Ind. Eng. Chem. Res. 2002, 41, 4085-4093
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SEPARATIONS Liquid-Liquid Extraction with an Interphase Chemical Reaction in an Air-Driven Two-Impinging-Streams Reactor: Effective Interfacial Area and Overall Mass-Transfer Coefficient Asghar Molaei Dehkordi† Department of Chemical Engineering, Amirkabir University of Technology, P.O. Box 14655-394, Tehran, Iran
The theory of mass transfer accompanied by chemical reaction for the pseudo-first-order heterogeneous liquid-liquid reactions was employed to measure the effective interfacial area in an air-driven two-impinging-streams reactor (ADTISR) with spray nozzles. Experiments have also been conducted on the physical extraction of n-butyl formate into distilled water to measure the overall volumetric mass-transfer coefficient experimentally. The latter has been compared with those obtained from the intercepts of Danckwerts’ plots. The overall volumetric masstransfer coefficients obtained by the physical method enabled us to compare the performance capability of the ADTISR relative to mechanically agitated columns. Furthermore, the effects of various operating parameters such as the air flow rate, solution flow rate, reactor’s dimensions including reactor’s length and diameter, modes of operation, and enhancing effect of impinging streams on the overall volumetric mass-transfer coefficient and the conversion of an aqueous NaOH solution have been investigated. 1. Introduction Liquid-liquid extraction with an interphase chemical reaction is commonly used in the chemical industry. Typical applications of liquid-liquid extraction with a chemical reaction are in the recovery of metals from leach liquors, aromatic nitration, and hydrolysis. In liquid-liquid extraction with an interphase chemical reaction, the two reactive species are present in two different, distinct phases, i.e., aqueous and organic phases. One of the phases is continuous and the other dispersed. The reactive species must, therefore, diffuse to a reaction zone or interface, and the reaction product must diffuse away to the selective phase to allow fresh reactive elements to continue the process. The reaction zone may be in either phase or extend to both phases. In the limit it may reduce to a reaction plane, depending on the reaction type and the mode of contact. The rate of extraction is controlled both by the kinetics of the reaction and by the diffusion characteristics of the systems. However, under certain conditions, a chemical process may be either entirely diffusioncontrolled or entirely kinetically controlled. For a very slow reaction accompanied by high mass-transfer rates, the overall extraction rate is determined by the kinetics of reaction, whereas for a very fast reaction, the rate of diffusion controls the overall rate of the process. The knowledge of a specific interfacial area and masstransfer coefficient is essential for the rational design of a variety of liquid-liquid contactors. The most important practical method of determination of the specific interfacial area is to make use of a chemical †
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reaction occurring in such a contactor. Alkaline hydrolysis of esters is a useful chemical system for the measurement of the interfacial area of a variety of liquidliquid contactors. Ghosh et al.,1 Verma and Sharma,2 Nanda and Sharma,3 Fernandes and Sharma,4 Puranik and Sharma,5 and Chaudhuri et al.6 have used this technique for the measurement of the interfacial area, a, in a variety of liquid-liquid contactors, e.g., packed column, mechanically agitated contactors, spray columns, etc. Under some restrictions, it is also possible to use alkaline hydrolysis of esters to determine both the mass-transfer coefficient and interfacial area of liquid-liquid contactors. Puranik and Sharma5 were the first to report about the use of such a method, for the measurements of the overall mass-transfer coefficient, KL, and the specific interfacial area, a, in a liquid-liquid contactor; later, Verma and Sharma2 and Sarkar et al.7 used the same technique for determining the masstransfer