Pyrolysis Kinetics of Several Key World Oil Shales - American

14

P y r o l y s i s K i n e t i c s of S e v e r a l K e y World Oil S h a l e s

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on February 12, 2016 | http://pubs.acs.org Publication Date: August 1, 1983 | doi: 10.1021/bk-1983-0230.ch014

1

2

H. E. NUTTALL, TIAN-MIN GUO, SCOTT SCHRADER, and D. S. THAKUR

The University of New Mexico, Department of Chemical and Nuclear Engineering, Albuquerque, NM 87131

World oil shales vary widely in geological age and genesis; thus, it is not surprising that there are substantial differences in their thermal processing behavior. To understand and quantify how these differences affect processing charactersitics, a comparative study of several key international oil shales was performed. Information is presented on the geology, organic composition, minerology, and pyrolysis kinetics. Thermal decomposition was studied through a series of nonisothermal gravimetric analyses. The TGA data were analyzed and compared using kinetic models by Coats and Redfern, Chen and Nuttall, and Anthony and Howard. Oil shales from Australia (Rundle), Brazil (Irati), China (Fushun and Maoming), USA (Green River Formation), Israel (Zefa-Ef'e), Morocco (Timhadit), Sweden (Naerke), and Yugoslavia (Aleksinac) were investigated. Anticipating a future shortage of petroleum and acknowledging the uncertainty of continuing to obtain this vital resource from some of the major petroleum producing countries have caused an increased world interest in the extraction of liquid fuels from oil shale. This interest is evidenced by the exploration for new deposits, réévaluation of known deposits, new research studies of oil shale conversion, and the development of new retorts and retorting technology. However, there has been l i t t l e , if any, 'Current address: Purdue University, Chemical Engineering Department, Lafayette, IN 47907 ^Current address: Texas A&M University, Department of Chemistry, College Station, TX 77843

0097-6156/ 83/0230-0269S09.00/0 © 1983 American Chemical Society In Geochemistry and Chemistry of Oil Shales; Miknis, Francis P., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1983.


