Untersuchungen zum hydrodynamischen Betriebsverhalten einer Kühni‐Extraktionskolonne

Bailes, Phillip Jensen; Gledhill, Jeffrey; Godfrey, J.C.; Slater, M.J.

doi:10.1002/cite.330581010

Cited by 11 publications

(9 citation statements)

References 10 publications

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“…A solvent inlet distributor placed at the bottom of the column contained 18 holes 3.18 mm in diameter (see Fig. l b in Bailes et al [26]). This column was used with solvent flow in the absence of continuous-phase water flow to obtain drop size measurements for a swarm of drops.…”

Section: Experimental Equipment and Systemsmentioning

confidence: 99%

Studies of drop break‐up in liquid‐liquid systems in a rotating disc contactor. Part I: Conditions of no mass transfer

Bahmanyar

Slater

1991

Chem Eng & Technol

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Observations on the break-up of single drops in a rotating disc contactor show that there is a critical rotor speed below which drops of a given size do not break. Weber and Reynolds numbers are required to correlate the data and not simply a Weber number as for turbine agitated systems. The probability of break-up of a drop at the rotor edge is expressed in terms of a Weber number with a lower limit for critical conditions. The mean number of daughter drops produced on break-up is correlated as a simple function of drop diameter based on the critical diameter and agreement is found with data from other types of agitated equipment.

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Section: Experimental Equipment and Systemsmentioning

confidence: 99%

Studies of drop break‐up in liquid‐liquid systems in a rotating disc contactor. Part I: Conditions of no mass transfer

Bahmanyar

Slater

1991

Chem Eng & Technol

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“…The elements of vector P consist of the physical system properties ([l q r]), and K t is a slowing factor taking into account the effect of the column internal geometry on the droplet terminal velocity (0 < K < 1) [17,18]. A useful guide for selecting the suitable droplet terminal velocity based on the shape of the droplet (rigid, oscillating or circulating) and hence on the physical system properties could be found elsewhere [19].…”

Section: Population Balancesmentioning

confidence: 99%

“…Basic scale-up and design rules for Kühni columns [7,8] permit a good estimate of the column performance, but are limited to pilot scale (DN150) design. In that respect, several authors [5,[8][9][10][11] contributed correlations from experimental data with test systems to characterize the pilot-scale column performance. The information to scale from pilot to industrial size is then on some basic rules [12] and believed to be manufacturers' know-how.…”

Section: Introductionmentioning

confidence: 99%

Scale‐up of Mini‐Plant Extractors on Energy Dissipation‐Based Population Balances

Steinmetz

Bart

2009

Chem Eng & Technol

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The new scale-up concept for extraction columns relies on three identities being kept idem, as is the total specific flow rate, energy dissipation, and mean droplet residence time in a compartment. The droplet population balance-based model allows maintaining hydrodynamic similarity in different geometries, as is in a mini-or a pilot plant. This leads to similar breakage and coalescence probabilities giving comparable droplet size distributions, thus mass transfer area and extraction efficiency. A new breakage frequency term has been developed relying on the energy dissipation rate and is thus independent from geometric constraints. The traditional scale-up rules are based either on a constant tip velocity (≈ N) or on a constant energy input (≈ N 3 ), whereas here it follows a constant energy dissipation (≈ N 2 ). A step-by-step approach to the new procedure proved by case samples is given. Data from literature pilot experiments could be verified by computer simulations, without using adaptable parameters. All parameters in the correlations where derived in a lab-scale apparatus and the coalescence parameters were obtained in the mini-plant experiments. Derivation between simulated and experimental pilot data for stage numbers was less than 14 %, operating parameters (rotational speed N, throughput) were underestimated by 4 % leading to a slightly smaller HETS (Height Equivalent of Transfer Stages) value as measured, affecting the column height with less than 1 %.

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“…The interfacial area in the collector (funnel) was kept small by occasionally pulling the drops into a pipette. The error in measuring the concentration just above the needle may be problematical but there may no reasonable alternative procedure [24]. Except other wise mentioned all the experiments were conducted with the aqueous phase continuous and the organic phase dispersed at laboratory ambient temperature 25 ± 2°C.…”

Section: Apparatus and Proceduresmentioning

confidence: 99%

“…The nozzle tips were immersed approximately 5 mm in the continuous phase and the run was initiated by positioning the feed needle valve and starting the stopwatch. The best procedure is to capture drops at a point just above the needle tip where drops are formed [24]. To keep the mass transfer during drop rise from the needle top (2 mm) as small as possible a small collector was used.…”

Section: Apparatus and Proceduresmentioning

confidence: 99%

Modelling Mass Transfer Coefficients During Drop Formation

Hashem¹,

Aimaghrabi²

2013

JESTR

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A concise review of relevant experimental observations and modelling of mass transfer during drop formation, based on recent studies, is presented. Empirical and theoretical models developed for drop formation are briefly described. Experimental investigations are also performed to explore the mass transfer during drop formation in extraction column and to evaluate the effect of different parameters on the rate of formation. The effects of formation time, which is of industrial relevance, on the mass transfer from drops are discussed. It has been found that the mass transfer coefficients are largest in the initial stages of drop formation when convection is most significant. The resulting data was used to check the available models in the literature. A comparison between the experimental data and the available models in the literature has been made and a modified new correlation was suggested. The results would provide the basic information about the rate of drop formation and design of extraction column, and consequently the environmental impact of solvent extraction processes. Hence, the potential for increasing the reliability of these results is correspondingly increased.

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Untersuchungen zum hydrodynamischen Betriebsverhalten einer Kühni‐Extraktionskolonne

Cited by 11 publications

References 10 publications

Studies of drop break‐up in liquid‐liquid systems in a rotating disc contactor. Part I: Conditions of no mass transfer

Studies of drop break‐up in liquid‐liquid systems in a rotating disc contactor. Part I: Conditions of no mass transfer

Scale‐up of Mini‐Plant Extractors on Energy Dissipation‐Based Population Balances

Modelling Mass Transfer Coefficients During Drop Formation

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