Carbon Monoxide Over Ruthenium

20 Aromatic Gasoline From Hydrogen/Carbon Monoxide Over Ruthenium/Zeolite Catalysts T. J. HUANG and W. O. HAAG

Downloaded by UNIV OF PITTSBURGH on May 4, 2015 | http://pubs.acs.org Publication Date: May 5, 1981 | doi: 10.1021/bk-1981-0152.ch020

Mobil Research and Development Corporation, P.O. Box 1025, Princeton, N J 08540

A new c l a s s o f s y n t h e s i s g a s c o n v e r s i o n c a t a l y s t s c o m p r i s i n g a c a r b o n m o n o x i d e r e d u c t i o n c a t a l y s t combined w i t h a ZSM-5 c l a s s z e o l i t e h a s b e e n r e c e n t l y r e p o r t e d b y Chang, L a n g a n d S i l v e s t r i (1). I n e l a b o r a t i n g o n t h i s f i n d i n g , C a e s a r , e t . a l . , h a v e demon s t r a t e d t h a t g a s o l i n e c a n be produced i n a y i e l d o f over 60% o f t o t a l h y d r o c a r b o n , c o n s t i t u t i n g e s s e n t i a l l y 100% o f t h e l i q u i d p r o d u c t , by combining an i r o n F i s c h e r - T r o p s c h c a t a l y s t w i t h an e x c e s s v o l u m e o f a ZSM-5 c l a s s z e o l i t e ( 2 ) . These z e o l i t e s a r e members o f t h e g r o u p o f M o b i l shape s e l e c t i v e medium p o r e z e o l i t e s w h i c h a r e a c t i v e f o r t h e c o n v e r s i o n o f methanol and o t h e r oxygen a t e s t o h y d r o c a r b o n s (1,3^,4) o r F i s c h e r - T r o p s c h r e a c t i o n i n t e r mediates t o aromatics ( 1 ) . Ruthenium has been used a s a F i s c h e r - T r o p s c h c a t a l y s t t o c o n v e r t s y n t h e s i s g a s i n t o p a r a f f i n wax u n d e r h i g h p r e s s u r e a n d a t l o w t e m p e r a t u r e ( 5 ) . However, a t h i g h e r t e m p e r a t u r e a n d l o w e r p r e s s u r e , o n l y methane i s formed ( 6 ) . S u p p o r t e d r u t h e n i u m s u c h as R u / a l u m i n a a n d R u / s i l i c a h a s a l s o b e e n u s e d f o r s y n g a s c o n v e r s i o n t o p r o d u c e g a s e o u s , l i q u i d and s o l i d h y d r o c a r b o n s ( 7 - 1 3 ) ; b u t , i t gave a p o o r s e l e c t i v i t y f o r l i q u i d h y d r o c a r b o n a n d , a g a i n , methane becomes t h e m a j o r p r o d u c t a t t e m p e r a t u r e s h i g h e r t h a n 250°C. F u t h e r e m o r e , no a r o m a t i c s w e r e p r o d u c e d u s i n g b o t h r u t h e n i u m d i o x i d e and s u p p o r t e d r u t h e n i u m c a t a l y s t . In the F i s c h e r - T r o p s c h s y n t h e s i s w i t h ruthenium as c a t a l y s t , normal p a r a f f i n s a r e the major p r o d u c t s . I n M o b i l ' s D i s t i l l a t e Dewaxing p r o c e s s , ZSM-5 c l a s s c a t a l y s t s c o n v e r t s e l e c t i v e l y h i g h m o l e c u l a r w e i g h t η-paraffins i n t o g a s o l i n e r a n g e m a t e r i a l s ( 1 4 ) . Thus, ruthenium-ZSM-5 c l a s s z e o l i t e s a p p e a r t o b e good c o m b i n a t i o n f o r g a s o l i n e p r o d u c t i o n from s y n t h e s i s gas. I n a d d i t i o n , these c o m b i n a t i o n c a t a l y s t s may p r o v i d e a " n o n t r i v i a l p o l y s t e p " r e a c t i o n (15) i n w h i c h F i s c h e r - T r o p s c h i n t e r m e d i a t e s c o u l d b e t r a p p e d a n d c o n v e r t e d i n t o a r o m a t i c s b y t h e z e o l i t e component, t h u s p r o d u c i n g h i g h o c t a n e a r o m a t i c g a s o l i n e d i r e c t l y f r o m s y n t h e s i s g a s . The s u c c e s s f u l u s e o f t h e z e o l i t e s mentioned i s a r e s u l t o f t h e unique p r o p e r t i e s o f t h i s c l a s s o f intermediate pore z e o l i t e s , o f w h i c h ZSM-5 i s a p r o m i n e n t menber. I t was c h o s e n a s a r e p r e s e n t a t i v e o f t h i s c l a s s i n the present study. 0097-6156/81/0152-0307$05.00/0 © 1981 American Chemical Society In Catalytic Activation of Carbon Monoxide; Ford, P.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

