A new method for the on-line monitoring of lining erosion in the blast furnace is presented. This method consists of a fine multiple thermo sensor and a data analysis program which is stored in the computer. The analysis program contains two theoretical models for the estimation of lining erosion in the last furnace. These theoretical models are named the "Trigger Response Method" and the "Profile Coefficient Method" respectively. The Trigger Response Method is applied to the shaft, belly and bosh portion of the furnace. The remaining lining thickness is calculated by analysing time-delays occurring in the propagation of temperature variations at multiple positions in the lining. The Profile Coefficient Method is applied to the hearth portion of the furnace where the remaining lining thickness is calculated by a simplified linear algorithm derived from solving PDE for heat tranfser. These methods have been used in several blast furnaces in Kobe Steel Ltd, and the extension of the lining erosion was observed dynamically from the initial state of furnace operation.
