Criterion for crack initiation during drying: Alumina porous ceramic strength improvement

Improvement in the mechanical strength of the supports of porous catalysts is increasingly needed by the refining industry because of the high stresses induced by the exploitation of catalysts. Drying is known to be a critical process for mechanical strength during the preparation of supports, leading to micro-cracks in the case of hard drying conditions. In order to predict failure during drying, a crack initiation criterion, combined with a drying induced elastic stress simulation is proposed. Model parameters are the thermo–hydro–mechanical properties of the gel and the criterion is based on the tensile strength of an alumina gel at various moisture contents. The developed tool gives good results and can be easily adapted to several gel formulations as only effective properties of the gel are required. Drying is known to be a critical process for mechanical strength during the preparation of supports of porous catalysts, leading to micro-cracks in the case of hard drying conditions. In order to predict failure during drying, a crack initiation criterion, combined with a drying induced elastic stress simulation is proposed. The criterion is based on the tensile strength at various moisture contents. [Display omitted]