Reduction of sulfur dioxide to elemental sulfur
by John D Bryan
A THESIS Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree
of Master of Science in Chemical Engineering
Montana State University
© Copyright by John D Bryan (1957)
Abstract:
The reduction of sulfur dioxide to elemental sulfur was investigated using coal char and methane as
reducing agents. Since high temperatures were required when using coal char, methane was found to be
more favorable as the reducing agent.
The reduction of sulfur dioxide with methane (natural gas) was carried out in a fixed-bed catalytic
reactor containing 400 grams of alumina catalyst.
The possibility of increasing yields by following the sulfur dioxide-methane reaction with a reaction
between the hydrogen sulfide formed and unreacted sulfur dioxide was investigated. The low yields of
sulfur that were obtained indicated that sulfur formed in the first reaction was converted to other
products and that the second reaction was probably inhibited by certain components of the gas mixture.
It was determined that operating without a preheat increased yields slightly and that the reaction
products should be cooled as soon as possible after they have left the catalyst bed.
A temperature gradient was detected throughout the catalyst bed and the influence of this gradient was
found to be quite critical. Best results were obtained when the upper portion of the reaction zone was
operated as low as possible without dropping the lower portion of the zone below 560°C, the optimum
temperature for producing sulfur. It was concluded that with close temperature control, conversions up
to 80 percent might be expected with fresh catalyst.
A mole ratio of 3.6 moles of methane per mole of sulfur dioxide and a feed rate of 8 gram-moles of gas
mixture per hour per 400 grams of catalyst appeared to be optimum conditions.
The catalyst activity was shown to decrease approximately linearly with respect to the hours the
catalyst had been in use. REDUCTIQN OF SULFUR DIOXIDE TO ELEMENTAL SULFUR
f
by
John D. Bryan
A
A THESIS
S u bm itted to th e G rad u ate F a c u lty
in
■ P a rtia l F u lf illm e n t of th e R equirem ents
f o r th e D egree o f
M aster o f S cien ce i n Chem ical E n g in ee rin g
at
MONTANA STATE COLLEGE
A pproved;
Head, M ajor Departnjedt
J u ly , 1957
'"y IlilAill
Ul'/1
'Y//
'U"
KJT
«
-
2
-
TABLE OF CONTENTS
A b s tra c t .............................................................................................................................
Page
3
I n tr o d u c ti o n ......................................................................................................................
4
Equipment D esign and C o n s tr u c tio n ........................................................................
I .
Flow S heet ..................................................................................................
II.
D esign and S p e c if ic a tio n o f Component P a r ts ...........................
C -C -C O
P ro ced u re and M a te r ia ls ............................................................................................
I.
P ro ced u re ..................................................................................................
II.
M a te ria ls ..................................................................................................
10
10
12
D isc u ssio n o f R e s u l t s ....................................................................................................... 13
I.
R eduction o f S u lf u r D ioxide U sing Char
a s th e Reducing A g e n t ..............................................................................13
II.
R eduction o f S u lf u r D ioxide U sing Methane
a s th e R educing A g e n t ..............................................................................14
A. Two R ea c tio n Zones i n S e r i e s ............................................ 14
B. C a ta ly s t Bed P o s itio n and P re h e a t T em perature .
16
C. T em p eratu re..................................................................................... 17
D. Feed R a t e ....................................................................................20
E. Mole R a t i o ....................................................................................21
F . C a ta ly s t A c t i v i t y .......................................................................21
S u m m a r y ..................................................................................................................................23
Acknowledgment ................................................................................................................
2$
B ib lio g ra p h y ........................................................................................................................... 26
A p p e n d ix ..................................................................................................................................27
123690
- 3' ABSTRACT
The re d u c tio n o f s u l f u r d io x id e to e le m e n ta l s u lf u r was in v e s tig a te d
u s in g c o a l c h a r and m ethane a s re d u c in g a g e n ts . S in ce h ig h te m p e ra tu re s
were r e q u ir e d when u s in g c o a l c h a r, methane was found to be more fa v o ra b le
a s th e re d u c in g a g e n t. .
The r e d u c tio n of s u l f u r d io x id e w ith methane ( n a tu r a l g as) was
c a r r ie d out in a fix e d -b e d c a t a l y t i c r e a c t o r c o n ta in in g 4 0 0 ' grams of
alum ina c a t a l y s t .
The p o s s i b i l i t y o f in c r e a s in g y ie ld s by fo llo w in g th e s u l f u r d io x id e m ethane r e a c tio n w ith a' r e a c tio n betw een th e hydrogen s u lf id e form ed.and
u n re a c te d s u l f u r d io x id e was in v e s t i g a t e d . The low y i e l d s o f s u lf u r t h a t
were o b ta in e d in d ic a te d t h a t s u lf u r form ed i n th e f i r s t r e a c tio n was con­
v e r te d to o th e r p ro d u c ts and t h a t th e second r e a c tio n was p ro b a b ly i n ­
h i b i t e d by c e r t a i n components of th e gas m ix tu r e .
I t was d eterm in ed t h a t o p e ra tin g w ith o u t a p re h e a t in c re a s e d y ie ld s
s l i g h t l y and t h a t th e r e a c tio n p ro d u c ts should be co o led a s soon a s p o s­
s i b l e a f t e r th e y have l e f t th e c a t a l y s t bed.
A te m p e ra tu re g r a d ie n t was d e te c te d th ro u g h o u t th e c a t a l y s t bed and
th e in flu e n c e of t h i s g ra d ie n t was found t o be q u ite c r i t i c a l . B est
r e s u l t s were o b ta in e d when th e u p p er p o r tio n o f th e r e a c tio n zone was
o p e ra te d a s low a s p o s s ib le w ith o u t d ro p p in g th e low er p o r tio n o f th e zone
below 560°C, th e optimum te m p e r a tu r e .f o r p ro d u cin g s u l f u r . I t was con­
c lu d ed t h a t w ith c lo s e te m p e ra tu re c o n tr o l, c o n v ersio n s up t o 80 p e rc e n t
m ight be ex p ected w ith f r e s h c a t a l y s t ^ . .
,4 * #
'.
, ; .
A mole r a t i o o f 3 .6 m oles o f m ethane p e r mole o f s u lf u r d io x id e and
a fe e d r a t e o f 8 gram -m oles o f gas m ix tu re p e r h o u r p e r 400 grams o f
c a t a l y s t appeared t o be optimum c o n d itio n s .
The c a t a l y s t a c t i v i t y was shown t o d e c re a se a p p ro x im a te ly l i n e a r l y
w ith r e s p e c t to th e h o u rs th e c a t a l y s t 'h a d been in, u s e .
.
\ ■ '
, W ':,
;
- 4 INTRODUCTION
I n re c e n t y e a rs a g r e a t d e a l o f a p p reh en sio n h a s been f e l t because
o f th e lim it e d amount of s u l f u r a v a il a b le t o th e U nited S t a t e s .
In th e
e a r l y p a r t o f th e 1950' s a s e r io u s s u l f u r sh o rta g e was r e a l i z e d an d -step 's
were ta k e n to overcome t h i s s h o r ta g e .
S in ce th e n , new m ines have been
d is c o v e re d , o ld m ines reo p en ed , and more and more b y -p ro d u c t s u lf u r has
been produced.
At th e p re s e n t tim e th e s u lf u r sh o rta g e i s n o t a s p re s s in g
a s i t was, b u t th e r e i s s t i l l n o t an u n lim ite d su p p ly .
At p r e s e n t th e main so u rc e s of s u lf u r i n th e U n ited S ta te s a r e ;
1.
The F ra sc h p ro c e s s f o r re c o v e rin g s u lf u r
from e le m e n ta l s u l f u r d e p o s its .
2.
P y r ite s which i s i n g e n e r a l a tr a d e name
f o r ir o n s u l f i d e m in e ra ls c o n ta in in g be­
tw een 25 and 50 p e rc e n t s u l f u r .
3.
S u lf a te s w hich, a lth o u g h a la r g e p o t e n t i a l
so u rc e , a r e a c o s tl y s o u rc e .
4.
B y-product s u l f u r .
Most e x p e r ts seem t o a g re e t h a t th e F rasch p ro c e ss i s ab o u t a s w e ll
developed a s i t w i l l e v er b e , so u n le s s new s u lf u r d e p o s its a re found, no
in c r e a s e i n th e s u l f u r p ro d u c tio n can be o b ta in e d th e r e .
q u a n t i t i e s , h a s th e d i s - .
ad v an tag e o f h ig h sh ip p in g c o s ts a s compared t o pure s u l f u r .
T h is le a v e s , th e n , a s th e m ost l i k e l y so u rce of a d d i t i o n a l s u lf u r
•A
r e s e r v e s , th e b y -p ro d u c t s u l f u r . The p e tro le u m in d u s tr y , i n p a r t i c u l a r ,
h a s been p ro d u cin g more and more b y p ro d u ct s u lf u r i n re c e n t y e a r s .
T his
s u l f u r h a s been re c o v e re d from th e hydrogen s u lf id e p r e s e n t i n n a t u r a l
- 5 g a s and r e f i n e r y g a se s by a p p ly in g d i f f e r e n t m o d if ic a tio n s o f th e Glaus
p ro c e ss.
B a s ic a lly , t h i s p ro c e s s in v o lv e s o x id iz in g a p o r tio n of th e
hydrogen s u l f i d e t o s u lf u r d io x id e , and th e n r e a c tin g th e two su b sta n c es
t o g e th e r t o form s u l f u r p lu s w a te r.
A nother la r g e source o f b y -p ro d u ct s u l f u r , p o t e n t i a l l y cap ab le of
pro d u cin g a s much a s th r e e - f o u r t h s o f th e t o t a l s u l f u r re q u ire m e n ts ( 2 ) ,
a r e th e s ta c k g a se s from v a rio u s s m e lte rs i n th e U nited S t a t e s .
/
Those s m e lte rs which a re t r e a t i n g s u lf id e o re s f o r th e re c o v ery
/ o f m e ta ls such a s .c o p p e r , le a d , o r z in c , produce la r g e q u a n t i t i e s of
s u lf u r d io x id e .
