Controlled-Cycle Operations Applied to Extraction Processes

Belter, P. A.; Speaker, S. M.

doi:10.1021/i260021a007

Cited by 24 publications

(5 citation statements)

References 6 publications

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“…This same problem does not exist for extraction and an extractor 6 inches in diameter with 40 trays has been built and operated (1). Extraction is an operation where there are other advantages to unsteady-state operation besides the capacity and efficiency increases.…”

Section: Applications To Various Operations-effectsmentioning

confidence: 99%

“…case for conventional distillation, the various assumptions may be removed by appropriate changes. For the 2th plate of the column (reboiler = stage 1) during the vapor-flow portion of the operation we have: dx H^=Vyt-1-Vyi (1) where V is the constant molar boilup rate, H is the liquidphase molar holdup on the plate (assumed to be the same and constant for all plates in the column), x{ is the liquid-phase mole fraction of the more volatile component on the zth plate, and y{ is the mole fraction of the more volatile component in the. vapor leaving the zth plate.…”

Section: Application Of Unsteady State-practical Aspectsmentioning

confidence: 99%

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Unsteady-State Processing

Schrodt¹

1967

Ind. Eng. Chem.

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Benefits can be obtained by deliberately operating a process in the unsteady state. Increases in efficiency and capacity of columns and flattening of velocity profiles in packed beds are some of the advantages over conventional steady-state processing. Examples are given from work in distillation, extraction, crystallization, ion exchange, and reaction engineering Unsteady-state processing promises to be an interesting area 58 INDUSTRIAL AND ENGINEERING CHEMISTRY

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Section: Applications To Various Operations-effectsmentioning

confidence: 99%

Section: Application Of Unsteady State-practical Aspectsmentioning

confidence: 99%

Unsteady-State Processing

Schrodt¹

1967

Ind. Eng. Chem.

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“…A range of modifications incorporating centrifugation, such as centrifugal partition chromatography (CPC) and high speed countercurrent chromatography (HSCCC) can speed up separation [3,[7][8][9][10][11][12][13][14][15][16][17], but the use of centrifugation increases the cost of equipment, especially on an industrial scale. In controlled-cycle pulsed liquid-liquid chromatography (CPLC), mixing of upper and lower phases is conducted in columns segmented into a cascade of chambers by horizontal perforated plates, yet equilibration of solutes between the phases still has to be achieved on a discontinuous basis with intervening pauses for phase separation in each transfer cycle [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Dispersed Mobile-Phase Countercurrent Chromatography

Xue

2016

Separations

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Countercurrent distribution based on liquid-liquid partition is a powerful separation method with minimal incurrence of loss of solutes, but its industrial application has been limited by cumbersome shifting of immiscible solvents. Although centrifugation has been employed to facilitate equilibration between phases, process scaling-up remains difficult. In this study, a dispersed mobile-phase countercurrent chromatography (DMCC) method has been developed to adapt the countercurrent distribution principle to a continuous column chromatography format. Continuous solute exchange between two immiscible phases within a series of separation columns is achieved by mechanical dispersion of an influx of mobile phase into an upward stream of small droplets travelling through the columns filled with stationary phase. The diameter, length, and number of columns, and the number of stationary phases employed in the different columns can be varied to match the requisite scale and resolution of operation. Illustrations of DMCC were provided by examples of solute separations where the fractionated solutes could be collected either from the eluate of the series of columns, or from drainage of the stationary phases in the individual columns at the end of a chromatographic run.

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“…Several publications considered the use of cyclic modes mainly for extraction and rectification [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…A theoretical analysis of cyclic extrac tion in a perforated column in the stationary and cyclic modes showed that the latter was preferable because of an increase in the driving force of mass transfer [5]. It was proven that in a counterflow apparatus in a cyclic mode with a finite number of actual stages N we can obtain a degree of separation corresponding to the number of theoretical stages 2N.…”

Section: Introductionmentioning

confidence: 99%