Numerical Analysis of Complicated Heat and Mass Transfer inside a Wustite Pellet during Reducing to Sponge Iron by H2 and CO Gaseous Mixture

Heat and mass transfer through a wustite pellet during converting to sponge iron was investigated. Pellet was reduced by a gaseous mixture containing CO and H2. The grain model was considered to simulate gas-solid reaction rate. A finite volume method (FVM) was implemented for solving the governing equations. The heat transfer mechanism around the pellet includes radiation and convection and within the pellet, effective heat transfer is considered as a blend of particles conduction and intraparticle radiation. Heat and mass distribution along the radius of pellet for two cases of reducing gases composed of pure H2 and pure CO was investigated. Local fractional reduction through the pellet was plotted to examine the heat and mass transfer behavior within the pellet and find their relevance with reduction degree. Afterwards, the impacts of pertinent parameters including gas ratio, pellet size and porosity were studied.