Mass Transfer and Product Selectivity in a Mechanically Stirred

19 Mass Transfer and Product Selectivity in a Mechanically Stirred Fischer-Tropsch Slurry Reactor

Downloaded by UNIV OF PITTSBURGH on July 13, 2013 | http://pubs.acs.org Publication Date: September 16, 1982 | doi: 10.1021/bk-1982-0196.ch019

CHARLES N . SATTERFIELD and G E O R G E A . HUFF, JR. Massachusetts Institute of Technology, Department of Chemical Engineering, Cambridge, M A 01239 With a reduced fused magnetite c a t a l y s t a sub s t a n t i a l g a s - t o - l i q u i d mass t r a n s f e r r e s i s t a n c e can be encountered, which causes the p a r a f f i n - t o -olefin r a t i o of the hydrocarbon products to decrease. Under intrinsic k i n e t i c c o n d i t i o n s t h i s r a t i o in creases w i t h hydrogen c o n c e n t r a t i o n in the l i q u i d but i s independent of carbon monoxide c o n c e n t r a tion. Hence with s i g n i f i c a n t m a s s - t r a n s f e r , t h i s ratio i s governed by the r e s i s t a n c e to H t r a n s f e r r a t h e r than by the e f f e c t i v e H /CO r a t i o in the liquid. 2

2

With a f i n e l y d i v i d e d s o l i d c a t a l y s t as t y p i c a l l y used i n the Fischer-Tropsch s y n t h e s i s i n s l u r r y r e a c t o r s i t i s g e n e r a l l y agreed that the major mass-transfer r e s i s t a n c e , i f i t occurs, does so a t the g a s - l i q u i d i n t e r f a c e . There a r e c o n s i d e r a b l e disagreements about the magnitude o f t h i s r e s i s t a n c e that stem from u n c e r t a i n t i e s about c e r t a i n p h y s i c a l parameters, notably i n t e r f a c i a l area, but a l s o the s o l u b i l i t y and mass t r a n s f e r coeff i c i e n t s f o r H and CO that apply to t h i s system. However when t h i s r e s i s t a n c e i s s i g n i f i c a n t , the concentrations o f ^ and CO i n the l i q u i d i n contact with the s o l i d c a t a l y s t become l e s s than they would be otherwise, which not only reduces the observed r a t e of r e a c t i o n but can a l s o a f f e c t the product s e l e c t i v i t y and the r a t e of formation o f f r e e carbon. 2

Experimental Studies were c a r r i e d out i n a o n e - l i t e r , m e c h a n i c a l l y - s t i r r e d autoclave operated i n a semi-continuous f a s h i o n i n that the c a t a l y s t and l i q u i d c a r r i e r (normal-octacosane) remain i n the r e a c t o r whereas s y n t h e s i s gas i s sparged to the r e a c t o r and v o l a t i l e products removed overhead. The phases are w e l l mixed, which simp l i f i e s i n t e r p r e t a t i o n o f experimental r e s u l t s . Moreover, the degree o f mass t r a n s p o r t can be c o n t r o l l e d by v a r y i n g the degree 0097-6156/82/0196-0225$06.00/0 © 1982 American Chemical Society In Chemical Reaction Engineering—Boston; Wei, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1982.


226

CHEMICAL REACTION ENGINEERING

of a g i t a t i o n , s i n c e g a s - l i q u i d i n t e r f a c i a l area i n c r e a s e s w i t h power i n p u t . The autoclave has a diameter of 7.6 cm with two b a f f l e bars (0.75-cm wide) that are spaced 180° a p a r t . I t i s a g i t a t e d w i t h a 5.08-cm diameter p r o p e l l e r (3 blades at a 45° p i t c h ) s e t above a s i x f l a t - b l a d e d d i s k (each 1.27-cm square) t u r b i n e i m p e l l e r 5.08 cm i n diameter. The i m p e l l e r i s 3.5 cm above the w i d e - c o n i c a l bottom of the r e a c t o r . Gas i s f e d through a 0.32-cm i . d . h o l e i n the center of the bottom. E i t h e r a hollow or s o l i d s h a f t s t i r r e r can be employed. The hollow s h a f t a g i t a t o r i n c r e a s e s gas r e c i r c u l a t i o n from top to bottom and the f a c t that we found no d i f f e r e n c e i n our r e s u l t s between the two types i s a d d i t i o n a l evidence that the system behaves as a CSTR. F u r ther d e t a i l s o f the apparatus and a n a l y t i c a l procedures are a v a i l a b l e elsewhere (1, 2 ) . The c a t a l y s t was a reduced fused magnetite, type C-73, from United C a t a l y s t s , Inc. and normally employed f o r ammonia synthesis. I t contained 2-3% A 1 0 , 0.5-0.8% K 0, 0.7-1.2% CaO and 99% p u r i t y ) to produce a 15 weight-percent suspension, based on unreduced c a t a l y s t weight. Cold s t u d i e s i n a transparent mockup i n d i c a t e d that t h i s f i n e l y d i v i d e d c a t a l y s t d i d not s e t t l e on the r e a c t o r bottom at s t i r r i n g speeds o f 200 RPM o r g r e a t e r . Two runs are r e p o r t e d on here, each of which encompassed s e v e r a l hundred hours d u r i n g which a v a r i e t y o f c o n d i t i o n s were s t u d i e d . A separate c a t a l y s t batch was used f o r each of the two. 2

