预煅烧对橄榄石生物质气化催化性能的影响

Effects of precalcination on catalytic activity of olivine in biomass gasification were investigated in a fixedbed reactor. The experimental results show that the catalytic activity of the olivine is improved by precalcination at higher temperature. The results of X-ray Diffraction (XRD), Local Scanning Electron Microscopy/Energy Dispersive X-ray Analysis (SEM/EDX), and Temperature Programmed Reduction (H2-TPR) indicate that the crystalline structure of the olivine is modified by the precalcination. The α-Fe2O3 formed on the surface of the precalcined olivine sample is due to the eduction of iron from the olivine structure (iron and magnesium orthosilicate) during precalcination. The distribution of Fe elements on the surface of the precalcined olivine particle becomes more uniform than that of the natural sample. The amount of reducible iron oxide on the surface of samples increases with the increase of precalcination temperature and time. It can be inferred that the increase of olivine catalytic activity after precalcination is attributed to the formation of α-Fe2O3. However, the antiattrition ability of the olivine particles decreases after precalcination at 800℃~1100℃. The optimal catalytic activity and anti-attrition ability can be obtained at the precalcination temperature of 900℃ for 4h.