11 Applicability of the Meyers Process for Desulfurization of U.S. Coal (A Survey of 35 Coals) J. W. HAMERSMA, M. L. KRAFT, and R. A. MEYERS
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TRW
Systems and Energy, Redondo Beach, CA 90278
The Meyers process (1,2) is a new chemical leaching process which allows many coal-fired power plants and industrial sources to meet federal and state sulfur oxide emission standards without the use of flue gas cleaning. This process uses a regenerable aqueous ferric sulfate leaching unit to chemically convert and remove the pyritic sulfur content of the coal as elemental sulfur and iron sulfate. Although only pyritic sulfur is removed (organic sulfur remains), the Meyers process has wide applicability for converting U.S. coal reserves to a sulfur level consistent with present and proposed governmental sulfur oxide emission standards. Thirty-five mines from the major coal basins were investigated in this study. Because of the relatively high pyritic sulfur and low organic sulfur contents and because of high production of Appalachian coals (70% of current U.S. output), the Meyers process appears to have major impact in this area. In the Meyers process, aqueous ferric sulfate is used at 90°130°C t o oxidize selectively the pyritic sulfur c o n t e n t o f coal t o y i e l d i r o n s u l f a t e and f r e e e l e m e n t a l s u l f u r a s shown i n E q u a t i o n 1. The i r o n s u l f a t e d i s s o l v e s i n s o l u t i o n w h i l e t h e f r e e s u l f u r i s removed f r o m t h e c o a l m a t r i x e i t h e r b y v a p o r i z a t i o n o r s o l v e n t extraction. The l e a c h i n g ( o x i d i z i n g ) a g e n t i s t h e n r e g e n e r a t e d a t a s i m i l a r t e m p e r a t u r e u s i n g o x y g e n o r a i r and i s r e c y c l e d w h i l e p r o d u c t i r o n s u l f a t e s a r e removed b y l i m i n g a n d / o r c r y s t a l l i z a t i o n . 4.6 F e ( S 0 ) 2
4
3
+ 4.8 H 0 + F e S 2
2
10.2 FeSO^ + 4.8 H S 0 2
4
+ 0.8 S ( 1 )
The d e t a i l e d c h e m i s t r y , l e a c h i n g c o n d i t i o n s , r e a c t i o n k i n e t i c s , p r o c e s s e n g i n e e r i n g , and c o s t e s t i m a t e s h a v e b e e n p u b l i s h e d (3,4,5,6,7), and a r e a c t o r t e s t i n g u n i t has been b u i l t . T h i s c h a p t e r p r e s e n t s e x p e r i m e n t a l r e s u l t s and d i s c u s s i o n for: p y r i t i c s u l f u r removal from c o a l , p y r i t i c s u l f u r p a r t i t i o n by f l o a t - s i n k s e p a r a t i o n f r o m t h e same c o a l s , t h e e f f e c t o f t h e Meyers p r o c e s s on t h e t r a c e element c o n t e n t o f t h e t r e a t e d c o a l s , and a p p l i c a b i l i t y o f t h e M e y e r s p r o c e s s f o r m e e t i n g a i r p o l l u t i o n
143
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
144
C O A L DESULFURIZATION
c o n t r o l standards. T h i s w o r k was p e r f o r m e d u n d e r c o n t r a c t t o E n v i r o n m e n t a l P r o t e c t i o n Agency ( 8 , 9 ) .
