investigating the reduction of barium sulfate using methane through the modified grain model

This research investigates the reduction of barium sulfate using methane under unsteady-state conditions employing the modified grain model. this model incorporates diffusion resistance for each grain and alters pellet structure due to differences in molar volume between solid reactant and product components. experimental validations were conducted at 915 and 1015 °c with 40% methane in a thermogravimetric apparatus. the reaction at 1015 °c was completed one hour earlier than at 915 °c. the model demonstrated high accuracy, with mean absolute errors of 5.2% at 915 °c and 9.7% at 1015 °c, compared to experimental data. after validation, the model predicted grain radius, porosity over time, and gas concentration distribution inside the pellet over time and height. the reaction resulted in a 9% decrease in grain radius and a 16% increase in pellet porosity.