Energy efficient operation of Aluminium furnaces

Secondary Aluminium melting offers significant energy savings over the production of Aluminium from raw resources. It takes approximately 5% of the energy to re-melt the Aluminium for product than it does to generate the same amount of Aluminium from raw material. However, the industry faces technical challenges for further improving the efficiency of secondary Aluminium melting furnaces and lacks tools that can aid in helping to understand the intricate interactions of combustion and heat transfer. The U. S. Dept. of Energy, Albany Research Center (ARC), in cooperation with the Argonne and Oak Ridge National Labs, the University of Kentucky, and with industrial support through Secat, Inc. of Lexington, KY (representing 8 Aluminium re-melt companies) built and operates a test-bed reverberatory furnace to study efficiency issues in Aluminium melting. The experimental reverberatory furnace (ERF) is a one ton nominal capacity research furnace capable of melting 1000 lbs per hour with its twin 0.8 MMBtu/hr burners. Studies in the ERF include melt efficiency as a function of combustion space volume, power input and charge alloy. This paper details the experimental equipment, conditions, procedures, and measurements and includes results and discussions of melt efficiency studies. Specific results reported include an analysis of the efficiency of the furnace as a function of power input and the effect that changing combustion space volume has on melting efficiency. In conjunction with this, a computational fluid dynamics (CFD) model has been developed to simulate fuel combustion, heat transfer, gaseous product flow and the production/transport of pollutants and greenhouse gases (GHG) in an Aluminium furnace. Data from the ERF is utilized for computational model validation in order to have a high degree of confidence in the model results. Once validated, the CFD code can then be used to perform parametric studies and to investigate methods to optimize operation in industrial furnaces. Finally, an analytic analysis of the efficiency of the furnace under varying conditions was conducted to determine overall efficiency characteristics of the furnace.