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Design, construction, and operation of a piston type sampler for a liquid-liquid extraction spray column Hawrelak, Richard Alan 1960

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DESIGN, CONSTRUCTION, AND OPERATION OE A PISTON TYPE SAMPLER FOR A LIQUID-LIQUID EXTRACTION SPRAY COLUMN b y RICHARD ALAN HAWRELAK B.A.Sc, U n i v e r s i t y of B r i t i s h Columbia, 1958 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n the Department of CHEMICAL ENGINEERING We accept t h i s t h e s i s as conforming to the r e q u i r e d standard The U n i v e r s i t y of B r i t i s h Columbia June, I960 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study. I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s understood t h a t copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be allowed without my w r i t t e n p e r m i s s i o n . Department o f C^u^ryiJ^&A The U n i v e r s i t y of B r i t i s h Columbia, Vancouver $, Canada. Date 4-. i i ABSTRACT A p i s t o n type of sampler was designed and c o n s t r u c t e d to sample the d i s p e r s e d phase of a spray l i q u i d - l i q u i d e x t r a c t i o n tower. The aim was to check a previous method of sampling the d i s p e r s e d phase. This method depended on the use of a long probe which descended i n t o the column from above and through which samples were removed by s u c t i o n . C a l c u l a t e d v a l u e s of the d i s p e r s e d phase c o n c e n t r a t i o n u s i n g the p i s t o n type sampler were found to be g e n e r a l l y lower than the corresponding c o n c e n t r a t i o n s u s i n g the d i s p e r s e d phase probe. The system s t u d i e d was methyl i s o b u t y l ketone (the d i s p e r s e d p h a s e ) - a c e t i c a c i d (the s o l u t e ) - water (the continuous phase). The s o l u t e was t r a n s f e r e d from the aqueous phase, which was s a t u r a t e d w i t h methyl i s o b u t y l ketone, to the organic phase, which was s a t u r a t e d w i t h water. Mass t r a n s f e r data were gathered f o r t h i s system i n a 1 . 5 - i n . I.D. column which was approximately 7 » 3 - f t . i n h e i g h t . i i i TABLE OF CONTENTS Page INTRODUCTION 1 EXPERIMENTAL METHODS . . . .. 5 Apparatus 5 Procedure 36 CALCULATIONS 49 RESULTS.... , 56 DISCUSSION 69 Operating C o n d i t i o n s 69 C r o s s - S e c t i o n a l C o n c e n t r a t i o n Measurements 71 P i s t o n Samples Compared to Probe Samples I.. 74 Approximation of E r r o r s 82 Salinometer Measurements 85 CONCLUSIONS 86 NOMENCLATURE 88 LITERATURE CITED 91 APPENDIX I - Sample C a l c u l a t i o n s 94 I I - Volume Changes Due To Changes I n Mutual S o l u b i l i t y 99 i v LIST OP TABLES Table Page I. Key to Figure 2 . . . . 7 II. Calibration of Salinometer 46 III. Sampling Rate and Purging Time 59 TV". Gver-all Transfer Data 60 7. Concentration Profiles in Cross-Sections Perpendicular to the Column Axis As Determined By Sampling With The Hypodermic Syringe 61 VI. Concentration of the Water Phase at Position 6 as a Function of Time After Start-Up of a Run 62 VII. Hypodermic Syringe Sampling Rates 65 VIII. Concentrations and Comparison of Piston and Probe Samples 65 IX. Results of Immediate Separation of the Two Phases in the Piston Samples of Run 85 66 X. Maximum Approximate Error of Calculated Ini t ia l Ketone Concentration, G k i . . . 67 XI. Comparison of Two Methods of Analysis 68 XII. Simulated Piston Samples 84 XIII. Summary of Results For Sample Calculation No. 7 104 V LIST OF FIGURES Figure Page 1. Sampling Tubes i n Operation 2 2. Schematic Flow Diagram 6 3. P i s t o n 10 4. Boring Holes Through P i s t o n Walls 11 5. Coating P i s t o n With S o l d e r 12 6. Machining S o l d e r Surface of P i s t o n 13 7. P i s t o n Block 15 8. B o r i n g of I.D. of P i s t o n Block 16 9. Completion of B o r i n g I.D. of P i s t o n Block 16 10. Reduction of Weight of P i s t o n B l o c k 17 11. Damage to Aluminum P i s t o n A f t e r S e i z u r e 19 12. S c o r i n g on C y l i n d e r Walls 19 13. C o l l e c t i o n Funnel F i t t e d t o Underside of P i s t o n Block 21 14. C o l l e c t i o n Funnel..... 22 15. Assemblage of Components of Funnel 23 16. C o l l e c t i o n F l a s k 24 17. C o l l e c t i o n F l a s k Drawing 25 18. F l a s k Held i n P o s i t i o n by Tension Springs t o P i s t o n Block 26 19. Column Support i n E a r l y Stages of C o n s t r u c t i o n . . 27 20. Column Support 28 v i F i g u r e Page 21. B r a c i n g P a t t e r n of Column Support 29 22. Assembled Column 29 2 3 . E l g i n Head Support 31 24. C o n i c a l S e c t i o n Support 32 2 5 . E l g i n Head and I t s Support 33 26. C o n i c a l S e c t i o n and I t s Support 33 2 7 . Clamping Arrangement 34 28. Sampler Support 35 29. Clamping Arrangement f o r P i s t o n Sampler Support. 36 30. Tip P a t t e r n s f o r Ketone Nozzle 39 31. S i m p l i f i e d Bridge C i r c u i t 45 3 2 . Salinometer C a l i b r a t i o n Curve... 47 33. S i m p l i f i e d Drawing of Sampling Procedure 51 34. P o s i t i o n s i n Column C r o s s - S e c t i o n s at Which Hypodermic Syringe Samples Were C o l l e c t e d 64 3 5 . Mutual S o l u b i l i t y Curve f o r the System Methyl I s o b u t y l Ketone-Acetic Acid-Water, at 2 5 ° C . . . 100 36. S i n g l e - s t a g e Contact E x t r a c t i o n Mixer 101 ACKNOWLEDGEMENTS The author would l i k e t o express s i n c e r e thanks t o Dr. S.D. Cavers f o r the a s s i s t a n c e , and h e l p f u l c r i t i c i s m s o f f e r e d throughout the course of t h i s p r o j e c t . Thanks are a l s o due t o Dr. J.D.H. S t r i c k l a n d , S e n i o r S c i e n t i s t , of the P a c i f i c Oceanographie Group, Nanaimo, B.C., f o r the use of h i s sal i n o m e t e r . A p p r e c i a t i o n i s expressed to the N a t i o n a l Research C o u n c i l of Canada f o r f i n a n c i a l a s s i s t a n c e . 1 INTRODUCTION In continuous countercurrent s o l v e n t e x t r a c t i o n columns, many attempts have been made to o b t a i n mass-transfer c o e f f i c i e n t s by measuring c o n c e n t r a t i o n d i s t r i butions w i t h i n an e x t r a c t o r (1 ,2 ,3 ,4 ,5 ,6 ,7) ' This approach should be more accurate than the a l t e r n a t i v e of u s i n g a l o g a r i t h m i c mean d r i v i n g f o r c e computed o n l y from the c o n c e n t r a t i o n s of the incoming and outgoing streams. Cavers and Ewanchyna (2), and Choudhury (1) measured c o n c e n t r a t i o n p r o f i l e s by i n t e r n a l sampling of both the continuous and d i s p e r s e d phases. I n t h e i r work the authors obtained samples by means of lo n g , s t a i n l e s s s t e e l tubes which descended i n t o the column to any d e s i r e d height ( l a ) . Figure 1 i s a photograph of a s e c t i o n of the column showing Choudhury's sampling tubes i n o p e r a t i o n . G i e r and Hougen (3) a l s o measured c o n c e n t r a t i o n p r o f i l e s f o r both phases. Cavers and Ewanchyna (2) and Choudhury (1) r e p o r t e d c o n c e n t r a t i o n p r o f i l e s which showed a co n s i d e r a b l e end e f f e c t at the continuous phase i n l e t to the column under c e r t a i n o p e r a t i n g c o n d i t i o n s . Other workers (4,5,6,7) who sampled o n l y the continuous phase of spray columns, a l s o r e p o r t e d a F i g u r e 1. Sampling Tubes i n O p e r a t i o n c o n s i d e r a b l e end e f f e c t a t the continuous phase i n l e t t o the column. T h i s end e f f e c t i s m a n i f e s t e d by the c o n t i n u o u s phase c o n c e n t r a t i o n p r o f i l e showing a d i s c o n t i n u i t y a t t h i s p o i n t . From the p o i n t of view of the continuous phase an unexpectedly l a r g e p o r t i o n of the t o t a l e x t r a c t i o n appears t o take p l a c e when the drops of the d i s p e r s e d phase c o a l e s c e a t the i n t e r f a c e at the top of the column. G e a n k o p l i s and Hixson (4) a t t r i b u t e d t h i s end e f f e c t t o t u r b u l e n c e caused by the c o a l e s c e n c e of the drops, but suggested t h a t changes i n i n t e r f a c i a l t e n s i o n might a l s o be i m p o r t a n t . Newman (8) suggested t h a t the end e f f e c t found by Geankoplis et a l at the continuous phase i n l e t was the r e s u l t o f v e r t i c a l m ixing of the continuous phase due to the movement of the drops. Cavers and Ewanchyna ( 2 ) , upon o b t a i n i n g c o n c e n t r a t i o n p r o f i l e s f o r each phase, noted d i s c o n t i n u i t i e s i n b o t h p r o f i l e s at the i n t e r f a c e . For t r a n s f e r of a c e t i c a c i d from the continuous aqueous phase to the d i s p e r s e d ketone phase the d i s c o n t i n u i t y i n the water c o n c e n t r a t i o n p r o f i l e c o uld be broken i n t o two p a r t s : one r e p r e s e n t i n g the e f f e c t s of drop a g i t a t i o n at the i n t e r f a c e , and the other the e f f e c t of back- mixin g i n the aqueous phase. The d i s c o n t i n u i t y i n the ketone phase c o n c e n t r a t i o n p r o f i l e was due o n l y to the a g i t a t i o n e f f e c t ( 2 ) . Choudhury, i n j u s t i f y i n g h i s sampling technique ( l b ) , suggests t h a t the r a t e of sampling may be an important f a c t o r t o be c o n s i d e r e d i n i n t e r p r e t i n g the r e s u l t s o b t a i n e d . Low sampling r a t e s tend t o produce drop coalescence at the d i s p e r s e d phase sampling probe entrance, which c o u l d i n f l u e n c e the c o n c e n t r a t i o n of the drops by a s i m i l a r phenomenon to t h a t j u s t d e s c r i b e d as t a k i n g p l a c e at the column i n t e r f a c e . High sampling r a t e s , on the other hand, would cause d i s t u r b a n c e s i n the steady s t a t e o p e r a t i o n of the column a t the p o i n t of sampling, and, i n t u r n , i n f l u e n c e the c o n c e n t r a t i o n of both phases throughout the column. 4 While removing d i s p e r s e d phase samples at low sampling r a t e s , Choudhury noted t h a t the ketone drops d i d not r i s e immediately up the d i s p e r s e d phase probe. The drops l i n g e r e d at the entrance f o r a short time (see F i g u r e 1 ) , co a l e s c e d , and then passed up through the probe i n t o the sampling f l a s k s . I t was suggested t h a t t h i s short residence time and coalescence of the ketone drops at the probe entrance would a l l o w an e x t r a amount of a c e t i c a c i d to be t r a n s f e r r e d i n t o the ketone drops and t h e r e f o r e produce e r r o n e o u s l y h i g h r e s u l t s f o r d i s p e r s e d phase c o n c e n t r a t i o n s . Under h i g h e r sampling r a t e s t h i s l i n g e r i n g and coalescence of ketone drops at the probe entrance was not observed. V a r i a t i o n s i n sampling r a t e s produced no a p p r e c i a b l e changes i n the measured probe c o n c e n t r a t i o n s of e i t h e r phase (lc)T The present i n v e s t i g a t i o n was designed to give another independent method of sampling the d i s p e r s e d phase i n order t o check the probe method. The system s t u d i e d was a c e t i c a c i d - methyl i s o b u t y l ketone-water. Much of the apparatus was the same as t h a t used by Choudhury. However, a p i s t o n type sampling device was designed and c o n s t r u c t e d to remove q u i c k l y a sample of both phases from the e x t r a c t i o n column which had been o p e r a t i n g under steady s t a t e c o n d i t i o n s . Although mass t r a n s f e r between the d i s p e r s e d phase and the continuous phase continued a f t e r removal o f the sample from the column by means of t h i s p i s t o n , i n i t i a l ketone c o n c e n t r a t i o n s c o u l d be * As p o i n t e d out l a t e r the c o n d i t i o n s under which these sampling r a t e experiments were made were f a r from i d e a l s i n c e at the l o c a t i o n s t u d i e d the phases were near e q u i l i b r i u m . 5 c a l c u l a t e d . These have been compared w i t h the c o n c e n t r a t i o n s of ketone samples which were taken w i t h the ketone phase probe at the same l o c a t i o n and under the same o p e r a t i n g c o n d i t i o n s as a p p l i e d when the p i s t o n sample was taken. Numerous c r o s s - s e c t i o n a l c o n c e n t r a t i o n t r a v e r s e s of the continuous water phase were made u s i n g hypodermic s y r i n g e s , the needles of which entered the column through the asbestos gaskets a t g l a s s to g l a s s f l a n g e s . E xperimental work was l i m i t e d because of c o n s t r u c t i o n d e l a y s . However a s u f f i c i e n t amount of data was c o l l e c t e d t o d i r e c t f u t u r e s t u d i e s . EXPERIMENTAL METHODS Apparatus Plow O u t l i n e A schematic f l o w diagram of the apparatus i s shown i n F i g u r e 2, which i s a s l i g h t m o d i f i c a t i o n of t h a t g i v e n by Choudhury ( I d ) . A key t o F i g u r e 2 i s presented i n Table I . The d e t a i l e d d e s c r i p t i o n o f much of the apparatus has been presented by Choudhury (1) and others and w i l l not be repeated here. FIGURE 2. SCHEMATIC FLOW DIAGRAM Table I Key t o Fi g u r e 2 A - Continuous phase f e e d tank B - Continuous phase r e c e i v e r and storage tank C - Dispersed phase r e c e i v e r and storage tank D - Dispersed phase feed tank E - Continuous phase constant head tank F - Dispersed phase constant head tank G - Continuous phase rotameter H - Dispersed phase rotameter I - Continuous phase i n l e t sample v a l v e J , , Jp - Continuous phase f l o w r a t e c o n t r o l v a l v e s K,,K 2 - Dispersed phase f l o w r a t e c o n t r o l v a l v e s L - Dispersed phase i n l e t sample v a l v e M - 6 i n c h I.D. top end s e c t i o n N - Continuous phase i n l e t p i p e s 0 - D r a i n v a l v e f o r top end s e c t i o n P, , Pp - C e n t r i f u g a l f e e d pumps f o r continuous and d i s p e r s e d phases r e s p e c t i v e l y Q - L e v e l of I n t e r f a c e R - Column proper Vfc. i n c h I.D. S - Dispersed phase n o z z l e T ^ T2,' T^, T^ - Thermometers U - Bottom end s e c t i o n V - Vent t o atmosphere W - Pressure e q u a l i z i n g vent X - C o n t r o l f o r i n t e r f a c e l e v e l PS-p PS£ - P i s t o n samples PTS - P i s t o n Type Sampler m - Mercury manometer h, k, - Sampling b o t t l e s n - A s p i r a t o r a, b, - S t a i n l e s s s t e e l sampling tubes e, f , - Sample v a l v e s c - Wooden block to which sampling tubes are attached d - Sca l e 8 The c e n t r i f u g a l feed pumps P^, and P 2 , supply water and ketone t o