Hydrogenation catalyst carrier and preparation method thereof

Abstract

The invention relates to the technical field of catalytic hydrogenation, and particularly discloses a hydrogenation catalyst carrier and a preparation method thereof. According to the preparation method, aluminum hydroxide and aluminum fumarate are simultaneously obtained in a gel forming process; after hydrothermal treatment, dry gel powder formed by mixing the aluminum hydroxide and the aluminum fumarate, an extrusion aid and the like are subjected to extrusion molding to obtain the hydrogenation catalyst carrier. The aluminum oxide carrier with better pore volume, specific surface area and adsorbability can be formed by utilizing the high specific surface area of aluminum in aluminum hydroxide fumarate and a metal organic framework of fumaric acid and the strong adsorption capacity on CO2, forming a crystal nucleus by an inorganic or organic auxiliary agent and adding a hydrothermal treatment process in a gel forming process.

Description

Technical Field

[0001] This invention relates to the field of catalytic hydrogenation technology, and in particular to a hydrogenation catalyst support and its preparation method. Background Technology

[0002] Coking dry gas is a byproduct gas from coal or petroleum coking. It mainly contains hydrogen, low-carbon alkanes, and olefins, as well as impurities such as hydrogen sulfide and carbon dioxide. Its production volume is related to the coking raw materials and processes. Due to its rich content of hydrogen and low-carbon hydrocarbons, it is a potential chemical raw material or fuel, but it needs to undergo purification treatments such as hydrodesulfurization and deolefin removal to eliminate impurities and enhance its utilization value.

[0003] In the hydrotreating of coking dry gas, the catalyst support is crucial, serving to disperse active components, provide reactive surfaces, and enhance the catalyst's mechanical strength and thermal stability. Commonly used supports include alumina, molecular sieves, and silica, with alumina being the most widely used due to its moderate specific surface area, good mechanical strength, and thermal stability. Its pore structure can be adjusted to suit different reactions. Furthermore, oxide supports such as magnesium oxide and zirconium oxide, due to their special properties, are suitable for scenarios involving sulfur poisoning resistance and high-temperature hydrogenation. Composite supports combine the advantages of single supports to optimize catalyst activity and stability. The selection of the support requires a comprehensive consideration of the reaction type, the content of impurities in the raw materials, and the reaction conditions to achieve efficient purification and catalytic conversion. CN107519888A discloses a catalyst support, a hydrogenation catalyst, its preparation method, and its applications. The preparation method includes the following steps: First, the γ-alumina support is contacted with a mixture containing urea, a water-soluble salt of a Group VIII metal element, and water, and then heat-treated. After the heat-treated solid is dried and calcined, a calcined product is obtained. Next, the calcined product is impregnated with a fluorine-containing aqueous solution, and after drying and calcination, a modified γ-alumina support is obtained. Finally, the modified support is impregnated with a water-soluble salt solution containing Group VIB and Group VIII metals. The hydrorefining catalyst prepared by this method has significantly improved activity and a significantly extended service life compared with existing technologies, and is suitable for hydrodesulfurization and / or hydrodenitrification processes.

[0004] CN113019445A relates to a modified hydrotreating catalyst support, the catalyst itself, its preparation method, and its application. The modified hydrotreating catalyst support comprises a hydrotreating catalyst support and a modifier, the modifier being chitosan, with the mass ratio of chitosan to the hydrotreating catalyst support between 0.5:1 and 10:1. The preparation method involves impregnating the hydrotreating catalyst support with a solution containing chitosan and organic acid, followed by heat treatment to obtain the modified support. The catalyst prepared from this modified support is particularly suitable for hydrotreating processes of heavy distillate oils, effectively improving hydrodenitrogenation activity.

[0005] Alumina is the most widely used catalyst support, but current models still suffer from several problems: a single pore structure makes it difficult to balance high specific surface area with suitable pore volume, resulting in low mass transfer efficiency; an unreasonable distribution of acidic sites on its surface, especially Brønsted acid sites, which easily lead to side reactions such as carbon deposition and cracking; weak competitive adsorption capacity for impurities such as CO and CO2 in the feed gas, resulting in poor catalyst poisoning resistance; and insufficient thermal and structural stability of the support at high temperatures. Therefore, there is a need to develop a hydrogenation catalyst support with high mass transfer efficiency, good stability, and excellent resistance to impurities. Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a hydrogenation catalyst support and a method for preparing the same.

