High-thermal-conductivity foam metal supported catalyst as well as preparation method and application thereof

Abstract

The invention discloses a high-thermal-conductivity foam metal supported catalyst as well as a preparation method and application thereof. The supported catalyst comprises a foam metal carrier, an active metal component and an auxiliary agent, wherein the active metal component and the auxiliary agent are supported on the foam metal carrier; the foam metal carrier comprises one of foam nickel, foam copper and foam titanium; the active metal components comprise at least two of Cu, Fe, Ni, Mo, Mn, Rh, Pt and Pd; the auxiliary agent comprises one or more than two of La, Mg, Zr and Ce. The high-thermal-conductivity foam metal supported catalyst disclosed by the invention can be used for a heat-work conversion reactor of a high-speed aircraft, and can be used for rapidly catalyzing a multi-component alcohol and water system to generate a heat-absorbing chemical reforming reaction by strengthening heat conduction and constructing an efficient active center; harmful aerodynamic heat is absorbed, high-temperature and high-pressure small-molecule gas (hydrogen, carbon monoxide and the like) is generated and used for doing work to generate thrust, and aerodynamic heat management and heat-work conversion of the high-speed aircraft are achieved.

Description

Technical Field

[0001] The present invention relates to the field of catalytic technology, and more specifically, to a high thermal conductivity foam metal supported catalyst and a preparation method and application thereof. Background Art

[0002] High-speed aircraft have become the key to international strategic games with their advantages of rapid response, rapid strike, and easy penetration. When a high-speed aircraft flies at high speed, the temperature of its outer wall and nearby areas rises rapidly due to shock wave compression, viscous friction, etc. In order to ensure that the internal components work normally within the allowable temperature range and maintain their aerodynamic shape, effective structural thermal protection design must be carried out. Thermal protection technology can be mainly divided into passive thermal protection technology and active thermal protection technology. Passive thermal protection using thermal protection materials for insulation or ablative materials for phase change and heat absorption is the most widely used aerodynamic heat treatment measure. This type of thermal protection technology has a relatively simple structure, but the preparation process is complex and the cost is high. When the ablative thermal protection system is flying at high speed, the material will gradually be ablated as the temperature rises, which can easily change the overall aerodynamic shape and cause accidents. At the same time, due to the weak heat absorption capacity of the passive thermal protection system, the thickness and weight of the required materials in long-flight applications are large, which seriously compresses the payload of the aircraft.

[0003] Relatively speaking, active thermal protection uses cooling fluids to remove or block heat from the structure through various cooling forms. Compared with passive thermal protection, active thermal protection has the advantages of strong cooling capacity, ability to withstand long-term heating of high-density heat flow, and closed-loop temperature control. Active thermal protection technology is mainly divided into two categories, namely sweat cooling and convection cooling. The commonly used cooling fluid for sweat cooling is water. It draws on the way organisms sweat to dissipate heat, uses the latent heat of vaporization of water to absorb heat and form a thermal insulation barrier, but the system reliability is poor. Convection cooling is often used in aerospace vehicles or aviation vehicles. Generally, circulating liquid hydrocarbon fuels are used as coolants, and the physical heat capacity of the fuel is used to remove heat from the surface of the structure. Due to the limitation of fuel coking, this heat absorption mode is only suitable for supersonic flight at speeds below Mach 5.

[0004] In recent years, with the further improvement of high-speed aircraft performance, especially the development of long-endurance high-speed aircraft, its aerodynamic thermal environment has become more complex and harsh. Therefore, it is of great significance to develop an efficient and reliable method to absorb the aerodynamic heat of high-speed aircraft.

[0005] In view of the above difficulties, based on experimental and theoretical research, it is found that when a mixed solution of alcohol and water is used as a cooling medium for an active thermal protection system, it can absorb a large amount of aerodynamic heat through a physical vaporization reaction. In particular, when a suitable catalyst is contained in the system, it can catalyze a strongly endothermic reforming reaction of alcohol and water. Taking ethanol and water solution as an example, after vaporization, a reforming reaction can generate hydrogen and carbon monoxide (Equation 1), and the gas volume increases three times, and the heat absorbed per mole of fluid reaches 256.8kJ. When the aerodynamic heat temperature reaches 600℃, the heat absorption of pure water is only 3.6MJ / Kg, while the total amount of physical and chemical heat absorption of a mixed solution of ethanol and water under the same conditions can reach more than 6.2MJ / Kg. In addition, the small molecular gases (such as hydrogen and carbon monoxide) produced can be used to do external work. Therefore, based on this green working medium, not only can the heat absorption capacity of the system be improved, but also aerodynamic heat can be converted into chemical energy to realize waste heat utilization, thereby reducing the thickness of the aircraft insulation layer, increasing the system payload, and improving the maneuverability of the aircraft.

[0006] At present, a large number of catalysts for alcohol-water reactions have been reported (Industrial & Engineering Chemistry Research 2021, 60, 89; Chemical Engineering Journal, 2006, 117, 39). However, they are mainly limited to the field of hydrogen production, such as methanol steam reforming to produce hydrogen (Equation 2) and ethanol steam reforming to produce hydrogen (Equation 3). In order to increase the hydrogen production, a large amount of water is added to the raw materials to enhance the water vapor shift reaction (Equation 4; exothermic), resulting in the chemical reaction not only having a lower heat absorption capacity than ethanol reforming to produce synthesis gas (Equation 1) and methanol decomposition reaction (Equation 5), but also a decrease in the gas volume expansion effect, resulting in a decrease in the system's work capacity. In addition, the traditional reforming hydrogen production reaction (reaction of volume increase) is generally carried out at atmospheric pressure to increase the reaction rate and promote hydrogen generation. For the heat-to-work conversion system, in order to improve the work effect, the chemical reaction must be carried out under high pressure conditions (the higher the pressure, the greater the ability to do external work). In the reforming reaction products, H2 / CO or H2 / CO2 coexist in large quantities, and under high pressure conditions, a volume reduction and highly exothermic methanation reaction is prone to occur (Equations 6 and 7), thereby reducing the system's heat absorption and work efficiency.

