FEM analysis of the anode connection in aluminium reduction cells

Abstract

Achieving voltage savings over the anode assembly in an aluminium reduction cell, particularly at the anode connection, is a worthwhile approach within a wider programme of improvement in energy efficiency. Experiments carried out using operating cells are very difficult and expensive, however finite element method (FEM) simulations as used in this study are a cost efficient and accurate method to understand the behaviour of the anode connection, and to identify the constraints to voltage savings. This study investigates the impacts of stub deterioration and yoke stiffness on the anode connection and hence the performance of the anode assembly. An ideal stub diameter for the investigated configuration was found, and the increased voltage drops for various level of stub deterioration were identified. The results show that a yoke cross-bar with reduced height and hence reduced stiffness decreases the tensile stress developed in the carbon anode, which lowers the risk of anode cracks. A limit for stub service life is suggested, showing a potential saving of US$0.8m annually.