ORNL-TM-3140 by Jon Morrow

This report was prepared as a n account of work sponsored Dy the United States Governnwit. Neither the United States nor the United States Atomic 4tomic Energy Comrnission, nor any of their employees, nor any of thelr contractors, implied, or subcontractors, or their employees. makes any warranty, express or Implied, assumes any legal liability or responsibility for t h e accuracy, r~mpleteness or usefulness of any information, apparatus, product or process disclosed, or represents that i t s use would not infringe privately owned rights. I

ORNL-TM-3140 C o n t r a c t N o . W-7405-eng-26 CKEMICAL TECHXOLOGY D I V I S I O N

E N G I N E E R I N G DEVELOPMENT S T U D I E S FOR MOLTEN-SALT BREEDER REACTOR P R O C E S S I N G NO. 5

L. E. M c N e e s e

OCTOBER 19711

OAK R I D G E NATIONAL LABORATORY Oak R i d g e , Tennessee o p e r a t e d by UNION C A R B I D E COFSORATION f o r the U . S . ATOMIC ENERGY COMMISSION

3 44.56 0 3 3 5 2 8 7 9

Reports p r e v i o u s l y i s s u e d i n t h i s series are as f o l l o w s :

ORNL--)+235

OKNL-4364 ORNL- b 365 ORNL-4 366

ORNL-TM-3053

ORNL-TM-33.37

O , p i l ~ -TM- 3138

ORNL-TM-3139

P e r i o d ending December 1.967 l e r i o d end-ing March 1968 P e r i o d ending June 1968 Period ending September 1.968 P e r i o d ending December 1968 P e r i o d ending March 1.969 Period endi.ng June 1969 Period. ending September 1969

iii CONTENTS

Page

S U M I v I A R I E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. INTRODUCTION

..........................

. . Equilibrium Data and Concentrations . . . . . . . . . . . . Removal of Rare Earths and Thorium from LiCl . . . . . . . . Conceptual Process Flowsheet and Mathematical Analysis . . . Calculated Rare-Earth Removal Times . . . . . . . . . . . . Effect of Rare-Earth Removal Time on Breeding Ratio . . . .

2. RARE-EARTH NENOVAL USING THE METAL-TRANSFER PROCESS

2.1

2.2

2.3

2.4 2.5

2.6 Miscellaneous Points Related to the Metal-Transfer Process 3. PROTACTINIUM ISOLATION USING FLUORINATION--REDUCTIVE EXTRACTION 3.1

Proposed Flowsheet for Isolating Protactinium by Fluorination--Reductive Extraction

......... 3.2 Calculated System Performance . . . . . . . AXIAL DISPERSION IN OPEN BUBBLE COLUMNS .... 4.1 Experimental Technique and Equipment . . . .

...... ...... ...... ...... Experimentally Determined Dispersion Coefficients . . . I

4.2

.. ..

5. SEMICONTINUOUS REDUCTIVE EXTRACTIOI’T EXPERIMENTS IN A MILD-STEEL FACILITY..

......

5 . 1 Hydrodynamic Run HR-6

.............. ..................

...

5.2 Hydrodynamic Runs HR-7 and IIR-8;Tests for Obstructions < .

6. SIf4ULATION OF 6.2

THE: FLOW CONTROL SYSTEMS FOR THE REDUCTIVE EXTFiAC-

. . . . . . . . . . . . . . . . .. . . . . . . . Analog Simulation of Jackleg and Extraction Column ... Digital Simulation of Salt Flow Control System, Jackleg, and Extraction Column . . . . . . . . . . . . . . . . . . .

TIONFACILITY

6.1

7. CALIBRATION OF

ORIFICE--HEAD POT FLOWMETER WITH MOLTEN SALT

.......................... 7.1 Data from Steady-State low Experiments . . . . . . . . . . 7.2 Data from Transient Flow Experiments . . . . . . . . . . . ELECTROLYTIC CELL DEVELOPMENT: STATIC CELL EXPERIMmTS ... AND BISMUTH

2 2

5 9

17 22

26 27

36 37

46 56

56 58

CONTENTS (Continued)

ELECTROLYTIC CELL DEVELOPMENT :

9.2

9.3

F O I W T I O N OF FROZEN FILMS WITH

..................... Mathematical Analysis . . . . . . . . . . . . . . . . . Experimental Equipment . . . . . . . . . . . . . . . . . Expected Mode of Operation . . . . . . . . . . . . . . .

AQUEOUS ELECTROLYTES

9.1

Page

10. DEVELOPMENT OF A BISMUTH--bl’3bTEIV

SALT INTERFACE DETECTOR

...

10.1 Testing and Modification of Electronic Circuit P r i m to Installation

11.

1.2.

13.

...................... 10.2 Fabrication of S i g h t Tube . . . . . . . . . . . . . . . CONTIPJUOTJS SALT PUXIFICATION . . . . . . . . . . . . . . . . . MSRE DISTILLATION EXPERIMENT . . . . . . . . . . . . . . . . . RECOVERY OF 7Li FROM 7 Li--BISMUTH--RARE-EARTH DISTILLATION.

SOLUTIONS BY

........................ 13.1 Mathematical Analysis . . . . . . . . . . . . . . . . . 13.2 Cal-culated Results . . . . . . . . . . . . . . . . . . . 11.1. PEiEVENTiON OF AXIAL DISPERSION IN PACKED COLUMNS . . . . . . .

69 71

74 76 77 79

88 a8 93

15. HYDRODYNAMICS OF PACKED COLUMN OPERATION WITH HIGH-DENSITY FLTJIDS 102

15.1 15.2

15.3

. Pressure Drop Across the Column . . Dispersed-Phase Holdup . . . . . . . Correlation of Fl-ooding Rates . . . Experimental Technique and Results

.......... .......... .......... ..........

15.4 15.5 Prediction of Molten-Saltf3ismuth Flooding ’iiates in Packed

........................ ..........................

Columns

16. REFERENCES

103

104

112 113

116 118

v SUMVAR IES RARE-EARTH REMOVAL USING THE METAL-TRANSFER PROCESS

We have d e v i s e d a new p r o c e s s , c a l l e d t h e m e t a l - t r a n s f e r p r o c e s s , f o r removing r a r e - e a r t h f i s s i o n p r o d u c t s from t h e f u e l s a l t o f a s i n g l e I n t h e p r o c e s s , bismuth c o n t a i n i n g thorium and l i t h i u m i s

f l u i d MSBR.

used t o t r a n s f e r t h e r a r e - e a r t h f i s s i o n p r o d u c t s f r o m t h e r e a c t o r f u e l

s a l t t o an a c c e p t o r s a l t such as L i C 1 . Both t h o r i u m and rare e a r t h s t r a n s f e r t o t h e bismuth; however, because of f a v o r a b l e d i s t r i b u t i o n c o e f f i c i e n t s , o n l y a s m a l l f r a c t i o n of t h e thorium t r a n s f e r s w i t h t h e r a r e e a r t h s from t h e bismuth t o t h e LiCI.

The e f f e c t i v e t h o r i m a r e - e a r t h s e p a r a t i o n f a c t o r s f o r r a r e

e a r t h s f o r which d a t a e x i s t ( i . e . , Nd, L a , and Eu) r a n g e from about 1 0

t o about 10

The f i n a l s t e p of t h e p r o c e s s i s removal of t h e r a r e

e a r t h s from t h e L i C l by e x t r a c t i o n w i t h bismuth c o n t a i n i n g 0.05 t o 0.5

mole f r a c t i o n l i t h i u m . cell.

The new p r o c e s s does n o t r e q u i r e a n e l e c t r o l y t i c

T h i s i s an important advantage o v e r t h e e a r l i e r r e d u c t i v e e x t r a c t i o n

p r o c e s s , which a l s o had t h e d i s a d v a n t a g e of r a r e - e a r t h - t h o r i u m s e p a r a t i o n f a c t o r s near u n i t y . PROTACTINIUM ISOLP~TION USING FLUORINATION--REDUCTIVE EXTRACTION W e have r e c e n t l y developed a new p r o c e s s f o r removing r a r e e a r t h s

from a s i n g l e - f l u i d . MSBR.

T h i s p r o c e s s does n o t r e q u i r e an e l e c t r o l y t i c

cell.,which h a s l e d us t o c o n s i d e r p r o t a c t i n i u m i s o l a t i o n methods t h a t do n o t r e q u i r e e l e c t r o l y z e r s .

One such method i s f l u o r i n a t i o n - - r e d u c -

t i v e e x t r a c t i o n , i n which most of t h e uranium would b e removed pri-or

t o i s o l a t i o n o f t h e p r o t a c t i n i u m by r e d u c t i v e e x t r a c t i o n .

C a l c u l a t e d r e s u l t s i n d i c a t e d t h a t an a t t r a c t i v e p r o c e s s i n g system based on f l u o r i n a t i o n - - r e d u c t i v e

e x t r a c t i o n c a n b e d e v i s e d and t h a t t h i s

system w i l l b e q u i t e s t a b l e w i t h r e s p e c t t o v a r i a t i o n s as l a r g e as 20%

f o r most of t h e important o p e r a t i n g parameters such as flow r a t e s , r e d u c t a n t c o n c e n t r a t i o n s , and number o f e x t r a c t i o n s t a g e s .

AXIAL DISPERSION IN OPEN BUBBLE COLUMNS A x i a l d i s p e r s i o n c o e f f i c i e n t measurements and gas holdup measurements were c a r r i e d o u t i n a 2-in.-ID

open column.

Aqueous s o l u t i o n s

of g l y c e r o l and 2-butanol were used i n o r d e r t o determine t h e e f f e c t of l i q u i d - p h a s e v i s c o s i t y and s u r f a c e t e n s i o n on a x i a l d i s p e r s i o n .

At; low gas flow r a t e s , i n c r e a s i n g t h e Iiquid-phase v i s c o s i t y from 1 CP

t o 15 CP r e s u l t e d i n a 30% d e c r e a s e i n t h e d i s p e r s i o n c o e f f i c i e n t .

f i c i e n t was n o t e d ; however, o n l y a l i m i t e d r a n g e of gas flow r a t e s

bras

h i g h e r gas flow r a t e s , l i t t l e e f f e c t of v i s c o s i t y on d i s p e r s i o n coefexamined. SEMICONTINUOUS REDUCTIVE EXTRPlCTION EXPERIMENTS IN A MILD-STEEL FACILITY Hydrodynamic experiments u s i n g t h e Oe82-in.-diam column packed w i t h s o l i d c y l i n d e r s o f molybdenum were conti-nued.

Only l i m i t e d u s e f u l f l o o d i n g

d a t a were o b t a i n e d because o f d e p o s i t i o n of i r o n i n t h e column as well as

i n t h e bismuth e x i t l i n e from t h e column and t h e salt f e e d l i n e t o t h e c o l -

imn.

The d a t a o b t a i n e d are i n g e n e r a l agreement w i t h p r e d i c t i o n s based on

d a t a from a mercury-water

system.

The col.urnn and t h e a f f e c t e d l i n e s were r e p l a c e d .

The new column i s

shnilar t o t h e o r i g i n a l column e x c e p t t h a t it i s pwked w i t h

molybdenum Kaschig r i n g s .

L/4 -in.4 i . m

SIMTJLATION 08â&#x20AC;&#x2122; TIE FLOW CONTROL SYSTEMS

FOR THE REDUCTIVE EXTRACTION FACILITY

A s t u d y of t h e s a l t and bismuth flow c o n t r o l systems f o r the

Reductive KxtracLion F a c i l i t y w a s made i n o r d e r t o determine t h e b e s t niode of o p e r a t i o n of t h e e x i s t i n g equipment, t o e v a l u a t e p o s s i b l e

vii equi-pment changes, m d t o v e r i f y t h e v a l i d i t y of f l o o d i n g d.ata o b t a i n e d t o date.

One analog and t h r e e d i g T t a l s i m u l a t i o n s w e r e c a r r i e d ou-t.

Each s i m u l a t i o n r e p r e s e n t e d a d i f f e r e n t manner o f c o n t r o l l i n g flow through the column and allowed s e l e c t i o n o f optimum v a l u e s f o r system parameters

All o f t h e systems were found t o be s t a b l e and t o perform s a t i s f a c t o r i l y ; t h u s we b e l i e - v e t h a t t h e a c t u a l system w i l l f u n c t i o n p r o p e r l y . CALIBRFI'TION OF AN ORIFICE--HEAD POT FLOWMETER WITH MOLTEN SALT AND BISMIJTH

A d d i t i o n a l o r i f i c e c a l i b r a t i o n d a t a , b o t h s t e a d y - s t a t e and t r a n s i e n t , were o b t a i n e d .

S i n c e t h e s e d a t a s u g g e s t t h a t t h e o r i f i c e d r a i n chamber

may have been f l o o d e d a t t i m e s , p r o v i s i o n s were made f o r p r e s s u r i z i n g t h e gas volume above t h e f l u i d i n t h e o r i f i c e - - h e a d i n f u t u r e experiments,

p o t and d i s c h a r g e chamber

T h i s w i l l e n s u r e t h a t t h e o r i f i c e d r a i n chamber

does n o t f i l l w i t h l i q u i d . ELECTROLYTIC CELL DEVELOPMENT:

STATIC-CELL EXPERIMEJE'S

Two experiments r e l a t e d t o c e l l development were made i n a 4-in.-diam

quartz c e l l .

I n t h e f i r s t , c u r s e n t w a s passed between two molybdenum

e l e c t r o d e s t o d e t e r m i n e whether a d a r k m a t e r i a l , observed i n t h e s a l t i n p r e v i o u s t e s t s , would b e formed.

Although t h e p r e s e n c e of a d a r k material

w a s n o t e d , w e were not a b l e t o i d e n t i f y t h e mechanism f o r i t s f o r m a t i o n . I n t h e second experiment, we t e s t e d a porous carbon anode having a

much h i g h e r gas p e r m e a b i l i t y t h a n t h a t of a g r a p h i t e anode which had p r e v i o u s l y been observed t o p o l a r i z e , d e n s i t i e s were observed.

A s i n t h e e a r l i e r t e s t , low c u r r e n t

viii

ELECTXOLYTIC CELL DEVETJOPMENT : FORMLlTlON OF ~'KO%F'I\T FILMS WITH AQUHOUS ELECTTIOTJYTES

Formation o f f r o z e n s a l t f i l m s on s t r u c t u r a l . s u r f a c e s exposed t o t h e iiiolten-sa1.t e l e c t r o l y t e i n e l e c t r o l y t i c eel-1.s i s b e i n g c o n s i d e r e d as a means f o r p r o t e c t i n g t h e s e s u r f a c e s from corrosi.on by BiF c e l l anode.

produced al; the

A s t u d y of f r o z e n f i l m formation under c o n d i t i o n s s i - m i l a r t o

t h o s e expected i n a c e l l i s i n p r o g r e s s .

P a r t of t h e work wi.1.l b e c a r r i e d

o u t u s i n g an aqueous e l e c t r o l y t e i n ord-er t o avoid problems a s s o c i a t e d wi.th molten salt--bismut,'n

systems.

Equipment has ' o e m i n s t a 1 l . d f o r s t u d y i n g

t h e formation o f i c e C i l m s on s u r f a c e s of a simulated e l e c t r o l y t i c c e l l - t h a t u s e s an aqueous s o l u t i o n , r a t h e r t h a n molten s a l t , f o r t h e e l e c t r o l y t e . A l t e r n a t i n g c u r r e n t wi1.l b e used t o minimize t h e e f f e c t s of e l e c t r o d e r e a c t i o n s and mass t r a n s f e r . DEVELOPMENT OF A BISMlJTH-MOLTEN-SALT INTERFACE DETECT013 An i n t e r f a c e d e t e c t o r based on t h e p r i n c i p l e of eddy c u r r e n t genera t i o n i n l i q u i d metals i s b e i n g developed.

It i s d e s i r e d t,hat a , l l s u r f a c e s

i n c o n t a c t w i t h bismuth be made of a r e f r a c t o r y m e t a l such as molybdenum, which has a r e l a t i v e l y low e l e c t , s i c a l p e r m e a b i l i t y . I n i t i a l t e s t i n g of t h e e l e c t r o n i c c i r c u i t p r i o r t o i n s t a l l a t i o n e s t a b l i s h e d t h e need f o r s e v e r a l m o d i f i c a t i o n s .

P r e l i m i n a r y t e s t s of

t h e system a t t e m p e r a t u r e s above room t e m p e r a t w e

a r e i n progress.

CONTINUOUS SALT PURIFlCATlON A f a c i l i t y has been designed f o r t h e development of continuous

methods f o r removing contaminants from molten s a l t s .

s i s t s of a l - l / b - i n . - d i m ,

Bl-in.-long

The system con-

column packed w i t h l / b - i n .

Raschig r i n g s , f e e d and r e c e i v e r t a n k s , a s a l t f i l t e r , a flowing stream s a l t sampler, and t h e n e c e s s a r y flow, t e m p e r a t u r e ,

and p r e s s u r e i n s t r u -

mentation,

I n - l i n e i n s t r u m e n t s a r e provided f o r c o n t i n u o u s l y measuring

t h e water and EIF c o n t e n t s of t h e column e x i t g a s stream.

Systems have

a l s o been designed t o p r o v i d e p u r i f i e d hydrogen, a r g o n , and HF g a s . PdSRE DISTILLATION EXPERIMENT

Analyses have been o b t a i n e d f o r L i , B e , Z r , 9 5 Z r 7 144C!e,

155Eu, ”Y,

90Sr, 89Sr, and 137Cs i n t h e 11 condensate samples t a k e n

d u r i n g t h e MSRE D i s t i l l a t i o n Experiment. ities

Effective relative volatil-

f o r each o f t h e s e materials were tal-culated w i t h r e s p e c t t o L i F

d u r i n g the c o u r s e o f t h e experiment.

The c a l c u l a t e d v a l u e s f o r Be, Z r ,

and 9 5 Z r are i n agreement w i t h p r e v i o u s l y r e p o r t e d v a l u e s ; however

v a l u e s c a l c u l a t e d €or t h e r a r e e a r t h s a r e s i g n i f i c a n t l y h i g h e r t h a n v a l u e s measured i n an e q u i l i b r i u m s t i l l . RECOVERY OF

7Li FROM “Lj--BISI’.IIJTR--RARE-EAETH

SOLUTIONS BY DISTILLATION

Removal o f d i v a l e n t l a n t h a n i d e s from t h e L i C l stream i n t h e metalt r a n s f e r p r o c e s s produces a bismuth s t r e a m t h a t c o n t a i n s l a n t h a n i d e s and has a h i g h concentrati.on o f 7 L i ( 5 to 50 a t . % ) .

Because 7 L j i-s

e x p e n s i v e , i t s r e c o v e r y may be economical.

The l o w vapor p r e s s u r e s of t h e l a n t h a n i d e metals r e l a t i v e t o l i t h i u m and bismuth s u g g e s t t h a t d i s t i l l a t i o n might be used e f f e c t i v e l y to r e c o v e r

b o t h t h e l i t h i u m and bismuth.

However, l i t h i u m and bimsuth form a n i i i t e r -

m e t a l l i c compound ( L i - B i ) having a high m e l t i n g p o i n t (lL)-+5;°C) , which may

l i m i t t h e f r a c t i o n of t h e l i t h i u m t h a t c o u l d b e r e c o v e r e d a t s t i l l - p o l t e m p e r a t u r e s o f 800 t o 900°C.

The f r a c t i o n a l r e c o v e r y of Lithium w a s

c a l c u l a t e d f o r a r a n g e of c o n d i t i o n s t h a t vould a l l o w r e a s o n a b l y h i g h recovery of t h e lithium.

PREVENTION OF AXIAL DISPERSION I N PACKED COLUMNS Devices t h a t w i l l reduce a x i a l d i s p e r s i o n i n packed columns Lo acceptable l e v e l s a r e being evaluated.

Two d i s p e r s i o n p r e v e n t e r s irere

t e s t e d d u r i n g t h e c o u n t e r c u r r e n t flow o f mercury and water i n a. 2-in.d i m colwnn packed w i t h 3/8-in.

Xaschig r i n g s .

The p r e v e n t e r s c o n s i s t

o f (1)a seal. formed by a r e g i o n i n which t h e metal. phase a c c i u m l a t e s

and p r e v e n t s flow o f t h e less-dense phase ( s a l t o r w a t e r ) , and ( 2 ) r e s t r i c t i o n s through which t h e s a l t flows a t an i n c r e a s e d v e l o c i t y .

The f r a c t i o n of t h e l e s s - d e n s e phase t h a t i s r e c y c l e d through a d - i s p e r s i o n p r e v e n t e r depends mainly on ,thewater flow r a t e pe-e. r e s t r t c -

t i o n and t h e diameter of t h e r e s t r i c t i o n .

It a p p e a r s that, d e v i c e s o f

t h i s t y p e w i l l reduce a x i a l d i s p e r s i o n t o d e s i r e d l e v e l s ; however, t h e d e v i c e s t e s t e d t o d a t e have reduced the column throughput a t flooding. HYDROUYNAMICS OF PACKED COLWIJY OPERnTION WITH BIGR-DENSITY FLUIJIS Measurements were made of p r e s s u r e d r o p , holdup, and f l o o d i n g d u r i n g t h e c o u n t e r c u r r e n t flow of mercury and water i n columns packed w i t h

i n . s o l i d c y l i n d e r s , 3/8-in.

Raschig r i n g s , and 1 / 2 - i n .

114-

Xaschig r i n g s .

â&#x20AC;&#x2DC;The d a t a on holdup and f l o o d i n g can be c o r r e l a t e d i n terms of a c o n s t a n t s u p e r f i c i a l s l i p v e l o c i t y , which i s a f u n c t i o n o f packing s i z e o n l y .

simple r e l s t i o n has not been found for c o r r e l a t i n g t h e p r e s s u r e drop

data.

An e x p r e s s i o n based on t h e mercury-water d a t a i s g i v e n f o r pre-

d i c t i n g f l o o d i n g and dispersed-phase holdup i n packed columns through which s a l t and bismuth a r e i n c o u n t e r c i r r r e n t flow.

1 1. II!JTRODLJCTION

A molten-salt breeder reactor (MSBR) will be fueled with a molten

fluoride mixture that will circulate through the blanket and core regions

of the reactor and through the primary heat exchangers. We are developing

processing methods for use in a close-coupled facility for removing fission

products, corrosion products, and fissile materials from the molten fluoride

mixt w e

Several operations associated with MSBR processing are under study.

The remaining parts of this report describe:

(1)a newly devised process

(called the metal-transfer process) for removing rare earths from an MSBX,

(2) 2 protactinium isolation process based on fluorination for uranium

removal, followed by reductive extraction, ( 3 ) measurements of axial dis-

persion coefficients in open bubble columns, ( h ) experiments carried out

in a mild-steel reductive extraction facility to study the hydrodynamics

of packed column operation during countercurrent flow oâ&#x201A;Ź molten salt and

bismuth, (5) simulation of the flow control. systems for the reductive

extraction facility, ( 6 ) calibration of an orifice--head pot flowmeter

with molten salt and bismuth, ( 7 ) experiments related to the development or" electrolytic cells f o r use with molten salt and bismuth, (8) design

and installation of a -facility for studying the formation of frozen films in electrolytic cells, using aqueous solutions to simulate molten salt,

( 9 ) development of an induction-type bismuth-salt interface detector,

(LO) design and insta1:lation of a facility for developing continuous

methods for the purification of molten salt, (11)calculation o f

effective relative volatilities for various materials present in the

MSRE Distillation Experiment, (12) calculations concerning the recovery

of 7Li from 7Li--Bi--rare-earth solutjons by low-pressure di stillation,

and (13) measurement of axial dispersion coefficients in packed columns

in which immiscible fluids having large density differences are in countcr-

current flow, and (14) experiments on the hydrodynamics of packed column

operation with liquids having high densities and a large density difference. This wark was carried out in the Chemical Technology Division during the

period October-December 1969.

RmE-E4RTI-I REMOVAL U S I N G THJ3 METAL-TRANSFER PROCESS

L. E . McNeese We have d e v i s e d a new p r o c e s s , c a l l e d t h e m e t a l - t r a n s f e r p r o c e s s ,

f o r removing r a r e - e a r t h f i s s i o n p r o d u c t s from t h e f u e l s a l t of a s i n g l e f l u i d MSBK.

In t h i s p r o c e s s , bismuth c o n t a i n i n g thorium and l i t h i u m i s

uscd t o t r a n s f e r t h e r a r e - e a r t h f i s s i o n p r o d u c t s from t h e r e a c t o r f u e l s a l i t o an a c c e p t o r s a l t such as L i C l .

Both thorium and r a r e e a r t h s t r a n s f e r t o t h e bismuth; however, be-

cause o f f a v o r a b l e d i s t x - i b u t i o n c o e f f i c i e n t s , o n l y a s m a l l f r a c t i o n of t h e thorium t r a n s f e r s w i t h t h e r a r e eizrths from t h e bismuth t o t h e L i C 1 . The e f f e c t i i - v e t h o r i u m - r a r e - e a r t h

separatlon factors for r a r e earths for

which d a t a e x i s t ( i . e . , Nd, L a , and Eu) range from about 10 t o about 1 0

'The f i n a l s t e p o f the p r o c e s s i s removal o f t h e r a r e e a r t h s from t h e LiCl

by e x t r a c t i o n w i t h bismuth c o n t a i n i n g 0.05 t o 0.50 mole f r a c t i o n I.ithium, The new p r o c e s s does n o t r e q u i r e an e l e c t r o l y t i c cell..

T h i s i s an impor-

t a n t advantage over t h e e a r l i e r r e d u c t i v e e x t r a c t i o n p r o c e s s , which al.so had t h e d i s a d v a n t a g e of rare-earth--thorium 2.1

separation factors near unity.

E q u i l i b r i u m Data arrd C o n c e n t r a t i o n s

F e r r i s and Smith

have measured t h e d i s t r i b u t i o n of T1h and t h e r a r e

e a r t h s L a , Nd, and Eu between L i C l and blsmuth c o n t a i n i n g a r e d u c t a n t and have summarized t h e i r d a t a as f o l l o w s :

3 where

D = d i s t r i b u t i o n r a t i o for material A , A x*(si)/xA(Licl)~ = mole f r a c t i o n of A i n B i y 'A(Si) I

= mole fraction of A i n L i C L , 'Ii(Lic1) c1 = lithium concentration i n B i , at. Li

The data for a l l materials except europium were o b t a i n e d a t 640OC; t h e europium data were o b t a i n e d a t

630째C.

Data for t h e d i s t r i b u t i o n o f t h e

makerials b e i n g c o n s i d e r e d between 72-16-12 mole

% LiF-BeF2-ThF4

and

bismuth coiitrzining a r e d u c t a n t have been summarized by F e r r i s as:

log 1) = n l o g DLi A

l o g KA,

where

DA = d i s t r i b u t i o n r a t i o o f material A , n = v a l e n e e of A i n s a l t , I

log KA = m o d i f i e d e q u i l i b r i u m c o n s t a n t . The v a r i a t i o n of l o g K

A w i t h temperature is:

log

r(La

= -2.005

+ 7628/11,

where T = t e m p e r a t u r e , OK, and T h , La, and Eu have v a l e n c e s of

2 i n t h e salt respectively,

3, and

For Nd, t h e measured value of t h e Md-Th

s e p a r a t i o n f a c t o r ( 3 . 0 ) was t a k e n a t Th s a t u r a t i o n a t 600째C, and t h e

same t e m p e r a t u r e dependence w a s assumed f o r l o g

The d e r i v e d e x p r e s s i o n i s , t h e n : 1

Log R Nd

-1.942

-t-

7628/T,

and N d i s assumed t o b e t r i v a l e n t i n t h e s a l t .

as t h a t f o r log K, La .

h Using t h e s e d a t a , t h e c a l c u l a t e d e q u i l i b r i u m c o n c e n t r a t i o n s i n Bi

and L i C l a t

640"~are

as shown i n Table 1, where t h e r a r e - e a r t h con-

c e n t r a t i o n s in t h e f u e l s a l t a r e t h o s e r e s u l t i n g from a 50-day removal

t i m e f o r t h e rare e a r t h s .