[0007] In addition to the difference in reaction conditions, when the type of alcohol is changed, the requirements for the catalyst will also change significantly. For example, for methanol steam reforming reaction (Nature Catalysis, 2022, 5, 99), the main active components of its industrial application catalyst are Cu / Zn / Al, and the working temperature is mainly between 180-300°C; while for ethanol water reforming catalysts, literature research mainly focuses on Ni-based catalysts (Renewable and Sustainable Energy Reviews, 2023, 175, 113184), and due to the high stability of CC bonds, the reaction temperature is generally between 350-600°C. For heat-to-work conversion systems, in order to broaden their effective working temperature range, the required alcohol-water working fluid is often a multi-component composite system, such as promoting the absorption of low-temperature aerodynamic heat through low-carbon alcohol-water reforming in the working fluid, and improving the total heat absorption capacity of the endothermic working fluid through multi-carbon alcohol-water reforming. Therefore, the traditional reforming catalysts for hydrogen production from two-component alcohol-water systems (methanol / water, ethanol / water) can no longer meet the requirements of heat-to-power conversion systems based on multi-component alcohol-water systems (such as a four-component system of methanol / ethanol / isopropanol / water).

[0008] In particular, due to the endothermic characteristics of the alcohol-water reaction, catalysts based on traditional carriers (such as alumina) will form local cold spots during the reaction, causing the reaction rate to drop rapidly. The reason is that the aerodynamic heat is transferred slowly from the surface of the reactor (metal material) to the inside, thus limiting the rapid absorption of aerodynamic heat. Therefore, strengthening the heat transfer of the catalytic bed is the key to increasing the heat-to-work conversion efficiency of high-speed aircraft.

[0009] In summary, the development of new catalysts suitable for high-speed aircraft heat-to-power conversion systems has important application value.

[0010] Summary of the invention

[0011] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a high thermal conductivity foam metal supported catalyst and its preparation method and application. The high thermal conductivity foam metal supported catalyst of the present invention can be used in a high-speed aircraft heat-to-work conversion reactor. By enhancing heat conduction and constructing efficient active centers, it can quickly catalyze the endothermic chemical reforming reaction of a multi-component alcohol and water system, thereby absorbing "harmful" aerodynamic heat and generating high-temperature and high-pressure small molecule gases (hydrogen, carbon monoxide, etc.) for doing work to generate thrust, thereby realizing aerodynamic thermal management and heat-to-work conversion of high-speed aircraft.

[0012] To achieve the above object, the technical solution of the present invention is as follows:

[0013] A high thermal conductivity foam metal supported catalyst, the supported catalyst comprising a foam metal carrier and an active metal component and an additive supported on the foam metal carrier; the foam metal carrier comprises one of foam nickel, foam copper and foam titanium; the active metal component comprises at least two of Cu, Fe, Ni, Mo, Mn, Rh, Pt and Pd; the additive comprises one or more of La, Mg, Zr or Ce.

[0014] Optionally, the active metal component is a combination containing at least Cu and at least one of Fe, Ni, Mo, Mn, Rh, Pt, and Pd; based on the total molar content of total active metal ions, the molar content of each metal element in the active metal component accounts for no less than 20% of the total molar content of the metal.

[0015] Optionally, when the active metal component is a combination containing at least Cu and at least one of Fe, Ni, Mo, Mn, Rh, Pt, and Pd, the additive is Zr and / or Ce.

[0016] Optionally, the active metal component is a combination containing at least Cu, Rh, and at least one of Fe, Ni, Mo, Mn, Pt and Pd. Preferably, the active metal component is CuRhPd. Based on the total molar content of total active metal ions, the molar content of each metal element in the active metal component accounts for no less than 25% of the total molar content of the metal.

[0017] Optionally, when the active metal component is CuRhPd, the auxiliary agent is Zr and / or Ce.

[0018] Optionally, in the supported catalyst, the mass of the active metal component is 1% to 20% of the total mass of the supported catalyst, and the mass of the auxiliary agent is 1% to 10% of the total mass of the supported catalyst.

[0019] Optionally, the pore size of the foam metal carrier is 0.1 mm to 1.2 mm; the porosity of the foam metal carrier is 40% to 90%.

[0020] The present invention also discloses a method for preparing the above-mentioned high thermal conductivity foam metal supported catalyst, comprising the following steps:

[0021] (1) dissolving an active metal component precursor and an auxiliary agent precursor in water, adding a complexing agent and mixing them to obtain an impregnation solution;

[0022] (2) adding a foamed metal carrier to the impregnation solution for impregnation, then taking it out and drying it, and then quickly placing the precursor obtained after drying into a tubular furnace preheated to 400° C. to 600° C., and rapidly heating the precursor to a set temperature within 0 s to 10 s in an oxidizing atmosphere and / or a reducing atmosphere, keeping the temperature for 10 min to 120 min, cooling it to room temperature and then taking it out of the furnace to obtain the high thermal conductivity foamed metal supported catalyst.

