The influence of the textural properties of aluminum foams as catalyst carriers for water gas shift process

Abstract

Aluminum foam based structured catalysts were prepared and tested for the CO water gas shift reaction, and the influence of the textural properties of the carriers, over the performances, were evaluated. An estimation of the kinetic parameters, by applying the Langmuir–Hinshelwood model, was also provided. Three aluminum foams with different porosity were used in the preparation of the catalysts; the carriers were previously washcoated with an alumina-based slurry, subsequently, the support and the active component, were loaded by impregnation with an aqueous solution of the precursor salts. The good stability of the structured catalysts to the mechanical stress, was demonstrated with the results of the ultrasonic adhesion test. The results of the activity tests showed no direct correlation between the porosity of the carriers and the performance of the catalysts, suggesting the occurrence of other phenomena. The estimation of the effective thermal conductivity of the three aluminum foams indicated a clear correlation between CO conversion and thermal conductivity of the carriers, highlighting the effect of the redistribution of the generated heat of reaction along the catalytic bed, on the performance of the catalyst. However, the direct dependence of the thermal conductivity of the foams from the thickness of the intersection between the fibers, was recently demonstrated, confirming the dependence of the performance of these catalysts from the textural properties of the carriers.