Abstract
In our study on sub-critical hydrocarbon permeation in activated carbon, a minimum in the total permeability (BT) at low pressure has been observed for only long-chain hydrocarbons such asn-hexane andn-heptane. Such an observation suggests that the minimum appearance depends on the properties of permeating vapors as well as the porous medium. In this paper a permeation model is presented to explain the minimum behavior with the allowance of the collision-reflection factor in the Knudsen diffusivity to be a function of surface loading. Surface diffusion was found to be very significant compared to other transport mechanisms such as Knudsen diffusion and gaseous viscous flow at low pressures. Since the gaseous viscous flow contributes negligibly to the BT at low pressures, the minimum appearance in the BT is mainly attributed to the interplay between Knudsen diffusion and surface diffusion. Also, the molecular structure of adsorbates plays an important role in the minimum appearance.
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References
Adzumi, H.,“Studies on the Flow of Gaseous Mixtures through Capillaries: III. The Flow of Gaseous Mixtures at Medium Pressures,”Bull. Chem. Soc. Jap.,12(6), 292 (1937).
Bae, J.-S. and Do, D. D.,“Study on Diffusion and Flow of Benzene,n- hexane and CC14 in Activated Carbon by a Differential Permeation Method,”Chem. Eng. Sci.,57(15), 3013 (2002).
Carman, P. C, “Diffusion and Flow of Gases and Vapours through Micropores I. Slip Flow and Molecular Streaming,”Proc. Roy. Soc. (London),A203, 55 (1950).
Do, D. D., “Dynamics of a Semi-batch Adsorber with Constant Molar Supply Rate: A Method for Studying Adsorption Rate of Pure Gases,”Chem. Eng. Sci.,50, 549 (1995).
Do, D. D.,“A Model for Surface Diffusion of Ethane and Propane in Activated Carbon,”Chem. Eng. Sci.,51(17), 4145 (1996).
Do, H. D. and Do, D. D.,“A New Diffusion and Flow Theory for Activated Carbon from Low Pressure to Capillary Condensation Range,”Chemical Engineering Journal,84(3), 295 (2001).
Do, H. D., Do, D. D. and Prasetyo, I., “Surface Diffusion and Adsorption of Hydrocarbons in Activated Carbon,”AIChE J.,47(11), 2515 (2001).
Knudsen, M., “Die Gesetze der Molekularströmung und der inneren Reibungsströmung der Gase durch Röhren,”Annalen der Physik (Leipzig),28, 75(1909).
Mayfield, P. and Do, D. D., “Measurement of the Single Component Adsorption Kinetics of Ethane, Butane, and Pentane onto Activated Carbon using a Differential Adsorption Bed,”Ind. Eng. Chem. Res.,30, 1262(1991).
Moon, H., Park, H. C. and Lee, W. K., “Diffusional Interference in Liquid Phase Counter Adsorptions,”Korean J. Chem. Eng.,7, 250 (1990).
Pollard, W. G. and Present, R. D., “On Gaseous Self-diffusion in Long Capillary Tubes,”Phys. Rev.,73(7), 762 (1948).
Prasetyo, I., “Kinetics Characterization of Hydrocarbons on Activated Carbon with New Constant Molar Flow and Differential Permeation Techniques,” Ph.D., The University of Queensland, Brisbane, Australia (2000).
Schneider, P. and Smith, J., “Adsorption Rate Constant from Chromatography,”AIChE J.,14, 762 (1968).
Wicke, E. and Vollmer, W., “Flow of Gases through Micropores,”Chem. Eng. Sci.,1, 282 (1952).
Yasuda, Y, “Determination of Vapour Diffusion Coefficients in Zeolite by the Frequency Response Method,”J. Phys. Chem.,86, 1913 (1982).
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Bae, JS., Do, D.D. A unique behavior of sub-critical hydrocarbon permeability in activated carbon at low pressures. Korean J. Chem. Eng. 20, 1097–1102 (2003). https://doi.org/10.1007/BF02706943
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DOI: https://doi.org/10.1007/BF02706943