An investigation was undertaken to examine gas formation and gas temperature distributions at different vertical and horizontal levels within the combustion zone and above it in a coke-fired, cold blast, experimental cupola. Two factors which markedly affect the conditions in the combustion zone were studied in this research: coke size and blast rate. Two coke sizes and two blasts rates were used. The data obtained were tabulated and analyzed graphically. The results showed that coke size as well as blast rate had a significant influence on the gas composition and temperature distribution within the combustion zone and above it. The coke size and the blast rate influenced the height of the combustion zone. The overall combustion process was found to be limited by the rate of oxygen diffusion to the coke surface. The process of mass transfer of oxygen to the coke surface was considered mathematically, and an analytical expression was found for the average oxygen concentration as a function of height within the cupola. The fitted solution of this equation showed good correlation with the average distribution of the oxygen concentration at different vertical levels near the cupola wall. For the cupola used in this research, and from a combustion efficiency point of view, the larger coke size and the higher blast rate were found to be better because they provided: better penetration of the blast, higher gas temperature, and a lower carbon monoxide content in the reduction zone.
