FEM simulation of the thermomechanical behaviour of the refractory lining of a blast furnace

Ceramic refractory materials are applied for the lining of industrial furnaces including vessels of the steel industry, where refractories are exposed to high temperatures as well as chemical and mechanical load. This paper reports experiences obtained with the thermomechanical FEM modelling of the refractory lining of a blast furnace. The lining of the furnace consists of several layers of different materials; layers of shaped refractories (bricks) are combined with layers of unshaped (monolithic) products. To account for the complex nature of thermomechanical behaviour of refractories a wide range of non-linear material laws, such as tensile cracking with strain-softening and hydrostatic pressure sensitive plastic failure, has been used in the model. The mechanical properties applied were taken as temperature dependent. The thermomechanical behaviour of some unshaped products is particularly complex. At room temperature the mechanical behaviour has many similarities with that of unconsolidated sand, but with rising temperatures due to a wide range of possible chemical and physical processes the material may stiffen. A special approach to model the monolithic refractories has been developed. The simulation was applied to investigate the response of the lining to the thermomechanical service loads and the interaction between the layers of the lining. The results can be used to optimise the lining design and the choice of material.