In-situ catalytic deoxygenation and hydrogenation process and catalyst

Abstract

The present application relates to the field of biomass high-value utilization and fine chemical catalysis, in particular to a method and catalyst for in-situ catalytic deoxygenation and hydrogenation, comprising the steps of synthesis of a bifunctional catalyst, preparation of a phase change microcapsule hydrogen storage material and programmed temperature hydrogenation deoxygenation; the method combines phase change microcapsule technology and programmed temperature strategy to construct a ternary ladder hydrogen supply system with liquid, solid and gas sources; the core is to integrate dehydrogenation and bond-breaking deoxygenation centers using a catalyst, to accurately segment hydrogen production at different temperature zones, and to highly match the hydrogen supply rate with the actual hydrogen consumption demand of each stage of the substrate; the present application overcomes the dependence of traditional hydrogenation technology on external high-pressure hydrogen, solves the problems of high-pressure storage and transportation risk and low single hydrogen supply deoxygenation rate by using in-situ self-generated pressure, effectively overcomes the contradiction of ineffective hydrolysis of solid hydrogen storage, and greatly improves the deep deoxygenation efficiency and catalyst cycle stability.

Description

Technical Field

[0001] This invention relates to the fields of biomass high-value utilization and fine chemical catalysis technology, specifically to an in-situ catalytic deoxygenation hydrogenation method and catalyst. Background Technology

[0002] Hydrodeoxygenation of oxygenated biomass derivatives is a key step in the preparation of high-quality liquid fuels and high-value-added chemicals. Most existing hydrodeoxygenation technologies rely on external high-pressure hydrogen supply, which not only imposes strict requirements on the pressure resistance of the reaction equipment, but also places extremely stringent requirements on the system operating pressure and engineering control conditions during storage, transportation and use. To reduce reliance on high-pressure hydrogen, existing technologies have proposed in-situ hydrogen supply solutions. However, current in-situ hydrogen supply technologies still face the following technical bottlenecks: when using a single liquid hydrogen donor, the in-situ hydrogen supply is limited due to thermodynamic equilibrium, resulting in low deoxygenation rates and reaction conversion rates of the target product; while using elemental metals for hydrogen supply under high-temperature hydrothermal conditions improves the hydrogen supply capacity, it consumes a large amount of metal, generates a large amount of difficult-to-treat metal oxide waste, and the reaction conditions are relatively harsh; traditional hydrodeoxygenation processes usually require the hydrogen supply reaction and the hydrodeoxygenation reaction to be carried out stepwise in different reactors or under completely different reaction conditions, resulting in long process flows and low space-time yields. Summary of the Invention

[0003] The purpose of this invention is to provide an in-situ catalytic deoxygenation and hydrogenation method and catalyst, aiming to solve the technical defects of existing technologies, such as high safety risks due to reliance on external high-pressure hydrogen for hydrogenation and deoxygenation, low deoxygenation rate and high metal consumption due to single in-situ hydrogen supply, and long process flow and low space-time yield due to the stepwise operation of hydrogen supply and deoxygenation reaction. Specifically, the technical solution of this invention is as follows: A catalyst includes a support and a platinum-containing component and a molybdenum-containing component supported on the support; wherein the support comprises titanium dioxide; the mass fraction of the platinum-containing component in the catalyst is 0.5 wt%-2.0 wt%, and the mass fraction of the molybdenum-containing component is 5.0 wt%-10.0 wt%, the mass fractions of the aforementioned platinum-containing component and molybdenum-containing component are calculated as elemental platinum and molybdenum oxide, respectively; the catalyst is prepared by a method comprising the following steps: mixing a platinum source solution and a molybdenum source solution, adding an acidic adjuster to adjust the pH value to 2.0-3.0 to prepare a mixed impregnation solution; loading the mixed impregnation solution onto the support using an equal-volume co-impregnation method, and drying and calcining to prepare an oxidized precursor; and subjecting the oxidized precursor to a reducing atmosphere by heating and reduction to prepare the catalyst.

[0004] Preferably, the platinum source solution includes a chloroplatinic acid solution, the molybdenum source solution includes an ammonium metamolybdate solution, the support includes anatase titanium dioxide, and the acid regulator includes dilute nitric acid.

