Molding method of catalyst for catalyzing liquid organic hydrogen carrier to absorb and desorb hydrogen in fixed bed reactor
By optimizing the catalyst forming method and combining the treatment of rare earth metal hydrides with precious or non-precious metal salts, the problem of the difficulty in forming rare earth hydride catalysts in fixed-bed reactors was solved, and efficient addition and dehydrogenation performance was achieved.
Patent Information
- Application Number
- CN202511114923.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-11
- Publication Date
- 2025-11-21
AI Technical Summary
Existing catalysts perform poorly in the addition and dehydrogenation of liquid organic hydrogen supports in fixed-bed reactors, and it is difficult to maintain efficient and stable catalytic performance, especially rare earth hydride catalysts which are difficult to form.
The catalyst is prepared by dissolving a binder in a solvent, refrigerating it, mixing it with rare earth metal hydrides and liquid organic hydrogen carriers, and then performing vacuum stirring, molding and granulation, high-temperature sintering, impregnation with precious metal or non-precious metal salt solutions, vacuum drying and reduction treatment.
It significantly improves the hydrogenation and dehydrogenation effect of liquid organic hydrogen carriers in fixed-bed reactors. The catalyst exhibits excellent hydrogenation and dehydrogenation activity, with a conversion rate of over 99%.
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Figure CN120984290A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of catalyst and hydrogen storage technology, and particularly relates to a catalyst forming method for catalyzing liquid organic hydrogen carrier to absorb and release hydrogen in a fixed bed reactor. BACKGROUND
[0002] Energy crisis is a major challenge faced by human society in the 21st century, so it is urgent to widely use renewable energy to replace traditional fossil fuels. Hydrogen has been considered as an ideal solution to energy problems for its clean and pollution-free characteristics. However, due to the lack of efficient hydrogen storage technology, the storage and transportation of hydrogen have become a key bottleneck restricting its large-scale application. Under this background, liquid organic hydrogen carrier (LOHCs) as an innovative hydrogen storage method has attracted widespread attention from academia and industry due to its high hydrogen storage capacity, good safety and thermal stability, and good compatibility with existing fuel facilities. Among them, N-ethylcarbazole (NEC) has become one of the most potential LOHC candidate materials due to its excellent hydrogen storage performance (hydrogen storage mass fraction can reach about 5.8%, and the converted volume hydrogen storage density is about 54 grams of hydrogen per liter), suitable operating temperature (lower than 473K), and lower volatility and toxicity. Although NEC shows great advantages in hydrogen storage, there is a problem of slow kinetics in the process of hydrogen absorption and release. Therefore, catalysts are needed to improve the hydrogenation and dehydrogenation performance of NEC as LOHC.
[0003] Previous studies have shown that ruthenium (Ru)-based catalysts exhibit the best performance in the hydrogenation of N-ethylcarbazole (NEC), while palladium (Pd)-based catalysts show the best performance in the dehydrogenation of dodecahydro-N-ethylcarbazole (12H-NEC). However, when these catalysts are applied in fixed-bed reactors for hydrogenation and dehydrogenation performance tests, their actual performance does not meet expectations. The reason may be that fixed-bed reactors require catalysts to be packed in granular form, which means that the catalysts need to be shaped. Although our previous studies have explored various binders for catalyst shaping, such as sodium carboxymethylcellulose and polyvinylpyrrolidone (PVP), related patent application numbers: 2024224972061, 2024114267666, although these catalysts show good catalytic activity in reaction kettle tests, the catalytic efficiency of these shaped catalysts is not fully demonstrated when applied in fixed beds. This difference is mainly due to the fundamental difference between fixed-bed reaction mode and reaction kettle reaction mode. In a reaction kettle, the amount of reactant and catalyst is fixed, and as the hydrogenation or dehydrogenation reaction proceeds, the reactant concentration gradually decreases, resulting in a higher reaction rate at the beginning and then gradually slowing down. In contrast, a fixed-bed reactor uses a continuous flow mode, i.e., the catalyst remains fixed, while the LOHC continuously passes through the catalyst bed for reaction. This requires the catalyst not only to have high activity but also to maintain stable performance for a long time to ensure that the hydrogenation or dehydrogenation rate remains at a high level throughout the reaction process. Therefore, in order to improve the performance of the catalyst in the fixed-bed reactor, we also need to further optimize the shaping method and chemical composition of the catalyst.
