Pyrolysis reaction mechanism of typical Chinese agriculture and forest waste pellets at high heating rates based on the photo-thermal TGA

Abstract

To investigate gas generation characteristics and the kinetics mechanism of biomass pyrolysis process at fast heating rates, a concentrated Photo-thermal TGA reactor (Pt-TGA) was set up. The reactor was reliable for the study of thermochemical kinetics because the average difference between the commercial TGA and Pt-TGA curves for the cellulose pyrolysis process was only 2.1%. Four kinds of typical Chinese forest and agriculture wastes were selected to study the pyrolysis process in Pt-TGA. At higher heating rates, the volatiles from pyrolysis eventually formed more non-condensable gases because of inner-particle secondary reactions. In the range of 450–850 °C, with the temperature rising, the production of H2 increased, and the highest H2 yield reached 279 mL/g. Combined with kinetic analysis, with the increase of heating rate, heat and mass transfer had a more prominent effect on the pyrolysis of biomass particles, and the reactions were controlled by three-dimensional diffusion model.