270

GEOCHEMISTRY AND CHEMISTRY OF OIL SHALES

work to date which attempts to i n t e g r a t e an understanding of o i l shale geology, chemistry, and p r o c e s s i n g technology f o r the many d i f f e r e n t world o i l s h a l e s . I f o i l shale p r o c e s s i n g i s to proceed on an i n t e r n a t i o n a l s c a l e , a b e t t e r understanding of the major d i f f e r e n c e s among key world o i l shales must be achieved; t h i s study i n v e s t i g a t e s some of these d i f f e r e n c e s . Factors considered i n t h i s study i n c l u d e the geology and the l o c a t i o n of d e p o s i t s ( g e o l o g i c a l age, o r i g i n , extent of d e p o s i t ) , shale grade, composi t i o n of the s h a l e , and the k i n e t i c behavior of the shale upon thermal decomposition. I n i t i a l l y an e x t e n s i v e l i t e r a t u r e search was conducted to i d e n t i f y key world o i l s h a l e s , i . e . , deposits of l a r g e s i z e and/or of current i n t e r e s t to p o t e n t i a l developers. The r e s u l t i n g i n f o r mation was used to s e l e c t a few key world o i l s h a l e s . T h i r t e e n o i l shale samples from e i g h t d i f f e r e n t c o u n t r i e s were s t u d i e d . Samples were a c q u i r e d from each of the f o l l o w i n g c o u n t r i e s : Australia, Brazil, Israel, Sweden, the U n i t e d S t a t e s , and Y u g o s l a v i a . Two samples were acquired from Morocco and f i v e sam ples were acquired fr^nj the People's Republic of China. F i s c h e r , U l t i m a t e , Rock-Eval, C Nuclear Magnetic Resonance Spectroscopy (NMR), and X-ray D i f f r a c t i o n M i n e r a l analyses were performed on the samples to i d e n t i f y t h e i r c o m p o s i t i o n a l c h a r a c t e r i s t i c s . An important e f f o r t i n t h i s i n v e s t i g a t i o n was the thermal decomposition study of the s h a l e s . Considerable e f f o r t has been made to f i n d a simple k i n e t i c model which w i l l a c c u r a t e l y d e s c r i b e the weight l o s s curves f o r non-isothermal p y r o l y s i s at v a r i o u s heating rates. I n the past, many researchers have proposed and t e s t e d t h e o r e t i c a l k i n e t i c models f o r t h i s r e a c t i o n 0 - 4 ) , how ever, most attempts at f i n d i n g a s u i t a b l e model have been focused on f i n d i n g a very accurate f i t to experimental data. Successive s t u d i e s have i n c r e a s i n g l y emphasized m i c r o s c o p i c d e t a i l s ( i . e . , d i f f u s i o n models, exact chemical composition, e t c . ) i n an attempt to f i n d a p r e c i s e model to f i t the weight l o s s curves. In this study, we have s t r e s s e d that the k i n e t i c model should be both simple to use and a c c u r a t e , thus a l l o w i n g easy, r e l i a b l e a p p l i c a t i o n of k i n e t i c i n f o r m a t i o n to process design. Two proposed mechanisms were t e s t e d : a s i n g l e - s t e p mechanism: kerogen *· products and a two-step mechanism: kerogen + bitumen *· products. Three k i n e t i c models were t e s t e d : the Chen-Nut t a l l model (_5) and the Coats-Redfem model ( 6 ) ; both assume a s i n g l e f i r s t order r a t e equation to d e s c r i b e the decomposition r e a c t i o n ; and the Anthony-Howard model (7) (as developed f o r c o a l decomposition s t u d i e s ) , which assumes m u l t i p l e p a r a l l e l f i r s t order r e a c t i o n s t o d e s c r i b e the decomposition r e a c t i o n . The f o l l o w i n g m a t e r i a l b r i e f l y describes the g e o l o g i c a l and chemical c h a r a c t e r i s t i c s of each o i l shale sample and presents the r e s u l t s of the non-isοthermal k i n e t i c s t u d i e s .

In Geochemistry and Chemistry of Oil Shales; Miknis, Francis P., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1983.

14.

NUTTALL ET AL.

