Effect of Turbulence on the Separation of Liquid−Liquid Dispersions in Batch Settlers of Different Geometries

Abstract

The separation of batch dispersions is affected by the initial turbulence present in the settler which reduces the initial sedimentation rate and the onset of interfacial coalescence. As the turbulence decays, these rates gradually increase, giving rise to sigmoidal sedimentation and coalescence profiles. A model is presented which describes the separation of a dispersion of height H 0 and holdup ε0 with an initial drop diameter φ0, and interfacial coalescence time τd allowing for the turbulence decay time t d and coalescence incubation time t 0. For a given holdup ε0, the drop diameter φ0 and initial turbulence are themselves functions of the mixing conditions. The model is used to describe experimental data for both water-in-oil and oil-in-water dispersions for different liquid−liquid systems ranging from a heavy crude to a water-like model oil. The effect of physical properties, holdup, initial turbulence, and settler geometry is investigated.

Estudio de separación de fases en sistemas líquido-líquido usando LIX 984N en fase orgánica

“…Industrialmente es importante conocer los tiempos de separación de fases, determinar los arrastres, así como la distribución de tamaño de las gotas de la mezcla o un tamaño característico de la dispersión, tal como el diámetro de Sauter (d 32 ). La sedimentación y coalescencia dependen de un gran número de factores tales como: concentración de la fase dispersa, propiedades físicas, geometría del mixer-settler, turbulencia, presencia de sustancias tensoactivas e incluso presencia de partículas finas [7][8][9] .…”

Sedimentation and Coalescence Profiles in Liquid‐Liquid Batch Settling Experiments

“…Good agreement was obtained between experimental results and the model prediction. Furthermore, the effect of the initial turbulence on the separation of batch dispersion was considered and verified with experimental data [5]. Based on the fundamental results of Jeelani and Hartland [4], Henschke et al [6] presented a new model to describe the coalescence process with a single integral coalescence parameter obtained from a batch settling experiment.…”

Monitoring and Modeling of Creaming in Oil-in-Water Emulsions

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