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Sulfur
the
Reduction
A summary o f t h e s u l f u r a n a l y s e s o f t h e r u n - o f - m i n e c o a l u t i l i z e d i n t h i s s t u d y i s shown i n F i g u r e 1. The o r g a n i c and p y r i t i c s u l f u r c o n t e n t s a r e p l o t t e d a l o n g t h e x-and y - a x i s r e s p e c t i v e l y w h i l e t h e sum o f t h e s e v a l u e s f o r a g i v e n c o a l c a n be reaù f r o m t h e diagonal lines. The a v e r a g e c o a l f o r t h i s s u r v e y c o n t a i n e d 2.02% p y r i t i c s u l f u r and 3.05% t o t a l s u l f u r . This corresponds to the U.S. B u r e a u o f M i n e s a v e r a g e f o r 325 raw c o a l s ( 1 0 ) , i n d i c a t i n g that the survey c o a l s r e p r e s e n t r e a s o n a b l y the s u l f u r d i s t r i b u t i o n i n U.S. coal. The r e s u l t s t o d a t e f o r c h e m i c a l r e m o v a l o f p y r i t i c s u l f u r (100-150 μ t o p - s i z e c o a l ) and t h e o p t i m a l r e s u l t s f o r c o n v e n t i o n a l c o a l w a s h i n g ( b a s e d on t h e 1.4 mm, 1.90 f l o a t f r a c t i o n o f a f l o a t s i n k a n a l y s i s ) a r e shown i n T a b l e I , i n t e r m s o f t o t a l s u l f u r c h a n g e s , and i n g r a p h i c a l f o r m i n F i g u r e 2. The t a b l e d e s c r i b e s t h e r e s u l t s o b t a i n e d on c o a l s w h i c h c o n t a i n e d s u f f i c i e n t p y r i t i c s u l f u r f o r a c c u r a t e s u l f u r r e m o v a l d e t e r m i n a t i o n ( i . e . , >0.25% w/w). Three of the mines sampled were below t h i s l i m i t and, t h e r e f o r e , do n o t a p p e a r i n t h e t a b l e . A c t u a l t o t a l s u l f u r v a l u e s b e f o r e and a f t e r c h e m i c a l r e m o v a l a r e shown i n columnsΟ and 4. These may be compared w i t h c o l u m n 5, w h i c h shows s u l f u r v a l u e s w h i c h c a n be o b t a i n e d w i t h f u l l p r o c e s s o p t i m i z a t i o n . T h i s l a t t e r v a l u e was c a l c u l a t e d by a d d i n g t h e a c t u a l r e s i d u a l p y r i t i c s u l f u r and s u l f a t e c o n t e n t s of the c o a l to the i n i t i a l o r g a n i c s u l f u r v a l u e a f t e r c o r r e c t i o n f o r any c o n c e n t r a t i o n e f f e c t s r e s u l t i n g f r o m a s h r e moval. I n the survey program, complete removal of r e s i d u a l e l e m e n t a l s u l f u r and s u l f a t e was n o t a l w a y s o b t a i n e d s i n c e c o n d i t i o n s were s t a n d a r d i z e d but not o p t i m i z e d f o r each i n d i v i d u a l c o a l . T h u s , f o r e x a m p l e , a l t h o u g h 96% p y r i t e c o n v e r s i o n was o b t a i n e d f o r t h e B i r d No. 3 c o a l , t h e t o t a l s u l f u r was r e d u c e d t o 0.80%, n o t t h e t h e o r e t i c a l 0.45% c a u s e d by t h e s e e f f e c t s . These p r o c e s s i n g p r o b l e m s h a v e now b e e n r e s o l v e d as p a r t o f o t h e r p r o j e c t s ( 3 , 9 ) , and t h e v a l u e s shown i n c o l u m n 5 can be c o n s i d e r e d t o r e p r e s e n t the t r u e p o t e n t i a l of the p r o c e s s . Because of the widespread a p p l i c a t i o n of p h y s i c a l c l e a n i n g t e c h n i q u e s f o r removal of nonc o m b u s t i b l e r o c k ( w h i c h i n c l u d e s v a r y i n g amounts o f p y r i t e a l o n g w i t h some c a r b o n ) f r o m c o a l , f l o a t - s i n k f r a c t i o n a t i o n was p e r f o r m e d i n o r d e r t o d e f i n e t h e r e l a t i v e u t i l i t y o f w a s h i n g and chemical d e s u l f u r i z a t i o n f o r each c o a l . The r e s u l t s a r e shown i n c o l u m n 8 and a l s o i n F i g u r e 2. The s u l f u r r e d u c t i o n p o t e n t i a l o f t h e M e y e r s p r o c e s s i s h i g h l y a t t r a c t i v e and i n p a r t i c u l a r i t was found t h a t : (1) The M e y e r s p r o c e s s , a t i t s c u r r e n t s t a t e o f d e v e l o p m e n t , removed 83-99% o f t h e p y r i t i c s u l f u r c o n t e n t o f t h e 32 coals s t u d i e d , r e s u l t i n g i n t o t a l s u l f u r content r e d u c t i o n s o f 25-80%
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
11.
