Counteractive catalytic effects of FeNi- versus Fe- and Ni- in plastic pyrolysis for advanced-quality jet fuel production

It is promising to produce jet fuel through catalytic pyrolysis of plastic to alleviate the fossil depletion and environmental pollution. Hence, it is important to improve the catalyst and catalytic parameters for the process. This study evaluated the performance of plastic pyrolysis using catalysts loaded with Fe-, Ni-, and FeNi-. The FeNi/Y (Fe and Ni loaded on Y zeolite) catalyst stood out, delivering a high oil yield rate of 64.0 wt%. The obtained oil was abundant in alkanes (38.21 area%) and monocyclic aromatics (35.40 area%) and low in alkenes (13.12 area%), which were optimal for jet fuel production. Various supports were then screened, including four zeolites (Beta zeolite, Y zeolite, Mordenite zeolite, and Zeolite Socony Mobil-5) and activated carbon, with FeNi/Y demonstrating superior performance in both oil yield and quality. Among different pyrolysis temperatures (450, 500, 550, 600, and 650 °C), 550 °C was found to be the ideal temperature for a maximum oil yield. The stable oil yield rate observed during catalyst regeneration experiments confirmed the potential of FeNi/Y for jet fuel production. The research also revealed a significant contrast in catalytic effects between FeNi- and single Fe- or Ni- catalysts. FeNi- favorably cyclized and hydrogenated alkenes, while Fe- and Ni- mainly decyclized monocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. This difference may be attributed to their hydride ion abstraction capability, a trait absent in FeNi.