[0004] Before this, we have verified that rare earth hydride can effectively promote the catalytic hydrogenation and dehydrogenation of NEC by providing a new hydrogen transfer path. In particular, the developed Pd / Al2O3-YH3 catalyst for the reversible hydrogen storage of NEC, whether hydrogenation or dehydrogenation, has the highest turnover frequency (TOF). The Pd / Al2O3-YH3 catalyst can achieve a reversible hydrogen storage capacity of more than 5.5 wt% and 3 stable cycles (International Journal of Hydrogen Energy 45 (2020) 33657-33662).
[0005] Unfortunately, however, rare earth hydrides are highly active and easily react with conventional solvents such as water, making them difficult to shape. SUMMARY First, the technical problems to be solved by the present invention are:
[0006] The present invention aims to provide a shaping method for a rare earth metal hydride-doped catalyst that can significantly improve the dehydrogenation effect of liquid organic hydrogen carriers in a fixed-bed reactor. II. The technical scheme of the present application is as follows:
[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a catalyst forming method for catalyzing liquid organic hydrogen carrier to absorb and release hydrogen in a fixed bed reactor, the forming method comprising the following steps: 1) dissolving a binder in a proper amount of solvent ethanol or acetone to prepare a binder solution, and refrigerating the binder solution; 2) pouring the refrigerated binder solution, rare earth metal hydride and liquid organic hydrogen carrier into a sealed container to prepare a mixture under stirring and vacuumizing at room temperature; taking out the mixture after it becomes viscous to form and granulate; 3) placing the carrier material mixed with rare earth metal hydride after forming and granulating into an atmosphere furnace to perform high-temperature sintering at 600-800℃; 4) immersing the carrier material after high-temperature sintering in a Pd, Ru or Ni salt solution, and performing vacuum stirring and drying at room temperature, wherein the solvent of the Pd, Ru or Ni salt solution is a volatile solvent selected from one of ethanol, acetone or tetrahydrofuran; 5) reducing the dried carrier material under H2 or Ar / H2 at 300-600℃ to prepare a catalyst.
[0008] Preferably, the refrigeration condition of the refrigeration in step 1) of the present application is that the refrigeration temperature is 4-10℃, and the refrigeration time is 0.5-1h.
[0009] Preferably, the binder in step 1) of the present application is sodium carboxymethyl cellulose or polyvinylpyrrolidone.
[0010] Preferably, the rare earth metal hydride in step 2) of the present application is one or both of YH2 or YH3.
[0011] Preferably, the liquid organic hydrogen carrier in step 2) of the present application is Al2O3 or TiO2.
[0012] Preferably, the volume ratio of the solvent ethanol or acetone to the rare earth metal hydride is (0.685-21.5):1; the mass ratio of the binder to the liquid organic hydrogen carrier is (1.1-4):20; and the mass ratio of the rare earth metal hydride to the liquid organic hydrogen carrier material is (1-10):10.
[0013] Preferably, the Ru salt in the present application is selected from one or more of ruthenium acetate, triruthenium dodecacarbonyl or ruthenium acetylacetonate; the Pd salt is selected from one or more of palladium nitrate, palladium acetate or palladium acetylacetonate; and the Ni salt is nickel nitrate.
[0014] Preferably, when the Ni salt solution is selected, the non-noble metal Ni in the prepared catalyst accounts for 5-20% of the total mass of the catalyst; when the Pd, Ru salt solution is selected, the noble metal Pd, Ru in the prepared catalyst accounts for 0.3-3% of the total mass of the catalyst. Third, technical effects and advantages of the present application:
[0015] Compared with the prior art, the present application has the following advantages: 1) The addition of the rare earth metal hydride in the organic liquid plus dehydrogenation catalyst carrier of the present application provides a new hydrogen transfer path, effectively promoting the catalytic hydrogenation and dehydrogenation of NEC.
