ANL-80-82 ANL-80-82 FUEL CYCLE APPLIED TECHNOLOGY ...

ANL-80-82 ANL-80-82

CHEMICAL ENGINEERING DIVISION

FUEL CYCLE APPLIED TECHNOLOGYQUARTERLY PROGRESS REPORT

July September 1979

by

M. J. Steindler, G. J. Bernstein,R. A. Leonard, and A. A. Ziegler

APPLIED TECHNOLOGY

APPLIED TECHNOLOGY

Any Further Distribution by any Holder of that Document or of OtherData Therein to Third Parties Representing Foreign Interests, ForeignGovernments. Foreign Companies and Foreign Subsidiaries or ForeignDivisions of U. S. Companies Should Be Coordinated with the Director,Nuclear Power Development Division, Department of Energy. (U83-861

ARGONNE NATIONAL LABORATORY, ARGONNE, ILLINOIS

Prepared for the U. S. DEPARTMENT OF ENERGYunder Contract W-31-109-Eng-38

The facilities of Argonne National Laboratory are owned by the United States Government. Under theterms of a contract (W-31-109-Eng-38) among the U. S. Department of Energy, Argonne UniversitiesAssociation and The University of Chicago, the University employs the staff and operates the Laboratory inaccordance with policies and programs formulated, approved and reviewed by the Association.

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NOTICE

This report was prepared as an account of work sponsored byan agency of the United States Government. Neither the UnitedStates Government or any agency thereof, nor any of theiremployees, make any warranty, express or implied, or assumeany legal liability or responsibility for the accuracy, com-pleteness, or usefulness of any information, apparatus,product, or process disclosed, or represent that its use wouldnot infringe privately owned rights. Reference herein to anyspecific commercial product, process, or service by trade name,mark, manufacturer, or otherwise, does not necessarily con-stitute or imply its endorsement, recommendation, or favoringby the United States Government or any agency thereof. Theviews and opinions of authors expressed herein do notnecessarily state or reflect those of the United States Govern-ment or any agency thereof.

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Price: Printed Copy $5.00

Distribution Category:Applied Technology (UC-86)

ANL-80-82

ARGONNE NATIONAL LABORATORY9700 South Cass Avenue

Argonne, Illinois 60439



July--September 1979

by


September 1980

Previous reports in this series

ANL-80-77 October-December 1978ANL-80-79 January-March 1979ANL-80-81 April-June 1979

TABLE OF CONTENTS

Page

ABSTRACT 1

SUMMARY 1

I. DEVELOPMENT OF ADVANCED SOLVENT-EXTRACTION TECHNIQUES 2

A. Introduction 2

B. Development of a 0.5 Mg/d Centrifugal Contactor 2

C. Testing of 2-cm-ID Centrifugal Contactors 2

D. Design of a 4-cm-ID Centrifugal Contactor 3

E. Extension of Dispersion-Band Model 3

F. Development of a 10 Mg/d Centrifugal Contactor 3

REFERENCES 10

iii

LIST OF FIGURES

No. Title Page

1. Overall View of 25-cm-ID Contactor 4

2. Effect of Rotor Speed on 25-cm-ID Contactor Capacity 5

3. Effect of Flow Rate on Acceptable Aqueous Weir Air Pressurefor Organic-Continuous Operation 6

4. Effect of Flow Rate and Rotor Speed on the Liquid Level inthe Couette (Annular) Mixing Zone 8

5. Correlation of Mixing Power with the Operating Parameters ofthe 25-cm-ID Contactor 9

iv



July--September 1979

by


ABSTRACT

Work on the application of annular centrifugal contactors tosolvent extraction included hydraulic testing of a 25-cm-IDcontactor, fabrication of a 9-cm-ID contactor, and extension of thedispersion band model to allow the optimal organic weir radius forcentrifugal contactors to be determined.

SUMMARY

Development of Advanced Solvent Extraction Techniques

Hydraulic testing of the 25-cm-ID contactor (10 Mg/d) was completed, andthe unit was shipped to SRI for extraction efficiency tests. The hydraulicperformance tests confirm and extend the correlations and models developedearlier for the 2-cm-ID and 9-cm-ID contactors.