[0023] Optionally, in step (1), the active metal component precursor is a soluble salt or acid of the active metal component; the auxiliary agent precursor is a soluble salt or acid of the auxiliary agent; the complexing agent includes one or more of glycine, glycerol, citric acid and ethylene glycol; the ratio of the total amount of metal ions in the impregnation solution to the amount of complex is 1:(1 to 6); and the mixing temperature is 60°C to 80°C.

[0024] Optionally, in the step (2), the impregnation time is 10 min to 30 min; the drying temperature is 80°C to 120°C; the calcination temperature is 400°C to 600°C, preferably the calcination temperature is 400°C to 450°C; the impregnation is multiple impregnations, and the number of multiple impregnations is 1 to 5 times; the multiple impregnation method includes: drying and calcining the product after each impregnation before the next impregnation.

[0025] The present invention also discloses an application of the high thermal conductivity foam metal supported catalyst as described above, or the high thermal conductivity foam metal supported catalyst prepared by the above preparation method in catalyzing alcohol-water reforming reaction to produce synthesis gas, characterized in that the application is used in a high-speed aircraft heat-to-power conversion system.

[0026] Optionally, the alcohol aqueous solution includes an aqueous solution containing at least one of methanol, ethanol, ethylene glycol, isopropanol and n-propanol.

[0027] Optionally, the temperature of the alcohol-water reforming reaction is 200°C to 800°C, preferably 300°C to 600°C; the reaction pressure of the alcohol-water reforming reaction is 5 bar to 20 bar, preferably 5 bar to 10 bar.

[0028] Optionally, the alcohol aqueous solution includes an aqueous solution containing at least two of methanol, ethanol, ethylene glycol and isopropanol; the mass content of a single alcohol component in the alcohol aqueous solution is ≥10%, and the total mass fraction of alcohol in the alcohol aqueous solution is 40% to 70%.

[0029] Optionally, the high-speed aircraft heat-to-work conversion system includes: a distributed liquid cooling plate 1, a first solenoid valve 2, a heat-to-work conversion plate 3, a gas-liquid storage tank 4, a second solenoid valve 5, a thrust engine 6, a third solenoid valve 7, an oxygen supplementation system 8, and a fourth solenoid valve 9; the heat-to-work conversion plate 3 is a flat plate structure, loaded with a loaded high-entropy metal catalyst as described above, or a loaded high-entropy metal catalyst prepared by the above-mentioned preparation method; the distributed liquid cooling plate 1 is connected to the inlet of the heat-to-work conversion plate 3 through the first solenoid valve 2, the outlet of the heat-to-work conversion plate 3 is connected to the inlet of the gas-liquid storage tank 4, the first outlet of the gas-liquid storage tank 4 is connected to the inlet of the thrust engine 6 through the second solenoid valve 5, the second outlet of the gas-liquid storage tank 4 is connected to the inlet of the distributed liquid cooling plate 1 through the third solenoid valve 7, and the inlet of the oxygen supplementation system 8 is connected to the inlet of the thrust engine 6 through the fourth solenoid valve 9.

[0030] Optionally, the method for using the high-speed aircraft heat-to-work conversion system includes: the liquid cooling medium in the distributed liquid cooling plate 1 is heated and vaporized by aerodynamic heat or heat dissipation of the carrier, and then enters the heat-to-work conversion plate 3 through the first solenoid valve 2; under the action of high-temperature aerodynamic heat and the loaded high-entropy metal catalyst, the vaporized liquid cooling medium undergoes a chemical endothermic reaction and produces high-pressure gas small molecules; the high-pressure gas small molecules and unreacted liquid cooling medium enter the gas-liquid storage tank 4 through a pipeline; the high-pressure gas small molecules can be discharged through the first outlet of the gas-liquid storage tank 4 through the second solenoid valve 5 and the thrust engine 6, and then perform work to generate thrust; the oxygen supplement module 8 mixes the oxidizing atmosphere and the discharged high-pressure gas small molecules through the fourth solenoid valve 9, thereby realizing dual-component work and increasing the system thrust; the unreacted liquid cooling medium can be passed through the second outlet of the gas-liquid storage tank 4 through the third solenoid valve 7 into the distributed liquid cooling plate 1 for recycling.

[0031] Optionally, the high-speed aircraft heat-to-work conversion system includes: a distributed liquid cooling plate and a heat-to-work conversion plate, the distributed liquid cooling plate is connected to the heat-to-work conversion plate via a liquid flow pump, the heat-to-work conversion plate is loaded with a loaded high-entropy metal catalyst as described above, or a loaded high-entropy metal catalyst prepared by the above-mentioned preparation method, the liquid flow pump can control the flow rate of the working fluid delivered from the distributed liquid cooling plate to the heat-to-work conversion plate, and thermal heating is simulated by an infrared heating furnace.

[0032] Implementing the embodiments of the present invention will have the following beneficial effects:

[0033] The high thermal conductivity foam metal supported catalyst provided by the present invention uses foam metal as a carrier. Compared with traditional carrier (such as metal oxides such as aluminum oxide and silicon oxide) supported metal catalysts, the catalyst of the present invention can quickly transfer the aerodynamic heat outside the reactor to the inside of the reactor due to the high thermal conductivity of the foam metal, so that the catalyst bed maintains a relatively high temperature, thereby significantly improving the heat-to-work conversion efficiency.

[0034] The high thermal conductivity foam metal supported catalyst provided by the present invention greatly improves the activity of the catalyst by utilizing the combination of single atoms of different elements on the carrier; in particular, the synergistic effect of the active metal components Cu and Rh can obtain good heat absorption performance.

