Catalytic conversion method for improving productivity of low carbon olefin hydrocarbon

Abstract

A catalytic conversion method for improving the yield of low-carbon olefin comprises the following steps: hydrocarbon oil raw material is injected into a riser or/and a fluidized bed reactor via a feed nozzle, comes into contact with catalyst containing shape-selective zeolite with an average pore size being smaller than 0.7 nm and reacts; gas rich in hydrogen is injected into the reactor; reaction oil gas and carbon deposited catalyst after reaction are separated, wherein the reaction oil gas is separated to obtain a target product containing ethylene and propylene; and the carbon deposited catalyst is returned to the reaction for reutilization after being stripped and regenerated. By injecting gas rich in hydrogen, the method can remarkably inhibit reconversion reaction of the generated low-carbon olefin to improve the yield of low-carbon olefin, particularly of propylene. When vacuum gas oil is adopted as raw material and double risers combined with a fluidized bed reactor are adopted, ethylene yield reaches 8.97 wt%, and propylene yield reaches 31.38 wt%, which are respectively improved by 2.93% and 6.81% in comparison with a process without injection of gas rich in hydrogen.

Description

technical field The invention belongs to a method for catalytic conversion of hydrocarbon oil, more specifically, a method for preparing low-carbon olefins such as ethylene and propylene through catalytic conversion of hydrocarbon oil under the action of a catalyst. Background technique At present, the traditional method of producing low-carbon olefins is the tube furnace steam cracking method, and the suitable raw materials for this method are light petroleum hydrocarbons such as ethane, propane, butane, naphtha or light diesel oil. As crude oil becomes heavier, the supply of light petroleum hydrocarbons is limited, forcing researchers to turn their attention to using a wider range of raw materials including heavy petroleum hydrocarbons to produce light olefins. In recent years, some patent documents have disclosed the method of producing light olefins by using raw materials such as heavy petroleum hydrocarbons, naphtha and C4-C6 light hydrocarbons by catalytic cracking re...

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Problems solved by technology

However, the inventors have found through laboratory research that under the reaction conditions for preparing low-carbon olefins by catalytic conversion of hydrocarbon oils and the presence ...

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