Highly heat-conductive foam metal supported catalyst, preparation method and application thereof

Abstract

The application discloses a high-thermal-conductivity foam metal supported catalyst and a preparation method and application thereof. The supported catalyst comprises a foam metal carrier and active metal components 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 comprise at least two of Cu, Fe, Ni, Mo, Mn, Rh, Pt and Pd. The additive comprises one or more than two of La, Mg, Zr and Ce. The high-thermal-conductivity foam metal supported catalyst can be used in a high-speed aircraft thermal power conversion reactor. Through the construction of strengthened heat conduction and high-efficiency active centers, the endothermic chemical reforming reaction of a multi-component alcohol and water system is quickly catalyzed, then the "harmful" aerodynamic heat is absorbed, and high-temperature and high-pressure small molecule gases (hydrogen, carbon monoxide and the like) are generated to produce thrust for work, so that the aerodynamic heat management and thermal power conversion of the high-speed aircraft are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalysis, more particularly, to a high-thermal-conductivity foam metal supported catalyst and a preparation method and application thereof. BACKGROUND

[0002] High-speed aircraft has become the key of international strategic game because of its rapid response, quick strike and easy penetration. When high-speed aircraft flies at high speed, the temperature of its outer wall and nearby area will rapidly increase due to the effects of shock wave compression and viscous friction. In order to ensure the normal operation of the internal components within the allowable temperature range and maintain the aerodynamic shape, effective structure 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 heat insulation or ablative materials for phase change heat absorption is the most widely used aerodynamic heat treatment measure. Such thermal protection technology has relatively simple structure, but the preparation process is complex and the cost is high. Ablative heat protection system will gradually ablate with the increase of temperature during high-speed flight, which is easy to change the overall aerodynamic shape and cause accidents. At the same time, due to the weak heat absorption capacity of passive thermal protection system, the required material thickness and weight are large in long-time flight application, which seriously compresses the effective payload of the aircraft.

[0003] Compared with passive thermal protection, active thermal protection has the advantages of strong cooling capacity, long-time heating under high-density heat flow and closed-loop temperature control by using cooling working medium and various cooling forms to take away or block heat from the structure. Active thermal protection technology is mainly divided into two categories, namely, sweating cooling and convection cooling. The commonly used cooling working medium of sweating cooling is water, which uses the way of biological sweating to absorb heat and form a heat shield by using the latent heat of water vaporization, but the system reliability is poor. Convection cooling is commonly used in space and air vehicles, which generally uses circulating liquid hydrocarbon fuel as coolant to take away the heat of the structure surface by using the physical heat capacity of the fuel. Due to the limitation of fuel coking, this heat absorption mode is only suitable for supersonic flight at a speed lower than 5 Mach.

[0004] In recent years, with the further improvement of the performance of high-speed aircraft, especially the development of long-time high-speed aircraft, the aerodynamic heat environment of high-speed aircraft becomes more complex and severe. Therefore, it is of great significance to develop an efficient and reliable method for absorbing the aerodynamic heat of high-speed aircraft.

[0005] In light of these challenges, experimental and theoretical research has revealed that using an alcohol-water mixture as the cooling fluid for an active thermal protection system can absorb significant amounts of aerodynamic heat through a physical vaporization reaction. Specifically, when a suitable catalyst is present in the system, the alcohol and water can undergo a highly endothermic reforming reaction. For example, the reforming reaction of an ethanol-water solution upon vaporization produces hydrogen and carbon monoxide (Equation 1), tripling the gas volume and absorbing 256.8 kJ of heat per mole of fluid. When the aerodynamic heat temperature reaches 600°C, pure water absorbs only 3.6 MJ / kg, while the total physical and chemical heat absorbed by an ethanol-water mixture under the same conditions can reach over 6.2 MJ / kg. Furthermore, the generated small molecule gases (such as hydrogen and carbon monoxide) can be used to perform external work. Therefore, using this green working fluid not only improves the system's heat absorption capacity but also converts aerodynamic heat into chemical energy, realizing waste heat utilization. This can reduce the thickness of the aircraft's thermal insulation, increase the system's payload, and enhance aircraft maneuverability.

