aspen modeling tristate icl
TRANSCRIPT
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CONTENTS
Page
ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . v
1 IN TRO D U CTIO N
. . . . . . . . . . . . . . . . . . . . . . . .
1
2
. D E S C R I P T I O N OF MODELS
. . . . . . . . . . . . . . . . . . .
6
2 . 1
L U R G I GASIFIER
. . . . . . . . . . . . . . . . . . . .
6
2 . 2 E N T R A I N E D G A S I F I E R . . . . . . . . . . . . . . . . . . 10
2 . 3
RAW-GAS COOLING
. . . . . . . . . . . . . . . . . . . . 14
2 . 4
I iECTLSO L MODEL . . . . . . . . . . . . . . . . . . . .
1.7
2 . 5 METHANOL SYNTHESIS . . . . . . . . . . . . . . . . . . 219
2 .6
MTG XODEL . . . . . . . . . . . . . . . . . . . . . . . 26
2 . 7 S H I F T / M E T H A N A T I O N S E C T I O N . . . . . . . . . . . . . . . 38
2.8 NAPHTHA HYDROTREATER
. . . . . . . . . . . . . . . . .
39
2 . 9 FORTRAN SUBROUTINES . . . . . . . . . . . . . . . . . . 4 3
3
.
IN TEG RA TIO N
OF
MODELS
. . . . . . . . . . . . . . . . . . .
45
4 .
R E S U L T S
. . . . . . . . . . . . . . . . . . . . . . . . . . 47
4 . 1
B A S E L I N E T R I - S T A T E CASE. . . . . . . . . . . . . . . .
47
4 . 2 Fuu-SLzE TRX-STATE CASE
. . . . . . . . . . . . . . .
55
4 . 3 T.LL1NOI.S NO . 6
FEED
. . . . . . . . . . . . . . . . . .
57
5. CO N CLU SIO N S
. . . . . . . . . . . . . . . . . . . . . . . .
59
6 . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . 6 2
7
.
A PPEN D IX : SA SO L COA L TE ST
DATA
. . . . . . . . . . . . . . 65
iii
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ACKNOWLEDGMENTS
The
a u t h o r s gratefully acknowledge the
s u p p o r t of
Morgantown
Energy
Technology
Cente r
f o r
t h i s work . The t e ch n i ca l gu idance
and
review
comments provided by Leonard E .
Grahatnn,
Chief of th e Process
Simula t ion and Analysis S e c t i o n ,
and
by h i s s t a f f w e r e h i g h l y c o n -
s t r u c t i v e
and
added measurably t o
t h e
final
results.
Yrogrammatic
guidance
by Ralph E . Schafer, Deputy
Director
of C o a l P r o j e c t s ,
Management Division,
was
i n v a l u a b l e a s t h e T r i - S t a te P r o j e c t
evolved
d u r i n g t h e course o f t h i s
work.
V
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ASPEN
MODELING OF
THE
TRT-STATE
NDIRECT
LI@~EEACTION
RBCESF
Ray E. Barker
John M. Regovich
James 11, C l i n t o n
P h i l i p
9 .
J01msc;an
ABSTRACT
The
ASPEN process s i m u l a t o r has been used t o model an
t n d i r e c t l i q u e f a c t i o n fl ow sh ee t p at t e rn e d a f t e r t h a t of the
T r i - S t a t e p r o j e c t . T h i s f l o ws h e et use s
Lurgi
mving-bed gas i -
f i c a t i o n wi th s y n t h e s i s gas c o n v e r s i o n
to
methanol followed by
f u r t h e r p ro ce ss in g t o g a s o l i n e using t h e Mob il MTG process.
N od el s d e ve lo p ed i n t h i s s t u d y i n c l u d e the fo l lowing: LurgI
g a s i f i e r , Texaco g a s i f i e r , s y n t h e s i s g a s
c.ooPing
.i Rect iso l . ,
me
hano
1
s y n t h e s i s m e thano
1-r
o-ga
s o l
i
ne
o
CO-s
h i
t
m e thana-
Eion,
a n d n a p h t h a h y d ro t r e a t i n g . Therje models
have
keen
successfully developed In modular
fo rm s o
t h a t t he y can be
used t o s imula te a
number of
d i f f e r e n t f l aw s h ee t s DT process
a l t e r n a t i v e s .
S i mu l a t i o n s of t h e T r i -S t a t e flowsheet have been made
u s i n g two d i f f e r e n t coa l
feed
ra tes and ~ W Q y p e s o f f e e d
c o a l .
The o v e r a l l
s i m u l a t i o n m ~ k l e lWAS a d j u s t e d
t o
match the
Tri-State
f l o w s h e e t v a l u e s
for
methano l , LBG, fsolautane, and
g a s o l i n e . A s a r e s u l t o f t h i s ad j us tm e n t, t h e MTC r e a c t o r
y i e l d structure n e c es s ar y t o
match
the f lowshee t product ra tes
w a s
de te rmined , Tfae models
were
e x e r c i s e d a t
dffferent
flow
ra tes
and
were
u n a f f e c t e d b y
such
c h a n g es , d e mo ns t ra t i ng t h e i r
range of
o p e r a b i l i t y . T h e
u s e of Lllinois Ma. ti
c o a l , w i th
i t s
lower ash c o n t e n t , resulted i n s l i g h t l y h i g h e r p ro du ct io n
ra tes of
each of t h e p r o d u ct s
a s
compared
t o u s e o f
t h e
Kentucky c o a l
1.
INTKODUCTION
The T r i - S t a t e P r o j e c t was o r i g i n a l l y c o n c e i v e d as
an
i n d i r e c t
F i s c h e r -Tro p s c h l i q u e fa c t i o n
p l a n t
produc ing approx imate ly 56,000 b a r r e l s
of
f u e l o i l e q u iv a l en t
p e r
day of t r a n s p o r t a t i o n f u e l s a nd c h em i ca ls from
Kentucky coa l .
The p r e l i m i n a r y d e s i g n of t h i s
plant
was co-funded by
the
Department o f Energy
(DOE)
and
t he
i n d u s t r i a l p a r t i c i p a n t s . W it hi n DOE,
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th e &rgantown Energy Technology
Centt?r (METC) has
t h e r o l e
of
t e c h n i c a l
l e a d
f o r
g a s i f i c a t i o n s ys te ms t o
ME-firnded
pr o j ec t s . In consonance wit11
t h e r o l e o n ' h i - S t a t e of providing Lechnological review and advice on
g a s i f i c a t i o n
a d
r e l a t e d sys t e ms
a
pr oc e s s
model
of t h e
o v e r a l l
p l a n t
would
(1)
e nh an ce t h e c a p a b i l i t i e s f o r i n v e s t i g a t i n g
and
e v a l u a t i n g
t c c h n i c a l
u n c e r z a i n t i e s
aid
a l t e r n a t i v e s a n d
( 2 )
provide
a
permanent
r e c o r d
f o r
f u t u r e r e f e re n c e
and
use .
Accurate p r o c e s s c a l c u l a t i o n s are n e c es s a ry f o r r a t i o n a l d e s i g n and
op era t i on of p roces s equipment, These c a lc u la t ions c a n r a nge from very
s i m p l e
( r e q u i r i n g
o n l y
a
poc ke t c a l c u l a to r ) t o ve r y complex ( r e qu i r i ng
a
la rge compute r ) .
I n
t h e l a t t e r case,
a
p ri ma ry t o o l i n u se a t ORlvL i s
t h e ASPEN (Advanced ys tem
€o r
r oc es s ng ine e r ing) p r oc e s s s imu la to r .
ASPLN i s a modern, s ta te-af- the-ar t process s imu la to r r e c e n t ly de ve lope d
f u r DOE ar a c o s t of 6 i n i l l i on . Th i s r e p o r t de t a i l s t h e model ing of a n
i n d i r e c t l i q u e f a c t i o n €1 owshee t us ing the ASPEN s imu la to r . These pro-
cess models have been developed i n modular form so th at they
can
be used
t o m 4 c l
a
:urnmbP?sr
of
d i f f e r e n t
process
a l t e r n a t i v e s .
T h i s work h a s c o n s i s t e d of developing models of t he va r ious sys t e ms
c ompri s ing the T r i - S ta t e p r o j e c z and in t e g r a t in g the models i n a con-
s i s t e n t
f a s h i o n
w i t h
recyc le
streams t o produce an ov er a l l p rocess model
u s i n g t h e ASPEN computer code.
Adequate
pr ope r ty da t a
of
l i qu id s ha ve
been obLainrd o r e s t ima te d a nd c o r re ' la e ed t o y i e ld t e c h n ic a l ly con-
s i s t e n t
medels
of
t h e
c r i t i c a l
areas
of th e pla nt . Although the
T r f - S t at e p r o j e c t h a s
been
te r mina te d , t he
ASPEN
models and sp ec ia l pur-
pose subrout ines deve loped for t h i s wcrk shou ld be a pp l i c a b le t o many
i n d i r e c t l i q u e f a c t i o n f lo w s h ee t s .
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3
S e v e r a l m o d i f i c a t i o n s t o t h e p r o j e c t and i t s f lowshee t
w e r e
made
dur ing th e des ign phase. The f lowshee t of the Tr i -S t a te p r o j ec t modeled
uses Lurg i moving-bed ga s i f i ca t i on and sy n t he s i s gas convers ion t o
methanol, which
i s
f u r t h e r p r o ce ss e d t o g a s o l i n e u s i n g t h e Mobil MTG
(methanol- to-gasol ine) process . Syn thes i s
gas
no t conver ted to methano l
i s me th a na te d t o prod u ce s u b s t i t u t e n a t u r a l g a s. A s i m p li f i e d o v e r a l l
f lowshee t of th e Lurgi-methanol-MTG p ro ce ss i s shown i n Fig.
1.
The western Kentucky coal i s f e d t o t h e c o n v e n t i o n a l d ry -a sh Lu rg i .
T h e L u r g i g a s i f i e r s are t o be modified
f o r
u s e w i t h c a k i ng
coals
by the
a d d i t i o n o f
a
s t i r r e r
t o
main tain good bed poro sfty . This arrangement
h a s b ee n t e s t e d w i th t h e p ro p os ed c o a l r e c e n t l y a t SAS0L.l The
L u r g i
g a s i f i c a t i o n model ha s b een c a l i b r a t e d t o r e f l e c t t h o s e t e s t r e s u l t s .