CATALYTIC

308

ACTIVATION

OF CARBON

MONOXIDE

Experimental 5% R u ( a s Ru0 )/ZSM-5 was p r e p a r e d b y g r i n d i n g t o g e t h e r t h e a p p r o p r i a t e amounts o f RuO^ a n d ZSM-5 z e o l i t e , f o l l o w e d b y p e l l e t i n g a n d s c r e e n i n g t o 30-60 mesh. I m p r e g n a t e d Ru/ZSM-5 was p r e p a r e d by vacuum i m p r e g n a t i o n o f ZSM-5 z e o l i t e ( i n NH^ form) w i t h R u C l ^ * 3 H 2 O i n aqueous s o l u t i o n . A f t e r d r y i n g i n vacuum, t h e c a t a l y s t was c a l c i n e d i n a n o v e n a t 538°C f o r two h o u r s . Ru/AÔ^//ZSM-5 was a p h y s i c a l m i x t u r e o f e q u a l amounts o f s u p p o r t e d Ru - o n a l u m i n a and ZSM-5 z e o l i t e . S u p p o r t e d Ru - o n - a l u m i n a was p r e p a r e d b y vacuum i m p r e g n a t i o n o f y - a l u m i n a w i t h R u C l ^ ^ H ^ O i n aqueous s o l u t i o n , f o l l o w e d b y d r y i n g i n a r o t a r y e v a p o r a t o r a t a b o u t 100°C and i n a vacuum o v e n a t 102°C f o r two h o u r s . P r i o r t o syngas c o n v e r s i o n , a l l ruthenium c o n t a i n i n g c a t a l y s t s were reduced w i t h hydrogen. Syngas c o n v e r s i o n was c o n d u c t e d i n a down f l o w f a s h i o n i n a f i x e d - b e d c o n t i n u o u s f l o w m i c r o - r e a c t o r . The p r e h e a t e r a n d r e a c t i o n zone w e r e made o f 1.42 cm i . d . t y p e 321 s t a i n l e s s - s t e e l tubing enclosed i n a three-zone e l e c t r i c a l r e s i s t a n c e block heater. Gas f l o w was c o n t r o l l e d u s i n g a B r o o k s I n s t r u m e n t f l o w c o n t r o l l e r . L i q u i d p r o d u c t was c o l l e c t e d d i r e c t l y i n a p r e s s u r e d J e r g u s o n s i g h t g l a s s a t ambient temperature. The e x i t g a s p a s s e d t h r o u g h a c o n d e n s e r and a G r o v e b a c k - p r e s s u r e r e g u l a t o r t o a wet t e s t m e t e r w h e r e t h e e x i t g a s f l o w r a t e was m e a s u r e d . The c o n d e n s e d h y d r o c a r b o n i n t h e h i g h p r e s s u r e J e r g u s o n s i g h t g l a s s was f u r t h e r weathered t o atmospheric p r e s s u r e . P r o d u c t a n a l y s e s w e r e c a r r i e s o u t b y gas c h r o m a t o g r a p h y .


2

R e s u l t s and D u s c u s s i o n s G e n e r a l l y s p e a k i n g , hydrogénation o f Co o n r u t h e n i u m i s s i m i l a r t o s y n t h e s i s r e a c t i o n s on c o b a l t and n i c k e l i n so f a r as t h e o x y g e n o f CO i s r e j e c t e d e s s e n t i a l l y a s w a t e r . However, s u p p o r t m a t e r i a l s may i n d u c e a s h i f t r e a c t i o n a n d may l e a d t o p r o d u c t i o n o f some C 0 . As shown i n T a b l e I I I , t h e m o l e r a t i o s o f H 0 t o C 0 i n t h e r e a c t o r e f f l u e n t w e r e 29,54,and 5 f o r Ruu«, I m p r e g n a t e d Ru/ ZSM-5, and s u p p o r t e d R u / A l 0 ~ , r e s p e c i t v e l y . This i scontrary to i r o n F i s c h e r - T r o p s c h c a t a l y s t which g i v e s C 0 as the major oxygen c o n t a i n i n g p r o d u c t . F o r example, t h e mole r a t i o o f H 0 t o C 0 i n t h e p r o d u c t f r o m s y n g a s c o n v e r s i o n o v e r i r o n c a t a l y s t s (1,5,15) i s g e n e r a l l y l e s s t h a n 0.1. T h i s d i f f e r e n c e a r i s e s from t h e f a c t t h a t i r o n i s a c t i v e f o r water-gas s h i f t r e a c t i o n (Equation I I ) w h i l e ruthenium i s not. 2 H + CO ^ (-CH -) + H 0 (I) 2

