Ind. Eng. Chem. Res. 2001, 40, 681-688
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Novel Type of Impinging Streams Contactor for Liquid-Liquid Extraction Asghar Molaei Dehkordi† Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran
An experimental study was conducted on liquid-liquid extraction of succinic acid by means of normal butanol from its aqueous solution (BSW), iodine from its aqueous solution by means of kerosene (KIW), and acetic acid by means of distilled water from kerosene (WAK) in a novel type of contactor based on an impinging streams technique. This high-intensity jet contactor provides significant improvement over the conventional extractor because of the impingement of high-velocity feed streams upon one another in a relatively small contactor volume, resulting in a high-turbulent mixing of two phases. As a result of both the impinging process and shear forces exerted on the phases, the overall volumetric (capacity) mass-transfer coefficients, KLa, of up to 15, 23, and 26 min-1 have been obtained for BSW, KIW, and WAK, respectively. The order of magnitudes of the latter coefficients are higher than typical values obtained by conventional extractors. In addition, the effects of the upper disk speed, solution flow rate, disk diameter, distance between disks and the enhancing effect of impinging streams have been investigated. These experimental results verify the capability of the new contactor in liquidliquid extraction. 1. Introduction Liquid-liquid extraction is widely used in chemical process industries. The industrial applications of liquidliquid extraction are extensive. Typical applications of liquid-liquid extraction are in petroleum, food, hydrometallurgy, and chemical industries. Impinging streams (IS), used as a method for enhancing heat- and mass-transfer processes, have been employed by Elperin1 and further developed by Tamir.2 The method has been successfully applied to the absorption and desorption of gases;3-9 dissolution of solids;10 drying of solids;11 dust collection;12 absorption with chemical reactions;13,14 two-liquid-phase chemical reaction;15 mixing;16 bioreaction;17 solid-liquid enzyme reaction;18 and evaporative cooling of air.19 The advantage of using the IS technique in chemical processes is that the contactor volume is greatly reduced and, hence, the investment costs and the space required for the system may also be reduced in comparison to conventional systems which usually have relatively low mass-transfer performance. However, in most cases, the high-performance systems require high-power input. The advantages of utilizing the IS technique in chemical processes, on the one hand, and the importance of liquid-liquid extraction processes, on the other hand, persuaded the present author to consider the application of such a technique in liquid-liquid extraction by employing a novel-type IS contactor. It should be noted that the application of two types of IS contactors in liquid-liquid extraction has been reported elsewhere.2,20 In the present study, an experimental investigation on the liquid-liquid extraction of succinic acid from its aqueous solution using normal butanol as the solvent (BSW); iodine from its aqueous solution by means of kerosene (KIW); and acetic acid from kerosene by means of distilled water (WAK), applying a novel-type IS † E-mail:
[email protected]. Fax: 98-21 2071251. Tel: 98-21 2078294.
Figure 1. Experimental setup: (1) circular disks; (2) variablespeed motor; (3 and 4) solution rotameters; (5 and 6) feed vessels; (7) feed pumps; (8) needle valves; (9) cylindrical vessel; (10) dispersion outlet; (11) sampling cup.
contactor, has been conducted. In addition, the performance capability of the new contactor in liquid-liquid extraction has been investigated. In the experiments, the effectiveness of the IS contactor was tested by employing a non-IS contactor. 2. Experimental Section 2.1. Chemicals. All chemicals used as solutes as well as normal butanol in this study were all of analytical grade. 2.2. Apparatus. The experimental apparatus, shown in Figure 1, consists of the following parts: (1) two circular disks made of stainless steel, type 304, of 0.20 m diameter and 0.0015 m distance between disks; (2) a variable-speed electric motor in order to study the effect of the upper disk speed on the extraction efficiency. It should be noted that in the present study only the upper disk was rotated and the lower disk was fixed. A schematic diagram of the disks is given in Figure 2. The aqueous and organic solutions were fed into the lower and upper disks, respectively. Thus, the contact between
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Figure 2. Cross section of the circular disks.