The s u lf u r d io x id e i s form ed when th e s u lf id e o re s a re
r o a s te d o r o x id iz e d to c o n v ert th e m e ta l s u l f i d e t o th e m e ta l o x id e .
;
I n t h i s o x id a tio n p ro c e ss th e s u l f u r from th e m e ta l s u lf id e r e a c t s w ith
,
e x cess oxygen to produce s u l f u r d io x id e .
The c o n c e n tra tio n o f s u lf u r
d io x id e i n th e v a rio u s w aste g a se s in a s m e lte r v a r i e s , b u t th e i n t r o !'
\
d u c tio n i n re c e n t y e a r s o f th e F lu o s o lid s r o a s t e r i s s a id t o produce
h ig h e r c o n c e n tra tio n o f s u lf u r d io x id e ( 2 ) .
The f a c t t h a t la rg e - amounts o f s u l f u r a re a v a ila b le i n th e s e sm e lte r
w aste g a s e s , coupled w ith th e f a c t t h a t th e rem oval o f th e s u l f u r from
th e s e g a se s would in c r e a s e th e v a lu e o f th e g ases a s a f u e l and h e lp to
a l l e v i a t e th e problem o f a ir- p o lu tio n , makes th e s e s ta c k g a se s a p p ea r
t o be an a t t r a c t i v e so u rce of s u l f u r .
The f a c t t h a t 70 p e rc e n t o f a l l th e s u l f u r consumed i s u sed i n th e
p ro d u c tio n o f s u l f u r i c a c id ( 5 ) in d i c a t e s t h a t i t m ight be more d e s ir a b le
t o re c o v e r s u lf u r d io x id e from th e s m e lte r g a se s r a th e r th a n e lem en ta l
- 6 -
s u lfu r.
The s u l f u r d io x id e cou ld th e n be c o n v erted t o s u l f u r i c a c id w ith ­
o u t going th ro u g h th e o x id a tio n o f s u l f u r .
However, th e problem o f s to c k ­
p i l i n g and tr a n s p o r t a t i o n make th e p ro d u c tio n o f e le m e n ta l s u lf u r from
th e s m e lte r g a se s a p p ea r a t t r a c t i v e .
The problem r e s o lv e s , th e n , to t h a t
o f c o n v e rtin g th e s u lf u r d io x id e i n th e s m e lte r g a se s to e le m e n ta l s u l f u r .
A rev iew o f p re v io u s work done on th e re d u c tio n o f s u lf u r d io x id e
t o form e le m e n ta l s u l f u r was made by D avis ( 3 ) .
H is su rv ey i l l u s t r a t e s
t h a t coke, n a t u r a l g a s, and carbon monoxide were used a s re d u c tio n a g e n ts ,
and t h a t b a u x ite and vanadium p e n to x id e were employed a s c a t a l y s t s .
In
a d d itio n to th e work review ed by D av is, a sem i-com m ercial u n i t to reduce
s u l f u r d io x id e h a s been o p e ra te d i n G a r f ie ld , Utah (A ).
The p ro c e ss
in v o lv e d b u rn in g n a t u r a l gas w ith a i r c o n ta in in g 5 t o 8 p a r t s by volume
o f s u lf u r d io x id e a t 1250°C.
I t was shown t h a t n a t u r a l gas had t o be
a v a il a b le a t 12 c e n ts p e r th o u san d cu. f t . f o r th e p ro c e s s t o be econ­
o m ic a lly f e a s i b l e .
The re d u c tio n o f s u lf u r d io x id e u s in g hydrogen a t 300°C o v er an i r o n ,
n i c k e l , o r c o b a lt o x id e c a t a l y s t h as been p a te n te d by B osw ell ( I ) .
The l a s t known com m ercial u n it to be in o p e ra tio n was a t a sm e lte r
lo c a te d a t T r a i l , B r i t i s h Colum bia.
T h is u n i t , w ith a c a p a c ity of 150
to n s of s u lf u r p e r day, red u ced th e s u l f u r d io x id e t o s u l f u r o v er a bed
o f in c a n d e s c e n t coke.
The r e s t r i c t i o n t o d a te on p ro c e s s e s in v o lv in g th e re d u c tio n of s u lf u r
d io x id e to e le m e n ta l s u l f u r .h a s b e e n -th e c o s t o f th e re d u c in g a g e n t.
- 7 T h is r e p o r t i s an I n v e s t i g a t i o n of th e p o s s i b i l i t i e s of p roducing
e le m e n ta l s u l f u r from s u l f u r d io x id e .
The u se o f c o a l c h a r , which can
be o b ta in e d ch eap er th a n coke, and n a t u r a l gas a s re d u c in g a g e n ts was
s tu d ie d .
EQUIPMENT DESIGN AND CONSTRUCTION
A.
Flow Sheet
In o rd e r t o i n v e s t i g a t e th e re d u c tio n o f s u l f u r d io x id e u sin g n a tu r a l
g a s a s th e re d u c tio n a g e n t, a fix e d -b e d ,, c a t a l y t i c r e a c t o r was o p e ra te d
a t a tm o sp h eric p r e s s u r e .
A b lo c k flo w diagram o f th e p ro c e s s i s shown
i n F ig . I , and a d e t a i l e d flo w sh ee t o f th e u n it i s shown i n F ig . 2.
F ig u re 2 i l l u s t r a t e s t h a t th e s u l f u r d io x id e and n a t u r a l gas were each
m etered th ro u g h o r i f i c e s and p assed to th e to p o f the- r e a c t o r .
The g a se s
w ere in tro d u c e d to th e m ixing s e c tio n o f th e r e a c t o r , c o n ta in in g alundunr
b a l l s , and th e n p a sse d on down o v er th e c a t a l y s t bed . .The re a c te d g a se s '
from th e c a t a l y s t bed were c a r r ie d t o a c o n s ta n t-te m p e ra tu re condenser
where th e sulfui* was condensed.
The l i q u i d s u l f u r , to g e th e r w ith th e r e ­
m aining g a s e s , p a sse d from th e ' c o n s ta n t-te m p e ra tu re condenser t o th e
bottom o f th e s u l f u r r e c e iv e r where th e s u lf u r s o l i d i f i e d and was c o l l e c t ­
ed i n a cup.
The rem ain in g g ases were c a r r ie d th ro u g h a g la ss -w o o l f i l t e r
t o remove any e n tr a in e d s u lf u r p a r t i c l e s t h a t m ight have rem ain ed , and
th e n p a sse d t o a w a te r-c o o le d condenser where th e w a te r v ap o r was con­
d en sed .
The rem ain in g g a se s were th e n d is c h a rg e d th ro u g h a v e n t l i n e to
th e atm o sp h ere.
- B D u p lic a te equipm ent was p ro v id e d f o r a l l th e u n i t s which were
p o s itio n e d a f t e r th e c o n s ta n t te m p e ra tu re condenser in th e p r o c e s s .
That
I s , two s u lf u r r e c e iv e r s and two w a te r co n d en sers were u sed i n such a
manner t h a t one s e t could be u sed d u rin g th e l i n e - o u t p e r io d , th e n th e
o th e r s e t co u ld be connected i n t o th e p ro c e s s f o r th e a c t u a l ru n .
B.
D esign and S p e c if ic a tio n s o f Component P a r t s '
R e a c to r;
The r e a c t o r , c o n s tr u c te d of 2 -in c h , sch ed u le 40, b la c k -
ir o n p ip e , was 27 i n . in le n g th and was capped a t each end w ith sta n d a rd
c a s t ir o n p ip e c a p s .
The therm o w ell was c o n s tr u c te d o f £ - i n . s ta n d a rd
b la c k - ir o n p ip e , w elded c lo s e d a t th e to p , which p a sse d th ro u g h th e c e n te r
o f th e r e a c t o r .
A s t a i n l e s s - s t e e l sc re e n was p la c e d n e a r th e bottom of
th e r e a c t o r t o a c t a s a su p p o rt f o r th e c a t a l y s t b ed , and a m e ta l b a f f l e
was p la c e d a t th e to p o f th e r e a c to r t o m ix th e incom ing g a se s and p re v e n t
t h e i r im pinging d i r e c t l y on th e to p o f th e th erm o w ell.
D e ta ils o f th e
c o n s tr u c tio n o f th e r e a c t o r a p p ea r in F ig . 3 .
H eat was p ro v id e d t o th e .r e a c to r from th r e e n i chrome c o i l s , each o f
which s u p p lie d h e a t t o a p p ro x im a te ly o n e - th ir d of th e r e a c t o r .
The
r e s i s t a n c e of th e th r e e c o i l s from to p to bottom was 2 4 . 5 , 2 0 , and 24.5
ohms, r e s p e c tiv e ly .
■ The^nichrome c o i l s , s tru n g w ith ceram ic bead's, were wrapped around
th e r e a c t o r o v e r a la y e r o f a s b e s to s t a p e .
The c o i l s were th e n covered
w ith a second la y e r o f a s b e s to s ta p e , and th e r e a c to r was covered w ith a
/
la y e r o f 85 p e rc e n t m agnesia. The to p cap of th e r e a c to r was th e o n ly
p a r t n o t in s u l a t e d .
T his f a c i l i t a t e d more r a p id f i l l i n g and in s p e c tio n
9 o f th e r e a c t o r .
C o n sta n t-te m p e ra tu re C ondenser;
The c o n s tr u c tio n o f th e c o n s ta n t-
te m p e ra tu re condenser i s i l l u s t r a t e d i n F ig . 4 .
The te m p e ra tu re o f th e
con d en ser was a d ju s te d to condense and m a in ta in th e s u lf u r i n a l i q u id
fo rm .
The te m p e ra tu re was c o n tr o lle d by b o i l i n g an e th y le n e g ly c o l-w a te r
m ix tu r e .
The c e n te r tu b e , c o n s tr u c te d o f ^ - i n . t h in - w a ll e l e c t r i c a l c o n d u it,
was 30 i n . in le n g th and was packed w ith ceram ic beads t o g iv e a l a r g e r
h e a t t r a n s f e r a re a f o r th e h o t g a s e s .
