| Description |
A novel flash ironmaking technology is being developed at the University of Utah aimed at producing iron directly from magnetite concentrate (< 100 μm) using natural gas in a flash ironmaking reactor in the temperature range of 1150-1600 °C. In this process, natural gas is partially oxidized by oxygen to generate a reducing gas mixture of H2 and CO as well as providing the heat required for the reduction of iron oxide concentrate. Computational Fluid Dynamics (CFD) models, coupled with experimental results, were first used to accurately evaluate the kinetic parameters of iron oxide particle reduction by H2, CO, and H2+CO mixtures. The nucleation and growth rate expressions were found to best describe the reaction kinetics of the concentrate particles in the interested temperature range. The reduction rate was also found to be inversely proportional to the particle size for the higher temperature range, while no particle size effect for the lower temperature range was found. The rate equations for reduction by the H2+CO mixtures were also developed using the rate expressions by individual component gases. An enhancement factor which is a function of temperature and partial pressures of component gases was introduced to account for the synergistic effects due to the presence of CO. A three-dimensional CFD model was developed to simulate the gas particle flow pattern, heat transfer, and chemical reactions inside a laboratory scale flash. The obtained rate expressions from the first stage of this work were used and verified in the CFD iv simulation. The temperature profiles and the reduction degrees obtained from the simulation results satisfactorily agreed with the experimental measurements. As an intermediate step to the full industrial-scale flash ironmaking reactor, the design of a pilot-scale flash reactor was investigated in this work. The verified rate expressions and CFD models were used for the design of a reactor with a capacity of 100,000 tons/yr of metallic iron. The CFD simulation provided information such as temperature and species distribution, gas and particle flow patterns that are essential for the proper design of reactor design |
