Pyrolysis Characteristics and Kinetics of Coal–Biomass Blends during Co-Pyrolysis

Abstract

In this paper, the chemical structures of coal and three types of biomass were investigated by Fourier transform infrared spectroscopy. To evaluate the effects of the biomass blending ratio, heating rate, and biomass type on the co-pyrolysis behaviors, the pyrolysis behaviors of coal, three types of biomass, and coal–biomass blends were studied through nonisothermal thermogravimetric analysis. The results expose that coal is rich in the aromatic C═C, however the biomass is rich in O–H group and C–O group. For three types of biomass, the type of main functional groups is same, but the relative content of them is different. During the co-pyrolysis processes of coal and biomass, the experimental RB is higher than the calculated values. Conversely, the experimental Rcoal is lower than the calculated values, whereas the experimental Tcoal shifts to lower temperature. Therefore, we can deduce that the interaction occurs during the co-pyrolysis processes of coal and biomass. In addition, whether biomass has synergistic or inhibitory effect in the whole co-pyrolysis process is related to the mixing ratio, the heating rate, and the type of biomass. Finally, the kinetic parameters of coal and sawdust pyrolysis process were obtained by the simplified distributed activation energy model method.