Thermogravimetric study on the flue-cured tobacco leaf pyrolysis and combustion using a distributed activation energy model

In this work, the pyrolysis and combustion characteristics of TLs were tested by using a nonisothermal thermogravimetric analysis, and the distribute activation energy model was used to determine the kinetic parameters. Tobacco leaves from upper, middle, and lower parts of tobacco plants were compared, and the effects of oxygen concentration and heating rate were also investigated. Results show that the decomposition and burnout performances of middle TLs were the best. When oxygen concentration is in the range of 0 to 10%, the increase of oxygen concentration brought little effect on volatile release while remarkably improving residual char burning. The mass loss curves moved backward with the increase of heating rate due to the delay of heat transfer. In general, E first increased and then decreased as mass loss, and it was also affected by oxygen concentration. Energy value under the condition of 10% oxygen concentration is much higher than that under 0% and 5% oxygen conditions. A kinetic compensation effect between E and k was investigated for small molecule species release and char oxidation in TL combustion. The general compensation effects of small molecule species release and char oxidation could be expressed as ln(k) = 0.230E - 4.73 and ln(k) = 0.215E - 17.69, respectively. Copyright (C) 2016 Curtin University of Technology and John Wiley & Sons, Ltd.