Control Technique of Coke Rate in Shaft Furnace by Controlling Coke Reactivity

The shaft furnace, which is a scrap melting furnace, plays an important part as an energy supplier in a steel works because the shaft furnace produces high calorie gas. The shaft furnace is required either to reduce the coke rate or to increase the exhaust gas calorie, corresponding to the energy balance in the steel works. Because the coke rate and exhaust gas calorie are determined by coke gasification reactivity, the reactivity control technique is very important. In this study, the coke surface was coated with CaCO3, Fe2O3 and SiO2 to control coke reactivity, and the gasification rates were measured at 1 573-1 773 K. As the results, the gasification rate was accelerated by CaCO3 and Fe2O3 and decelerated by SiO2. The acquired gasification rates were applied to a one-dimensional mathematical model of the shaft furnace. The shaft furnace operation with controlled coke reactivity was simulated, and the effects of coke reactivity on the coke rate and exhaust gas calorie were estimated.