Thermochemical behavior and kinetic analysis during co-pyrolysis of starch biomass model compound and lignite

Co-pyrolysis of biomass and coal has been widely investigated as a promising method to reduce the emission of greenhouse gas. Evaluation on thermochemical behavior and kinetics of the co-pyrolysis process is vital for forecasting reaction performance and optimizing this technology. In this study, the thermochemical behavior of a starch biomass model compound (potato starch), a lignite and their blends during pyrolysis were investigated applying a non-isothermal thermogravimetric analyzer. Furthermore, the iso-conversion method was applied to calculate the activation energy. The results of thermogravimetric experiments indicated that the co-pyrolysis characteristics of the blends cannot be accurately predicted on the basis of pyrolysis characteristics of individual components and their blending ratio. The comparison of experimental and theoretical weight loss curves of the blends revealed that a certain degree of synergistic effect happened in the intermediate stage during co-pyrolysis process, but the volatiles yields in the entire co-pyrolysis process were not obviously impacted. Kinetic analysis indicated that the activation energy values of both individual and blended samples varied with the conversion fractions during pyrolysis process. The mean activation energy values of the blends were basically the same as the estimated values calculated by weighted average.