The mechanism of the carbon gasification has been explored in this paper. The dependence of the activation energy on the level of conversion is most likely due to the changes in the gasification control mechanisms. The effect of chemisorption becomes more pronounced at low carbon conversion levels. However, with high levels of conversion, when the values of the activation energy obtained from the DSC data are found to be in good agreement with the values calculated by the TG data, the effect of chemisorption can be neglected. Therefore, the relationship of activation energies could validity determine when chemisorption is negligible. Additionally, the result indicates that the endothermic stage of carbon gasification process can be divided into gasification with chemisorption stage and chemisorption neglected stage. (C) 2011 Elsevier B.V. All rights reserved.