Low-cost catalyst for continuous hydrogenation of liquid-phase organic hydrogen carrier as well as preparation method and application of low-cost catalyst

Abstract

The invention relates to a low-cost catalyst for liquid-phase organic hydrogen carrier continuous hydrogenation and a preparation method and application thereof, the low-cost catalyst comprises an alumina carrier and an active non-noble metal component, and the reduction degree of the active non-noble metal component is not less than 80%. Compared with self-made and commercial ruthenium and palladium catalysts, the low-cost catalyst provided by the invention can achieve higher hydrogenation efficiency under the same reaction conditions, and the usage amount and cost of the catalyst are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of organic catalysis, and in particular to a low-cost catalyst for continuous hydrogenation of a liquid-phase organic hydrogen carrier, and a preparation method and application thereof. Background Art

[0002] Hydrogen energy is a clean energy with zero carbon emissions. The development of hydrogen storage and transportation technology plays an important role in realizing the application of hydrogen energy. The storage and transportation of hydrogen energy mainly include solid hydrogen storage, high-pressure gaseous hydrogen storage and organic liquid hydrogen storage. Organic liquid hydrogen storage technology is an emerging method of hydrogen energy storage and transportation. It has the characteristics of convenient transportation, high hydrogen storage density and high safety, and is expected to solve the current problem of long-distance transportation of hydrogen. Organic liquid hydrogen storage technology uses liquid organic hydrogen carriers and hydrogen to undergo a reversible chemical reaction under the action of a catalyst to generate alkane compounds to achieve hydrogen storage and release. The liquid organic hydrogen carriers under research include cycloalkanes, carbazoles, N-heterocycles, etc. Among them, dibenzyltoluene has become a liquid organic hydrogen carrier with great application potential due to its high hydrogen storage density, low cost (commonly used heat transfer oil in industry), non-flammable, non-explosive, non-volatile, and low melting point.

[0003] Currently, most dibenzyltoluene hydrogenation reactions use precious metal catalysts, which have problems such as low hydrogenation efficiency and expensive catalysts. The literature (International Journal of Hydrogen Energy, 46 (7), 5520-5529; Korean J. Chem. Eng. 2023, 40, 97–103; Fuel, 2022, 313, 122654) uses Sigma-Aldrich's commercial 5wt% Ru / Al2O3 catalyst to carry out dibenzyltoluene hydrogenation in a batch reactor, but the catalyst is very expensive. Raney nickel catalyst is a traditional hydrogenation catalyst. The literature (Materials Today: Proceedings, 2021, 45, 1123-1127) compared the hydrogenation reaction activity of dibenzyltoluene with three catalysts: 5% Ru / Al2O3, 5% Pd / Al2O3 and Raney nickel (Raney-Ni) in a reactor. The order of hydrogenation activity is: Raney-Ni>5% Pd / Al2O3>5% Ru / Al2O3. However, Raney nickel catalyst will spontaneously ignite when exposed to air, which is very dangerous. It needs to be handled with caution during use and post-reaction processing, which greatly increases the safety risks of actual production.

[0004] In summary, the use of precious metals and high loading are not conducive to industrial applications, and the hydrogenation efficiency needs to be improved. Furthermore, most of the current research on dibenzyltoluene is focused on intermittent reactors, which have problems such as complex operation and being unfavorable for continuous scale-up production. It is necessary to develop hydrogenation catalysts and corresponding processes suitable for continuous production. Summary of the invention

[0005] In order to solve the above technical problems, the present invention applies non-precious metal catalysts to the hydrogenation reaction of liquid organic hydrogen storage carriers to achieve continuous, high-efficiency and low-cost catalysis.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a low-cost catalyst for continuous hydrogenation of a liquid-phase organic hydrogen carrier, wherein the low-cost catalyst comprises an alumina carrier and an active non-precious metal component, wherein the active non-precious metal component is uniformly loaded on the alumina carrier, and the reduction degree of the active non-precious metal component is not less than 80%, for example, it can be 80%, 85%, 90%, 95% or 100%, etc.