The condenser ja c k e t was c o n s tru c te d
o f a 2 6 - in . le n g th o f 1 - i n . d ia m e te r t h in - w a ll e l e c t r i c a l c o n d u it.
Heat
was p ro v id e d t o b o i l the' e th y le n e g ly c o l-w a te r m ix tu re by a n i chrome c o i l
wound around th e lo w er p o r tio n of th e c o n d en ser.
A c o o la n t r e s e r v o i r was
connected t o th e ja c k e t su rro u n d in g th e c e n te r tu b e so t h a t th e b o ilin g
m ix tu re was b e in g c o n s ta n tly c i r c u l a t e d .
'
A w a te r-c o o le d co n d en ser was
f a s te n e d t o th e to p of th e c o p la n t r e s e r v o i r t o condense th e v ap o rs formed
by th e b o ilin g m ix tu re .
S u lf u r R e c e iv e r;
The s u lf u r r e c e iv e r was c o n s tru c te d o f a 1 3 - in .
le n g th o f 2jr:-in. d ia m e te r g la s s tu b in g (See F ig . $ ).
A 9 - i n . le n g th of
1- i n . d ia m e te r g la s s tu b in g extended from th e to p of th e r e c e iv e r to c a r ry
th e g a se s and s u l f u r to th e low er p a r t o f th e r e c e iv e r where a rem ovable
a lu m in u m -fo il cup c o lle c te d th e s u l f u r .
G la ss wool w as'p ack ed between th e
two g la s s tu b e s to a c t a s a f i l t e r f o r any s u lf u r p a r t i c l e s t h a t m ight
have been e n tra in e d i n th e g a s e s .
The to p and bottom o f th e r e c e iv e r were
c lo s e d w ith two la r g e ru b b e r s to p p e r s .
The to p s to p p e r c o n ta in e d a g la s s
— 10 —
tu b e t h a t serv ed a s a g a s ■o u t l e t f o r th e s u lf u r r e c e iv e r .
W ater C ondenser:
The w a te r co n d en ser was c o n s tru c te d from a .3 6 - in .
lo n g w a te r-c o o le d g la s s condenser w ith a 3 / 8 - i n . c e n te r tu b e .
W ater R e c e iv e r:
A o n e - l i t e r E rlenm eyer f l a s k , a tta c h e d to th e bottom
o f th e w a te r c o n d en se r, se rv e d a s a w a ter r e c e iv e r .
Vent L in e:
The v e n t l i n e was J - i n . saran tu b in g .
S u lf u r D ioxide Eeed:
Two sm all s t e e l ta n k s o f ab o u t 3000-gm. capac­
i t y were u sed a s fe e d ta n k s .
S u lfu r D ioxide M ete rin g :
A g la s s v e n tu r i- ty p e o r i f i c e was c a lib r a te d
and u sed i n c o n ju n c tio n w ith a w a t e r - f i l l e d manometer.
N a tu r a l Gas M ete rin g :
A g la s s v e n tu r i- ty p e o r i f i c e was c a li b r a t e d
and u sed in c o n ju n c tio n w ith a B acharach in c lin e d manometer f i l l e d w ith
d ie s e l o i l .
SulfU r D ioxide M etering V alv e:
N a tu ra l Gas M etering V alve:
A u to tra n s fo rm e rs :
Therm ocouples:
Id e a l-A e ro sm ith n e e d le v a lv e .
Hoke b r a s s b lu n t- s p in d le n e e d le v a lv e .
One 2 2 0 -v o lt and th r e e H O -v o lt P o w e rs ta ts .
Three ir o n - c o n s ta n ta n .
Tem perature I n d i c a t o r :
Leeds and N o rth ru p 1 8 -p o in t i n d ic a tin g
p o te n tio m e te r.
PROCEDURE AND MATERIALS
P ro ced u re
R e a c to r Assembly:
The r e a c to r 'Was p la c e d i n p o s itio n and 400 gm. of
c a t a l y s t were poured in to form a s un ifo rm a bed a s p o s s ib le .
s u lte d i n a 1 2 - in . c a t a l y s t b e d .
T his r e ­
Alundum b a l l s were added u n t i l th e
11 r e a c t o r was f u l l , and th e b a f f l e p l a t e was p la c e d in p o s i t i o n .
The to p
cap was th e n screwed o n to ,th e r e a c t o r , fe e d l i n e s were a tta c h e d , th e
th erm ocouples were co n n ected , and th e h e a tin g c o i l le a d s were plugged i n .
The c o n s ta n t-te m p e ra tu re condenser was n e x t connected t o th e r e a c to r
and sec u re d i n p la c e .
C ooling w a te r l i n e s t o th e v a rio u s co n d en sers were
th e n a tta c h e d .
S ta rt-u p s
P o w e rs ta ts f o r th e h e a tin g c o i l s o f th e r e a c t o r were ad­
ju s te d to t h e i r p ro p e r s e t t i n g s and tu rn e d on.
The s u l f u r r e c e iv e r and
w a te r r e c e iv e r to be u sed i n th e run were w eighed, th e w e ig h ts were r e ­
co rd ed , and th e r e c e iv e r s were p la c e d i n p o s i t i o n .
C ooling w a te r to th e
c o n d en sers was tu rn e d on and a l l l i n e s were checked f o r l e a k s .
The r e a c t o r was h e a te d to te m p e ra tu re f o r a t h r e e - t o fo u r-h o u r
p e r io d , th e n th e n a t u r a l gas flo w was s t a r t e d .
A 5 - l i t e r b e a k e r, f i l l e d
w ith h o t w a te r to p re v e n t w a te r from condensing in th e s u l f u r r e c e iv e r was
p la c e d around th e s u l f u r r e c e iv e r and an e l e c t r i c h o t- p l a te was p la ce d
un d er th e b e a k e r to keep th e w ater b o i l i n g .
The c o n s ta n t-te m p e ra tu re
condenser was b ro u g h t t o te m p e ra tu re .
When th e te m p e ra tu re s i n th e r e a c t o r re a ch e d a p o in t ab o u t 20°C below
th e d e s ir e d te m p e ra tu re s , th e s u lf u r d io x id e flo w was s t a r t e d .
I t was
d eterm in ed t h a t th e te m p e ra tu re s i n th e c a t a l y s t bed would r i s e about 20°C
a f t e r th e r e a c tio n s t a r t e d . •
O p e ra tio n :
T em peratures were c o n tr o lle d by a d ju s tin g th e power i n ­
p u t to th e h e a tin g c o i l s w ith th e p o w e rs ta ts .
N a tu ra l gas and s u lf u r .
d io x id e flo w r a t e s were c o n tr o lle d by m a in ta in in g th e d e s ir e d manometer
- 12 re a d in g s f o r each .
I n a d d itio n , th e s u l f u r d io x id e fe e d b o t t l e was
w eighed b e fo re and a f t e r each ru n to check th e amount o f s u l f u r d io x id e
u sed i n each ru n .
Wien th e lin e - o u t p e rio d was co m p leted , th e d u p lic a te
s u l f u r r e c e i v e r , w a te r c o n d en se r, and s u lf u r d io x id e fe e d b o t t l e were
tu rn e d on stream and re a d in g s were re c o rd e d a t 10-m in. i n t e r v a l s u n t i l
th e ru n was com pleted.
Shut-down:
To com plete a run th e s u l f u r d io x id e flo w was sto p p ed ,
and power to th e r e a c t o r c o i l s , c o n s ta n t-te m p e ra tu re co n d en ser c o i l , and
th e h o t-w a te r b a th was tu rn e d o f f .
The n a t u r a l gas was l e f t flo w in g f o r
a s h o rt p e rio d t o f lu s h th e system and th e n tu rn e d o f f .
The s u lf u r
d io x id e ta n k was w eighed and th e amount used d u rin g th e ru n was o b ta in e d
by d if f e r e n c e .
The s u lf u r r e c e iv e r was w eighed and th e amount of s u lf u r
form ed was a ls o o b ta in e d by th e d if f e r e n c e i n w e ig h t.
M a te ria ls
The s u lf u r d io x id e u sed was com m ercial g ra d e , o b ta in e d from th e
M atheson Company o f J o l i e t , I l l i n o i s .
•N a tu ra l gas c o n ta in in g 91 p e rc e n t m ethane, 6 p e rc e n t e th a n e , and 3
p e rc e n t propane was o b ta in e d from th e l i n e s o f th e l o c a l u t i l i t y company.
O n e -e ig h th -in c h e x tru d e d a c ti v a te d alum ina c a t a l y s t m an u factu red by
th e Harshaw Chem ical Company was u sed i n t h i s work.
O n e -fo u rth -in c h alundum b a l l s were u sed a s packing i n th e m ixing
s e c tio n o f th e r e a c t o r .
O n e -fo u rth -in c h ceram ic beads were u sed f o r p ack in g i n th e c o n s ta n tte m p e ra tu re c o n d en se r.
- 13 DISCUSSION OF RESULTS
R e d u c tio n . of S u lf u r D ioxide U sing Char a s th e Reducing A g en t.
In o rd e r t o i n v e s t i g a t e th e fo rm a tio n o f s u lf u r from s u l f u r d io x id e
some work was done u s in g c o a l ch ar a s a re d u c in g a g e n t.
S in ce th e therm o­
dynamics o f s e v e r a l p o s tu la te d r e a c tio n s betw een s u lf u r d io x id e and c o a l
c h a r (carb o n ) to form s u l f u r in d ic a te d th e r e s u l t s could be fa v o ra b le (See
T able I ) , s e v e r a l e x p e rim e n ta l ru n s were made.
The r e a c t o r was charged w ith c o a l c h ar and ru n s were' made u sin g both
s u l f u r d io x id e and a m e th a n e -s u lfu r d io x id e m ix tu re .
An a tte m p t was made
t o make th e ru n s a t 600°C, th e h ig h e s t te m p e ra tu re i t was f e l t th e equip­
ment could w ith s ta n d f o r any extended p e rio d o f tim e .