2

2

2

2

2

2

H 0 + CO 2

2

C0

2

+ H

2

2

(II)

2

For ruthenium c a t a l y s t s without s h i f t a c t i v i t y , t h e s t o i c h i o m e t r i c r e q u i r e m e n t f o r s y n g a s c o n v e r s i o n i s two m o l e s o f H p e r m o l e o f CO, a c c o r d i n g t o E q u a t i o n ( I ) . However, t h e H /C0 u s a g e r a t i o c a n be l e s s t h a n 2 when t h e c a t a l y s t h a s s h i f t a c t i v i t y ( E q u a t i o n I I ) . 2

2

In Catalytic Activation of Carbon Monoxide; Ford, P.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

Aromatic

H U A N G A N D HAAG

20.

Gasoline

Using

Ru/Zeolites

309

E f f e c t of Z e o l i t e R e s u l t s w i t h composite c a t a l y s t s c o n s i s t i n g o f a s u p p o r t e d R u / A ^ O ^ and a z e o l i t e a r e g i v e n i n T a b l e I . A l t h o u g h t h e z e o l i t e s t h e m s e l f h a v e no e f f e c t on t h e s y n g a s c o n v e r s i o n , t h e h y d r o c a r b o n p r o d u c t d i s t r i b u t i o n i s a f f e c t e d by t h e p r e s e n c e o f a z e o l i t e , p a r t i c u l a r l y o f t h e ZSM-5 c l a s s . The i n c o r p o r a t i o n o f ZSM-5 i n t h e c a t a l y s t n o t o n l y promoted a r o m a t i c s f o r m a t i o n , b u t a l s o s i g n i f i c a n t l y r e d u c e d t h e end p o i n t o f t h e hydrocarbons. The t o t a l h y d r o c a r b o n f r a c t i o n c o n t a i n e d 66 w t % o f , w h i c h was e s s e n t i a l l y an a r o m a t i c g a s o l i n e ( 3 4 % a r o m a t i c s , 204°C b o i l i n g p o i n t a t 9 0 % o v e r h e a d ) . I t must be n o t e d t h a t , w i t h r u t h e n i u m a l o n e ( E x . Ι Α ) , no a r o m a t i c s w e r e p r o d u c e d and the b o i l i n g point of C a t 90% o v e r h e a d was 322°C. The p r e s e n c e o£ a l a r g e p o r e z e o l i t e , H - m o r d e n i t e , r e d u c e d t h e end p o i n t o f o n l y s l i g h t l y . M o r e u n i t e i n i t i a l l y gave a r o m a t i c s w i t h s u b s t a n t i a l amount o f C ^ Q a r o m a t i c s , b u t i t d e activated very rapidly.


5

E f f e c t o f Ruthenium L o a d i n g Two r u t h e n i u m c o n c e n t r a t i o n s ( 0 . 5 % and 1.5%) w e r e u s e d t o s t u d y t h e e f f e c t o f r u t h e n i u m l o a d i n g on s y n g a s c o n v e r s i o n o v e r p h y s i c a l l y m i x e d Ru/AlÔ^/ZSM-S catalysts. The r e s u l t s a r e shown i n T a b l e I I . The f o r m a t i o n o f l 2 S y r e d u c e d f r o m 4 0 % w t h 1.5% Ru t o 25% w i t h 0.£% Ru. On t h e o t h e r h a n d , t h e h i g h e r r u t h e n i u m l o a d i n g gave a π p r o d u c t o f r e d u c e d end p o i n t ( E x . 2A and 2 B ) . As e x p e c t e d , no d i f f e r e n c e i n a r o m a t i c s p r o d u c t i o n was o b s e r v e d . The same e f f e c t was s e e n w i t h i m p r e g n a t e d Ru/ZSM-5 c a t a l y s t s o f 1% and 5% R u - c o n t e n t (Ex.2C and 2D). C

