Hydroisomerization catalyst as well as preparation method and application thereof

Abstract

The invention discloses a hydroisomerization catalyst and a preparation method and application thereof, and belongs to the technical field of biological aviation kerosene preparation. The hydroisomerization catalyst comprises a composite carrier and a catalytic active component loaded on the composite carrier, the composite carrier is an SAPO-11 / ZSM-5 composite molecular sieve which is modified by La2O3 and P; the composite carrier has a mesopore-micropore hierarchical pore structure, the pore diameter of mesopores is 10-30nm, the pore diameter of micropores is 0.5-0.6 nm, and the total pore volume is greater than or equal to 0.8 cm < 3 > / g; the catalytic active component is a combination of Pt, Ir and Pd. The method is applied to preparation of biological aviation kerosene, the cracking rate is reduced to 8-10%, the yield of C10-C16 isoparaffin is increased to 75-80%, the isomerization selectivity reaches 88-92%, the 1000h activity is reduced to be smaller than or equal to 5%, the catalyst can efficiently catalyze animal and vegetable oil and other raw materials to be directionally converted into the C10-C16 isoparaffin needed by the biological aviation kerosene, and the method is suitable for industrial production. The indexes of the biological aviation kerosene are improved, the C10-C16 isomerous components can be subsequently rectified and extracted, a product with a higher additional value is obtained, and the method is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of bio-aviation kerosene preparation, and in particular relates to a hydroisomerization catalyst and a preparation method and application thereof. Background Art

[0002] With the supply of traditional fossil energy becoming increasingly scarce and the pressure to reduce carbon dioxide emissions increasing, the development of renewable and clean alternative energy sources has become a global consensus. Bioenergy, due to its renewable and green nature, has attracted considerable attention in recent years and is considered an ideal solution to the global energy crisis. With the growing demand for biofuels, the technology for producing biojet fuel from renewable feedstocks is gaining increasing attention. Isoalkanes with carbon chain lengths in the C10-C16 range are key components of biojet fuel, and improving their yield is crucial to its quality.

[0003] In a previous paper (Study on the Preparation of Bio-Jet Fuel by One-Step Hydrogenation of Jatropha Oil. Yunnan Normal University, 2017), Hao Yajie et al. used Jatropha oil as the feedstock and a Pt / SAPO-11 catalyst as the catalyst. Through single-factor experiments, they explored the optimal reaction conditions for the production of bio-jet fuel by fixed-bed catalytic hydrogenation. They found a reaction temperature of 400°C, a reaction pressure of 5 MPa, a hydrogen-to-oil ratio of 1000, and a space velocity of 1.2 h⁻¹. Under these conditions, the product achieved a deoxygenation rate of 98.13%, a C8-C16 ratio of 45.38%, and a C8-C16 hydrocarbon isomerization rate of 32.49%. However, the use of a single Pt metal catalyst in this method resulted in a low yield of C8-C16 isoparaffins, hindering the subsequent extraction of high-value-added products. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is the low yield of C10-C16 isoparaffins in traditional bio-jet fuel hydroisomerization catalysts. A hydroisomerization catalyst is proposed, which weakens the cracking performance and improves the yield of C10-C16 isoparaffins by adopting a Pt-Ir-Pd trimetallic system, optimizing the support structure and coordinating the control of additives, as well as a preparation method and application thereof.

[0005] In order to solve the technical problem, the technical solution adopted by the present invention is: In one aspect, the present invention provides a hydroisomerization catalyst, comprising a composite support and a catalytically active component supported on the composite support; The composite support is a SAPO-11 / ZSM-5 composite molecular sieve modified with La2O3 and P; The composite carrier has a mesoporous-microporous multi-level pore structure, wherein the pore size of the mesopore is 10-30nm, the pore size of the micropore is 0.5-0.6nm, and the total pore volume is ≥0.8cm 3 / g; The catalytically active component is a combination of Pt, Ir, and Pd; The content of the catalytically active components is calculated as simple metal, 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.