[0035] Compared with the traditional method of simple impregnation and slow calcination, the present invention uses a rapid temperature rise calcination method to make the mixing of multiple active components more uniform and more active. The strategy of multiple impregnation and multiple calcination can effectively increase the active metal loading, strengthen the interaction between the active metal and the foam carrier, and improve the catalyst stability.

[0036] The supported catalyst of the present invention can meet the requirements of the heat-work conversion system of a multi-component alcohol-water system (such as a four-component system of methanol / ethanol / isopropanol / water).

[0037] Compared with the traditional passive heat insulation method, the heat-to-work conversion system based on the catalyst of the present invention belongs to the active heat protection technology, which has the advantages of strong cooling capacity, being able to withstand long-term heating of high-density heat flow, and realizing closed-loop temperature control.

[0038] Compared with the active heat insulation method of water sweating, the heat-to-work conversion system based on the catalyst of the present invention absorbs heat by coupling physical and chemical reactions. The theoretical maximum heat absorption capacity of the system is more than doubled (>6MJ / kg) compared with the heat absorption by water sweating (~3MJ / kg), which effectively enhances the heat absorption performance of the system and can generate thrust to do work. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The heat absorption capacity of methanol in Example 1 of the present invention is compared with the heat absorption performance of water.

[0040] Figure 2 The heat absorption performance of ethanol steam reforming in Example 2 of the present invention is compared with that of water.

[0041] Figure 3 The heat absorption performance of isopropanol steam reforming in Example 3 of the present invention is compared with that of water.

[0042] Figure 4 This is a graph showing how the components of the methanol decomposition equilibrium products change with temperature under a pressure of 2 MPa in Example 4 of the present invention.

[0043] Figure 5Schematic diagram of the high-speed aircraft heat-to-power conversion system of embodiment 21 of the present invention.

[0044] Figure 6 This is a schematic diagram of the structure of the heat-to-work conversion plate of Example 21 of the present invention.

[0045] Figure 7 This is a schematic diagram of heat transfer of high thermal conductivity foam metal supported catalyst in Example 21 of the present invention.

[0046] Among them: 1. distributed liquid cooling plate, 2. first solenoid valve, 3. heat-to-work conversion plate, 4. gas-liquid storage tank, 5. second solenoid valve, 6. thrust engine, 7. third solenoid valve, 8. oxygen supplementation system, 9. fourth solenoid valve. DETAILED DESCRIPTION

[0047] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0048] Unless otherwise specified, the raw materials and catalysts in the examples of this application were purchased through commercial channels.

[0049] Working fluid heat sink test method:

[0050] The current heating reaction is used to evaluate the heat sink of the working fluid, and the energy conservation method is used to calculate the heat sink of the endothermic process.

[0051] Q sink =Q in -Q loss (Equation 8)

[0052] ΔH sink =Q sink / m feed (Equation 9)

[0053] Q sink is the heat absorption power of the working fluid (kW), Q in is the input power (kW) on the reactor during steady-state operation, Q loss is the heat dissipation power of the reactor and electrodes (kW), ΔH sink is the total heat sink generated by the heat absorbing medium (MJ kg -1 ), m feed is the feed mass rate of the endothermic medium (g·s -1 ).

[0054] Example 1

[0055] The maximum theoretical heat sink of methanol was studied by thermodynamic calculation, where the initial temperature of methanol was room temperature (25°C) and the heat absorbed by its complete decomposition into H2 and CO (Equation 2) at different temperatures was as follows: Figure 1 shown.

[0056] Example 2

[0057] Calculate the maximum theoretical heat sink of an ethanol / water solution, where the molar ratio of ethanol to water is 1:1 and the initial temperature is room temperature (25°C). The heat absorbed by the solution at different temperatures for complete decomposition into H2 and CO (Equation 3) is as follows: Figure 2 shown.

[0058] Example 3

[0059] The maximum theoretical heat sink of an isopropanol / water solution, where the molar ratio of isopropanol to water is 1:2 and the initial temperature is room temperature (25°C), is calculated as follows: Figure 3 shown.

[0060] Example 4

[0061] Through thermodynamic calculation, the product components of methanol decomposition reaction at different temperatures when the reaction pressure is 2Mpa are studied. Figure 4 shown.

[0062] according to Figure 1-Figure 4 It can be seen that methanol decomposition reaction is more active. At about 200°C, its theoretical maximum heat sink (decomposition to produce hydrogen and carbon monoxide) can exceed the physical heat absorption of water. For ethanol and isopropanol, the theoretical maximum heat sink is equivalent to the physical heat absorption of water at about 250°C and 300°C, respectively. In addition, for the three alcohols, their theoretical maximum heat sink increases linearly with temperature after 450°C, indicating that their theoretical conversion rates all reach 100%. However, from the maximum heat sink value, it can be seen that with the increase of the number of carbon atoms, the maximum heat sink value increases significantly. At 500°C, the methanol decomposition heat sink is 5.4MJ / kg, the ethanol / water maximum heat sink is 6.6MJ / kg, and the isopropanol / water maximum heat sink is 7.0MJ / kg. It can be seen that in order to make the endothermic working fluid present a larger heat sink in a wider temperature range, its formula needs to be optimized.

[0063] In addition, when the reaction pressure is high (2MPa), it can be seen from the equilibrium components of methanol decomposition that its low-temperature products are mainly CH4, H2O and CO2. Only when the temperature is high (>500℃) can H2 and CO be produced. Therefore, it is further explained that regulating the reaction path through the catalyst is the key to improving the chemical endothermic capacity of alcohol-water working fluid.

