Technico-economic analysis of cylindrical cathode collector bars with copper inserts in a Hall-Héroult cell

Authors: Lacroix, Olivier
Advisor: Fafard, MarioGosselin, Louis
Abstract: The cathode, located at the bottom of a Hall-Héroult cell, is responsible for nearly 10 % of the total cell voltage drop. Poor contact between the carbon block and the cast-iron layer surrounding the collector bars increase energy losses in the form of Joule heating. In addition, a non-uniform current density distribution inside the cell results in premature erosion of the carbon block extremities, limiting the cell’s life expectancy. This project aims to reduce the voltage drop and to improve the current density uniformity in the cathode assembly by improving the contact between the collector bars and the carbon block. To do so, a new cathode design using cylindrical collector bars with copper inserts is investigated using finite element modeling. The thermal expansion during the cell start up is used to generate contact between the collector bars and the carbon block, thus not requiring any cast iron or sealing operations. Different geometry configurations are explored using a thermo-electro-mechanical model to understand its behavior and to determine their effect on energy consumption and cell life expectancy. An economic analysis is also performed to evaluate the cost effectiveness of those configurations. The geometry is finally optimized to maximize the new design’s performance. Results indicate that a significant voltage drop reduction and a more uniform current distribution can be achieved by improving the contact quality between the carbon block and the collector bars.
Document Type: Mémoire de maîtrise
Issue Date: 2019
Open Access Date: 2 October 2019
Grantor: Université Laval
Collection:Thèses et mémoires

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