The r e d u c t a n t c o n c e n t r a t i o n i n t h e B i w a s

chosen such t h a t t h e T h c o n c e n t r a t i o n w a s approximately 95% of t h e Th solubility i n B i at

6hoOc.

No c o r r e c t i o n was made i n t h e d a t a f o r

europium t o account f o r t h e f a c t t h a t t h e y a r e b e i n g used a t 640째C ( a l t h o u g h t h e y were o b t a i n e d a t 6 3 0 " ~ ) . A l l t h e c o n c e n t r a t i o n s are

g i v e n i n mole f r a c t i o n s ,

Table 1. E q u i l i b r i u m C o n c e n t r a t i o n s i n Fuel S a l t , Bismuth, and Li.CI. a t 61-cO"C Fuel S a l t = 0.72

JT' iF

XhF* =

%hF4 'LaF

'NdF %uF

Bismuth

L' i = 0.00201

0.16

yrh =

= 0.12

-6

10.8 x 10

26.2 x 1 0

-6

3 = 0.287 x 2

LiCl

'IJa

'Nd

0.0025

-6

= 0.524 x 10 =

1.47 x IO-6

= 0.664 x

= 0.331 x 1 0-7

'ThC14

'Lac]. 'NdC I.

3 3

'EUC 1

= 0.607 x lom6

-6

1.02 x 10

8 . 2 2 x io

-6

T'he d a t a i n t h e t a b l e show t h a t t h e rare e a r t h s a r e p r e s e n t i n t h e LI.Cl

a t low c o n c e n t r a t i o n s and a r e a s s o c i a t e d w i t h o n l y a s m a l l amount of thorium.

C l e a r l y , i f a p r a c t i c a l means i s a v a i l a b l e for removing t h e

r a r e e a r t h s and thorium :From t h e L i C l i n t h e r e l - a t i v e c o n c e n t r a t i o n r a t i o s shown, one w i l l have achieved t h e d e s i r e d g o a l of r e m w i n g t h e r a r e e a r t h s w i t h an a c c e p t a b l e thorium d i s c a r d r a t e .

5 2-2 Removal of Rare E a r t h s and Thorium from L i C l The minimum r a t e a t which t h e L i C l s o l u t i o n must b e processed f o r removal of t h e r a r e e a r t h s i s g i v e n by t h e r a t i o of t h e p r o d u c t i o n r a t e of a g i v e n r a r e e a r t h t o i t s e q u i l i b r i u m c o n c e n t r a t i o n i n t h e L i C 1 .

These data, which are shown below, i n d i c a t e t h a t t h e minimum process-

6 g-moles

i n g r a t e , as s e t by Nd, i s 1 . 2 9 x 1 0

i s e q u i v a l e n t t o 1320 f t

o f L i C l p e r day.

3 o f L i C l p e r day, which a p p e a r s t o be a

This

h i g h e r p r o c e s s i n g r a t e t h a n would be p r a c t i c a l f o r low-pressure d i s -

ti l l a t i o n . Rare Ealpth

Prod-uct i o n

Rate

(moles/day)

Concentrat i o n in LiCl (mole f r a c t i o n )

0,607 x low6

Minimum Processing R a te (moles/day)

0.889 x 106

0.54

1.31

1.02 x

1.29 x io

0 0144

8.22 x

1.75

lo3

F u r t h e r c o n s i d e r a t i o n s u g g e s t s t h a t c o n t a c t of t h e L i C l w i t h a small volume of bismuth c o n t a i n i n g a r e l a t i v e l y h i g h c o n c e n t r a t i o n o f l i t h i u m

( 5 t o 50 a t . % ) would p r o v i d e t h e d e s i r e d removal of t h e rare e a r t h s

from t h e L i C l as w e l l as t h e removal o f t h e thorium a s s o c i a t e d w i t h t h e

rare e a r t h s , 2.3

T h i s i s t h e method s e l e c t e d f o r a d d i t i o n a l e v a l u a t i o n .

Conceptual P r o c e s s Flowsheet and Mathematical A n a l y s i s

The c o n c e p t u a l p r o c e s s f l o w s h e e t c o n s i s t s of t h r e e c o n t a c t o r s through which t h e p r o c e s s f l u i d s a r e c i r c u l a t e d , as shown i n F i g . 1. F u e l s a l t

from t h e Pa i s o l a t i o n system, which i s f r e e o f U and Pa. b u t which c o n t a i n s

t h e rare e a r t h s a t t h e r e a c t o r c o n c e n t r a t i o n , i s c o u n t e r c u r r e n t l y c o n t a c t e d

w i t h B i c o n t a i n i n g approximately 0.002 mole f r a c t i o n L i i n c o n t a c t o r 1. The r a r e e a r t h s t r a n s f e r , i n p a r t , t o t h e downflowing m e t a l s t r e a m and

a r e c a r r i e d i n t o c o n t a c t o r 2 by t h e bismuth stream.

I n contactor 2, t h e

bismuth s t r e a m i s c o n t a c t e d c o u n t e r c u r r e n t l y w i t h LiCl, and f r a c t i o n s of

TQ React o r

XM2

FRS,XSI Fuel S a l t From Pa isolation

Li C

Li-Bi

Li-Bi FS M XM6

+ Rare

1- T h

Earths

FM,XMG

r i g . 1. Sletal-'i'ransfer* Process f o r Removinc Rare E a r t i i s from a Sinele-: 1 u i d I\ISBR.

7 the r a r e earths transfer t o t h e LiC1.

The r e s u l t i n g LiCl s t r e a m i s

f i n a l l y c o n t a c t e d w i t h Bi c o n t a i n i n g a h i g h c o n c e n t r a t i o n o f L i ( 0 . 0 5

t o 0.5 mole f r a c t i o n ) i n c o n t a c t o r 3, where most o f t h e r a r e e a r t h s and thorium t r a n s f e r from t h e L i C l t o t h e B i stream.

A small stream of B i

c o n t a i n i n g Li i s f e d t o t h e c i r c u l a t i n g B i stream i n c o n t a c t o r 3, and an equal volume o f bismuth i s withdrawn.

From material b a l a n c e and e q u i l i b r i u m c o n s i d e r a t i o n s , t h e f o l l o w i n g r e l a t i o n s f o r a g i v e n t r a n s f e r r i n g m a t e r i a l can be w r i t t e n f o r t h e t h r e e countercurrent contactors.

The nomenclature o f Fig. 1 i s u s e d .

= KC

xs3 - xs4

ASNSfl - AS

= KS

From m a t e r i a l b a l a n c e c o n s i d e r a t i o n s

xsi - x w XMl

xs3

- xs4

XM6

L/FRS

XM2 = L/FMl = LFCS

XM5 = L/FSM

X M ~=

L/FM,

(3)

8 where X S 1 = c o n c e n t r a t i o n of t r a n s f e r r i n g material i n f u e l salt e n t e r i n g

c o n t a c t o r 1, mole f r a c t i o n , XS2 = c o n c e n t r a t i o n of t r a n s f e r r i n g material. i n f u e l sa1.t l e a v i n g c o n t a c t o r 1, mole f r a c t i o n ,

xT4l

:= c 0 n c e n t r a t i . m of t r a n s f e r y i n g

material 'I.n .Ai l e a v i n g con1;actor

1, mole frac-Lion,

XM2 = c o n c e n t r a t i o n of t r a n s f e r r i n g material i n B i l e a v i n g c o n t a c t o r 2 , mole f r a c t i o n ,

XS3 = c o n c z n . t r a t i o a o f t r a n s f e r r i n g m a t e r i a l i n LiCl l e a v i n g c o n t a c t o r 2 , mole f r a c t t o n ,

X S ~= c o n c e n t r a t i o n of t r a n s f e r r i n g material i n L i C l e n t e r i n g c o n t a c t o r 2 , mole f r a c t i o n ,

XM5

c o n c e n t r a t i o n of t r a n s f e r r i n g material i n Bi e n t e r i n g c o n t a c t o r

3, mole f r a c t i o n ,

XM6 =: e o n c e n t r a t i o n

of t r a n s f e r r i n g m a t e r i a l in

3, mole f r a c t i o n ,

Bi. l e a v i n g c o n t a c t o r

DF = d - i s t r i b u t i o n r a t i o between f u e l s a l t and B i i n c o n t a c t o r 1, DC = d i s t r i b u t i o n r a t i o between L i C l and B i i n c o n t a c t o r 2 , DS = d i s t r . i . b u t i o n r a t i o between L i C l and B i i n c o n t a c t o r 3, A =

FMl.

FMI

AC =

DE'

FRS

FCS

FRS = f i e 1 s a l t flow r a t e , moles/unit t i m e ,

FM1 = metal flow r a t e in c o n t a c t o m 1 and 2 , moles/u.nit t i m e ,

FCS = L i C l s o l u t i o n flow r a t e i n c o n t a c t o r s 2 a.nd 3 , m o l e s / u n i - t t i m e , FM = m e t a l a d d i t i o n and withdrawal r a t e , moles/uni't t i m e , = nunher of e q u i l i b r i u m s t a g e s i.n c o n t a c t o r I ,

U N_ = number of equi.li.briurn s t a g e s i n c o n t a c t o r 2 , J_I

NS = number o f e q u i l i b r i u m s t a g e s i n c o n t a c t o r 3 ,

9 KF = c o n s t a n t , d e f i n e d above,

KC = c o n s t a n t , d e f i n e d above, KS = c o n s t a n t , d e f i n e d above,

L = p r o d u c t i o n r a t e o r l o s s r a t e o f t r a n s f e r r i n g material.

The d i s t r i b u t i o n r a t i o s a r e assumed t o be c o n s t a n t s i n c e t h e r e w i l l be

a very s m a l l change i n r e d u c t a n t c o n c e n t r a t i o n in t h e c o n t a c t o r s ; hence

t h e A ' s and K's d.efined above a r e c o n s t a n t .

The e i g h t r e l a t i o n s l i s t e d above d e f i n e t h e s t a t e o f t h e system

and can be s o l v e d simultaneou.sly f o r t h e removal e f f i c i e n c y f o r a g i v e n m a t m i a l i n e o n t a c t o r 1 as:

AC 1 AC 1 (71 -1) a +(- 1) + KF AF LC *F KS AF%

-1= - 1

where

4 ) ,

(9)

E = f r a c t i o n o f rcaterial removed from f u e l s a l t i n c o n t a c t o r 1.

The removal. t i m e f o r a g i v e n t r a n s f e r r i n g m a t e r i a l i s , t h e n :

Where T

= removal times, d a y s ,

V /FRS = p r o c e s s i n g c y c l e t i m e , d a y s .

'2-4

C a l c u l a t e d Rare-Earth Removal Times

There a p p e a r s t o be g r e a t l a t i t u d e i n choosing o p e r a t i n g c o n d i t i o n s t h a t w i l l y i e l d a d e s i r e d r a r e - e a r t h removal t i m e .

Conditions t h a t g i v e

r a r e - e a r t h removal times e q u a l to, o r somevhat s h o r t e r t h a n , removal t i m e s p r e s e n t l y assumed i n r e a c t o r e v a l u a t i o n c a l c u l a t i o n s w i l l be g i v e n f i r s t .

Those c a l c u l a t i o n s assume a 50-day removal time for a11 r a r e e a r t h s except europium which i s removed on a 225-day c y c l e . Tile table below shows t h e removal t i m e s ( i n days) â&#x201A;Źor t h e f o l l o w i n g c o n d i t i o n s : FRS = 2.94 gpin

10 (3-day p r o c e s s i n g c y c l e f o r r e a c t o r ) ; FM1 = FSM = 8.35 gpm (Bi r a t e s i n c o n t a c t o r s ) ; FCS = 11.2 gpm ( L i C 1 f l o w r a t e ) ; FM = 22.7 I _ i t e r s / d a y ( L l i f e e d and withdrawal r a t e ) ; L i e o n c e n t r a t i o n i n S i i n c o n t a c t o r s 1 and 2 = 0.00201..mole f r a c t i o n ; Li c o n c e n t r a t i o n i n Bi i n c o n t a c t o r 3 = 0.05

mole f r a c t i o n ; and number o f s t a g e s i n c o n t a c t o r 3 = 1.

Rare Earth

No. of E q u i l i b r i i m Sta.ges 1. 2 3

$2 * 1.

58.0

222.4

382 42.7

34.0

C o n t a c t o r s l and 2

32.1

36.5

38.4

219.4.

j.n

219.4

31.,0

35.4

30.2

34.8

21.9.1~ 219.1~ 219.4

It is a p p a r e n t t h a t , w i t h two o r t h r e e s t a g e s i n c o n t a c t o r s 1 and 2 and w i t h volume-Lric flow r a t i o s near u n i t y , one can o'otain s a t i s f a c t o r y

removal t i m e s w i t h r e l a t i v e l y s m a l l p r o c e s s i n g streams, U U ~ S were

6 in.

If packed c o l -

used as t h e c o n t a c t o r s , t h e di.ameters would be approximately

S i n c e t h e number of s t a g e s needed i s low, t h e u s e of m i x e r - s e t t l e r s

similar t o t h o s e b e i n g used a t Argonne N a t i o n a l Laboratory should n o t be d i s m i s s e d , p a r t i c u l a r l y f o r experiments aimed a t demonstrating t h e p r o c e s s concept. The r a t e a t which 7Li i s removed from t h e system i n t h e withdrawal which thorium i.s removed. is

stream i s 52.4 g-moles/day.

The r a t e

l e s s t h a n 0 069 g-mole/day.

If t h e B i withdrawal stream were hydro-

3.t

f 1uori.nat ed o r h y d r o c h l o r i n a t e d i n t h e p r e s e n c e of a s u i t a b l e waste s a l t

i n o r d e r t o r e c o v e r o n l y t h e Bi, t h e c o s t due t o loss of 7 L i would amount

t o 0.0018 m l l / k W h r .

It i s a p p a r e n t t h a t one can o b t a i n removal times much s h o r t e r t h a n t h o s e d i s c u s s e d i n t h e p r e v i o u s s e c t i o n by i n c r e a s i n g t h e bismuth and L i C l flow r a t e s and hence t h e s i z e o f t h e processing p l a n t .

-the r e a c t o r p r o c e s s i n g c y c l e time i s 3 days (2.94 gpm).

I n each c a s e ,

The removal

times r e s u l t i n g from i n c r e a s i n g t h e bismuth and L i C l flow r a t e s t o t e n

tirnes t h e i r p r e v i o u s v a l u e s are g i v e n i n 'Tab12 2 f o r t h e f o l l o w i n g conditions :

11 FRS =

FMl

2.94 gpm (3-day c y c l e ) , FSM = 83.5 gpm ( B i f l o w r a t e i n c o n t a c t o r s ) ,

FCS = 112 gpm ( L i C 1 flow r a t e ) , FTyl =

16 f t '3/day (Bi-Li f e e d and withdrawal r a t e ) ,

L i c o n c e n t r a t i o n i n c o n t a c t o r s 1 and 2 = 0.00201 mole f r a c t i o n , number of s t a g e s i n e o n t a c t o r 3 = 1. Ta.ble 2.

V a r i a t i o n of Rare-Earth Removal T i m e ( i n d a y s ) w i t h Lithium C o n c e n t r a t i o n i n C o n t a c t o r 3 and Number of S t a g e s i n C o n t a c t o r s 1 and 2a

Ear e Earth

No. of Stages i n C o n t a c t o r s 1 and 2 2 3 4 5

L i C o n c e n t r a t i o n i n C o n t a c t o r 3 = 0.05 male f r a c t i o n La Nd

7.75 8.36 16.6

5.26 5.85

14.7

4.43

5.05

1-4 L e

4.03 4.67

13.8

3.79

4.46

13.7

3.54 4.34 13.6

L i C o n c e n t r a t i o n i n Contactor 3 = 0.20 mole f r a c t i o n La

7.59

5 .io

Ell

8.71

6.81

8.22

5-71

4.28 4.91 6.23

3.87

4.54 5.98

3.63 4.33

5.86

4.20

5 .'Y9

L i C o n c e n t r a t i o n i n C o n t a c t o r 3 = 0.50 mole f r a c t i o n

7.59

8.27

8.32

5.10 5 -71 6.37

I+. 27

4.91 5.79

3.87 4.53 5.54

3.63

4.33

5.42

3.48

4.20

5.35

The bismuth and L i C l f l o w rates i n each e a s e a r e assumed t o b e t e n t i m e s t h e v a l u e s used t o produce t h e d a t a shown i n t h e t a b l e on p . 1 0 .

Thus, r a r e - e a r t h removal t i m e s of 3.5 t o about 1.5 days c a n b e obt a i n e d , depending on t h e c o n c e n t r a t i o n of l i t h i u m used i n t h e final contactor.

It s h o d d be noted t h a t one cannot a f f o r d t o Lose t h e L i b y

12 a h y d r o f l u o r i n a t i o n o p e r a t i o n as S e f o r e , but would have t o r e c o v e r most A possib1.e r e c o v e r y method c o n s i s t s of d i s t i l l i n g t h e

o f t h e L i and B i .

stream a t t h e r a t e of about

Li-Bi

1.6 i?t3 /day.

The s t i l l would o p e r a t e

st, a t e m p e r a t u r e of about 800Oc and a p r e s s u r e of approximately 0 . 1 mm Hg,

and t h e r a r e e a r t h s would b e removed i.n a s t i l l - b o t * t o m s volzime of about

20 l i t e r s / d a y .

( T h e bismuth c o u l d be r e c o v e r e d from t h t s volume.)

The

thorium would. be discard-ed a t t h e r a t e of about 1.4 g-moles/day.

2.5

E f f e c t o f Xaye-Earth Removal T i m e on Breeding R a t i o

T h e e f f e c t of r a r e - e a r t h removal. t h e on b r e e d i n g r a t i o has been

c a l c u l a t e d by B e l l 2 and i s shown i n Fig. 2.

The cha.nges are gliven w i t h

r e s p e c t t o t h e base c a s e , i n which a removal time of 50 days i s used f o r a l l t h e r a r e e a r t h s except europi.iim. time. )

(Europtim.has a 225-day removal

It s h o u l d be noted t h a t r a r e - e a r t h removal t h e s of 5 d a y s , 3 days ,

or 7 days would r e s u l t i n i n c r e a s e s i n t h e b r e e d i n g r a t i o of 0.0126, 0 , 0 1 4 , and 0.0115 r e s p e c t i v e l y

2.6

Miscellaneous P o i n t s Related t o t h e Metal-Transfer P r o c e s s

T h e f o l l o w i n g o b s e r v a t i o n s r e l a t i v e t o t h e proposed p r o c e s s have

been n o t e d . 1..

According t o experimental d a t a and c a l c u l a t i . o n s made by F e r r i s L i B r would probably b e a t least as s a t i s f a c t o r y as L i C l as t h e a c c e p t o r saLt.

respec-ts

T h i s f i n d i n g may b e important i n two

It o f f e r s a n o t h e r material w i t h which t o work;

perhaps more i m p o r t a n t l y , however, t h e use of L i B r would

not i n t r o d u c e c h l o r i d e i n t o the i-eactor b u t , i n s t e a d , would siaiply i n c r e a s e t h e c o n c e n t r a t i o n o f bromide a.l.:ready i n t h e system.

'].'hefeed s t r e a m e x i t i n g from {;he Pa i s o l a t i o n system w i l l

have t o b e e s s e n t i a l l y free of U and P a , s i n c e t h e s e mate-

r i a l s would likely nccuniulate i.n .Lhe 9f c i r c u l a t i . n g i-n

0 .Oi 6

ORNL DWG. 69-12121 RI

0.014

:!012

0.0IO

z 0.008

0 W

m Z -

0006 3.004

Cn 0002

a w

u z -

-0.002

pig.

- 9

E f f e c t of R a r e E e r t h Kernoval T i m e on BreediRg R a t i c .

14 c o n t a c t o r s 1 and 2 and t h u s consume t h e L i and Th r e d u c t a n t and p r e v e n t t h e t r a n s f e r of r a r e e a r t h s .

It w i l l probably

be n e c e s s a r y i o t r e a t t h e s a l t stream l e a v i n g t h e Pa i s o l a t i o n system for f u r t h e r removal of U and Pa.

S i n c e v i r t u a l l y a l l of t h e p a r t i t i o n i n g of t h e rare eai-ths from Th i s a. remit o f t h e B i - L i C l

e q u i l i b r i u m , one does

n o t have t o m a i n t a i n t h e p r e s e n t t r e e f l u o r i d e c o n t e n t of

t h e f u e l s a l t and, hence, c o u l d a l t e r t h e r e a c t o r f u e l s a l t composition.

While t h e r e

s no chemical method f o r t r a n s f e r r i n g c h l o r i d e

i o n t o t h e r e a c t o r fuel. s a l t , entrainment of L i C l i n t h e b i s muth l e a v i n g t h e second c o n t a c t o r would t r a n s f e r c h l o r i d e t o the reactor.

Foi-tunately, t h e r e a p p e a r s t o be l e s s l i k e l i -

hood o f t h i s t y p e of entrainrrient t h a n t h e entrainment of t h e bismuth i n t h e s a l t .

It may be n e c e s s a r y t o t r e a t t h e s a l t

r e t u r n i n g t o t h e r e a c t o r by h y d r o f l u o r i n a t i o n o r f l u o r i n a t i o n

for removal of c h l o r i d e .

Another a l t e r n a t i v e w0ul.d be t o pass

t h e bismuth from c o n t a c t o r 2 through a c a p t i v e f l u o r i d e salt

volume ( s u c h a s 72-2.6-12mole

LiF-HeF -ThF ); t h i s would

probably r e s u l t i n removal o f t h e e n t r a i n e d c h l o r i d e salt.

Although t h e i n h e r e n t consumption o f r e d u c t a n t f o r t h i s p r o c e s s

i s q u i t e low (%15 g-moles of l i t h i u m p e r d a y ) , t h e i n t r o d u c t i o n

of o x i d a n t s (or even hydrogen) could i n c r e a s e t h e l i t h i u m consumption s i g n i f i c a n t l y .

The proposed r a r e - e a r t h removal p r o c e s s does not r e q u i r e an e l e c t r o l y t i c c e l l , and t h e o p e r a t i o n of p r o t a c t i n i u m removal systems not r e q u i r i n g a c e l l should be k e p t i n mind as a desired goal.

A n a l t e r n a t i v e t o u s i n g a cell i s f l u o r i n a t i o n

of t h e uranium on a 3-day c y c l e followed by reducLive e x t r a c t i o n processing f o r p r o t a c t i n i u m i s o l a t i o n .

The c o s t of t h e

f l u o r i n e , assuming 100% f l u o r i n e u t i ] - i z a t i o n and a f l u o r i n e

pri-ce of $ 2 / l b , would be 0.02 mill/k!dhr.

Conditions i n t h e c i r c u l a t i n g B i l o o p s a r e always r e d u c i n g

s o t h a t a c o r r o s i o n i n h i b i t o r such as Z r ~roul-dl i k e l y remain i n the B i .

T h i s may a l l o w Croloy t o be used as t h e material

of c o n s t r u c t i o n , a l t h o u g h t h e o p e r a t i n g t e m p e r a t u r e i s s i g n i f i c a n t l y h i g h e r t h a n t h e r a n g e i n which t h e use of Croloy

w i t h zj.rconium i n h i b i t i o n was s u c c e s s f u l .

PROTACTINIUM ISOLATION TJSING FLUORINATION--REDUCTIVE EXTRACTION 1,. E . McNeese

W e have r e c e n t l y developed a new p r o c e s s f o r removing r a r e e a r t h s from a s i n g l e - f l u i d MSBK.

The advantages of t h i s p r o c e s s , which does not

r e q u i r e a n e l e c t r o l y t i c c e l l , have l e d u s t o c o n s i d e r p r o t a c t i n i u m i s o l a t i o n systems t h a t do not r e q u i r e e l e c t r o l y z e r s .

One p r o t a c t i n i u m i s o l a -

t i o n method i n which a n e l e c t r o l y z e r i s not r e q u i r e d i s f l u o r i n a t i o n - reductive extraction.

I n t h i s method, most of t h e uraniuE would b e r e -

moved from t h e f u e l s a l t by f l u o r i n a t i o n p r i o r t o i s o l a t i o n of t h e p r o t a c t i n i u m by r e d u c t i v e e x t r a c t i o n .

3.1

Troposed Flowsheet f o r I s o l a t i n g : P r o t a c t i n i u m by Fluorination--Reductive E x t r a c t i o n

The f l u o r i n a t i o n - - r e d u c t i v e

e x t r a c t i o n system f o r i s o l a t i n g p r o t -

a c t i n i u m i s shown i n i t s s i m p l e s t form i n F i g . 3.

The salt s t r e a n from

t h e r e a c t o r f i r s t p a s s e s t h r o u g h a f l u o r i n a t o r , where most of t h e uranium

i s removed by f l u o r i n a t i o n .

Approximately 90% of t h e s a l t l e a v i n g t h e

f l u o r i n a t o r i s f e d t o a n e x t r a c t i o n column, where it is c o u n t e r c u r r e n t l y c o n t a c t e d w i t h a bismuth stream c o n t a i n i n g l i t h i u m and thorium.

The

uranium i s p r e f e r e n t i a l l y removed from t h e s a l t i n t h e lower e x t r a c t o r , and t h e p r o t a c t i n i u m i s removed b y t h e upper c o n t a c t o r .

A tank through

which t h e bismuth flows i s provided f o r r e t a i n i n g most of t h e p r o t a c t i n i u m i n t h e system.

ORNL- DWG-59-13169

uF6

Li,Th

Sig. 3. Extraction.

Isolation of P r o t a c t i n i u m by - l u o r i n a t i o n - R e d u c t i v e

T h e bismuth stream l e a v i n g t h e lower c o n t a c t o r c o n t a i n s some p r o t a c t i n i u m , as w e l l as t h e uranium t h a t w a s n o t removed i n t h e f l u o r i n a t o r

and t h e uranium t h a t w a s produced by t h e decay o f p r o t a c t i n i u m .

This

s t r e a m i s c o n t a c t e d w i t h a H -1IEâ&#x20AC;&#x2122;mixture Fn t h e presence of approximately 2 lo$ o f t h e s a l t l e a v i n g t h e f l u o r i n a t o r i n o r d e r t o t r a n s f e r t h e uranium

and t h e p r o t a c t i n i i m t o t h e s a l t .

The s a l t stream, c o n t a i n i n g UF4 and

PaF4, i s t h e n r e t u r n e d t o a p o i n t upstream of t h e f l u o r i n a t o r , where most of t h e uranium i s removed.

The p r o t a c t i n i u m p a s s e s through t h e

f l u o r i n a t o r and i s s u b s e q u e n t l y e x t r a c t e d i n t o t h e bismut,li:.

Reductant

(Li and Th) i s added t o t h e B i stream l e a v i n g t h e o x i d i z e r , and t h e

r e s u l t i n g s t r e a m i s r e t u r n e d t o t h e upper c o n t a c t o r .

