Prediction of permeation behavior of CO2 and CH4 through silicalite-1 membranes in single-component or binary mixture systems using occupancy-dependent Maxwell–Stefan diffusivities
✍ Scribed by Sang Cheol Lee
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 882 KB
- Volume
- 306
- Category
- Article
- ISSN
- 0376-7388
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✦ Synopsis
Permeation behavior of CO 2 and/or CH 4 through silicalite-1 membranes without support in single-component or binary mixture systems at 298 K was theoretically investigated using occupancy-dependent Maxwell-Stefan (M-S) diffusivities. The M-S surface diffusivity calculated from quasi-chemical theory, which describes occupancy-dependent diffusion more accurately, was compared with those based on weak and strong confinement scenarios in single-component systems. The calculated M-S surface diffusivities of CO 2 and CH 4 from the quasi-chemical approach were close to those from the strong confinement scenario for CO 2 and the weak confinement scenario for CH 4 , respectively. However, there existed some differences in permeation behavior between the quasi-chemical approach and the scenarios, especially at a high pressure. With the quasi-chemical approach, permeation behavior of each species in CO 2 /CH 4 mixture systems was investigated using three different M-S exchange diffusivities related to correlation effect. The magnitude of M-S exchange diffusivity had a little influence on permeation behavior of the slower and more strongly adsorbed CO 2 , while it produced a big difference in transient flux and occupancy profile for the faster and most weakly adsorbed CH 4 .