Numerical analysis of powder deposition in blast furnace by using multi-fluid process simulator

Blast furnace is a principal metallurgical reactor in ironmaking process, and usually treated as a counter current moving bed reactor. In the lower part of this reactor, flows of gas, solid, liquid and powder exist at the same time. With recent increase in pulverized coal injection, operation problems due to deposition of fine particles in this zone have been arising. The authors developed a process simulator of blast furnace treating more than four different phases that had individual flow mechanisms. In this study, mathematical formulations describing powder deposition rate by difference between adhering and departing rates has been introduced, and the simulator is able to handle flowing and deposited powders separately. It is assumed that the deposited powder phase has flow pattern identical to the solid one because it is trapped in the interstice among packed particles or on the particle surface. The simulator successfully reproduces temperature field and operation status of the blast furnace at different pulverized coal injection rates. The simulation results revealed the behavior of powder in the blast furnace, such as distributions of static powder hold-up, concentration of flowing powder, major zones of powder deposition, and so on.