World Oil Shales

271


Summary of Deposits AUSTRALIA: Swarbrick (8) discusses many of the o i l shale d e p o s i t s of Queensland. The sample used i n t h i s study was obtained from the Rundle or Narrows Bed deposit near Gladstone on the P a c i f i c coast of Queensland. This d e p o s i t , discovered i n the e a r l y 20th century during dredging operations i n the Narrows between C u r t i s I s l a n d and the mainland of Queensland, i s not cons i d e r e d to be economically recoverable a t present, although some study of the deposit continues. The Rundle deposit i s one of the most o i l r i c h d e p o s i t s of A u s t r a l i a . The main deposit has an average t h i c k n e s s of about 70 m w i t h an overburden averaging l e s s than 20 m. The deposit covers an area of about 140 km ( 9 ) . BRAZIL: The i n t e r e s t i n o i l shale e x p l o r a t i o n i n B r a z i l has been s t i m u l a t e d by a l a c k of s u i t a b l e c o a l deposits and poor success i n o i l e x p l o r a t i o n . Although o i l shale deposits have been found i n many of the s t a t e s i n B r a z i l , the two deposits of primary commercial i n t e r e s t a r e those of the P a r a i b a V a l l e y , between Sao Paulo and R i o de J a n e i r o , and the I r a t i formation, extending through s e v e r a l of the southern s t a t e s of B r a z i l and i n t o Uraguay. E x p l o r a t i o n of the o i l shale deposits i n the P a r a i b a V a l l e y began i n the e a r l y 1940s w h i l e the I r a t i deposit was f i r s t s t u d i e d i n the mid-1950s. The o i l shale sample used i n t h i s study was from the I r a t i formation. The I r a t i formation, a very extens i v e deposit of o i l r i c h shale averaging 30 to 50 m i n t h i c k n e s s ^ i s as t h i c k as 100 m i n some areas and covers at l e a s t 2500 km (10)» A p i l o t p l a n t has been o p e r a t i n g a t Sao Mateus do S u l s i n c e the mid-1970s. The o i l shale i s rained by an open p i t method w i t h the overburden averaging approximately 30.5 m. CHINA: E x t r a c t i o n of shale o i l has been i n v e s t i g a t e d i n Fushun, L i a o n i n g , s i n c e the 1930s. At t h i s s i t e , a l a y e r of o i l shale from 70 to 190 m t h i c k o v e r l i e s a r i c h c o a l deposit ( 1 1 ) . Thus, o i l shale i s a by-product of e f f o r t s to recover c o a l by s t r i p mining. Two r e t o r t i n g p l a n t s are i n o p e r a t i o n at the Fushun mine and an a d d i t i o n a l r e t o r t i n g plant i s i n o p e r a t i o n at Moaming, Kwangtung P r o v i n c e . The o i l shale at t h i s s i t e i s a l s o mined by open p i t . These three r e t o r t i n g p l a n t s produce about 300,000 tons of shale o i l a n n u a l l y . This study used three samples from the Fushun mine, and two from the Maoming area ( J i n t o n and Yangu mines). ISRAEL: The I s r a e l i o i l shale sample used i n t h i s study o r i g i n a t e d from the Zefa-Ef'e d e p o s i t . Although e x p l o r a t i o n of t h i s deposit began as e a r l y as 1962, a comprehensive study of the deposit was not undertaken u n t i l 1973. This d e p o s i t , l o c a t e d i n Mishor Rotem, southwest of the Dead Sea, i s covered by an average overburden of 40 ra and contains approximately 570 m i l l i o n tons of shale w i t h an organic content greater than 10 percent (12). MOROCCO: There a r e three major o i l shale deposits i n Morocco: one near Tanger, one near Tarfaya, and one at Timhadit. The samples used i n t h i s study o r i g i n a t e d from the Timhadit s i t e ,



272


l o c a t e d i n the Middle A t l a s Mountains of c e n t r a l Morocco. There have been extensive s t u d i e s of the deposits at Timhadit (13) and a commercial r e t o r t i n g plant i s expected to be i n o p e r a t i o n there by 1986. The deposit averages about 90 m t h i c k w i t h an overburden of b a s a l t , limestone, and marlstone. The shale i s c u r r e n t l y mined by an open p i t method. A d e t a i l e d g e o l o g i c study has been conducted to plan f u t u r e mine layout (13). SWEDEN: Because of the lack of any petroleum resources as w e l l as very l i m i t e d c o a l resources, the government of Sweden has been i n t e r e s t e d i n the e x t r a c t i o n of i t s o i l shale deposits f o r q u i t e some time. The Swedish o i l shale sample used i n t h i s study was obtained from the Naerke r e g i o n , near the c i t y of Orebro, i n south c e n t r a l Sweden. The Naerke deposit i s one of three major deposits considered commercially e x p l o i t a b l e . The two others are O s t e r g o t l a n d , near Omberg, and V a s t e r g o t l a n d , near K i n n e k u l l e . The Naerke d e p o s i t , considered to be the most o i l - r i c h of the Swedish d e p o s i t s , has an average t h i c k n e s s of about 10 m (15). The overburden i s p r i m a r i l y limestone w i t h a maximum t h i c k n e s s of about 30 m, w i t h some areas covered by only a few meters of overburden (16). Here, open p i t raining i s considered to be the most economical method of o i l shale e x t r a c t i o n . ^ The deposits i n the Naerke r e g i o n cover an area of about 100 km (15). UNITED STATES: Over the past decade, the United States has examined a l t e r n a t i v e s to f o r e i g n sources of petroleum. Among the a l t e r n a t i v e s a v a i l a b l e to the United States i s e x t r a c t i o n of o i l from i t s vast o i l shale r e s e r v e s . I t has been estimated that 20 percent of the United S t a t e s land area i s u n d e r l a i n by organic r i c h deposits which f a l l under the d e f i n i t i o n of o i l shale (17). The most important d e p o s i t s i n c l u d e the e x t e n s i v e DevonianMiss i s s i p p i a n deposits of the Mid-West and Ohio V a l l e y as w e l l as the Permian and T e r t i a r y d e p o s i t s of the Rocky Mountains. To date, most a t t e n t i o n has been focused on the higher grade d e p o s i t s of the western United S t a t e s . The world's l a r g e s t o i l shale resource i s the Green R i v e r Formation l o c a t e d i n the t r i - s t a t e r e g i o n of Wyoming, Colorado, and Utah. This deposit contains high grade o i l shale over an area of approximately 41,400 km (17). The samples used i n t h i s study are from the U i n t a Basin i n Utah. The U i n t a Basin deposit covers an area of about 14,000 km w i t h high grade o i l shale to depths of about 300 ra. However, an area i n the southeast s e c t i o n of the b a s i n , covering about 3900 km , contains high grade o i l shale at depths of only 0 to 60 m (17). YUGOSLAVIA: The Y u g o s l a v i a sample used i n t h i s study was obtained from the A l e k s i n a c s i t e i n the S o c i a l i s t R e p u b l i c of Serbia. I n v e s t i g a t i o n of t h i s deposit began as e a r l y as 1955. The o i l shale deposit i n t h i s area ranges i n depth from 0 to 700 m below the s u r f a c e . The o i l shale seam i n the c u r r e n t l y o p e r a t i n g raine averages about 45 ra t h i c k (18). Much of the o i l shale i n t h i s r e g i o n l i e s over c o a l deposits which have been mined f o r 1