[0016] 2) The molding method of the rare earth metal hydride for the organic liquid catalyst carrier of the present application solves the problem of high activity and difficult molding of the rare earth metal hydride.
[0017] 3) The organic liquid catalyst of the present application shows excellent hydrogenation and dehydrogenation effect when applied to fixed bed hydrogenation. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 Macroscopic morphology diagram of the catalyst prepared in Example 1.
[0019] Figure 2 XRD diagram of the catalyst prepared in Example 1. DETAILED DESCRIPTION
[0020] The present application will be further described below in combination with examples and comparative examples. Example 1
[0021] Sodium carboxymethyl cellulose 11 g was dissolved in 430 mL of ethanol, and a sodium carboxymethyl cellulose solution was prepared after the sodium carboxymethyl cellulose was completely dissolved. The sodium carboxymethyl cellulose solution was then transferred to a refrigerator and refrigerated at 4°C for 0.5 h to prepare a binder solution. A mixture of 20 g of YH3 and YH2 (mass ratio of YH3 to YH2 was 1:1) and 200 g of liquid organic hydrogen carrier Al2O3 was then dispersed in the binder solution taken out at room temperature. The mixture was dried by vacuumizing and stirring at room temperature in a vacuum sealed container to prepare a mixture. After the mixture was stirred to be viscous, the mixture was placed in a granulator to be shaped and granulated. The shaped granules were then vacuum dried in a sealed container. The shaped carrier granules mixed with rare earth metal hydride were then placed in an atmosphere sintering furnace and sintered at 600°C under Ar / H2 atmosphere for 2 h. The sintered carrier material had a total mass of 225 g. Ruthenium acetate 15.089 g was then dissolved in 403 mL of ethanol at room temperature to prepare a ruthenium acetate ethanol solution, and the shaped carrier material was then poured into the ruthenium acetate ethanol solution and vacuum stirred and dried. Finally, the dried catalyst precursor was placed in an atmosphere furnace and reduced at 300°C under H2 atmosphere. The reduced catalyst was named Y1, and the content of Ru in the Y1 catalyst was about 3%. The macroscopic morphology thereof is shown in Figure 1 , and the XRD pattern thereof is shown in Figure 2 .
[0022] 180 g of Y1 catalyst was placed in a fixed bed hydrogenation reactor, the fixed bed was vacuumized and pressure maintained for a period of time, and then the reaction system was heated to 150°C, and 8 MPa of hydrogen was circulated into the reaction system. Then, a metering pump was used to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time was 1 h. After the reaction was completed, the product was taken for chromatographic characterization. The results showed that in the fixed bed, the conversion rate of N-ethylcarbazole under Y1 catalysis was >99%. Example 2
[0023] Take 20 g of polyvinylpyrrolidone PVP, dissolved in 430 mL of acetone, and wait for the PVP to completely dissolve to prepare a PVP solution; then transfer the PVP solution to a refrigerator and store at 10°C for 1 h. Take 100 g of YH2 and 100 g of liquid organic hydrogen carrier TiO2 and disperse them in the PVP solution taken out at room temperature. Place them in a vacuum sealed container and stir and dry under vacuum at room temperature to prepare a mixture; after the mixture is stirred to be sticky, place the mixture in a granulator to form and granulate. Then dry the formed particles in a sealed container under vacuum. Put the formed carrier particles into an atmosphere sintering furnace and sinter them at 800°C under H2 atmosphere for 2 h. The sintered carrier material has a total mass of 210 g. Take 25.6 g of acetylacetone ruthenium and dissolve it in 430 mL of acetone at room temperature, and then pour the sintered carrier material into the acetone solution of acetylacetone ruthenium and stir and dry under vacuum. Finally, put the dried catalyst precursor into an atmosphere furnace and reduce it at 300°C under Ar / H2 atmosphere. The reduced catalyst is named Y2, and the content of Ru in the Y2 catalyst is about 3%.