constant head tanks which i n t u r n supply these phases to rotameters f e e d i n g the column. Methyl i s o b u t y l ketone (ketone) i s pumped from the aluminum storage tank ( I f ) , D i n F i g u r e 2, t o a constant head tank ( 8 ) , F i n Fi g u r e 2. P a r t of the org a n i c phase overflows back to the storage tank, D, w h i l e the d e s i r e d amount f l o w s by g r a v i t y through rotameter, H, and then t o the d i s p e r s e d phase n o z z l e ( I f ) , S i n F i g u r e 2. The n o z z l e d i s p e r s e s the ketone phase i n t o drops which r i s e c o u n t e r c u r r e n t l y t o the descending water phase. The ketone drops e v e n t u a l l y coalesce i n the upper expanded s e c t i o n ( 8 ) , M i n F i g u r e 2, and are removed from the top of the column to the storage tank, C. The aqueous phase i s pumped from storage tank, A, t o the constant head tank, E, where p a r t r e t u r n s to the storage tank, A, and the d e s i r e d amount flows through rotameter, G. The water phase dis c h a r g e s through two 1/8-inch Schedule 4-0 Type 304 s t a i n l e s s s t e e l p i p e s , N, i n t o the bottom of the expanded s e c t i o n , M. I t then flows through the column, R, and up t o the i n t e r f a c e c o n t r o l l e r ( I ) , X i n F i g u r e 2. By v a r y i n g the he i g h t of the i n t e r f a c e c o n t r o l l e r the i n t e r f a c e , Q, i n the expanded s e c t i o n , M, can be a c c u r a t e l y c o n t r o l l e d . The aqueous phase passes from the i n t e r f a c e c o n t r o l l e r arrangement t o storage tank, B. 9 C a l i b r a t i o n curves f o r the rotameters, and e q u i l i b r i u m r e l a t i o n s h i p s were obtained from Choudhury*s work ( l h ) . The sampling tubes ( l i ) , a and b i n F i g u r e 2 , were clamped t o a wooden b l o c k and c o u l d be a d j u s t e d to any d e s i r e d h e i g h t w i t h r e s p e c t t o the n o z z l e t i p s . Sampling r a t e s were c o n t r o l l e d by a vacuum arrangement and by g l a s s c a p i l a r y tubes between the sample v a l v e s , e and f , and the sample c o l l e c t o r s , h and k, r e s p e c t i v e l y i n F i g u r e 2 . Vacuum was c r e a t e d i n the water a s p i r a t o r , n, and c o n t r o l l e d by an a i r vent l e a d i n g from the atmosphere to the bottom of a mercury column the height of which c o u l d be v a r i e d . The sampling apparatus was connected above the s u r f a c e of the mercury, and as l o n g as a i r bubbled through the mercury from the vent the pressure i n the sampling apparatus was approximately constant and equal t o t h a t exerted by the column of mercury. T h i s arrangement i s shown s c h e m a t i c a l l y as valve r i n F i g u r e 2 . By c o n t r o l l i n g the vacuum and by use of the c a p i l a r i e s the sampling r a t e s of each phase c o u l d be a d j u s t e d to any d e s i r e d v a l u e . The p i s t o n type sampler, PTS i n F i g u r e 2 , was f l a n g e d to the g l a s s column by means of standard Corning Type I f l a n g e s and hard asbestos gaskets. I n a l l cases the p i s t o n a x i s was 1 . 5 9-ft. above the n o z z l e t i p s . P i s t o n samples were c o l l e c t e d , at p o i n t s PS^ and P S 2 i n F i g u r e 2 , i n t o s p e c i a l l y designed c o l l e c t i o n f l a s k s by slamming the p i s t o n from one s i d e to the other of i t s t r a v e l . T,-~ I J_ | p t -L. wol l thickness, brass r - column sections. A 5. 8 2 , 1 - 2 0 Allen head set screws 2 — 0 Bolt \ 6„ Circle. - 4 D 3 , 1 — 20,. fiot head screws, countersunk -g- S E C T I O N A - A 50% tin, 50% lead, heat coated to 3gO.C\brass tubing. 8 H3' T Column sections ond brass end plates t ight f i t ted and soldered into piace. F I G U R E 3 • P I S T O N 11 The d e s i g n o f the p i s t o n was such t h a t the o p e r a t i o n o f the column was n o t i n t e r u p t e d . P i s t o n F i g u r e 3» i s a drawing showing the p i s t o n used i n sampling. The p i s t o n was machined from standa r d b r a s s t u b i n g , 3#-in. I.D. by 1 / 8 - i n . w a l l t h i c k n e s s . One q u a r t e r i n c h hard b r a s s p l a t e s were r e c e s s e d to f i t and s o l d e r e d to the ends o f the p i s t o n . A p p r o x i m a t e l y 1 / 3 2 - i n . was then machined o f f the O.D. of the p i s t o n . Two h o l e s were then bored through the p i s t o n w a l l s p e r p e n d i c u l a r to i t s l o n g i t u d i n a l a x i s . See F i g u r e 4. F i g u r e 4. B o r i n g Holes Through P i s t o n W a l l s 12 The diameter of these holes was such that two standard brass pipes, l)4-in. I.D. by 3 / 1 6 - i n . wall thickness, could be f o r c e - f i t t e d into p o s i t i o n . These smaller brass pipes were also soldered to the piston, and, since t h e i r length exceeded the O.D. of the pi s t o n , they had to be machined down to t h i s dimension. These two brass pipes were then bored to l 1/?-in. I.D. Next a coating of a 50-50 mixture of lead and tim was applied to the pi s t o n . See Figure 5. Figure 5. Coating Piston With Solder The coating was allowed to cool completely and then machined to f i t the p i s t o n block within a tolerance of 0.001 inches. See Figure 6. 1 3 F i g u r e 6. Machining S o l d e r S u r f a c e of P i s t o n The p i s t o n i s moved by means of a hand d r i v e n r o d which i s f l a n g e d t o the p i s t o n at one end. The d r i v i n g r o d i s f i x e d t o the f l a n g e by means of two #-in. A l l e n head s e t screws. The p i s t o n d e s c r i b e d above i s j u s t one p i s t o n i n a s e r i e s o f attempts t o a r r i v e a t a combination of p i s t o n and p i s t o n b l o c k dimensions t h a t would a l l o w easy movement and no leakage. The problems i n v o l v e d w i l l be covered i n d e t a i l i n the next s e c t i o n i n which the p i s t o n b l o c k i s d e s c r i b e d . 14 P i s t o n B l o c k The p i s t o n b l o c k was pressure c a s t from phosphor bronze by Mainland Foundry, Vancouver, B.C. I t i s shown i n F i g u r e 7» The hole f o r the p i s t o n was d r i l l e d i n the Chemical En g i n e e r i n g Shop at the U n i v e r s i t y of B r i t i s h Columbia. A photograph of the b l o c k as the I.D. was being bored i s shown i n F i g u r e 8. F i g u r e 9 i s a photograph a f t e r the b o r i n g had been completed. F i g u r e 10.is a photograph of the b l o c k having some of i t s dimensions reduced to decrease i t s weight. A f t e r the I.D. was machined through a s l i g h t t a p e r was found to e x i s t from one end to the ot h e r . The p i s t o n d e s c r i b e d previously'was set i n t o the b l o c k , the b l o c k assembled i n t o the spray e x t r a c t i o n column, and a s i x f o o t head of water was a p p l i e d by f i l l i n g the column to a height of s i x f e e t above the b l o c k . The p i s t o n was found to move f r e e l y i n the b l o c k but leakages as h i g h as 25 mis./min. were encountered. I t was f e l t t h a t the e x i s t i n g t a p e r was the cause of the leakage and tha t t h i s taper should be c o r r e c t e d . The c y l i n d e r was then sent out t o be rebored by Canadian Car P a c i f i c L t d . , Vancouver, B.C. F o l l o w i n g the r e b o r i n g a c o a t i n g of chromium was a p p l i e d e l e c t r o l y t i c a l l y to the c y l i n d e r , but o n l y to the i n s i d e s u r f a c e , by Hudson P l a t i n g , Material : Phosphor Bronze 1 i — i 4- 3" 13, ~ Deep, 4 Holes + 2-- - H i s ^ 4 - 2 i - | t \ J 5f "—KM 3^- Bolt Diameter For 8 Stondard Flange | - I 8 , | Deep 3 Holes Equally Spaced 4.002 Drill, Chromium Plate to 4 .OOf -|~ Drill Through, I g- C'bore 5" Q Deep, 2 Holes l " 1^ Drill Through 2 Bolt Diometer 4 - 2 0 , ^ Deep 3 Holes Equolly Spaced F I G U R E 7. PISTON BLOCK 16 17 F i g u r e 10. R e d u c t i o n of Weight of P i s t o n B l o c k Vancouver, B.C. The c y l i n d e r was t h e n sent back to Canadian Car P a c i f i c L t d . , who then attempted t o hone the i n s i d e s u r f a c e t o the s p e c i f i e d I.D. Some g r i n d i n g was a l s o done a t the ends. In c o n j u n c t i o n w i t h t h i s work a s o l i d aluminum p i s t o n was machined by Canadian Car P a c i f i c L t d . t o f i t the chromed c y l i n d e r . Once a g a i n t h i s p i s t o n b l o c k was s e t up i n the column. The aluminum p i s t o n was put i n t o p l a c e , and a s i x f o o t head of water a p p l i e d t o the assembly. The aluminum p i s t o n was shoved back and f o r t h a few times and i t f i n a l l y s e i z e d c o m p l e t e l y so t h a t i t was i m p o s s i b l e t o move i t . However, no leakage was encountered. 18 The u n i t was taken down again and i t was found t h a t s l i g h t i m p e r f e c t i o n s i n the chromium p l a t i n g and p i s t o n w a l l s had caused the s e i z u r e . The p i s t o n b l o c k was sent back f o r rechroming by Hudson P l a t i n g and l a p p i n g by Canadian Car. The method of l a p p i n g c o n s i s t e d of r o t a t i n g back and f o r t h i n the p i s t o n b l o c k an approximately 21/4-in. long b r a s s c y l i n d e r whose O.D. was approximately Q005 inches l e s s than the I.D. of the p i s t o n b l o c k . A l a p p i n g compound, which c o n s i s t e d of a mixture of emery dust and f i n e grade machine o i l , was used between the two s u r f a c e s . The aluminum p i s t o n was again machined to f i t the rechromed and lapped p i s t o n b l o c k . Upon be i n g set up a t h i r d time the aluminum p i s t o n once again s e i z e d a f t e r a few passages through the c y l i n d e r . F i g u r e 11 i s a photograph of the aluminum p i s t o n showing the damaged s u r f a c e , whereas F i g u r e 12 shows the corresponding s c o r i n g of the c y l i n d e r w a l l . Once again the p i s t o n and p i s t o n b l o c k were sent back to Canadian Car. T h i s time a B a b b i t t p i s t o n was made to s p e c i f i c a t i o n s and the i n s i d e of the p i s t o n b l o c k was lapped as before except t h a t an approximately 1 4 - i n . long C.I. p i p e , machined on the s u r f a c e , was used i n s t e a d of the brass c y l i n d e r . B a b b i t t metal i s a white a n t i f r i c t i o n a l l o y composed of copper, antimony,, and v a r y i n g p r o p o r t i o n s of t i n . Upon being set up a f o u r t h time the sampler was found to l e a k 1 9 F i g u r e 1 2 . S c o r i n g on C y l i n d e r Wall 20 at approximately 20 mis./min. At t h i s p o i n t the p r o j e c t appeared to he im p o s s i b l e but ,one more attempt was made t o reduce the leakage. The f i f t h attempt c o n s i s t e d of r e s o l d e r i n g the o r i g i n a l p i s t o n made i n the department shop (as d e s c r i b e d e a r l i e r ) and t r y i n g i t i n the chromed and lapped p i s t o n b l o c k . T h i s time dimensions were such t h a t no leakage occurred when the p i s t o n was over to the r i g h t i n the b l o c k . When the p i s t o n was shoved t o the l e f t i n the b l o c k a leakage r a t e of one to two mis./min. was encountered a f t e r a few seconds. The p i s t o n , however, moved ve r y e a s i l y i n the b l o c k , and i t was p o s s i b l e t o sample o n l y from one s i d e i n order t o keep the leakage at a minimum. Sampling was accomplished by shoving the p i s t o n from i t s r i g h t to l e f t hand p o s i t i o n i n the b l o c k . F o l l o w i n g sampling i t was r e t u r n e d t o the r i g h t hand p o s i t i o n i n which no leakage occurred. I n t h i s way steady s t a t e o p e r a t i o n of the column c o u l d be maintained. As much data as p o s s i b l e were obtained w i t h the equipment o p e r a t i n g i n t h i s manner. C o l l e c t i o n Funnels F i g u r e 14 i s a drawing of a c o l l e c t i o n f u n n e l , which f i t s i n t o the o u t s i d e of each of the two hol e s on the underside of the p i s t o n b l o c k . The fu n n e l s are f i t t e d snugly i n t o the countersunk p o r t i o n of the holes and are 21 h e l d t i g h t by a f l a n g e arrangement t o p r e v e n t l e a k a g e . See F i g u r e 1J. The components o f the c o l l e c t i o n f u n n e l and the assembled f u n n e l are shown i n F i g u r e 15• 22 Section A - A Material: Stainless Steel To Fit § -16 Female Ground Glass Joint F I G U R E 14. C O L L E C T I O N F U N N E L 23 T i l F i g u r e 15• Assemblage o f Components of Funnel The neck of the f u n n e l i s t a p e r e d to f i t the female p o r t i o n of a § - 1 6 ground g l a s s j o i n t . C o l l e c t i o n F l a s k F i g u r e 16 i s a photograph of the c o l l e c t i o n f l a s k shown i n p o s i t i o n on the bottom of a c o l l e c t i o n f u n n e l . The f l a s k was c a l i b r a t e d as t o the t o t a l volume and the neck was c a l i b r a t e d by Cave and Co. L t d . i n one ml. and 0.1 ml. d i v i s i o n s as shown i n F i g u r e 17. The f l a s k was d e s i g n e d so t h a t the t o t a l volume of the p i s t o n sample would f a l l j u s t below the top c a l i b r a t i o n mark whereas the volume of ketone expected i n the sample would se p a r a t e i n the graduated p o r t i o n 2 4 o f the neck. The top c a l i b r a t i o n mark i n d i c a t e d a volume o f 1 1 7 . 0 mis. The neck was c a l i b r a t e d over a 15 ml. range. The neck o f the f u n n e l was f i t t e d w i t h a female p o r t i o n of a §-16 ground g l a s s j o i n t , matching the t a p e r o f the neck o f the c o l l e c t i o n f u n n e l s . S u p p o r t i n g hooks were l o c a t e d on the expanded s e c t i o n of the f l a s k . Wire t e n s i o n s p r i n g s were used to h o l d the f l a s k i n p o s i t i o n on the f u n n e l as shown i n F i g u r e 18. The f l a s k was c a l i b r a t e d by Cave & Co. The c a l i b r a t i o n s were checked by the w r i t e r at a t o t a l o f 13 p o i n t s over the 117 ml. range. P Y R E X 117 ml. 2 0 ° C F I G U R E 17. C O L L E C T I O N F L A S K F i g u r e 18. F l a s k Held i n P o s i t i o n by T e n s i o n S p r i n g s t o P i s t o n B l o c k Column Support F i g u r e 20 i s a drawing of the column support t o which the v a r i o u s s e c t i o n s of the e x t r a c t i o n column are a t t a c h e d . F i g u r e 19 i s a photograph of the support i n an e a r l y stage of i t s c o n s t r u c t i o n . T h i r t y - s e v e n i n c h l e n g t h s of 1 x 1 x 1/8-in. angle i r o n were used to brace the t h r e e m i l d s t e e l p i p e s t o g e t h e r . 