Optical emission spectroscopy as a tool for process control of steelmaking burners

Abstract In contemporary steelmaking, burners are widely used for heating slabs in walking beam and annealing furnaces, heat-up of empty ladles, flame cutting of steel, as well as providing additional energy in electric arc furnaces. To facilitate the future of carbon-neutral steelmaking, a transition from natural gas-based burners toward hydrogen-based burners is essential to reduce the CO2 emissions associated with the burners. In addition to this transition, it is important also to optimize the burner practices that are used today, since the transition will take its time. To this end, CO2 reductions could also be realized with process control aiming toward more efficient use of energy and gas resources. This study presents how optical emission spectroscopy could be used for on-line monitoring and process control of the burner flame. A case study of oxy-fuel cutting is presented, where optical emissions from H2O, C2, FeO, Na, and K together with thermal radiation were observed. The flame’s properties, such as temperature and radiative heat transfer, identification of the flame species and impurities, and detection of rapid changes in the flame are analyzed from the OES data