A transient method for the study of wetting in a liquid-liquid contactor
β Scribed by A. Mate; J. Morchain; O. Masbernat; C. Gourdon
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 895 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0009-2509
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β¦ Synopsis
The influence of packing material wettability on the dispersion transient flow in a disc and doughnut pulsed column has been studied. The outlet flow rate of the dispersed organic phase has been measured vs time until steady-state is reached (outlet flow rate equals inlet flow rate). Experiments have been carried out with two types of packing materials, namely stainless steel (non-wetting) and PTFE (wetting). Comparisions and integral analysis of the results exhibit the effect of toluene wettability on the dispersion residence time with a PTFE packing. Considering the fact that no redispersion of the wetting film occurs, it is possible to derive the volume of toluene wetting the PTFE packing during the column filling. Two major effects are observed: on the one hand, the wetting process generates an apparent delay in the outlet flow rate curve obtained with PTFE plates compared to that obtained with stainless-steel plates (transient regime). On the other hand, the slope of the outlet flow rate is decreasing as the output flow rate value tends toward the inlet flow rate (steady state). The first effect is due to drop-plate coalescence, whereas the second effect has been identified as drop-wetting film coalescence. From the experimental outlet flow rate curves and observations, a wetting process model has been postulated to predict the wetting phase flow rate as the column is filled with the dispersed phase. The main parameters of the model are the wetting coefficient kw and the volumetric fraction of the wetting phase ~w. The fitting of these parameters with experimental results reveals that the wetting rate of the drop-plate coalescence (transient regime) is two orders of magnitude larger than the drop-film coalescence rate (steady state).
π SIMILAR VOLUMES
## Abstract Sauter mean drop sizes (__d__~32~) generated from a hole distributor in liquid extraction RDC columns were studied under various conditions. Experiments were designed to generate data required to determine the main variables that control the drop sizes in RDCs. Two precise correlations
The mechamsm of spreadmg of a drop on a smooth sohd surface IS dscussed and the role of surface vlscoslty m the dynamics of the process stressed The wettmg force produces a velocity gradlent along the free interface via the surface vlscoslty This motion IS transferred via the bulk vlscoslty to the b