27 Figure 1 9 . Column Support i n E a r l y Stages of C o n s t r u c t i o n F i g u r e 21 i s a photograph of the b r a c i n g p a t t e r n which may not be c l e a r i n Fig u r e 2 0 . A 15 f o o t l e n g t h of 2 x 2 x % ~ l n . angle i r o n was welded to each of two of the pipes as shown i n Figu r e 2 1 . The pipes were then set u p r i g h t and welded to a i n . t h i c k i r o n p l a t e which i n t u r n was b o l t e d to the f l o o r . F i g u r e 22 i s a photograph of the assembled, column and a l s o shows how the support was f i x e d t o one of the beams i n the u n i t operations l a b r o a t o r y . FIGURE 20. COLUMN SUPPORT Figure 21. B r a c i n g P a t t e r n of Column Support F i g u r e 22. Assembled Column 30 E l g i n Head and C o n i c a l Section'Supports F i g u r e s 23 and 24 are drawings of the E l g i n head support and the c o n i c a l s e c t i o n supports, r e s p e c t i v e l y . These supports can be clamped to the column support at any d e s i r e d h e i g h t . Eigure 25 i s a photograph of the E l g i n head and i t s support, whereas Eigure 26 i s a photograph of the c o n i c a l s e c t i o n and i t s support. Both supports are clamped to the column support by means of 3^-in. A l l e n head se t screws set a g a i n s t nA~in. t h i c k m i l d s t e e l pressure p l a t e s . T h i s method of clamping i s shown i n F i g u r e 27. F i g u r e 25 a l s o shows the column i n t e r f a c e c o n t r o l l e r which i s b o l t e d to one s i d e of the E l g i n head support. FIGURE 23 . ELGIN HEAD SUPPORT All other dimensions as in FIGURE 23. F I G U R E 24. CONICAL S E C T I O N S U P P O R T F i g u r e 25 . E l g i n Head and I t s Support F i g u r e 2 6 . C o n i c a l S e c t i o n and I t s Support F i g u r e 27» Clamping Arrangement P i s t o n Sampler Support F i g u r e 28 i s a drawing of the p i s t o n sampler support. The p i s t o n b l o c k i s b o l t e d to the support by 4, )£-in. machine screws. One s i d e of the support i s welded to the back of the support. A s i m i l a r s i d e , which c o u l d be b o l t e d to the r i g h t s i d e of the back of the support, was f a b r i c a t e d but no use of i t was ever made. Therefore t h i s item has been omitted on F i g u r e 28. F i g u r e 29 i s a photograph showing how the p i s t o n sampler support was clamped to the column support. AdJListaole c o l l a r s 1o l imit , , p is ton t r a v e l e a c h M x e d to h a n d l e by 2, j — 2 0 A l l e n h e a d s e t s c r e w s . I" 2 Smali key to prevent D ^ t o n from r e l a t i n g p i 31 o n block. F I G U R E 28. S A M P L E R S U P P O R T VJ1 F i g u r e 2 9 . Clamping Arrangement f o r P i s t o n Sampler Support Procedure As t h i s work i s a c o n t i n u a t i o n of Choudhury's work ( 1 ) , i n the sense of j u s t i f y i n g h i s sampling t e c h n i q u e , r e f e r e n c e s should be made to h i s t h e s i s f o r a d e t a i l e d c o n s i d e r a t i o n of the f o l l o w i n g p o i n t s : (a) The steady s t a t e o p e r a t i o n of the e x t r a c t i o n column, i n c l u d i n g i n t e r f a c e adjustments, p e r i o d i c r o tameter r e a d i n g s , e t c . ( l j ) . (b) The a n a l y s i s and h a n d l i n g o f a l l samples t a k e n throughout the course of the experiment ( l k ) . (c) The method of sampling w i t h the probes, i n c l u d i n g p u r g i n g ( l b ) . 37 (d) The c o r r e c t i o n of the measured c o n c e n t r a t i o n of a c e t i c a c i d i n the ketone probe samples because of a p p r e c i a b l e water entrainment ( l k ) . (e) The achievement of mutual s a t u r a t i o n (11). ( f ) The d e s c r i p t i o n and source of a l l reagents ( l m ) . The methyl i s o b u t y l ketone used throughout the experimental work was t e c h n i c a l grade and was made up of v a r i o u s batches from d i f f e r e n t companies. The f o l l o w i n g r e f r a c t i v e i n d i c e s were obtained: Source of MIBK R e f r a c t i v e Index Temperature G.C. Henderson Co. L t d . Order No.l 1.3951 20.1°C Order No.2 1.394-9 20.2°C Canadian Chemical Co. Drum No.2 1.3948 20.2°C (No sample from Drum No. 1 was a v a i l a b l e f o r t e s t i n g although some ketone from t h i s drum was used i n the research) MIBK as p u r i f i e d and pl a c e d i n aluminum tanks at time these were commissioned (1) 1.3947 20.1°C The r e f r a c t i v e index of 99% pure MIBK i s 1.3958 at 20°C(1). 1 - e l l . 38 With, these p o i n t s c o v e r e d * i n - d e t a i l i n Choudhury 1 s work the o p e r a t i n g procedure can "be e x p l a i n e d very b r i e f l y . The l i n e a r v e l o c i t y of ketone through the nozzle t i p s i n a l l cases was 0.36 f t . / s e c , w h i l e the d i r e c t i o n of t r a n s f e r was always from the aqueous phase to the ketone phase. Nozzle t i p p a t t e r n s corresponding t o the v a r i o u s ketone f l o w r a t e s may be found i n F i g u r e 30. Those f o r Lk = 36.5 and 72.9 were a l s o used by Choudhury. The r e q u i r e d f l o w r a t e s were set by means of the rotameters and a s u f f i c i e n t amount of time was allowed f o r the tower to change i t s contents three to f o u r times ( l m ) . During t h i s time the i n t e r f a c e c o n t r o l l e r was a d j u s t e d to h o l d the i n t e r f a c e at one p a r t i c u l a r l e v e l . Throughout a l l the runs the i n t e r f a c e remained three to f o u r inches below the top of the top p l a t e of the E l g i n head. During each run the i n t e r f a c e e l e v a t i o n remained steady but v a r i e d over a one i n c h range from run to run. Thus the height of the column ( n o z z l e t i p s t o i n t e r f a c e ) i s r e p o r t e d as 7 - f t . 3"#-in. - 1/2-in. f o r a l l runs. Throughout the course of a run, numerous checks were made on the i n t e r f a c e h e i g h t and on the flow meter s e t t i n g s . I t was found t h a t l i t t l e or no readjustment was necessary. • B L O C K E D O U T FIGURE 3 0 . T I P P A T T E R N S FOR K E T O N E N O Z Z L E 40 l u n s 71 t o 73? and 76 t o 78 were made t o j u s t i f y the syringe method of sampling the water phase and to check whether or not a c o n c e n t r a t i o n g r a d i e n t e x i s t e d i n a p a r t i c u l a r c r o s s - s e c t i o n i n the column at r i g h t angles to the a x i s of the column and at a p a r t i c u l a r h e i g ht above the noz z l e t i p s . When steady s t a t e c o n d i t i o n s were assumed to p r e v a i l i n the tower hypodermic s y r i n g e samples were taken at d e f i n i t e p o s i t i o n s i n the c r o s s - s e c t i o n . The needle of the syringe entered the column through the asbestos gaskets at c e r t a i n f l a n g e s i n the apparatus. A f t e r a s y r i n g e sample had been taken the s y r i n g e was washed w i t h d i s t i l l e d water and then d r i e d . Before another s y r i n g e sample was taken, 15 c.c. of water phase were withdrawn at the next sampling p o s i t i o n and used to r i n s e the s y r i n g e . Then a 30 c.c. sample of the water phase was removed at t h a t p o s i t i o n and the washing, d r y i n g , and r i n s i n g procedure repeated p r i o r to sampling at the next p o s i t i o n . In Runs 74 and 75 syringe samples were taken at one p o s i t i o n i n a c r o s s - s e c t i o n at v a r i o u s time i n t e r v a l s a f t e r the s t a r t - u p of a run and continued w e l l i n t o the steady s t a t e p e r i o d of o p e r a t i o n of the column. The o b j e c t was t o determine whether or not the syringe samples, taken d u r i n g the steady s t a t e p e r i o d at t h i s one p o i n t , would show any v a r i a t i o n i n the measured c o n c e n t r a t i o n of a c e t i c a c i d . * The hypodermic needles used f o r sampling were standard Yale B-D 19 w i t h the p o i n t of the needle f i l e d o f f so that the needle end l a y i n a p l a i n at r i g h t angles to the needle a x i s . 41 When the p i s t o n sampler was i n c o r p o r a t e d i n t o the apparatus the procedure was s l i g h t l y d i f f e r e n t . When steady s t a t e c o n d i t i o n s were assumed to p r e v a i l i n the tower the probes were lowered t o the e l e v a t i o n of the a x i s of the p i s t o n where purg i n g and sampling of both phases took p l a c e simultaneously.' Purging and sampling r a t e s and pu r g i n g times are r e p o r t e d l a t e r i n t h i s t h e s i s . I n l e t and o u t l e t samples of both phases were taken when the probe samples were b e i n g taken. When s u f f i c i e n t volumes of both phases had been obtained, the probes were removed from the path of the p i s t o n . Water phase samples were taken immediately above and below the p i s t o n b l o c k by means of the hypodermic s y r i n g e , the needle of which entered the column through the asbestos gaskets s e a l i n g the g l a s s column to the p i s t o n b l o c k . The s y r i n g e was washed, d r i e d , and r i n s e d i n a manner d e s c r i b e d e a r l i e r a f t e r each s y r i n g e sample was taken. The l>&-in. I.D. hole i n the p i s t o n t h a t was t o s l i d e i n t o l i n e w i t h the column was f i l l e d w i t h e i t h e r water phase which had leaked from the p i s t o n or w i t h o u t l e t water phase from the column i f there was no such leakage. I n t h i s way when a p i s t o n sample was taken the column continued t o operate w i t h no a p p r e c i a b l e d i s t u r b a n c e . I t was i n t e r e s t i n g t o observe t h a t when a p i s t o n sample was taken a gap i n the ketone phase occurred, which appeared to move up the column. This d i s c o n t i n u i t y i n the ketone phase, however, disappeared a f t e r i t had " r i s e n " one t o two f e e t . 42 The c o l l e c t i o n f l a s k was connected to the f u n n e l which was t o r e c e i v e the p i s t o n sample. When the p i s t o n was slammed from one p o s i t i o n to the o t h e r , the removed s e c t i o n of the column would q u i c k l y empty i t s contents i n t o the c o l l e c t i o n f l a s k . The c o l l e c t i o n f l a s k had to be removed q u i c k l y from the r e c e i v i n g f u n n e l because i n a few seconds water phase would s t a r t t o l e a k i n t o the f l a s k . A f t e r a p i s t o n sample had been taken s u f f i c i e n t time was allowed to change the contents of the column at l e a s t t w i ce to assure steady s t a t e c o n d i t i o n s again. The sampling procedure was then repeated w i t h the p i s t o n being moved i n the opposite d i r e c t i o n . In Run Nos. 82 t o 85 sampling took p l a c e o n l y from r i g h t t o l e f t , s i n c e no leakage occurred when the p i s t o n was over t o the r i g h t i n the p i s t o n b l o c k . A f t e r a sample had been taken the p i s t o n was immediately r e t u r n e d to the r i g h t - hand p o s i t i o n and the sampling procedure repeated from r i g h t to l e f t a f t e r s u f f i c i e n t time had passed f o r steady s t a t e t o be r e - e s t a b l i s h e d . During Run No. 80, an a p p r e c i a b l e volume of ketone phase was e n t r a i n e d i n the continuous phase samples taken by the s y r i n g e s i n the gaskets immediately above and below the p i s t o n b l o c k . This volume was l a r g e enough so t h a t an ap p r e c i a b l e t r a n s f e r of a c e t i c a c i d took plaee out of the water p a r t of the sample and i n t o the ketone p a r t a f t e r a 43 sample was taken. At t h i s p o i n t i n the work the s y r i n g e samples were d i s c o n t i n u e d because of the near i m p o s s i b i l i t y of c o r r e c t i n g f o r such t r a n s f e r i n the circumstances o b t a i n i n g . I t was decided t h a t the water phase probe sample, which showed no ketone entrainment, could be used i n p l a c e of the s y r i n g e samples, i f i t was assumed t h a t the probe sample gave a r e p r e s e n t a t i v e sample of the water phase. This sample o r d i n a r i l y was taken on the a x i s of the p i s t o n . The two phases of the p i s t o n samples were allowed to separate and t h e i r volumes were measured. P a r t of the water phase was drawn from the f l a s k and the remaining contents dropped i n t o a sample b o t t l e . Any ketone which remained i n the f l a s k was then washed i n t o the sample b o t t l e w i t h the water phase p o r t i o n which had been drawn from the f l a s k e a r l i e r . The sample b o t t l e s c o n t a i n i n g p i s t o n samples were shaken v i g o r o u s l y from time to time over a three t o f o u r hour p e r i o d p r i o r to a n a l y s i s . A f t e r t h i s time, and because of the s m a l l volume of ketone, i t was assumed t h a t the two phases were i n e q u i l i b r i u m . During storage the f l a s k s were sealed w i t h icorks covered w i t h aluminum f o i l . The samples were then analyzed f o r t h e i r a c e t i c a c i d content by t i t r a t i o n w i t h sodium hydroxide s o l u t i o n ( l k ) . 44 An attempt was made to analyze the c o n c e n t r a t i o n s of the water phase samples by measurement of t h e i r r e s i s t a n c e s w i t h the s a l i n o m e t e r of the P a c i f i c Oceanographic Group, F i s h e r i e s Research Board of Canada, at Nanaimo, B.C. D e t a i l s of c o n s t r u c t i o n , o p e r a t i o n and maintenance of the s a l i n o m e t e r may be found elsewhere (11). The b r i d g e was s p e c i f i c a l l y designed f o r the d e t e r m i n a t i o n of the s a l i n i t y of sea water by measurement of i t s e l e c t r i c a l c o n d u c t i v i t y . Paquette (12) a d v i s e s t h a t the bridge would undoubtedly work f o r a c e t i c a c i d s o l u t i o n and would y i e l d conductance or r e s i s t a n c e r a t i o s i f used i n the proper way. The r a t i o s are the u s u a l Wheatstone br i d g e r e s i s t a n c e r a t i o s w i t h r e s p e c t to a r e f e r e n c e s o l u t i o n . A s i m p l i f i e d schematic diagram of the c i r c u i t of the salinometer i s shown i n F i g u r e 31. The bridge d e s i g n avoids the n e c e s s i t y of p r e c i s e temperature c o n t r o l i n the c o n d u c t i v i t y c e l l by u s i n g as the adjacent r e s i s t o r i n the W/heatstone b r i d g e a second, n e a r l y i d e n t i c a l , c o n d u c t i v i t y c e l l (Y i n F i g u r e 31) in. the same constant temperature bath, and f i l l e d w i t h r e f e r e n c e s o l u t i o n o f approximately the same c o n c e n t r a t i o n as the sample to be analyzed ( C e l l X ) . In use, the unknown s o l u t i o n i s p l a c e d i n C e l l X and the r e f e r e n c e s o l u t i o n , i n the present case a s o l u t i o n of' c o n c e n t r a t i o n Cv^, i s p l a c e d i n C e l l Y. Arm Ry i s s e t at a value c h a r a c t e r i s t i c of the p a r t i c u l a r c e l l i n use and the c o n c e n t r a t i o n of s o l u t i o n i n the r e f e r e n c e c e l l (700 ohms i n the present c a s e ) . The b r i d g e i s then brought to balance w i t h 45 PHASING CAPACITANCE O S C I L L A T O R FIGURE 31. SIMPLIFIED BRIDGE CIRCUIT Table I I C a l i b r a t i o n of Salinometer S a m p l e C o n c e n t r a t i o n of A c e t i c A c i d i n R e s i s t a n c e Made-up Water Phase S a m p l e o f C e l l X 2 l b . m o l e s / f t . x 10^ ohms wl 50.2 694 .15 * ^w2 32 .5 739.44 1 36.2 728.04 2 36.9 718.68 3 4-3.4 710.24 4 46 .7 702.44 Samples obtained by making up v a r i o u s volumes of i n l e t and o u t l e t water phase s o l u t i o n from Run 84. Concentrations of these samples were obtained by t i t r a t i o n . I n l e t water phase s o l u t i o n from Run 84 was used as ref e r e n c e s o l u t i o n i n C e l l Y. I t s c o n c e n t r a t i o n was determined by t i t r a t i o n . Samples designated by the symbol f o r t h e i r c o n c e n t r a t i o n . 