High surface area composition for use in the catalytic hydroconversion of a heavy hydrocarbon feedstock, a method making such composition and its use

A catalyst composition, comprising:

• a molybdenum component in an amount of greater than or equal to 5 wt. % and less than 11 wt. %, with the wt. % being based on the total weight of said catalyst composition and assuming said molybdenum component is in the oxide form (MoO3) regardless of its actual form, and a nickel component present in an amount such that said catalyst composition has a weight ratio of said nickel component-to-said molybdenum component exceeding 0.25, with said weight ratio being computed assuming said nickel component and said molybdenum component are each in the oxide form regardless of their actual forms, and wherein said catalyst composition has a total surface area in the range of from 240 m2/g to 360 m2/g, a total pore volume in the range of from 0.65 cc/g to 1.1 cc/g and a pore size distribution such that from 11% to 30.5% of the total pore volume is present in macropores of diameter greater than or equal to 250 Å, a pore size distribution such that from 50% to 80% of the total pore volume of said catalyst composition is present as pores having diameters in the range of from 55 Å to 115 Å, and from 16% to 30% of the total pore volume of said catalyst composition is present in macropores of diameter greater than 500 Å, wherein more than 20% of the total pore volume of said catalyst composition is present in pores of diameter in the range of from 50 Å to 100 Å, and less than 30% of the total pore volume of said catalyst composition is present in pores of diameter in the range of from 100 Å to 200 Å, wherein the pore structure of the catalyst composition is such that from 19.5% to 37% of its total pore volume of the catalyst is present as pores having diameters of greater than or equal to 160 Å, wherein the catalyst composition is prepared by mixing alumina powder, a nickel compound, and a molybdenum compound to provide a co-mulled mixture, comprising said nickel compound, said molybdenum compound and alumina;
• forming an agglomerate of said co-mulled mixture;
• and calcining said agglomerate in air without added steam under calcination conditions to thereby provide said catalyst composition, wherein said mixing step further includes mixing calcined catalyst fines with said alumina powder, said nickel compound, and said molybdenum compound to thereby form said co-mulled mixture, wherein said co-mulled mixture includes an amount of said calcined catalyst fines so as to provide for a desired macroporosity of said catalyst composition.