Abstract: The present invention relates to a catalyst combination for hydrotreating raw oils and a process for hydrotreating raw oils with the catalyst combination. The catalyst combination comprises one or both of at least one hydrogenation protection catalyst I and at least one hydrogenation demetalling catalyst I; at least one hydrogenation demetalling catalyst II; and at least one hydrogenation treatment catalyst III.

Abstract: The present invention relates to a slurry bed loop reactor comprising a riser and at least one downcomer (3), wherein two ends of the riser are connected to two ends of the downcomer (3) via lines (16) and (7), respectively. The riser comprises a reaction section (1) and a settling section (2) with an increased tube diameter disposed on the reaction section (1). A gas outlet (13) exists at the top of the settling section (2). Each of the downcomers (3) is divided into a filtrate section (5) and a slurry section (6) by filter medium (4), wherein the filtrate section (5) is connected to a liquid outlet (10); two ends of the slurry section (6) are respectively connected to two ends of the riser, and the filtrate region (5) may further be connected to a back purging system.