In-situ composite catalyst for catalytic hydrogenation of cornus wilsoniana oil as well as preparation method and application of in-situ composite catalyst
By using a 3D catalyst with bimetallic element in situ support and carbon coating, the problems of high cost and easy poisoning of biomass fuel catalysts in the existing technology have been solved, and a catalytic hydrogenation reaction with high selectivity and high conversion rate has been achieved, which meets the requirements for the preparation of aviation kerosene.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN ACAD OF FORESTRY
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-17
AI Technical Summary
Existing biomass fuel catalysts are expensive, prone to poisoning and deactivation, and cannot simultaneously meet the requirements of high selectivity and high conversion rate, thus limiting the industrial application of biomass fuels.
A 3D catalytic active site was constructed by in-situ loading of bimetallic elements and in-situ generation of carbon coating. The catalyst was prepared by a one-pot method, which improved the catalytic activity, dispersibility and stability. It was used for the catalytic hydrogenation of sclerophylla oil to prepare aviation kerosene.
It achieves high selectivity and high conversion rate, with a raw material conversion rate of 60% and a target product selectivity of 80%, meeting aviation kerosene standards and reducing production costs.
Smart Images
Figure CN121869431A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a biomass fuel catalyst, specifically to an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil, its preparation method, and its application, belonging to the field of catalytic hydrogenation technology. Background Technology
[0002] *Cornus sclerophylla* (commonly known as the smooth-barked tree) is an energy engineering tree species, and its fruit oil has attracted widespread attention from researchers as an ideal bioenergy feedstock. Although the liquid products of *Cornus sclerophylla* fruit oil can also become bioenergy fuels through cracking or hydrogenation, the presence of multiple straight-chain alkanes limits its low-temperature flow properties and thus its application scope. Currently, researchers are dedicated to using isomerization catalysts to isomerize waste oils and vegetable oils to increase the branched-chain alkanes content in the oils, thereby giving them good low-temperature flow properties.
[0003] Currently, the most intuitive research direction lies in the optimization of catalytic cracking or hydrogenation processes, which is more fundamentally reflected in the preparation and optimization of catalysts. Noble metal catalysts, due to their advantages of high reactivity, good selectivity, and high yield, have become the preferred research direction for various institutions. However, the high price and susceptibility to poisoning and deactivation of noble metal catalysts significantly increase the production cost of biomass fuels, thus limiting their promotion and application. To address this, some institutions have adopted a multi-metal catalyst blending approach, using base metals as auxiliary active elements to reduce the noble metal loading in the catalyst and improve catalytic performance. This method alleviates the high production cost problem to some extent, but it still cannot fundamentally solve the aforementioned issues.
[0004] Non-precious metal catalysts, especially base metal catalysts, have advantages such as low cost, wide availability, and stable properties. However, their reactivity is lower compared to precious metal catalysts, and for complex biomass feedstocks, they struggle to simultaneously meet the requirements of high selectivity and high conversion rates in catalytic hydrogenation, leading to decreased feedstock utilization and increased overall production costs. Furthermore, alkali metal catalysts are susceptible to poisoning, necessitating frequent cleaning of reaction byproducts, catalyst regeneration, or replacement during production. This exacerbates the complexity of catalytic hydrogenation processes and poses a potential risk of secondary environmental pollution.
[0005] Therefore, there is an urgent need for a catalytic hydrogenation catalyst with high catalytic activity, long catalytic lifetime, and low cost to meet the requirements of industrial production of biomass fuels. Summary of the Invention
[0006] To address the problems existing in the prior art, the first objective of this invention is to provide an in-situ composite catalyst for the catalytic hydrogenation of *Pterocarya stenoptera* oil. This composite catalyst is based on a "dual in-situ reaction" of in-situ loading of a bimetallic element and in-situ generation of a carbon-coated layer, constructing an integrated 3D catalytic active site within the catalyst. The in-situ loaded bimetallic element serves as the reaction center, while the embedded support and the surface-coated carbon layer constitute the surrounding environment. Through the synergistic effect between the two, the catalytic activity of the catalyst is significantly improved, while the dispersion, uniformity, and reaction stability of the reaction center are also effectively enhanced, thereby effectively ensuring the selectivity of the catalytic hydrogenation reaction.