[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-gas shift reaction (Equation 4; exothermic). As a result, the chemical reaction not only has a lower heat absorption capacity than ethanol reforming to produce synthesis gas (Equation 1) and methanol decomposition reaction (Equation 5), but also has a decreased gas volume expansion effect, resulting in a decrease in the system's work capacity. In addition, the traditional reforming hydrogen production reaction (a reaction that increases volume) is generally carried out at atmospheric pressure to increase the reaction rate and promote hydrogen generation. However, for heat-to-work conversion systems, to improve the work efficiency, the chemical reaction must be carried out under high-pressure conditions (the higher the pressure, the greater the ability to do external work). However, in the reforming reaction products, H2 / CO or H2 / CO2 coexist in large quantities, and under high-pressure conditions, a methanation reaction with volume reduction and strong heat release is prone to occur (Equations 6 and 7), thereby reducing the system's heat absorption and work efficiency.

[0007] In addition to differences in reaction conditions, the requirements for catalysts also vary significantly when the type of alcohol is changed. For example, for methanol steam reforming (Nature Catalysis, 2022, 5, 99), the main active components of the industrially applied catalyst are Cu / Zn / Al, and the operating temperature is mainly between 180-300°C. In contrast, for ethanol-water reforming catalysts, literature research has mainly focused on Ni-based catalysts (Renewable and Sustainable Energy Reviews, 2023, 175, 113-184), and due to the high stability of the CC bond, the reaction temperature is generally between 350-600°C. For heat-to-power conversion systems, to broaden the effective operating temperature range, the required alcohol-water working fluid is often a multi-component composite system. For example, low-carbon alcohol-water reforming in the working fluid can promote the absorption of low-temperature aerodynamic heat, while high-carbon alcohol-water reforming can increase the total heat absorption capacity of the endothermic working fluid. Therefore, traditional catalysts specifically designed 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 nature of the alcohol-water reaction, catalysts based on traditional supports (such as alumina) can form localized cold spots during the reaction, leading to a rapid decrease in reaction rate. This is because the aerodynamic heat is transferred slowly from the surface of the reactor (made of metal) to the interior, thus limiting the rapid absorption of aerodynamic heat. Therefore, enhancing heat transfer in the catalytic bed is 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 the heat-to-work conversion reactor of high-speed aircraft. By enhancing heat conduction and constructing efficient active centers, it can rapidly catalyze the endothermic chemical reforming reaction of the 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, 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; and the additive comprises one or more of La, Mg, Zr and 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 auxiliary agent 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 not 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 to obtain an impregnation solution;

[0022] (2) adding the foam metal support into 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 0s to 10s under an oxidizing atmosphere and / or a reducing atmosphere, keeping the temperature for 10min to 120min, and then cooling it to room temperature and taking it out of the furnace to obtain the high thermal conductivity foam 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 step (2), the impregnation time is 10 min to 30 min; the drying temperature is 80°C to 120°C; the roasting temperature is 400°C to 600°C, preferably the roasting temperature is 400 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 performing 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 thermal power conversion system includes: a distributed liquid cooling plate 1, a first solenoid valve 2, a thermal power 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 thermal power conversion plate 3 is a flat plate structure, loaded with the loaded high-entropy metal catalyst as described above, or the 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 thermal power conversion plate 3 through the first solenoid valve 2, the outlet of the thermal power 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 respectively 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 supply 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 supplementation system 8 mixes the oxidizing atmosphere and the discharged high-pressure gas small molecules through the fourth solenoid valve 9 to achieve two-component work and increase 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 thermal-to-power conversion system includes: a distributed liquid cooling plate and a thermal-to-power conversion plate. The distributed liquid cooling plate is connected to the thermal-to-power conversion plate through a liquid flow pump. The thermal-to-power 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 thermal-to-power conversion plate, and thermal heating is simulated by an infrared heating furnace.

