Save the date: 14.9.2021
Our head of research Dr. Matti Aula will present in EEC2021 31.8. at 9:10 am with two topics.
The first presentation is at 9:40 am:
Development of EAF injector and burner control based on on-line optical emission spectroscopy
The second presentation is at 12:00 pm:
Coupling EAF online modelling with OES measurements
The abstracts of the presentations can be found below:
Development of EAF injector and burner control based on on-line optical emission spectroscopy
E Rontti, M Aula and M Jokinen
In recent decades, some of the biggest advances in electric arc furnace productivity have been achieved with the use of injectors. Oxygen and carbon injection, as well as burners, provide a large chemical energy input to the furnace. Optimized carbon and oxygen injection increases the energy efficiency of the furnace by promoting energy transfer from the electric arc to the bath and protecting the sidewalls from radiation with slag foaming.
The purpose of this study was to develop a dynamic control system for the operation of carbon injectors and burners in the studied electric arc furnace by monitoring the amount of light inside the furnace. The aim with carbon injection control was to optimize the timing of injection. In burner control, the objective was to detect situations where the heating efficiency of the burner decreases significantly.
Control logics for both operations were developed based on process data and on-line optical emission spectrum measurement. The performance of the proposed control was evaluated by comparing it to the original control.
The results indicate that the developed carbon injection control could be applied in 62-68% of the studied heats, resulting in an average of 1.2 to 1.6 minutes of heating time with improved energy efficiency during a heat. For a studied burner, the control was able to detect an average of 2.0 minutes of inefficient operating time in 14% of the studied heats.
The initial analysis indicates that on-line optical emission spectroscopy could be used for electric arc furnace injector and burner control, and that significant savings could be obtained with the proposed control.
Towards dynamic modeling of the EAF process
V-V Visuri, M Aula, A Ringel, L Hekkala and T Fabritius
The electric arc furnace is the main unit process in scrap-based steelmaking. This work aimed at developing a fundamental mathematical model of the EAF process for online use. The model is based on stand-alone modules for 1) scrap melting, 2) gas-phase reactions in the freeboard, and 3) metal–slag reactions.
The description of scrap melting is based on energy and mass balances and accounts for the main heat transfer mechanisms relevant for the electrodes and gas burners. The gas-phase reactions are calculated using a Lagrangian method for minimization of Gibbs energy in the freeboard. The reactions between metal and slag are assumed to be controlled by mass transfer and the competitive equilibrium at the interface is solved using the effective equilibrium constant method.
The preliminary results indicate that the scrap melting module provides a realistic depiction of the main phenomena. The gas-phase reaction module was found to be in excellent agreement with earlier studies. In further work, the modules will be combined for the simulation of complete heats from charging to tapping.