[0024] Put 180 g of Y2 catalyst into a fixed-bed hydrogenation reactor, and after the fixed bed is pumped to vacuum and kept for a period of time, heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then use a metering pump to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is 1 h. After the reaction is completed, take the product for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under the catalysis of Y2 catalyst is >99%. Example 3
[0025] Take 23 g of polyvinylpyrrolidone PVP, dissolved in 370 mL of ethanol, and when the PVP is completely dissolved, a PVP solution is prepared; then the PVP solution is transferred to a refrigerator and refrigerated at 4°C for 0.5 h. Then take 54 g of a mixture of YH3 and YH2 (wherein the mass ratio of YH3 to YH2 is 1:1) and 180 g of liquid organic hydrogen carrier Al2O3, and disperse them in the PVP solution taken out at room temperature. Place in a vacuum sealed container and dry by stirring under vacuum at room temperature, to prepare a mixture; after the mixture is stirred to be sticky, the mixture is placed in a granulator for molding and granulation. Then the molded particles are vacuum dried in a sealed container. Then the molded carrier particles are placed in an atmosphere sintering furnace and sintered at 700°C under H2 atmosphere for 2 h, and the sintered carrier material has a total mass of 240 g. Then take 46.953 g of triruthenium dodecacarbonyl, dissolved in 370 mL of tetrahydrofuran at room temperature, and then pour the molded carrier material into the tetrahydrofuran solution of triruthenium dodecacarbonyl and vacuum stir dry. Finally, the dried catalyst precursor is placed in an atmosphere furnace and reduced at 300°C under Ar / H2 atmosphere. The reduced catalyst is named Y3, and the content of Ru in the Y3 catalyst is about 3%.
[0026] Place 180 g of Y3 catalyst in a fixed-bed hydrogenation reactor, and after the fixed bed is pumped to vacuum for a period of time, the reaction system is heated to 150°C, and then 8 MPa of hydrogen is circulated into the reaction system. Then a metering pump is used to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is 1 h. After the reaction is completed, the product is taken for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under Y3 catalysis is >99%. Example 4
[0027] Take 23 g of polyvinylpyrrolidone PVP, dissolved in 370 mL of ethanol, and wait for the PVP to completely dissolve. Then transfer the PVP solution to a refrigerator and store it at 4°C for 0.5 h. Take 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al2O3, and disperse them in the PVP solution at room temperature. Place them in a vacuum sealed container and dry them by stirring under vacuum at room temperature. When the carrier is stirred to be sticky, place the carrier material in a granulator to form and granulate. Then dry the formed particles in a sealed container under vacuum. Then put the formed carrier particles into an atmosphere sintering furnace, and sinter them at 700°C under H2atmosphere for 2 h. The sintered carrier material has a total mass of 240 g. Take 2.286 g of palladium nitrate, and dissolve it in 370 mL of tetrahydrofuran at room temperature. Then pour the formed carrier material into the tetrahydrofuran solution of palladium acetylacetate, and stir and dry it under vacuum. Finally, put the dried catalyst precursor into an atmosphere furnace and reduce it at 300°C under Ar / H2atmosphere. The reduced catalyst is named Y4, and the content of Pd in the Y4 catalyst is about 0.3%.
[0028] Put 180 g of Y4 catalyst into a fixed-bed hydrogenation reactor, and vacuumize the fixed bed for a period of time. Then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min using a metering pump, and the total reaction time is 1 h. After the reaction is completed, take the product and perform chromatographic characterization. The results show that the conversion rate of N-ethylcarbazole in the fixed bed under Y4 catalysis is >99%.