[0008] The present invention significantly reduces the catalyst cost by using non-precious metal catalysts for the hydrogenation reaction of liquid organic hydrogen storage carriers, improves the hydrogenation catalytic efficiency by regulating the high reduction degree of active components on the catalyst surface, solves the problems of high cost and low catalytic efficiency of using precious metal catalysts in the prior art, and achieves the technical effect of high-efficiency and low-cost catalysis.

[0009] As a preferred technical solution of the present invention, the average particle size of the active non-precious metal component is 3 to 8 nm, for example, it can be 3 nm, 4 nm, 5 nm, 6 nm, 7 nm or 8 nm.

[0010] Preferably, the active non-precious metal component comprises Ni.

[0011] Preferably, the alumina carrier includes any one of α-Al 2 O 3 , θ-Al 2 O 3 , and γ-Al 2 O 3 , or a combination of at least two of them.

[0012] The present invention optimizes the average particle size of the active non-precious metal components on the catalyst surface so that the active non-precious metal components on the catalyst surface can be fully utilized in the hydrogenation reaction, thereby avoiding the low utilization rate of the active components caused by the excessive size of the metal particles on the catalyst surface, improving the hydrogenation activity of the catalyst, and achieving the technical effect of using non-precious metals to achieve a good catalytic hydrogenation effect while reducing the cost of the catalytic hydrogenation reaction.

[0013] As a preferred technical solution of the present invention, the loading amount of the active non-precious metal component is 10-30wt%, for example, it can be 10wt%, 15wt%, 20wt%, 25wt% or 30wt%.

[0014] The present invention optimizes the loading amount of active non-precious metal components on the catalyst so that the active non-precious metal components are uniformly distributed on the surface of the alumina carrier while maintaining an appropriate particle size. When the loading amount of the active non-precious metal components on the catalyst surface is too low, low catalytic hydrogenation activity due to insufficient active substances is likely to occur. When the loading amount of the active precious metal components on the catalyst surface is too high, a large amount of active components are likely to agglomerate, resulting in low utilization of the surface active components.

[0015] In a second aspect, the present invention provides a method for preparing the low-cost catalyst according to the first aspect, characterized in that the method comprises the following steps:

[0016] (1) loading a precursor solution of an active non-noble metal component on the surface of an alumina support by at least one wet impregnation and drying process to obtain a precursor support;

[0017] (2) The precursor support is subjected to reduction treatment to obtain the low-cost catalyst.

[0018] Compared with the conventional catalyst preparation method, the method for preparing the low-cost catalyst described in the first aspect provided by the present invention does not include a calcination step. Calcination causes the metal to form a metaaluminate on the alumina carrier that is difficult to reduce, and is more likely to aggregate on the surface of the alumina carrier. Therefore, not including a calcination step during the preparation process can make the prepared catalyst have a higher degree of reduction, and the reduced Ni metal has a smaller particle size. Both a high degree of reduction and a small particle size can improve the utilization rate of active metals in the catalyst in the hydrogenation reaction, and improve the catalytic activity of the catalyst under the same loading amount.

[0019] As a preferred technical solution of the present invention, the precursor solution in step (1) is a mixed solution of a metal precursor dissolved in an organic solvent and pure water.

[0020] Preferably, the metal precursor comprises nickel nitrate.

[0021] Preferably, the organic solvent includes any one of ethanol, methanol, isopropanol or tetrahydrofuran.

[0022] Preferably, the volume content of the organic solvent in the mixed solution is 5-70%, for example, 5%, 10%, 30%, 50% or 70%.

[0023] As a preferred technical solution of the present invention, the single impregnation time of the at least one wet impregnation in step (1) is 2 to 40 hours, for example, it can be 2 hours, 5 hours, 10 hours, 20 hours or 40 hours.

[0024] The present invention preferably adopts a method of repeating low-concentration impregnation and drying steps when the loading amount is greater than or equal to 20wt% to ensure the effective loading amount, reduce the agglomeration phenomenon caused by a one-time impregnation of a high-content metal precursor, and improve the uniformity of the distribution of the active non-precious metal component precursor on the catalyst surface.

[0025] As a preferred technical solution of the present invention, the drying in step (1) includes rotary evaporation, first drying and second drying performed sequentially.

