Method for preparing supported catalyst

Abstract

The invention belongs to the technical field of catalysts, and discloses a method for preparing a supported catalyst. The method comprises the following steps: (1) carrying out pre-wetting treatment on a carrier by using a pre-wetting solution, and then carrying out first drying to obtain a pre-wetted carrier; and (2) dipping the pre-wetted carrier in a solution containing metal salt, and then sequentially carrying out second drying and roasting to obtain the supported catalyst, wherein the pre-wetting solution contains ammonium salt and / or cellulose. The preparation method can effectively reduce the loss of the loaded metal in the catalyst production process and save the production cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and particularly relates to a method for preparing a supported catalyst. Background Art

[0002] With the depletion of petroleum resources and the increasing social energy demand, the conversion of unconventional oils such as bio-oil, shale oil, and coal tar has gradually become a supplement and alternative to the existing energy system. However, a large amount of oxygen-containing compounds in unconventional oils reduces the stability and calorific value of the oils. Catalytic hydrodeoxygenation can improve the quality of oils by removing oxygen atoms from oxygen-containing compounds. The shaped multi-porous metal catalyst has been widely used in the hydrodeoxygenation reaction due to its excellent low-temperature activity and deoxygenation performance.

[0003] In the production process of the shaped multi-porous catalyst, the loss of the supported metal is likely to occur. The price of the supported metal is relatively high, and this loss phenomenon will lead to an increase in the production cost of the catalyst. Therefore, it is of great significance to develop a method that can effectively reduce the loss of the supported metal during the preparation of the supported catalyst. Summary of the Invention

[0004] Aiming at the problem that the supported metal in the existing preparation method of the supported catalyst is relatively easy to lose and has a large loss, the present invention provides a method for preparing a supported catalyst.

[0005] To achieve the above object, the present invention provides a method for preparing a supported catalyst, and the method includes:

[0006] (1) Pre-wetting the carrier with a pre-wetting solution, and then performing the first drying to obtain a pre-wetted carrier;

[0007] (2) Immersing the pre-wetted carrier in a solution containing a metal salt, and then successively performing the second drying and calcination to obtain a supported catalyst;

[0008] Wherein, the pre-wetting solution contains an ammonium salt and / or cellulose.

[0009] The method for preparing a supported catalyst provided by the present invention can achieve a loss of the supported metal during the preparation process of less than 3 wt% by adding a pre-wetting process for the carrier. Further, by optimizing the conditions of impregnation, drying, and calcination, a loss of the supported metal during the preparation process of less than 2 wt% can be achieved. Detailed Embodiments

[0010] The endpoints and any values disclosed in this text for a range are not limited to the exact range or value. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this text.

[0011] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention, and are not used to limit the present invention.

[0012] The present invention provides a method for preparing a supported catalyst, and the method includes:

[0013] (1) Using a pre-wetting solution to perform a pre-wetting treatment on a carrier, and then performing a first drying to obtain a pre-wetted carrier;

[0014] (2) Immersing the pre-wetted carrier in a solution containing a metal salt, and then sequentially performing a second drying and calcination to obtain a supported catalyst;

[0015] Wherein, the pre-wetting solution contains an ammonium salt and / or cellulose.

[0016] The inventors of the present invention found in the research that during the preparation process of the supported catalyst, using a pre-wetting solution containing an ammonium salt and / or cellulose to perform a pre-wetting treatment on the carrier, and then impregnating the pre-wetted carrier with a metal active component, the ammonium salt and / or cellulose in the pre-wetting solution can strengthen the loading effect between the metal and the carrier, improve the strength of the pre-wetted material, reduce the wear and fragmentation of the material in the subsequent process, and thus can effectively reduce the loss or wastage of the loaded metal in the subsequent catalyst production process (including drying, calcination, etc.).

