Demetalation and desulfurization of residual oil utilizing hydrogen and trickle beds of catalysts in three zones

A method for demetalizing and desulfurizing a residual oil which comprises passing a mixture of hydrogen and said oil at a hydrogen pressure of 500 to 3000 psig, a temperature of about 600 .degree.to 850.degree. F, and a space velocity of 0.1 to 5.0 LHSV, through trickle beds of catalysts disposed in three sequential reaction zones, the first zone containing a relatively larger bed of a said first catalyst, the third zone containing a relatively smaller bed of said first catalyst, and the second zone located between said first zone and said third zone containing a second catalyst, said first catalyst and said second catalyst comprising the oxides or sulfides of a Group VIB metal and an iron group metal on an alumina support, said first catalyst having at least 60 percent of its pore volume in pores with diameters of about 100 to 200A and at least about 5 percent of its pore volume in pores greater than 500A diameter, and said second catalyst having a surface area of at least 150 m.sup.2 /g and at least 50 percent of its pore volume in pores with diameters of 30 to 100A.