Metal catalyst loaded on high-acidity-density carrier and application of metal catalyst in catalyzing hydrodeoxygenation of waste edible oil

Abstract

The invention discloses a metal catalyst loaded on a high-acidity-density carrier and application of the metal catalyst in catalysis of hydrodeoxygenation of waste edible oil, and belongs to the field of waste oil refining. According to the invention, the Nb1-SAPO-11 carrier with high acidic density is prepared through an Nb isomorphic substitution strategy, and the Nb1-SAPO-11 carrier and the active metal Ru synergistically exert the optimal catalytic performance; in order to further improve the deoxidation performance of the catalyst, doping of trace Fe atoms and Ru generate a strong electron synergistic effect, hydrogenation sites and acid sites on the surface of the catalyst are greatly enriched, and therefore the interaction between metal and acid double active sites is enhanced, and the deoxidation performance of the catalyst is improved. The deoxidation activity of the bimetallic Ru2Fe0.2 / Nb1-SAPO-11 catalyst is far higher than that of a monometal Ru2 / Nb1-SAPO-11 catalyst, and the C15-C18 alkane selectivity of the bimetallic Ru2Fe0.2 / Nb1-SAPO-11 catalyst is as high as 93.4%. The method has a good application prospect in the aspect of conversion of waste fat into biofuel.

Description

Technical Field

[0001] The invention relates to a metal catalyst loaded on a high-acid density carrier and application thereof in catalyzing the hydrogenation and deoxygenation of waste edible oil, belonging to the field of waste oil refining. Background Art

[0002] Large-scale conversion of waste oils and fats into biofuels is of great significance for alleviating the global dependence on crude oil resources and reducing the environmental pressure caused by climate change. However, the inherent high oxygen content in lipids has become a major obstacle to the development of high-energy-density biofuels. To overcome this challenge, efficient activation and cleavage of C–O bonds are particularly critical. This process usually requires the synergistic effect of metals and acidic components, which constitutes the core step of hydrodeoxygenation technology.

[0003] SAPO-11 molecular sieve has attracted extensive attention in lipid catalytic conversion due to its one-dimensional pores and tunable acidity. However, its limited acidity severely restricts the deoxygenation efficiency of waste oil. In addition, acid site distribution is also crucial to reduce secondary cracking and optimize product distribution. In the past decade, niobium compounds have shown unique properties in acid-catalyzed reactions due to their obvious surface acidity. To date, there has been no research on doping Nb in SAPO-11 to catalyze the hydrodeoxygenation of waste cooking oil.

[0004] Ruthenium (Ru) is a platinum group metal with a d electron configuration that can rapidly adsorb hydrogen and activate C–O bonds. In addition, the market price of Ru is only 1 / 25 of that of platinum (Pt), making it a more cost-effective alternative for catalytic lipid upgrading. However, Ru-based catalysts are currently only widely used in lignin depolymerization and polyolefin hydrolysis, and their application in converting lipids and related model compounds into biofuels remains to be explored. In particular, the single surface characteristics and inherent electronic limitations of monometallic Ru catalysts pose challenges for the efficient adsorption and activation of C–O bonds. These challenges hinder the stable and directional conversion of intermediates during hydrogenation, ultimately affecting the generation activity and selectivity of the products. Summary of the invention

[0005] [Technical issues]

[0006] The limited acid content of existing SAPO-11 molecular sieves and the single surface characteristics and inherent electronic confinement of monometallic Ru catalysts pose challenges to the adsorption and activation of the C–O bonds of fatty acid molecules. These challenges hinder the stable and directional conversion of intermediates during the hydrogenation process, ultimately affecting the product generation activity and selectivity.