[0026] Preferably, the pressure of the rotary evaporation is -0.10 to -0.05 MPa, for example, it may be -0.10 MPa, -0.09 MPa, -0.08 MPa, -0.07 MPa, -0.06 MPa or -0.05 MPa.

[0027] Preferably, the temperature of the rotary evaporation is 40-70°C, for example, 40°C, 45°C, 50°C, 60°C or 70°C.

[0028] Preferably, the rotary evaporation time is 10 to 30 min, for example, 10 min, 15 min, 20 min, 25 min, or 30 min.

[0029] Preferably, the first drying temperature is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C.

[0030] Preferably, the first drying time is 2 to 20 hours, for example, 2 hours, 5 hours, 10 hours, 15 hours or 20 hours.

[0031] Preferably, the second drying temperature is 100-120°C, for example, 100°C, 105°C, 110°C, 115°C or 120°C.

[0032] Preferably, the second drying time is not less than 12 hours, for example, it can be 12 hours, 15 hours, 20 hours, 25 hours or 30 hours.

[0033] The present invention further prefers that the drying is staged drying, firstly removing most of the solvent by rotary evaporation under negative pressure conditions, then drying at a relatively low temperature of 60-80°C, and when only a trace amount of solvent remains, drying at 100-120°C to fully remove the solvent, thereby avoiding a large amount of accumulation of active non-precious metal component precursors on the surface of the alumina carrier caused by the action of the solvent under high temperature conditions during a one-time high-temperature drying.

[0034] As a preferred technical solution of the present invention, the reduction treatment in step (2) uses hydrogen or a mixture of hydrogen and nitrogen as the reducing gas.

[0035] Preferably, the hydrogen content of the reducing gas is 5-100%, for example, 5%, 10%, 20%, 50%, 80% or 100%.

[0036] Preferably, the volume space velocity of the reducing gas is 300 to 1800 h -1 , for example, it can be 300h -1 , 500h -1 、1000h -1 , 1200h -1 、1500h -1 , or 1800h -1 wait.

[0037] Preferably, the pressure of the reduction treatment is 0.1-2.0 MPa, for example, 0.1 MPa, 0.5 MPa, 1.0 MPa, 1.5 MPa or 2.0 MPa.

[0038] Preferably, the temperature of the reduction treatment is 400-700°C, for example, 400°C, 450°C, 500°C, 600°C or 700°C.

[0039] Preferably, the heating rate of the reduction treatment is 1 to 15°C / min, for example, 1°C / min, 3°C / min, 5°C / min, 10°C / min or 15°C / min.

[0040] Preferably, the reduction treatment time is 1 to 12 hours, for example, 1 hour, 5 hours, 8 hours, 10 hours or 12 hours.

[0041] The present invention further optimizes the conditions for catalyst reduction, wherein the catalyst performance is greatly affected by the reduction temperature. When the reduction temperature is too low, insufficient reduction is likely to occur, and most of the unreduced active non-precious metal components cannot exert catalytic activity. When the reduction temperature is too high, the active non-precious metal components on the surface of the alumina carrier agglomerate in large quantities, the particle size of the active non-precious metal components increases, the utilization rate decreases, and the activity decreases. Within the preferred reduction temperature range of 400 to 700°C of the present invention, the catalyst can achieve better catalytic effect.

[0042] In a third aspect, the present invention provides an application of the low-cost catalyst described in the first aspect, wherein the application includes hydrogenation of a liquid organic hydrogen storage carrier.

[0043] As a preferred technical solution of the present invention, the liquid organic hydrogen storage carrier includes any one of dibenzyltoluene, benzyltoluene, toluene, benzene, biphenyl, naphthalene, N-ethylcarbazole or N-propylcarbazole, preferably dibenzyltoluene.

[0044] Compared with the prior art, the present invention has at least the following beneficial effects:

[0045] (1) The present invention applies non-precious metal catalysts to the hydrogenation reaction of liquid organic hydrogen storage carriers. In a continuous fixed bed reactor, compared with palladium, ruthenium-based and other precious metal hydrogenation catalysts, the nickel catalyst of the present invention has higher hydrogenation activity, and the hydrogenation degree of dibenzyltoluene can reach up to 98.8%, which greatly reduces the catalyst cost of the liquid organic hydrogen storage carrier hydrogenation reaction and improves the catalytic efficiency.