[0006] Preferably, the composite carrier is prepared by the following method: 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; dissolving a La2O3 precursor and a P precursor in water to obtain a mixed solution; Add SAPO-11 / ZSM-5 composite molecular sieve into the mixed solution, stir at 25-100° C., dry to remove the solvent, and then calcine at 500-600° C. for 3-5 hours to obtain a composite carrier.

[0007] Preferably, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 50-100.

[0008] Preferably, 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; The ratio of the added amount of the SAPO-11 / ZSM-5 composite molecular sieve to the mixed solution is 1 g: 1-10 mL.

[0009] Another aspect of the present invention provides a method for preparing the above hydroisomerization catalyst, comprising a catalytically active component loading step and a pore structure optimization step; The catalytically active component loading step comprises: Pt metal salt, Ir metal salt, Pd metal salt and composite support are mixed and dissolved in a solvent, stirred evenly, 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° C. for 5-100 hours, filtered, dried, and then reduced to obtain a hydroisomerization catalyst.

[0010] Preferably, in the step of loading the catalytic active component, the solvent is water or ethanol; the calcination temperature is 400 - 600 °C, and the time is 2 - 4 hours.

[0011] Preferably, in the step of optimizing the pore structure, the mass fraction of the tetrapropylammonium bromide aqueous solution is 10% - 60%, and the ratio of the amount of the initial product to the amount of the tetrapropylammonium bromide aqueous solution added is 1 g: 10 - 50 mL; 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 - 50 mL / min.

[0012] On the other hand, the present invention provides the application of the above hydrogenation isomerization catalyst in the catalytic preparation of bio - aviation kerosene.

[0013] On the other hand, the present invention provides the application of the above hydrogenation isomerization catalyst in improving the yield of C10 - C16 isoparaffins in bio - aviation kerosene.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a hydrogenation isomerization catalyst. This hydrogenation isomerization catalyst uses SAPO - 11 / ZSM - 5 as a composite support, has a mesoporous - microporous hierarchical pore structure, loads a Pt - Ir - Pd metal combination, and introduces La2O3 and P as composite promoters. By weakening the cracking activity through metal synergy, matching the carrier acidity and pore structure for C10 - C16 isomerization, and regulating the stability performance by the promoters, the cracking rate (<C10 product) is reduced to 8 - 10%, the yield of C10 - C16 isoparaffins is increased to 75 - 80%, the isomerization selectivity reaches 88 - 92%, and the activity decline within 1000 h is ≤5%. This catalyst can efficiently catalyze the directional conversion of raw materials such as animal and vegetable oils into C10 - C16 isoparaffins required for bio - aviation kerosene. While improving the bio - aviation kerosene index, the subsequent rectification extraction of C10 - C16 isomeric components can be carried out to obtain products with higher added value, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a morphology test diagram of the hydrogenation isomerization catalyst provided in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Hereinafter, the technical solutions in the specific embodiments of the present invention will be described in detail and completely with reference to the drawings. Obviously, the described embodiments are only partial specific embodiments of the general technical solution of the present invention, rather than all embodiments. Based on the general concept of the present invention, all other embodiments obtained by those of ordinary skill in the art fall within the protection scope of the present invention.

[0017] On the one hand, the present invention provides a hydrogenation isomerization catalyst, which includes a composite support and a catalytic active component loaded on the composite support; The composite support is a SAPO-11 / ZSM-5 composite molecular sieve modified with La2O3 and P; The composite support has a mesoporous-microporous hierarchical pore structure. Among them, the pore diameter of the mesopores is 10-30 nm, the pore diameter of the micropores is 0.5-0.6 nm, and the total pore volume ≥ 0.8 cm 3 / g; The catalytic active components are a combination of Pt, Ir, and Pd.