[0005] Preferably, the drying process parameters include: drying under vacuum at a temperature of 70℃-90℃ for 10h-14h; and the calcination process parameters include: calcining in air at a temperature of 400℃-500℃ for 3h-5h; and the temperature-increasing reduction process parameters include: heating to 350℃-400℃ in a hydrogen-containing reducing atmosphere using a programmed temperature increase method, and performing a reduction reaction for 2h-4h.

[0006] Preferably, the process includes the following steps: mixing the reaction substrate, reaction solvent, liquid hydrogen donor, solid chemical hydrogen storage material and catalyst in a reactor equipped with a back pressure regulating valve, performing gas replacement treatment, and then introducing a mixed gas containing carbon monoxide; subjecting the reactor to programmed temperature increase to carry out a hydrodeoxygenation reaction to prepare a hydrodeoxygenation product.

[0007] Preferably, the reaction substrate is one or more of a biomass oxygen-containing model and bio-oil; wherein the biomass oxygen-containing model includes guaiacol; the bio-oil includes soybean oil; and the reaction solvent includes a mixed solvent of water and dodecane; and the liquid hydrogen donor includes a buffer solution composed of formic acid and alkali metal formate; and the carbon monoxide-containing mixed gas is biomass pyrolysis gas or simulated biomass pyrolysis gas.

[0008] Preferably, the in-situ catalytic deoxygenation hydrogenation method has one or more of the following characteristics: (1) In the mixed solvent of water and dodecane, the volume ratio of water to dodecane is 1:(0.8-1.2); (2) In the buffer solution composed of formic acid and alkali metal formate, the molar ratio of formic acid to formate is 1:(0.8-1.2). (3) In the mixed gas containing carbon monoxide, the volume fraction of carbon monoxide is 25%-35%, the volume fraction of carbon dioxide is 15%-25%, the volume fraction of nitrogen is 45%-55%, and the sum of the volume fractions of each component is 100%; (4) The amount of catalyst added is 3wt%-8wt% of the mass of the reaction substrate.

[0009] Preferably, the solid-state chemical hydrogen storage material comprises microcapsules, each microcapsule comprising a wall material and a core material encapsulated by the wall material; wherein the wall material comprises one or more of a phase change wax and a polymer; the polymer is an ethylene-vinyl acetate copolymer; and the core material comprises sodium borohydride or nano-magnesium nickel hydride.

[0010] Preferably, the preparation method of the microcapsules includes the following steps: heating the wall material to 145℃-160℃ to completely melt it, adding the core material, and mixing it at a stirring speed of 500rpm-1000rpm for 10min-30min, then adding a silicone oil dispersion medium containing emulsifier for emulsification treatment, and then cooling and solidifying it to room temperature at a cooling rate of 2℃ / min-5℃ / min, and finally filtering it and drying it under vacuum at 40℃-60℃ for 12h-24h.

[0011] Preferably, the programmed temperature rise step includes a first-stage reaction, a second-stage reaction, and a third-stage reaction in sequence; the process parameters for the first-stage reaction include: a temperature of 80℃-120℃ and a time of 0.5h-2h; the process parameters for the second-stage reaction include: a temperature of 120℃-180℃ and a time of 1h-2h; and the process parameters for the third-stage reaction include: a temperature of 180℃-280℃ and a time of 1.5h-3h.

[0012] Preferably, the in-situ catalytic deoxygenation hydrogenation method has one or more of the following characteristics: (1) The heating rate of the first stage reaction is 2℃ / min-5℃ / min; (2) The charging pressure of the mixed gas containing carbon monoxide is 0.5 MPa-1.0 MPa; (3) During the hydrodeoxygenation reaction, the pressure inside the reactor is controlled by the back pressure regulating valve, and the set threshold of the back pressure regulating valve is 3.0MPa-5.0MPa; (4) After the hydrodeoxygenation reaction is completed, the process further includes: cooling the reactor with a cold trap, collecting the gas phase components through a membrane separation device, and allowing the reaction liquid to stand and separate into layers to obtain an organic phase and an aqueous phase, wherein the organic phase is the hydrodeoxygenation product, and centrifuging the aqueous phase and the interface between the two phases to recover the catalyst.

