Catalytic conversion method of increasing the yield of lower olefin

Abstract

A catalytic conversion process for increasing the light olefin yields, which comprises bringing a hydrocarbon oil feedstock into contact with a catalytic conversion catalyst in a catalytic conversion reactor including one or more reaction zones to carry out the reaction, wherein the hydrocarbon oil feedstock is subjected to the catalytic conversion reaction in the presence of an inhibitor; and separating the reactant vapor optionally containing the inhibitor from the coke deposited catalyst, wherein a target product containing ethylene and propylene is obtained by separating the reactant vapor, and the coke deposited catalyst is stripped and regenerated for recycle use by being returned to the reactor. The process can weaken the further converting reaction of produced light olefins such as ethylene and propylene to 50-70% of the original level by injecting the inhibitor; thereby it can increase the yields of the target products. When vacuum gas oil is used as the feedstock, the yield of ethylene is as high as 8.73 wt % and that of propylene is as high as 29.30 wt %, increasing by 14.4% and 26.6% respectively comparing to those obtained without the inhibitor being injected.