EAF process optimization based on continuous analysis of off-gases and real-time control of chenical package parameters: the case of TAMSA

Abstract

Techint Goodfellow Technologies (formerly Stantec) implemented their Goodfellow EFSOP™ system at Tubos de Acero de Mexico, SA (TAMSA) in late 2002. The technology was used to optimize the use of chemical energy within the electric arc furnace (EAF). The project was a success providing TAMSA a 4.4% reduction in conversion costs (oxygen, methane, electricity and carbon) and a reduction of 1 minute in power-on-time. Subsequently, in late 2003, Techint installed and commissioned their KT-Chemical package at TAMSA. The Goodfellow EFSOP™ system was again used to optimize chemical energy usage within the EAF. The Goodfellow Expert Furnace System Optimization Process (Goodfellow EFSOP™) is a proprietary process that uses continuous off-gas analysis, along with process monitoring to optimize the use of chemical energy within the electric arc furnace (EAF). Optimization is achieved by adjustments to the electric furnace process (carbon charge practice, injected carbon, methane and oxygen), according to analysis of off-gas measurements. Further benefits are provided through dynamic control of oxygen and methane in response to real-time off-gas composition. This paper details the application of the Goodfellow EFSOP™ optimization process to the KT chemical package at TAMSA and concludes with a summary of the achievements provided by the merging of these two technologies. Ultimately, a reduction in electrical energy (12.3%) and methane consumption (33%) were achieved at TAMSA. Economically, these savings outweigh the increase in total carbon usage (11%) and oxygen consumption (14.6%) and have provided an overall 2% reduction in power-on-time (1 minute), considering an increase in tapping weight by 11% (from 142 to 158) tons liquid steel. Iron oxidation has also been reduced, as indicated by slag chemistry, from over 40% initially to 32% at present. Electrode consumption has been reduced by 9%.