[0046] (2) The preferred preparation conditions of the present invention enable the prepared catalyst to have a higher degree of reduction and a suitable metal particle size, further improving the catalytic effect of the non-precious metal catalyst in the hydrogenation reaction of the liquid organic hydrogen storage carrier. DETAILED DESCRIPTION

[0047] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0048] Example 1

[0049] This embodiment provides a low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier, wherein the active non-metallic component is Ni, the Ni loading is 30wt%, the Ni reduction degree is 96%, and the average particle size of the Ni particles is 8.0nm. The catalyst is prepared by a wet impregnation method, and the specific preparation steps include:

[0050] 74.26g of nickel nitrate was dissolved in a mixed solution of 100mL of ethanol and water (ethanol volume ratio was 50%), sprayed on 100g of alumina support, impregnated at room temperature for 24h, transferred to a rotary evaporator and evaporated at 55℃ for 20min to remove the solvent, then dried in an oven at 60℃ for 3h and in an oven at 120℃ for 12h. The obtained precursor support had a loading of 15wt%, and the above impregnation and drying steps were repeated to obtain a precursor support with a loading of 30wt%.

[0051] Before the reaction, the catalyst was reduced and activated in situ using hydrogen in a fixed bed reactor. The specific conditions were as follows: 3.3 mL of catalyst and 10 g of quartz sand were filled, pure hydrogen (>99.999% purity) was used as the reducing gas, and the volumetric space velocity was 1800 h -1The reduction temperature is 500°C, the reduction adopts programmed temperature rise and the heating rate is controlled at 5°C / min, the reduction pressure is 0.5MPa, the reduction time is 6h, and the hydrogenation reaction is directly carried out in the fixed bed reactor after the reduction is completed. The reaction raw material is dibenzyltoluene (effective ingredient ≥98%), the reaction pressure is 5MPa, the reaction temperature is 200°C, and the hydrogen volume space velocity is 4500h -1 , the liquid volume space velocity is 3h -1 .

[0052] Example 2

[0053] This embodiment provides a low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier, wherein the active non-metallic component is Ni, the Ni loading is 20wt%, the Ni reduction degree is 93%, and the average particle size of the Ni particles is 5.5nm. The catalyst is prepared by a wet impregnation method, and the specific preparation steps include:

[0054] 99.01g of nickel nitrate was dissolved in a mixed solution of 100mL of ethanol and water (ethanol volume ratio was 5%), sprayed on 100g of alumina support, impregnated at room temperature for 2h, transferred to a rotary evaporator and evaporated at 70℃ for 10min to remove the solvent, then dried in an oven at 70℃ for 2h and in an oven at 110℃ for 15h. The obtained precursor support had a loading of 10wt%, and the above impregnation and drying steps were repeated to obtain a precursor support with a loading of 20wt%.

[0055] Before the reaction, the catalyst was reduced and activated in situ using hydrogen in a fixed bed reactor. The specific conditions were as follows: 3.3 mL of catalyst and 10 g of quartz sand were filled, and a mixture of hydrogen (>99.999% purity) and nitrogen was used as the reducing gas, in which the volume content of hydrogen was 50%, and the volumetric space velocity of the mixed gas was 300 h -1 The reduction temperature is 700°C, the reduction adopts programmed temperature rise and the heating rate is controlled at 15°C / min, the reduction pressure is 0.1MPa, the reduction time is 1h, and the hydrogenation reaction is directly carried out in the fixed bed reactor after the reduction is completed. The reaction raw material is dibenzyltoluene (effective ingredient ≥98%), the reaction pressure is 5MPa, the reaction temperature is 200°C, and the hydrogen volume space velocity is 4500h -1 , the liquid volume space velocity is 3h -1 .

