Gas—liquid solubility

In order to allow integration of countercurrent relations like Eq. (23-93), point values of the mass-transfer coefficients and equilibrium data are needed, over ranges of partial pressure and liquid-phase compositions. The same data are needed for the design of stirred tank performance. Then the conditions vary with time instead of position. Because of limited solubility, gas/liquid reactions in stirred tanks usually are operated in semibatch fashion, with the liquid phase charged at once, then the gas phase introduced gradually over a period of time. CSTR operation rarely is feasible with such systems. 

We see that there is a critical value of the Henry s law constant, HAfint = kG/kL, for which the gas- and liquid-phase resistances are equal. For HA <, HA crit (i.e., a slightly soluble gas), liquid-phase mass transport is controlling. If HA HA ml (i.e, a very soluble gas), gas-phase mass transport controls the deposition process, and the transport is independent of the value of HA. The two limiting cases are... 

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