+

C

w a s

r e a t l

E f f e c t o f Method Of C a t a l y s t P r e p a r a t i o n T h r e e c a t a l y s t s w i t h d i f f e r e n t methods o f p r e p a r a t i o n w e r e u s e d i n t h i s s t u d y and t h e r e s u l t s a r e g i v e n i n T a b l e I I I . A l t h o u g h they have the same r u t h e n i u m l o a d i n g ( 5 % ) , t h e d e g r e e o f i n t i m a c y b e t w e e n r u t h e n i u m s i t e s and a c t i v e s i t e s o f ZSM-5 i n c r e a s e d w i t h t h e f o l l o w i n g o r d e r : I m p r e g n a t e d Ru/ZSM-5 > Ru0 /zsM-5 ( g r o u n d t o g e t h e r ) > P h y s i c a l M i x t u r e o f Ru/AlÔ^ and zSlji-5. The most s t r i k i n g f e a t u r e was t h a t t h e f o r m a t i o n o f heavy a r o m a t i c s i n c r e a s e d w i t h i n c r e a s i n g degree o f i n t i m a c y between Ru and ZSM-5, a s shown i n T a b l e I V . T h i s may i n d i c a t e t h a t i f r u t h e n i u m s i t e s and a c i d s i t e s o f ZSM-5 a r e l o c a t e d c l o s e l y t o g e t h e r as i n t h e c a s e o f t h e i m p r e g n a t e d c a t a l y s t , t h e a r o m a t i c s formed a s z e o l i t e s i t e s may be f u r t h e r a l k y l a t e d w i t h t h e r e a c t i o n i n t e r m e d i a t e s produced a t the n e i g h b o r i n g ruthenium s i t e s , c o n s e q u e n t l y making heavy a r o m a t i c s . The v a r i a t i o n s i n s y n g a s c o n v e r s i o n and C^^K^ selectively c o u l d be due t o t h e d i f f e r e n c e i n r u t h e n i u m s u r f a c e a r e a s as a result of d i f f e r e n t preparations. A f i n e l y ground p h y s i c a l m i x t u r e o f 5% Ru ( a s Ru0 )/ZSM-5 w h i c h was s u b s e q u e n t l y p e l l e t i z e d was u s e d i n t h e s t u d y o f t h e e f f e c t s o f p r o c e s s v a r i a b l e s on s y n t h e s i s gas c o n v e r s i o n . 2

2


CATALYTIC

310

ACTIVATION

OF CARBON

MONOXIDE

Table I SYNGAS CONVERSION OVER RUTHENIUM/ZEOLITE CATALYSTS AT 51 atm, 294°C, GHSV = 4 8 0 , AND H /C0 = 2/1. 2

E x p e r i m e n t No.


Catalyst

0.5% R u / A l 0 / / 2

3

Quartz Chips "Mixed" Syngas C o n v e r s i o n , mole %

1C

IB

1A

0.5% R u / A l 0 / / 2

ZSM-5 "Mixed"

3

0.5% R u / A l ^ / / H-Mordenite "Mixed"

94

98

95

37

38

36

0

0

1

11

1

6

2

6

12

8

H 0

46

49

49

33

25

29

8

9

7

59

66

63

0

34

< 5

90% Overhead

322

204

275

95% Overhead

377

224

322

Reactor E f f l u e n t , wt% Hydrocarbons H

2

CO C0 2

Hydrocarbon Composition, wt% C

l

+

C

3

+

C

C

2 C

+

4

5

A r o m a t i c s i n C,. , w t %

B o i l i n g Range o f C

+ 5

,

°C


20.

Aromatic


Gasoline

Using

Ru/Zeolites

311

Table I I EFFECT OF RUTHENIUM LOADING ON SYNGAS CONVERSION (51 atm, GHSV = 4 8 0 , AND H /CO - 2/1) 2

2A


1.5% Ru/Al.O // ZSM-5


Catalyst

"Mixed" Temp.

294

2D

2C

2B 0.5% R u / A l 0 ZSM-5 2

"Mixed"

//

1% Ru/ ZSM-5

5% Ru/ ZSM-5

"Impregnated"

"Impregnated" 304

294 304

Syngas C o n v e r s i o n , mole % 99

83

98 86

Reactor wt%

Effluent,

Hydrocarbons H

2

32

39

38

38

0

0

1

2

CO

0

1

15

18

C0

17

12

2

3

44

49

44

45

40

25

38

20

12

9

16

29

48

66

46

51

32

43

25

27

2

H 0 2


C

l

+

C

2

+ C

3 4 C + 5 C

Arom; iatics in wt% B o i l i n g Range o f

c5+,

°C

90%

Overhead

174

204

95%

Overhead

186

224


312

CATALYTIC ACTIVATION OF CARBON MONOXIDE

Table I I I

EFFECT OF METHOD OF CATALYST PREPARATION ON SYNGAS CONVERSION OVER Ru/ZSM-5 CLASS ZEOLITE.