[0007] [Technical solution]

[0008] In view of the defects and deficiencies of the prior art, the purpose of the present invention is to provide a metal catalyst supported on a high acid density carrier and its application in catalytic hydrodeoxygenation of waste cooking oil. The catalyst is to modify the SAPO-11 carrier by Nb isomorphic substitution strategy to obtain a Nb1-SAPO-11 carrier with higher acid density and weak acid / medium strong acid ratio. The carrier is conducive to the activation of C-O bonds, inhibits the cracking of secondary products, and exhibits the best catalytic performance under the synergistic effect with the active metal Ru. At the same time, iron (Fe) becomes an ideal dopant due to its strong oxygen affinity and low electronegativity. The larger atomic radius of Fe induces Ru lattice expansion and inhibits crystal growth, thereby resulting in a reduction in particle size and more exposure of active sites. Therefore, a second metal Fe with strong oxygen affinity and low electronegativity is introduced at the same time. The addition of trace Fe atoms produces a strong electronic synergistic effect with Ru, greatly enriching the hydrogenation sites and acid sites on the catalyst surface, and strengthening the interaction between the dual active sites of metal and acid, thereby improving its catalytic performance in the hydrodeoxygenation of waste cooking oil.

[0009] In order to achieve the above purpose, the technical solutions provided are as follows:

[0010] The present invention provides a method for preparing a metal catalyst supported on a high acid density carrier, the preparation method comprising the following steps:

[0011] (1) Preparation of high acid density carrier Nb-SAPO-11

[0012] The aluminum source is dispersed in water to form a uniform white slurry; then a phosphorus source is added and stirred vigorously to obtain a mixed slurry; a template and a silicon source are added to the mixed slurry respectively, and after stirring evenly, a niobium source is added to obtain a homogeneous slurry; the homogeneous slurry is subjected to a hydrothermal reaction in a reactor to obtain a white gel, which is dried and calcined to obtain a Nbx in-situ doped SAPO-11 carrier, i.e., a high acid density carrier Nbx-SAPO-11; wherein x represents the doping amount of Nb in the carrier, which is 1 to 3 wt% respectively;

[0013] (2) Preparation of metal catalysts

[0014] The high-acid density carrier Nbx-SAPO-11 prepared in step (1) is immersed in an aqueous solution of a ruthenium source and / or an iron source, and then taken out, dried, calcined, and reduced to obtain the product.

[0015] In one embodiment, the aluminum source in step (1) is one or both of pseudoboehmite and aluminum isopropoxide; the phosphorus source is orthophosphoric acid; the template is any one of dipropylamine, diisopropylamine and diethylamine; and the silicon source is one or more of silica sol, tetraethyl orthosilicate and fumed silica.

[0016] In one embodiment, the mass ratio of the aluminum source, phosphorus source, template, silicon source and water in step (1) is 1:1:0.3:1.4:50.

[0017] In one embodiment, the niobium source in step (1) is one or both of niobium pentachloride and niobium pentoxide.

[0018] In one embodiment, the doping amount of Nb in step (1) is 1 wt%.

[0019] In one embodiment, the hydrothermal reaction conditions in step (1) are: 100-200° C., 12-36 h.

[0020] In one embodiment, the drying conditions in step (1) are: 100-120° C., 10-15 h.

[0021] In one embodiment, the calcination conditions in step (1) are: 500-800° C., 3-10 h.

[0022] In one embodiment, the ruthenium source in step (2) is one or both of ruthenium trichloride trihydrate and ruthenium nitrate.

[0023] In one embodiment, the iron source in step (2) is one or both of ferric nitrate nonahydrate and ferric chloride.

[0024] In one embodiment, the loading amount of ruthenium in the metal catalyst in step (2) is 2 wt %.

[0025] In one embodiment, the doping amount of the metal catalyst Fe in step (2) is 0-2wt%; preferably 0.1-0.5wt%; more preferably 0.1-0.2wt%; and even more preferably 0.2wt%.

[0026] In one embodiment, the immersion time in step (2) is 8 to 16 hours.

[0027] In one embodiment, the drying conditions in step (2) are: 60-80° C., 8-24 h.

[0028] In one embodiment, the calcination conditions in step (2) are: 300-600° C., 2-5 h.

