Coupling process method and coupling process system for improving yield of low-carbon olefins

The invention discloses a coupling process method and a coupling process system for improving the yield of low-carbon olefins. Circulating materials in the process of preparing olefin through light oil fluidized catalytic cracking enter a fixed bed catalytic cracking reactor to serve as raw materials, after fixed bed catalytic cracking reaction discharging materials are separated, C3 and lighter components enter a main separation system of the device, and C4 and heavier components enter the light oil fluidized bed catalytic cracking reactor. Ethane and propane separated by the main separation system of the device enter the steam cracking furnace for cyclic cracking. Through effective coupling of fluidized bed catalytic cracking, fixed bed catalytic cracking and steam cracking, the total yield of ethylene and propylene is improved, the size of a fluidized bed catalytic cracking reactor is reduced, and coking of a fluidized bed catalytic cracking reactor system is delayed. 本发明公开了一种提高低碳烯烃收率的耦合工艺方法和耦合工艺系统。本发明利用轻油