47 R E F E R E N C E C E L L X C O N T A I N S I N L E T W A T E R P H A S E F R O M R U N 8 4 . R E F E R E N C E D I A L S E T AT 7 0 0 0 0 T E M P E R A T U R E OF B A T H AT 5 ° C 7 3 0 7 2 6 <0 o 718k 714 ,710 7 0 6 f - 7 0 2 r - 698r- 6 9 4 h 3 6 3 8 • 4 0 C O N C E N T R A T I O N 4 2 4 4 OF A C E T I C AC|D 4 6 4 8 50 lb. moles, 10 - F I G U R E - 3 2 . S A L I N O M E T E R C A L I B R A T I O N C l J R V F 48 Ex. Rx i s now a s i n g l e - v a l u e d n e a r l y l i n e a r f u n c t i o n of the a c e t i c a c i d c o n c e n t r a t i o n of the water phase. A number of water phase c a l i b r a t i o n samples were prepared by m i x i n g v a r i o u s volumes of i n l e t and o u t l e t water phase taken from Run 84. P i s t o n samples from Run 84 were allowed to stand f o r 24 hours before the two phases were separated and analyzed by t i t r a t i o n . The remaining water phase p o r t i o n s were p l a c e d i n 125 ml. f l a s k s and s e a l e d w i t h t i n f o i l - c o v e r e d corks. The f l a s k s were kept at 2°C f o r 5 days before t a k i n g them to Nanaimo to measure t h e i r r e s i s t a n c e s . The c a l i b r a t i o n samples were se a l e d and s t o r e d i n a s i m i l a r manner f o r the same p e r i o d and t h e i r r e s i s t a n c e s measured d u r i n g the same v i s i t t o Nanaimo and w i t h the same Ry s e t t i n g as used f o r the p i s t o n samples. The r e s i s t a n c e s of the water phase c a l i b r a t i o n samples, whose c o n c e n t r a t i o n had been determined by t i t r a t i o n , were measured, and the c a l i b r a t i o n curve shown i n F i g u r e 52 was prepared. F i g u r e 32 r e l a t e s the c o n c e n t r a t i o n of the water phase to the r e s i s t a n c e Rx. The c a l i b r a t i o n curve, however, i s s p e c i f i c o n l y f o r Run 84 as column aqueous feed from t h i s run ( c o n c e n t r a t i o n Cw^) was used i n the Reference C e l l Y of the salinometer f o r the p a r t i c u l a r s e r i e s of measurements r e l a t e d to t h a t run. C e l l X was always washed three times w i t h the water phase s o l u t i o n whose r e s i s t a n c e was t o be measured. The water phase s o l u t i o n was always p i p e t t e d from the bottom See Table I I . of the sample f l a s k to i n s u r e t h a t any ketone, which had f a i l e d to be separated from the water phase p o r t i o n , would not be taken up i n t o the p i p e t t e . The p i p e t t e a l s o r e c e i v e d three thorough washings w i t h the s o l u t i o n whose r e s i s t a n c e was to be measured. P r e v i o u s experience i n measuring the r e s i s t a n c e of the water phase s o l u t i o n w i t h the s a l i n o m e t e r showed t h a t the presence of two phases i n C e l l X would a f f e c t the r e s i s t a n c e readings c o n s i d e r a b l y . Thus i t was necessary to withdraw the water phase p o r t i o n c a r e f u l l y w i t h a p i p e t t e i f any minor ketone l a y e r was present. The f i v e p i s t o n samples from Run 84- were analyzed f o r a c e t i c a c i d u s i n g the sali n o m e t e r i n c o n j u n c t i o n w i t h the c a l i b r a t i o n curve. The r e s u l t s were compared w i t h the val u e s obtained by t i t r a t i o n . U n f o r t u n a t e l y the r e s u l t s d i d not agree and the method was not used f u r t h e r i n the present r e s e a r c h . CALCULATIONS The r a t e of t r a n s f e r of a c e t i c a c i d across the i n t e r f a c e i n the column was c a l c u l a t e d i n l b . moles/hr. by two d i f f e r e n t equations. One was based on the t o t a l change i n c o n c e n t r a t i o n of the water phase, and the other was based on the corresponding t o t a l change i n c o n c e n t r a t i o n of the ketone phase. These equations were 50 N H = LwA(Cw 1 - Cw 2) 1 Nk = LkACCk^ - Ck 2) 2 Values of Nvr and Nk v a r i e d s l i g h t l y and an average value was determined by N = Nw + Nk 3 2 The percentage d e v i a t i o n was c a l c u l a t e d f o r each run as a measure of the q u a l i t y of the experimental work. The equation used was Percentage D e v i a t i o n = ^ N k ) 1 0 0 4 An a c e t i c a e i d balance equation was w r i t t e n between the i n i t i a l c o n d i t i o n s e x i s t i n g i n the column at the time of sampling i n the f o u r i n c h h i g h p i s t o n s e c t i o n , and the f i n a l e q u i l i b r i u m c o n d i t i o n s e x i s t i n g i n the removed p i s t o n sample. The equation was Ck ± Vk + C.^ Yw = Ck f Vk + Cw f Vw 5 and when used was s o l v e d f o r C k i . F i g u r e 33 i s a s i m p l i f i e d drawing r e p r e s e n t i n g the sampling procedure t o which Equation 5 was a p p l i e d . Steady s t a t e c o n d i t i o n s were assumed t o e x i s t i n the e x t r a c t i o n column p r i o r t o sampling and any volume changes a f t e r sampling have been n e g l e c t e d . Volume changes w i t h r e s p e c t to the i n l e t and o u t l e t streams, have also: be ere neglected. R E M O V E D P I S T O N SAMPLE Ketone P h o s e Volume = V^ Concentration = CKf in Equilibrium With the Water Phase Water Volume = Concentration 'wp •kp Average Initial C o n c e n t r a t i o n s in 4" P i s t o n Section are and C, Kl FIGURE 33. SIMPLIFIED DRAWING OF SAMPLING P R O C E D U R E 52 Volume changes might be expected as a r e s u l t of a c e t i c a c i d t r a n s f e r and changes i n the mutual s o l u b i l i t y of ketone and water accompanying the t r a n s f e r of a c e t i c a c i d . A sample c a l c u l a t i o n to show why these volume changes have been n e g l e c t e d i s i n c l u d e d i n the Appendix. The water phase c o n c e n t r a t i o n p r o f i l e i s assumed to be l i n e a r over the s i x i n c h l e n g t h of column between CW^^ and CwO-g. T h i s assumption was a r r i v e d at by examination of water phase c o n c e n t r a t i o n p r o f i l e s from Choudhury's work ( 1 ) . I n h i s work the water phase c o n c e n t r a t i o n p r o f i l e s which showed the g r e a t e s t curvature over a seven f o o t l e n g t h of column c o u l d be assumed to be l i n e a r over a s i x i n c h l e n g t h of column at any p o i n t on the p r o f i l e . I n some runs, i n the present work Cw^ was found before t a k i n g a p i s t o n sample by withdrawing water phase samples Cw^^ and Cw^g, w i t h a hypodermic syringe at the t o p , ),£, and at the bottom, ) B , of the p i s t o n b l o c k . Thus i f a l i n e a r p r o f i l e can be assumed t o e x i s t between Cw^),j, and Cw^)^, Cw.^  can be approximated by Cw ± = C w ± ) T + C w i ) B 6  2  I n other runs Cw^ was obtained by t a k i n g a sample w i t h the water phase probe at the e l e v a t i o n of the a x i s of the p i s t o n samples. Vk and Vw were obtained from the c a l i b r a t i o n s on the c o l l e c t i o n f l a s k , whereas Cwf was obtained by a n a l y s i s of the water phase p o r t i o n of the p i s t o n sample a f t e r 53 equilibrium bad been reached with the ketone phase po r t i o n . Ckf was obtained from the equilibrium r e l a t i o n s h i p since volume Vk i s i n s u f f i c i e n t f o r analysis at low ketone phase holdups. At higher holdups, (see Run 84, Table VIII,' and Run 85, Table IX), a s u f f i c i e n t amount was present f o r one analy s i s . Combining Equations 5 and 6 and rearranging to solve f o r Ck^ gives Ck, = £g x Vw Vk Cwf - Cw.^-j + Ck f As mentioned e a r l i e r the taking of samples represented i n Equation 7 by Cw^)j- and Cw^)g had to be discontinued. When the probe sample taken on the axis of the pi s t o n sampler i s used instead, on the assumption that Cw = Cw., Equation 7 becomes C k i = vf * ( C w f " C V + C k f 8 In Run 85, the major portion of the water phase was separated from the ketone phase immediately a f t e r taking the piston samples. The ketone phase and the small remaining volume of water phase were allowed to come to equilibrium before some of the ketone phase was withdrawn f o r a n a l y s i s . The o r i g i n a l concentration of the ketone drops i n the column could be cal c u l a t e d by the following material balance equation Ck. = Cw. Vw + Cw- Vw + Ck. - Cw_ Vw 9 1 1 V k 1 Vk 1 p V k 5 4 The ketone phase holdup was c a l c u l a t e d from the measured volumes of the ketone and water phases of the p i s t o n samples by the f o l l o w i n g equation H " <Vk ! kYw ) 1 0 0 % 1 0 The maximum e r r o r s t h a t c o u l d be expected i n the p i s t o n samples were c a l c u l a t e d by the method set out by Bl i c k l e y , Sherwood and Reed ( 1 0 ) . B r i e f l y , the method i s t o r e l a t e the e r r o r of the c a l c u l a t e d q u a n t i t y to the e r r o r s of the measured q u a n t i t i e s i n the form of a p a r t i a l d i f f e r e n t i a l equation such as dQ » M ^ i * 2&.dq 2 + — • • •+-2&.<£qn-' 11 i n which the d i f f e r e n t i a l s dq-^, dqg,..., d q n of the measured q u a n t i t i e s are r e p l a c e d by s m a l l f i n i t e increments £»q-£> A q g . . . . * A q n , , and, s i m i l a r l y dQ by AQ. The ex p r e s s i o n takes the form AQ agQAq^ + Aq 2+ .... + A q n .... 12 3qx ^ q 2 3qn The q u a n t i t i e s Aq-p Aq 2» ...» A q n may be consider e d as e r r o r s i i i q^, q^, q n , and AQ i s , to good approximation, the e r r o r i n the c a l c u l a t e d q u a n t i t y , Q. Equation 12 holds f o r any type of e r r o r s , p r o v i d i n g o n l y t h a t they are s m a l l . On the other hand, Equation 12 does not u t i l i z e a l l the 55 i n f o r m a t i o n t h a t may be a v a i l a b l e and consequently o f t e n overestimates the e r r o r i n the c a l c u l a t e d q u a n t i t y . T h i s p o i n t w i l l be d i s c u s s e d l a t e r w i t h the a i d of an example. A p p l y i n g E q u a t i o n 12 to Equa t i o n 5 we get the r e s u l t i n g e x p r e s s i o n A C k t = A'-ACk f + !• AVw + O A v k + D» ACw f + E-&Cw± 13 where A' = ack^ = 2 3Ck^ B = 3Ck. = _1_ . (Cw. - Cw, ) 3Vw Vk 1 1 C = 9Ck. = - VK.(CW~ - Cw. ) gVk 1 1 1 D = 3Ck. = Vw ? f 3Cwi Vk E = 3Ck. = Vw 3Cw^ Vk Estimated v a l u e s of AVw, AVk, ACw f, ACw^ and A Ck^ have been used t o c a l c u l a t e v a l u e s of ACk^. These valu e s were - 0.2 mis. f o r the volume v a r i a t i o n and . "5 3 - 0.1 x 10 l b . moles a c e t i c a c i d / f t . f o r a l l three c o n c e n t r a t i o n v a r i a t i o n s . 5 6 An a c e t i c a c i d m a t e r i a l "balance was c a l c u l a t e d f o r the o v e r a l l o p e r a t i o n of the e x t r a c t i o n column as an a d d i t i o n a l check on the q u a l i t y of the experimental work. The ex p r e s s i o n was Percentage D i f f e r e n c e = A c i d I n - A c i d Out IOQ% A c i d In ( LyACw^+LkACk^ )- (LwACw^+LkACk-^ ) LwACw-^  + LkACk 2 14 A complete d e s c r i p t i o n of a l l the symbols used i n Equations 1 to 14 may be found i n the Nomenclature. Sample c a l c u l a t i o n s u s i n g these equations may be found i n the Appendix. RESULTS Tables I I I t o X I i n c l u s i v e present a l l the data obtained i n the o p e r a t i o n of the e x t r a c t i o n column and the v a r i o u s sampling d e v i c e s . Table I I I g i v e s the sampling r a t e s and purging times which were used when sampling was t a k i n g p l a c e w i t h the water phase and ketone phase probes. In some cases the p u r g i n g time does not correspond to the minimum purging time t o o b t a i n u n i f o r m c o n c e n t r a t i o n s g i v e n by Choudhury ( l n ) . 57 Table IV g i v e s the o v e r a l l t r a n s f e r data f o r each run. Tables V and V I I show the c o n c e n t r a t i o n data which were obtained by sampling the water phase w i t h the hypodermic s y r i n g e at v a r i o u s p o s i t i o n s i n column c r o s s - s e c t i o n s each of a d e f i n i t e e l e v a t i o n above the n o z z l e t i p s . The p o s i t i o n s i n the column c r o s s - s e c t i o n s at which the hypodermic s y r i n g e samples were c o l l e c t e d may be seen i n F i g u r e 34. Table VI g i v e s the c o n c e n t r a t i o n of the water phase at P o s i t i o n 6 as a f u n c t i o n of time a f t e r the s t a r t - u p of a run. Tables V I I I and IX give the ketone phase holdups f o r s i x runs and a l s o compares the c o n c e n t r a t i o n s of the ketone phase ( C k ^ ) , as c a l c u l a t e d by Equations 7 and 8 w i t h the ketone phase c o n c e n t r a t i o n s of the samples which were obtained w i t h the probe (Ck ). Table IX g i v e s the data f o r Run 85 i n which the two phases were separated immediately a f t e r t a k i n g the p i s t o n sample. Table X shows the approximate maximum e r r o r of the c a l c u l a t e d i n i t i a l ketone c o n c e n t r a t i o n (Ck^). Included i n t h i s t a b l e are the e r r o r s due to the i n d i v i d u a l v a r i a b l e s . Table XI shows the comparison of the c o n c e n t r a t i o n s of the p i s t o n samples f o r Run 84 as determined by the salinometer and by the t i t r a t i o n method. The samples used i n c a l i b r a t i n g the salinometer and the p i s t o n samples were handled i n an i d e n t i c a l manner and t h e i r r e s i s t a n c e s measured w i t h respect 58 to the same s o l u t i o n i n the Reference C e l l Y. C a l i b r a t i o n samples were prepared by mixing v a r i o u s volumes of i n l e t and o u t l e t water phases from Run 84-, and t i t r a t i n g the m i x t u r e s . In most cases the r e s u l t s have been reduced to three s i g n i f i c a n t f i g u r e s . However, f o u r s i g n i f i c a n t f i g u r e s were used i n t h e i r c a l c u l a t i o n , as can be seen from the sample c a l c u l a t i o n s i n Appendix 1. Table I I I Sampling Rate and P u r g i n g Time Run Sampling r a t e P urging time Minimum Purge Time No. ml. /min. min. as s p e c i f i e d by, Choudhury ( l n ) , m i n . Water Ketone Water Ketone phase phase phase phase probe probe probe probe 79 6.0 6 .5 10 11 + 2 12 + 2 80 5.0 6.4 15 13 + 2 12 + 2 81 7.4 3.5 15 8 + 2 20 + 2 82 5.2 4 . 