[0017] According to the present invention, in the method for preparing the supported catalyst, in step (1), the ammonium salt contained in the pre-wetting solution can be selected from at least one of ammonium bicarbonate, ammonium chloride, ammonium sulfate, and ammonium nitrate. Preferably, the ammonium salt is selected from ammonium bicarbonate and / or ammonium nitrate, which is more conducive to reducing the loss or wastage of the loaded metal during the catalyst production process.

[0018] According to the present invention, in the method for preparing the supported catalyst, in step (1), the cellulose can be selected from at least one of methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose. Preferably, the cellulose is selected from methyl cellulose and / or hydroxypropyl methyl cellulose, which is more conducive to reducing the loss or wastage of the loaded metal during the catalyst production process.

[0019] According to the present invention, preferably, the molecular weight of the cellulose is 5000 - 60000 g / mol. Further, in some preferred embodiments of the present invention, the molecular weight of the methylcellulose is 10000 - 50000 g / mol, the molecular weight of the carboxymethylcellulose is 5400 - 7400 g / mol, the molecular weight of the hydroxyethylcellulose is 15000 - 30000 g / mol, and the molecular weight of the hydroxypropylmethylcellulose is 10000 - 60000 g / mol, which is more conducive to reducing the loss or wastage of the supported metal during the production of the catalyst.

[0020] According to the present invention, the pre-wetting solution can be prepared by mixing an ammonium salt and / or cellulose with a solvent. Preferably, the solvent can be selected from at least one of water, sodium hydroxide solution, and nitric acid solution, and more preferably water. Among the above solvents, preferably, the concentration of the sodium hydroxide solution is 0.1 - 0.5 wt%, and the concentration of the nitric acid solution is 0.1 - 0.5 wt%.

[0021] According to the present invention, in the method for preparing the supported catalyst, in step (1), the concentration of the ammonium salt in the pre-wetting solution can be 0.6 - 1.25 g / L. Whether the concentration of the ammonium salt is too low or too high is not conducive to further reducing the loss or wastage of the supported metal during the production of the catalyst. Preferably, in the pre-wetting solution, the concentration of the ammonium salt is 0.8 - 1 g / L.

[0022] According to the present invention, in the method for preparing the supported catalyst, in step (1), the concentration of the cellulose in the pre-wetting solution can be 0.1 - 0.5 g / L. Whether the concentration of the cellulose is too low or too high is not conducive to further reducing the loss or wastage of the supported metal during the production of the catalyst. Preferably, in the pre-wetting solution, the concentration of the cellulose is 0.15 - 0.3 g / L.

[0023] According to the present invention, in the method for preparing the supported catalyst, in step (1), the pre-wetting treatment can be achieved by immersing the carrier in the pre-wetting solution, or by spraying the pre-wetting solution on the surface of the carrier. Preferably, the method of immersing the carrier in the pre-wetting solution is adopted.

[0024] According to the present invention, in the method for preparing the supported catalyst, in step (1), the conditions of the pre-wetting treatment include: the temperature is 20 - 50 °C, and the time is 25 - 35 min.

[0025] According to the present invention, in the method for preparing the supported catalyst, in step (1), before the first drying, it is preferable to drain the pre-wetted carrier to effectively remove most of the pre-wetting solution adhering to the surface of the carrier.

[0026] According to the present invention, in step (1) of the method for preparing the supported catalyst, the conditions for the first drying include: the temperature is 30-65°C and the time is 1.5-3 h. Through the first drying, the solution on the surface of the pre-wetted support can be completely removed.

[0027] According to a preferred embodiment of the present invention, the first drying is carried out in a stepwise temperature-rising drying manner.

[0028] According to the present invention, in step (2) of the method for preparing the supported catalyst, during the impregnation process, preferably, the metal salt-containing solution is fed in sequence in the form of a first batch of impregnating solution and a second batch of impregnating solution. Specifically, the pre-wetted support can be first impregnated in the first batch of impregnating solution, and after impregnation for a certain time, the second batch of impregnating solution is added to the impregnation system to continue impregnation until the total impregnation time required is reached, and the impregnation process is ended.

