PRODUCTION OF FUEL OIL BASE MATERIAL

PROBLEM TO BE SOLVED: To obtain a base material for fuel oil that has a low sulfur content and low dry sludge content and excellent storage stability by hydrogenating petroleum distillation residue at three stages under specific conditions. SOLUTION: This fuel oil base material is obtained by hydrogenation at three stages, namely, the first stage that hydrogenates a petroleum distillation residue which is used as a raw fuel oil material and contains 0-5wt.% of dry sludge, 0-500ppm toluene insoluble matter and 1-10% of sulfur, through a hydrogenation catalyst bed maintained at 390-450 deg.C, the second stage that processes the oil which has been hydrogenated at the first stage and has higher contents of dry sludge and toluene-insoluble matter than those of the raw fuel oil material, and sulfur content of not more than 30% of the raw fuel oil material through a hydrogenation catalyst bed which is maintained at 300-400 deg.C and the maximum temperature of which is at least 10 deg.C lower than that in the first stage to obtain processed oil which contains toluene-insoluble matter not more than 50% of that at the outlet of the first stage, and the third stage of hydrogenation at 150-300 deg.C which produces fuel oil having dry-sludge content of 0.1wt.% or less and content of toluene-insoluble matter of not more than 50% of that of the oil at the outlet of the first stage and sulfur content of 30% or less.