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Consolidation of sand formation using Freon-11 gas hydrate Cheng, Wai Keung 1975

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CONSOLIDATION OF SAND FORMATION USING  FREON-11  GAS HYDRATE by  WAI  KEUNG  CHENG  B. E n g . , M e M a s t e r U n i v e r s i t y , 1 9 7 2  A THESIS THE  SUBMITTED  IN PARTIAL FULFILMENT  REQUIREMENTS MASTER  in  FOR T H E D E G R E E OF  OF A P P L I E D  SCIENCE  the Department of  CHEMICAL ENGINEERING  We a c c e p t t h i s req u i r e d  THE  thesis  as c o n f o r m i n g  to th  standard  U N I V E R S I T Y OF B R I T I S H  May,  1975  COLUMBIA  In p r e s e n t i n g t h i s  thesis  an advanced degree at  further  for  freely  of  the  requirements  B r i t i s h Columbia, I agree  available  for  t h a t p e r m i s s i o n for e x t e n s i v e copying o f  this  representatives. thesis for  It  financial  gain s h a l l  of  The U n i v e r s i t y of B r i t i s h Columbia  2075 Wesbrook Place Vancouver, Canada V6T 1W5  Date  that  this  thesis or  i s understood that copying or p u b l i c a t i o n  written permission.  Department  for  r e f e r e n c e and study.  s c h o l a r l y purposes may be granted by the Head of my Department  by h i s of  agree  fulfilment  the U n i v e r s i t y of  the L i b r a r y s h a l l make it I  in p a r t i a l  not  be allowed without my  ABSTRACT  In t h i s s t u d y , t h e c o n d i t i o n s u n d e r w h i c h gas form i n a porous sand f o r m a t i o n were e x p l o r e d . l i s h e d t h a t t h e p e r m e a b i l i t y o f t h e s a n d may duced  by t h e g a s h y d r a t e c r y s t a l s f o r m e d Freon-11  g a s h y d r a t e was  bed i n a h i g h p r e s s u r e v e s s e l isothermal  I t was  estab-  be g r e a t l y  re-  i n the pores.  formed  in a two-inch  of one-inch diameter  sand  under  c o n d i t i o n . !\HydrateA was • f o u n d - t o - have been r  in the pores o f sand beds of f o u r ranges of p a r t i c l e f r o m 24 m e s h t o 60 m e s h .  hydrates  formed sizes  L a b o r a t o r y t e s t s showed t h a t the  hydrate thus formed c o u l d s u s t a i n a h y d r a u l i c p r e s s u r e of 1000  p s i a a c r o s s the two-inch  bed.  A s u b c o o l i n g o f a b o u t 5 ° C was  r e q u i r e d f o r the  h y d r a t e t o f o r m i n sand p o r e s and e l i m i n a t e i t s p e r m e a b i l i t y . The h y d r a t e m e l t e d a t i t s c r i t i c a l  temperature which  was  higher than i t s n u c l e a t i o n temperature. The t i m e r e q u i r e d f o r the h y d r a t e c r y s t a l to a s i z e l a r g e enough to b l o c k the p o r e s o f the bed a b o u t two  hours.  In p r a c t i c e , t h i s w o u l d  allow  to grow was  sufficient  t i m e f o r t h e h y d r a t e f o r m i n g a g e n t t o be f o r c e d t o a l a r g e a r e a f r o m one  injection point.  ii  The  amount o f h y d r a t e f o r m i n g  agent  r e q u i r e d t o b l o c k t h e s a n d p o r e s was  mately  t h a t c a l c u l a t e d from the i d e a l  found  composition  t o be of  approxi-  the  hydrate. The  r e s u l t o f t h i s s t u d y shows t h a t the  f o r m a t i o n process i n pores of a sand  bed behaved  by t h e t h e r m o d y n a m i c p r o p e r t i e s o f t h e h y d r a t e . o n l y Freon-11 gas  h y d r a t e was  hydrate former or mixture for this ditions  used  hydrate as p r e d i c t e d Thus,  i n t h i s s t u d y , any  o f h y d r a t e f o r m e r s may  although other  be s e l e c t e d  use i f t h e i r t h e r m o d y n a m i c p r o p e r t i e s match the i n the porous  formation.  con-  TABLE OF CONTENTS  Page ABSTRACT  i i  L I S T OF T A B L E S  v i i  L I S T OF F I G U R E S  i x  ACKNOWLEDGMENTS  x i i  Chapter 1  INTRODUCTION  1  2  L I T E R A T U R E REVIEW  3  2.1  Gas H y d r a t e  3  2.1.1  Gas H y d r a t e as a C l a t h r a t e Compound  2.1.2  S t r u c t u r e o f Gas H y d r a t e s  ...  5  2.1.3  C o m p o s i t i o n s o f Gas H y d r a t e s . .  9  2.1.4  Conditions f o r the Formation of Gas H y d r a t e s  2.1.5  3  S t a b i l i z a t i o n o f Gas H y d r a t e s by " H e l p " G a s e s a n d F o r m a t i o n of Double Hydrates  12 1  6  2.1.6  Effect of Salt Concentration on C r i t i c a l D e c o m p o s i t i o n T e m p e r a t u r e o f Gas H y d r a t e s . . 17  2.1.7  Kinetics of Formation of Gas H y d r a t e s  22  2.1.8  Industrial Hydrates  23  iv  Use o f Gas  Chapter  Page 2.2  Flow o f F l u i d Through Media  Porous  24  2.2.1  P r e d i c t i o n o f P r e s s u r e Drop A c r o s s P a c k e d Bed  24  2.2.2  Parameters o f Packed Bed. ...  26  2.2.3  Blocking of Pores i n Porous Media  2.3 3  Artificial  28  Freezing of Soil  C O N S O L I D A T I O N OF POROUS M E D I A GAS H Y D R A T E S 3.1 P r § v i o u s ^ S t u d i e s  28  USING 30  ;  3.2 4  Purpose of this Study  31  EXPERIMENTAL APPROACH . . . .  32  4.1  C h o i c e o o f H,HydrraiteFHo.rcmer  32  4.2  Choice of Porous Formation  35  4.3  Plan f o r Experimental Study  35  4.4  Equipment  38  4.5  Procedure  46  4.5.1 4.5.2 4.5.3 5  3 0  The Main P r o c e d u r e f o r Sand C o n s o l i d a t i o n C o n t r o l and Measurement o f Concentration . Measurement o f P o r o s i t y  R E S U L T S AND D I S C U S S I O N S  ....  46 47 48 50  5.1  H y d r a t e F o r m a t i o n i n Sand  50  5.2  E f f e c t o f Bath Temperature.  55  5.3  Crystal  60  Growth  v  Period  Chapter  Page 5.4  E f f e c t o f Sand S i z e  5.5  E f f e c t o f Hydrate Former Concentration.  5.6  E f f e c t o f Volume o f E m u l s i o n Used  5.7  Possible  5.8  Application Porous  62  ....  Effect of Pressure  .  64 66 73  to the Consolidation  of  Formation  73  6  SUMMARY AND C O N C L U S I O N  76  7  RECOMMENDATIONS  79  FOR F U R T H E R S T U D Y  REFERENCES  80  NOMENCLATURE  87  APPENDICES A  Summary o f P r o p e r t i e s  o f Common  Hydrates  and H y d r a t e Formers B C D E F  - Specifications  of^Equipment  C^T C a l i b r a t i o n s  102 .104  r . Calculation of-Ideal"Composi tion of Freon-11 Hydrate C?. 'IC a il e Ci 1 a t i . o n o f ' " P o r o s i t y d a n d Permeability Factor ' Exp E x p e K rne h t § 3: D a t a ii  89  t  vi  108 109 117  LIST OF TABLES  Table I II  III  IV V VI  VII VIII IX X XI  Page Physical  Properties of Hydrate L a t t i c e  8  Examples o f Hydrate o f Type IS t r u c t u r e t o g e t h e r with M o l e c u l a r Diameters and Lattice Constants. . . . .  10  Examples o f Hydrates o f Type II S t r u c t u r e t o g e t h e r with M o l e c u l a r Diameters and L a t t i c e Constants  11  Effect of Salt Concentration i n Various Hydrate Systems.  20  P r o p e r t i e s o f Freon-11  36  and I t s Hydrate  V a r i a t i o n o f Amount o f Freon-11 i n F i v e R e p l i c a t e Measurements o f Emulsion Concentration  48  Amount o f Freon-11 t h e S.and B e d  71  Required to Block  P r o p e r t i e s o f Common H y d r a t e Agents  Forming  P r o p e r t i e s o f Common G a s H y d r a t e s .  90 97  P o r o s i t y and P e r m e a b i l i t y F a c t o r o f Sand Beds  116  Data f o r P o r o s i t y Measurement 24-32 Mesh)  118  vi i  (Sand S i z e =  Table  Page  N  XII  Data f o r P o r o s i t y Measurement (Sand S i z e = 32-42 Mesh)  119  XIII  Data f o r P o r o s i t y Measurement (Sand S i z e = 42-48 Mesh)  120  XIV  Data f o r P o r o s i t y Measurement (Sand S i z e = 48-60 Mesh)  121  XV  Data f o r C o n s o l i d a t i o n S i z e = 24-32 Mesh)  Test  (Sand  122  XVI  Data f o r C o n s o l i d a t i o n S i z e = 32-42 Mesh)  Test  (Sand  XVII  Data f o r C o n s o l i d a t i o n S i z e = 42-48 Mesh)  Test  (Sand  XVIII  Data f o r C o n s l i d a t i o n S i z e = 48-60 Mesh)  Test  viii  (Sand  123 125 126  LIST OF FIGURES  Figure , 1  Page The p e n t a g o n a l d o d e c a h e d r o n ( b ) , f o u n d i n c o o r d i n a t i o n with the 14-face t e t r a h e d r a (a) and t h e 1 6 - f a c e h e x a d e c a h e d r a l ( c ) i n gas h y d r a t e o f t y p e I and t y p e II s t r u c t u r e respectively. .  5  2  The s t a c k i n g o f d o d e c a h e d r a of type I s t r u c t u r e  in  6  3  The s t a c k i n g o f d o d e c a h e d r a type II s t r u c t u r e  in hydrates  4  Pressure-temperature diagram f o r a system of w a t e r and h y d r a t e f o r m i n g a g e n t w i t h h y d r a t e forming agent present in excess of hydrate requirements.  5  Phase diagram  hydrates of  of Freon-21-H 0-NaCl-system  7  14  . . . .  2  S p h e r i c i t y as a f u n c t i o n o f p o r o s i t y f o r random-packed beds of u n i f o r m - s i z e d o a r t i c p a r t i c l es .  18  6  7  Phase diagram of Freon-11-water water present in excess  8  Flow diagram study  9  Arrangement study  10  S t r u c t u r e of high pressure c e l l  of Equipment of equipment  ix  system  with  for Consolidation for consolidation  27 34 39 .  4 U  41  Figure  Page  11  Parts of high pressure cell  42  12  H i g h p r e s s u r e c e l l shown immersed i n the constant temperature bath  44  C o o l i n g c u r v e o f s a n d bed w i t h gas hydrate forming in pores (bath temperature = 1°C)  51  13  14  15  C o o l i n g c u r v e o f sand bed w i t h o u t hydrate forming i n pores (bath temperature = 1°C)  gas 52  C o o l i n g c u r v e of sand bed w i t h gas hydrate forming in pores (bath temperature = 3°C)  54  16  C o r e o f s a n d b l o c k e d by g a s formed in pores  56  17  gas h y d r a t e c r y s t a l s of sand bed  18  E f f e c t o f t e m p e r a t u r e on t h e f o r m a t i o n of gas h y d r a t e i n sand pores  58  E f f e c t o f t e m p e r a t u r e i n c r e a s e on t h e b l o c k a g e o f s a n d b e d by g a s h y d r a t e s .  59  20f  E f f e c t of ilength of c r y s t a l on b l o c k a g e o f p o r e s  61  21  E f f e c t o f s a n d s i z e on b l o c k a g e o f p o r e s  63  22  E f f e c t of c o n c e n t r a t i o n of Freon-11 in e m u l s i o n on t e m p e r a t u r e r e q u i r e d f o r h y d r a t e f o r m a t i o n and b l o c k a g e o f p o r e s  65  E f f e c t of c o n c e n t r a t i o n of Freon-11 in e m u l s i o n on b l o c k a g e o f p o r e s o f s a n d bed o f s i z e 32-42 mesh  67  . SI 9  23  hydrate  formed in pores  x  growth  period  56  Fi gure 24  Page E f f e c t o f c o n c e n t r a t i o n o f Freon-11 i n e m u l s i o n on t h e b l o c k a g e . o f p o r e s o f s a n d b e d o f s i z e 42-48 mesh  68  25  Amount o f e m u l s i o n r e q u i r e d t o b l o c k the sand f o r m a t i o n  69  26  E f f e c t o f F r e o n - 1 1 c o n c e n t r a t i o n on amount o f emulsion r e q u i r e d  70  27  C a l i b r a t i o n curve o f Irpn=G6nstantan«, „ , thermocouples (reference point - 0°C)  105  28  Calibration  curve of rotameter  106  29  Calibration  curves of pressure trandsucer ....  107  30  P o r o s i t y o f sand bed ( s i z e = 24-32 mesh)  110  31  P o r o s i t y o f sand bed ( s i z e = 32-42 mesh)  I l l  32  P o r o s i t y o f sand bed ( s i z e = 42-48 mesh)  112  33  P o r o s i t y o f sand bed ( s i z e = 48-60 mesh)  113  34  Darey's  permeability factor  xi  o f sand beds.  . . . .  115  ACKNOWLEDGMENTS  The a u t h o r w i s h e s the (1)  to extend his g r a t i t u d e towards  f o l l o w i n g p e o p l e and o r g a n i z a t i o n s :  Dr. K.L.  P i n d e r f o r h i s w i s e and c o n s i d e r a t e  s u p e r v i s i o n and g u i d a n c e t h r o u g h o u t course of this  (2)  the  work.c  The p e r s o n n e l o f t h e C h e m i c a l E n g i n e e r i n g Department workshop f o r t h e i r c o o p e r a t i v e a s s i s t a n c e i n e q u i p m e n t c o n s t r u c t i o n and mai n t e n a n c e .  (3)  National Research C o u n c i l of Canada, Department of Mines, Energy & Resources, M i n e s B r a n c h and The U n i v e r s i t y o f Columbia this  for their financial  work.  xi i  British  support of  Chapter 1  INTRODUCTION  G a s h y d r a t e s w e r e d i s c o v e r e d a s e a r l y a s 1811 Davy [ 1 ] , but the f a c t t h a t gases form h y d r a t e s w i t h was  n o t g e n e r a l l y known u n t i l  f i r s t documented  by  water  Hammerschmidt [2] r e p o r t e d the  problem of p i p e - l i n e f r e e z i n g  in the n a t u r a l  g a s i n d u s t r y , c a u s e d by t h e f o r m a t i o n o f g a s h y d r a t e s . i n v e s t i g a t i o n r e v i v e d a s u b j e c t t h a t had been d o r m a n t  His fora  l o n g time and b r o u g h t o u t the i m p o r t a n c e o f gas h y d r a t e s to the n a t u r a l gas i n d u s t r y .  M u c h r e s e a r c h on t h e c o n d i t i o n s  o f f o r m a t i o n o f n a t u r a l g a s h y d r a t e s was  done to  determine  methods f o r the p r e v e n t i o n o f t h e s e h y d r a t e s which can c l o g oil  and gas p i p e l i n e s and e q u i p m e n t .  h a d b e e n d o n e on t h e i n d u s t r i a l r e c e n t l y , m o r e r e s e a r c h was  up  However,, n o t much work  use o f gas h y d r a t e s .  d o n e on t h e p r a c t i c a l  h y d r a t e s w h e n t h e H y d r a t e P r o c e s s was  Only  use of  gas  proposed f o r desalination  of seawater [ 3 ] . I t has been  proposed  that the hydrate of a s u i t a b l e  gas, l i q u i d or a mixture of these agents formed p r o p e r c o n d i t i o n s may  under  be u s e d t o e l i m i n a t e o r r e d u c e  p e r m e a b i l i t y of porous rock [4,5].  1  By f o r m i n g s o l i d  the the gas  2  hydrates  in water-bearing  formation will Artificial  f o r m a t i o n s , i t i s b e l i e v e d that the  be s t a b i l i z e d a n d w a t e r f l o w c a n be  f r e e z i n g of soil  the c o n s t r u c t i o n and m i n i n g t h i s method of s o i l gas of  r e s e r v o i r s may porous  [6],  an e x p e n s i v e  stopped.  p r o c e s s used  in  i n d u s t r i e s , c o u l d be r e p l a c e d b y  c o n s o l i d a t i o n . Leakage a l s o be s t o p p e d  from  underground  by r e d u c i n g t h e p e r m e a b i l i t y  r o c k by t h e f o r m a t i o n o f h y d r a t e s  in those  forma-  t i o n s [ 5 ]. The  purpose  of t h i s study i s to e x p l o r e the  c o n d i t i o n s f o r f o r m i n g a gas h y d r a t e  in porous  t o e s t a b l i s h t h a t t h e i r p e r m e a b i l i t y may by t h i s  method.  various  formations  and  be g r e a t l y r e d u c e d  Chapter 2  LITERATURE REVIEW  2.1  Gas  2.1.1  Hydrate  Gas  Hydrate Powell  as a C l a t h r a t e Compound [ 7 ] was  compounds i n t o a group structural  analysis.  the " g u e s t s . "  or cages  and  The  formed  formation  crystalthe  is retained in closed  cavities [8-12].  l a t t i c e of the  o r a t o m i s c o n s i d e r e d a s an  host unit  of the c l a t h r a t e s i s not a chemical  the complete  s t r u c t u r e formed another  e n c l o s u r e o f one m o l e c u l e  by a n o t h e r .  by v a n  "host"  l a t t i c e of the "host"  by t h e c r y s t a l  molecular  x-ray  components of these c l a t h r a t e s are a s s o c i a t e d with  other through  one  "guest"  p r o v i d e d by t h e c r y s t a l  The  on  or more d i s t i n c t components:  i t s enclosed molecule  cell.  of  A clathrate is a single-phased  The  G e n e r a l l y , a cage  to c l a s s i f y a group  known as " c l a t h r a t e s , " b a s e d  l i n e s t r u c t u r e o f two and  the f i r s t  The m o l e c u l e s  der Waal's f o r c e s and  formed  will  3  the  London's d i s p e r s i o n  s t r u c t u r e may  n o t be  retain only  or atoms t h a t are w i t h i n a d e f i n i t e range  each  i n t e r a c t with  forces [ 7 ] . Since a crystalline e a s i l y , a p a r t i c u l a r cage  by  reaction.  