ID 28

Nozzle Layout Optimization in a BOF Evaporation Tower via CFD Simulation

 

Abstract:

The BOF (Basic Oxygen Furnace) semi-dry de-dusting process is widely used in the steel industry, where high temperature flue gas enters the evaporative cooling tower, and water is sprayed to cool gas. Improper nozzle layout often results wall wetting, caused by injected liquid imping onto the side-walls. This will eventually lead to dust lumping off the wall due to the dense particulate content of the gas. Serious dust lumping severely deteriorates the flow pattern, and may ultimately block the tower. Thus, proper nozzle layout is a key success factor for this process. Conventionally, the nozzle layout is a uniform array, and lance insertion distances are often determined based on engineering experience, which does not consider recirculation in the tower. In this study, the gas cooling process in a BOF evaporation tower was simulated using a CFD (Computational Fluid Dynamics) model to predict the gas-liquid-wall interaction. A focus of this work was to optimize the nozzle layout and determine the lance insertion distance to avoid wall-wetting and eliminate the dust blocking. The model has since been used to design the nozzle layout in more than 15 BOF evaporation towers. On-site feedback demonstrates the model can dramatically reduce dust lumping due to spray wall-wetting.