[0064] Example 5

[0065] Preparation of CuNi(Zr) metal catalyst supported on nickel foam:

[0066] First, copper nitrate and nickel nitrate are used as metal precursors, and the molar ratio of the two metals is 1:1. They are dissolved in deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. In addition, zirconium nitrate is added to the solution, and the molar ratio of Zr to Cu is 1:1. Then glycine is added to the solution to obtain a metal ion precursor solution, wherein the molar ratio of glycine to total metal ions is 1:1, that is, the concentration of glycine in the solution is 0.15 mol / L. The beaker containing the above solution is placed in a 60°C water bath, slowly evaporated until the solution is viscous, and then the foamed Ni carrier is immersed in the above viscous solution, taken out after stabilization for 10 minutes, and swept with compressed air for 2 minutes, and then rapidly heated and roasted at 450°C in air for 10 minutes, and then rapidly heated and reduced at 400°C with hydrogen for 30 minutes, and then stopped heating and naturally cooled to room temperature. The steps of impregnation, air purging and calcination were repeated 4 times until the active metal loaded on the foam metal reached 10%. The catalyst was named 10-CuNi(Zr) / Ni-P.

[0067] Example 6

[0068] Preparation of CuMo(Zr) metal catalyst supported on nickel foam:

[0069] The only difference between this embodiment and embodiment 5 is that the metal precursors are copper nitrate and molybdenum nitrate, the molar ratio of the two metals is 1:1, and the total concentration in the solution is 0.1 mol / L.

[0070] The catalyst 10-CuMo(Zr) / Ni-P of this example was obtained according to the preparation method of Example 5.

[0071] Example 7

[0072] Preparation of CuFe(Zr) metal catalyst supported on nickel foam:

[0073] The only difference between this embodiment and embodiment 5 is that the metal precursors are copper nitrate and iron nitrate, the molar ratio of the two metals is 1:1, and the total concentration in the solution is 0.1 mol / L.

[0074] The catalyst 10-CuFe(Zr) / Ni-P of this example was obtained according to the preparation method of Example 5.

[0075] Example 8

[0076] Preparation of CuMn(Zr) metal catalyst supported on nickel foam:

[0077] The only difference between this embodiment and embodiment 5 is that the metal precursors are copper nitrate and manganese nitrate, the molar ratio of the two metals is 1:1, and the total concentration in the solution is 0.1 mol / L.

[0078] The catalyst 10-CuMn(Zr) / Ni-P of this example was obtained according to the preparation method of Example 5.

[0079] Example 9

[0080] Preparation of CuPd(Zr) metal catalyst supported on nickel foam:

[0081] The only difference between this embodiment and embodiment 5 is that the metal precursors are copper nitrate and palladium chloride, the molar ratio of the two metals is 1:1, and the total concentration in the solution is 0.1 mol / L.

[0082] The catalyst 10-CuPd(Zr) / Ni-P of this example was obtained according to the preparation method of Example 5.

[0083] Example 10

[0084] Preparation of CuPt(Zr) metal catalyst supported on nickel foam:

[0085] The only difference between this embodiment and embodiment 5 is that the metal precursors are copper nitrate and chloroplatinic acid, the molar ratio of the two metals is 1:1, and the total concentration in the solution is 0.1 mol / L.

[0086] The catalyst 10-CuPt(Zr) / Ni-P of this example was obtained according to the preparation method of Example 5.

[0087] Embodiment 11

[0088] Preparation of CuRh(Zr) metal catalyst supported on nickel foam:

[0089] The only difference between this embodiment and embodiment 5 is that the metal precursors are copper nitrate and rhodium chloride, the molar ratio of the two metals is 1:1, and the total concentration in the solution is 0.1 mol / L.

[0090] The catalyst 10-CuRh(Zr) / Ni-P of this example was obtained according to the preparation method of Example 5.

[0091] Example 12

[0092] Preparation of CuRh(La) metal catalyst supported on nickel foam:

[0093] The only difference between this embodiment and embodiment 11 is that the auxiliary agent precursor is lanthanum nitrate, and the molar ratio of La to Cu is 1:1.

[0094] The catalyst 10-CuRh(La) / Ni-P of this example was obtained according to the preparation method of Example 11.

[0095] Example 13

[0096] Preparation of CuRh(Mg) metal catalyst supported on nickel foam:

[0097] The only difference between this embodiment and embodiment 11 is that the auxiliary agent precursor is magnesium nitrate, and the molar ratio of Mg to Cu is 1:1.

[0098] The catalyst 10-CuRh(Mg) / Ni-P of this example was obtained according to the preparation method of Example 11.

[0099] Embodiment 14

[0100] Preparation of CuRh(Ce) metal catalyst supported on nickel foam:

[0101] The only difference between this embodiment and embodiment 11 is that the auxiliary agent precursor is cerium nitrate, and the molar ratio of Ce to Cu is 1:1.

[0102] The catalyst 10-CuRh(Ce) / Ni-P of this example was obtained according to the preparation method of Example 11.

[0103] Embodiment 15

[0104] Preparation of CuRh(Ce) metal catalyst supported on copper foam:

[0105] The only difference between this embodiment and Embodiment 14 is that the foamed nickel carrier is replaced by a foamed copper carrier.

[0106] The catalyst 10-CuRh(Ce) / Cu-P of this example was obtained according to the preparation method of Example 14.