[0032] The implementation 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 metal catalysts supported on traditional carriers (such as metal oxides such as aluminum oxide and silicon oxide), the catalyst of the present invention can quickly transfer 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 achieve 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 calcinations can effectively increase the active metal loading, strengthen the interaction between the active metal and the foam carrier, and improve the stability of the catalyst.

[0036] The supported catalyst of the present invention can meet the requirements of a 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 traditional passive insulation methods, the heat-to-work conversion system based on the catalyst of the present invention is an active thermal protection technology, which has the advantages of strong cooling capacity, ability to withstand long-term heating with high-density heat flow, and realization of 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 of water sweating (~3MJ / kg), effectively enhancing the heat absorption performance of the system and generating 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 isopropyl alcohol 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 at 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 according to embodiment 21 of the present invention.

[0044] Figure 6 This is a schematic diagram of the heat-to-work conversion plate structure 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 will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

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

[0049] Working fluid heat sink test method:

[0050] The heat sink of the working fluid is evaluated by the current heating reaction, and the heat sink of the endothermic process is calculated using the energy conservation method.

[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 medium (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 using thermodynamic calculations, where the initial temperature of methanol was room temperature (25°C). The heat absorbed by the complete decomposition of methanol into H2 and CO (Equation 2) at different temperatures is as follows: Figure 1 shown.

[0056] Example 2

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

[0058] Example 3

[0059] Calculate 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). The heat absorbed by the solution at different temperatures for complete decomposition into H2 and CO (Equation 4) is 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 Figures 1-4 It can be seen that the methanol decomposition reaction is relatively active. At around 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 around 250°C and 300°C, respectively. In addition, for the three alcohols, the 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 values, it can be seen that the maximum heat sink value increases significantly with the increase in the number of carbon atoms. 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. This shows that in order to make the endothermic working fluid exhibit 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 heat absorption capacity of the 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 were used as metal precursors in a molar ratio of 1:1. They were dissolved in deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. In addition, zirconium nitrate was added to the solution with a molar ratio of Zr to Cu of 1:1. Then, glycine was added to the solution to obtain a metal ion precursor solution in which the molar ratio of glycine to total metal ions was 1:1, that is, the concentration of glycine in the solution was 0.15 mol / L. The beaker containing the above solution was placed in a 60°C water bath and slowly evaporated until the solution became viscous. The foamed Ni support was then immersed in the above viscous solution and removed after stabilization for 10 minutes. It was then swept with compressed air for 2 minutes, then rapidly heated to 450°C in air for 10 minutes, and then rapidly reduced at 400°C for 30 minutes using hydrogen. Heating was stopped and the solution was naturally cooled to room temperature. The impregnation, air purge, and calcination steps were repeated four times until the active metal loaded on the metal foam 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 embodiment 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 embodiment 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 embodiment 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 embodiment 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 embodiment was obtained according to the preparation method of Example 5.

[0087] Example 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 embodiment 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 embodiment was obtained according to the preparation method of Example 11.

[0095] Example 13

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

[0097] The difference between this example and Example 11 is that the assistant precursor is magnesium nitrate, and the molar ratio of Mg and 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] Example 14

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

[0101] The difference between this example and Example 11 is that the assistant precursor is cerium nitrate, and the molar ratio of Ce and 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] Example 15

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

[0105] The difference between this example and Example 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 foamed titanium:

[0109] The difference between this example and Example 14 is that the foamed nickel carrier is replaced by a foamed titanium carrier.

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

[0111] Example 17

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

[0113] The difference between this example and Example 14 is that the metal precursors are copper nitrate, rhodium chloride, and palladium chloride, and 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 promoter precursor was cerium nitrate, the molar ratio of Ce to Cu was 1.5:1 and the molar ratio of Ce to total amount of active metals was 1:2, which was the same as Example 14.