[0013] The beneficial effects of this invention are as follows: The ternary hydrogen supply system constructed in this invention requires only a low initial auxiliary pressure, and can complete deep hydrogenation and deoxygenation by adjusting the internal self-generated pressure and back pressure valve; it reduces the pressure resistance requirements of the high-pressure reactor, overcomes the dependence of traditional high-pressure hydrogen storage and transportation on harsh reaction conditions, and improves the intrinsic safety of the process. By using phase change microencapsulation technology and programmed temperature rise strategy, the contradiction that solid hydrogen storage materials are prone to low-temperature ineffective hydrolysis in aqueous phase is solved; segmented hydrogen production of liquid hydrogen donor, solid chemical hydrogen storage material and mixed gas containing carbon monoxide is realized in different temperature ranges, so that the hydrogen supply rate matches the actual hydrogen consumption demand of the substrate at each stage. The catalyst provided by this invention integrates dehydrogenation centers and bond-breaking deoxygenation centers. During the reaction, hydrogen species generated from multiple sources can continuously overflow at the interface between the platinum-containing and molybdenum-containing components, promptly removing and clearing oxygen-containing intermediates and coke precursors strongly adsorbed on oxygen vacancies, thus kinetically preventing deep oxidation and carbon deposition deactivation of oxygen-loving sites. Detailed Implementation

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below; the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0015] Example 1: This embodiment provides an in-situ catalytic deoxygenation hydrogenation method, employing a preferred parameter combination, as follows: S1.Pt-MoO x Preparation of the TiO2 bifunctional catalyst: 10.0 g of anatase TiO2 support was taken, and the loading was calculated based on a Pt mass fraction of 1.0 wt% and a MoO3 mass fraction of 8.0 wt%. A chloroplatinic acid solution and an ammonium molybdate solution were mixed, and the pH of the mixture was adjusted to 2.5 by adding 2.5 mL of 0.5 mol / L dilute nitric acid. Deionized water was added to bring the total volume of the mixed impregnation solution to 8.0 mL, yielding a mixed impregnation solution. The mixed impregnation solution was added to the TiO2 support using a co-impregnation method and allowed to stand for impregnation. The impregnated sample was vacuum dried at 80 °C for 12 h and calcined at 450 °C in air for 4 h to obtain an oxidized precursor. The oxidized precursor served as the metal source and structural basis for the subsequent reduction preparation of the bifunctional catalyst. The oxidized precursor was placed in a tube furnace, and a 10% H2 / Ar mixed gas was introduced. The temperature was raised to 375 °C using a programmed temperature rise method and held for 3 h to obtain Pt-MoO2. x / TiO2 catalyst; S2. Preparation of sodium borohydride microcapsules: 6.0 g of polyethylene phase change wax with a melting point of 130℃ was heated to 150℃ to melt it, and 4.0 g of sodium borohydride was added. The mixture was melted and mixed at 800 rpm for 20 min. The mixture was then added to 40 mL of dimethyl silicone oil dispersion medium with a viscosity of 100 cSt containing 0.5 g of emulsifier sorbitan monostearate. The mixture was emulsified for 15 min and cooled to room temperature at a cooling rate of 3℃ / min to solidify the molten wall material. After filtration, the mixture was vacuum dried at 50℃ for 18 h to obtain sodium borohydride microcapsules. The sodium borohydride microcapsules served as a temperature-controlled slow-release solid hydrogen source in the system to avoid ineffective hydrogen release at low temperatures. The mass fraction of sodium borohydride core material in the microcapsules was determined to be 40%. S3. Reactant Loading: Add 5.0 g of guaiacol, 20 mL of ultrapure water, 20 mL of dodecane, 2.10 g of formic acid, 3.11 g of sodium formate, 1.20 g of the above-mentioned sodium borohydride microcapsules, and Pt-MoO to a 100 mL high-pressure reactor equipped with magnetic stirring, programmed temperature control, and a back pressure regulating valve. x / TiO2 catalyst 0.25g; catalyst addition amount is 5wt% of substrate mass; after sealing, it is replaced with high-purity nitrogen 4 times, and then simulated biomass pyrolysis gas is introduced to the initial pressure of 0.8MPa. The volume fraction of CO in the pyrolysis gas is 30%, the volume fraction of CO2 is 20%, and the volume fraction of N2 is 50%; the back pressure regulating valve is set to a threshold of 4.0MPa; S4. Programmed temperature reaction: The reactor was heated to 100℃ at a rate of 3℃ / min and held for 1 hour; then heated to 150℃ and held for 1.5 hours; then heated to 240℃ and held for 2 hours; the reaction was continuously stirred at a stirring rate of 500 rpm during the reaction, and the reaction pressure changes were recorded online. S5. Product Separation and Catalyst Recovery: After the reaction is completed, the mixture is cooled to room temperature in a cold trap. The mixed gas in the system is then passed into a gas separation membrane device for gas-liquid separation and purification, and the gas phase components are collected. The reaction liquid is allowed to stand and separate into layers, separating the organic phase and the aqueous phase. The aqueous phase and the interface between the two phases are centrifuged to recover the catalyst and use it for recycling experiments. The organic phase is used for composition analysis and deoxygenation evaluation.