3

2

2

Catalytic Activity F i g u r e 1 d e p i c t s the e f f e c t of changing the s t i r r i n g speed on the conversion of hydrogen p l u s carbon monoxide at each o f three temperatures. Two d i s t i n c t r e g i o n s appear i n the curves w i t h a t r a n s i t i o n a l zone a t about 400 RPM. In a l l cases, convers i o n becomes independent of a g i t a t i o n and s t r o n g l y dependent on temperature at the h i g h e r degrees of a g i t a t i o n . As expected from theory, a f a s t e r s t i r r i n g speed i s r e q u i r e d to move out of the g a s - l i q u i d c o n t r o l l i n g r e g i o n at 263 C than 232°C. e

Intrinsic Kinetics D e t a i l e d i n f o r m a t i o n on the i n t r i n s i c k i n e t i c e x p r e s s i o n f o r t h i s c a t a l y s t w i l l be a v a i l a b l e elsewhere ( 3 ) . The water-gass h i f t r e a c t i o n proceeds e s s e n t i a l l y to e q u i l i b r i u m (and hence completion) under our c o n d i t i o n s , and based on the observed p r o duct composition, the s t o i c h i o m e t r y f o r the r e a c t i o n becomes : 6 CO + 7/2 H

2

C H 3

?

+ 3 C0

2

In Chemical Reaction Engineering—Boston; Wei, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1982.

(1)


SATTERFIELD AND HUFF

Figure 1.

Fischer-Tropsch Slurry Reactor

Effect of stirring speed on synthesis gas conversion. Conditions: 790 kPa, 150 L gas (STP)/L liquid-hr and (H /CO) ed = 0.69. t

t

fe



228

The i n t r i n s i c data were w e l l c o r r e l a t e d by a Langmuir-Hinshelwood type o f expression which f o r the c o n d i t i o n s here, reduces to an expression zero order i n CO and f i r s t order i n H : 2

""

"VCO

1 9 / ?

S

=

-

1 9 / 1 2 R

k

C

( 2 )

C 0 " H,L

Although water vapor exerts an i n h i b i t i n g e f f e c t on the r a t e (4), i t s c o n c e n t r a t i o n here was so low, because o f the low H /CO r a t i o s used and the occurrence o f the w a t e r - g a s - s h i f t r e a c t i o n , that i t s i n f l u e n c e can be ignored. Equation (2) can be r e - w r i t ten i n terms o f p a r t i a l pressure o f H by a p p l y i n g Henry's law, 2


2

P

H

" "H !.,!, 0

5

-*H CO 2+

( k /

*H

) P

3

H

In the analyses that f o l l o w , i t i s f u r t h e r assumed that the hydrogen t o carbon monoxide usage r a t i o i s independent o f convers i o n and given by a value o f 7/12· Mass T r a n s f e r Since the i n t r i n s i c r a t e i s independent o f carbon monoxide c o n c e n t r a t i o n , we need consider only the mass t r a n s f e r o f hydrogen across the g a s - l i q u i d i n t e r f a c e from the standpoint o f a c t i vity. However both r e a c t a n t m a t e r i a l balances need t o be cons i d e r e d i n the more general case s i n c e the true c o n c e n t r a t i o n o f carbon monoxide a t the c a t a l y s t s u r f a c e may a l t e r s e l e c t i v i t y :

The concentrations o f hydrogen and carbon monoxide i n the l i q u i d are given upon rearrangement of equations (4) and (5), r e s p e c t i v e l y , as:

7d-e )(-V G

4 C 0

)

"C Equations

(6) and (4) can be combined t o e l i m i n a t e C„ _ a s :


19.


