Numerical Investigation of Slag Flow Through a Coke Funnel Analog and Packed Bed
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Molten slag is a critical material generated during blast furnace (BF) ironmaking. Slag flow behavior in the lower part of BF is closely related to the selection of charge materials, coke packed bed permeability, process stability, productivity, and hot metal quality. To better understand slag flow behavior, a numerical approach was applied to characterize the slag flow through a coke funnel analog and further, in a packed bed. The funnel analog was used to represent the flow of molten slag through the inter-particle voids of a coke packed bed. A critical funnel neck size, through which no slag flowed was experimentally established and confirmed by numerical modeling. The effect of wettability on slag flow shows the existence of an optimal contact angle for smooth slag flow in a funnel. The model was then applied to provide a deeper understanding of molten slag flow behavior in a packed bed, e.g., visualization of accumulation, coalescence, and breakup of slag at a particle scale. Specifically, the results show that the flow characteristics of discrete slag droplets in the packed bed require a particular quantitative approach for estimating the slag holdup. Packing structure, including pore size and particle shape, significantly affects the occurrence of slag blockage and droplet size, even when overall bed porosity is maintained constant. Slag flow along the vertical direction of the packed bed has a pseudo-steady percolation velocity. These results highlighted that this numerical approach is very helpful to understand the slag flow behavior at a particle scale, providing insight into the general features of slag flow as droplets or rivulets.
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