[0016] Example 2: This embodiment provides an in-situ hydrogen supply-hydrogenation deoxygenation coupling process, with parameters taken as the lower limit of the range defined in this invention, as follows; S1. Catalyst preparation: The catalyst preparation method is the same as in Example 1, except that: the pH of the mixed impregnation solution is adjusted to 2.0; the sample after impregnation is vacuum dried at 70°C for 10 h and calcined at 400°C in air atmosphere for 3 h; the precursor is reduced at 350°C for 2 h in 10% H2 / Ar atmosphere. S2. Preparation of sodium borohydride microcapsules: Take 6.0 g of polyethylene phase change wax with a melting point of 125℃, heat it to 145℃ to melt it, add 4.0 g of sodium borohydride, mix at 600 rpm for 15 min, emulsify it, cool it to room temperature at 2℃ / min, and vacuum dry it at 40℃ for 12 h. S3. Reactant loading: Add 5.0g of guaiacol, 20mL of ultrapure water, 16mL of dodecane, 2.10g of formic acid, 2.49g of sodium formate, 1.20g of sodium borohydride microcapsules, and 0.15g of catalyst to a 100mL high-pressure reactor; the volume ratio of water to dodecane is 1:0.8, the molar ratio of formic acid to sodium formate is 1:0.8, and the catalyst addition is 3wt%; after purging with high-purity nitrogen four times, a mixed gas with CO volume fraction of 25%, CO2 volume fraction of 20%, and N2 volume fraction of 55% is introduced to 0.5MPa; the back pressure regulating valve is set to a threshold of 3.0MPa; S4. Programmed temperature reaction: The reactor was heated to 80℃ at a rate of 2℃ / min and held for 0.5h; then heated to 120℃ and held for 1h; then heated to 220℃ and held for 1.5h; the reaction was continuously stirred at a stirring rate of 400rpm during the reaction, and the reaction pressure changes were recorded online. S5. Product processing: The product separation and catalyst recovery methods are the same as in Example 1.

[0017] Example 3: This embodiment provides an in-situ hydrogen supply-hydrogenation deoxygenation coupling process, with parameters taken as the upper limit within the range defined by this invention, as follows; S1. Catalyst preparation: The catalyst preparation method is the same as in Example 1, except that: the pH of the mixed impregnation solution is adjusted to 3.0; the sample after impregnation is vacuum dried at 90°C for 14 hours and calcined at 500°C in air atmosphere for 5 hours; the precursor is reduced at 400°C for 4 hours under 10% H2 / Ar. S2. Preparation of sodium borohydride microcapsules: Take 6.0 g of polyethylene phase change wax with a melting point of 140℃, heat it to 160℃ to melt it, add 4.0 g of sodium borohydride, mix at 1000 rpm for 30 min, emulsify it, cool it to room temperature at 5℃ / min, and vacuum dry it at 60℃ for 24 h. S3. Reactant loading: Add 5.0 g of guaiacol, 20 mL of ultrapure water, 24 mL of dodecane, 2.10 g of formic acid, 3.73 g of sodium formate, 1.20 g of sodium borohydride microcapsules, and 0.40 g of catalyst to a 100 mL high-pressure reactor; the volume ratio of water to dodecane is 1:1.2, the molar ratio of formic acid to sodium formate is 1:1.2, and the catalyst addition is 8 wt%; after purging with high-purity nitrogen four times, a mixed gas with CO volume fraction of 35%, CO2 volume fraction of 20%, and N2 volume fraction of 45% is introduced to 1.0 MPa; the back pressure regulating valve is set to a threshold of 5.0 MPa; S4. Programmed temperature reaction: The reactor was heated to 120℃ at a rate of 5℃ / min and held for 2 hours; then heated to 180℃ and held for 2 hours; then heated to 280℃ and held for 3 hours; the reaction was continuously stirred at a stirring rate of 800 rpm during the reaction, and the reaction pressure changes were recorded online. S5. Product processing: The product separation and catalyst recovery methods are the same as in Example 1.