A second 0.5-Mg/d (9-cm-ID) contactor (the M-2 contactor) has beenfabricated and is ready for installation. Results of multistage tests using2-cm-ID contactors were summarized in a topical report and a paper forpublication. The dispersion-band model was extended to allow the optimalorganic weir radius for centrifugal contactors to be determined.

1

2

I. DEVELOPMENT OF ADVANCED SOLVENT-EXTRACT ION TECHNIQUES

(G. J. Bernstein, R. A. Leonard, A. A. Ziegler, and

E. M. Rudnick*)

A. Introduction

Efforts are currently being devoted to the design, construction, andtesting of several sizes of annular centrifugal contactors t for use in

solvent-extraction reprocessing of nuclear reactor fuel. Miniature centrifugalcontactors (2-cm-ID rotor) in single-stage and multistage construction havebeen tested for evaluation of their hydraulic characteristics and for use in

solvent-extraction flowsheets.

A larger contactor (9-cm-ID rotor) has been tested for hydraulicperformance as a candidate for reprocessing fuel at 0.5 Mg/d in the Consoli-dated Fuel Reprocessing Program. A larger unit (12-cm-ID rotor) has beenfabricated and will be tested for broader application in the same program.A large annular contactor (25-cm-ID rotor) was tested recently for applicationin a facility for reprocessing light water reactor fuel at a rate of 10 Mg/d.

B. Development of a 0.5 Mg/d Centrifugal Contactor

A second 0.5 Mg/d centrifugal contactor (the M-2 contactor) with a 12-cm-ID rotor was fabricated and is being mounted in the test facility. This unitshould have a maximum throughput twice that of the first contactor, whichhad a 9-cm-ID rotor.

C. Testing of 2-cm-ID Centrifugal Contactors

Final hydraulic tests of the 2-cm-ID contactors were completed, andthe first draft of a topical report, Design and Operation of LaboratoryAnnular Centrifugal Contactors, was written. Based on this report, a paper,Annular Centrifugal Contactors for Solvent Extraction, was prepared. Thepaper will be presented at the Symposium on Separation Science and Technologyfor Energy Application, Gatlinburg, Tennessee, October 30 - November 2, 1979,and will subsequently be published in Separation Science and Technology.

Summer Student.tin the ANL annular centrifugal contactor, the two phases are fed into the

annulus between the vertical rotor which is spinning and the stationary casing.Here the two phases are mixed by skin friction (Couette mixing) as they flowdown the annulus. Radial vanes in the bottom of the casing then direct themixture through the rotor orifice into the bottom of the hollow rotor. Withinthe rotor, the organic and aqueous phases are separated under centrifugalforce, and the separated phases are directed by means of circular weirs toappropriate discharge ports at the top of the rotor. Multistage counter-current extraction is achieved by connecting individual contactors in series.

3

The 2-cm-ID contactors had relatively poor performance when operated atlow organic-to-aqueous (0/A) flow ratios. This has been attributed to thefact that organic-continuous emulsions persist in the annulus even when thevolume of the organic phase is low in comparison to the volume of dispersedaqueous phase. In such emulsions, with the volume of the dispersed phasemore than twice the volume of the continuous phase, the viscosity of theemulsion increases, and flow into the rotor orifice is inhibited. Thiscauses backup of emulsion in the annulus and contamination of the organiceffluent stream. Similar disturbances were not found in the operation of the9-cm-ID and 25-cm-ID contactors, presumably because their larger dimensionspermit transition from organic-continuous to aqueous-continuous emulsionsbefore the emulsion viscosity can increase significantly.

D. Design of a 4-cm-ID Centrifugal Contactor

A 4-cm-ID contactor is being designed to help determine whether thedifficulties encountered in the operation of the 2-cm-TD contactors wereprimarily due to their small size. If hydraulic performance of the 4-cm-IDcontactor is good at low 0/A ratios, it can be used to evaluate (betterthan by the use of 2-cm-ID contactors) the hydraulic performance ofproduction-size multistage annular centrifugal contactors.

This unit will also be used to evaluate contactor performance when threeliquid phases (two organic phases) are present, such as can occur inThorex processes.