Th e s y n t h e s i s gas from the Lurgi
i s
cooled t o condense water and the
conden sable hydrocarbons. The
heat
r e l e a s e d f r o m t h i s c o o l i n g i s used
t o g e n er a te
l o w -
and medium-pressure steam.
The coo led syn th es i s gas
i s
t h en s e n t t o t h e R e c t i s o l p l a n t , w here
i t i s cooled and the H2S i s removed by absorption
i n
refrigerated metha-
nol . The R e c t i s o l f l o w s h e e t
i s a
s t a n d a r d d es i g n f o r
gases
c o n t a i n i n g
condensable hydrocarbons (i.e. naph tha) . The s u l f u r - f r e e g a s i s then
c ompres se d a nd p a s s e s t o t h e me th a no l s y n t h e s i s r e a c t o r .
The
methanol
s y n t h e s i s
process
u s e s t h e L u rg i r e a c t o r , w i t h t h e h e a t
of
r e a c t i o n
being
u se d t o g e n e r a t e
steam
i n t h e r e a c t o r j a c k e t . The r e a c t o r p ro d uc t
i s
cooled
t o
condense th e methanol, and th e unr eacte d gases
are
r e c y c l e d
t o t h e r e a c to r . I n or d e r t o pr e ve n t bu il du p of i n e r t s i n t h e r e a c t o r
recycle, I t
i s necessary to pu rge
a
p o r t i o n
of
t h a t stream, ca l l ed
t h e
purge gas .
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u
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The
u n i t s ulodeled i n t h i s s t u dy I n c h d e : Lurg i
gasi.Cler,
Texaco
( o r
o t h e r
e n t r a i n e d )
g a s i f i e r ,
s y n t h e s i s g as c o o l i n g , X e c t i s o l ,
methanol
sy n th es is , methamol-to-gasoliznf, CO-shift , methanation,
and
naphtha
hydrci t . rea t ing. A d d i t i o n a l l y , two user
FORTRAN
subroul:tnnes have been.
w r t t t e n f o r t h e d e v o l a t i l i z a t i o n of c oa l t o form char and v o l a t i l e pro-
d u c t s and fo r t h e d e c o mpo s i ti o a of coal.
t o
i t s
elements
p l u s a s h and
char . These rou t ine s
are
general.
and very i i s e f e r P i n
t h e
rztcsde'ling of
many
coal convers i .an processes .
Orie
user P O K T W - u n i t a p c ra t i o n mo d e l
h a s
been
written to f a c i l i t a t e m od elin g of waste h e a t : b o i l e r s ,
wMch a i e
wl.dely
used i n coal. convers ion
processes.
An
enhancemen t t o t h e ASPEN
p h y s i c a l p ro p e r t y s y s te m h a s a l s o been made t o a l lo w f o r t h e d i r e c t
i11put: of hea t of combust ion val ues fo r
c o d .
T h e
rernrairrder of
t h i s r e p o r t p r e s e n t s
(1)
t he de.ta. i .1~
f
t h e
u n i t
ope ra t ion models , FORTRAN
subrout j .nes
and ASPEN enhancement ; ( 2 1
how
t he se models were
t i i tegrated
t o a l l o w o v e r a l l mater ta l halances t o be
made; and ( 3 ) t h e r e s u l t s
u s i n g
d i f f e r e n t types
of feed
c o a l
and
v a r i a t i o n s
i n
coa l th roughpu t . The ASPEN computer i n p u t and r e p o r t
f i l e s f o r th e m0dels and
FBB IH.AN
s u b r o u t i n e s developed i n t h i s s tu dy are
b e l n g i s s u e d as a Suppleslent
t o
t h i s r e p or t . A l imited number
of
c o p i e s
a r e
a v a i l a b l e by c o n t a c t i n g ORNL. Micro f iche
c o p i e s
a r e available f r o m
the
N a t i o n a l Te c h n i c a l I n fo rma t i o n S e rv i c e (NTIS >.
2.
DESCRIPTION
OF MODELS
2 . 1 LURGI GASIFIER
The information necessary t o f o r m 1
a t e
the L u r g i g a a f f i e r model w a s
1 2
t a k e n
from
t h e SASOL c o a l t e s t and a r e l a t e d p u b l i c a t i o n . The model
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7
h as e s s e n t i a l l y f o u r s t e p s : (1) dryingldevolatilization;
( 2 )
convers ion
o f d e v o l a t i l i z e d coa l t o i t s e lemen ts , p l us ash and char;
3)
convers ion
of th e eleme nts t o produce gas-phase components; and
( 4 )
e q u i l i b r a t i o n
of th e gas-phase components. The e q u il i b r a te d gas-phase components
a r e t h e n r em ix ed w i th t h e v o l a t i l e s t o f o rm t h e raw s y n t h e s i s g a s .
The
s o l i d s f rom t h e g a s i f i e r are removed i n ano the r stream. The ASPEN
block
f low diagram for th i s model i s shown
i n
Fig.
2.
The c o a l d e v o l a t i l i z a t i o n
i s
d on e i n b l o ck
PROD
u s i n g t h e ASPEN
r e a c t o r mo d e l
KYIELD
w i t h u s e r y i e l d s u b r o u t i n e DEVOL. S u b r o u t h e DEVOL
c o n v e r t s h a l f
of
t he v o l a t i l e matter from the proximate analys is com-
p o n e n t a t t r i b u t e
t o
v o l a t l l e p ro d u c ts . The p ro d u c t s are assumed t o be
H2,
CH4,
R 0 , CO,
C,+, CO
a r e
p as se d t hr ou gh t h e f i r s t e i g h t l o c a t i o n s of t h e RFCAL vector i n t h e
ASPEN inpu t l anguage. These y i e l ds must
be
o b t a i n e d f ro m e mp i r i c a l
d e v o l a t i l i z a t i o n d a t a
o r from some
o t h e r s o u rc e . DEVOL u p d a t e s t h e
proximate and
u l t i m a t e
a n a l y s l s
of
t h e c o al t o
reElect
the changes due
t o d e v o l a t i l i z a t i o n ; i n t h i s m anner t h e e le me nt b al an c e
i s
maintained .
phenol , and t a r . Th e i r r e spec t ive y i e l d s
2
2’
A f t e r t h e v o l a t i l e s are removed i n t h e s e p a ra t i o n
block.
LBEVOL, t h e
d e v o l a t i l l z e d c o a l
i s
decomposed t o I t s e l e me n ts f n b l o ck C O W . Block
C OW also u s e s t h e ASPEN R Y I E L D r o u t i n e and a user y i e l d r o u t i n e ,
DECOMP. Subrou t ine DECOMP merely decomposes th e co a l t o i t s e lemen ts
p lus char and ash based on t h e u l t l m a t e a n a l y s i s . ‘Ilhis scheme places
t h e c o a l ( o r c h a r ) u n d er go in g g a s i f i c a t i o n i n t o c o n v e n t io n a l c om po nents
w h i l e s t i l l main ta in ing th e e lemen ta l ba lance .
The e lemen ta l coal c o n s t i t u e n t s
are
t h e n
m i x e d
w i th t h e g a s i f i e r
oxygen and
steam
f e e d s . I n block GAS1, t h e ASPEN
RSTOIC
model
i s
used
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ORNL DWG 82-1011R
COAL-FD
q
PRUDGAS
COALPROD
RGAS
REACTD I
OFFGAS
JACKTSTM
r
I
I
Q 1
Fig.
2 ,
ASPEN black
diagram
of L u r g i
gasifier model.
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10
2.2
EN I KAIINED
GASIFIER
The Texaco eiztrainetl g a s i f i e r model i s sirnil.ar to the TAurg imodel.
e x c e pt t h a t t h e e n t ra i -n e d g a s i f i e r a ssu mes t h a t d e v o l a t i l i z a t i o n i s
un impor tan t phis model h a s g i w n e x c e l l e n t r e s u l t s f o r m od elin g
entrained
g a s i f i e r s ;
T a h l e
shows
a
comparison between our model
pre-
d i ct i o n s arnd da ta
from
Koppers5 f o r t h r e e w id el y d i f f e r e n t c o a l s :
westerii , I l l i n o i s , and e a s t e r n c o a l s - F O P each coa l , th e ag reemen t
between
t h e
ASPEN p r e d i c t i o n s an d t h e
Koppers
data i s q u i t e g o a d ,
A n ASPEN block f l o w diagram of t h e e n tr a in e d g a s i f i e r
model.
for a
s o l i d coal f e e d
i s shown
i n Fig .
3. The
model beg ins by f i r s t decom-
p o s i n g a l l com pon en ts h av i ng a n u l .t ii na te a n a l y s i s a t t r t b u t e t o t h e i r
e l e me n t s , p l u s ash and char . T h is d e c o ~ ~ ~ p o s i t f ~ ~ ~
s
done
i n
b lock CONV
u s i n g
tlrcs
user y i e l d s u b r o u t i n e , DECBMP, as d e s cr i b ed i n t h e p r e v io u s
d i s cus s io n o f th e Lurg i model. IF n ot o t h e r w i s e s p e c i f i e d , t h e carbon
burnup
i.s
assumed t o be
100%.
It s h o u l d b e n o t e d t h a t DECOMP will a l s o
decompose a t t r i b u t e c o n v e n t i o n a l co mp on en ts , s u c h as t a r . When a s o l i d
coal. feed i s
not
used , as i n the
T r i - S t a t e
case, t h e ASPEN
flow
diagram
shown i n Fig .
4 i s
used.
The
conver ted e lemen ts a r e t h e n m f x ed w i t h t h e
oxygen and t h e s o l i d phases r e a c t e d t o gas-phasi? c o m p ~ n e n t ~nd adia-
b a t i c a l l y e q u i l i b r a t e d
as
in the Lurgi model . The h o t , e q u i l i b r a t e d
gases
are then quenched w i t h
water
t o a temperature of 1800'F;
a de s ign
s p e c i f i c a t i o n
i s
i n c l u d e d t o v a ry
the
quench water f low r a t e t o o b t a i n
t h e s p e c i f i e d o u t l e t t em p er at ur e.
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11
Table
1.