HAMERSMA
Meyers Process for Desulfurization
E T A L .
APPALACHIAN INTERIOR BASINS WESTERN
Ο Δ •
Ν 24 Ν- 7 Ν -• 4
TOTAL SULPHUR,
% w/w \
\
\
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\
Δ
ο
\
Ρ
\
Ο
Δ
\ \
\
\
N
v
ο
° n
Ο Ο
\
v
\ ό
Ο
V , \
^o
OOO
\
S
\ \
co\ L_2 l l _ 0.5
1.0
\
\
_J 1.5
\
\
M . 2.0
2.5
ORGANIC SULPHUR, % W/W
ι
5
6
7
8
Figure 1.
Sulfur forms of sampled U.S. coals
Figure 2. Sulfur content of survey run-ofmine coals (curve a), the same coals physically cleaned (curve c), and chemically de sulfurized (curve b)
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
Navajo Kopperston No. 2 H a r r i s Nos. 1 & 2 Colstrip Warwick Marion Mathies Isabella Orient No. 6 Lucas Jane Martinka North River Humphrey No. 7 No. 1 Bird No. 3 Williams Shoemaker Meigs Fox Dean Powhattan No. 4 Eagle No. 2 Star Robinson Run
Mine 0..8 0.,9 1.,0 1.,0 1.,4 1.,4 1.,5 1.,6 1.,7 1.,8 1.,8 2.,0 2. ,1 2,,6 3..1 3.,1 3..5 3..5 3,.7 3,.8 4,.1 4..1 4,.3 4,.3 4,.4 0,.6 0,.6 0..8 0,.6 0,,6 0,,7 0,,9 0,,1 0..9 0..6 0,,7 0,.6 0..9 1..5 1..6 0,.8 1..7 1,.7 1,.9 1,.6 2,.1 1,.9 2,.0 2..5 2,.2
0.,5 0..5 0.,6 0.,7 0.,4 0.,6 0.,5 0.,5 0.,8 0.,5 0.,6 0.,8 0.,8 1.,2 1.,4 0.,4 1.,4 1.,5 1,.7 1..2 1,.6 1,.9 1,.9 1,.8 1,.6
% T o t a l S u l f u r w/w i n Coal2 A f t e r Meyers Process Current Revised Initial Results Processing^ 90 92 94 83 92 96 95 96 96 94 91 92 91 91 90 96 96 96 93 89 94 85 94 91 97
25 33 23 30 54 50 36 54 44 64 63 70 55 42 48 75 50 51 48 57 49 53 54 43 50
Meyers P r o c e s s " Pyrite Total S Conv. Decrease (% w/w) (% w/w)
Summary of P y r i t i c S u l f u r Removal Results^(100-150 u t o p - s i z e coal)
Nos. 6,7,8 Campbell Creek Eagle & No. 2 Gas Rosebud Sewickley Upper Freeport Pittsburgh Pittsburgh H e r r i n No. 6 Middle K i t t a n n i n g Lower Freeport Lower K i t t a n n i n g Corona Pittsburgh Mason Lower K i t t a n n i n g Pittsburgh Pittsburgh C l a r i o n 4A Lower K i t t a n n i n g Dean P i t t s b u r g h No. 8 I l l i n o i s No. 5 No. 9 Pittsburgh
Seam
Table I.