[0107] Example 16

[0108] Preparation of CuRh(Ce) metal catalyst supported on titanium foam:

[0109] The only difference between this embodiment and Embodiment 14 is that the nickel foam carrier is replaced by a titanium foam carrier.

[0110] The catalyst 10-CuRh(Ce) / Ti-P of this example was obtained according to the preparation method of Example 14.

[0111] Embodiment 17

[0112] Preparation of CuRhPd(Ce) metal catalyst supported on nickel foam:

[0113] The only difference between this embodiment and Embodiment 14 is that the metal precursors are copper nitrate, rhodium chloride and palladium chloride, the molar ratio of the three metals is 1:1:1, and the total concentration in the solution is 0.1 mol / L.

[0114] The auxiliary agent precursor is cerium nitrate, the molar ratio of Ce to Cu is 1.5:1, and the molar ratio of Ce to the total amount of active metal is 1:2, which is consistent with Example 14.

[0115] The catalyst 10-CuRhPd(Ce) / Ni-P of this example was obtained according to the preparation method of Example 14.

[0116] Embodiment 18

[0117] Preparation of CuRhPd(Ce)-HR metal catalyst supported on nickel foam:

[0118] The only difference between this embodiment and embodiment 17 is that the reduction temperature is changed to 600°C.

[0119] The catalyst 10-CuRhPd(Ce)-HR / Ni-P of this example was obtained according to the preparation method of Example 17.

[0120] Embodiment 19

[0121] Preparation of CuRhPd(Ce)-HO metal catalyst supported on nickel foam:

[0122] The only difference between this embodiment and embodiment 17 is that the oxidation temperature is changed to 600°C.

[0123] The catalyst 10-CuRhPd(Ce)-HO / Ni-P of this example was obtained according to the preparation method of Example 17.

[0124] Embodiment 20

[0125] Preparation of CuRhPd(Ce)-C metal catalyst supported on nickel foam:

[0126] The only difference between this embodiment and Embodiment 17 is that the heating rate of the oxidation and reduction roasting steps is changed to 2°C / min.

[0127] The catalyst 10-CuRhPd(Ce)-S / Ni-P of this example was obtained according to the preparation method of Example 17.

[0128] Comparative Example 1

[0129] Preparation of Cu metal catalyst supported on nickel foam (10-Cu(Ce) / Ni-P):

[0130] The only difference between this comparative example and Example 15 is that the metal precursor is only copper nitrate.

[0131] The catalyst 10-Cu(Ce) / Ni-P of this comparative example was obtained according to the preparation method of Example 5.

[0132] Comparative Example 2

[0133] Preparation of Cu metal catalyst supported on nickel foam (10-CuRh / Ni-P):

[0134] The only difference between this comparative example and Example 15 is that no cerium nitrate is added.

[0135] The catalyst 10-CuRh / Ni-P of this comparative example was obtained according to the preparation method of Example 5.

[0136] Comparative Example 3

[0137] Preparation of Cu metal catalyst supported on nickel foam (10-Cu / Ni-P):

[0138] The only difference between this comparative example and Example 15 is that the metal precursor is only copper nitrate and no cerium nitrate is added.

[0139] The catalyst 10-Cu / Ni-P of this comparative example was obtained according to the preparation method of Example 5.

[0140] Comparative Example 4

[0141] Preparation of CuRh(Ce) metal catalyst supported on alumina:

[0142] The only difference between this comparative example and Example 15 is that the carrier is an alumina carrier.

[0143] The specific preparation method is as follows: the metal precursor is changed to copper nitrate and rhodium chloride, the molar ratio of the two metals is 1:1, and the total concentration in the solution is 0.1 mol / L; in addition, cerium nitrate is added to the solution, and the molar ratio of Ce to Cu is 1:1; 15 mL of the above solution is taken, and then 9 g of alumina carrier is added, and the beaker containing the above solution is placed in a 60°C water bath, and stirred until the solution is completely evaporated, and then the powder is calcined at 350°C in air for 60 minutes, and then reduced with hydrogen at 400°C for 30 minutes, and the heating is stopped, and naturally cooled to room temperature, and the above operation is repeated 4 times to prepare a catalyst with a CuRh mass loading of 10%. The obtained catalyst is named 10-CuRh(Ce) / Al2O3.

[0144] Embodiment 21

[0145] Figure 5-Figure 7A schematic diagram of a high-speed aircraft heat-to-work conversion system according to an embodiment of the present invention is shown. The high-speed aircraft heat-to-work conversion system comprises: a distributed liquid cooling plate 1, a first solenoid valve 2, a heat-to-work conversion plate 3, a gas-liquid storage tank 4, a second solenoid valve 5, a thrust engine 6, a third solenoid valve 7, an oxygen supply system 8, and a fourth solenoid valve 9; the heat-to-work conversion plate 3 is a flat plate structure, loaded with a catalyst as described above; the distributed liquid cooling plate 1 is connected to the inlet of the heat-to-work conversion plate 3 through the first solenoid valve 2, the outlet of the heat-to-work conversion plate 3 is connected to the inlet of the gas-to-liquid storage tank 4, the first outlet of the gas-to-liquid storage tank 4 is connected to the inlet of the thrust engine 6 through the second solenoid valve 5, respectively, the second outlet of the gas-to-liquid storage tank 4 is connected to the inlet of the distributed liquid cooling plate 1 through the third solenoid valve 7, and the inlet of the oxygen supply system 8 is connected to the inlet of the thrust engine 6 through the fourth solenoid valve 9.