When th e m ethane-
s u lf u r d io x id e m ix tu re was p a ss e d o v er c h a r a t te m p e ra tu re s between 565°C
and 594°C, no s u l f u r was re c o v e re d .
When o n ly s u lf u r d io x id e was passed
o v e r th e c h ar bed, sm all amounts of s u l f u r were re c o v e re d .
W ith a temp­
e r a tu r e o f 595°C and a fe e d r a t e o f 2 .5 4 m oles o f s u lf u r d io x id e p e r h o u r,
a 1 4 .8 p e rc e n t y i e l d o f s u l f u r was o b ta in e d and when a te m p e ra tu re of
593°C and a fe e d r a t e . o f 1 .9 7 m oles of s u lf u r d io x id e were u se d , a 14.3
p e rc e n t y i e l d o f s u lf u r was o b ta in e d . ■The thermodynamic c a lc u la tio n s
in d ic a te d t h a t h ig h e r te m p e ra tu re s would r e s u l t in b e t t e r c o n v ersio n t o
s u l f u r , b u t i t was f e l t t h a t th e h ig h c o s t o f b u ild in g , h ig h -te m p e ra tu re '
equipm ent was n o t w a rra n te d .
The p o s s i b i l i t y o f p a s s in g s u lf u r d io x id e th ro u g h a f l u i d i z e d bed o f
c h a r was a ls o in v e s t i g a t e d .
By c a r ry in g ou t th e re d u c tio n o f s u lf u r d io x ­
ide, i n a f l u i d i z e d c h a r b e d , th e in h e r e n t a d v an tag es o f a f l u i d i z e d bed.
- 14 good m ixing and te m p e ra tu re c o n tr o l, co u ld be r e a l i z e d .
Work was done to
i n v e s t i g a t e th e f l u i d i z a t i o n c h a r a c t e r i s t i c s o f c h ar u s in g f o u r d i f f e r e n t
m ix tu re s o f c h ar s iz e d betw een 20 and 100 mesh (T able I I ) .
A lthough th e
m ix tu re h av in g th e s m a lle s t p a r t i c l e s iz e co u ld be f l u i d i z e d , th e c o a l
c h a r d id n o t e x h ib it good f l u i d i z a t i o n p r o p e r t i e s .
There was a marked
te n d e n c y f o r slu g g in g t o o c c u r, and u n d er no c o n d itio n s was i t p o s s ib le
t o o b ta in a good f l u i d c o n d itio n ^
In view o f th e p oor f l u i d i z a t i o n c h a r a c t e r i s t i c s o f th e c o a l ch ar
and th e h ig h te m p e ra tu re s t h a t were in d ic a te d t o be n e c e s s a ry when u sin g
a f ix e d c h a r b e d , i t was f e l t t h a t c h ar d id n o t a p p e a r a s fa v o ra b le a s
n a t u r a l gas a s a re d u c in g a g e n t.
T h e re fo re , th e in v e s t i g a t i o n was
d iv e r te d t o . g e t more com plete in fo rm a tio n on th e re d u c tio n o f s u lf u r
>
d io x id e w ith n a t u r a l g a s.
R eduction o f S u lfu r D ioxide U sing Methane a s th e Reducing A g en t.
' ?,
A. 'Two R e a c tio n Zones i n S e r ie s ;
P re v io u s work c a r r ie d o u t by D avis (3) in d ic a te d t h a t s u lf u r
co u ld be o b ta in e d by re d u c in g s u lf u r d io x id e w ith m eth an e.
In view
o f th e f a c t t h a t hydrogen s u lf id e a s w e ll a s s u lf u r i s form ed in
t h i s r e a c tio n , i t was proposed to in c r e a s e th e s u lf u r y i e l d :by
•re a c tin g th e hydrogen s u lf id e w ith u n re a c te d s u lf u r d io x id e in a
second r e a c tio n zone.
A s e r i e s o f ru n s was s e t up to c a r ry out
th e s e two r e a c tio n s in s e r i e s .
The f i r s t ru n s were made w ith two
c a t a l y s t beds i n s e r i e s i n one r e a c t o r .
L a te r-ru n s were made
c a r ry in g th e two r e a c tio n s o u t i n s e r i e s b u t i n s e p a ra te r e a c t o r s .
- 15 An a tte m p t was made t o h o ld th e te m p e ra tu re of th e f i r s t r e a c tio n
zone i n th e ran g e o f 550°G a n d 't h a t o f th e second r e a c tio n zone a t
350°C.
P re v io u s work done by D avis (3) had i n d ic a te d t h a t th e r e ­
a c tio n betw een s u lf u r d io x id e and methane a t 550°C r e s u l t e d in a 53 p e rc e n t y ie ld o f s u lf u r and a ls o r e s u lte d in an o f f - g a s c o n ta in in g
hydrogen s u lf id e and s u lf u r d io x id e i n a r a t i o o f 2 t o I , which i s
what i s r e q u ir e d f o r th e r e a c tio n between hydrogen s u l f i d e and s u lf u r
d io x id e t o form s u l f u r .
A te m p e ra tu re o f 350°C was chosen a s th e
te m p e ra tu re o f th e second r e a c tio n zone s in c e th e r e a c tio n i s c a r r ie d
o u t com m ercially a t a p p ro x im a te ly t h a t te m p e ra tu re .
xI The a tte m p t to run th e two r e a c tio n s — methane w ith s u lf u r
d io x id e and hydrogen s u l f i d e w ith s u lf u r d io x id e — in one r e a c to r
1
was u n s u c c e s s fu l s in c e th e le n g th o f th e r e a c to r and arrangem ent o f j
th e h e a tin g c o i l s p re v e n te d th e a tta in m e n t o f th e d e s ir e d tem p era tu r e s i n th e two r e a c tio n zo n es.
When th e c a t a l y s t beds were
p o s itio n e d i n s e p a ra te r e a c to r s and th e te m p e ra tu re s o f th e two r e ­
a c tio n zones h e ld a t 553 C and 378°C5 r e s p e c tiv e ly , o n ly a 2 .4
p e rc e n t y i e l d o f s u l f u r was o b ta in e d .
S in ce b o th o f th e r e a c tio n s
u n d er c o n s id e ra tio n were knpwn t o produce s u l f u r , t h i s lo w 'y ie ld
in d ic a te d t h a t th e second r e a c tio n , t h a t between hydrogen s u lf id e
and s u lf u r d io x id e , was p ro b a b ly b e in g i n h i b i t e d by one o r more o f
th e o th e r components o f th e gas m ix tu r e .
I t f u r t h e r in d ic a te d t h a t
th e r e was some c o n v ersio n o f th e s u lf u r form ed i n th e f i r s t r e a c tio n
to . o th e r p ro d u c ts , and t h i s was l a t e r s u b s ta n tia te d by th e r e s u l t s
o f a s tu d y made on c a t a l y s t bed p o s i t i o n .
’
- 16 B-.
C a ta ly s t Bed P o s itio n and P re h e a t T em p eratu res.
In th e work c a r r ie d o u t w ith two r e a c tio n zones, th e p o s s i b i l i t y
o f s u lf u r b e in g c o n v e rte d to o th e r p ro d u c ts a f t e r le a v in g th e c a t a l y s t
bed was re c o g n iz e d .
A s e r i e s of ru n s was u n d e rta k en i n which a s in g le
c a t a l y s t bed was moved to v a rio u s p o s itio n s in th e r e a c t o r t o d e te r ­
mine th e e f f e c t o f th e bed p o s itio n i n th e r e a c t o r .
S in ce th e s tu d y
o f bed p o s itio n in d ic a te d s h a rp ly d e c re a sin g ,.y ield s a s th e bed was
moved upward i n the. r e a c t o r (T able I I I and F ig . 6) , i t became n e c ­
e s s a r y t o d eterm in e w h eth er th e d e c re a se d y ie ld s were due t o th e
s h o r te r p re h e a t s e c tio n which r e s u lte d a s th e c a t a l y s t bed was moved
upward
o r from a c o n v ersio n o f th e s u lf u r to o th e r p ro d u c ts o ccu r­
r in g i n th e packed zone below th e bed .
A s e r i e s o f ru n s was th e n
made to d eterm in e th e e f f e c t of p re h e a t on th e s u l f u r re c o v e ry .
F ig u re 7 and T able IV i l l u s t r a t e t h a t when th e c a t a l y s t bed
'was a t th e bottom o f th e r e a c t o r , th e c o n v ersio n to s u l f u r in c re a s e d
s l i g h t l y a s th e p re h e a t was d e c re a se d .
When o p e ra tin g w ith a p re h e a t
o f 523°C, a s u lf u r y i e l d o f 5 0 .4 p e rc e n t was o b ta in e d .
When th e c o i l
su p p ly in g h e a t to th e p re h e a t s e c tio n was sh u t o f f , th e te m p e ra tu re
i n th e p re h e a t s e c tio n dropped to 228°C and a s u lf u r y i e l d of 65.3
p e rc e n t was o b ta in e d .
A lthough a s l i g h t in c re a s e i n y i e l d seems to
be in d ic a te d when th e r e a c tio n i s c a r r ie d out w ith o u t a p re h e a t
s e c tio n , th e p re h e a t s e c tio n seems t o have l i t t l e e f f e c t on th e s u lf u r
re c o v e ry o th e r th a n t o in s u r e t h a t th e incom ing g a se s were th o ro u g h ly
m ixed when th e y re a c h e d th e c a t a l y s t b ed .
The r e s u l t s of t h i s p re h e a t
- 17 s tu d y coupled w ith th e r e s u l t s o f th e s tu d y on c a t a l y s t bed p o s itio n
le a d to th e c o n c lu sio n t h a t th e r e must have been a c o n v ersio n of s u l­
f u r t o o th e r p ro d u c ts , and tlia t th e r e a c tio n p ro d u c ts should 'be r e ­
moved from th e r e a c t o r and co o led a s soon, a s p o s s ib le a f t e r th e y a re
form ed.