P

HH

7 ( 1


£

- G

)

1I

+

mass t r a n s f e r

1f -

=

intrinsic

where an o v e r a l l apparent r a t e constant k

Q

229

(8)

observed

i s d e f i n e d by:

"VCO - VV H P

(

( 9 )

From equation (8) values o f the mass t r a n s f e r component κ k^ a/(l-ε^) can be estimated from measured v a l u e s o f -RJJ * under mass t r a n s f e r - l i m i t e d c o n d i t i o n s by u s i n g 2 values o f k determined from i n t r i n s i c k i n e t i c s t u d i e s . The a c t u a l c o n c e n t r a t i o n s o f hydrogen and carbon monoxide i n the l i q u i d can then be c a l c u l a t e d from equations (4) and ( 5 ) , respec t i v e l y . Values o f k , the apparent r a t e constant, c a l c u l a t e d by equation (9) f o r the same experimental runs d e p i c t e d i n F i g u r e 1, d i v i d e d by hydrogen s o l u b i l i t y , are p l o t t e d on a l o g a r i t h m i c s c a l e a g a i n s t r e c i p r o c a l temperature i n F i g u r e 2. The l i n e a r c o r r e l a t i o n a t the h i g h e s t s t i r r i n g speed w i t h an a c t i v a t i o n energy of 100 kJ/mol i s f u r t h e r i n d i c a t i o n that these data are i n t r i n s i c and u n a f f e c t e d by mass t r a n s f e r . The data a t constant, lower, s t i r r i n g speeds e x h i b i t the c l a s s i c a l shapes expected by a r e a c t i o n that becomes i n c r e a s i n g l y c o n t r o l l e d by mass t r a n s f e r . The dashed l i n e s i n F i g u r e 2 a r e t h e o r e t i c a l curves p r e d i c t e d by equation ( 8 ) , based on the average mass t r a n s f e r term κ backc a l c u l a t e d a t each temperature and same s t i r r i n g speed. P h y s i c a l t r a n s p o r t appears t o be r e l a t i v e l y independent o f temperature and conversion even though i t i n c r e a s e s markedly w i t h s t i r r i n g speed. Increased gas c o n t r a c t i o n (and hence lower s u p e r f i c i a l v e l o c i t y ) a s s o c i a t e d w i t h the higher conversions a t higher temp eratures a f f e c t s both gas hold-up and i n t e r f a c i a l area a i n g a s - l i q u i d systems w i t h mechanical a g i t a t i o n ( 5 ) . However, the data o f Westerterp,et a l . ( 6 ) i n d i c a t e that a / ( l - e ) i s i n s e n s i t i v e to gas-flow rape. Values of κ are p l o t t e d i n F i g u r e 3 f o r two runs, one u s i n g a s o l i d - s h a f t s t i r r e r and a second u s i n g a h o l l o w - s h a f t a g i t a t o r . Within the s c a t t e r o f the data, there appears t o be no d i f f e r e n c e between the two runs, i n d i c a t i n g that the contents are indeed w e l l mixed, even a t lower s t i r r i n g speeds. The component κ v a r i e s w i t h s t i r r i n g speed t o the 4 ±1 power i n our combined p r o p e l l e r / i m p e l l e r aerated mixer over the range o f a g i t a t i o n used.


β

+ c 0

G

K

C

a n (

C

r

0

m

e

u

a

t

i

o

n

s

To estimate the values o f * *C L ^ 9 above, s o l u b i l i t i e s and mass t r a n s f e r * c o e f f i c i e n t s need to be known. The mass t r a n s f e r c o e f f i c i e n t f o r carbon monoxide was measured by Deckwer, e t a l . (7) t o be 0.010 cm/s and v e r i f i e d by them w i t h Calderbank and Moo-Young's (8) small-bubble c o r r e l a t i o n , using d i f f u s i v i t i e s estimated from a r e l a t i o n proposed by Sovova (9). From these expressions, the dependence o f the mass t r a n s f e r H

L


230


5.0 Κ 0.40 s ^ .Εα =100 K J /mol Μς. 0.10 s >>Χ 8

1

1

K 1

X.0.037S

X

^ 1


]V 0.020s . Ο X

\ NN

^> . ~ N V

/ multiple χ

1.0

Ai 0.5

l 180

263*C

1.85

232*èvl

248C

t

t

t

1.90 1000/T/K

1.95

2.00

1

Figure 2. Observed rate constant for the same data points and conditions as in Figure 1. Key: +, 600 rpm; ψ , 400 rpm; · , 300 rpm; | , 250 rpm; and A, 200 rpm.