E. Extension of Dispersion-Band Model

By extending the dispersion-band model developed earlier [STEINDLER-1979A1, a method for determining the optimum organic weir radius was developed.It was shown that the optimum ratio of the organic weir radius to the aqueousunderflow radius is 0.455. With this ratio, the rotor would have itsmaximum separating capacity for any rotor speed. The 9-cm-ID, 12-cm-ID,and 25-cm-ID rotors have ratios of 0.506, 0.500, and 0.415, respectively.Thus, the throughput of the 9-cm-ID and 12-cm-ID contactors would each beincreased 6% with a slightly smaller organic weir radius. For the 25-cm-IDcontactor, the organic weir radius could be increased somewhat without loss

of contactor capacity.

F. Development of a 10 Mg/d Centrifugal Contactor

Under a program funded by Savannah River Laboratory (SRL), an annularcentrifugal contactor with a 25-cm-ID rotor was built for evaluation of its

operating characteristics . Following the dynamic balancing operations

described in [STEINDLER-1979B ], the contactor was tested for hydraulic

performance. The tests confirm and extend the models developed for thesmaller 2-cm-ID and 9-cm-IC contactors. A 120 L/min (32 gpm) throughput wasdemonstrated, which satisfies the 30 gpm flow rate specified for the A-bankof the SRI Purex flow sheet on a 10 Mg/d scale. The 25-cm-ID contactor in

the test stand is shown in Fig. 1.

4

Fig. 1. Overall View of 25-cm-ID ContactorANL Neg. No. 308-79-649

5

Hydraulic performance tests on the 25-cm-ID unit are reported below infive parts. First, the liquid rise over the aqueous weir was tested by themethod employed by [LEONARD-1979B] in determining the rise of liquid over acircular weir in a centrifugal field. Based on tests of the 9-cm-ID unit, a0* value of 0.333 was found to be appropriate for the correlation. For the25-cm-TD unit, 0 seems to be about 0.667. The original correlation [WEBSTER]had a 0 of 1.0.

Second, the dimensionless dispersion number, Npi , as defined and testedby [LEONARD-1979A] indicates that throughput should be proportional to rotorspeed for a given contactor. This relationship was tested at rotor speedsfrom 600 to 1450 rpm, as shown in Fig. 2, and is seen to work well. Thedispersion number calculated from the line through the experimental data is8.3 x 10-4.

500 1000 1500 2000 2500

ROTOR SPEED, rpm

Fig. 2. Effect of Rotor Speed on 25-cm-IDContactor Capacity. A: 0.3M HNO3.0: 30% TBP in nDD. 0/A = 1.0.

The general formula for the weir coefficient, k, is

A2k = k exp[- (k f I-)2/3 (q/)1/31* bn

where the term, 0, is added to compensate for the fact that in the ANL rotordesign, the radial vanes in the weir area extend from the rotor wall only to theedge of the weir, rather than to the rotor axis as they do in the SRL design.

6

Third, the dispersion-band model [STEINDLER-1979A] uses the correlationfor liquid rise over a circular weir and the dispersion number to give therange of acceptable aqueous weir air pressures as a function of flow rate(Fig. 3).

Tests were done at various 0/A ratios and rotor speeds. Results of onesuch test are shown in Fig. 3. The dispersion number is about 8.8 x 10-4,which is close to that determined from Fig. 3. Other dispersion-band modeltests gave dispersion numbers of 8.0 x 10 -4 to 10.1 x 10-4 . In comparison,the 2-cm-ID contactor with a capacity of 0.20 L/min has a dispersion numberof 8.4 x 10-4 . The good agreement between experimental weir air pressuresgiving satisfactory operation and those predicted by the model shows theusefulness of the dispersion number in scaling up or scaling down contactordesign.

7 rI 1

PHASECONTAMINATION --

70

o <I01-2x >2

1111111 40 80 120 160

FLOW RATE, L/min .

Fig. 3. Effect of Flow Rate on AcceptableAqueous Weir Air Pressure forOrganic-Continuous Operation.25-cm-ID Contactor. A: 0.3M HNO3.0: 30% TBP in nDD. 0/A = 1.0.Rotor speed = 1200 rpm.

cy

00

Hs = additional liquid head needed if the rotor is not fully pumping,i.e., Hs > 0, m

bo - length of separating zone, m

g = gravitational acceleration, m/s2

7

Fourth, liquid level in the Couette (annular) mixing zone was measuredas a function of throughput at various rotor speeds. The results arepresented in Fig. 4 along with the theoretical curves. The theory representsthe sum of two contributions to the liquid height in the Couette zone. Onepart is an empirical correlation for the fully pumping rotor, which gives aliquid height proportional to rotor speed [STEINDLER-1979A]. The other isthe additional head (height) needed to drive the liquid through the rotororifice when the rotor is running so slowly that it is not maintaining itsfull pumping capacity. This additional head is given by:

