropylammonium bromide aqueous solution, reacted at 100-250℃ for 5-100 hours, filtered, dried, and then subjected to reduction treatment to obtain the hydrogenation isomerization catalyst.

4. The preparation method according to claim 3, characterized in that, In the catalytically active component supporting step, the solvent is water or ethanol; the calcination temperature is 400-600℃, and the time is 2-4 hours.

5. The preparation method according to claim 3, characterized in that, In the pore structure optimization step, the mass fraction of the tetrapropylammonium bromide aqueous solution is 10%-60%, and the ratio of the addition amount of the primary product to the tetrapropylammonium bromide aqueous solution is 1g:10-50mL; The reduction treatment conditions are: reduction in a hydrogen atmosphere at 300-500℃ for 2-4 hours, and the hydrogen flow rate is 20-50mL / min.

6. Use of the hydrogenation isomerization catalyst of any one of claims 1-2 in the catalytic preparation of bio-jet fuel.

7. Use of the hydroisomerization catalyst of any one of claims 1-2 to increase the yield of C10-C16 isomeric alkanes in bio-jet fuel.

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