Investigation of agricultural residues pyrolysis behavior under inert and oxidative conditions

Three samples of biomass including rice straw, corn straw and corncob were analyzed by using TG–MS analyzer. The relevance of the oxidizing versus inert atmosphere to the conversion of Chinese typical agricultural residues are discussed and analyzed. Firstly the effect of oxygen concentration on three biomass conversion pathway is discussed. Secondly the releasing temperature and quantities of major non-condensable gases and tar components are analyzed, and finally the kinetic parameters is calculated and compared.The results show that the oxygen concentration and fuel type play an important role in biomass conversion pathway. All the detected non-condensable gases are favored by oxidative conditions for three samples. With the increase of oxygen concentration, all the condensable gases except H₂ are released over narrower temperature ranges under oxidizing conditions. All the tar components mainly evolve within 300–700 °C, with the increase of oxygen concentration, these major tar components show different features: except that benzene and phenol quickly decreases, other tar components basically changes moderately. The Coats and Redfern integral method is used for kinetic modeling, and Malek method is adopted to select the proper mechanism function. Most of experimental data can be simulated by F1 mechanism model. For the first temperature range of all samples, the values of the activation energy and of the reaction order are lower compared to the case of inert pyrolysis.