Upgrading of coal tar with steam catalytic cracking over Al/Ce and Al/Zr co-doped Fe2O3 catalysts

Abstract

The upgrading of coal tar by means of steam catalytic cracking (SCC) is a promising method. In this study, Al/Ce and Al/Zr co-doped Fe2O3 catalysts were prepared and used for SCC of coal tar for improving the light tar yield. The SCC was conducted at 550°C for 1 h. It was found that the crystal size decreased over doped Fe2O3 catalysts, and the pore volume and specific surface area increased. XPS analysis showed that lattice oxygen was the majority oxygen species and doping can increased the O− concentration. It was shown that Al/Ce and Al/Zr co-doped Fe2O3 could improve the catalytic activity of Fe2O3. The light tar yield over FeAlZr1, FeAlZr2, FeAlCe1 and FeAlCe2 were 63.2%, 58.1%, 60.2% and 55.1%, respectively, higher than that over Fe2O3 being 49.7%. The oxygen species from steam dissociation and Fe2O3 could take part in the upgrading of coal tar. It was revealed that the specific surface area and the O− on the Fe2O3 catalysts were the primary factors in determining the SCC performance.