[0029] According to the present invention, the first batch of impregnating solution accounts for 10-50% of the total weight of the metal salt-containing solution. If the proportion of the first batch of impregnating solution in the metal salt-containing solution is too low or too high, it is not conducive to further reducing the loss of the supported metal during the catalyst production process. Preferably, the first batch of impregnating solution accounts for 20-40% of the total weight of the metal salt-containing solution.

[0030] According to the present invention, the second batch of impregnating solution accounts for 50-90% of the total weight of the metal salt-containing solution, and more preferably 60-80%.

[0031] According to the present invention, the impregnation time of the first batch of impregnating solution is 10-40 min, preferably 20-30 min.

[0032] According to the present invention, the total impregnation time is 20-60 min, preferably 30-50 min.

[0033] In the present invention, the temperature for the impregnation is defined within a relatively wide range and can be selected conventionally. For example, it can be carried out at room temperature. In the present invention, room temperature refers to 25-35°C.

[0034] According to the present invention, in step (2) of the method for preparing the supported catalyst, the conditions for the second drying include: the temperature is 30-120°C and the time is 0.5-1.5 h.

[0035] According to a preferred embodiment of the present invention, the second drying is carried out in a stepwise temperature-rising drying manner, which is beneficial to reducing the loss of the supported metal.

[0036] According to the present invention, in the method for preparing the supported catalyst, in step (2), the conditions for calcination can be flexibly selected according to the type of the carrier and the type of the supported active metal component, and the present invention does not make specific limitations thereto. Preferably, the conditions for calcination include: the temperature is 400 - 650 °C, and the time is 1.5 - 3 h.

[0037] According to a preferred embodiment of the present invention, the calcination is carried out by means of programmed temperature calcination, which is beneficial to reducing the loss or consumption of the supported metal caused by the explosion of the material.

[0038] According to the present invention, in the method for preparing the supported catalyst, the limitation on the carrier is relatively wide, and the carrier used in conventional supported catalysts can be adopted. For example, the carrier can be selected from at least one of alumina, silica, and titanium dioxide, and preferably alumina.

[0039] According to the present invention, preferably, the specific surface area of the carrier is 150 - 200 m 2 / g, and the pore volume is 0.3 - 0.7 mL / g.

[0040] In the present invention, the carrier can be a commercially available product or can be obtained by self-making using a conventional method, and the present invention does not make specific limitations thereto.

[0041] According to the present invention, in the method for preparing the supported catalyst, the limitation on the metal salt is relatively wide. For example, the metal salt can be selected from at least one of molybdate, nickel salt, cobalt salt, platinum salt, and palladium salt, and preferably at least one of molybdate, nickel salt, and cobalt salt. The solution containing the metal salt is an aqueous solution containing the metal salt.

[0042] The method for preparing the catalyst provided by the present invention, on the basis of the existing preparation process of the supported catalyst, by adding a pre-wetting process for the carrier, it can be realized that the loss of the supported metal (calculated as the metal element) during the preparation process is less than 3 wt%. Further, by optimizing the conditions of impregnation, drying, and calcination, it can be realized that the loss of the supported metal during the preparation process is less than 2 wt%. The method provided by the present invention is particularly suitable for preparing a shaped multi-porous metal catalyst. Preferably, the carrier of the shaped multi-porous metal catalyst is alumina, and the supported active metal is selected from at least one of molybdenum, nickel, and cobalt. By using the method provided by the present invention to prepare this kind of shaped multi-porous metal catalyst, the loss of the supported metal during the preparation process can be greatly reduced, the preparation cost can be reduced, and the use effect of the catalyst can be improved.

[0043] The present invention will be described in detail below through examples. In the following examples and comparative examples, unless otherwise specified, the materials used are all ordinary commercially available products.