The s a l t s t r e a m

l e a v i n g t h e upper e o n t a c t o r i s e s s e n t i a l l y f r e e of uranium and p r o t a c t i n i u m and would b e processed f o r remova.1 of r a r e e a r t h s b e f o r e b e i n g returned t o the reactor. 3.2

C a l c u l a t e d System Performance

C a l c u l a t i o n s have shown t h a t t h e system i s q u i t e s t a b l e w i t h r e s p e c t t o v a r i a t i o n s as l a r g e as 20% for most of t h e important p a r a m e t e r s ( i . e . , flow r a t e s , r e d u c t a n t c o n c e n t r a t i o n s , and number o f e x t r a c t i o n s t a g e s ) .

The r e q u i r e d uranium removal e f f i c i e n c y i n t h e f l u o r i n a t o r i s l e s s t h a n

90%. The number o f s t a g e s r e q u i r e d i n t h e e x t r a c t o r s i s r e l a b i v e l y l o w , and t h e m e t a l - t o - s a l t

f l o w r a t i o ( a b o u t 0 . 2 6 ) i s i n a r a n g e where t h e

e f f e c t s o f a x i a l d i s p e r s i o n i n packed column e x t r a c t o r s w i l l be n e g l i gible.

S i n c e t h e p r o t a c t i n i u m removal e f f i c i e n c y i s v e r y h i g h arid t h e

system i s q u i t e s t a b l e , materials such as 231Pa, accumulate w i t h t h e 233Paa

Zr, and Pu should

These materials; can be removed by hydroflu-

o r i n a t i o n o f a small T r a c t i o n of t h e bismuth stream l e a v i n g t h e lower e x t r a c t o r i n t h e p r e s e n c e of s a l t which i s t h e n f l u o r i n a t e d f o r uranium recovery.

S u f f i c i e n t decay t i m e would b e allowed f o r most of t h e 233Pa

t o decay t o 233U, and t h e 233Pa and 233U l o s s e s would b e a c c e p t a b l y l o w .

18 Operating c o n d i t i o n s t h a t w i l l y i e l d a 10-day protactixiium r,amoval t i m e i n c l u d e a f u e l s a l t flow r a t e of 0.88 gpm (10-day p r o c e s s i n g c y c l e ) ,

a bismuth flow r a t e oT 0.23 gpm, two s t a g e s i n -the lower c o n t a c t o r and

s i x t o e i g h t s t a g e s i n the upper c o n t a c t o r , and a decay t a n k vol.ume of 200 t o 300 f t3 The r e q u i r e d q u a n t i t y of r e d u c t a n t i s 340 toj1.30

equiv/day, which will c o s t 0.012 t o 0.015 mill/kWir i f 7 L i i.s purchased.

The remainder of t h i s s e c t i o n i s devoted t o

e f f e c L s of important system p a r a m e t e r s .

d i s c u s s i o n of t h e

Unless o t h e r w i s e s t a t e d , t h e

o p e r a t i n g c o n d i t i o n s i.ncl_u.de an o p e r a t i n g t e m p e r a t u r e of 640째C,

p r o c e s s i n g c y c l e time of 10 d a y s , a. r e d u c t a n t a.ddi.tion r a t e o f 4-29

eqizi.valents/day, a p r o t a c t i n i u m d.ecay t a n k volume of 300 f t 3 , a ruaxinim

thorium c o n c e n t r a t i o n e q u i v a l e n t t o 50% of t h e thorium s o l u b i l i t y a t

64OoC, and a uranium removal e f f i c i e n c y d u r i n g f l . u o r i n a t i o n of 98%. The e f f e c t of t h e number o f e q u i l i b r i u m s t a g e s i n t h e upper ext r a c t o r on p r o t a c t i n i u m removal Lime and uranium i n v e n t o r y i n t h e decay t a n k i s shown i n F i g . c o n t a c t o r ; however contac Lor.

, inore

Less t h a n two s t a g e s a r e r e q u i r e d i n the lower s t a g e s can h e used t o advantage i n -the upper

Approximately- f i v e s t a g e s are adequate ; l i t t l e b e n e f i t i s

o b t a i n e d f r o m u s i n g addi1;ional o n e s . The e f f e c t of t h e f r a c t i o n of urariiuni t h a t i s n o t removed d u r i n g f l u o r i n a t i o n i s shown i n F i g . 5 .

High uranium removal e f f i c i e n c i e s

are not r e q u i r e d s i n c e the r e t e n t i o n of a s niuch as 1 2 % of t,he i r a n i i m

i n t h e s a l t c a u s e s no harmful consequences.

The e f f e c t o f reductant, a d d i t i o n r a t e i s shown i n Fig. 6.

e f f e c t o f d e c r e a s i n g t h e a d d i t i o n r a t e i s seen u n t i l one r e a c h e s a v a l u e o f 390 e q u i v l d n y , where a gradual b u t s i g n i f i c a n t e f f e c t b e g i n s

t o b e observed.

The changes shown a r e approximately t h o s e changes

which r e s u l t from v a r i a t i o n s i n the bismuth f l o w r a t e f o r a. constant;

inl.et reductant Concentration.

Hence, t h e r e i s l i t t l e e f f e c t of

v a r i a t i o n s i n t h e bismuth f l o w r a t e .

TEMPERATURE, 640 *C PROCESSING CYCLE, IO DAYS Li REQUIREMENT, 4 2 9 MOLES L i / D A Y DECAY TANK VOLUME, 300 f t 3 M E T A L TO SALT FLOW RATIO, 0.26

Fig.

NUMBER

OF STAGES

IN UPPER COLUMN

V a r i a t i o r i of Prot;aetinium Removal T i m e and Urtznii-un Inven-Lory in I>ecay Tsnk w i t h Nurnber of Stages in TJpper Cohxnn.

ORNL DWG 69-13179 R l

16 cn

r... k-

z'>

0 a

TEMPERATURE 6 4 6 O C DECAY TANK VOLUME, 300 f t 3 STAGES IN UPPER COLUMN, 6 STAGES IN LOWER COLUMN, 2 METAL TO S A L T FLOW R A T I O , 0 . 2 6 REDUCTANT FEED RATE, 428.6 e q l d a y

0.02

0.04

0.06

0.08

0.10

0.12

0.14

F R.A C I J NOT REMOVED BY FLUORINATION - TIO - N OF -

Fig. 5. Variation of P r o t a c t , i n i u m R m o v a l Time ana Uranium Inveniory in Decay Tank w i t h Fraction of Uranium IJot Removed by Fluorination.

O R N L DWG 69-13178

7 TEMPERATURE 6 4 0 ' C DECAY TANK VOLUME 300 f t 3 STAGES I N UPPER COLUMN I O STAGES I N LOWER COLUMN 2 PROCESSING CYCLE 10 DAYS

300

320

340

360

380

400

REDUCTANT FEED RATE T e q / D A Y )

420

0 440

~~ Time F i g . 6. E f f e c t of Reductant Feed Rate on P r o t a c t i n i . ~Removal and. LJr:mium 1nventor.y i n the Protactinium Decay Tank.

22 The e f f e c t of p r o c e s s i n g c y c l e t i m e on p r o t a c t i n i u m removal!. t i m e and uranium i n v e n t o r y i n t h e decay t a n k i s shown i n F i g .

The removal

time i s e q u a l t o t h e p r o c e s s i n g c y c l e time (100% removal e f f i c i e n c y ) Tor p r o c e s s i n g c y c l e t i m e s g r e a t e r t h a n about 1 0 days. c y c l e t i m e i s d e c r e a s e d below t h i s p o i n t

loses etficiency.

A s t h e processing

however., t h e system slowly

F i g u r e 7 shows t h a t t h e sys-t,em i s r e l a t i v e l y insen-

sit,.ive t o minor v a r i a t i o n s i n t h e s a l t f e e d r a t e . The e f f e c t o f t h e p r o t a c t i n i u m decay t a n k volume i s shown i n F i g .

No change i.s seen as t h e t a n k volume i s d e c r e a s e d from t h e nominal

volume of 300 f t 3 u n t i l a v a l u e o f 280 f t ’3 i s r e a c h e d ; a t t h i s p o i n t , t h e system slowly l o s e s e f f i c i e n c y .

Smaller tank volimes c o u l d be used

without loss o f removal e f f i c i e n c y by i n c r e a s i n g t h e r e d u c t a n t concen-

t r a t i o n i n t h e bismuth f e d t o t h e e x t r a c t o r s .

The e f f e c t s o f o p e r a t i n g t e m p e r a t u r e and r e d u c t a n t a d d i t i o n r a t e on p r o t a c t i n i u m removal time a r e shown i n F i g .

9. The optimum o p e r a t i n g

t e m p e r a t u r e i s about 6~+ooc,and ‘the system i s r e l a t i v e l y i n s e n s i t i v e t o minor temperature v a r i a t i o n s .

The r e d u c t a n - t c o s t s a s s o c i a t e d w i t h t h e

a d d i t i o n r a t e s showri d e c r e a s e i n increments of 0.001 mi.3.l./kWhr from v a l u e o f 0.015 milL/kWhr f o r a n a d d i t i o n r a t e of

4. AXIAL DISPERSION IN OPEN J. S . Watson

429 equiv/day.

BUBBLE COLUMNS

L. E . McNeese

A-xial mixing or d i s p e r s i o n i s l i k e l y t o be important i n continuous f l u o r i n a t o r d e s i g n and perforinance.

Because molten s a l t s a t u i - a t e d wit;h

f l u o r i n e i s c o r r o s i v e , f l u o r i n a t o r s w i l l be s i m p l e , open v e s s e l s that, have a p r o t e c t i v e l a y e r of f r o z e n s a l t c o v e r i n g a l l exposed m e t a l wa1.l~ and s u r f a c e s .

i n the salt.

T h e r i . s i n g gas bubbles may cau.se a p p r e c i a b l e a x i a l mixing

We have p r e v i o u s l y 3 measured a x i a l d i s p e r s i o n c o e f f i c i e n t s

column u s i n g a i r and water t o sirnulate f l u o r i n e and s a l t . 2 Axial. d i s p e r s i o n c o e f f i c i e n t s between 2’5 and 35 cm / s e e were observed f o r i n a 2-in.-diam

gas flow r a t e s between 3 and 30 cm3 / s e c and were independent of t h e l i q u i d

30r ORNL

..........

D W G 69-13176

24 TEMPERATURE

DECAY TANK VOLUME STAGES IN UPPER COLUMN STAGES IN L O W E R COLUMN REDUCTANT FEED RATE

0 '0

64O0 C

300 f t 3 6

2 4 2 0 . 6 sq/do

a >

I w

(1:

a 0

4 6 E! IO PROCESSING C Y C L E T I M E ( d a y s )

Fig. 7. E f f e c t of Processin!; Cyc1.e T i m e on P r o t a c t i - n i u m Removal T ' t m e an83 IJranium I r i v e n t o r y in Decay Ta.nk.

> a

0 IP

E-

1.0 o

a w a:

o"-" x E

T FEED RATE 4 2 8 6 eq/da UPPER COLUMN I O

6 % 0 w c3

z 4 & 8

I-

z Ld > z -

I 3

180

200

220 240 260 280 Pa D E C A Y TANK V O L U M E , f t 3

300

cz o =

320

r i g . 8. Effect of t h e Protactinium Decay Tank Volume on Protactiniim Removal Y'be and Uraniixn Inventory in the Protactinium Decay Tank.

I!:

......

PROCESSING CYCLE, 10 DAYS

..._.

STAGES IN UPPER COLUMN, 10 STAGES IN LOWER COLUMN, 2

I€

DECAY TANK VOLUME, 300FT3

16 v,

-CY

3 0 z W

10 TEMPERATURE ( O C ) Fig. 9.

V a r i a t i o n of Protac-Liriiurn fiernova.l 'Tim(? writh Reductant

Addi.tion Ra-Le a n d O p e r a t i n g Temperature.

26 ( w a t e r ) flow r a t e .

i n t h i s flow r a n g e , termed "bubbly flow," t h e gas

moves up the column i n Liie form of d j - s c r e t e b u b b l e s .

When t h e g a s flow

r a t e i s i n c r e a s e d t o g r e a t e r t h a n 30 c m3/ s e e , "sl.u.gging flow" occurs

and t h e gas bubbles c o a l e s c e and may f i l l t h e e n t i r e c r o s s s e c t i o n of t h e column.

I n t h i s flow r a n g e , t h e d i f f u s i o n coeffl.ci.ent i s more

dependent on gas flow r a - t e ; it i s approximately p r o p o r t i o n a l t o t h e s q u a r e r o o t o f t h e voliimetric g a s flow r a t e . The air-water system d i f f e r s from t h e s a l t - f l . i m r i n e system i n two significant respects:

(1)t h e v i s c o s t t y of s a l t i s 1.5 t o 30 t i m e s h i g h e r

t h a n t h a t o f water, and (2) t h e s u r f a c e t e n s i o n o f water i s about 7 5 dynes/cm as compared w i t h about 200 Clyneslcm for s a l t .

O f course, t h e

d e n s i t y of s a l t i s about t h r e e times t h a t of w a t e r , b u t t h i s d i f f e r e n c e

i s b e l i e v e d t o be of l e s s importance.

The p r e s e n t s t u d y , performed by I+ a group of MIT P r a c t i c e School s t u d e n t s , w a s carried o u t t o i n v e s t i g a t e

t h e e f f e c t s o f v i s c o s i t y and s u r f a c e t e n s i o n on t h e d i s p e r s i o n c o e f f i c i e n t .

4.1

Experimental Technique and Equipment

The e x p e r i m e n t a l t e c h n i q u e and equipment were t h e same a s t h o s e used e a r l i e r . 3

ft.

T'ne column was 2 i n . i n d i a m e t e r and had a l e n g t h of

'The gas i n l e t w a s 0.04 i n . I D .

A 0.5 M Cu(N0 ) I

3 2

tracer was

c o n t i n u o u s l y i n j e c t e d i n t o t h e bottom o f t h e column, and t h e steadys t a t e c o n c e n t r a t i o n o f t r a c e r was meamred. p h o t o m e t r i c a l l y upstream

at several points.

A t each measuring p o i n t , a sanqi1..e o f solution w a s

removed from t h e col.unm, c i i - c u l a t e d through a photocell., and r e t u r n e d t o t h e colwmi a t t h e same e l e v a t i o n .

The e f f e c t s of l i q u i d v i s c o s i t y and s u r f a c e t e n s i o n were s t u d i e d separately.

The v i s c o s i t y of t h e l i q u i d f e d t o t h e colimn w a s increa.sed

t o 1 5 cP by adding glycerol.

The s u r f a c e t e n s i o n of t h e l i q u i d was

va.ried between 37.8 and 67.4 dynes/cm by adding E-butanol. t o w a t e r . (The s u r f a c e t e n s i o n of w a t e r i s

75 c P . )

Addition of t h e g l y c e r o l

r e s u l t e d i n p r o p e r t i e s c l o s e r t o t h e p r o c e s s c o n d i t i o n s ; hoxever, t h e d e c r e a s e i n s u r f a c e t e n s i o n r e s u l t e d i n p r o p e r t i e s f a r t h e r removed from process conditions.

N e v e r t h e l e s s , d a t a were o b t a i n e d on t h e e f f e c t s of

v a r i a t i o n s i n s u r f a c e t e n s i o n and v i s c o s i t y .

4-2

Experimentally Determined D i s p e r s i o n C o e f f i c i e n t s

E x p e r i m e n t a l l y determined v a l u e s f o r t h e d i s p e r s i o n c o e f f i c i e n t a r e swrunarized i n F i g . 1 0 .

A t low gas f l o w rates, t h e d i s p e r s i o n c o e f f i c i e n t s

f o r a g l y c e r o l - w a t e r m i x t u r e w i t h a v i s c o s i t y o f 15 cP ase about 30% belob;

'chose observed f o r water a l o n e .

The t r a n s i t i o n from bubbly t o s l u g g i n g

flow o c c u r s a t a g a s flow r a t e o f about 26 em3 / s e c .

A t higher r a t e s , the

d i s p e r s i o n c o e f f i c i e n t v a l u e s approach t h o s e observed w i t h w a t e r .

Unfor-

t u n a t e l y , t h e d a t a f o r g l y c e r o l i n F i g . 10 do not extend t o h i g h a i r flow

r a t e s ; however, t h e data a t t h e s e r a t e s p r o b a b l y approximate t h o s e obt a i ned w i t h w a t e r .

I n t h e bubbly r e g i o n , t h e gas b u b b l e s were smaller t h a n t h o s e ob-

s e r v e d a t t h e same g a s f l o w r a t e w i t h water, and t h e t e r m i n a l r i s e v e l o c i t i e s were lower.

However, t h e t e r m i n a l v e l o c i t y of "slugs" of

g a s i n t h e h i g h gas flow r a t e r e g i o n became independent of v i s c o s i t y , a l t h o u g h t h e s l u g s were p r o b a b l y l a r g e r t h a n w i t h w a t e r .

This i s

because t h e gas holdup or v o i d f r a c t i o n i n c r e a s e d w i t h i n c r e a s i n g v i s c o s i t y (Fig. 3.1). The a d d i t i o n of ;-butanol

t o water t o d e c r e a s e t h e s u r f a c e t e n s i o n

r e s u l t e d i n a n i n c r e a s e i n d i s p e r s i o n c o e f f i c i e n t , as shown i n F i g . 10. These r e s u l t s , however, are n o t c o n c l u s i v e because of p o s s i b l e concen-

t r a t i o n of t h e E-butanol a t t h e g a s - l i q u i d i n t e r f a c e s .

Butanol

and

o t h e r s u r f a c e - a c t i v e m a t e r i a l s may have c o n c e n t r a t e d a t t h e i n t e r f a c e

so t h a t t h e a c t u a l c o n c e n t r a t i o n s a t t h e i n t e r f a c e (and t h u s t h e s u r f a c e t e n s i o n ) would n o t be known.

The i n t e r f a c e c o u l d be more r i g i d t h a n ,an

air-water i n t e r f a c e , and t h i s e f f e c t a l o n e could i n c r e a s e t h e d i s p e r s i o n

O R N L - DWG-70-11038 R Z

200

-u

100

Butanol-Woter Solutton,

A - Butanol-Water Solution,

Butanol-Water Solution,

37.8 dynes/cm

= 53.2 dynes/cm

u = 67.4 dyneslcrn (single r u n )

Glycerol-Water Solution, y

= 15 c p

E Y

.-* *b

60 50 40

8 1 0

GOS FIOW

. L . 30 40 5060 80 100

200

Rate (cm31sec)

F i g . io. E f f e c t of Liquid Surface Tension and V i s c o s i t y on Dispersi-on in an Open Bubble Column.

ORNL D W G 70-11040RI

2ts 5

0 Butanol-Water S o i u t i o n , a = 37.8 dynes/cm A Butanol-Water Solution, u = 53.2 dyneslcm 0 D i s t i l l e d Water 0 G l y c e r o l - W a f e r Solution. ~ = 1 CP 3

3 8 40 50 60 G o s Flow R a t e (crn3/sec)

80 100

coefficient.

The same problem could have e x i s t e d i n t h e g l y c e r o l -

water experiments; however, t h e g l y c e r o l c o n c e n t r a t i o n w a s s u f f i c i e n t l y high t h a t t h e c o n c e n t r a t i o n of g l y c e r o l a t t h e s u r f a c e i s no-t bel.j.eved. t o have been s e r i o u s .

Although i t i s d e s i r a b l e i n experiments siich as

t h e s e t o use pure components, i t i s f r e q u e n t l y , as i n t h i s c a s e , not practical.

5. SEMICONTINUOUS REDUCTIVE

EX'~'LUCTIONEXPERIMENTS

IN A IllILD-STEEL FACILITY

B. A . Hannaford C . W. Kee L. E. McNeese Hydrodynamic experiments w i t h t h e 0 . 8 2 - i n . 4 i a m 1/4-in.

s o l i d c y l i n d e r s of rnolybdenum were c o n t i n u e d .

column packed with 0nl.y l i m i t e d u s e f u l

f l o o d i n g data w e r e o b t a i n e d because o f d e p o s i t i o n of i r o n i n t h e column as

w e l l as i n t h e bismuth e x t t l i n e from t h e column and t h e s a l t f e e d l i n e t o t h e colimm.

T h e d a t a o b t a i n e d are i n genel-a1 agreement w i t h p r e d i c t i o n s

based on d a t a from a mercury-wat,er

system.

The column al?d t h e a f f e c t e d

7.ines were removed f o r repl.acemftnt.

5.1

Hydrodynamic Run

HR-6

Only Limited u s e f u l f l o o d i n g data were o b t a i n e d i n run m-6 de:;pi.te

good coni;rol o f t h e r a t e s of flow of 'oismuth and s a l t from the r e s p e c t i v e

feed tanks.

Subsequent exaLminat,ion of t r a n s f e r l i n e s a t t a c h e d t o t h e c c l -

umn suggested -thaL t h e unexpectedly h i g h bismuth holdup may have been due t o a d e p o s i t o f i r o n accumulating i n t h e t r a n s f e r I.iiles.

The schematic diagram o f t h e experimental equipment (Fig. 1 2 ) i n -

d i c a t e s the m.etbod by T i h i c h the p r e s s u r e at the base of the col.umn ( a

wensiire of t h e bismuth holdup) w a s deduced.

A s long as s a l t i s e n t e r i n g

t h e column, t h e p r e s s u r e a t t h e b a s e of t h e column i s e q u a l t o t h e sum

of (7.) t h e s t a t i c column of sa7.t between t h e column i n l e t and t h e j a c k l e g

31 O R N L DWG 70-11039 Pressurizing 1 A

D--pl-.s - - _.- -- -

1 ........1........................

A r g o n Bleed

-,,++

JConpot

oit Level 1 l e i - Recorder J

+Argon

Bubbler

S a l t Jackleg

Bismuth Entrainment Detector SG-12

Salt

Feed

/Sa i t B ismc In t erfoc (Constant I

(

\Dendritic Iron Deposits

Fig. 12. Packed Column and :<elated Coriiporiertts Shown i n 'Yrue Elev a t i o n ; Schemat,ic Diagram of Level C o n t r o l S y s t e m f o r Salt J a c k l e g -

32 b u b b l e r , ( 2 ) t h e v a r i a b l e s a l t head i n t h e j a c k l e g , and ( 3 ) t h e v a r i a b l e argon p r e s s u r e above t h e s a l t i n t h e j a c k l e g .

P r e s s u r e drop due

t o s a l t flow i n t h e l i n e connecting t h e j a c k l e g and t h e column i s negligible

Run HR-6 began w i t h a s a l t flow to t h e column of about 75 ml./min;

however, when bismuth f l o w was s t a r t e d , t h e p r e s s u r e a t t h e b a s e of t h e co1i.im.n began t o i n c r e a s e r a p i d l y as r e f l e c t e d by a r a p i d l y i n c r e a s i n g argon p r e s s u r e i n t h e j a c k l e g ,

By s t e p v i s e i n c r e a s e of t h e

l e v e l s e t - p o i n t i n t h e j a c k l e g , it w a s p o s s i b l e t o accommodate t h e i n c r e a s i n g p r e s s u r e d r o p a c r o s s the column. about

1'75 ml/min

A t a bismuth flow r a t e of

and a s a l t flow r a t e of '75 ml/xnin, t h e p r e s s u r e a t

t h e b a s e of t h e column w a s about 250 i n . H 0 and was i n c r e a s i n g slowly. A t t h i s pressure

, the

b i s m u t h - s a l t i n t e r f a c e below t h e colimin would b e

w i t h i n a few i n c h e s of -the bottom o f t h e bismuth d r a i n l o o p ; t h u s t h e bismuth -flow r a t e vas reduced i n o r d e r to p r e v e n t t h e salt-metal i n t e r f a c e from being f o r c e d through t h e d r a i n loop.

D e s p i t e a high bismuth

holdup ( % B O % ) i n f e r r e d from t h e p r e s s u r e a t t h e base of t h e column, no o b s e r v a b l e q u a n t i t y of bismuth w a s c a r r i e d o u t -the t o p of t h e column

w i t h t h e s a l t ; t h a t i s , no v a r i a t i o n s were observed i n t h e s i g n a l from

t h e bismuth entrainment d e t e c t o r (Fig* 1 2 ) t h a t w a s b e i n g o p e r a t e d w i t h

the f r e e z e v a l v e open. 5.2

Hydrodynamic Runs IiR-7 and. HR-8 ; Tests f o r 0bst:ructicJns

Run HR-7 was begun a t t h e lowest p o s s i b l e flow r a t e s (%SO ml/min

f o r each p h a s e ) ; however, flow of s a l t through t h e column was o b t a i n e d o n l y during a b r i e f i.nterva1 d u r i n g v h i c h t h e s a l t j a c k l e g showed a p r e s s u r e e q u i v a l e n t t o a s t a t i c column of bismuth f i l l i n g t h e e x t r a c t i o n column.

Bismuth flowed from t h e column o n l y by way of t h e s a l t

overflow * The p r e s e n c e of s u s p e c t e d p l u g s i n l i n e s a t t a c h e d t o t h e b a s e o f t h e column w a s v e r i f i e d by removing t h e l i n e s and s e c t i o n i n g them. f o r

33 De-

examination a f t e r m e l t i n g o u t t h e bismuth i n an argon a h o s p h e r e .

p o s i t s of i r o n c r y s t a l s , some of which were e x t e n s i v e enough t o con-

s t l t u t e impermeable p l u g s ( F i g . 131, were found i n t h e l o c u t i o n s i n -

d i c a t e d i n Fig. 1 2 .

S a l t and bismuth we1.e d r a i n e d from t h e column i n t o a temporary r e c e i v e r t o permit t e s t s t o determine t h e c o n d i t i o n of t h e molybdenum packing.

Radiographs of t h e column showed r e g i o n s of t r a p p e d bismuth

which might i n d i c a t e a plug.

Measurements showed a presslire d r o p about

2 . 5 times t h a t of a, r e f e r e n c e col-umn packed w i t h p o l y e t h y l e n e cyl.inders;

however, t h i s w a s n o t r e g a r d e d as c o n c l u s i v e evidence o f

restriction,

The colimn w a s reconnected t o the systen?. w i t h 1 / 2 - i n . -

and S / h - i a . -

GL t u b i n g t o reduce t h e l i k e l i h o o d o f plugging t h e full c r o s s s e c t i o n o f

t h e t r a n s f e r l i n e s with i.ron d e p o s i t s .

I n m l d i i i c l n , a quaatity of

Zircaioy-2 e q u i v a l e n t t o 100 ppm of' zirconium i n bismuth

was d d e d t o

t h e bismuth f e e d t a n k in an a t t e m p t t o i r i l i i b i t mass t r a n s f e r of i r o n .

I n t h e f i n a l hydrodynamic experiment (HR-8) in t h e original. column,

the column flooded a t salt and 'ojsriiuth flow r a t e s of" '75 ml/min. t h e col-mn

HE-5,

Sirice

had o p e r a t e d s a t i s f a c t o r i l y a t t h e s e flow rates during cun

i t was a p p a r e n t t h v t t h e c o n d i t i o n of t h e coliuun had changed.

T h e r e f o r e , the column was removed f o r examixia1,ion and replarmerit

The .Lower half o f t h e colurnn w a s f i l l e d . w i - L h epoxy resin i n o r d e r

t o p r e s e r v e t h e packlng arrangement w h i l e t h e s t e e l p i p e v-as b e i n g

s t r i p p e d %way.

D e n d r i t i c i r o n d e p o s i t s were no-bed i n t h e pxk',ng

(Ftg*

i l c j i n an. amount s u f f i c i e n t t o i n c r e a s e the r e s i s t a n c e t o f l o w , t h a t i s , t o d e c r e a s e t h e throughput at, f l o o d i n g .

The i r o n d e p o s i t s were not

uniformly d i s t r i b u t e d throughout the column bu-t; were located. p r i r n a r i l y

i n t h e lower s e c t i o n .