[0018] It should be noted that isoparaffins with a carbon chain length in the range of C10-C16 are the key components of bio-aviation fuel. Improving their yield is crucial for the quality of bio-aviation fuel. However, the currently commonly used bio-aviation fuel hydroisomerization catalysts still have obvious defects: First, there are defects in the metal system. Usually, metals such as Ni and Mo (single components or simple mixtures) are used. Their strong cracking activity leads to excessive cracking of long-chain alkanes, generating a large number of <C10 small molecules, and the retention rate of C10-C16 precursors is low. Second, the carrier performance is insufficient. Traditional catalysts mostly use single molecular sieves, such as single ZSM-5 molecular sieve. It has many strong acidic sites, which easily trigger excessive cracking reactions. Moreover, the pore structure of the traditional catalyst carrier has not been optimized for the characteristics of C10-C16 molecules, and the diffusion limitation is obvious. Finally, the existing bio-aviation fuel hydroisomerization catalysts have no acidic regulation additives, which cannot effectively weaken the strong acid sites and stabilize the metal dispersion, resulting in fast catalyst carbon deposition and poor stability, affecting the continuous generation of C10-C16 isoparaffins. In summary, traditional bio-aviation fuel hydroisomerization catalysts are difficult to balance the synergistic effect of cracking and isomerization, resulting in a C10-C16 isoparaffin yield of only 60%-65%, which is not conducive to the extraction of subsequent high-value-added products.

[0019] To address the above problems, the present invention specifies the selection of La2O3 and P as acidic regulation additives. The reason is that La2O3 neutralizes some strong acid sites, reducing C-C bond cleavage; P enhances the interaction between the carrier and the metal, avoids the agglomeration of Pt-Ir, and improves the metal dispersion. The cooperation of the additives can reduce the probability of catalyst carbon deposition, thereby increasing the lifespan of the catalyst and ensuring the long-term stable production of C10-C16 isoparaffins. The above technical solution also specifies the selection of SAPO-11 / ZSM-5 composite molecular sieve. The reason is that SAPO-11 molecular sieve provides weak-medium acidic sites and elliptical ten-membered ring channels (0.39×0.63 nm), which play a shape-selective isomerization role for C10-C16 long-chain alkanes; ZSM-5 retains moderate cracking activity (only cracking C17+ to C10-C16), and配合介孔-微孔多级孔结构,介孔(10-30nm)促进C10-C16分子扩散,微孔(0.5-0.6nm)限制过度裂解,总孔容≥0.8cm 3 / g, which not only limits excessive cracking but also promotes the diffusion of C10-C16 molecules, thus significantly improving the isomerization efficiency; In addition, the present invention adopts the Pt-Ir-Pd trimetallic system to replace the traditional metal system based on Ni and Mo, wherein Pt-Ir is complementary to Ir through electrons (5d 7 The electronic configuration reduces the binding energy with the CC bond) weakens the ability to dissociate the CC bond and reduces the excessive breakage of long-chain alkanes; Pd inhibits carbon deposition to ensure diffusion, reduces the cracking rate, and improves the C10-C16 yield.

[0020] In a preferred embodiment, the content of the catalytically active components, calculated as metal elements, is 0.5-1.0 wt% of the total mass of the hydroisomerization catalyst for Pt, 0.2-0.5 wt% of the total mass of the hydroisomerization catalyst for Ir, and 0.1-0.3 wt% of the total mass of the hydroisomerization catalyst for Pd.

[0021] The above technical solution limits the content of Pt, Ir, and Pd, wherein Pt acts as the main active center and retains high hydrogenation isomerization activity; Ir forms an electronic synergy with Pd, and its 5d 7 The electronic configuration reduces the binding energy with the CC bond (about 8 kJ / mol lower than Ni), reducing cracking; trace amounts of Pd inhibit carbon deposition in olefin polymerization and improve product diffusion.

[0022] In a preferred embodiment, the composite carrier is prepared by the following method: 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; dissolving a La2O3 precursor and a P precursor in water to obtain a mixed solution; Add SAPO-11 / ZSM-5 composite molecular sieve into the mixed solution, stir at 25-100° C., dry to remove the solvent, and then calcine at 500-600° C. for 3-5 hours to obtain a composite carrier.