[0029] In one embodiment, the reduction conditions in step (2) are: 500-800° C., 2-5 h.

[0030] The present invention also provides a metal catalyst loaded on a high-acid density carrier prepared by the above method.

[0031] In one embodiment, the metal catalyst supported on the high acid density carrier is Ru2 / Nb1-SAPO-11, wherein Nb1 refers to the Nb loading in the catalyst of 1 wt%.

[0032] In one embodiment, the metal catalyst supported on the high acid density carrier is Ru 2 Fe 0.2 / Nb1-SAPO-11; wherein, Nb1 refers to the Nb loading in the catalyst is 1wt%; Fe 0.2 It means that the doping amount of Fe in the catalyst is 0.2 wt%.

[0033] The present invention also provides the use of the above-mentioned metal catalyst supported on a high-acid density carrier in a hydrodeoxygenation reaction.

[0034] The present invention also provides a method for the hydrodeoxygenation reaction of waste cooking oil, the method comprising the following steps:

[0035] Add waste cooking oil, the metal catalyst supported on the high acid density carrier and n-hexane solvent into the reactor, exhaust the inert gas, introduce 1-3Mpa hydrogen after sealing, and react at 300-500°C for 3-5h under stirring.

[0036] In one embodiment, the major fatty acids of the waste cooking oil include palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid.

[0037] In one embodiment, the waste cooking oil, the metal catalyst supported on the high acid density carrier and the solvent are added in a ratio of 0.5:0.2:10-15; g:g:mL.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The present invention adopts the Nb isomorphous substitution strategy to modify the SAPO-11 carrier; Nb1-SAPO-11 has the highest 002 crystal face peak, which means that the overlap of the lamellar crystals inside the particles is higher, thus forming abundant interlayer pores and widely distributed acid sites. At the same time, Nb1-SAPO-11 has a higher acid density and weak acid / medium strong acid ratio, which is conducive to the activation of C–O bonds, inhibits the cracking of secondary products, and exhibits the best catalytic performance under the synergistic effect with the active metal Ru.

[0040] (2) In single metal Ru 2On the basis of the Nb1-SAPO-11 catalyst, the present invention introduces a second metal Fe with strong oxygen affinity and low electronegativity. The addition of trace Fe atoms produces a strong electronic synergy with Ru, greatly enriching the hydrogenation sites and acid sites on the catalyst surface and strengthening the interaction between the dual active sites of metal and acid. 2 Fe 0.2 The deoxygenation activity of / Nb1-SAPO-11 catalyst far exceeds that of single metal Ru 2 / Nb1-SAPO-11 catalyst, C 15 -C 18 The selectivity of alkanes is as high as 93.4%.

[0041] (3) Ru prepared by the present invention 2 Fe 0.2 The Nb1-SAPO-11 catalyst achieved highly efficient catalytic conversion of five individual fatty acids from waste cooking oil, even for highly unsaturated linolenic acid, whose C 15 -C 18 The selectivity of alkanes also exceeded 85%. After five cycles of use, the waste oil conversion rate and C 15 -C 18 The selectivity of alkanes decreased by 10.5% and 13.3%, respectively, but the catalytic performance was still higher than that of Ru 2 / Nb1-SAPO-11. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is the XRD pattern of Example 1-3;

[0043] Figure 2 The XPS spectra of Example 5, Example 9 and Example 10 are shown in FIG.

[0044] Figure 3 H of Example 5, Example 9 and Example 10 2 -TPD spectrum;

[0045] Figure 4 This is a graph showing the reaction results of Example 9 on five fatty acids;

[0046] Figure 5 This is a graph showing the reaction results of Example 9 when used five times continuously. DETAILED DESCRIPTION

[0047] The present invention is described in detail below with reference to the embodiments.