coefficient of packed columns and mechanically agitated columns. In 1956, Carver et al.8 published a patent concerning a limited amount of data on an efficient method and device for contacting fluids by impinging streams (IS). The latter is a unique flow configuration, which was then employed by Elperin9 for gas-solid suspensions and further developed by Tamir for various chemical engineering processes.10 In addition, Mujumdar et al. have conducted extensive investigations on the modeling and applications of the IS technique.11-14 The IS method provides a powerful technique for intensifying transfer processes. The principle of IS is to bring the two streams flowing along the same axis in opposite directions into collision. As the result of such a collision, a relatively narrow zone, called the impingement zone of high
10.1021/ie010750x CCC: $22.00 © 2002 American Chemical Society Published on Web 07/09/2002
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turbulent intensity, is created which offers excellent conditions for intensifying heat- and mass-transfer rates. In this zone, the number of drops per unit volume is the highest and continuously decreases toward the inlet point of streams. At the zone of impingement, drops penetrate into the opposite stream because of their inertia and decelerate until stagnation due to the gas drag force. Afterward, the drops accelerate and penetrate into the original stream, and so forth. Thus, drops perform damped oscillation motions. After several oscillatory motions are performed as such, the drop velocity eventually vanishes before it is withdrawn from the system. The latter might occur even earlier because of either interdroplet collisions or collisions with contactor walls. The IS technique has been successfully applied to the absorption and desorption of gases,15-19 dissolution of solids,20 drying of solids,21-25 dust collection,26 absorption with chemical reactions,27,28 two-liquid-phase reaction,29 mixing,30-33 evaporative cooling of air,34 bioreactions,35,36 and liquid-liquid extraction.37-40 The major objectives of the present investigation were as follows: 1. To determine the effective interfacial area between two immiscible phases in an air-driven two-impingingstreams reactor (ADTISR) by the chemical method. 2. To determine the overall volumetric mass-transfer coefficient, KLa, by the physical method. 3. To determine the overall volumetric mass-transfer coefficient, KLa, from Danckwerts’ plots and compare the latter with those obtained by the physical method. To achieve the above aims, an investigation on the liquid-liquid extraction with a chemical reaction using a n-butyl formate (NBF)-aqueous NaOH solution system and physical extraction of the ester into distilled water, applying an ADTISR with spray nozzles, has been investigated.
of the solute A in the phase B corresponding to inlet and outlet conditions of the contactor, respectively. Note that, in the experiments for the determination of the overall volumetric mass-transfer coefficient, KLa, by the physical method [Ai*] ) [Ao*], which is equal to the solubility of phase A in phase B at the operating conditions. When eq 2 is substituted into eq 1 and [Ai*] ) [Ao*] ) [A*], eq 1 reduces to
2.1. Overall Volumetric Mass-Transfer Coefficient by the Physical Method. If the solubility of a solute A, which is being transferred from a phase A to another phase B, is sufficiently low to assume the properties of the phase B to be constant and if the resistance to mass transfer lies entirely in the phase B (by saturating the phase A with the phase B), the logarithmic mean driving force can be applied to determine the overall volumetric mass-transfer coefficient, KLa. Thus, the following expression can be used to obtain the values of the overall volumetric mass-transfer coefficient:
Q([Ao] - [Ai]) ) KLaVc[∆A]ln
(1)
where [Ao], [Ai], Vc, and [∆A]ln are the outlet concentration of solute A (in this case phase A) in the phase B, inlet concentration of solute A in the phase B, contactor volume, and logarithmic mean concentration driving force of solute A, respectively. The logarithmic mean driving force [∆A]ln normally defined by
