Dissection investigation of blast furnace hearth-Kokura No.2 blast furnace (2nd campaign)

Dissection investigation of blast furnace hearth was made at Kokura No.2 Blast Furnace (2nd Campaign). Before blow-out, tracer response test was carried out in order to estimate the molten iron flow in hearth, and the measured data indicated that the depth of 'effective' flow region of molten iron was extremely shallow. According to the result of the dissection investigation, the deadman was floating in hearth, and deadman coke was considerably degraded. Therefore, the poor permeability of the deadman is supposed to cause a downsize in the flow space of molten iron, which coincides with the prediction through the tracer response test. The numerical method to estimate the boundary shape of the deadman was developed by means of evaluating the stress field of the deadman in hearth. The calculated result was in reasonable agreement with the observed shape of deadman. In addition, based on the data obtained by analyses of the boring samples, the thermal equilibrium erosion shape of hearth refractory was evaluated by numerical simulation, and a good agreement to the observed shape was found.