Torrefaction assessment and kinetics of deoiled karanja seed cake

This study demonstrated the efficiency of torrefaction process in upgrading the efficiency of lignocellulosic bioresource, deoiled Karanja seed cake. Torrefaction was carried out at different temperatures within the residence time ranging from 10 to 90min. Elemental analysis clearly shows that there is a significant reduction in H/C and O/C ratio. The mass loss was found to be higher than that of carbon loss which eventually leads to the energy densification. For an average weight loss of 30-35%, the HHV was found in the range of 19.5-21.5 MJ/kg and the total energy that remained in the fuel was around 80-85%. Torrefaction kinetics of karanja deoiled cake was followed to study the thermochemical decomposition and global one step reaction mechanism gave the best representation of the data. The kinetic model proposed provides the recommendations for industrial torrefaction process conditions, remarkably the operating temperature and residence time. The activation energies and pre-exponential factors for thermal degradation, charification, and volatilization were calculated to be 10.55, 30.39, and 3.16 kJ/mol and 0.341, 8.728, and 0.446 min(-1), respectively. (c) 2017 American Institute of Chemical Engineers Environ Prog, 36: 758-765, 2017