Dilution of catalyst in a fluidized bed. Dehydration of ethanol

Abstract

I 5 6 7 3 9 1 0 1 1 !2 Catalyst loaalng x 10' 4 gm mi-' Figure 3. Effect of catalyst loading on reaction rate. expression (Table 111). A few experiments were also done varying the initial concentration of o-nitroaniline and the values of the specific reaction rate were observed to be essentially constant. Thus it appears that the kinetic data could be correlated by an empirical rate expression: r = Effect of Temperature. The temperature of the reaction was varied from 47 to 74 "C. The rate of the reaction increased significantly with the increase in temperature. The apparent activation energy was found to be 13.0 kcal/mol (Figure 2). kCN COMMUNICATIONSEffect of Catalyst Loading. The catalyst loading was varied from 0.484 to 1.21 g/L at 69 "C, keeping the initial concentration of o-nitroaniline and hydrogen partial pressure at 0.701 M and 961.1 kN/m2, respectively ( Figure 3). As expected, the reaction rate was found to increase linearly with the catalyst loading. AcknowledgmentOne of the authors (P.B.K) would like to thank University Grants Commission for award of a research fellowship. Nomenclature CN = concentration of o-nitroaniline, mol/mL k = rate constant, s-l r = rate of reaction, mol/mL s I = fraction of o-nitroaniline converted into o-phenylenedi- Literature CitedAcres, G. The dehydration of ethanol over alumina is studied in an integral(plug flow) and undiluted and diluted fluid bed reactors. At any given conversion level the Selectivity of the intermediate (ether) is always higher for the plug flow reactor than for the fluid bed reactor. Catalyst dilution in the fluid bed keeping residence time unaltered is seen to result in an increase in the formation of intermediate ether without a majar fall in overall conversion. Thus dilution of catalyst results in an improvement in the selectivity of intermediate without affecting the other useful features of fluid bed operation. An optimum catalyst dilution R' (mass of catalyst in the undiluted bed/mass of catalyst in the diluted bed) = 3.67 is shown to exist for the parameter values employed, such that intermediate formation at the bed exit is maximum.

Performance Enhancement of Steam Methane Reforming Using Tubular Packed-Bed Microreactors and Dilution by Adsorbent

“…The strategy of dilution by solids has been studied to improve packed-bed reactor performance and is now being increasingly applied. − ,− The cost of catalyst forms a major component in reactor operation, and dilution can help in this aspect. In addition to packed-bed catalytic reactors, catalyst dilution by solids has been applied to fluidized-bed reactors , and trickle-bed reactors. , Care should be taken, however, to prevent bypass of flow inside a reactor while employing the dilution strategy. − Catalyst dilution studies reported in the literature use inert solid−catalyst mixtures. In the present study, we assume that the catalyst is diluted with an adsorbent that acts not only as a diluent for the catalyst but also at the same time as an adsorbent for CO 2 .…”

“…[17][18][19][28][29][30][31] The cost of catalyst forms a major component in reactor operation, and dilution can help in this aspect. In addition to packed-bed catalytic reactors, catalyst dilution by solids has been applied to fluidized-bed reactors 32,33 and tricklebed reactors. 34,35 Care should be taken, however, to prevent bypass of flow inside a reactor while employing the dilution strategy.…”