[0007] This invention simultaneously yields a dry adhesive powder of aluminum hydroxide and aluminum fumarate during the gelation process. After hydrothermal treatment, the dry adhesive powder of aluminum hydroxide and aluminum fumarate is extruded to obtain a hydrogenation catalyst support. This invention utilizes the high specific surface area and strong CO2 adsorption capacity of the aluminum in aluminum fumarate and the metal-organic framework of fumarate, along with the formation of crystal nuclei by inorganic or organic additives and the addition of a hydrothermal treatment process during gelation. This results in an alumina support with a lower Al coordination number and a higher CO adsorption capacity, thus enhancing the CO adsorption of the support. The synergistic effect of the different characteristics of the two alumina dry adhesive powders improves the catalyst's resistance to impurities.

[0008] The inorganic additives in this invention can be doped into the grain boundaries of the two aluminum phases, enhancing interfacial stability, while organic additives such as citric acid can chelate Al in MOF. 3+ The coordination environment of aluminum fumarate is regulated; sugar additives penetrate the biphase structure to create pores and optimize the mass transfer efficiency of the composite support. Through modification, traditional alumina is upgraded into a composite support with high acidity, high specific surface area, hierarchical channels, and high thermal stability, which meets the core requirements of hydrogenation catalysts for resisting impurities and sintering.

[0009] This invention provides an extrusion aid in which the phosphorylcholine head group provides lubrication, the polyether segment is responsible for pore formation, the tail end of the azide monomer chelates aluminum to enhance strength, and the residual phosphorus after surfactant calcination forms AlPO4 microdomains, increasing the proportion of tricoordinated aluminum. In the hydrogenation reaction, these strong L-acid sites can polarize the C=O bond, and the bimodal mesopores generated by the decomposition of the polyether segment can improve mass transfer, all of which are highly beneficial to the catalytic hydrogenation reaction. Furthermore, the extrusion aid synergistically enables selective adsorption of poisons by aluminum fumarate MOF, protecting active sites and thus enhancing resistance to poisoning. In addition to its lubricating and mixing-promoting functions, the extrusion aid prepared in this invention can also indirectly regulate the pore structure of the support, thereby improving the support performance.

[0010] This invention generates a biphase composite dry adhesive powder of aluminum hydroxide and aluminum fumarate in one step through the simultaneous neutralization reaction of aluminum sulfate, sodium aluminate, and sodium fumarate during the gelation process, providing a structural basis for the carrier. Secondly, a key hydrothermal treatment process is introduced, which can significantly increase the amount of low-coordinated tricoordinated aluminum in the final carrier. An extrusion aid is obtained by polymerizing phosphorylcholine methacrylate, amino-terminated polyether, and azide monomers, which not only plays a lubricating role in molding, but also creates pores and optimizes mass transfer after the polyether segments are calcined. The azide groups can chelate aluminum to enhance strength, and the residual phosphorus can form AlPO4 microregions to stabilize the tricoordinated aluminum structure.

[0011] Through the above scheme, this invention obtains a hierarchical porous support with both high specific surface area and large pore volume, which greatly improves mass transfer efficiency, precisely controls the acidity distribution of the support, forms an acidic environment dominated by L-acid, and effectively suppresses side reactions. Furthermore, it significantly enhances the support's resistance to impurity poisoning. Utilizing the strong CO2 adsorption capacity of aluminum fumarate MOF and the strong CO adsorption effect of tri-coordinated aluminum produced by hydrothermal treatment, selective adsorption of impurity gases is achieved, protecting hydrogenation active sites and simultaneously enhancing the stability of the support.