[0023] In the preparation steps of the above-mentioned composite carrier, the mass ratio of SAPO-11 molecular sieve to ZSM-5 molecular sieve is (7-8): (2-3). The reason is that this ratio can balance isomerization and moderate cracking activity: if the proportion of SAPO-11 is too high, C17+ long-chain alkanes cannot be effectively broken down into C10-C16, while if the proportion is too low, excessive cracking will be aggravated. In addition, in the above-mentioned preparation steps, the stirring temperature is controlled at 25-100°C to ensure that the precursor is evenly dispersed on the surface of the molecular sieve, avoiding uneven distribution of acidic sites caused by local aggregation.

[0024] In a preferred embodiment, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 50-100.

[0025] The above technical solution defines the silica-alumina ratio of ZSM-5 molecular sieve to be 50-100. The reason is that high-silica-alumina ZSM-5 (Si / Al = 50-100) retains moderate cracking activity (only breaks C17+), which can avoid excessive breaking of C10-C16 carbon chains. If the silica-alumina ratio is lower than 50, it will lead to an increase in <C10 products.

[0026] 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; The ratio of the addition amount of the SAPO-11 / ZSM-5 composite molecular sieve to the mixed solution is 1 g: 1-10 mL.

[0027] In a preferred embodiment, the La2O3 precursor is one or more of lanthanum nitrate, lanthanum chloride, and lanthanum acetate; the P precursor is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and ammonium phosphate.

[0028] On the other hand, the present invention provides a method for preparing the above hydroisomerization catalyst, including a catalytic active component loading step; The catalytic active component loading step includes: Mix the Pt metal salt, Ir metal salt, and Pd metal salt with the composite support, dissolve them in a solvent, stir evenly, dry, and then calcine to obtain a primary product.

[0029] 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; the Pd metal salt can be one or more of PdCl2, Pd(NO3)2, and Pd(NH3)4Cl2.

[0030] In a preferred embodiment, in the catalytic active component loading step, the solvent is water or ethanol; the stirring temperature is 25-100 °C; the calcination temperature is 400-600 °C, and the time is 2-4 hours.

[0031] In a preferred embodiment, the method for preparing the above hydroisomerization catalyst further includes a pore structure optimization step; The pore structure optimization step includes: Add the primary product to an aqueous solution of tetrapropylammonium bromide, react at 100-250 °C for 5-100 hours, filter, dry, and then perform a reduction treatment to obtain the hydroisomerization catalyst.

[0032] In a preferred embodiment, in the pore structure optimization step, the mass fraction of the tetrapropylammonium bromide aqueous solution is 10%-60%, and the ratio of the added amount of the primary product to the tetrapropylammonium bromide aqueous solution is 1 g:10-50 mL; the reduction treatment conditions are: reduction at 300-500° C. in a hydrogen atmosphere for 2-4 hours, and a hydrogen flow rate of 20-50 mL / min.

[0033] In the above-mentioned pore structure optimization step, tetrapropylammonium bromide is used as a mesoporous template. Its concentration and liquid-to-solid ratio can regulate the mesopore size and distribution, ensuring that the mesopore diameter is stable at 10-30nm; the reduction treatment can completely convert the metal oxide into a catalytically active metal element, and the hydrogen flow rate and temperature can avoid sintering of metal particles.

[0034] Another aspect of the present invention provides the use of the above hydroisomerization catalyst in the catalytic preparation of bio-jet fuel.

[0035] In a preferred embodiment, the application conditions are as follows: the above-mentioned hydroisomerization catalyst and raw materials are added to a high-pressure reactor, the reaction temperature is 280-350°C, the hydrogen pressure is 3.0-5.0 MPa, the reaction time is 2-5 hours, and the catalyst dosage is 4%-20% of the raw material mass.

