Extracting Kinetic Parameters from TGA Datasets - Ensuring Optimal Outcomes for Cellulose Pyrolysis

Thermal gravimetric analysis (TGA) has been used for decades to study the thermal decomposition of whole biomass and its separated component phases, cellulose, hemicellulose and lignin. Extraction of kinetic parameters from TGA datasets, however, has resulted in a wide range of activation energies and associated pre-exponential factors. A proposed global optimization strategy that incorporates a Nelder-Mead simplex algorithm was used to find optimized kinetic parameters for the thermal decomposition of crystalline cellulose. Visualization of the objective function topology illustrates the difficulty in locating the global optima. A number of plotting strategies are also illustrated as useful tools for the collective comparison of fit outcomes. A systematic study of the effects of search strategy, objective function choice and sample temperature uncertainty was shown to unify the historical findings.