(02H = b o - 2g (r 2 - r2)s o t

where

r o = radius of surface of liquid flowing over the organic weir, m

r t = radius of rotor inlet, m

w = rotor speed, radians/s

The good fit of this model with the experimental data indicates thevalidity of the assumption made--namely, that the liquid flows into the rotoras a result of upward pressure on the fluid below the rotor so that nocircular weir coefficient or liquid rise over the weir is needed at the rotor

inlet.

A sharp rise in liquid level in the annulus at low rotor speeds is dueto the fact that at those speeds, the rotor is not pumping well enough tokeep the zone in the rotor immediately above the inlet free of liquid.Consequently, the liquid level in the annulus must rise to provide theadditional pressure needed to overcome the back pressure of the liquid above

the rotor inlet.

One other aspect of the liquid level data is that, for a fully pumpingrotor, the liquid height in the annulus seems to be proportional to therotor diameter to the -1.5 power. This relationship is based upon acomparison of 25-cm-ID contactor operating data with that for 2-cm-ID and

9-cm-ID units.

Fifth, the mixing power required in the Couette zone was measured and

correlated with rotor speed (to) and height in the Couette mixing zone (H),

as shown in Fig. 5. The theoretical curve calculated from [STEINDLER-1979A]is also plotted in this figure and shows good agreement of the theory with

the experimental results.

At the conclusion of the above tests, the contactor was cleaned anddismantled and shipped to Savannah River Laboratory for further testing. Inthe testing program at ANL, the contactor could not be tested to the maximum

8

350

300

E 250

-GA

"G 200

c

▪

,

a= 150t;

=D

2E

• 100

50

00 FLOW RATE

L/mhA. 30

0 x6090

Solid Curves Are Based On

Semitheoretical Correlation

90 L/min

'53

0 60 L/min0 0

30 L/min

A A

0 1 1 i 1 i 1 i 1

600 BOO 1000 MO MO 1600 1800

ROTOR SPEED, rpm

Fig. 4. Effect of Flow Rate and Rotor Speed onthe Liquid Level in the Couette (Annular)

Mixing Zone. 25-cm-ID Contactor.A: 0.3M HNO 3 . 0: 30% TBP in nDD.0/A = 1.0.

capacity of a 25-cm-1D rotor. The solution pumping system had a capacity of60 L/min for each phase, restricting the range of 0/A ratios and totalthroughput that could be tested. Most of the hydraulic tests were performedat 1200 rpm or less; the maximum capacity of the contactor was 120 L/minat 0/A = 1. As built, the rotor has an operating critical speed of 1450 rpmand so throughputs above 120 L/min can be tested at SRL. Extrapolations ofthe ANL data indicate that the contactor should have a capacity of about135 L/min at 1450 rpm and a capacity of about 165 L/min at 1750 rpm (which isthe usual operating speed of a nominal 1800 rpm motor). A critical speedsafely greater than 1750 rpm could be achieved with the same size rotor if itis built with a larger-diameter shaft.

It is expected that SRL will not only extend the hydraulic capacity tests,but will also conduct uranium extraction efficiency tests on the contactor.

1[111111ROTOR SPEED

rpm O 600O 900A 12003 1450

00 I 1111(1111111

5 10 15

w275 fi x KO -275• ,

9

Fig. 5. Correlation of Mixing Power with the OperatingParameters of the 25-cm-ID Contactor. A: 0.3MHNO 3 . 0: 30% TBP in nDD. 0/A = 1.0.

10

REFERENCES

Leonard-1979AR. A. Leonard, G. J. Bernstein, R. H. Pelto, and A. A. Ziegler,Liquid-Liquid Dispersion in Turbulent Couette Flow, paper presentedat 72nd Annual Meeting of the AIChE, San Francisco, Calif., November25-29, 1979.

Leonard-1979BR. A. Leonard, R. H. Pelto, A. A. Ziegler, and G. J. Bernstein,Flow Over Circular Weirs in a Centrifugal Field, Can. J. Chem. Eng.(in press).

