Investigation of Pellet Shape on the Hydrogen Reduction of Iron Oxide Using Mathematical Modeling and Image Processing

Abstract

Due to environmental concerns and climate change, the use of hydrogen gas in the reduction of iron oxide has gained more attention recently. Many factors can affect the reduction of iron oxide pellets, and among them, a few studies have considered the shape of iron oxide pellets as a parameter. To evaluate how much the pellets may diverge from their ideal state, the circularity of the pellets is evaluated in this study using an image processing technique. Although this falls to as low as 0.75 in some cases, the computed average circularity of the pellets is 0.96. Afterward, considering that the reaction is non‐catalytic, mathematical modeling is used to develop an unreacted shrinking core model with three interfaces. The examination of the pellet's shape is conducted using this model, resulting in relative errors of 11.13% and 25.02% for the total conversion time at shape factor values of 0.9 and 0.8, respectively. Finally, the impact of the shape factor is demonstrated by varying each of the process parameters, including temperature, pressure, reduction gas composition, and pellet size.