the phases took place within the extraction compartment only. Other parts of the experimental system were as follows: (3 and 4) solution rotameters; (5 and 6) feed and stock solution vessels both made of stainless steel type 304; (7) feed pumps made of stainless steel type 304; (8) needle valves made of stainless steel type 316 used for adjusting the solutions flow rates; (9) cylindrical vessel used for collection of the dispersion leaving the extraction compartment; (10) dispersion outlet; (11) sampling cup. In addition, the circular disks have been equipped with two simple nozzles of 0.001 m diameter in order to introduce high-velocity jets to one another. 2.3. Start-Up Procedure and Measurements. In each experimental run, the upper disk speed was adjusted at the desired value and aqueous and organic solutions were fed to the contactor. The solution flow rates were regulated using the needle valves. When steady-state conditions were established, samples were drawn to the sampling cups. It should be noted that taking the sample from the dispersion leaving the disks was rather difficult and took a longer time than taking the sample at the outlet of the cylindrical vessel. Therefore, it was decided that a number of preliminary experiments should be conducted before performing the final experimental runs in order to find the errors that might arise from taking the samples at the vessel outlet. To achieve this goal, the cylindrical vessel was provided with a hole positioned on the cylindrical vessel’s wall, which was used for taking the samples at the outlet of the disks and also for adjusting the distance between disks. The experiments have been carried out for liquid flow rates of 0.11 and 0.300 dm3 min-1 and upper disk speeds, N, of 600-1400 rpm. Because the time needed for complete separation of dispersion in the sampling cups is usually long compared to the contact time in the extraction compartment, the collected samples were put immediately into a centrifuge for a rapid separation of the liquid dispersion into two distinct layers. The experiments have been repeated by taking the samples at both the vessel outlet and the disk outlet. The experimental results related to the extraction of succinic acid are summarized in the following table (error was defined as the difference between the concentration of the solute in the aqueous phase at the exit of the disks and the cylindrical vessel outlet in units of kg m-3): upper disk speed, N (rpm)
error at QA ) 0.110 dm3 min-1
error at QA ) 0.300 dm3 min-1
600 1000 1400
0.065 0.035 0.0
0.10 0.045 0.0
According to these experimental results, the final results have been modified.
Quantitative analyses of the aqueous samples were performed by titration, using a standard sodium hydroxide solution as the titrant for both succinic acid and acetic acid samples and using sodium thiosulfate for iodine samples. The accuracy of the analytical methods was tested using known samples of aqueous solutions. The maximum error did not exceed (3%. It should be noted that each data point represents the mean value of at least three measurements of the outlet concentration of aqueous solutions with a standard deviation of 4-6%. To explore which phase was a continuous phase and which one was a disperse phase, a number of experiments were conducted on the measurement of the conductivity of the outlet dispersion by using Konductometer CG 857 from Schott Gerate with measuring cell constant k ) 1.01 cm-1 at the upper disk speed of 6001400 rpm. It was found that the aqueous solution was a continuous phase at the exit of the contactor. 3. Results and Discussion The effects of the upper disk speed, solution flow rates, disk diameters, and distance between disks and the effectiveness of IS were tested in the experiments. The operating conditions were as follows: (a) Upper disk speed, N: 600-1400 rpm (b) Temperature within the contactor: ∼18 °C (c) Aqueous to organic flow ratio (A/O): 1:1 (d) Flow rate of liquid solutions: 0.110-0.300 dm3 min-1 (e) Pressure of the liquid phases at the inlet of the rotameters: ∼0.65 atm (f) Concentration of succinic acid in an aqueous solution at the inlet of the contactor: 10 kg m-3 (g) Concentration of iodine in an aqueous solution at the inlet of the contactor: 0.94 kg m-3 (h) Concentration of acetic acid in kerosene at the inlet of the contactor: 2.0 kg m-3 (i) Specific gravity of kerosene at 15 °C: 0.81 (j) Kinematic viscosity of kerosene: 1.02 × 10 - 4 m2 min-1 (k) Concentration of normal butanol: 99.9% 3.1. Definition of the Extraction Efficiency, Extraction Rates, and Overall Volumetric MassTransfer Coefficients. The extraction efficiency may be expressed as follows:
E)
CA,i - CA,o / CA,i - CA,o
(1)
