Catalytic dehydrogenation cracking of crude oil to light olefins by structure and basicity/acidity adjustment of bifunctional metal/acid catalysts

Catalytic dehydrogenation cracking of crude oil to light olefins (CTO) was carried out by pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) and a fluidized bed reactor. Cracking characteristics, apparent kinetics, and product release rules of CTO were analyzed by the thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TG-FTIR). Results showed that dehydrogenation-cracking bifunctional catalysts could be obtained only when the properties of metals matched with acid catalysts. The bifunctional 1%Ca/ZSM-5 (1Ca/ZSM-5) catalysts can increase dehydrogenation, attenuate hydrogen transfer, and inhibit coking. Consequently, light (C2-C4) olefins produced from 1Ca/ZSM-5 catalyst were enhanced significantly. There were mainly-two stages of pyrolysis and catalytic dehydrogenation cracking in the catalytic conversion of crude oil. The activation energy of bifunctional 1Ca/ZSM-5 catalyst decreased in the pyrolysis stage. The product adjustment mechanism by bifunctional catalysts was proposed from the perspective of structure and basicity/acidity, which would guide the maximization production of light olefins.