Comparison
of ASPEN
entrained g as if ie r model and published reports
of
Koppers-
T ot zek g a s i f i e r p e r f o m n e e (basfs: 1 t o n / h )
Analysis , w t X
C
H
N
s
0
Ash
Moisture
Gross heating value
( B tu / l b )
Oxygen
(98% 0 2 >
( l b l h )
Steam (250 F, 14.7 p s i )
( I b l h )
INPUT
Coal
Western
56,76
4.24
1.01
0.67
13.18
22.14
2.00
I l l i n o i s
61.94
4.36
0.97
4.88
6.73
19.12
2.00
Eastern
-___.
69.88
4.90
1.37
1.08
7.05
13.72
2.
oa
9,888
11,388
12,696
1,298 1,408
1 , 634
272.9 541.3 587 .4
RE sULT
ASPEN Koppers
ASPEN
Koppers ASPEN Koppers
-~
Gas production (SCFH)
5 1 665
51,783 57,752 59,489 64,473
65,376
Gas compositfon,
m o l X
( d r y )
33,3 32.86
35.0 34.62
35.7 35.39
59.5 58 .68 55.4
55.38 56.0 55. Y O
5-81
7.04 6.7
7.04
6.88 7. 18
1.07
1.12 0.98
1.01
1.11 1.14
0.27 0.28
1.80 1.83
0.36 0.35
0.02
0.02
a. 09 0.12
0.02 0.04
Carbon burnup, w t X
-
assumed
1
99.5 97. 0 -
97.0
-
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1 2
I
I
I
I
I
I
I
I
I
-
I
1.
w
Fig.
3 .
a solid
coal f
COOLASH
ASPEN
eed.
GAS
BFWl
block diagram of
e n t r a i n e d
g a s i f i e r
model
w i t h
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13
ORNL DWG
82-1451R
TSTEAM TOXYGEN
TLIQ5UT
WATER
TSTEAM
PROPUCT
Fig.
4 .
ASPEN
block diagram of e n t r a i n e d
gasifier w d e l
w i t h
l i q u i d f e e ds .
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2.3
RAW-GAS
COOLING
The
Tr-t -S ta te
f lowshee t c a l l s f o r t h e r a w synthes j is gas t o he
c o o l e d and s e n t t o R e c t i s o l , n o t u s i n g
a
r a w s h i f t as i n some other
p roposed p rocesses . ‘l’he se ns ib le hea t i n ho t raw s y n t h e s i s g as i s a
s i g n i f i c a n t f r a c t i o n of t h e h e a t i n g v a l ue of t h e f ee d c o a l a nd , t h e r e -
f o r e , must b e r e c o v e re d e f f i c i e n t l y . This recovery p rocess ts the func-
t i o n of th e raw-gas coo l ing sec t io n .
The
process f low diagram used
f o r
our gas cooking model
i s
shown i n
6
Fig .
5.
Th e d e t a i l s
of
t h i s f l o w s h e e t
w e r e
t aken f rom
Wham
e t a:
The gas c o o l in g s e c t f o n c o o ls t h e raw synthesis g as t o t h e lowest prac-
t i c a l t e mp e ra t u re u s i n g
water
and
a i r
coo l ing , This maximum practical
c o o l i n g re du ce s t h e r e f r i g e r a t i o n r eq u ir em e nt s i n t h e R e c t i s o l u n i t
which fo l lows.
The ASPEN block flow diagram f o r th e gas-cool ing model i s shown i n
Fig . 6 . The ho t s yn th es i s gas i s first scrubbed wPth recycle condensate ,
b lock M1
The
tw o-ph ase d x t u r e from t h e s c ru b b e r i s co oled i n th e f i r s t
he a t exchanger , b lock
E 3 0 1 E 3 ,
generating medium-pressure steam. The gas
f ro m t h e f i r s t h e a t e xc ha ng er i s
f e d t o
a knockout drum, with t he con-
d e n s a t e r e c y c l e d t o the sc rubber . The
gas
from the knockout drum
i s
c o o l ed fu r t h e r i n t h e s e co nd h e a t e x c ha n g er , b l oc k E 3 0 3 A E 1 , producing
more
medium-pressure steam and d i r ty condensa te. ‘ h e gas i s t h e n f e d t o
t h e t h i r d h e a t e xc ha ng er
t o
produce low-pressure
steam.
A t
t h i s
p o i n t ,
t h e g a s s t r ea m
i s
a i r -cooled
and
water-cooled and se nt 60 t h e R e c t i s o l
u n i t .
This
model assumes a c l e a n t a r /wa te r separation i n b lo ck SWPLIT,
w i t h t h e t a r being f e d
t o
t h e
Texaco
gasifier. R e Redlich-bong-Soave
(SYSOP3) equat ion , which i s e x c e l le n t f o r l i g h t gases and hydrocarbons ,
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i s used f o r t h e c a l c u l a t i o n
of
p h y s i c a l p r o p e r t i e s f o r p r o c e s s
streams;
t h e ASME
steam
t a b l e c o r r e l a t io n s SYSOP12) are used for
steam
and
c o o l i n g water. Tbe p h y s i c a l p r o p e r t i e s for the condensable hydrocarbons
w e r e o b t a i n e d u s i n g t h e
Wilson
co rr e l a t io n. When a r f go r ous ASPEN
sour-water
f la sh mde l has been developed,
I t
should r e p f a c e the p r e s e n t
FLASH2 blocks.
3
2.4 RECTISOL ESODEL
T h e c a t a l y s t s
u s e d
f o r me th an o l s y n t h e s i s
and
methanat ion
are
sen-
s i t i v e
t o
poisoning
by
s u l f u r
C O I U ~ Q U ~ ~ S ,
he
R e e t i so l
process i s
one
of
t h e more
w f d e k y
used p rocesse s
f o r
removing
H S from
s y n t h e s i s gas. "he
R e c t i s o l p r o c e s s uses methanol
as
a s o l v e n t
f o r
the H , S a
A t
the tempera-
t u r e s used (-70"F), H,
S
i s
more scslub1.e
i n
methanol
than are
t h e o t h e r
major
components
of
s y n t h e s i s
gaso The flowsheet
used he re
I s
t h e s t a n -
dard f ive-column process
designed f o r
t r e a t i n g g a s es c o n t a in i n g
a
s i g n i f i -
c a n t c o n c e n t r a t i o n of naphtha , The presence
of
naph tha compl i ca t e s t he
p r o c e s s i n g b e ca u se an azeo t rope i s f~rmedlbetween naphtha
and methanol
and two l i q u i d p ha s es c a n be formed i n the naph tha /me thano l/wa te r
system. To prov ide
f o r
t h e s e h i g h l y n o n i d e a l v a p o r - l i qu i d
equilibria,
t h e v e r s i o n
of
t h e Soave-Redlich-Kwong eq ua ti on
of
s t a t e t h a t
has
been
modi f i ed for polar components (Redlich-bong-ASPEN) was u s e d . F i t t e d
b i n a r y i n t e r a c t i o n p ar a me te r s
are
u s e d f o r
a l l
i n t e r a c t i n g s p e c i e s .
The
data
shown
i n
the
ASPEN
i n p u t
file
are
i d e n t i c a l t o t h e
RKSKIJ
i n s e r t
u s e d
i n the
gasifier s e c t i o n .
2
2
4
The process flow diagram f o r the Rec t i so l model i s shown i n Fig. 7.
The c or re sp on di ng ASPEN block diagram
i s
shown i n Fig,
8,
"he
r a w
gas
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_
_
_
_
_
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RECMXG
RREFRIGl
HEATER
RECDESC.2
RECVAP 13
REC.WG3
RECGLIQ
LASri3
REiGbI92
SC
1
RECAZEO
HXDL'TP3
I
L,
P I 7
R E C L i Q i 7
I
RECNAPEF
REC SAP
15
HECH
RHZOWASH
RHZOWCV
PADFRC RADFRC
RECOFFG
4
RECHZOEF
kECMStiR3
I
Fig. 8. ASPEN
block
diagram
of
Rectissl section.
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20
from gas c oa l ing i s exchanged against
the
purified gas and
w P t h
makeup
r e f r l g e r a t i o n
and
f e d t o the prewash se c t io n of t h e
absorber.
The
prewash
i s o p e ra t e d
SQ t h a t
t h e naphtha i s
absorbed
whlbe allowing
t he
l i g h t e r components t o pa ss t o
t b e upper
s e c t i o n
s E the absorber. The
loaded
soPvent
i s se n t t o t he a z e o t r ope c olumn t o
separa te
a
c lean
naphtha product and a methanol-r ich
stream.
The loaded so lvent
from “ t ~ s
u p p e r
s e c t i o n
of
the
absorber i s f l as h e d t o release a bso r be d syn the s i s
gas (w:iich i s
r e c y c l e d t o
t h e
absorber
i n l e t ) and then f e d t o t h e
s t r i p p e r a l o ng w i t h the methanol-r lch
stream
f rom the aze~trope olumn.
In
t h e
stripper
t h e
H r S
is s t ~ i p p e d . n m
the
solvent-
forming
a
H
S-rich
vapor stream. The 3 , s - r i c h stream i s washcd with
water
t o rzcover t h e
meehanol. The water-methanol mixture i s
t hen
d i s t i l l e d t o ob ta i i l a l e a n
methanol stream
for
r ecy e l c to
the
absorber .
‘ R e bottom s t r e m from
t h e
H ~ S t r i p p ~ rs a l s o
recycleel t o t h e
absorber ,
2 7
E
2. S P I E T W Q L SYNTHESIS
The methanol synthes is model i s based on t h e 14urgh tubular
reactor
6 , 8 - - 1 1
concept . In
that
scheme,
t h e
h e a t
s f
r e a c t i o n
i s
u s e d t o
wake
steam I n t h e r e a c t o r shell, which
i s
t he n
available
f o r
use
e l sewhe re in
t h e process. rtao m et ha no l s y n t h e s i s r e a c t i o n s are assumed t o
occur
and
t o be a t
e qu i l i b r ium
a t
the
reactor exit:
CO
+
2R2 8 11-I OH
CO, 4- 3s2 *
C H p
, 3
1120
The f lowshe e t d e t a i l s have been taken f rom Wham e t a1.6
The
f lowshee t
compressed a n d d x e d w i t h the recyc le . The mbxtrsre of fresh feed and
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z
re
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22
recyc1.e i s then compressed t o t h e d e s i r e d r e a c t i o n p r e s s u re . TE-IPS
stream i s heated by heat exchange w i t h r e a c t o r e f f l u e n t before e n t e r i n g
t h e r e a c t o r . A f t e r heat exchange with the r e a c t o r f e e d , t h e r e a c t o r
e f f l u e n t i s coo led . fu r ther
i n
air- and water-cooled exchangers t o con-
dense the prod1xc.t methanol. The noncondensalzles are s p l i t part
r e c y c l e d , a n d the rest purged t o p r e v e n t hi . l .&ap of i n e r t s s uc h as
methane and h igher hydrocarbons i n t h e r e a c t o r l o o p , The purge gas
i s
s e n t t o
the s h i f
t / m e t h a n a t i ~ o n
i n i t
f o r f u r t h er
processing. The methanol
pi:odiict
i s
f u r t h e r d e p r e s s u r i z e d v a p o r i z i n g a d d i t i o n a l l i g h t g a s w hic h
can be
w e d as
fuel .
o r
sen t
to methanat ion .
