To remove a coloring substance in the gas oil by bringing the gas oil fraction that is colored with a specific amount of sulfur constituents into contact with a specific alumina or an alumina-containing inorganic oxide.
Colored gas oil fraction (for example, the straight-run gas oil, the catalytically cracked gas oil, thermally cracked gas oil, vacuum distillation gas oil or the like) that are colored by catalytic hydrodesulfurization down to less than 0.05 (mass)% is treated with an alumina with an average pore size of 30-200 (for example γ-alumina or the like), preferably with an inorganic oxide containing 5-98 wt.% of alumina content (for example, boria-alumina), in a preferred embodiment, at 0-400°C, a liquid space velocity of 0-20 hr-1 and the hydrogen pressure of 0.1-4.9 Mpa.
KANBE HIDEKI
MIZUGUCHI HIROSHI
OKI KATSUMI
IDEI KAZUO
COSMO OIL CO LTD