The kinetics model and pyrolysis behavior of the aqueous fraction of bio-oil

The pyrolysis behavior and kinetics of the aqueous fraction of bio-oil were studied through thermogravimetric (TG) analysis. Based on the experimental data, activation energies and kinetic parameters were calculated by the Achar differential method and the Coats-Redfern integral method, then the most probable mechanism functions and kinetics model were obtained at last. The results show that the pyrolysis of bio-oil aqueous fraction can be divided into three stages, that is, the volatilization of volatile fractions, the decomposition stage of heavy fractions and char combustion. The experimental results show that the activation energy of volatilization is higher than that of the decomposition stage. The first stage was expressed as the first order reaction and the second stage the second order reaction. The correlation coefficient between the two stages illustrates that the reactions are in well conformity with each other and the calculated value of conversion is consistent with the experimental results. (C) 2012 Elsevier Ltd. All rights reserved.