[0029] Put 180 g of Y4 catalyst into a fixed-bed hydrogenation reactor, and vacuumize the fixed bed for a period of time. Then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min using a metering pump, and the total reaction time is 1 h. After the reaction is completed, take the product and perform chromatographic characterization. The results show that the conversion rate of N-ethylcarbazole in the fixed bed under Y4 catalysis is >99%. Example 5
[0030] Take 23 g of polyvinylpyrrolidone PVP, dissolve in 370 mL of ethanol, wait for PVP to completely dissolve, transfer the PVP solution to the refrigerator and refrigerate at 4°C for 0.5 h. Take 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al2O3 and disperse in the PVP solution taken out at room temperature. Place in a vacuum sealed container and dry under vacuum while stirring at room temperature. After the carrier is stirred to be sticky, place the carrier material in a granulator for molding and granulation. Then dry the molded particles in a sealed container under vacuum. Put the molded carrier particles into an atmosphere sintering furnace, sinter at 700°C under H2 atmosphere for 2 h, and the sintered carrier material has a total mass of 240 g. Take 1.523 g of palladium acetate and dissolve in 370 mL of tetrahydrofuran at room temperature, then pour the molded carrier material into the tetrahydrofuran solution of palladium acetate and vacuum stir dry. Finally, put the dried catalyst precursor into an atmosphere furnace and reduce at 300°C under Ar / H2 atmosphere. The reduced catalyst is named Y5, and the Pd content in Y5 catalyst is about 0.3%.
[0031] Put 180 g of Y5 catalyst into a fixed bed hydrogenation reactor, vacuum the fixed bed for a period of time, then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then use a metering pump to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under Y5 catalysis is >99%.
[0032] Put 180 g of Y5 catalyst into a fixed bed hydrogenation reactor, vacuum the fixed bed for a period of time, then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then use a metering pump to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under Y5 catalysis is >99%. Example 6
[0033] Take 23 g of polyvinylpyrrolidone PVP, dissolved in 370 mL of ethanol, and wait for the PVP to completely dissolve. Then transfer the PVP solution to a refrigerator and store it at 4°C for 0.5 h. Take 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al2O3, and disperse them in the PVP solution at room temperature. Place them in a vacuum sealed container and dry them by stirring under vacuum at room temperature. After the carrier is stirred to be sticky, place the carrier material in a granulator to form and granulate. Then dry the formed particles in a sealed container under vacuum. Then put the formed carrier particles into an atmosphere sintering furnace and sinter them at 700°C under H2atmosphere for 2 h. The sintered carrier material has a total mass of 240 g. Take 21.268 g of palladium acetylacetonate, and dissolve it in 370 mL of tetrahydrofuran at room temperature. Then pour the formed carrier material into the tetrahydrofuran solution of palladium acetylacetonate and dry it by stirring under vacuum. Finally, put the dried catalyst precursor into an atmosphere furnace and reduce it at 300°C under Ar / H2atmosphere. The reduced catalyst is named Y6, and the content of Pd in the Y6 catalyst is about 0.3%.
[0034] Put 180 g of Y6 catalyst into a fixed-bed hydrogenation reactor, and after the fixed bed is pumped to vacuum for a period of time, heat the reaction system to 150°C. Then, inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min using a metering pump, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that the conversion rate of N-ethylcarbazole in the fixed bed under Y6 catalysis is >99%.
[0035] Put 180 g of Y6 catalyst into a fixed-bed hydrogenation reactor, and after the fixed bed is pumped to vacuum for a period of time, heat the reaction system to 150°C. Then, inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min using a metering pump, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that the conversion rate of N-ethylcarbazole in the fixed bed under Y6 catalysis is >99%. Example 7
[0036] Take 23 g of polyvinylpyrrolidone PVP, dissolve in 370 mL of ethanol, wait for PVP to completely dissolve, transfer the PVP solution to the refrigerator and refrigerate at 4°C for 0.5 h. Take 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al2O3 and disperse in the PVP solution taken out at room temperature. Place in a vacuum sealed container and dry under vacuum while stirring at room temperature. After the carrier is stirred to be sticky, place the carrier material in a granulator for molding and granulation. Then dry the molded particles in a sealed container under vacuum. Put the molded carrier particles into an atmosphere sintering furnace and sinter at 700°C under H2 atmosphere for 2 h. The sintered carrier material has a total mass of 240 g. Take 297.27 g of nickel nitrate hexahydrate and dissolve in 370 mL of tetrahydrofuran at room temperature, then pour the molded carrier material into the tetrahydrofuran solution of nickel nitrate and vacuum stir dry. Finally, put the dried catalyst precursor into an atmosphere furnace and reduce at 450°C under Ar / H2 atmosphere. The reduced catalyst is named Y7, and the content of Ni in Y7 catalyst is about 20%.
