Solids repacking

Some geometric transport models are based on solid characteristics rather than on properties of the pore space itself. By assuming a particular packing arrangement it is possible to infer the pore space geometry from information on the size and shape of the solid particles (Coelho et al., 1997). While this approach may be applicable to sieved and repacked soil columns, it is often inappropriate for undisturbed samples, with pore characteristics that depend more on soil structure than on soil texture. Thus, models to predict solute dispersion from the properties of particles in packed beds (e.g., Aris Amundson, 1957 Koch Brady, 1985 Ras-muson, 1985) are not the main focus of this review. 

Movements, repacking, and regrouping of solid particles in a liquid phase... 

Ergun showed that Eq. (7,22) fitted data for spheres, cylinders, and crushed solids over a wide range of flow rates. He also varied the packing density for some materials to verify the (1 — e) /e terra for the viscous loss part of the equation and the (1 — s)/e term for the kinetic-energy part. Note that a small change in e has a very large effect on Ap, which makes it difficult to predict Ap accurately and to reproduce experimental values after a bed is repacked. 

The TS-PF-SSR can be a very productive instrument for the study of adsorption, as well as other fluid/solid interactions. In adsorption, because the solid sample needs to be reused, completely reversible systems are easiest to handle. If the solid samples need to be replaced after each run, more ingenious instrument designs may be required in order to automate the carrying out of a TS-PF-SSR experiment without stopping to repack the reactor after each run. Even without this level of automation, temperature scanning procedures applied to fluid/solid interactions are sure to increase productivity in the study of fluid/solid interaction kinetics. 

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