Interpretation of Tap Induced Cyclic Temperatures in the Blast Furnace Lining

The thermal behavior of the blast furnace hearth was studied using modeling. The focus was the effect of the size and shape of the taphole clay layer around the taphole. Four different cases have been calculated: one reference case and three cases with different taphole clay layer geometries. It was found that the calculated peak‐to‐peak amplitudes of the lining temperatures during the tap cycles at the location of a thermocouple can be approximated as a linear function of the taphole clay layer thicknesses for all calculated cases. Modeling was also done where both the 90th and the 10th percentile of the observed peak‐to‐peak values of the studied tap cycles were included to describe the behavior of the operating furnace. The taphole region can be divided into three categories based on how well the model can describe the measured process data: below, at, and above taphole level. Below the taphole level, the measured lining temperature variations are smaller than for the calculated results. At the taphole level, the model can describe the behavior well. Above the taphole level the measured lining temperature variations are larger than for the calculated results. It was concluded that in order to make a more accurate heat transfer model of the taphole region, the presence of a skull build‐up below the taphole, erosion above the taphole, and the bath level variations need to be taken into account.