Phase holdup characteristics of three phase fluidized beds

Authors


Abstract

The individual phase holdups in two (liquid-air, liquid-solids) and three (liquid-air-solids) phase fluidized beds have been measured over a wide range of liquid and gas velocities. Ex-periments were canied out in a large two-dimensional bed. Three solids were used ranging in size from 1 to 6 mm.

The effect of viscosity (1-70 cp) was determined using solutions of sugar and carboxymethyl cellulose of different concentrations. Various acetone-water mixtures were employed to examine the effect of surface tension in the range 40-73 dyne/cm.

Beds of particles having a minimum fluidizing velocity in the liquid of less than 1.28 cm/sec were found to initially contract upon the injection of gas. In contrast, beds of particles having minimum fluidizing velocities exceeding tins value were found to expand.

Abstract

On a mesuré, sur line graiide échelle de vitesses de liqnides et de gaz, les retentions dans chaque phase dans le cas de lits fluididsés B deux phases (liquide et air) et B trois phases (liquide, air et solides). On a fait les expkrimces dans un lit considkrable B deux dimensions. On a employ6 trois solides doiit la grosseur des particules variait entre 1 et 6 millimktres.

On a dkerminC l'effet de la viscositk (1 à 70 centipoises) au nioyen de sucre et de cellulose carboxymkhylCe de diffkreiitcs concentrations. On a utilisk divers niClanges d'acktone et d'eaii pour examiner I'effet de la tension superficielle pour une kchelle de 40 A 73 dynes par centimktre.

On a constate que, lorsqu'on injectait du gaz, il y avait unc contraction initiale des lits formks de particules dont la vitessc fluidisante niiiiimale dam le liquide Ctait infkrieure B 1.28 centimktres A la seconde, tandis qn'il y avait expansion desdits lits lorsque la vitesse en question exckdait 1.28 centimhtres h la seconde.

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