[∆A]ln )
([Ai*] - [Ai]) - ([Ao*] - [Ao]) ln
{
[Ai*] - [Ai]
[Ao*] - [Ao]
}
(2)
where [Ai*] and [Ao*] are the equilibrium concentrations
)
(3)
2.2. Effective Interfacial Area by the Chemical Method. In a fast heterogeneous liquid-liquid reaction with the relation
Aor + Baq f Cor + Daq
(4)
in which the component A from a first phase diffuses into a second phase containing B with which it reacts in the same phase, the volumetric extraction rate of component A, which undergoes a pseudo-first-order reaction with a component in the other phase, may be expressed using Danckwerts’ model by the following relation:41
RAa ) a[A*](DAK2[B] + KL2)0.5
(5)
where RAa, a, DA, K2, and KL are the extraction rate of A per unit volume of reactor, interfacial area between the two immiscible phases, diffusion coefficient of A in phase B, second-order rate constant, and overall masstransfer coefficient, respectively. The criterion for a pseudo-first-order reaction is given by
[
1+
2. Theory
(
[A*] - [Ai] Q ln Vc [A*] - [Ao]
KLa )
]
DAK2[B] 2
KL
0.5
1. Figure 12 shows the effect of the partition on the conversion. The following trends are observed: (1) the partition generally reduces the conversion and (2) the effect of IS is diminished at an air flow rate of 110 dm3 min-1 for various liquid flow rates. Based on the observations made during the experiments, this may be explained by considering that at this air flow rate the colliding drops might create thin liquid layers on both sides of the partition that behave like well-mixed vessels; thus, the enhancing effect of IS is diminished. As can be observed from Figure 12, Eh increases again at air flow rates greater than 110 dm3 min-1. This behavior can be explained as follows: as mentioned earlier, for air flow rates higher than 110 dm3 min-1, a large number of drops struck against the reactor walls before reaching the impingement zone and hence did not perform oscillatory motion, which is the key phenomenon in enhancing the performance capability of the TIS. Thus, for air flow rates higher than 110 dm3 min-1, the effect of the fraction of liquid drops that can perform such an oscillatory motion on the conversion is dominant. This fraction of drops is prevented from performing oscillatory motions because of the presence of the partition in the middle of the reaction chamber. Therefore, Eh increases again at air flow rates greater than 110 dm3 min-1. 4.2. Danckwerts’ Plots. NBF was contacted with various concentrations of an aqueous NaOH solution within the range of 0.40-0.75 kmol m-3 to determine the values of the overall volumetric mass-transfer coefficient and the effective interfacial area from Danckwerts’ plots. To satisfy the conditions for a pseudo-firstorder mechanism, lower concentrations of a NaOH
Ind. Eng. Chem. Res., Vol. 41, No. 16, 2002 4091
Figure 13. Danckwerts’ plot of (RAa/[A*])2 vs mean concentration of an aqueous NaOH solution, [B]: reactor length, L, 0.30 m; reactor diameter, d, 0.064 m; symmetric.
Figure 16. Calculated interfacial area vs air flow rate: reactor length, L, 0.06 m; reactor diameter, d, 0.064 m; symmetric. Table 2. Results from Alkaline Hydrolysis of NBF in the ADTISR
Figure 14. Calculated vs experimental overall volumetric masstransfer coefficient, KLa: reactor length, L, 0.30 m; reactor diameter, d, 0.064 m; symmetric.
QA (dm3 min-1)
G (dm3 min-1)
[Bi] (kmol m-3)
L (m)
{1 + (DAK2[B]a2)/ (KLa)2}0.5
1 + [B]/[A*]
0.110 0.110 0.110 0.330 0.330 0.330 0.500 0.500 0.500 0.500 0.500 0.500
70 90 110 70 90 110 70 90 110 70 90 110
0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75
0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.06 0.06 0.06
1.89 1.76 1.71 1.49 1.55 1.69 1.65 1.81 1.92 1.18 1.45 1.59
12.02 11.72 11.37 12.70 12.42 12.02 13.02 12.68 12.35 13.35 12.93 12.61
Table 3. Evaluation of the Performance Capability of Various Reactors
bhemical system
A/O
reactor type
NBF-aqueous 1.66/1 Oldshue NaOH Rushton solution column7,10 NBF-aqueous 1/1 ADTISR NaOH solution
Figure 15. Calculated interfacial area vs aqueous flow rate: reactor length, L, 0.30 m; reactor diameter, d, 0.064 m; symmetric.
