Gas phase holdup

The experimental and theoretical work reported in the literature will be reviewed for each of the five major types of ga s-liquid-particle operation under the headings Mass transfer across gas-liquid interface mass transfer across liquid-solid interface holdup and axial dispersion of gas phase holdup and axial dispersion of liquid phase heat transfer reaction kinetics. 

This result can be useful for design purposes when the diffusivities, partition coefficients, feed-stream conditions, dispersed-system volume, gas-phase holdup (or average residence time), and the size distribution are known. When the size distribution is not known, but the Sauter-mean radius of the population is known, (293) can be approximated by... 

We can operate at the required liquid volume—say, by putting the reactor on load cells—but the gas-phase volume and thus the total volume may change upon scaleup. Correlations are needed for the gas-phase holdup and for kiAj. A typical correlation for kiAj is that by Middleton ... 

The liquid-phase reactions are valid for nitric acid concentrations below 34 wt %. In the case of higher nitric acid concentrations, Reactions (R5) to (R7) become reversible. The oxidation of NO (Reaction (Rl)) is the slowest reaction in this system. Therefore, the total gas-phase holdup in absorbers can be determined using the kinetic data for this reaction (130). The other gas-phase reactions are instantaneous equilibrium reactions. 

Henrys law constant for A and B, atm/(mol/volume) constants in equation (8-154) h gas phase holdup... 

Fig. 4. Typical normalized isotopic transient responses in product species P following an isotopic switch in reactant R— R. An inert tracer, I, is introduced to determine the gas-phase holdup of the reactor system.

Saxena SC, Rao NS, Thimmapuram PR. (1992) Gas phase holdup in slurry bubble eolumns for two- and three-phase systems. Chem. Eng. J., 49 151-159. 

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