where CA,i and C A,o are concentrations of solutes in the inlet and outlet aqueous solutions, respectively, and / is the equilibrium concentration of solutes in the CA,o outlet aqueous phases. Because the surface area between the immiscible phases in the extraction was not known, the overall volumetric mass-transfer coefficients, KLa, were determined from the experimental results. The parameter KLa is normally defined by the equation
R ) QA(CA,i - CA,o) ) KLaVc∆Cm
(2)
where a, Vc, QA, R, and ∆Cm are the interfacial masstransfer area between the phases per unit volume of the contactor, contactor volume, volumetric flow rate of aqueous solutions, extraction rates, and an appropriate
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Figure 3. Effect of the upper disk speed on the extraction efficiency of succinic acid: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 4. Effect of the upper disk speed on the extraction efficiency of iodine: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
mean concentration driving force, respectively. Because the state of mixing of the phases in the contactor was not known, the logarithmic mean concentration driving force, ∆Cln, was used to calculate KLa. It should also be noted that using this mean concentration driving force will lead to lower KLa values. The logarithmic mean concentration driving force, ∆Cln, is generally given by
∆Cln )
/ / (CA,i - CA,i ) - (CA,o - CA,o ) / / ln[(CA,i - CA,i )/(CA,o - CA,o )]
(3)
/ where CA,i is the equilibrium concentration of the solutes in the inlet aqueous phase, corresponding to the actual inlet concentration of the solutes in the other / is the equilibrium concentration of the phase, and CA,o solutes in the outlet aqueous phase, corresponding to the actual outlet concentration of the solutes in the other phase. Notice that eqs 1 and 2 should be rearranged in the following forms for extraction of acetic acid from kerosene by means of distilled water:
E)
CA,o - CA,i / CA,o - CA,i
R ) QA(CA,o - CA,i) ) KLaVc∆Cm
Figure 5. Effect of the upper disk speed on the extraction efficiency of acetic acid: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
(4) (5)
3.2. Evaluation of the Settling Characteristic of the Phases. There is always the question of how easy it would be to separate the phases after contact within the extraction compartment. Often in extractors, the phase separator is a larger piece of equipment than the contactor. Therefore, this important question should be answered before any attempt to design a certain new kind of extractor. Otherwise, the latter would be questionable. To test the settling characteristic of the phases leaving from the contactor and to compare the latter with a conventional mixer, an attempt was made to compare the dispersion band thickness of the two systems in a gravity settler. To achieve this goal, a number of preliminary experiments had to be conducted before performing the final experimental runs. The conventional mixer used in this study was a laboratoryscale tank with an active volume of 2.0 dm3 equipped with a turbine-type impeller. The settler was a horizontal Pyrex cylindrical vessel of 0.20 m length and 0.064 m diameter. This settler was used in both systems. The interface was controlled near the midpoint of the settler by a simple gravity leg positioned on the
Figure 6. Effect of the upper disk speed on the overall volumetric mass-transfer coefficient of BSW: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
aqueous discharge. The experiments were carried out in the continuous mode of operation with identical flow rates for both systems. It was found that there were no significant differences in the dispersion band thicknesses of the contactor and conventional mixer, especially at the upper disk speeds below 1400 rpm. 3.3. Effect of the Upper Disk Speed (N). Figures 3-8 demonstrate the dependency of the extraction efficiency, E, and the overall volumetric mass-transfer coefficients, KLa, on the upper disk speed, N. An increase in E is visible by increasing the upper disk speed to 1400 rpm. Such a behavior is the consequence of an increase in the mixing and turbulence, which controls the present extraction processes. When the disk speed is low, on the other hand, the liquid streams have little chance to disperse fully within each other; hence, the performance capability of the contactor decreased. In addition, an increase in the upper disk speed
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Figure 7. Effect of the upper disk speed on the overall volumetric mass-transfer coefficient of KIW: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 10. Effect of the aqueous flow rate on the extraction efficiency of iodine: disk diameters, d, 0.20m; distance between disks, h, 0.0015 m.
