Packed Extraction Column Research Articles

Experimental modeling of slip velocity in an L-shape pulsed packed extraction column using response surface methodology

The “L-shaped pulsed packed extraction column,” a distinctive form of extraction column, is used in this study to examine the impacts of operational parameters and the physical features of the liquid systems on the slip velocity in a pilot plant. This assessment is done using response surface methodology (RSM). The operational factors of pulsation intensity, dispersed phase flow rate, and continuous phase flow rate are examined through the use of central composite design (CCD) on slip velocity. In the absence and presence of a mass transfer agent (acetone), two common liquid-liquid systems—butyl acetate and water and toluene and water—were used as the chemical systems. Interfacial tension, dispersion phase flow rate, and pulsation intensity are among the parameters that have been found to have a substantial impact on slip velocity. However, the slip velocity was either unaffected or was very slightly affected by the continuous phase flow rate and the mass transfer agent's presence. In addition, new practical models with R2 > 0.93 are presented to predict slip velocity by RSM. Finally, new comprehensive correlation based on dimensional analysis procedure, is put out to precisely forecast the slip velocity. For all of the investigated operating parameters and chemical systems, there was good agreement between predictions and experiments.

Flooding behavior of the standard liquid–liquid extraction systems in a pilot plant L-type pulse packed extraction column: Experimental study

In this study, the two-phase pressure drop and flooding velocity were investigated in a pilot plant of a new type of extraction column entitled “L-shaped pulsed packed extraction column” using two liquid-liquid systems of butyl acetate-water and toluene-water in the presence of acetone as the mass transfer agent. The effects of operating variables, physical properties, and the presence of mass transfer on the flooding flowrate and pressure drop were considered. It is found that the pressure drop is strongly influenced not only by the flow rates of the continuous and dispersed phases, but also by the pulsation intensity. That is, increasing the values of these parameters increases the shear stresses and the flooding phenomenon to occur sooner. Surprisingly, it is observed that increasing the pulsation intensity and dispersed phase flow rate reduces the maximum throughput of the column but increasing the continuous phase flow rate enhances that. Furthermore, it is achieved that the interfacial tension is a physical property which has significant impact on the flooding and the presence of mass transfer only affect at the low pulsation intensity. Finally, a new correlation is proposed to accurately predict the flooding velocity. Good adaptation between predictions and experiments was found for all investigated operational conditions, chemical systems, and with and without mass transfer.

Experimental investigation on drop size distribution and mean drop size in an L-shape pulsed packed extraction column

In this study, the mean drop diameter and drop size distribution have been investigated in a pilot plant of a new type of extraction column entitled “L-shaped pulsed packed extraction column” by using two liquid systems of toluene/acetone/water and n-butyl/acetone/water in the presence of mass transfer in two directions. The effects of operational variables, physical properties and mass transfer direction have been considered on the dispersed drop size. It is found that the mean drop diameter and drop size distribution is significantly affected by the pulsation intensity and interfacial tension of liquid system. However, the phases flow rates and mass transfer direction have a weaker impact. Furthermore, it is observed that the mean drops diameter in the horizontal and vertical sections of the used column have mostly the same size and it is considered as a significant advantage. Finally, new correlations are proposed to accurately predict the mean drop size and drop size distribution. Good agreement between predictions and experiments was found for all operating conditions, chemical systems and mass transfer direction that were investigated.