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1.0 1.2 1.7 1.5 1.4 0.7 0.8 0.8 2.2 1.9 2.3 1.5 2.3 3.6 2.8 2.0 3.0 3.3 2.9 3.0 3.0
0.8 0.9
% Sulfur i n Coal^ After FloatSink
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
No. 11 No. 9 (W. Ky.) No. 9 Upper F r e e p o r t Meigs Creek Des M o i n e s No. 1 P i t t s b u r g h No. 8
Seam 4.5 4.5 4.8 4.9 6.1 6.4 6.6
Initial
% Total
1.7 2.0 2.8 0.8 3.2 2.2 2.7
1..6 2. ,1 2. ,2 0..5 2. ,7 1. ,7 2. ,1
S u l f u r w/w i n C o a l 2 ~ A f t e r Meyers Process Current Revised Results Processing^ 93 89 91 965 94 92 89
47 55 42 80 47 65 59
Meyers P r o c e s s " Pyrite Total S Conv. Decrease (% w/w) (% w/w) 3,.2 2,.9 3..5 2,.1 4,Λ 3.,9 4.,6
% Sulfur i n Coal^ After FloatSink
moisture-free
Run
using
a t 200 m χ 0.
Calculated
l a t e s t process
improvement.
14 mesh χ 0, i s d e f i n e d
basis.
1.90 f l o a t m a t e r i a l ,
Dry,
here as the l i m i t o f c o n v e n t i o n a l
coal
cleaning.
A 100 g s a m p l e o f c o a l was r e f l u x e d w i t h 2 L o f I N F e 2 ( S 0 4 ) 3 s o l u t i o n . A f t e r 4-6 h r s , t h e r e d u c e d s o l u t i o n was f i l t e r e d f r o m t h e c o a l a n d t h e c o a l was r e f l u x e d w i t h 2 L o f f r e s h I N F e 2 ( S 0 4 ) 3 . A f t e r a t o t a l e x t r a c t i o n t i m e o f 10-24 h r , t h e s l u r r y was f i l t e r e d and t h e c o a l c a k e was washed w i t h 0.2N H2SO4, t h e n w i t h w a t e r t o remove r e s i d u a l s u l f a t e . T o l u e n e (400 m l ) e x t r a c t i o n o f t h e c o a l removed e l e m e n t a l s u l f u r . The c o a l c a k e was t h e n d r i e d i n a vacuum oven a t 100-120°C.
Homestead Camp Nos. 1 & 2 Ken Delmont Muskingum Weldon No. 11 Egypt V a l l e y No. 21
Mine
Table I continued.
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148
C O A L DESULFURIZATION
(2)
T w e l v e (38%) o f t h e c o a l s w e r e r e d u c e d i n s u l f u r c o n t e n t to t h e 0.6-0.8% s u l f u r l e v e l s g e n e r a l l y c o n s i s t e n t w i t h t h e F e d e r a l New S o u r c e P e r f o r m a n c e S t a n d a r d s ar»H many s t a t e standards I n a l l c a s e s , t h e M e y e r s p r o c e s s removed s i g n i f i c a n t - t o v e r y l a r g e i n c r e m e n t s o f s u l f u r o v e r t h a t s e p a r a b l e by physical cleaning I n two c a s e s , t h e C o r o n a and M a t h i e s m i n e s , c o a l c l e a n ing a c t u a l l y r e s u l t e d i n a s u l f u r content i n c r e a s e i n the f l o a t product.
