Method for preparing aromatic hydrocarbons through catalytically pyrolyzing waste polyolefin plastics

The invention belongs to the field of resource-converting utilization of waste plastics and particularly relates to a method for preparing aromatic hydrocarbons through catalytically pyrolyzing waste polyolefin plastics. According to the method, liquid aromatic hydrocarbons are synthesized through catalytic rapid pyrolysis in a manner of taking the polyolefin plastics as a raw material, taking niobic acid as a catalyst, taking nitrogen gas as carrier gas and taking a catalytic pyrolyzer as a reactor. Preferably, polypropylene serves as the raw material, 1M/L phosphoric acid equal-volume-impregnated niobic acid serves as the catalyst, and thus, the yield of the aromatic hydrocarbon product is increased. In the product of catalytic pyrolysis of the polyolefin plastics by the niobic acid, the yield of the liquid aromatic hydrocarbons is high, subsequent separation and extraction are facilitated, and the catalyst can be reused repeatedly. The production process is simple in process and facilitates continuous prod