[0018] Example 4: This embodiment provides another in-situ hydrogen supply-hydrogenation deoxygenation coupling process, in which the solid hydrogen storage material is selected as nano-hydride magnesium-nickel alloy microcapsules, as detailed below; S1. Catalyst preparation: The catalyst preparation method is the same as in Example 1; S2. Preparation of nano-hydrogenated magnesium-nickel alloy: 5.5g of polyethylene phase change wax with a melting point of 132℃ and 0.5g of ethylene-vinyl acetate copolymer were heated to 152℃ to form a homogeneous melt. 4.0g of nano-hydrogenated magnesium-nickel alloy with a particle size of 50-100nm was added and mixed at 850rpm for 20min. After adding 40mL of dimethyl silicone oil dispersion medium containing 0.5g of emulsifier sorbitan monostearate, emulsification was performed, followed by cooling to room temperature at 3℃ / min. The mixture was filtered and vacuum dried at 50℃ for 18h to obtain nano-hydrogenated magnesium-nickel alloy microcapsules. S3. Reactant loading: Add 5.0g soybean oil, 20mL ultrapure water, 20mL dodecane, 2.10g formic acid, 3.11g sodium formate, 1.20g nano-hydride magnesium nickel microcapsules, and 0.25g catalyst to a 100mL high-pressure reactor; after purging with high-purity nitrogen four times, introduce a mixed gas with 30% CO, 20% CO2, and 50% N2 volume fraction to 0.9MPa; set the back pressure regulating valve threshold to 4.0MPa. S4. Temperature-programmed reaction: The reactor is heated to 110℃ at a rate of 3℃ / min and held for 1 hour; then heated to 160℃ and held for 1.5 hours; then heated to 230℃ and held for 2 hours. S5. Product processing: The product separation and catalyst recovery methods are the same as in Example 1.

[0019] Comparative Example 1: The difference between this comparative example and Example 1 is that the liquid hydrogen donors formic acid and sodium formate are omitted, while the other operating steps and process parameters are exactly the same as in Example 1.

[0020] Comparative Example 2: The difference between this comparative example and Example 1 is that the sodium borohydride microcapsules, a solid chemical hydrogen storage material, are omitted. All other operating steps and process parameters are exactly the same as in Example 1.

[0021] Comparative Example 3: The difference between this comparative example and Example 1 is that the sodium borohydride microcapsules are replaced with the same mass of uncoated sodium borohydride powder, while the other operating steps and process parameters are exactly the same as in Example 1.

[0022] Comparative Example 4: The difference between this comparative example and Example 1 is that the initial charging gas is replaced with a CO-containing mixed gas, while the initial pressure remains at 0.8 MPa. The other operating steps and process parameters are exactly the same as in Example 1.

[0023] Comparative Example 5: The difference between this comparative example and Example 1 is that the catalyst is replaced with a Pt / TiO2 catalyst. The preparation process of this catalyst is the same as that of Example 1, but ammonium molybdate solution is not added. Other operating steps and process parameters are exactly the same as those of Example 1.

[0024] Comparative Example 6: The difference between this comparative example and Example 1 is that the catalyst is replaced with MoO2. x The / TiO2 catalyst was prepared in the same way as in Example 1, but without the addition of chloroplatinic acid solution. Other operating steps and process parameters were exactly the same as in Example 1.

[0025] Comparative Example 7: The difference between this comparative example and Example 1 is that the three-stage temperature program is cancelled, and the temperature is directly increased to 240°C at 3°C / min and held for 4.5 hours. Other operating steps and process parameters are exactly the same as in Example 1.