[0007] The second objective of this invention is to provide a method for preparing an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil. This method employs a one-pot preparation process, forming a bimetallic element solution. Through over-volume impregnation, the desired element is embedded into a support, followed by reduction calcination and in-situ calcination to form an integrated 3D catalytic active site. This method is characterized by its simplicity, safety, stability, and low cost, and can meet the requirements for the industrial production of catalysts.
[0008] The third objective of this invention is to provide an application of an in-situ composite catalyst for the catalytic hydrogenation of *Scleroderma purpurea* oil, used in the preparation of aviation kerosene via catalytic hydrogenation of *Scleroderma purpurea* oil. Based on the structural characteristics of the catalyst, its application in the process of preparing aviation kerosene via catalytic hydrogenation of *Scleroderma purpurea* oil effectively solves the technical problem in existing technologies where it is difficult to simultaneously achieve high selectivity and high conversion rate. Tests have shown that when using the catalyst provided by this invention for the preparation of aviation kerosene, both the raw material conversion rate and product selectivity are above 80%, and its unsaturation, fluidity, and component content all meet the aviation kerosene standards, achieving the technical objective of regenerable aviation kerosene.
[0009] To achieve the above-mentioned technical objectives, the present invention provides an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil, comprising a support, a bimetallic element generated in situ on the support, and an in-situ carbon layer uniformly attached to the surface of the bimetallic element.
[0010] The bimetallic element is composed of alkali metal elements and non-precious metal elements, and its mass percentage is 0.5~10wt% of the total mass of the composite catalyst; the thickness of the in-situ carbon layer is 0.5~2nm.
[0011] In the technical solution provided by this invention, the loading of bimetallic elements and the thickness of the in-situ carbon layer must strictly comply with the above requirements. If the loading of bimetallic elements is too high, it will increase the probability of metal element aggregation, thereby reducing catalytic activity. If the loading of bimetallic elements is too low, the number of active centers will be too small, which will also lead to a decrease in catalytic activity. In addition, the in-situ carbon layer can, on the one hand, work with the support to spatially confine the bimetallic elements and prevent metal element aggregation, and on the other hand, it can isolate the raw materials from direct contact with the metal elements, effectively extending the catalyst life. However, it should be noted that the thickness of the carbon layer should not be too thick. If the carbon layer is too thick, it will be difficult for the metal elements to directly produce a catalytic effect on the raw materials.
[0012] As a preferred embodiment, the carrier is one of molecular sieve and / or porous ceramic.
[0013] As a preferred embodiment, when the carrier is a molecular sieve, it is one of ZSM-5, HZSM-5, SAPO-11, and SAPO-34.
[0014] As a preferred embodiment, the alkali metal element is one of Li, Na, and K.
[0015] As a preferred embodiment, the non-precious metal element is one of Cu, Fe, Mn, Ni, and Zn.
[0016] As a preferred embodiment, the molar ratio of the alkali metal element to the non-precious metal element is 0.5 to 2.
[0017] This invention also provides a method for preparing an in-situ composite catalyst for the catalytic hydrogenation of *Pterocarya stenoptera* oil. The process is as follows: a bimetallic element raw material is dissolved in deionized water under stirring, a dispersant is slowly added and uniformly dispersed, a carrier is added while stirring, and after sufficient impregnation, the catalyst is dried and calcined in two stages to obtain the final product.
[0018] As a preferred embodiment, the bimetallic raw material is composed of alkali metal element raw material and non-precious metal element raw material.
[0019] As a preferred embodiment, the alkali metal element raw material includes alkali metal element hydroxides and soluble salts.
[0020] As a preferred embodiment, the non-precious metal element raw materials include hydroxides and soluble salts of alkali metal elements.
[0021] As a preferred embodiment, when the alkali metal element is sodium, the alkali metal element raw material is at least one selected from sodium hydroxide, sodium carbonate, sodium bis(oxalato)borate, sodium iron phosphate, and sodium bis(fluorosulfonyl)imide.
[0022] As a preferred embodiment, when the non-precious metal element is copper, the non-precious metal element raw material is at least one of copper nitrate, copper sulfate, and copper chloride.