7 24 . 13 + 2 16 + 2 83 5.1 5.1 30 13 + 2 15 + 2 84 4 . 8 5.4 10 13 + 2 15 + 2 4 .7 5.2 11 + X 13 + 2 15 + 2 85 5.0 6.6 15 13 + 2 12 + 2 F i r s t probe sample taken before the e i g h t p i s t o n samples, and the second a f t e r . T h i s f i g u r e i s the t o t a l of the sampling and purge times f o r the preceeding probe sample. Between the two probe samples the probes were moved above the a x i s of the p i s t o n w i t h the f l u i d i n the probe tube stagnant, x i s at l e a s t 10 min. Table IV O v e r - A l l T r a n s f e r Data Run I n l e t and O u t l e t C o n c e n t r a t i o n s Flow Rates O v e r a l l A c e t i c A c i d Percentage No. ^ P T r a n s f e r Rates , D e v i a t i o n s F t ? / h r . / f t f l b . moles/hr. x 1CK N -N v xlOO W l b . m o l e s / c u . f t . x 10^ Ketone Water Ketone Water Ketone Average A c e t i c A c i d M a t e r i a l Balance % D i f f e r e n c e Water In Cw-j^  Out Cw 2 In C k 2 Out Ck-j^  Lw \ w \ N 71 — — • 42.5 37.5 7 2 49.9 3 6 . 5 6.9 2 2 . 9 42.5 37-5 7.01 7.36 7.18 -4.87 - 1.19 73 50.2 36.4 6.9 22.7 43.0 36.3 7.29 7.03 7.16 +3.63 +0.89 74 5 0.0 36.1 6.8 22.8 43.0 36.8 7.32 7.28 7.30 + 0 . 5 5 +0.30 75 5 0.2 36.3 6.8 22.6 43.4 36.3 7.36 7.14 7 . 2 5 + 3 . 0 3 +1.10 7 6 50.2 36.6 6.8 22.6 43.0 36.3 7.18 7.02 7.10 +2.30 +0.47 77 50.0 36.7 6.9 22.6 42.9 36.8 7 . 0 3 7.04 7.04 -0.04 - 0.03 78 5 0 . 0 36.8 7.0 22.6 42.8 36.4 6.94 6 . 9 7 6 . 9 6 - 0.43 - 0.10 7 9 49.9 35.7 7.0 23.9 43.0 36.8 7.47 7.65 7.56 -2.38 - 0.54 80 5 0.0 22.2 6.8 21.5 36.5 73.0 12.4 13.1 12.8 -5.16 - 2.34 81 5 0.0 21.7 6.8 21.6 36.5 7 2.9 1 2.7 13.2 13 . 0 - 3.85 - 1 . 7 2 82 5 0.0 3 2.4 6.8 24.7 7 2.2 7 2.9 1 5.6 1 5 . 9 15.8 -1.90 - 0.60 83 5 0.0 3 2.4 6.8 24.8 7 2.2 7 2.5 1 5.6 16.0 15.8 - 2 . 0 9 - 0.66 84 5 0.2 3 2.5 7-1 24.8 90.9 90.5 19.8 19-7 1 9 . 7 +0.20 +0.03 85 5 0.2 , 32.5 7.1 24.8 9 0 . 9 90.5 19.8 19.7 19 . 7 +0.20 +0.03 o 61 Table V Conc e n t r a t i o n P r o f i l e s i n Cr o s s - S e c t i o n s P e r p e n d i c u l a r To The Column A x i s as Determined by Sampling w i t h the Hypodermic Needle C o n c e n t r a t i o n of A c e t i c A c i d l b . m o l e s / f t ^ x 103 P o s i t i o n ( Q A Q Run Number P i g . 34) 71 72 73 7A 75 76 77 78 1 36.2 36.7 47.5 46.8 37.1 37.4 2 36.4 36.8 47.2 3 36.7 34.3 47.4 46.8 36.9 37.2 4 36.5 35-8 46.8 5 36.9 36.7 46.8 46.8 36.9 37.1 6 37-7 46.5 36.4* 36.8* 7 8. 9 37.7 37-0 46.2 46.9 36.7 36.8 46.8 36.7 36.8 10 47.1 36.9 37.0 11 46.9 36.8 37.0 12 46.9 37.0 37.0 13 46.8 36.7 37.0 14 46.8 36.8 37.0 15 46.8 36.4 36.8 16 46.8 35.8 36.9 17 47.0 35.8 36.8 18 47.1 36.4 37.1 19 47.1 36.8 37.4 Average Con c e n t r a t i o n 36.8 36.2 46.9 36.4 36.8 46.9 36.7 37.0 Standard D e v i a t i o n ±0.5 ±0.9 ±0.5 ±0.4 ±0.1 ±0.1 ±0.4 ±0.2 Height above Nozzle T i p s 4" 4" 6' 4#" 1 4" 4#" 6' 4#" 4" 4" Average Ketone Entrainment I n Each 30 ml. Sample,mis. 0.5 o.? 0.? 1.0 0.5 0.5 0.? 0.5 ' r # Average of 6 samples taken at p o s i t i o n 6 as a f u n c t i o n of time a f t e r steady s t a t e had been reached i n the column.See Table V I . 62 Table V I Co n c e n t r a t i o n of Water Phase at P o s i t i o n 6 as a F u n c t i o n of Time A f t e r Start-Up of a Run Sample Time A f t e r C o n c e n t r a t i o n of A c e t i c A c i d i n No. S t a r t - u p Sample Taken by Hypodermic Needle min. at P o s i t i o n 6 l b . m o l e s / f t 3 x K ) 3 Run 74 Run 75 Run 74 Run 75 1 5 :. 33.8 2 15 8 38.2 36.2 3 25 18 3 6 . 8 * 3 6 . 7 * * 4 35 2 8 3 6 . 6 * 3 6 . 7 * * 5 4 9 38 3 5 . 5 * 3 6 . 9 * * 6 59 4 8 3 6 . 4 * 3 6 . 8 * * 7 6 9 58 3 6 . 5 * 3 6 ' 7 * * , 8 79 68 3 6 . 5 * 3 6 . 7 * * * * * Average 36.4 36.8 Samples 3 t o 8 have been averaged to represent the steady s t a t e c o n c e n t r a t i o n of the water phase at p o s i t i o n 6 i n the c r o s s - s e c t i o n . The Standard D e v i a t i o n of these 6 samples i s ± 0.4 x 1 0 ~ 3 . Samples 3 to 8 have been averaged to represent the steady s t a t e c o n c e n t r a t i o n of the water phase at p o s i t i o n 6 i n the c r o s s - s e c t i o n . The Standard D e v i a t i o n of these samples i s ± 0.1 x 1 0 - 3 . 63 Table V I I Hypodermic Syringe Sampling Rates mis./min. Run Number v o c e Fig.3 4 ) 71 72 73 74 75 76 77 78 1 30 7.5 8.5 10 10 10 2 30 12.6 8.6 3 30 12.0 7.0 10 10 10 4 30 12.9 9.4 5 6 30 15 10.3 8.6 8.0 10.0* 10.0* 10 10 10 7 15 10.0 9.1 15 10 10 8 9 15 10 10 10 10 10 10 11 10 10 10 12 10 10 10 13 10 10 10 14 10 10 10 15 10 10 10 16 10 10 10 17 10 10 10 18 10 10 10 19 10 10 10 Average ketone sampling r a t e i n 6 samples taken at P o s i t i o n 6. A C T U A L L O C A T I O N O F S Y R I N G E S A M P L E S F u l l Size F I G U R E 34. P O S I T I O N S IN C O L U M N C R O S S - S E C T I O N A T W H I C H H Y P O D E M I C S Y R I N G E S A M P L E S W E R E T A K E N 65 Table V I I I Concentrations and Comparison of P i s t o n and Probe Samples" Run No. Sample Volumes mis.  Ketone Water Holdup Concentrations of A c e t i c A c i d l b . moles/ft$ x 105 V,. w H C w f °kf C w i Cwp C k p C k i a 79 40.2 41.0 15.0 i 3.8 111 .7 3.4 39.5 20.1 0 .7 i i 3.7 112.0 3.3 39.6 20.2 3.8 i i i 3.5 111 .7 3.1 39.8 20.3 6.5 i v 4 . 0 111.9 3.6 39.2 19.8 -8.2 * 80 25.5 26.8 10.3 i 9.3 106.4 8.0 25.1 12.2 b 9.1 * 81 25.3 26.8 10.8 i 8.2 108 .5 7.0 25.2 12.3 10.1 i i 8.4 106.2 7.3 25.6 12.5 16.2 i i i 8.4 107.5 7.3 * 82 0 40.2 41.4 16.0 i 10.0 105.3 8 .7 39.5 20.1 12.3 i i 9.5 105.5 8.3 39.4 20.0 10.5 83 40.2 40.2 15.6 i 9.6 101.8 8.6 39.4 20.0 11.5 i i 9.4 105.4 8.2 39.5 20.1 12.4 i i i 9.8 105.4 8 .5 39.5 20.1 12.2 i v 9.8 105.0 8 .5 59.6 20.2 14.1 84 f 41.2 41.2 16.3 i 15.6 101.4 11.8 40.3 19.7 12.9 i i 13.1 101.7 11.4 40.3 19.7 12.2 i i i 13.6 101.4 11.8 40 .2 19.6 12.0 i v 13.1 101.6 11.4 40.2 19.6 11.1 V 14.6 100.9 12.7 40.0 19.5 11.0 v i 13.7 101.3 11.9 40.2 19.6 12.1 v i i 13.7 101.3 11.9 40.3 19.7 13.0 v i i i 14.2 101.3 12.3 40.3 19.6 12.7 41.2 16.4 In a l l cases- the a x i s of the p i s t o n was 1.59 f t . above the n o z z l e t i p s . Probes were l o c a t e d one i n c h above p i s t o n a x i s , i . e . one i n c h too h i g h . " . a C a l c u l a t e d by Equation 6 " C w i taken from Run 80 c C w i taken as Cwp from Run 85 d C ^ i taken as Cwp e Owi taken as Cwp f Cfcf c o n c e n t r a t i o n s i n Run 84 obtained by t i t r a t i o n . Ckf c o n c e n t r a t i o n s i n Runs 79,80,81,82,83,were obtained from e q u i l i b r i u m curve. Table IX R e s u l t s of Immediate S e p a r a t i o n of the Two Phases i n the P i s t o n Samples of Run 85 Run Volumes of P i s t o n Samples Holdup C o n c e n t r a t i o n of A c e t i c A c i d No. mis. % l b . m o l e s / f t 3 x 103 5 V w n \ V w V k H ^wp ^wf — n Cwf C k f * C k i % 85 i 100.0 1.0 101.0 13.2 11.6 41 . 2 40 . 1 38.6 19.6 11.2 17.0 i i 100.5 0.6 101.1 13.1 11.5 40 .2 38.5 19.5 11.9 i i i 100.3 0.8 101.1 13.2 11.5 40 .3 38.5 19.5 12.9 i v 100.0 1.2 101.2 13.6 11.9 40 .2 38.3 19.4 12.0 The a x i s of the p i s t o n was 1 . 5 9-ft. above the n o z z l e t i p s . Obtained by t i t r a t i o n . Table X Maximum Approximate E r r o r of C a l c u l a t e d I n i t i a l Ketone C o n c e n t r a t i o n , C P i s t o n Sample Water Phase A c e t i c Volumes A c i d C o n c e n t r a t i o n s mis. of P i s t o n Samples Water Ketone Ketone Water l b . m o l e s / f t ? x 105 Run Plow Rates No. f t $ / h r . / f t ? E r r o r Due to Each V a r i a b l e i n Equa t i o n 14** lb.moles A c e t i c A c i d / f t ^ x 10^ Approx. T o t a l Max. E r r o r w V r V w C. wf wx A'AC k f BAV w CAV,. DAC wf EAC wi AC k i 75i i i i i i i v 80 i 81 i i i 82 i i i 83 i i i i i i i v 84 i i i i i i i v v v i v i i v±Li 43.0 36.8 3 6 . 5 3 6 . 5 7 2 . 2 7 2 . 2 7 3 . 0 7 2 . 9 7 2 . 9 7 2 . 5 9 0 . 9 9 0 . 5 3.8 3 . 7 3 . 5 4.0 9 . 3 8.2 8.4 10.0 9 . 5 9.6 9.4 9.8 9.8 13.6 13.1 13.6 13.1 14.6 13 . 7 1 3 . 7 14.2 1 1 1 . 7 1 1 2 . 0 1 1 1 . 7 1 1 1 . 9 106 . 4 108 . 5 106 . 2 1 0 5 . 3 1 0 5 - 5 1 0 1 . 8 1 0 5 . 4 1 0 5 . 4 1 0 5 . 0 1 0 1 . 4 1 0 1 . 7 1 0 1 . 4 1 0 1 . 6 1 0 0 . 9 1 0 1 . 3 1 0 1 . 3 1 0 1 . 3 3 9 . 5 3 9 . 6 3 9 . 8 3 9 . 2 2 5 . 1 2 5 . 2 2 5 . 6 3 9 . 5 39.4 3 9 . 4 3 9 . 5 3 9 . 5 3 9 . 6 4 0 . 3 4 0 . 3 4 0 . 2 4 0 . 2 40.0 4 0 . 2 4 0 . 3 4 0 . 3 4 0 . 2 2 5 . 3 2 5 . 3 4 0 . 2 4 0 . 2 4 1 . 2 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0 . 1 0.04 0 . 0 3 0 . 0 2 0 . 0 5 0 . 0 0 0 . 0 0 0 . 0 1 0 . 0 1 0 . 0 2 0 . 0 2 0 . 0 1 0 . 0 1 0 . 0 1 0 . 0 1 0 . 0 1 0 . 0 1 0.01 0 . 0 2 0 . 0 1 0 . 0 1 0 . 0 1 1 . 0 7 0 . 9 8 0 . 7 3 1.40 0 . 0 5 0 . 0 3 0 . 0 9 0 . 1 0 0 . 2 2 0.18 0 . 1 7 0 . 1 5 0 . 1 3 0 . 1 0 0 . 1 1 0 . 1 1 0 . 1 2 0 . 1 1 0 . 1 1 0 . 1 0 0 . 0 9 2 . 9 4 3 . 0 3 3 . 1 9 2.80 1.14 1 . 3 2 1.26 1 . 0 5 1 . 1 1 1.06 1 . 1 2 1 . 0 7 1 . 0 7 0 . 7 5 0 . 7 8 0 . 7 5 0 . 7 8 0 . 6 9 0 . 7 4 0 . 7 4 0 . 7 1 2 . 9 4 3 . 0 3 3 . 1 9 2.80 1.14 1.32 1.26 1 . 0 5 1 . 1 1 1.06 1.12 1 . 0 7 1 . 0 7 0 . 7 5 0 . 7 8 0 . 7 5 0 . 7 8 0 . 6 9 0 . 7 4 0 . 7 4 0 . 7 1 7.1 7.2 7.2 7.2 2.4 2.8 2.7 2.2 2.5 2.3 2.5 2.4 2.3 1.7 1.8 1.7 1.8 1.6 1.7 1.7 1.6 Water phase a c e t i c a c i d c o n c e n t r a t i o n s of p i s t o n samples taken from Table V I I I ^ See sample c a l c u l a t i o n i n Appendix 68 Table X I Comparison of Two Methods of A n a l y s i s Samples from Run 84 Salinometer Readings C o n c e n t r a t i o n of A c e t i c A c i d i n Water Phase P i s t o n Samples ohms l b . m o l e s / f t ? x l b 5 R x By Salinometer By T i t r a t i o n C a l i b r a t i o n (See P i g . 32) i 728.99 35.9 40.3 i i 729.13 35.8 40.3 i i i 728.04 36.2 40.2 i v 726.74 35.7 40.2 V 727 .15 36.5 40.0 C ^ wp 718.35 40.0 41.2 Lower case Roman numerals are p i s t o n samples from Run 84. 69 DISCUSSION Operating C o n d i t i o n s The o v e r - a l l mass t r a n s f e r r e s u l t s f o r runs of the same o p e r a t i n g c o n d i t i o n s were found to be f a i r l y r e p r o d u c i b l e as shown i n Table IV. The maximum e r r o r to be expected i n the mass t r a n s f e r r a t e (Nw or Nk) was c a l c u l a t e d from an equation s i m i l a r to Equation 12 w i t h the independent v a r i a b l e s taken as f l o w r a t e and c o n c e n t r a t i o n . This maximum percentage e r r o r was - 3% and occurs i n runs w i t h the s m a l l e s t t r a n s f e r r a t e . T h i s r e s u l t was based on a - 0.004 c u . f t . / h r . f l u c t u a t i o n i n the + -3 / 3 r e p o r t e d f l o w r a t e , and a - 0.1x10 y l b . m o l e s / f t . e r r o r i n the a n a l y s i s f o r a c e t i c a c i d . At t h i s p o i n t i t should be mentioned t h a t the author attempted to t i t r a t e a l l the samples t o what appeared to be the same p i n k i s h c o l o r which represented the end-point i n the a c i d - base t i t r a t i o n . A t i t r a t i o n of a ketone phase blank s o l u t i o n showed t h a t one drop of base turned the c o l o r of the blank c o n s i d e r a b l y darker than t h a t reached at the end-point of the samples. The blank c o n s i s t e d of 5 mis. of ketone, 30 t o 40 mis. of e t h a n o l , and 3 drops of p h e n o l p h t h a l e i n , which was s i m i l a r to a t i t r a t e d sample. As a r e s u l t no blank t i t r a t i o n c o r r e c t i o n was a p p l i e d to the measured c o n c e n t r a t i o n s of the ketone samples. A s i m i l a r blank was prepared f o r the water phase samples and again no blank c o r r e c t i o n was needed. 70 In t i t r a t i n g the water phase samples some d i f f i c u l t y was obtained i n reaching the end-point because of the author's i n a b i l i t y to d i s t i n g u i s h the f i r s t stages of pink from the c o l o r l e s s s o l u t i o n of the i n i t i a l sample. As a r e s u l t , the t i t r a t i o n of 10 samples of the same water phase s o l u t i o n y i e l d e d c o n c e n t r a t i o n s which had a standard d e v i a t i o n of - 0 .1x10 ^ l b . m o l e s / f t . This would be e q u i v a l e n t to approximately - 2 drops of the sodium hydroxide s o l u t i o n . The ketone phase was much e a s i e r to t i t r a t e because of the much more d i s t i n c t c o l o r changes. As the end-point of the ketone phase was approached, and, i n f a c t , as one drop of sodium hydroxide was added the c o l o r of the s o l u t i o n would t u r n a d i s t i n c t y e l l o w . One more drop of base would cause the c o l o r to change t o a d i s t i n c t p i n k . T i t r a t i o n of 10 ketone phase samples of the same c o n c e n t r a t i o n showed no v a r i a t i o n i n the volume of base r e q u i r e d to reach each end-point. However, a i O . l x l O - ^ l b . m o l e s / f t ? v a r i a t i o n i n the c o n c e n t r a t i o n of the ketone phase was a l s o a p p l i e d i n determining the e r r o r s i n v o l v e d i n the v a r i o u s measured q u a n t i t i e s f o r c a l c u l a t i o n of the maximum e r r o r to be expected i n the mass t r a n s f e r r a t e s (Nw or Nk) and i n the c a l c u l a t e d i n i t i a l ketone c o n c e n t r a t i o n ( C k i ) . I t should a l s o be mentioned t h a t the same batch of sodium hydroxide s o l u t i o n was used to t i t r a t e a l l the samples from Runs 73 t o 8 5 . A check on the n o r m a l i t y of the sodium 71 hydroxide s o l u t i o n at the end of a l l the experimental work showed no change i n the n o r m a l i t y of the s o l u t i o n from t h a t which a p p l i e d at the beginning of the experimental work. The t r a n s f e r r a t e s and a c e t i c a c i d m a t e r i a l balances f o r Runs 79 t o 85 have been c a l c u l a t e d n e g l e c t i n g any leakage tihat occurred at the p i s t o n sampler. I n Run 79 the average t o t a l r a t e of leakage was 15 mis./min. w h i l e i n Runs 80 t o 85 the average leakage r a t e was 10 mis./min. when the p i s t o n was i n the l e f t - h a n d p o s i t i o n i n the p i s t o n b l o c k . No leakage took place i n Runs 80 t o 85 w h i l e the p i s t o n was p l a c e d i n the righ t - h a n d p o s i t i o n i n the p i s t o n b l o c k . As was mentioned e a r l i e r , sampling i n these runs was conducted by moving the p i s t o n from r i g h t to l e f t , the p i s t o n b e i n g r e t u r n e d to the r i g h t a f t e r a sample was taken. C r o s s - S e c t i o n a l C o n c e n t r a t i o n Measurements Table V shows the c o n c e n t r a t i o n data obtained by sampling the water phase w i t h the hypodermic syringe at p a r t i c u l a r c r o s s - s e c t i o n s at r i g h t angles to the a x i s of the column. No c o n c e n t r a t i o n g r a d i e n t was observed. However, the measurements are not i d e n t i c a l and standard d e v i a t i o n s of - 0.9x10"^ l b . m o l e s / f t ? and l e s s appear i n Table Y. These standard d e v i a t i o n s r e f e r to the c o n c e n t r a t i o n measurements of a s i n g l e run as l i s t e d i n the t a b l e . The c o n c e n t r a t i o n + —3 l e v e l corresponding to the f i g u r e of - 0.9 x 10 was 36.2 x 10"^ l b . m o l e s / f t ? and f o r the other runs approximately the same l e v e l a p p l i e d . 