[0146] The method for using the high-speed aircraft heat-to-work conversion system of the present embodiment includes: the liquid cooling medium in the distributed liquid cooling plate 1 is heated and vaporized by aerodynamic heat or heat dissipated by the carrier, and then enters the heat-to-work conversion plate 3 through the first solenoid valve 2. Under the action of high-temperature aerodynamic heat and a catalyst, the vaporized liquid cooling medium undergoes a chemical endothermic reaction and produces high-pressure gas small molecules. The high-pressure gas small molecules and the unreacted liquid cooling medium enter the gas-liquid storage tank 4 through a pipeline. The high-pressure gas small molecules can be discharged through the first outlet of the gas-liquid storage tank 4 through the second solenoid valve 5 and the thrust engine 6, and then work to generate thrust. The oxygen supplementation module 8 mixes the oxidizing atmosphere and the discharged high-pressure gas small molecules through the fourth solenoid valve 9 to achieve dual-component work and improve the system thrust. The unreacted liquid cooling medium can be passed through the second outlet of the gas-liquid storage tank 4 through the third solenoid valve 7 into the distributed liquid cooling plate 1 for recycling.

[0147] Embodiment 22

[0148] The ethanol / water mixed solution is used as the heat absorbing medium, the molar ratio of ethanol to water is 1:1.5 (the mass fraction of ethanol is 63%), the initial temperature of the solution is 25°C, the flow rate is 30g / min, and the catalysts prepared in Examples 5-20 and Comparative Examples 1-4 are used as reforming catalysts to test the heat absorbing performance of the system. The heat absorbing system is slightly simplified on the basis of Example 21: the system includes 1 distributed liquid cooling plate and 1 heat-work conversion plate, and a liquid flow pump is added between the two. The flow pump can control the flow rate of the working medium delivered from the liquid cooling plate to the heat-work conversion plate, and the infrared heating furnace is used to simulate thermal heating. The heat-work conversion plate uses 10g of catalyst, and the reaction temperature is controlled by modulating the current and heating power of the heating furnace, which are set to 200°C, 300°C, 500°C, 600°C and 800°C respectively. The reaction pressure is set to 1.0MPa, and the results are shown in Table 1.

[0149] Embodiment 23

[0150] A methanol / water mixed solution was used as the endothermic working fluid, the molar ratio of methanol to water was 1:0.5, the initial temperature of the solution was 25°C, the flow rate was 30 g / min, 10-CuRhPd(Ce) / Ni-P was used as the reforming catalyst, the catalyst mass was 10 g, and the endothermic heat of the endothermic working fluid was measured using the same method as in Example 21. The reaction temperatures were set to 200°C, 300°C, 500°C, 600°C and 800°C, respectively, and the reaction pressure was set to 1.0 MPa. The results are shown in Table 1.

[0151] Embodiment 24

[0152] The isopropanol / water mixed solution was used as the endothermic working fluid, the molar ratio of isopropanol to water was 1:3, the initial temperature of the solution was 25°C, the flow rate was 30 g / min, 10-CuRhPd(Ce) / Ni-P was used as the reforming catalyst, the catalyst mass was 10 g, and the endothermic heat of the endothermic working fluid was measured using the same method as in Example 21. The reaction temperatures were set to 200°C, 300°C, 500°C, 600°C and 800°C, respectively, and the reaction pressure was set to 1.0 MPa. The results are shown in Table 1.

[0153] Embodiment 25

[0154] The endothermic working fluid is a mixed solution of water / ethanol / isopropanol / methanol, and the corresponding mass fractions are 30%, 40%, 20% and 10%, respectively. The initial temperature of the solution is 25°C, the flow rate is 30g / min, the catalyst is 10-CuRhPd(Ce) / Ni-P, and the catalyst mass is 10g. The endothermic heat of the endothermic working fluid is measured by the same method as in Example 21. The reaction temperatures are set to 200°C, 300°C, 500°C, 600°C and 800°C, respectively, and the reaction pressure is set to 1.0MPa. The results are shown in Table 1.

[0155] Table 1 Comparison of heat absorption performance of alcohol and water catalyzed by different catalysts

[0156]

[0157]

[0158] According to the results in Table 1, changes in the catalyst will significantly affect the heat sink of the working fluid, that is, the amount of heat absorbed by the heat-to-work conversion system is closely related to the type of catalyst.

[0159] According to Examples 5 to 11 and Comparative Examples 2 and 3, when the same carrier (nickel foam) and ethanol-water working fluid are used, the CuRh bimetallic catalyst has better endothermic performance than other bimetallic catalysts or single metal Cu catalysts, indicating that there is a good synergistic effect between Cu and Rh metals, and they can efficiently catalyze the alcohol-water reaction to generate synthesis gas (Equation 1). In addition, the performance of the CuPd bimetallic catalyst is second only to the CuRh catalyst, which means that there is also a good synergistic effect between Cu and Pd metals.

[0160] According to Examples 11-14 and Comparative Examples 1-3, the addition of additives is used to enhance the stability of the metal on the foam carrier and adjust the reaction activity; further according to Examples 11-15 and Comparative Example 2, when a small amount of additives is added to the CuRh catalyst, the heat absorption performance of the system can be improved to a certain extent, especially Ce and Zr additives have the best effect compared to La and Mg.

[0161] According to Examples 14-16 and Comparative Example 4, when the foam carrier is changed, the activity order is found to be foam copper > foam nickel > foam titanium, indicating that the thermal conductivity of the metal will significantly affect its activity; and when the catalyst carrier is replaced with ordinary alumina, the heat absorption performance of the system decreases significantly, especially at lower reaction temperatures (300°C and 500°C), the heat absorption performance decreases by nearly 20%, which indicates that when the catalyst heat transfer is poor, it will significantly affect the reaction activity, thereby reducing the heat absorption effect of the system.

