Casthouse Ventilation Design for the Production of Air-Cooled Aluminium Sows

The Aluminerie Alouette Inc. (AAI) smelter in northern Quebec, Canada recently completed a major plant expansion that includes a new casthouse for the continuous production of low-profile, air-cooled aluminium sows. The radiation and convection heat release of 15 MW to the workplace from the aluminium metal solidification and cooling is significantly higher than that experienced in the traditional water-cooled casting process where the majority of the heat is removed by the cooling water. The design of the casthouse ventilation system presented many challenges for achieving acceptable workplace temperatures, and limiting worker exposure to heat stress and hydrogen fluoride (HF) gas for both summer and winter conditions. Computational Fluid Dynamics (CFD) modelling was used extensively to guide the design of the building ventilation system. The casthouse has been operating successfully since start-up in 2005. Field measurements verify that the CFD modelling closely predicts the workplace temperatures throughout the facility. The simple ventilation control strategy is fully automated and provides acceptable temperature levels in the casthouse. There are no periods throughout the year where it is excessively hot or cold. HF concentration levels are well below the threshold levels.