9

3A

Catalyst

Impregnation

P a r t i c l e S i z e , mesh

( B a s e d on T o t a l

Ru0 Plus zài-5 9

Ground T o g e t h e r

Ru/Al 0 ZSM-5

30 - 60

5%

5%

5%

304

294

294

93

99

36

40

0

0

12

0

4

20

48

40

38

30

43

16

17

14

46

53

43

25

28

24

79

90

97

21

10

3

Syngas C o n v e r s i o n , mole %

86

Reactor E f f l u e n t , wt% Hydrocarbons H

38 1

2

CO C0

15 2

2

H 0

44

2


l

c C

+

3 +

5

C

c

2 4

+

Aromatics i n C

c

wt%

Aromatics D i s t r i b u t i o n wt% A

A

6" 10 "11

J

Physical Mixture

Solid)

Temp., °C

Plus

9

30 - 60

30 - 60

Ruthenium L o a d i n g , wt%

3C

3B

Ru/ZSM-5

Method o f Preparation Downloaded by UNIV OF PITTSBURGH on May 4, 2015 | http://pubs.acs.org Publication Date: May 5, 1981 | doi: 10.1021/bk-1981-0152.ch020

( 5 1 a t m , GHSV = 4 8 0 , AND H /C0 = 2/1)


20.


Aromatic

Gasoline

Using

Ru/Zeolites

313

Table IV EFFECT OF PRESSURE ON SYNGAS CONVERSION OVER 5% Ru (AS R u 0 > / 2

ZSM-5 AT 294°C, H /CO = 2/1, AND GHSV = 4 8 0 . 2

P r e s s u r e , atm.

13.6

27.2

51

75

CO

63

78

86

90

H,

77

92

96

98

29.8

35.2

35.5

37.4

H,

2.9

1.4

0.5

0.2

CO

32.6

20.8

11.8

8.8


Conversion, wt%

T o t a l Product, wt% Hydrocarbon

co

2

H 0 2

1.8

3.1

3.6

3.8

32.9

39.5

48.6

49.8

52.8

44.5

26.0

26.1

5.9

5.0

4.3

3.4

7.7

7.1

5.1

3.0

-

-

0.7

0.2

10.3

10.5

5.6

3.5

5.0

6.1

4.5

3.6

-

-

0.9

-

6.3

6.1

5.4

4.1

1.5

2.3

3.5

4.0

2.0

7.8

29.5

40.8

8.5

10.6

14.7

11.5

18.3

26.8

53.1

60.4

46.2

39.4

27.7

19.1

98.0

96.3

97.4

97.0


l

V V i-c

4

n-C

4

V i-c

5

n-C

5

non-aromatics Aromatics C + 5

i n T o t a l H.C., w t %

Aromatics

i n C^+, w t %

Hydrocarbon wt%

Selectivity,


314

C A T A L Y T I C ACTIVATION

OF CARBON

MONOXIDE

Effect of Pressure The r e s u l t s a r e l i s t e d i n T a b l e I V . The e f f e c t o f p r e s s u r e o n c o n v e r s i o n s and s e l e c t i v i t i e s a r e shown i n F i g u r e 1. The CO c o n v e r s i o n i n c r e a s e d f r o m 6 3 % a t 13.6 atm (200psig) t o 9 0 % a t 75 atm ( l l O O p s i g ) . The h y d r o c a r b o n selectivi t y , d e f i n e d as ( t o t a l carbon converted - t o t a l carbon i n C 0 ) f t o t a l c a r b o n c o n v e r t e d , r e m a i n e d s t e a d y a t 97%. t h e r e s t o f 3% b e i n g c o n v e r t e d t o CO^. The s e l e c t i v i t y o f C r + i n c r e a s e d w i t h i n c r e a s i n g pressure while t h e aromatics i n decreased. The C^+C^ make was s u b s t a n t i a l l y r e d u c e d b y h i g h e r p r e s s u r e , f o r e x a m p l e , f r o m 5 9 % a t 13.6 atm t o 2 9 % a t 74 atm.


2

E f f e c t o f Temperature Three temperatures i n t h e range o f 264 t o 328°C (507 t o 613°F) w e r e u s e d f o r t h e s t u d y o f t h e e f f e c t of temperature. The d e t a i l e d c o n d i t i o n s and r e s u l t s a r e i n c l u d e d i n T a b l e V. The p l o t s o f c o n v e r s i o n a n d s e l e c t i v i t i e s v e r s u s t e m p e r a t u r e a r e shown i n F i g u r e 2. B o t h h y d r o c a r b o n selectivity and H a n d CO c o n v e r s i o n s w e r e h i g h i n t h i s r a n g e . The s l i g h t l y l o w e r CO c o n v e r s i o n a t h i g h e r t e m p e r a t u r e c o u l d b e due t o t h e g r e a t e r y i e l d o f C ^ K ^ . The two k e y f e a t u r e s e m e r g i n g f r o m t h i s s t u d y a r e t h e s h a r p i n c r e a s e i n C^ and t h e s h a r p d e c r e a s e i n C]+C f u n c t i o n o f decreasing temperature. A t 264°C, t h e C^+C« make was r e d u c e d t o 1 1 % . No t e m p e r a t u r e l o w e r t h a n 264 *C was i n v e s t i g a t e d i n t h i s s t u d y a l t h o u g h C~ y i e l d c o u l d p o s s i b l y be i n c r e a s e d a b o v e t h e 8 9 % o b t a i n e d a t 264°C. The a r o m a t i c s i n t o t a l h y d r o c a r b o n went t h r o u g h a maximum a t 294°C. The l o w e r a r o m a t i c s s e l e c t i v i t y a t 264°C was p r o b a b l y d u e t o t h e p o o r a r o m a t i z a t i o n a c t i v i t y o f ZSM-5 a t s u c h a l o w t e m p e r a t u r e , w h i l e a t h i g h e r t e m p e r a t u r e methane f o r m a t i o n c o m p e t e s . 2

