The effect on the liquid-phase effective diffusivity in fine pores of the ratio of solute molecular diameter to pore diameter and of preferential solute adsorption was studied by measurements on homogeneous silicaalumina bead catalyst (pore diameter = 3.2 nm). A proposed empirical correlation is based on the investigation of a variety of binary systems of p a r f f i s and aromatic hydrocarbons and of aqueous solutions of sugars.
= dimensionless axial position o = frequency, rad./hr. 8 = time, hr. Su b r r i p t s g = gas phase in = gas phase inlet k 1 = liquid phase Coefficienh in Gas Phase Equations (17), (18). (191, and (23) 1 2 0 n ma = radial mesh point location = axial mesh point location A. -----2 0The hydrogenation of alpha-methylstyrene to cumene at 20 to 50°C. was studied experimentally with o trickle-bed reactor comprising a single vertical column of spherical porous palladium-on-alumina catalyst pellets. Other studies with powdered catalyst and studies in which catalyst pellets were swirled in a reactor allowed the intrinsic kinetics and effectiveness factor of the catalyst pellets to be determined. A t 50°C. the reaction rate in the trickle-bed was about one-half of that in the absence of mass transfer limitations in the outside liquid film. The effectiveness factor of the pellets alone at 50°C. was 0.0057, and the tortuosity factor was 7.5. Experimental results are compared with four theoreticol models for tricklebed reactors and criteria are presented for estimating whether mass transfer through the outside film is a significant resistance in an industrial trickle-bed reactor.A trickle-bed reactor consists of a fixed catalyst bed in the bulk gas phase and the liquid-gas interface, ( b ) mass which the liquid reactant flows over the catalyst pellets transfer through the liquid film surrounding the pellets, while the reacting gas, which fills the voids, flows either (c) diffusion and simultaneous reaction within the liquidin the same or opposite direction. The rate-controlling step filled catalyst pores, and ( d ) intrinsic kinetics of reaction can be one or a combination of the following processes: at the catalyst surface. The object of this study was to (a) mass transfer of reactants and/or products between determine the role played in the performance of a trickle-
Measurements of diffusion and partitioning of nearly monodisperse polystyrene, having molecular weights of from 600 to 670,000, in chloro‐form and dichloroethane and of two proteins in aqueous solution were made with leached borosilicate glass cubes having a narrow pore size distribution and pore radi of from 2.5 to 47.6 nm. With increasing ratio of molecular to pore size, the partition coefficient for all solutes decreased; the ratio of effective to bulk diffusivity decreased for the proteins but remained constant for polystyrene. This suggests that polystyrene behaved like a free‐draining macromolecule under the conditions of this study.
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