[0037] Put 180 g of Y7 catalyst into a fixed bed hydrogenation reactor, vacuum the fixed bed for a period of time, then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then use a metering pump to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under Y7 catalysis is >99%.
[0038] Put 180 g of Y7 catalyst into a fixed bed hydrogenation reactor, vacuum the fixed bed for a period of time, then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then use a metering pump to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under Y7 catalysis is >99%. Example 8
[0039] Take 23 g of polyvinylpyrrolidone PVP, dissolve in 370 mL of ethanol, wait for PVP to completely dissolve, transfer the PVP solution to the refrigerator and refrigerate at 4°C for 0.5 h. Take 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al2O3 and disperse in the PVP solution taken out at room temperature. Place in a vacuum sealed container and dry under vacuum while stirring at room temperature. After the carrier is stirred to be sticky, place the carrier material in a granulator for molding and granulation. Then dry the molded particles in a sealed container under vacuum. Put the molded carrier particles into an atmosphere sintering furnace and sinter at 700°C under H2 atmosphere for 2 h. The sintered carrier material has a total mass of 240 g. Take 62.584 g of nickel nitrate hexahydrate and dissolve in 370 mL of tetrahydrofuran at room temperature, then pour the molded carrier material into the tetrahydrofuran solution of nickel nitrate and vacuum stir dry. Finally, put the dried catalyst precursor into an atmosphere furnace and reduce at 600°C under Ar / H2 atmosphere. The reduced catalyst is named Y8, and the content of Ni in Y8 catalyst is about 5%.
[0040] Put 180 g of Y8 catalyst into a fixed bed hydrogenation reactor, vacuum the fixed bed for a period of time, then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then use a metering pump to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under Y8 catalysis is >99%.
[0041] Put 180 g of Y8 catalyst into a fixed bed hydrogenation reactor, vacuum the fixed bed for a period of time, then heat the reaction system to 150°C, and then circulate 8 MPa of hydrogen into the reaction system. Then use a metering pump to inject N-ethylcarbazole into the reactor at a flow rate of 1.5 mL / min, and the total reaction time is one hour. After the reaction is completed, take the product for chromatographic characterization. The results show that in the fixed bed, the conversion rate of N-ethylcarbazole under Y8 catalysis is >99%. Comparative Example 1
[0042] The same as Example 5 except that no rare earth hydride was added. 23 g of polyvinylpyrrolidone (PVP) was dissolved in 370 mL of ethanol. After the PVP was completely dissolved, the PVP solution was transferred to a refrigerator and stored at 4°C for 0.5 h. Then 240 g of liquid organic hydrogen carrier Al2O3 was dispersed in the PVP solution at room temperature. After stirring until the carrier material became viscous, it was placed in a granulator to form granules. The formed granules were then dried in a vacuum oven in a sealed container. The formed carrier granules were then placed in an atmosphere sintering furnace and sintered at 700°C in a H2atmosphere for 2 h. The sintered carrier material had a total mass of 240 g. Then 1.523 g of palladium acetate was dissolved in 370 mL of tetrahydrofuran at room temperature, and the formed carrier material was then poured into the tetrahydrofuran solution of palladium acetate and stirred and dried under vacuum. Finally, the dried catalyst precursor was placed in an atmosphere furnace and reduced at 300°C in an Ar / H2atmosphere. The reduced catalyst was designated as YD1, and the content of Pd in the YD1 catalyst was about 0.3%.
[0043] 180 g of YD1 catalyst was placed in a fixed-bed hydrogenation reactor. After the fixed bed was evacuated and maintained at a vacuum for a period of time, the reaction system was heated to 150°C, and then 8 MPa of hydrogen was circulated into the reaction system. Then, N-ethylcarbazole was injected into the reactor at a flow rate of 1.5 mL / min using a metering pump, and the total reaction time was one hour. After the reaction was completed, the product was subjected to chromatographic characterization. The results showed that in the fixed bed, the conversion rate of N-ethylcarbazole under YD1 catalysis was >99%.
