Method for preparing catalyst with non-uniform distribution of active metal component

[0024] Example 1

[0025] Weigh 1000g aluminum hydroxide powder (dry rubber powder produced by Changling Refining and Chemical Company Catalyst Plant), and extrude it into a cylindrical bar with a diameter of circumscribed circle of 1.2 mm using an extruder, and dry the wet bar at 120°C for 4 hours, 900°C After calcining for 4 hours, the alumina carrier obtained is denoted as Z1. The water absorption rate was determined to be 1.04 ml/g.

[0026] Weigh 200g of carrier Z1, add the above substances to deionized water in the order of tartaric acid, ammonium paramolybdate, and nickel nitrate. The ratio of the moles of tartaric acid to the sum of the moles of ammonium paramolybdate and nickel nitrate is 0.2. (Containing 25% NiO) is 8.83g, ammonium molybdate (containing MoO 3 82%) is 20.2g, 209ml of deionized water is added, and the mixture is stirred until it is completely dissolved to obtain an immersion solution. After mixing uniformly, measure the pH value of the immersion liquid with a pH meter to be 1.5. The carrier was immersed in the impregnation solution, dried at 80°C for 6 hours after 120 minutes, and finally calcined in air at 500°C for 3 hours to prepare catalyst C1. The specific surface and pore volume of the catalyst were determined by the BET low-temperature nitrogen adsorption method, the content of the hydrogenation active metal components was determined by the XRD fluorescence method, and the hydrogenation active metal components along the radial distribution of the support were measured by SEM-EDX, and calculated from the characterization results The ratio of the concentration of the metal component at the outer surface to the center of the particle (the same below), and the characterization results are shown in Table-1.

[0027] Example 2

[0028]Weigh 1000g aluminum hydroxide powder (dry rubber powder produced by Changling Refining & Chemical Company Catalyst Plant), use an extruder to form a cylindrical bar with a diameter of 1.2 mm circumscribed circle, and dry the wet bar at 120°C for 4 hours, 800°C After calcining for 4 hours, the alumina carrier obtained is denoted as Z2.

[0029] Weigh 200g with a water absorption rate of 1.04ml.g -1 Add the above-mentioned substances to deionized water in the order of citric acid, TW-20, ammonium paramolybdate, and cobalt nitrate. Among them, cobalt nitrate (containing CoO25.8%) is 10.19g, and ammonium molybdate (containing MoO 3 82%) is 22.4g. The ratio of the number of moles of citric acid to the sum of the number of moles of ammonium paramolybdate and cobalt nitrate is 0.65, and the molar ratio of the added surfactant TW-20 to the amount of citric acid is 0.4. Add 210ml of deionized water and stir evenly until completely dissolved. After mixing uniformly, use a pH meter to measure the pH of the immersion liquid to be 3.2. The carrier was immersed in the impregnating solution, placed in a container for homogenization at 35°C for 120 minutes, then dried at 100°C for 4 hours, and finally calcined in the air at 500°C for 3 hours to prepare catalyst C2.

[0030] Example 3

[0031] Weigh 1000g of aluminum hydroxide powder (same as Example 1), use an extruder to form a cylindrical bar with a circumscribed circle diameter of 1.2 mm, dry the wet bar at 120°C for 4 hours, and calcinate at 600°C for 4 hours to prepare alumina The carrier is denoted as Z3.

[0032] Weigh 200g of water absorption rate of 0.96ml.g -1 Γ-Al 2 O 3 As the carrier, add the above substances to deionized water in the order of phosphoric acid, TW-80, ammonium metatungstate and nickel nitrate. Among them, nickel nitrate (containing NiO25%) is 7.23g, and the added ammonium metatungstate contains metatungstic acid. For the 8.5m% ammonium solution, the ratio of the number of moles of phosphoric acid to the sum of the number of moles of ammonium metatungstate and nickel nitrate is 0.8, and the molar ratio of the added surfactant TW-80 to the amount of phosphoric acid is 0.65. Add 204ml of deionized water until it is completely dissolved. After mixing evenly, measure the pH value of the immersion solution with a pH meter to be 3.12. The carrier was immersed in the impregnating solution, dried at 100°C for 4 hours after 60 minutes, and then calcined in air at 500°C for 3 hours to prepare catalyst C3.