Measurement and control of NOx emissions at two AC electric arc furnaces

Abstract

Nitrogen oxides (NOx) are important air polluting gas species. The emission of nitrogen oxides from industrial plants is strictly regulated in most industrial countries around the world and the emissions limits have been and will be lowered further in the future. Therefore it is important to know typical emissions values of processes like electrical steelmaking. In a second step it is also vital to investigate measures to control and reduce the NO x emissions of the electric steelmaking process. This will ensure the ability to compete with other steel production technologies and also with alternative production sites. In this paper the results of measurements and trials regarding the formation of NOx in the electric arc furnace (EAF) are reported. The measurements and trials have been conducted at two European industrial EAFs and their goal was to investigate the influence of current and modified operational practices on the emission of NOx at these EAFs. The results of the work performed have lead to control strategies to minimize NOx formation within the electric steelmaking process. © 2011 ISIJ.