Hydrotreating of petroleum residuum using shaped catalyst particles of small diameter pores

A process for hydrotreating a petroleum residuum with a porous hydrotreating catalyst particle to obtain a desulfurized product, said particle having a composition comprising a major portion of alumina;

• up to about 36 weight percent of silica, based on the total weight of silica and alumina;
• from about 10 to 25 weight percent of molybdenum in the form of its oxide or sulfide;
• and a total of about 1 to 8 weight percent of a metal selected from cobalt, nickel and mixtures thereof in the form of the corresponding oxide or sulfide, said percentages being based on the total weight of said catalyst particle, said particle being further characterized by a trilobal cross-sectional shape defining a concave geometric solid, said trilobal cross-sectional shape being defined by circles, all of said circles in said cross-sectional shape having equal diameters, the centers of said circles being spaced from one another by a distance which is from about three-eighths to fifteen-sixteenths of the diameters of said circles, lines connecting the centers of adjacent circles form a substantially equilateral triangle, each side of said triangle being from three-eighths to fifteen-sixteenths of the diameters of said circles and all of the cross-sectional shape included by said circles being of said composition;
• said particle size being defined by a ratio of geometric volume to geometric surface in the range of about 0.005 to 0.025 inch;
• a catalytic surface area greater than 200 square meters per gram;
• and a catalytic pore volume in the range of about 0.45 to 0.85 cubic centimeters per gram, said catalytic pore volume resulting from a major portion of pores of diameter of about 40 to 90 Angstrom units when measured with mercury at up to about 50,000 pounds per square inch absolute pressure and a contact angle of 140.degree.;
• which process comprises contacting said residuum with said catalyst particle and with hydrogen at a flow rate of about 500 to 5,000 standard cubic feet per barrel of oil at a liquid hourly space velocity of about 0.20 to 5.0 reciprocal hour, at a temperature in the range of about 600.degree. to 850.degree. F., and a total pressure in the range of about 200 to 10,000 pounds per square inch gauge.