a

s

a

2

E f f e c t o f Space V e l o c i t y The d a t a a r e g i v e n i n T a b l e V I , and t h e c o n v e r s i o n a n d s e l e c t i v i t i e s a r e p l o t t e d a g a i n s t 1/WHSV i n F i g u r e 3. C l e a r l y , a t l o n g e r c o n t a c t t i m e ( o r l o w e r s p a c e v e l o c i t y ) , C^ d e c r e a s e d a n d C^+Co i n c r e a s e d . Thus t h e l a t t e r appear t o be formed as a s e q u e n t a i l r e a c t i o n p r o d u c t . +

E f f e c t o f H /C0 R a t i o T h r e e d i f f e r e n t H / C 0 r a t i o ( 1 / 2 , 1/1, and 2/1) w e r e employed i n t h i s s t u d y . The d e t a i l e d r e s u l t s a r e l i s t e d i n T a b l e V I I . As shown i n F i g u r e 4, t h e CO c o n v e r s i o n i n c r e a s e d ( f r o m 20 t o 78%) w i t h i n c r e a s i n g H /C0 r a t i o . Since CO c o n v e r s i o n i s s t o i c h i o m e t r i c a l l y l i m i t e d b y t h e amount o f hydrogen a v a i l a b l e i n t h e feed i n view o f t h e absence o f watergas s h i f t r e a c t i o n , t h e l o w e r t h e H /C0 r a t i o , t h e l o w e r t h e maximum a t t a i n a b l e CO c o n v e r s i o n . F o r e x a m p l e , w i t h t h e H /C0 r a t i o o f 1/2, t h e maximum a t t a i n a b l e CO c o n v e r s i o n , b a s e d o n t h e s t o i c h i o m e t r y o f syngas c o n v e r s i o n over ruthenium c a t a l y s t s o f 2 H / 1 C 0 ( E q u a t i o n I ) , w o u l d b e 25%. T h e r e f o r e , t h e 20% apparent CO c o n v e r s i o n a t t h e H /C0 r a t i o o f 1/2 r e f l e c t e d 8 0 % o f t h e maximum a t t a i n a b l e CO c o n v e r s i o n . I n t h e r a n g e o f H /C0 r a t i o employed h e r e , t h e p o s s i b l e CO c o n v e r s i o n was a l l h i g h , a m o u n t i n g t o a b o u t 8 0 % o f t h e maximum a t t a i n a b l e CO c o n v e r s i o n , a s r e p r e s e n t e d b y t h e d o t t e d l i n e i n F i g u r e 4. ?

2

2

9

2

2

2

2



Figure 1.

Effect of pressure on syngas conversion over 5% Ru(as (294°C, GHSV = 480, and H J CO = 2/1)

Ru0 )/ZSM-5


2

316

CATALYTIC

ACTIVATION

OF CARBON

MONOXIDE

Table V

EFFECT OF TEMPERATURE ON SYNGAS CONVERSION OVER 5% Ru (AS R u 0 ) / 2

ZSM-5 AT 51 a t m , GHSV = 4 8 0 , AND H /C0 = 2/1. 2

Temp., °C

264

294

328

CO

93

86

78

H

98

96

97

40.0

35.5

35.8

H,

0.2

0.5

0.4

CO

6.3


Conversion, wt%

2

T o t a l Product, wt% Hydrocarbon

co

1.0

2

H 0 Hydrocarbon Composition, wt%

11.8 3.6

18.9 4.5

52.6

48.6

40.0

10.3

26.0

61.3

1.0

4.3

6.5

-

-

-

1.2

5.1

4.5

V

0.1

0.7

-

i-c

1.9

5.6

5.3

4.2

4.5

3.4

0.2

0.9

-

3.1

5.4

3.9

4.7

3.5

1.4

65/8

29.5

8.2

7.7

14.7

8.2

81.3

53.1

19.1

9.4

27.7

43.1

99.2

97.4

95.8

2

C

l

V V C

3°

n-C

4

4

V i-c

5

n-C C^

non-aromatics

Aromatics +

C i n T o t a l H.C., w t %

+ A r o m a t i c s i n C^ , w t % Hydrocarbon S e l e c t i v i t y ,

%

B r o m i n e No. o f L i q . P r o d u c t

90


H U A N G AND HAAG

Aromatic

Gasoline

Όsing

317

Ru/Zeolites


20.

