Characteristics of Alkali and Alkaline-Earth Metals for the Catalytic Gasification of Coal Char in a Fixed-Bed Reactor

The effects of temperature, catalyst type, and catalyst loading on the gasification of coal char were investigated in a fixedbed reactor. The effects of catalyst dispersion, Brunauer-Emmett-Teller (BET) specific surface area, and crystallite constituents of Jinyou coal char with different loadings of K and Ca were also analyzed by energy-dispersive X-ray analysis (EDX), N-2 adsorption at 77 K, and X-ray diffraction (XRD). Results showed that K2CO3 could increase the gasification rate significantly for gasification temperatures greater than 850 degrees C. Cation species could have a significant influence on the catalytic activity. The reactivity of the coal char increased continuously with catalyst loading and resulted in a loading saturation level (LSL) of 10% for K. Compared with the raw char, K and Ca added to Jinyou coal decreased the BET specific surface area. Moreover, K and Ca added to Jinyou coal altered the crystallite constituents during the process of coking and gasification, which indicated that some K and Ca reacted with minerals in the Jinyou coal during the process of coking and gasification and partly deactivated the K and Ca.