[0044] 180 g of YD1 catalyst was placed in a fixed-bed hydrogenation reactor. After the fixed bed was evacuated and maintained at a vacuum for a period of time, the reaction system was heated to 150°C, and then 8 MPa of hydrogen was circulated into the reaction system. Then, N-ethylcarbazole was injected into the reactor at a flow rate of 1.5 mL / min using a metering pump, and the total reaction time was one hour. After the reaction was completed, the product was subjected to chromatographic characterization. The results showed that in the fixed bed, the conversion rate of N-ethylcarbazole under YD1 catalysis was >99%. Comparative Example 2
[0045] The solvent for the binder is water, and the rest is the same as in Example 5. 23 g of polyvinylpyrrolidone PVP is dissolved in 370 mL of water, and after the PVP is completely dissolved, the PVP solution is transferred to a refrigerator and refrigerated at 4°C for 0.5 h. 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al2O3 are dispersed in the PVP solution taken out at room temperature. It is placed in a vacuum sealed container and dried while stirring under vacuum at room temperature. After the carrier is stirred to be sticky, the carrier material is placed in a granulator to be shaped and granulated. Then the shaped granules are vacuum dried in a sealed container. However, during the drying process, it is found that since the solvent in the binder is water, the volatilization speed of water is slow, and YH3 reacts slowly with water. As the water volatilizes slowly, the reaction time of YH3 with water is prolonged, causing the shaped carrier granules to gradually powder. This makes the catalyst carrier material for the fixed bed lose its due function. Comparative Example 3
[0046] The solvent for the noble metal / non-noble metal salt is water, and the rest is the same as in Example 5. 23 g of polyvinylpyrrolidone PVP is dissolved in 370 mL of ethanol, and after the PVP is completely dissolved, the PVP solution is transferred to a refrigerator and refrigerated at 4°C for 0.5 h. 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al2O3 are dispersed in the PVP solution taken out at room temperature. It is placed in a vacuum sealed container and dried while stirring under vacuum at room temperature. After the carrier is stirred to be sticky, the carrier material is placed in a granulator to be shaped and granulated. Then the shaped granules are vacuum dried in a sealed container. The shaped carrier granules are then placed in an atmosphere sintering furnace and sintered at 700°C in a H2 atmosphere for 2 h. The sintered carrier material has a total mass of 240 g. 1.523 g of palladium acetate is dissolved in 370 mL of water at room temperature, and then the shaped carrier material is poured into the aqueous palladium acetate solution and vacuum stirred and dried. During the drying process, it is found that the carrier material has been powdered. The powdering principle is the same as in Comparative Example 2. Comparative Example 4
[0047] The binder was not refrigerated, and the rest was the same as in Example 5. 23 g of polyvinylpyrrolidone PVP was dissolved in 370 mL of ethanol, and after the PVP was completely dissolved, 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al203 were dispersed in the PVP solution at room temperature. It was placed in a vacuum sealed container and dried by stirring under vacuum at room temperature. After the carrier was stirred to be sticky, the carrier material was placed in a granulator for molding and granulation. Then the molded particles were vacuum dried in a sealed container. During this process, the phenomenon of carrier pulverization was also found. This is because the temperature of the mixed system is low when the refrigerated binder is mixed with YH3, which does not give YH3 enough time to undergo alcoholysis reaction with ethanol before the solvent is completely volatilized. YH3 can be fully mixed with the binder, thereby exerting the best binding effect of the binder. The binder that has not been refrigerated still has the risk of causing YH3 to pulverize. Comparative Example 5