Flooding Behavior of the Standard Liquid–Liquid Extraction Systems in a Pilot Plant L-Type Pulse Packed Extraction Column: Experiment and Modeling

Flooding Behavior of the Standard Liquid–Liquid Extraction Systems in a Pilot Plant L-Type Pulse Packed Extraction Column: Experiment and Modeling

Experimental investigation on dispersed phase holdup in an L-shape pulsed packed extraction column

In this study, the dispersed phase hold-up has been investigated in a pilot plant of a new type of extraction column entitled “L-shaped pulsed packed extraction column” by using two liquid systems of toluene/acetone/water and n-butyl/acetone/water in the presence of mass transfer in two directions. The effects of operational variables, physical properties and mass transfer direction have been considered on the dispersed phase hold-up. It is found that the dispersed phase hold-up is significantly affected by the pulsation intensity, dispersed phase flow rate and interfacial tension of liquid system. However, the continuous phase flow rate and mass transfer direction have a weaker impact. Furthermore, it is observed that the behavior of hold-up in the horizontal and vertical sections of the used column is distinctive in some case. Such that any factor which reduces the dispersed drop size, leads to an increase in hold-up in the vertical section of the column and a decrease in hold-up in the horizontal section of the column. Finally, new correlation is proposed to accurately predict the dispersed phase hold-up. Good agreement between predictions and experiments was found for all operating conditions, chemical systems and mass transfer direction that were investigated.

Prediction of Flooding in Packed Liquid‐Liquid and High‐Pressure Extraction Columns Using a Gaussian Process

AbstractReliable prediction of flooding conditions is needed for sizing and operating packed extraction columns. Due to the complex interplay of physicochemical properties, operational parameters and the packing‐specific properties, it is challenging to develop accurate semi‐empirical or rigorous models with a high validity range. State of the art models may therefore fail to predict flooding accurately. To overcome this problem, a data‐driven model based on Gaussian processes is developed to predict flooding for packed liquid‐liquid and high‐pressure extraction columns. The optimized Gaussian process for the liquid‐liquid extraction column results in an average absolute relative error (AARE) of 15.23 %, whereas the algorithm for the high‐pressure extraction column results in an AARE of 13.68 %. Both algorithms can predict flooding curves for different packing geometries and chemical systems precisely.

Holdup and characteristic velocity in a pulsed packed extraction column

The present work aims to evaluate the hydrodynamics of a pulsed packed extractor, with an internal diameter of 0.026m and a length of 1.0m, using the liquid butanol-water system. Thus, the basic parameters obtained for the hydrodynamic study of the extraction column in question as dispersed phase, slip velocity, characteristic velocity and flooding point. The methodology used in the work consisted of determining the holdup fraction of the dispersed phase, obtained through tests of simultaneous interruptions in the column feedings. The effects of frequency pulsation, dispersed phase flow rate and continuous phase flow rate investigated in the analysis of these parameters. New empirical correlations derived from the predictions of the parameters studied obtained in terms of operating variables and physical properties of the liquid system involved. The average absolute value of the relative error (AARE) was always below 5.6%. Good agreement between calculated and experimental results observed for all investigated operating conditions.

Hidrodinamičke karakteristike pulzacionih ekstrakcionih kolona sa punjenjem

This work presents an overview of the research related to the determination of hydrodynamic characteristics of pulsed packed extraction columns using different liquid-liquid two-phase systems. The following hydrodynamic characteristics are examined: flooding velocity, mean drop diameter of the dispersed phase, the dispersed-phase holdup, and an axial dispersion coefficient. In this paper, the effects of operating parameters (pulsation velocity, superficial velocities of the phases) on the flooding point data taken from the literature are analyzed. The experimental data taken from the literature indicate that the maximum throughput of extraction devices decreases with an increase in pulsation velocity and the flow rate of the phases. By comparing these experimental data for liquid-liquid two-phase systems presented in the literature, it has been concluded that the overall flooding velocity decreases with increasing the flow rate ratio of the phases. It has been determined that the Sauter mean drop diameter is significantly dependent on pulsation velocity and interfacial tension, and that it is not a function of flow rates of the phases. The dispersed-phase holdup has been shown to increase with increasing the flow rate ratio, reaching its maximum value at the flooding point, when small drops are formed. It has been concluded that the dispersed-phase holdup increases with an increase in the flow rate ratio. The authors have presented and analyzed some of the empirical correlations taken from the literature for flooding velocity, mean drop diameter, dispersed-phase holdup, and axial dispersion coefficient as functions of operating parameters, packing characteristics, and physical properties of liquid-liquid systems.

