Patent ID: 7361266

Claim:
A refining method for oil in which a feed oil is subject to a refining process, comprising: a distillation step in which the feed oil is separated into a distillate oil and a bottom oil by distillation; a separation step in which the bottom oil is separated into a bottom light oil and a residue by a method including solvent deasphalting (SDA); and a hydrorefining step in which the distillate oil and the bottom light oil are subjected to hydrorefining in the presence of hydrogen using a hydrogenation process unit provided with first and downstream catalyst layers filled with hydrorefining catalysts; and wherein the hydrorefining step comprises a hydrodemetalizing (HDM) step in which an oil passes through the first catalyst layer having a HDM capacity to undergo mainly a HDM process, and a hydrodesulfurizing (HDS) step in which an oil passes through the downstream catalyst layer having a HDS capacity to undergo mainly a HDS process, in the hydrorefining step, the bottom light oil passes through the first catalyst layer of a hydrogenation process unit to undergo the hydrodemetalizing (HDM) step, the distillate oil obtained by the distillation step is added to the bottom light oil that has passed through the first catalyst to cool the bottom light oil and to produce a mixed oil, and the mixed oil passes through the downstream catalyst layer to be subject to the hydrodesulfurizing (HDS) step.