[0048] The raw material sources involved in the present invention are:

[0049] Pseudo-boehmite (Al 2 O 3, 70%), orthophosphoric acid (H 3 PO 4 ,85%), dipropylamine (C 6 H 15 N, 98%), niobium pentachloride (NbCl 5 ,99.9%), ruthenium trichloride trihydrate (RuCl 3 -3H 2 O, 98%), ferric nitrate nonahydrate (Fe(NO 3 ) 3 -9H 2 O,98%), nickel nitrate hexahydrate (Ni(NO 3 ) 2 -6H 2 O, 98%), cobalt nitrate hexahydrate (Co(NO 3 ) 2 -6H 2 O, 98.5%): Sinopharm Chemical Reagent Co., Ltd.; silica sol (SiO 2 ,30%): Zhejiang Yuda Chemical Co., Ltd.;

[0050] SAPO-34 molecular sieve (NZ-HSP34-004), ZSM-5 molecular sieve (NZ-HZ5-001): Excellent Environmental Protection New Materials Co., Ltd.

[0051] Example 1 Preparation of original SAPO-11 molecular sieve

[0052] The preparation of SAPO-11 material includes the following:

[0053] First, 8.8 g of pseudo-boehmite was dispersed in 54.0 g of deionized water and ultrasonicated at 50°C for 30 min to form a uniform white slurry; then, 13.8 g of orthophosphoric acid was added to the stirred white slurry and stirred vigorously for 2 h to obtain a mixed slurry; 6.6 g of dipropylamine was slowly added to the mixed slurry, and continued to stir vigorously for 2 h, followed by adding 5.76 g of silica sol, and after stirring vigorously for 1 h, the obtained mixed slurry was transferred to a hydrothermal reactor and kept at 200°C for crystallization for 24 h to obtain a white gel; the obtained white gel was washed with deionized water until neutral, dried in an oven at 110°C for 12 h, and then calcined at 600°C in a muffle furnace for 6 h to obtain SAPO-11 material.

[0054] Example 2 Preparation of Nb1-SAPO-11 Molecular Sieve

[0055] The preparation method of Nb1-SAPO-11 is basically the same as that of the original SAPO-11, with the only difference being that 0.0785 g of NbCl 5 and stirred for 1 h.

[0056] Example 3 Preparation of Nb3-SAPO-11 Molecular Sieve

[0057] The preparation method of Nb3-SAPO-11 is basically the same as that of the original SAPO-11. The only difference is that after the introduction of silica sol, 0.2355 g of NbCl 5 and stirred for 1 h.

[0058] Figure 1 The XRD results confirmed that in-situ Nb substitution did not change the crystal structure of SAPO-11, and the corresponding Nb diffraction peaks were only present in the Nb3-SAPO-11 sample, implying the fine dispersion of Nb in Nb1-SAPO-11. Nb1-SAPO-11 exhibited the highest 002 crystal plane peak, which reflected the higher overlap of the lamellar crystals within the particles, resulting in abundant interlayer pores and widely distributed acidic sites.

[0059] Table 1 Acid amount and acid position distribution of Examples 1-3

[0060]

[0061] From the results in Table 1, it can be seen that Nb1-SAPO-11 has the highest total acid content and the highest weak acid / medium strong acid ratio. This is because trace Nb (1 wt% in Example 2) enhances the weak acid sites through surface hydroxyl interactions, while excess Nb (3 wt% in Example 3) promotes the generation of extra-framework Nb species (Nb 2 O 5 ) is formed, thereby enhancing the medium and strong acid sites.

[0062] Example 4Ru 2 / Preparation of SAPO-11 catalyst

[0063] The loading amount of Ru was controlled to be 2 wt%; 0.1554 g of RuCl 3 ·3H 2 3 g of the SAPO-11 carrier prepared in Example 1 was impregnated with an aqueous solution obtained by mixing 100 mL of H 2 O and 9 mL of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined product was heated at 500 °C for 12 h. 2 Reduce for 3 h.

