E309 THE TRANSITION OF THE ACTIVATION ENERGY OF SEMI-CHAR DURING OXIDATION

The activation energy of semi-char in air was investigated using TG Analyzer. The distributed activation energy model (DAEM) was used to study the transition of the activation energy of the semi-char in chemical reaction controlling regime. Initially the activation energy of DT char increases quickly and then rises slowly to a peak point and finally decreases. The activation energies of SM, YX and TW chars firstly experience a comparatively small peak. With the development of oxidation, the activation energy of the SM char keeps very low and at the final stage increases quickly to a peak point and then decrease. The activation energy of YX char increases slowly to a peak point and afterwards decreases. Similarly, the activation energy of TW char increases very slightly and finally increases quickly. In the whole process, the activation energy of JJ char decreases. With the oxidation of semi-char, the active sites are consumed and generated and the pore structure is developed. The difference between the activation energies of the semi-chars is determined by their characteristics. Compared with the coal-chars, the structure of the semi-char derived from the petroleum coke is more uniform. In our future work, we hope to obtain the relationship between the transitions of the reactivity of char and its characteristics using DAEM.