Steam catalytic cracking of coal tar over iron‐containing mixed metal oxides

Abstract

AbstractSteam catalytic cracking is deemed as a promising method for the catalytic cracking of coal tar. In this study, a serial of iron‐containing mixed metal oxides including ceria, zirconia, alumina, cobalt, nickel, and barium oxides were prepared for steam catalytic cracking of coal tar and characterized by N2 adsorption‐desorption, X‐ray diffraction, H2 temperature programmed reduction, and Raman spectroscopy, respectively. It was found that the specific surface area and pore volume increase while the crystal size decreases when Fe2O3 was doped with the investigated metal oxides. Among these, iron‐alumina mixed oxide (FeAl) shows the highest specific surface area and pore volume. The H2‐TPR analysis indicated that most of the mixed metal oxides have lower reduction temperature, especially for iron‐ceria mixed oxide (FeCe). The reduction temperature of FeCe is around 500 °C, and its reduction peak shifts to a lower temperature and becomes narrower as compared to other iron‐containing mixed metal oxides. The steam catalytic cracking of coal tar at 550 °C showed that the light tar content (below 360 °C) over FeCe, FeCo, and FeAl are 68.5, 67.0, and 66.5 %, respectively. The increase of CO2 and H2 over iron‐containing mixed metal oxides suggested that oxygen species from iron‐containing mixed metal oxides and steam could participate in the steam catalytic cracking of coal tar.