[0064] Example 5Ru 2 Preparation of / Nb1-SAPO-11 catalyst

[0065] The loading amount of Ru was controlled to be 2 wt%; 0.1554 g of RuCl 3 ·3H 23 g of the Nb1-SAPO-11 carrier prepared in Example 2 was impregnated with an aqueous solution obtained by mixing 100 mL of H2O and 9 mL of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 12 h. 2 Reduce for 3 h.

[0066] Example 6Ru 2 Preparation of Nb3-SAPO-11 catalyst

[0067] The loading amount of Ru was controlled to be 2 wt%; 0.1554 g of RuCl 3 ·3H 2 3 g of the Nb3-SAPO-11 carrier prepared in Example 3 was impregnated with an aqueous solution obtained by mixing 200 mL of H2O and 9 mL of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 12 h. 2 Reduce for 3 h.

[0068] Comparative Example 1Ru 2 / Preparation of SAPO-34 catalyst

[0069] The loading amount of Ru was controlled to be 2 wt%; 0.1554 g of RuCl 3 ·3H 2 3 g of commercial SAPO-34 support was impregnated with an aqueous solution obtained by mixing 100 mL of H 2 O and 9 mL of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h under H 2 Reduce for 3 h.

[0070] Comparative Example 2Ru 2 Preparation of ZSM-5 catalyst

[0071] The loading amount of Ru was controlled to be 2 wt%; 0.1554 g of RuCl 3 ·3H 2 3 g of commercial ZSM-5 support was impregnated with an aqueous solution obtained by mixing 100 mL of H 2 O and 9 mL of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h under H 2 Reduce for 3 h.

[0072] Example 7

[0073] The hydrodeoxygenation reaction was carried out in a 100 ml high pressure reactor: the reaction system included 0.5 g of waste cooking oil (18.8% palmitic acid, 5.23% stearic acid, 36.7% oleic acid, 35.3% linoleic acid and 3.10% linolenic acid), 0.2 g of reduction catalyst and 15 ml of cyclohexane solvent. Before the reaction started, the reactor was purged with nitrogen for 5 min to eliminate air interference, then pressurized to 3 MPa, heated to 300 ° C, and after the reaction was run for 3 h, the liquid product was separated from the catalyst by a centrifuge, and the liquid product was analyzed by a gas chromatograph equipped with a flame ionization detector (FID) and an HP-5 capillary column (30 m × 0.25 mm × 0.25 μm). C 8 -C 40 Alkane mixed standards and chromatographically pure standard reagents (palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, hexadecanal, octadecanal, hexadecanol and octadecanol) were used to calculate the conversion rate of waste oil, target alkane selectivity and cracking product selectivity.

[0074] Example 8

[0075] The samples obtained in Examples 1-6 and Comparative Examples 1 and 2 were subjected to hydrodeoxygenation experiments respectively, and the operation details are shown in Example 7.

[0076] Table 2 Reaction results of Examples 1-6 and Comparative Examples 1-2

[0077]

[0078] As shown in Table 2, the catalytic performance of the pure molecular sieve carrier is negligible. 2 / Nb1-SAPO-11 has the highest catalytic activity and the lowest degree of cracking, which is attributed to the high total acid content and weak acid / medium strong acid ratio of Nb1-SAPO-11. 2 The catalytic performance of Nb1-SAPO-11 is superior to that of Ru supported on commercial molecular sieves. 2 / SAPO-34 and Ru 2 / ZSM-5 catalyst.

[0079] In order to further improve Ru 2 The catalytic activity of / Nb1-SAPO-11 was tested as follows.

[0080] Example 9Ru 2 Fe 0.2 Preparation of / Nb1-SAPO-11 catalyst

[0081] The Ru loading was fixed at 2 wt % and the Fe doping amount was controlled at 0.2 wt %. 0.1554 g of RuCl 3 ·3H2 O, 0.0434g of Fe(NO 3 ) 3 9H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution obtained by mixing 100 mL of H2O and 9 mL of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 12 h. 2 Reduce for 3 h.

