Effects of porosity and pore size distribution on mechanical strength reliability of industrial-scale catalyst during preparation and catalytic test steps

This paper investigates the effects of porosity and pore size distribution on crushing strength reliability of industrial-scale catalysts during their preparation and after reactor tests. Six supports, fabricated from two types of gamma-alumina (type A, 119 m(2)/g; and type B, 343 m(2)/g), were used as starting materials. The supports were impregnated using a copper/zinc nitrate solution. The supports and catalysts, before and after the reactor tests, were characterized using XRD, ICP, SEM, and BET methods and were subjected to single particle crushing strength tests. The results revealed that the strength and Weibull modulus of all samples were decreased after the impregnation process due to the emergence of new flaws. In contrast, the partial sintering/necking of the interparticles during the reaction led to an increase of the crushing strength of the used catalysts. Furthermore, the porosity of the supports and catalysts from type A to type B gamma-alumina were increased, leading to the strength decrease. Nevertheless, their Weibull modulus and strength reliability were increased due to the narrowing of pore size distribution in the range of mesopores.