de-  molecules  o f s i z e s and  shapes  4 determined  by t h e s i z e o f c a g e and  walls [11,12].  Furthermore,  the opening  chemical  of  cage  stoichiometry is  i n a p p l i c a b l e to c l a t h r a t e compounds, s i n c e empty cages occur in c e r t a i n crystal  lattices  [11].  may  Instead, clathrates  a r e u s u a l l y d e s i g n a t e d by a m a x i m u m - c o m p o s i t i o n f o r m u l a nOmM; where C and  M a r e h o s t and g u e s t components  t i v e l y , n i s the number o f C m o l e c u l e s  accommodated i n a s i n g l e cage  respec-  per u n i t cage  and m i s t h e maximum number o f M m o l e c u l e s  of  cell  that could  be  [11].  C u r r e n t l i t e r a t u r e on g a s h y d r a t e s r e c o g n i z e s t h a t gas h y d r a t e s a r e n o n - s t o i c h i o m e t r i c c l a t h r a t e compounds [8-12,14]. Gas  hydrates are s o l i d c r y s t a l l i n e  the appearance  o f snow o r l o o s e i c e .  t h a t c h l o r i n e and w a t e r Because gas  salination  with  discovered [1].  hydrates f o r the n a t u r a l  f o r the hydrate p r o c e s s of water  [ 3 ] , a l a r g e number o f a g e n t s  form gas h y d r a t e s w i t h water The  Davy f i r s t  form a s o l i d gas h y d r a t e  o f t h e r e s e a r c h on g a s  i n d u s t r y [ 1 3 ] and  substances  under  a r e now  a wide range  de-  known t o °'f c o n d i t i o n s .  l i t e r a t u r e on t h e t h e r m o d y n a m i c p r o p e r t i e s o f g a s  hydrates  is voluminous.  H o w e v e r , 1 i t e r a t u r e on t h e m e c h a n i s m  of  f o r m a t i o n and  t h e k i n e t i c d a t a on f o r m a t i o n o f h y d r a t e s  is  scarce. Only a b r i e f o u t l i n e of the l i t e r a t u r e w i l l attempted  here.  Byk  and  Fomina [14] have g i v e n a v e r y  r e v i e w o f t h e l i t e r a t u r e on gas  hydrates.  Suwandi  [12]  be good has  5 tabulated  some 51 g a s h y d r a t e s w i t h t h e p r o p e r t i e s o f t h e  h y d r a t e s and t h e agents  themselves.  Other  useful references  on t h e p r o p e r t i e s o f h y d r a t e s a r e t h o s e by t h e U.S. O f f i c e of S a l i n e Water  2.1.2  [16,17].  S t r u c t u r e o f Gas Several  hydrate  p o l a r a n d some w e a k l y called  Hydrates s t r u c t u r e s a r e known b u t m o s t n o n -  p o l a r gases  I and II [ 1 8 ] . These  by C l a u s s e n  f o r m o n e o f t h e two s t r u c t u r e s  two s t r u c t u r e s w e r e e l u c i d a t e d  [19,20],  P a u l i n g and Marsh [ 2 1 ] , von S t a c k e l b e r g  [22], and Mendelcorn  [ 1 1 ] . In b o t h o f t h e s e s t r u c t u r e s , t h e  basic unit s t r u c t u r e i s a pentagonal This polyhedron oxygen  i s c o m p o s e d o f 20 w a t e r  a t the apex and hydrogen  belonging to the adjacent  F i g u r e 1.  (Figure l b ) .  molecules, with the  bonded to f o u r other  atoms, three i n the given polyhedron  (a)  dodecahedron  and the remaining  oxygen one  polyheron.  (b)  (c)  The pentagonal dodecahedron ( b ) , found i n c o o r d i n a t i o n with the 14-face t.etradecahedra (a) and t h e 16 f a c e h e x a d e c a h e d r a (c) i n gas hydrate o f type I and type II s t r u c t u r e r e s p e c t i v e l y [ 9 ] .  6  In  the type I s t r u c t u r e , the pentagonal  dodecahedron  is stacked together with a tetradecahedra (Figure l a ) having 12 p e n t a g o n a l  a n d two h e x a g o n a l  t u r e i s s h o w n i n F i g u r e 2.  faces.  The r e s u l t i n g  struc-  Each o f these c e l l s has a c e l l  o  c o n s t a n t o f 12 A . cell  T h e r e a r e 46 m o l e c u l e s o f w a t e r  per unit  a n d e i g h t c a g e s w h e r e h y d r a t i n g m o l e c u l e s may b e l o c a t e d ;  i n c l u d i n g two s m a l l c a g e s a n d s i x l a r g e c a g e s . cages a r e r e g u l a r pentagonal  dodecahedra  The small  w i t h mean f r e e  o  d i a m e t e r o f 5.1 A a n d e a c h c a n r e t a i n o n e m o l e c u l e s u c h as a r g o n , h y d r o g e n s u l p h i d e o r m e t h a n e . T h e l a r g e r v o i d s a r e o  t e t r a h e d r a w i t h m e a n f r e e d i a m e t e r o f 5.8 A ; e a c h c a n r e t a i n one m o l e c u l e o f e t h a n e ,  F i g u r e 2.  sulphur dioxide or chlorine.  The s t a c k i n g o f dodecahedra type I s t r u c t u r e[ 9 ] .  In  i n hydrates of  the type II s t r u c t u r e , the dodecahedra  are slightly  deformed  s o t h a t t h e two o p p o s i t e m o l e c u l e s a r e e x a c t l y t e t r a -  hedral.  T h e s e two t e t r a h e d r a l p o i n t s a r e t h e n  superimposed  on t h e p o s i t i o n s i m i l a r t o p a i r s o f c a r b o n a t o m s i n a d i a m o n d lattice.  This leads to the stacking o f dodecahedra  to form a  7 cubic s t r u c t u r e with a cell with hexadecahedral  c a v i t i e s which  h e x a g o n s a n d 12 p e n t a g o n s  F i g u r e 3.  c o n s t a n t o f 17 A ( F i g u r e 3 ) , a n d a r e c o n s t r u c t e d from  four  ( F i g u r e l c ) . T h e r e a r e 136 w a t e r  The s t a c k i n g o f dodecahedra 11 s t r u c t u r e [ 9 ] .  molecules per unit c e l l , each o f which  i n hydrate o f type  c o n t a i n s 16 d o d e c a h e d r a l  o  v o i d s o f mean f r e e d i a m e t e r o f , 5 A a n d e i g h t  hexadecahedra  o  o f m e a n f r e e d i a m e t e r o f 6.7 A . Table  I summarizes the p h y s i c a l p r o p e r t i e s o f  hydrate l a t i c e s o f s t r u c t u r e I and I I . Whether the hydrate i s o f t y p e I o r t y p e II s t r u c t u r e depends upon t h e d i m e n s i o n s , M i . e . t h e e f f e c t i v e mean d i a m e t e r . ( d ^ ^ ) o f t h e g u e s t e  In g e n e r a l , f i v e d i f f e r e n t M  (i)  For d  g f f  molecule.  s t r u c t u r e s c a n be o b t a i n e d :  °  < 5.1 A , t y p e I s t r u c t u r e w i l l  with a l l e i g h t cages  2  and h y d r o g e n  formed  f i l l e d . a n d w i t h a maximum  c o m p o s i t i o n formula o f M*5.75H 0. of hydrate formers  be  Examples  of t h i s s t r u c t u r e a r e methane  sulphide.  8  Table I Physical  Properties  of Hydrate  Lattice  Structure Maximum C o m p o s i t i o n  Formula  I  Structure  M-5 , 7 5 H 0 M-7. 7 H 0 .6M .46H 0  M-17H 0 Mj.2M -17H 0  2  2  2  2  2  Lattice Constant A No. o f W a t e r unit cell  (ii)  Diameter  17  12  136  46  cell  o  Cell  A  F o r 5.1 A° < d ffM  Smal 1  Large  Smal 1  Large  2  6  16  8  5.1  5.8  5  < 5.8 A°, t y p e I s t r u c t u r e  Q  be f o r m e d  2  2  Molecules/  No. o f C a g e s / u n i t  with only  6 large cages  a maximum-composition formula of  filled  6.7  will  and with  M«7.7H 0. 2  Examples o f hydrate former o f t h i s s t r u c t u r e a r e bromine,  (iii)  c h l o r i n e , and sulphur  For a mixture M  2  where d ^  ° f  dioxide.  o f two t y p e s o f m o l e c u l e s  M  °  a type I s t r u c t u r e mixed  six l a r g e r cages  hydrate will  two s m a l l e r  cages  Mi and  M  < 5.1 A a n d 5.1 A < d |  w i t h Mi f i l l i n g  II  °  < 5.8 A ,  f  be  and M  giving a formula of  2  formed filling  9  An example o f t h i s mixed  2M!•6M2•46H20.  hydrate  is  2H2S-6C2H6-46H20.  °  (iv)  For  with eight  o f two  e  f  O  < 5 A and  IIstructure  w i t h Mi f i l l i n g 6M-i  this  Freon-12,  are  f  < 6 . 7 A , a •-  cages  tabulated  1  -M2  • 1 7H20'".  2H 2 S • C 3 H 8 • 1 7H 2 0  i n T a b l e II and  molecular diametar  2.1.3  Compositions  and M l f i l l i n g  Examples o f or  The tion  experimental  2CHit«C3H8*17H20.  I and I I  III t o g e t h e r with the  and l a t t i c e  o f Gas  be formed  giving a formula o f  o r 2M  *8M2-1 36H20  O  hydrate will  16 s m a l l e r  l a r g e r cages  structure  5 A < d^  mixed  Mi a n d  M  A summary o f e x a m p l e s o f h y d r a t e s o f s t r u c t u r e is  with a  propane  types of molecules  O  M 2 w h e r e d' '*  1  f i l l e d , and  is  iodide.  M  eight  I Istructure  Examples o fhydrate o f  are Freon-11,  For a mixture  type  larger cages  17H20.  structure  and methyl (v)  •  A, type  < 6.7  Q  formula o fM this  °  A < d ff  5.0  formed  M  agent  constant.  Hydrates determination o fhydrate  composi-  i s d i f f i c u l t and e a r l y r e s u l t s o b t a i n e d b y v a r i o u s  investigations  are d i f f e r e n t in s i g n i f i c a n t  amounts. F o r  10  Table II Examples  o f Hydrates of Type I S t r u c t u r e T o g e t h e r with Molecular Diameters and Hydrate Constants  Guest Molecule, M  Molecular Diameter o f M, A  Lattice Constant A 0  4.70  12.04  N 0 2  4.95  12.03  Xe  4.40  11 .97  H S  4.10  12.00  H Se  4.40  12.06  CH C1 3  5.06  12.00  S0  2  5.00  11.94  5.17  12.03  CH B r  5.33  12.09  Br  5.68  12.01  C0  2  2  2  Cl  2  3  2  Table III Examples  o f H y d r a t e s o f Type II S t r u c t u r e T o g e t h e r w i t h M o l e c u l a r D i a m e t e r s and L a t t i c e C o n s t a n t s  Guest Molecule, M  Molecular Djameter o f M, A  Lattice Constant A  (CH ) 0  6.06  17 .44  (CH ) CH 3  6.50  17.53  C H C1 5  6.20  1 7. 30  CH2CI.2  6.08  17.31  CHCI.3  6.44  17.30  3  3  2  2  Q  12  example, propane  hydrate  to 17.95 moles o f water difficulties caused  i n the determination o f hydrate  decomposing,  tration  contamination formed  o f water.  from  composition,  solution  al.  the propane-water  water  which  system.  at the site of crystal  hydrate agglomerate.  2.1.4  al.  Galloway.et  t h e problem  Marshall  studied  [26]developed  a  of occlusion of liquid  c r y s t a l . b y grinding and crushing the The e f f e c t o f p r e s s u r e on t h e composi[ 2 6 ] a n d G o u g h et  Saito studied the composition  C o n d i t i o n f o rt h e Formation  al.  o f various Freons f o r  i n t h e d e - m i n e r a l i z a t i o n o f seawater  The  determination  f o rthe study o f hydrate  t i o n was a l s o s t u d i e d b y G a l l o w a y  use  to the direct  growth  a t high pressure while Ceccoti studied  approach  avoided  i n the hydrate  [27].  i s a f f e c t e d by t h e concen-  [24] and Ceccoti [25].  different experimental  sample  t h e more p r e c i s e s t u d i e s a r e t h o s e  the methane-water system  composition  composition are  Further, the composition  O f t h e many s t u d i e s d e v o t e d  o f M a r s h a l l et  The  i n handling the hydrate without i t  of the guest molecules  of hydrate  [23],  and by t h e d i f f i c u l t y o f o b t a i n i n g a pure  of a hydrate  [11].  p e r u n i t mole o f propane  by t h e problems  without  h a s b e e n r e p o r t e d t o c o n t a i n 5.8  [28].  o f Gas Hydrate  conditions f o rthe formation of hydrates  according to the equation M + nH 0 C M-nH 0 2  2  (1 )  13  a r e shown i n t h e phase d i a g r a m  ( F i g u r e 4) o f t h e  heterogeneous  e q u i l i b r i u m on p r e s s u r e - t e m p e r a t u r e c o o r d i n a t e s In t h i s d i a g r a m ,  the r e g i o n s , in which  [14,23,29-32],  the gas h y d r a t e  f o r m , a r e l o c a t e d to the l e f t o f c u r v e s I I , I I I and The  intersection  of the system,  of II and  p o i n t f o r the d e c o m p o s i t i o n  o f t h e h y d r a t e ; a t t h i s p o i n t , B, h y d r a t e +  + water c o e x i s t .  Depending  the temperature  c u r v e I I ) o r i n t o two  The phase  field.  (#,)  +  +  u p o n t h e s y s t e m p r e s s u r e , on either  of the hydrate former  liquid  of the hydrate former  have been  M  hydrate + ice "M(g)  the hydrate w i l l  i n t o w a t e r and gas phase  phase  +  The i n t e r s e c t i o n o f II and I I I g i v e s the  "lower quadruple p o i n t , " C at which  raising  IV.  IV, t h e "upper q u a d r u p l e p o i n t "  i s the c r i t i c a l  water c o e x i s t .  will  phases  decompose (on  - water and  crossing  liquid  (on c r o s s i n g c u r v e I I I ) .  diagrams o f a l a r g e number o f h y d r a t e s  s t u d i e d e x p e r i m e n t a l l y by v a r i o u s w o r k e r s  R o b e r t s et  al.  in this  [33] s t u d i e d the phase diagram  h y d r a t e s o f methane and e t h a n e .  F r o s t and Deaton  of  [34] i n -  v e s t i g a t e d a number o f n a t u r a l gas h y d r a t e s i n c l u d i n g of c a r b o n d i o x i d e , methane, e t h a n e and p r o p a n e . .  those  Wilcox,  C a r s o n and K a t z [ 3 5 ] s t u d i e d t h e p h a s e d i a g r a m o f some natural  gas h y d r a t e s .  C h i n w o r t h and K a t z [ 3 1 ]  determined  e x p e r i m e n t a l l y the phase  d i a g r a m f o r h y d r a t e s o f some  e r a n t s , namely Freon-11,  Freon-12,  and s u l p h u r d i o x i d e .  S e l l e c k et  behaviour in the hydrogen  al.  Freon-22,  methyl  chloride  [36] s t u d i e d the  sulphide-water system.  refrig-  phase  Wittstruck  T E-MPERAT Figure  4.  URE  P r e s s u r e - t e m p e r a t u r e d i a g r a m f o r a system o f water and hydrage agent with hydrate forming agent present in excess of hydrate composition.  forming  15 [ 3 2 ] i n v e s t i g a t e d t h e p r o p e r t i e s o f some h a l o m e t h a n e s . et  al.  bromide,  [23] presented Freon-21  his co-workers  the thermodynamic p r o p e r t i e s o f methyl  and Freon-31  [24,37]  in detail.  Kobayshi  and  s t u d i e d some h y d r a t e s f o r m e d  presures i n c l u d i n g methane, argon K a t e l a a r [ 3 8 ] s t u d i e d t h e phase system.  and n i t r o g e n  diagram  a t high  hydrates.  of the chlorine-water  T e s t e r and Wiegandt [39] s t u d i e d the b i n a r y  c h l o r i d e - w a t e r system, the t e r n a r y methylene  binary chloroform-water  temperature  Theoretical  system  chloride-chloroform-water  They a l s o showed t h a t t h e p r e s e n c e decomposition  Barduhn  and  system.  o f hexane w i l l  of the methylene  methylene  lower the  chloride hydrate.  s t u d i e s o f the p r o p e r t i e s and c o n d i t i o n s  o f f o r m a t i o n have a l s o been  o f i n t e r e s t t o many i n v e s t i g a t o r s .  W i c o x et  K-factors charts to predict  al.  [35] presented  hydrate formation i n n a t u r a l gas mixtures.  However,  of t h e i r e m p i r i c a l b a s i s , these charts can give r e s u l t s f o r c o n d i t i o n s o t h e r than those used  because  erroneous  to prepare  them [ 1 8 ] . The statistical  r e g u l a r s t r u c t u r e o f gas hydrates  allows  thermodynamic study of t h e i r p r o p e r t i e s .  der Waals and Platteeuw  [40] derived the basic  using the Lennard-Jones-Devonshire the d i s s o c i a t i o n  cell  model  Van  equations to c a l c u l a t e  preesure o f nine gas hydrates a t 0°C.  McKay and S i n a n o g l u [ 4 1 ] c a l c u l a t e d d i s s o c i a t i o n for eight polyatomic gases.  Kobayashi  [24,37,42,43] obtained the Lennard-Jones  and h i s  pressures co-workers  12-6 p o t e n t i a l s  16 based  on t h e i r e x p e r i m e n t a l d a t a f o r h y d r a t e s o f m e t h a n e ,  argon and n i t r o g e n . a potential cell.  They used t h e K i h a r a model t o d e v e l o p  function f o rrod-like molecules  T h e model was f o u n d  to t h e i r e a r l i e r e x p e r i m e n t  encaged  in a  t o be f a i r l y a c c u r a t e when c o m p a r e d data.  a p p l i e d to the t e r n a r y system o f  T h e model was f u r t h e r  methane-nitrogen-water.  P a r r i s h and P r a u s n i t z [ 1 8 ] used van d e r  Waals-Plateeuw  theory with the Kihara s p h e r i c a l - c o r e potential  to study  fifteen  their  hydrate forming gases and then extended  study  to mixtures o f h y d r a t e - f o r m i n g and non-hydrate-forming T e s t e r et sampling  al.  [ 4 4 ] used a Monte C a r l o approach  gases.  