Synthetic Chars for Studies of Char Combustion Mechanisms. Quarterly Technical Progress Report, March 1-May 31, 1986

摘要

The production of uniformly sized, spherical particles of glassy carbon for use as synthetic chars in the study of char oxidation processes has been demonstrated in previous reports. An important observation has been that, in spite of the apparent similarity of the char particles, the combustion behavior varies dramatically from particle to particle. When dropped into a hot oxidizing atmosphere, some particles ignite and burn rapidly at temperatures significantly higher than the reactor wall temperature while other particles burn at temperatures only slightly greater than that of the wall. This variability was attributed to differences in the spatial distribution of the porous structure of the char particles. Even though the rates at which the particles burned differed dramatically, it was observed that the intrinsic reaction kinetics for all particles obey the same rate law. Moreover, the rate law observed corresponded to that reported two decades ago for the combustion of pyrolytic graphite. During this reporting period, we have focused on eliminating ambiguities in the characteristics in the properties of the synthetic char and its combustion behavior. The fact that the intrinsic reaction kinetics inferred from the initial surface area were well correlated with a single rate expression in spite of this large change in the BET area suggests that much of this area is not active in the high temperature oxidation of this char. 3 figs., 1 tab. (ERA citation 11:003763)