Experience with Lengthy Pot Hibernation at Alcoa Baie-Comeau

摘要

Two AP18 pots were put into hibernation state from a normal production state for a period of 4 weeks. They were then woken up and successfully transitioned back to their normal operation. During the hibernation period, the pots were operated at normal line current and the bath temperature maintained around 840-860°C. This paper presents the pot thermal behavior and responses to different phases of the hibernation process from transi-tioning into a hibernation state, maintaining a stable sleep state, to waking up and transitioning back to a normal production state. Special adjustments were necessary for each phase during the hibernation process. Interesting observations, unanticipated events, and effective counter-measures are also presented and discussed.