Operation and simulation of pressurized shaft furnace for direct reduction.

Abstract

A laboratory scale shaft furnace was constructed for examining the operational characteristics. Some series of reduction experiments of iron oxide pellets with gas mixture of H2, CO and others were carried out under various operational conditions varying temperature, flow rate and composition of inlet gas and pressure applied. Overall data of operation and distributions of process variables were obtained for the steady-state operations. After cooling down the furnace, the pellets were sampled from various levels in the furnace. Then, the measurement of crushing strength and the observation of reduction fashion of the pellets were conducted.On the other hand, a one dimensional mathematical model was derived for the process simulation of the shaft furnace. The rate parameters for the reduction of the pellets and the side reactions which were measured by independent experiments were incorporated in the model. Reasonable simulation results were obtained for ordinary pressure operation when appropriate values of the rate parameters were given for the reduction of iron oxide pellets and side reactions.