(3)
(4)
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Rate of P y r i t i c
S u l f u r Removal
The r e m o v a l o f p y r i t i c s u l f u r was measured as a f u n c t i o n o f t i m e a t 100°C f o r 18 A p p a l a c h i a n and 3 e a s t e r n i n t e r i o r r e g i o n coals. The r e s u l t s a r e d i s p l a y e d i n T a b l e I I , w h i c h shows t h e range of r a t e s observed. I t was assumed t h a t t h e e m p i r i c a l k i n e t i c r a t e e x p r e s s i o n (3) w h i c h was d e v e l o p e d p r e v i o u s l y f o r t h i s process i s a p p l i c a b l e to a l l c o a l s i n the survey. The k i n e t i c e q u a t i o n c a n be s i m p l i f i e d by h o l d i n g t h e r e a g e n t c o n c e n t r a t i o n r e l a t i v e l y c o n s t a n t , as was t h e c a s e i n t h i s s t u d y , t o y i e l d E q u a t i o n 2: -d[W ] p
, °τ» 2 _ . = k W = r a t e of p y r i t e D
removal
(2)
dt w h e r e : W = w e i g h t p e r c e n t p y r i t e i n t h e c o a l , and k° = f u n c t i o n of tempeTâture, c o a l t y p e and p a r t i c a l s i z e . By i n t e g r a t i n g E q u a t i o n 2, t h e f r a c t i o n o f p y r i t e removed as a f u n c t i o n o f t i m e i s shown i n E q u a t i o n 3: p
1-F where: F centration, The i n i t i a l f o r WWp ° and n
Ρ
_
(3)
F
f r a c t i o n o f p y r i t e removed, W = i n i t i a l p y r i t e con and t p = t i m e t o r e m o v a l a t T r a c t i o n F. w e i g h t p e r c e n t o f p y r i t i c s u l f u r Sp° may be s u b s t i t u e d E q u a t i o n 3 be r e a r r a n g e d t o E q u a t i o n 4 p
ο k = a c t u a l r a t e constant
(A)
T h u s , a s s u m i n g 80% r e m o v a l as a p o i n t o f c o m p a r i s o n , t h e v a l u e s o f 1/Sp_°_t80% shown i n c o l u m n 6 o f T a b l e I I i n d i c a t e t h e r e a c t i v i t i e s of t h e p y r i t e c o n t a i n e d i n t h e c o a l s t h a t w e r e s t u d i e d . A l a r g e amount o f e x p e r i m e n t a t i o n and e n g i n e e r i n g has b e e n p e r f o r m e d u s i n g r a t e d a t a o b t a i n e d f o r M a r t i n k a (3) c o a l ; t h e r e f o r e , t h e M a r t i n k a c o a l Sp°tftQ% has b e e n s e t e q u a l t o 1 as a b a s i s o f c o m p a r i s o n (as shown i n c o l u m n 7 ) .
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
Campbell Creek E a g l e & No. 2 Gas Upper F r e e p o r t Middle Kittanning Pittsburgh Pittsburgh No. 9 Corona No. 9 Pittsburgh P i t t s b u r g h No. 8 No. 11 Lower K i t t a n n i n g Pittsburgh Lower K i t t a n n i n g C l a r i o n 4A Lower K i t t a n n i n g Dean M e i g s C r e e k No. 9
Seam 149 149 149 100 149 100 149 149 100 100 75 149 75 149 149 149 100 100 149 0.47 0.49 0.90 1.42 2.19 2.23 2.85 1.42 2.66 1.05 2.75 3.11 3.09 1.07 1.42 2.19 2.87 2.62 3.65
Sp°
forPyritic
Top Size (Microns)
R e l a t i v e Rate Constants
2.0 2.3 3.0 3.25 2.9 3.0 2.5 5.0 3.0 9.0 4.0 3.5 4.5 13.0 10.0 8.5 8.0 10.2 8.0
80% (hrs)
u
Sulfur
1.1 0.89 0.37 0.22 0.16 0.15 0.14 0.14 0.13 0.11 0.091 0.092 0.072 0.072 0.070 0.054 0.044 0.037 0.034
^ % 0 %
1
R e a l t i v e Rate
Removal
16 13 5.3 3.1 2.3 2.1 2.0 2.0 1.9 1.6 1.3 1.3 1.0 1.0 1.0 0.77 0.62 0.53 0.49
Relative Rate
2
Constants
l/S>p_tgQ0£ r e l a t i v e t o v a l u e f o r M a r t i n k a m i n e .
