Dispersion in non-ideal packed beds

Authors

  • U. M. Scheven

    Corresponding author
    1. REQUIMTE/CQFB, Departamento de Química, FCT-Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
    • REQUIMTE/CQFB, Departamento de Química, FCT-Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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Abstract

This work reanalyzes published time series dispersion traces (Han et al., AIChE J. 1985;31:277–288) from step input tracer passages recorded at different locations along the length of a packed bed filled with monodisperse solid spheres. The intrinsic dispersivity and sample dependent dispersion are separated by imposing a heuristic model where coarse grained axial advection velocities vary in a plane perpendicular to the flow but not along the direction of flow. The derived intrinsic dispersivity agrees with the predicted value (Scheven et al., Phys Rev Lett. 2007;99:054502-1–054502-4). It serves as a bench mark for different implementations of simulations coupling Stokes flow and diffusion in random geometries, and for experimental tests of injection and packing methods. Conceptually, a well defined and fittable effective dispersivity is introduced in an analytical framework describing dispersion data obtained in non-ideal packed beds, where elution profiles cannot be fitted to the solution of the one dimensional advection diffusion equation. © 2009 American Institute of Chemical Engineers AIChE J, 2010

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