Integrated process for hydrogenation and catalytic cracking of hydrocarbon oil

An improved combined method of hydrotreating and catalytic cracking of hydrocarbon oil, comprising:

• contacting residual oil, catalytic cracking cycle oil, and optional distillate oil with a hydrotreating catalyst under hydrotreating conditions in the presence of hydrogen followed by separation of the reaction products to obtain gas, hydrogenated naphtha, hydrogenated diesel oil, and hydrogenated tail oil;
• contacting the hydrogenated tail oil and an optional normal catalytic cracking feedstock oil with a catalytic cracking catalyst under catalytic cracking conditions followed by separation of the reaction products to obtain dry gas, liquefied petroleum gas, catalytically cracked gasoline, catalytically cracked diesel oil, and catalytic cracking cycle oil;
• wherein
• the catalytic cracking cycle oil comprises less than 30 wtppm of solid particles, and the size of the solid particles being less than 10 μm;
• the contact reaction with the cracking catalyst is carried out in a reactor having at least two reaction zones I and II along the flow direction of reactants;
• prior to contacting the hydrogenated tail oil and the optional normal catalytic cracking feedstock oil with the cracking catalyst, at least a portion of the hydrogenated tail oil is separated into at least two fractions, the light and the heavy fractions of the hydrogenated tail oil, and the optional normal catalytic cracking feedstock oil is optionally separated into normal catalytic cracking heavy feedstock oil and normal catalytic cracking light feedstock oil, wherein the separated heavy fraction is a hydrocarbon oil with a boiling point above 500° C., and the separated light fraction is a hydrocarbon oil with a distillation range of 350˜500° C.,
• the contact reaction with the cracking catalyst comprises:
• charging the reaction zone I with one of the light fraction and the heavy fraction of the hydrogenated tail oil, and optionally with at least one feed chosen from unseparated hydrogenated tail oil, unseparated normal catalytic cracking feedstock oil, normal catalytic cracking heavy feedstock oil, and normal catalytic cracking light feedstock oil;
• whereas charging the reaction zone II with the other of the light fraction and the heavy fraction of the hydrogenated tail oil, and optionally with at least one feed chosen from unseparated hydrogenated tail oil, unseparated normal catalytic cracking feedstock oil, normal catalytic cracking heavy feedstock oil, and normal catalytic cracking light feedstock oil.