[0036] Furthermore, the raw material is at least one of animal and vegetable oils such as palm oil and rapeseed oil.

[0037] Another aspect of the present invention provides the use of the above-mentioned hydroisomerization catalyst in improving the yield of C10-C16 isoparaffins in bio-jet fuel.

[0038] In order to more clearly and in detail introduce a hydroisomerization catalyst and its preparation method and application provided by the embodiments of the present invention, they will be described below with reference to specific embodiments.

[0039] In the following examples and comparative examples of the present invention, SAPO-11 molecular sieve was purchased from Raodong New Materials Co., Ltd., with a Si:Al:P molar ratio of 0.2:1:1 and a specific surface area of ​​280-320m 2 / g, micropore diameter 0.5-0.6nm.

[0040] ZSM-5 molecular sieve was purchased from Dalian Zeer Catalytic Materials Co., Ltd., with a specific surface area of ​​350-400m 2 / g, mesopore diameter 10-30nm.

[0041] Example 1: Preparation of Hydroisomerization Catalyst (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 and 5 g composite support were mixed, dissolved in 20 mL ethanol, stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 500 °C for 3 h, ground and sieved to obtain the primary product; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0042] The metal content was measured using X-ray fluorescence spectroscopy, with each sample measured three times and the average value taken. The results showed that, based on the metal content, Pt accounted for 0.85 wt% of the total mass of the hydroisomerization catalyst, Ir accounted for 0.32 wt% of the total mass of the hydroisomerization catalyst, and Pd accounted for 0.21 wt% of the total mass of the hydroisomerization catalyst. Figure 1 This is a morphology test picture of the hydroisomerization catalyst prepared in this example.

[0043] Example 2: Preparation of Hydroisomerization Catalyst (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 500 °C for 5 h to obtain a composite support; (2) Metal loading: 0.08 g H2PtCl6, 0.03 g IrCl3, 0.01 g PdCl2 and 5 g composite support were mixed, dissolved in 15 mL ethanol, stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 400 °C for 4 h, ground and sieved to obtain the primary product; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 80 mL of 10 wt% tetrapropylammonium bromide aqueous solution and reacted at 100 °C for 100 h. After filtration and drying, the product was reduced at 300 °C and a hydrogen flow rate of 20 mL / min for 4 h to obtain a hydrogenation catalyst.

[0044] The metal content was measured using X-ray fluorescence spectroscopy, with each sample measured three times and the average value taken. The results showed that, based on the metal content, Pt accounted for 0.76 wt% of the total mass of the hydroisomerization catalyst, Ir accounted for 0.21 wt% of the total mass of the hydroisomerization catalyst, and Pd accounted for 0.11 wt% of the total mass of the hydroisomerization catalyst.

[0045] Example 3: Preparation of Hydroisomerization Catalyst (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 600 °C for 3 h to obtain a composite support; (2) Metal loading: 0.15 g H2PtCl6, 0.08 g IrCl3, 0.04 g PdCl2 and 5 g composite support were mixed and dissolved in 25 mL ethanol. The mixture was stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 600 °C for 2 h, and ground and sieved to obtain a primary product. (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 200 mL of a 60 wt% tetrapropylammonium bromide aqueous solution and reacted at 250 °C for 5 hours. After filtration and drying, the product was reduced at 500 °C and a hydrogen flow rate of 50 mL / min for 2 hours to obtain a hydrogenation catalyst.

[0046] The metal content was measured using X-ray fluorescence spectroscopy, with each sample measured three times and the average value taken. The results showed that, based on the metal content, Pt accounted for 0.98 wt% of the total mass of the hydroisomerization catalyst, Ir accounted for 0.51 wt% of the total mass of the hydroisomerization catalyst, and Pd accounted for 0.32 wt% of the total mass of the hydroisomerization catalyst.