of statistical  t o e v a l u a t e t h e d i s s o c i a t i o n p r e s s u r e o f a mono-  v a r i a n t three phase ( i c e - s o l i d c l a t h r a t e - w a t e r ) system. A s u m m a r y o f t h e p r o p e r t i e s o f common g a s h y d r a t e s is given i n Appendix  2.1.5  A.  S t a b i l i z a t i o n o f Gas H y d r a t e Formation  o f Double  by " H e l p " Gas a n d  Hydrates  Some g a s e s h a v e b e e n f o u n d t o s t a b i l i z e t h e s t r u c ture o f gas hydrates [14]. decomposition  The presence o f a i r reduces the  p r e s s u r e o f t h e N 0 h y d r a t e f r o m 250 atm. t o 2  100 a t m . a t 1 4 ° C . T h e p r e s e n c e o f N , 0 2  found to decrease the decomposition  2  and C 0  temperature  2  was a l s o  of hydrates  o f C C U , CHC1 , C H C 1 . 3  2  2  Extensive i n v e s t i g a t i o n sof the s t a b i l i z a t i o n action o f t h e s e " h e l p " g a s e s w e r e made by B a r r e r , S t u a r t , R u z i c k a  17 [45,46].  They  showed t h a t gases  CH4,  K r , Xe, C h \ ,  tion  by o c c u p y i n g  C H  2  2  6  and Ruth  p r o p e r t i e s of hydrogen The most s i g n i f i c a n t  5.1  The  o f gas  0 ,  Ar,  2  2  forma-  hydrates.  [47] s t u d i e d the  sulphide in certain result  N ,  stabilizes hydrate  2  stabilization  gas i h y d r a t e s .  is that with tetrahydrofuran  decomposition  temperature  of THF*17H 0 i s 2  °C w h i l e t h a t o f H S • T H F • 1 7 H 0 i s 2 1 . 3 ° C 2  atmospheric  2.1.6  Ne,  2  the small c a v i t i e s  G l e w , Mak  hydrate.  C0  and  like H ,  2  at  pressure.  Effect  o f S a l t C o n c e n t r a t i o n on C r i t i c a l  Temperature  o f Gas  Hydrate  Much r e s e a r c h has been c o n c e n t r a t i o n on t h e c r i t i c a l gas h y d r a t e s .  Such  Decomposition  d o n e on t h e e f f e c t o f  decomposition  temperature  data were important i n hydrate  f o r d e s a l i n a t i o n of sea water  salt of  process  ( S e c t i o n 2.1.8) and a r e e q u a l l y  i m p o r t a n t when c o n s o l i d a t i n g s a l t b e a r i n g f o r m a t i o n s ( S e c t i o n Knox and Hess f i r s t  s t u d i e d the e f f e c t of sodium c h l o r i d e  c o n c e n t r a t i o n with the propane co-workers  have  hydrate  [3].  Barduhn  and  s t u d i e d t h i s e f f e c t w i t h v a r i o u s gas  his  hydrates  [15,16,23]. F i g u r e 5 shows the phase H0 2  system.  The  tion are dotted.  diagram  of Freon-21  -  NaCl  hydrate lines for v a r i o u s ; s a l t concentraThe p r e s e n c e  of s a l t i n the system  t h e e f f e c t o f s h i f t i n g t h e t r i p l e p o i n t down t h e  has  condensation  l i n e w i t h a r e s u l t a n t p a r a l l e l movement of the h y d r a t e  line.  Liquid Aqueous  F i g u r e 5 . P h a s e d i a g r a m o f F r e o n - 2 1 - H 0 - N a C l system [ 1 7 ] . 2  Freon-21  19  Table  IV s u m m a r i z e s t h e d e p r e s s i o n o f t h e c r i t i c a l  t u r e s by t h e p r e s e n c e  tempera-  of sodium c h l o r i d e in various  hydrate  systerns . The  depression of the hydrate  due  t o s a l t c o n c e n t r a t i o n may  ing  equation  n n  be e s t i m a t e d  AH ( T i - T ) RT T log a  =  from  temperature  the  follow-  2  X  where  formation  (  2  .  u ;  2  n = h y d r a t e c o m p o s i t i o n ( i . e . number o f moles of H 0 to each mole of hydrate forming a g e n t ) 2  a and  2  = a c t i v i t y of water in a s a l t s o l u t i o n p u r e w a t e r as s t a n d a r d s t a t e ,  AH = h e a t o f f o r m a t i o n o f g a s  Note t h a t ( T i - T ) 2  hydrate.  i s the d e p r e s s i o n of the  t e m p e r a t u r e a t a g i v e n p r e s s u r e due  to s a l t  It i s not the d e p r e s s i o n of the c r i t i c a l temperature which cannot The  g i v e n t e m p e r a t u r e due estimated,  concentration.  decomposition  formation  t o s a l t c o n c e n t r a t i o n may  i f the hydrate  the f o l l o w i n g  formation  be a t c o n s t a n t p r e s s u r e  depression of hydrate  composition  with  [23].  pressure at a also  be  i s known [ 2 3 ] ,  by  equation:  n  _  log(fi/f ) -log a 2  2  (3)  T a b l e IV E f f e c t o f S a l t C o n c e n t r a t i o n i n Various Hydrate Systems [15] Hydrate Forming Agent  Critical Temp. (°C)  Decomposition Pressure (mm H g )  Depression of C r i t i c a l Decomposition Temperature (°C) by t h e f o l l o w i n g wt. % o f NaCl i n S o l u t i o n 2  4  6  8  10  Propane C3H8  5.7  4140.  1 .2  .2.4  3.7  5.0  6.3  I so-Butane i -C Hi o  1 .88  1256.  1.12  2.30  3.55  4.87  6.23  Freon-12B1 CC1F Br  9.9  1272.  1 .04  2.15  3.32  4.54  5.92  Freon-21 CHCl F  8.69  761 .  1.12  2. 26  3.43  4.63  5.85  Freon-31 CH C1F  17.88  2147.  0 .97  2.01  3.09  4.24  5.53  Freon-40 CH C1  20.4  3640  1 .1  2.3  3.3  4.6  5.9  Freon-40B1 CH 3 B r  14.73  1151 .  1.15  2. 39  3.68  5.05  6.57  2  2  2  3  CONTINUED  T a b l e IV  Hydrate Forming Agent  Critical  Decomposition  Temp.  Pressure (mm Hg)  1 3.09  1 743.  Freon-152a CH CHF  14.9  Carbon C0  10.00  (°C)  Freon  142b  CH3CCIF  3  2  Dioxide  .  (Continued)  Depression of C r i t i c a l Decomposition Temperature ( ° C ) by t h e f o l l o w i n g w t . % o f N a C l i n S o l u t i o n 2  4  6  8  1.10  2.27  3.49  4.77  6.22  3270.  0.9  1.9  2.9  4.0  5.2  33744.  0.99  2.03  3.13  4.32  5.6  6390.  0.8  1.7  2.9  4.2  5.4  10  2  Chlorine Cl 2  28.3  22  where  f i = f u g a c i t y of the hydrate forming agent in the vapour phase with s a l t s o l u t i o n presen t ,  and  f2 = f u g a c i t y o f t h e a g e n t phase with pure water same t e m p e r a t u r e .  2 .1..'7  K i n e t i c s of Formation Although  o f Gas  i n the vapour p r e s e n t a t the  Hydrates  much r e s e a r c h has  been  devoted  to  the  determination of hydrate formation c o n d i t i o n s , only a s t u d i e s have been K n o x et al. propane  d o n e on t h e k i n e t i c s o f h y d r a t e  formation.  [3] i n v e s t i g a t e d the k i n e t i c s of formation  h y d r a t e and f o u n d  t h a t the hydrate f o r m a t i o n  d e p e n d s upon v e s s e l a g i t a t i o n and crystal  growth  can take p l a c e .  t h e s u r f a c e a r e a on  B a r r e r and  Ruzicka  type  II s t r u c t u r e s , and  o f h y d r a t e s o f c h l o r o f o r m and Xe a n d found  CH4.  the k i n e t i c s of  of  rate which  [48]  i n v e s t i g a t e d the k i n e t i c s of i n c l u s i o n of r a r e gases t y p e I and  few  in formation  tetrahydrofuran with Ar,  at various temperature  (-78°  and  0°C).  t h a t the ease of f o r m a t i o n depends upon the  f r a c t u r e of s u r f a c e l a y e r s of the c l a t h r a t e phases  Kr,  They continuous on  the  ice surface. Pinder [49] found  t h a t the r a t e of f o r m a t i o n  t e t r a h y d r o f u r a n h y d r a t e i s d i f f u s i o n c o n t r o l l e d and upon the degree h i s s t u d y may formers water.  of  depends  o f a g i t a t i o n . H o w e v e r , he p o i n t e d o u t  that  n o t be g e n e r a l i z e d t o o t h e r i n s o l u b l e h y d r a t e  since tetrahydrofuran is completely soluble in  23 Glew and  Haggett  [50,51]  found  formation of ethylene oxide hydrate  t h a t the r a t e of  is independent  of a g i t a -  t i o n r a t e above a c e r t a i n minimum s t i r r e r speed. c l u d e d t h a t h e a t t r a n s f e r was  They  the c o n t r o l l i n g step in  contheir  hydrate formation studies. B o l l a n s [52] r e p o r t e d t h a t the r a t e of of Freon-11  h y d r a t e d e p e n d s upon t h e r e m o v a l  c r y s t a l s from the Freon-11 agitation  2.1.8  s u r f a c e , which  theoretical  Use  o f Gas  in nature.  hydrates are scarce. industrially  of sea water  Hydrates  Reports  sea water  l i b e r a t i n g pure water.  In t h i s p r o c e s s , p r o p a n e a t 1.1°C  and  the sea water, The  3.9  atm.  gas been  hydrate  The  hydrate,  i s d e c o m p o s e d by  success of the process Each  t h e r m o d y n a m i c p r o p e r t i e s and forms  s p e c i f i c c o n d i t i o n s of temperature  heat,  depends  hydrate  former  a hydrate  and p r e s s u r e .  to the s t u d y o f a l a r g e number o f h y d r a t e s and  and  use o f gas h y d r a t e  liquid mixtures.  their  pro-  i s the s e p a r a t i o n of  B a r r e r and R u z i c k a  at  This led  [15,23,30]. Another  gaseous  use o f  Process for d e s a l i n a t i o n  upon the n a t u r e o f the h y d r a t i n g a g e n t . h a s i t s own  was  O n l y r e c e n t l y , have gas h y d r a t e s  [3,28,53,54].  from  hydrates  on t h e i n d u s t r i a l  in the Hydrate  a f t e r s e p a r a t i o n from  perties  hydrate  intensity.  Industrial  is formed  of the  i s a f u n c t i o n of  M o s t o f t h e e a r l y r e s e a r c h on g a s  used  formation  [46]  24 considered mixtures C H CH 6  5  i ndetail  of and  3  O2  and  CHCI.3,  t h e s e p a r a t i o n o f gaseous  and liquid  N ,,  K r a n d A r , Xe a n d K r , C H 3 I a n d C H C 1 ,  C H  6  2  6  3  and CHC1 , and Cl Cl3  2  2  and CHC1 . 3  Depending  on t h e d i s s o c i a t i o n p r e s s u r e s o f t h e d i f f e r e n t  hydrates,  t h e formation o f a c l a t h r a t e from mixtures  o f gases  or l i q u i d s could provide high f r a c t i o n a t i o n f a c t o r s . method c o u l d a l s o be a p p l i e d t o s e l e c t i v e removal Cl* p a r a f f i n s o r o l e f i n s f r o m  other longer chained  This  o f C and 3  hydro-  carbons [ 8 ] .  2.2  Flow o f F l u i d through  2.2.1  Porous  Prediction o f Pressure The  p r e s s u r e drop  Media  Drop a c r o s s Packed Bed  for fluid  flowing through  a fixed  bed o f g r a n u l a r p a r t i c l e s depends upon t h e r a t e o f f l u i d flow, theviscosity and density o f thef l u i d , and o r i e n t a t i o n o f t h e p a c k i n g surface o f t h ep a r t i c l e s developed a packed used packed  and t h es i z e , shape and  [55]. Various equations  t o describe t h eenergy bed.  loss i nfluid  The Carman-Kozeny equation  t o c a l c u l a t e p r e s s u r e drop beds,  flowing  been through  (equation 4) i s  f o r laminar flow  g (1 - e ) - — j — ^ = 180 -3—-z p [55] developed  p r a t i n g both  have  through  ignoring thekinetic energy'loss [56]. AP  Ergun  the closeness  2  r  another  equation  k i n e t i c and viscous energy  y  V. (4)  2.  (equation 5), incorl o s s e s , thus  allowing  25  the c a l c u l a t i o n o f p r e s s u r e drop inertia!  flow across packed  AP gc (1 = 1 5 0 L a  Other  Leva  e)  beds. v V  2  relations  beds have been found data.  -  f o r both v i s c o u s and  s  + 1 .75 (1 -  f o r p r e s s u r e drop  by e m p i r i c a l l y  and Grummer [ 5 7 , 5 8 ]  e)  , *  2  (5)  through  correlating  packed  experimental  obtained  0.0243 G D  (6)  for high Reynolds  number f l o w t h r o u g h  Brownell  [59] correlated  and Katz  large particles.  experimental  v e r y f i n e p a r t i c l e s by u s i n g a s t a n d a r d factor,  f , versus Reynolds  Re m u l t i p l i e d sphericity  i s d e p e n d e n t upon t h e p a r t i c l e  porosity.  For laminar flow through the Darcy's drop  equation  type of f r i c t i o n  number, Re, p l o t b u t w i t h f and  by a f a c t o r which  and bed  results for  c o n s o l i d a t e d porous  ( e q u a t i o n 7 ) may b e u s e d  a c r o s s the media [60,61].  media,  f o r pressure  The q u a n t i t y 1/a i s  AP L referred of  cm . 2  to as the p e r m e a b i l i t y c o e f f i c i e n t  (7)  having  a  unit  26 2.2.2  Parameters  of Packed  Bed  T h e c o r r e l a t i o n d i s c u s s e d s o f a r may to f l o w t h r o u g h p a c k i n g s of a r b i t r a r y shapes,  be a p p l i e d provided  individual  p a c k i n g and bed p a r a m e t e r s  parameters  i n c l u d e the p o r o s i t y , p a r t i c l e diameter,  or shape  are a v a i l a b l e .  o f p a r t i c l e s , p a r t i c l e o r i e n t a t i o n and  These sphericity  surface  roughness. Pressure drop in packed  beds  is highly sensitive  to p o r o s i t y as w e l l as to p a r t i c l e o r i e n t a t i o n .  Martin,  McCabe and Monrad [62] i n v e s t i g a t e d the p r e s s u r e drop beds of s p h e r e s w i t h water  f l o w i n g through them.  that f o r a tetragonal arrangement  across  They  found  of spheres with a p o r o s i t y  of 0.3019, the o b s e r v e d p r e s s u r e drop f o r t u r b u l e n t f l o w was  m o r e t h a n 20 t i m e s a s h i g h a s f o r a b e d c o m p o s e d  t h e same s p h e r e s i n c u b i c a r r a n g e m e n t 0.4764.  of  with a p o r o s i t y of  H o w e v e r , s u c h v a r i a t i o n s i n o r i e n t a t i o n do n o t  occur  i n random p a c k i n g ; and t h i s example  o n l y s e r v e s to  indicate  t h e maximum e f f e c t o f o r i e n t a t i o n .  If this voidage  range  were e n c o u n t e r e d i n c r e a s e would  i n a randomly  have  o n l y been  packed  bed t h e  about f i v e fold  pressure-drop [63].  F o r a s p e c i f i c p a c k i n g , s i z e and c o n t a i n e r , t h e bed p o r o s i t y depends  upon the method o f p a c k i n g .  the r e s u l t i n g bed w i l l more s l o w l y . beds w i l l  be d e n s e r  i f the p a r t i c l e s are  Also, with smooth-surfaced  form.  The  l o o s e s t arrangement  by p a c k i n g t h e p a r t i c l e  Generally,  particles,  added denser  are u s u a l l y formed  into a vessel f i l l e d with  water.  27  However, v i b r a t i o n gas  o fvessel  flow through i t will  and  the  effect o fliquid o r  ultimately  compact the  bed.  P a r t i c l e s h a p e i s a much more i m p o r t a n t in porosity variables  than is surface act  sphericity,  i n the  the  sized  r o u g h n e s s , though both o f the  s a m e way.  The  more open i s the  dependence o fporosity  1.0  lower the  bed.  Figure  upon s p h e r i c i t y  granular particles  variable  and  the  particle 6 shows  the  f o r beds o f u n i f o r m l y  packing method  [64]  —i '5  0.8  oose eking  b\  >\ \ 1  De'nse, pac.king  0  0.2  0.4  rJorma 1  OA fT~  p  ackin g  0.6  0.8  1.0  Porosity  Figure  6. S p h e r i c i t y a s a f u n c t i o n o f p o r o s i t y f o r r a n d o m packed beds o f u n i f o r m - s i z e d p a r t i c l e s [66].  The i n a bed  p r e s e n c e o f f i n e and  o flower porosity  u n i f o r m p a r t i c l e s , f o r the between the  larger  ones.  of p a r t i c l e s i z e s , the  coarse particles  than would be o b t a i n e d fine particles In general,  lower i s the  the  results with  f i l l the  spaces  w i d e r the  range  porosity  obtained.  28 2.2.3  Blocking  of Pores  in Porous  In f i l t r a t i o n , penetrates  Media  some f i l t e r : ; c a k e s o l i d  t h e f i l t e r medium and  fills  usually  some o f t h e  pores.  As a r e s u l t , t h e p o r o s i t y o f t h e m e d i u m i s d e c r e a s e d r e s i s t a n c e to flow  through  the medium i n c r e a s e s  Suspended matter factor in reducing [65,66,67].  was  of the suspended p a r t i c l e s , the s o i l  smaller  pores.  Artificial  is widely  used  s h a f t s , subways and installation  one  in soil other  period, alone  al.  i n one  of  to a lower  the  engineering  porosity.  freeze-  i n the b u i l d i n g  u n d e r g r o u n d s t r u c t u r e s , and pits for hydraulic widely  i n the S o v i e t Union has  al.  [70].  the  where  been f r o z e n  by K h a k i m o r [ 6 8 ] , S a n g e r H a s h e m i et  in  of  structures.  