Part
of
the
steam
g e n e r a t e d
i n
the
r e a c t o r j a c k e t i s expanded through a t u r b i n e
t o
g e n e r a t e
the
p m m r
n e c e s s a ry t o w n t h e f e e d a nd r e c y c l e c omp re ss or s.
T h e ASPEN block diagram f o r t h e methanol s y nt he si s simulacj.on -Is
shown io. Fig. 10.
he
si.mul.ation u s e s
t h e ASPEN
COMPR
block t o s i m -
l a t e t h e two
compressors
and
thtt:
t u r b i n e , ASPEN BEATER b lo ck s have been
u s e d t o s i m r r l a t e t h e h e a t e x c h a n g e r s , w i t h the two s ides of t h e
f ee d / e f f i ue n t exchanger connected
by
a beat i n f o r m a t i o n
stream, Q1.
r e a c t o r i s
modeled by an ASPEN REQUXL b lock and
i s
assu med t o o p e ra t e
i s o t h e r m a l l y . The
heat
of reactf-on
f rom
the reactor i s passed
t o
the
b o i l . e r
user model v ia heat :
stream
42.
'The steam. produced
i n t h e
b o i l e r
i s s p l i t , w i t h p a r t o f t h e steam sent t o t h e t u r b i n e . Tlie t u rb i n e b l o c k
The
accepts t h e work i t ~ f o r r n a t i o n
treams
f rom the @ompj:&SsoTS,
W1 and
W2,
a n d c a l c u l a t e s a n "excess" work i n f o r m a t i o n stream, W3. An ASPEN DESIGN-
SPEC va r i e s t h e s p l i t
u f t h e
steam
s t ream
so t ha t t h e e x c e s s work from
t h e t u r b in e
i s
zero. The produc t
condensation
and l e t d o w n o p e r a t i o n s arc
s i m u l a t e d
w i t h
the ASPEN FLASH2 bl0c.k. The f i t t e d b l n a ry i n t e r a c t - i o n
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2 3
PUREGAS
w2
I ?
? iLTKECYA
M L I K t I
I
I
JJ
ETNIXER METRECYC
MIXER
H i A l I R
I
HETCOOLR w r w
E TcDND
HEATER
FLASH2
Fig. 20
ASPEN block
diagram
of the methanal synt.hesis
s e c t i o n .
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24
c o n s t a n t s disci . issed i n rhe Re ct i so l model are used Tor the v a p o r - l i q u i d
equi
l l b r i u m c a l c u l a t i o n s .
T h e
methanol synthesis
model
has
Four
primary
i n d e p e n d e n t v a r i a b l e s
:
( 1 )
feed composi t ion and s t a t e , ( 2 )
reactor
t e mp e ra t u re , (3) r e a c t o r
p r e s s u r e , and ( 4 )
r ecy c l e
ratio. Other v a r i a b l e s , u s u a l l y c o n si d e re d
constant ( e . g . , pressure d r o p s through the equipment , tem peratur e and
p r e s s u r e of t he
product
sepa r a to r s , steam p r e s s u r e ,
e r e . ) , can
a l s o be
v a r i e d .
Tab le 2 shows t h e r e s u l t s of v a ry i n g t h e
reactor
p r e s s u r e
and
r ecyc le r a t i o , h o l d i n g the s y n t h e s i s temperature constant (500°F)
and
u s i n g t h e f e e d eonposition. from t h e Tr f -S t a t e design r e p o r t . l 2 m e
cornposittoen
and
c o n d i t i o n s are shown
i n
Tab le 3.
The
r e s u l t s i n
Table
2
i n d i c a t e
t h a t
u s i n g recyc le r a z i o s g r e a t e r t h a n a b o u t 1.0 i n c r e a s e s t h e
equipment
s i z e
and comprt:..ssor horsepower,
with
l i t I e increase i n metha-
n o l product ion. I n t h e case
of
T r i - S t a t e , where t h e purge
gas
i s to be
s h i f t e d and m t h a n a t e d
t o
produce
SNG
(assuming
t h a t
t h e
SNG
can
be
s o l d ) ,
the re
i s 1it:tIe inc ent €ve t o use a recycle ratio g r e a t e r than 1.0.
Table
3 ,
Synthcs-bs gas f e e d t o
methanol s y n t h e s i s m o d e l
Cornpocent
Plow
rate
1
-mol/h
1
H
C 6
c02
C B
H20
CH
C ;
Ci30K
N
Feed
t empera tu re
Feed p ressu re
57 , 2 4 1
1 ,528
28,630
13 , 5 9 4
388
92
541
0
0
100°F
508 p s i a
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2 6
2 , 4
MTG
MODEJ.,
The b a s i s f o r p ro d u ci n g g a s o l i n e
from synthesis
gas v i a
methanol
i s
t h e Mobil methanol- to-gasol ine
(MTG)
p ro c e s s - T n i s p r o p r l e t a r y p r o c e s s
u s e s a z e o l i t e c a t a l y s t t o c on ve rt m.tljPai101 to l igh t 1 . iqu i .d fue l s
( l i g h t e r t ha n
about
C ) and some l i g h t , gases. Because of t h e
p r o p r i e t a r y n a t u r e of
Che ~ P O C ~ R R , ery 1 i t t l . e i s
known about
the
MTG
s y a t h e s i s r e a c to r i t s e l f . A produc t yPe1.d s t r u c t u r e
f o r
t h e r e a c t o r
was
taken from Schreitner. Other process d e t a i l s
were
t aken from b m nd
Lee
and
from
S d o v e r .
1 0
9
1 3 1 1
The process f l o w d iagram used fo r the s imu la t ion o f the MTG, f r a c -
t i o n a t l o n , and a .l k y l ac fo n s e c t i o n
i s showr, i n
P ig .
11.
The f e e d t o
t h e u n i t i s h e a t e d a g a i n s t t h e
reac tor
e f f l u e n t , m i x e d
w i t h
Light,-gas
r e c y c l e , and f e d t o t h e r e a c t o r . The r e a c t o r i s assunzed t o be
t h e
Luxgi . - tubular typep
and
t h e h e a t
of
r e a c t i o n i s used t o g e n e ra t e
steam.
T h e r e a c t o r e f f l u e n t i s coo led t o p roduce a
three.-p'taase mixtinre
of gaso-
l i n e , w 2 te r , and l i g h t
gases:
(1) t h e gases are
recycled
t o t h e r e a c t o r ;
( 2 ) the water i s
s e n t t o was tewate r t rea tmen t ; and 3 )
the
g a s o l i n e i s
sent t o t h e g a s o l i n e f r a c t i o n a t i o n s ec t do n .
T h e f r a c t i o n a t i o n s e c t i o n I s of
t he
st an da rd two-column des ig n,
producing l i g h t
gases (C2 - j ,
a
stabillzed gasc,l.ine
C5 - t - ) , and a n a l k p l a -
t i o n f e e d e3.
w t t h o u t
f u r t h e r t r e a t m e n t .
'l"ne
a l k y l a t i o n f e e d
i s
mixed
w i t h
t h e i s o b u -
t a n g
r e c y c l e stream and f e d t o th e a lkg7latPon
reactor .
The alkylat : i .on
s t e p reac ts u n s a t u ra t e s w i t h Ls o al k an e s t o
produce
h igh-oc tane gaso l ine
by
t h e r e a c t i o n s :
Il r\e g a s o l i n e can be
s en t
t o gaso?.ine b l e n d i n g
5
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28
c B +
i-B:
M
+
3 6 4
1 0
C7H1
s
C,,H8
-f-
i-c
I I
+.
c 1
‘c
1 0
8
1 8
I-
i -c
1-7
c
K
0 ‘4 1 0 9
2 0
1.
1
Tt
i s c o rn o n p ra c t i c e t o r e c y c l e l a r g e amounts
p o l y me r i z a t i o n a nd t o e n s u re
complete
c o n v e r s i o n
of i s sbs l t ane t o p re v e n t
of t h e u n s a t u ra t e s .
The
a l k y l a t i o n p ro d u c t 9s s e n t
t o a
two-column f r a c t i o n a t i o n system t o
recover the unreacted isobutasie f o r r ecyc le , t h c a l k y l a t e f o r g a s ol i ne
b lend ing , as well as
C 3
and (21,
product
sL;r%ams.
The
ASPEN block diagram f a r t h i s s i r n i l a t i o n i s shown i n
Ffg.
12.
The o v e r a l l s e c t i o n c o n t -a i m r e a c t o r s , h e a t exchangers, and d i s t i l l a t i o n
columns.
The Grayson-S t reed co r re la t ion
(SPSOPZ)
i s
used
f o r vapor-
l i q u i d e q i i l l i h r ia c a l c u l a t lo n s . Gragson-Streed i s adequa te
f o r
t h i s
uni t :
s ince
the compounds
haadlied
a re
p r t m r i l y
l i g h t l i q u i d hydrocarbons .
The ASPEN r e a c t o r model RYIELD i s used t o s i m ul a te the MTG s y n t h e s i s
r e a c t o r , based on yield data froisn
Schreiner .
e q u i l i b r i u m
reactor
model could no t be
used
because the ac tu a l re ac t io ns have not been
p u b l is h e d ; i n
addition,
a s h a p e - s e l e c t i v e z e o l i t e catalyst
which
skews
t h e product slate has been used i n t h e process.
