INFLUENCE OF STRUCTURAL PARAMETERS OF COAL CHAR ON K-CATALYZED AND CA-CATALYZED STEAM GASIFICATIONS

Various coal chars with well-characterized surfaces were subjected to K- and Ca-catalyzed steam gasifications at 800 or 850-degrees-C in atmospheric flow of equimolar H2O-He or H2O-H2 mixture, to elucidate the relation between the reactivity and structural properties of char. The catalytic effect of Ca was sensitive to the preparation temperature of char and the kind of parent coal, while the activity of K was essentially independent of those. The catalytic effect of Ca was well correlated to the structural parameters of char, which represent surface area, surface hydrophilicity, and crystallinity. The result is discussed in comparison with our previous studies on Ni-catalyzed gasification of coal chars.