Mass transfer in fixed beds

Experimental results for fixed packed beds are very sensitive to the structure of the bed which may be strongly influenced by its method of formation. GUPTA and Thodos157 have studied both heat transfer and mass transfer in fixed beds and have shown that the results for both processes may be correlated by similar equations based on. / -factors (see Section 10.8.1). Re-arrangement of the terms in the mass transfer equation, permits the results for the Sherwood number (Sh1) to be expressed as a function of the Reynolds (Re,) and Schmidt numbers (Sc) ... 

Zaiat, M., Vieira, L.G.T., and Foresti, E., Liquid-phase mass transfer in fixed-bed of polyurethane foam matrices containing immobilized anaerobic sludge, Biotechnol. Tech. 1996 vol. 10, no. 2, pp. 121-126. 

Hydrodynamics and mass transfer in fixed-bed gas-liquid-solid reactors operating at high pressure... 

When we started selling molecular sieves, little was known about heat and mass transfer in fixed bed adsorption/desorption. Design was an art. G.J. Griesmer, J.J. Collins, F.W.Leavitt, W.F. Avery, and K. Kiyonaga made it a science, a unit process we understand and can optimize. Griesmer led much of this activity and was primarily responsible for Union Carbide s Iso Sieve process for separating normal from iso paraffins [37]. 

D. Measuring Chemical Composition and Mass Transfer in Fixed-Bed Reactors In Situ Studies of Reactions... 

Carbary J. L(1960f) A boundaty-taya model of fluid-particle mass transfer in fixed bed. AIChE J, 6,460463... 

J. J. Carberry, A Boundary Layer Model of Fluid Particle Mass Transfer in Fixed Beds, A. I. Ch. E. Journal, 6,460 (1960). 

Interstitial mass transfer in fixed beds is frequently a significant factor in adsorption dynamics. Sherwood et al. (1975) developed an equation for both gases and liquids that employs the Colbum-Chilton y-factor ... 

RATE OF MASS TRANSFER. Equations for mass transfer in fixed-bed adsorption are obtained by making a solute material balance for a section dL of the bed, as shown in Fig. 25.8. The rate of accumulation in the fluid and in the solid is the difference between input and output flows. The. change in superficial velocity is neglected ... 

Mass Transfer in Fixed Beds of Porous Sorbents... 

MASS TRANSFER IN FIXED BEDS OF POROUS SORBENTS... 

A significant amount of research has been performed on the measurement of liquid-solid mass transfer [67], Generally, liquid-solid mass transfer in fixed-bed reactors has been studied by five methods dissolution of slightly soluble solids into the liquid [68-73], chemical reaction with significant liquid-solid mass transfer resistance [74], ion exchange followed by an instantaneous irreversible reaction [75], dynamic absorption [76], and electrochemical technique [77-80]. The electrochemical method has certain advantages over the other it facilitates direct and instantaneous measurements of solid-liquid mass transfer and is thus very useful to measure mass transfer fluctuations, especially under pulse flow conditions. 

Iliuta I, Thyrion FC. Gas-liquid mass transfer in fixed beds with two-phase cocurrent downflow gas/Newtonian and non-Newtonian liquid systems. Chem. Eng. Technol. 1997 20 538. 

Liang, S., and Weber, W.J., Parameter evaluation for modeling multicomponent mass transfer in fixed-bed adsorbers, Chem. Eng. Commun., 35(1), 49-65 (1985),... 

The role of external mass transfer resistance can be checked by the estimation of the Biot number and the mass transfer coefficient as described in Appendix 5. For experimental determination of the role of external mass transfer in fixed beds, a simple test is recommended the reaction is carried out in the fixed bed with different amounts of catalyst... 

Hirose, T.M., Y. Mori and Y. Sato, "Liquid-to-Particle Mass Transfer in Fixed Bed Reactor with Cocurrent Gas-Liquid Downflow", J, of Chem, Eng. Japan (1976) 220-224. 

Average transport coefficients for transfer between the bulk-fluid and particle surface can be correlated in terms of dimensionless groups that characterize the flow conditions. It is common practice to correlate experimental data in terms of y -factors. Usually, the mass transfer coefficient is obtained from the j factor for mass the heat transfer coefficient is obtained from j factor analogy. There have been many experimental studies of mass transfer in fixed-beds and summaries and analyses of the results are available (Whitaker 1972 Dwivedi and Upadhay 1977). For Reynolds numbers greater than 10, the following relationship (Dwivedi and Upadhay 1977) between jo and the Reynolds number represents available data ... 

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