The
R Y I E L D model quan-
t i t a t i v e l y c o n ve rt s t h e f ee d methanol t o g a so l in e and l i g h t e r p r o d uc t s
u s i n g the f i n a l p ro du ct d i s t r i b u t i o n as pub l i shed
by
Hobil. A s e r i o u s
l i m i t a t i o n of t h i s model i s that t h e reactor
is
based on a s i n g l e
p r u d u c t d i s t r i b u t i o n ,
obtlalned
a t Mo b i l ‘ s “ p re f e r r e d “ o p e r a t i n g
c o n d i t i o n s . Therefore, v a r y i n g r e a c t o r tempesattnre a n d p re s s u re may
g i v e
e r r ~ n e o u f i
results.
The
modcl
is a d eq u at e f o r e a l c u l a t i n g heat
d u t l e s p r o d u c t r e c o v e r i e s ,
etc .
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31
MTGGASBL
F i g . 1 3 . ASPEN block f low
diagram
of
fractionation
s e c t i o n .
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3 2
O N , WG 8 2 - l 4 5 2 R
M G C 3
IBUTRECL
GASPROD
MIXER
TGGASBL
GAS
LPGPRBD
HIXER
l
P i g .
14 .
ASPEN bl.ock diagram of alkylation sec t ion .
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O A N L
DWG
82-12898
N m n T n A
HYDROTREATER
PRESSOR
60 N
DENSATE
METHANOL OFF-GAS
Fig .
'15.
Process f l a w diagram
of methanatton
s ec t i o n .
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35
u n i t . In t h e me th a n at io n u n i t , 6 8 , C82 , CII30H, and
w i t h hydrogen t o form CH4 and water in t w o r e a c t o r s
eo -t- 3112 f C l t 4 f B20
C2Rg + H 2 8 26H,
CH30W f H2
CMq
-4- H2Q
coz
+
4a, f CBq -4-
2H20
The f i r s t r e a c t o r reacts most of t h e 60 ,
CR301-2,
and
C ~ R P J are r e a c t e d
as fo l lows :
C2Rg wit h hydrogen,
a nd t h e s e co nd r e a c t o r e s s e n t f a l l y c o m p le te s t h e s e r e a c t i o n s a nd r e a c t s
C O 2 w i t h the remaining hydrogen, In bo th th e sh iE t and the methanat ion
se c t io ns condensers remove
water
f rom
the
r e a c t o r e f f l u e n t
The ASPEN
block
f lo w dia gr am f o r t h e s h i f t u n i t s i m u l a ti o n
1s shown
i n Fig .
17.
The purge gas from th e methanol sy nt he s i s
ks
s p l i t b etw ee n
t h e s h i f t a r e a and t h e m t h a n a t i o n area, A s p l i t of
35 t~
t h e
shift
u n i t has been assumed f o r t h i s s t ag e of deve lopmen t
of
t h e d e t a i l e d
models . The amount of gas se n t t o th e s h i f t area w i l l depend on
how
much hydrogen
i s
needed
and
will
be
de te rmined concurren t wi th the
o v e r a l l p l an t mass balance. The g as t o t h e s h i f t u n i t i s heat exchanged
w i th r e a c t o r e f f l u e n t us tng ASPEN h e a t
streams.
The gas i s then mixed
w i t h steam v i a a FORTRAN d e s i g n s t a t e me n t t o ach ieve
a
WpO-to-CO r a t i o
o f 3:1 . The steam-gas mixture i s r e ac t ed i n
an
a d i a b a t i c REQUIL r e a c t o r
t o a c h i e v e t h e
CO
and
H 2 0
c o nv e rs io n t o
H2
and C 0 2 .
The r e a c t o r e f f l u e n t 1s hea t exchanged wi t h th e reactor f e e d I n
HEATER block. The r e a c to r e f f l u e n t i s c o o l e d f u r t h e r by heat exchange
w i t h b o i l e r f e ed
w a t e r
t o p ro d uc e
steam.
The u s e r s u b r o u t i n e BOILER
d e t e rmi n e s how much bo i l e r f eed water
i s
r e q u i r e d t o p ro d u c e s a t u r a t e d
steam a t
a
given pres sure . The gas i s c oo le d f u r t h e r i n a ser ies of
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t
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d
H
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b l o c k ; a
FLASH3
ASPEN block i s used as a condenser , and on ly
the
o rg a n i c
phase i s r e f l u x e d a f t e r b ei n g h ea t e d
by a
HEATER
block.
The
h y d ro t r e a t e d n a p h t h a
w a s given
a
mo l e c u l a r
weigh :
o f
S c hr e ine r , bu t no molecu la r welght w a s a s si g n ed t o t h e g a s i f i e r naphtha,
I n
t h i s s t u d y , a molecular weight of
100 was
ass igned t o t he
gasifier
naph tha and mzy bc ad jus ted i f
more
informatfon i s obta ined.
The
g a s i f i e r n a p ht ha a nd h y d r o t r e a t e d
napb tha
are e n t e r e d
as
user-def-ined
components. E x c e p t f o r t h e m o l ec u la r w e ig h t, t h e p h y s i c a l p r o p e r t i e s
a r e those of to luene bu t may b e a d j u s t e d
as
f u r t h e r in format ion dfc-.
t n t e s , The b.dlfeh-)i(wong-Soave
equa t ion o f
s t a t e
w a s used for vapor:
l i q u i d e q u l l i b r i u m a nd e n t h a l p y
calcul at
ons
I n t h e course of d e v e l o p i n g t h e ASPEN s i m u l a t i o n s ,
%t
was found
n e c e s s a ry (or conveniiE.nt 1
to
w r i t e .
some
~~~~~~ subroutines to perform
some
simple,
r e p e t i t i v e
tasks
and
to
enhance
the
f l e x i b i l i t y and
utility
of the models.
Two
of these subroutines i.zser--yiel.d r o u t i n e s DE'UOJ,
and
IDECOMP,
were
descr ibed
in
t h e Lurg l
gas j - f i e r
section, The gasifiers
also call three oth-er user S U ~ ~ O U ~ Z R ~ Sdeveloped hy a p r e v f o u s s t u d y
1:
(1) ENYHLU,
Salrnic,h
c a l c u l a t e s
t he
e n t h a l p y
of ash a t
any t e m p e r a t u r e ;
( 2 )
ASH.I l ,
w hi ch c a l c u l a t e s the e n t h a l p y of a s h s o l i d s a t a g i v e n tern-
p e r a t u r e , and (3) S
which ca lcu la t e s the
average mohecular weighl:
of a stream. U se r u n i t o p e r a t i o n s u b r o u t i n e B O I L E R a n the enhancements
t o the
coal enthalpy
model
~ C O ~ X ~ ~ ~ ~
re
d i s c u s s e d
in this
section.
4
Ma i n t a i n i n g a n a c c u r a t e steam ba lance I s very impor tan t if
usefiml.
s i m u l a t i o n s are to be produced,
User
un i t ope ra t i on model
BOILER
was
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4 5
th e new su bro u t in e ENT445. S u b ro u t i n e ENT445 merely obtains
the heat
of
combust ion from t h e
component
a t t r i b u t e v e c to r , c o nv e rt s th e u n i t s t o
S I , a n d r e t u rn s the v a l u e t o ENTBCC.
3.
INTEGRATION
OF
MODELS
A s
can be s ee n i n
Fig.
I , most of the uni% o p e r a t i o n s present i n
t h e T r l - S t a t e p r o j e c t f l o w sh e e t h av e been rmdeled u s fn g ASPEN. [Unit
o p e r a t i o n s n o t modelea i n c l u d e head-end process ing s teps ; (such
as
coal
p r e p a r a t i o n a n d the oxygen and steam p l a n t s ) a n d c leanup p ro c e s s e s (such
as ammonia and
s i l l f u r
r e c o v e r y . ) ?
m a t e r i a l and energy ba lances ,
i t
would now be des-irable t o c o u p l e
a p p r o p r i a t e l y a11 of the deve loped models in t o a s d n g l e simi-ilation,
P l a n t o u t p u t streams could t h e n
be
checked f o r v a r i o u s
input
feed and
i n t e r n a l p r o ce s s c o n d i ti o n s
e In t h i s w a y
t h e
process
eff c i e n c y a n d / o r
produc t s l a t e d e s i r e d c o u l d
be
op t imized f o r
a
particular coa l and
o v e r a l l
E l c l w s l i e e t
e
In o r d e r t o per fo rm o v e r a l l plant
The coupl ing of a l l of
these
ASPEN models
i n t o a s h a l e s3mula t ion
program y i e l ds , however ,
a
computer program
chat
is qui te ccmplcx and
o n e t h a t requfres a
co n s l d e rab l e
amount of
care. Th ls
problem has been
circumvented by d i v id i n g t h e o v e r a l l flowsheet dnto suhsets, *9s shown
i n Fig. 21, the v a r i o u s ASPEN m o d e l s have been combinied i n t o flvc
m j o r
groups: 1) h r g i gasifter, gas cool ing, g a s - l i q u o r s e p a r a t i o n ,
arid
T e x a c o g a s i f i e r ;
( 2 )
k c t i s o l ; ( 3 ) raet l ianol synthes is W - s k l f t , metha-
nation, and
SNG
p u r i f i c a t l o n ; ( 4 ) naphtha h y d r o t r e a t e r ; and (5) 'I.lohPE
MTG, f r a c t i o n a t i o n , a l k y l a t i o n , and gasoline b lend ing . S e q u e n t g a l ex@-
c u t i o n
of these
major groups s h o u l d a l l o w
a v e ra l l
p l a n t balances
t o
he
achieved
i n
e s s e n t i a l l y
a
s i n g l e
p a s s .
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47
4 .
SULTS
The f i n a l T r i -S t a c e S y n fu e l s P ro j e c t b l oc k
f l o w
d i a g r a m , e n t i t l e d
**case
3
-
coal
t o G a so l in e
-
% a r t c r Size
Plant , ' "12
w a s
used
as
t h e
b a s e l i n e T r i - S t a t e case f o r
checkfng
the deve loped
ASPEN
models I n an
o v e r a l l s h n i la t i o n p e r f o m e d
by
s e q u e n t i a l e x e c u t i o n of t h e ma jo r
groups . To d e mo n s t r a t e t h e
range
of
o p e r a b i l i t y of these models ,
overall
s i mu l a t i o n s were also performed
us ing
feed of I l l i n o i s No. 6
c o a l a nd t h e o r i g i n a l f u l l - s c a l e f e e d r a t e
rsf
Kentucky No. 9 c o a l to t he
I:
l a n t.
