Nickel Cobalt Molybdenum Tungsten Hydrodesulfurization Catalyst

At present, hydrofining catalysts are usually prepared by introducing active metal components from solution or suspension into the carrier through impregnation, and then by drying and calcination. Among them, nickel cobalt molybdenum tungsten sulfide is a highly active hydrodesulfurization catalyst. Impregnation is a common method to prepare supported catalysts, but there are some problems such as uneven metal components on the surface of the support, large particles of active components and uneven dispersion.

In view of the problems existing in traditional methods, researchers have created a method for preparing tungsten hydrodesulfurization catalyst with simple and feasible synthesis process, short cycle and low cost. The main contents are as follows:

(1)Nickel salt, cobalt salt, molybdenum salt and tungsten salt were dissolved in deionized water to prepare a clarified solution with molar concentration of 0.2-2.0 mol/L, respectively.

(2)Cobalt-molybdenum or nickel-molybdenum binary precipitates were obtained by adding molybdenum salt solution to cobalt salt solution or nickel salt solution and stirring for 30 minutes. Cobalt-tungsten or nickel-tungsten binary precipitates were obtained by adding tungsten salt solution to cobalt salt solution or nickel salt solution. Cobalt-molybdenum-tungsten or nickel-molybdenum-tungsten ternary precipitates were prepared by continuous stirring in salt solution or nickel-salt solution for 30 minutes. The mixed solution of molybdenum salt and tungsten salt was added to the mixed solution of cobalt salt and nickel salt and stirred continuously for 30 minutes. Nickel-cobalt-molybdenum-tungsten four-component precipitation was prepared,  the precipitation was filtered, washed and dried to obtain oxide precursor powder, or the heat-resistant inorganic oxide carrier was added to the corresponding cobalt salt solution or one of the nickel salt solution or the mixed solution of cobalt salt and nickel salt, stirred for more than 30 minutes, added molybdenum salt solution or molybdenum salt solution. A kind of tungsten salt solution or a mixed solution of molybdenum salt and tungsten salt, the corresponding metal composite oxide precipitation, and then filter, washing, drying, oxide precursor powder.

(3)The oxide precursor and decalin solution containing CS₂ were loaded into a high-pressure magnetic stirred tank, in which the mass of CS₂ was more than three times that of the oxide precursor, the hydrogen pressure of 2.0-5.0 MPa was maintained. The temperature was raised to 200-400°C for 6-24 hours. The reactant was cooled naturally. After the tank was opened, the reactant was removed, centrifuged with cyclohexane for 3 times, then vacuum dried for 0.5-8 times. Within hours, cobalt-molybdenum sulfide, nickel-molybdenum sulfide, cobalt-tungsten sulfide, nickel-tungsten sulfide, cobalt-molybdenum-tungsten sulfide, nickel-molybdenum-tungsten sulfide and nickel-cobalt-molybdenum-tungsten sulfide were obtained.

The outstanding advantages of this process are: the precursor before vulcanization is prepared by coprecipitation method, the sulfide has good dispersion on the carrier, the synthesis process is simple and feasible, the cycle is short, and the cost is low.

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