Use of axial dispersion and plug flow models for determination of axial mixing and mass transfer coefficient in an l‐shaped pulsed packed extraction column

In this study, the volumetric overall mass transfer and phases axial mixing coefficients have been investigated in a pilot plant of an L‐shaped pulsed packed extraction column by using two liquid systems of toluene/acetone/water and n‐butyl/acetone/water. The mass transfer performance has been evaluated using two methods of axial dispersion and a plug flow model. The effect of the operational variables and physical properties, including the dispersed and continuous phases flow rates, pulsation intensity, and interfacial tension, on mass transfer and phases axial mixing coefficients have been considered. It has been found that the pulsation intensity and the continuous phase flow rate seriously affect the mass transfer coefficient, however, the dispersed phase flow rate has a weaker effect. Also, the axial mixing of a phase is strongly affected by the pulsation intensity and the flow rate of the phase itself and it is not affected by the second phase flow rate. Finally, new correlations are proposed to accurately predict the mass transfer and axial mixing coefficients.

Applying forward mixing model in an L-shape pulsed packed extraction column to investigate the influence of drop size distribution on mass transfer

The objective of this work is to model the effect of drop forward-mixing on the mass transfer efficiency of a two phase countercurrent extraction process. Based on the flow mechanism and drop size distribution in extraction columns, a novel model with a simplified sequential algorithm is developed. Unlike the other models that use mean diameter of the dispersed phase droplets, this model accurately considered the effect of drop size distribution on mass transfer efficiency. On the base of this model the volumetric overall mass transfer coefficient has been investigated in a pilot plant of L-shape pulsed packed extraction column by using two liquid systems of toluene/acetone/water and butyl acetate/acetone/water. It is found that, although the mass transfer coefficient related to the large droplets is larger but the corresponding volumetric overall mass transfer coefficient is less than that related to the small droplets. Therefore, any factor that reduces the drop size can improve the efficiency of mass transfer. Furthermore, the effect of operational variables and physical properties including the dispersed and continuous phases flow rates, pulsation intensity and interfacial tension have been considered on mass transfer coefficients. It has been found out that the pulsation intensity and the continuous phase flow rate have seriously affected on mass transfer coefficient, however, the dispersed phase flow rate has a weaker effect. Finally, new correlations are proposed to accurately predict the mass transfer coefficient, axial mixing and drop size distribution. Good agreement between predictions and experiments was found for all operating conditions that were investigated.

Systematic and Model-Assisted Process Design for the Extraction and Purification of Artemisinin from Artemisia annua L.—Part II: Model-Based Design of Agitated and Packed Columns for Multistage Extraction and Scrubbing

Liquid-liquid extraction (LLE) is an established unit operation in the manufacturing process of many products. However, development and integration of multistage LLE for new products and separation routes is often hindered and is probably more cost intensive due to a lack of robust development strategies and reliable process models. Even today, extraction columns are designed based on pilot plant experiments. For dimensioning, knowledge of phase equilibrium, hydrodynamics and mass transport kinetics are necessary. Usually, those must be determined experimentally for scale-up, at least in scales of DN50-150 (nominal diameter). This experiment-based methodology is time consuming and it requires large amounts of feedstock, especially in the early phase of the project. In this study the development for the integration of LLE in a new manufacturing process for artemisinin as an anti-malaria drug is presented. For this, a combination of miniaturized laboratory and mini-plant experiments supported by mathematical modelling is used. System data on extraction and washing distributions were determined by means of shaking tests and implemented as a multi-stage extraction in a process model. After the determination of model parameters for mass transfer and plant hydrodynamics in a droplet measurement apparatus, a distributed plug-flow model is used for scale-up studies. Operating points are validated in a mini-plant system. The mini-plant runs are executed in a Kühni-column (DN26) for extraction and a packed extraction column (DN26) for the separation of side components with a throughput of up to 3.6 L/h, yield of up to 100%, and purity of 41% in the feed mixture to 91% after washing.

