Clean Technology 2010
T.C. Wang, H.Y. Kang, H.P. Wang, J.G. Jou, J.L. Wei
National Cheng Kung University, TW
desulfurization, nanosize ZnO, XANES, EXAFS
Thermal efficiencies of an integrated gasification combined cycle (IGCC) process can be enhanced with high-temperature desulfurization. Nanosize, sub-nano (clusters) and atomic-dispersed ZnO has been prepared for the high-temperature desulfurization. An enhanced absorbance of the nanosize ZnO at 9668 eV is found by X-ray absorption near edge structure (XANES) spectroscopy (Figure 1). ZnO clusters are also observed in the channels of MCM-41. By temperature programmed sulfurization (TPS) and oxidization (TPO), it is found that the nanosize ZnO can be effectively sulfurized and regenerated (with air) at 940-950 K (Figure 2). The smaller ZnO clusters in MCM-41 can be sulfurized at relatively lower temperatures (700-820 K). The atomic dispersed ZnO on TiO2 having the strong metal-support interactions cannot be sulfurized at the temperature of < 960 K, and interestingly, regenerated at much lower temperatures (i.e., <650 K). It seems that the nanosize or atomic dispersed ZnO may be desired for the high-temperature desulfurization especially for a high efficiency IGCC based electric power generation.