[0012] To achieve the above objectives, the present invention provides a method for preparing a hydrogenation catalyst support, comprising the following steps: S1. Add the additives to water at 50~90℃, then carry out the neutralization reaction of aluminum sulfate aqueous solution, sodium aluminate aqueous solution and sodium fumarate aqueous solution. After the neutralization is completed, perform hydrothermal treatment, then carry out aging reaction. The aging product is washed, filtered and dried to obtain a dry adhesive powder of aluminum hydroxide and aluminum fumarate. S2. Mix the dry adhesive powder of aluminum hydroxide and aluminum fumarate, the adhesive solvent and the extrusion aid evenly, extrude into strips, and after drying and calcination, obtain the hydrogenation catalyst support.

[0013] The method for preparing the extrusion aid includes the following steps: After mixing phosphorylcholine methacrylate and 2,2'-bipyridine, an aqueous solution of terminal amino polyether was added dropwise. The mixture was heated to 50-60°C and polymerized for 10-14 hours. Then, azide monomer and dicycloamidin were added, and the mixture was heated to 70-80°C for an addition reaction. The reaction was completed in 6-10 hours. After post-treatment, the extrusion aid was obtained.

[0014] Furthermore, the azide monomer is one of 4-azidobenzoic acid, 5-azido-1,3-phthalic acid, or ethyl 2-azidoacetate.

[0015] Furthermore, the mass ratio of phosphorylcholine methacrylate, 2,2'-bipyridine, amino-terminated polyether, azide monomer, and bicycloamidin is 1:0.01~0.02:3~4:0.4~0.6:0.01~0.015.

[0016] Preferably, the method for preparing the extrusion aid includes the following steps: Phosphorylcholine methacrylate and 2,2'-bipyridine were mixed and then added dropwise with 20-25 wt% of an amino-terminated polyether aqueous solution. The mixture was heated to 50-60℃ and polymerized for 10-14 h. Then, azide monomers and bicycloamidine were added, and the mixture was heated to 70-80℃ for an addition reaction. The reaction was completed in 6-10 h, and the product was post-treated to obtain the extrusion aid. The mass ratio of phosphorylcholine methacrylate, 2,2'-bipyridine, amino-terminated polyether, azide monomer, and bicycloamidine was 1:0.01-0.02:3-4:0.4-0.6:0.01-0.015.

[0017] Furthermore, the additive is one or more inorganic salts selected from silicon, titanium, magnesium, boron, and zirconium, or it may be derived from organic compounds; the organic compounds are citric acid, citric anhydride, isocitric acid, malic acid, tartaric acid, oxalic acid, succinic acid, glutaric acid, adipic acid, benzoic acid, phthalic acid, isophthalic acid, salicylic acid, malonic acid, fatty alcohols, ethylene glycol, propylene glycol, glycerol, methyl methoxide, methyl methoxide propane, diethylene glycol, dipropylene glycol, methyl ethylene glycol, triethylene glycol, triethylene glycol, tributylene glycol, tetraethylene glycol, tetrapropylene glycol, polyethylene glycol, diethylene methyl glycol, diethylene ethyl glycol, diethylene propyl glycol, diethylene butyl glycol, and at least one selected from monosaccharides, disaccharides, and polysaccharides with 3 to 10 carbon atoms.

[0018] Furthermore, the aluminum sulfate aqueous solution has a concentration of 4-12 g / 100 mL based on the aluminum oxide concentration; the sodium aluminate aqueous solution has a concentration of 12-40 g / 100 mL based on the aluminum oxide concentration; and the sodium fumarate aqueous solution has a concentration of 9-15 wt%.

[0019] Furthermore, the neutralization reaction conditions are a neutralization time of 0.4 to 1.5 hours and a pH value of 7.0 to 9.5.

[0020] Furthermore, the hydrothermal treatment reaction time is 4~24h, and the temperature is 70~90℃.

[0021] Furthermore, the aging reaction time is 0.2~1h.

[0022] Furthermore, the washing process typically involves washing with deionized water 2-5 times until SO4 levels are reached. 2- No more than 2.5%, Na + Not more than 0.05%, Fe 3+ No more than 0.25%.

[0023] Furthermore, in step S1, the drying conditions are a drying temperature of 90~130℃ and a drying time of 5~34h.

