Detection and Quantification of the Dead Man Floating State in the Blast Furnace

The lower part, the hearth, is a crucial region of the ironmaking blast furnace. The life length of it often determines the campaign length of the furnace and the thermal state and permeability of the hearth exert strong influence on liquids drainage and hot metal chemistry. In order to operate the furnace efficiently, the hearth state should be controlled, but the conditions in the hearth are extremely hostile with little possibility to carry out direct measurements. This article presents a set of methods and models through which the floating of the hearth coke bed, the dead man, can be assessed. Data from three industrial blast furnaces illustrate how a systematic analysis of available measurements, in combination with results of mathematical models of the phenomena in the hearth, can successfully detect and quantify the dead man floating state.