[0048] The binder solution was stirred and dried in an air environment at room temperature, and the rest was the same as in Example 5. 23 g of polyvinylpyrrolidone PVP was dissolved in 370 mL of ethanol, and after the PVP was completely dissolved, the PVP solution was transferred to a refrigerator and refrigerated at 4°C for 0.5 h. Then 54 g of YH3 and 180 g of liquid organic hydrogen carrier Al203 were dispersed in the PVP solution taken out at room temperature. The mixed suspension was stirred and dried in an air environment at room temperature. During the stirring process, it was found that YH3 gradually pulverized due to the influence of oxygen and humidity in the air environment. Further molding process found that it had already been impossible to mold. Comparative Example 6
[0049] The molded carrier material was not sintered, and the rest was the same as in Example 5. 23 g of polyvinylpyrrolidone PVP was dissolved in 370 mL of ethanol, and after the PVP was completely dissolved, the PVP solution was transferred to a refrigerator and refrigerated at 4°C for 0.5 h. Then 54 g of YH3 and 180 g of Al203 were dispersed in the PVP solution taken out at room temperature. It was placed in a vacuum sealed container and dried by stirring under vacuum at room temperature. After the carrier was stirred to be sticky, the carrier material was placed in a granulator for molding and granulation. Then the molded particles were vacuum dried in a sealed container, and the total mass of the molded carrier material was 240 g. 1.523 g of palladium acetate was taken and dissolved in 370 mL of tetrahydrofuran at room temperature, and then the molded carrier material was poured into the tetrahydrofuran solution of palladium acetate for vacuum stirring and drying. During the stirring process, it was found that the binder was dissolved in the tetrahydrofuran solution, and the molded carrier material was pulverized.
Claims
1. A method for forming a catalyst for hydrogen adsorption and desorption on a liquid organic hydrogen support in a fixed-bed reactor, characterized in that: The molding method includes the following steps: 1) Dissolve the adhesive in an appropriate amount of solvent ethanol or acetone to prepare an adhesive solution, and then refrigerate the adhesive solution; 2) Pour the refrigerated binder solution, rare earth metal hydride and liquid organic hydrogen carrier into a sealed container and stir under vacuum at room temperature to obtain a mixture; after the mixture becomes viscous, take it out and granulate it. 3) The shaped and granulated carrier material containing rare earth metal hydrides is placed in an atmosphere furnace and sintered at high temperature at 600~800℃; 4) The carrier material after high-temperature sintering is immersed in a Pd, Ru or Ni salt solution and dried under vacuum stirring at room temperature; the solvent of the Pd, Ru or Ni salt solution is a volatile solvent selected from ethanol, acetone or tetrahydrofuran. 5) The dried support material is reduced under H2 or Ar / H2 conditions at 300℃~600℃ to obtain the catalyst.
2. The catalyst forming method according to claim 1, characterized in that: The refrigeration conditions described in step 1) are: refrigeration temperature 4-10℃, refrigeration time 0.5-1h.
3. The catalyst forming method according to claim 1, characterized in that: The adhesive mentioned in step 1) is sodium carboxymethyl cellulose or polyvinylpyrrolidone.
4. The catalyst forming method according to claim 1, characterized in that: The rare earth metal hydride mentioned in step 2) is one or both of YH2 or YH3.
5. The catalyst forming method according to claim 1, characterized in that: The liquid organic hydrogen carrier mentioned in step 2) is Al2O3 or TiO2.
6. The catalyst forming method according to claim 1, characterized in that: The volume ratio of the solvent ethanol or acetone to the rare earth metal hydride is (0.685~21.5):1; the mass ratio of the binder to the liquid organic hydrogen carrier is (1.1~4):20; and the mass ratio of the rare earth metal hydride to the liquid organic hydrogen carrier material is (1~10):
10.
7. The catalyst forming method according to claim 1, characterized in that: The Ru salt is selected from one or more of ruthenium acetate, ruthenium dodecylcarbonyl, or ruthenium acetylacetonate; the Pd salt is selected from one or more of palladium nitrate, palladium acetate, or palladium acetylacetonate; and the Ni salt is nickel nitrate.
8. The catalyst forming method according to claim 1, characterized in that: When a Ni salt solution is selected, the non-precious metal Ni accounts for 5-20% of the total mass of the catalyst; when a Pd or Ru salt solution is selected, the precious metals Pd and Ru account for 0.3-3% of the total mass of the catalyst.