The dynamics of extraction processes: Part I. Introduction and critical review of previous work

Abstract

A critical review and comparison of published work in the field of extraction dynamics is made. These studies of the transient behavior of liquid‐liquid extraction processes are summarized and evaluated. From these evaluations it is concluded that much work remains to be done for systems other than those involving simple extraction columns with terminal feeds and products, and also that pulse testing and frequency response analysis have become important tools for the determination of extraction dynamics. It was also concluded that staged models as opposed to differential contact models offer the most hope for realistic control and simulation studies.

The dynamics of extraction processes: Part IV. Frequency and time domain modeling of a mechanically agitated extractor

“…For the raffinate, the response curves of the peak show closer agreement but the initial delay in the calculated re- sults is reduced. For runs such as (1,2) where the feed to solvent ratio is low, this initial delay time is a significant quantity. Therefore, it is concluded that the mixing process detracts from the raffinate simulation by shifting the peak but the time delay adds to the agreement.…”

“…................. . (1) where Kea is an overall transfer coefficient which is independent of time and concentration ( 5 ) the equilibrium relation is linear and can be expressed as…”

“…................. . (1) where Kea is an overall transfer coefficient which is independent of time and concentration…”

Stochastic Analysis of a Counter-Current, Two-Phase Absorption or Extraction Column

“…It is possible with the aid of interphase transfer coefficients obtained under different operating conditions to use either model for design with equal success. Pollock and Johnson (1969) in their critical review of the dynamics of extraction problems concluded that the problems in obtaining the axial diffusivities, choosing the proper boundary conditions, and numerically solving the partial differential equations make the dispersion models unattractive for practical use. However, in the last 5 years at least the numerical problems have been resolved and to some extent the other two difficulties so that we prefer to use the dispersion model here because in principle it should be a more adequate model.…”

Mathematical modeling of a modified scheibel liquid‐liquid extraction column in the frequency domain

“…The frequency response of a system can be determined by using Equation (1) ..... and T,,(t) are output and input pulses which start initially with zero value and return to zero within finite periods of time Tpl and Tpp respectively.…”