[0162] According to Examples 17-20, it can be seen that changing the calcination conditions, such as oxidation calcination, reduction calcination temperature and heating rate, will affect the catalyst reaction conditions. In comparison, high-temperature oxidation calcination (600°C) will significantly reduce the catalyst activity, and increasing the reduction temperature to 600°C will slightly reduce the catalyst performance; the heating rate is changed from rapid calcination (heating to 400-500°C within 10s) to reducing the heating rate (2°C / min) will reduce the catalyst reaction performance.

[0163] According to Example 17 and Examples 23-25, the methanol / water mixed solution exhibits better heat absorption performance in the low temperature zone (<500°C), the ethanol / water solution exhibits better heat absorption performance in the medium temperature zone (500-600°C), and the isopropanol water has better performance in the high temperature zone (>600°C); when the alcohol-water component is adjusted to a water / ethanol / isopropanol / methanol mixed solution, excellent heat sinking is exhibited in a wide temperature range of 300-800°C, indicating that when the multi-component alcohol-water is matched with the foam metal catalyst, the heat-to-work conversion system exhibits more excellent performance.

[0164] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A high thermal conductivity foam metal supported catalyst, characterized in that: The supported catalyst comprises a foam metal carrier and an active metal component and an additive supported on the foam metal carrier; The foam metal carrier comprises one of foam nickel, foam copper and foam titanium; The active metal components include at least two of Cu, Fe, Ni, Mo, Mn, Rh, Pt, and Pd; The auxiliary agent includes one or more of La, Mg, Zr and Ce.

2. The high thermal conductivity foam metal supported catalyst according to claim 1, characterized in that The active metal component is a combination containing at least Cu and at least one of Fe, Ni, Mo, Mn, Rh, Pt and Pd; based on the total molar content of the total active metal ions, the molar content of each metal element in the active metal component accounts for no less than 20% of the total molar content of the metal; The auxiliary agent includes Zr and / or Ce.

3. The high thermal conductivity foam metal supported catalyst according to claim 2, characterized in that: The active metal component is a combination of at least Cu and Rh and at least one of Fe, Ni, Mo, Mn, Pt and Pd; Based on the total molar content of total active metal ions, the molar content of each metal element in the active metal component accounts for no less than 25% of the total molar content of the metal.

4. The high thermal conductivity foam metal supported catalyst according to claim 1, characterized in that: In the supported catalyst, the mass of the active metal component is 1% to 20% of the total mass of the supported catalyst, and the mass of the auxiliary agent is 1% to 10% of the total mass of the supported catalyst; The pore size of the foam metal carrier is 0.1 mm to 1.2 mm; the porosity of the foam metal carrier is 40% to 90%.

5. A method for preparing a highly thermally conductive foamed metal supported catalyst as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: (1) dissolving an active metal component precursor and an auxiliary agent precursor in water, adding a complexing agent and mixing them to obtain an impregnation solution; (2) adding a foamed metal carrier to the impregnation solution for impregnation, then taking it out and drying it, and then quickly placing the precursor obtained after drying into a tubular furnace preheated to 400° C. to 600° C., and rapidly heating the precursor to a set temperature within 0 s to 10 s in an oxidizing atmosphere and / or a reducing atmosphere, keeping the temperature for 10 min to 120 min, cooling it to room temperature and then taking it out of the furnace to obtain the high thermal conductivity foamed metal supported catalyst.

6. The preparation method according to claim 5, characterized in that: In step (1), the active metal component precursor is a soluble salt or acid of the active metal component; the auxiliary agent precursor is a soluble salt or acid of the auxiliary agent; the complexing agent includes one or more of glycine, glycerol, citric acid and ethylene glycol; the ratio of the total amount of metal ions in the impregnation solution to the amount of the complex is 1:(1-6); the mixing temperature is 60°C-80°C; In step (2), the immersion time is 10 min to 30 min; the drying temperature is 80° C. to 120° C.; the immersion is performed multiple times, and the number of times of the multiple immersion is 1 to 5 times; The multiple impregnation method includes: drying and calcining the product after each impregnation before the next impregnation.

7. A use of a highly thermally conductive foamed metal supported catalyst as claimed in any one of claims 1 to 4, or a highly thermally conductive foamed metal supported catalyst prepared by the preparation method as claimed in any one of claims 5 to 6 in catalyzing alcohol-water reforming reaction to produce synthesis gas, characterized in that: The application is used in high-speed aircraft heat-to-work conversion systems.

8. The use according to claim 7, characterized in that: The alcohol aqueous solution includes an aqueous solution containing at least one of methanol, ethanol, ethylene glycol, isopropanol and n-propanol; The temperature of the alcohol-water reforming reaction is 200°C to 800°C The reaction pressure of the alcohol-water reforming reaction is 5 bar to 20 bar.

9. The use according to claim 8, characterized in that: The alcohol aqueous solution includes an aqueous solution containing at least two of methanol, ethanol, ethylene glycol and isopropanol; the mass content of a single alcohol component in the alcohol aqueous solution is ≥10%, and the total mass fraction of alcohol in the alcohol aqueous solution is 40% to 70%; The temperature of the alcohol-water reforming reaction is 300°C to 600°C The reaction pressure of the alcohol-water reforming reaction is 5 bar to 10 bar.

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