solution were used. Figure 13 shows the plot of (RAa/ [A*])2 vs average concentration of the reactive species, [B], with the air and aqueous NaOH solution flow rates as parameters. The individual values of the overall volumetric mass-transfer coefficients and the coefficients obtained from these Danckwerts’ plots are given in Figure 14. As can be noticed from Figure 14, there is a relatively good agreement between the experimental and calculated overall volumetric mass-transfer coefficients obtained from the intercepts of Danckwerts’ plots. However, the corresponding experimental values of the overall volumetric mass-transfer coefficients were generally around 15% lower, as shown in Figure 14. Figures 15 and 16 demonstrate the values of the effective interfacial area calculated from the slopes of Danckwerts’ plots vs the air flow rate. As can be observed from Figures 15 and 16, an increase in the air flow rate within the range studied causes a correspond-
power input RAa × 104 requirement KLa × 104 (kmol (kJ m-3 of liquids) (s-1) m-3 s-1) 0.5-190
250
11.47
300-600
750
45.34
ing increase in the effective interfacial area, which can be expected. Notice that the value of DAK2 at the operating conditions has been reported elsewhere.2,3,7 A number of the results obtained from the experiments are summarized in Table 2. It is clear that within the range studied the assumption of a pseudo-first-order reaction has been held for all of the experiments. 4.3. Evaluation of the Performance Capability of the Reactor. The evaluation of the performance capability of the reactor in comparison with other known reactor types is based on the mass-transfer performance and power input requirement. The latter quantities are summarized in Table 3 that contains the data for the overall volumetric mass-transfer coefficients and the volumetric extraction rates as well as power input requirements. It is clear that the ADTISR has a better performance capability with respect to the overall volumetric mass-transfer coefficient and volumetric extraction rate. However, the ADTISR has a much higher power input requirement. Note that the power input requirement for ADTISR is the sum of the power required for the air flow and the feed pumps. To determine these power inputs, during the experiments,
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the pressure drops across the spray nozzles for both the liquids and air streams were measured. According to the experimental results, the pressure drops across the spray nozzles were as follows: (1) 34.45 kPa at aqueous and organic flow rates of 2 dm3 min-1; (2) 20.67 kPa at an air fow rate of 110 dm3 min-1. As can be observed from the experimental results, the conversion of an aqueous solution decreased at air flow rates higher than 110 dm3 min-1. Therefore, the operation of the reactor for air flow rates higher than 110 dm3 min-1 is neither efficient nor economical. Thus, the power requirement for ADTISR was calculated based on an air flow rate of 110 dm3 min-1. Thus, the total power input requirement was determined as follows:
P′ (W) ) (Qaq + Qor)∆pl + G∆pg
(10)
P (kJ m-3 of liquids) ) P′/(Qaq + Qor)
(11)
where ∆pl and ∆pg are the liquid and air stream pressure drops across the spray nozzles, respectively. It should be added that the experimental results for an aqueous flow rate of 2 dm3 min-1 were excluded because of the lower conversion of an aqueous solution. 