72 The volume of ketone e n t r a i n e d along w i t h the water phase of the syr i n g e sample v a r i e d from 0.5 to 1.0 mis. The t o t a l volume of these samples was approximately 30 cc. A m a t e r i a l balance c a l c u l a t i o n was made to determine approximately how much the c o n c e n t r a t i o n of the water phase of a t y p i c a l s y r i n g e sample would change, from c o n d i t i o n s e x i s t i n g i n the column, because of the presence of 1 ml of ketone phase. The -3 -3 change was found t o be from 37.0x10 ^ t o 36.6x10 o r a change of 0.4-xlO""^ l b . m o l e s / f t ^ From the p o i n t of view of t a k i n g a number of samples at one c r o s s - s e c t i o n , the c o n c e n t r a t i o n s should be f a i r l y comparable s i n c e almost a l l the s y r i n g e samples contained approximately the same volume of ketone. I t should be noted a l s o t h a t i n the column there were a l a r g e number of s m a l l ketone drops which d i d not appear to be moving ve r y f a s t r e l a t i v e to the column w a l l s . When these drops came near the s y r i n g e needle entrance they c o u l d be observed e n t e r i n g the needle. Because of the s i z e of these drops and because of t h e i r slow ascent i t i s p o s s i b l e t h a t they would be v e r y c l o s e t o being i n e q u i l i b r i u m w i t h the water phase of the e l e v a t i o n (above the n o z z l e t i p s ) b eing sampled. I f t h i s h ypothesis was v a l i d , and i f these drops formed the t o t a l volume of ketone entrainment i n the syringe samples, l i t t l e e x t r a c t i o n would r e s u l t because of the presence of t h i s entrainment and the measured water phase c o n c e n t r a t i o n i n the syr i n g e samples would have been very c l o s e t o the c o n c e n t r a t i o n of the water phase i n the column at tha t p o i n t . However, l a r g e r 73 ketone drops h i t t i n g the needle entrance would a l s o provide some entrainment presumably, so t h a t some u n c e r t a i n t y i n the r e s u l t s of the syringe samples remains. Table ..VT gi v e s the c o n c e n t r a t i o n of the water phase at P o s i t i o n 6 as a f u n c t i o n o f time a f t e r the s t a r t - u p of a run. The o b j e c t i n Sun 74 and 75 was to determine whether or not consecutive syringe samples, taken at one p o s i t i o n i n the c r o s s - s e c t i o n d u r i n g the steady s t a t e o p e r a t i o n of the column would show any v a r i a t i o n i n the measured c o n c e n t r a t i o n of + -3 a c e t i c a c i d . I n Run 74 a standard d e v i a t i o n of - 0.4x10 l b . m o l es/ft? was c a l c u l a t e d f o r s i x samples taken d u r i n g the steady s t a t e o p e r a t i o n of the column. A s i m i l a r value of i 0.1x10""^ l b . m o l e s / f t ^ was c a l c u l a t e d f o r Run 75. The average c o n c e n t r a t i o n s f o r these s i x samples f o r Runs 74 and 75 were 56.4x10"^ and 3 6.8xl0~^ l b . m o l e s / f t ^ r e s p e c t i v e l y . In Run 74 one ml. of ketone was e n t r a i n e d i n each s y r i n g e sample, whereas i n Run 75 o n l y 0 .5 mis. of ketone was e n t r a i n e d i n each syringe sample. The measured c o n c e n t r a t i o n of a c e t i c a c i d i n water phase and ketone phase samples + -3 3 i n c l u d e s a - 0.1x10 ' l b . m o l e s / f t . v a r i a t i o n due to the t i t r a t i o n technique of the author. T h i s being the case, consecutive s y r i n g e samples, taken at one p o s i t i o n i n the c r o s s - s e c t i o n d u r i n g the steady s t a t e o p e r a t i o n of the column, would be expected to show some v a r i a t i o n i n the measured c o n c e n t r a t i o n of a c e t i c a c i d . 74- P i s t o n Samples Compared To Probe Samples Tables V I I I and IX show the v a l u e s of the i n i t i a l ketone c o n c e n t r a t i o n s , C k i , as c a l c u l a t e d by Equations 7»8, o r 9» f o r Runs 79 t o 85. Included i n these t a b l e s are the values of the i n i t i a l ketone c o n c e n t r a t i o n s , Ckp, as measured w i t h the ketone phase probe and to which the values of C k i are to be compared. Table I I I g i v e s the sampling r a t e s and purging times which were used to o b t a i n a l l the probe samples. In some runs the values of C k i and Ckp are not comparable f o r a number of reasons. In some cases the probes were sampling at a p o s i t i o n one i n c h too h i g h above the p i s t o n a x i s and i n other cases the purge time t o o b t a i n uniform c o n c e n t r a t i o n s i n the probe samples d i d not meet the minimum purge time as s p e c i f i e d by Choudhury i n h i s work ( l n ) . Each run w i l l t h e r e f o r e be d i s c u s s e d i n t u r n to e x p l a i n how v a l u e s of C k i were c a l c u l a t e d d e s p i t e these e r r o r s i n experimental work. Run 79 This was the f i r s t run t h a t was made w i t h the p i s t o n sampler£: and average t o t a l leakages of 15 mis./min. were encountered. The p u r g i n g time f o r both probes was 10 minutes which was three to f o u r minutes l e s s than Choudhury's recommended minimum purge time. However, i t i s f e l t t h a t the c o n c e n t r a t i o n of the sample which was. obtained by the probe (15.0x10""^ l b . m o l e s / f t ^ ) i s f a i r l y r e p r e s e n t a t i v e s i n c e i t agrees w i t h Choudhury's value (16.0x10 l b . m o l e s / f t . ) obtained i n Run 61 (1) f o r approximately the same o p e r a t i n g c o n d i t i o n s and at the same height above the n o z z l e t i p s . Aside from t h i s , the v a l u e s of C k i as c a l c u l a t e d by Equation 7 d i f f e r by a very wide margin from the value of Ckp and no r e a l comparison between C k i and Ckp i s p o s s i b l e . I n Run 79 the ketone holdup i s very low (approximately 3.5%)• T h i s s i t u a t i o n corresponds to a highYw/y^ r a t i o . Upon examining Equation 7, i t i s easy to see t h a t r'fcwf - if Cwi)p + Cwifo? ; L J- 2 J must be known v e r y a c c u r a t e l y i n order to c a l c u l a t e v a l u e s of C k i w i t h some degree of accuracy. I f t h i s d i f f e r e n c e i s out by much, when m u l t i p l i e d by h i g h Vw/y^ r a t i o s , c a l c u l a t e d v a l u e s of C k i become g r o s s l y i n e r r o r , as can be seen i n Table V I I I . I n a d d i t i o n i t i s very easy t o measure Vw but much more d i f f i c u l t to measure Vk. At t h i s h i g h Vw/^ r a t i o e r r o r s i n Vk c o n t r i b u t e s i g n i f i c a n t l y to e r r o r s i n C k i (see Group C AVk i n Table X ) , as, a l s o , do e r r o r s i n Cwf and Cwi (see Groups D ACwf and E /SCwi). I t should a l s o be p o i n t e d out t h a t Cwi f o r Run 79 i n Table V I I I was obtained by t a k i n g s y r i n g e samples of the water phase immediately above and below the p i s t o n b l o c k , a n a l y z i n g them, and a p p l y i n g the r e s u l t s t o Equation 6. As can be seen i n Table V I I I t h i s value of Cwi does not agree e x a c t l y w i t h the value of Cwp, which was obtained by a n a l y s i s of a water phase sample taken at the a x i s of the p i s t o n by the 76 water phase pre/be. One reason f o r t h i s disagreement c o u l d be the presence of 0.5 mis. of ketone phase e n t r a i n e d i n each syr i n g e sample. This could produce a f i n a l c a l c u l a t e d value of Cwi low by as much as - 0.2 x 10 J l b . m o l e s / f t . A second reason c o u l d be t h a t i n s u f f i c i e n t time was allowed f o r purging the probes i n order to o b t a i n a sample of the proper uniform c o n c e n t r a t i o n . A t h i r d reason, mentioned e a r l i e r , c o u l d be t h a t syringe samples, taken at one p o i n t i n the c r o s s - s e c t i o n d u r i n g the steady s t a t e o p e r a t i o n of the column, may not always be t r u l y r e p r e s e n t a t i v e of the water phase at t h a t p a r t i c u l a r c r o s s - s e c t i o n . T h i s , p l u s the u n c e r t a i n t y of the t i t r a t i o n technique c o u l d cause Cwi and Cwp to be d i f f e r e n t . A d m i t t e d l y the d i f f e r e n c e between these two i n Table V I I I i s s m a l l , but p a r t i c u l a r l y f o r the c o n d i t i o n s of Run 79•> e r r o r s i n Cwi are important i n producing e r r o r i n C k i (Table X ) . Upon examining the r e s u l t s obtained i n Run 79 i t was decided to r e a d j u s t the f l o w r a t e v a l v e s to i n c r e a s e the ketone phase holdup and to c r e a t e a more favourable Vw/y^ r a t i o . Runs 80 and 81 r e s u l t e d . Runs 80 and 81 In Runs 80 and 81 i t was found t h a t the probes had been l o c a t e d one i n c h too h i g h above the p i s t o n a x i s when sampling was t a k i n g p l a c e w i t h them. As a r e s u l t , no matter what the p u r g i n g times f o r the probes were, no proper comparison of C k i w i t h the r e s u l t i n g v a l ue of Ckp can be made. 77 However, t o draw some form of comparison reference i s made to Run 66 by Choudhury (1) which i s a run of approximately the same op e r a t i n g c o n d i t i o n s , and i n which, proper p u r g i n g times were used f o r h i s sampling w i t h the probes. Choudhury's v a l u e s f o r Cwp and Ckp, at a height above the n o z z l e t i p s at which the a x i s of our p i s t o n was l o c a t e d ( 1 . 5 9 - f t . ) , were 2 5 . 3 x 10""^ -3 / 3 and 10.0x10 ^ l b . moles/ft-; r e s p e c t i v e l y . A value of Cwi was obtained f o r each run by use of the syr i n g e samples from Run 80 and a p p l y i n g them to Equation 6. The r e s u l t agrees w i t h Cwp from Choudhury's work i n Run 66 at the same l o c a t i o n . Only one p i s t o n sample was taken i n Run 80 because i n a d v e r t e n t l y the p i s t o n compartment, which was to s l i d e i n t o l i n e w i t h the column when a sample was taken, was not f i l l e d w i t h water phase s o l u t i o n . When the p i s t o n sample was taken the o p e r a t i o n of the column was d i s r u p t e d completely and no f u r t h e r sampling was p o s s i b l e . However, the one value of C k i which was c a l c u l a t e d , 9.1 x 10"^ l b . mole was of the c o r r e c t order of -3 magnitude but s l i g h t l y lower than the value of 10.0 x 10 ' l b . m oles/ft? which was obtained from Choudhury's work ( 1 ) . Run 81 was a repeat of Run 80, except t h a t the sy r i n g e samples had to be omitted because too much ketone phase ( 2 t o 3 mis. i n Run 81) was being e n t r a i n e d along w i t h the water phase. However, val u e s of C k i were c a l c u l a t e d f o r the two p i s t o n samples by u s i n g Cwi from Run 80 as a l r e a d y 78 mentioned. The f i r s t v alue of C k i (10.1x10""^) agreed very- w e l l w i t h Choudhury's value (10.OxlO -^) hut the second value —3 of C k i (16.2 x 10 ) was much higher than Choudhury's v a l u e . The reason t h a t the second p i s t o n value of C k i was c a l c u l a t e d t o be so h i g h was t h a t Cwf (25.6x10""^) was found to be h i g h e r than Cwi (25.3x10""^). A t h i r d p i s t o n sample was taken to p r o v i d e a check on the ketone phase holdup values of the other p i s t o n samples and analyses were not c a r r i e d out. In Runs 80 and 81 a more f a v o u r a b l e Vw/y^. r a t i o was o b t a i n e d , and, as can be seen i n Table X, i n the C A V k Group, the e r r o r s i n Vk do not c o n t r i b u t e s i g n i f i c a n t l y t o the error-, i n C k i . However, the main d i f f i c u l t y i n Runs 80 and 81 was t h a t too l i t t l e e x t r a c t i o n was t a k i n g p l a c e i n the column i n the r e g i o n of the p i s t o n sampler. In other words the phases were near e q u i l i b r i u m t h e r e . Thus when a p i s t o n sample was taken Cwf d i f f e r e d v ery l i t t l e from Cwi. This s m a l l d i f f e r e n c e was very hard to p i c k up by the t i t r a t i o n technique and i t was decided to r e a d j u s t the f l o w r a t e s so t h a t the g r e a t e r p a r t of the o v e r - a l l e x t r a c t i o n of the column took place i n the r e g i o n of the p i s t o n sampler. Runs 82 and 83 r e s u l t e d . Runs 82 and 83 In Run 82, as i n Runs 80 and 81, the .probes were l o c a t e d one i n c h too h i g h above the a x i s of the p i s t o n when sampling w i t h them. As a r e s u l t Run 83 was made as a repeat of Run 82. The probes were r e l o c a t e d to sample both phases at the a x i s of the p i s t o n . 79 In Run 83 more than the minimum purge time t o o b t a i n a uniform sample w i t h the probes was used as can be seen i n Table I I I . F or reasons mentioned e a r l i e r the s y r i n g e samples were d i s c o n t i n u e d and Cwi was taken as Cwp s i n c e no other a l t e r n a t i v e presented i t s e l f . Values of C k i were c a l c u l a t e d , both i n Runs 82 and 83, w i t h Cwi taken as Cwp from Run 83. In these two runs c a l c u l a t e d v a l u e s of C k i v a r i e d from 10.5x10 to 14.1x10"^ l b . m o l e s / f t ? , a l l of which were lower than the value of Ckp ( 1 5.6x10"^), again from Run 83. Values of Cwf and of Ckf d i d not v a r y by more than 0.2x10"^ l b . m o l e s / f t ^ i n both runs and the d i f f e r e n c e s i n the c a l c u l a t e d values of C k i must be a t t r i b u t e d mostly t o the d i f f e r e n c e s i n the Vw/yjj. r a t i o which v a r i e d from 10.6 to 11.1, as can be c a l c u l a t e d from Table V I I I . The f l o w r a t e s i n Runs 82 and 83 were such t h a t the d e s i r e d , g r e a t e r percentage of the t o t a l e x t r a c t i o n of the column took p l a c e i n the r e g i o n of the p i s t o n sampler. Thus a f t e r a p i s t o n sample had been taken a g r e a t e r amount of e x t r a c t i o n continued to take place from the water phase to the ketone phase of the p i s t o n sample t i l l e q u i l i b r i u m was reached. As can be seen from Table V I I I d i f f e r e n c e s between Cwf and Cwi of 0.6x10"^ to 0.8xl0~^ l b . m o l e s / f t ? were c a l c u l a t e d f o r a l l the p i s t o n samples of both runs. Upon examining the r e s u l t s of Runs 82 and 83 i t was decided to i n c r e a s e the ketone phase holdup s t i l l f u r t h e r and s t i l l m a i n t a i n a great percentage of the t o t a l e x t r a c t i o n i n the r e g i o n of the p i s t o n sampler. Runs 84 and 85 r e s u l t e d . 