摘要: 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 ℃ 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 on 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.
摘要: To get more insight into the pore structure characterization of nanoporous biomass chars, different probe molecules, models, and calibration steps were used and compared. The coconut shell chars (CSCs) were prepared under a steam atmosphere and characterized using N2, Ar, and CO2 adsorption. The results show that coconut shell chars are suitable for further activation, due to the high carbon content and abundant porosity. Ar adsorption with application of Non-Local Density Functional Theory (NLDFT) model can more accurately characterize the pore structure of CSC. When the calibration step is performed before adsorption measurement, the important results of N2 and Ar adsorption, such as pores size distribution (PSD) and isotherm, are affected by pore blocking, leading to the erroneous understanding of CSC in special applications. Vacuum treatment at 273 K for 1 h after He calibration is enough to remove He, which could reduce effect of pore blocking.