The co-pyrolysis of sawdust and bituminous coal using thermogravimetric analysis (TGA) and concentration measurements of the evolved species

A sample consisting of woody biomass and bituminous coal was pyrolyzed in a lab-scale furnace with a nitrogen atmosphere until the furnace wall temperature reached 900°C at 10°C/min. Five blending ratios(BRs) of biomass-coal 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 thermogravimetric analyzer(TGA) and a real time gas analyzer(GA), respectively. In order to evaluate the synergistic effect of the co-pyrolysis of the biomass-coal blend on product yield, the cold gas efficiency(CGE) obtained from experimental data was compared with that obtained using an additive model. The TGA results revealed the action of a synergistic effect at temperatures between 450 and 500°C, compared to between 450 and 600°C with the GA method, for all pyrolyzed gases, and especially between 350 and 650°C for H2. The maximum CGE was 0.37 at the BR of 0.75, while the maximum ratio between the experimental CGE and the calculated CGE was 1.52 at the BR of 0.25. In addition, kinetics analysis of co-pyrolysis was conducted and it was found that the activation energies of BRs at the temperature of 390 to 450°C can be predictable using the additive method.