Effects of Flow Distributor Position and Loosener Configuration on Particle Flow Behavior in a Hydrogen-Based Direct Reduction Shaft Furnace

This study investigates the effects of flow distributor placement and loosener configuration on particle-flow behavior in a hydrogen-based direct reduction shaft furnace using the discrete element method (DEM). A three-dimensional industrial-scale furnace model based on a MIDREX-type geometry was established, and four representative structural configurations were examined by varying the flow distributor position and loosener setting. The results show that flow distributor placement is the dominant factor controlling particle descending behavior and particle-flow uniformity. When the flow distributor was located in the cooling zone, the flow uniformity index reached 0.875, which was 40.9% and 20.9% higher than those for the transition–cooling interface and transition-zone configurations, respectively. Particle trajectory analysis indicates that the effect of flow distributor position is mainly confined to the region above the device, with limited influence on the lower burden trajectory. Although the loosener has little effect on particle-flow uniformity, it significantly suppresses particle degradation. Under the transition-zone flow distributor configuration, the predicted powder formation ratio decreased from 3.89% to 2.97% after introducing the loosener, corresponding to a relative reduction of 23.7%. Overall, among the four representative configurations investigated in this study, positioning the flow distributor in the transition zone while retaining the loosener provides a more balanced compromise between burden-flow regulation and powder suppression for shaft furnace design and industrial operation.