Automatic excess oxygen control in steel reheating furnaces. Final report

John Niska & Anders Rensgard

This project investigated a new technique for automatic control of the excess air and oxygen in steel reheating furnaces using tunable diode laser absorption spectroscopy (TDLAS). These instruments measure in-situ, average gas concentrations, which makes them suitable for process control. Several trials have been made with 2 commercial TDLAS oxygen analysers (from Siemens and NEO). Both instruments gave good average oxygen concentrations across the furnaces, but combined temperature and oxygen measurements were associated with problems. Automatic excess oxygen control was successfully proven in a pilot trial at Mefos, but instrument problems delayed industrial trials of the technique.