A i r o x i d a t i o n of the c a r b o n - s t e e l column w a s s e v e r e , = a o i l n t i n g t o

a l o s s o f about 0.050 i n . of w a l l t h i c k n e s s .

The al.uminurn p a i n t a p p l i e d

i n i t i a l l y , which was expected to w i t h s t a n d h i g h t e m p e r a t u r e s

t o have a f f o r d e d l i t t l e p r o t e c t i o n a g a i n s t o x i d a t i o n .

appeared

PHOTO 97581

Fig. 13. Section of Salt Transfer Line Between Salt Jackleg and Column Inlet, Plugged with Dendritic Iron. Darkening of lower specimen occurred during examination, when it was accidentally exposed to air while h o t .

PHOTO 98389

c I

PHOTO 98381

Fig. 14. S e c t i o n of 0.082-in.-ID Column Showing D e n d r i t i c I r o n Deposit (Upper P h o t o g r a p h ) . The lower h a l f o f t h e column w a s p o t t e d i n epoxy r e s i n , and t h e s t e e l p i p e w a s s t r i p p e d away.

SIMULATION OF THE FLOW CONTROL SYSTEMS FOR THE REDUCTIVE EXTRACTION FACILITY C . W. Kee

L . E. McNeese

The s u c c e s s f u l o p e r a t i o n of t h e Reductive E x t r a c t i o n F a c i l i t y (see S e c t . 5 ) depends on a flow c o n t r o l system t h a t w i l l a l l o w s a l t and bismuth flow r a t e s i n t h e f a c i l i t y t o b e q u i c k l y e s t a b l i s h e d a t d e s i r e d v a l u e s and t o be maintained r e l a t i v e l y c o n s t a n t d u r i n g t h e c o u r s e o f an experiment.

Because of t h e importance o f t h i s a s p e c t of o p e r a t i o n ,

a s t u d y o f t h e flow c o n t r o l system i s i n p r o g r e s s .

It has p r e v i o u s l y been shown5 t h a t s t e a d y flow from t h e s a l t and bismuth f e e d t a n k s c a n b e o b t a i n e d i f each phase d i s c h a r g e s a t a c o n s t a n t pressure.

T h i s i s e s s e n t i a l l y t h e c a s e f o r t h e bismuth flow system s i n c e

t h e d i s c h a r g e p o i n t i s a t t h e t o p of t h e e x t r a c t i o n column.

In the case

of t h e s a l t , however, t h e d i s c h a r g e p r e s s u r e i s not c o n s t a n t s i n c e t h e p r e s s u r e i n t h e s a l t j a c k l e g v a r i e s t o match t h a t a t t h e bottom of t h e column.

A t flow rates near f l o o d i n g , changes i n t h e s a l t d i s c h a r g e

p r e s s u r e might b e r a p i d s i n c e p r e s s u r e s u r g e s c o u l d be t r a n s m i t t e d between t h e j a c k l e g and column a t t h e i n h e r e n t r e s o n a n t frequency; t h e s e v a r i a t i o n s c o u l d a f f e c t t h e r a t e s a t which s a l t and bismuth flow t h r o u g h t h e column. It i s t h u s d e s i r a b l e t o s i m u l a t e t h e t r a n s i e n t b e h a v i o r of t h e flow c o n t r o l systems and equipment i t e m s such as t h e j a c k l e g , column, and t r a n s f e r l i n e s , which may a f f e c t o p e r a t i o n of t h e c o n t r o l system.

This

s t u d y w i l l (1) examine t h e s t a b i l i t y of t h e p r e s e n t system, ( 2 ) examine t h e m e r i t s of v a r i o u s o p e r a t i n g methods f o r t h e p r e s e n t system, and

( 3 ) a l l o w e v a l u a t i o n o f proposed equipment m o d i f i c a t i o n s .

Both a n a l o g

and d i g i t a l s i m u l a t i o n s of t h e system have been c a r r i e d o u t and a r e d e s c r i b e d i n t h e remainder o f t h i s s e c t i o n .

6.1

Analog S i m u l a t i o n of J a c k l e g and E x t r a c t i o n Column

For t h i s s i m u l a t i o n a s t e p w i s e change i n bismuth flow r a t e w a s i m -

posed on t h e s i m u l a t e d system, which was o p e r a t i n g a t s t e a d y s t a t e .

rate o f salt flow t o t h e salt j a c k l e g w a s assumed t o remain c o n s t a n t

The

d u r i n g t h e ensuing p e r i o d i n which the l e v e l i n t h e s a l t j a c k l e g and t h e bismuth holdup i n t h e column a d j u s t e d t o the new s t e a d y - s t a t e

values Mathematical A n a l y s i s . - The s t e a d y - s t a t e bismuth holdup i n t h e c o l -

umn w a s assumed t o b e g i v e n by t h e r e l a t i o n

where

H1 = f r a c t i o n of column volume occupied by bismuth a t s t e a d y s t a t e (bismuth holdup)

Vd = dispersed.-phase ( b i s m u t h ) flow r a t e t o column,

'ref

,k ,k,

1 C!

= continuous-phase

( s a l t ) flow r a t e t o c o l w ,

= constants.

The i n s t a n t a n e o u s bismuth holdup i n t h e column w a s assumed Lo change a$

a r a t e p r o p o r t i o n a l t o t h e d i f f e r e n c e between t h e i n s t a n t a n e o u s holdup

and t h e s t e a d y - s t a t e holdup.

Thus, dH

-= dt

(H1 - H),

where

H = i n s t a n t a n e o u s bismuth holdup,

t = time,

k = constant. 3 The pressure at t h e base of t h e column w a s assumed t o result; from t h e s t a t i c pressure of t h e d i s p e r s e d - p h a s e holdup, and from flow of t h e continuous and

d i s p e r s e d phases; t h e dependence w a s assumed t o be as follows :

where

PA = p r e s s u r e a.t t h e base of t h e column, minus t h e s t a t i c pressure when t h e column i s f i l l e d w i t h s a l t ,

4â&#x20AC;&#x2122; 5

= constanLs.

The r a t e of flow o f s a l t between t h e j a c k l e g and t h e colimn was assumed to correspond t o laminar flow i n t h e l i n e connecting t h e two voI.mes

and i s g i v e n as

where

kâ&#x20AC;&#x2122; = constant,,

pressure a t o u t l e t o f j a c k l e g , minus s t a t i c p r e s s u r e of the s a l t i n t h e column.

The change i n p r e s s u r e w i t h -time a t t h e o u t l e t of t h e j a c k l e g i s r e l a t e d t o t h e n e t r a t e of f l . o w from t h e j a c k l e g as

where p =

d e n s i t y of t h e s a l t ,

a = cross-sectional a r e a of jackleg, F

= r a t e a t which s a l t f l o w s t o j a c k l e g .

Scaled Equations and Analog C i r c u i t

Equations (11.)through (15 )

were s c a l e d f o r s o l u t i o n on a n axia.log computer by i n t r o d u c t i o n of t h e following v a r i a b l e s :

= v v c My

wher e h

= s c a l e d s t e a d y - s t a t e holdup,

HTfl = maximum s t e a d y - s t a t e holdup (l.O),

= s c a l e d s a l t f l o w r a t e between t h e j a c k l e g and t h e colimn,

VM = maximum s a l t flow r a t e between t h e j a c k l e g and t h e column (10 ml/sec)

h = s c a l e d i n s t a n t a n e o u s holdup,

HM = maximum i n s t a n t a n e o u s holdup (l-O), PI3

= s c a l e d v a l u e o f p r e s s u r e at j a c k l e g o u t l e t , m i n u s s t a t i c

p r e s s u r e a t b a s e o f t h e column when f i l l e d w i t h s a l t ,

PM = maximum v a l u e o f p r e s s u r e at b a s e of column,minus s t a t i c

p r e s s u r e a t b a s e of t h e column when f i l l e d w i t h s a l t (200 i n .

H*O) 5

pA = s c a l e d value of p r e s s u r e a t t h e b a s e of t h e column,minus s t a t i c p r e s s u r e a t base of t h e column when f i l l e d w i t h s a l t .

T'he r e s u l t i n g e q u a t i o n s are :

Irv

k2Vd hl = +- 1M

-dh- dt

k (h 3 1

v C

h),

klvref

and

A schematic diagram of t h e analog c i r c u i t used f o r s o l u t i o n of Equations

(16)-(20) i s shown i n F i g . 1 5 . Choice of C o n s t a n t s .

- The

v a l u e o f the c o n s t a n t k

( 0 . 1 s e c / m l ) was

chosen such t h a t t h e s t e a d y - s t a t e holdup had a v a l u e of 0 . 1 when V

and ref F0 were each assumed t o have a v a l u e of 1 ml./sec. The c o n s t a n t k 1 w a s given t h e v a l u e of 0 . 0 1 sec/ml- on t h e b a s i s of observed holdup d a t a from t h e mercury-water

system and from t h e s a l t - b i s m u t h system ( S e c t . 15).

v a l u e of t h e c o n s t a n t k

The

approxi-mates t h e r a t i o o f t h e bismuth flow r a t e

through t h e colurnn t o t h e bismuth volume h e l d up i n t h e column, and w a s -1

a s s i g n e d v a l u e s of 0 . 1 and 1 s e c -; t h e v a l u e of 0 . 1 see

-I

i s considered

t o g i v e a more a c c u r a t e r e p r e s e n t a t i o n o f t h e a c t u a l system.

The c o n s t a n t

which w a s assumed t o b e e q u a l t o t h e product of the d i f f e r e n c e i n

d e n s i t i e s o f t h e s a l t and bismuth i n . ) , had a v a l u e of Lo 20 i n .

H20

(6.4 g/cm 3 ) and t h e column h e i g h t (30.25

194 i n . II 20. The c o n s t a n t k 11. w a s v a r i e d from

sec/ml.

0.02

The c o n s t a n t k ' , which r e p r e s e n t s t h e s a l t flow

r a t e ( i n crn3/sec) o b t a i n e d between t h e j a c k l e g and t h e column f o r a p r e s s u r e di'ference

of 1 i n .

B2 0 , was v a r i e d from 0 . 2 t o 1 0 cm3 s a l . t / s e c

i n . H20.

A v a l u e of 0.5 is c o n s i d e r e d t o b e iiiost r e p r e s e n t a t i v e of? t h e a c t u a l system. 2 The c r o s s - s e c t i o n a l area of t h e j a c k l e g w a s v a r i e d from 0 . 2 5 t o 4 i n .

Calculated Results.

R e s u l t s c a l c u l a t e d for a r a n g e of o p e r a t i n g

condritions are shown i n F i g s . 16-1.9. The g r e a t e s t change i n system

0 20,

--I

- - - T - - T

-T

O R N L DWG 7 0 - 11055 R 2

1 ....... ..

Fig. 16. TJariation of Bismuth Holdup in Co1ur.n and Flow of S a l t Retwecii L-ackleg and Column with Time for a k Value of 0.1 and a k' Value 3 of 0.2 in. J 2 G * sec/rnl.

ORNL-DWG-70-11052Rl

4 1 0

-.$ 3

k ' z O . 2 in. H 2 0 - sec/ml

1 15

1 17.5

0.2c

0.15 CI

* 0.IC

c, Holdup Curves

are m m e for a b o v e c 3 s e s

O.O!

1 2.5

1 7.5

1 IO

1 12.5

Time (sec 1

Fig. 17. Variation of Bismuth Holdup in Colurm and Salt Flow Rate Between J a c k l e g and Column with T i m e â&#x201A;Źor k Equal to 1.0 and k' Equal to 3 0.2 in. H 0 * sec/ml.

response w a s produced by v a r i a t i o n o f k

3’

tile r a t e c o n s t a n t f o r d r a i n a g e

of bismuth from t h e column.

R e s u l t s c a l c u l a t , e d f o r t h e most r e p r e s e n t a -

t i v e value of k

and a range of v a l u e s o f k

F i g . 1.6.

3 ( 0 . 1 see-’)

aye shown i n

The s a l t flow r a t e between t h e j a c k l e g and t h e column and t h e

bismuth holdup i n Lhe column are observed t o a d j u s t sxaoothly t o t h e s t e a d y - s t a t e v a l u e s a f t e r an imposed u p s e t i n c o n d i t i o n s . shown i n F i g . 1’9 f o r a k

v a l u e of 1 s e c

d r a i n a g e of bismuth from t h e column.

-1

, which

Results are

r e p r e s e n t s more r a p i d

A s e x p e c t e d , t h e system response

i s f a s t e r and t h e s t e a d y - s t a t e v a l u e s are o b t a i n e d more q u i c k l y .

As i n

t h e former c a s e , t h e system r e s p o n s e was smooth and no o s c i l l a t o r y ’oeh a v i o r w a s observed. t r a n s i e n t behavi-or. k

Changes i n t h e v a l u e o f k

4 had

l i t t l e e f f e c t on t h e

A s shown i n F i g s . 16-18, a n i n c r e s s e i n t h e v a l u e of

r e s u l t e d i n a small d e c r e a s e i n t h e maximum d e v i a t i o n o f Vc from t h e

steady-state value.

A s e x p e c t e d , a n i n c r e a s e i n t h e j a c k l e g diameter (which r e p r e s e n t s

a d e c r e a s e i n t h e r e s i s t a n c e t o flow between t h e j a c k l e g and t h e c o l ~ u m )

r e s u l t e d i n a h i g h e r r a t e of change o f V

C Y

as showia i n F i g . 19. lIowe-rrer,

t h e r a t e of change of t h e bismuth holdup i n t h e column was not a f f e c t e d . The system remained s t a b l e f o r f l o w r e s i s t a n c e v a l u e s much lower t h a n

t h o s e p y e s e n t i n t h e a c t u a l system. Decreases i n t h e c r o s s - s e c t i o n a l area o f t h e j a c k l e g r e s u l t e d i n a more r a p i d r e t u r n of t h e system t o s t e a d y s L a t e , as shown i n F i g . 1 9 .

The system was observed. t o be s t a b l e over t h e range of c r o s s - s e c t i o n a l

areas of 0.25 t o

6.2

in.

n i g i L a 1 S i m u h t i o n of S a l t FLOW C o n t r o l System, J a c k l e g , and Extrac-Lion Column

Although t h e analog sirnulation discussed p r e v i o u s l y i n d i c a t e d t h a t

s a t i s f a c t o r y flow c o n t r o l shcliild be o b t a i n e d w i t h t h e e x i s t i n g equipment,

i t was n e c e s s a r y t o t r e a t s e v e r a l a s p e c t s of t h e system i n a s i m p l i f i e d manner.

T h e r e f o r e , a d i g i t a l s i m u l a t i o n was c a r r i e d o u t i n o r d e r t o

o b t a i n a more r e a l i s t i c r e p r e s e n t a t i o n of t h e system.

Changes i n sim-

47 u l a t i o n of t h e system c o n s i s t e d of t h e f o l l o w i n g :

(1)a material bal-

ance on s a l t and bismuth i n t h e column was s u b s t i t u t e d f o r Eq. ( 2 ) u s e d p r e v i o u s l y t o d e f i n e t h e r a t e o f d r a i n a g e of bismuth from t h e column; ( 2 ) t h e column w a s segmented i n t o s e v e r a l s e c t i o n s t o a l l o w v a r i a t i o n

of flow r a t e s and holdup a t p o i n t s a l o n g t h e column; ( 3 ) more a c c u r a t e

e s t i m a t e s were made of t h e f r i c t i o n a l l o s s e s i n t h e s a l t t r a n s f e r l i n e s (between t h e s a l t f e e d t a n k and t h e jackleg and between t h e j a c k l e g and

t h e column), and t h e diameter of t h e l i n e s w a s v a r i e d ;

( 4 ) simulation

of t h e s a l t flow c o n t r o l system w a s i n c l u d e d ; and ( 5 ) t h e s a l t f e e d p o i n t

l o c a t i o n i n t h e Jackleg relative t o t h e salt level i n t h e jackleg was varied. Three c a s e s were c o n s i d e r e d .

I n Case I t h e s a l t i n l e t t o t h e jack-

l e g w a s l o c a t e d . above t h e s a l t s u r f a c e i n t h e j a c k l e g .

The g a s p r e s s u r e

above t h e s a l t i n t h e j a c k l e g was h e l d c o n s t a n t , and t h e s a l t l e v e l i n t h e j a c k l e g was allowed t o v a r y . I n Case I1 t h e s a l t i n l e t t o t h e j a c k l e g w a s l o c a t e d below t h e s a l t

szlrface i n t h e j a c k l e g .

The gas p r e s s u r e i n t h e j a c k l e g w a s h e l d c o n s t a n t ,

and t h e s a l t l e v e l i n t h e j a c k l e g w a s allowed t o v a r y .

I n Case 111 t h e s a l t

i n l e t t o t h e j a c k l e g was l o c a t e d below t h e s a l t s u r f a c e i n t h e j a c k l e g . The g a s p r e s s u r e w a s v a r i e d i n o r d e r t o m a i n t a i n a c o n s t a n t s a l t l e v e l i n the jackleg. Cases I1 and I11 r e p r e s e n t two p o s s i b l e methods of o p e r a t i o n for t h e

p r e s e n t e x p e r i m e n t a l f a c i l i t y i n which t h e s a l t i n l e t t o t h e j a c k l e g i s l o c a t e d below t h e s a l t s u r f a c e i n t h e j a c k l e g . Mathematical A n a l y s i s of Segnented Column.

- In

t r e a t i n g the extrac-

t i o n column, t h e column w a s d i v i d e d i n t o a number of segments, each of which w a s assumed t o be a t s t e a d y s t a t e d u r i n g a g i v e n time i n t e r v a l .

For t h e i t h segment (numbered from t h e t o p of t h e column), Eq. (11)w a s r e a r r a n g e d t o yrleld t h e f o l l o w i n g r e l a t i o n :

- -Hi Vd il-1 k2 where

,i+l. =

d '

H. 1

- -kl

( 21.)

bismuth flow rate leaving the 5th segment,

fraction of calm-n volume in ith segment occupied by

bismuth

Vc ,i = salt flow rate leaving i t h segment,

kl)k2,Vref = constants.

This equation is similar to the relation used f o r the analog simulat,ion, except that the continuous-phase flow r a t e is important only for f3.ow

rates near flooding.

The relati-onused for determining pressure within the column

segments, similar to Eq. (13), is:

where

P. 1

P. = (kb Hi V c y i + k Ri)/N, 1 5

= pressure a t t h e top of ith seginen-t, miniis pressure due to

static head of salt in column above ith segment,

N = number of segments in column,

k k

4' 5

= constants.

are the same as Values used for the constants kl, k2) k4' k5, and V ref used previously in the anal.og simulation.

A material balance on the dispersed phase in segment i yields the

relation

where

t = time, = volume of column.

%Ol

If one assumes t h a t t h e s a l t and bismuth phases a r e i n c o m p r e s s i b l e , one

obtains the relation

Du-ring a g i v e n t i m e i n t e r v a l , Eqs. ( 2 1 ) t h r o u g h (24) were solved by

t r i a l and e r r o r t o d e t e r m i n e p r e s s u r e , holdup, and f l o w r a t e s throughout A v a l u e was assumed for t h e r a t e of

t h e column i n t h e f o l l o w i n g manner.

s a l t flow from t h e t o p o f t h e column ( t o p segment); t h i s v a l u e was used wLth t h e known flow r a t e a t which bismuth e n t e r s t h e t o p of t h e column t o c a l c u l a t e v a l u e s f o r each column segment.

These v a l u e s i n c l u d e t h e

s a l t flow r a t e i n t o t h e bottom of t h e column (bottom segment) as w e l l

as the p r e s s u r e a t t h i s l o c a t i o n .

The p r e s s u r e v a l u e was t h e n used t o

c a l c u l a t e a v a l u e f o r t h e s a l t flow r a t e between t h e j a c k l e g and t h e

column which c o u l d be compared w i t h t h e c a l c u l a t e d r a t e o f s a l t flow i n t o t h e bottom o f t h e column.

When t h e two v a l u e s d i d n o t a g r e e , t h e

assumed s a l t flow r a t e a t t h e t o p of t h e column w a s a d j u s t e d and t h e c a l c u l a t i o n w a s r e p e a t e d t o o b t a i n a b e t t e r approximation. Mathematical D e s c r i p t i o n of J a c k l e g .

- In

Cases I and I1 t h e p r e s s u r e

above t h e salt s u r f a c e i n t h e j a c k l e g w a s assumed t o be c o n s t a n t s o t h a t changes i n p r e s s u r e a t t h e j a c k l e g o u t l e t were r e l a t e d o n l y t o changes i n t h e l e v e l of s a l t i n t h e jackleg.

Thus, t h e v a r i a t i o n of p r e s s u r e a t

the j a c k l e g o u t l e t w i t h t i m e i s g i v e n by t h e r e l a t i o n

where P

= p r e s s u r e a t j a c k l e g o u t l e t , minus s t a t i c head of s a l t i n t h e column ,

t = time, p =

d e n s i t y of t h e s a l t ,

a = c r o s s - s e c t i o n a l area o f t h e jack.l.eg,

vN-.i.l

= s a l t flow r a t e t o j a c k l e g , = s a l t flow r a t e between j a c k l e g and column.

I n Case I11 t h e pressure above t h e salt s u r f a c e i n t h e j a c k l e g was

c o n t r o l l e d i n a inaniier such t h a t t h e s a l t I.eve1 i n t h e j a c k l e g remained constant.

Hence, t h e p r e s s u r e i n 'the g a s space above t h e s a l t s u r f a c e

i n t h e j a c k l e g w a s t h a t r e q u i r e d t o o b t a i n a s a l t flow r a t e between t h e j a c k l e g and column which was e q u a l t o t h e s a l t flow r a t e t o t h e j a c k l e g The r e s i s t a n c e t o flow between t h e j a c k l e g and column w a s due t o f r i c -

t i o n a l l o s s e s i n t h e l i n e between t h e j a c k l e g and column; t h e mannsr o f c a l c u l a t i n g such losses i s d i s c u s s e d i n t h e f o l l o w i n g s e c t i o n . C a l c u l a t i o n of F r i c t i o n a l Losses i n S a l t T r a n s f e r L i n e s . -The

f r i c t i o n a l l o s s e s in t h e s a l t t r a n s f e r l i n e s ( o n e connecting t h e s a l t

f e e d Lank t o t h e j a c k l e g , and one connecting t h e j a c k l e g to t h e column) were c a l c u l a t e d from t h e P o i s e u i l l e e q u a t i o n f o r l a m i n a r flow a~zdfrom These e q u a t i o n s are g i v e n i n

t h e B l a s i u s e q u a t i o n f o r t u r b u l e n t flow.

( 26) and ( 2 ' 1 ) r e s p e c t i v e l y :

Eqs

(AP)D 128pL

where

Q = s a l t flow r a t e ,

D = diameter of' l i n e ,

p = v i s c o s i t y of s a l t , L = l e n g t h of l i n e ,

AP = p r e s s u r e d i f f e r e n c e , ci.niis s t a t i c head between ends of l i n e ;

and

51 The t r a n s i t i o n between laminar and t u r b u l e n t f l o w w a s assumed t o occur at; a Reynolds number of 2200, where Reynolds number i s d e f i n e d as

I n Case I , s a l t was allowed t o flow o n l y from t h e s a l t f e e d t a n k t o t h e j a c k l e g s i n c e t h e s a l t i n l e t t o t h e j a c k l e g w a s l o c a t e d above t h e s a l t surface i n the jackleg.

For t h e remaining l i n e s , s a l t was allowed t o

flow i n t h e d i r e c t i o n i n d i c a t e d by t h e p r e s s u r e d i f f e r e n c e a c r o s s t h e l i n e i n question. Mathematical D e s c r i p t i o n o f S a l t Flow C o n t r o l System. - A

math-

e m a t i c a l d e s c r i p t i o n o f t h e s a l t flow c o n t r o l system has been g i v e n

p r e v i o u s l y 5 f o r a c o n t r o l l e r having o n l y p r o p o r t i o n a l a c t i o n .

In the

p r e s e n t s i m u l a t i o n , b o t h p r o p o r t i o n a l and i n t e g r a l a c t i o n s were assumed. The f o l l o w i n g r e l a t i o n f o r t h e c o n t r o l a c t i o n w a s used:

where G

B' G

max

= r a t e a t which a r g o n flows t o s a l t f e e d t a n k , = r a t e a t which argon i s b l e d from s a l t f e e d t a n k , p l u s one-

h a l f o f maximum argon f e e d r a t e ,

= maximum argon f l o w r a t e t o f e e d t a n k (1 s t d f t ' / h r ) ,

PE = p r o p o r t i o n a l band,

RT = r e s e t t i m e , min, .t;

vs , s e t

= time, = c o n t r o l l e r set p o i n t g e n e r a t e d by ramp g e n e r a t o r t o r e p r e s e n t

a l i n e a r l y d e c r e a s i n g s a l t volume i n f e e d t a n k ,

Vs = s a l t volume i n f e e d t a n k d u r i n g c u r r e n t t i m e i n t e r v a l .

Calculated Results. - R e s u l t s

cal.culated f o r Case I f o r s e v e r a l jack-

l e g d i a m e t e r s and f o r two s a l t t r a n s f e r l i n e d i a m e t e r s a r e shown i n F i g . 20.

It; i s observed t h a t an u p s e t r e s u l t s i n a r e l a t i v e l y r a p i d response

i n a l l cases.

A s expected, i n c r m s e s i n t h e j a c k l e g diameter r e s u l t i.xi

a slower approach to s t e a d y s t a t e .

more r a p i d w i t h 3 / 8 - i n . - d i m

The approach t o s t e a d y s t a t e i s also

s a l t t r a n s f e r lines t h a n w i t h ,l/l+-in.-diani

lines.

Results c a l c u l a t e d f o r Case I1 a r e shown i n F i g . 21.. The optimum

c o n t r o l l . e r s e t t i n g s appear t o be as f o l l o w s :

proportional. band.,

The u s e o f a gas b l e e d stream from t h e f e e d

and r e s e t tJme, 0.5 min.

t a n k i s seen t o be q u i t e h e n e f i c i - a l s i n c e it al.lows t h e f e e d t a n k p r e s s u r e t o q u i c k l y d e c r e a s e without t h e t r a n s f e r of l a r g e volumes o f

s a l t from t h e f e e d t a n k . R e s u l t s c a l c u l - a t e d f o r Case 111 are shown i n F i g , 22.

Here t h e

approach t o be s t e a d y s t a t e a p p e a r s t o be s l i g h t l y more s l u g g i s h than i n t h e previous cases. Conclusions. - T h e

performance of t h e flow c o n t r o l system a p p e a r s

t o be l i m i t e d by t h e kime requtred. for p r e s s u r i z a t i o n and d e p r e s s u r i z a -

t i o n of t h e g a s space

iri

t h e s a l t reed t a n k .

The b e s t mode o f o p e r a t i o n

appears t o be w i t h a c o n s t a n t gas p r e s s u r e i n t h e s a l t j a c k l e g and w i t h

t h e sal..t i n l e t t o t h e jackleg l o c a t e d above t h e s a l t s u r f a c e i n t h e jack-l e g , as i l l u s t r a t e d by Case I .

However, t h e a , c t u a l system w i l l be

mGre

s l u g g i s h t h a n shown i n Case 1 because considerab1.e t i m e w i l l be r e q u i r e d

f o r t h e f e e d t a n k o u t l e t flow r a t e t o become c o n s t a n t d u r i n g start-up,

even though it i s not a f f e c t e d by v a r i a t i o n s i n Lhe column and s a l t jackleg.

