Measuring Methods for Lining Erosion of the Blast Furnace

Abstract

A new fine multiple thermocouple sensor (FMT sensor) for the measurement of refractory lining erosion of a blast furnace is presented. In the newly developed sensor, the temperature sensing parts of several sheathed thermocouples are arranged longitudinally parallel. They are accommodated in an external sheathing tube in such a manner that these thermocouples are prevented from coming into mutual contact by means of insulating refractory materials. The sensor can simultaneously measure the temperature variations at several positions in the refractory lining.A method of analyzing the FMT signals (The Trigger Response Method) has also been developed for calculating the remaining thickness of refractory lining in the shaft of a blast furnace by analyzing the time-delay occurring in the propagation of temperature variations in the lining. By applying this method to 19 months of field testing in the shaft of No. 1 Blast Furnace of Kobe Works, it was possible to estimate the extent of erosion of the refractory lining within an error tolerance of less than 5%.A method of analyzing the temperature distribution in the lining (The Profile Coefficient Method) has also been developed for estimating the profile of lining erosion in the hearth by introducing the Profile Coefficient defined by the solution of the finite element method in which the boundary conditions are determined indirectly by using measured temperatures in the lining. This method was applied in the No. 1 Blast Furnace of KakogawaWorks and its practicability was confirmed when its estimation corresponded to those taken by the dissection studies.