Mass and heat transfer from drops in liquid‐liquid extraction

Abstract

Mass and heat transfer rates in extraction are studied theoretically and experimentally for the practical range of the variables involved. For the particular but typical case of liquid drops moving through another liquid a simple correlation for the over-211 mass transfer coefficient is presented, which holds with a probable error of 20%.Included are systems in which the rate is limited by either coefficient, as well as systems in which both coefficients are significant. The correlation, valid for both directions of transfer with either phase dispersed, is useful for the extrapolation of performance from system to system in a given piece of equipment. Also, together with correlations for transfer area and effective driving force, it is part of the information needed for design.

LLECMOD: A Bivariate Population Balance Simulation Tool for Pulsed Liquid-Liquid Extraction Columns

“…This approach has been criticized by several authors because of the missing physical basis. One reason is the interfacial instability that Handlos and Baron [53] have neglected the Marangoni effects. Marangoni effect was first observed in 1865, this effect is attributed to a change in surface tension.…”

“…In the LLECMOD simulation program different approaches to calculate the mass transfer coefficients for the droplets inside k d or k c outside droplets can be used. In addition to traditional approaches, such as Handlos and Baron [53], Kumar and Hartland [54] and Newman [55], more recent correlations or user-defined models are included.…”

LLECMOD: A Bivariate Population Balance Simulation Tool for Liquid- Liquid Extraction Columns

“…The relative error is less than 10%, with the exception of the dispersed phase concentration at the column exit. For this specific case, the correlation of Handlos and Baron [36] was used as a mass transfer mode assuming oscillating droplet behavior. Additionally, the correlation of the distribution coefficient according to Schmidt [26] was used.…”

“…In LLECMOD many available phenomenological and experimentally correlated mass transfer models are included [35][36][37][38][39][40][41]. Accordingly, the resistance in series combination of these individual mass transfer coefficients results in the overall mass transfer coefficient, K oy , which can be used to predict the rate of change of solute concentration in the liquid droplet as expressed in terms of the droplet volume average concentration:…”

“…(A14) and Tables A3 and A4. In the simulation of liquid-liquid extraction columns with standard chemical systems, the Newman [35] or Handlos and Baron [36] models could be chosen. In some cases were no solid theoretical models are available (e.g.…”