of the f r o z e n ground c o n s t r u c t i o n  [ 6 9 ] , and  pores,  Soil  i n the b u i l d i n g of a subway  have been p r e s e n t e d et  penetrate  f r e e z i n g o f g r o u n d by m e a n s o f  been used  Excellent reviews  Takashi  due  m i l l i o n cubic meters of soil  ten year  niques  of  of foundation  T h i s method has over  is increased  Freezing  Artificial pipes  diameter  t h e s u s p e n d e d p a r t i c l e s f i l l up t h e  the r e s i s t a n c e to flow  2.3  soil  the  some p a r t i c l e s may  but e v e n t u a l l y d e p o s i t e d As  dominant  through  s i z e i s l a r g e r than  the  sharply.  t o be t h e  the r a t e of water f l o w i n g  When t h e p o r e  through  found  and  in a  [68]. tech[6],  29 In t h i s m e t h o d , rows o f v e r t i c a l usually four to s i x inches i n diameter four f e e t apart around  freezing pipes,  [6] are placed  about  t h e c o n s t r u c t i o n area and c h i l l e d  brine o f -20°C [68] i s c i r c u l a t e d t o e x t r a c t heat from the ground. the  The f r e e z i n g o f t h e water  i n the pores  stabilizes  soil. Artificial  freezing of soil  usually a last resort expedient.  i s expensive  Experience  and i s  i s limited to  a f e w c o n t r a c t i n g c o m p a n i e s who h a v e m u c h u n p u b l i s h e d information. properties technique  Most r e p o r t s omit  [ 6 8 ] . Another i n many c a s e s  refrigerant circulation  vital  disadvantage  data, such as  t h a w s when t h e  This allows full  p r e s s u r e t o r e t u r n on t h e f o r m a t i o n .  soil  with the f r e e z i n g  i s that the soil stops.  valuable  formation  Chapter 3 CONSOLIDATION OF POROUS FORMATION USING GAS HYDRATE  3.1  Previous  Studies  Pinder, in his patent [4], proposed consolidating water-bearing  e a r t h and  porous  a process for formations  d u r i n g c o n s t r u c t i o n and e x c a v a t i o n by i n j e c t i n g gas o r hydrate former at  i n t o the water  predetermined  c o n t a i n e d i n the  l o c a t i o n s . The  in the pores of the s o i l w i l l block water of  flow.  solid  hydrate which  forms and  By s e l e c t i n g a h y d r a t e f o r m e r o r a m i x t u r e  than t h a t of the f o r m a t i o n temperature, f a i r l y easily without  the expensive  high pressure of underground  stabilize  formation  c o n s o l i d a t e the f o r m a t i o n  hydrate formers with a d i s s o c i a t i o n  The  liquid  the h y d r a t e Evrenos,  temperature  higher  a hydrate will  refrigeration  form  cost.  soil formation will  help  formed.  Heathman and  t h a t p r o p a n e g a s h y d r a t e may  Ralstin  be f o r m e d  [5] e s t a b l i s h e d in porous  rocks  and  the f o r m a t i o n o f such a gas h y d r a t e r e d u c e s o r e l i m i n a t e s rock p e r m e a b i l i t y .  They proposed  p r o p e r l y l o c a t e d r e g i o n may from  underground  t h a t hydrates formed  be u s e d  gas r e s e r v o i r s . 30  to seal o f f  leakage  in a  31  Noble [71] has also demonstrated that  Freon-11  hydrate reduces t h e p o r o s i t y o f sand f o r m a t i o n f a i r l y tively  3.2  i n a small  bench s c a l e a p p a r a t u s .  Purpose o fthis  Study  In t h i s s t u d y o f t h e c o n s o l i d a t i o n formation, gas hydrate will  be formed  to d e t e r m i n e i t s e f f e c t i v e n e s s conditions. several  effec-  o f porous  i n t h e pores o f sand  under d i f f e r e n t  B e f o r e t h i s t e c h n i q u e c a n be a p p l i e d  operating i n practice,  q u e s t i o n s must be answered: (a)  What d e g r e e o f s u b c o o l i n g i s n e c e s s a r y f o r a g a s h y d r a t e t o be f o r m e d in a sand f o r m a t i o n and e f f e c t i v e l y reduce i t s permeabiI ity? The d e g r e e o f s u b cool ing w i l l determine the choice of hydrate former or mixture of hydrate f o r m e r s t o be u s e d in particular situations.  (b)  After the hydrate i s formed in the formation, is i t probable that i t might melt o r break easily?  (c)  What i s t h e e f f e c t o f p a r t i c l e o r sand sizes i n the formation of gas hydrate?  (d)  How m u c h t i m e i s n e e d e d f o r c r y s t a l growth? A reasonable length of time i s r e q u i r e d t o pump t h e h y d r a t e former i n t o t h e sand f o r m a t i o n and t o a l low the hydrate former t o d i f f u s e to a larger area in the formation. If the formation is blocked too rapidly, a l a r g e number o f i n j e c t i o n p o i n t s w i l l be needed.  (e)  How m u c h h y d r a t e f o r m e r i s required t o e f f e c t i v e l y e l i m i n a t e p e r m e a b i I. i t y ? What c o n c e n t r a t i o n o f h y d r a t e former s h o u l d be u s e d ?  32  Chapter 4  EXPERIMENTAL APPROACH  4.1  Choice  of Hydrate Choosing  dation  Former  a hydrating  of a porous formation  a g e n t f o r use  is a difficult  in the  consoli-  problem  since  i t d e p e n d s on a r a t h e r l a r g e n u m b e r o f p r o p e r t i e s o f a g e n t and  i t s hydrate.  For the agent, these  the  properties  include i t s cost, f1ammabi1ity, s o l u b i l i t y in water, (if i t is a liquid), toxicity, and  vapour pressure  important tion,  f a c t o r s are  composition,  permeability, Unfortunately, the  (boiling  hydrates,  and  the  most other  properties  as a b a s i c s t u d y was  beyond the  hydrate  heat  For the  hydrate,  pressure  of formation,  strength  from the  of the  formashape,  crystal.  thermodynamic properties  former for this  of the p h y s i c a l  properties  scope of t h i s work. design  Since and  of  unknown. study  that are a v a i l a b l e from the  former d i c t a t e s the  the  of  size,  p r o p e r t i e s are mostly  Selecting a hydrate b a s e d on  point).  mechanical  apart  c o r r o s i v i.ty , r f a t e - b f h y d r o 1 y s i s  t e m p e r a t u r e and  density,  density  was  literature,  of the  the choice  construction  hydrate of of  33  equipment  required, a hydrate former  the e a r l y stages of the  h a d t o be c h o s e n  study.  The main f a c t o r s a f f e c t i n g t h e c h o i c e o f former were the ease of h a n d l i n g of the agent, critical  temperature  hydrate  toxicity,  and p r e s s u r e o f f o r m a t i o n , c o s t  a v a i l a b i l i t y of the agent  and equipments  required,  the o t h e r p r o p e r t i e s were not c o n s i d e r e d because e i t h e r u n a v a i l a b l e or considered unimportant. s u c h as t h e s i z e , shape  growth  and Some o f  they  crystals,  are very scarce.  On  o t h e r h a n d , . p r o p e r t i e s s u c h as t h e h e a t o f f o r m a t i o n c o n s i d e r e d not very important  d i f f u s i o n c o n t r o l l e d (see s e c t i o n ( C C 1 F ) was  nor c o r r o s i v e .  Freon-11  haveaa  most i m p o r t a n t former  fairly  under  8.28°C.  pressure.  handled  although  However,  as t h e  the  hydrate Freon-11  pressure at a temperature  hydrate c r i t i c a l  t u r e i s a l s o 8.28°C and psia.  room t e m p e r a t u r e  c o n d i t i o n s of formation.  a hydrate at atmospheric The  23.8°C  It is easily  3  reason that i t i s chosen  is its critical  former  flammable  b o i l i n g point of  high vapour  forms  i s 12.2  as t h e h y d r a t e  gm/cm .  s i n c e i t i s a l i q u i d a t normal i t does  basically  i s not t o x i c , not  I t has a normal  a n d a l i q u i d d e n s i t y o f 1.46  were  2.1.7).  chosen  3  several reasons.  the  s i n c e p r e v i o u s s t u d i e s on  h y d r a t e f o r m a t i o n had shown t h a t t h e k i n e t i c s a r e  for  are  Properties  and p e r m e a b i l i t y o f the  and the k i n e t i c s o f c r y s t a l  Freon-11  in  decomposition  its critical  F u r t h e r , i t s phase  decomposition  diagram  of  temperapressure  ( F i g u r e 7)  and  70 50  Liquid  03  Freon - n  40  a  .  30  Solid  Hydrate +  Liquid  Water  LU  tr  Liquid  Water  20  if)  LU a.  F r e o n - n Vapour +  10 9 8 7 6  Liquid  0  10 T E M P E R  15 ATU  Water  20  25  30  R E,  F i g u r e 7. P h a s e d i a g r a m o f F r e o n - 1 1 - w a t e r system with water present i n excess [17].  35  35  i t s e q u i l i b r i u m data a r e a v a i l a b l e and have been s t u d i e d v e r y t h o r o u g h l y by v a r i o u s i n v e s t i g a t o r s o f gas [15,31,32]. mation  In a d d i t i o n , a l i m i t e d amount o f k i n e t i c  infor-  i s a l s o a v a i l a b l e [ 5 2 ] . Table V summarizes the  physical  4.2  hydrates  and chemical  Choice of The  p r o p e r t i e s of, F r e o n - 1 1  POKOUS  and i t s h y d r a t e .  Formation  c h o i c e of a porous  f o r m a t i o n t o be u s e d i n  t h i s s t u d y was q u i t e a r b i t r a r y .  I t was d e c i d e d t h a t a t s u c h  an e a r l y s t a g e o f e x p e r i m e n t a t i o n , i t i s n o t n e c e s s a r y t o use an a c t u a l c o r e s a m p l e . n a r r o w r a n g e §f  diameters  Instead, uniform particles of a may g i v e a b e t t e r  understanding  of the process of hydrate formation i n the pores of a tion.  A s a r e s u l t , 2 0 - 6 0 m e s h s a n d was c h o s e n  in t h i s work.  The sand p a r t i c l e s were a g a i n  separated into four size ranges,  forma-  as t h e medium arbitarjly  namely, 24-32 mesh,  32-42  as gas h y d r a t e and sand  as  mesh, 42-48 mesh and 48-60 mesh.  4.3  Plan f o r Experimental With  the porous  Freon-11  Study  chosen  f o r m a t i o n , a s t r a t e g y h a d t o be d e v i s e d  any e x p e r i m e n t a l  before  w o r k c o u l d be b e g u n i n o r d e r t o a n s w e r  those questions presented  i n S e c t i o n 3.2.  In g a s h y d r a t e f o r m a t i o n , a g i t a t i o n i s a v e r y important v a r i a b l e ( S e c t i o n 2.1.7).  However, i n forming  36  Table V P r o p e r t i e s o f Freon-11  CC1 F  Formula  3  Molecular Cost  Weight  137.36  (per 5 gallon)  Normal  andIts Hydrate  Boiling  $47.15  Point  23.8°C  [32]  L i q u i d D e n s i t y a t Normal Boiling Point  1.46  Critical  1.98°C  [72]  6 35 p s i a  [72]  Practically Insoluble  [72]  92  [32]  Critical  Temperature Pressure  Solubility Molecular  in  Water  Volume  gm/cc  [15]  c.c.  Odor  Faint ethereal  [72]  Flammabi1ity  Non-Flammabie  [72]  Toxi ci ty  Less Toxic than C 0  Hydrate  Composition  16.6  moles  Hydrate Crystal Structure  T y p e 11  Calculated Crystal  1.15  Density  Hydrate C r i t i c a l Temperature  Decomposition  Hydrate C r i t i c a l Pressure  Decomposition  Heat o f R e a c t i o n W(sS'vg}"?f n H a & ' C Mv?:hH' 0,c :  ;  2  2  H 0/moles F - l l 2  gm/c.c  [32]  [15]  8.28°C 12.7  [72]  [31] ps ia  3 5 . 4 4 7 ;kc;al/gm  [31] mole  [32]  37  hydrate tion  i n a sand  is quite impossible.  and w a t e r 11  formation, a g i t a t i o n o f the whole Using  would solve this problem.  i n water  Small  o f Freon-11 droplets of Freon-  would provide a large surface area f o r hydrate  f o r m a t i o n and t h e sand  p a r t i c l e s would provide the nuclea-  tion sites f o r initiation  of hydrate  Once t h e e m u l s i o n duced  an e m u l s i o n  forma-  i n the sand  o f Freon-11 and water  formation, the temperature  w o u l d g i v e n an i n d i c a t i o n was o c c u r r i n g o r n o t . formation will  formation.  of the formation  of whether the hydrate  formation  The heat e v o l v e d d u r i n g t h e h y d r a t e  h e a t up t h e s a n d  in order f o r hydrate  is intro-  formation  b e d a n d has t o be r e m o v e d to continue.  To m e a s u r e t h e c h a n g e o f p e r m e a b i l i t y o r p o r o s i t y of  the formation  drop  as t h e h y d r a t e  t h e sand  some u p p e r blockage  pressure  I f p e r m e a b i l i t y has  formation, the pressure  any flow a c r o s s the bed w i l l Physical  of  the hydraulic  a c r o s s t h e b e d o f s a n d was u s e d .  been e l i m i n a t e d from for  formed,  theoretically  be  drop  infinite.  l i m i t a t i o n s on t h e e q u i p m e n t r e q u i r e d t h a t  p r e s s u r e drop  i n these tests?  be c h o s e n  as an i n d i c a t i o n o f  I t was f e i h t t h a t a p r e s s u r e  1000 p s i a a c r o s s a b e d o f t w o i n c h e s o f s a n d  high enough t o r e p r e s e n t the complete  should  blockageodf,al1  drop be the pores  in the formation. The to  complete  additional  v a r i a b l e s which  h a d t o be c o n s i d e r e d  t h e o b j e c t i v e s o o f tifch.i sH'Workwwere?.as f o l l o w s :  38  4.4  (a)  Hydraulic of sand  pressure  (b)  Temperature  (c)  Porosity particle  (d)  Crystal  (e)  Amount and c o n c e n t r a t i o n emu Is i o n needed.  of  the  of sand size, growth  drop  across  sand  bed  formation,  formation,  period,  a  i.e.  and of  Freon-11  Equipment A schematic diagram o f t h eequipment used i s given  i n F i g u r e 8; a n d a p h o t o g r a p h all  showing t h earrangement o f  t h eequipment used i s given  i n F i g u r e 9.  The s p e c i f i c a t i o n s  Q f o f i h e f v a n i o u s r p i e c e s o f e q u i p m e n t g a r e ^ g i v e n : j i m ^ A p p e n d i x B. The s a n d b e d was p l a c e d pressure  cell,  i n t h e centre o f a high  t h es t r u c t u r e and dimensionsoof*which a r e found  i n F i g u r e 1 0 . F i g u r e 11 i s a p h o t o g r a p h of t h e c e l l . steel six  The cell  tube with  inches.  o f a l l the parts  basically consisted of a stainless  i n s i d e diameter o f one inch and length o f  A t w o - i n c h b e d o f s a n d was h e l d i n t h e c e n t r e ,  s u p p o r t e d by two p i e c e s o f s i n t e r e d s t a i n l e s s s t e e l p l a t e ( t h i c k n e s s = 0.075 i n c h ) , w h i c h were s u p p o r t e d by two s t a i n less steel plates d r i l l e d with  0.1 i n c h h o l e s .  The bed  was h e l d i n p l a c e b y a s t a i n l e s s c y l i n d e r p l a c e d a t e a c h end o f t h e b e d . An i r o n - c o n s t a n t a n  t h e r m o c o u p l e was p l a c e d  i n t h e s a n d b e d a t a d i s t a n c e o f 2.4 i n c h e s of thec e l l .  Two p r e s s u r e  tubes  (1.5 inches  from t h e i n l e t from each end  HX-  High Pressure Pump  -XJ-  Rotameter  R >  Pressure Transducer  tt  Cold  Tap Water  iStirrer  4)  Manometer  Pressure Cell  ft  f  Drain  Graduated Cylinder  t  Sample M^XING° TANK  N  F i g u r e 8.  Centrifugal ump  TEMPERATURE  p  Flow diagram of equipment  oo  U3  for consolidation  study.  Figure 9.  Arrangement of Equipments f o r c o n s o l i d a t i o n  study.  Note:  F i g u r e 10.  a l l dimensions are in  S t r u c t u r e of high pressure  cell.  inches  F i g u r e 11.  Parts of high pressure  cell.  43  of  t h e c e l l ) were used  t o measure the p r e s s u r e drop  across  the bed. The  high pressure cell  constant temperature  bath with  water and ethylene glycol  was i m m e r s e d i n a F o r m a  10 g a l l o n s o f m i x t u r e o f  (Figure 12).  I t s h o u l d be n o t e d  that a l l the pressure tubes  a r e above t h e mixture  constant  This ensured  temperature  bath.  tubes were n o t c l o g g e d in  in the  that the pressure  up b y t h e f o r m a t i o n o f g a s h y d r a t e  them. C o l d w a t e r pumped t h r o u g h  by a h i g h p r e s s u r e pump was u s e d  a rotameter  and c e l l  to purge the system  and t o  o b t a i n p r e s s u r e drop measurements f o r p o r o s i t y c a l c u l a t i o n s . The  h i g h p r e s s u r e pump was u s e d  pressure  the hydraulic  (maximum o f 1 0 0 0 p s i a ) t h a t was u s e d  s t r e n g t h o f sand gas  to produce  formation  to test the  after c o n s o l i d a t i o n with the  hydrate. The  p r e s s u r e drop  through  t h e b e d was m e a s u r e d  by a m e r c u r y m a n o m e t e r a t l o w p r e s s u r e d i f f e r e n c e a n d b y a BLH  high l i n e ,  high d i f f e r e n t i a l  high pressure d i f f e r e n c e . nected  transducer at  A p r e s s u r e g a u g e was a l s o  con-  t o t h e o u t l e t o f t h e h i g h p r e s s u r e pump t o e n s u r e  that the pressure d i d not exceed 1000  pressure  the designed  limit of  p s i g f o r t h e pump. The  emulsion  o f F r e o n - 1 1 a n d w a t e r w h i c h was t h e  i n j e c t i o n medium f o r t h e h y d r a t e  former  was m i x e d i n a  5 - g a l l o n p o l y e t h l e n e ^ t a h k . A A g i t a t i o n •A?wa.s '*pro vi d e d b y t w o ,  :  F i g u r e 12.  