[0056] Example 3

[0057] This embodiment provides a low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier, wherein the active non-metallic component is Ni, the Ni loading is 10wt%, the Ni reduction degree is 80%, and the average particle size of the Ni particles is 3.0nm. The catalyst is prepared by a wet impregnation method, and the specific preparation steps include:

[0058] 49.50 g of nickel nitrate was dissolved in a mixed solution of 100 mL of ethanol and water (ethanol volume ratio was 70%), sprayed on 100 g of alumina support, and after impregnation at room temperature for 40 h, transferred to a rotary evaporator and evaporated at 40 ° C for 30 min to remove the solvent, and then dried in an oven at 80 ° C for 20 h and in an oven at 120 ° C for 12 h. The loading amount of the obtained precursor support was 10 wt%.

[0059] Before the reaction, the catalyst was reduced and activated in situ using hydrogen in a fixed bed reactor. The specific conditions were as follows: 3.3 mL of catalyst and 10 g of quartz sand were filled, and a mixture of hydrogen (>99.999% purity) and nitrogen was used as the reducing gas, wherein the volume content of hydrogen was 5%, and the volumetric space velocity of the mixed gas was 1500 h -1 The reduction temperature is 400°C, the reduction adopts programmed temperature rise and the heating rate is controlled at 15°C / min, the reduction pressure is 2MPa, the reduction time is 12h, and the hydrogenation reaction is directly carried out in the fixed bed reactor after the reduction is completed. The reaction raw material is dibenzyltoluene (effective ingredient ≥98%), the reaction pressure is 5MPa, the reaction temperature is 200°C, and the hydrogen volume space velocity is 4500h -1 , the liquid volume space velocity is 3h -1 .

[0060] Example 4

[0061] The low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier provided in this embodiment is the same as that in Embodiment 1 except that the oven drying in the catalyst preparation is not segmented and the oven drying is performed at 100° C. for 24 hours.

[0062] Example 5

[0063] The low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier of this embodiment is the same as that of Example 1 except that the rotary evaporation step is not provided in the catalyst preparation, the oven drying is not segmented, and the oven drying is performed at 100° C. for 24 hours.

[0064] Example 6

[0065] The low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier in this embodiment is the same as that in Example 1 except that the Ni loading is 5 wt %.

[0066] Example 7

[0067] The low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier in this embodiment is the same as that in Example 1 except that the Ni loading is 40 wt%.

[0068] Example 8

[0069] The low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier of this embodiment is the same as that of Embodiment 1 except that the reduction temperature is 300°C.

[0070] Example 9

[0071] The low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier of this embodiment is the same as that of Embodiment 1 except that the reduction temperature is 800°C.

[0072] Comparative Example 1

[0073] This comparative example is the same as Example 1 except that the catalyst active metal precursor is ruthenium chloride and the loading amount of Ru is 1 wt %.

[0074] Comparative Example 2

[0075] This comparative example is the same as Example 1 except that the catalyst active metal precursor is palladium nitrate and the Pd loading is 1 wt %.

[0076] Comparative Example 3

[0077] This comparative example is the same as Example 1 except that the catalyst used is a commercial 5wt% Ru / Al2O3 catalyst (Product No.: 439916) purchased from Sigma-Aldrich.

[0078] Comparative Example 4

[0079] The low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier provided in this comparative example is the same as that in Example 1 except that it is calcined at 500° C. for 4 h after the drying step.

[0080] Test Method

[0081] The reaction activity of the catalyst was determined using a continuous fixed-bed reactor.

[0082] The hydrogenation reaction is carried out in a continuous fixed bed reactor, the liquid product is collected at regular intervals, and the hydrogenation degree of the liquid is tested by gas chromatography.

[0083] Liquid hydrogenation degree = hydrogen consumption of hydrogenated liquid product / theoretical maximum hydrogen consumption.

[0084] The degree of reduction of Ni metal was determined by the hydrogen consumption in a hydrogen temperature-programmed reduction test on a Micromeritics Autochem II 2920 chemisorption instrument.