[0082] Example 10Ru 2 Fe 1 Preparation of / Nb1-SAPO-11 catalyst

[0083] The Ru loading was fixed at 2 wt % and the Fe doping level was controlled at 1 wt %. 3 ·3H 2 O (0.1554 g), Fe (NO 3 ) 3 9H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.2170 g of O (0.2170 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0084] Figure 2 The XPS results show that since the electronegativity of Fe (1.83) is lower than that of Ru (2.20), electrons are transferred from Fe to Ru, resulting in the Ru 0 The binding energy of Ru 2 Fe 0.2 Ru in Nb1-SAPO-11 0 The content of the species is the highest, indicating that more active sites are exposed on the catalyst surface, which is beneficial to the activation of hydrogen.

[0085] Figure 3 H 2 -TPD confirms Ru 2 Fe 0.2 / Nb1-SAPO-11 has the strongest hydrogen dissociation ability (77.8 μmol / g), far exceeding Ru 2 / Nb1-SAPO-11(69.2μmol / g) and Ru 2 Fe 1 / Nb1-SAPO-11 (57.0 μmol / g). Therefore, Ru 2 Fe 0.2Ru / Nb1-SAPO-11 has stronger hydrogenation ability.

[0086] Table 3 Acid amount and acid site distribution of Example 5, Example 9 and Example 10

[0087]

[0088] As can be seen from Table 3, Ru covers some acid sites on Nb1-SAPO-11, resulting in a decrease in the total acid amount of Ru 2 / Nb1-SAPO-11. After doping 0.2 wt% Fe, the total acidity of Ru 2 Fe 0.2 / Nb1-SAPO-11 increases slightly compared with Ru 2 / Nb1-SAPO-11, while the total acid amount of Ru 2 Fe 1 / Nb1-SAPO-11 decreases significantly. The W / MAS ratio of Ru 2 Fe 0.2 / Nb1-SAPO-11 increases from 1.4 to 2.0, reflecting the regulation of the acidic distribution of the catalyst by Fe element. The pyridine infrared results show that the 2 Fe 0.2 acid amount in Ru / Nb1-SAPO-11 is the highest, attributed to its strong hydrogen migration ability. Electron-deficient Fe 3+ / Fe 2+ can act as new Lewis acid sites, making the Lewis acid amount of the bimetallic RuFe catalyst significantly higher than that of the monometallic Ru 2 / Nb1-SAPO-11, which is beneficial to the activation of C–O bonds. However, the 2 Fe 1 in Ru / Nb1-SAPO-11 is extremely imbalanced (0.4) because the increase in surface Fe oxides weakens the proton transfer related to acids.

[0089] Preparation of the Ru 2 Fe 0.1 / Nb1-SAPO-11 catalyst in Example 11

[0090] Fix the loading amount of Ru at 2 wt% and control the doping amount of Fe at 0.1 wt%. By using RuCl 3 ·3H 2 O (0.1554 g), Fe(NO 3 ) 3 ·9H 23 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.0217 g of O (0.0217 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0091] Example 12Ru 2 Fe 0.15 Preparation of / Nb1-SAPO-11 catalyst

[0092] The Ru loading was fixed at 2 wt % and the Fe doping level was controlled at 0.15 wt %. 3 ·3H 2 O (0.1554 g), Fe (NO 3 ) 3 9H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.0326 g of O (0.0326 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0093] Example 13Ru 2 Fe 0.4 Preparation of / Nb1-SAPO-11 catalyst

[0094] The Ru loading was fixed at 2 wt % and the Fe doping level was controlled at 0.4 wt %. 3 ·3H 2 O (0.1554 g), Fe (NO 3 ) 3 9H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.0868 g of O (0.0868 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0095] Example 14Ru 2 Fe 0.5 Preparation of / Nb1-SAPO-11 catalyst