[0026] Substrate conversion and liquid phase product selectivity were determined using gas chromatography with external and internal standard methods. The main hydrocarbon products for guaiacol were cyclohexane and methylcyclohexane, while the main hydrocarbon products for soybean oil were C15-C18 long-chain alkanes. The deoxygenation rate was calculated by analyzing the product composition using organic phase elemental analysis combined with gas chromatography-mass spectrometry. The peak pressure during the reaction process was recorded using an online pressure sensor, and the catalyst cycle retention rate was evaluated by the ratio of the conversion rate in the 5th cycle to that in the 1st cycle. The test results are as follows: Table 1 Summary of performance test results for the examples and comparative examples Example 1 Guaiacol 99.8 95.5 92.8 Cyclohexane + Methylcyclohexane 92.6 3.4 95.1 Example 2 Guaiacol 93.4 86.2 84.7 Cyclohexane + Methylcyclohexane 79.1 2.6 90.4 Example 3 Guaiacol 96.8 88.9 80.6 Cyclohexane + Methylcyclohexane 78.0 3.9 88.7 Example 4 soybean oil 97.5 91.3 88.4 C15-C18 long-chain alkanes 86.2 3.3 92.5 Comparative Example 1 Guaiacol 82.1 71.4 69.8 Cyclohexane + Methylcyclohexane 57.3 2.8 89.2 Comparative Example 2 Guaiacol 87.6 74.9 72.1 Cyclohexane + Methylcyclohexane 63.2 1.9 91.0 Comparative Example 3 Guaiacol 90.2 77.6 70.5 Cyclohexane + Methylcyclohexane 63.6 4.0 80.5 Comparative Example 4 Guaiacol 89.5 79.1 76.8 Cyclohexane + Methylcyclohexane 68.7 3.0 90.1 Comparative Example 5 Guaiacol 84.3 52.7 48.9 Cyclohexane + Methylcyclohexane 41.2 3.2 76.4 Comparative Example 6 Guaiacol 61.8 45.6 41.5 Cyclohexane + Methylcyclohexane 25.6 2.1 73.8 Comparative Example 7 Guaiacol 91.1 80.3 73.2 Cyclohexane + Methylcyclohexane 66.7 4.0 83.7