80 Runs 84 and 85 For the f i r s t probe sample of Run 84 the pu r g i n g time used p r i o r to sampling the water and ketone phases at the a x i s of the p i s t o n was lower than the minimum purge time s p e c i f i e d by Choudhury. For the second probe samples of Run 84 and f o r Run 85, a repeat of the o p e r a t i n g c o n d i t i o n s of Run 84, s u f f i c i e n t purge time was allowed. However, d e s p i t e the f a c t t h a t s u f f i c i e n t purge time was not allowed i n the f i r s t probe samples of Run 84, the va l u e of Cwp agrees w i t h t h a t of the second probe sample f o r Run 84 and w i t h t h a t of Run 85. Ckp i n Run 85 i s a l i t t l e h i g h e r than Ckp of Run 84, but the second value f o r Run 84 agrees w i t h the f i r s t value f o r t h a t run. I n Run 84 the probes were lowered to the a x i s of the p i s t o n both before and a f t e r the 8 p i s t o n samples were taken. Thus there are two sets of probe samples f o r t h i s run. I t would seem t h a t , i n f a c t , p urging times were r e a l l y adequate f o r a l l samples i n both runs. Values of C k i i n Run 84 were c a l c u l a t e d u s i n g the water phase probe v a l u e , Cwp, as the i n i t i a l c o n c e n t r a t i o n of the water phase at the time of sampling, Cwi. The v a l u e s of the c a l c u l a t e d i n i t i a l ketone c o n c e n t r a t i o n , C k i , f o r the 8 -3 -3 / 3 p i s t o n samples v a r i e d from 11.0x10 ' to 15.0x10 ^ l b . m o l e s / f t . T h e i r average was 12.1x10"^ l b . m o l e s / f t ^ and t h e i r standard + -3 3 d e v i a t i o n was - 0.7x10 ^ l b . m o l e s / f t . The average volume of the ketone phase, Vk, f o r the 8 p i s t o n samples was 13.6 mis. 81 The standard d e v i a t i o n of t h i s volume was - 0.5 mis. Corresponding v a l u e s f o r the water phase volumes, Vw, were 101.3 mis. and - 0.2 mis. r e s p e c t i v e l y . A l l the v a l u e s of the c a l c u l a t e d i n i t i a l ketone c o n c e n t r a t i o n were l e s s than the value of Ckp (16.4-xlO" 5). I n Run 85 the v a l u e s of C k i as c a l c u l a t e d by Equation 9, were v e r y c l o s e to the v a l u e s of C k i i n Run 84- which were c a l c u l a t e d by Equation 8. The average v a l u e of C k i f o r Run 85 was 12.0x10 y l b . m o l e s / f t . w i t h a standard d e v i a t i o n of - 0.5x10""^ l b . m o l e s / f t ^ f o r the f o u r p i s t o n samples. In a l l the runs the value of C k i , as c a l c u l a t e d by Equation 7 or 8, f o r the p i s t o n samples was s m a l l e r than the value as measured by the ketone phase probe except i n one case. In most cases even the value of C k i p l u s the corresponding expected maximum e r r o r of C k i was s m a l l e r than the corresponding value of Ckp. As s t a t e d e a r l i e r i t was thought t h a t v a l u e s of Ckp p o s s i b l y c o u l d be too l a r g e because of the residence time of the ketone drops at the ketone probe entrance, and because of the " i n t e r f a c e of coalescence" sometimes created t h e r e . Both of these c o n d i t i o n s would a l l o w t r a n s f e r of a c e t i c a c i d i n t o the ketone phase, and of course, such t r a n s f e r would not have occurred i f the probes had not been p r e s e n t . 82 In a d d i t i o n t o the r e l i a b i l i t y of Ckp samples, a p o i n t needing c o n s i d e r a t i o n i s whether or not Cwp ( o r , Cwi) i s a r e p r e s e n t a t i v e sample of the water phase c o n c e n t r a t i o n to be compared w i t h Cwf of the p i s t o n sample. Cwp i s assumed t o be an average b u l k c o n c e n t r a t i o n of the water phase at the sampling p o i n t . I t i s p o s s i b l e t h a t the water phase probe does not a f f o r d adequate sampling of the r e g i o n near the drops. T h i s would suggest t h a t the values of Cwp would be too h i g h and t hose of C k i as c a l c u l a t e d by Equation 8, too low. I n other words the water phase probe may not give t r u e b u l k c o n c e n t r a t i o n s of the m a t e r i a l accompanying the drops i n t a k i n g a p i s t o n sample and f u r t h e r i n v e s t i g a t i o n i s r e q u i r e d to see whether or not Cwp can be used f o r the i n i t i a l water phase c o n c e n t r a t i o n i n the m a t e r i a l balance equation. In the case of the ketone probe samples a s i m i l a r e r r o r might be much more s e r i o u s because drops are c o l l e c t e d out of p r o p o r t i o n to the a c t u a l h o l d up i n the column. Approximation of E r r o r s The approximate maximum e r r o r due to each v a r i a b l e taken i n t o account i n Equation 13 was summarized i n Table X. As can be seen the expected e r r o r due to each v a r i a b l e can be reduced by o p e r a t i n g at l a r g e ketone holdups and by a d j u s t i n g f l o w r a t e s to encourage a l a r g e amount of the e x t r a c t i o n to take p l a c e i n the r e g i o n of sampling. (See columns i n Table X g i v i n g Vk, Vw, Cwf and Cwi). I t can be seen t h a t the e r r o r i n a c a l c u l a t e d q u a n t i t y t h a t i s a f u n c t i o n of s e v e r a l d i r e c t l y measured q u a n t i t i e s depends on (a) the nature of the f u n c t i o n , (b) the magnitudes 83 of the measured q u a n t i t i e s , and (c) the magnitudes of the e r r o r s (10). I t i s p o s s i b l e t h a t Equation 1-3, as used w i t h a l l signs p o s i t i v e , q u i t e probably overestimates the e r r o r i n v o l v e d i n the c a l c u l a t e d q u a n t i t y . I t takes no account of the p r o b a b i l i t y of compensating e r r o r s . T h i s f a c t can be shown e a s i l y by s i m u l a t i n g the t a k i n g of a p i s t o n sample. A ketone phase, c a l l e d C k i , was analyzed and found to have a c o n c e n t r a t i o n of 7.06x10"^ l b . m o l e s / f t l A water phase, c a l l e d Cwi, was analyzed and found to have a concentration" of - 3 / 3 32.67x10 ^ l b . m o l e s / f t . Volumes of these phases were mixed i n the c o l l e c t i o n f l a s k i n a r a t i o t y p i c a l of a p i s t o n sample. The phases were w e l l mixed, allowed to s e t t l e , and t h e i r volumes measured. The phases were then separated and analyzed, t h e i r c o n c e n t r a t i o n s being designated as Ckf and Cwf. E q u a t i o n 5 was then used to c a l c u l a t e C k i which was compared t o C k i as -3 measured i n i t i a l l y as 7*06x10 . Table XiLf shows the r e s u l t s of f o u r such experiments. The average value of C k i , as -3 / 3 c a l c u l a t e d by Equation 5, was 7.30x10 ^ l b . moles/ft-; + -3 I n d i v i d u a l v a l u e s d i f f e r e d from t h i s average by - 0.3x10 y l b . m o l e s/ft? T h i s example i l l u s t r a t e s how e r r o r s c o u l d tend to be compensating as the average value of the c a l c u l a t e d C k i d i f f e r s from the measured value by o n l y 0.24x10"^ l b . moles/ f t 2 However, Equation 13 would l e a d one to b e l i e v e t h a t 84 Table XII Simulated Piston Samples No. Volumes Concentrations of Acetic A c i d Tr~+r,r^1Sma+^ l b - moles/ft? x 10 5 iietjone waxier Vk Vw Cwf Ckf Cwi Cki Cki T i t r a t e d T i t r a t e ! T i t r a t e d Calc'd T i t r a t e d 1 10.0 104.9 31.89 1 5 . 1 5 32.67 6.97 7.06 2 10.5 104.7 31.89 1 5 . 1 5 32.67 7.37 7.06 3 10.3 i 105.2 31.89 1 5 . 1 5 32.67 7.19 7.06 4 10.8 104.5 31.89 15.15 32.67 7.60 7.06 Average 7 . 3 0 85 maximum e r r o r s of approximately - 2.0x10"^ l b . m o l e s / f t ? would ' be p o s s i b l e f o r each, c a l c u l a t e d value of C k i . Salinometer Measurements Table X I shows the r e s u l t s of the measurements of the r e s i s t a n c e s of the water phase p o r t i o n of the f i r s t f i v e p i s t o n samples taken i n Run 84. I t a l s o shows the c o n c e n t r a t i o n s of the samples corresponding to these r e s i s t a n c e measurements as obtained from F i g u r e 32, the c a l i b r a t i o n curve, and compares these w i t h c o n c e n t r a t i o n s determined by t i t r a t i o n . As can be seen the two values were found to be q u i t e d i f f e r e n t . I t was found on the t r i p to Nanaimo t h a t the p i s t o n samples were hazy, whereas the c a l i b r a t i o n samples were not. (Both had been kept i n the r e f r i g e r a t o r f o r f i v e days). The haze was probably a f i n e suspension of ketone which, as mentioned e a r l i e r , would a f f e c t the r e s i s t a n c e readings c o n s i d e r a b l y . On r e t u r n i n g from Nanaimo the c o n c e n t r a t i o n s of the f i v e p i s t o n samples were analyzed again by t i t r a t i o n and the r e s u l t s were found to check w i t h the c o n c e n t r a t i o n s measured p r i o r t o the t r i p . The same cou l d be s a i d f o r the c a l i b r a t i o n samples which were a l s o checked. As the salinometer r e s u l t s d i d not agree w i t h the t i t r a t i o n r e s u l t s the method was not used f u r t h e r i n the present r e s e a r c h . Table X I suggests t h a t the d i f f e r e n c e between the salinometer r e s u l t s and the t i t r a t i o n r e s u l t s depends on the source of the s o l u t i o n . However more work would be needed to c o n f i r m t h i s p o i n t . 86 CONCLUSIONS Con c e n t r a t i o n t r a v e r s e s of the continuous water phase s o l u t i o n were made across the c r o s s - s e c t i o n of the column at d e f i n i t e e l e v a t i o n s above the no z z l e t i p s and no c o n c e n t r a t i o n g r a d i e n t s were found. However, standard d e v i a t i o n s as h i g h as - 0 .9x10 ^ l b . m o l e s / f t . about an average c o n c e n t r a t i o n of 36 .2x10"^ l b . mo l e s / f t ? were r e p o r t e d . The hypodermic s y r i n g e method of measuring the c o n c e n t r a t i o n of the water phase s o l u t i o n i n the tower was not always operable because the presence of a small volume of ketone phase c o u l d change the c o n c e n t r a t i o n of the water phase as e x t r a c t i o n would continue a f t e r a syringe sample was taken u n t i l e q u i l i b r i u m was reached between the two phases. The volume of ketone i n the water phase samples was a p p r e c i a b l e when the column was operated at higher ketone holdups so t h a t the syringe method co u l d not beused i n c o n j u n c t i o n w i t h many of the runs i n which p i s t o n samples were taken. However, when the c r o s s - s e c t i o n a l t r a v e r s e s were made, the holdup was low and approximately the same small volume of ketone was e n t r a i n e d i n each s y r i n g e sample. Therefore the r e s u l t s are not much i n e r r o r and c e r t a i n l y comparable. 87 C a l c u l a t e d i n i t i a l ketone c o n c e n t r a t i o n s are s t i l l u n c e r t a i n u n t i l i t can be determined whether or not the measured water phase probe c o n c e n t r a t i o n s , Cwp, are r e p r e s e n t a t i v e samples of the aqueous phase. In the p i s t o n method of sampling, the r e s u l t s are extremely s e n s i t i v e t o the r e s u l t s of the a n a l y s i s of the water phase samples. The value of the c a l c u l a t e d i n i t i a l ketone c o n c e n t r a t i o n f o r the p i s t o n samples, C k i , p l u s the approximate maximum e r r o r of t h i s c a l c u l a t e d v a l u e , A C k i , was almost always l e s s than the measured probe c o n c e n t r a t i o n , Ckp. Thus val u e s of Ckp, are probably too l a r g e because of the r e s i d e n c e time of the ketone drops at the ketone probe entrance and because of the i n t e r f a c e sometimes cr e a t e d t h e r e . T h i s c o n c l u s i o n , however, i s c e r t a i n l y dependent on the water phase probe sample being r e p r e s e n t a t i v e . The p i s t o n sampler proved to be a quick and easy means of l i t e r a l l y removing a s e c t i o n of the o p e r a t i n g column from the e x t r a c t i o n tower without s e r i o u s l y i n t e r r u p t i n g the o p e r a t i o n of the apparatus. I t i s recommended t h a t i n a d d i t i o n to c a r r y i n g out f u r t h e r s t u d i e s on sampling w i t h the p i s t o n , f u r t h e r work be done on the effiect of sampling r a t e on the value of the ketone c o n c e n t r a t i o n obtained by sampling w i t h the probe. The work of Choudhury ( l c ) was done at a l o c a t i o n i n the column at which the phases were c l o s e to e q u i l i b r i u m so t h a t o n l y a s m a l l e f f e c t on the ketone c o n c e n t r a t i o n would r e s u l t from l i n g e r i n g and c o a l e s c i n g of ketone drops at the probe entrance. 88 NOMENCLATURE Symbols Cwi C o n c e n t r a t i o n of a c e t i c a c i d i n the water phase e n t e r i n g the top of the column, l b . m o l e s / f t 3 Cw2 Co n c e n t r a t i o n of a c e t i c a c i d i n water phase l e a v i n g the bottom of the column, l b . moles/ftv C k i C o n c e n t r a t i o n of a c e t i c a c i d i n the ketone phase l e a v i n g the top of the column, l b . m o l e s / f t ? Ck2 Co n c e n t r a t i o n of a c e t i c a c i d i n the ketone phas§ e n t e r i n g the bottom of the column, l b . mo l e s / f t ? Cwi I n i t i a l steady s t a t e c o n c e n t r a t i o n of a c e t i c a c i d i n the water phase i n the column at the sampling p o i n t , l b . m o l e s / f t 5 Cwf F i n a l c o n c e n t r a t i o n of a c e t i c a c i d i n the water phase p o r t i o n of the c o l l e c t e d p i s t o n sample a f t e r e q u i l  i b r i u m has been reached w i t h the ketone phase p o r t i o n , l b . m o l e s / f t ? Cwp Con c e n t r a t i o n of a c e t i c a c i d i n the water phase at the time of sampling w i t h the water phase probe, l b . m o l e s / f t 5 C k i ; • C a l c u l a t e d i n i t i a l s t e a d y - s t a t e c o n c e n t r a t i o n of a c e t i c a c i d i n ketone phase i n the column at the a x i s of the p i s t o n , l b . m o l e s / f t 3 Ckf P i n a l c o n c e n t r a t i o n of a c e t i c a c i d i n the ketone phase p o r t i o n of the c o l l e c t e d p i s t o n sample a f t e r e q u i l i b r i u m has been reached w i t h the water phase p o r t i o n , l b . m o l e s / f t 2 Ckp C o n c e n t r a t i o n of a c e t i c a c i d i n the ketone phase at the time of sampling w i t h the ketone phase probe, l b . m o l e s / f t 3 C w i ) m I n i t i a l c o n c e n t r a t i o n of a c e t i c a c i d i n the water : phase i n the column at the top of the p i s t o n b l o c k * by sampling w i t h a hypodermic s y r i n g e , l b . m o l e s / f t ? 