[0096] The Ru loading was fixed at 2 wt % and the Fe doping level was controlled at 0.5 wt %. 3 ·3H 2 O (0.1554 g), Fe (NO3 ) 3 9H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.1085 g of O (0.1085 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0097] Example 15Ru 2 Fe 2 Preparation of / Nb1-SAPO-11 catalyst

[0098] The Ru loading was fixed at 2 wt % and the Fe doping level was controlled at 2 wt %. 3 ·3H 2 O (0.1554 g), Fe (NO 3 ) 3 9H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.4340 g of O (0.4340 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0099] Example 16Fe 0.2 Preparation of / Nb1-SAPO-11 catalyst

[0100] The Ru loading was fixed at 0 and the Fe doping level was 0.2 wt %. 3 ) 3 9H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.4340 g of O (0.4340 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0101] Comparative Example 3Ru 2 Ni 0.2 Preparation of / Nb1-SAPO-11 catalyst

[0102] The Ru loading was fixed at 2 wt % and the Ni doping amount was controlled at 0.2 wt %. 3 ·3H 2 O (0.1554 g), Ni (NO 3 ) 26H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.0292 g of O (0.0292 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0103] Comparative Example 4Ru 2 Co 0.2 Preparation of / Nb1-SAPO-11 catalyst

[0104] The Ru loading was fixed at 2 wt % and the Co doping amount was controlled at 0.2 wt %. 3 ·3H 2 O (0.1554 g), Co (NO 3 ) 2 6H 2 3 g of Nb1-SAPO-11 support was impregnated with an aqueous solution of 0.0296 g of O (0.0296 g) and 9 ml of deionized water for 12 h, dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at 400 °C for 5 h. Before use, the calcined catalyst was heated at 500 °C for 1 h. 2 Reduce for 3 h.

[0105] Embodiment 17

[0106] The samples obtained in Examples 9 to 16 and Comparative Examples 3 and 4 were subjected to hydrodeoxygenation experiments respectively. The operation details are as shown in Example 7.

[0107] Table 4 Reaction results of examples and comparative examples

[0108]

[0109] As shown in Table 4, due to the weak hydrogenation ability of Fe, Fe 0.2 The catalytic performance of / Nb1-SAPO-11 is negligible, which confirms that Ru is the main active component. By increasing the Fe content from 0% to 0.2wt%, the WCO conversion rate increased from 85.3% to 98.2%, and the C 15 -C 18 The selectivity of alkanes is as high as 93.4%, thanks to Ru 2 Fe 0.2 / Nb1-SAPO-11 catalyst exposed more hydrogenation and acid sites. However, further doping with Fe resulted in decreased conversion and selectivity, accompanied by the accumulation of oxidation intermediates, especially fatty alcohols. 2 Fe 1This is particularly evident in / Nb1-SAPO-11, where the unconverted fatty alcohol content reaches 22.7%, due to the weakening of the synergistic effect between metal and acid sites. 2 Ni 0.2 / Nb1-SAPO-11 and Ru 2 Co 0.2 / Nb1-SAPO-11 catalysts were compared. The results showed that Ru 2 Ni 0.2 / Nb1-SAPO-11 and Ru 2 Co 0.2 The cracking degree of the catalyst was more serious over Nb1-SAPO-11, which resulted in 15 -C 18 Lower selectivity for alkanes than Ru 2 Fe 0.2 / Nb1-SAPO-11 catalyst.

[0110] Five individual fatty acids derived from the main components of waste cooking oil were used to verify Ru 2 Fe 0.2 / Nb1-SAPO-11 catalyst universality. The specific implementation is as follows:

[0111] Embodiment 18

[0112] The Ru obtained in Example 9 2 Fe 0.2 / Nb1-SAPO-11 catalyst was used for the hydrodeoxygenation of palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid standards, and the operating details are shown in Example 7.