2

2

2


14.

NUTTALL ET

AL.

273

World Oil Shales

s e v e r a l decades. Since much of the o i l shale i s u n d e r l a i n by abandoned c o a l mines, research i s now centered around a p p l y i n g a modified i n - s i t u r e t o r t i n g method f o r recovery of the embedded o i l , although a p i l o t s c a l e surface r e t o r t has been operated i n the past. A summary of the p r i n c i p a l g e o l o g i c c h a r a c t e r i s t i c s of each of the deposits under c o n s i d e r a t i o n i s presented i n Table I .


Chemistry The chemical compositions of o i l shales and o i l shale kerogen have been s t u d i e d e x t e n s i v e l y (20). However, l i t t l e work has been done to i n t e g r a t e chemical composition data i n order to a i d i n the s e l e c t i o n of s u i t a b l e e x t r a c t i n g processes. I n t h i s study, f i v e a n a l y s i s methods were used to c h e m i c a l l y c h a r a c t e r i z e the samples. These methods i n c l u d e d Rock-Eval a n a l y s i s , F i s c h e r a n a l y sis, C NMR, U l t i m a t e a n a l y s i s , and X-ray d i f f r a c t i o n m i n e r a l analysis. Table I I presents the r e s u l t s of the Rock-Eval a n a l y s i s . In t h i s t a b l e , SI i n d i c a t e s the amount of f r e e hydrocarbons a l r e a d y generated i n the shale and S2 i n d i c a t e s the amount of hydrocarbons generated by the decomposition of kerogen at high temperatures. The sum of these values gives a s e m i - q u a n t i t a t i v e e v a l u a t i o n of the g e n e t i c p o t e n t i a l of the shale i n terms of both the abundance and type of organic matter present (21). S3 i n d i c a t e s the amount of CO2 formed by the decomposition of kerogen. S2/S3 i s the r a t i o of the Hydrogen Index to the Oxygen Index. The Hydrogen Index and Oxygen Index are r e l a t e d to the H/C r a t i o and 0/C r a t i o , respect i v e l y , and can be p l o t t e d i n a manner s i m i l a r to a van Krevelan p l o t . This p l o t i s presented i n Figure 1. A l s o i n c l u d e d i n t h i s p l o t are the thermal e v o l u t i o n paths of the three c l a s s e s of kerogen described by T i s s o t and Welte (21). The f i r s t c l a s s contains o i l producing kerogens that are c h a r a c t e r i s t i c a l l y r i c h i n a l i p h a t i c hydrocarbons. This c l a s s y i e l d s a higher amount of o i l than do the other c l a s s e s of kerogen. The second c l a s s of kerogens y i e l d s a higher amount of gaseous products than does the f i r s t . The t h i r d c l a s s of kerogens does not i n c l u d e any o i l shale kerogens. Figure 1 shows that the o i l shales i n t h i s study cont a i n kerogen from the f i r s t c l a s s (Type I ) w i t h the exception of the China Maoming #2 sample, which f a l l s i n the second c l a s s (Type II). As shown i n Table I I , S1/(S1 + S2) c h a r a c t e r i z e s the t r a n s formation of kerogen hydrocarbons to petroleum ( t h i s value w i l l i n c r e a s e w i t h maturation), and Tmax i s r e l a t e d to the degree of thermal maturation (21). In the Rock-Eval a n a l y s i s , Tmax i s the temperature corresponding to the maximum generation of hydrocarbons during p y r o l y s i s . Table I I I presents the r e s u l t s of the F i s c h e r , C NMR, and U l t i m a t e analyses. The f r a c t i o n of a l i p h a t i c carbon has been c o r r e l a t e d to the q u a l i t y or y i e l d of o i l from the shale (22). A l though t h i s value appears to correspond to the o i l y i e l d from the i6



