Reactivities of several carbonaceous materials for their combustion catalyzed by potassium salts on perovskite type oxide

Catalytic activities of potassium carbonate and sulfate were studied for the combustion of several carbonaceous grains such as activated carbon, carbon black, graphite, and coal chars (Taiheiyo, Illinoi, and Newlands) by supporting salts either on the carbonaceous surface or a perovskite type oxide. The catalytic activities were remarkably influenced by the kind of carbonaceous materials. For all carbons and coal chars used in this study, these alkali metal salts supported on LSCMP exhibited higher activity than those supported directly on the carbons and coal chars. The activities of K2SO4/LSCMP at 723 and 773 K were very low for the Newlands coal char calcined at 1573 K and graphite in comparison with those for other coal chars and carbons calcinated at 873 K. However; the graphite and Newlands; coal char calcinated at 1573 K were burnt completely by K2SO4/LSCMP at 873 and 823 K, respectively, with 1% O-2 in N-2. The temperature for the rapid increases of the activity agrees with that of SO2 evolution through the reductive decomposition of K2SO4 supported on LSCMP, while no evolution of SO2 was observed on graphite. Hence, the reactivity of carbonaceous grains appears to be reflected by the temperature for rapid increases of both catalytic activity and combustion rate in the catalytic combustion by K2SO4.