Steindler -1979AM. J. Steindler et al., Chemical Engineering Division Fuel. CycleApplied Technology, Quarterly Progress Report, January-March 1979,Argonne National Laboratory Report ANL-80-79.

Steindler -1979BM. J. Steindler et al., Chemical Engineering Division Fuel CycleApplied Technology, Quarterly Progress Report, April-June 1979,Argonne National Laboratory Report ANL-80-81.

Webster

D. S. Webster, C. L. Williamson, and J. F. Ward, Flow Characteristicsof a Circular Weir in a Centrifugal Field, USAEC Report DP-371,Savannah River, South Carolina (1961).

Internal:

W. E. MasseyL. BurrisR. A. LeonardA. MeltonM. J. Steindler (10)L. E. Trevorrow

D. S. WebsterA. A. ZieglerANL Contract FileANL Libraries (2)TIS Files (6)

External:

11

Distribution for ANLr80-82

DOE-TIC, for distribution per UC-86 (89)Manager, Chicago Operations and Regional Office, DOEChief, Office of Patent Counsel, DOE-COROS. A. Mann, DOE-COROArgonne Universities Association:

PresidentJ. T. Banchero, U. Notre DameP. W. Gilles, U. KansasR. I. Newman, Fripp Island, S. C.

T. W. Ambrose, Battelle Pacific Northwest Lab.G. S. Barney, Rockwell Hanford OperationsR. C. Baxter, Allied-General Nuclear Services, BarnwellB. C. Blanke, USDOE-DA, Miamisburg, 0.D. Bowersox, Los Alamos Scientific Lab.C. L. Brown, Battelle Pacific Northwest Lab.L. L. Burger, Battelle Pacific Northwest Lab.W. T. Cave, Mound Lab.J. L. Crandall, Savannah River Lab.R. Cunningham, Nuclear Materials Safety and Safeguards, USNRCB. R. Dickey, Allied Chemical Corp., Idaho FallsO. J. Elgert, Richland Operations Office, USDOE (2)D. Ferguson, Oak Ridge National Lab.C. W. Francis, Oak Ridge National Lab.R. G. Geier, Rockwell Hanford OperationsS. G. Harbinson, San Francisco Operations Office, USDOEM. Harwell, Battelle Pacific Northwest Lab.T. B. Hindman, Jr., USDOE-SRC. J. Kershner, Mound Lab.W. H. Lewis, Nuclear Fuel Services, RockvilleLos Alamos Scientific Lab., DirectorA. L. Lotts, Oak Ridge National Lab.R. Y. Lowrey, Albuquerque Operations Office, USDOE (2)R. Maher, Savannah River PlantJ. C. Mailen, Oak Ridge National Lab.M. L. Matthews, Nuclear Power Development, USDOED. L. McIntosh, Savannah River Lab.W. H. McVey, USDOE-NPDR. E. Meyer, Oak Ridge National Lab.D. A. Orth, Savannah River PlantB. Paige, Allied Chemical Corp., Idaho FallsJ. H. Pashley, Oak Ridge Gaseous Diffusion PlantH. Postma, Oak Ridge National Lab.

12

G. L. Ritter, Exxon Nuclear Corp., Richland

H. E. Roser, Albuquerque Operations Office, USDOE

K. J. Schneider, Battelle Pacific Northwest Lab.K. Street, Lawrence Livermore Lab.USDOE Div. of Nuclear Power Development, Nuclear Fuel Cycle Programs Br.

USDOE Office of Basic Energy Sciences

H. H. Van Tuyl, Battelle Pacific Northwest Lab.V. C. A. Vaughn, Oak Ridge National Lab.

E. E. Voiland, General Electric Co., Morris, Ill.B. L. Vondra, Oak Ridge National Lab.

C. D. Watson, Oak Ridge National Lab.L. L. Wendell, Battelle Pacific Northwest Lab.J. B. Whitsett, Idaho Operations Office, USDOEW. J. Wilcox, Oak Ridge Gaseous Diffusion Plant

A. K. Williams, Allied-General Nuclear Services, BarnwellD. D. Wodrich, Rockwell Hanford Operations

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ANL-80-82 ANL-80-82 FUEL CYCLE APPLIED TECHNOLOGY ...

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