Irati

Fushun

Brazil

China

Aleksinac

Yugoslavia

NA = Not A v a i l a b l e

Naerke Uinta Basin, Utah

Timhadit

Zefa-Ef'e deposit, Mishor Rotem

United States

Sweden

Morocco

Israel

Rundle, Queensland

Australia

Moaming

SITE

COUNTRY (Tertiary) (9)

210

(Tertiary)

A l l data from J a f f e (19) except as noted.

120,000

600

(Cambrian-Silurian) (Tertiary) (20)

(13)

Lacustrine (20)

(20)

Lacustrine

NA

NA 1 5000

(Cretaceous) (13)

Lacustrine (20)

Marine (20)

NA

1700

Marine (20)

Freshwater (20)

DEPOSITIONAL ENVIRONMENT

30

NA

(Tertiary)

800,000

600 (9)

AGE

(Permian)

ESTIMATED RESERVES (MILLION BBLS)

General Deposit Information

(Cretaceous)

TABLE I.



Sweden Yugoslavia

:

1

SI mg/gm

"62 mg/ gm nig/ gm 02/s;

31 01 +32

ORGANIC CARBON Tmax DICG C

HYDROGEN INDEX

OXYGEii INDEX

7.44

2.11 4.40

6 2

2.69

4

15

3.52

99-58

6.95

3

130.51 56.90 24.80

40.97

4.59 3.72

75.19 49-30

5.09 2.83

11 5

67.3b 75.67

33.31

0.74

31.91

28.31

16.57 13.26

46.51

70.90

1.5 0.75

1.29

1 -39

64.59

1.53

10

74.94

2.15

0

1 .OC

.05 .04 .15

.06

.07

.04 .05

.02

.02

: 81 . 96

0.5'''

10;:. 72

1 .76

y

.05

79.67

0.5c

46.32

1.61

.09

7

.02

27.54

235-46

2.93 0.35

79. 8' 81 .71

16

1.75 7.74

1

18.34 10.91 3.64

5.00

15.34

14.90 7.14

1 2. 36

'2.93

16.5?

8.83

1C.83 10.89

711.6 521.5 681 .3

446 433

424

819.4

649.1

504.6 690.4

521 . 0

5^9.6

627.8

524.5

736.9 750.3

415

417

419

431

435

442

445

440

438 426

8.2 6.9 20.5

25.3

22.9

30.8 52.1

11.3

8.2

3.5

6.6

27.1 3.2

sssssssss:========= ================== ========== ======== = = = = = = = = = = = = ======== = = = = = = = = ========== =:

SAMPLE NO.