It i s b e l i e v e d t h a t t h e a c t u a l system will f u n c t i o n we1.3. s i n c e

t h e s i m u l a t e d system w a s s t a b l e and performed s a t i s f a c t o r i l y i n a l l the cases considered.

Joikleq Diomrler 2251n \I

-1- ......1 10 15

1..........I... 25

T ~ m t( r e e l

l...~ ...... I . I ........1.......... 45 50 55 60 65

......

ci5

P i g . 20. E f f e c t of J a c k l e g and T'ransfer Line Diameter on F l o w B a t e to Column and Column Holdup. Upper curves are f o r a l/b-in.-diam l i n e , arid lower curves aye for a 3/8-in.-diCm l i n e .

a C U

;

a C

CALIBRATION OF AN ORIFICE--HEAD POT FLOhJMETER WITH MOLYEN SALT AND BISTJUTH 6 , A. h m n a f o r d

C. Id. Kee

Use of an orifice-head

p o t flowmeter, d e s c r i b e d p r e v i o u s l y , 6 i s

being c o n s i d e r e d for d e t c r m i n i n g f l o w r a t e s f o r molten s a l t and bismuth streams i n systems used i n e n g i n e e r i n g development work.

S i n c e t h e fJ-or~.-

m e t e r s under c o n s i d e r a t i o n a r e not of a s t a n d a r d d e s i g n , experimental d e t e r m i n a t i o n o f t h e o r i f i c e d i s c h a r g e c o e f f i c i e n t i s i n p r o g r e s s . 'I

A d d i t i o n n l c a l i b r a t i o n d a t a were obtaj-ned d u r i n g b o t h s t e a d y - s t a t e s n d t r a n s i e n t experiments w i t h molten s a l t and bismuth i n a flowmeter

ha-ving a 0.118-in.-dia.m

Results of t h e s e t e s t s a r e g i v e n i n

orifice.

t h e remainder o f t h i s s e c t i o n ,

The d a t a s u g g e s t t h a t t h e o r i f i c e d i s -

charge chamber. w a s flooded p a r t o f t h e t i m e ; t h i s would prodirce a sig-

n i f i c a n t e r r o r i n t h e measus-ed p r e s s u r e drop across t h e o r i f i c e .

The

remaining d a t a appear t o have been o b t a i n e d under c o n d i t i o n s WheY"e t h e

I n f u t u r e experiiiie:nts, the o r i f i c e - -

d i s c h a r g e chamber was not f l o o d e d .

head p o t and d i s c h a r g e chamber w i l l be p r e s s u r i z e d t o e n s u r e t h a t t h e o r i f i c e d i s c h a r g e chamber does n o t f i l l w i t h Liquid.

7.1.

Data from Steady-State Flow Experiments

Three c a l i b r a t i o n experiments were made i n which a s t e a d y bismuth flow was maintained through t h e m i l d - - s t e e l head p o t , and. one experiment

w a s c a r r i e d o u t w i t h a s t e a d y s a l t flow.

a r e g i v e n i n Tables 3 and

4. The

R e s u l t s from -these experiments

d a t a f o r s a l t flaw appear t o i.ndica.te

t h a t h i g h e r o r i f i c e c o e f f i c i e n t s a r e a s s o c i a t e d w i t h h i g h e r Reynolds

numbers.

The Val-ues f o r t h e o r i f i c e c o e f f i c i e n t a l s o appear t o approach

a c o n s t a n t val-ue n-t high l3eynol.d.s numbers.

d e f i n e d as

cD-AfzGy

'The o r i f i c e c o e f f i c i e n t i s

Table

F1ow Rate (rill ! m in )

3. Orifice Ijischarge C o e f f i c i e n t Data Obtained with Salt Flow During R i m OP-5

132

Ori r i c e

P e r i o d of Ste:idy Flow

278

0.28

8.3

515

0.36 0.37

Reynolds Number a

407

194 245 29 6

Coefficient

0.31r

623

(min)

5.3

4.3

3 .‘7

a Based or? o r i f i c e di:meter.

Tzb.Le

O r i f i . c e Discharge C o e f f i c i e n t Data Obtained w i t h B i s r m t h Flow Flow Rate

(ml/min )

-Fur! ,7L’-

185

12070

182

I 1840

1.27

jp-6

256

330 282

175

222

397 368 a Eased

or1

Reynolds Number a

8283

1.6644 18870 18363

11410 1L4It 0 25830

23940

o r i f i c e diameter.

Orifice

Ccef fI.c ient

0.77 0.68 0.76 0.74 0.8110.81

Period O Y

Steady Flow (minj

3.75

3.7 6.7 1.7 3

8.2

0.734

1.114 0.773

0.773

9 3

whei-e

CD = o r i f i c e c o e f f i c i e n t , Q = l i q u i d flow r a t e ,

p = d e n s i t y of l i q u i d ,

A = c r o s s - s e c t i o n a l area. of t h e o r i f i c e , hP = p r e s s u r e drop a c r o s s o r i f i c e .

Data from t h e experiment w i t h bismuth flow do not show t h e t r e n d

observed w i t h salt flow; however, t h e Reynolds numbers d u r i n g t h e s e ex-

periments are about two orders of magnitude h i g h e r t h a n i n t h e experimen-t

with salt.

One of t h e cal.cula.ted v a l u e s f o r t h e o r i f i c e c o e f f i c i e n t

( l . . l l h ) i s much h i g h e r t h a n expected.

This higher value i s believed t o

b e t h e r e s u l t of t h e o r i f i c e d i s c h a r g e I.ine b e i n g filled w i t h bismu-Lh,

which l e d t o a decreased p r e s s u r e below t h e o r i f i c e .

7.2 Data from T r a n s i e n t Flow Experiments R e s u l t s are shown i n F i g . 23 f o r a n experiment (OP-5) i n which

dyainage o f s a l t from t h e o r i f i c e - - h e a d

p o t was observed.

A s seen i n

e a r l i e r experiments, t h e o r i f i c e c o e f f i - c i e n t a p p e a r s t o d e c r e a s e as the p r e s s u r e drop a c r o s s t h e o r i f i c e d e c r e a s e s .

This i s believed t o r e s u l t

from submergence of t h e o r i f i c e . Some o f -the d a t a o b t a i n e d d u r i n g di-ainage of bismuth from t h e o r i f i c e - head p o t are shown i n F i g . 211.. These d a t a i n d i c a t e lower v a l u e s than expected f o r t h e o r i f i c e c o e f f i c i e n t .

The lower v a l u e s a r e probab1.y caused

by t h e f i l l i n g o f t h e o r i f i c e d i s c h a r g e chamber. The remainder of t h e d a t a o b t a i n e d d u r i n g d r a i n a g e of bismuth from

t h e head p o t i s shown i n F i g . 25. These d a t a a r e b e l i e v e d t o b e more r e l i a b l e t h a n those shown i n Fig.

24.

The values f o r tile o r i f i c e d i s -

c h a r g e c o e f f i c i e n t a r e i n good agreement w i t h t h e expected v a l u e s and w i t h each o t h e r .

E CL

cd I

$ e

2 I

%t (u

0 0 N

‘D

0 a,

E .-

I-

O R N L - OWC-YO-11063

320

1 -

00 + 0 0

a: 40U

D v)

I -

0.5

1.0

1.5

2.5

Time [ niin )

3.0

u 3.5

4 .O

Fig. 2h. Qata Obtained During D r a i n a g e of Bismuth from Orifice-.H e a d P o t Having a n O r i f i c e Diameter o f 0.118 i n .

-(u

ORNL D W G 70-l1056

"E 2 4 0 V \

2Q0

.-V

* I-

0 v, v)

160

a 0 I20 L

n Q, L

a Y-

O 4-

0 0

LIT W

0 3

0.5

P .O

Time (rnin)

1.5

2.o

i. g . 25. Data Obtained During Drainage of Bi.saiuth from O r i f i Bend p o t [laving an G r i . f i c e n i n n i e t e r of 0.118 in. L-,

â&#x201A;Ź2

ELECTROLYTIC CELL DEVELOPMENT :

J . R . Hightower, Jr L. E. McNeese

ST'A'I'IC CELL EXPERIMENTS M. S. Lin

The proposed flowsheet for p r o c e s s i n g a m o l t e n - s a l t b r e e d e r r e a c t o r

recpj.res t h e u s e of e l e c t r o l y t i c c e l l s f o r r e d u c i n g l i t h i m - and thor4im f l u o r i d e s a t a bismuth cathode and for oxiclizing m a t e r i a l s from bismuth s o l u t i o n s a t a bismuth anode.

Two experiments r e l a t e d . t o c e l l develop-

ment were made i n a h-in.-diam

quartz c e l l .

I n t h e f i r s t , c u r r e n t was

passed between two molybdeniim e l e c t r o d e s t o determine whether t h e u s u a l d a r k material wou1.d be formed when bismuth w a s not p r e s e n t i n tile system.

The second experiment was a t e s t o f a porous carbon anode having a much

h i g h e r g a s p e r m e a b i l i t y t h a n t h e g r a p h i t e anode t h a t had been used i n an earl.i.er experiment in which poor r e s u l t s had. been o b t a i n e d .

It was

believed. t h a t a h i g h e r gas p e r m e a b i l i t y might a l l o w removal of the C F

formed a t t h e anode (by flow through t h e g r a p h i t e ) and therreby p r e v e n t

t h e e l e c t r o d e s u r f a c e from b e i n g i n s u l a t e d by a layer o f t h i s materi.al..

The s a l t

(66-34 mo1.e % LiF-BeF,2 ) and bismuth were sparged w i t h H2 b e f o r e

b e i n g t r a n s f e r r e d t o t h e quartz, v e s s e l .

For t h e f i r s t t e s t , t h e d e p t h of s a l t i n t h e c e l l . w a s 3 i n . ; t h e c e l l c o n t a i n e d no bismuth. t o a dep-th of 1 i n .

The anode w a s

I / b i n . - d i a m molybdenim r o d immersed

zt t h e cenLer o f t h e c e l l .

The cathode w a s a 1/4.-in.

molybdenum t u b e i n s e r t e d t o w i t h i n ahout I i n . of t h e bottom of t h e c e l l and l o c a t e d about 1/2 i n . from t h e c e l l wa.l.le A q u a r t z t u b e surrounded

t h e c a t h o d e , and o n l y about 1/h i n . of t h e molybdenum t u b e was exposed

s i n c e i t was t o be used as t h e e 3 . e c t r i c a l l e a d i n t h e second experiment.

I n i t i a l l y , an a l t e r n a t i n g c u r r e n t o f about 2

A w a s passed between t h e

e l e c t r o d e s f o r approximately 2 min w i t h a c e l l t e m p e r a t u r e of approximately 600Oc.

A t t h e end of t h i s t , i m e , a small anounl; of black m a t e r i a l vas ob-

served near t h e e l e c t r o d e having the q u a r t z s h e a t h around i t .

c u r r e n t o f about 5 A w a s then passed between t h e e l e c t r o d e s .

A direct

There was

a r a p i d formation o f b l a c k m a t e r i a l i n t h e v i c i n i t y o f tine anode, and t h e

s a l t became opaque w i t h i n 1 min.

A f t e r s t a n d i n g o v e r n i g h t , most of t h e

material had s e t t l e d o u t , a l t h o u g h a f e w l a r g e p a r t i c l e s ( W 8 i n . i n d i a m e t e r ) were s t i l l . suspended i n t h e s a l t phase.

Current

( 5 A, d c )

w a s a g a i n p a s s e d , arid t h e c e l l r a p i d l y became opaque a g a i n ; t h e b l a c k m a t e r i a l t h a t formed a t t h e anode r o s e a l o n g t h e anode, s p r e a d o u t a t t h e s a l t su.rface, and d i s p e r s e d throughout t h e s a l t from t h e s u r f a c e . A.nalysis o f some of t h e s o l i d m a t e r i a l suspended i n t h e s a l t i n d i c a t e d t h a t s i l i c o n might have been p r e s e n t .

It w a s concluded from t h i s e x p e r i -

ment t h a t t h e p r e s e n c e o f bismuth i s n o t n e c e s s a r y f o r f o r m a t i o n of t h e black r a t e r i a l . A f t e r t h e t e s t w i t h t h e molybdenum e l e c t r o d e s , s u f f T c i e n t bismuth

w a s t r a n s f e r r e d t o t h e c e l l t o produ-ce a 3 - i n . d e p t h of t h i s m e t a l , and t h e molybdemm r o d a t t h e c e n t e r of t h e c e l l w a s r e p l a c e d w i t h a 1 - i n . diam porous carbon e l e c t r o d e ( d e n s i t y = 0 . 1 g / c c ) immersed t o a d e p t h

of 1 i n . i n t h e s a l t . With t h e c e l l a t 600째C,

a p o t e n t i a l of 5 V was a p p l i e d between t h e

bismuth cathode and t h e carbon anode.

The i n i t i a l c u r r e n t , approximately

A , decayed r a p i d l y t o a s t e a d y v a l u e of about 0.2 A ( c o r r e s p o n d i n g t o

a c u r r e n t d e n s i t y of 0.04 A/crn2, based on t h e area o f t h e end o f t h e carbon a n o d e ) .

The e e l 1 was t h e n evacuated t o an a b s o l u t e p r e s s u r e of

l e s s t h a n 29 i n . Hg w i t h o u t a f f e c t i n g t h e c u r r e n t d e n s i t y .

Sparging t h e

c e l l p e r i o d i c a l l y produced s h o r t - t e r m i n c r e a s e s i n c u r r e n t , but c o n t i n u o u s sparging d i d not h e l p appreciably.

If t h e CF

had escaped from t h e carbon

r e a c t i o n s u r f a c e a t a r a t e l i m i t e d o n l y by r e s i s t a n c e t o g a s flow t h r o u g h t h e porous e l e c t r o d e , a c u r r e n t d e n s i t y of 1 2 t o 29 A/cm obtained.

would have been

A p p a r e n t l y , a n i n s u l a t i n g f i l m of gas w a s formed on t h e anode.

A l t e r n a t i v e l y , w i t h such a h i g h p e r m e a b i l i t y , t h e s a l t may have p e n e t r a t e d t h e e l e c t r o d e a short d i s t a n c e , t h u s i s o l a t i n g t h e r e a c t i o n s u r f a c e from

t h e s a l t - f r e e porous carbon and n u l l i f y i n g t h e b e n e f i t of t h e low r e s i s t a n c e t o g a s flow o f f e r e d by t h i s material. We a r e c o n t i n u i n g experi-nients i n s t a t i c c e l l s i n o r d e r t o i d e n t i f y the b l a c k material.

We a r e i n s t a l l i n g a n all-metal c e l l -to determine whether

t h e m a t e r i a l forms i n t h e absence of s i l i c a .

64 9.

ELECTROLYTIC cmr, DEVELOPMENT: FORMATTON OF FROZEN FITIMS WITH AQUEOUS ELECTROLYTES J . R. Hightower, J r .

C . W . Kee

Formation of f r o z e n s a l t f i l m s on s t r u c t u r a l s u r f a c e s exposed t o tlie m o l t e n - s a l t e l e c t r o l y t e i n c e l - l s is b e i n g c o n s i d e r e d as a means f o r pro-

t e c t i n g t h e s e surfaces from c o r r o s i o n by BiF. produced a t t h e cell. anode. 3 A s t u d y of f r o z e n film foymation under c o n d i t i o n s s i m i l a r t o t h o s e ex-pected i n a c e l l i s i n progress.

Part, of t h e work w i l l b e c a r r i e d o u t

u s i n g an aqueous e l - e c t r o l y t e i n o r d e r t o avoid problems a s s o c i a t e d w i t h

m o l t e n salt--bismuth

systems.

Equipment h a s been i n s t a l l e d f o r s t u d y i n g t h e f o r m a t i o n o f i c e f i l m s on s u r f a c e s of a s i m u l a t e d e l e c t r o l y t i c c e l l t h a t u s e s a n aqueous s o l u t i o n r a t h e r t h a n molten s a l t as t h e e l e c t r o l y t e .

A l t e r n a t i n g current w i l l be

used t o minimize t h e e f f e c t s o f elec-Lrode reac-Lions and. mass t r a n s f e r .

The rernainder o f t h i s s e c t i o n will d e s c r i b e t h e equipment t h a t has

been b u i l t , and outI.ine a mathematical a n a l y s i s f o r u s e i n d e s i g n i n g c e l l s and i n t e r p r e t , i n g r e s u l t s .

9 . 1 Mathematical Anal.ysis

- One

Average Current D e n s i t y _ a n d Power D i s s i p a t i o n .

conceptual

d e s i g n f o r an e l e c t r o l y - t i c c e l l c o n s i s % s of flowing molten bismuth electrod.es ( a l t e r n a t e l y anodic and cat1iodi.c ) i n long, narrow t r a y s

t h a t are c l o s e l y spaced and a r e submerged i n t h e e l e c t r o l y t e .

The

d i v i d e r between t h e e l e c t r o d e s inus-L be e l e c t r i c a l 1 . y i n s u l a t i n g , and t h e t o p edge o f it must be pro.tected from c o r r o s i o n by a f l . I m of

frozen s a l t . F i g u r e 26 i s a diagram of a half-anode--half-cathode

combination

and shows a conveni-en-L i d e a l i z a t i o n of an a c t u a l c e l l t h a t w i l l be ? x e d i n c e l l design.

The c u r r e n t i s assumed t o be c o n f i n e d t o an e l e c t r o l y t e

r e g i o n bounded by t h e f r o z e n f i l m a t a r a d i u s of

and by a h y p o t h e t i c a l

I-

66 insiil.ating s u r f a c e a t a r a d i u s of r electrode t r a y ) .

2 (which i s h a l f t h e width of a n

A c o o l i n g t u b e of r a d i u s r

i s positioned a t t h e

t o p of t h e e l e c t r o d e d i v i d e r and i s covered w i t h a f r o z e n f i l m of thickness r insulating.

The c o o l i n g t u b e i s assumed t o be e l e c t r i c a l l y

The c u r r e n t d e n s i t y i n t h e conductirlg r e g i o n i s g i v e n by Ohm's

1-aw as:

where

3 = v e c t o r c u r r e n t d e n s i t y , A/m

E = v e c t o r e l e c t r i c f i e l d s t r e n g t h , V/m, ohm-l -1 g = conductivi.ty o f t h e e l - e c t r o l y t e , m

With no s o u x e s of emf i n t h e conducting r e g i o n , t h e f i e l d s t r e n g t h i s d e r i v a b l e from a s c a l a r p o t e n t i a l : 8

E = -grad U>,

(32)

-f

where U = electric potential, V,

grad U = gradient of U. I n c y l i n d r i c a l p o l a r c o o r d i n a t e s , Eq. ( 3 2 ) becomes

-f

= (a - + a -+

r ar

--), 0 r 36

(33)

+ -+ r and 2 d i r e c t i o n s r e s p e c t i v e l y . where a and a a r e u n i t v e c t o r s i n t h e r 0 S u b s t i t u t i o n of E q . ( 3 3 ) i n t o E q . (31) yie1.d.s t h e r e l a t i o n

I n t h e c o n d u c t i n g r e g i o n , i f one assumes t h a t g i s c o n s t a n t ,

t h e po-

t e n t i a l U satisfies t h e d i f f e r e n t i a l equation 2

V TJ = 0 ,

(35 1

which may be s t a t e d i n c y l i n d r i c a l p o l a r c o o r d i n a t e s as f o l l o w s :

a ( r 5) au + -a2u = ar

ae2

(36)

The boundary c o n d i t i o n s assumed for t h e model shown i n F i g . 26 are: 1.

The radial c u r r e n t component a t r = r

The r a d i a l c u r r e n t component r

The p o t e n t i a l a t t h e anode

= Vl

(1 -

i s 0 , so t h a t

= 0 ) is V

a t t h e c a t h o d e ( 0 = n ) is 0 .

Equation (37 ) ,

and t h e p o t e n t i a l

0 --I,

(37)

< r L r 2 and 0 < e < IT/^ (36) in t h e r e g i o n r1 end s a t i s f i e s t h e boundary c o n d i t i o n s . S u b s t i t u t i o n of Eq. (37) i n t o j s a s o l u t i o n t o Eq.

Pq. ( 3 4 ) r e s u l t s i n t h e f o l l o w i n g e q u a t i o n f o r c u r r e n t d e n s i t y :

From Eq. (38)

it; c a n be seen t h a t c u r r e n t f l o w s o n l y i n t h e a n g u l a r

d i r e c t i o n ; t h e r a d i a l component i s everywhere z e r o .

T h i s r e l a t i o n will

be used t o c a l c u l a t e t h e average c u r r e n t d e n s i t y i n t h e c e l l and t o c a l c u l a t e t h e power Loss due t o t h e r e s i s t a n c e of t h e e l e c t r o l y t e .

68 The power l o s s can be c a l c u l a t e d by i n t e g r a t i n g t h e s p e c i f i c power d i s s i p a t i o n over t h e volume of t h e c e l l .

The s p e c i f i c power d i s s i p a t i o n

i s g;iven by:

P = 1.g J2, i n w/m 3 , where J i s t h e magnitude o f t h e c u r r e n t d e n s i t y ; and t h e t o t a l power d i s s i - p a t i o n i s g i v e n by

p dV,

where V i s t h e volume of t h e r e g i o n c a r r y i n g c u r r e n t .

P2 3 d r

d e n s t t y i s g i v e n by

Javg = r where R

= (r2

- r1

The average c u r r e n t

gV I

.irR

(41.)

r l ) / l n (r /r ). 2

The power d i s s i p a t e d i n t h e c e l l i s c a l c u l a t e d from Eq. ( 4 0 ) and i s g i v e n by :

(42) where H

avg

= 1/2(r2 +

rl).

~f a c o o l a n t a t temperature T

( T ~< T f , t h e f r e e z j n g t e m p e r a t u r e of

t h e e l e c t r o l y t e ) flows t h r o u g h t h e c o o l i n g t u b e a l o n g t h e e l e c t r o d e d i v i d e r ,

a f r o z e n f i l m w i l l form and grow u n t i l t h e t o t a l r e s i s t a n c e t o h e a t flow

f r o m t h e b u l k of t h e e l e c t r o l y t e c a u s e s t h e r a t e a t which h e a t flows into

t h e t u b e t o be e q u a l to t h a t a t which h e a t i s c a r r i e d away by t h e c o o l a n t . A t s t e a d y s t a t e , t h e h e a t c a r r i e d away wi1.1. b e e q u a l t o t h a t g e n e r a t e d i n

the b u l k of t h e e l e c - t l ' o l y t e , mi.nus t h a t l o s t through o t h e r s u r f a c e s ( e . g . , t h e t o p s u r f a c e of t h e e l e c t r o l y t e ) .

For t h e s e c a l c u l a t i o n s , w e w i l l

assume t h a t a known f r a c t i o n of h e a t g e n e r a t e d i n t h e semiannular r e g i o n and r ( s e e F i g . 26) i s removed through t h e c o o l i n g t u b e . We 1 2 w i l l assume t h a t a l l h e a t flow through t h e f r o z e n f i l m and t u b e w a l l i s between r

i n the radial direction.

W e w i l l a l s o assume t h a t t h e r e s i s t a n c e t o h e a t

flow through t h e t u b e wall and t h r o u g h t h e c o o l a n t i s n e g l i g i b l e when

compared t o t h e r e s i s t a n c e t o h e a t f l o w through t h e f r o z e n f i l m on t h e outside of the tube,

Under t h e s e assumptions, t h e e q u a t i o n r e l a t i n g t h e

frozen film thickness t o t h e heat generation i s :

where Q = h e a t t r a n s f e r r e d through t h e frozen f i l m , W,

L = l e n g t h of c o o l i n g t u b e , cm, T~ = f r e e z i n g t e m p e r a t u r e of e l e c t r o l y t e ,

Oc,

k = t h e r m a l c o n d u c t i v i t y of t h e f r o z e n f i l m , IJ/째C-cm,

'rC r

= t e m p e r a t u r e of c o o l a n t ,

Oc,

= o u t s i d e r a d i u s of c o o l a n t t u b e , cm,

t = f r o z e n f i l m t h i c k n e s s , em.

Equations (hl), ( I - c ~ ) , and ( 4 3 ) a r e o n l y approximate and. t h u s c a n be

u s e d only as guides i n t h e d e s i g n of equipment and f o r p r e d i c t i n g i t s performance

9.2 Coolant System. - A P i g . 27.

Experimental Equipment flow diagram of t h e c o o l a n t system i s shown i n

T h i s system c o n s i s t s of c o o l i n g t u b e s ( t h a t p a s s through t h e

e l e c t r o l y t i c c e l l ) f o r removing h e a t from t h e c e l l , a c h i l l e r for removing

t h i s h e a t from t h e system and c h i l l i n g t h e c o o l a n t ( t r i c h l o r o e t h y l e n e )

below t h e f r e e z i n g p o i n t of w a t e r , a pump t o r e c i r c u l a t e t h e c o o l a n t , and

71 flowmeters and valves t o c o n t r o l t h e flow.

There are t h r e e c o o l a n t c i r -

c u l a t i n g loops t h a t a l l o w t h e t e m p e r a t u r e o f t h e c o o l a n t a t t h e c e l l i n l e t and t h e flow r a t e o f t h e c o o l a n t t h r o u g h t h e c e l l t o b e a d j u s t e d indepeadent ly

The c h i l l e r c o n s i s t s of a 55-gal s t a i n l e s s s t e e l drum c o n t a i n i n g a

c o i l made o f 50 f t o f 3/4-in.-diam i n a trichloroethylene--dry

a t l e a s t as Low as -5O*C.

copper t u b i n g .

The t u b i n g i s immersed

i c e b a t h , t h e t e m p e r a t u r e o f which should b e

Dry i c e w i l l be added a t a r a t e of 0.24 l b p e r

minute p e r k i l o w a t t o f h e a t g e n e r a t e d by t h e c e l l and pump.

Experimental C e l l Vessel.-- The f i r s t c e l l v e s s e l t o be used i n t h e s e experiments i s made of P l e x i g l a s and c o n t a i n s two t r a y s 1 2 i n . l o n g x 2 i n . d e e p ) s e p a r a t e d by a l / b - i n . - t h i c k

w i l l c o n t a i n mercury pools f o r e l e c t r o d e s .

(1-7/8 i n a

wide

divider; t h e trays

A diagram of t h e c r o s s s e c t i o n

of t h e c e l l i s shown i n F i g . '28; a photograph of t h e c e l l v e s s e l i n s t a l l e d

i n t h e c o c l i n g l o o p i s shown i n F i g . 29.

The wider s e c t f o n s a t each end

OS t h e c e l l v e s s e l accommodate i n s t a l l a t i o n o f t h e c o o l i n g t u b e s .

The

maximum h e a t g e n e r a t i o n r s t e o f i n t e r e s t c o r r e s p o n d s t o a n average c u r r e n t d e n s i t y of

5 A/cm2 i n molten s a l t having a r e s i s t i v i t y

16-12 mole

0.65 o h - c m

('72-

LiF-BeF2-ThFlc) a t 600"~. For ICBr o r KI s o l u t i o n s (27 zlnd 33

w t $, r e s p e c t i v e l y ) a r e s i s t i v i t y of about

a f r e e z i n g p o i n t of -1O'C.

8 o:m-cm can h e o b t a i n e d w i t h

With t h e s e s o l u t i o n s , t h e h e a t g e n e r a t i o n r a t e

of" i n t e r e s t cou.1d be o b i a i n e d w i t h an average c u r r e n t d e n s i t y of about 1.5 A/cm 2 C a l c u l a t i o n s show t h a t , i f t h i s h e a t i s removed through t h e

e l e c t r o d e d i v i d e r c o o l i n g t u b e , an i c e f i l m having a t h i c k n e s s of o n l y

about 0.05 i n . w i l l f o m .