5. Conclusions (a) Overall Volumetric Mass-Transfer Coefficient and the Conversion of an Aqueous NaOH Solution. (1) The values of the overall volumetric mass-transfer coefficient and the conversion increase with an increase in the air flow rate within the range of 70-110 dm3 min-1. (2) An increase in the aqueous NaOH solution flow rate over the range of 0.170-1.0 dm3 min-1 results in a decrease in the conversion of an aqueous NaOH solution. Conversely, such an increase in the distilled water flow rate increases the overall volumetric mass-transfer coefficient. (3) The volumetric extraction rate increases with an increase in the overall volumetric mass-transfer coefficient; that is, within the range studied the process was controlled by mass-transfer phenomena. (4) The values of the overall volumetric mass-transfer coefficient calculated from the intercepts of Danckwerts’ plots are in good agreement with those obtained by the physical method. (b) Effective Interfacial Mass-Transfer Area. (1) An increase in the air flow rate within the range of 70-110 dm3 min-1 increases the interfacial area. (2) The values of the interfacial area increase with an increase in both the aqueous and organic solution flow rates. (3) The ADTISR offers higher values of the interfacial area as compared with agitated columns. Acknowledgment The author thanks Mohammad Mehdi Ghafari, Mohammad Mehdi Nouri, and Nourallah Talebzadeh for their help and participation in the experimental work. Nomenclature a ) interfacial area (m2 m-3) [A] ) concentration of NBF in distilled water (kmol m-3)
[A*] ) solubility of NBF in an aqueous NaOH solution (kmol m-3) [Aw] ) solubility of NBF in distilled water (kmol m-3) [B] ) concentration of an aqueous NaOH solution (kmol m-3) d ) reactor diameter (m) DA ) diffusion coefficient of solute A in phase B (m2 s-1) DB ) diffusion coefficient of the reactant (m2 s-1) Eh ) enhancing effect of impinging streams G ) air flow rate (dm3 min-1) I ) ionic strength (kmol m-3) K2 ) second-order rate constant (m3 kmol-1 s-1) KL ) overall mass-transfer coefficient (m s-1) KLa ) overall volumetric mass-transfer coefficient (s-1) Ks ) i+ + i- + iester (m3 kmol-1) L ) reactor length (m) P′ ) power input requirement (W) P ) power input (kJ m-3) p ) pressure (kPa) Q ) volumetric flow rate of the liquid phase (dm3 min-1) RAa ) extraction rate per unit volume of the reactor (kmol s-1 m- 3) Vc ) contactor (reactor) volume (dm3) Xc ) conversion of an aqueous NaOH solution Greek Symbol ∆ ) difference operator Subscripts A ) aqueous phase aq ) aqueous phases g ) air stream i ) inlet of the reactor l ) liquids ln ) logarithmic mean o ) outlet of the reactor or ) organic phases Superscript * ) at equilibrium Abbreviations ADTISR ) air-driven two-impinging-streams reactor NBF ) n-butyl formate IS ) impinging streams SS ) stainless steel TIS ) two impinging streams
Literature Cited (1) Ghosh, B.; Mukherjee, D. C.; Bhattacharjee, S.; Chaudhuri, B. Alkaline Hydrolysis of Isoamylformate: Effect of Dissolved Electrolytes on Kinetics. Can. J. Chem. Eng. 2001, 79, 148. (2) Verma, R. P.; Sharma, M. M. Mass Transfer in Packed Liquid-Liquid Extraction Columns. Chem. Eng. Sci. 1975, 30, 279. (3) Nanda, A. K.; Sharma, M. M. Effective Interfacial Area in Liquid-Liquid Extraction. Chem. Eng. Sci. 1966, 21, 707. (4) Fernandes, J. B.; Sharma, M. M. Effective Interfacial Area in Agitated Liquid-Liquid Contactor. Chem. Eng. Sci. 1967, 22, 1267. (5) Puranik, S. A.; Sharma, M. M. Effective Interfacial Area in a Packed Liquid Extraction Column. Chem. Eng. Sci. 1970, 25, 257. (6) Chaudhuri, B.; Bhattacharjee, S.; Dutta, B. K. Kinetics of Alkaline Hydrolysis of 2-Ethylbutylformate. Can. J. Chem. Eng. 1996, 74, 806. (7) Sarkar, S.; Mumford, C. J.; Phillips, C. Liquid-Liquid Extraction with Interphase Chemical Reaction in Agitated Columns. 2. Hydrodynamics and Mass Transfer in Rotating Disk and Oldshue Rushton Contactors. Ind. Eng. Chem. Process Des. Dev. 1980, 19, 672.
Ind. Eng. Chem. Res., Vol. 41, No. 16, 2002 4093 (8) Carver, J. A.; Plains, S.; Rollman, W. F. Method and Apparatus for Mixing and Contacting Fluids. U.S. Patent 2751335, June 19, 1956. Application February 1, 1951. (9) Elperin, I. T. Heat and Mass Transfer in Opposing Currents. J. Eng. Phys. 1961, 6, 62 (in Russian). (10) Tamir, A. Impinging Streams Reactors: Fundamentals and Applications; Elsevier: Amsterdam, The Netherlands, 1994. (11) Hosseinalipour, S. M.; Mujumdar, A. S. Flow and Thermal Characteristics of Steady Two-Dimensional Confined Laminar Opposing Jets: part I. Equal Jets. Int. Commun. Heat Mass Transfer 1997, 24, 27. (12) Hosseinalipour, S. M.; Mujumdar, A. S. Flow and Thermal Characteristics of Steady Two-Dimensional Confined Laminar Opposing Jets: part II. Unequal Jets. Int. Commun. Heat Mass Transfer 1997, 24, 39. (13) Hosseinalipour, S. M.; Mujumdar, A. S. Comparative Evaluation of Different Turbulence Models for Confined Impinging and Opposing Jet Flows. Num. Heat Transfer, Part A 1995, 28, 647. (14) Seyedein, S. H.; Hasan, M.; Mujumdar, A. S. Modeling of a Single Confined Turbulent Slot Jet Impingement Using Various k- Turbulence Models. Appl. Math. Model. 