Abstract: The invention relates to a process of catalytic hydrovisbreaking of a hydrocarbon charge comprising the following stages:a) Mixing the charge to be treated with a gas containing hydrogen in an amount sufficient for carrying out the hydrovisbreaking reaction,b) introducing into the hydrogen-hydrocarbon charge mixture an amount of a catalytic composition that is sufficient for obtaining a content of metals in the charge to be treated ranging from about 10 to 2,000 ppm by weight in relation to the weight of the charge, said catalytic composition being obtained with a method comprising the following stages:1) subjecting to a thermal treatment under the globally reducing atmosphere of a gas containing hydrogen, the mixture obtained by contacting, in any order, at least one compound other than a sulfide of at least one metal with a hydrocarbon charge containing asphaltenes and with at least one organic polysulfide2) heating the product resulting from statge (b) in the presence of a gas containing hydrogen, andc) su

Abstract: The invention relates to a process for catalytic treatment of heavy hydrocarbons, in a fixed or moving bed, over a catalyst containing an alumina carrier and at least one catalytic metal or compound of metal from groups VB, VI B and VIII of the periodic classification of elements, characterized by the direct injection into the charge, continuously or periodically, of at least one metal compound selected from the group consisting of halides, oxyhalides, oxides, polyacids and polyacid salts of metals from groups VI B, VII B and VIII, before introducing the charge into the hydrotreatment zone.

Abstract: Supported catalysts which are made by shaping catalyst carrier, with or without catalyst precursors, into balls, calcining the balls at 300.degree.-1000.degree. C., and crushing the calcined balls to particles whose average size is 0.2-0.8 times the average diameter of the balls. When the precursors are not present during the manufacture, they are added thereafter.

Abstract: Alumina, silica or silica-alumina containing catalysts are manufactured by incorporating at least one active element selected from the metals of the groups V, VI and VIII or their compounds to a carrier, and then drying and activating. The carrier or the catalyst is shaped into extrudates and the latter are crushed to coarse particles.

Abstract: Supported catalysts for use in hydrocarbons hydrotreatments are made by shaping catalyst carrier, with or without catalyst precursors, into balls, calcining the balls at 300.degree.-1000.degree. C., and crushing the calcined balls to particles whose average size is 0.2-0.8 times the average diameter of the balls. When the precursors are not present during the manufacture, they are added thereafter.

Abstract: A process for the hydrotreatment of a heavy hydrocarbon fraction containing sulfur and metal impurities comprises at least two steps: a first step using a catalyst comprising a low proportion of at least one metal of groups V, VI and VIII, said catalyst being in the form of a plurality of juxtaposed agglomerates each formed of a plurality of acicular plates, the plates of each agglomerate being generally oriented radially with respect to one another and with respect to the center of the agglomerate, the carrier of this catalyst being preferably inert; and a second step using a catalyst which could be of the same type but with a higher proportion of metals. This process is useful for the conversion of crude oils, straight run hydrocarbon residues, deasphalted oils, asphalts dissolved in aromatic distillates and coal hydrogenates.