Advancement in Control Logic of Hindalco Low Amperage Pots

With increasing cell amperage and size, the cell control technology has also evolved to ensure good alumina dissolution and distribution. Renukoot smelter has about 60-year-old technology, being sustained through continuous upgradation in the design and the control system. Renukoot pots operate at a very high ratio of alumina feed to electrolyte volume as compared to modern smelters. This paper elaborates on the improvement in existing control software with prevailing hardware limitations. A new alumina feeding strategy was developed by incorporating the distributed feed approach consisting of underfeed and overfeed cycles. This resulted in reduced variation of alumina concentration from 1.68 to 0.89%, thereby increasing the cell stability with reduced electrolyte temperature variation and reduced tendency of sludge formation. It also maintains the alumina concentration on the leaner side, while maintaining the anode effect frequency. The new logic incorporates advanced statistics for making more accurate and quick decisions, with reduced human intervention.