4.1 BASELlNE TRI-STATE CASE
I n the b a s e l i n e Tri-State case, 240 trans/h
of
Kentucky No. 9 coal
w ou ld b e c o n v er t e d t o t r a n s p o r t a t i o n f u e l s and chemicals e The chemical
a nd p h y s ic a l c h a r a c t e r i s t i c s of t h i s coal are g i v e n in Tab le 4. It
s h o u l d
be
no ted
t h a t
the hydrogen and oxygen v a lu e s l i s t e d i n Ta bl e
4
i n c l u d e c o n t r i b u t i o n s f ro m t h e m o i s tu r e i n t h e
coal.,
so
t h a t t h e u l t i m a t e
a n a l y s i s I s on an "as - rece ived" bas i s . Th is form of t h e u l t i m a t e a n al y -
s i s
i s
r e q u i r e d by the ASPEN model. Before a s i mu l a t i o n c o u l d b e
per fo rmed ,
i t was
n e c e s s a ry t o matc h t h e ASPEN p re d i c t e d Lu rg i g a s i f i e r
o u t p u t r e s u l t s w i t h t h e e x p e r i m e n t a l l y de t er m in e d o u t p ut o f t h e Lurg i
g a s i f i e r u sed i n
the
SASOL
t e s t of
Kentucky No.
9
coa l '
(see
Appendix).
This
was accomplished i n two s t e p s : ( 1 ) by v a r y i n g t h e
REAL
v e c t o r
s p e c if i e d i n the ASPEN i n p u t f i l e a nd us ed by t h e s u b r o u t i n e DEVOL t o
form
the v o l a t i l e p r o d u c t s , a nd ( 2 ) by vary ing the t empera tu re a t which
t h e f o l l o w i n g f i r s t two r e a c t i o n s of t h e REQUIL
block
took p lace :
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4 8
Tab le
4.
C h c a i c a l
and
p h y si c al c h a r a c t e r i s t i c s
of Kentucky No. 9
coal .
UI imare a n a l y s i s (as r e c e i v e d coal)
Ash
Carbon
Bydrogerf
Ntt rogen
S u l f u r
oxygen
P r oximat s analy8
s
Mois t u r c
Fixed
carbon
V o l a t i l e
matter
Ash
15 . 4
5 9 . 6
5.3
1.2
3.5
15.0
100.0
x
8 . 2
43.4
33 .0
15.4
100.0
Sen t of combustton
=
1? , 4 7 5 B t u / l b ( d r y e o a l )
CO
+ H2Q -$ H 2 -b CO2
co
4-
3 H 2
*
CHq
4-
H26)
A comparisorz of the experimental and p r e d i c t e d g a s t f i e r r e s u l t s
(using
1620 and
141OoP,
respectfveiy, f o r
t h c t w o r e a c t i o n s above) i s shown in
Table 5.
’l”ma agreement is q u i t e
g o o d ; fu r t h e r
ref inem ent of the REAL
v e c t o r and/or t h e r e a c t i o n t empera tu res could make i t e v e n b e t t e r . Prom
t h e
SASOL
co a l tes’r, the amount of tar, C2+, and
phenol formed
were
known,
S l n c e
these c o ~ p o n e ~ t sr e o n l y
formed
i n t h e s u b ro u t in e DEVOL,
t h e i r Vector values r t 3e r e
e a s l l y
deter1114
ed.
L-I
a d d l t i o n , t h e water vec-
tor v a l u e
was
s e t t o a c co u n t f o r
the
amount of w a t e r i n d i c a t e d by
the
c o a l
proxjmate analysis.
r e mal n in g v e c t o r v a l u e s ( fo r N2, @ H q ,
CO,
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49
Table 5. L u rg i g a s i f i e r o u tp u t u s i n g Kentucky No.
9 coal
Mode1 SASOZ c o a l t es t
--
Clean
t a r
produced
as
X
W
c o a l
fed: 5.6
5 6
Dry gas composition, X
Wy
rogen
41.4 40.8
Carbon monoxide
15.4 15*9
Carbon
d iox ide
30,8 30.6
Methane 9 .
P . 4
C 2 +
0.9
0 * 9
N i t ro g e n
1.0
8,9
Hydrogen su l f ide
1,4 1.5
100.0
100.0
and CO,) w e r e
se t
t o
make
t h e t o t a l v e c to r
sum
t o u n i t y w h i le s l mu l ta -
n e o u s l y t h e y
w e r e
m a ni pu la te d , a l o n g w i t h t h e r e a c t i o n t e m p er a t u re s , t o
match the coal
t es t
d a t a .
The
f i n a l v e c t o r s o b t ai n ed were 0.0072,
0 .2863 , 0.340Q,
0.0131,
0 .0849 ,
0.0915,
0.0036,
and 8.1734 f o r t he f o r -
mat ion of
H,,
c=Hq H,O, 6 0 , C2+,
60
phenol , and
t a r ,
r e s p e c t i v e l y .
2’
I n t er m e d ia t e r e s u l t s
of
s e q u e n t i a l e x ec u ti o n o f the major groups
shown
i n Fig .
21. are
g i v en i n T a b le
6.
The o u t p u t of t h e f i r s t
major
group c o n s i s t s
of
t h e
cooled
g a s e s f ro m t h e
Lurgi
a n d Te x a c o g a s i f i e r s
and i s t h e i n p u t
t o
t h e R e e t i s o l
model. The C O S , NTl[3,
and
C2-C4
o u t p u t
streams
w e r e
n o t i n p u t t e d t o t h e R e c t i s a l mod el b ec a u se t h e y h av e n o t
y e t b een i n c o r p o r a t e d i n t o t h a t
model
($.e., b i n a r y i n t e r a c t i o n p a ra m e te r s
for
t h e s e s p e c i e s
were
not
a v a i l a b l e ) .
amount
of
naphtha e n te r i ng rthe second major group. Since ( 1 ) t h e SASOL
The
C6H6
e n t r y r e p r e s e n t s t h e
c o a l
t e s t s
d i d n ot i n d i c a t e t h e f o r m a t io n
of any
naphtha, and
( 2 )
t h e
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50
ZaZ11-. 6 .
Interme3iate
simulat. o n r e s u l t s f o r b ase 1 i n e T r i- S ta t e
case
G a s i f i e r a n d
&OH synthesis
c o o l i n g o u t p u t , K e r t i s o l o u t p u t ,
o u t p u t ,
MTG
Rectisol i n p u t
MeOH
s y n t h e s i s
i n p u t j.
np
u t
Coiiiponcnr (
1
-mo
1
h
1
(Ib-moP/h)
( lb -mol /h
)r
16,583
11,823
7 , 6 6 0
3,460,
100
418
333b
j i i
6a
173
41
-
1 4 , 5 3 2
7 , 5 5 1
1 , 4 4 1
3,306
. -
-
4 L2
0 . y
0.4
0.7
120
13
-
0.2
-
O u t p u t
stream
component,
b a t not u se d i n i n p u t stream.
MeO H s y n t h e s i s =
( 5 3 4 4
lb--mol/h)(32 ,042
l .b/lb-mol)
( 2 4
h/d3/(2000
h s e d as an i n p u t s t r e a n only .
e
1 b / t o n ) =
2670
t m s / d ; MeOh s y n t h e s i s from CasP 13
Flowsheet
= 2670
t 1 7 s d .
Case
13 f l awshee t
shows
naph tha
€rota
t h e
k c t i s o l .
u n i t be ing fed
t o
t h e
Tewaco g a s i f i r : r , the f o u r t h
major
group, nap htha hydrotreat- ing , has been
o m i tt e d i n
t h i s
o v e r a l l
sirraillation.
The
s i x
L4DPRC blocks i n
the
ASPEN B e e t i s o l modal are
shown
in
F i g . 8. The first two
of t h es e d i s t l l l a t i o n u n i t s
are
used
t o
remove
t h e S i mp u r i t y , w h t l e t h e r e ma i n i n g u n i t s are u s e d p r i ma s f l y t o
recover naph tha frvlln t h s s y n t h e s i s gas stream. 10a c t u a l ASPEN s imula-
t i o n s ,
a l l
of these
RADF RC
b l o c k s c o n v e rg e d i n d i v i d u a l l y , b u t o v e ra l l
2
convergence of t h e e n t i r e f l o ~ h e e t :
as
very d i f f i c u l t t o o b t a i n .
NUDE~GUS a t t e m p t s were made t o a c h ie v e convergence of the right h a l f
of
t h e f lowsheet (Fig . 8) by (1 ) b re a k i n g the
t i e s between
t h e t w o h a l v e s
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51
of t h e f l o w s h e e t elg. streams R E C W 1
RECLIQ2,
and
~~~~~~~~~~
and
( 2 ) r e p l a c i n g
he RADFRC
blocks by sLmple
SEP
b l o c k s , i n d i v i d u a l l y
and
in varying
combinat ions
Unfortunately
n e i t h e r o f these approaches
a i d e d t h e c o n v e rg e n c e p ~ o b l e ms e r e
were
some fnd ica t ions however ,
that
t h e c o n v e r g e n c e d i f f i c u l t i e s could be
t race
t o WO i n n e r loops in
t h e r i g h t hal f
of
the flowsheet* T h s e
inner
loops are d e f i n e d by
the
following: ( I )
streams RECACIDG, ~~~A~~~~
REGVAPPT, E C L I Q 1 9 ,
and
~ E ~ ~ A ~ 1 8 ~nd (2)
streams
R E C L E Q l 7 , R.ECLTQ18, and ~ ~ ~ ~ ~ ~ear ing
stream REcVM-as -might e o n f t r m
.if
t h e s e l o o p s
are
indeed t he souT(le o f
t h e c o n v e rg e n c e p ro b l e
The number of i t e r a t i o n s was
cot
i n c r e a s e d
above
the
default
v a l u e s
because
t h e
hPstory
f i l e d i d
nor
i n d i c a t e
that
t h e
maximum
number of
i t e r a t i o n s was bei ng approached . However, more i r r a t lo i a s and/or t h e use
of
d i f f e r e n t c o n v e rg e n c e schemes c ou ld be t r i e d t o see i f any
inprovement
c o u l d be made. For t h i s s im u la t io n , only
the
f i r s t t w o W F R C
blocks
were used. T h i s w a s r e a s o n a b l e s i n c e all. of
the H2S
i s removed from the
gas stream by t h e s e f i r s t two blocks, while t h e
remaining
b locks are
p r i ma r i l y u s e d to rec ov er naphtha. Sfmce th e
SASOL
coal
t e s t
d i d n o t
I n d i c a t e t h e f o r m a t i o n
of
any n a p h t h a , t h e use of the remain ing W P R C
blocks w a s no t cons idered
essential.
he
entire
ASPEN
language I s
i n cl u d ed i n t h e in p u t f i l e , b ut t h e r i g h t hal f of t h e flowsheet shown Pn
F i g . 8 ha s been commented ou t. These
could
be used by anyone d e s i r i n g
to check the recovery
of
t h e n ap ht ha i n t h e s y n t h e s i s g as stream.
