Method for the sulphidation of hydrotreating catalysts
The invention concerns a method for sulphurizing catalysts for hydrotreating of hydrocarbon feedstocks. The invention is characterised in that it consists in sulphurizing the catalyst in two steps: the first step consisting in sulphurization with tertiary mercaptan in the absence of hydrogen, and the second step, carried out consecutively in the same reactor, consisting of sulphurization with another sulphurizing agent in the presence of hydrogen. The catalysts thus sulphurized prove to be more active than those sulphurized by only the second step.
1 . Process for the in situ sulphidation of a metal hydrotreating catalyst comprising a first stage of treatment of the catalyst with a tertiary mercaptan in the absence of hydrogen, followed, in the same reactor, by a second stage of treatment with another sulphidation agent in the presence of hydrogen.
2 . Process according to claim 1 , in which the metal catalyst to be sulphided comprises a mixture of cobalt and molybdenum oxides, a mixture of nickel and molybdenum oxides or a mixture of nickel and tungsten oxides or any other combination of these oxides.
3 . Process according to claim 1 , in which the tertiary mercaptan is tert-dodecyl mercaptan.
4 . Process according to claim 1 , in which the other sulphidation agent is dimethyl disulphide.
5 . Process according to claim 1 , in which the first stage comprises an impregnation of the catalyst with the tertiary mercaptan and then a thermal activation under an inert atmosphere.
6 . Process according to claim 5 , in which the thermal activation is carried out at a temperature of between 100 and 175° C.
7 . Process according to claim 1 , in which the second stage is carried out in two steps, first at a temperature of between 150 and 250° C., until breakthrough of H 2 S into the outlet gases is obtained, and then at a temperature of between 250 and 350° C., until a constant concentration of H 2 S in the outlet gases is obtained.
8 . Process according to claim 1 , in which the total amount of sulphur contributed by the tertiary mercaptan and the other sulphidation agent ranges from 100 to 250% of the weight of sulphur stoichimetrically required for complete conversion to sulphides of the oxides of the catalyst.
9 . Process according to claim 8 , in which the proportion of tertiary mercaptan corresponds to more than 10% by weight of the total sulphur necessary for the sulphidation of the catalyst.
10 . Process according to claim 2 , wherein said mixture of oxides being supported by an alumina, a silica or a silica/alumina.
11 . Process for hydrotreating hydrocarbonaceous feedstocks comprising contacting said hydrocarbonaceous feedstocks with a metal hydrotreating catalyst, wherein said catalyst has undergone in situ sulphidation comprising a first stage of treatment of the catalyst with a tertiary mercaptan in the absence of hydrogen, followed, in the same reactor, by a second stage of treatment with another sulphidation agent in the presence of hydrogen according to claim 1 , in which the total amount of sulphur contributed by the tertiary mercaptan and the other sulphidation agent ranges from 100 to 250% of the weight of sulphur stoichiometrically required for the complete conversion to sulphides of the