EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

A real-time liquid level measurement system was installed at Dillinger Hütte Blast Furnace No 5. The method is mainly based on strain gauges along a vertical line on the lower BF shell and an analytical deformation model of the hearth. The method, developed by TMT and CRM, indicates both the total slag level and the pig iron level inside the BF hearth. The liquid level measurement allows to improve the tapping strategy by optimisation of the tap-to-tap time. In addition, the analysis of the trends serves to understand the relationship of liquid volume to level, and to evaluate the coke voidage in the BF hearth. The maximum liquid level is known so to guarantee a minimum gap to the tuyere level, to minimize the risk of slag arrival to the tuyeres. It further serves to optimize the tapping parameters, such as the drill bit diameter and the clay mass compound, by analyzing how the taphole throughput and diameter evolves during tapping. Compared to mass-balance models, only few parameters need to be known, for instance, there is no need for taphole parameters, the slag arrival time or the coke voidage. Compared to EMF methods, the strain method is not depending on the hot metal temperature, the measurements are considerably more stable, and the level of both liquids are measured.