High p r e s s u r e c e l l shown immersed i n t h e constant temperature bath.  45 v a r i a b l e speed s t i r r e r s . to the coil the  Two c e n t r i f u g a l  pumps w e r e  c i r c u l a t e the emulsion and to pass the emulsion pressure cell.  C o l d t a p water, c i r c u l a t i n g  used  through  through a  o f c o p p e r t u b i n g i n t h e m i x i n g t a n k was u s e d t o c o o l emulsion. The t e m p e r a t u r e o f t h e c o n s t a n t t e m p e r a t u r e  of  the emulsion and o f the p r e s s u r e c e l l  iron-constantan thermocouples. these thermocouples  bath,  w e r e m e a s u r e d by  The c a l i b r a t i o n c u r v e o f  i s g i v e n i n A p p e n d i x C.  T h e e m u l s i o n i n t h e m i x i n g t a n k was c o o l e d t o a temperature o f a p p r o x i m a t e l y 9-10°C.  The degree o f c o o l i n g  was c o n t r o l l e d m a n u a l l y by a d j u s t i n g  the f l o w r a t e of cold  tap  T h e e m u l s i o n was m a i n -  water through the cooling c o i l .  tained at this temperature f o r several  reasons.  A tempera-  t u r e l o w e r t h a n 5 - 6 ° C may c a u s e h y d r a t e t o b e f o r m e d i n t h e mixing tank.  A t t e m p e r a t u r e much h i g h e r t h a n 1 0 ° C , a c o n -  s i d e r a b l e amount o f Ereon-11 would v a p o r i z e c a u s i n g a change in c o n c e n t r a t i o n . The  volume o f t h e Forma c o n s t a n t t e m p e r a t u r e  is a b o u t l O gallon.  I t c a n be c o n s i d e r e d a s a n  heat sink f o r the pressure c e l l .  infinite  Good m i x i n g o f t h e f l u i d  i n t h e b a t h was p r o v i d e d b y c i r c u l a t i o n o f t h e f l u i d centrifugal  pump.  bath  by a  T h e t e m p e r a t u r e o f t h e b a t h d e v i a t e d no  more than .1°C from t h e s e t - p o i n t v a l u e .  46  4.5  Procedure  4.5.1  The Main  Procedure  f o r Sand C o n s o l i d a t i o n  After the pressure cell  was p a c k e d w i t h s a n d o f  t h e d e s i r e d s i z e a n d was p l a c e d i n t h e c o n s t a n t b a t h , w a t e r was p a s s e d t h r o u g h t h e c e l l air  trapped inside the cell  the c e l l at  started until at  a n d w a t e r was m i x e d of  about  The  cold water  a t the bath temperature f o r  Meanwhile,  an e m u l s i o n o f  i n the mixing tank.  T h i s sample  a n d was l e f t  s e p a r a t e d from the water.  temperature  a n d a r u n was n o t  Freon-11  An e m u l s i o n  2 5 0 ml was t a k e n t h r o u g h t h e s a m p l i n g  inlet of the c e l l . of  devices.  was m o n i t o r e d  i t had remained  l e a s t h a l f an h o u r .  t o remove a l l t h e  and i n the t u b i n g c o n n e c t i n g  to the pressure measuring  the centre of the cell  temperature  sample  tube a t the  was t h e n p l a c e d i n a t a n k  there until  the Freon-11  had  A c o n t r o l l e d amount o f e m u l s i o n  was p a s s e d t h r o u g h t h e s a n d b e d i n t h e c e l l .  After the  v a l v e s were a l l c l o s e d , t h e c e l l  was l e f t  a predetermined  Then t h e p e r m e a b i l i t y o f  length of time.  t h e s a n d b e d was m e a s u r e d by m e a s u r i n g drop a c r o s s the bed. build  i n the bath f o r  the hydraulic pressure  T h e h i g h p r e s s u r e pump w a s u s e d t o  up t h e p r e s s u r e o n t h e i n l e t s i d e o f t h e c e l l .  The  maximum p r e s s u r e d r o p a c r o s s t h e b e d o b t a i n e d was m e a s u r e d and  recorded. To p r e p a r e f o r a n o t h e r r u n , t h e c e l l  was  removed  f r o m t h e b a t h a n d was i m m e r s e d i n a b a t h o f h o t w a t e r  47 ( t e m p e r a t u r e o f about 60°C) t o remove t h e Freon-11 i n t h e cell.  Then  the cell  was r e p l a c e d i n t h e c o n s t a n t  bath.  W a t e r was u s e d t o p u r g e  the system  Freon-11 from the p r e v i o u s run remained Then  the experiment  4.5.2  temperature  t o e n s u r e no  in the pressure  cell.  was r e p e a t e d .  C o n t r o l and Measurement o f C o n c e n t r a t i o n I t was d i f f i c u l t  t i o n o f Freon-11 emulsion  to maintain a constant concentrai n t h e mixing tank because  pressure of Freon-11.  high vapour  T h e r e was  of the  a continuous  v a p o r i z a t i o n o f Freon-11 i n t o t h e atmosphere.  T h i s was  r e d u c e d by c o v e r i n g t h e m i x i n g t a n k and t h e s t i r r e r s w i t h a plastic  sheet. Instead of trying to maintain a constant  concen-  t r a t i o n f o r a s e r i e s o f r u n s , r u n s w e r e made a t w h a t e v e r concentration In  had been  r e a c h e d by t h e e m u l s i o n  i n the tank.  t h e b e g i n n i n g o f a s e r i e s o f r u n s , a m i x t u r e o f an  approximate  c o n c e n t r a t i o n was m a d e u p .  Then  a series of  r u n s was made w i t h d e c r e a s i n g c o n c e n t r a t i o n as p a r t o f F r e o n - 1 1 was  lost.  To m e a s u r e t h e c o n c e n t r a t i o n o f F r e o n - 1 1 i n t h e e m u l s i o n , a 2 5 0 ml s a m p l e each r u n . The sample measuring out.  Then  before  was t h e n a l l o w e d t o s e t t l e i n a  cylinder until t h e voJlumee  o f t h e e m u l s i o n was t a k e n  t h e F r e o n - 1 1 was c o m p l e t e l y s e p a r a t e d  o f water and Freon-11 i n t h e sample  48  were determined.  To a v o i d l o s s o f F r e o n - 1 1 from  t h e c y l i n d e r was i m m e r s e d i n c o l d w a t e r w h i l e  the sample,  the Freon-11  separated. Table typical  emulsion  VI g i v e s t h e c o n c e n t r a t i o n obtained  I t shows t h a t t h e e m u l s i o n also proved  of Freon-11 i n a  by f i v e r e p l i c a t e m e a s u r e m e n t s . u s e d was h o m o g e n e o u s , a n d i t  t h a t a s a m p l e o f 2 5 0 ml w i l l  give a  concentration  c l o s e t o t h a t o f a 1 0 0 0 ml s a m p l e  Table  VI  V a r i a t i o n o f Amoiintoof Freon-11 i n F i v e R e p l i c a t e Measurements of Emulsion Concentration Volume o f Emulsion (ml)  Volume o f Freon-11 (ml)  Volume F r a c t i o n of Freon-11  45 98 85 1 38 180  .183 .185 .187 .1 90 .187  245 260 455 725 960  4.5.3  Measurement of P o r o s i t y Among t h e f o u r s a n d  s i z e s used  i n t h i s work, the  sand  p a r t i c l e s o f 48-60 mesh were t o o s m a l l  each  r u n , some o f t h e p a r t i c l e s w e r e w a s h e d o u t o f t h e c e l l .  Thus r e s u l t s o b t a i n e d with dependable.  these  sand  since  during  beds were not very  49  The  initial  p o r o s i t y o f t h e sand bed o f each  was o b t a i n e d b y p r e s s u r e d r o p m e a s u r e m e n t .  The  size  calculation  of p o r o s i t y and D a r c y ' s p e r m e a b i l i t y f a c t o r f o r t h e d i f f e r e n t s a n d beds b e f o r e gas h y d r a t e f o r m a t i o n i s shown i n A p p e n d i x E.  Chapter 5  RESULTS AND DISCUSSIONS  5.1  Hydrate F o r m a t i o n i n Sand O n e o f t h e a i m s o f t h e p r e s e n t w o r k was t o c o n f i r m  t h a t gas h y d r a t e s formed  i n porous formations w i l l  rock p e r m e a b i l i t y . P r e l i m i n a r y work o f t h i s s t u d y  reduce was  involved in exploring various experimental procedures would y i e l d  which  reproducible results.  T h e f a c t t h a t g a s h y d r a t e was f o r m e d  i n the sand  f o r m a t i o n i n t h e h i g h p r e s s u r e c e l l , was s h o w n b y t h e e v o l u tion of heat which  caused a temperature r i s e  i n the sand.  A s t h e e m u l s i o n was p a s s e d t h r o u g h t h e c e l l , t h e t e m p e r a t u r e of the  the centre of the cell emulsion.  A f t e r t h e e m u l s i o n f l o w was s t o p p e d , t h e  temperature of the cell bath.  was r a i s e d t o t h e t e m p e r a t u r e o f  was c o o l e d down b y t h e t e m p e r a t u r e  F i g u r e 13 s h o w s t h e c o o l i n g c u r v e o f t h e c e n t r e o f  the  sand  ( s i z e = 32-42 mesh) a t a bath t e m p e r a t u r e o f 1°C.  The  initial cooling  r a t e o f t h e e m u l s i o n was s i m i l a r t o  that of pure water i n the c e l l conditions the  (Figure 14).  under s i m i l a r o p e r a t i n g  At the temperature of about 2°C,  t e m p e r a t u r e o f the sand bed i n c r e a s e d a g a i n to g i v e a 50  F i g u r e 13.  C o o l i n g c u r v e o f sand bed w i t h gas (bath temperature = 1°C).  hydrate forming in  pores  F i g u r e 14.  C o o l i n g c u r v e o f s a n d bed w i t h o u t gas h y d r a t e forming in pores (bath temperature = 1°C).  £  53  peak o f a p p r o x i m a t e l y 3°C. to bath temperature  Then the temperature  i n a b o u t two  decreased  hours.  The f a c t t h a t t h e t e m p e r a t u r e o f t h e c e n t r e o f t h e c e l l was  never h i g h e r than 3°C, a temperature w e l l  the Fron-11  hydrate decomposition temperature of 8.28°C  t h a t h e a t t r a n s f e r was  not a problem i n t h i s  shows  experiment.  T h u s t h e r e .w.as:- s u f f i c i e n t m i x i n g i n t h e t e m p e r a t u r e w h i c h may  below  bath  be c o n s i d e r e d a s a n i n f i n i t e h e a t s i n k f o r t h i s  e x p e r i ment. The p r o c e s s o f h y d r a t e f o r m a t i o n i s v e r y to c r y s t a l l i z a t i o n  in which  crystals will  similar  not form  until  t h e s o l u t i o n i s s u p e r c o o l e d and i s i n i t i a t e d by some n u c l e a tion process. h y d r a t e was was  T h i s f a c t was  not formed u n t i l  c o o l e d t o 2°C  c o n f i r m e d by t h e f a c t t h a t the sand bed and t h e  ( F i g u r e 1 3 ) w h i c h may  nucleation temperature.  emulsion  be c o n s i d e r e d a s a  However, the i n i t i a t i o n o f the  h y d r a t e f o r m a t i o n d e p e n d e d upon v a r i a b l e s o t h e r t h a n ture alone.  T h e n u c l e a t i o n t e m p e r a t u r e was  d i f f e r e n t c o n d i t i o n s a n d d i f f e r e n t r.unss a case where the n u c l e a t i o n temperature  tempera-:  different  F i g u r e 15 i s about  under  shows  3°C.  The n u c l e a t i o n p r o c e s s i n gas h y d r a t e f o r m a t i o n d i d n o t c a u s e any p r o b l e m  in this study.  should provide s u f f i c i e n t  nucleatiion s i t e s f o r the  tion step.  Although the s i z e of Freon-11  The  sand  particles initia-  globules in the  emul s i o n woul d e a l so i n f 1 u e n e e t t h e n u c l e a t i o n ' o f • t h e h y d r a t e , no d i f f i c u l t i e s w e r e e n c o u n t e r e d a s l o n g a s a h o m o g e n e o u s e m u l s i o n was  used.  55  A f t e r the formation of hydrate in the pores completed, the c o r e of sand i n the p r e s s u r e c e l l taken out of the c e l l the  for examination.  I t was  was  c o u l d be  found  that  s a n d f o r m a t i o n had become a b l o c k as s o l i d as r o c k .  F i g u r e 16 i s a p h o t o g r a p h  of the core of sand.  No  attempt  has b e e n made t o m e a s u r e t h e c o m p r e s s i v e s t r e n g t h o f t h e core. F i g u r e 17 i s an e n l a r g e m e n t It shows the gas h y d r a t e c r y s t a l the  5.2  sand  of the core of  formed  in the pores  sand. of  bed.  E f f e c t of Bath  Temperature  A t t e m p t s w e r e made t o f o r m t h e gas h y d r a t e i n t h e s a n d bed a t v a r i o u s t e m p e r a t u r e s between 1°C and 4 ° C . was  found that hydrate forms  bath temperature of 1 to 2°C.  readily  It  i n t h e sand bed a t a  O n c e t h e h y d r a t e was  e v e n w h e n . t h e h y d r a u l i c p r e s s u r e on o n e  formed,  s i d e o f the bed  was  F i g u r e 16.  C o r e o f s a n d b l o c k e d by g a s hydrate formed i n pores.  F i g u r e 17.  Gas h y d r a t e c r y s t a l s f o r m e d pores of sand bed.  in  57  b u i l t up t o a b o v e 1 0 0 0  p s i a , t h e r e was  no v i s i b l e f l o w o f  water a c r o s s the bed, showing t h a t a l l the pores i n the sand bed were c o m p l e t e l y b l o c k e d .  For a higher bath  t u r e , t h e b l o c k a g e o f t h e p o r e s was t h e r e was  not so c o m p l e t e  a small seepage of flow a c r o s s the  temperaand  bed.  F i g u r e 18 s h o w s t h e r e l a t i o n s h i p b e t w e e n  bath  t e m p e r a t u r e and t h e b l o c k a g e o f t h e p o r e s o f t h e s a n d t i o n which  forma-  i s e x p r e s s e d i n terms of p r e s s u r e drop a c r o s s  the bed.  A s t h e t e m p e r a t u r e was  i n c r e a s e d f r o m 1° t o  t h e r e was  no v i s i b l e e f f e c t on t h e b l o c k a g e o f t h e p o r e s .  H o w e v e r , a s t h e t e m p e r a t u r e was some h y d r a t e had f o r m e d in the sand bed. of the Freon-11  i n c r e a s e d to 3i°C,  i n t h e p o r e s , t h e r e was  no  Noting that the d i s s o c i a t i o n  3°C,  although blockage  temperature  h y d r a t e i s 8 . 2 8 ° C , a s u b c o o l i n g o f 5°C  r e q u i r e d to form gas h y d r a t e i n the sand bed and  was  effectively  e l i m i n a t e the p e r m e a b i l i t y of the f o r m a t i o n . F i g u r e 19 i l l u s t r a t e s  the e f f e c t of  i n c r e a s e on t h e s a n d b e d t h a t was hydrate formed  in pores.  b l o c k e d by h y d r a t e f o r m e d t u r e was  temperature  a l r e a d y b l o c k e d by  The 32-42 mesh sand bed at 1°C.  4 0 0 p s i a was  was  Then the bath  increased l i n e a r l y while a pressure of  gas  temperaabout  a p p l i e d a t one s i d e o f t h e s a n d bed.  The  t e m p e r a t u r e o f t h e s a n d bed i n c r e a s e d l i n e a r l y a t t h e same r a t e as t h e b a t h t e m p e r a t u r e .  The t e m p e r a t u r e o f t h e  bed r e m a i n e d  (approximately the  c o n s t a n t at 8.5°C  sand  F i g u r e 18.  E f f e c t o f t e m p e r a t u r e on t h e f o r m a t i o n of gas h y d r a t e i n sand p o r e s .  F i g u r e 19.  E f f e c t o f t e m p e r a t u r e i n c r e a s e on t h e b l o c k a g e o f s a n d bed by g a s h y d r a t e s .  60  dissociation  temperature of Freon-11  hydrate) showing  m e l t i n g o f the gas h y d r a t e at t h a t t e m p e r a t u r e . i n c r e a s e i n t e m p e r a t u r e a b o v e 8 . 5 ° C was passed through the cell  The  the sudden  c a u s e d by t h e  water  a f t e r the gas h y d r a t e m e l t e d .  This  r e s u l t s h o w s t h a t a f t e r a s a n d f o r m a t i o n i s b l o c k e d by gas h y d r a t e formed will the  the  a t low t e m p e r a t u r e , t h e sand f o r m a t i o n  r e m a i n b l o c k e d even a t a h i g h e r t e m p e r a t u r e as l o n g as t e m p e r a t u r e i s below the gas h y d r a t e  dissociation  temperature.  5.3  Crystal  Growth P e r i o d  Pinder [73] r e p o r t e d t h a t the s i z e of hydrate  crystal  b#tit,e[tr'ahydiro<fiuraind ato;dc hiyjdrogeinl i s M ^ ' h i d e c i ncr'eas'es"" wi t h t i m e . The l a r g e r the h y d r a t e c r y s t a l , the more c o m p l e t e b l o c k a g e o f the p o r e s h o u l d be. was  Hence a f t e r the  the emulsion  p a s s e d t h r o u g h t h e c e l l , a p e r i o d o f ^ a few h o u r s  was  w a i t e d b e f o r e t h e p e r m e a b i l i t y o f t h e s a n d b e d was t e s t e d . T h i s l e n g t h o f t i m e was crystal  n e c e s s a r y to a l l o w the gas  to grow i n the p o r e s of the sand In  varying aging times.  