[0023] As a preferred embodiment, the dispersant is one of polyvinyl alcohol 400, polyvinyl alcohol 600 and polyvinyl alcohol 800, and its addition amount is 0.05~1.5wt% of the total mass of the catalyst.
[0024] In this invention, the dispersant can serve as a template agent to fully mix alkali metal raw materials and non-precious metal elements. On the other hand, it can also serve as a carbon source in the subsequent calcination process to form a uniform carbon layer on the catalyst surface. Therefore, the addition of the dispersant must be strictly carried out in accordance with the above requirements. Too much dispersant will result in an excessively thick carbon layer, while too little dispersant will prevent the uniform dispersion of the raw materials.
[0025] As a preferred embodiment, the stirring speed is 100~300 r / min.
[0026] As a preferred embodiment, the drying conditions are: drying at 15~40°C to constant weight under an inert atmosphere.
[0027] As a preferred embodiment, the two-stage calcination process consists of reduction calcination and in-situ calcination. The process is as follows: under a hydrogen atmosphere, the temperature is raised from room temperature to 180-240°C at 3-5°C and maintained for 1-3 hours. Then, an inert atmosphere is introduced to completely replace the hydrogen, and the temperature is raised to 300-400°C at 8-12°C and maintained for 0.5-1.5 hours. The furnace is then cooled to room temperature to obtain the final product.
[0028] One of the key technical features of the preparation method provided by this invention is the two-stage calcination. The reduction calcination mainly reduces non-precious metal elements, thereby optimizing the catalytic pathway and improving catalytic activity. The in-situ calcination, on the other hand, uses a higher temperature to induce mesoporous formation in the support, while simultaneously allowing the metal elements to be firmly embedded in the support and forming a uniform carbon layer on the surface of the metal elements in situ, thus improving the catalyst's anti-coking performance. It should be noted that the reduction stage cannot be carried out before calcination. If the reduction is carried out in advance, it may cause the non-precious metal elements to precipitate or complex, thus preventing the non-precious metal elements from being embedded in the support.
[0029] This invention also provides an application of an in-situ composite catalyst for the catalytic hydrogenation of *Scleroderma purpurea* oil, used for the catalytic hydrogenation of *Scleroderma purpurea* oil to produce aviation kerosene.
[0030] As a preferred embodiment, the conditions for the catalytic hydrogenation of *Pterocarya stenoptera* oil to prepare aviation kerosene are as follows: catalyst addition of 3-10 wt%, reaction temperature of 200-300℃, reaction time of 1-2 h, hydrogen pressure of 2-3 MPa, and stirring speed of 500-700 rpm.
[0031] Compared with the prior art, the beneficial technical effects of the technical solution provided by the present invention are as follows:
[0032] 1) The composite catalyst provided by this invention is based on the "dual in-situ reaction" of in-situ loading of bimetallic elements and in-situ generation of carbon coating, which constructs an integrated 3D catalytic active site in the catalyst. The in-situ loaded bimetallic elements are the reaction centers, while the embedded support and the surface carbon coating constitute the surrounding environment. Through the synergistic effect between the two, the catalytic activity of the catalyst is greatly improved, and the dispersion and uniformity of the reaction centers are also effectively improved, thereby effectively ensuring the selectivity of the catalytic hydrogenation reaction.
[0033] 2) The preparation method provided by the present invention adopts a one-pot preparation method, forming a bimetallic element solution, and using over-volume impregnation to embed the desired element into the support, and then forming an integrated 3D catalytic active site through reduction calcination and in-situ calcination; the method has the characteristics of simple process, safety and stability and low cost, and can meet the requirements of industrial production of catalysts.
