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

No abstract

No abstract

A laminar flow field in which the velocity profile may be distorted in a predictable manner was achieved in a 7-cm porous pipe with uniform wall injection over the ranges of variables: 0 5 I. 5 2, 200 S NRr S 800 and 0.05 5 X 5 0.2.

Gas holdup and pressure loss were measured for various gas-liquid systems in a batch, multistage bubble column. Experimental results show that the use of screen plates (a = 0.64) considerably increases the gas holdup but introduces a significant pressure loss for the two-phase mixture. The pressure loss was found to be independent of physical properties of the mixture, and predictable either from the modified separated flow model or from the kinetic energy loss based on the liquid circulation velocity. .--.__ -~ On a mesurC la retention de gaz et la perte de charge pour diffkrents systtmes gaz-liquide dans une colonne B bulles multi-etagees en rCgime discontinu. Les resultats expkrimentaux montrent que I'utilisation de plateaux B grilles (a = 0,64)augmente considtrablement la retention de gaz mais introduit une perte de charge importante pour le melange biphasique. II apparait que la perte de charge est independante des proprittks physiques du melange et qu'elle peut &re prtdite B partir du modtle d'dcoulement stpare modifik (Chen et coll., 1986) ou encore de la perte d'energie cinetique baste sur la vitesse de circulation du liquide.Keywords: multiplate bubble column, screen plates, bubble column, holdup, friction t has been reported (Schugerl et al., 1977;Shah et al.,