the  bed.  r u n s w e r e made w i t h  F i g u r e 20 s h o w s t h e e f f e c t o f t h e  g r o w t h p e r i o d on t h e b l o c k a g e o f t h e p o r e s .  short crystal  hydrate  o r d e r to f i n d the minimum l e n g t h o f time t h a t  i s r e q u i r e d f o r an e f f e c t i v e g r o w t h ,  crystal  1  g r o w t h p e r i o d , t h e r e was  For a  no b l o c k a g e a c r o s s  bed d e s p i t e the f a c t t h a t the i n i t i a t i o n  step of the  12  I ©  ' i-  i  »  1  2  3  1 1 4  CRYSTAL Figure  20.  Effect of length  5  i  _J  6  GROWTH  of c r y s t a l  7  __L  8.  -L-—J  9  PERIOD,  1  1©  11  -J  12  hr  growth period on blockage  of  pores.  62 h y d r a t e f o r m a t i o n had a l r e a d y t a k e n p l a c e .  A period of  a b o u t two h o u r s was r e q u i r e d t o p r o d u c e a g o o d b l o c k a g e o f the  sand f o r m a t i o n .  ture of the cell two h o u r s .  Recall  f r o m F i g u r e 13 t h a t t h e  tempera-  reached the bath temperature also i n about  Based on t h i s r e s u l t ,  t w o h o u r s was t h e t i m e  t h a t i s r e q u i r e d f o r t h e gas h y d r a t e t o grow to a s i z e l a r g e enough to e f f e c t i v e l y block the pores o f the sand formati on.  5 .4  E f f e c t o f Sand S i z e For  each o f t h e beds o f d i f f e r e n t  sand s i z e  (24-32,  3 2 - 4 2 , 4 2 - 4 8 a n d 4 8 - 6 0 m e s h ) , a s e r i e s o f r u n s w e r e made o v e r a t e m p e r a t u r e range from 1°C t o 4°C w i t h a c o n s t a n t emulsion concentration. I t was f o u n d t h a t t h e s a n d s i z e d i d n o t h a v e a s i g n i f i c a n t e f f e c t on t h e d e g r e e o f s u b c o o l i n g t h a t i s required f o r hydrate formation (Figure 21).  F o r beds o f  s a n d o f 32-42 mesh and 42-48 mesh, t h e maximum that s t i l l  temperature  a l l o w e d a b l o c k a g e o f p o r e s was a p p r o x i m a t e l y  3 ° C , w h i l e f o r t h e 24-32 mesh and 48-60 mesh s a n d b e d , t h a t t e m p e r a t u r e was a b o u t 2 ° C .  T h a t i s an e x t r a d e g r e e o f  s u b c o o l i n g was r e q u i r e d f o r t h e s e two s a n d ' s i z e s t o b l o c k the  pores e f f e c t i v e l y .  For the l a r g e sand s i z e s ,  this  e f f e c t may b e c a u s e d b y t h e f a c t t h a t l a r g e r v o i d a g e r e q u i r e s m o r e h y d r a t e t o be f o r m e d  i n the sand f o r m a t i o n .  As f o r  .5  12  Sand  Size  • 24-32  mesh mesh mesh mesh  'cn  CN I  AT  o  •  •  A  32-42  • 42-48 ® 48-60  • J  1 BATH  © L  2  TEMPERATURE, 01 OJ  Figure.21.  E f f e c t o f sand s i z e on blockage o f pores  64 the s m a l l sand s i z e of 48-60 mesh, the p a r t i c l e s were s m a l l and a l o t o f p a r t i c l e s were washed o u t o f the during each run. the sand bed.  5.5  H e n c e s o m e v o i d may  Thus these r e s u l t s  too  cell  have been c r e a t e d i n  are not too  dependable.  E f f e c t of Hydrate Former C o n c e n t r a t i o n Under ideal  c o n d i t i o n s , the hydrate  o f t h e F r e o n - 1 1 h y d r a t e i s 16.6 Freon-11.  The  moles of H 0 2  composition to 1 mole of  e q u i v a l e n t Freon-11 volume f r a c t i o n  emulsion, t h a t w i l l y i e l d a hydrate of the ideal i s 0.239 ( s e e A p p e n d i x D).  i n an composition,  However, hydrate of c o m p o s i t i o n  l o w e r t h a n t h i s c o u l d be f o r m e d w i t h s o m e v o i d s i n t h e crystal  lattice. In t h i s s t u d y , i t was  emulsion  c o n c e n t r a t i o n was  found t h a t such a high  unnecessary  to form enough  t o b l o c k up t h e p o r e s o f t h e s a n d b e d .  I t was  also  hydrate un-  d e s i r a b l e t o u s e s u c h a h i g h c o n c e n t r a t i o n s i n c e i t was f o u n d much h a r d e r t o o b t a i n a h o m o g e n e o u s e m u l s i o n w i t h a Freon-11 volume f r a c t i o n  g r e a t e r than  0.20.  F i g u r e 22 s h o w s t h e e f f e c t o f c o n c e n t r a t i o n o f e m u l s i o n on t h e b l o c k a g e o f p o r e s a t v a r i o u s I t was  temperatures.  found t h a t the d i f f e r e n c e i n c o n c e n t r a t i o n d i d not  h a v e t o o much e f f e c t on t h e b a t h t e m p e r a t u r e  ( i . e . the  degree of s u b c o o l i n g ) r e q u i r e d to achieve a complete of the pores.  For both volume f r a c t i o n s  o f .13 a n d  blockage .29,  OS  12 Sand  a  3 2 - 4 2 mesh  Freon-ii Volume Fraction a -08  0^  CN I  Size  o  A-13  o -29  8  CL  CC X  a.  CA  1 BATH  2  JL  3  5  A  TEMPERATURE,  C  cn  F i g u r e 22.  E f f e c t o f c o n c e n t r a t i o n o f Freon-11 i n emulsion on t e m p e r a t u r e r e q u i r e d f o r h y d r a t e f o r m a t i o n and b l o c k a g e o f p o r e s .  66 the temperature above  3°C.  at which  unstable bloackage occurred,  However, f o r a low volume f r a c t i o n o f about  t h e r e s e e m e d t o be a n u n s t a b l e t e m p e r a t u r e The  mesh s a n d bed)  a n d i n F i g u r e 24  5.6  E f f e c t of Volume of Emulsion last parameter  volume of emulsion agent  needed  were p l o t t e d  reason f o r  I t was a complete  in the  o r the amount of h y d r a t e  the  the  forming  a series of  o f 1°C w i t h d i f f e r e n t The  runs volume  results  25.  found t h a t the volume r e q u i r e d to a c q u i r e  b l o c k a g e o f the sand bed d e c r e a s e d w i t h  c o n c e n t r a t i o n of the emulsion.  F o r low Freon-11  the  From F i g u r e 25, t h e minimum  v o l u m e f o r e a c h c o n c e n t r a t i o n was on F i g u r e 26.  crystal  formation.  through the pressure c e l l .  in Figure  effec-  i n v e s t i g a t e d was  r e q u i r e d to c o m p l e t e l y b l o c k the sand  of emulsion passed  bed).  Used  t h a t was  made a t a b a t h t e m p e r a t u r e  the  stress.  For d i f f e r e n t c o n c e n t r a t i o n s of Freon-11, was  The  cause a c o l l a p s e of  l a t t i c e when p l a c e d u n d e r  The  on  i s r e q u i r e d to  i s t h a t i f t h e r e a r e t o o many empty c a g e s  crystal  2°C.  ( f o r 42-48 mesh sand  i s a minimum c o n c e n t r a t i o n which  l a t t i c e of the hydrate i t w i l l  .08,  i n F i g u r e 2 3 ( f o r 32-42  t i v e l y b l o c k the pores of the sand bed. this  at about  e f f e c t of c o n c e n t r a t i o n of Freon-11  blockage of pores i s i l l u s t r a t e d  There  was  e s t i m a t e d a n d was  plotted  v o l u m e f r a c t i o n s o f 0.08  to  12 CO a I  X  oo  o  CN  OAOOO  A  A^  8h  A  A  -LU 4 X K <  3  5 CO (f)  *»  yj  ^  Temperature o 1°C A 2°C  0=, FREON-11  VOLUME  FRACTION  F i g u r e 23> E f f e c t o f c o n c e n t r a t i o n o f F r e o n - 1 1 i n e m u l s i o n o n b l o c k a g e o f p o r e s o f sand bed o f s i z e 32-42 mesh.  cn  12 •  P3 CO MM  D.  CN  Temperature 1-5°C A 2-0°C  o  O  AA  O  000  A  I  o X  m  UJ 2 •15 FREON-11 F i g u r e 24.  VOLUME  FRACTION  E f f e c t o fc o n c e n t r a t i o n o f Freon-11 i n emulsion on the blockage of p o r e s o f sand bed o f s i z e 42-48 mesh.  CTl CO  12 cu  '55  o  r r  O  o  6  Freon-ii Volume Fraction 08 o 10 A 12 a 14 @ 16 A 23 • 30  v  7  •3 VOLUME F i g u r e 25.  OF  Amount o f emulsion  EMULSION  • 0  litre  r e q u i r e d t o block the sand  formation  FREON-11 Figure  26.  VOLUME  E f f e c t of Freon-11 concentration  FRACTION  on amount o f e m u l s i o n  required  71  0.15, to  the minimum volume r e q u i r e d d e c r e a s e d f a i r l y  about  200 m l ; t h e n t h e c u r v e l e v e l l e d  with i n c r e a s i n g concentration. because  t h a t was  the t u b i n g .  o f f at about  50  I t l e v e l l e d o f f t o 50  ml  the volume of v o i d spaces  That volume of water  Amount o f Freon-11  Volume F r a c t i o n of Freon-11  bed.  Emulsion  by t h e f i l t e r i n g  was  55 60 50 35 22 25 16  passed through  r e t a i n e d by t h e s a n d  a c t i o n of the bed.  the sand  emulsion are r e q u i r e d to b l o c k the sand  used at each c o n c e n t r a t i o n .  bed,  formation,  This explains  lower c o n c e n t r a t i o n s o f e m u l s i o n , l a r g e r volumes  Table VII summarizes  Bed  Volume of Freon-11 Used (ml)  690 600 450 250 150 110 55  some o f t h e F r e o n - 1 1  and  VII  Minimum Volume of Required (ml)  A s t h e e m u l s i o n was  for  i n the sand  R e q u i r e d to B l o c k the Sand  .080 .10 .11 .14 .16 .23 .30  i.e.  i n the c e l l  ml  h a d t o be r e p l a c e d i n  o r d e r t h a t t h e h y d r a t e c o u l d be f o r m e d  Table  linearly  why  of  formation.  the amount of Freon-11  actually  For lower c o n c e n t r a t i o n s of  72  Freon-11, cases  the a c t u a l amount used  of higher c o n c e n t r a t i o n .  was  passed  was  i n c r e a s e d t o a b o v e .15,  remained  out of the c e l l .  of Freon-11  these sand  bed  in the  would not  b l o c k any composition  was  also formed in  i t should  i t shows  .20,  i t is very  should  The  optimum .20.  In  practical hydrate  former  be t h a t p r e d i c t e d by t h e  used.  to  maximum  by t h e r e s u l t  For a g r e a t e r p e n e t r a t i o n of  bore  the  needed  of emulsion  any  to  concentra-  the a d d i t i o n a l volume of  This is supported  used.  that  difficult  run i n which o n l y the c e l l  be  the  be r e a l i z e d t h a t f o r a  a c t u a l volume of hydrate  formula.  from  of  of  the high c o n c e n t r a t i o n  formation  amount  l o s t but would a c t to b l o c k more o f  formation  was  the  required less Freon-11  be u s e d w o u l d be a b o u t  blocking cases,  The  hydrate  that  the t r u e  in t h i s set of experiments  formation,  tion that should  formation.  be n o t e d  used  cell.  o b t a i n a homogeneous emulsion.  former  fraction  A c t u a l l y only a fraction  volume f r a c t i o n of g r e a t e r than  formation  Freon-11 volume  It should  higher concentration of emulsion  to  Freon-11  r e q u i r e d to fill the v o i d spaces  Although  b l o c k the sand  A m a j o r i t y of the  does not r e p r e s e n t  of the c e l l .  v o l u m e s was  that for  the amount of Freon-11  r e q u i r e d b e c a u s e gas  the void spaces  g r e a t e r than  As t h e  relatively constant.  volume of Freon-11 used  was  of  volume  h o l e , a more d i l u t e e m u l s i o n  the would  73 5.7  Possible Effect of All  Pressure  the experiments  out at atmospheric  i n t h i s study have been  pressure.  Because of the l i m i t a t i o n  t h e e q u i p m e n t , r u n s c o u l d n o t be p e r f o r m e d sures.  However, based  hydrate,  i t was  on t h e p h a s e d i a g r a m  t h e same d e g r e e  nucleation temperature  will  of  be  the  higher.  r e s u l t of this study  answers the q u e s t i o n s  to  Thus  of subcooling,  hydrate  suggested  formed  e l i m i n a t e the p e r m e a b i l i t y o f sand  technique  pres-  Freon-11  A p p l i c a t i o n to the C o n s o l i d a t i o n of Porous  s u i t a b l e c o n d i t i o n s , gas may  at elevated  of formation of the hydrate.  a t h i g h e r p r e s s u r e and  The  of  b e l i e v e d that higher pressure would help  r a i s e the temperature  5.8  carried  Formation  that  in soil  under  formation  formations.  It  r a i s e d f o r the a p p l i c a t i o n of  in c o n s o l i d a t i n g underground  this  water-bearing  formati ons. Subcooling the s o i l  formation.  where the temperature  of about  Thus Freon-11  hydrate  t e t r a h y d r o f u r a n and  hydrogen  c o u l d be u s e d  formers,  A suitable  like a mixture  s u l p h i d e would allow  A f t e r the hydrate  the formation  temperature  block in places  t o be a p p l i e d t o p l a c e s w i t h a t m o s p h e r i c  t u r e above 15°C. melt until  r e q u i r e d to  does not r i s e above 3°C.  c h o i c e o f o t h e r gas  technique  5 ° C was  i s formed,  of this tempera-  i t will  i n c r e a s e s to the  not hydrate  74  decomposition temperature hydrogen  (and f o r t e t r a h y d r o f u r a n and  sulphide hydrate, that temperature  Probably, hydrogen environmental  i s 21°C).  s u l p h i d e c o u l d n o t be u s e d b e c a u s e  reasons, although s o l i d hydrogen  s h o u l d n o t c r e a t e any e n v i r o n m e n t a l p r o b l e m s .  of  sulphide However, o t h e r  " h e l p " g a s e s c o u l d be u s e d t o s t a b i l i z e t h e h y d r a t e s h o u l d s u c h a h i g h t e m p e r a t u r e be The c r y s t a l m a t e l y two h o u r s . f o r m e r t o be pumped  growth  drilling will  p e r i o d was f o u n d t o b e a p p r o x i -  T h i s gives s u f f i c i e n t time f o r the hydrate underground  area around the i n j e c t i o n of i n j e c t i o n  needed.  points will be m i n i m a l .  and to d i f f u s e  point.  to a l a r g e  T h i s means a s m a l l  be n e e d e d  number  and thus the c o s t of  However, f u r t h e r study i s needed  to d e t e r m i n e the number and l o c a t i o n s o f i n j e c t i o n  points  that are required. The  r e s u l t o f t h i s s t u d y a l s o shows t h a t t h i s  t e c h n i q u e may b e u s e d i i i d i f f e r e n t different unlikely  sand s i z e s .  Although  t y p e s o f f o r m a t i o n have n o t been s t u d i e d , i t i s t h a t d i f f e r e n t media would  h a v e much e f f e c t on t h e  formation of hydrate unless they contained a p p r e c i a b l e concentrations of salts. F i n a l l y , the amount o f hydrate- f o r m e r r e q u i r e d i s a p p r o x i m a t e l y t h e amount o f agent i n t h e i d e a l crystal.  hydrate  H e n c e , a f t e r an a g e n t i s c h o s e n f o r t h i s t e c h -  n i q u e , t h e amount o f a g e n t r e q u i r e d c o u l d be d e t e r m i n e d very  easily.  75  The for  r e s u l t s of t h i s work c o n f i r m s P i n d e r ' s  u s i n g gas h y d r a t e s to c o n s o l i d a t e w a t e r - b e a r i n g  formation  [ 4 ] a n d t h e p r o p o s a l o f E v r e n o s \ et  eliminating mation. tion  the p e r m e a b i l i t y of porous  I t has  been  bed behaves  thermodynamic p r o p e r t i e s . as t h e p h a s e mixtures of  diagram  the expensive  may  be u s e d  To s o m e e x t e n t , i t may  forma-  The  The  long  or choice  environment. to r e p l a c e  in construction.  be a p p l i e d i n c a s e s w h e r e  i s not f e a s i b l e .  the hydrate formers  be u s e d  f r e e z i n g of soil  a t t r a c t i v e in areas near underground  present.  instead.  depend upon the p h y s i c a l  artificial  for-  a s p r e d i c t e d by i t s  g e n e r a l , t h i s t e c h n i q u e may  freezing of soil  hydrate  H e n c e i t i s b e l i e v e d t h a t as  of hydrate formers  In  [5] f o r  i s known, o t h e r h y d r a t e f o r m e r s  hydrate former would  porous  m e d i a by h y d r a t e  found t h a t the Freon-11  i n pores of sand  al.  proposal  artificial  method i s e s p e c i a l l y  gas  reservoirs since  l i k e methane or propane  are already  Chapter SUMMARY AND  A two-inch cell  of one-inch  hydrate  sand  6  CONCLUSION  bed c o n t a i n e d  diameter  was u s e d  i n a high  to study the e f f e c t of  f o r m a t i o n on t h e p e r m e a b i l i t y o f sand  F r e o n - 1 1 was c h o s e n  as t h e h y d r a t e  forming  of i t s ease o f f o r m a t i o n a t atmospheric Laboratory  tests performed  s u i t a b l e c o n d i t i o n s a gas h y d r a t e formations  have shown t h a t  its  under  bed.  