Development of a Computer Control System for the Aluminum Electrolysis Process

Summary

The state of an aluminium electrolysis cell is a vector of a high dimension because of the complex electro-chemical properties and the distributed nature of the cell. Some important phenomena in the cell can not yet be described in mathematical terms. The observations that can be implemented in a production plant are incomplete and uncertain. As many control actions must be carried out manually a good coordination between manual and automatic control is necessary.

In the development of a computer control system for an aluminium electrolysis plant the basis ideas from modern control theory guided the work although a proper application of modern methods was not possible. The structure of optimal control systems was followed. The systems has been implemented on a CDC 1700 computer and tested in a production line on a group of 20 electrolysis cells for a long period of time. A significant increase in productivity has been recorded. The structure of the system allows a very flexible cooperation between the plant operators and the computer and is suitable for programming.