= =: =

Australia Brazil China £1 Fushun ?.·*': China if 2 Fushun ,i2 China r 'f> Fushun r.'j China A4 l-ia owing //1 China *5 Maoming #2 Israel Morocco M-Zone Morocco Timhadit United S t a t e s Uinta Basin

sssss = s = = = ss:

SAMPLE

Table I I . Rock-Eval P y r o l y s i s Data


276


ι 2 3

1400.0


4

5 6 1200.0 H

7 8 9

10 11 15 16

Australia Yugoslavia Morocco Μ-Zone Morocco Timhadit Israel Sweden China Fushun #1 China Fushun #2 China Fushun #3 China Maoming #1 China Maoming #2 United States Utah #4 Brazil Irati

looo.o H

OR.

κ ο

800.0-1

OIL AND GAS

Ο ο

600,0-|

400.0Η

200.0

ΟΧ)

—ι 0.0

10.0

20.0 OXYGEN

30.0

— ι — 40.0

5O0

60X)

INDEX

Figure 1. Hydrogen index vs. oxygen index for various oil shales.



SAMPLE

16.6/6.9 15.9/6.7 8.3/3.5 14.3/6.0 6.9/2.9 15.3/6.4 14.6/6.1 11.7/4.9

3.5/1.5 NA 5.2/2.2

3.1/1.3 7.0/2.9

33.7/12.8 25.2/9.6 26.5/10.1 30.7/11.7 32.1/12.2 22.7/8.7 27.4/10.4 17.7/6.8

14.6/5.6 NA 33.0/12.5

50.4/19.1 18.6/7.1

WATER (GPT/WTJO

FRACTION ALIPHATIC CARBON

18.67/18.34 9.25/3.64

0.79 ** 0.67

1.31

2.25 1.02

1.62

2.51

0.54

*

1.02 2.61

14.98/7.14

I3.5/H.9I

NA 0.68

1.3 0.55

10.21 17.25

15.81

1.9 2.73 2.89

4.87 0.48 0.62 0.49 1.24 1.22 2.49

1.19

^SULFUR

18.14 17.42

8.73 11.41 8.33 9.86 22.75

13.65/5.00 25.74/15.34 17.28/10.91

10.51

1.96 2.71 1.93 2.85

0.65 NA NA 0.65 NA 0.68 NA 0.71

11.67 4.58

^OXYGEN

2.81 1.83

SCS535SS3BSCSSS35SS

^HYDROGEN

Information

16.45/10.83 12.85/10.70 10.73/8.83 16.61/16.53 11.14/12.93 * 14.54/12.36

S S S S 3 S S S S S S S 8 S S S X S S 3 S S S Z S S S S

CARBON T0TALÎ/20RGANIC

F i s c h e r , U l t i m a t e , and C13 NMR A n a l y s i s

NA - Not A v a i l a b l e * - note that ^ o r g a n i c C > t o t a l e C — a t t r i b u t e d to experimental e r r o r ** - approximated from values f o r Colorado Green R i v e r O i l Shale g i v e n by M i k n i s and Smith (22)

#5 Israel Morocco Timhadit M-Zone Sweden United S t a t e s U i n t a Basin #4 Yugoslavia

H

Australia Brazil China #1 #2 #3

S S S S S S S S S S S 2 S S

OIL (GPT/WT?)

TABLE I I I .