[0047] Comparative Example 1 (1) Preparation of modified composite support: 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate was added to 10 g of SAPO-11 (Si:Al:P=0.2:1:1) molecular sieve, 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 support; (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 and 5 g composite support were mixed, dissolved in 20 mL ethanol, stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 500 °C for 3 h, ground and sieved to obtain the primary product; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0048] Comparative Example 2 (1) Preparation of modified composite support: 50 mL of an aqueous solution containing 0.15 g of lanthanum nitrate and 0.08 g of ammonium dihydrogen phosphate was added to 10 g of ZSM-5 (Si / Al=80), 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 support; (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 and 5 g composite support were mixed, dissolved in 20 mL ethanol, stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 500 °C for 3 h, ground and sieved to obtain the primary product; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0049] Comparative Example 3 (1) Preparation of modified composite support: 7 g SAPO-11 (Si:Al:P=0.2:1:1) and 3 g ZSM-5 (Si / Al=80) were mixed, 50 mL water was added, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 and 5 g composite support were mixed, dissolved in 20 mL ethanol, stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 500 °C for 3 h, ground and sieved to obtain the primary product; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0050] Comparative Example 4 (1) Preparation of modified composite support: 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 was added, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 and 5 g composite support were mixed, dissolved in 20 mL ethanol, stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 500 °C for 3 h, ground and sieved to obtain the primary product; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0051] Comparative Example 5 (1) Preparation of modified composite support: 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 0.08 g of ammonium dihydrogen phosphate was added, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 and 5 g composite support were mixed, dissolved in 20 mL ethanol, stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 500 °C for 3 h, ground and sieved to obtain the primary product; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0052] Comparative Example 6 (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.12 g of 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; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0053] Comparative Example 7 (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.05 g of 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; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0054] Comparative Example 8 (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.02 g of PdCl2 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; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0055] Comparative Example 9 (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.12 g H2PtCl6, 0.05 g IrCl3, 0.02 g PdCl2 and 5 g composite carrier were mixed and dissolved in 20 mL ethanol. The mixture was stirred at 60 °C for 3 h, dried at 110 °C for 12 h, calcined at 500 °C for 3 h, ground and sieved to obtain the primary product.

[0056] Comparative Example 10 (1) Preparation of modified composite support: 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, stirred at 60 °C for 2 h, dried at 110 °C for 12 h, and calcined at 550 °C for 4 h to obtain a composite support; (2) Metal loading: 0.12 g Ni(NO3)2, 0.08 g MoO3 and 5 g composite support were mixed, dissolved in 20 mL 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; (3) Pore structure optimization and reduction: 4 g of the above-mentioned primary product was dissolved in 100 mL of a 30 wt% tetrapropylammonium bromide aqueous solution and reacted at 170 °C for 72 h. After filtration and drying, the product was reduced at 400 °C and a hydrogen flow rate of 30 mL / min for 3 h to obtain a hydrogenation isomerization catalyst.

[0057] Application Example 1 Palm oil was used as raw material. Palm oil and the hydroisomerization catalyst prepared in Example 1 were added to a high-pressure reactor. The catalyst dosage was 4% of the raw material mass. The reaction was carried out at a reaction temperature of 300°C and a hydrogen pressure of 4 MPa for 3 hours to obtain a reaction product. The reaction product was then distilled to cut the C10-C16 fraction to obtain a bio-jet fuel product.

[0058] Application Example 2 Palm oil was used as raw material. Palm oil and the hydroisomerization catalyst prepared in Example 2 were added to a high-pressure reactor. The catalyst dosage was 7% of the raw material mass. The reaction was carried out at a reaction temperature of 280°C and a hydrogen pressure of 3 MPa for 5 hours to obtain a reaction product. The reaction product was then distilled to cut the C10-C16 fraction to obtain a bio-jet fuel product.

[0059] Application Example 3 Using rapeseed oil as raw material, rapeseed oil and the hydroisomerization catalyst prepared in Example 3 were added into a high-pressure reactor. The dosage of the catalyst was 10% of the raw material mass. Under the conditions of reaction temperature of 350 °C and hydrogen pressure of 5 MPa, the reaction was carried out for 2 h to obtain a reaction product. The reaction product was fractionated by distillation to cut C10-C16 fractions, and a bio-aviation fuel product was obtained.