The output front t h e Rec t i sa l u n i t , w i th i t a mch reduced content of
H25
and COz, is f e d i n t o
the
t h i r d
major
group : methanol sy n t he s i s ,
s h i f t , and methana tion . The pr ed ic t ed amount
of
methanol produced,
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52
2 6 7 0
tons/d, was forced
to agree closcly with
t lw 2670 tons/d
shown
on
t he Case 13
flowsheet by
varying
t h e
rt.,cyele r a t i o
in
the methanol
s y n t h e s i s a o d e l - To obtahn
agreement,
a recycle
r a t i o
o f
1.63 was used.
The
predicted composition and
pate of
SNG
prod;ic23ui-t a re
shown
in
Table 7 ,
d o n g w i t h the ~ u t p t s f the
fifth najor
groixp
(MTG,
fractionation, and
alkylation).
The ASPEN
block diagrams shorn
in
Figs. 13 and 14 f o r t h e frat-
tlonation and
alkylat- ion sections,
respecttvcly
use several
RlhDPRC
distillation blocks .
Ac;
was
t h e
case
for the Rect i soP model, these
RBDFRC
blocks
can
be
made
t o
converge
indtvPdually,
b u t
are
very
d i f -
f i c u l t
to
converge when
p a r t of the overall.
f lowshee t*
?%is, in these
Table 7.
Predicted o u t p u t s
f o r
baseline
T r f - S t a t e
case
------ _I
produc tton Model Case 13
Flowsheet
S NG, MNSCFI)
LPG, l b / h
I s o b u t a n e ,
lbJh
GasolPne
l b / h
Component
Tota l
39.5
4 , 3 0 0
8 5 , 4 0 0
1 -mo
I h.
30.7
205.7
1.2
4,104.2
4 ,341 .8
37-0
4,300
4 , 7 5 0
85,600
0.71
4 - 7 3
0.03
94 .53
100.00
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5 3
s i m u l a t i o n s t h e KmFRC blocks have been replaced by simple SEP blocks
which requfre no i t e r a t i v e c a l c u la t i o ns
u s i n g t h e r e s u l t s o b t a i ne d when t h e a p p r o p r i a t e i n d i v i d u a l
w a s used. The ASPEN
input
f % l e developed
i n
thBs work, however , conta ins
b o t h t h e
SEP
blacks
and the original RADFRC blocks , wfth t h e l a t t e r
being commented out.
use
a l l
or
p a r t
o f
t h e RADPRC
blocks,
along w i t h two
specaa l
FOR
b loc ks (ETSPEG and GSSPEC) u s e f u l f o r s e t t l n g t h e pr od uc t f l o ws a t es
from
blocks PIDEETHAN
and
MGASST
(see Pig.
13).
"I'laese blocks
were
c a l i b r a t e d
If d e s i r e d ,
a
user could remove the comments and
The
s i m u l a t i o n p r e d i c t s t ha t:
39.5
MPI
SCFD
af
SNG,
contaitihng
94.5
methane, w i l l be produced.
SCFD shown on t h e Case
13
f lowshee t .
The
models p r e d ic t t ha t 4760 Ib/h
This
value compares favor ably wi th th e 37 MM
of i sobutane
i s
formed (stream XSIBUT on F4.g.
1 4 ) ,
which i s 0,2X
higher
t ha n the f lowske et va lue of 4750
lb /h .
The p r e d i c t e d g a s o l i n e v a l u e
(stream GAS on Fjg.
1 4 )
o f
85 ,40 l b / h
i s 0.2X less
t ha n the f lowshe e t
v a l u e
o f
85,600
l b f h .
The pred ic ted LPG produc t ion i s f d e n t i c a l
to the
f lowshee t va lue of
4300
lbfh. These
predicted
produe t
ra tes
w e r e
o b t a h e d by m od if yi ng t h e y i e l d s t r u c t u r e u se d
f o r
the
MTG
r e a c t o r
so
t h a t t h e LPG,
isobutane,
and gaso l ine produc t
ra tes
would match the
Tr i - S ta t e f l owshe e t .
This
T ri -S ta te y k l d s t r u c t u r e
i s
shown In Table 8.
When t he y i e l d s t r uc tu re g iven by Schreiner9 and shown
i n
Table 9 w a s
use d , t he p r oduc t ion
ra tes
p r e d i c t e d
by
the models
were
changed con-
s i d e r a b l y ,
as
Shawn
in
Table
10.
It
should
be
n o t e d t h a t
a
s l i g h t
e r r o r
w i l l oc cu r i n t he a tom bala nc e a round th e r e a c t o r when e i th e r of t h e s e
y i e l d s t r u c t u r es are used . This e r ro r
i s
caused by lumping a l l
of
t h e
products beyond C g i n t o a s ing le - te r m l a be le d ga so l ine and the n
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a
m
N
u
2
0
L
Q
A
r
n
g
v
n
m
n
e
m
m
O
r
N
4
N
a
4
~
h
0
l
0
0
0
0
0
0
8
0
0
0
0
0
0
0
N
o
m
o
o
o
o
o
o
o
o
o
o
o
o
o
o
8
a
a
P
9
3
1
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
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Schreiner
y i e l d T r i - S t a t e ytelnz
Prcrdlact:ican
S
:
TU
ct
re seructure
assigning this pseudocomponent the p r o p e r t i e s of n-heptane a If these
higher
moleanlar
weight products were not
combined,
however, an
addi-
tional 31
components
w o u l d
have
t be alsed
i n
t h e
r P t d n d e r
of tile
simulati@ln. us ing Schre iner
s yfeld
s t n x t u r e 9 the predfeted aaollint of
gasoline produced is eonsfderably reduced, w h i l e the p r e d i c t e d m o u n t
of
isobutane and LPG
produced
are larger,
Thus
the bas ic d:EEfererzce between
t h e
t w o y h l d s t r u c t u r e s
has been to
shift
produet format ion toward the
higher carbon ( $ . e . * gasalFne) end of t h e
groc3uc.t
s l a t e .
4 .2 FULL-SIZE TRP-STATE
CASE
I n
t h e f u l l - s i z e Trl -S tace case9 960 t o n s of coal. per 11oer1- would
b e f e d to tbe
L u r g i
gas t f i e r . This case was sIwul.ated to ensure that
the d e v e l o p e d could opera te
over
a range of flow
rates.
e
intermediate s i m u l a t f s n results are shown
in
Table 11. ~o~~~~~~~~ with
Table 6
shows that each
component of
t h e
gasifier o u t p u t
streams have
been increased by a f ac tor of 4 , the same factor t h a t
t h e
coal
f e e d
rate
h a s been increased, Similarly, t h e Kect isol o u t p u t
streams
have been
Increased by a f a c t o r of
4
as cornpared to
Table
6 , Tne R s c o n t e ~ ~ tf
2
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56
66,334
30 , 6 41
4 7 , 2 9 2
1,571
2 ,044
2
5u
593,
245
6h9
31
3 0 , 2 0 4
1 3 , 2 2 2
5,764
-
-
1,647
a
2.8
1.6
2 .8
481
54
-
-
1,138
27 ,
me
the
gas
stream has
been
reduced
by
99.867: so that t he t o t a l gas stream
c o n t a i n s orrly 24 ppm H S
i s
a l s o a factor
of i~ t.lmes ehe baseldne case? v a l u e
of
2670 tons /d .
'%he
amount
of
n e t h a n o 1 produced, 10,680 tnns/d,
2
The pred i c t ed product r a t e s f o r t h f s case are shown I n
Tab1.e
12.
A s w o u l d be
expected,
since ethanol i s being converted t o g a s o l i n e , the
preddr t e i l
g as o l i n e p r s d u c t I o n r a t e
of
341,6363 l b / h f s 4
t f w s
the base-
l i n e
val.ue
cf
85 , 400 Ib /h . The
est imzited i s o b u t a n e ,
SNG, and
LFG ra tes
are
a l s o
4
t i m e s
the
baseline
va lues .
Thus
the
change i n
coal
f e e d
r a t e
p r o p a r t I o n a P l y
changed
a14 the o u t p u t p ro d u c t rates , showing
tihe
rangeability of the ASPEN
models developed
i n Lhis s tudy .
Demonstrating such
v e r a a t - l l i t y
and
range
of
o p e r a b i l i t y
i s
very
Impor tan t f o r any process simulation s i n c e
it
shows i f the wnsde.1~
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5
7
Table 12. P r e d i c t e d o u t p u t s
for
f u l l - s i z e T r i - S t a t e
case
Produc t ion
Model
SNG, MlMSCFD 158
LPG, l b / h 19,200
Gasol ine ,
l b / h 341,600
I sobu ta ne , l b /h
SWG
u
l b V O l / h
x
elm
omponent
H2 118
0.68
N 2 822
4.74
CO 5
0 03
C R 4 16,376 94 55
T o t a l
1 7 , 3 2 1 100"80
Meat
of combustion
(HHV) =
956
Btu/SCF
__
developed have
been
s u f f i c i e n t l y g e n er a li z ed . In t h i s case, s p e c i f i c
values
f o r
c e r t a i n
feeds, splits, and
o u t p u t s
w e r e
r e p l a c e d w i t h r a t i o s ,
o f t e n u s in g
FORT
b l o c k s t o
set
i n i t i a l
estimates.
Similar
te s ts
of
any
new models t h a t
are
developed should
be
made
t o
a s s u r e g e n e r a l i t y .
4 . 3 ILLINOIS No. 6 FEED
I n o r d e r t o d em on st ra te t h e v e r s a t i l i t y of the ASPEN models developed
i n t h i s s t u dy , t h e b a s e l i n e T r i- S ta t e
case ( i r e .
