Thermogravimetric characteristics and kinetics analysis of oil cake and torrefied biomass blends

The pyrolysis characteristics and kinetics of the blends produced from the mixture of torrefied camphorwood and caster bean cake (CAS) were determined by thermogravimetric analysis. Kissenger-Akahira-Sunose (KAS) and Coats-Redferm methods were applied for kinetic analysis. The results show that torrefaction can increase the maximum decomposition rate and smooth the pyrolysis reaction at 250-330 °C in the differential thermogravimetry (DTG) curves, and the additive of CAS can reduce the high maximum decomposition rate caused by torrefaction. The kinetic results suggest that the activation energy can be enhanced by torrefaction, while this can be lowered by the additive of CAS. It was found that the activation energy dropped dramatically for CAM torrefied at 300 °C by Coats-Redferm method, whereas KAS method showed the contrary trend. The pre-exponential factors by Coats-Redferm method were decreased by the processes of torrefaction and co-pelletization with CAS. In consideration of heating value and activation energy, 270 °C torrefaction and 30% CAS is conservatively selected as the optimum condition.