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

[0116] Example 18

[0117] The CuRhPd(Ce)-HR metal catalyst supported on the nickel foam was prepared as follows:

[0118] This example differs from Example 17 only in that the reduction temperature was 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] Example 19

[0121] The CuRhPd(Ce)-HO metal catalyst supported on the nickel foam was prepared as follows:

[0122] This example differs from Example 17 only in that the oxidation temperature was 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] Example 20

[0125] The CuRhPd(Ce)-C metal catalyst supported on the nickel foam was prepared as follows:

[0126] This example differs from Example 17 only in that the heating rate of the oxidation and reduction roasting steps was 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] The Cu metal catalyst (10-Cu(Ce) / Ni-P) supported on the nickel foam was prepared as follows:

[0130] This comparative example differs from Example 15 only in that the metal precursor was 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] A Cu metal catalyst supported on nickel foam (10-CuRh / Ni-P) was prepared as follows:

[0134] This comparative example differs from Example 15 only in that no cerium nitrate was added.

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

[0136] Comparative Example 3

[0137] A Cu metal catalyst supported on nickel foam (10-Cu / Ni-P) was prepared as follows:

[0138] This comparative example differs from Example 15 only in that the metal precursors were only copper nitrate and no cerium nitrate was added.

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

[0140] Comparative Example 4

[0141] A CuRh(Ce) metal catalyst supported on alumina was prepared as follows:

[0142] This comparative example differs from Example 15 only in that the support was an alumina support.

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

[0144] Example 21

[0145] Figure 5-Figure 7A schematic diagram of a high-speed aircraft heat-to-power conversion system according to an embodiment of the present invention is shown. The high-speed aircraft heat-to-power conversion system includes: a distributed liquid cooling plate 1, a first solenoid valve 2, a heat-to-power 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-power conversion plate 3 is a flat plate structure and is loaded with the catalyst described above; the distributed liquid cooling plate 1 is connected to the inlet of the heat-to-power conversion plate 3 through the first solenoid valve 2, the outlet of the heat-to-power conversion plate 3 is connected to the inlet of the gas-to-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 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 this embodiment includes: after the liquid cooling medium in the distributed liquid cooling plate 1 is heated and vaporized by aerodynamic heat or heat dissipated by the carrier, it 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 to produce 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, thereby performing work to generate thrust. The oxygen supply system 8 mixes the oxidizing atmosphere and the discharged high-pressure gas small molecules through the fourth solenoid valve 9 to achieve two-component work and increase 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] Example 22

[0148] The system's heat absorption performance was tested using an ethanol / water mixture as the endothermic working fluid, with a molar ratio of 1:1.5 (ethanol mass fraction of 63%), an initial solution temperature of 25°C, and a flow rate of 30 g / min. The catalysts prepared in Examples 5-20 and Comparative Examples 1-4 were used as reforming catalysts. The endothermic system was slightly simplified from that in Example 21: it comprised one distributed liquid cooling plate and one heat-to-power conversion plate, with a liquid flow pump added between them to control the flow rate of the working fluid from the liquid cooling plate to the heat-to-power conversion plate. Thermal heating was simulated using an infrared heating furnace. The heat-to-power conversion plate used 10 g of catalyst. The reaction temperatures were controlled by modulating the furnace's current and heating power, set to 200°C, 300°C, 500°C, 600°C, and 800°C, respectively. The reaction pressure was set to 1.0 MPa. The results are shown in Table 1.

[0149] Example 23

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

[0151] Example 24

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

[0153] Example 25

[0154] The endothermic working fluid is a mixed solution of water / ethanol / isopropanol / methanol, with corresponding mass fractions of 30%, 40%, 20% and 10%, respectively. The initial temperature of the solution is 25°C, the flow rate is 30 g / min, the catalyst is 10-CuRhPd(Ce) / Ni-P, and the catalyst mass is 10 g. The heat absorption of the endothermic working fluid is measured using 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 1.0 MPa. The results are shown in Table 1.

[0155] Table 1 Comparison of heat absorption performance of alcohol-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 medium, that is, the heat absorption of the heat-to-work conversion system is closely related to the type of catalyst.

