Pot Control System

Location

Kitimat, British Columbia

Customer

Alcan Primary Metal Group

Completion Date

July 1998

Cost

$4,700,000

Background

Kitimat Works is a production unit of Alcan Primary Metal Group. The design of the plant dates back to the Soderberg technology available in the early 1950s. Its annual capacity is 272,000 tons. The existing pot control system was based on a centralized computer and I/O system, slow data acquisition rates, and manual feed of alumina to the reduction pots. Alcan wished to upgrade their pot control to improve efficiency and ease of compliance to environmental requirements.

Project Scope

The requirements included high-speed and high-precision analog data handling, high-order bandpass filtering, precision anode positioning control, and automated alumina feed employing point breaker feeder technology. I/O subsystems, networks and intelligent controllers needed high reliability, voltage isolation, noise immunity, and operation in extreme ambient temperatures.

Universal Dynamics assisted Alcan in selecting the critical hardware and software components of the I/O and control subsystems. We provided preliminary engineering, detailed design, construction management, software implementation, commissioning, and project management services for electrical distribution, instrumentation, networked control systems, and control software for the project.

Benefits from the Project

The new control system provides improved efficiency and stability of cell control, which results in reduced costs of production, longer cell life, and reduced anode effects. The vastly improved reliability, speed and accuracy of the data collection and analysis enable advanced area control strategies to be executed.

Highlights

Key components of the system include electrically isolated and environmentally rugged I/O modules and processors at each cell. A dual-ring fiber-optic network in each potroom area connects these I/O processors to an industrial control PC that hosts the data analysis and control logic for the cells in that area. A central control computer collects the operating data from all area PCs, calculates Alcan's key strategies for each cell and sends set point changes to the area PCs.