Figure 8. Effect of the upper disk speed on the overall volumetric mass-transfer coefficient of WAK: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 11. Effect of the aqueous flow rate on the extraction efficiency of acetic acid: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 9. Effect of the aqueous flow rate on the extraction efficiency of succinic acid: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 12. Effect of the aqueous flow rate on the overall masstransfer coefficient of BSW: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
increases the overall volumetric mass-transfer coefficients. This behavior may be explained by considering the phenomena associated with liquid-liquid extraction in this new kind of IS contactor. Such a behavior is the consequence of an increase in the shear forces exerted on the phases and the turbulence that lead to an increase in the surface renewal mechanism and hence an increase in the interfacial mass-transfer area. 3.4. Effect of the Liquid Flow Rate. Figures 9-14 demonstrate the dependency of the extraction efficiency and the overall volumetric mass-transfer coefficient, KLa, on the aqueous flow rates. It should be noted that in the present study the organic flow rates were identical with those of the aqueous flow rates. As may be observed from Figures 9-11, an increase in the aqueous flow rates within the range of 0.110-0.300 dm3 min-1 decreases the extraction efficiency but has a definite
effect on the overall volumetric mass-transfer coefficients. This can be explained by noting that, in the high aqueous flow rates, the mean residence time of the phases within the extraction compartment is low. In addition, as may be observed from Figures 12-14, an increase in the aqueous flow rates within the aforementioned range of aqueous flow rates increases the overall mass-transfer coefficients. This behavior can be explained by an increase in the mixing and turbulence due to both the impinging process and the high rate shear forces acting on the phases and a consequent increase in the interfacial mass-transfer area as well as enhancement of the surface renewal mechanism produced by eddies. 3.5. Effect of the Disk Diameter (d) and the Distance between Disks (h). Figures 15-17 demonstrate the effect of the distance between disks, h, on the
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Figure 13. Effect of the aqueous flow rate on the overall masstransfer coefficient of KIW: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 16. Effect of the distance between disks on the extraction efficiency of iodine: disk diameters, d, 0.20 m.
Figure 17. Effect of the distance between disks on the extraction efficiency of acetic acid: disk diameters, d, 0.20 m. Figure 14. Effect of the aqueous flow rate on the overall masstransfer coefficient of WAK: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 18. Effect of the disk diameters on the extraction efficiency of succinic acid: distance between disks, h, 0.0015 m. Figure 15. Effect of the distance between disks on the extraction efficiency of succinic acid: disk diameters, d, 0.20 m.
extraction efficiency. It should be noted that in the present study the distances between disks smaller than 0.0015 m were not considered because of the longer times needed for complete separation of the dispersions than those related to larger distances. As may be observed from Figures 15-17, a decrease in the distance between disks, h, from 0.003 to 0.0015 m increases the extraction efficiency. The latter is due to much higher shear forces acting on the phases as well as an increase in the bulk turbulence. A number of experiments were conducted to obtain the extraction efficiency with various disk diameters. Figures 18-20 demonstrate the dependency of the extraction efficiency on the disk diameters. As may be observed from Figures 18-20, an increase in the disk diameters within the range of 0.15-0.25 m increases the extraction efficiency, but this effect was not significant at the high upper disk speeds for disk diameters larger than 0.20 m.
Figure 19. Effect of the disk diameters on the extraction efficiency of iodine: distance between disks, h, 0.0015 m.
3.6. Effect of IS. As can be observed from the experimental setup, the contactor could be constructed in the two following modes either as an impinging-jets contactor or as a non-IS contactor (another new contactor). In the latter mode, both aqueous and organic solutions were fed, separately, through the lower disk
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Figure 20. Effect of the disk diameters on the extraction efficiency of acetic acid: distance between disks, h, 0.0015 m.
Figure 23. Effect of IS on the extraction rate of iodine: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
Figure 21. Cross section of the disks in the non-IS mode.