[0044] Example 1

[0045] (1) 380.0 g of aluminum hydroxide dry gel powder, 8.0 g of sesbania powder, 8.0 g of silica sol, 8.9 g of nitric acid (concentration 68 wt%), and 23.0 g of water were kneaded, then formed, and then dried at 45 °C for 1.5 h and calcined at 650 °C for 2.5 h in sequence to obtain a special-shaped multi-porous carrier (the component of this carrier is alumina, the specific surface area of this carrier is 180 m 2 / g, and the pore volume is 0.6 mL / g);

[0046] The above-prepared carrier was impregnated in a pre-wetting solution (the concentration of ammonium bicarbonate is 0.85 g / L, the concentration of methyl cellulose (molecular weight 20000 g / mol) is 0.15 g / L, and the solvent is water) for pre-wetting treatment (temperature 30 °C, time 30 min); the carrier after pre-wetting treatment was drained, and then subjected to first drying (using a stepwise temperature-rising drying method, drying at 35 °C for 0.5 h, 45 °C for 1.5 h, and 55 °C for 0.5 h in sequence) to obtain a pre-wetted carrier;

[0047] (2) 183.8 g of nickel nitrate was dissolved in 238 g of water to prepare a salt solution, and this salt solution was divided into a first batch of impregnation solution (accounting for 25% of the total weight of the salt solution) and a second batch of impregnation solution (accounting for 75% of the total weight of the salt solution);

[0048] The pre-wetted carrier obtained in step (1) was impregnated in the above first batch of impregnation solution (impregnation temperature 30 °C, impregnation time 20 min), and then the above second batch of impregnation solution was added to the impregnation system to continue impregnation (impregnation temperature 30 °C), and the total impregnation time was 35 min;

[0049] The above-impregnated carrier was subjected to second drying (using a stepwise temperature-rising drying method, drying at 60 °C for 0.5 h, 80 °C for 0.5 h, and 100 °C for 0.5 h in sequence), and then calcined (using a programmed temperature-rising calcination method, calcining at 400 °C for 0.5 h, 500 °C for 0.5 h, and 550 °C for 1.0 h in sequence) to obtain a catalyst (denoted as C1).

[0050] Example 2

[0051] (1) 380.0 g of aluminum hydroxide dry gel powder, 8.0 g of sesbania powder, 8.0 g of silica sol, 8.9 g of nitric acid (concentration 68 wt%), and 23.0 g of water were kneaded, then formed, and then dried at 45 °C for 1.5 h and calcined at 650 °C for 2.5 h in sequence to obtain a special-shaped multi-porous carrier (the component of this carrier is alumina, the specific surface area of this carrier is 180 m 2 / g, and the pore volume is 0.6 mL / g);

[0052] The carrier prepared above was impregnated in a pre-wetting solution (the concentration of ammonium bicarbonate was 0.95 g / L, the concentration of methyl cellulose (molecular weight 20,000 g / mol) was 0.25 g / L, and the solvent was water) for pre-wetting treatment (temperature was 30 °C, time was 30 min); the carrier after pre-wetting treatment was drained, and then subjected to the first drying (using a stepwise temperature-rising drying method, drying at 35 °C for 0.5 h, 45 °C for 1.5 h, and 55 °C for 0.5 h in sequence) to obtain the pre-wetted carrier;

[0053] (2) 183.8 g of nickel nitrate was dissolved in 238 g of water to form a salt solution, and this salt solution was divided into a first batch impregnation solution (accounting for 35% of the total weight of the salt solution) and a second batch impregnation solution (accounting for 65% of the total weight of the salt solution);

[0054] The pre-wetted carrier obtained in step (1) was impregnated in the above-mentioned first batch impregnation solution (impregnation temperature was 30 °C, impregnation time was 30 min), and then the above-mentioned second batch impregnation solution was added to the impregnation system to continue impregnation (impregnation temperature was 30 °C), and the total impregnation time was 45 min;

[0055] The impregnated carrier was subjected to the second drying (using a stepwise temperature-rising drying method, drying at 60 °C for 0.5 h, 80 °C for 0.5 h, and 100 °C for 0.5 h in sequence), and then calcined (using a programmed temperature-rising calcination method, calcining at 400 °C for 0.5 h, 500 °C for 0.5 h, and 550 °C for 1.0 h in sequence) to obtain a catalyst (denoted as C2).