[0085] Hydrogen temperature-programmed reduction test conditions: 100 mg of sample was placed in a quartz tube reactor, and Ar gas was first purged at 150°C for 1 hour to remove adsorbed water in the sample. After the temperature dropped to 50°C, it was switched to 10% H2 / Ar gas, and then raised to 800°C at a rate of 10°C / min. During the heating process, a cold trap mixed with isopropanol and liquid nitrogen was used to remove the generated water. A thermal conductivity detector (TCD) was used to detect the consumption of hydrogen.

[0086] The reduction degree of the active component nickel = actual hydrogen consumption / theoretical maximum hydrogen consumption.

[0087] The test results are shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091] "-" in the table means no data

[0092] The test results show that:

[0093] (1) It can be seen from Examples 1 to 3 that the present invention can achieve efficient catalytic hydrogenation of dibenzyltoluene by regulating the reduction degree of Ni metal on the catalyst surface to be not less than 80% and the particle size to be in the range of 3.0 to 8.0 nm, with a hydrogenation degree of more than 84%. Under optimal conditions, the hydrogenation degree can reach 98.8%.

[0094] (2) It can be seen from Examples 1 and 4 to 5 that the present invention reduces the agglomeration of Ni metal on the catalyst surface and reduces the particle size of Ni metal on the surface by staged drying. In Example 4, the oven drying is not staged and is dried in an oven at 100° C. for 24 h. Since a small amount of solvent remains after rotary evaporation, when step-by-step oven drying is not used, the agglomeration of Ni precursor on the surface is enhanced, and the particle size of Ni metal increases from 8.0 nm in Example 1 to 9.1 nm, resulting in a decrease in the degree of dehydrogenation from 98.8 in Example 1 to 86.4% in Example 4. When rotary evaporation is not provided in Example 5 and the oven is dried at 100° C. for 24 h, a large amount of solvent still remains on the catalyst surface. During the drying process, the Ni precursor agglomerates in large quantities, and the particle size of Ni metal increases to 12.2 nm, resulting in a sudden drop in the catalytic hydrogenation effect and a decrease in the degree of hydrogenation to 51.9%.

[0095] (3) It can be seen from Examples 1 and 6 to 7 that the loading amount of Ni metal on the preferred catalyst of the present invention achieves a better catalytic hydrogenation effect. When the loading amount of Ni in Example 6 is 5 wt%, the Ni metal active sites on the catalyst surface are insufficient, resulting in a decrease in the catalytic hydrogenation effect, and the degree of hydrogenation decreases to 57.9%. When the loading amount of Ni in Example 7 is 40 wt%, the agglomeration tendency of Ni metal on the catalyst surface increases, resulting in the average particle size of Ni metal particles on the prepared catalyst surface reaching 11.1 nm, the utilization rate of Ni metal is greatly reduced, and the degree of hydrogenation decreases to 65.2%.

[0096] (4) It can be seen from Examples 1 and 8 to 9 that the preferred reduction temperature of the catalyst of the present invention enables the catalyst to achieve a higher reduction degree while avoiding a large amount of agglomeration caused by high temperature, thereby achieving a better catalytic hydrogenation effect. When the reduction temperature in Example 8 is 300°C, the Ni metal on the surface of the catalyst cannot be fully reduced, and the reduction degree drops to 47%, resulting in a decrease in the hydrogenation degree to 62.5%; when the reduction temperature in Example 9 is 800°C, although the Ni metal on the surface of the catalyst maintains a high reduction degree, the Ni metal agglomerates in large quantities at high temperature, and the size of the Ni metal particles reaches 14.4nm, and the utilization rate of the Ni metal in the catalytic hydrogenation reaction decreases, resulting in a decrease in the catalytic hydrogenation effect, and the hydrogenation degree drops to 45.3%.

[0097] (5) It can be seen from Example 1 and Comparative Examples 1 to 3 that the nickel catalyst has a highly efficient catalytic effect in the hydrogenation reaction of dibenzyltoluene. In a continuous fixed bed reactor, at a reaction temperature of 200°C, compared with the commonly used 1wt% loading of palladium, ruthenium-based and other precious metal hydrogenation catalysts, the nickel catalyst of the present invention has a higher hydrogenation activity, and the hydrogenation degree of dibenzyltoluene can reach up to 98.8%.