Consequently, o t h e r c o o l i n g t u b e s were added

a l o n g t h e walls of t h e c e l l v e s s e l t o reduce t h e h e a t load on each t u b e .

I n an a c t u a l e l e c t r o l y t i c c e l l

p r o t e c t i o n also.

9.3

t h e s e s u r f a c e s would r e q u i r e c o r r o s i o n

Expected Mode of O p e r a t i o n

Temperature measurements of t h e e l e c t r o l y t e , e l e c t r o d e s , and c o o l a n t

f l u i d , and measurements o f c u r r e n t and v o l t a g e , w i l l be made i n o r d e r t o

b DWG '70-4541

AQUEOUS ELECTROLYTE SOLUTION

-COOLING TUBES

Fig. 28. D i a g r a m of Cross S e c t i - o n of Electrclytic Cell to Ae Used w i t h Aqueous Electrolytes i n Stud3-ing F o r m a t i o n o f Ice F i l m s .

74 make energy b a l a n c e c a l c u l a t i o n s on t h e system.

Measurements of t h e

amount of h e a t t h a t i s removed by each c o o l i n g t u b e should a i d i n d e t e r m i n i n g h e a t g e n e r a t i o n rates a t v a r i o u s p o i n t s i n t h e c e l l . The c e n t e r t u b e w i l l have t h e g r e a t e s t h e a t removal r a t e and t h e thinnest i c e f i l m .

Observations o f f r o z e n f i l m t h i c k n e s s , shape, and

s t a b i l i t y w i l l b e made.

I n a d d i t i o n , q u a l i t a t i v e o b s e r v a t i o n s w i l l be

made of t h e b e h a v i o r o f t h e i c e l a y e r below t h e s u r f a c e of t h e m e t a l electrodes.

10. DEVELOPMENT OF A BISMUTH--MOLTEN SALT INTERFACE DETECTOR J . Roth

L. E. McNeese

An i n t e r f a c e d e t e c t o r based on t h e p r i n c i p l e of eddy c u r r e n t generat i o n i n l i q u i d metals i s b e i n g developed f o r u s e a t molten s a l t - - l i q u i d bismuth o r gas-liquid

bismuth i n t e r f a c e s .

It i s d e s i r e d t h a t a l l s u r f a c e s

c o n t a c t i n g bismuth be made o f a r e f r a c t o r y metal such as molybdenum; however, t h e s e materials have a r e l a t i v e l y low e l e c t r i c a l p e r m e a b i l i t y , which makes t h e i r use d i f f i c u l t .

The d e v i c e under development i s a m o d i f i c a t i o n of a

l i q u i d - l e v e l i n d u c t i o n probe developed a t Argonne N a t i o n a l Laboratory 9 and h a s been d e s c r i b e d p r e v i o u s l y . â&#x20AC;?

The d e s i g n of t h e i n d u c t a n c e c o i l

h a s been modified so t h a t a l l l e a d wires are a c c e s s i b l e from one end; t h i s s i m p l i f i e s t h e replacement o f l e a d w i r e s . 10.1

T e s t i n g and M o d i f i c a t i o n of E l e c t r o n i c C i r c u i t P r i o r t o I n s t a l l a tion

I n i t i a l t e s t i n g of t h e e l e c t r o n i c c i r c u i t p r i o r t o i n s t a l l a t i o n e s t a b l i s h e d t h e need f o r several m o d i f i c a t i o n s .

An a t t e m p t w a s made t o

e s t a b l i s h component c o m p a t i b i l i t y u s i n g t h e expected materials of construction.

Core m a t e r i a l s t e s t e d i n t h e i n d u c t a n c e c o i l i n c l u d e d aluminum,

Woods m e t a l , and bismuth, i n a i r , i n a 304 s t a i n l e s s s t e e l s i g h t tube,and i n the required

347 s t a i n l e s s steel--molybdenum duplex s i g h t t u b e

On l o a n from Combustion Engineering.

that is

75 d e s c r i b e d below.

The m o d i f i c a t i o n s involved changes i n s i g n a l ampli-

f i c a t i o n , as w e l l a s s t a b i l i z a t i o n of t h e s i g n a l r e c e i v e d from t h e detection coil.

The e l e c t r o n i c a m p l i f i c a t i o n f a c t o r w a s f i r s t i n c r e a s e d by a f a c t o r

of 1 0 , which %hen n e c e s s i t a t e d replacement of t h e dc a m p l i f i e r w i t h one g e n e r a t i n g a "(:leaner"

signal.

A f t e r t h e s e m o d i f i c a t i o n s had been com-

p l e t e d , it w a s found t h a t , w i i h t h e 347 s t a i n l e s s steel--molybdenum

sight

Lube, i n s e r t i o n o f a Woods metal r o d i n t o t h e c o i l caused a pen d e f l e c t i o n of 90% of f u l l s c a l e ,

I n s e r t j o n o f a bismuth r o d i n t o t h e c o i l caused a

pen d e f l e c t i o n o f o n l y

24% of

F u l l s c a l e ; however, t h i s d e f l e c t i o n i s

b e l i e v e d t o be s u f f i c i e n t l y h i g h if t h e s i g n a l - t o - n o i s e increased.

r a t i o can be

Toward t h i s end, several a d d i t i o n a l m o d i f i c a t i o n s were made.

All e l e c t r i c a l lead wires were s h i e l d e d .

The d e t e c t o r c o i l w a s s h i e l d e d

from t h e f u r n a c e element by a sched 40 t y p e 347 s t a i n l e s s s t e e l p i p e , which e s s e n t i a l l y e l i n i i n a t e d induced s i g n a l s g e n e r a t e d by t h e f u r n a c e element.

A I 1 segments of t h e e l e c t r o n i c c i r c u i t were connected t o a common ground,

which reduced t h e s i g n a l v a r i a t i o n s caused by d i r f e r i n g ground p o t e n t i a l s . Al.1 e l e c t r o n i c components, w i t h t h e e x c e p t i o n of t h e f u r n a c e element, were

connectcd t o a l-kva

Sola constant-voltage transformer.

F i n a l t e s t i n g of

t h e system at room t e m p e r a t u r e r e v e a l e d t h e p r e s e n c e o f a 2-V impressed s j g n a l t h a t ( c o u l d n o t be e l i m i n a t e d e l e c t r o n i c a l l y .

T h i s s i g n a l w a s found

t o be dependent on l e a d w i r e l o c a t i o n and was e l i m i n a t e d by p ~ o p e r -p l a c e -

ment of t h e l e a d w i r e s .

Upon completion of t h i s phase of t h e work, it was

found t h a t n o i s e l e v e l had been reduced from about 20% of f u l l s c a l e t o

&out

6% of f u l l s c a l e .

T e s t i n g o f t h e system a t t e m p e r a t u r e s above room t e m p e r a t u r e w a s

t h e n s t a r t e d by f Y r s t h e a t i n g t h e coil s l o w l y t o about ?5OoC i n an

a t t e m p t t o dl-y o u t t h e d e t e c t o r c o i l and t o determine t h e e f f e c t s o f b o t h

h e a t and c u r r e n t flow t h r o u g h t h e f u r n a c e c o i l s on bhe d e t e c t o r c o i l .

f o l l o w i n g c o n c l u s i o n s were drawn as a result of these t e s t s : 1.

Loss o f ground c o n n e c t i o n t o t h e s t a i n l e s s s t e e l f u r n a c e s h i e l d caused a pen d e f l e c t i o n o f 9% o f f u l l s c a l e .

i n d i c a t e s t h e need for good ground c o n n e c t i o n s on a l l

p o r t i o n s o f t h e system,

This

The

The r e c o r d e r r e s p o n s e s r e s u l t i n g from f u l l inser-Lion of a bismuth rod i n t o t h e det,ector c o i l were

11%

and 20% o f f u l l

s c a l e a t mom t e m p e r a t u r e and a t 220째C, r e s p e c t i v e l y . These d a t a i n d i c a t e t h a t t h e s e n s i t i v i t y of t h e s y s t a i i n c r e a s e s w i t h i n c r e a s i n g tempera-t-ure and t h a t a f u l l - s c a l e pen d e f l e c t i o n might be

observed at. t h e 0pera.tin.g t e m p e r a t u r e of 600째C.

However, t k e l e c t r i c a l

p r o p e r t i e s of bismu-Lh e x h i b i t a d i s c o n t i n u i t y a t t h e m e l t i n g p o i n t , which

It w a s d e c i d e d t o modify t h e e l e c t r o n i c

may d e c r e a s e t h e s e n s i t i v i t y .

c i r c u i t such t h a t t h e o u t p u t stgnal. w i l l . b e a;mpl.ified by an a d d i t i o n a l f a c t o r o f 10, The opiirnum c o i l o p e r a t i n g frequency i n c r e a s e s w i t h i n c r e a s i n g t e m p e r a t u r e ; however, t h e corresponding o u t p u t s i g n a l d e c r e a s e s with i n c r e a s i n g frequency. frequency.

I n a d d i t i o n , t h e e l e c t r o n i c z e r o i s a l s o dependent on the

A t room t e m p e r a t u r e , t h e optimum frequency w a s

o u t p u t o f 8 V was observed.

A t 450 t o 5OO0C t h e optimum fr.eqi.iency was

59 kIIz, w i t h a corresponding o u t p u t of 6 V .

over a p e r i o d of t i m e .

47 kHz, and

The e l e c t r o n i c z e r o d r i f t e d

A Zener d i o d e feedback c i r c u i t w i l l be i n s t a l l e d

i n t h e system i n a n a t t e m p t t o s t a b i l i z e i t . 10.2

F a b r i c a t i o n of S i g h t Tube

The second a t t e m p t by t h e Me'Lals and Ceramics D i v i s i o n t o c o a t t h e i n t e r n a l s u r f a c e of a O.5OO-in.-diam

ty-pe 347 s t a i n l e s s s t , e e l t u b e w i t h

0.005 .Lo 0.010 i n . of t u n g s t e n by chemical vapor d e p o s i t i o n was successful.

However, r e p e a t e d a t t e m p t s t o c o a t t h e e x t e r n a l s u r f a c e of t h e t u b e

f a i l e d because of an i n a b i l i t y t o produce a c o n t i n u o u s bond between t h e i n t e r n a l and e x t e r n a l c o a t i n g s .

F a i l u r e of t h i s t e c h n i q u e

'LO

establish

a s u i t a b l e bond between the two s u r f a c e c o a t i n g s was a t t r i b u t e d to the

high s t r e s s l e v e l s t h a t are i n h e r e n t w i t h t h i s t y p e o f j o i n t .

These

s t r e s s l e v e l s a r e caused p a r t i a l l y by t h e d i f f e r e n t i a l t h e r m a l expansion c h a r a c t e r i s t i c s of t u n g s t e n and s t a i n l e s s s t e e l and partia.1I.y by t h e f a i l u r e o f t h e vapor-deposited t u n g s t e n t o bond t o t h e s t a i n l e s s s t e e l substrate.

t h i s method.

No f u r t h e r a t t e m p t s w i l l be made t o p r e p a r e si.ght t u b e s by

77 The s i g h t t u b e s r e q u i r e d f o r t h e t e s t a p p a r a t u s have been produced by machining tlie e x t e r n a l s u r f a c e s of s e v e r a l 36-in.-long

p i e c e s of

molybdenum t u b i n g , which were o r i g i n a l l y 0,375 i n . OD w i t h a 0.040-in. w a l l , t o produce a w a l l t h i c k n e s s of 0.02 i n .

Although t h i s t h i c k n e s s

i s considerably greater than anticipated, tests indicate t h a t s a t i s f a c t o r y

r e s u l t s can s t i l l be o b t a i n e d .

COMTINUOUS SALT PURIFICATION

R. B. Lindauer E . 1,. Youngblood L. E . McNeese Molten s a l t f o r t h e MSRE and f o r development work i s p r e s e n t l y p u r i f i e d from contaminants (mainly s u l f i d e s , o x i d e s , and iron f l u o r i d e ) by a

b a t c h process."

The t o t a l . c o s t of s a l t ( n a t u r a l l i t h i u r n ) t h u s produced

has m o u n t e d t o about $1600/ft3, o f which l e s s t h a n 40% i s m a t e r i a l c o s t ,

In - 4 p r i l 1968, a commercial vendor b i d $ 2 6 6 0 / f t -3 on a 280-ft 3 q u a n t i t y .

It i s b e l i e v e d t h a t t h e labor c o s t s c o u l d be reduced c o n s i d e r a b l y by use

or" a continuous p r o c e s s for t h e most time-consuming o p e r a t i o n (hydrogen r e d u c t i o n of i r o n f l u o r i d e ) .

Although t h e removal of s u l f i d e s and oxides

by t h e b a t c h p r o c e s s is f a i r l y r a p i d , a 4 d i t i o n a l advantages would probably b e g a i n e d by performing t h i s o p e r a t i o n c o n t i n u o u s l y . P r e l i m i n a r y experiments on t h e r e d u c t i o n of i r o n f l u o r i d e i n molten

s a l t weye performed by MIT P r a c t i c e School s t u d e n t s i n 1968 w i t h encouraging

results.

A s u b s t a n t i a l r e d u c t i o n i n t h e c o n c e n t r a t i o n of i r o n f l u o r i d e w a s

o b t a i n e d , a l t h o u g h most of t h e o p e r a t i o n w a s c a r r i e d o u t a t l e s s t h a n 2% o r the calculated flooding rate.

For t h e p r e s e n t s t u d i e s , t h e column d i a m e t e r

has been reduced from 3.375 i n . t o 1.38 i n . ( 1 . 2 5 - i n . , al-low o p e r a t i o n nearez. t h e f l o o d i n g point;. i s packed w i t h

1 / 4 - i n . Haschig r i n g s .

supply p u r i f i e d hydrogen, a r g o n , and t o o p e r a t e a t t h e higher r a t e s .

the system.

sehed

40 p i p e )

The column is 81 i n . l o n g and

Equipment h a s been designed t o

HF gas i n s u f f i c i e n t q u a n t i t i e s

Figure 30 i s a s i m p l i f i e d flowsheet of

Molten s a l t i s charged Co tlie r e c e i v e r t.ank and t h e n t r a n s -

f t , r r e d v i a p r e s s u r i z a t i o n t o t h e f e e d t a n k , which 5s e l e v a t e d about 5-1/2

f t t o red.uce

t h e argon p r e s s u r e r e q u i r e d t o r e e d s a l t t o t h e coli.lmn.

The s a l t feed r a t e i s eon-troll.ed by a d j u s t i n g the argon flow rz1;e t o

I n o r d e r t o 1.imi.t t h e s t r e s s on t h e f e e d t a n k , the t a n k

t h e feed. t a n k .

i s m a i n t a i n e d a t 650Oc; a d d i t i o n a l h e a t i s supplled t o i : ? ~ feed l i n e t o

i n c r e a s e the t e m p e r a t u r e o f t h e s a l t t o t h e coliunn o p e r a t i n g teniperature

of 700°C.

The hydmgen i s also preheat;ed to 700°C b e f o r e 3 . t e n t e r s t h e

bottom of t h e c o l m n . throug!i

Hydrogen I.ea7ii.ng t h e t o p of’ t h e coli:.mn

flows

p r e s s w e c o n t r o l valve in order to m a i n t a i n t h e t;a.l.t-gss

f a c e a t t h e bottom. of t h e eal.imn below the gas i n l e t .

bottom of t h e colunn passes

first

inter-

Sa1.t l e a v i n g t h e

through a liqii..id. s e d l a o g and, t h e n ,

t’mo~ighEL f i h r o u s m e t a l filter t o remove p a r t i c u l z t e i r o n

The f i l t e r e d

salt p a s s e s t’nro1.1.gh a. flowing s-tiremfi ss..mpler anci i s sii’oseqiuenLly r o u t e d

t o the r e c e i v e r

Bydrogen f l u o r i d e t n a t j.s produced d u r i n g r.eduction i s

removed tiy a NaF t r a p . I n s t rumentat i o n is provided t o measure the d . i :Werenti.?in. p r e B s u r e

ilci:oss t h e coluriin, t h e p r e s s u r e u t t h e t o p oJs khe col.1.m.fi, a,nd t h e salt

head above the s d t f i l t e r .

A n a n a l y s i s for water i n the system off-

gas i s Imde d u r i n g ox.ide remova:L t o determine the r a t e a t which o x i d e

i s removed, and an a n a l y s i s f o r fl.uori.de 5.n t h i s stream i s mmde d u r i n g

i;he i.ron r e d u c t i o n s t e p

t G

provi.de a cheek on t h e r a t e of r e d u c t i o n as

i n d i c a t e d by t h e a n a l y s i s o f f i l t e r e d salt samples.

P e r i o d i c examination

of t h e f i l t e r (and p ~ s s i . % l yo f t h e column p a c k i n g ) will provide informa-

t i o n on t h e p a r t i c l e s i z e , f i l t e r a b i l i t y , and d i s p o s i t i o n o f t h e i r o n .

J. R . Hightower, Jr

1-44

I,. E . McNeese

R e s u l t s of f i n a l . a n a l y s e s have been o b t a i n e d f o r Li, Be, Zr, 95Zr,

Ce, ’’‘‘Pm,

155Eb, 91Y, ”ST,

(.I

9S r , and 137Cs i n t h e 1.1 condensate

samples taken d u r i n g t h e MSRE D i s t i l l a t i o n Experiment.

These r e s u l t s

(shown i n Table 5 ) have been used t o c a l c u l a t e t h e e f f e c t i v e r e l a t i v e

v o l a t i l i t y o f each component, w i t h r e s p e c t t o LiF, d w i n g t h e course 1% of t h e experiment by methods d e s c r i b e d p r e v i o u s l y .

?url i l o r a g e t a n k - l :Dnt.r analyzeGI

(Date m a i y z e 11 -1

-2

-3 -I/

-5 -6 -7 -8 -9 -10

. 1 (Datr nnx'yaed)

3 . i 8 x 109

3.11

3.2: x 1010 L 5/2/69)

3 . 7 5 x 109

3.35 x -39

(4/25/69)

F u e l stsrage tank-? CondPnsatr samples

3.14 x lo1'

3.88 4.67 6.86

ii.-A

1i.U

8.48

12.05

7.211

9 . i6

8.15

10.00

10.09 10.48

7.05

;C.39

9.93

7.82

9.2'.

8.77 9.80

8.46

13.02 Li.23

7.66

10.04

6.83 x i o 6

1 . 2 1 x 10'

2.39 x 10' 1.97 x 10'

101

8.09

IC.53

2.89 Y 10' a 1.99 x 10

8.71

4.63 x LO8

10.L9

9.83

5.11

5.26

5.77

e.11

( 5 / 2 1 / 6 9 ) (5/23/69) (5/29/69)

3.01 x 10'

4.75

x 108

~ . g xi

(7/2i/Q)

159 :lii24/691

(>/?i/69)

(4/29/69)

(~1/10/6?1

.r.6 x i o 6 1.53 x 2.78 x 2 . 2 3 x 10' 8.85 x 106

3 . 2 0 x 107

2.16

107

3.08 107 1.98 x A 7 6.21 Y lo7 6.90 x &07 17/2/69]

6.54

105

1 . 1 8 x 106 1.44 x

lo6

1.32 x 106

6.14 1.81 x 1.i5 x 1.60 x 2.29 x 6.01 x

105

106

LO'

lo6 lo6

lo6

4.10 x 1 0'

(9130169)

.2.1 x 166

( 5 . 2 x 106

9.54 x 106 5.76

100

s2.5 x 106

8.93 x 106 e.57 loL 8.75 x 106 1 . 5 6 x 10' 2.37 x 107 3.011 x 10'

(7/8/6?1

9.u 109 6.19 x 3.33 109 3 . 5 3 x LO9 3.14 109 2.61

--09

1.66 x

i09

5.91 X 10' 4.06 x LO8 2.6;

x 10'

2 . 9 6 x 10' (:'/21/69)

7.9 10.0

11.2 12.6

13.4

0.42

1.93 p.96

3.81

4.35

13.6

4.95

13.8 13.8 13.8

6.89

13.5

5.80

6.34 7.49 7.85

81 The e f f e c t i v e r e l a t i v e v o l a t i l i t y of each component, w i t h r e s p e c t t o LiF, i s shown i n F i g s . 31-34 as a f u n c t i o n of t h e volume of c o l l e c t e d

The most s e l f - c o n s i s t e n t v a l u e s were o b t a i n e d when t h e car-

condensate.

r i e r s a l t composition i n t h e f e e d was assumed t o be 65-30-5

mole

% LiF-

BcF2-ZrP’4 r a t h e r than a s l i g h t l y d i f f e r e n t composition as i n d i c a t e d by t h e a n a l y s i s of t h e s a l t from t h e f u e l s t o r a g e t a n k .

The d i f f e r e n c e be-

tween t h e a n a l y t i c a l v a l u e s and t h e v a l u e s used i s probably due t o t h e p r e s e n c e of zirconium m e t a l i n t h e f u e l s t o r a g e t a n k .

The zirconium was

f i l t e r e d a u t when t h e s a l t was t r a n s f e r r e d t o t h e s t i l l f e e d t a n k . The e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of t h e major s a l t components 3eF

and ZrF

arid o f t h e f i s s i o n p r o d u c t 95ZrF

The e f f e c t i v e r e l a t i v e v o l a t i l i t y of Bel?

2’

a r e shown i n F i g . 31.

which was e s s e n t i a l l y c o n s t a n t

d u r i n g t h e r u n , had an average v a l u e of 3.8.

This value agrees favorably

w i t h t h e v a l u e of 3.9 r e p o r t e d by Smith, F e r r i s , and T h o ~ n p s o n ,b~u~t i s lower t h a n t h e v a l u e of

4.7 measured by Nightower and McPJeese.l4

Slight

i n a c c u r a c i e s i n c a l c u l a t i o n s ( e s p e c i a l l y t h e material b a l a n c e c a l c u l a t i o n s d e s c r i b e d e a r l i e r ) and a n a l y s e s p r o b a b l y account f o r t h e s e d i f f e r e n c e s . Tihe e f f e c t i v e r e l a t i v e v o l a t i l i t i e s o f f i s s i o n product 95Zrl?

n z t u r a l ZrF

4 are

4 and of

‘hen t h e a n a l y s i s of t h e f u e l s t o r a g e tank

i n agreement.

s s l t was used i n t h e r e l a t i v e v o l a t i l i t y c a l c u l a t i o n , t h e r e s u l t i n g r e l a t i v e v o l a t i l i t i e s of t h e n a t u r a l ZrF

va.lues f o r 95ZrFb. v a l u e near

were about a f a c t o r o f 2 lower t h a n the

F i g u r e 31 shows t h a t a ZrF4-LiF d e c r e a s e d from a n i n t i a l

a t t h e s t a r t of t h e Tun t o about 1 a t t h e end o f t h e r u n .

These v a l u e s b r a c k e t t h e v a l u e o f 2.2 measured by Smith and co-workers i n

s a l t m i x t u r e s having a ZrFk c o n c e n t r a t i o n about 2% of t h a t used i n our sy stem.

The e f f e c t i v e r e l a t i v e v o l a t i l i t i e s f o r t h e l a n t h a n i d e f i s s i o n p r o d u c t a ,

144CeI:

3’

147h F 3 ,

and 155EuF2, a r e shown i n F i g . 32.

t i v e y e l a t i v e v o l a t i l i t y of 144CeF

The -value of t h e e f f e c -

i n c r e a s e d s h a r p l y froin

6.1 x

-4

at t h e

t i m e of t h e f i r s t sample t o about 1 . 0 x I O w 2 , where it remained f o r n e a r l y all t h e subsequent samples.

x lom2 by a f a c t o r o f 3.

The fifth s a m p l e , however, w a s lower t h a n 1 . 0

The l o w i n i t i a l v a l u e was 1 . 5 to 3.4 times t h e

va.1-ue measured i n a n e q u i l i b r i u m still;’*

t h e h i g h e r v a l u e s were 24 t o

t i m e s t h e v a l u e measured i n t h e e q u i l i b r i u m s t i l l .

10-

0RNL.- DWG 70- 4 5 i 5 1

10-3

a >-'

z! I-

-I

> W

s J

10-2

10-4

10-0

0.86 x 1 2

I 3

I 4

0 <1.4 x

ls5Ei

10-4

I 5

I 7

LITERS CONDENSATE C O L L E C T E D

Fi.g. 3 2 . E f f e c t i v e R e l a t i v e Volatilities of 155E:u'i.'2 in the MSRE D i s t;il.lat, i.oLi E x p e i - i r ~ ~ c n t .

144CeF3, 147EmT3, and

ORNL DWG 70-4514

A"%7

LITERS CONDENSATE COLLECTED

Fig. 33. E f f P c t i v e R e l a t i v e Volatilities of 91Yj'3 snri 9Osil2 in t h z I G R E Distillation Experiment.

0.l

LITERS CONDENSATE COLLECTED

Pig. 31.4. E r f c c t i v e F?elative V o l a - t i l i . t y of 137CsF in YSI?E D i s t i l l a t i o n Experiment, Showing Effect of Variation of A s s u m e d Feed Concentration.

86 The e f f e c t i v e r e l a b i v e v o l a t i . l i t y f o r 147PmF f e e d c o n c e n t r a t i o n , which i s bel.ieved t o be

i s based on a computed

more a c c u r a t e v a l u e t h a n

t h e measu.red f e e d c o n c e n t r a t i o n ( s i n c e measured c o n c e n t r a t i o n s of o t h e r l a n t h a n i d e f i s s i o n p r o d u c t s were i n good agreement w i t h computed concent r a t i o n s and s i n c e t h e measured c o n c e n t r a t i o n i s i n d o u b t ) . A s i n t h e 1411. eF t h e r e l a t i v e v o l a t i l i t y of 14''hF,. a t t h e t i m e o f t h e case of

t h a n 7.8 x

f i r s t sample w a s low--less

3.4 x

low3 for

t h e o t h e r samples.

it r o s e s h a r p l y t o about

r e l a t i v e v o l a t i l i t y of t h e f i f t h sample w a s low. measured v a l u e s of t h e r e l a t i v e v o l a t i l i t y o f PmF

There were no p r e v i o u s l y

w i t h which t o compare

It i s f n t e r e s t i n g t o n o t e t h a t when t h e e f f e c t i v e r e l a - -

these results.

t i v e v o l a t i l i t y of llr7F'mF t r a t i o n of

1 4 4 eF 3' t h e

Again, as i n t h e c a s e of

1.47

was c a l c u l a t e d based on t h e measured concen-

Pm i n the f u e l s t o r a g e t a n k ( i n s t e a d of a c a l c u l a t e d con-

c e n t r a t i o n ) , t h e r e l a t i v e v o l a t i l i t y v a l u e f o r each sample except t h e f i r s t near1.y c o i n c i d e d w i t h t h e r e s p e c t i v e v a l u e f o r

1 4 4CeF

The v a r i a t i o n of t h e r e l a t i v e v o l a t i l i t y of 155EuF d u r i n g t h e Fun

1 4 4CeF, and 147PmF,. The val-ue f o r t h e f i r s t sample w a s low ( l e s s t h a n 1 . 5 x 1 0-5 ) ' b u t t h e v a l u e s

c l o s e l y p a r a l l e l e d t h e v a r i a t i o n s far

f o r a l l o t h e r samples except for t h e f i f t h sample were a g r e a t d e a l

-4

h i g h e r ( a b o u t 2.2 x 1 0 a f a c t o r of 2 . 6 .

