Dependence of the intrinsic reactivity of metallurgical cokes to carbon dioxide on extent of reaction

The intrinsic reactivity to CO{sub 2} of a commercial metallurgical coke and cokes made in the laboratory from the same coal blend was measured as a function of the extent of reaction by using a small fixed bed reactor. Reaction rate parameters and coke surface area were measured at various extents of reaction to 75% carbon conversion. The intrinsic reactivity, defined here as the reaction rate per unit total surface area (g/m{sup 2}/s), was found to remain constant at about 2.0 {times} 10{sup {minus}7} g/m{sup 2}/s at 900 C after about 15--20% burn-off. During the initial period of reaction, up to about 15% weight loss, significant increases in the surface area of the coke were not accompanied by corresponding increases in the measured reaction rate. The activation energy for the reaction was in the range of 215--240 kJ/mol. It was also found that the intrinsic reactivity and surface area of cokes prepared in the laboratory using the battery feedstock coal blend used for commercial coke production, were very similar to those of the commercially prepared coke.