Electrode Monitoring and Control System (EMACS)

EMACS significantly increases energy and current efficiency by dynamically measuring and adjusting anode currents. The system's real-time cell parameter visibility offers better understanding of cell operations, cell control and maximizes cell production.

EMACS uses an integrated network of signal processing systems, current and voltage sensors linked to a PC-based application via a high-speed digital network. A truly adaptable system, EMACS can be connected into existing control systems.

The sensors are non-contact, temperature compensated, sealed and maintenance free. Ambient magnetic interference can be rejected with additional sensors if required. Sensor installation is as simple as sliding them onto existing anode stems so no downtime is required.

As the sensors do not rely on measurement of a millivolt drop on the anode current path, there is no need to worry about contact resistance with the anode studs and transfer potential from the anode DC system. The sensors are also provide a robust output voltage of up to 5 Vdc with a much better noise rejection compared to the mV signals from the voltage tap measurement method.

Using a graphical user interface, the software offers improved reporting and analysis of cell room operations via real-time viewing and logging of sensor data. The system alarm capability ensures operators are able to respond promptly to process fluctuations. The system also offers comprehensive diagnostic and security features.

Mercury Chlorine Cell Applications

With EMACS, potential power savings are significant with typical system payback of less than one year based on:

Savings of up to 0.30 volts per cell
K factors as low as 0.07
Current densities greater than 11 kA/M2
Better cell optimization and problem analysis
Flexible operating strateg and ability to use off-peak power increased production

Reduced anode damage means reduced maintenance costs. Typical results also included reduced cell room air mercury losses, and less hydrogen generation.

Most significantly, operations report better process information from the system allow them to take earlier counter measures as well as improve their procedures to get better process performance.

Aluminum Applications

Optimization in aluminum smelters has typically been based on the only information available - voltage and pot line current. The EMACS system eliminates the inherent shortcomings of conventional millivolt taps while offering a better understanding of cell dynamics. System benefits include:

early detection of anode to metal pad short circuits'
optimization of the anode-cathode gap
visualization of metal pad movement
early detection of cell instabilities and 'sick pot' analysis
optimized alumina feed control for quenching anode effects and stabilizing pots

More information is available about EMACS applications under the Chlor-Alkali or Aluminum industry areas.

Future plans for EMACS include the release of a portable system that is currently under development. Universal Dynamics is actively seeking input from system users; please contact us if you would like to participate in this exciting project.

Related Literature

Papers/Articles

Advances in Anode Monitoring (PDF)
Current Monitoring System - Aluminum (HTML) (PDF)

Sample Projects

PPG Industries, Inc., Natrium Plant, New Martinsville, WV: AMACS system currently being installed.
An EMACS system has been installed in Washington state on an 18-anode aluminum pot.

EMACS demonstration systems are available to prove the extent of operational improvements that customers can achieve.