Thermal Analysis and Kinetic of Three Different Lignocellulosic Biomass

Thermal analysis-experiments of three different biomass species bare,samples, pine wood cotton stalk end fir wood, and the corresponding samples treated with 10%(w/w) sodium carbonate, were conducted at various heating rates under nitrogen atmosphere. The results of the experiments showed that both inner minerals in the biomass and sodium carbonate added into the biomass samples played a catalytic role; which made the pyrolysis occur at lower temperatures. Activation energy values calculated with Popescu method increase along with conversion increasing and this might be due to different pyrolysis characteristics of the components such as hemicellulose and cellulose in the biomass. The best mechanism functions for pyrolysis at low and high temperature scopes were determined by combination of universal integration method and Popescu method. Avrami-Erofeev equation and Zhuralev, Lesokin and Tempelmen (Z-L-T) equation were found to be fit for describing the pyrolysis in different temperature scopes. This indicated the pyrolysis was either three-dimensional random nucleation and nuclei growth or three dimensional diffusion mechanism. Activation energy values calculated by universal integration method were in agreement with those by Popescu method except for those calculated for catalytic pyrolysis at high temperature scopes.