A comprehensive study on co-pyrolysis of bituminous coal and pine sawdust using TG: Reactivity, product yield, and kinetic constant

Abstract A sample consisting of woody biomass and bituminous coal was pyrolyzed in a lab-scale furnace in a nitrogen atmosphere with the temperature increasing by different heating rates of 5, 10, and 50 C min^-1 until the furnace wall temperature reached 900 C. Five blending ratios (BRs) of coal-biomass were tested. For each BR, the mass loss of the sample and mole fractions of the gaseous species evolved from the sample were measured using a thermogravimetry (TG) and a real-time gas analyzer (GA). Reactivity, product yield, and activation energy were considered as index parameters to co-pyrolysis. While synergy (the difference between the experimental data and calculated results obtained using an additive model) of the reactivity of co-pyrolysis was observed only at specific temperatures, the TG results showed synergy at temperatures between 450 and 500 C compared to between 450 and 600 C seen with the GA method for all pyrolyzed gases, and especially between 350 and 650 C for H₂. While there was no synergy in the char yield of the co-pyrolysis, the liquid and total gas exhibited synergy for all three BRs. The pre-exponential factors and the activation energies of BRs of 0.25, 0.5, and 0.75 were obtained using a kinetic study of co-pyrolysis.