100 200 300 400 500 STIRRING SPEED,N, RPM Figure 3. Effect of stirring speed on mass transfer resistance, κ. Key: , solid shaft stirrer and the same data points as in Figure 1; and · , hollow shaft stirrer, 248-263°C, 400-1140 kPa, and (H /CO) = 0.34-0.62. t

feea


19.


231


c o e f f i c i e n t on molar volume V can be deduced from which the mass t r a n s f e r c o e f f i c i e n t f o r hydrogen can be c a l c u l a t e d a s : g

VH • h,C B,C B,/* (V

/V

4

10)

~

5

CONCENTRATION,

liq.

Figure 4. Propane to propylene ratio in intrinsic and mass transfer-limited regions at 248°C. Key: i * , Run 1, HJCO feed = 0.55-1.8, 400-790 kPa, and 60-180L gas/L liquid-hr (intrinsic); · , Run 2, HJCO feed = 0.34-0.62, 280-1140 kPa, and 100L gas/L liquid-hr (intrinsic); A, Run 2, H /CO feed = 0.62, 1.1 MPa, and 100L gas/L liquid-hr (mass transfer); and ψ , Run 2, HJCO feed = 0.34, 1.1 MPa, and 100L gas/L liquid-hr. t

hi Ζ

Ο Σ

Ο

0.5x10' C

H L %

5

HYDROGEN

1.0x10 LIQUID mol / c m

Figure 5.

5

PHASE 3

1.5x10"

5

20x1Ô

5

CONCENTRATION,

liq.

Heptane to heptene ratio in intrinsic and mass transfer-limited regions at 248°C. Key is the same as in Figure 4.


19.


233


the gas present. Thus one must be c a r e f u l t o separate the e f f e c t upon the H and CO c o n c e n t r a t i o n s i n the l i q u i d caused by change i n conversion from that caused by mass t r a n s f e r . In the f i r s t s e t o f runs i n Table I , the H /CO feed r a t i o exceeds the consumption r a t i o , 7/12 * 0.58; i n the second i t i s l e s s than the consumption r a t i o . In each case, the H p a r t i a l pressure i n the r e a c t o r i n c r e a s e d with decreased a g i t a t i o n , as conversion dropped. In the absence o f mass t r a n s f e r r e s i s t a n c e t h i s would be expected to i n c r e a s e the P / 0 r a t i o . The f a c t that the P / 0 r a t i o i n both cases i n s t e a d decreased i s c o n s i s t e n t w i t h the p o s t u l a t e that the H c o n c e n t r a t i o n i n the l i q u i d has decreased. The corresponding mass t r a n s f e r r e s i s t a n c e κ , backc a l c u l a t e d from equation ( 8 ) , i s g i v e n a t each s t i r r i n g speed together with the hydrogen and carbon monoxide l i q u i d - p h a s e con c e n t r a t i o n s that a r e estimated by equations (6) and ( 7 ) . 2

