Isotopic steady-state and step-response study on carbon gasification catalyzed by calcium Original Research Article

Isotopic steady-state and step-response (SR) experiments have been performed with calcium containing carbon samples with different metal content and sintering degree. The SR results: (i) rule out the CaO2/CaO mechanism; (ii) support the mechanism for the CO2-carbon gasification catalyzed by calcium previously proposed, confirming that CaCO3 is the active species; (iii) provide a measurement of the rate constants of the steps involved; and (iv) include additional steps in the reaction mechanism. SR can be used to determine the catalyst working active sites under experimental conditions where catalyst carbonation does not occur. However, they can provide erroneous results if the reaction conditions favour the catalyst carbonation.