)

The v a l u e f o r t h e f i f t h sample w a s lower by

These c a l c u l a t e d e f f e c i f v e r e l a t f v e v o l a t i l i t i e s (which

were based on a computed f e e d c o n c e n t r a t i o n of t h e v a l u e of l.1 x lo-'

were lower t h a n

measured i n r e c i r c u l a t i n g e q u i l i b r i u u i s t i l l s .

However, t h e v a l u e s f o r lS5Eu i n t h e condensate are s u s p e c t e d o f b e i n g i n a c c u r a t e s i n c e d i f f i c u l t y w a s experienced i n t h e a n a l y s e s ; t h e r e f o r e ,

a l l 155Eu a n a l y s e s f o r t h e condensate smples were r e p o r t e d as approximate v a l u e s ( s e e Table

5).

On t h e o t h e r hand, it i s s i g n i f i c a n t t h a t

t h e varia-Lion i n t h e r e l a t i v e v o l a t i I . i t y o f 155Eu d u r i n g t h e r u n c l o s e l y

p a r a l l e l e d t h e r e l a t i v e v o l a t i l i t i e s of "'"CeF seen l a t e r , "YF

and "SrF2).

and 147h1F

( a n d , as

F i g u r e 33 shows t h e e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of "YF, The e f f e c t i v e r e l a t i v e v o l a t i l i t y of "YF

aria -3 average v a l u e

had ax1 3 -2 d-uring t h e r u n o f 1.14 x 1.0 , about 410 -timest h e v a l u e measured i n "SrF

recirculating equilibrium s t i l l s .

The v a r i a t i o n of t h e 'lYF

relative

v o l a t i l i t y d u r i n g t h e r u n resembled v a r i a t i o n s i n t h e r e l a t i v e v o l a t i l i -

t i e s of t h e l a n t h a n i d e s ; t h e low v a l u e f o r t h e f i f t h s m p l e w a s t h e most n o t i c e a b l e similari t,y. During t h e r u n , t h e e f f e c t i v e r e l a t i v e v o l a t i l i t y of 90SrFg (based on t h e measured c o n c e n t r a t i o n i n t h e f e e d ) had an average v a l u e of

h.1

x lom3, which i s about 84 times Lhe v a l u e measured i n r e c i r c u l a t i n g

Although n o t shown i n F i g . 33, t h e average v a l u e

equilibrium s t i l l s .

(based on a computed c o n c e n t r a t i o n 2 i n t h e f e e d ) was 0.193, about 3900 t i m e s t h e v a l u e measured i n e q u i l i b -

of t h e r e l a t i v e v o l a t i l i t y of 89SrF

rium s t i l l s ; and t h e r a t i o of t h e 8gSr a c t i v i t y t o t h e 90Sr a c t i v i t y i n t h e condensate samples, which should have been about 0.002 f o r each sample, v a r i e d from 0.22 t o g r e a t e r t h a n LO. The c o n c e n t r a t i o n o f 137Cs i n t h e f e e d s a l t w a s n o t measured; i n s t e a d ,

c a l c u l a t i o n of t h e e f f e c t i v e r e l a t i v e v o l a t i l i t y w a s based on an e s t i mated f e e d c o n c e n t r a t i o n .

Since

has a f a i r l y long-lived gaseous

pyecursor (137Xe, h a l f - l i f e of 3.9 m i n ) , i t s a c t u a l c o n c e n t r a t i o n i n t h e s a l t w i l l be lower t h a n t h a t c a l c u l a t e d i f we assume t h a t a l l t h e pre-

c u r s o r s remained i n t h e s a l t .

A l s o , because t h e a c t u a l r e l a t i v e vola-

t i l i t y of CsF i s f a i r l y h i g h , t h e r e s u l t s of t h e c a l c u l a t i o n s of t h e e f f e c t i v e r e l a t i v e v o l a t i l i t y a r e s e n s i t i v e t o t h e assumed f e e d concent r a t i o n of 137Cs.

F i g u r e 34 shows c a l c u l a t e d r e l a t i v e v o l a t i l i t i e s of

137CsF for two assumed f e e d c o n c e n t r a t i o n s * The p o i n t s around t h e lower curve r e s u l t from t h e f e e d c o n c e n t r a t i o n t h a t would a r i s e as a conse-

qlJence of a l l p r e c u r s o r s s t a y i n g i n t h e s a l t d u r i n g MSRE o p e r a t i o n and

r e p r e s e n t lower l i m i t s f o r t h e r e l a t i v e v o l a t i l i t y ; t h e p o i n t s around t h e upper l i n e r e s u l t from a f e e d c o n c e n t r a t i o n j u s t h i g h enough t o prevent t h e computed c o n c e n t r a t i o n of "'Cs

i n t h e still p o t l i q u i d from

falling t o z e r o , and. r e p r e s e n t upper l i m i t s f o r t h e e f f e c t i v e r e l a t i v e

v o l a t i l i t y of 137CsE'.

The h i g h e s t e f f e c t i v e r e l a t i v e v o l a t i l i t y of L37CsF

seen i n t h e s e c a l c u l a t i o n s w a s o n l y about 20% of t h e v a l u e measured i n

LiF-BeF ZrF

m i x t u r e s by Smith and eo-workers.

A s seen from t h e previous r e s u l t s , a l l components except BeF

and

had e f f e c t i v e r e l a t i v e v o l a t i - l i t i e s t h a t d i f f e r e d s i g n i f i c a n t l y

( i n some c a s e s , d r a s t i c a l l y ) from v a l u e s p r e d i c t e d from work w i t h equilibrium systems.

P o s s i b l e explana,tions f o r t h e s e d i s c r e p a n c i e s are

being examined.

13. RECOVEIiY OF 7L i FTOM 7Li--BIS~TH--~RE-EARTH SOLUTI ON S BY D I STILLATI ON

J. R . Hightower, 3r.

L . E. McNeese

Removal o f d i v a l e n t l a n t h a n i d e s from t h e L i C l s t r e a m i n t h e metalt r a n s f e r p r o c e s s produces a bismuth stream t h a t contai.ns l a n t h a n i d e s , a l o n g w.i.th a h i g h c o n c e n t r a t i o n of 7L5 ( o n t h e o r d e r of 10 to $0 a t .

%).

Because of t h e h i g h c o s t of 7L i , i t s r e c o v e r y may be economi.ca1.

The low vapor p r e s s u r e s o f t h e l a n t h a n i d e m e t a l s , as compa.red wi-LIi t h o s e o f L i and B i , s u g g e s t t h a t d i s % i l l a t i o n might b e used e f f e c t i v e l y t o recover

L i and Hi.

However, s i n c e L i and Ui form a n i n t e r m e t a l l i c

compound ( L i R i ) having a h i g h m e l t i n g p o i n t (1145'C),

t h e Li concen-

t r a t i o n i n t h e s t i l l c o u l d become high enough i n t h e c o u r s e o f d i s t i l l a t i o n t h a t s o l i d L i Bi would. b e formed i n t h e s t i l l p o t .

Calcu-

l a t e d r e s u l t s t h a t i n d i c a t e t h e expected perfosmance of a one-stage continuous e q u i l i b r i u m s t i l l are d i s c u s s e d i n t h i s s e c t t o n .

The

f r a c t i o n a l r e c o v e r y of l i t h i u m i s c a l c u l a t e d f o r a s e t of conditrions that, allow a r e a s o n a b l y h i g h r e c o v e r y .

The e x t e n t of s e p a r a t i o n of

t h e r e c o v e r e d l i t h i u m from t h e l a n t h a n i d e s was assumed to be adequate

and w a s not c o n s i d e r e d . 13.1

Ma,thematical A n a l y s i s

Ma-Lerial Balance b o u n d a Continuous S t i l l .

- Consider

a single-

s t a g e e q u i l i b r i u m s t i l l . t o which a bismuth stream c o n t a i n i n g l i t h i u m

i s fed ( t h e l a n t h a n i d e f i s s i o n p r o d u c t s a r e assimed t o b e n o n v o l a t i l e

and w i l l be n e g l e c t e d ) and from which a n overhead stream and a, bottoms stream a r e drawn ( e a c h stream c o n t a i n s bismu.th and 3.ithiu.m). A steady-

s t a t e m a t e r i a l b a l a n c e around t h e s t i l l y i e l d s t h e f o l l o w i n g e q u a t i o n :

where

(1 - f)X

4 fY

(441

Li i n t h e feed stream,

Z = atom f r a c t i o n o f

X = atom f r a c t i o n of L i i.n t h e s t i l l bottoms stream,

Y = atom f r a c t i o n of L i i n t h e overhead stream from t h e s t i l l , f = f r a c t i o n of t h e f e e d stream v a p o r i z e d i n t h e s t i l l , moles

vapor p e r mole of l i q u i d f e d . The vapor phase and t h e l i q u i d phase l e a v i n g t h e s t i l l are assumed t o be i n e q . u i l i b r i m ; t h e c o n c e n t r a t i o n s of t h e s e phases a r e r e l a t e d t h r o u g h

t h e relatirre v o l a t i l i t y of l i t h i u m w i t h r e s p e c t t o bismuth, which i s defined as:

aL i - B i

Y(1 X(l

- x> - Y) '

(45)

where a

i s a f u n c t i o n of system t e m p e r a t u r e , p r e s s u r e , and compo-

sition.

(The e v a l u a t i o n of aLi -Bi w i l l b e d i s c u s s e d i n a Is-ter s e c t i o n . )

Li-Bi

S u b s t i t u t i o n of Eq.

( 4 5 ) i n t o Eq. ( 4 4 ) y i e l d s t h e f o l l o w i n g e q u a t i o n ,

wliich r e l a t e s t h e s t i l l - p o t

composition t o t h e f r a c t i o n of material d i s -

tilled

Because a

Li-Bi

depends on X , t h i s e q u a t i o n must be solved i t e r a t i v e l y .

The r e l a t i . v e v o l a t i l i t y of l i t h i u m w i t h r e s p e c t t o bismuth i s r e l a t e d

t o t h e vapor p r e s s u r e s o f t h e two components through t h e r e l a t i o n

where

'Li

and y

are t h e l i q u i d - p h a s e a c t i v i t y c o e f f i c i e n t s o f L i and Bi, r e s p e c t i v e l y , a t t h e t e m p e r a t u r e , p r e s s u r e , and composition of t h e l i q u i d i n t h e s t i l l ;

PLi and PBi a r e t h e vapor p r e s s u r e s of L i and B i , r e s p e c t i v e l y ,

a t t h e t e m p e r a t u r e of t h e s t i l l .

90 Eva,l.uation of .the a c t i v i t y c o e f f i c i e n t s f o r u s e i n Eq.

(1.~7)i s

discussed i n t h e following s e c t i o n .

E v a l u a t i o n of A c t i v i t y C o e f f i c i e n t s for t h e L i - B i System. - T h e a c t i v i t y c o e f f i c i e n t f o r l i t h i u m i n L i - B i s o l u t i o n s h a s been measured.1 5 and i s expressed by t h e f o l l o w i n g e q u a t i o n :

where 2 A(T) = 9397 I- 18.16~- 0.010g'I' cal/mole, 2 R(T) = 7103 - 19.442' I- 0.0068~~c a l / m o l e , R = g a s c o n s t a n t = 1.987 c n l sole-1 OK-l Y

T = absolute temperature,

OK.

T h i s e q u a t i o n i s v a l i d f o r t h e composition r a n g e 0.05 < X < 0.60, i n t h e

t e m p e r a t u r e range

775OK 2 T 2 l l O O 째 K

and a t a p r e s s u r e of 1. atm.

The a c t i v i t y c o e f f i c i e n t of bikmuth i s o b t a i n e d from Eq.

(48) through

t h e Gibbs-Duhem eqiiatj-on f o r a b i n a r y system a t constarit t e m p e r a t u r e ,

i n t h e f o l l o w i n g form :

. ClP

ax *

__.

where v = volume of one mole o f L i - B i a l l o y ,

V = molar 2,i - = molar

vol.ume of pure L i , volume of p u r e B i ,

P = t o t a l pressure of system. When E q . 0 + 9 ) i s i n t e g r a t e d w i t h r e s p e c t t o X from X = 0 t o t h e d e s i r e d v a l u e , t l LC- f o l l o w i n g equat i on i s o h t a i ned :

X X

= -

1-x

P a t X = X In y

Li dx

- xvLi - (1 - X)YBJ

RT (1- X )

P a t X = O

The l a s t term w i l l h e neglected s i n c e i t s v a l u e i s less t h a n

6 x

-4 ,

which i s n e g l i g i b l e as compared w i t h t h e v a l u e of t h e n e x t - t o - l a s t (i.e., > 0.1).

.(50)

term

Thus, t h e following r e l a t i o n , v a l i d f o r low pressures,

w i l l be used t o e v a l u a t e y

Bi*

X l n yB i = - [

The q u a n t i t y

3 I n YLi

3 I n y-

(1 - XI

(51)

can be e v a l u a t e d from E q . ( 4 8 ) ; s u b s t i t u t i n g

t h i s q u a n t i t y i n t o Eq. ( 5 1 ) and i n t e g r a t i n g t h e r e s u l t i n g e x p r e s s i o n results in:

Equations ( 5 2 ) and (48) can be combined with Eq. ( 4 7 ) t o g i v e t h e following r e l a t i o n f o r t h e r e l a t i v e v o l a t i l i t y o f l i t h i u m , w i t h respect t o bismuth:

The vapor p r e s s u r e of l i t h i u m i s given by t h e following e q u a t i o n , which

was d e r i v e d from data given i n r e f .

17:

1n P = Ei

where

16746 16.81.3- T

(54)

PL i = vapor p r e s s u r e of L i , mm H g , T

OK.

= absolute temperature,

The e q u a t i o n f o r t h e vapor p r e s s u r e of bismuth used i n t h e s e c a l c u l a t i o n s

was o b t a i n e d from r e f . 18 and i s a s follows:

loglo PBi = 7.6327

where

- 9 1T5 0 . 3

(55)

= vapor p r e s s u r e of Bi, mm Hg,

= absolute temperature,

OK.

Method for S o l--v i N Equations. - The method f o r s o l v i n g t h e e q u a t i o n

f o r t h e s t i l l - p o t composition (assumed t o be t h e same as t h e s t i l l bottom s t r e a m ) c o n s i s t e d of t h e f o l l o w i n g s t e p s : 1. A s t i l l - p o t t e m p e r a t u r e im,s chosen; t h i s a,llowed t h e

e v a l u a t i o n of t h e f o l l o w i n g terms i n E q . ( 5 3 ) :

PQi, A(T)/XT, B(T)/RT2.

Li,

The above terms were s u b s t i t u t e d i n t o E q . (53) t o g i v e a n e x p r e s s i o n for o n l y on X.

Li-Ri

which was dependent

was s u b s t i t u t e d i n t o Eq. ( 4 6 ) .

The e x p r e s s i o n f o r a

Equation

Once t h e stj.l-l-pot composition was determined, t h e

Li-Bi

(46 ) was solved u s i n g t h e New-ton-Naphson algo-

r i t ? ~ n 'f~o r a range o f v a l u e s o f f and Z .

l i q u i d u s temperature f o r t h i s composition c o u l d be determined from t h e L i - B i phase diagram. * O

The

f r a c t i o n a l r e c o v e r y of l i t h i u m i n t h e overhead stream w a s c a l c u l a t e d from t h e f o l l o w i n g e q u a t i o n :

R = 1 - (1- f ) 7x, ,

93 where R is the number of moles of lithium in the overhead stream per mole of lithium in the feed stream.

13.2 Calculated Results Still-pot compositions, liquid temperatures, and fractional lithium

recoveries were calculated for still-pot temperatures of 800째C and 9 O O 0 C , feed compositions of

0,7O to 0 . 9 9 .

5, 10, and 20 at. % lithium, and values of f from

Figure 35 shows the liquicius temperature of the still-pot

liquid for an operating temperature of 8oo0c, the three feed composi-

tions, and vaporizatioG of up to 95% of the incoming Bi-Li stream. a feed composition of 10 or 20 at.

would be less than

For

lithium, the maximum lithium recovery

36%. For a feed composition of 5 Et. % lithium, a

lithium recovery of greater than 50% could be achieved before solid Li Bi 3 would be formed in the still pot. Figure

36 shows the liquidus temperature of the still-pot liquid

for an operating temperature of gOO째C, the three feed compositions, and

vaporization of up to 95% of the incoming Bi-Li stream.

For a given

fraction vaporized and a given f e e d composition, distillation at 900째C

produces a still-pot composition with a slightly lower liquidus tempera-

ture

The lower liquidus temperature, combined with the higher still-

pot temperature, allows higher recovery of lithium than distillation at 8130Oc does. With a feed composition of 10 at. % lithium, a maximum lithium recovery of

66% can

be obtained. With a feed composition of

at. % lithium, very high lithium recoveries can be achieved, as shown in Fig. 37.

About 90% of the lithium could be recovered by vaporizing

99% of the incoming Bi-Li stream; the liquidus temperature of the stillp a t material in this case would be only about 630'~. The following difficulties with recovery of 7Li from bismuth by

distillation became apparent as a result of these calculations:

(1) It will be difficult to find materials of construction that can withstand

the high temperatures necessary to achieve high lithium recoveries.

(2) The vapor pressures of the Bi-Li mixtures are low even at temperatures around 900째C (for example, for recovery of 90% of the lithium, a

O R N L - Q W G - 70-6249

0.85 I, craction Distilled

Fig. 35. L i q u i d u s T e n p e r a t J r e o f S ' , i l l - P o t Yaterik; ir, Cocticuous ~ i - S~t l li; Operatirig a t 8 0 0 O c . E f f e c t s of feec composition and f r a c t i o n o f feed v a p o r i z e d .

\ c I

oci m

0 0

I!G

0 0 d

0 0

vspor p r e s s u r e of o n l y 0 . 2 t o 0 . 3 mm Hg w a s c a l c u l a t e d f o r t h e s t i l l pot m a t e r i a l ) ; t h e low vapor p r e s s u r e s would r e s u l t i n low v a p o r i z a t i o n fluxes.

Consequently, l a r g e v a p o r i z a t i o n areas would be needed.

(3)

Because t h e l i t h i u m c o n c e n t r a t i o n i n t h e feed must b e low t o p r e v e n t t h e f o r m a t i o n of L i B i i n t h e s t i l l p o t , a d d i t i o n a l p r o c e s s i n g c o m p l e x i t i e s

3 must be added t o d i l u t e t h e B i - L i stream coming from t h e e x t r a c t i o n column.

Although t h e s e d i f f i c u l t i e s are n o t insurmountable, t h e y pro-

v i d e i n c e n t i v e t o s e a r c h f o r a l t e r n a t i v e methods f o r r e c o v e r i n g t h e 'Li.

14. PREVICM'TION OF AXIAL DISPERSION IN J . S. Watson

PACKED COLUMNS

L . E. McMeese

The use o f packed column c o n t a c t o r s i n MSBR f u e l p r o c e s s i n g systems

i s being considered.

A s shown previously,21 a x i a l d i s p e r s i o n c a n

s i g n i f i c a n t l y r e d u c e t h e performance o f t h i s t y p e o f c o n t a c t o r under o p e r a t i n g c o n d i t i o n s of i n t e r e s t .

A s p a r t of our c o n t a c t o r development

program, we are e v a l u a t i n g m o d i f i c a t i o n s t o packed columns t h a t w i l l

r e d u c e t h e e f f e c t of a x i a l d i s p e r s i o n t o a n a c c e p t a b l e l e v e l .

The pro-

posed m o d i f i c a t i o n s c o n s i s t of i n s e r t i n g d e v i c e s a t p o i n t s a l o n g t h e column t o r e d u c e d i s p e r s i o n a c r o s s t h e column a t t h e s e p o i n t s .

If t h e

devi-ces a r e s e p a r a t e d by a column l e n g t h e q u i v a l e n t t o one t h e o r e t i c a l s t a g e ( a n e x t e n t of s e p a r a t i o n t h a t c a n be achieved even i f t h e f l u i d s between t h e d e v i c e s a r e c o m p l e t e l y m i x e d ) , t h e s t a g e e f f i c i e n c y of t h e column segment w i l l be g r e a t e r t h a n 75% if 15% o r l e s s of t h e s a l t flowing t h r o u g h the segment i s r e c y c l e d t o t h e p r e v i o u s segment. The t y p e of d e v i c e under i n v e s t i g a t i o n i s shown i n F i g . 38.

The

metal stream f l o w s down a n a n n u l a r s e c t i o n i n t h e upper p o r t i o n of t h e

d e v i c e i n t o t h e p o r t i o n t h a t i s e f f e c t i v e l y a n i n v e r t e d a n n u l a r bubble cap.

The accumulated m e t a l forms a seal and f o r c e s t h e l e s s - d e n s e phase

t o flow upward t h r o u g h r e s t r i c t i o n s i n a sieve p l a t e .

A significantly

h i g h e r s a l t v e l o c i t y i s o b t a i n e d t h r o u g h t h e r e s t r i c t i o n s , and a cons i d e r a b l y d i m i n i s h e d r e c y c l e o f s a l t should o c c u r a c r o s s t h e d e v i c e . We have t e s t e d two d e v i c e s of t h i s t y p e , u s i n g mercury and water t o

2â&#x20AC;&#x2122;I.g.

38. Schematic Diagram of an

A x l a 1 DisIJersion P r e v c n t e r .

s i m u l a t e bismuth and s a l t .

One o r more d i s p e r s i o n p r e v e n t e r s were

i n s e r t e d near t h e middle of a 2-in.-diam 3/8-in.

c o l m t h a t w a s packed w i t h

Easchig r i n g s .

The e x p e r i m e n t a l t e c h n i q u e c o n s i s t e d of e s t a b l i s h i n g a c o u n t e r c u r r e n t flow of mercury and water t h r o u g h t h e column and i n j e c t i n g a s t e a d y f l o w of t r a c e r s o l u t i o n ( c u p r i c n i t r a t e ) a t a p o i n t near t h e t o p of t h e column,

The t r a c e r c o n c e n t r a t i o n w a s determined a t s e v e r a l

p o i n t s along t h e column.

When t h e l o g a r i t h m of t h e t r a c e r c o n c e n t r a t i o n

w a s p l o t t e d as a f i n e t i o n o f d i s t a n c e a l o n g t h e column, a d i s c o n t i n u i t y i n t r a c e r c o n c e n t r a t i o n w a s observed a t t h e p r e v e n t e r l o c a t i o n , as sho%m i n F i g . 39.

The r a t i o of t h e c o n c e n t r a t i o n s a t t h e d i s c o n t i n u i t y i s a

measure o f t h e f r a c t i o n of t h e water t h a t w a s r e c y c l e d through t h e preventer. The f r a c t i o n o f t h e water r e c y c l e d t h r o u g h a p r e v e n t e r apFears t o depend mainly on t h e water f l o w r a t e p e r sieve opening and t h e diameter oP t h e s i e v e opening.

No dependence on t h e mercury flow rate was e v i -

d e n t , a l t h o u g h t h e s m a l l number o f d a t a g o i n t s and t h e u s u a l d a t a s c a t t e r make t h i s c o n c l u s i o n t e n t a t i v e .

The e f f e c t of metal Tlow r a t e i s

expected t o become q u i t e l a r g e , however, f o r m e t a l flow rates s u f f i c i e n t l y h i g h t o p r e v e n t complete m e t a l c o a l e s c e n c e i n t h e downcomer. The f i r s t p r e v e n t e r t o undergo t e s t i n g c o n s i s t e d of a 1/2-in.-deep bubble c a p and a l / b - i n . - t h i c k holes.

s i e v e p l a t e c o n t a i n i n g f o u r 3/32-ine-diam

A s shown i n F i g . 4 0 , o n l y t h r e e data p o i n t s were o b t a i n e d w i t h

t h i s d e v i c e ; however, t h e f r a c t i o n of water t h a t i s r e c y c l e d i s observed t o d e c r e a s e w i t h i n c r e a s i n g water f l o w r a t e .

Less t h a n 15% of t h e water

was r e c y c l e d f o r a water flow rate g r e a t e r t h a n 90 ml/min ( 2 2 m l p e r minute p e r h o l e ) . 1/21

in.

The openings were t h e n d r i l l e d o u t to a d i a m e t e r o f

A s shown i n F i g . 40, s i m i l a r r e s u l t s were o b t a i n e d , a l t h o u g h

tlie f r a c t i o n of water r e c y c l e d d i d not r e a c h a n a c c e p t a b l y low l e v e l i n

any of t h e s e experiments.

By e x t r a p o l a t i n g t h e c u r v e , one c a n e s t i m a t e

that t h e f r a c t i o n of w a t e r r e c y c l e d would be l e s s than 15% a t a water

f l o w r a t e between 150 and 200 ml/min ( a p p r o x i m a t e l y 50 r n l p e r minute p e r

hole)

100

1.6(

0. 0.

6 .a 0.

laJ

w La. w

e a 6)

0.2

6.1

Fig. 39. C o n c e n t r a t i o n P r o f i l e Using a Backflow P r e v e n t e r with a S i n g l e 3 / 8 - i n . Sieve Opening. Mercury flow r a t e , LOO ml/min; w a t e r f l o w r a t e , 115 ml/min.

101

1.0

1 -

O R N L D W I 70-11045 I

Preventsr

A 0

Number of Holes

Hole Diam, (in)

3/32

0.6

.-cx .-

a 0 0

m c

0 .-c 0

b-1

60 80 W o t r r R o t s , mliâ&#x20AC;&#x2122;min

100

I20

140

ig. 1.10. F r a c t i o n Backmixing Across Two Axial I)ispersj.on P r e v e n t e r s Having Various O r i f i c e Diameters. I

102 A second d i s p e r s i o n p r e v e n t e r , which had a 2-in.-deep

and only a s i n g l e 1/16-in.-diam

tested.

bubble cap

opening i n t h e s i e v e p l a t e , w a s a l s o

No r e c y c l e could be d e t e c t e d a t t h e lowest measurable water

r a t e ( 2 3 . 5 ml/min).

T'ne diameter of t h e opening was i n c r e a s e d t o

i n . , and a g a i n no r e c y c l e w a s d e t e c t e d . increased t o

l/j+

1./8

When t h e o r i f i c e diarnet,er w a s

i n . , t h e r e s u l t s shown i n F i g . 40 were o b t a i n e d .

The

f r a c t i o n of water r e c y c l e d is less t h a n S.s% i f t h e water flow r a t e is g r e a t e r t h a n 50 ml/min.

Note t h a t t h i s v a l u e a g r e e s w i t h t h e r e s u l t s

e s t j m a t e d by e x t r a p o l a t i n g r e s u l t s from t h e f i r s t p r e v e n t e r w i t h f o u r 1/4-in.

holes.

The o r i f i c e diameter was f u r t h e r i n c r e a s e d t o 3/8 i n .

t o o b t a i n t h e r e s u l t s shown i n F i g . 40.

The f r a c t i o n o r water recycl-ed

w a s i n c r e a s e d c o n s i d e r a b l y by t h i s change i.n d i a m e t e r ; a g a i n , however, t h e f r a c t i o n of water r e c y c l e d could be reduced t o any d e s i r e d v a . l . 1 ~ a t s u f f i c i e n t l y h i g h w a t e r flow r a t e s . An u n d e s i r a b l e f e a t u r e of d i s p e r s i o n p r e v e i i t e r s o f t h e t y p e d i s cussed above i.s t h a t t h e column c a p a c i t y o r f l o o d i n g r a t e i s reduced. T h i s i s t o b e expected, and i t i s u n l i k e l y t h a t a d e v i c e which w i l l . reduce t h e column c a p a c i t y by l e s s t h a n 50% w i l l b e develope&.

The

d e v i c e s t e s t e d have o p e r a t e d s a t i s f a c t o r i l y w i t h mercury flow r a t e s as

h i g h as

15% of t h e f l o o d i n g r a t e f o r a column packed w i t h 3/8-i11.