Figure 2.

Effect of Temperature on syngas conversion over 5% Ru(as ZSM-5 (294°C, GHSV = 480, and HJCO = 2/1)


Ru0 )/ 2

318

CATALYTIC ACTIVATION OF CARBON MONOXIDE

Table V I EFFECT OF SPACE VELOCITY ON SYNGAS CONVERSION OVER 5% Ru(AS Ru0 > 2

ZSM-5 AT 294°C, 75 atm, AND H /CO = 2 / 1 . 2

GHSV

180

480

1428

CO

91

90

93

H,

98

98

98

37.0

37.4

34.9

H,

0.2

0.2

0.2

CO

7.6

8.8

5.8

9.2

3.8

0.9

46.0

49.8

58.1

34.4

26.1

13.4

5.1

3.4

1.6

2=

-

-

-

V

5.0

3.0

1.8

0.1

0.2

0.1

5.9

3.5

1.8

4.1

3.6

2.6

-

-

0.1


Conversion, wt%

T o t a l P r o d u c t , wt% Hydrocarbon

co

2

H0 2

Hydrocarbon Composition, wt% l

C

V C

C

3=

n-C C

4

4-

i-c

5

4.6

4.1

3.0

n-C

5

3.3

4.0

3.7

23.7

40.8

58.7

14.0

11.5

13.3

45.6

60.4

78.7

30.7

19.1

16.9

92.7

97.0

99.3

C^

non-aromatics

Aromatics C

5

+

i n T o t a l H . C . , wt%

+ Aromatics i n C^ , wt% Hydrocarbon S e l e c t i v i t y , wt%


HUANG

AND HAAG

Aromatic

Gasoline

Using

319

Ru/Zeolites


20.

Figure 3.

Effect of space velocity on syngas conversion over 5% ZSM-5 (294°C, 75 aim, and H CO = 2/1)

Ru(as

2


Ru0 )/ 2

320

CATALYTIC ACTIVATION OF

CARBON

MONOXIDE

Table V I I EFFECT OF H /C0 RATIO ON SYNGAS CONVERSION OVER 5% Ru (AS R u 0 > / 2

2

ZSM-5 AT 294°C, 27 a t m , AND GHSV = 4 8 0 . H /CO, m o l e r a t i o

1/2

1/1

2/1

CO

20

38

78

H

74

85

92

10.9

19.5

35.2

0.9

1.0

1.4

77.7

58.3

20.8

2.4

3.6

3.1

8.3

17.6

39.5

17.7

24.4

44.5

3.3

2.6

5.0

-

-

2

Conversion, wt%

2


T o t a l P r o d u c t , wt% Hydrocarbon H

2

CO

co

2

H 0 2

Hydrocarbon C

Composition, wt%

l

V

-

V

15.7 1.5

n-C. 4

V i-c n-C

-

-

20.5

19.9

10.5

10.5

10.1

6.1

-

-

5

8.9

9.9

6.1

5

2.8

1.4

2.3

1.2

3.5

7.8

18.1

15.8

10.6

30.9

30.6

26.8

58.4

51.5

39.4

92

93.5

86.3

C^ non-aromatics Aromatics +

7.1

-

+

C

12.4

i n T o t a l H.C.,

wt%

+ A r o m a t i c s i n C^ , w t % Hydrocarbon S e l e c t i v i t y , O c t a n e No. (R+O) o f L i q u i d Product B o i l i n g Range o f C * 90% O v e r h e a d

%

104

102

94

212

201

182

°C


Aromatic

H U A N G AND HAAG

Gasoline

Using

Ru/Zeolites

321


20.

Figure 4.

Effect of H /CO ratio on syngas conversion over 5% ZSM-5 (294°C, 27 atm, and GHSV = 480) 2

Ru(as


Ru0 )/ 2

CATALYTIC ACTIVATION

322

O F CARBON

MONOXIDE

The y i e l d was r a t h e r i n s e n s i t i v e ^ t o t h e H^/CO r a t i o i n t h i s range. However, t h e a r o m a t i c s i n C increased sharply with d e c r e a s i n g H /CO r a t i o , r e a c h i n g 9 4 % a t t h e H /CO r a t i o o f 1/2; t h e a r o m a t i c s i n t o t a l h y d r o c a r b o n i n c r e a s e d f r o m 1 1 % a t 2/1 r a t i o t o 1 8 % a t 1/2 r a t i o . More i m p o r t a n t l y , C^+C,^ f o r m a t i o n decreased s h a r p l y w i t h d e c r e a s i n g H /C0 r a t i o . The b o i l i n g range o f was s h i f t e d t o w a r d h i g h e r b o i l i n g p o i n t a s t h e H /CO r a t i o was d e c r e a s e d , a l t h o u g h more a r o m a t i c s a n d l e s s methane w e r e p r o d u c e d w^.th l o w e r Hp/CO r a t i o . Furthermore, t h e o c t a n e number o f t h e C,. f r a c t i o n i n c r e a s e d w i t h d e c r e a s i n g H /CO r a t i o a s shown b e l o w i n agreement w i t h t h e h i g h e r a r o m a t i c s content. fi