o
As i n f o o t n o t e 1 o f T a b l e I , e x c e p t t o l u e n e e x t r a c t i o n was o m i t t e d . P y r i t e removal r a t e data was o b t a i n e d by p y r i t e a n a l y s i s o f c o a l s a m p l e s o b t a i n e d f r o m s l u r r y a l i q u o t s by c e n t r i f u g a t i o n .
K o p p e r s t o n No. 2 H a r r i s Nos. 1 & 2 Marion Lucas Shoemaker Williams Ken North River Star Mathies P o w h a t t a n No. 4 Homestead Fox Isabella Martinka Meigs B i r d No. 3 Dean Muskingum
Coal Mine
Table I I .
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150
DESULFURIZATION
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COAL
FLOAT - SINK SEPARATION (FLOAT FRACTION) MEYERS PROCESS
Figure 3.
Trace element removal data
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
11.
HAMERSMA
E T
AL.
Meyers Process for Desulfurization
151
I t c a n be e a s i l y s e e n f r o m T a b l e I I t h a t t h e r e i s a w i d e band o f r a t e c o n s t a n t s r a t h e r e v e n l y s p r e a d o v e r a f a c t o r o f a p p r o x i m a t e l y 30. The K o p p e r s t o n No. 2 a n d H a r r i s N o s . 1 and 2 c o a l s r e a c t more r a p i d l y t h a n t h e s l o w e s t c o a l s (Dean a n d Muskingum) b y a f a c t o r o f a b o u t 30. T h u s , i t i s a p p a r e n t t h a t r e a l a n d s i g n i f i c a n t r a t e d i f f e r e n c e s do e x i s t b e t w e e n p y r i t e i n various coals. C h a r a c t e r i s t i c s o f c o a l such as pore s t r u c t u r e , s i z e a n d s h a p e d i s t r i b u t i o n o f p y r i t e , e t c . may be t h e p r i m a r y f a c t o r s a f f e c t i n g t h e r a t e c o n s t a n t as r e f l e c t e d i n t h e observed band o f v a l u e s f o u n d f o r t h e r a t e s g i v e n i n T a b l e I I .
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T r a c e Element Removals B e c a u s e b o t h c h e m i c a l l e a c h i n g and p h y s i c a l c l e a n i n g p r o c e s s e s c a n remove p o t e n t i a l l y h a r m f u l t r a c e e l e m e n t s f r o m c o a l e i t h e r by l e a c h i n g o r by p h y s i c a l p a r t i t i o n i n g , 50 c o a l s a m p l e s have been a n a l y z e d i n d u p l i c a t e o r t r i p l i c a t e t o determine t h e e x t e n t o f t h e r e m o v a l , i f a n y , o f 18 e l e m e n t s o f i n t e r e s t t o t h e E n v i r o n m e n t a l P r o t e c t i o n A g e n c y . The s a m p l e s i n c l u d e d 20 a s r e c e i v e d , 20 c h e m i c a l l y l e a c h e d , and 10 f l o a t - s i n k t r e a t e d c o a l s a m p l e s . The r e s u l t s a r e shown f o r 12 e l e m e n t s i n F i g u r e 3 i n cumulative fashion. The e x t r a c t i o n p r o c e d u r e was a s i n T a b l e I . S i x e l e m e n t s , B, B e , Hg, Sb, Se, and Sn y i e l d e d n e g a t i v e o r i n c o n c l u s i v e r e s u l t s because of low l e v e l s o r a n a l y s i s d i f f i c u l t i e s and t h u s a r e n o t p l o t t e d . A l t h o u g h t h e r e s u l t s v a r i e d g r e a t l y f r o m c o a l t o c o a l w i t h r e s p e c t t o t h e e l e m e n t