89 Cwi) B Cwf Cwf A Cwi ACwf AC k f Lk Lw A Nw Nk Q t q s Vw Vk n Vw As Cwi)g, , except at the "bottom of the p i s t o n b l o c k . F i n a l c o n c e n t r a t i o n of a c e t i c a c i d i n the water phase remaining w i t h the ketone phase a f t e r immediately drawing the major p o r t i o n of the water phase from the ketone phase of the p i s t o n samples i n Run 85. . This value i s i n e q u i l i b r i u m w i t h the ketone phase, l b . m o l e s/ft? F i n a l c o n c e n t r a t i o n of a c e t i c a c i d i n the major p o r t i o n of the water phase which was drawn from the ketone phase of the p i s t o n samples i n Run 85» l b . m o l e s/ft? Assumed e r r o r i n Cwi, l b . m o l e s / f t ? •z Assumed e r r o r i n Cwf, l b . m o l e s / f t . Assumed e r r o r i n Ckf, l b . m o l e s / f t ^ Ketone phase f l o w r a t e , f t ? / h r . f t . Water phase f l o w r a t e , f t ? / h r . f t ? 2 C r o s s - s e c t i o n a l area of the column, f t . T r a n s f e r r a t e of a c e t i c a c i d based on the i n l e t and o u t l e t water phase c o n c e n t r a t i o n s , l b . moles/hr. T r a n s f e r r a t e of a c e t i c a c i d based on the i n l e t and o u t l e t c o n c e n t r a t i o n s of the ketone phase, l b . moles/hr. The c a l c u l a t e d value of some unknown f u n c t i o n which c o n t a i n s a number of measured q u a n t i t i e s . The measured q u a n t i t i e s i n some unknown f u n c t i o n . Volume of water phase p o r t i o n of the c o l l e c t e d p i s t o n samples, mis. Volume of ketone phase p o r t i o n of the c o l l e c t e d p i s t o n samples, mis. Small volume of water phase remaining w i t h the ketone phase p o r t i o n a f t e r immediately drawing o f f the major p o r t i o n of the water phase i n the p i s t o n samples of Run 85, mis. 90 Vw Volume of the major p o r t i o n of water phase which was immediately drawn from the p i s t o n samples i n Eun 85, mis. AVw Assumed e r r o r i n Vw, mis. H Percentage holdup, i . e . the percent of the t o t a l volume of the p i s t o n sample occupied by ketone. Groups i n Equation 14 A' 9 C k i 3Ckf = 1, dimensionless B 3Cki 3Vw • ^ (Cwf-Cwi), l b . m o l e s / f t ? m l . C 3Cki 3Vk Vw ~ ~ Vk 2 (Cwf-Cwi), l b . moles/ft?ml. D 3Cki acwf Vw = Vk ' dimensionless E 3Cki 3 Cwi Vw " Vk ' dimensionless 91 LITERATURE CITED 1. Choudhury, P r o s e n j i t R a i , M.A. Se. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, 1959. l a . I b i d . , p-17. l b . T^)id. , p -54. l c . I b i d . , P-50, 58. I d . I b i d . » P -7 . l e . I b i d . i P - l l . I f . I b i d . , P-IO. I g . I b i d . , p-16. I h . I b i d . » P-12, 15, 24, 26. I i . I b i d . . . P-17. i d . I b i d . , » P-21. I k . I b i d . , p - 2 2 . 11. I b i d . , P-23. lm. I b i d . , P-25. l n . I b i d . , P-59. 2. Cavers, S.D., and Ewanchyna, J.E., Can. J . of Chem. Eng. 25, 113, (1957). 3. G i e r , T.E. and Hougen, J.O., Ind. Eng. Chem. 4£, 1562, (1955). 4. Geankoplis, C.J., and Hixon, A.N., Ind. Eng. Chem. 42, 1141, (1950). 5. 'Geankoplis, C.J., W e l l s , P.L., and Hawk, E.L., Ind. Eng. Chem. 4J>, 1848, (1951). 6. Kreager, R.M., and Geankoplis, C.J., Ind. Eng. Chem. 2156, (1955). 92 7. Vogt, H.J., and Geankoplis, C.J., Ind. Eng. Chem. 46, 1763, (195^). 8. Lepage, N.A.W., B.A.Sc. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, 1956. 9. Dean, R.R., B.E. T h e s i s , U n i v e r s i t y of Saskatchewan, 1954. 10. M i c k l e y , H.S., Sherwood, T.K., Reed, C.E., A p p l i e d Mathematics i n Chemical E n g i n e e r i n g , McGraw-Hill Book Co., New York, 2 n d E d i t i o n , 1957. 11. Paquette, R.G., A M o d i f i c a t i o n of the Wenner-Smith-Soule S a l i n i t y Bridge For the Determination of S a l i n i t y In Sea Water, T e c h n i c a l Report No. 61, Department of Oceanography, U n i v e r s i t y of Washington, S e a t t l e 5, Washington, 1958. 12. Paquette, R.G., p e r s o n a l communication accompanying Reference 11, June 2 , 1959. 93 A P P E N D I C E S 94 APPENDIX I SAMPLE CALCULATIONS The following sample c a l c u l a t i o n s were made using the data from Run 84, P i s t o n Sample i . The data u s u a l l y were recorded i n the data hooks to four s i g n i f i c a n t f i g u r e s whereas i n the tables of t h i s t h e s i s the corresponding data have been rounded o f f to three s i g n i f i c a n t f i g u r e s . 1) Rate of Transfer of A c e t i c Acid (a) Nw = LwA (Cwi - Cw2) 1 where Lw = 90.9 f t ? / h r . / f t ? A = 0.0122? f t ? Cwi = 5 0.23xl0~ 3 l b . moles/ft? Cw2 = 3 2 .52xlO~ 5 l b . moles/ft? Nw = (90 .9)(0.01227)(50.23xlO~ 5-32 .52xlO~ 3 ) = 19.75x10" 5 l b . moles/hr. reported as = 19.8x10"^ l b . moles/hr. (b) Nk = LkA(Ckl - Ck2) 2 where Lk = 90.5 f t ? / h r . / f t ? A = 0.01227 f t ? Cki = 24.83xl0" 5 l b . moles/ft? Ck2 = 7.06xlO" 5 l b . moles/ft? Nk = (90 .5)(0.01227)(24.83xl0" 5 -7.06xl0"" 5) = 19.72xl0~ 5 l b . moles/hr. reported as = 19.7x10"^ l b . moles/hr. 95 ( C ) N - N w + 3 from (a) and (b) H - 1 9 ' 7 ^ 1 Q " 3 + l ^ ? ^ " 3 = 19. 7 4 x l 0 " 3 l b . moles/hr. r e p o r t e d as = 19.7x10"^ l b . moles/hr. (d) Percentage D e v i a t i o n = (22jj££)l00 4- from ( a ) , ( b ) , and (c) Percentage D e v i a t i o n . ( 1 9-7 ^ e ^ > ^ Z g x l 0 " 3 ) 3 c 1 0 0 = 0.158 % rep o r t e d as =0.2% A c e t i c A c i d M a t e r i a l Balance Percentage D i f f e r e n c e Percentage D i f f e r e n c e = A c i d I n - A c i d Out x 100 ±JL A c i d I n = (LwACwl+LkACk2) - (LwACw2+LkACkl) x 100 LwACwl + LkACk2 A c i d In = ( 9 0 . 9)(0 . 0 1 2 2 7 ) ( 5 0.23xl0~ 3 ) + ( 9 0 . 5)(0.0122?) , (7.06x10"^) • 6 5 .84x10" 5 l b . moles/hr. A c i d Out = (90.9)(0 . 0 1 2 2 7)(32 . 5 2 x l O" 3)+(90 . 5)(0.0 1 2 2 7 ) , (24.83xl.0~ 5 = 6 5 . 8 2 x l 0 " ^ l b . moles/hr. Percentage D i f f e r e n c e = /63»84 - 6 5 . 8 2 ^ ^ ( g j T s Z f — n o o = +0.05% 96 3. C a l c u l a t e d I n i t i a l P i s t o n Ketone C o n c e n t r a t i o n s , C k i C k i = H (Cwf - Cwp) + Ckf 8 assuming Cwp = Cwi Here, Vk = 13.6 mis. Vw = 101.4 mis. Cwf = 4 0 . 3 2 x l 0 ~ 5 l b . m o l e s / f t ? Cwp = 4 1 . 2 3 x l 0 " 5 l b . m o l e s / f t ? Ckf = 19.7x10""5 l b . m o l e s / f t ? C k i = 101.4 ( 4 0 . 3 2 x l 0 - 3 - 4 1 . 2 3 x l 0 " 5 ) + 1 9 . ? x l 0 " 5 13.6 = 12 . 9 x 10" 5 l b . m o l e s / f t ? 4. Maximum Approximate E r r o r A C k i = A'ACkf + B AVw + C AVk + D A Cwf + E A Cwi 13 where A' = 3Cki = 1 3Ckf B = 3Cki = 1 (Cwf - Cwi) d Vw Vk C = 3Cki = -Vw. (Cwf - Cwi) d Vk V k 2 D = gCki = Vw 9Cwf Vk E = flCki = Vw 0Cwi Vk and where C k i » Vw (Cwf - Cwi) + Ckf Vk Values of AVw, AVk, AVkf, A Cwf, A Cwi have been estimated as equal to 97 AVw = ±0.2 mis. AVk = ±0.2 mis. ACkf = ±0.1xl0" 5 l b . m o l e s / f t ? ACwf = ±0.1xl0~ 5 l b . m o l e s / f t ? ACwi = ±0.1xl0~ 5 l b . m o l e s / f t ? values have been g i v e n s i g n s such t h a t A C k i i s a maximum i n the f o l l o w i n g .*. ACki = ( l ) ( 0 . 1 x l 0 ~ 3 ) + 1| > 6(40.32xlO~ 5-4-1.23xlO~ 3) (0 + 1 0 ^ ^ 2 ( 4 0 . 3 2 x l 0 ~ 5 - 4 1 . 2 3 x l 0 - 5 ) (0.2)+,101.4 N(0.1xlO~ 3 ^ 1 3 . 6 ; + ^ a m ^ a o . i x i o " 5 ) ^ 13.6 ; = (0.1 + 0.01 + 0.1 + 0 . 75 + 0 . 7 5)10" 3 = 1 . 7 1 x l O " 3 l b . m o l e s / f t ? 5« Ketone Holdup Percentage H =-( Vk xlOO 10 Ww+Vk; = / 13.6 \ 100 ^101.4+13.6 ; = 11.8% The next sample c a l c u l a t i o n was made u s i n g the data from Sun 85, P i s t o n Sample i . 98 6. C a l c u l a t i o n of C k i When Phases of P i s t o n Sample Were Separated Immediately A f t e r the P i s t o n Sample Was Taken C k i » C wf/VWN + Cwf/Vwx - Cwp ,Vw\ + Ckf 9 W k ; W k ; ^Vk ; where f o r Run 85, p i s t o n sample i Cwf = 40.09xl0"" 5 l b . m o l e s / f t ? •t _ x 5 Cwf = 38.6x10 ^ l b . m o l e s / f t . from e q u i l i b r i u m curve and i n e q u i l i b r i u m w i t h Ckf = 1 9 . 5 9 x l O " 5 l b . mo l e s / f t ? Cwp = 41.17xl0"* 5 l b . mo l e s / f t ? Vw = 100.0 mis. Vw = 1.0 mis. Vk = 13.2 mis. Vw = Vw + Vw = 100.0 + 1.0 = 101.0 mis. . *. C k i = ,100^0^(40.09x10*"^) +/ 1. Ox (38.6x10"^) ( ' " T 3 T 2 ; k 1 3 . 2 ; *"5 , .0x --' n" 5 ^1 7 ; -+ ( 4 1 . 1 7 x l 0 " 3 ) / l p l y O N + 19.59xlO"~ 5 ^ 13.2J = 11.21 x IO"*5 l b . mo l e s / f t ? 99 APPENDIX I I VOLUME CHANGES DUE TO CHANGES IN MUTUAL SOLUBILITY Data f o r the mutual s o l u b i l i t y f o r the system methyl i s o b u t y l k e t o n e - a c e t i c acid-water was taken from Sherwood, T.K., Evans, J.E., and Longcor, Ind. Eng. Chem., 3 1 , 1144, ( 1 9 3 9 ) . Using these data the s o l u b i l i t y curve was drawn on t r i a n g u l a r graph paper, as shown i n F i g u r e 35 • I t was d e s i r e d to know whether or not any volume changes occur, other than those due t o the t r a n s f e r of a c e t i c a c i d because of the change i n mutual s o l u b i l i t y accompanying t h i s t r a n s f e r . As an example a s i n g l e - c o n t a c t mixer has been chosen. In t h i s example a c e t i c a c i d c o n c e n t r a t i o n s have been used f o r the i n l e t streams s i m i l a r to those which a p p l i e d i n the experimental work. F i g u r e 3 6 , shows a t y p i c a l s i n g l e - c o n t a c t e x t r a c t i o n mixer. The assumed composition of 100 l b s . of i n l e t water phase s o l u t i o n , s a t u r a t e d w i t h MIBK, i s 4 . 3 l b s . of a c e t i c a c i d , 1 .7 l b s . of MIBK, and 9 4 . 0 l b s . of water, which corresponds t o the composition of 100 l b s . of i n l e t water phase used i n the experimental work. The assumed composition of 100 l b s . of i n l e t ketone phase, which i s s a t u r a t e d w i t h water, i s 0.8 l b s . of a c e t i c a c i d , 2 . 5 l b s . of water, and 9 6 . 7 l b s . of MIBK, which A C E T I C ACID M I B K WATER FIGURE 3 5 - MUTUAL SOLUBILITY CURVE (WEIGHT % ) F O R THE S Y S T E M M E T H Y L I S O B U T Y L K E T O N E — ACETIC A C I D - WATER AT 2 5 ° C 101 corresponds to the composition of 100 l b s . of i n l e t ketone phase used i n the experimental work. O u t l e t water phase B l b s . I n l e t ketone phase or s o l v e n t , S l b s . Figure 36. S i n g l e - C o n t a c t E x t r a c t i o n Mixer The i n l e t water phase composition and the i n l e t ketone phase composition have been l o c a t e d as p o i n t s F and S on Figure 35• The mixer i s assumed t o be an i d e a l stage so t h a t e q u i l i b r i u m i s e s t a b l i s h e d between the two phases. Thus the f i n a l composition of the two o u t l e t phases w i l l be on the opposite ends of a t i e - l i n e i n the two phase r e g i o n . A m a t e r i a l balance f o r the o p e r a t i o n i s F + S = E + E = M = 200 l b s . 1 M, r e p r e s e n t i n g the mixture of feed and s o l v e n t , i s i n the t w o - l i q u i d phase r e g i o n as i n d i c a t e d on Fi g u r e 35, and i s common to both i n l e t and o u t l e t streams. I t s l o c a t i o n can be determined g r a p h i c a l l y on l i n e FS through the r e l a t i o n s h i p I n l e t water feed to be e x t r a c t e d , F l b s . O u t l e t ketone phase E l b s . 102 F = MS S f l .*. l i n e MS = l i n e I M Since the mixer i s an i d e a l stage, e q u i l i b r i u m i s e s t a b l i s h e d , and the two phase mixture M produces an o u t l e t water phase and an o u t l e t ketone phase R and E r e s p e c t i v e l y , the compositions of which are l o c a t e d on the ends of the t i e - l i n e through p o i n t M. The exact l o c a t i o n s of p o i n t s R and E on F i g u r e 55 were determined g r a p h i c a l l y by t r i a l - a n d - e r r o r t i e - l i n e i n t e r p o l a t i o n s . The r e s p e c t i v e magnitudes of R and E may be computed g r a p h i c a l l y by: R _ EM 8 . 3  E = RM = 8 ' 6 i . e . R = 0 .965 E 2 S u b s t i t u t i n g E quation 2 i n t o Equation 1 to solve f o r E we get 0.965E + E = 200 E = 102 l b s . R = 200 - 102 = 98 l b s . The f i n a l compositions of R and E can be read from Figure 55 and were found t o be as f o l l o w s T r y b a l , R.E., L i q u i d E x t r a c t i o n , McGraw-Hill Book Company, Inc. , New York, F i r s t E d i t i o n , Second Impression, p - 2 3 , 1951. O u t l e t water phase ( 9 8 l b s . t o t a l ) MIBK 1.7% = 1.67 l b s . Water 9 5 . 3 % = 9 3 . 3 9 l b s . A c e t i c A c i d 3.0% = 100.0% 1 .94- l b s . 9 8 l b s . O u t l e t ketone phase (102 l b s . t o t a l ) MIBK 9 5-0% 9 6 . 9 : l b s . Water 3.0% 3.06 l b s . A c e t i c A c i d 2.0% 100.0%- 2.04 l b s . 102 l b s . A summary of the r e s u l t s appears i n Table X I I I . I t should be noted t h a t the f i n a l composition of both o u t l e t streams from the spray column u s u a l l y never reached the composition of the o u t l e t streams g i v e n here. That i s the p o s i t i o n s of p o i n t s R and E f o r the experimental work say R' and E 1 would be somewhere between P and R, and E and S r e s p e c t i v e l y . These f i n a l compositions would be c l o s e r t o the i n i t i a l compositions than i s t r u e i n the example. Prom Table X I I I i t can be seen t h a t i n the water phase stream, f o r the i d e a l stage, a n e g l i g i b l e amount of t r a n s f e r occurs other than the t r a n s f e r of a c e t i c a c i d . The same can be s a i d f o r the ketone phase stream. Por the a c t u a l column o p e r a t i o n the t r a n s f e r of m a t e r i a l , other than t h a t of a c e t i c a c i d , would be somewhat l e s s than what has been c a l c u l a t e d here and ver y much l e s s f o r the p i s t o n samples. Table XIII Summary of Results JTor Sample C a l c u l a t i o n No. 7 Water Phase Ketone Phase l b s . l b s . Inlet Outlet Inle t Outlet P R S E Acetic; Acid 4.3 2.94 0.8 2.04 Water" 94.0 93-39 2.5 3.06 MIBK 1.7 1.67 96.7 96.90 100.0 98.0 100.0 102.0 105 I t i s t h e r e f o r e concluded t h a t the volume changes corresponding to these weight changes are n e g l i g i b l e because of the d i l u t e c o n c e n t r a t i o n s of a c e t i c a c i d and the s m a l l change i n mutual s o l u b i l i t y of water and ketone i n the r e g i o n under c o n s i d e r a t i o n . 

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