Raschig r i n g s .

15. HYDRODYNAMICS OF PACKED COLUMN OPERATION WITH HIGH-DENSITY FLUID8

Watson

1,. E . McNeese

The hydrodynamics of packed colwnn o p e r a t i o n w i t h flu.ids having h i g h d e u s i - t i e s and a l a r g e d e n s i t y d i f f e r e n c e i s b e i n g s t u d i e d i n o r d e r t o e v a l u a t e and d e s i g n countercurrent contactors f o r use in MSBR processing systems based on r e d u c t i v e e x t r a c t i o n .

Mercury and water a r e bei-ng used

t o sirriulate bismuth and molten salt i n t h e s e s t l i l i e s ,

ments,22 c a r r i - e d o u t w i t h 1 / 8 - i n . and 1/4-i.n.

3/16-i.n.

Earlier experi-

s o l i d c y l i n d e r s and w i t h

and 1 / 4 - i n . Raschig r i n g s i n a 1-in.-ID

column,demonstrated

t h a t a t r a n s i t i o n i n mode o f f l o w of t h e d i s p e r s e d phase o c c u r s brbween

1-03

t h e packing s i z e s of 3/16 i n . and 1/4 i n .

The t r a n s i t i o n appeared t o

shape ( s o l i d c y l i n d e r s o r Raschig r i n g s ) .

With t h e l a r g e r packing, t h e

be a f u n c t i o n o f t h e packing s i z e o n l y and w a s n o t r e l a t e d t o packing mercury w a s d i s p e r s e d i n t o s m a l l d r o p l e t s , which produced a l a r g e i n t e r With t h e smaller packing, t h e mercury flowed down t h e column

f a c i a l area.

i n continuous c h a n n e l s and r e s u l t e d i n a much s m a l l e r i n t e r f a c i a l area.

i?l l a r g e i n t e r f a c i a l area (and hence l a r g e packing) i s d e s i r e d i n

o r d e r t o o b t a i n h i g h rates o f mass t r a n s f e r between t h e s a l t and metal phases-. S i n c e o n l y one packing d i a m e t e r above t h e c r i t i c a l s i z e had

been s t u d i e d , :t was c o n s i d e r e d d e s i r a b l e t o s t u d y s e v e r a l larger packing

materials.

T h i s r e q u i r e d two m o d i f i c a t i o n s t o t h e experimental system:

(I) i n s t a l l a t i o n o f a column l a r g e r t h a n t h e l-in,--diam u n i t used

p r e v i o u s l y , and ( 2 ) i n s t a l l a t i o n of a mercury pump having a h i g h e r pimping c a p a c i t y t h a n t h a t used p r e v i o u s l y .

A 2-in.-ID

having a l e n g t h of 24 i n . w a s c o n s t r u c t e d , and a installed.

* Lapp

L u c i t e column CPS-3 pump w a s

The system was used by a group of MIT P r a c t i c e School

s t u d e n t s 2 3 f o r measuring f l o o d i n g r a t e s , dispersed-phase holdup, and pressure drop with 1/4-in. rings.

s o l i d c y l i n d e r s and w i t h 3/8-in0 Raschig

We l a t e r o b t a i n e d d a t a w i t h 1 / 2 - i n . Raschig r i n g s .

Results of

t h e s e s t u d i e s and development of a r e l a t i o n for p r e d i c t i n g packed

column performance d u r i n g c o u n t e r c u r r e n t I"1.o~of molten s a l t and bismuth

are d i s c u s s e d i n t h e remainder of t h i s s e c t i o n .

1 5 .I Experimental Technique and R e s u l t s The e x p e r i m e n t a l t e c h n i q u e i s t h e same as t h a t used p r e v i o u s l y darFng s t u d i e s w i t h t h e 1 - i n . - d i m

column.

P r e s s u r e drop t h r o u g h t h e

packed column w a s determined from displacement o f t h e mercury-water i n t e r f a c e a t t h e bottom of t h e column.

Dispersed-phase holdup w a s

measured by s i m u l t a n e o u s l y c l o s i n g t w o b a l l v a l v e s , t h e r e b y i s o l a t i n g a s e c t i o n o f t h e column and a l l o w i n g d e t e r m i n a t i o n of t h e t r a p p e d mercury volume

Lapp P r o c e s s Eqiaipment, I n t e r p a c e Corp., North S t

:L4482.

e ,

Le Roy, New York

Experimental d a t a showing t h e v a r t a t i o n of column p r e s s u r e d r o p w i t h continuous-phase (water) s u p e r f i c i a l v e l o c i t y f o r s e v e r a l d i s p e r s e d phase s u p e r f i c i a l v e l o c i t i e s a r e shown i n F i g s . s o l i d c y l i n d e r s and 3/8-i.n.

41. and

8aschi.g r i n g s r e s p e c t i v e l y .

42 f o r 1./4-in. Data on t h e

v a r i a t i o n of dispersed-phase holdup w i t h continuous-phase s u p e r f i c i a l v e l o c i t y f o r s e v e r a l dispersed-phase v e b o c i t i e s are shown in F i g s . 143-

1-15 f o r t h r e e packing inaterials studied..

Figs.

Flooding d a t a a f e shown is

46 and 4'7 f o r l / b - i n . s o l i d cyl.i.nders and 3/8-in. Raschig r i n g s

respectively

15.2

P r e s s u r e Drop Across t h e Col.wnn

S u r p r i s i n g l y , t h e p r e s s u r e drop a c r o s s t h e colimn w a s observed t o d e c r e a s e w i t h i n c r e a s e s i n water flow rate a t h i g h mercury f l o w r a t e s and low water flow r a t e s .

A t h i g h water f l o w r a t e s , t h e pressure drop

i-ncreased w i t h i n c r e a s e s i n water r a t e as expected.

T h i s e f f e c t was

most a p p a r e n t w i t h 1 / 2 - i n . Raschig r i n g s , a l t h o u g h t h e same b e h a v i o r

i s a l s o observed t o some e x t e n t w i t h 3/8-in.

Raschig r i n g s .

For

example, w i t h 1./2-in. Xaschig r i n g s and a s u p e r f i c i a l mercury v e l o c i t y of 380 f t / h r , t h e column p r e s s u r e d r o p d-ecreased from 1.1 p s i t o 0.2'1 p s i as t h e water v e l o c i t y was i n c r e a s e d from 0 t o 1 2 f t / h r .

This

phenomenon was checked c a r e f u l l y and w a s found t o b e r e p r o d u c i b l e . 'The p r e s e n t d a t a f o r p r e s s u r e d r o p with 1/2-in. Raschig r i n g s a r e conf u s i n g and d i f f i c u l t t o r e p r e s e n t .

1.t i s i n t e r e s t i n g t o n o t e ( F i g . 4 5 )

t h a t t h e r e w a s no s i g n i f i c a n t d e c r e a s e i n dispersed-phase holdup when water flow w a s i n i t i a t e d . On t h e a v e r a g e , t h e mercury i s not b e i n g a c c e l e r a t e d while flowing

through t h e col-umn.

Thus, t h e weight of t h e mercury must b e suppor-Led

by i n t e r a c t i o n w i t h t h e continuous phase and w i t h the packing.

i n t e r a c t i o n w i t h t h e packing were n e g l i g i b l e , t h e p r e s s u r e drop i n

t h e continuous phase would b e e q u a l t o the sum o f t h e f o r c e on t h e

column wa1.l. and t h e q u a n t i t y ( A p ) X , where Ap i s t h e d i f f e r e n c e i n t h e d e n s i t i e s o f t h e two f l u i d s and X i s t h e f r a c t i o n of the column v o i d volurne t.kat; i s occupied by t h e d i s p e r s e d phase.

The observed p r e s s u r e

105

I I 1

QRNL D W G 7 0 - I I O 5 3 R I I 1 I

I t

i +

1I N D I C A T E S

FLOODING

DlSP ERSED- PHASE SUPERFICIAL VELQCIT 0 - i

36 - A

68-0

102-4 139 --'I

20 30 50 100 200 300 500 C o n t i n u o u s - Phase S u p e r f i c i a l V e l o c i t y ( f t / h r )

I000

Fig. 41. Variation or" Column Pressure Drop w i t h S u p e r f i c i a l Water Velocit,y and Dispersed-Phase Superficial Velocity for 1./4-in. Cy:Li.ndrica,l. Packing in it 2-in,-diam Colutnri.

106

10.0

vd (ft/hr)

36 68

A 0

102

r.3

v 6

i39 172 0.1 - t

I-

100 SUPERFICIAL WATER VELOCITY, VC (ft/hr)

600

Fig. 42. Variation of Column Pressure Urop w i t h Superficial Wat,er Velocity and Dispersed-Phase Superficial Velocity for 3/8--in. Raschig ning Packing i.n a ?-iti.-diam Column.

0.8

O R N L D W G 70-11050

DISPERSED-PHASE SUPERFICIAL VELOCITY 0 - 3 6 ftlhr

- 68 f t / h r A - 102 f t l h r 0

A 139 f t / h r Vs = 315.4 ft/hr

0.6

a =I

I 0,

& 0.4

'0 0,

cn L

u) .^

0.2

100

120

Continuous- Phase S u p e r f i c i a l V e l o c i t y ( f t / h r ]

F i g . 43.

140

V a r i a t i o n of Dispersed-Phase Holdup with Continuous- and

Di spersed-Phase Superficial. V e l o c i t i e s for 1 / 4 - i n . Sol.id C y l i n d r i c a l P a c k i n g in a 2-in.-diam Column.

1.08

O R N L DWG 70-3005Rl

SUPERFICIAL SLIP VELOCITY: 819 f+/hr I PACKING in RASCHIG RINGS DISPERSED PHASE SUPER FlClAL VELOCITY

3/e-

P LI1

cn Q

LJJ

cn CT

I I I/)

n ~

400

303

20c

CONTINUCUS PHASE S U P E R F I C I A L VELOCITY !

tt/

b,r!

I' I#. I+)+. Variati~onof Dispersed-Phase Hol.diip w i t h Continuous- a n d Dispersed-Phase S u p e r f i c i a l Velocitiez for 3/8-in. Raschig Rings i n a 2In.--dlam Column. -7.

1 DISPERSED

- PHASE

ft/hr

.-if7

tt/hr

0-246

ft/hr

a 3

ft/hr

A-300 ft/hr

A-390 ft/hr

1330 f t / h r

O R N L D W G 70-11051

SUPERFlClAL VELOCITY

- 93 0 - I50 0

0.4

0.3

n L: I

.E 0.2

0.I

I I I 100 200 300

Continuous- Phase Superficial Vcloci t y ( f t / h r )

F i g . )+?. V a r i a t i o n of Dispersed-Phase Holdup w i t 1 1 Continuous- and D i spersed-Phsse Superficial V e l o c i t i e s for 1 / 2 - i n . Rasehig Rings i n a 2.-i ri -di run Column

11.0

2 4 6 8 IO 12 14 16 18 28 22 24 26 Square Root Of-Continuous- Phase Superficial V e l o c i t y ( f t / h r ) 1/21

Fig.

46. Predicted

C y l i n d r i c a l Packing.

and Measured Flooding Rates w i t h 1 / 4 - i n .

Solid

111

-$ in.

RASCHIG R I N G S

Fig. 147. Predicted and. Measured F l o o d i n g Zates in a Packed CoJ.i.rn~n During Countercurrent, Flow oL' Meroin-y and Water.

112 d r o p i s l e s s t h a n t h e q u a n t i t y ( A p ) X , which i n d i c a t e s t h a t a s u b s t a n t i a l f r a c t i o n o f t h e mercury i s supported by t h e packing.

A decrease i n

pressure drop w i t h o u t a corresponding d e c r e a s e i n dispersed-phase holdup i n d i c a t e s t h a t t h e r e i s a n i n c r e a s e i n t h e i n t e r a c t i o n between t h e mercury and t h e packing.

One can q u a l i t a t i v e l y v i s u a l i z e t h e mercury as flowing through a l l

of t h e c h a n n e l s between t h e packing when t h e r e i s no water flow.

When

a water flow i s s t a r t e d , i t lis p o s s i b l e thai; t h e mercury will flow

p r e f e r e n t i a l l y through on1.y p a r t of t h e c h a n n e l s .

I n such a c a s e ,

h i g h e r mercury v e l o c i t i e s would. be o b t a i n e d and i n c r e a s e d i n t e r a c t i o n of t h e d i s p e s s e d phase w i t h t h e packing would o c c u r .

A quantitative

t r e a t m e n t of t h i s phenomenon has n o t been developed.

15.3

Dispersed-Phase Boldup

S e v e r a l methods, i n c l u d i n g a n e x p r e s s i o n used by Prati; r e l a t i o n developed e a r l i e r by Lhe a u t h o r s , c o r r e l a t i n g holdup d a t a .

and a

have been suggested f o r

The p r e s e n t data i n d i c a t e t h a t holdup can

be c o r r e l a t e d i n terms of a c o n s t a n t s1.i;~ v e l o c i t y , Vs,

which i s

d e f i n e d as:

vs where V V

s C

vC 3.-x

(57)

x ,

= superficial s l i p velocity, = continuous-phase s u p e r f i c i a l v e l o c i t y ,

Vd = dispersed-phase s u p e r f i c i a l v e l o c i t y ,

= dispersed-phase holdup.

The c u r v e s drawn through t h e holdup data i n F i g s . 43,

44, and IC5

correspond t o a c o n s t a n t s l i p velocLty for each packing m a t e r i a l .

For

a g i v e n packing, t h e s l i p v e l . o c i t y w a s o b t a i n e d by a v e r a g i n g s l i p

v e l o c i t y v a l u e s c a l c u l a t e d for each d a t a p o i n t from Eq. ( 5 7 ) . The s t a n d a r d d e v i a t i o n s of t h e average s l i p v e l o c i t y t h u s c a l c u l a t e d

10 t o

F E T ~

l 5 $ , which i s e s t i m a t e d t o h e the e x p e r i m e n t a l e r r o r j.n t h e

holdup d a t a .

'There are s i g n i f i c a n t d e v i a t i o n s between t h e c a l c u l a t e d

and measured holdup d a t a f o r holdup v a l u e s below lo%,

d a t a for 1 / 4 - i n .

and 3/8-in.

d i c t e d holdup v a l u e s .

Otherwj-se, t h e

packing show no t r e n d away from t h e pre-

The p r e d i c t e d holdup v a l u e s f o r 1 / 2 - i n .

Raschig

r i n g s a r e h i g h e r t h a n t h e measured v a l u e s a t low mercury s u p e r f i c i a l velocities.

T h i s t r e n d i s not considered t o be s i g n i f i c a n t s i n c e it

i o n o t confirmed by d a t a from o t h e r packing materials.

vo>

Average v a l u e s were a l s o c a l c u l a t e d f o r t h e c h a r a c t e r i s t i c v e l o c i t y , 24 suggested. by P r a t t and d e f i n e d as

v0 =

(1 - X I 2

x(l

-x)

The s t a n d a r d d e v i a t i o n r e s u l t i n g from assumption of a c o n s t a n t charact e r i s t i c v e l o c i t y was l a r g e r t h a n t h a t r e s u l t i n g from assumption o f a c o n s t a n t s l i p v e l o c i t y , and a dependence of V

on holdup ( o t h e r t h a n

t h a t shown above) was n o t e d . The holdup d a t a f o r 1 / 4 - i n . Raschig r i n g s and 1 / 4 - i n .

i n 1- and 2-in.-diam

solid cylinders

columns s u g g e s t t h a t t h e s u p e r f i c i a l s l i p v e l o c i t y

i s p r o p o r t i o n a l t o t h e packing v o i d f r a c t i o n , as shown i n F i g .

48.

The

s x p e r f i c i a l s l i p v e l o c i t y i s a l s o expected t o be dependent on packing size,

The s l i p v e l o c i t y f o r 3/8-in.

Raschig r i n g s (819 f t / h r ) i s not

s i g n i f i c a n t l y h i g h e r t h a n t h a t f o r 1/4-in0 packfng when a c o r r e c t i o n

i s made f o r t h e d i f f e r e n c e i n packing v o i d f r a c t i o n .

However, t h e s l i p

v e l o c i t y f o r 1 / 2 - i n , Raschig s i n g s (1530 f t / h r ) i s c o n s i d e r a b l y h i g h e r t h a n t h a t f o r t h e smaller packing s i z e s .

15.4

CorrelaLion of Flooding R a t e s

The o b s e r v a t i o n t h a t t h e dispersed-phase holdup d a t a can be c o r r e l a t e d on t h e b a s i s of a c o n s t a n t s u p e r f i c i a l s l i p v e l o c i t y i s e s p e c i a l l y important s i n c e t h i s s u g g e s t s a method f o r c o r r e l a t i n g f l o o d i n g d a t a . A t f l o o d i n g , it i s assumed t h a t t h e following c o n d i t i o n s e x i s t :

114

RASCH RINGS

0.I

0.2

0.3

ekinn V oid .P n--..,...-.-

0.4 F . raction

8.5

0.6

8.7

f i g . 48. V a r i a t i o n o f Superficial S l i p Velocity wi-ih Packi.ng Void I.'ract.ion f o r 1/4-j.n. P a c k i n g i n I-in. and ?--in.-diam Colirmns. - 7 ,

11'5

-ad'- - -

avC

- 0 .

(59)

Partial differentiation of Eq. (57) with respect to X, the dispersed-

phase holdup, yields the relation

(1 - x ) 2

vd + -1 - =c o . C - x ax - x ax X2

If the conditions stated by Eq. (59) are met at flooding, Eq. (60) reduces

,flood

(1 -

'd,flood

Multiplying Eq. (57) by 1/(1 - X ) and combining the resulting equation wlth E q . (61) yields the following relation: Vd,flood X2

'd,flood

x ( l - x)

1-x

which reduces to

Multiplying Eq. (57)by 1 / X and combining the resulting equation with Eq. (61) yields the relation c'

flood

lY=T-E+(1 - X

which reduces to

Vc,flood = - s

(62)

116

1-x=

E l i m i n a t i o n of X from E q s , ( 6 3 ) and

vher e

= continuous-phase s u p e r f i c i a l v e l o c i t y a t f l o o d i n g ,

' c ,flood d'

( 6 5 ) yields the final relation

= dispei-sed-phase s u p e r f i c i a l v e l o c i t y a t f l o o d i n g .

,f l o o d

Thus, i f t h e s u p e r f i c i a l s l i p v e l o c i t y remains c o n s t a n t up t o f l o o d . i n g ,

a plot of

(vc , f l o o d )1/2 vs

having a s l o p e of -1.

('d,flood

)l/* should produce a s t r a i g h t l i n e

S b i l a r f l o o d i n g c u r v e s w i t h s l o p e s near -3 have

been observed i n t h e l i t e r a t u r e , 2 5 and our e a r l i e r ( l a t a f o r 3/8-in.

Raschig r i n g s and 1 / 4 - i n .

t h i s manner

1 / 4 - and

so1i.d c y l i n d e r s were correl.ated i n

Recent r e s u l t s o b t a i n e d w i t h 1 / 4 - i n .

3/8-in. Raschig r i n g s , s h o ~ ni n F i g s .

1.16

and

sol.id c y l i n d e r s and

47, a r e al.so r e p r e s e n t e t l

well. by t h i s c o r r e l a t i o n .

15.5 P r e d i c t i o n of Molten-Salt--Bismuth i n Packed Columns

Flooding Rates

We have a t t e m p t e d t o extend t h e c o r r e l a t i o n s developed f o r Lhe mercury-water

system i n o r d e r t o o b t a i n r e l a t i o n s that are a p p l i c a b l e

t o molten-salt--bismuth

systems.

were not v a r i e d i n t h e s e s t u d i e s .

The p h y s i c a l p r o p e r t i e s of t h e f l u i d s Significant differences i n properties

e x i s t between t h e mercury-water system and molten-salt--bismuth

systems;

p o t e n t i a l l y important d i f f e r e n c e s i n c l u d e t h e v i s c o s i t y of t h e contlinuous p h a s e , t h e d t f f e r e n c e i n t h e d e n s i t i e s of t h e p h a s e s , and t h e i n t e r f a c i a l tension.

The c o r r e c t i o n a s s o c i a t e d w i t h d i f f e r e n c e s i n i n t e r f a c i a l

t e n s i o n i s b e l i e v e d t o be s m a l l s i n c e t h e i n t e r f a c i a l t e n s i o n f o r the mercury-xater system i s approximately equal. t o t h a t f o r a molten-salt-b t s m u t h system.

A s t h e d i s p e r s e d phase f l o w s down t h e column, it i n t e r a c t s w i t h

b o t h t h e packing and t h e c o n t i n u o u s phase.

I n t e r a c t i o n w i t h t h e con-

t i n u o u s phase i s i n e r t i a l i n n a t u r e , and t h e continuous-phase v i s c o s i t y i s expected t o have o n l y a s l i g h t e f f e c t .

If t h e p r i n c i p a l i n t e r a c t i o n

were between t h e two f l u i d s , t h e s l i p v e l o c i t y would be p r o p o r t i o n a l t o t h e s q u a r e r o o t of t h e d i f f e r e n c e i n d e n s i t i e s of t h e f l u i d s .

noted e a r l i e r , however, t h e metal phase i s more n e a r l y supported by i n t e r a c t i o n w i t h t h e packing; for t h i s c o n d i t i o n , it i s e s t i m a t e d

t h a t t h e s l i p velocity i s directly prosortional t o the difference i n t h e d e n s i t i e s of t h e p h a s e s . On t h e b a s i s of t h e s e c o n s i d e r a t i o n s , t h e s u p e r f i c i a l s l i p veloci t y w a s assumed t o be p r o p o r t i o n a l t o b o t h t h e packing v o i d f r a c t i o n arid t h e d i f f e r e n c e i n d e n s i t i e s of t h e p h a s e s .

The r e s u l t i n g r e l a t i o n

f o r t h e f l o o d i n g rates i n a s a l t - b i s m u t h system i s , t h e n :

('c , f l o o d

where

)1/2

c' , f l o o d 'd,flood

's,Bg-H 2 0 AD

continuous-phase s u p e r f i c i a l v e l o c i t y a t f l o o d i n g ,

- dispersed-phase s u p e r f i c i a l v e l o c i t y a t f l o o d i n g , - s u p e r f i c i a l s l i p v e l o c i t y f o r mercury-water w i t h t h e t y p e packing t o b e u s e d ,

system

= d i f f e r e n c e i n d e n s i t i e s of t h e phases, d i f f e r e n c e i n d e n s i t i e s of mercury and. water, packing v o i d f r a c t i o n ,

ref

- v o i d f r a c t i o n of packing f o r which Vs determined.

g-H20

was

16.

REFERENCES

1..

L . M . F e r r i s , ORNL, p e r s o n a l c o m l u n i c a t i o n .

M. J . B e l l , ORNL, personal communication.

M. S . Bau:tista and L. E. McNeese, "Axial Mixtng i n a n Open Bubble Column , ' I RngineeringJevelopmenL - . l l l S_ t u~d i e s f o r Molten-Salt Breeder -Reactor . P r o c e s s i n g No. I + , ORNL-TM-3139 ( i n p r e s s ) I

A . M. Skeikh and J . D. D e a r t h , A x i a l Mixing i n an Open Bubble Col.umn , MIT-CEPS-X-91 (December 1.969)

W. Kee and L. E. McNeese, E n . i n e e r i n g Development S t u d i e s f o r pp. Mal-ten-Salt Breeder Reactor P r o c e s s i n g No. 3 ORNL-TM-3138

39-50.

J . R . Hightower, J r . , e t al. , "Design and I n s t a l l a t i o n of t h e F l o w E l e c t r o l y t i c C e l l F a c i l i t y , " E n g i n e e r i n g D e v.-e l o z n t Studis2-for Molten-Salt Breeder Reactor P r o c e s s i n g No. 4, ORNL-TM-3139 ( i n press).

C . W. Kee and B. A. Bannaford, " C a l i b r a t i o n of an Orifice--Head Pot FlowneLer ) I ' Engineering Development S t u d i e s for Molten-Salt Breeder Reactor P r o c e s s i n g No. 4, ORNL-TM-3139 ( i n p r e s s ) .

J . R . R e i t z and F. J . M i l f o r d , Foundations o f Electroinagnetic Theory , 2d ed. , p . 1.36, Addison-Wesley , Readtng , Mass. , 1967.

T . R. Johnson, F. G . Teats, and H. I). P r i c e , An I n d u c t i o n Probe -~ for Measuring Liquid Levels i n Liquid Metals, ANL-7153 (February

10.

5. Roth and L. E . McNccse, "Bisuii.iLh-Salt I n t e r f a c e D e t e c t o r Engineering Development S t u d i e s far Molten-Salt Breeder Reactor P r o c e s s i n g No. 4 , ORNL-'I'M-3139 ( i n p r e s s ) .

11. J. H. S h a f f e r , MSfi Program Semiann. P r o g r . iiept. J u l y 31, ORNL-3708, pp. 288-303.

1964,

12.

J . R . Hightower, J r . , and L. E . McNeese, Engineering Development S t u d i e s for Molten-SgLt B r e e d e ~ a ~ - e a c t oProL3sslng r No. 3 , ORNLTM-3138, pp. 84-95.

13.

F. J . Smith, L . M . F e r r i s , and C. T. Thompson, Liquid-Vapor Equil.ibz>-z l2%F Systems, ORNL-I+)+15 ( J u n e 1969).

1.h.

Hightower, Jr., and L. E. McNeese, Measurement of t h e R e l a t i v e V o l a t i l i t i e s of Fl.uoi-ides of C e , L a , PI-,N d , Sm, Eu, B a , S r , Y , ORNL-TM-2058 ( J a n u a r y 1968 ) and Zr i n Mixtui-es of JLiF-BeF 2' J . R.

I_-._

15;.

M. S. F o s t e r , S. E . Wood, and C . E . Crouthamel, I n o r g . Chem. 3, 1428 (1964).

16. B.

17*

V. Ibl and B. F. Dodge, Chem. Eng. S c i .

120

(1953).

Handbook of Chemistry and P h y s i c s , 41st e d . , p. 2343, Chemical Rubber P u b l i s h i n g Co., C l e v e l a n d , Ohio, 1960.

45, 375 (1966). IC. A. K. F i s c h e r , J. Chem- Phys, -

19. Leon Lapidus, D i g i t a l Computation f o r Chemical E n g i n e e r s , p. 288, McGraw-Hill, New York, 1962. 20. M. Hansen, C o n s t i t u t i o n of Binary A l l o y s , 2d e d . , p . 316, McGrawH i l l , New York, 1958. 21..

J. S. Watson and H. D. Cochran, J r . , " E f f e c t of Axial Mixing i n Packed Colwrul C o n t a c t o r s Used f o r MSBR P r o c e s s i n g , " Engineering D No. 4 , ORNL-TM-3139 ( i n press).

22.

J . S . Watson and L. E , McNeese, Unit O p e r a t i o n s S e c t i o n Quarterly_ P r o g r e s s R e p o r t , July-September 1368, ORNL-4366, pp. 57-98.

23. A. J . F r e d e r i k s e n , J . J . P r o t u l p a c , and S. C . Trindade, Hydrodynamics o f a Mercury-Water Packed Column , MIT-CEPS-X-88 (1969 )

24.

R. Gayler and H. R. C. P r a t t , "Holdup and Pressure Drop i n Packed Columns," Trans. I n s t . Chem. Eng. 29, 1 1 0 (1951).

25.

F. R. D e l l and H. R. C . P r a t t , T r a n s , Inst. Chem. Eng.

(1951) e

3, 89-109

3-21

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