[0024] Furthermore, the ratio of the dry adhesive powder containing aluminum hydroxide and aluminum fumarate is 9.0~0.4.

[0025] Furthermore, the amount of the extrusion aid is 0.1% to 20.0% of the dry weight of the mixed dry adhesive powder in step S1.

[0026] Furthermore, the adhesive solvent can be one or more of aluminum sulfate, citric acid, nitric acid, acetic acid, oxalic acid, etc., and the amount used is 0.1% to 20.0% of the dry basis weight of the dry adhesive powder mixed with aluminum hydroxide and aluminum fumarate in step (1).

[0027] Furthermore, the drying and calcination conditions in step S2 are as follows: drying at 100~120℃ for 1~5 hours, and calcining at 400~550℃ for 1~5 hours.

[0028] Furthermore, the total amount of infrared acid on the hydrogenation catalyst support is 0.45~0.75 mmol / g, the amount of L acid is 0.40~0.70 mmol / g, and the ratio of Brønsted acid to L acid is 0.07~0.25.

[0029] Furthermore, the hydrogenation catalyst support has a pore volume of 0.4~1.2 mL / g and a specific surface area of ​​400~850 m². 2 / g.

[0030] Preferably, the total acid content of the hydrogenation catalyst support infrared acid is 0.50~0.70 mmol / g.

[0031] More preferably, the amount of L acid is 0.35~0.65 mmol / g.

[0032] More preferably, the ratio of Brønsted acid to L-carnitine is 0.08 to 0.20.

[0033] The beneficial effects of this invention are: This invention produces a catalytic hydrogenation catalyst support with both high specific surface area and strong CO2 / CO adsorption capacity by co-generating a mixed dry powder of aluminum hydroxide / aluminum fumarate, followed by hydrothermal treatment and extrusion molding. The key lies in the hydrothermal treatment inducing the formation of a structure rich in highly active tricoordinated aluminum, significantly enhancing the L-acid sites and thus substantially improving the impurity resistance of the hydrogenation catalyst. Detailed Implementation

[0034] Polyethylene glycol, PEG-3350, is sourced from Dow Chemical Company in the United States.

[0035] Example 1

[0036] A method for preparing a hydrogenation catalyst support includes the following steps: S1. Add 15g of zirconium oxychloride to 1L of water at 80℃, then add 600mL of aluminum sulfate aqueous solution, 150mL of sodium aluminate aqueous solution, and 50mL of 12wt% sodium fumarate aqueous solution for neutralization. The aluminum sulfate aqueous solution has an alumina concentration of 8g / 100mL; the sodium aluminate aqueous solution has an alumina concentration of 26g / 100mL. The pH of the neutralization reaction is 8.8. After neutralization for 1 hour, perform hydrothermal treatment at 80℃ for 12 hours, followed by aging for 0.5 hours. The aging product is washed three times with deionized water to remove SO42-. 2- No more than 2.5%, Na + Not more than 0.05%, Fe 3+ Filter at a concentration not exceeding 0.25%, and dry at 110℃ for 24 hours to obtain a dry adhesive powder of aluminum hydroxide and aluminum fumarate. S2. Mix 100g of dry adhesive powder of aluminum hydroxide and aluminum fumarate, 3g of nitric acid and 10g of extrusion aid evenly, extrude into strips, dry at 110℃ for 3h and calcine at 500℃ for 3h to obtain hydrogenation catalyst support. The method for preparing the extrusion aid includes the following steps: Phosphorylcholine methacrylate and 2,2'-bipyridine were mixed and then added dropwise with a 20wt% aqueous solution of amino-terminated polyether. The mixture was heated to 60℃ and polymerized for 12 hours. Then, 4-azidobenzoic acid and bicycloamidin were added, and the mixture was heated to 80℃ for an addition reaction. After the reaction was completed in 8 hours, the extrusion aid was obtained after post-treatment. The mass ratio of phosphorylcholine methacrylate, 2,2'-bipyridine, amino-terminated polyether, azide monomer, and bicycloamidin was 1:0.015:3.5:0.5:0.01.