[0056] Example 3

[0057] (1) 380.0 g of aluminum hydroxide dry gel powder, 8.0 g of talc powder, 8.0 g of silica sol, 8.9 g of nitric acid (concentration 68 wt%), and 23.0 g of water were kneaded, then shaped, and then dried at 45 °C for 1.5 h and calcined at 650 °C for 2.5 h in sequence to obtain a shaped multi-porous carrier (the component of this carrier was alumina, the specific surface area of this carrier was 180 m 2 / g, and the pore volume was 0.6 mL / g);

[0058] The carrier prepared above was impregnated in a pre-wetting solution (the concentration of ammonium chloride was 0.70 g / L, the concentration of carboxymethyl cellulose (molecular weight 6400 g / mol) was 0.12 g / L, and the solvent was water) for pre-wetting treatment (temperature 30 °C, time 30 min); the carrier after pre-wetting treatment was drained, and then subjected to first drying (using a stepwise temperature-raising drying method, drying at 35 °C for 0.5 h, 45 °C for 1.5 h, and 55 °C for 0.5 h in sequence) to obtain the pre-wetted carrier;

[0059] (2) 183.8 g of nickel nitrate was dissolved in 238 g of water to prepare a salt solution, and this salt solution was divided into a first batch of impregnation solution (accounting for 15% of the total weight of the salt solution) and a second batch of impregnation solution (accounting for 85% of the total weight of the salt solution);

[0060] The pre-wetted carrier obtained in step (1) was impregnated in the above-mentioned first batch of impregnation solution (impregnation temperature 30 °C, impregnation time 12 min), and then the above-mentioned second batch of impregnation solution was added to the impregnation system to continue impregnation (impregnation temperature 30 °C), with a total impregnation time of 27 min;

[0061] The impregnated carrier above was subjected to second drying (using a stepwise temperature-raising drying method, drying at 60 °C for 0.5 h, 80 °C for 0.5 h, and 100 °C for 0.5 h in sequence), and then calcined (using a programmed temperature-raising calcination method, calcining at 400 °C for 0.5 h, 500 °C for 0.5 h, and 550 °C for 1.0 h in sequence) to obtain a catalyst (denoted as C3).

[0062] Example 4

[0063] (1) 380.0 g of aluminum hydroxide dry gel powder, 8.0 g of talc powder, 8.0 g of silica sol, 8.9 g of nitric acid (concentration 68 wt%), and 23.0 g of water were kneaded, then formed, and then dried at 45 °C for 1.5 h and calcined at 650 °C for 2.5 h in sequence to obtain a shaped multi-porous carrier (the component of this carrier was alumina, the specific surface area of this carrier was 180 m 2 / g, and the pore volume was 0.6 mL / g);

[0064] The carrier prepared above was impregnated in a pre-wetting solution (the concentration of ammonium chloride was 1.20 g / L, the concentration of carboxymethyl cellulose (molecular weight 6400 g / mol) was 0.40 g / L, and the solvent was water) for pre-wetting treatment (temperature 30 °C, time 30 min); the carrier after pre-wetting treatment was drained, and then subjected to first drying (using a stepwise temperature-raising drying method, drying at 35 °C for 0.5 h, 45 °C for 1.5 h, and 55 °C for 0.5 h in sequence) to obtain the pre-wetted carrier;

[0065] (2) Dissolve 183.8 g of nickel nitrate in 238 g of water to form a salt solution, and divide this salt solution into a first batch of impregnating solution (accounting for 45% of the total weight of the salt solution) and a second batch of impregnating solution (accounting for 55% of the total weight of the salt solution);

[0066] Immerse the pre-wetted carrier obtained in step (1) in the above-mentioned first batch of impregnating solution (the impregnation temperature is 30 °C and the impregnation time is 37 min), and then add the above-mentioned second batch of impregnating solution to the impregnation system to continue impregnation (the impregnation temperature is 30 °C), and the total impregnation time is 52 min;

[0067] Perform second drying on the impregnated carrier above (using a stepwise temperature-rising drying method, drying at 60 °C for 0.5 h, 80 °C for 0.5 h, and 100 °C for 0.5 h in sequence), and then perform calcination (using a programmed temperature-rising calcination method, calcining at 400 °C for 0.5 h, 500 °C for 0.5 h, and 550 °C for 1.0 h in sequence) to obtain a catalyst (denoted as C4).

