Insight into kinetic and Thermodynamic Analysis methods for lignocellulosic biomass pyrolysis

Pyrolysis is particularly attractive because it can convert lignocellulosic biomass into bio-oil, gases and solid charcoal in an efficient and environmentally friendly way. Determining the kinetic and thermodynamic parameters is fundamental to elucidate the reaction mechanisms and optimize biomass pyrolysis processes. The applicability and accuracy of kinetic and thermodynamic methods are systematically studied by analyzing theoretically simulated processes which simulate biomass pyrolysis processes and using statistical analyses. In terms of activation energy calculation, the Friedman method is capable of providing accurate activation energies, whereas the KAS and FWO isoconversional methods lead to some systematic errors in the resultant activation energies. The accuracy of the Kissinger method for estimating the frequency factor is dependent on the variation degree of kinetic parameters with conversion. The conventional method for determining thermodynamic parameters is based on the conversion rate peak temperature, which has no theoretical basis. Therefore, the concept of effective thermodynamic parameters is proposed, which are dependent on conversion and heating rate. And the thermodynamic analysis of the simulated processes is comprehensively investigated. Results revealed that the accuracy of the resulting thermodynamic parameters from the conventional method is dependent on the variation degree of kinetic parameters with conversion. It is expected that this study will provide an analysis framework and methodological guideline for the kinetic and thermodynamic analyses of biomass pyrolysis.