Separation of surface and bulk phase diffusivities: A kinetic theory analysis

✍ Scribed by Lynn J. Groome; George Pothering

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 669 KB
• Volume: 34
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(79)85148-9

✦ Synopsis

kmetrc model for the effective (eg surface plus bulk) dtffuswrty In a porous bed composed of rectangular channels IS presented The ment of this approach 1s that no dlstmctlon IS made between the bulk and adsorbed phase and the effective axml flux can therefore he compared directly with expenmental measurements We utihze the elements of the BGK kmetic equation and express D d as an explicit function of the surface potenhal and colhsron frequency Detmls concemmg gas-gas collts~on dynamics and gas-sohd mteractlons are contamed m the relaxahon time. r, and the external force, F,, respecttvely For definiteness. the analysis IS Imuted to hard sphere gas-gas colhoons, although no special significance IS rmphed by this choice The assumption of a dtscontmuous gas-solid mteractlon potentral results m a separation of the form with Interactive modification of both D. and D, Prehmmary calculations Indicate that only when Kw IS large wdl surface diffusion become a slgndicant &de of transport