PFG NMR measurements of tortuosity factors for diffusion in meso- and macropores of FCC catalysts
نویسندگان
چکیده
Pulsed field gradient (PFG) NMR is applied to measure self-diffusion coefficients of 1,3,5 triisopropyl-benzene in the particles of several industrial FCC catalysts having different systems of mesoand macropores. Relating these diffusivities to the self-diffusion coefficient of 1,3,5 tri-isopropyl-benzene in the liquid phase, the tortuosity factors for diffusion in the mesoand macropores of the particles were obtained. The values of the tortuosity factors were found to increase with a increasing volumetric fraction of the small (< 20 nm) mesoand macropores in the total intraparticle volume.
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