1994, 18, 526. (15) Herskowits, D.; Herskowits, V.; Tamir, A. Desorption of Acetone in a Two-Impinging-Stream Spray Desorber. Chem. Eng. Sci. 1987, 42 (10), 2331. (16) Tamir, A.; Herskowits, D.; Herskowits, V. Impinging-Jets Absorber. Chem. Eng. Process. 1990, 28, 165. (17) Tamir, A.; Herskowits, D.; Herskowits, V.; Stephan, K. Two-Impinging Jets Absorber. Ind. Eng. Chem. Res. 1990, 29 (2), 272. (18) 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. (19) 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. (20) 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. (21) 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. (22) Kudra, T.; Mujumdar, A. S. Impinging Stream Dryers for Particles and Pastes. Drying Technol. 1989, 7, 219. (23) Kudra, T.; Mujumdar, A. S. Impinging Stream Dryers. In Handbook of Industrial Drying, 2nd ed.; Mujumdar, A. S., Ed.; Marcel Dekker: New York, 1995. (24) Kudra, T.; Mujumdar, A. S.; Meltser, V. L. Impinging Stream Dryers: Principles, Practice and Potential. Drying of Solids; Sarita Prakashan: Meerut, India, 1991. (25) Hosseinalipour, S. M.; Mujumdar, A. S. Superheated Steam Drying of a Single Particle in an Impinging Streams Dryer. Drying Technol. 1995, 13, 1279. (26) Berman, Y.; Tamir, A. Experimental Investigation of
Phosphate Dust Collection in Impinging Streams (IS). Can. J. Chem. Eng. 1996, 74, 817. (27) 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. (28) 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. (29) 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. (30) 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, 76, 546. (31) Devahastin, S.; Mujumdar, A. S. A Numerical Study of Flow and Mixing Characteristics of Laminar Confined Impinging Streams. Chem. Eng. J. 2002, 85 (2-3), 215. (32) Devahastin, S.; Mujumdar, A. S. A Numerical Study of Mixing in a Novel Impinging Stream Inline Mixer. Chem. Eng. Process. 2001, 40 (5), 459. (33) Devahastin, S.; Mujumdar, A. S. A Study of Turbulent Mixing of Confined Impinging Streams Using a New Composite Turbulence Model. Ind. Eng. Chem. Res. 2001, 40, 4998. (34) Yao, B.; Berman, Y.; Tamir, A. Evaporative Cooling of Air in Impinging Streams. AIChE J. 1995, 41 (7), 1667. (35) Sievers, M.; Gaddis, E. S.; Vogelpohl, A. Fluid Dynamics in an Impinging-Streams Reactor. Chem. Eng. Process. 1995, 34, 115. (36) 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. (37) Berman, Y.; Tamir, A. Extraction in Thin Liquid Films Generated by Impinging Streams. AIChE J. 2000, 46, 769. (38) Dehkordi, A. M.; Kaghazchi, T.; Sohrabi, M. Application of an Air-Operated Two Impinging Streams Extractor in LiquidLiquid Extraction and Comparison with Other Contactor Types. Can. J. Chem. Eng. 2001, 79, 227. (39) Dehkordi, A. M. Novel Type of Impinging Streams Contactor for Liquid-Liquid Extraction. Ind. Eng. Chem. Res. 2001, 40 (2), 681. (40) Dehkordi, A. M. A Novel Two-Impinging-Jets Reactor for Copper Extraction and Stripping Processes. Chem. Eng. J. 2002, 87 (2), 227. (41) Danckwerts, P. V. Gas-Liquid Reactions; McGraw-Hill: New York, 1970. (42) Alwan, S.; Hiraoka, S.; Yamada, I. Extraction Rate of n-Amyl Acetate with Alkaline Hydrolysis in Aqueous Phase. Chem. Eng. Commun. 1983, 22, 317. (43) Laddha, G. S.; Degaleesan, T. E. Transport Phenomena in Liquid Extraction; Tata McGraw-Hill Pubs. Co.: New Delhi, India, 1976.
Received for review September 10, 2001 Accepted March 13, 2002 IE010750X
