Estimation of the hot face temperatures of the blast furnace hearth by an inverse method

The operation and campaign life of a blast furnace are influenced by the inner conditions of its refractory-lined lower part, the hearth, but the internal state is unknown due to the lack of sensors that could stand the hostile conditions in the furnace. The present work makes an attempt to shed light on the hot-face conditions of the hearth lining by applying an inverse dynamic heat transfer model. The hearth sidewall below the tapholes was studied, considering different position around the hearth periphery at different heights. The inverse problem focuses on the estimation of the temperature at the internal surface of the hearth lining. Simulated tasks were studied to validate the model’s ability to reproduce the temperature at the inner boundary. The model was found to estimate the hot-face conditions quite accurately, but, as expected for any inverse model, the performance degraded when noise was added to the measurements. Using thermocouple data from an operating blast furnace, the hot-face temperatures of the hearth sidewall were reconstructed by solving the inverse problem independently for each location, aggregating the results into a thermal map that illustrates the temperature dynamics of the hearth. Despite being preliminary, the study has already revealed interesting findings about the motion of hot and cold spots on the inner hearth lining.