Analysis on Non-Uniform Gas Flow in Blast Furnace Based on DEM-CFD Combined Model

Blast furnace technology is currently aiming at low reducing agent operation so as to decrease CO2 emissions. At the same time, the inner volume of blast furnaces has frequently been enlarged so as to increase production rate in some countries, including Japan. Operating conditions designed for low reducing agent in a large blast furnace tend to cause unfavorable phenomena such as slipping of the burden and gas channeling due to the decrease in coke rate. Mathematical models help to clarify the in-furnace phenomena under these situations. From the above backgrounds, a new model has been developed that combines Discrete Element Method with Computational Fluid Dynamics (DEM-CFD) to simulate precisely the gas flow and solid motion in a blast furnace. The present study aimed to develop a three-dimensional mathematical model based on DEM-CFD for simultaneous analysis of gas and solid flow in the whole blast furnace. The unbalanced gas flow in the case of clogging of the particular tuyere was analyzed to clarify the circumferential unevenness in the lower part of the blast furnace. Based on the combined DEM with CFD model, the non-uniform gas flow in the lower part of the blast furnace was precisely evaluated.