[0027] As can be seen from the comparison of the test results of Example 1 and Comparative Example 1 in the table, after omitting the liquid hydrogen donor, the conversion rate of guaiacol decreased from 99.8% to 82.1%, and the deoxygenation rate decreased from 95.5% to 71.4%. The lack of active surface hydrogen provided by formic acid / formate in the low temperature stage makes it difficult for the substrate to complete the pre-hydrogenation of the aromatic ring and methoxy group in the initial heating stage. The subsequent deep deoxygenation in the medium and high temperature stages can only process the insufficiently activated oxygen-containing intermediates, resulting in a decrease in the hydrogenolysis rate and a decrease in hydrocarbon yield. Comparing the test results of Example 1 and Comparative Example 2 in the table, it can be seen that after omitting the solid chemical hydrogen storage material, the conversion rate drops to 87.6%, the deoxygenation rate drops to 74.9%, and the peak reaction pressure is only 1.9 MPa. In the mid-temperature range, there is a lack of a major source of hydrogen release, and the local hydrogen partial pressure in the system is insufficient. The amount of hydrogen produced by the liquid hydrogen donor is insufficient to cover the consumption in the deep hydrogenation stage. More intermediates remain at the level of methoxycyclohexanol and some deoxygenation products, resulting in a decrease in the yield of completely deoxygenated hydrocarbons. Comparing the test results of Example 1 and Comparative Example 3 in the table, it can be seen that after replacing the microencapsulated sodium borohydride with uncoated sodium borohydride powder, the deoxygenation rate decreased from 95.5% to 77.6%, and the conversion rate retention rate in the 5th cycle decreased from 95.1% to 80.5%. Uncoated sodium borohydride comes into contact with water at a lower temperature and releases hydrogen prematurely, shortening the effective hydrogen supply duration in the mid-temperature range. Furthermore, borate byproducts are more likely to deposit on the catalyst surface, covering Pt-MoO. x Active sites at the interface lead to decreased cycle stability; As can be seen from the comparison of the test results of Example 1 and Comparative Example 4 in the table, after replacing the CO-containing mixed gas with N2, the conversion rate dropped to 89.5% and the deoxygenation rate dropped to 79.1%. The lack of CO participating in the water-gas shift reaction in the high-temperature section means that the system cannot continuously replenish the hydrogen source. The hydrogen supply required for the CO bond breaking stage is insufficient, resulting in an inadequate deep deoxygenation process and an increase in residual products of oxygen-containing cycloalkanols and methoxy groups. Comparing the test results of Example 1 and Comparative Example 5 in the table, it can be seen that after replacing the catalyst with Pt / TiO2, the deoxygenation rate decreased from 95.5% to 52.7%, and the hydrocarbon selectivity decreased to 48.9%. Although the Pt sites can promote the decomposition of formic acid, the activation of sodium borohydride, and the dissociation of hydrogen, the system lacks MoO2. x With the availability of oxygen vacancies and Lewis acid sites, CO bonds in the substrate are difficult to be effectively adsorbed and polarized, and the reaction tends to remain at the hydrogenation stage rather than the deoxygenation stage, thus significantly reducing the fully deoxygenated products. As can be seen from the comparison of the test results of Example 1 and Comparative Example 6 in the table, replacing the catalyst with MoO2... x After applying TiO2, the conversion rate decreased from 99.8% to 61.8%, and the hydrocarbon yield decreased to 25.6%; MoO x The sites can adsorb oxygen-containing groups, but without Pt sites, the dehydrogenation of liquid hydrogen donors, the activation of solid hydrogen storage materials and the hydrogen dissociation ability are significantly weakened. The active hydrogen formation rate is insufficient, and the intermediates adsorbed on the oxygen-loving sites are difficult to be dehydrogenated in time, resulting in a simultaneous decrease in substrate conversion and deoxygenation. Comparing the test results of Example 1 and Comparative Example 7 in the table, it can be seen that after canceling the three-stage temperature program, the conversion rate dropped to 91.1%, the deoxygenation rate dropped to 80.3%, and the peak pressure rose to 4.0 MPa. Directly raising the temperature will cause the decomposition of formic acid, the release of hydrogen from sodium borohydride, and the participation of CO in the conversion reaction to occur superimposed in a shorter temperature range. The hydrogen supply rate is not matched with the hydrogen consumption of the substrate at each stage, and some hydrogen is released in the non-effective reaction range, resulting in increased pressure fluctuations. At the same time, the intermediate did not undergo a stable low-temperature pre-hydrogenation and medium-temperature deep saturation process, which led to a decrease in the selectivity of subsequent hydrogen deoxygenation. The test results from Examples 1 to 4 show that, within the range defined above in this invention, adjusting the catalyst preparation parameters, microcapsule preparation parameters, and programmed temperature conditions can all yield high conversion rates and deoxygenation rates. Example 2 uses lower limit parameters, resulting in relatively low active site formation and medium-high temperature hydrogen supply intensity, thus leading to a decrease in performance. Example 3 uses upper limit boundary parameters, which can maintain a high conversion rate, but the higher temperature and longer holding time will increase the proportion of side reactions and reduce hydrocarbon selectivity. Example 4 uses magnesium nickel hydride microcapsules instead of sodium borohydride microcapsules, and still maintains a high deoxygenation level, indicating that the process is replaceable for solid hydrogen storage materials. Overall, Example 1 achieves a more balanced result in terms of conversion rate, deoxygenation rate, hydrocarbon yield, pressure control and cycle retention rate.

[0028] The above are merely specific embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any conventional modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A catalyst, characterized in that, The catalyst comprises a support and platinum-containing and molybdenum-containing components loaded on the support; wherein the support comprises titanium dioxide; the mass fraction of the platinum-containing component in the catalyst is 0.5 wt%-2.0 wt%, and the mass fraction of the molybdenum-containing component is 5.0 wt%-10.0 wt%, the mass fractions of the aforementioned platinum-containing and molybdenum-containing components being calculated as elemental platinum and molybdenum oxide, respectively; the catalyst is prepared by a method comprising the following steps: mixing a platinum source solution and a molybdenum source solution, adding an acidic adjuster to adjust the pH value to 2.0-3.0 to prepare a mixed impregnation solution; loading the mixed impregnation solution onto the support using an equal-volume co-impregnation method, followed by drying and calcination to prepare an oxidized precursor; and subjecting the oxidized precursor to a reducing atmosphere by heating and reduction to prepare the catalyst. The platinum source solution includes chloroplatinic acid solution, and the molybdenum source solution includes ammonium metamolybdate solution; the support includes anatase titanium dioxide; and the acid regulator includes dilute nitric acid. The drying process parameters include: drying under vacuum at a temperature of 70℃-90℃ for 10h-14h; and the calcination process parameters include: calcining in air at a temperature of 400℃-500℃ for 3h-5h; and the temperature-increasing reduction process parameters include: heating to 350℃-400℃ in a hydrogen-containing reducing atmosphere using a programmed temperature increase method, and reacting for 2h-4h.