[0060] Test Example 1 Referring to GB / T 1884-2000 "Laboratory Determination Method for Density of Crude Oil and Liquid Petroleum Products (Hydrometer Method)", GB / T 2430-2008 "Determination Method for Freezing Point of Jet Fuel", and GB / T 265-1988 "Determination Method for Kinematic Viscosity of Petroleum Products and Calculation Method for Dynamic Viscosity", the density (20 °C), freezing point, and kinematic viscosity (-20 °C) of the bio-aviation fuel products prepared in Application Examples 1-3 were tested. The test results are shown in Table 1.

[0061] Table 1 Performance Tests of Different Bio-aviation Fuel Products

[0062] As can be seen from Table 1, the density (20 °C) of the bio-aviation fuel products prepared by using the hydroisomerization catalysts prepared in Examples 1-3 of the present invention is 0.79-0.81 g / cm 3 , the freezing point ≤ -47 °C, and the kinematic viscosity (-20 °C) ≥ 1.5 mm 2 / s, meeting the ASTM D7566 bio-aviation fuel standard.

[0063] Test Example 2: Activity Tests of Different Catalysts Activity evaluations were carried out on the hydroisomerization catalysts prepared in Examples 1-3 and Comparative Examples 1-10.

[0064] Using palm oil as raw material, the hydroisomerization catalysts prepared in Examples 1-3 and Comparative Examples 1-10 were used as catalysts respectively and added into a high-pressure reactor for reaction. Under the conditions of reaction temperature of 320 °C, hydrogen pressure of 4 MPa, reaction time of 3 h, and catalyst dosage of 10% of the raw material mass, reaction products were obtained.

[0065] The reaction products were measured, and the cracking rate (<C10 product proportion), C10-C16 isoparaffin yield, isoselectivity, and 1000 h stability were calculated.

[0066] 1. Test Methods: 1.1 Cracking Rate (%) Definition: It refers to the mass percentage of hydrocarbons with carbon number less than 10 (<C10 products) in the total product.

[0067] Calculation method: The component analysis of the reaction products is carried out by means of gas chromatography and other methods. The total mass of the <C10 products is measured, then divided by the total mass of the reaction products, and multiplied by 100% to obtain.

[0068] 1.2 C10-C16 isoparaffin yield (%) Definition: It refers to the percentage of isoparaffins with carbon numbers from 10 to 16 in the product to the total mass of the raw materials.

[0069] Calculation method: The total mass of C10-C16 isoparaffins in the product is analyzed by gas chromatography, divided by the initial mass of the raw materials (such as palm oil) participating in the reaction, and multiplied by 100% to obtain.

[0070] 1.3 Isomerization selectivity (%) Definition: It refers to the proportion of isoparaffins in the product to all alkanes (including normal paraffins and isoparaffins), for the C10-C16 fraction.

[0071] Calculation method: The mass of isoparaffins and the mass of normal paraffins in the C10-C16 fraction are determined by chromatographic analysis. The mass of isoparaffins is divided by (the mass of isoparaffins + the mass of normal paraffins), and then multiplied by 100% to obtain. <​​​​​​​​​​​​​​​The test data in Table 2 clearly demonstrates that the hydroisomerization catalysts prepared in Examples 1-3 of the present invention demonstrate significant advantages in the production of bio-jet fuel. Specifically, Examples 1-3, using a SAPO-11 / ZSM-5 (7:3) composite support, achieved cracking rates of only 8.8%-10.0%, while yields of C10-C16 isoparaffins reached 76.2%-79.3%. In contrast, Comparative Example 1, using either a single SAPO-11 or ZSM-5 support, achieved cracking rates of 18.5%-25.3%, while yields decreased to 59.7%-65.1%. This demonstrates that combining SAPO-11 or ZSM-5 supports synergistically reduces cracking rates and increases C10-C16 isoparaffin yields.

