关键词: 催化裂解, 低碳烯烃, 纳米氧化铈, 液化气

Abstract: To explore the application potential of nanoscale cerium oxide (nano-CeO2) in catalytic cracking processes for enhancing light olefin yield, this study conducted experiments on a fixed fluidized-bed reactor, a continuous-feed pilot-scale unit, and a commercial 350 kt/a catalytic cracking unit. Results from the small-scale tests showed that loading nano-CeO2 onto the catalyst increased light olefin yield, with a more pronounced enhancement observed at lower reaction temperatures. An optimal loading range was identified; beyond this range, the promotional effect gradually diminished. Pilot-scale trials demonstrated that, at a theoretical nano-CeO2 loading of 3 760 μg/g on the catalyst, light olefin yield increased by 3.60 percentage points and conversion rose by 1.87 percentage points. Validation on the industrial unit further confirmed the feasibility and effectiveness of this approach. Characterization by pyridine adsorption Fourier-transform infrared spectroscopy (Py-IR) and ammonia temperature-programmed desorption (NH3-TPD) revealed that the incorporation of nano-CeO2 increased both Br?nsted acid site density and the amount of medium-strong acid sites on the catalyst. This promoted carbocation formation and subsequent cracking reactions, thereby enhancing feedstock conversion and light olefin yield.

Key words: deep catalytic cracking, light olefin, nano-ceria, liquefied petroleum gas