Metallurgical Coke Gasification by Carbon Dioxide under Nonisothermal Conditions: A Kinetic Study

Abstract

Metallurgical coke gasification by carbon dioxide was kinetically investigated through the use of thermogravimetric analysis under nonisothermal conditions. The results showed that the activation energy, gained by the Cai-Chen iterative model-free method, was estimated to be 183.15 kJ·mol-1. Notwithstanding, the mechanism function f(α) cannot be directly determined due to the fact that f(α) and the pre-exponential factor Aα were lumped together as [Aαf(α)]; this situation may be tackled by means of the master-plot methods. The most probable mechanism function, determined by the Málek master-plot method (based on Z(α) master plots), was discovered to be the Johnson-Mehl-Avrami equation. The usefulness of the compound kinetic calculation technique founded upon complemental application of the Málek master-plot and Cai-Chen model-free methods in estimating reaction kinetics of metallurgical coke gasification was verified. The comparison between original and reconstructed kinetic curves judged the accuracy of the gained kinetic parameters. By means of gained nonisothermal kinetic results, the forecasting of kinetic curves in isothermal as well as nonisothermal conditions was performed. In this work, new kinetic equations were presented and applied to reproducing and forecasting kinetic curves.