2

2

2

2


2

H /CO R a t i o

1/2

1/1

2/1

O c t a n e No. (R+0)

104

102

94

2

Conclusion The i n c o r p o r a t i o n o f a ZSM-5 c l a s s z e o l i t e i n t o a r u t h e n i u m F i s c h e r - T r o p s c h c a t a l y s t promotes a r o m a t i c s f o r m a t i o n and reduces the molecular weight o f the hydrocarbons produced. These composite c a t a l y s t s can produce a h i g h octane aromatic g a s o l i n e i n good y i e l d i n a s i n g l e s t e p d i r e c t l y f r o m s y n t h e s i s g a s . The s t u d y o f t h e e f f e c t s o f p r o c e s s p a r a m e t e r s r e v e a l s t h a t (1) methane c a n b e s u b s t a n t i a l l y r e d u c e d b y h i g h e r p r e s s u r e , s h o r t e r c o n t a c t t i m e , l o w e r t e m p e r a t u r e , and l o w e r H^/CO r a t i o ; and (2) t h e a r o m a t i c s p r o d u c t i o n i s g r e a t l y f a v o r e d b y l o w e r H /C0 r a t i o a t moderate temperature. 2

Abstract Ruthenium is known to be a good catalyst for producing high molecular weight paraffin wax from H / C O at high pressure and low temperature, or making methane at low pressure and moderate temperature. However, the present study reveals that aromatic gasoline of high quality with good y i e l d can be produced directly from synthesis gas under proper conditions in the presence of dual-functional ruthenium-containing ZSM-5 class zeolite catalysts. The nature of the product depends upon the dual-functionality of the catalyst system. The effects of method of catalyst preparation and ruthenium loading, as well as process variables such as temperature, pressure, space velocity and H /CO ratio on the product distribution are discussed. 2

2

Acknowledgement We w i s h t o t h a n k Mr. C. L . T a t s c h a n d M r . R. M. W a l l a c e their excellent technical assistance.


for

20.

H U A N G AND HAAG


Literature

Aromatic

Gasoline

Using

Ru/Zeolites

323

Cited

1. Chang, C. D.; Lang, W. H.; Silvestri, A. J. J. Catal., 1979, 56, 268. 2. Caesar, P. D.; Brennan, J. Α.; Garwood, W. E.; Ciric, J. J. Catal., 1979, 56, 274. 3. Meisel, S. L.; McCullough, J. P.; Lechthaler, C. H.: Weisz, P. B. Chemtech 1976, 6, 86. 4. Chang, C. D.; Silvestri, A. J. J. Catal., 1977, 47,249. 5. Storch, H. H.; Golumbic, N.; Anderson, R. B. "The FischerTropsch and Related Syntheses", Wiley, New York, 1951, p. 309. 6. Pichler, H. Adv. Cat., Vol. IV, 1952, 271. 7. Karn, F. S.; Schultz, J. F.; Anderson, R. Β. I & Ε C Product Research and Development, 1956, 4, 265. 8. Ekerdt, J. G.; Bell, A. T. J. Catal, 1979, 58, 170. 9. Ollis, D. F.; Vannice, M. A. J. Catal., 1975, 37, 449. 10. King, D. L. J. Catal., 1978, 51, 386. 11. Everson, R. C.; Woodburn, E. T.; Kirk, A. R. J. Catal., 1978, 53, 186. 12. Dalla Betta, R. Α.; Shelef, M. J. Catal., 1977, 49, 383. 13. Jacobs, P. Α.; Nijs, H. H.; Verdonck, J. J.; Uytterhoven, J. B. Preprint. Petroleum Chem. Div., Am. Chem. Soc., March 12-17, 1978, p. 469. 14. Meisel, S. L.; McCullough, J. P.; Lechthaler, C. H.; Weisz, P. B. Leo Friend Symposium, Am. Chem. Soc., Chicago, Illinois, Aug. 30, 1977. 15. Weisz, P. B. Adv. Catal., 1962, 13, 137. 16. Huang, T. J.; Haag, W. O. Unpublished data. RECEIVED December 8, 1980.


Carbon Monoxide Over Ruthenium

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