The  pressure  necessary  t o be f o r m e d a n d t o b l o c k t h e conclusions  on t h e r e s u l t s o b t a i n e d t o d a t e :  A s u b c o o l i n g o f about hydrate  (ii)  because  pressure.  e f f e c t i v e l y were e x p l o r e d and s e v e r a l  may b e d r a w n b a s e d (i)  agent  c a n be f o r m e d i n s a n d  o f o v e r 1000 p s i a a c r o s s a t w o - i n c h  pores  formation.  and t h a t they can s u s t a i n a h y d r a u l i c  conditions f o r a hydrate  pressure  formed i n sand  5°C i s r e q u i r e d f o r t h e pores  to eliminate  permeability  Once t h e h y d r a t e  i s formed i n the pores, i t  can s u s t a i n high p r e s s u r e  76  ( o v e r 1000  psia)  77  even a t a temperature  much h i g h e r t h a n t h e  formation temperature.  I t melts at i t s  dissociation (iii)  temperature.  After the hydrate former the sand  i s injected  bed, i t takes about  the c r y s t a l  into  two h o u r s f o r  t o grow t o s i z e l a r g e enough t o  block the pores o f the sand bed. (iv)  Hydrate  c a n be f o r m e d i n s a n d b e d s c o f  various  sizes.  Pore s i z e does n o t have a marked  e f f e c t on t h e f o r m a t i o n o f t h e h y d r a t e . (v)  The amount o f h y d r a t e r e q u i r e d mately  that of the ideal  hydrate.  i s approxi-  composition of the  H e n c e i t c a n e a s i l y be  determined  f r o m t h e maximum c o m p o s i t i o n f o r m u l a o f a selected  The  hydrate.  hydrate formation process i n  o f a sand  p o r e s  bed b e h a v e s a s p r e d i c t e d by t h e t h e r m o d y n a m i c p r o p e r t i e s o f the hydrate.  Hence any h y d r a t e former o r m i x t u r e  f o r m e r may b e c h o s e n  f o r this technique of soil  t i o n t o make i t s u i t t h e p h y s i c a l  environment,  of hydrate consolida-  although  F r e o n - 1 1 g a s h y d r a t e was t h e o n l y g a s h y d r a t e u s e d study.  in this  78  The construction situ.  may  Besides  hydrates not  expensive  artificial  be r e p l a c e d being  f r e e z i n g of s o i l  by g a s  hydrate  true of i c e .  in regions  Thus t h i s technique  of high  formation  more s t a b l e a t h i g h e r  also remain stable at higher  pressure  in  temperatures,  pressures may  during  which  a l s o be  where a r t i f i c i a l  gas  is  applied  freezing is  not  feas ible . The hours allows f r o m one  length the  hydrate  injection Laboratory  fundamental  of c r y s t a l growth period  studies  f o r m e r to d i f f u s e to l a r g e  several  to e s t a b l i s h t h a t gas  includes  d i f f u s i o n rate of hydrate heat  the e f f e c t of s o i l the  the  controlling conditions  d u c t i v i t y and  strength  and  area  t e s t s p e r f o r m e d to d a t e have o n l y  this technique  These conditions  two  point.  in porous media e l i m i n a t i n g However, before  of about  hydrate  permeability may  still  growth rate,  former in porous rock, o f gas  hydrate-sand  c h a r a c t e r i s t i c s on h y d r a t e  s t a b i l i t y o f the gas  form media.  in large  r e m a i n s t o be  the hydrate  capacity  may  of the  be a p p l i e d  been  the  scale,  studied. the con-  system, formation  hydrate-sand  and  system.  Chapter 7 RECOMMENDATIONS FOR FURTHER STUDY  The m e c h a n i c a l rock system  s t r e n g t h o f the gas  hydrate-porous  s h o u l d be f u r t h e r i n v e s t i g a t e d . A  c o r e o f g a s h y d r a t e - s a n d f o r m a t i o n may  be  formed  in the e q u i p m e n t used f o r t h i s work and  then  may  testing  be t r a n s f e r e d t o a s o i l  compression  apparatus f o r strength analysis. The  h e a t c o n d u c t i v i t y and  heat c a p a c i t y of  the  gas h y d r a t e r s a n d f o r m a t i o n i s n e c e s s a r y f o r actual  field  design purposes.  Such a study  on v a r i o u s g a s h y d r a t e - s a n d f o r m a t i o n s s h o u l d be m a d e l t o The  o b t a i n the necessary i n f o r m a t i o n .  crystal  r o c k and in porous  growth rate of hydrate in  the d i f f u s i o n r a t e of hydrate r o c k s h o u l d be d e t e r m i n e d  porous former  in order  t h a t t h e l o c a t i o n o f i n j e c t i o n p o i n t s be determined  in actual practice.  79  REFERENCES  [1]  D a v y , H., P h i l . T r a n s . R o y . 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(1965 ).  NOMENCLATURE  a  A c t i v i t y of water water as s t a n d a r d  in a salt solution with state  C  Host component o f a c l a t h r a t e  Dp  particle  pure  compound  diameter  M d _ f  E f f e c t i v e meancdcifamektereofgguestmmcHl e c u ! e , M, i n a c l a t h r a t e compound  f  Fugacity of hydrate forming agent p h a s e w i t h Sa;lt s o l u t i o n p r e s e n t  G  Mass  g „c  dimensional  AH  Heat o f f o r m a t i o n o f gas  L  Length  M  Guest  m  Maximum number o f M m o l e c u l e s t h a t c o u l d b e accommodated i n a s i n g l e c e l l  n  Number o f m o l e c u l e s o f w a t e r agent i n gas hydrate  3  T  i n the vapor  Flowrate constant  o f porous  hydrate  bed  component o f a c l a t h r a t e  Temperature  87  compound  per moles of  88  AP  Pressure drop across porous  R  Gas c o n s t a n t  V  S u p e r f i c i a l f l u i d v e l o c i t y (measured tube b a s i s ) through a bed o f s o l i d s  1/a  Darey's  e  Poros ity  X  Shape F a c t o r  y p  permeability factor  ViscosityofFluid Dens i t y o f F l u i d  media  on an  empty  APPENDIX A  SUMMARY OF PROPERTIES OF COMMON GAS HYDRATES AND HYDRATE FORMERS  T a b l e s V I I I and gas h y d r a t e s and  IX l i s t  t h e p r o p e r t i e s o f common  the hydrate formers.  are those formed from pure s i n g l e agent  The and  hydrates  listed  water.  Unless otherwise s p e c i f i e d , the source of data i s from Suwandi's r e p o r t [15].  89  90  Table Properties  VIII  o f Common H y d r a t e F o r m i n g A g e n t s  Agent Solubility in Heat o f Liquid H 0 a t C r . S o l ution at Den s i t y Agent D e c o m p . T e m p , C r . Decomp. Normal at Normal a n d P r e s s . T e m p , and Boiling B.P. o r ( w t . % ) o r a t P r e s s , or at a t Temp. (°C) s t a t e d c o n d i t i o n s t a t e d c o ndition ;stated a n d d i m e n s i o n ( c a l / g m ole) (q/cm ) 2  Agen t  3  1. M e t h a n e (CH,) 2. A c e t y l e n e (C H ) 2  3.  2  Ethylene (C H,) 2  4. E t h a n e (C H ) 2  5.  -83.6  6  0 . 415" " 16  0.618"  8 2  * 0 . 0 9 7 ^d, p . n  -94  0.546  0 . 0 6 2 °d . p .  0.615  0.083°  3 .  n  7. P r o p a n e (C H )  -45  0.58  0.06  8. I s o - B u t a n e (i-CHxo)  -11.6  0.593  negli gi b l e  .  P  d. . l  6 4 3 9 °d . p . n  7 9  6  8  1  4981 -  £  0 . 72"  3  6  P  0.139  6. C y c l o p r o p a n e - 3 3 (c-C H ) 3  5  4 4 7 6  n  0.567  -47.7  4  1 . 1 °d . p .  -103.7  6  Propylene (C H ) 3  -161.5  CONTINUED  91  Table VIII (Continued) Agent Solubility in Heat of Liquid H 0 a t C r . S o l ution at Den s i t y Agent D e c o m p . T e m p , C r . Decomp. Normal at Normal a n d P r e s s . T e m p , and B o i l i n g B.P. o r ( w t . % ) o r a t P r e s s , o r at a t Temp, (°C) s t a t e d c o n d i t i o n s t a t e d c o n dition stated a n d d i m e n s i o n ( c a l / g m o le) (g/cm ) 2  Agent  3  9. F - l l (CC£aF) 10.  23.8 [32]  1. 46 [15] 1 . 0 6 X 1 0 " "*: p s i.a ' at 2°C [ 3 2 ] 5  f  r  F-12 (CC£ F )  -29.8  1 .49  F-12B1 (CC£F Br)  -3.89  1 .91  0.34  F-12B2 (CF Br )  24.5  1 4 . F - 2 0 ( C H C £ ) '"61 .2 Chioroform  1 .41  4.75  11,148  15.  1 .40  1 .82  8,430  2  11.  2  2  12.  2  13.  2  F-13B1 (CBrF )  -57.8  3  3  F-21 (CHC£ F)  8.92  2  16.  F-22  (CHCJoF)  -40.8  1 .27  -14.5  1 .90  2  17.  F-22B1 (CHBrF ) 2  7.08X10"  4  wt  'p s!i ar  CONTINUED  92 Table VIII  (Continued)  Agen t Solubi1ity in Heat o f Liquid H 0 a t C r . S o lution at Dens i t y Agen t D e c o m p . T e m p , C r . Decomp. a t Normal Normal a n d P r e s s . T e mp, a n d B o i 1 i ng B.P. o r ( w t . % ) o r a t P r e ss. or at a t Temp, (°C) s t a t e d c o n d i t i o n s t a t e d condition sta ted a n d d i m e n s i o n ( c a l/g-mole) (g/cm ) 2  Agen t  3  18.  F-30(CH C£ ) Methylene C h i o r i de 2  2  19. F-31 (CH C£F)  41 .4  1 . 29  7.8  9,430  -8.9  1 . 21  4.17  6,244  2  20.  F-32(CH F ) Methylene Fluoride  -51.6  1.15  21.  F-40(CH C£) Methyl Chloride  -23.7  1 .03  2.94  5,867  22.  F-40Bl(CH Br Methyl Bromi de  1 .72  2.87  6,735  1 . 38  8,131  0.045  6,970  2  2  3  3  23. F-41 ( C H F ) Methyl Fluoride 3  24.  Methyl Iodide (CH I )  3.65  -78.4  0.8.43 -  42.5  2.28  50  2 0  3  25.  F-l42b (CH CC£F ) 3  -10  1 .23  2  CONTINUED  93 Table  VIII  (Continued)  Agent Solubility in Heat o f Liquid H 0 a t C r . S o lution at Dens i t y Agent D e c o m p . Temp, C r . Decomp. Norma 1 a t Normal a n d P r e s s . T e mp, a n d B.P. o r Boiling ( w t . % ) o r a t P r e ss, or a t a t Temp, C°c) s t a t e d c o n d i t i o n s t a t e d condition stated a n d d i m e n s i o n ( c a l / g -mole) (g/cm ) 2  Agent  3  26.  F-150a (CH CHC£ ) 3  27.  57  1.16  4.3 x 1 0 "  F-152a (CH CHF )  -24.76  1 .194  0.16  28. F - 1 6 0 (C H C£) Ethyl C h i o r i de  13.1  0.905  0.447°  29. F-160B1 (C H Br) Ethyl B r o m i de  38.4  1 .46  1 .056°  2  2  30.  2  5  2  9,704  5  2  5  F-161(C H F) -37.7 Ethyl Fluoride 2  5  31. F-1140 (CH =CHC£) Vinyl Chi o r i de  -13.9  32.  -185.7  2  Argon (A)  33. A r s i n e (AsH )  20  1 .226  1.096° d VP•  -55  3  CONTINUED  3,749° d. p.  94 Table  VIII (Continued)  Agent Solubility in Heat o f Liquid H 0 a t C r . S o lution at Agent Den s i t y D e c o m p . T e m p , C r. Decomp. Normal a t Normal a n d P r e s s . T e mp, a n d B o i l i n g B.P. o r ( w t . % ) o r a t P r e a t T e m p . s t a t e d c o n d i t i o n s t a t e d s s c, o nod ri tai to n (°C) stated and d i m e n s i o n (cal/g-mole) (g/cm ) 2  Agent  3  34.  Bromine (Br )  59  Bromine Chloride (BrC£)  5  2  35.  36. C a r b o n Dioxide  -79  (co )'  2.928  1 .01  37°  5.36  8,487  6.1  4,026  2  37.  Chlorine (C£ )  -34.0  2.64  2  38.  Chlorine D i o x i de (C£0 )  2.76  10  1 0  - 2  , 7 W t .  f r . a t 0°C and 1 atm.  2  39.  x  21,291  Hydrogen Sulfide(H S)  -60  Hydrogen Selenide (H Se)  -41 . 5  2.00  -152. 3  2.155  7.3  4,076  2  40.  2  41. K r y p t o n (Kr)  1.2 x I O " " w t . f r . a t 22.5°C and 1 atm. 0.724° d. p . CONTINUED  5,015° d.p.  95 Table  VIII  (Continued)  Agent Solubi1i ty in Heat o f Liquid H 0 a t C r . S o lution at Dens i t y Agent D e c o m p . T e m p , C r . Decomp. Norma 1 a t N o r m a l a n d P r e s s . T e mp, a n d B o i 1 i ng B.P. o r ( w t . % ) o r a t P r e ss, or at a t Temp, (°C) s t a t e d c o n d i t i o n s t a t e d condition stated a n d d i m e n s i o n ( c a l / g -mole) (g/cm ) 2  Agent  3  42.  Methyl HydroSulfide (CH HS)  6  3  43.  Nitrogen (N )  -196.8  0.8081  0.41^  3,726  2  44.  Nitrous Oxide (N 2 0)  -88.5  45.  Oxygen  46.  Phosphine (PH )  -87  Sulfur D i o x i de (S0 ) S u l f u r Hexafluoride (SF )  (0 2 )  -183  d. p .  1 .149  0 .73  -10  1 .434  °- 3°i  -63.8  1 .88"  £  3  47.  1 5  2  48.  5 1  6  CONTINUED  £  6,036° d . p. 4,008  £  96  Table  VIII  (Continued)  Agent Solubility in Heat o f Liquid H 0 a t C r . S o lution at Agent Dens i t y D e c o m p . T e m p , C r . Decomp. Norma 1 a t Normal a n d P r e s s . T e mp, a n d B o i 1 i ng B.P. o r ( w t . % ) o r a t P r ess, or a t a t Temp, (°C) s t a t e d c o n d i t i o n s t a t e d condition stated a n d d i m e n s i o n ( c a l / g mole) (g/cm ) 2  Agent  3  49.  SulfurylChloride  69.1  (S0 CJo ) 2  50.  1.667  3 0  2  Stibine (SbH )  -17.1  2 . 26"  Xenon (Xe)  -107  3.52  2 5  3  51.  Superscript Subscript  Subscript  5985° d . p.  means t e m p e r a t u r e i n °C  means p r e s s u r e  Superscript  0.192° d . p.  i n atm.  I means e v a l u a t e d  a t lower i n v a r i a n t  d.p. means a t d e c o m p o s i t i o n  pressure  point  o f 0°C  Table  IX  P r o p e r t i e s o f Common Gas Hydrate Composi t i o n moles H 0 moles agent  Agent  2  Hydrate Crystal Structure/ Lattice Constant ( i f any)  Ca1cula ted Crystal Densi ty (g/cm ) 3  1.  Methane (CM  7.18  I  0.915  2.  Acetylene (C H )  5.7  I  0.989  Ethylene (C H„)  7.0  I  0.964  2  3.  2  2  Hydrates Hy d r a t e Cri ti cal Decom pos i t i o n Temp. P r e s s . (mm Hg) (°C)  Hydrate Decomp. Pressure a t 0°C (mm Hg) 19,760  16  4,332  Hydrate Decomp. Tempera t u r e a t 1 atm (°cj  Heat of R e a c t i o n f o r M(g) + nWU) = H / kcal \ g-mole  -29  14.5  -15.4  15.  14.870^ C  4.  Ethane (C H ) 2  5.  Propylene (C H )  !7  Cyclopropane (c-C H )  8(Str.I) 17(Str.II)  3  6.  8  3  7.  6  0.958  14.5  II  0.895  0.958  4508  17.0  4470  I & II  I: II:  1.03 0.895  3,952  -15.8  1 7 . 796*  Str.  I: II:  17.95  II  0.88  5.7  4140  32.103  Iso-Butane (i-C„H )  17.5  II  0.93  1 .88  1256  28.9  16.6  II  1.15  8.28  656.6  35.447  15.26  II  1.13  9.9  3216  30.114  e  1 0  9. F - l l (CC£ F) 3  10.  I  Propane (C H ) 3  8.  8.25  6  F-12 (CCJl F ) 2  2  19.06 29.2 C  C  CONTINUED  c  T a b l e IX ( C o n t i n u e d )  Agent  11.  Hydra te Crystal Structure/ Lattice Constant ( i f any)  Hydrate Composition m o l e s H?0 moles agent  9.9  1272  F-1282 (CF Br )  17  II  1 .33  4.9  386  F-13B1 (CBrF )  15.6  II  1 .21  10-12  F-20 ( C H C A j ) Chioroform  17  II  1 .09  1.10  67.8  16.8  II  1 .05  8.69  761  3 2 . 0 8 0 „c  7238  2 5 . 0 9 9 „c  2  2  F-22 (CHCJIF )  12.6  F-22B1 (CHBrF )  I  1.10  2  17  II  1.12  9.87  2012  18.  F-30 ( C H C A ) Methylene Chioride 2  2  17  11/17.31  1 .004  1.85  166.3  19. F-31 (CH UF)  I  1.18  17.88  2147  1 .08  20.4  11020  1 .11  20.4  3640  8.10  2  20.  21.  22.  23.  trans.  F-32 ( C H F ) Methylene F l u o r id-e  8  I  F-40 ( C H C A ) Methyl Chioride  7.2  I trans./ 12.00  F-40B1 ( C H B r ) Methyl Bromide  7.89  F-41 ( C H F ) Methyl Fluoride  6  2  2  3  3  3  trans.  17.5  31 .86  29.417  trans.  2  17.  Heat o f R e a c t i o n f o r M(q) + nW(n) = H / k c a l y. 'g-mole  1 .22  15. F-21 (CHCH F) 16.  Hydrate Decomp. Temperature a t 1 atm (°C)  II  3  14.  Hydrate Decomp. Pressure a t 0°C (mm Hg)  16.57  2  13.  3  Hydrate Critical Decomposi t i o n Temp. P r e s s . (mm Hg) (°c)  F-12B1 (CC*F Br) 2  12.  Calculated Crystal Den s i t y (g/cm )  18.530  16.75 •  I  trans./ 12.09  1.30  14.73  1151  18.45 c  I  1.05  18  1596  18 CONTINUED  c  Table Hydrate Composition moles H 0 moles agent  Agent  2  24. M e t h y l Iodide (CH,I) 25.  F-142b ( C H 3 C C J 0 F 2 )  26.  F-150a (CH3CHCJo2)  27.  F-152a (CH CHF ) 3  Hydrate Crystal Structure/ Lattice Constant ( i f any)  IX ( C o n t i n u e d )  Calculated Crystal Density (g/cm ) 3  Hy d r a t e Cri ti cal Decom p o s i t i o n Temp. P r e s s . (mm H g )  Cc)  Hydrate Decomp. Pressure at 0 ° C (mm H g )  Hydrate Decomp. Temperature at 1 atm (°C)  Heat o f R e a c t i o n f o r M(q) + nWU) =H , kcal . ^g-mole'  17  II  1.15  4.3  175  17.18  II  1 .04  13.09  1743  17  II  1.04  1.5  70  I trans.  1.18  14.9  3270  11/17.2  0.953  4.8  590  201  31.9  II  1 .07  1 .4  166  115  38  I  1.15  8.0  2  74  31 .4 31 .11  55  29.4 19.68  28. F - 1 6 0 CC2H5CA)  17  Ethyl Chloride 29. F-160B1  (C2H Br) 5  Ethyl  Bromide (C2H F)  30.  F-161  31.  F-1140 ( C H = CHCJt) Vinyl Chloride  Ethyl 2  3 2 . Arcjon 33. A r s i n e (AsH ) 3  34.  5  Fluoride  Bromine (Br ) 2  35. B r o m i n e Chloride (BrCA)  17 8.27  8  I trans.  