Figure 24. Effect of IS on the extraction rate of acetic acid: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
should play roles in the extraction processes:
KLa ) f(For,Faq,νor,νaq,γ,Ds,or,Ds,aq,d,QA,Vc,N) (7)
Figure 22. Effect of IS on the extraction rate of succinic acid: disk diameters, d, 0.20 m; distance between disks, h, 0.0015 m.
without premixing of the aqueous and organic phases. A schematic diagram of the nonimpinging-jets mode is given in Figure 21. Thus, the phases did not collide with those opposite to one another within the extraction compartment. Therefore, the following ratio was defined in order to evaluate the enhancing effect of IS:
where F, ν, γ, d, Vc, and N are the density, kinematic viscosity, interfacial tension, disk diameter, contactor volume, and upper disk speed, respectively. The subscripts or and aq denote organic and aqueous phases, respectively. Ds,or and Ds,aq are the diffusion coefficients of the solutes in organic and aqueous phases, respectively. Equation 7 was transformed into the following groups by using the Buckingham Pi method:
( )( )( )( ) ( )( )( )( )
For Faq2 νaq3 KL a ) J 2 Faq γ QA γ
Eh )
extraction rate in an IS contactor extraction rate in a non-IS contactor
(6)
According to such a definition, IS will be more efficient if Eh > 1. Figures 22-24 demonstrate the effect of IS on the extraction rates, R. The following trends were observed: (1) the IS generally increase the extraction rates and (2) the effect of IS diminished at the higher upper disk speeds for various aqueous flow rates. 3.7. Correlation of the Data. Extraction by an IS technique is extremely complicated, and no model is available to establish a correlation for the experimental data. Thus, dimensional analysis was employed to obtain a relationship between the measured quantities. It is assumed that the following independent variables
Faqνaq3
R5
R1
Ds,or νaq
NFaq2 νaq3 γ2
R6
R2
Ds,aq νaq
dγ νaq2Faq
R3
R7
νor νaq
R4
×
Vcγ3
νaq6 Faq3
R8
(8)
The constant J and the exponents R1-R8 are adjustable parameters that were determined by fitting of the experimental data to the correlation. The overall volumetric mass-transfer coefficients, KLa, were correlated by eq 8 and were applied in dimensional forms. It was found that
KLa (min-1) ) KVc-0.6 QA0.59N0.41
(9)
in units of dm3, dm3 min-1, and min-1 for Vc, QA, and N, respectively, with K values of 0.20, 0.40, and 0.45 for the systems of BSW, KIW, and WAK, respectively. 3.8. Evaluation of Various Kinds of Extractors. The performance of the new extractor in comparison with other contactor types is evaluated on the basis of
Ind. Eng. Chem. Res., Vol. 40, No. 2, 2001 687 Table 1. Overall Volumetric Mass-Transfer Coefficient for Different Types of Contactors chemical systema
contactor type vessel21
agitated agitated vessel21 rotated disk contactor22 rotated disk contactor22 rotated disk contactor23 rotary agitated column22 rotary agitated column22 rotary agitated column22 spray column22 spray column22 spray column22 spray column22 packed column22 packed column22 packed column22 packed column22 packed column22 perforated plate column22 IS2 IS2 IS20 IS contactor (present work) IS contactor (present work) IS contactor (present work)
water(c)-iodine-CCl4(d) sulfate ore(c)-uranium-kerosene(d) water(c)-acetic acid-MIBKb(d) water(c)-acetone-DCDEc(d) water(c)-succinic acid-n- butanol(d) n-hexane(c)-acetone-water(d) toluene(c)-acetone-water(d) water(c)-furfural-toluene(d) water(c)-acetone-benzene(d) water(c)-adipic acid-ether(d) water(c)-acetic acid-benzene(d) water(c)-acetic acid-nitrobenzene(d) CCl4(c)-acetone-water(d) kerosene(c)-acetone-water(d) MIBK(c)-uranyl nitrate-water(d) toluene(c)-diethylamine-water(d) vinyl acetate(c)-acetone-water(d) water(c)-acetaldehyde-vinyl acetate(d) water(c)-iodine-kerosene(d) kerosene(d)-acetic acid-water(c) water-iodine-kerosene water(c)-iodine-kerosene(d) kerosene(d)-acetic acid-water(c) water(c)-succinic acid-n-butanol(d)
KLa × 104 (s-1) 0.16-16.6 2.8-17 20-120 57 63-266 0.15 0.2-1.0 105 8-60 20-70 17.5-63 7-32 7.4-24 5.8-61 14.7-111 5-14.7 7.5-32 28.5 15-2100 500-3000 560-2000d 1187-3975 1364-4456 775-2500
a Direction of extraction is from c f d except for kerosene-acetic acid-water, where extraction is from d f c. The substance in the middle is the extract. c ) continuous phase. d ) dispersed phase. b Methyl isobutyl ketone. c Dichlorodiethyl ether. d This maximum value has been obtained based on k ) 2 × 10-3 m/s and H ) 0.01 m in Tamir’s work.
