Patent ID: 7435332

Claim:
A process for cracking hydrocarbon oils, characterized in comprising, under cracking conditions, contacting a hydrocarbon oil with a catalyst that has been contacted with an atmosphere containing a reducing gas, separating cracked products and the catalyst, regenerating the catalyst, contacting the regenerated catalyst with said atmosphere containing a reducing gas, wherein said hydrocarbon oil is a sulfur-containing or sulfur-free hydrocarbon oil, said catalyst is a cracking catalyst containing metal components or a catalyst mixture of a cracking catalyst containing metal components and a cracking catalyst free of a metal component, said metal component is present in a reduction valence state, the ratio of average valence to maximum oxidative valence of said metal is 0-0.7, based on said cracking catalyst containing metal components and calculated by oxide of the metal component present in the maximum oxidative valence state, the content of metal component is 0.1-30 wt %, and said metal component is one or more metals selected from the group consisting of non-aluminum metals of Group (IIIA), metals of Group (IVA), Group (VA), Group (IB), Group (IIB), Group (VB), Group (VIB) and Group (VIIB), non-noble metals of Group (VIII) in the Periodic Table of Elements and rare-earth metals; said catalyst contacted with the atmosphere containing a reducing gas at a temperature of 100 to 900° C. for at least 1 second, the amount of the atmosphere containing a reducing gas being not less than 0.03 cubic meters of the reducing gas per ton of the cracking catalyst containing a metal component per minute, and the catalyst contacted with said atmosphere containing a reducing gas at a pressure of 0.12-0.5 MPa.