Kinetic Modeling of CO₂ and H₂O Gasification Reactions for Metallurgical Coke Using a Distributed Activation Energy Model

Abstract

A distributed activation energy model (DAEM) was applied to the kinetic analysis of CO 2 and H 2 O gasification reactions for pulverized metallurgical coke. The results of the scanning electron microscopy observations and CO 2 gas adsorption suggested that the gasification reaction occurs at the particle surface. Therefore, a grain model was employed as a gasification reaction model. The reaction rates of CO 2 and H 2 O gasification were evaluated based on the DAEM. The activation energy changed as the reaction progressed and hardly depended on the particle size. The activation energies were 200–260 kJ/mol in CO 2 gasification and 220–290 kJ/mol in H 2 O gasification. The frequency factor of H 2 O gasification was approximately 10 times larger than that of CO 2 gasification, regardless of the progress of the reaction. At the same activation energy level, the frequency factor showed a higher value with a decrease in the particle size. This result was consistent with the theory of the grain model and indicated that the gasification reaction of the pulverized coke with a micrometer scale occurs on the surface of the coke particle. Furthermore, the value predicted by the DAEM was in good agreement with the experimental one.

Effects of Additives on Coke Reactivity and Sulfur Transformation during Co-pyrolysis of Long Flame Coal and High-Sulfur Coking Coal

“…As a porous solid, the pore structure of coke is the key factor affecting the reaction rate of CO 2 gasification. In the gasification process, CO 2 diffuses into the pore structure of coke and gasification reaction occurs when it comes into contact with the active center on the pore surface. , Therefore, the better-developed pore structure will cause a more sufficient gas–solid contact and easier gasification reaction. Figure shows the porosity of coke obtained after the CO 2 gasification reaction at 1100 °C.…”