Modeling permeation of binary mixtures through zeolite membranes
- Delft Univ. of Technology (Netherlands)
The separation of ethane/methane and propane/methane mixtures with a silicalite-1 membrane was investigated as a function of composition, total hydrocarbon pressure (up to 425 kPa), and temperature (273--373 K). The selectivity of the membrane is highly dependent on these operating conditions. The generalized Maxwell-Stefan equations were used to predict the fluxes and the associated selectivities. These model predictions, based on separately determined single-component adsorption and diffusion parameters, were in excellent agreement with the experimental data. Using the empirical Vignes relation for the prediction of the binary Maxwell-Stefan surface diffusivity, there were no fitting parameters involved in the model prediction. The importance of incorporation of adsorbate-adsorbate interactions in the model is clearly shown, both for transient and steady-state mixture permeation. Theoretical analysis showed that for mixtures of a fast, weakly adsorbing component and a slow, strongly adsorbing component the maximum selectivity obtained with microporous membrane separation is always a factor of 2 lower than the one obtained under equilibrium adsorption conditions.
- OSTI ID:
- 346938
- Journal Information:
- AIChE Journal, Vol. 45, Issue 3; Other Information: PBD: Mar 1999
- Country of Publication:
- United States
- Language:
- English
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