2. An in-situ catalytic deoxygenation and hydrogenation method, characterized in that, The process includes the following steps: mixing the reaction substrate, reaction solvent, liquid hydrogen donor, solid chemical hydrogen storage material, and catalyst in a reactor equipped with a back pressure regulating valve; performing gas replacement treatment; and then introducing a mixed gas containing carbon monoxide; subjecting the reactor to programmed temperature increase to carry out a hydrodeoxygenation reaction to prepare a hydrodeoxygenation product; wherein the catalyst is the catalyst described in claim 1. The reaction substrate is one or more of a biomass oxygen-containing model and bio-oils; wherein the biomass oxygen-containing model includes guaiacol; the bio-oils include soybean oil; and the reaction solvent includes a mixed solvent of water and dodecane; and the liquid hydrogen donor includes a buffer solution composed of formic acid and alkali metal formate; and the carbon monoxide-containing mixed gas is biomass pyrolysis gas or simulated biomass pyrolysis gas. The solid-state chemical hydrogen storage material includes microcapsules, each microcapsule comprising a wall material and a core material encapsulated by the wall material; wherein the wall material comprises one or more of a phase change wax and a polymer; the polymer is an ethylene-vinyl acetate copolymer; and the core material comprises sodium borohydride or nano-magnesium nickel hydride.

3. The in-situ catalytic deoxygenation and hydrogenation method according to claim 2, characterized in that, The in-situ catalytic deoxygenation and hydrogenation method has one or more of the following characteristics: (1) In the mixed solvent of water and dodecane, the volume ratio of water to dodecane is 1:(0.8-1.2); (2) In the buffer solution composed of formic acid and alkali metal formate, the molar ratio of formic acid to formate is 1:(0.8-1.2). (3) In the mixed gas containing carbon monoxide, the volume fraction of carbon monoxide is 25%-35%, the volume fraction of carbon dioxide is 15%-25%, the volume fraction of nitrogen is 45%-55%, and the sum of the volume fractions of each component is 100%; (4) The amount of catalyst added is 3wt%-8wt% of the mass of the reaction substrate.

4. The in-situ catalytic deoxygenation and hydrogenation method according to claim 2, characterized in that, The preparation method of the microcapsules includes the following steps: heating the wall material to 145℃-160℃ to completely melt it, adding the core material, and stirring at a speed of 500rpm-1000rpm for 10min-30min, then adding a silicone oil dispersion medium containing emulsifier for emulsification treatment, and then cooling and solidifying to room temperature at a cooling rate of 2℃ / min-5℃ / min, and finally filtering and drying under vacuum at 40℃-60℃ for 12h-24h.

5. The in-situ catalytic deoxygenation and hydrogenation method according to claim 2, characterized in that, The programmed temperature rise steps sequentially include a first-stage reaction, a second-stage reaction, and a third-stage reaction; the process parameters for the first-stage reaction include: a temperature of 80℃-120℃ and a time of 0.5h-2h; the process parameters for the second-stage reaction include: a temperature of 120℃-180℃ and a time of 1h-2h; the process parameters for the third-stage reaction include: a temperature of 180℃-280℃ and a time of 1.5h-3h.

6. The in-situ catalytic deoxygenation and hydrogenation method according to claim 5, characterized in that, The in-situ catalytic deoxygenation and hydrogenation method has one or more of the following characteristics: (1) The heating rate of the first stage reaction is 2℃ / min-5℃ / min; (2) The charging pressure of the mixed gas containing carbon monoxide is 0.5 MPa-1.0 MPa; (3) During the hydrodeoxygenation reaction, the pressure inside the reactor is controlled by the back pressure regulating valve, and the set threshold of the back pressure regulating valve is 3.0MPa-5.0MPa; (4) After the hydrodeoxygenation reaction is completed, the process further includes: cooling the reactor with a cold trap, collecting the gas phase components through a membrane separation device, and allowing the reaction liquid to stand and separate into layers to obtain an organic phase and an aqueous phase, wherein the organic phase is the hydrodeoxygenation product, and centrifuging the aqueous phase and the interface between the two phases to recover the catalyst.