2

2


2

The H / C 0 feed r a t i o s used here were chosen t o be u n u s u a l l y low, so t h a t the hydrogen l i q u i d phase c o n c e n t r a t i o n s would be low, where s e l e c t i v i t y e f f e c t s caused by mass t r a n s f e r should be more n o t i c e a b l e . I n g e n e r a l , however, c o n s i d e r a b l y higher H2/CO feed r a t i o s a r e u s u a l l y used t o minimize carbon formation so the feed r a t i o o f H / C 0 g e n e r a l l y exceeds the usage r a t i o . Hence under mass-transfer l i m i t e d c o n d i t i o n s the r e a c t i o n becomes p a r t i c u l a r l y s t a r v e d f o r carbon monoxide s i n c e i t i s t r a n s p o r t e d more slowly than hydrogen (k. k_ /1.4) and i t i s the s t o i chiometrically-limiting reactant. * The p a r a f f i n t o o l e f i n r a t i o s taken i n a mass-transfer l i m i t i n g environment a r e a l s o p l o t t e d i n F i g u r e s 4 and 5 a g a i n s t p r e d i c t e d hydrogen l i q q i d - p h a s e c o n c e n t r a t i o n s . While the mass t r a n s f e r r e s u l t s a r e w i t h i n the data s c a t t e r on the f i g u r e s , we appear t o underestimate the l i q u i d - p h a s e c o n c e n t r a t i o n s l i g h t l y . Perhaps t h i s i s due to a s l i g h t p o s i t i v e dependency o f the i n t r i n s i c e x p r e s s i o n (equation 2) on carbon monoxide and not zero order. T h i s would r e s u l t i n a higher b a c k - c a l c u l a t e d v a l u e o f κ (and thus higher l i q u i d - p h a s e hydrogen concentration) as carbon monoxide i s t r a n s p o r t e d slower than hydrogen. T h i s e f f e c t would be magnified by choosing too s m a l l a hydrogen mass t r a n s f e r c o e f ficient. The average product molecular weight i s u n a f f e c t e d by s t i r r i n g speed, as evidenced by the r a t i o o f C^ t o C 5 hydrocarbons i n Table I . T h i s i s n o t s u r p r i s i n g as we have observed w i t h i n t r i n s i c s t u d i e s that t h i s i s r e l a t i v e l y independent o f r e a c t i o n c o n d i t i o n s (15). However, an i n c r e a s e d Η / 0 0 l i q u i d - p h a s e r a t i o due to mass t r a n s f e r l i m i t a t i o n s should decrease f r e e carbon d e p o s i t i o n by the Boudouard r e a c t i o n (16). 2

2

β

r

H

2

Conclusions With an a c t i v e reduced fused magnetite c a t a l y s t i n a s t i r r e d autoclave r e a c t o r we have shown that s u b s t a n t i a l mass t r a n s f e r r e s i s t a n c e s a r e r e a d i l y encountered that can g r e a t l y lower the



R

2

" H +CO

)

7.45 7.12 6.00 5.03 4.20

4.81 4.66 4.20 3.21

600 400 300 200

mol/s-cm^

(

600 400 300 250 200

Stirring Speed, Ν RPM

Table I .

liq.

ρ

7.21 7.24 7.41 7.61

4.08 4.25 5.05 5.34 5.69

C,atm

1.72 1.72 1.88 2.13

2

(H /C0)

2.98 2.97 3.41 3.55 3.71

2

(H /C0)

H,atm

3=

.139 .136 .131 .130

feed

.182 .176 .169 .161 .148

feed

3

C

C

.199 .198 .197 .194

0.34

.268 • 258 .258 .241 .237

0.62

7

7

n-C =

n-C 5

l

4.10 3.82 4.21 3.73

5.13 5.72 5.56 6.62 5.31

C

C

.63 .083 .025

—

.44 .045 .025 .016

s

-1

κ m

7.21 7.13 6.65 5.70

4.08 4.00 3.06 2.35 1.79

atm

C

c C,L

E f f e c t o f Mass T r a n s f e r on S e l e c t i v i t y a t 248°C and 1.1 MPa.


1.72 1.67 1.50 1.16

2.98 2.85 2.41 2.04 1.74

atm

C

\ H,L

-Ρ»

19.


235


observed r e a c t i o n r a t e below that otherwise a t t a i n a b l e . Under i n t r i n s i c r e a c t i o n c o n d i t i o n s the p a r a f f i n to o l e f i n r a t i o o f the hydrocarbon products i n c r e a s e s w i t h hydrogen c o n c e n t r a t i o n and i s independent o f CO c o n c e n t r a t i o n . Under m a s s - t r a n s f e r l i m i t i n g c o n d i t i o n s t h i s P/0 r a t i o dropped, i n accordance w i t h theory. Although the g r a d i e n t f o r hydrogen t r a n s f e r i s l e s s than the g r a d i e n t f o r CO t r a n s f e r , i t i s the hydrogen l i q u i d - p h a s e con c e n t r a t i o n that governs t h i s s e l e c t i v i t y and not the H /CO r a t i o as such, as has been assumed i n some previous a n a l y s e s . T h i s i s because o f the form o f the k i n e t i c e x p r e s s i o n that governs p a r a f f i n - o l e f i n s e l e c t i v i t y on t h i s c a t a l y s t . Under i n t r i n s i c - k i n e t i c c o n d i t i o n s the carbon number d i s t r i b u t i o n o f products from a reduced fused magnetite c a t a l y s t i s n o t s i g n i f i c a n t l y a f f e c t e d by wide v a r i a t i o n s i n and CO concentra t i o n and mass-transfer r e s i s t a n c e s have no n o t i c e a b l e e f f e c t , as would be expected. To the extent that o t h e r s e l e c t i v i t i e s , such as oxygenate product composition, are governed by H and CO con c e n t r a t i o n s i n the l i q u i d , we would s i m i l a r l y expect t o observe e f f e c t s caused by mass t r a n s f e r , although t h i s was n o t done here. Likewise w i t h other c a t a l y s t s , such as c o b a l t , which appear t o be more s e n s i t i v e t o r e a c t i o n c o n d i t i o n s and t o secondary r e a c t i o n s , more marked e f f e c t s from s i g n i f i c a n t mass t r a n s f e r r e a c t i o n s a r e anticipated.


