On the Thermal Behavior of an Aluminum Reduction Cell During Electrical Preheating

This paper presents a thermal evaluation of a retrofitted aluminum reduction cell at the CVG ALCASA smelter. The aim of the study was to find the thermal response of the different components in the cell when loaded by joule heating from a petroleum coke resistor bed placed in between anode and cathode, working on a full current of 70 kA. A thermo-electrical approach was assumed for problem solution. For temperature and voltage drop calculations, a commercially available finite elements method (FEM) code was used. Loading conditions comprised time varying values of electrical resistivity of the coke bed as well as heat transfer coefficients, all functions of experimentally measured quantities such as voltage drop, air velocity, and external temperature. The results of the 3D one tenth cell FEM simulations show for low peak temperature values as well as a very non uniform distribution in the cell at the end of the preheating stage, urging for several process design changes already carried away.