278

shales i n t h i s study, no f i r m r e l a t i o n s h i p between these values i s evident here. Further i n v e s t i g a t i o n of the s i g n i f i c a n c e of the values i n t h i s t a b l e i s planned. Table IV presents the r e s u l t s of the X-ray d i f f r a c t i o n min eral analysis. The values i n t h i s t a b l e give r e l a t i v e m i n e r a l c o n c e n t r a t i o n s . Future i n v e s t i g a t i o n s of t h i s i n f o r m a t i o n should r e v e a l whether or not the m i n e r a l c o n c e n t r a t i o n has a s i g n i f i c a n t e f f e c t on the p y r o l y s i s r e a c t i o n . I t should be noted that there i s a s i g n i f i c a n t range of d i f f e r i n g o i l shales under c o n s i d e r a t i o n i n t h i s study. This range of c h a r a c t e r i s t i c s i n s u r e s that the scope of our study w i l l be broad enough to be a p p l i c a b l e to most i n t e r n a t i o n a l o i l shale samples. Kinetics The r a t e of kerogen decomposition i n t o o i l and gaseous prod ucts can be an important f a c t o r i n process design, as can the r e l a t i v e amount of o i l and gas produced. Nonisothermal g r a v i m e t r i c a n a l y s i s was used to compare the r e l a t i v e thermal decompo s i t i o n r a t e s of the kerogens i n the shales under i n v e s t i g a t i o n . D e t a i l s of the p y r o l y s i s s t u d i e s are presented i n the f o l l o w i n g sections. Experimental S e c t i o n . The samples used i n the TGA study were crushed to minus 200 mesh. Nonisothermal weight l o s s data were gathered using a DuPont 951 thermogravimetric balance w i t h a DuPont 990 thermal a n a l y z e r . T h i r t e e n samples were analyzed using heating r a t e s ranging from 1.0 to 50.0°C/min. The samples were heated to a maximum of 500°C. This temperature was maintained u n t i l the sample weight stabilized. The f r a c t i o n of kerogen p y r o l y z e d , a, was d e f i n e d by the expression: W

- VJ ο

»

where W i s the i n i t i a l weight of sample (mg), W i s the weight of sample at time t minutes (mg), and Woo i s the weight of sample a f t e r complete p y r o l y s i s (mg). Some t y p i c a l i n i t i a l and f i n a l experimental weight r a t i o s are l i s t e d i n Table V f o r comparison. These values give an i n d i c a t i o n of the r e l a t i v e q u a n t i t y of organic matter i n each of the shales under i n v e s t i g a t i o n , and of the progress of the r e a c t i o n at 500°C. Q

t

Discussion. Over the past s e v e r a l decades, there have been many attempts to c h a r a c t e r i z e the k i n e t i c behavior of o i l shales under pyrolyzing conditions. I n 1950, Hubbard and Robinson (1)



R e l a t i v e M i n e r a l Concentrations

- X-Ray D i f f r a c t i o n

Kinerology

Continued on next page

SMECTITE ILLITE KAOLITE/CHLORITE QUARTZ K-SPAR NA-SPAR ANALCIME (6.0 -7.0°) (3.8°) (26.6°) (27.6°) (28.0°) (26.0°) (12.3 °) ==: ======================================= = s = = = s == =======:ss=====ss====================:========= Australia 6.0 Β 1 .0 ND 1 .0 60 2.0 ND 3.5 Brazil 2.0 1.5 Β 100 9.0 1.7 1.3 10.0 ND China #1 ND 1.0 5.0 ND 2.0 67 1 .0 ND #2 2.0 3.0 4.0 1.5 3 74 ND 3.5 1.5 2.0 Β 1 .0 5b 3* ND ND 2.5 TR 11* 2.0 77 1 .0 ND 5.5 2.0 Β 2.0 iï5 7.0 3.0 6.0 ND 63 ND 9 Israel 1.0Β ND 1 .0 ND TR ND ND Morocco ND Timhadit 1 .0 1.0 ND 2.0 ND 51 1.5 M-Zone 1.0 Β 1.0 ND 1.0 29 1 .0 ND 1.5 Sweden ND ND 2.5 50 3.5 4.0 ND 3.5 United States Uinta Basin 2.0 H 3.0 ND ND ND 27.0 63 ND Yugoslavia ND 1* 2.5 3.0 14 2.8 2.5 S= = = = : == ============================== s s s s s = = :s s s s s s s s s s :s s s s s s s s : = = SS = = = = ===== ===============ssss

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TABLE IV.


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