[0037] Example 2

[0038] It is basically the same as Example 1, except that 4-azidobenzoic acid is replaced with ethyl 2-azidobenzoic acid.

[0039] Example 3

[0040] It is basically the same as Example 1, except that 4-azidobenzoic acid is replaced with 5-azido-1,3-phthalic acid.

[0041] Compare with Example 1

[0042] It is basically the same as Example 1, except that no extrusion aid is added.

[0043] Compare with Example 2

[0044] It is basically the same as Example 1, except that the extrusion aid is replaced with guar gum powder.

[0045] Compare with Example 3

[0046] It is basically the same as Example 1, except that the extrusion aid is replaced with polyethylene glycol.

[0047] Test Example 1

[0048] The catalyst supports prepared in the examples and control examples were subjected to performance tests. The specific surface area and pore volume were determined by cryogenic liquid nitrogen adsorption method, while the total acid content, Brønsted acid content, and Lewis acid content were determined by pyridine infrared adsorption spectroscopy. The specific results are shown in Table 1.

[0049] Table 1 .

[0050] γ-Al₂O₃ is one of the most commonly used support materials for hydrogenation catalysts. Its crystal structure and surface properties make it particularly suitable as a catalyst support. Its specific surface area determines the dispersion of active components and the adsorption capacity of reactants, while pore volume affects mass transfer efficiency and macromolecular adaptability. The amount of acid (and the type of acid) regulates the reaction activity, selectivity, and stability. For most hydrogenation reactions, the main role of alumina as a support is physical support and metal dispersion. Its acidity, especially Brønsted acid and strong acid centers, is generally considered a detrimental factor, introducing side reactions and accelerating deactivation. Therefore, low total acidity, extremely low (ideally zero) Brønsted acid content, appropriate / controllable medium-strength Lewis acid content, and extremely low B / L ratio are key to improving the selectivity and stability of hydrogenation catalysts.

[0051] As shown in Table 1, the catalyst support prepared in this invention possesses a large pore volume, specific surface area, and acidity. This is likely due to the fact that the preparation method of the catalyst support in this invention involves simultaneously obtaining a dry gel powder of aluminum hydroxide and aluminum fumarate during the gelation process, followed by a hydrothermal treatment process, and then extruding the dry gel powder of aluminum hydroxide and aluminum fumarate to obtain the hydrogenation catalyst support. By utilizing the high specific surface area of ​​aluminum in aluminum fumarate and the metal-organic framework of fumarate, their strong adsorption capacity for CO2, and the formation of crystal nuclei by inorganic or organic additives, along with the addition of a hydrothermal treatment process during gelation, an alumina support with a lower Al coordination number can be formed, thereby improving the adsorption of CO by the support. The synergistic effect of the different characteristics of the two alumina dry gel powders improves the catalyst's resistance to impurities.

[0052] As shown in Table 1, the catalyst support prepared in the examples exhibits better performance compared to Control Examples 2-3. This may be due to the fact that the phosphorylcholine head group of the extrusion aid prepared in the examples provides lubrication, the polyether segments are responsible for pore formation, the tail end of the azide monomer chelates aluminum to enhance strength, and the residual phosphorus after calcination of the extrusion aid forms AlPO4 microdomains, increasing the proportion of tricoordinated aluminum. In the hydrogenation reaction, these strong L-acid sites can polarize C=O bonds, and the bimodal mesopores generated by the decomposition of polyether segments can improve mass transfer, all of which contribute to increasing pore volume and specific surface area. In addition, the extrusion aid synergistically achieves selective adsorption of poisons with aluminum fumarate MOF, protecting active sites and thus enhancing resistance to poisoning. In addition to its lubricating and mixing-promoting functions, the extrusion aid prepared in this invention can also indirectly regulate the pore structure of the support, thereby improving its performance. Therefore, its performance is significantly better than that of Control Example 1 without the added extrusion aid.

