Discrete particle simulation of solid flow in a melter-gasifier in smelting reduction process

Smelting reduction process is one of the promising technologies that produce liquid iron with advantages in the reduction of costs and adverse effect on environment. In this process, the main reactor of Melter-Gasifier (MG) involves complicated multiphase flow, heat and mass transfer phenomena, in which solid flow plays a dominant role. In this work, the solid flow behavior in an MG is investigated by discrete particle simulation under different conditions. The results show a good agreement with the observations in experiments. It reveals that three stagnant zones are formed: one is at the MG central bottom, and the other two are located on the side walls. The analysis indicates that charging method, MG geometry, and particle-wall frictional force are factors affecting the size of the stagnant zones on the side walls. Rolling friction does not affect solid flow much. Particle scale analysis of solid flow and force structures is also conducted, showing that strong forces exist in the regions with low porosity. The analysis of particle mass fraction shows that at the MG upper part, HCI (hot compacted iron) particles dominate the MG center, and coal particles tend to distribute to the side walls.