Process and system for producing light olefins from inferior oils

A system for producing light olefins from inferior oils, comprising a thermal conversion reaction unit, a first separation unit, a second separation unit, a hydro-upgrading unit, a third separation unit and a catalytic cracking unit, wherein:

• the thermal conversion reaction unit is configured to carry out a thermal conversion reaction on an inferior oil feedstock in the presence of hydrogen to obtain a conversion product;
• the first separation unit is configured to separate the conversion product to obtain a first separated product, in which the content of components having a boiling point below 350° C. is not greater than about 5 wt %, preferably less than about 3 wt %, and the content of components having a boiling point between 350° C. and 524° C. is about 20-60 wt %, preferably about 25-55 wt %;
• the second separation unit is configured to separate the first separated product into an upgraded oil and a pitch, and is selected from the group consisting of vacuum distillation unit, solvent extraction unit or a combination thereof;
• the hydro-upgrading unit is configured to carry out hydro-upgrading reaction on the upgraded oil to obtain a hydro-upgraded oil;
• the third separation unit is configured to separate the hydro-upgraded oil to obtain a hydro-upgraded heavy oil;
• and
• the catalytic cracking unit is configured to carry out catalytic cracking reaction on the hydro-upgraded heavy oil to obtain a catalytic cracking product comprising a light olefin.