Liquid-wall mass transfer in three phase fluidized beds with cross-flow of electrolyte

Mass transfer at the confining wall of helically coiled circular tubes with gas–liquid flow and fluidized beds

“…Jagannadha Raju and Rao [17] in their studies on wall-to-bed mass transfer in fluidized beds observed that the mass transfer coefficient at the electrode surface increased with increase in particle diameter. Similar observations were also made by Ramesh et al [18,19] in three-phase fluidized beds. To investigate the effect of particle diameter on k L in the coiled flow, data were obtained with sand of two different sizes of 0.5 and 1.0 mm as bed material.…”

“…Yasunishi et al [20] observed that the wall-liquid mass transfer coefficient was largely influenced by gas velocity and relatively independent of liquid velocity in gas-liquid up flow bubble columns. Ramesh et al [18,19] reported that the effect of liquid velocity on wall-to-bed mass transfer coefficient was insignificant in three-phase fluidized beds when the liquid velocity was varied over a moderate range. With these observations, one can anticipate that even in the helical coils the effect of liquid velocity would be marginal on wall-liquid mass transfer coefficient in case of two-phase flow.…”

Wall-to-bed mass transfer in three-phase fluidized beds in the absence and presence of a composite promoter

“…Effect of gas velocity: variation of mass transfer coefficient with superficial liquid velocity in the absence of promoter for particle dia of 3.13 mm. Ramesh et al [4] in wall-to-bed mass transfer studies in annular flow.…”

“…The introduction of a gas into a liquid-solid fluidized bed was found to be advantageous as it enhances turbulence resulting in increased mass transfer as discussed elsewhere [2,3]. Further, when a helicoidal tape promoter is inserted in a threephase fluidized bed, swirl flow may be visualized and the swirl generated due to the flow of the fluid past the boundaries of the helical tape element induces its radial component into the axial flow.…”

“…It was observed that the wall-to-bed mass transfer rates could be significantly increased by introducing the gas-phase into a two-phase liquid-solid fluidized or packed bed because of agitation or turbulence promoted by the gas-phase. Very few studies [1][2][3][4][5] have been reported on wall-to-bed mass transfer in three-phase fluidized beds. It is well known that overall mass transfer rates can be augmented by the presence of turbulence promoters or circulating solids of inert particles.…”