s e x t r a c t e d and t h e d e g r e e o f e x t r a c t i o n , some g e n e r a l c o n c l u s i o n s c a n be r e a c h e d . (1) A s , C d , Mn, N i , P b , and Zn a r e removed t o a s i g n i f i c a n t l y g r e a t e r e x t e n t by t h e Meyers p r o c e s s (2) F and L i a r e p a r t i t i o n e d t o a g r e a t e r e x t e n t by p h y s i c a l separation procedures. (3) Ag a n d Cu a r e removed w i t h a s l i g h t p r e f e r e n c e f o r f l o a t - s i n k separation (4) C r a n d V a r e removed by b o t h p r o c e s s e s w i t h e q u a l success. The e f f e c t i v e r e m o v a l o f A s , C d , C r , N i , P b , and Zn f r o m t h e c o a l b y t h e M e y e r s p r o c e s s i s e s p e c i a l l y n o t e w o r t h y a s t h e s e compounds a r e c o n c e n t r a t e d ( a l o n g w i t h Se) i n t h e f i n e p a r t i c u l a t e s e m i t t e d f r o m c o a l - f i r e d power p l a n t s . This f i n e p a r t i c u l a t e matter passes through conventional f l y - a s h c o n t r o l devices.
Literature Cited
1. Meyers, R.A., Hamersma, J.W., Land, J.S., Kraft, M.L., Science, (1972),177,1187. 2. Meyers, R.A., "Removal of Pyritic Sulfur from Coal Using Solutions Containing Ferric Ions," U.S. Patent 3768988, 1973. 3. Koutsoukos, E.P., Kraft, M.L., Orsini, R.A., Meyers, R.A., Santy, M.J., Van Nice, L.J., "Final Report Program for BenchScale Development of Processes for the Chemical Extraction of
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.
152 4. 5.
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6. 7. 8.
9. 10.
COAL DESULFURIZATION
Sulfur from Coal," Environ. Prot. Technol. Ser., (May 1976), EPA-600/2-76-143a. Hamersma, J.W., Koutsoukos, E.P., Kraft, M.L., Meyers, R.A., Ogle, G.J., Van Nice, L.J., "Chemical Desulfurization of Coal: Report of Bench-Scale Developments, Volumes 1 and 2," Environ. Prot. Technol. Ser., (February 1973),EPA-R2-173a. Magee, E.M., "Evaluation of Pollution Control in Fossil Fuel Conversion Processes, Coal Treatment: Section 1. Meyers Process," Environ. Prot. Technol. Ser., (September 1975), EPA-650/2-74-009k. Nekervis, W.F., Hensley, E.F., "Conceptual Design of a Commercial Scale Plant for Chemical Desulfurization of Coal," Environ. Prot. Technol. Ser. (September 1975), EPA-600/2-75-051. Tek, M. Rasin, "Coal Beneficiation," in Evaluation of Coal Conversion Processes, (1974) PB-234202. U.S. Environmental Protection Agency, Office of Research and Development, Washington, DC, "Applicability of the Meyers Process for Chemical Desulfurization of Coal: Initial Survey of Fifteen Coals," by J.W. Hamersma et al, Systems Group of TRW, Inc., Redondo Beach, CA. (April 1974), EPA-650/2-74-025, Contract No. 68-02-0647. Hamersma, J.W., Kraft, M.L., "Applicability of the Meyers Process for Chemical Desulfurization of Coal: Survey of Thirty-Five Coals," Environ. Prot. Technol. Ser., (September 1975), EPA-650/2-74-025a. Deurbrouck, A.W., "Sulfur Reduction Potential of Coals of the United States," U.S. Bur. Mines Rep. Invest. (1972), 7633.
In Coal Desulfurization; Wheelock, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.