| abstract |
A process for hydroprocessing heavy oil feedstock is disclosed. The process operates in once-through mode, employing a plurality of contacting zones and at least a separation zone to convert at least a portion of the heavy oil feedstock to lower boiling hydrocarbons, forming upgraded products. The contacting zones operate under hydrocracking conditions, employing a slurry catalyst for upgrading the heavy oil feedstock. At least an additive material selected from inhibitor additives, anti-foam agents, stabilizers, metal scavengers, metal contaminant removers, metal passivators, and sacrificial materials, in an amount of less than 1 wt. % of the heavy oil feedstock, is added to at least one of the contacting zones. In one embodiment, the additive material is an anti-foam agent. In another embodiment, the additive material is a sacrificial material for trapping heavy metals in the heavy oil feed and/or deposited coke, thus prolonging the life of the slurry catalyst. |