[0068] Example 5

[0069] According to the scheme of Example 2, the difference is that in step (1), the composition of the pre-wetting solution is changed (the concentration of ammonium bicarbonate is 0.75 g / L, the concentration of methyl cellulose (molecular weight is 20000 g / mol) is 0.12 g / L, and the solvent is water). Other steps and conditions are the same as those in Example 2. Obtain a catalyst (denoted as C5).

[0070] Example 6

[0071] According to the scheme of Example 2, the difference is that in step (2), the salt solution is divided into a first batch of impregnating solution (accounting for 15% of the total weight of the salt solution) and a second batch of impregnating solution (accounting for 85% of the total weight of the salt solution). Other steps and conditions are the same as those in Example 2. Obtain a catalyst (denoted as C6).

[0072] Example 7

[0073] According to the scheme of Example 2, the difference is that in step (2), the second drying adopts a stepwise temperature-rising drying method, drying at 40 °C for 0.5 h, 70 °C for 0.5 h, and 90 °C for 0.5 h in sequence. Other steps and conditions are the same as those in Example 2. Obtain a catalyst (denoted as C7).

[0074] Example 8

[0075] According to the solution of Example 2, the difference is that in step (2), the calcination is carried out by programmed temperature rise calcination, and it is calcined at 400 °C for 0.5 h, at 500 °C for 0.5 h, and at 600 °C for 1.0 h in sequence. Other steps and conditions are the same as those in Example 2. The catalyst is obtained (denoted as C8).

[0076] Comparative Example 1

[0077] According to the method of Example 2, the difference is that in step (1), the carrier is not pre-wetted, but directly proceeds to step (2). Other steps and conditions are the same as those in Example 2. The catalyst is prepared (denoted as D1).

[0078] Comparative Example 2

[0079] According to the method of Example 2, the difference is that the carrier is not pre-wetted, and the impregnation method is one-time impregnation (the impregnation temperature is 30 °C and the impregnation time is 70 min);

[0080] The impregnated carrier is directly dried (dried at a constant temperature of 100 °C for 1.5 h), and then calcined (calcined at 550 °C for 2.0 h) to obtain the catalyst (denoted as D2).

[0081] Test Example

[0082] Test the loss of the loaded metal during the preparation processes of Test Examples 1-8 and Comparative Examples 1-2. The test method is as follows:

[0083] Take appropriate amounts of the above catalyst samples C1-C8 and D1-D2, grind them into powders of about 150 meshes respectively, put them into an oven at 150-155 °C and dry for 1 h, take them out and dry in a desiccator for 20 min; weigh 0.1-0.15 g of the dried catalyst powder and place it in a 250 mL beaker, first rinse the inner wall of the beaker with a small amount of water, then add 10 mL of sulfuric acid solution, put a glass rod in the beaker, cover it with a watch glass, place it on an electric furnace and heat, stir from time to time, when it just starts to emit white smoke, remove the beaker, cool it, and rinse the watch glass and the inner wall of the beaker with hot water until the volume of the solution in the beaker reaches about 50 mL, filter the solution into a 250 mL volumetric flask, rinse the filter paper with hot water until it is no longer acidic; after the solution in the volumetric flask cools, dilute it to the mark with water and shake well, accurately measure 5 mL of the solution with a pipette and transfer it to a 100 mL beaker, measure the absorbance of the solution, and find out the milligram number of the metal element in the solution from the working curve; calculate the actual metal content in the catalyst sample by using the following formula;

[0084]

[0085] X - the actual metal content in the catalyst sample, wt%;

[0086] S - Milligrams of metal found from the working curve, mg;

[0087] D - Dilution factor of the sample;

[0088] m - Weight of the catalyst sample, g.