240
tons of
c o a l f e d
p e r
hour )
was s i mu l at ed u s i n g I l l i n o i s
N o *
6 coal
as
f ee d t o t h e
Lurgd
ga s i f i e r . 'She c hemica l and phy s i c a l c h a r a c t e r i s t i c s of t h i s c oa l , shown
i n Table 13, w e r e taken from t e s t data.
16
Table 14 shows that the composit ion of t h e
d r y gas produced using t he
Illinois N o . 6
c o a l , u s i n g
the same R E f i vector a d reaction temperatures
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58
Table
13. Chemical
and
physical
characteristtcs
o f 11
1.j-noE.s
Ma. 6
coal.
Ash
C a
a-?ron
Hytl w g e
Nitrogen
S u l f u r
Oxygen
9.0
64 .3
5.5
1.2
2.8
17.2
100.0
Pro s im a t e ana s s
x
Mo
i
turn
Fixed
carbon
V o l a t i l e natter
Ash
10.3
46.0
34. 7
9.0
100.0
Beat of combust-ion = 12,770 B t u / l b (dry c oa l )
1111
_ ..I.....I
___ ___.
TabLe 14 , L ur gi g a s i f i e r o u tp u t u s i n g Illinois Nae 6 coal
as
compared
to Kentucky No. 9
coal
14.1..
No. 6 Ky. No.
9
coal.
coal
Clean &ar produerd ,
as
MAF coal f e d :
Dry
gas composi t ion, %
Hydr ogeri
Carbon
momxide
Carbori d i o x i d e
Methane
c 2
-1-
N i t rogen
Hydrogen sulfide?
5.9
4 0 , 3
16.0
30.
'7
10.0
1 0
1.0
1.0
5.6
41 .4
15.4
30.8
9 . 1
8.9
1.0
1.4
100.0 100.0
~ ..
.̂.,...
_._
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59
as
previously,
is ve r y sfrnllar r a
t ha t p r e d i r t x d
for the Kentucky
No,
9
coal,
the Tl.lincis
c o a l ,
while a
s l i g h t l y
lower pereenmge o f kydrogen i s expected,
Because
of its lower sulfur e m t e n t ,
the
amoan: of BzS predicted i s
c ons ide r a b ly
less ttiian that predtcted
u e b g the
Kentucky 9 coal.
Higher percentages of
carban
mc~noxideand aaetha-tae a r ~r e d i c t e d for
The
i n t e r m e d i a t e
simulation resulss re shewn
in Table
15.
X
c o w
parison with Table 6 shows that the
g a s i f i e r
asintputs are
very
simflar
a n d t h a t
the
Rect isol u n i t
again remooes
over
99% of
the
B2S from
t h e
gas
stream. The fact that some HzS Ps
p r e d i c t e d
t o r e m k n gn
the
synthesis
gas
stream
for
each of these sinnuPations Pndicates
t h a t
zinc
o x i d e
p a r a
b.as
should
probutaiy be
~ L X o
E PBxPc31 syntbes
s to
a vo id pofsoning sf
its
c a t a l y s t , The pr-ed-lcted am u :~ t of me t Z~a no2
pro-
duced,
2772 tuns/d is 3.8 greater thzera ?:Ire baselhue
m ~ < ?
alueR
The
estimated
outputs;
are
given
in
Tab le
16,
Bison w el.1
Table
7 shows
t h a t
more SNG2 LPG, lisobaitarae, an
g
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6 1
g a s i f i e r ,
synthesis
gas c oo l ing , R e c t i so l , me tha no l syn the s i s ; , methano l-
to - ga so l ine ,
@@-shift,
n e t h a n a t i o n , and na ph tha hyd r o t r e a t ing . In addi -
t i o n , an enhancement has been
m d e
t o
ASPEN
t o a ll o w
for
t h e d i r e c t
i n p u t
of
c o a l h e a t
of
combust ion va l ues , and th re e
FORT
programs
were
de ve lope d t o hand le t he d e v o l a t i l i z a t io n and de compos i ti on of c o al i n
dl
g a s i f i e r a nd t h e h a nd l i ng
of
bojl ler feed water.
S imula t ions
were
made of t h r e e c a se s :
(1)
t h e b a s e l i n e T r i - S t a t e
f lowsheet with Kentucky
NoI 9
c o al fe d i n a t
240 tons,%;
( 2 )
a
f u l l - s i z e
Tr i -S ta te case wi t h Kentucky No.
9
c o a l f e d i n
at 960
tone/h; and
( 3 )
t h e
b a s e l i n e T r i - S t a t e
case
w it h I l l i n o i s k
6
c o a l f e d
at 240 tons/h,
P r e d i c t i o n of th e s yn th es is gas composi t ion produced by the h r g i
g a s i f i e r was c a l i b r a t e d u s i n g t h e SASOL c o a l
t e s t
data . For t h e first
case,
t h e s i m u l a t i o n
was
f o r c e d t o match the p r odu c t ion
ra tes
of metha-
n o l , LPG, i sobu ta ne , and g a s o l i n e as i nd ic a t e d by the T r f - S ta t e Case 13
f lowshee t . This w a s accomplished hy (1) u s i n g a r e c y c l e ratio of 1 , 6 3
i n
th e methanol s yn th es is model , and
( 2 )
modify ing the
EaTG
r e a c t o r y i e l d
s t r u c t u r e . C ba dr up li ng t h e c o a l f e e d
r a t e
of t he f i r s t
case,
the second
ease i n d i c a t e d t h a t e x a c t l y f o u r times as much SNG, LPG, i s a bu ta ne , a nd
ga so li ne would be produce& The u s e of I l l i n o i s No.
6
coal
i n
the t h i r d
case r e s u l t e d Pn o u t p u t s s l i g h t l y h i g h e r t h a n t h o s e p r e d i c t e d by
Kentucky
No.
9 coal . The a n t i c i p a t e d i s o b u t a n e ,
LPG,
and g a s o l i n e pro--
d u c t i o n
ra tes
are 3.8 h i g h e r f o r the I l l i n o i s coal, whi le t h e SNG pro-
duction would be expec ted t o be 12%h ighe r .
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6. REFERENCES
3.
4 .
5 .
6 .
7.
8.
9 .
10.
11.
12.
13.
Paul
F. R.
Kudol.ph,
P. K.
Hzrbes t , at id H. Vferrath,
" G a s i f i c a t i o n
of
US--NestF_j-n1 and Eastern Coals in the Jnrrgi
Ery-Ash
and t h e
B r i t i s h G a s j h r g i
S1
aggiwg G a s i f i e r s , presen%sd t the 4 th Annual
Coal U t P I i z a t i s n Conference9 i%oust.oii,
Texas,
NOY.
17-19, 1981.
R.
Salmon, M.
S..
E d w a r d s , and R.
M.
Whim, Pmduc t - io r l
of
MethmpzoZ
a d
Me-t ruriol-Related
F u e h
from
Coal,
OWL-5664
(May
1980).
.Je C. SePover, '"Coal
Conversfon t o
Methanol Gasol ine and
S NG,
p r e s e n t e d
at the
31st
-Annual AIChE bkctirng, Defrrc~it,
Michigan,
P*ejg,
16-19,
1981.
T ~ i - S a t o
ynfuel6
Pmjec t
Reviey Cont rac t 835504 , Tr E- S t a t e
S y n f i . ~ I s ompany (June 1982).
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1
A b r i e f srimmary
of
the
SP.SOL
coal
t e s t
da ta is
shown
in Table 17.
These
d a t a
represent a
vary
small
p a r ' s
of t1-r~
overall
r e p o r t
and
s l ~ o u l d
not
b e i n t e r p r e t a d
as
r e p r e s e n t i n g
the d e s i g n
condf
t loras
of
t h e
T r S - S t a t e pro.jec&, Extensive da ta and
di-scuesiicptrc of
t h e coal test
ate
i n c l u d e d
i n
the.
DOE
r e p o r t , ;mad i r t @ r e s t e d
e a de r s re
r e f e r r e d
t o i t
1
The
d a t a p r e s e n t e d in Tablc
17
wem-r. usedl to t leterndne the flow
r a t e s of oxygen, steam, and
water to
the Lurgrh
gasifier
In thts
simulation. In
a d d i t i o n ,
the average
g a s i f i e r ouP:let
t e mp e r a t u r e o f
1030'F
w a s
used in
t h e
s imula t ion . Furt1-tc-c
coa l
r e s t r e s u l t s (i.ea,
produet gas
composition
a n d
acasunl: of
clean
t a r produced)
wcrc prc~se i i ted
e a r l i e r
i n T ab le
5.
Ta b l e 17. Fec?d ra tes
used
I n SASOZ c o a l t e s t
and
L u r g i gasifier s imulat l rsn
of
b a s e l i n e "b"ri-State
case
Coal
(MhI.')
Ash
Moisture
15.9 0 ,764
3 6 6 , 2 2 6 0 .74 i .
3.2 0 . 154 7 3 , 5 7 6 0 , 1 5 4
1 . 7
(I*
82 39,137 O e
82
---.----
T o t a l as r e c e i v e d c o a l
20. E?
479 ,039
Oxygen
S t e a m
Wareer
G a s i f i e r
o u t l e t
t e m p e r a t u r e OF
8.6
0 ,413
197,741 0.413
34 ,6 1.663
796 ,864
1.663
7.7
0.370
177,337
0 .378
1000- 1060 1030
65
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8/16/2019 Aspen Modeling Tristate Icl
74/76
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8/16/2019 Aspen Modeling Tristate Icl
75/76
ORNL
/n.I-8611
Dist Category UC-9063
INTERPJAL DISTRIBUTION
1-5.
6 ,
7 .
8-12.
13 I
14-18 e
1 9 .
20.
21
2 2 .
23
a
24 .
2 5 .
2 6 .
27 - 31 .
32
e
3 3 *
34 *
35 *
36.
3 7 .
J. M . Begovich
K. 7 .
Canon
J . H.
C l i n t o n
S .
D.
C l i n t o n
B. D.
Cochran
E.
D. Collins
T .
L .
Donaldson
P. w F i s h e r
C . W.
Forsberg
R. K.
Genung
H a
W
Godbee
M . V . H e l f r i c h
J .
R ,
Hightower
P.
J .
Johnson
R , F
Judksns
J.
A.
K l e