2

2

Legend o f Symbols a C

L

k^

i n t e r f a c i a l area o f gas bubbles, cm^ bubble s u r f a c e area/cm^ expanded! l i q u i d c o n c e n t r a t i o n i n l i q u i d phase, mol/cm^ l i q u i d ; C£ f o r concen t r a t i o n a t e q u i l i b r i u m w i t h the gas, mol/cm^ l i q u i d l i q u i d f i l m mass t r a n s f e r c o e f f i c i e n t , cm^ l i q u i d / c m ^ bubble surface a r e a - s i n t r i n s i c r e a c t i o n r a t e constant, s o v e r a l l apparent r a t e constant, s s o l u b i l i t y c o e f f i c i e n t , cm liquid-atm/mol s t i r r e r speed, RPM p a r t i a l p r e s s u r e , atm r a t e o f r e a c t i o n per u n i t volume o f s l u r r y , mol/cm l i q u i d -s a b s o l u t e temperature, K molar volume o f gas, cm^/mol y

k k m Ν Ρ -R Τ V 0

B

6ç κ

e

gas hold-up. cm^ gas/cm"* expanded l i q u i d ; l-tç f o r l i q u i d hold-up, cwy l i q u i d / c m expanded l i q u i d κ « k ^ a / ( l - e ) , s" H

G

Subscripts C carbon monoxide H hydrogen



236 Acknowledgement

T h i s study was supported by the U.S. Department o f Energy under Contract DE-FG22-81PC40771. Literature Cited 1.


2. 3. 4. 5. 6. 7. 8. 9. 10.

11. 12. 13. 14. 15. 16.

Huff, G. Α., Jr.; Satterfield, C. N. Ind. Eng. Chem., Fun dam. submitted. Huff, G. Α., Jr.; Satterfield, C. N.; Wolf, M. H. Ind. Eng. Chem., Fundam. submitted. S a t t e r f i e l d , C. N.; Huff, G. Α., Jr. t o be p u b l i s h e d . Dry, M. E . Ind. Eng. Chem., Prod. Res. Dev. 1976, 15, 282. Calderbank, P. H. Trans. I n s t n . Chem. Engrs. 1958, 36, 443. Westerterp, K. R.; Van Dierendonck, L. L.; De Kraa, J. R. Chem. Eng. Sci. 1963, 18, 157. Deckwer, W.-D.; L o u i s i , Y.; Z a i d i , Α.; Ralek, M. Ind. Eng. Chem., Process Pes. Develop. 1980, 19, 699. Calderbank, P. H.; Moo-Young, M. Chem. Eng.Sci.1961, 16, 39. Sovova, H. C o l l e c t . Czech. Chem. Commun. 1976, 41, 3715. S a t t e r f i e l d , C. N. "Mass T r a n s f e r in Heterogeneous C a t a l y s i s " M.I.T. P r e s s : Cambridge, Mass., 1970; p. 16. Reprinted 1981, K r i e g e r P u b l i s h i n g Company. Deckwer, W.-D.; Serpemen, Y.; Ralek, M.; Schmidt, B. Chem. Eng. S c i . 1981, 36, 765. S a t t e r f i e l d , C. N.; Huff, G. Α., Jr. Chem. Eng.Sci.1980, 35, 195. S t e r n , D.; Bell, A. T.; Heinemann, H. Chem. Eng. S c i . submitted. K ö l b e l , H.; Ackermann, P.; Engelhardt, F. Proc. Fourth World P e t r . Congress 1955, S e c t i o n IV, 227. S a t t e r f i e l d , C. N.; H u f f , G. Α., Jr. J. C a t a l . 1982, 73, 187. S a t t e r f i e l d , C. N.; Huff, G. Α., Jr. Can.J.Chem. Eng., i n press (February 1982).

RECEIVED April 27, 1982.


Mass Transfer and Product Selectivity in a Mechanically Stirred

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