[0098] (6) It can be seen from Example 1 and Comparative Example 4 that the present invention does not set a calcination step, so that the catalyst obtains a higher reduction degree, thereby improving the catalytic hydrogenation effect. Calcination will cause Ni metal to form nickel aluminate on the alumina carrier, which is difficult to reduce. At the same time, it is more likely to agglomerate on the surface of the alumina carrier, resulting in an increase in the Ni metal particle size on the catalyst surface. When a calcination step is set, the reduction degree of the catalyst is only 66%, and the average particle size of the surface metal particles is 8.5 nm, resulting in a decrease in the hydrogenation degree to 67.8%.

[0099] In summary, the present invention greatly reduces the catalyst cost by using non-precious metal catalysts for the hydrogenation reaction of liquid organic hydrogen storage carriers, improves the hydrogenation catalytic efficiency by regulating the higher reduction degree of the active components on the catalyst surface and optimizing the size of the metal particles on the catalyst surface, solves the problems of the cost of using precious metal catalysts and low catalytic efficiency in the prior art, and achieves the technical effect of high-efficiency and low-cost catalysis.

[0100] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A low-cost catalyst for continuous hydrogenation of a liquid organic hydrogen carrier, characterized in that: The low-cost catalyst comprises an alumina carrier and an active non-noble metal component, wherein the active non-noble metal component is uniformly loaded on the alumina carrier, and the reduction degree of the active non-noble metal component is not less than 80%.

2. The low-cost catalyst according to claim 1, characterized in that The average particle size of the active non-precious metal component is 3 to 8 nm; Preferably, the active non-precious metal component comprises Ni.

3. The low-cost catalyst according to claim 1 or 2, characterized in that The loading amount of the active non-noble metal component is 10 to 30 wt %.

4. A method for preparing the low-cost catalyst according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: (1) loading a precursor solution of an active non-noble metal component on the surface of an alumina support by at least one wet impregnation and drying process to obtain a precursor support; (2) The precursor support is subjected to reduction treatment to obtain the low-cost catalyst.

5. The method according to claim 4, characterized in that The precursor solution in step (1) is a mixed solution of a metal precursor dissolved in an organic solvent and pure water; Preferably, the metal precursor comprises nickel nitrate; Preferably, the organic solvent comprises any one of ethanol, methanol, isopropanol or tetrahydrofuran; Preferably, the volume content of the organic solvent in the mixed solution is 5-70%.

6. The method according to claim 4 or 5, characterized in that: The single impregnation time of the at least one wet impregnation in step (1) is 2 to 40 hours.

7. The method according to any one of claims 4 to 6, characterized in that: The drying in step (1) comprises rotary evaporation, first drying and second drying performed sequentially; Preferably, the rotary evaporation pressure is -0.10 to -0.05 MPa; Preferably, the temperature of the rotary evaporation is 40 to 70°C; Preferably, the rotary evaporation time is 10 to 30 minutes; Preferably, the first drying temperature is 60-80°C; Preferably, the first drying time is 2 to 20 hours; Preferably, the second drying temperature is 100-120°C; Preferably, the second drying time is not less than 12 hours.

8. The method according to any one of claims 4 to 7, characterized in that: The reduction treatment in step (2) uses hydrogen or a mixture of hydrogen and nitrogen as the reducing gas; Preferably, the hydrogen content of the reducing gas is 5 to 100%; Preferably, the volume space velocity of the reducing gas is 300 to 1800 h -1 ; Preferably, the pressure of the reduction treatment is 0.1-2.0 MPa; Preferably, the temperature of the reduction treatment is 400-700°C; Preferably, the heating rate of the reduction treatment is 1 to 15°C / min; Preferably, the reduction treatment time is 1 to 12 hours.

9. Use of a low-cost catalyst according to any one of claims 1 to 3, characterized in that: The application includes hydrogenation of liquid organic hydrogen storage carriers.

10. The use according to claim 9, characterized in that: The liquid organic hydrogen storage carrier includes any one of dibenzyltoluene, benzyltoluene, toluene, benzene, biphenyl, naphthalene, N-ethylcarbazole or N-propylcarbazole, preferably dibenzyltoluene.

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