Effect of catalysts on the reactivity and structure evolution of char in petroleum coke steam gasification

Petroleum coke was gasified using non-isothermal thermogravimetric analysis (TGA). The catalytic effects of FeCl 3 , CaCl 2 , KCl, K 2 CO 3 , K 2 SO 4 , KAC and KNO 3 were studied. It was found that the gasification of petroleum coke was inefficient at temperature 2 CO 3 , gasification was completed quickly in 10 min and the final temperature was about 900 °C. To further uncover the catalytic mechanism, the structures of char samples at various conversions were investigated with Raman spectra (Raman) and X-ray diffractometry (XRD). The Raman spectra showed that with K 2 CO 3 catalyst, the formation of active intermediates C(O) and M–C–O were enhanced by the relatively small aromatic ring systems with 3–5 fused benzene rings, alkyl–aryl C–C structures and methyl carbon dangling onto an aromatic ring. K 2 CO 3 could stimulate the crackdown of big aromatic ring systems into small aromatic ring systems. Thereby, the addition of K 2 CO 3 could increase the steam gasification rate of petroleum coke. XRD analysis indicated that with char conversion increasing, char structure became more ordered with a large amount of aromatic ring formed in original samples, while the degree of graphitization was lowered with K 2 CO 3 addition, which is favorable for char gasification.