Numerical Simulation of Flash Reduction of Iron Ore Particles with Biomass Syngas

Abstract

Flash ironmaking technology has recently been developed to directly reduce in-flight hematite ore particles in a few seconds using gas reductant. Using biomass syngas as the reducer of this technology can decrease fossil fuel consumption and carbon dioxide emissions. This study investigated the flash reduction behavior of hematite particles using biomass syngas in a drop tube reactor based on a three-dimensional Eulerian-Lagrangian CFD model that includes heat and mass transfer, heterogeneous and homogeneous reactions, radiation, and interactions between gas and particles. The effects of the reduction temperature, biomass gas composition, and pressure on the reduction process were explored. Moreover, the particle characteristics and reaction rate during the flash reduction process were presented. The results showed that the water gas shift reaction proceeded in the reverse direction, and the methane steam reforming reaction proceeded in the forward direction during the flash reduction process. Under biomass steam gasification syngas, the reduction degree of hematite ore particles reached 95.90% within 1.4 s at 1 573 K. Also, a higher temperature and operating pressure favored the reduction process by accelerating the reduction rate of hematite. These results provide a theoretical basis for using biomass syngas in flash ironmaking technology.