[0159] According to the embodiments 5-11 and the comparative examples 2 and 3, when using the same carrier (foamed nickel) and the ethanol water working fluid, the CuRh bimetallic catalyst has better heat absorption performance than other bimetallic catalysts or the single metal Cu catalyst, which shows that there is a better synergistic effect between Cu and Rh, and the CuRh catalyst can efficiently catalyze the alcohol water reaction to generate synthesis gas (equation 1). In addition, the performance of the CuPd bimetallic catalyst is only slightly lower than that of the CuRh catalyst, which means that there is also a better synergistic effect between Cu and Pd.

[0160] According to the embodiments 11-14 and the comparative examples 1-3, the addition of the auxiliary agent is used to strengthen the stability of the metal on the foamed carrier and to adjust the reaction activity. According to the embodiments 11-15 and the comparative example 2, when a small amount of auxiliary agent is added to the CuRh catalyst, the heat absorption performance of the system can be improved to a certain extent, and the effect of Ce and Zr auxiliary agents is the best compared with La and Mg auxiliary agents.

[0161] According to the embodiments 14-16 and the comparative example 4, when the foamed carrier is changed, it is found that the activity order is foamed copper > foamed nickel > foamed titanium, which shows that the heat conduction performance of the metal can significantly affect the activity. When the catalyst carrier is replaced by ordinary alumina, the heat absorption performance of the system is significantly reduced, especially at a lower reaction temperature (300℃ and 500℃), the heat absorption performance is reduced by nearly 20%, which shows that when the heat transfer of the catalyst is poor, the reaction activity will be significantly affected, and then the heat absorption effect of the system will be affected.

[0162] According to the embodiments 17-20, when the calcination conditions are changed, such as oxidation calcination, reduction calcination temperature and heating rate, the reaction conditions of the catalyst will be affected. Compared with the high-temperature oxidation calcination (600℃), the catalyst activity is obviously reduced. When the reduction temperature is increased to 600℃, the catalyst performance is slightly reduced. When the heating rate is reduced (2℃ / min), the reaction performance of the catalyst is reduced.

[0163] According to the embodiments 17 and 23-25, the methanol / water mixed solution shows better heat absorption performance in the low temperature zone (<500℃), the ethanol / water solution shows better heat absorption performance in the medium temperature zone (500-600℃), and the isopropanol / water solution shows better performance in the high temperature zone (>600℃). When the alcohol / water components are adjusted to water / ethanol / isopropanol / methanol mixed solution, the system shows excellent heat sink in the wide temperature zone of 300-800℃, which shows that the multi-component alcohol / water and the foamed metal catalyst show better performance when they are combined.

[0164] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A high thermal conductivity foam metal supported catalyst, characterized in that: The supported catalyst comprises a foam metal support and an active metal component and an additive supported on the foam metal support; The foam metal carrier comprises one of foam nickel, foam copper and foam titanium; 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 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 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; 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 containing 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 high thermal conductivity foam metal supported catalyst according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) After dissolving the active metal component precursor and the auxiliary agent precursor in water, a complexing agent is added and mixed to obtain an impregnation solution; (2) Adding the foam metal support into 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~600°C, and rapidly heating the precursor to the set temperature within 0s~10s under an oxidizing atmosphere and / or a reducing atmosphere, keeping the temperature for 10min~120min, cooling it to room temperature and then taking it out of the furnace to obtain the high thermal conductivity foam 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 to 80°C; In step (2), the dipping time is 10 min to 30 min; the drying temperature is 80° C. to 120° C.; the dipping is performed multiple times, and the number of times of the multiple dipping is 1 to 5 times; The multiple impregnation method includes: drying and calcining the product after each impregnation before performing the next impregnation.

7. A use of the high thermal conductivity foam metal supported catalyst according to any one of claims 1 to 4, or the high thermal conductivity foam metal supported catalyst prepared by the preparation method according to 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 a high-speed aircraft heat-to-power conversion system.

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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