[0034] 3) In the technical solution provided by the present invention, based on the structural characteristics of the above-mentioned catalyst, its application in the process of catalytic hydrogenation of sclerophylla oil to prepare aviation kerosene can effectively solve the technical problem in the existing technology that it is difficult to achieve both high selectivity and high conversion rate in the production process. According to the test, when the catalyst provided by the present invention is used to prepare aviation kerosene, the raw material conversion rate can reach 60%, the target product selectivity can reach more than 80%, and its unsaturation, fluidity and component content and other indicators also meet the aviation kerosene execution standards, thus realizing the technical goal of aviation kerosene renewability. Attached Figure Description
[0035] Figure 1 This is an electron microscope image of the catalyst provided in Example 1 of the present invention;
[0036] in, Figure 1 (a) is the HRTEM image of the catalyst. Figure 1 (b) is the lattice pattern of the carbon layer of the catalyst;
[0037] Figure 2 XPS plot of the catalyst provided in Example 1 of this invention;
[0038] Figure 3 The image shows the XRD pattern of the catalyst obtained in Example 4 of this invention. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of the present invention.
[0040] Example 1
[0041] This embodiment provides an in-situ composite catalyst for the catalytic hydrogenation of *Pterocarya stenoptera* oil. The specific preparation process is as follows: 0.01 mol sodium nitrate and 0.02 mol copper nitrate are dissolved in 0.2 L of deionized water. 0.8 g of polyvinyl alcohol 400 is slowly added while stirring at 150 r / min. After sufficient dispersion, 10 g of Na-type ZSM-5 molecular sieve is added, and the mixture is impregnated for 24 h while maintaining stirring to obtain the catalyst precursor. The catalyst precursor is then removed and dried at room temperature under N2 atmosphere to constant weight. Subsequently, it is placed in a tube furnace for sequential reduction calcination and in-situ calcination to obtain the final product.
[0042] The reduction calcination process is as follows: under a hydrogen atmosphere, the temperature is increased from room temperature to 220°C at 3°C and held for 1.5 hours; the in-situ calcination process is as follows: N2 is introduced to completely replace the hydrogen, and then the temperature is increased to 350°C at 12°C and held for 1 hour.
[0043] In this embodiment, the molar ratio of Na to Cu in the catalyst is 1:1.8, and the sum of their masses accounts for 5.3% of the catalyst. The average thickness of the in-situ carbon layer obtained on the catalyst surface is 0.85 nm.
[0044] Example 2
[0045] This embodiment is exactly the same as Example 1, except that: sodium nitrate is 0.005 mol and copper nitrate is 0.01 mol. In the catalyst obtained in this embodiment, the molar ratio of Na to Cu is 1:1.8, and the sum of their masses accounts for 1.8% of the catalyst.
[0046] Example 3
[0047] This embodiment is exactly the same as Example 1, except that the in-situ calcination temperature is 300°C. Due to the decrease in calcination temperature, the average thickness of the in-situ carbon layer obtained on the surface of the catalyst is only 0.56 nm.
[0048] Comparative Example 1
[0049] This comparative example is exactly the same as that of Example 1, except that: sodium nitrate is 0.02 mol and copper nitrate is 0.04 mol. In the catalyst obtained in this example, the molar ratio of Na to Cu is 1:1.8, and the sum of their masses accounts for 12.3% of the catalyst.
[0050] Comparative Example 2
[0051] This comparative example is exactly the same as that of Example 1, except that the in-situ calcination temperature is 500°C. Due to the increased calcination temperature, the average thickness of the in-situ carbon layer obtained on the surface of this catalyst is only 2.8 nm.
[0052] This invention presents experiments on the catalytic hydrogenation of *Gnaphalium affine* oil to prepare aviation kerosene in the above-described embodiments and comparative examples. The process is as follows: 100g of *Gnaphalium affine* oil is added to a solvothermal reactor, followed by 5g of catalyst, and the mixture is thoroughly mixed. The reactor is then closed, and the air inside is completely replaced with nitrogen. The exhaust valve is then closed, and hydrogen is introduced while the reactor is heated to the reaction temperature under stirring to carry out the catalytic hydrogenation reaction. After the reaction, the mixture is cooled to room temperature with the furnace, filtered, and dehydrated to obtain the final product. The conditions for the above catalytic hydrogenation reaction are: reaction temperature 250℃, hydrogen pressure 2MPa, and stirring speed 500rpm. The experimental results are shown in Table 1.