G. T em perature
Follow ing th e s tu d y on p r e h e a t, a s e r i e s o f ru n s was made w ith
th e c o i l on th e p re h e a t s e c tio n tu rn e d o f f , in o rd e r t o d eterm in e th e
e f f e c t o f r e a c tio n te m p e ra tu re on th e s u lf u r y i e l d .
The r e s u l t s
a p p e a r i n T able V and a re g r a p h ic a lly i l l u s t r a t e d i n F ig . 8 .
A max­
imum c o n v ersio n o f ab o u t 65 p e rc e n t was o b ta in e d a t an av erag e bed
te m p e ra tu re o f 546°G.
T his co n v ersio n was o n ly th r e e p e rc e n t h ig h e r
th a n t h a t r e p o r te d by B avis ( 3 ) , b u t th e te m p e ra tu re a t which th e
maximum s u lf u r y i e l d o c c u rre d was I ? 0C low er th a n he r e p o r te d .
T his
d e v ia tio n in optimum te m p e ra tu re s le d t o an i n v e s t ig a ti o n of tem per­
a tu r e g ra d ie n t th ro u g h o u t th e c a t a l y s t bed.
Up t o t h i s p o in t i n th e i n v e s t ig a ti o n th e av erag e te m p e ra tu re in
th e c a t a l y s t bed had been d eterm in ed by u s in g two th erm o co u p les
spaced a t ab o u t 4 - i n . i n t e r v a l s i n a 1 2 - in . c a t a l y s t b e d .
I n o rd e r
t o stu d y more th o ro u g h ly th e te m p e ra tu re g r a d ie n t, a t h i r d therm o­
couple was in s e r t e d i n t o th e bed and th e th r e e th erm o co u p les were
spaced a t a b o u t 3 - i n . i n t e r v a l s .
Under t h i s arrangem ent i t became,
e v id e n t t h a t th e te m p e ra tu re i n th e c e n t r a l p o rtio n o f th e c a ta ly s t
bed was h ig h e r th a n a t e i t h e r end.
A te m p e ra tu re g r a d ie n t of t h i s
- 18 ty p e i s q u ite common w ith exotherm ic r e a c tio n s .
In view o f t h i s
te m p e ra tu re g r a d ie n t i t i s a p p a re n t t h a t th e te m p e ra tu re o f 546°C
found t o be th e optimum i n F ig . 8 was n o t th e t r u e a v e ra g e , and th e
a c t u a l te m p e ra tu re was h ig h e r th a n t h a t b e in g m easured.
There i s
a p o s s i b i l i t y t h a t th e optimum te m p e ra tu re , 563°C, r e p o r te d by D avis
( 3 ) was n e a r ly c o r r e c t s in c e he was o p e ra tin g w ith p re h e a t tem per­
a tu r e s o f about 510°G.
T his p re h e a t would p ro b a b ly move th e h ig h -
te m p e ra tu re sp o t up th e r e a c tio n zone and i n t o th e v i c i n i t y of th e
p o in t where he was a c t u a l l y m easuring th e te m p e ra tu re .
When oper­
a tin g w ith o u t th e p r e h e a t, however, th e maximum te m p e ra tu re o ccu r­
re d below th e f i r s t therm ocouple and was n o t d e te c te d by th e
th erm o co u p le.
A more in te n s iv e exam in atio n o f how te m p e ra tu re g r a d ie n ts
a c r o s s th e c a t a l y s t bed m ight in f lu e n c e s u lf u r y ie ld s was n e x t
u n d e rta k e n .
B efo re making t h i s s tu d y , how ever, th e u n i t was r e ­
v is e d to a llo w f o r a l i n e - o u t p e rio d p r i o r to th e a c t u a l ru n .
P r e v io u s ly , th e e r r a t i c l i n e - o u t p e rio d had been an i n t e g r a l p a r t
o f th e ru n , and in ru n s o f s h o rt d u ra tio n t h e ..e r r o r in tro d u c e d by
n o t having s te a d y - s ta te c o n d itio n s th ro u g h o u t th e ru n co u ld be of
c o n s id e ra b le m ag n itu d e.
D ata f o r th e ru n s c a r r ie d ou t d u rin g th e te m p e ra tu re -g ra d ie n t
s tu d y a r e shown i n T able V I.
For t h i s d is c u s s io n th e te m p e ra tu re s
a s m easured by th e to p , m id d le, and bottom therm ocouples w i l l be
r e f e r r e d t o a s T^, T^, and T^, r e s p e c t i v e l y .
The d a ta in T able VI
/
- 19 -
i n d i c a t e a tr e n d tow ard an in c r e a s e i n s u l f u r re c o v e ry i f th e
te m p e ra tu re i n th e up p er p a r t o f th e r e a c tio n zone i s h e ld down
and t h a t i n th e low er p o r tio n h e ld in th e re g io n ' of 560°C.
F ig u re
9 i n d i c a t e s th e r e l a t i o n s h i p between th e s u lf u r y ie ld and th e temp­
e r a tu r e o f th e ' low er p a r t of th e r e a c tio n zone when T1 was h e ld be­
tw een 525°G and 531°C.
I t i l l u s t r a t e s t h a t th e c o n v ersio n t o s u l­
f u r in c re a s e d from ab o u t 64 p e rc e n t t o S i p e rc e n t a s th e av erag e
o f Tg and T^
in c re a s e d from 535°C t o 560°G„
F ig u re 10, a s im ila r
p l o t , sh o w s-th a t when T1 was h e ld betw een 533°C and 540°C, th e
co n v ersio n t o s u l f u r began t o d e c re a se when th e av erag e o f T2 and
T^ exceeded 560°C.
F ig u re 11 shows p e rc e n ta g e c o n v ersio n v e rs u s
T1 w ith th e a v erag e o f T^ and T^ h e ld betw een 557°G and $65°G.
It
i n d ic a te s t h a t th e s u lf u r re c o v e ry can be in c re a s e d by lo w e rin g T1 .
There i s a l i m i t , how ever, t o how low th e te m p e ra tu re in th e
u p p er p o r tio n o f th e bed can be red u ced w ith o u t a ls o re d u c in g th e
te m p e ra tu re i n th e rem ain in g p a r t o f th e bed below th e d e s ir e d
te m p e ra tu re .
With th e r e a c to r used i n t h i s stu d y , t h i s l i m i t was
about 52$°C.
When T1 was reduced below 525°C, th e s u l f u r y ie ld s
d e c re a se d , b u t t h i s d e c re a se i n y i e l d can be a t t r i b u t e d t o reduced
te m p e ra tu re s th ro u g h o u t th e e n t i r e r e a c tio n zone.
The in flu e n c e
o f te m p e ra tu re a p p e a rs t o be q u ite c r i t i c a l on th e co n v ersio n to
s u lfu r.
S ince p r e c is e te m p e ra tu re c o n tr o l of th e v a rio u s zones was
d i f f i c u l t , some of. th e d i f f i c u l t i e s i n re p ro d u c in g r e s u l t s can
p ro b a b ly be a cc o u n te d f o r by t h i s c r i t i c a l e f f e c t of te m p e ra tu re „
- 20 -
The o v e r a ll p ic tu r e t h a t r e s u l t s from t h i s stu d y in d ic a te s t h a t
te m p e ra tu re s i n th e range o f 560°C a re -m o st fa v o ra b le f o r th e max­
imum c o n v ersio n t o s u lf u r .
F ig u re 12 shows th e o v e r a ll av erag e te m p e ra tu re of th e r e a c tio n
bed v e rs u s th e co n v ersio n to s u l f u r , and in c lu d e s a l l th e ru n s
l i s t e d i n Table V I.
The optimum te m p e ra tu re f o r co n v ersio n t o s u l­
f u r i s in d ic a te d to be 549°C.
Much o f th e v a r ia tio n i n s u lf u r
y i e l d s can be a cc o u n te d f o r by th e d i f f e r e n t te m p e ra tu re d i s t r i ­
b u tio n s t h a t r e s u l t e d i n s im ila r av erag e te m p e ra tu re s .
F ig u re s
13 and 14 a r e th e same a s F ig . 12 w ith th e e x c e p tio n t h a t th e y use
Tg and th e a v erag e o f Tg and T^, r e s p e c tiv e ly , in p la c e o f th e
o v e r a ll av erag e te m p e ra tu re .
E i th e r o f th e s e c u rv e s p ro b a b ly
g iv e s a b e t t e r p ic tu r e o f th e a c t u a l optimum te m p e ra tu re .
c a s e s t h i s optimum f a l l s i n th e re g io n o f 560°G.
I n both
I t a p p ea rs
re a so n a b le to assume from t h i s s tu d y t h a t s in g le - p a s s y ie ld s up t o
SP' p e rc e n t m ight be expected w ith v e ry c lo s e te m p e ra tu re c o n tr o l.
I t sh ould be p o in te d o u t t h a t th e co n v ersio n of 70 t o 80 •
p e rc e n t which were o b ta in e d c o n s is te n tly i n t h i s i n v e s t ig a ti o n
a re 10 t o 20 p e rc e n t h ig h e r th a n th o s e re p o rte d by D av is.
Most o f
t h i s in c r e a s e can be a t t r i b u t e d t o c lo s e r te m p e ra tu re c o n tr o l and
rem oval o f th e e r r a t i c l i n e - o u t p e rio d from th e a c t u a l ru n .
D.
Feed E a te
The in f lu e n c e o f th e fe e d r a t e t o th e r e a c to r i s i l l u s t r a t e d
i n F ig . 15' and T able y i l „
The maximum c o n v ersio n to s u l f u r , ?8
•
21 p e r c e n t, was o b ta in e d a t ab o u t 8 gram-moles o f fe e d p e r h o u r.
The
c o n v ersio n i s shown t o have dropped to 60 p e rc e n t a t 10 gram-moles
p e r hour and to 32 p e rc e n t a t 6 gram-moles p e r h o u r.
A more ex­
te n s i v e stu d y o f t h i s p a r t i c u l a r v a r ia b le would be d e s ir a b le to
d e fin e more c l e a r l y th e in f lu e n c e of fe e d r a t e on th e c o n v ersio n
o f s u lf u r d io x id e to s u l f u r .
