The invention concerns a process for hydroconversion of a hydrocarbonaceous feedstock comprising: a preparation step of at least one catalyst in one or more preparation reactor upstream from a reaction section, wherein (i) at least one preparation reactor feeds one or more reactor of the reaction section, or (ii) preparation reactors are dedicated for catalysts fed to at least a hydroconversion reactor or at least a hydrotreatment reactor of the reaction section; a separation step of solids contained in the liquid effluents issued from the reaction section, a treatment step of residues issued from separation section, comprising a partial oxidation step wherein said residues are partially oxidized to produce carbon monoxide, hydrogen an a metal containing residue. Such process permits improving of products quality, operation of the separation section, recovering of catalytic metals contained in the feed and supplying hydrogen to the reaction section.