A METHOD FOR THE DETERMINATION OF ACTIVE-SITES AND TRUE ACTIVATION-ENERGIES IN CARBON GASIFICATION .2. EXPERIMENTAL RESULTS

The aim of this part of the paper was to confirm by experimental results theoretically derived relationships for the calculation of true activation energies and the concentration of the various sites of carbon gasification as given in part I. For this purpose, the gasification kinetics of a pure model coke with carbon dioxide by variation of the partial pressure and temperature were studied. The results could be described by the oxygen exchange mechanism. Temperature programmed desorption studies were performed after pregasifications of the model carbon at various temperatures and up to various carbon conversions. The true activation energy of the desorption step was calculated from the results of the temperature programmed desorption studies alone, and additionally by combined application of results from gasification kinetics and temperature programmed desorption. In both cases the same value of 85 kcal mol-1 was found. This and further results underline the validity of the theoretically derived equations. A remarkable result also was that the gasification rates at various carbon dioxide partial pressures are independent of the partial pressure, if they are related to the relevant concentration of C(O) complexes measured by temperature programmed desorption. © 1990.