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 (C-2-C-4) 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.

Automated summary

This study investigated the catalytic dehydrogenation cracking of CTO using Py-GC/MS and a fluidized bed reactor, and analyzed the cracking characteristics, kinetics, and product release rules using TG-FTIR. The results showed that the bifunctional catalyst 1Ca/ZSM-5 significantly increased the production of light olefins by adjusting the basicity/acidity.