Experimental and numerical analyses of thermomechanical refractory lining behaviour

Abstract

Refractory linings are used in order to protect the steel structure in industrial applications such as coal-fired power plants or steel ladles. These linings are subjected to important thermal loading that can lead to cracking (due to the difference between the thermal expansion of steel and the thermal expansion of the refractory). The aim of this study is to build a tool that allows the structural design to be improved so as to decrease the refractory cracking. The first approach is developed on a local scale. A special furnace allows the reproduction of the thermal conditions in a coal-fired plant. Acoustic emission is employed to detect when the refractory is cracking. A finite element analysis, using three-dimensional elements and a smeared-crack model, is conducted to reproduce the experimental observations. The material behaviour is identified using an inverse method. This local approach can be directly used for structural analyses when the geometry of the lining is sufficiently simple. For instance, the computation of a steel ladle is presented. When the geometry of the lining is very complex, it is not possible to compute it with this three-dimensional model. In this case, a simplified approach using a two-layered composite shell, the behaviour of which is equivalent to the three-dimensional behaviour, is briefly described.