Study on Dispersed-Phase Axial Dispersion in an Agitated–Pulsed Solvent Extraction Column with a Step Tracer Injection Technique

Tan, Boren; Zhang, Yanlin; Wang, Yong; Qi, Tao

doi:10.1021/acs.iecr.1c00506

Cited by 7 publications

(5 citation statements)

References 42 publications

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“…The axial dispersion coefficients for both phases were calculated using Tan's method. 15 4 | RESULTS AND DISCUSSION…”

Section: Computational Proceduresmentioning

confidence: 99%

“…

u_{bold0 bold-italic- bold1}

is set as 0 by assuming that there is no droplet above the dispersed phase inlet. The axial dispersion coefficients for both phases were calculated using Tan's method 15 …”

Section: Mathematical Modelmentioning

confidence: 99%

“…It is expected to be capable of achieving the formation of smaller droplets with a narrow size distribution compared to other conventional pilot plant columns. Our previous studies on the hydraulics 13,14 and axial dispersion characteristics 15 have shown that APC provides much higher interfacial area while with similar axial dispersion coefficients compared with the conventional extraction columns. Furthermore, a DN32 APC has shown high hydrodynamic throughput and nearly twice as high mass transfer efficiency as that of Kühni's column of the same scale 16,17 .…”

Section: Introductionmentioning

confidence: 98%

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Modeling the axial distribution of mass transfer coefficient in an agitated‐pulsed extraction column

Tan

Wang

et al. 2022

AIChE Journal

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The dispersed phase holdup and drop size in solvent extraction columns vary along the column height and this affects the mass transfer coefficient and interfacial area. In this article, mass transfer study was performed experimentally using a 25 mm diameter agitated pulsed column. The axial distribution of mass transfer coefficient was determined by coupling population balance equation and axial dispersion model by taking the longitudinal variation in hydrodynamic performance into consideration. Feasibility of different mass transfer models in predicting concentration profiles was evaluated and a novel correlation based on effective diffusivity was developed. The results showed that both overall and volumetric mass transfer coefficients have significant change along the column height and greatly depends on the agitation speed and pulsation intensity. Increasing dispersed phase velocity also augments the overall mass transfer coefficient. The maximum number of transfer unit was measured to be 10 m−1 at agitation speed of 1000 rpm.

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“…The axial dispersion coefficients for both phases were calculated using Tan's method. 15 4 | RESULTS AND DISCUSSION…”

Section: Computational Proceduresmentioning

confidence: 99%

“…

u_{bold0 bold-italic- bold1}

is set as 0 by assuming that there is no droplet above the dispersed phase inlet. The axial dispersion coefficients for both phases were calculated using Tan's method 15 …”

Section: Mathematical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Modeling the axial distribution of mass transfer coefficient in an agitated‐pulsed extraction column

Tan

Wang

et al. 2022

AIChE Journal

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“…However, it should be noted that all of the drag coefficient models mentioned above were developed for steady motion, which has significant differences from the flow field in industrial equipment. Especially, in extraction columns such as pulsed disks and doughnut columns (PDDCs), , pulsed sieve-plate columns (PSPCs), , Karr reciprocating plate columns, , and agitated-pulsed columns (APCs), , the droplets experience reciprocal acceleration and deceleration due to the input of reciprocating energy. , It has been reported that the unsteady effect accounts for ∼50% of the standard drag coefficient in the range of low Reynolds number …”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Unsteady Drag Coefficient of Droplets in a Liquid–Liquid System

Tan

Wang

Zhang

et al. 2023

Ind. Eng. Chem. Res.

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In liquid−liquid contact process, the motion of droplets relative to the surrounding fluid always involves accelerating and decelerating, which affects the mass, heat, and momentum transfer. The lack of experimental data of the unsteady drag coefficient has been one of the limitations on the prediction of the unsteady flow field. In this study, the accelerated and decelerated water droplets in an organic phase were measured by a high-speed camera. The results show that with a decrease in droplet diameter, the acceleration becomes more significant, while the absolute relative velocity decreases, causing a lower Reynolds number. The Basset force and add mass force were solved numerically and compared with drag force. The unsteady drag coefficient is always smaller than the corresponding steady drag coefficient in the case of accelerating relative flow and larger than that in the case of decelerating relative flow. A new unsteady drag coefficient model has been established, which has an acceptable agreement with the experimental data.

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“…The mass transfer is related to the hydrodynamic characteristics of the pulsed extraction column, such as axial dispersion, [1][2][3][4] holdup, [5][6][7] and slip velocity, 8,9 and the characteristics of mass transfer can affect the extraction behaviors in the column. In liquid-liquid two-phase countercurrent, the main factors affecting and determining the mass transfer process are specific surface area, contact time, and so on.…”

Section: Introductionmentioning

confidence: 99%

Study on a new four‐fiber sensor signal processing algorithm of hydrodynamic characteristics in liquid–liquid two‐phase flow

Yan

Xie

Chen

et al. 2022

Asia-Pacific J Chem Eng

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In the process of two‐phase countercurrent flow in the extraction column, the study of the hydrodynamic characteristics of dispersed phase droplets is crucial for the design and scaling up of the extraction column. In a pulsed extraction column with a liquid–liquid system, the four‐sensor optical fiber probe was used to assess the hydrodynamic characteristics of the dispersed phase droplets, including size, mean velocity, and holdup. 1 M HNO3 and 30% TBP/kerosene were used as continuous phase and dispersed phase, respectively. The effects of two‐phase superficial velocities and pulsation intensity were investigated on droplet size, mean velocity, and holdup. The findings show that aside from the local holdup, the pulsation intensity has the greatest impact on the hydrodynamic characteristics. A new and concise algorithm was used to deal with the light signals to determine the droplet size and mean velocity. This algorithm created two Cartesian coordinate systems, each with a separate z‐axis using the leading probe as the origin of the coordinate instead of using the vector approach. Compared to the previous algorithm, both the needed number of the time interval between the voltage peaks and that of the direction angles decrease. The relative error of the droplet size obtained by this improved algorithm is within 7%, and droplet velocity is almost the same, compared to the previous algorithm, which indicates that the new algorithm of the four‐sensor optical fiber signal processing is reliable to the measurement of the hydrodynamic characteristics.

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Study on Dispersed-Phase Axial Dispersion in an Agitated–Pulsed Solvent Extraction Column with a Step Tracer Injection Technique

Cited by 7 publications

References 42 publications

Modeling the axial distribution of mass transfer coefficient in an agitated‐pulsed extraction column

Modeling the axial distribution of mass transfer coefficient in an agitated‐pulsed extraction column

Experimental Study of Unsteady Drag Coefficient of Droplets in a Liquid–Liquid System

Study on a new four‐fiber sensor signal processing algorithm of hydrodynamic characteristics in liquid–liquid two‐phase flow

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