E.
Mole R a tio
The d a ta a p p e a rin g in T able V III , when p re s e n te d g r a p h ic a lly
i n F ig . 16, i l l u s t r a t e s th e in flu e n c e o f th e mole r a t i o o f methane
t o s u lf u r d io x id e on th e s u l f u r re c o v e ry .
A r a t i o o f 3*7 m oles of
m ethane t o one mole o f s u l f u r d io x id e i s seen to have g iv en a max­
imum p e rc e n ta g e co n v ersio n to s u l f u r o f 74 p e r c e n t.
I n th e range
o f th e o p e ra tin g c o n d itio n s t h a t were s tu d ie d , th e e f f e c t of mole
r a t i o on th e re d u c tio n to s u lf u r seems t o be l e s s th a n t h a t o f
te m p e ra tu re and fe e d r a t e .
The s u lfu r- re c o v e ry i s shown to de­
c re a s e t o 54 p e rc e n t a t a mole r a t i o o f methane to s u lf u r d io x id e
of 2 , and to d e c re a se t o 66 p e rc e n t a t a r a t i o o f 5 m oles o f
methane t o I mole o f s u l f u r d io x id e .
F.
C a ta ly s t A c tiv ity
In th e co u rse of th e s e i n v e s t ig a ti o n s a d e c re a se i n th e
maximum c o n v ersio n to s u lf u r was o b se rv e d .
t o be due to a lo s s of c a t a l y s t a c t i v i t y .
T his d e c re a se was found
The r a t e o f lo s s of
c a t a l y s t a c t i v i t y i s shown in F ig . 17 which was p l o t t e d u s in g th e
d a ta i n T able IX .
- 22 I f th e assum ption i s made t h a t F ig . 17 i l l u s t r a t e s a l i n e a r
r e l a t i o n s h i p betw een c a t a l y s t a c t i v i t y and th e h o u rs th e c a t a l y s t
had been in u s e , th e method o f l e a s t sq u a re s can be u sed t o f i t a
l i n e a r e q u a tio n to t h i s d a ta .
T h is r e s u l t s i n th e e q u a tio n
y = 7 4 .7 -
0 . 1l 6x
where
y = p e rc e n ta g e c o n v ersio n t o s u lfu r,- and
x = h o u rs t h a t th e c a t a l y s t had been in u s e .
E xam ination of t h i s e x p re ss io n ..lead s to t h e c o n c lu sio n t h a t
f o r ev ery IG h o u rs th e c a t a l y s t was u se d , th e re d u c tio n to s u lf u r
was d e c re a se d by 1 .1 6 p e r c e n t.
I t i s fu r th e r illu s tr a te d th a t a
maximum co n v ersio n to s u lf u r o f 74-7 p e rc e n t can be ex p ected w ith
fre sh c a ta ly s t.
The d a ta used to d ev elo p t h i s e x p re ss io n were ta k en
from ru n s made a t s im ila r av erag e te m p e ra tu re s , mole r a t i o s , and
fe e d r a t e s .
S ince th e av erag e te m p e ra tu re s were n o t a l l o b ta in e d
u n d er what a p p e a rs to be th e optimum te m p e ra tu re d i s t r i b u t i o n
th ro u g h o u t th e c a t a l y s t b ed , and s in c e th e s e ru n s were ta k e n from
a lo n g s e r i e s o f ru n s made a t a g r e a t v a r i e t y o f c o n d itio n s , i t
should ,be p o in te d o u t t h a t t h i s e x p re s s io n does have l i m i t a t i o n s .
I t does o f f e r an i n d ic a tio n o f how c a t a l y s t l i f e in flu e n c e s
th e c o n v ersio n to s u l f u r , how ever, and i n an a tte m p t t o p re s e n t th e
r e s u l t s on a more com parable b a s i s , th e s lo p e of th e e q u a tio n was
u sed t o c o r r e c t some o f th e c o n v e rsio n s o b ta in e d in t h i s stu d y t o
th e c o n v e rsio n s t h a t would t h e o r e t i c a l l y have been o b ta in e d i f th e
- 23 -
c a t a l y s t had been used zero h o u rs „
F ig u re s 9 th ro u g h 16 were a l l
p l o t t e d u s in g th e s e c o rre c te d v a lu e s f o r c o n v ersio n o f s u lf u r
d io x id e to s u l f u r .
SUMMARY
C oal c h ar was in v e s t ig a te d a s a re d u c in g a g en t f o r s u lf u r d io x id e .
S e v e ra l ru n s were made o v er a f ix e d bed o f c h a r, and work was done to
d eterm in e th e f l u i d i z a t i o n c h a r a c t e r i s t i c s o f c h a r.
S in ce h ig h tem per­
a t u r e s were in d ic a te d to be r e q u ir e d when u s in g a f ix e d b ed , and sin c e
th e c h a r seemed t o have p oor f l u i d i z a t i o n c h a r a c t e r i s t i c s , n a t u r a l gas
a p p ea re d to be more fa v o ra b le th a n c h ar a s a re d u c in g a g e n t.
The work done on c a r ry in g ou t two r e a c tio n s , a r e a c tio n between
m ethane and s u l f u r d io x id e fo llo w e d by a r e a c tio n betw een hydrogen s u l­
f i d e and u n re a c te d s u lf u r d io x id e , i n s e r i e s , r e s u lte d i n v e ry sm all
s u lf u r y i e l d s .
These low y i e l d s in d ic a te d t h a t th e s u lf u r form ed in th e
f i r s t r e a c tio n was bein g c o n v erted to o th e r p ro d u c ts and t h a t th e second
r e a c t i o n , t h a t betw een hydrogen s u lf id e and s u lf u r d io x id e , was [probably
';
i n h i b i t e d by th e o th e r components i n th e m ix tu re .of g a s e s .
I t was d eterm in ed t h a t y ie ld s dropped s h a rp ly when th e c a t a l y s t bed
was moved up th e r e a c t o r .
S ince th e e f f e c t o f rem o v in g /p reh e at in c re a s e d
V'
'
-
:
th e y i e l d s l i g h t l y , th e d e c re a se in y i e l d s a s t h e c a t a l y s t bed w a s -
-v
-
I i
•
v.:
-
- I '
moved up was a t t r i b u t e d to a co n v ersio n o f s u lf u r to ,o th e r 'p r o d u c t's 'in
\
th e packed zone below th e c a t a l y s t b e d . I t was c o n c lu d e d " th a t th e r e •
’
>
a c ti o n p ro d u c ts sh o u ld be co o led a s soon a s p o s s ib le a f t e r th e y le a v e
th e c a t a l y s t b ed .
■'
.,V
'
.
-
-
— 24 —
The in f lu e n c e o f te m p e ra tu re on th e co n v ersio n t o s u lf u r when o p er­
a tin g w ith o u t p re h e a t was in v e s t i g a t e d .
The i n i t i a l r e s u l t s le d to an
in v e s t i g a t i o n o f a p o s s ib le te m p e ra tu re g ra d ie n t th ro u g h th e c a ta ly s t
bed.
W ith th e a d d itio n o f a t h i r d therm ocouple i n t o th e c a t a l y s t bed
i t was d eterm in ed t h a t th e c e n t r a l p a r t of th e r e a c tio n zone was a t a
h ig h e r te m p e ra tu re th a n e i t h e r end.
The e r r a t i c l i n e - o u t p e rio d was
removed from th e a c t u a l run and an in te n s iv e stu d y was u n d e rta k en to
d eterm in e how th e te m p e ra tu re g ra d ie n t in flu e n c e d th e s u l f u r y i e l d s .
The in f lu e n c e of te m p e ra tu re was fo u n d to be q u ite c r i t i c a l ,
and b e s t r e s u l t s w ere o b ta in e d when th e u p p e r p a r t o f th e r e a c tio n zone
was o p e ra te d a s low a s p o s s ib le c o n s is te n t w ith m a in ta in in g th e low er
p o r tio n o f th e zone a t ab o u t 560°C.
I t was concluded t h a t w ith c lo se
te m p e ra tu re c o n tr o l and th e rem oval o f th e l i n e - o u t p e rio d from th e
a c t u a l ru n , s u l f u r r e c o v e r ie s up to 80 p e rc e n t m ight be ex p ected when
u s in g f r e s h c a t a l y s t .
The optimum fe e d r a t e seemed t o be a t 8 gram-moles o f fe e d p e r hour
when u s in g 400 gm of c a t a l y s t .
More d a ta would have been d e s ir a b le ,
how ever, t o f i x more a c c u r a te ly th e fe e d r a t e .
The mole r a t i o o f th e r e a c ta n ts a p p ea re d t o have l e s s in flu e n c e on
th e s u lf u r re c o v e ry th a n e i t h e r te m p e ra tu re o r fe e d r a t e , b u t a maximum
s u lf u r co n v ersio n was o b ta in e d a t a mole r a t i o o f 3 .7 m oles o f methane
t o I mole o f s u lf u r d io x id e .
The c a t a l y s t a c t i v i t y was shown t o d e c re a se a p p ro x im a te ly l i n e a r l y
w ith r e s p e c t t o tim e .
Tfflrien a l i n e a r r e l a t i o n s h i p was assum ed, an ex r
- 25 -
p r e s s io n was developed which approxim ated t h i s d e c re a se i n c o n v ersio n
t o s u lf u r due to lo s s o f c a t a l y s t a c t i v i t y a s b e in g I „ l 6 p e rc e n t f o r
each 10 h o u rs th e c a t a l y s t was in u s e .
ACKNOWLEDGMENT
The a u th o r w ishes t o th a n k th e E n g in e e rin g Experim ent S ta tio n a t
Montana S ta te C o lleg e f o r sp o n so rin g t h i s re s e a rc h p r o j e c t , and P ro fe sso rs
H. A. S a n e r, Lloyd B erg, and E. L. N ic k elso n f o r t h e i r s u g g e s tio n s and
c ritic is m s
- 26 -
BIBLIOGRAPHY
1.
B osw ell, M. C ., U. S. P a te n t No. 1 ,8 8 0 ,7 4 1
2.
