Siemens Optimizes Furnace Operation for SDI Roanoke with Holistic Process Model Lomas Offgas Monitoring

In April, the U.S. steelmaker, Steel Dynamics Inc. (SDI) or Roanoke, VA, issued the final acceptance certificate for the Simetal EAF Heatopt system installed by Siemens. The newly-developed holistic process model combines modern measurement technologies like the Lomas off-gas analyzer with an intelligent control strategy. The system is used to monitor the off-gases from an electric arc furnace, and makes an important contribution toward optimizing the process. It has reduced conversion costs by more than 1.5 USD per ton. This was the first time that a Lomas system had been installed in an electric arc furnace. Siemens is already the market leader for installing this technology in LD steelmaking converters.

The Lomas system and an integrated off-gas flow speed meter continuously monitor and analyze the flow off-gas from a furnace. The measured values are fed into the holistic process model and evaluated. This gives the operator’s personnel continual, up-to-date information about the progress of the process in the furnace. The system also generates recommendations for adapting and optimizing the process control. Output deficits arising in the process can be corrected by closed-loop control of the injection of natural gas, oxygen and carbon injection by means of burners and lances. In this way, the consumption of energy and electrodes can be reduced, and the use of oxygen, coal and combustion gas optimized for the process. This increases the efficiency and productivity of the electric arc furnace as well as the output of liquid steel. The Lomas system also increases operational safety by quickly detecting hazardous gas compositions forming during the melting and decarburization processes.