[0053]
[0054] As shown in Table 1, the catalysts obtained in Examples 1-3 all achieved conversion rates above 60% and selectivity above 80% in the preparation of aviation kerosene, effectively solving the problem of simultaneously achieving high selectivity and high conversion rates in existing technologies. Although the catalyst obtained in Comparative Example 1 increased the metal loading, its excessive loading negatively impacted the dispersion of metal elements, thus affecting the catalytic activity and resulting in a conversion rate of only 56%. In Comparative Example 2, while increasing the sintering temperature helped with the intercalation and dispersion of metal elements, the excessively high temperature caused some carbon to intercalate into the micropores and mesopores of the support, leading to an excessively thin surface carbon layer that failed to provide confinement, resulting in a significant decrease in catalytic performance.
[0055] Furthermore, the products obtained by catalysis in Examples 1-3 were subjected to quality inspection in accordance with the standard of "No. 3 Jet Fuel" (GB 6537-2025). The products were found to meet the above standard and can be used as aviation kerosene.
Claims
1. An in-situ composite catalyst for catalytic hydrogenation of alder oil, characterized in that: It includes a carrier, a bimetallic element generated in situ on the carrier, and an in situ carbon layer uniformly attached to the surface of the bimetallic element; The bimetallic element is composed of alkali metal elements and non-precious metal elements, and its mass percentage is 0.5~10wt% of the total mass of the composite catalyst; the thickness of the in-situ carbon layer is 0.5~2nm.
2. The in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to claim 1, characterized in that: The support is one of molecular sieve and / or porous ceramic; when the support is a molecular sieve, it is one of ZSM-5, HZSM-5, SAPO-11 and SAPO-34.
3. The in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to claim 1, characterized in that: The alkali metal element is one of Li, Na, and K; the non-precious metal element is one of Cu, Fe, Mn, Ni, and Zn; and the molar ratio of the alkali metal element to the non-precious metal element is 0.5 to 2.
4. A method for preparing an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to any one of claims 1 to 3, characterized in that: The bimetallic element raw material is dissolved in deionized water under stirring. A dispersant is slowly added and evenly dispersed. The carrier is added while stirring. After sufficient impregnation, the mixture is dried and calcined in two stages to obtain the final product.
5. The method for preparing an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to claim 4, characterized in that: The bimetallic raw material is composed of alkali metal element raw material and non-precious metal element raw material; the alkali metal element raw material includes alkali metal element hydroxide and soluble salt; the non-precious metal element raw material includes alkali metal element hydroxide and soluble salt.
6. The method for preparing an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to claim 5, characterized in that: When the alkali metal element is sodium, the alkali metal element raw material is at least one of sodium hydroxide, sodium carbonate, sodium bis(fluorosulfonyl)imide, sodium oxalate, sodium iron phosphate, and sodium bis(fluorosulfonyl)imide; when the non-precious metal element is copper, the non-precious metal element raw material is at least one of copper nitrate, copper sulfate, and copper chloride.
7. The method for preparing an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to claim 4, characterized in that: The dispersant is one of polyvinyl alcohol 400, polyvinyl alcohol 600 and polyvinyl alcohol 800, and its addition amount is 0.05~1.5wt% of the total mass of the catalyst.
8. The method for preparing an in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to claim 4, characterized in that: The stirring speed is 100~300 r / min; the drying conditions are: drying to constant weight at 15~40℃ under an inert atmosphere; the two-stage calcination process consists of reduction calcination and in-situ calcination, the process is as follows: under a hydrogen atmosphere, the temperature is raised from room temperature to 180~240℃ at 3~5℃ and maintained for 1~3h, then an inert atmosphere is introduced to completely replace the hydrogen, and then the temperature is raised to 300~400℃ at 8~12℃ and maintained for 0.5~1.5h, and then cooled to room temperature with the furnace to obtain the final product.
9. The application of the in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to any one of claims 1 to 3, characterized in that: Used for the catalytic hydrogenation of bark oil to produce aviation kerosene.
10. The application of the in-situ composite catalyst for the catalytic hydrogenation of *Gnaphalium affine* oil according to claim 9, characterized in that: The conditions for the catalytic hydrogenation of *Gnaphalium affine* oil to prepare aviation kerosene are as follows: catalyst addition of 3-10 wt%, reaction temperature of 200-300℃, reaction time of 1-2 h, hydrogen pressure of 2-3 MPa, and stirring speed of 500-700 rpm.