Co-pyrolysis of pinewood biomass and bituminous coal with comprehensive analysis of synergistic effects in fuel gas production

• Co-pyrolysis of Pinewood biomass and coal investigated in a MFBRA. • Gas yields (H 2 , CO, CO 2 , CH 4 , C 2 H 4 , and C 2 H 6 ) analyzed at 800 – 1000 °C under argon. • Blended samples showed higher gas yields than individual fuels. • PWB-CB blends (1:1, 3:1) exhibited strong synergistic effects. • Lower activation energy observed in biomass-rich blends. This study investigates the co-pyrolysis behavior of pinewood biomass (PWB) and bituminous coal (CB) in a micro-fluidized bed reaction analyzer (MFBRA) under an argon environment at 800 – 1000 °C to enhance the efficiency of fuel gas production. Gas yields (H 2 , CO, CO 2 , CH 4 , C 2 H 4 , and C 2 H 6 ) were analyzed by gas chromatography (GC) along with their reaction rates. The reaction kinetics were studied through the Volume reaction model (VRM) and kinetic parameters; activation energy(E a ) and pre-exponential factor (A) were evaluated using the Arrhenius model during the process. For PWB, the maximum gas yield was observed at 1000 °C for H 2 and for CO it was observed at 850 °C, while the maximum gas yield of H 2 and CO for CB was observed at 1000 °C. For all the PWB-CB blends, the maximum gas yield of H 2 and the maximum gas yield of CO for PWB-CB (1:1) and PWB-CB (1:3) were observed at 1000 °C, while for PWB-CB (3:1), it was observed at 850 °C. Co-pyrolysis significantly reduced E a and A with the lowest value of (8.15 kJ/mol and 0.31 s −1 ) observed for the PWB-CB (1:1) blend compared to (22.44 kJ/mol and 0.77 s −1 ) and (15.18 kJ/mol and 1.39 s −1 ) for pure CB and PWB which revealed significant synergetic effects. Synergistic effect existence in the PWB-CB blends showed that interactions between biomass volatiles and coal-derived radicals enhanced devolatilization and gas evolution during co-pyrolysis. The PWB-CB (3:1) and PWB-CB (1:1) blends were optimal blends that demonstrated improved gas yields and lower energy barriers based on their individual and overall E a implying better thermochemical performance. This study provides a solid basis for optimizing blend ratios and operating conditions in thermochemical conversion systems.