Chem ical E n g in e e rin g , 59
3.
D av is, W illa rd F . , R eduction o f S u lfu r D ioxide to E lem en tal S u lfu r
Using Methane Eis th e R educing A gent; T h e s is , Montana S ta te C o lle g e,
(S e p t. 1 9 5 6 ).
4-
F lem ing, E. P 6, and F i t t , T. C .,
G ases, I n d . & E n g , -ChGm. . 42
5.
Lundy, W. T ., Known and P o t e n t i a l S u lf u r R esources o f th e W orld;
I n d . & E n g .' Chem. ' , . 2^2
2199 (1950}.
/
165
(O ct. 4 , 1 9 3 2 ). ■
(Ju n e , 19 5 2 ).
High P u r ity S u lf u r From S m elter
2249 (195071
Z
- 27 -
APPENDIX
T able I
Page
Thermodynamic I n v e s tig a t io n o f Coal
Char a s a R educing A g en t
.
. 29
.
.
31
.
.
32
,
.
33
.
.
34
........................................................................................... ..................
T ab le I I
P a r t i c l e S iz e o f Sam ples.Used in
F lu i d iz a tio n T e s ts .
........................................
.
T able I I I
E f f e c t of Bed P o s itio n on S u lf u r R ecovery
T able IV
E f f e c t o f P re h e a t on S u lf u r R ecovery.
T able V
E f f e c t o f Tem perature on S u lf u r Recovery
T ab le YI
E f f e c t o f T em perature G ra d ie n t on
•S u lfu r R ecovery. . . . . . .
.
.
■ .
.
.
.
.
T able H I
E f f e c t o f Feed R ate on S u lf u r R ecovery.
T able V III
E f f e c t o f Mole R a tio on S u lf u r Recovery
.
.
36
T able IX
E f f e c t of C a ta ly s t A c tiv ity on S u lfu r
R ecovery .
. . . . .
.
.
37
.
38
.
.
39
.
.
40
O
6
i^l
.
.
.
42
.
.
.
43
AA
.
.
.
.
-
35
F ig u re I
B lock Flow Diagram
F ig u re 2
Diagram o f S u lf u r D ioxide R eduction U n it'
F ig u re 3
Diagram o f R e a c to r
F ig u re 4
Diagram o f C o n sta n -tem p e ra tu re Condenser .
F ig u re 5
Diagram o f S u lf u r R e c e iv e r
F ig u re 6
P e rc e n t Y ie ld v s . Bed P o s itio n .
F ig u re 7
P e rc e n t Y ie ld v s . ,P reh eat Tem perature
e
0
F ig u re 8
P e rc e n t Y ie ld v s . T em perature
•
. 45
F ig u re 9
P e rc e n t Y ie ld v s . Average o f T9 and T
^
3
.
.
.
.
.
.
.
.
.
.
.
.
.................................................................................................................................................■
.
.
.
.
.
.
.
.
.
.
.
.
„
.
..........................................................................
.
,
46
- 2d -
APPENDIX (c o n tin u e d )
F ig u re 10
P e rc e n t Y ie ld v s . Average o f Tg and
F ig u re 11
P e rc e n t Y ie ld v s . T^
F ig u re 12
P e rc e n t Y ie ld v s . Average Tem perature
F ig u re 13
P e rc e n t Y ie ld
F ig u re 14
P e rc e n t Y ie ld v s . Average o f Tg and T^
.
'5 1
F ig u re 15
P e rc e n t Y ie ld v s . Feed R ate ..............................................
52
F ig u re 16
P e rc e n t Y ie ld v s . Mole R a tio .
53
F ig u re 17
P e rc e n t Y ie ld v s . O n-stream Hours .
"V"S o
T^
e
i
e
e
.
47
.................................
48
e
. . .
.
e
e
.
e
.
o
.
. . .
.
.
50
o
. . . . . . . .
.
49
.
.
54
- 29 -
THERMODHfAMIC INVESTIGATION OF COAL CHAR AS REDUCING AGENT
The fo llo w in g f o u r r e a c tio n s were p o s tu la te d a s p o s s ib le mechanisms
i n th e re d u c tio n of s u lf u r d io x id e to s u l f u r u s in g c o a l c h ar (c o n sid e re d
t o be g r a p h ite c arb o n ) a s th e re d u c in g a g e n t:
I.
ZSOgfg)
+
20 (g r)
S2 (g )
+ : 2002(g)
i'
2.
4502(g)
+
^c Cgr)
Sz(g)
+ . 4002(g)
3.
% :°2(g)
+ '4 c Cgr)
^2 (g )
+
400(g)
4«
^ 2 (g )
+
82(g)
+
800(g)
9° ( g r )
+
OSgfg)
+ 082(g)
The r e s u l t s of th e thermodynamic c a lc u la tio n s in in v e s t i g a t i n g
th e s e r e a c tio n s a p p ea r in T able I .
A ll v a lu e s f o r th e e q u ilib riu m con­
s t a n t s were c a lc u la te d a t 500oC.
TABLE I
R ea c tio n
A F 298
(c a l/m o le )
Tem perature o f N e u tra l
E q u ilib riu m
K
eq
(°K)
I
-2 5 ,5 4 0
, -435
8 .9 x IO11
2
-5 4 ,1 7 0
' -4 6 4
3
31,500
563
7 .9 5 x 10^4
7
1 .2 6 x 10
4
59,830
549
1 .2 6 x IO15
- 30 -
TABLE I I
P a r t i c l e S iz e o f Samples Used i n F lu i d iz a tio n T e s ts
Sample No.
S creen Mesh
Weight F r a c tio n R etain ed
I
- 20
- 2d
- 35
— 48
- 65
-100
+ 28
+ 35
+ 48
+ 65 +100
0 .1 0
0 .6 0
0 .1 $
0 .0 $
0 .0 5
0 .0 $
2
- 20
- 28
- 35
- 48
- 65
-100
+ 28
+ 35
+ 48
+ 65
+100
0 .1 0
o .$ o
0 .2 0
0 .1 0
0 .0 $
0 .0 $
3
- 20
- 28
- 35
- 48
- 65
-100
+ 28
+ 35
+ 48
+ 65
+100
0 .1 $
0 .4 0
0 .2 0
0 .1 0
0 .1 0
0 .0 $
4
- 20
- 28
- 35.
- 48
- 65
-100
+ 28
+ 35
+ 48
+ 65
+100
0 .0 $
0 .4 0
0 .3 0
0 .1 0
0 .1 0
0 .0 $
TABLE I I I
E f f e c t o f Bed P o s itio n on S u lf u r Recovery
■ Moles SOg
per h r.
3 .5 7
1 .7 5
8 .0 1
0
50.40
540
3 .6 8
1 .7 0
7 .9 6
5
41.60
BP - 3
535
3 .6 4
1.72
7 .9 8
5
3 7 .6 0
BP - 4
544
3 .5 8
1.75
8 .0 1
.10
5.95
BP - 5
536
3 .7 0
1 .6 9
7 .9 5
10
0 .6 2
,
BP - 6
540
3 .6 2
1 .7 3
7 .9 9
2
51.20
H
i
Average
Temp. 0C
B P-I
548
BP - 2
.
T o ta l
gram-moles
per h r.
In c h e s From
R ea c to r Bottom
to C a ta ly s t Bed
Mole R a tio
OH4ZSO2
Run No.
# SOgz
C onverted •
to S
TABLE IV
E f f e c t o f P re h e a t on S u lfu r Recovery
Run No.
Ave. Temp. 0C
Hole R a tio
OH^/SOg
Moles SO2
per h r.
T o ta l
gram-moles
per h r.
P re h e a t
T em perature
C
# SOg
C onverted
to S
B P-I
548
3 .5 7
1 .7 5
8 .0 1
523
50 .4
P r - I
550
3 .7 0
1 .6 9
7 .9 5
476
64.O ■
Pr - 2
550.
3 .6 0
1 .7 4
8.0 0
425
62 .0
Pr - 3
550
3 .5 0
1 .7 9
8 .0 $
349
5 8 .0
Pr - 4
550
3 .4 1
1 .8 4
8,10
255
64.O
Pr - 5
547
3 .6 0
1 .7 4
8 .0 0
228
65.3
-
TABLE V
E f f e c t o f Tem perature on S u lfu r Recovery
(T em peratures re a d w ith two th erm o co u p les)
Moles SOg
per h r.
T o ta l
gram-moles
per h r.
Ave. Temp. 0C
1 .7 7
8.0 3
563
20.6$
3 .5 7 .
1 .7 5 -
8 .0 1
527
54.00
TA - 3
3 .5 5
1 .7 6
8 .0 2
540
62.50
TA - 4
3 .4 4
1 .8 2
8 .0 8
556
3 7.10
TA - 5
3 .5 2
1 .7 8
8 .0 4
518
52.50
TA - 6
3 .5 7
1 .7 6
8 .0 2
555
4 4.00
TA - 7
3 .6 0
.1 .7 4
8 .0 0
552
55.70
Pr - 5
3 .6 0
1 .7 4
8 .0 0
547
65.30
Run No.
Mole R atio
CH4ZSO2
TA - I
3 .5 4
TA - 2
# SOg
C onverted
to S
I
TABLE H
E f fe c t o f Tem perature G ra d ie n t on S u lf u r Recovery
(T em peratures read w ith th r e e th erm o co u p les)
Run No. .
TB - I
TB - 2
TB - 3
T B '- 4
TB - 5
TB
6
TB - 7
TB - 8TB - 9
TB - 10
TB - 11
TB - 12
TB - 13
TB - 14
TB - 15
TB - 16
TB - .1 7
FR - 6
MR - 8
Mole R atio
CH4ZSQ2
4 .0 5
3 .6 7
3 .8 o
. 3 .7 9
% 3 ;5 8
- 3 .4 8
3 .5 1
3.75
3 .7 1
- 3 .4 7
3 .6 2
3 .5 9
3 .6 8
3 .8 2
-3 .6 0
3 .5 6
3 .7 1
3 ;4 8
' 3 .7 6
Moles SO2
per h r.
