Reaction between CO₂ and coke doped with NaCN

The role of NaCN as a catalytic precursor in the reaction between coke and carbon dioxide is examined. The experimental work included determination of reaction rate, examination of the chemical stability of NaCN and characterization of coke at various stages of reaction. The extent of sodiumcarbon contact was physically modelled by examining the distribution of potassium in the interior of a KCN doped coke sample after partial reaction. Physical evidence is presented to demonstrate that at 1123 K, the vapor cycle mechanism is the predominant mode of catalysis with catalyst concentration and specific surface area being the two most important directly measureable rate determining factors. Analysis of the rate data on the basis of a structural model demonstrated that when NaCN was used, the enhancement of the rate was inadequate for the diffusion of CO₂ through the porous coke to be important.