Mass transfer of molybdenum in L35 + sodium sulfate + H2O aqueous two-phase system with a packed column

Abstract The mass transfer characteristics of molybdenum in a packed extraction column using a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer surfactant (L35) + sodium sulfate + H2O aqueous two-phase system was studied. The hold up of dispersed phase (eD) and the overall volumetric mass transfer coefficient of the dispersed phase (KDa) were measured with three kinds of packings, such as ceramic rasching rings, metal θ rings and glass springs under different conditions. The experimental results showed that the hold up of dispersed phase increases with increasing the flow rate of the dispersed phase, and decreases with the increase of the tie line length (TLL), and increases as increasing the void fraction of the packings. The mean residence time and the Peclet number of the dispersed phase decrease, showing that the axial diffusion extent of the dispersed phase become more serious with increasing the rate of dispersed phase and TLL, and increase with the increase of the void fraction of packing bed according to the sequence of ceramic raschig rings – glass springs – metal θ rings. The overall volumetric mass transfer coefficient of dispersed phase increases with the increase of the rate of dispersed phase and continuous phase and the specific area of three kinds of packings, and decreases with increasing TLL and operating temperature. The mass transfer resistance of two phases is not disregarded.

Influence of quadrupole magnetic field on mass transfer in an extraction column in the presence of MnFe2O4 nanoparticles

Recently, it has been observed that the use of magnetic nanoparticles and the magnetic field would result in heat and mass transfer intensification. But most of the investigations have been devoted to the enhancement of heat transfer. However, the investigations on the applicability of magnetic nanoparticles for mass transfer improvement are still in the developing stage. In the present study, the effect of MnFe2O4 nanoparticles on the mass transfer performance of a packed extraction column is evaluated in the presence of constant and alternating magnetic fields. The column is filled with Penta-Pak TM PS-500M1 structured packing; while four identical bar electromagnets made from zinc ferrite cores are used to generate the quadrupole magnetic field. The (toluene-acetic acid)-water system is employed. Spinel-type manganese ferrite nanoparticles are added to the organic dispersed phase (toluene+acetic acid) to intensify solute transfer. The quadrupole magnetic field is applied from 100 to 500G intensity and 100 to 500Hz frequency, accompanied with different nanoparticle concentrations from 0.001wt% to 0.005wt%. According to our observations, mass transfer performance increases remarkably in the presence of magnetic nanoparticles under the influence of magnetic field. Compared with no magnetic field, maximum improvements of 115% and 43% in overall mass transfer coefficient and extraction fraction are observed under alternating magnetic field with 300Hz frequency and 500G intensity for 0.003wt% nanoparticle concentration. That is, by using the magnetic nanoparticles and the magnetic field, one can considerably improve the performance of a liquid-liquid extraction system.

Mass transfer investigation in a horizontal–vertical pulsed packed extraction column

In this study, hydrodynamic parameters and the mass transfer coefficient were investigated in a pilot plant of a horizontal–vertical pulsed packed extraction column using a toluene–acetone–water system.

Axial dispersion model in predictive mass transfer correlation for random pulsed packed column

The continuous phase volumetric overall mass transfer coefficient in a ceramic intalox saddle pulsed packed extraction column using axial dispersion model was studied for two different liquid-liquid systems containing water/acetone/toluene and water/acetone/n-butyl acetate. The effects of pulsation intensity, continuous and dispersed phase flow rates on mass transfer coefficient were investigated. The experimental results indicated that the mass transfer coefficient was enhanced by increasing pulsation intensity and dispersed and continuous phase flow rates. The utilization of nonlinear least square method provided a new predictive correlation for the continuous phase overall mass transfer coefficient. The developed mass transfer model was validated via the comparison of the modeling data with experimental results with 18.7% average absolute relative error (AARE). Furthermore, one empirical correlation was developed for prediction of the continuous phase overall mass transfer coefficient as the function of the aforementioned operating variables.

