The hydrodynamics of a 5-cm reciprocating-plate Karr column used for cocurrent gas-liquid contact were studied over the ranges 0 < AF < 10 cm/s, 0 < VL < 6 cm/s, and 0 < Vg < 14.3 cm/s. The frictional loss is closely related to the liquid circulation within the column. The plate reciprocation shows little influence on the gas holdup until it reaches a critical value. The column can generate bubbles of average diameter between 3 and 6 mm and an interfacial area approximately 3 times that found in bubble columns under otherwise the same operating conditions.

Gas holdup and pressure drop measurements were made in two multistage bubble columns. Plates made from 6 mesh/in screen (a = 0.64) and those of Karr design (a = 0.53) were tested. An improved separated-flow model was developed for correlating the two-phase friction losses over the ranges: 0 C V, C 8.22 cm/s and 0 C V L 6 6.12 cm/s. This model was also sound for the vibrating disk column introduced by Tojo et al. (1974).Empirical correlations are presented for the gas holdup and the pressure drop due to liquid circulation within these two columns.Des mesures de rktention des gaz et de perte de charge ont CtC effectutes dans deux colonnes a bulles a Ctages multiples. Des plateaux faits d'un tamis de 6 mailles/po (a = 0.64) et des plateaux de type Karr (a = 033) ont CtC testes. Un modkle amCliore avec stparation des Ccoulements a ete Ctabli pour exprimer les pertes par friction d'un Ccoulement biphasique sur les gammes suivantes: 0 6,12 cm/s. Ce modtle s'est Cgalement avCrC applicable pour la colonne a disques vibrCs proposCe par Tojo et al. (1974).Des corrklations empiriques sont presentees pour la ritention des gaz et la perte de charge causCes par la circulation liquide a I'intCrieur des deux colonnes. V,8,22 cm/s et 0 G V, he bubble column is a relatively simple and economical

The axial mixing and mass-transfer characteristics of a Karr column when used as a cocurrent, gas-liquid contactor were experimentally determined. The liquid-phase backmixlng is extremely small, and the plug flow can be safely assumed in this column over the ranges 0.6 cm/s < VL < 4.34 cm/s, 0.7 cm/s < Vg < 5 cm/s, and 1.8 cm/s < AF < 7.5 cm/s. Over the same ranges, the liquid-side volumetric mass-transfer coefficient kLa was found to increase significantly with an increasing liquid velocity, gas velocity, or speed of plate reciprocation. The effect of the liquid flow rate is particularly strong because of its simultaneous, favorable influence on the liquid-side coefficient kL and the interfacial area a. Both the speed of plate reciprocation and the gas flow rate were found to have a highly adverse effect on kL. Satisfactory correlations of kLa and of kL based on the liquid velocity at the orifices of the plates are presented.

The kinetics of the reaction of oxygen with sodium sulphite in aqueous solution without and with a catalyst of cobaltous sulphate have been studied by a flow thermal method. The rate of reaction of oxygen and sodium sulphite was found to be first‐order with respect to oxygen and variable order with respect to sulphite, and the promoting effect of cobaltous catalyst was proportional to its concentration. A reaction mechanism has been proposed and a rate expression derived which is in good agreement with the experimental data.

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