Measurement of transport rate coefficient in bidisperse porous catalyst by chromatography

Abstract

Chromatographic technique was used to determine parameters in the packed bed. When a pulse of the tracer was injected into a stream of carrier at the extrance of the packed bed, the time-dependent response peak at the outlet was obtained. The response peaks were measured by varing the carrier gas flow rate and the adsorbent particle size at different temperatures. From these response peaks, adsorption equilibrium constant, axial dispersion, macro- and micro-pore diffusivities were evaluated by means of the moment method. A bidisperse pore model, based upon no adsorption in the macropores and adsorption in the micropores, was employed to interpret the data. Results are obtained for the adsorption of cis-2-butene on Boehmite and carbon dioxide on $\gamma$-alumina. For cis-2-butene-Boehmite system, adsorption equilibrium constant is 104.93 $cm^3$/g at 75.3$^\circ$C and heat of adsorption is -8.91 kcal/gmole. Also, the macro- and micro-pore diffusivities at 75.3$^\circ$C were $1.06^*10^{-2}\,cm^2/\sec$ and $1.27^*10^{-5}\,cm^2/\sec$. For carbon dioxide-$\gamma$-alumina system, the adsorption equilibrium constants were measured as very small values. This characteristic of adsorption make it difficult to estimate other prarameters in the bed.