Kinetic analyses of biomass tar pyrolysis using the distributed activation energy model by TG/DTA technique

Abstract

Biomass tar pyrolysis behavior was investigated in absence and presence of catalyst-dolomite (10% mass) with different heating rates of 10, 20, 30 K min−1 under nitrogen atmosphere. Different kinetic methods such as distributed activation energy model (DAEM), Coats–Redfern method were used to analyze the TG/DTA data to identify reaction parameters. For Coats–Redfern method, first reaction order (n = 1) and two stages (volatilization and pyrolysis) reaction model was selected to calculate the kinetics parameters; for DAEM model, three different heating rates (10, 20, 30 K min−1) were selected to obtain the activation energy distribution (Ea). The peak values of Ea curves for biomass tar volatilization process are nearly 250 and 200 kJ mol−1 in absence and presence of dolomite, whereas, the value of Ea for pyrolysis stage gradually increase and varied from 70 to 200 and 40 to 100 kJ mol−1 with the mass loss, respectively, in absence and presence of dolomite. The application of the new DAEM model can show the variation trend of activation energy for the whole pyrolysis process.