[0113] Depend on Figure 4 It can be seen that the Ru obtained in Example 9 2 Fe 0.2 The Nb1-SAPO-11 catalyst achieved highly efficient catalytic conversion of all five fatty acids, even for the highly unsaturated α-linolenic acid, whose C 15 -C 18 The alkane selectivity also exceeded 85%.

[0114] The Ru 2 Fe 0.2 / Nb1-SAPO-11 catalyst stability. The specific implementation is as follows:

[0115] Embodiment 19

[0116] The Ru obtained in Example 9 2 Fe 0.2 / Nb1-SAPO-11 catalyst is used for the hydrodeoxygenation of waste cooking oil. After the first reaction, the catalyst is separated and recovered and used for the second reaction. This process is repeated five times in succession. The operation details are shown in Example 7.

[0117] Depend on Figure 5 It can be seen that the Ru obtained in Example 9 2 Fe 0.2 After the catalyst Nb1-SAPO-11 was used for five times, the conversion rate of WCO and C 15 -C 18 The selectivity of alkanes decreased by 10.5% and 13.3%, respectively, but the catalytic activity was still higher than that of the Ru obtained in Example 5. 2 / Nb1-SAPO-11 catalyst.

[0118] The scope of protection of the present invention shall be limited by the claims defined in the appended claims. Various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A method for preparing a metal catalyst supported on a high acid density carrier, characterized in that: The preparation method comprises the following steps: (1) Preparation of high acid density carrier Nb-SAPO-11 The aluminum source is dispersed in water to form a uniform white slurry; then a phosphorus source is added and stirred vigorously to obtain a mixed slurry; a template and a silicon source are added to the mixed slurry respectively, and after stirring evenly, a niobium source is added to obtain a homogeneous slurry; the homogeneous slurry is subjected to a hydrothermal reaction in a reactor to obtain a white gel, which is dried and calcined to obtain a Nbx in-situ doped SAPO-11 carrier, i.e., a high acid density carrier Nbx-SAPO-11; wherein x represents the doping amount of Nb in the carrier, which is 1 to 3 wt% respectively; (2) Preparation of metal catalysts The high-acid density carrier Nbx-SAPO-11 prepared in step (1) is immersed in an aqueous solution of a ruthenium source and / or an iron source, and then taken out, dried, calcined, and reduced to obtain the product.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the aluminum source, phosphorus source, template, silicon source and water in step (1) is 1:1:0.3:1.4:

50.

3. The preparation method according to claim 1, characterized in that: The doping amount of Nb in step (1) is 1 wt%.

4. The preparation method according to claim 1, characterized in that: The loading amount of ruthenium in the metal catalyst in step (2) is 2 wt%.

5. The preparation method according to claim 1, characterized in that: The doping amount of Fe in the metal catalyst in step (2) is 0 to 2 wt%, preferably 0.1 to 0.5 wt%.

6. The metal catalyst supported on a high acid density carrier prepared by the preparation method according to any one of claims 1 to 5.

7. The metal catalyst supported on a high acid density carrier according to claim 6, characterized in that: The catalyst is Ru2 / Nb1-SAPO-11, wherein Nb1 refers to the Nb loading amount in the catalyst being 1 wt%.

8. The metal catalyst supported on a high acid density carrier according to claim 6, characterized in that: The metal catalyst is Ru2Fe 0.2 / Nb1-SAPO-11; Among them, Nb1 refers to the Nb loading in the catalyst is 1wt%; Fe 0.2 It refers to the doping amount of Fe in the catalyst being 0.2 wt%.

9. Use of the metal catalyst supported on a high acid density carrier according to any one of claims 6 to 8 in a hydrodeoxygenation reaction.

10. A method for hydrodeoxygenation of waste cooking oil, characterized in that: The method comprises the following: Add waste cooking oil, the metal catalyst supported on a high acid density carrier as claimed in any one of claims 6 to 8 and n-hexane solvent into the reactor, exhaust the inert gas, introduce 1 to 3 MPa hydrogen after sealing, and react at 300 to 500° C. for 3 to 5 hours under stirring.

Images