1 .14  22.8  1 .15  530  3.7  -42.8  1366  4.5  I  1.17  79800  6.14  I  1 .36  613  8.57  1/12.01  1 .98  I  1 .68  6  6.2  18  93  -  M  43.9 125  20.83 14  CONTINUED  T a b l e IX ( C o n t i n u e d ) Hydrate Composition moles H 0 moies agent  Agent  2  Hydrate Crystal Structure/ Lattice Constant (if any)  Calculated Crystal Densi ty (g/cm ") 3  Hydrate Critical Decomposition Temp. P r e s s . (mm H g ) (°C)  36. C a r b o n Dioxide (C0 )  7.30  1/12.04  1 .11  10.00  33744  37. C h l o r i n e  6.20  I trans./ 12.03  1.22  28.3  6390  1 .29  18.2  Hydrate Decomp. Pressure at 0°C (mm H g )  Hydrate Decomp. Temperature at 1 atm (°C)  Heat o f R e a c t i o n of M(g) + nWU) =H /kcal « g-mole' l  13.16  2  (Cii)  38. C h l o r i n e Dioxide (CH0 )  6  I  19.2739 160  15  346  8  16.5  2  39. H y d r o g e n Sulfide (H S)  6.0  1/12.00  1 .05  29.6  40. Hydrogen Selenide (H Se)  5.87  1/12.06  1 .39  30  41. K r y p t o n (Kr)  6  42. M e t h y l H y d r o Sulfide (CH HS)  6  4 3 . Ni t r o g e n (N )  6.01  2  16720  2  I 1/12.12  1 .41 1 .15  11020 12  239  -27.8  13.9  10  16.6  3  I  1 .003  12.33*  2  44. N i t r o u s (N 0)  Oxide  6  2  1/12.03  1.13  12  45. Oxygen (0 )  6.06  I  1 .03  46. P h o s p h i n e (PH )  5.9  I  1 .05  28  1 .29  12.1  7600  -19.3  14.7 11.84*  2  1216  - 6". 4  3  47.  Sulfur Dioxide ( S 0 )  8  1/11.94  1748  297  7.1  16.6  2  CONTINUED  T a b l e IX ( C o n t i n u e d )  Hydrate Compos i t i o n moles H 0 moles agent  Hydrate Crystal Structure/ Lattice Constant ( i f any)  Calculated Crystal Dens i t y (g/cm ")  S u l f u r Hexaf1uoride (SF )  1 7.02  II  1.16  SulfurylC h1 o r i de (S0 C£ )  17  II  1.13  50. S t i b i n e (SbH )  8  I trans.  1 .49  51.  6  1/11.97  1 .77  Agent  2  48.  3  Hy I r a t e C r i 11* c a 1 Decomj3 o s i t i o n Temp. P r e s s . (mm Hg) (°c) 14.0  Hydrate Decomp. Pressure at 0°C (mm H g )  Hydrate Decomp. Temperature a t 1 atm (°C)  15124  Heat o f R e a c t i o n of M(g) + nW(J>)  29. 57  6  6  49.  2  66  31  2  3  Xenon (Xe)  10.9 1140  -3.4  * S u p e r s c r i p t b means h e a t o f r e a c t i o n e v a l u a t e d a t c r i t i c a l  decomposition  S u p e r s c r i p t i means h e a t o f r e a c t i o n e v a l u a t e d a t lower i n v a r i a n t p o i n t S u p e r s c r i p t c means c o r r e c t e d  value  =  p r e s s u r e and  temperature  H  / kcal x *g-mole'  16.7  APPENDIX B  SPECIFICATIONS OF THE EQUIPMENT  1.  Constant Temperature  Bath  R e f r i g e r a t e d and H e a t e d Type  2096, Forma S c i e n t i f i c ,  Bath and  Circulator,  Inc., M a r i e t t a , Ohio.  It c o n t r o l s t e m p e r a t u r e from -15°C i s p r o v i d e d by a 6 5 0 - w a t t  stainless  steel  R e f r i g e r a t i o n s u p p l i e d by a c o p p e r c o i l refrigeration  immersion  powered  Heat  heater.  b y a 1/5 HP  unit.  B a t h V o l u m e i s 10 g a l l o n s . p r o v i d e d by a c e n t r i f u g a l  2.  to 70°C.  Internal  circulation  pump.  H i g h P r e s s u r e Pump Milroyal  D C o n t r o l e d V o l u m e Pump, M o d e l  DB1-175R,  M i l t o n Roy C o m p a n y , S t . P e t e r s b u r g , F l o r i d a . Maximum P r e s s u r e i s r a t e d a t 1000 i s v a r i a b l e f r o m 0 - 1 0 0 % by m i c r o m e t e r capacity  i s 1800  psi.  Capacity  adjustment.  Maximum  cc/hr.  Pump- g s- p o w e r e d :bya a" ,1 / ^ h o r s e p o w e r , 1 02  1 725= RPM  motor .  1 03  3.  Centrifugal Type  Pump D - l l , Eastern Industries,  Generates U.S.  Hamden , C o n n e c t i c u t .  20 p s i a t z e r o f l o w a n d 5 p s i a t  g a l / m i n pumping  6.2  water.  Pump i s p o w e r e d by a 1/8  h o r s e power, 3450  RPM  motor.  4^esBKJessSrenfransducer Type  HHD  T r a n s d u c e r , BLH  - High Line,  High D i f f e r e n t i a l P r e s s u r e  E l e c t r o n i c s , I n c . , Walham, Mass.  Maximum d i f f e r e n t i a l r a n g e  i s 0-1000 p s i d .  Maximum  l i n e p r e s s u r e i s 5000 p s i . Pressure is indicated Model  5.  by BLH T r a n s d u c e r  4 5 0 A , w i t h an o u t p u t o f 5V.  a t 2.5  Indicator,  mA.  Sti rrer GT21  Variable  F l o r a P a r k , New  Speed  S t i r r e r , G.K.  Heller  York.  A s t a i n l e s s s t e e l 2-1/4" d i a m e t e r 3-blade o n 8-3/4  shaft  s e r i e s wound  Crop.,  is driven motor.  by a 1/40  HP b a l l - b e a r i n g  paddle reversible  APPENDIX C  CALIBRATIONS  1.  Thermocouple The i r o n - c o n s t a n t a n t h e r m o c o u p l e s were c a l i b r a t e d  the  Forma  constant temperature bath. T e m p e r a t u r e was m e a s u r e d w i t h a m e r c u r y  w i t h r a n g e -1 t o 1 0 0 ° C a n d  2.  plotted  on F i g u r e  0°C t o 17°C and the  results  27.  Rotameter T h e r o t a m e t e r was c a l i b r a t e d  by c o l l e c t i n g  passing through the rotameter a t measured T h e r e s u l t was  3.  thermometer  .1° d i v i s i o n .  T h e r a n g e c a l i b r a t e d was were  with  plotted  on F i g u r e  time  water  intervals.  28.  Pressure Transducer T h e p r e s s u r e t r a n s d u c e r was  weight pressure c a l i b r a t o r T h e r e s u l t was  c a l i b r a t e d w i t h a dead  ( r a n g e 0 - 4000  plotted  on F i g u r e  1 04  psia). 29.  F i g u r e 27.  C a l i b r a t i o n curve of Freon-Constantan ( r e f e r e n c e p o i n t -0°C)  thermocouples  o  F i g u r e 28.  Calibration  curve of  rotamter.  lOh  P R E S S U R E F i g u r e 29.  Calibration  DROP,  of pressure  psid  transducer.  APPENDIX D  CALCULATION OF IDEAL COMPOSITION OF FREON-11 GAS  HYDRATE  The maximum c o m p o s i t i o n hydrate  i s CC1 F•16.6H 0 [15]. 3  2  t i o n o f Freon-11 gas h y d r a t e  formula f o r Freon-11 That  i s , the ideal  gas  composi-  i s 16.6 m o l e s o f w a t e r and  one  moles of Freon-11. S i n c e volume  f r a c t i o n s were measured  in this  experi-  m e n t , i t i s d e s i r a b l e t o know t h e a p p r o x i m a t e c o m p o s i t i o n ideal  Freon-11  hydrate i n volume  of  fraction.  D e n s i t y o f Water = 1 gm/cc D e n s i t y o f F r e o n - 1 1 = 1.46 g m / c c . M o l e c u l a r Weight of Water = 18.0 M o l e c u l a r Weight o f Freon-11 = 137.36 Hence  16.6 m o l e s o f H 0 2  = 1 8 . 0 x 1 6 . 6 gm o f = 298.8 c c . o f H 0  H 0 2  2  1 moles of Freon-11 Hence, =  the volume  94.08 +°298.8 4  =  fraction °-  = 1 3 7 . 3 6 gm o f F r e o n - 1 1 E 94.08 c c . o f Freon-11  of Freon-11  2 3 9  1 08  in ideal  Freon-11  hydrate  APPENDIX E  CALCULATION OF POROSITY AND PERMEABILITY FACTOR  The p o r o s i t y o f the f o u r sand  beds  by p r e s s u r e d r o p m e a s u r e m e n t s w i t h w a t e r bed a t known f l o w r a t e s . was  was o b t a i n e d  flowing through  Carman-Kozeny equation  the  (equation 4)  used. For each  sand  bed, the average  p a r t i c l e was taken a s the average  diameter  o f the  sand  o f t h e mesh s i z e . T h e  p a r t i c l e s were assumed t o be s p h e r i c a l .  Thepressure  drop  a c r o s s t h e bed was measured f o r d i f f e r e n t f l o w r a t e s o f water passing through 180  (-  uV  the bed.  AP  T h e n a p l o t o f (- — j  jy-z— ) was p r e p a r e d ( F i g u r e 30 P Carmen-Kozeny equation, Slope =  ( 1  g  ) versus  t o Figure 33).  -  From t h e  £ ) 2 3  The p o r o s i t y , e , was c a l c u l a t e d u s i n g a b i n a r y  search  it e r a t i o n . To s h o w t h a t t h e C a r m a n - K o z e n y e q u a t i o n  is valid i n  the c a l c u l a t i o n , t h a t i s , t h e f l o w a c r o s s t h e bed was l a m i n a r , the p a r t i c l e Reynolds  Number was c a l c u l a t e d .  109  no  F i g u r e 31.  P o r o s i t y of sand bed ( s i z e = 32-42 mesh).  F i g u r e 32.  P o r o s i t y o f sand bed ( s i z e = 42-48 mesh).  16  y  s S  '  '  '  I  I  I  I  I  2  4  6  8  1©  12  14  16  1  F i g u r e 33.  8  0  ^  x  P o r o s i t y o f sand bed (s i z e = 4 8 - 6 0 m e s h ) .  10-  3  1  Largest Particle  Size  Maximum S u p e r f i c i a l  cm  V e l o c i t y = 4.60  cm/sec  D e n s i t y of Water  = 1.0  V i s c o s i t y of Water  = 0.01671  Therefore  Re  0.06  = DvP =  * ,4.60 * 0.01671  gm/c ; c . poise  1.0  16.51  Hence the flow of water  equation  = 0.06  a c r o s s the bed  The  Darcy's  7.  A p l o t o f (- 4^)  is  laminar.  p e r m e a b i l i t y f a c t o r was versus  calculated  (—^p-) was p r e p a r e d c e q u a t i o n 7, 9  ( F i g u r e 34)  f o r each  bed.  Then from Slope = a  where the p e r m e a b i l i t y f a c t o r i s The Table  r e s u l t s o f t h e s e c a l c u l a t i o n s a r e shown i n  X.  obbtained steel  1/a.  N o t e t h a t t h e p o r o s i t y and  permeability factor  i s the average  bed and  of the sand  p l a t e of the pressure  cell.  the s i n t e r e d  115  15i  E  £  Sand  Size v 2 4 - 3 2 mesh o 3 2 - 4 2 mesh ^ 4 2 - 4 8 mesh • 4 8 - 6 0 mesh  9  U) o  o r-  7  X CL <  3 2  J  L  4  |iV F i g u r e 34. D a r c y ' s  5 S  permeability  6  7  8  _-5  x 10 " 9 f a c t o r o f sand  beds  116  Table X P o r o s i t y and P e r m e a b i l i t y Sand S i z e (mesh)  Average P a r t i c l e D i a m e t e r (mm)  Factor  Poros i t y  o f Sand  Beds  x 10 (1/cm ) . + 6  a  2  1  x 10" .•• ( c m ) a  2  24-32  0.601  0.366  0.41  2.44  32-42  0.423  0.376  0.74  1 . 35  42-48  0.323  0.366  1 .42  0. 70  48-60  0 .2 75  0.375  1 .77  0.5 7  (  APPENDIX F EXPERIMENTAL DATA  1.  Porosity  Measurements  117  118  Table XI Data f o r (Sand  Flowrate (c.c,/sec . ) 6.89 1  41 25  Porosity  Size  Measurement  - 24 32 Mesh)  Pressure Drop Across Bed (cm of Hg) 3.65 7. 50  20.42  11 . 00  9.50  5. 30  2.85  1 . 70  2 3.27  12.80  23.27  12.00  20. 90  9. 70  17.34  8.80  15 .20  7. 50  10.92  5.50  6.65  3.30  1 .90  0.90  4.27  1 .85  119  Table Data for  Porosity  (Sand  Flowrate (c.c./sec.)  XII  Size  Measurement  32-42 Mesh)  Pressure Drop Across Bed cm of Hg  18,52  18.20  7.84  8.40  2.85  3.30  11 .87  1 2.80  14.49  1 5. 30  20.42  21 .10  4.75  4.10  9.26  8.85  21 .37  1 9. 90  9.50  9. 20  7.12  7.10  14.25  13.50  10.92  10. 60  18.76  17.25  15.67  15.00  2.85  2.90  1 .42  1 . 30  5 .22  6.55  21 .85  16.40  14.96  11 . 70  8.79  7. 20  5.70  4.85  2. 37  1 .90  11 .87  9.55  Table  XIII  Data for P o r o s i t y  Measurement  (Sand Size 42-48 Mesh) Flowrate (c.c./sec.)  Pressure Drop Across Bed cm of Hg  23.75  44.1 0  20.66  39. 30  17.34  33.90  14.25  28. 40  11 .40  23.35  9. 50  1 9. 30  7.12  14. 70  4.75  9.40  2. 37  4. 50  8. 31  I 6.60  19.00  37.10  23.75  42.90  20.90  37. 30  18.52  32. 90  15.44  27.90  10.92  20. 35  7.60  14.15  4.51  8. 20  1.19  1 .55  22 .80  35.80  20.19  31 .40  16.86  26.20  1 3.06  20.65  9.26  14.95  6.65  II . 00  4.27  6.80  1 .66.  2.20  Table  XIV  Data f o r P o r o s i t y  Measurement  (Sand Size 48-60 Mesh)  Flowrate (c.c,/sec.)  Pressure Drop Across Bed cm of Hg  23.75  51 .10  29.90  45. 70  18.52  41 .90  16.39  38.1 0  13.54  31 . 00  9.97  23.70  7.12  1 6.90  3.80  9,00  1 .42  2.80  22. 32  52.50  19.47  45.00  1 7.81  42.10  16.86  35.90  23.75  49. 90  14.72  31 .50  6.17  1 3.90  3.09  6.80  11 .87  25.80  19.71  41 .10  8.07  18.10  122 2.  Consolidation  Data  Table  XV  Data f o r C o n s o l i d a t i o n Test (Sand S i z e 24-32 Mesh)  Bath Temp. (°C)  Volume o f E m u l s i on Used (cc. )  Crystal F o r m a t i on T i me (hr. )  Volume Fraction of Freon-11 in Emulsion  Maximum Pressure (psia)  Bl  1 .0  940. 0  7.50  .138  1000.0  B2  2.0  960.0  10.00  . 1 34  250.0  B3  1 .5  300. 0  4. 00  .110  1000.0  B4  1 .5  96550-  9. 50  . 1 33  1000.0  B5  2.5  935.0  2.67  .138  0.0  Run No: '  123  T a b l e XVI Data f o r C o n s o l i d a t i o n Test (Sand S i z e 32-43 Mesh)  Run No.  Bath Temp. (°C)  Volumeoof Emuls i on Us U s e d (c.c. )  Crys ta1 F o r m a t i on T i me (hr.)  1 2 3 4 5 6 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Cl C2 C3 C4 C5 C6 C7 C8 C9 CIO  2.0 2.0 2,0 3.0 1.0 4.0 4.0 3.0 2.5 1 .5 1 .5 1 .5 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 100 1 .0 1.0 1 .0 1.0 1 .0 1.0 1.0 1 .0 1.0 1 .0  1060.0 920.0 1030.0 950.0 930.0 920.0 970.0 960.0 910.0 980.0 880.0 1000.0 940.0 930.0 91 0.0 980.0 1030.0 925.0 640.0 900.0 980.0 960.0 970.'.0 945.0 960.0 1000.0 940.0 985*0 925.6 965.0 520.0 265.0 950.0 960.0 1 76.0 125.0  1 .00 1 .50 3; 25 17.50 24.00 17.00 2.50 3.00 28.00 14.00 29.00 24.00 2 3 . 00 5.50 6.00 21 .00 7.00 15.00 5.00 11 .00 6.00 22.00 6.00 6.00 10.00 3.00 4.25 9.67 2.16 3.00 6.00 1 0000 1 .50 2.50 4. 50 5.67  cn  Volume Fraction of Freon-11 in Emulsion .080 .191 . 1 76 .128 . 1 38 .106 . 1 33 .217 .200 .096 .154 .172 .174 .161 .132 .117 .106 .095 .087 .081 .072 .044 .055 .113 . 1 07 .137 . 1 30 .1 33 .140 .141 .1 21 . 1 38 .135 .129 .122 .143 CONTINUED  Maximum Pressure (psia) 60.0 70.0 1000.0 1000.0 950.0 50.0 0.0 800.0 300.0 1000.0 1000.0 1000.0 1000.0 1000.0 1000.0 300.0 600.0 500.0 500.0 900.0 200.0 300.0 0.0 900.0 0.0 200.0 400.0 1000.0 400.0 1000.0 1000.0 1000.0 200.0 1000.0 1000.0 1000.0  124 T a b l e XVI  Run No . Cl 2 Cl 3 C14 C14 C16 C17 Cl 8 Cl 9 C20 C21 U I  D2 D3 D4 D5 D6 D7 D8 D9 DIO DI 1 D12 U13 D14 DI 5 D16 D17 D18 DI 9 D20 D21  UZZ  D23 D24 D25 D26 D27 D28 D29 D30  (Continued)  Bath Temp. (°C)  Volume o f Emulsion Used (c.c. )  Crystal Formation Time (hrs. )  Volume Fraction of Freon-11 in Emulsion  Maximum Pressure (psia)  1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0  84.0 102.0 950.0 925.0 510.0 755.0 640.0 685.0 710.0 670.0 840.0 920.0 940.0 740.0 480.0 495.0 495.0 483.0 480.0 510.0 505.0 316.0 31 0.0 405.0 240.0 360.0 245.0 186.0 126.0 142.0 78. 0 112.0 1 33.0 103.0 94.0 62.0 58.0 54.0 790.0 457.0  4.00 11 .50 1 .67 11 .00 5.16 16.00 4.67 11 .00 5.00 18.00 4.00 1 3. 00 4.00 3.50 9.16 5.00 5 . OO 8.00 4.50 3.50 13.50 2.00 5.00 17.00 6.00 12.00 5.00 1 0.00 4.15 6.33 9.33 5.50 6.00 15.00 25.00 12.67 5.00 4.00 12.00 5.50  . 1 23 .081 . 1 25 .082 .081 . 075 .079 .075 .084 .084 .105 . 1 02 .108 .104 .096 . 1 30 1 ?0 .102 . 1 03 .121 . 1 26 .121 . 1 22 .125 . 1 36 .142 .158 .154 .162 .331 .231 .222 .228 .248 .289 .304 .292 .297 . 1 09 .161  300.0 250.0 550.0 1000.0 50.0 1000.0 50.0 100.0 1000.0 1000.0 1000.0 300.0 1000.0 600.0 1000.0 1000.0 i nnn n 150.0 0.0 1000.0 1000.0 0.0 100.0 300.0 150.0 1000.0 1000.0 1000.0 700.0 1000.0 500.0 500.0 1000.0 1000.0 1000.0 1000.0 1000.0 200.0 1000.0 1000.0  lf.»U  1 .0 1 .0 1 .0 1 .0 1 .0 1.0 1 .0 1 .0 1.6 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 130 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0 1 .0  125 Table  XVII  Data f o r C o n s o l i d a t i o n T e s t (Sand S i z e 42-48 Mesh)  Run No.  Bath Temp. (°C)  Volume o f Emu 1s i o n Used (c.c. )  Crystal F o r m a t i on Time !(i h v? s ) )  Volume F r a c t i on of Freon-11 in Emulsion  11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Al A2 A3 A4 A5 A6 A7 A8 A9 A10 Al 1 Al 2 Al 3 A14 Al 5 A16 Al 7 A18  .5 1 .0 2.0 2.5 3.0 3.5 3.0 3.0 3.0 1 .5 2.0 2.0 2.0 2.0 2.0  860.0 940.0 900.0 900.0 910.0 850.0 900.0 870.0 900.0 995.0 970.0 950.0 900.0 850.0 870.0 950.0 930.0 965.0 1030.0 920.0 880.0 910.0 960.0 960.0 940.0 930.0 970.0 1800.0 950.0 2000.0 980.0 1000.0 955.0 1800.0  16.00 1 1 .00 24.00 1 3.00 5.50 1 1 .50 6.00 12.00 10.00 1 3.00 2 4 . 75 24.50 10.30 24.00 13.00  .154 .126 .119 .148 . 1 39 .107 .128 .098 .087 . 159 .143 .136 .1 30 .145 .104  '6.00 3.50 2.50 7.00 3.00 5.00 4.25 7.50 10.00 3.50 4.00 11 .00 2.00 2.00 7. 50 20.00 7.00 1 2.00  .257 .208 .141 .178 .134 .156 .142 .120 .091 .103 .094 .032 .083 .083 .121 .152 .074 .104  2.0  2.0 2,0 2.0 3.0 2.0 ,1.5 1 .5 1.5 1 .5 1.5 1 .5 1.5 1.5 1 .5 1.5 1 .5 1 .5 1 .5  13.50  .  I'32  Maximum Pressure (psia) 1000.0 1100.0 660.0 1000.0 400.0 50.0 340.0 50.0 50.0 1000.0 1000.0 550.0 240.0 150.0 800.0 1100 . 0 1000.0 1000.0 400.0 1000.0 1000.0 1000.0 1 0 0 0 .0 1000.0 50.0 300.0 100.0 1000.0 80.0 1000.0 900.0 1000.0 300.0 1000.0  126  Table  XVIII  Data f o r C o n s o l i d a t i o n T e s t (Sand S i z e 48-60 Mesh)  Run No.  Bath Temp.  Volume o f E m u l s i on Used (c.c. )  7  1 .0  970.0  8  1.0  9 10  Crystal F o r m a t i on Time (hrs. )  Volume Fraction of Freon-11 in Emulsion  Maximum Pressure (psia)  5.00  .117  1000.0  970.0  6.25  •:. 1 3 3  1000.0  2.0  960.0  6.33  .191  540.0  3.0  960.0  4.50  .150  0.0  (°c)  

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