Detecting, Identifying and Managing Systematic Potline Issues with Generation 3 Process Control

Due to the nature of the process, aluminium smelting can have many issues/abnormalities/problems. One type is systematic issues, which are those that occur on multiple pots simultaneously and can result in prolonged issues across a potline if not identified early. However, detecting and identifying these issues can be a difficult task for smelter engineers and management, particularly when information sources are not recorded, integrated and available in a centralised location. In addition, they are often not displayed in a way that is convenient for tracking and identifying systematic problems. For example, an increasing trend in cryolite ratio (CR) on all pots can be difficult to spot if graphical CR trends are only displayed for individual pots, or worse, in a tabulated format. This paper presents two case studies in detecting systematic issues in smelting process using the Generation 3 process control system that highlights the importance of a centralised data location and appropriate data presentation. The cause of the systematic issues and the actions taken to manage the impact will also be discussed.