Reforming of waste PET pyrolysis products into fuel-range hydrocarbons using Ni-doped CaO catalyst

Catalytic pyrolysis offers a promising solution in converting waste plastics including PET into fuels and other useful petrochemicals. In this study, nickel-doped calcium oxide (Ni-CaO) catalysts with Ni loadings of 3 wt% and 5 wt% were synthesized and used in a two-step waste PET pyrolysis and catalytic reforming process. PET was pyrolyzed at 500 ° C, and the resulting vapour was catalytically reformed at 600 ° C in a fixed bed reactor. Reformed products were separated into two categories, non-condensable and condensable gases and analysed using an online gas analyzer and FTIR and Gas Chromatography (GC) respectively. Product distribution indicated that catalytic upgrading suppressed heavy hydrocarbon formation when compared with the non-catalysed reaction (lubricating oil from 13.5% to ≤ 3.2%). CaO favoured gasoline (43.8%), while 5 wt% Ni–CaO promoted kerosene (38.7%), demonstrating compositionally tuneable products. Gas analysis revealed that hydrogen and methane production was highest in the presence of 5 wt% Ni-CaO, indicating enhanced reforming activity at this Ni loading. Catalyst characterization by X-ray fluorescence (XRF), FTIR, X-ray diffraction (XRD), and scanning electron microscopy (SEM) confirmed the successful incorporation of Ni into the CaO matrix without significant alteration in the CaO crystalline structure. The research highlights the effectiveness of Ni-CaO catalysts in the two-step reforming of PET to fuel-range hydrocarbons.