[0089] The loss amount of the supported metal during the catalyst preparation process is calculated using the following formula:

[0090] The loss amount of the supported metal during the catalyst preparation process = The theoretical metal content in the catalyst sample (i.e., the theoretical metal content calculated based on the feeding amount) - The measured metal content in the catalyst sample. The results are shown in Table 1.

[0091] Table 1

[0092]

[0093] As can be seen from Table 1, by adopting the method for preparing the supported catalyst of the present invention and adding a pre - wetting process for the carrier, the loss of the supported metal during the catalyst preparation process can be achieved to be less than 3 wt%, among which, in Example 1 and Example 2, the loss of the supported metal can be achieved to be less than 2 wt%. Compared with the conventional preparation method D1, the loss of the supported metal during the catalyst preparation process can be reduced by more than 5 wt%; compared with the conventional preparation method D2, the loss of the supported metal during the catalyst preparation process can be reduced by more than 10 wt%.

[0094] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing a supported catalyst, characterized in that, the method comprises: (1) Pre-wetting the support with a pre-wetting solution, followed by first drying to obtain the pre-wetted support; (2) Immersing the pre-wetted support in a solution containing a metal salt, followed by second drying and calcination in sequence to obtain the supported catalyst; wherein the pre-wetting solution contains an ammonium salt and / or cellulose.

2. The method according to claim 1, wherein, the ammonium salt is selected from at least one of ammonium bicarbonate, ammonium chloride, ammonium sulfate and ammonium nitrate, preferably ammonium bicarbonate and / or ammonium nitrate; and / or, the cellulose is selected from at least one of methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl methyl cellulose, preferably methyl cellulose and / or hydroxypropyl methyl cellulose; and / or, the molecular weight of the cellulose is 5000 - 60000 g / mol.

3. The method according to claim 1 or 2, wherein, in the pre-wetting solution, the concentration of the ammonium salt is 0.6 - 1.25 g / L, preferably 0.8 - 1 g / L; and / or, in the pre-wetting solution, the concentration of the cellulose is 0.1 - 0.5 g / L, preferably 0.15 - 0.3 g / L.

4. The method according to any one of claims 1 - 3, wherein, the conditions of the pre-wetting treatment include: temperature is 20 - 50 °C, time is 25 - 35 min.

5. The method according to any one of claims 1 - 4, wherein, the conditions of the first drying include: temperature is 30 - 65 °C, time is 1.5 - 3 h.

6. The method according to any one of claims 1 - 5, wherein, during the impregnation process, the solution containing the metal salt is fed in sequence in the form of a first batch of impregnation solution and a second batch of impregnation solution; the first batch of impregnation solution accounts for 10 - 50% of the total weight of the solution containing the metal salt, preferably 20 - 40%; the second batch of impregnation solution accounts for 50 - 90% of the total weight of the solution containing the metal salt, preferably 60 - 80%.

7. The method according to claim 6, wherein, the impregnation time of the first batch of impregnation solution is 10 - 40 min, preferably 20 - 30 min; and / or, the total impregnation time is 20 - 60 min, preferably 30 - 50 min.

8. The method according to any one of claims 1 - 7, wherein, the conditions of the second drying include: temperature is 30 - 120 °C, time is 0.5 - 1.5 h; and / or, the conditions of the calcination include: temperature is 400 - 650 °C, time is 1.5 - 3 h.

9. The method according to any one of claims 1 - 8, wherein, the support is selected from at least one of alumina, silica and titanium dioxide, preferably alumina; and / or, the specific surface area of the carrier is 150 - 200 m 2 / g, and the pore volume is 0.3 - 0.7 mL / g.

10. The method according to any one of claims 1 - 9, wherein, the metal salt is selected from at least one of molybdenum salt, nickel salt, cobalt salt, platinum salt and palladium salt, preferably at least one of molybdenum salt, nickel salt and cobalt salt.

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