Correction for a possible reversible adsorption over an “inert” material

Abstract

All TAP micro-reactor configurations contain inert particles which are used so that the catalyst zone can be maintained under isothermal conditions. Even on “inert” particles adsorption will occur to some degree; however, the extent to which this occurs has a critical influence on the analysis of the TAP data. In many cases the assumption that there is no interaction between probe molecules and inert particles is required as reversible adsorption over inert material is problematic when the TAP model has to be solved. Moreover, as the TAP pulse response experiments are designed to be conducted within the Knudsen diffusion regime, central to TAP data analysis is the characterization of the diffusional transport of reagent molecules through the micro-reactor, which is achieved via “diffusion only” experiments over an inert one zone packing. Therefore, if there are any processes occurring in addition to Knudsen diffusion over the inert material, such as reversible adsorption, it is important to factor these into the analysis. If these additional processes are not included, the entire data analysis would be questionable. The current work discloses the development of a function which accounts for the adsorption over the inert material, so that the TAP data analysis can be accurately determined. This newly developed analysis method has been exemplified using the selective reduction of oxygen in a hydrogen rich ethylene feed over silver catalysts as a case study.