Flux Response Technology (FRT) Applied in Zero Length Column Diffusivity and Adsorption Measurements

Abstract

The adaptation of flux response technology (FRT) as a novel in situ perturbation technique in gas sorption measurements continues to yield consistent results with literature values. Earlier studies have successfully reported on the FRT-zero length column method of studying propane diffusivity within an alumina/CeZrOx washcoat as a function of temperature (Maguire et al. in Chem Eng Sci 87:224-233, 2013; Sasegbon and Hellgardt in Adsorption, 2012). This study details FRT's ability in quantifying and analysing the dynamic process of carbon dioxide (CO 2 ) adsorption on zeolites with varying Si/Al ratios as well as measurements of CO 2 diffusion coefficients without the need for running separate experiments. This is made possible because FRT measures miniscule changes in transient flows in the order of 10 −2 µl/min for gaseous processes involving a change in volume (dV /dt). These changes are measured directly by a very sensitive differential pressure transducer in a pneumatic system analogous to an electrical Wheatstone bridge assembly, whereby gas molecules replace electrons and capillaries function as resistors.