[0053] Compared with Examples 1 and 2, 5-azido-1,3-phthalic acid in Example 3 has a dicarboxyl group, which can form a double five-membered chelate ring with aluminum ions, resulting in higher chelate strength. The double chelate point induces the generation of three-coordinate aluminum ion defects, and the dicarboxyl group works together to create pores with a larger pore volume. Therefore, the overall performance is the best.

[0054] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a hydrogenation catalyst support, characterized in that, Includes the following steps: S1. Add the additives to water at 50~90℃, then carry out the neutralization reaction of aluminum sulfate aqueous solution, sodium aluminate aqueous solution and sodium fumarate aqueous solution. After the neutralization is completed, perform hydrothermal treatment, then carry out aging reaction. The aging product is washed, filtered and dried to obtain a dry adhesive powder of aluminum hydroxide and aluminum fumarate. S2. Mix the dry adhesive powder of aluminum hydroxide and aluminum fumarate, the adhesive solvent and the extrusion aid evenly, extrude into strips, and after drying and calcination, obtain the hydrogenation catalyst support.

2. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The method for preparing the extrusion aid includes the following steps: After mixing phosphorylcholine methacrylate and 2,2'-bipyridine, an aqueous solution of terminal amino polyether was added dropwise. The mixture was heated to 50-60°C and polymerized for 10-14 hours. Then, azide monomer and dicycloamidin were added, and the mixture was heated to 70-80°C for an addition reaction. The reaction was completed in 6-10 hours. After post-treatment, the extrusion aid was obtained.

3. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The additive is one or more inorganic salts selected from silicon, titanium, magnesium, boron, and zirconium, or may be derived from organic compounds; the organic compound is citric acid, citric anhydride, isocitric acid, malic acid, tartaric acid, oxalic acid, succinic acid, glutaric acid, adipic acid, benzoic acid, phthalic acid, isophthalic acid, salicylic acid, malonic acid, fatty alcohol, ethylene glycol, propylene glycol, glycerol, methyl methoxide, methyl methoxide propane, diethylene glycol, dipropylene glycol, methyl ethylene glycol, triethylene glycol, triethylene glycol, tributylene glycol, tetraethylene glycol, tetrapropylene glycol, polyethylene glycol, diethylene methyl glycol, diethylene ethyl glycol, diethylene propyl glycol, diethylene butyl glycol, or at least one selected from monosaccharides, disaccharides, and polysaccharides with 3 to 10 carbon atoms.

4. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The neutralization reaction conditions are a neutralization time of 0.4 to 1.5 hours and a pH value of 7.0 to 9.

5.

5. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The hydrothermal treatment reaction time is 4~24h, and the temperature is 70~90℃; the aging reaction time is 0.2~1h.

6. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The washing process typically involves 2-5 washes with deionized water until SO4 is removed. 2- No more than 2.5%, Na + Not more than 0.05%, Fe 3+ Not more than 0.25%; the drying conditions in step S1 are a drying temperature of 90~130℃ and a drying time of 5~34h.

7. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The ratio of aluminum hydroxide and aluminum fumarate in the dry adhesive powder is 9.0 to 0.4; the amount of extrusion aid is 0.1% to 20.0% of the dry basis weight of the mixed dry adhesive powder in step S1.

8. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The adhesive solvent can be one or more of aluminum sulfate, citric acid, nitric acid, acetic acid, oxalic acid, etc., and its amount accounts for 0.1% to 20.0% of the dry basis weight of the dry adhesive powder of aluminum hydroxide and aluminum fumarate mixed in step S1; the drying and calcination conditions in step S2 are as follows: drying at 100 to 120°C for 1 to 5 hours, and calcining at 400 to 550°C for 1 to 5 hours.

9. The method for preparing the hydrogenation catalyst support as described in claim 1, characterized in that, The hydrogenation catalyst support has a total acid content of 0.45~0.75 mmol / g, a Lewis acid content of 0.40~0.70 mmol / g, and a Brønsted acid / Lylene acid ratio of 0.07~0.25; the hydrogenation catalyst support has a pore volume of 0.4~1.2 mL / g and a specific surface area of ​​400~850 m². 2 / g.

10. A hydrogenation catalyst support, characterized in that, Prepared by the method described in any one of claims 1 to 9.