Table 2. Power Input Requirement for Various Contactors contactor type
power input (kJ/m3 of liquid)
agitated extraction column2 mixer-settler2 IS contactor (present work) IS20 IS extractor2 centrifugal extractor2
0.5-190 150-250 175-250 280 35-1500 850-2600
Tables 1 and 2 which contain data for overall volumetric mass-transfer coefficients, KLa, and power input, respectively. It may be concluded (perhaps not definitely) from these data that the new contactor is superior relative to other contactor types with respect to KLa for nearly identical power inputs. Note that, although the IS contactor developed by Tamir20 may need a shorter time for separation of dispersions (smaller settler), it may also have a lower performance capability for the recommended test systems, such as extraction of succinic acid from its aqueous solution using normal butanol as the solvent. Whether the longer time needed for complete separation of dispersions in the new contactor relative to that of the contactor developed by Tamir20 will be offset by higher performance capability is obviously a question which has to be answered before performing an exact comparison between the new contactor and that developed by Tamir.20 The latter subject is due to pertinent economical problems. 4. Conclusions On the basis of the present investigation, the most important results obtained were as follows: (1) The new extractor was found to be effective in liquid-liquid extraction processes. (2) The extraction efficiency obtained in the present study was high over the range of the liquid flow rates. (3) Data obtained in the present study on the overall volumetric mass-transfer coefficients showed that the new extractor is superior
relative to other conventional contactors with respect to KLa for nearly identical power inputs. (4) The phenomena associated with the application of such a technique in liquid-liquid extraction are rather complicated compared to those that occurred in conventional extractors taking into account the phenomena of drops breakage and coalescence. Acknowledgment The author is grateful to M. Ghafari for his help in the experiments and M. A. Heidari for useful discussion. Nomenclature a ) interfacial mass-transfer area between the phases per unit volume of contactor (m2 m-3) C ) concentration of solutes (kg m-3) d ) disk diameters (m) Ds,aq ) diffusion coefficient of solutes in the aqueous phase (m2 s-1) Ds,or ) diffusion coefficient of solutes in the organic phase (m2 s-1) E ) extraction efficiency Eh ) enhancing effect of impinging streams h ) distance between disks (m) J ) constant, in eq 8 K ) constant, in eq 9 KLa ) overall volumetric mass-transfer coefficients (min-1) N ) upper disk speed (rpm) Q ) volumetric flow rate of the liquid phases (dm3 min-1) R ) extraction rates (kg min-1) Vc ) contactor volume (dm3) Greek Letters R ) adjustable parameters, in eq 8 γ ) interfacial tension (N m-1) ν ) kinematic viscosity (m2 s-1) F ) density (kg m-3) ∆ ) difference operator
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Subscripts A ) aqueous phases aq ) aqueous phases i ) inlet of contactor o ) outlet of contactor or ) organic phases Superscript * ) at equilibrium Abbreviations IS ) impinging streams BSW ) butanol-succinic acid-water KIW ) kerosene-iodine-water WAK ) water-acetic acid-kerosene