1.55
1 .7 1
1.65
1.65
1.75
1 .8 0
1 .7 9
' 1.67
1 .6 9
1 .8 1
1.73
1.75
1 .7 0
1 .6 4
1 .7 4
1 .7 6
1 .6 9
1 .8 0
1.66
T o ta l
gram-moles
per h r.
T1
7 .8 1
7 .9 7
7 .9 1
7 .9 1
8 .0 1
8 .0 6
8.0 $
7.9 3
7 .9 6
8.0 7
7 .9 9
8 .0 1
7 .9 6
7 .9 0
8 .0 0
8 .0 2
7 .95
8 .0 6
7 .9 2
536
540
524
515
536
545
526
539
530
520
535
525
531
548
492
526
533
524
535
*2
T3
Average
Average
Ta, T ,
1V 12 - L
555
560
550'
536
566
568
545
570
561
543
566
552
562
573
515
549
556
564
$60
549
555
551
530
564
$62
535
570
558
536
564
539
548
545
492
521
528
558
556
547
552
541
527
555
558
535
$60
550
533
555
535
547
555
300
532
539
549
550
"
552
557
551
533
565
565
540
570
360
540
563
545
555
559
504
535
542
361
558
# BO2
C onverted
to S
' 7 3.5
7 3 .0
62.2
4 1 .7
4 7 .1
67 .6
67 .0
67 .2
7 7 .5
60.6
69.5
6 3 .1
7 0 .7
66.5
3 3 .7
57.7
6 2.2
68 .7
62 .1
H rs . on
C a ta ly s t
3 .5
7 .0
10.5
1 4 .0
1 7 .5
2 1 .0
24.5
2 8 .0
3 1 .5
3 5 .0
3 8 .5
4 5 .5
4 9 .0
52.5
56 .0
59.5
6 3 .0
8 6 .0
115.5
% a
C onversion
(c o rre c te d )
7 3 .9
7 3 .8
6 3 .4
4 3 .3
4 9 .1
7 0 .0
69.9
7 0 .5
8 1 .2
64 .7
74 .0
68 .4
7 6 .4
7 2 .6
4 0 .2
64 .6
69.5
7 8.7
7 5.5
'T 1 , T2 , and T3 a re th e te m p e ra tu re s i r L 0C a t th e ■
t o p . m id d le, and bottom o f th e c a t a l y s t bed , r e s p e c tiv e ly .
2
See S e c tio n F, C a ta ly s t A c tiv ity , under D iscu ssio n o f R e s u lts , page 21.
i
w
■pi
TABLE H I
E f f e c t o f Feed R ate on S u lf u r Recovery
Moles SOg
• per h r.
Run No.
Ave. Temp.
0C.
Mole R a tio
CH4ZSO2
FR - I
544
3 .8 4
2 .0 4
FR - 2
554
3 .6 3
FR - 3
548
FR - 4
T o ta l
gram-moles
per h r.
% SOg
C onverted
to S
H rs . on
C a ta ly s t
% C onversion
(c o rre c te d )
9.86$
5 8 .4
68.5
66.4
2 .1 6
9.980
5 3 .4
7 1 .0
61.7
3 .1 8
1 .4 8
6.180
3 9 .6
7 5 .0
48 .2
551
3 .4 6
1 .3 6
6.060
15,3
7 8 .0
2 4.4
FR - 5
547
3 .7 8
2 .0 7
9.895
4 9 .6
8 0 .5
FR — 6
549
3 .4 8
1 .8 0
8.060
68.7
8 6 .0
78 .7
TB --13
■547
3 .6 8
1 .7 0
7.960
7 0 .7
4 9 .0
76 .4
-
59.0
TABLE H I I
E f f e c t o f Mole R a tio On S u lfu r Recovery
Run No,
Ave. Temp.
0C.
Mole R a tio
OH4ZSQ2
MR - I
546
4 .5 1
MR - 2
550
MR - 3
Moles SO2
per h r.
T o ta l
gram-moles
per h r.
* SOg
C onverted
to S
H rs . on
C a ta ly s t
% C onversion
(c o rre c te d )
1 .4 2
7 .9 5
5 5 .6
91.5
6 6 .2
2 .6 ?
2 .1 4
7 .8 5
4 7 .6
94 .0
58 .5
547
4 .8 6
1 .3 7
8.03
5 8 .6
96.5
69 .8
MR - 4
547
5 .19
1 .2 8
7 .9 4
5 2 .8
99 .0
64.3
MR - 5
546
2 .1 6
2 .4 8
7 .8 2
51.3
101.0
63 .0
MR - 6
545
3 .6 $
1 .7 2
7 .9 8 ,
5 8 .4
110.0
7 1 .2
MR - 7
553
2 .1 4
2 .49'
7.8 3
4 5 .2
112.5
58.3
MR - 8
550
3 .7 6
7 .9 2
6 2 .1
115.5
75.5
. 1 .6 6
TABLE IX
E f f e c t o f C a ta ly s t A c tiv ity on S u lf u r Recovery
Run Np.
Ave. Temp.
°C.
Mole R a tio
CH4ZSO2
Moles SO2
per h r.
T o ta l
gram-moles
per h r.
% SOp
C onverted
to S
H rs . on
C a ta ly s t
TB -
2
552
3 .6 ?
1 .7 1
7 .9 7
7 3 .0
7 .0
TB -
8
560
3 .7 5
1 .6 7
7 .%
67.2
2 8 .0
TB' -
9
550
3 .7 1
1.7 0
7 .9 6
7 7 .5
3 1 .5
TB - 11
555
3 .6 2
1 .7 3
7 .9 9
6 9 .5
3 8 .5
T B - 14
555
3 .8 2
1 .6 4
7 .9 0
66.5
52.5
FR -
6
549
3 .4 8
.1.80
8 .0 6
68.7
86.0
MR -
6
545
3 .6 5
1 .7 2
7 .9 8
5 8 .4
110.0
MR -
8
550
3 .7 6
1 .6 6
7 .9 2
6 2 .1
115.5
.
38
SULFUR
DIOXIDE
VENT
SUPPLY
METHANE
WATER
RECEI VER
SUPPLY
CATALYST
CONDENSER
CONSTANT
SULFUR
T EMP E RAT URE
CONDENSER
RECEIVER
FIG. I
BLOCK
FLOW DI AGRAM
Ol
CO
FIG 2
DIAGRAM
OF
S U L F UR
DIOXIDE REDUCTION UNIT
40
FEED
LINE
CAST
IRON PIPE CAP
MAGNESIA INSULATION
FROM CH4
MANOMETER
ALUNDUM
BALLS
FROM S O 2
MANOMETER
NICHROME
HEATI NG COILS
BAFFLE
CATALYST
BLACK IRON PI PE
THERMOWELL
STAI NLESS
SCREEN
THERMOCOUPLE
NOT
TO
- CONSTANT
TEMPERATURE
CONDENSER
LEADS
SCALE
FIG 3
S- TEEL
DIAGRAM
OF
REACTOR
41
CONDENSER
COOLANT
RESERVOIR
1 / 8 " PIPE
MAGNESIA
INSULATION
1/4" CERAMIC
BEAD PACKING
C OOLANT
NICHROME
HEATING COIL-
SCREEN
NOT
TO
FIG 4
PACklNG SUPPORT
SCALE
DI AGRAM
OF
CONSTANT-TEMPERATURE
CONDENSER
42
HOT
CONSTANT TEMPERATURE
CONDENSER-----------RUBBER
GASES
x----L INE TO
WATER
CONDENSER
CORK
SULFUR
-
fi \ \
GLASS WOOL
2-1/4"
GLASS
TUBE
x-'> —\ —\
GLASS
TUBE
HOT
GASES
ALUMINUM-FOIL CUP
SULFUR
RUBBER
NOT TO
SCALE
FIG
5
DIAGRAM
OF
S UL FU R
RECEIVER
CORK
43
DATA FROM TABLE 3
BED POSITION - INCHES TO BOTTOM
OF CATALYST BED
FIG 6 PERCENT YIELD VS BED POSITION
FIG 7
PERCENT YIELD
DATA FROM
60
VS
PREHEAT
TEMPERATURE
200
250
PREHEAT
300
TEMPERATURE
TABLE
IV
46
DATA FROM TABLE V
TEMPERATURE
FIG 8
"C
PERCENT YIELD VS TEMPERATURE
46
DATA FROM TABLE
T1 » 5 2 5 - 5 3 1
TEMPERATURE
ho 9
*C
PERCENT Y1Ei-D VS AVERAGE OF
T2 AND T3
47
DATA
FROM TABLE
Vl
T|= 333 -340
TEMPERATURE
FIG IO PERCENT
•C
YIELD VS AVERAGE OF T2 AND T3
40
DATA FROM TABLE
AVE. OF T0 AND T , ■ 8 6 7 - 6 6 6
TEMPERATURE
FIG Il
PERCENT Y I E L D
VS
• C
I
Vl
IOOi
DATA FROM
TABLE
Vl
K
*
20
0
-------------- --------------- --------------------------------------------- -—
BIO
520
530
540
550
560
TEMPERATURE eO
Fl G 12 PERCENT YIELD VS AVERAGE TEMPERATURE
QO
DATA FROM TABLE Vl
TEMPERATURE
FIG 13
PERCENT YIELD VS
•C
T2
51
TABLE
Vl
WT.
PERCENT
S ULF UR
DIOXIDE
DATA FROM
TEMPERATURE
\
FIG 14 PERCENT
YIELD VS AVERAGE OF T2 ANDT3
52
DATA
TOTAL
FIG 15
QM. - MOLES
PERCENT YIELD VS
PER
FROM
TABLE
HOUR
FEED RATE
%
Vll
53
DATA FROM TABLE Vlll
MOLE
FIG 16 PERCENT
RATIO
YIELD VS
MOL RATIO
PERCENT
SULFUR
m
P
DIOXIDE
MONTANA STATE UNIVERSITY LIBRARIES
CD
CO
CO
111 7I 62Ill l l 100
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B r y a n , J . D.
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