A. Cuesta et al., CORRELATION BETWEEN ARRHENIUS KINETIC-PARAMETERS IN THE REACTION OF DIFFERENT CARBON MATERIALS WITH OXYGEN, Energy & fuels, 7(6), 1993, pp. 1141-1145
Correlation between Arrhenius kinetic parameters is often found in coa
l and char reactions, to such an extent that Essenhigh and Misra have
recently suggested (Essenhigh, R. H.; Misra, M. K. Energy Fuels 1990,
4, 171-177) that these parameters are autocorrelated. In order to thro
w additional light on this point, a self-consistent set of kinetic dat
a for the reaction of carbonaceous solids with oxygen, determined by t
hermogravimetric analysis, is presented and analyzed in this work. The
wide range of carbon materials under study allowed to broaden the sco
pe of correlations with respect to numerous previous studies of this r
eaction. A generalized correlation between Arrhenius parameters (appar
ent activation energy and preexponential factor) was found. Unlike pre
vious reports, existence of a systematic curvature in the correlation
plot was detected. Thus, optimum fitting to a curve obeying a power eq
uation rather than to a straight line was attempted. An active-centers
model adapted to the graphite structure was used to justify the occur
rence of compensation effect, differences in behavior among carbon mat
erials being explained as a function of the relative predominance of t
he various types of factors controlling the reactivity of these solids
against oxygen.