THE CARBON-CARBON DIOXIDE REACTION - AN EXTENDED TREATMENT OF THE ACTIVE-SITE CONCEPT

The paper presents results on the kinetics of gasification of a polyvinylchloride coke (heat treated at 1600-degrees-C) with carbon dioxide. In addition to the kinetics, temperature-programmed desorption of quenched carbon-oxygen surface complexes was studied. It is shown that the total concentration of active sites, c0, can be determined by a combined application of Langmuir-Hinshelwood kinetics and the active site theory, whereby the total concentration of carbon-oxygen complexes, c(0)0, is measured as described above, c0 is independent of the carbon dioxide partial pressure, but it decreases exponentially with temperature. With the knowledge of this temperature dependence, the true activation energies of the dissociation, and the desorption step of the gasification reaction can be calculated. The developed active site concept seems now to be completely self-consistent.