[0075] In addition, Examples 1-3 use a Pt-Ir-Pd tri-metal combination in combination with La2O3+P additives, and the isomerization selectivity reaches 89.5%-92.0%, and the activity decreases by only 4.2%-5.0% in 1000h; Comparative Example 3 does not add additives, Comparative Examples 4-5 add one of the additives respectively, and Comparative Examples 6-8 load a single Pt, Ir, and Pd metal respectively, and the C10-C16 isoparaffin yield and isomerization selectivity are significantly reduced, indicating that the electronic synergy of the tri-metals and the acidic regulation effect of the additives are the core of improving selectivity and stability.

[0076] Comparative Example 9 omits the pore structure optimization step, and the yield and stability are both inferior to Examples 1-3; Comparative Example 10 uses the traditional Ni-Mo system, with a cracking rate of up to 32.5% and a yield of only 53.7%, further demonstrating the importance of the pore structure optimization step and the Pt-Ir-Pd precious metal system in the present invention to weakening cracking and improving the yield of the target product.

[0077] In summary, the present invention achieves the technical effects of reduced cracking rate, improved target isoparaffin yield and selectivity, and enhanced stability through the coordinated design of a composite carrier, a tri-metal active component, and a La2O3+P additive. It is significantly superior to solutions using a single carrier, a single metal, a missing additive, or a 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 hydroisomerization catalyst comprises a composite carrier and a catalytically active component supported on the composite carrier; The composite support is a SAPO-11 / ZSM-5 composite molecular sieve modified with La2O3 and P; The composite carrier has a mesoporous-microporous multi-level pore structure, wherein the pore size of the mesopore is 10-30nm, the pore size of the micropore is 0.5-0.6nm, and the total pore volume is ≥0.8cm 3 / g; The catalytically active component is a combination of Pt, Ir, and Pd; The content of the catalytically active components is calculated as simple metal, 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.

2. The hydroisomerization catalyst according to claim 1, characterized in that The composite carrier is prepared by the following method: 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; dissolving a La2O3 precursor and a P precursor in water to obtain a mixed solution; Add SAPO-11 / ZSM-5 composite molecular sieve into the mixed solution, stir at 25-100° C., dry to remove the solvent, and then calcine at 500-600° C. for 3-5 hours to obtain a composite carrier.

3. The hydroisomerization catalyst according to claim 2, characterized in that The silicon-aluminum ratio of the ZSM-5 molecular sieve is 50-100.

4. The hydroisomerization catalyst according to claim 2, characterized in that 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; The ratio of the added amount of the SAPO-11 / ZSM-5 composite molecular sieve to the mixed solution is 1 g: 1-10 mL.

5. The method for preparing the hydroisomerization catalyst according to any one of claims 1 to 4, characterized in that: The method comprises a catalytically active component loading step and a pore structure optimization step; The catalytically active component loading step comprises: Pt metal salt, Ir metal salt, Pd metal salt and composite support are mixed and dissolved in a solvent, stirred evenly, 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° C. for 5-100 hours, filtered, dried, and then reduced to obtain a hydroisomerization catalyst.

6. The preparation method according to claim 5, characterized in that In the catalytic active component loading step, the solvent is water or ethanol; the calcination temperature is 400-600° C., and the calcination time is 2-4 hours.

7. The preparation method according to claim 5, 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 added amount of the initial product to the tetrapropylammonium bromide aqueous solution is 1g:10-50mL; The reduction treatment conditions are: reduction at 300-500° C. for 2-4 hours in a hydrogen atmosphere with a hydrogen flow rate of 20-50 mL / min.

8. Use of the hydroisomerization catalyst according to any one of claims 1 to 4 in the catalytic production of bio-jet fuel.

9. Use of the hydroisomerization catalyst according to any one of claims 1 to 4 in improving the yield of C10-C16 isoparaffins in bio-jet fuel.

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