Literature Cited (1) Elperin, I. T. Transport Processes in Opposing Jets (gas suspensions); Naukai Tekhnica: Minsk, Russia, 1972 (in Russian). (2) Tamir, A. Impinging Streams Reactors: Fundamentals and Applications; Elsevier: Amsterdam, The Netherlands, 1994. (3) Herskowits, D.; Herskowits, V.; Stephan, K.; Tamir, A. Characterization of a Two-Phase Impinging Jet AbsorbersI. Physical Absorption of CO2 in Water. Chem. Eng. Sci. 1988, 43 (10), 2773. (4) Kleingeld, A. W.; Lorenzen, L.; Botes, F. G. The Development and Modeling of High-Intensity Impinging Streams Jet Reactors for Effective Mass Transfer in Heterogeneous Systems. Chem. Eng. Sci. 1999, 54, 4991. (5) Tamir, A.; Herskowits, D.; Herskowits, V. Impinging-Jet Absorber. Chem. Eng. Process. 1990, 28, 165. (6) Tamir, A.; Herskowits, D.; Herskowits, V.; Stephan, K. TwoImpinging Jets Absorber. Ind. Eng. Chem. Res. 1990, 29, 9 (2), 272. (7) Herskowits, D.; Herskowits, V.; Tamir, A. Desorption of Acetone in a Two-Impinging-Stream Spray Desorber. Chem. Eng. Sci. 1987, 42 (10), 2331. (8) Berman, Y.; Tanklevsky, A.; Oren, Y.; Tamir, A. Modeling and Experimental Studies of SO2 Absorption in Coaxial Cylinders with Impinging Streams, Part I. Chem. Eng. Sci. 2000, 55 (5), 1009. (9) Berman, Y.; Tanklevsky, A.; Oren, Y.; Tamir, A. Modeling and Experimental Studies of SO2 Absorption in Coaxial Cylinders with Impinging Streams, Part II, Chem. Eng. Sci. 2000, 55 (5), 1022. (10) Tamir, A.; Grinholtz, M. Performance of a Continuous Solid-Liquid Two-Impinging Streams (TIS) Reactor: Dissolution
of Solids, Hydrodynamics, Mean Residence Time and Holdup of the Particles. Ind. Eng. Chem. Res. 1987, 26, 726. (11) Kitron, Y.; Tamir, A. Performance of a Coaxial Gas-Solid Two-Impinging-Streams (TIS) Reactor: Hydrodynamics, Residence Time Distribution, and Drying Heat Transfer. Ind. Eng. Chem. Res. 1988, 27, 1760. (12) Berman, Y.; Tamir, A. Experimental Investigation of Phosphate Dust Collection in Impinging Streams (IS). Can. J. Chem. Eng. 1996, 74, 817. (13) Herskowits, D.; Herskowits, V.; Stephan, K.; Tamir, A. Characterization of a Two-Phase Impinging Jet AbsorbersII. Absorption with Chemical Reaction of CO2 in NaOH Solutions. Chem. Eng. Sci. 1990, 45 (5), 1281. (14) Sohrabi, M.; Jamshidi, A. M. Studies on the Behavior and Application of the Continuous Two-Impinging Streams Reactors in Gas-Liquid Reactions. Chem. Technol. Biotechnol. 1997, 69, 415. (15) Sohrabi, M.; Kaghazchi, T.; Yazdani, F. Modeling and the Application of The Continuous Impinging Streams Reactors in Liquid-Liquid Heterogeneous Reactions. Chem. Technol. Biotechnol. 1993, 58, 363. (16) Unger, D. R.; Muzzio, F. J.; Brodkey, R. S. Experimental and Numerical Characterization of Viscous Flow and Mixing in an Impinging Jet Contactor. Can. J. Chem. Eng. 1998, 6, 546. (17) Sievers, M.; Gaddis, E. S.; Vogelpohl, A. Fluid Dynamics in an Impinging-Streams Reactor. Chem. Eng. Process. 1995, 34, 115. (18) Sohrabi, M.; Marvast, M. A. Application of a Continuous Two Impinging Streams Reactor in Solid-Liquid Enzyme reactions. Ind. Eng. Chem. Res. 2000, 39, 1903. (19) Yao, B.; Tamir, A. Evaporative Cooling of Air in Impinging Streams. AIChE J. 1995, 41 (7), 1667. (20) Berman, Y.; Tamir, A. Extraction in Thin Liquid Films Generated by Impinging Streams. AIChE J. 2000, 46 (4), 769. (21) Treybal, R. E. Liquid Extraction; McGraw-Hill Book Co., Inc.: New York, 1963. (22) Laddha, G. S.; Degaleesan, T. E. Transport Phenomena in Liquid Extraction; Tata McGraw-Hill Pub. Co.: New Delhi, India, 1976. (23) Ghalechian, J. S. Evaluation of Liquid-Liquid Extraction Column Performance for Two Chemical Systems. Ph.D. Thesis, University of Bradford, Bradford, U.K., 1996.
Received for review February 28, 2000 Accepted October 18, 2000 IE000279S
