On the use of flame analysis and optical variables for an optimized operation in ladle furnace preheating process

In this work, the theoretical fundamentals and the experimental results of combustion control for a ladle furnace preheating process are presented, featured by a high fuel consumption and their subsequent high operational temperatures. The ladle furnace preheating process maximize the ladle´s inner refractory temperature, via combustion. The highlights of the closed loop solution are the flame spectrum analysis, the calculation of a set of optical variables and the process optimization using the optical information. These optical variables of flame temperature and radiation, are used as the inputs of an inferential sensor of the key process variable: refractory temperature. Simulation via a Hammerstein first-order model and the experimental results, reveals the suitability of the proposed approach. We obtain near 9% increase with respect to the conventional open-loop operation, for the refractory temperature.