DDPM Simulation for Fluidization Behavior and Reduction of Iron Ore Fines with Hydrogen in the Fluidized Bed

In this paper, the hydrogen direct reduction of iron ore fines is numerically studied by using the Dense Discrete Phase Model (DDPM) in the fluidized bed. The fluidization behavior at different inlet gas velocities (Ug) as well as the influence of Ug and hydrogen concentration on reduction degree (RD) are comprehensively investigated. The result indicates the increase of time-averaged solids volume fraction for the same cross-sectional heights with increasing Ug when the bed height (H) exceeds 0.06 m. Furthermore, the reduction rate of mineral powder increases with higher Ug value, and the RD reaches almost 100 pct after 4000 seconds of reduction time with Ug ranging from 0.35 to 0.65 m/s. The reduction rate increases noticeably with the increase of hydrogen concentration in the range of 10 to 100 pct, and Fe2O3 can be completely converted to Fe under condition of 65 pct H2 concentration after 4000 seconds. Moreover, higher H2 concentration leads to faster rate of Fe2O3 consumption and Fe production. The mass fraction peak values of Fe3O4 and FeO are in the range of 0.29 to 0.34 and 0.21 to 0.24 under different H2 concentrations, respectively.