Diffusion is the transport of material due to concentration gradients, or more precisely due to gradients in the chemical potential. Mass transfer is commonly described as diffusional phenomena in the presence of convective motion. Diffusion and mass transfer play a significant role in several materials processing operations. Diffusion and mass transfer are also of crucial importance in affecting the structure of solid products including segregation phenomena in castings and impurity distribution in crystal growth [1]. Inverse gas chromatography (iGC) can be applied to determine the diffusion coefficients for a wide range of vapors with various solids over a broad temperature range. iGC is generally considered an appropriate tool for measuring transport diffusion, since the experiments are performed in a flowing system and under concentration gradients. According to these considerations, iGC appears to be an appropriate method for diffusion investigations on FCC catalysts because it is a transport diffusion type measurement simulating to a certain degree diffusion in an actual FCC reaction zone.

Inverse Gas Chromatography Surface Energy Analyzer (IGC-SEA) was used to determine the diffusion coefficient of two different organic probes for two catalysis samples and the natural graphite at different temperatures in order to see the temperature effect on the diffusion of the different probes. During the webinar these results will be demonstrated and the principle of the analysis.