Preparation of Ce-Mn/Fe2O3 Catalysts for Steam Catalytic Cracking of Coal Tar

Steam catalytic cracking is an alternative method to produce light tar fractions from coal tar. In this study, Mn-Ce modified Fe2O3 catalysts were prepared by impregnation method, and used for steam catalytic cracking of coal tar in a fixed-bed reactor at 550 degrees C and atmospheric pressure. The results showed that the catalyst Fe80Mn15Ce5 (Fe/Mn/Ce mole ratio 80/15/5) exhibits the best performance in terms of highest light tar yield being 67.6 wt.%. Moreover, the decrease of weight hourly space velocity (WHSV) can further increase the pitch conversion and the light tar content. As a result, when the WHSV is 0.65 h(-1), the light tar yield reaches 71.6 wt.% on Fe80Mn15Ce5. The structural variations of catalysts were characterized by several analytical techniques to reveal the improved catalytic performance. It is shown that the impregnation of MnOx improves the structural stability of Fe2O3 due to the formation of Fe-Mn solid solution, while the load of CeOx activates lattice oxygen. As a result, more active oxygen species generating from steam dissociation can participate in the catalytic upgrading of coal tar.