Spray and packed liquid–liquid extraction columns: drop size and dispersed phase mass transfer

ABSTRACTThe effects of holdup on Sauter mean drop diameter, D32, and dispersed phase mass transfer coefficient have been studied in the spray and packed extraction columns. For both columns, two well‐defined regions for the dependence of D32 on holdup were observed. D32 increased and decreased with an increase in holdup at low and high levels of holdup, respectively. Changes in dispersed phase mass transfer coefficient against holdup were shown to be similar to D32 for both columns. Moreover, empirical correlations have been derived to predict D32 and dispersed phase mass transfer coefficient for both columns. It has been shown that the derived correlations are in a good agreement with the experimental data. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Drop size distribution and mean drop size in a pulsed packed extraction column

Drop size distribution and mean drop size are used for calculation of interfacial area available for mass transfer. In this study, the drop size distribution and Sauter mean drop diameter (d32) have been investigated using three different liquid systems in the absence of mass transfer in a pilot plant pulsed packed column. The drop size was measured at four different points along the active column height. Three operating variables have been studied including the pulse intensity (af) and flow rates of both liquid phases. The effect of liquid properties and height of the active column were also investigated. A combination of the pulse intensity and interfacial tension had the largest effect on the drop size distribution while none of the flow rates were of significance. The height of the column played an important role at the bottom of the active column, but the associated effect was reduced with increase of the height. Finally, a normal probability function of number density was proposed for prediction of the drop size distribution with an Average Absolute Relative Error (AARE) of 8.8% for their optimized constant. Furthermore, two correlations were presented involving height or flow rates of the two phases along with operating variables and physical properties of the liquids. These correlations had AARE values of about 8.5 and 7.8%, respectively.

A facile detection of acrylamide in starchy food by using a solid extraction-GC strategy

The acrylamide content in microwaved food has been highly concerned because of food safety; meanwhile, the detection of acrylamide content in starchy food is difficult due to the stickiness. In this experiment, a facile MS-free method was demonstrated to determine acrylamide content in microwaved and conventional heated popcorn and rice, using activated carbon packed extraction column coupling with simple GC analysis. The detection limit of acrylamide is 10 ng/mL. The recovery ratio of acrylamide in sample was 100.60% with a RSD of 1.2%–4.6%. The detection RSD of the acrylamide contents in microwaved caramel sweet popcorn and cooked rice were 1.46% (n = 10) and 1.20% (n = 3), respectively.

Dispersed phase hold-up and characteristic velocity in a pulsed packed extraction column

Dispersed phase hold-up has been measured in a 76.2 mm diameter pulsed packed column for four different liquid-liquid systems. The effects of pulsation intensity, phase ratio, and packing characteristic on the hold-up have been investigated under a variety of operating conditions. The dispersed phase axial hold-up shows a strong non-uniformity, depending on the operating conditions. The results indicated that the characteristic velocity approach is applicable to this type of extraction column for analysis of hold-up. An empirical correlation is derived for prediction of the hold-up in terms of operating variables, physical properties of the systems, and packing geometry. Good agreement between prediction and experiments was observed for all investigated operating conditions.

Flooding characteristics in pulsed packed extraction columns

Flooding behavior of a 76.2 mm diameter pulsed packed column has been determined using four different liquid-liquid systems. The effects of pulsation intensity, flow ratio, interfacial tension, and packing geometry on flood point have been investigated. The results showed that the maximum throughput of the column decreases with an increase in pulsation intensity and flow ratio, while it increases with an increase in interfacial tension. The applicability of the characteristic velocity method to this type of column for the analysis of the flood point was examined and a marked deviation was observed between experimental results and values calculated by this method. Two new empirical correlations for flooding velocity and holdup at flooding are derived in terms of operating variables, packing characteristics, and physical properties of the liquid systems. Good agreement between prediction and experiments has been found for all operating conditions that were investigated.