TG-FTIR analysis of co-pyrolysis behavior between petroleum coke and model lignocellulosic biomass

The co-pyrolysis of petroleum coke with lignocellulosic biomass components offers a promising route for the high-value utilization of petroleum-refining by-products and sustainable biomass conversion. This study employs coupled Thermogravimetric analysis-Fourier-transform infrared spectroscopy (TGA-FTIR) to systematically examine the co-pyrolysis behaviour and interaction mechanisms between petroleum coke and model lignocellulosic components (cellulose, hemicellulose and lignin) across the temperature range 30–850 °C at heating rates of 5, 10, 15 and 20 °C·min −1 . The results demonstrate that the cellulose–petroleum coke system exhibits optimal volatile-release kinetics at 10 °C·min −1 , with a diffusion coefficient (D = 9.65 × 10 −10  min −2  °C −3 ) and a maximum mass-loss rate (DTG max  = −1.47 %·min −1 ). In contrast, the lignin–petroleum coke system shows pronounced synergistic effects at high temperatures (>600 °C), as supported by activation energies of 57.60–84.14 kJ mol −1 and Gibbs free-energy changes (ΔG = 72.23–98.01 kJ mol −1 ), indicating catalytic and flame-retardant potential. Mechanistic insights reveal that lignocellulosic components exert phase-dependent modulation on pyrolysis dynamics, suppressing petroleum-coke hydration, fine-tuning volatile-diffusion kinetics and facilitating graphitization via co-carbonization pathways. These findings provide a scientific basis for the precise engineering of pyrolysis-product characteristics and advance the development of tailored thermochemical conversion strategies.