FEM investigation of global mechanisms affecting brick lining stability in a rotary kiln in cold state

Severe degradation of refractory lining in a rotary kiln often leads to very costly production delays. Use of finite element analysis for understanding the mechanisms behind the failure of the lining is poorly reported in this field. To increase the knowledge and to update the field a simplified model of a kiln and a new methodology for studying stability of the lining are suggested. Behaviour of the lining in cold state – in static and dynamic cases – is studied. Influence of ovality, brick's Young's modulus and friction coefficient on stress and brick displacement are evaluated at two rotational speeds. It was found that the induced loads in the lining are harmless regardless of the tested conditions — challenging the traditional beliefs. On the other hand, recorded brick displacements were found to be significantly affected by rotational speed and ovality. Gaps as large as 80 mm could be observed between the bricks and the casing in a worst case scenario. An integrity coefficient was defined in order to quantify overall integrity of the lining.