14 Major, Minor, and Trace Elements in the
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Liquid Product and Solid Residue from Catalytic Hydrogenation of Coals P. H. GIVEN, R. N. MILLER, N. SUHR, and W. SPACKMAN College of Earth and Mineral Sciences, Pennsylvania State University, University Park, Penn. 16802
Approximate contents of 14 minor and trace elements in oils produced from three coals by the catalytic hydrogenation process of Gulf Research and Development Co. were determined by emission spectroscopy. The results were compared with corresponding data for the original coals and the solid residues from the process. The contents of ash, sulfur, vanadium, lead, and copper are near or below the limits specified for an oil to be fired directly in a gas turbine while sodium and probably calcium are too high. Titanium appears to be somewhat enriched in the oils analyzed relative to other elements, suggesting its presence in organometallic complexes.
' " J ^ h e a s h content a n d trace element d i s t r i b u t i o n i n oils p r o d u c e d f r o m A
c o a l a r e of c o n c e r n f o r t w o different r e a s o n s — t h e y b e a r o n p o s s i b l e
e n v i r o n m e n t a l h a z a r d s f r o m t h e use of t h e o i l a n d t h e y d e t e r m i n e t h e s u i t a b i l i t y of t h e o i l f o r firing i n gas t u r b i n e s . S o m e trace element a n a l y ses of oils p r o d u c e d b y t h e c a t a l y t i c l i q u e f a c t i o n of three coals are r e p o r t e d , together w i t h analyses of t h e s o l i d residues f r o m t h e process. T h e d a t a are n e i t h e r c o m p r e h e n s i v e n o r p a r t i c u l a r l y a c c u r a t e a n d are offered at this t i m e because, i n t h e absence of better i n f o r m a t i o n f r o m other l a b o r a t o r i e s , t h e y seem to b e of some interest. Procedure T h e samples of o i l a n d r e s i d u e w e r e p r o d u c e d i n the course of t h e c o o p e r a t i v e r e s e a r c h project b e t w e e n w o r k e r s at this u n i v e r s i t y a n d at 188 Babu; Trace Elements in Fuel Advances in Chemistry; American Chemical Society: Washington, DC, 1975.
14.
Catalytic
GIVEN E T A L .
Hydrogénation
of
189
Coals
G u l f R e s e a r c h a n d D e v e l o p m e n t C o . T w o of the coals w e r e processed i n the G u l f continuous flow reactor, f e d at t h e r a t e of a b o u t 1.5 k g c o a l / h r for 1 5 - 1 8 hrs. T h e t h i r d c o a l was processed
in a conventional batch
a u t o c l a v e r u n . I n a l l three r u n s , the c o a l was processed at a b o u t 4 0 0 ° C a n d 3000 p s i pressure of h y d r o g e n u s i n g a p r o p r i e t a r y catalyst. I n the c o n t i n u o u s r u n s , d i s t i l l a t e f r o m p r e v i o u s e x p e r i m e n t s w a s u s e d as v e h i c l e
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w h i l e i n the autoclave experiment, partly hydrogenated was u s e d .
T h e v e h i c l e - t o - c o a l r a t i o was 2 : 1 .
phenanthrene
I n e a c h case the r e a c t i o n
p r o d u c t s w e r e filtered o n a steam-heated B u c h n e r f u n n e l . T h e oils w e r e d i s t i l l e d at 1 m m pressure u n t i l a b o u t one t h i r d r e m a i n e d i n the pot.
T h e u n d i s t i l l e d r e s i d u e , the s o l i d r e s i d u e f r o m the
r e a c t i o n ( c a t a l y s t pellets r e m o v e d b y h a n d ) , a n d the o r i g i n a l c o a l w e r e a s h e d i n a n o x y g e n p l a s m a w i t h o u t external h e a t i n g , u s i n g a l o w t e m p e r a t u r e asher f r o m I n t e r n a t i o n a l P l a s m a C o r p . T h e ashes w e r e a n a l y z e d b y emission spectroscopy u s i n g a d.c. a r c a n d a J a r r e l l - A s h W a d s w o r t h s p e c t r o g r a p h . A v i s u a l c o m p a r i s o n of l i n e intensities w i t h s t a n d a r d r o c k samples e s t a b l i s h e d the a p p r o x i m a t e elem e n t a l concentrations.
B a s e d o n experience, t h e t r u e content of
any
e l e m e n t is most p r o b a b l y w i t h i n the range 2 to 0.5 X t h e stated v a l u e . T h e coals w e r e c o l l e c t e d i n the field b y W . S p a c k m a n a n d his associates.
F u l l pétrographie, p r o x i m a t e , a n d u l t i m a t e analyses are
avail-
able, b u t i t does not seem a p p r o p r i a t e to r e p r o d u c e the f u l l d a t a here. T h e m i n e r a l m a t t e r contents r e p o r t e d b e l o w w e r e d e t e r m i n e d b y a c i d demineralization Results and
(I).
Discussion
T h e results are s h o w n i n T a b l e s I, I I , a n d I I I . T h e m a j o r elements i n c o a l a n d i n the d e r i v e d p r o d u c t s are, i n o r d e r of d e c r e a s i n g a b u n d a n c e i n the m a t e r i a l s s t u d i e d , s i l i c o n , a l u m i n u m , c a l c i u m , i r o n , a n d nesium.
mag-
W i t h the m i n o r a n d trace elements, t h e d e t e c t i o n l i m i t s v a r y
w i t h the ash content of e a c h t y p e of m a t e r i a l ; a b o u t 1-5 p p m for the coals a n d residues a n d 1-3
p p b for the oils.
T h e elements
thallium,
b i s m u t h , g e r m a n i u m , a n d g a l l i u m w e r e sought b u t not detected. C l e a r l y the o i l is a m u c h cleaner f u e l t h a n the o r i g i n a l c o a l , f r o m the p o i n t of v i e w either of the e n v i r o n m e n t a l i s t or of the p l a n t engineer concerned
w i t h f o u l i n g of
steam a n d superheater tubes.
T h e sulfur
contents of the oils are 0 . 1 - 0 . 2 % , w h i c h is a c c e p t a b l e , b u t the n i t r o g e n contents are a b o u t 0 . 6 % , w h i c h m a y cause u n d e s i r e d N O
x
emissions.
S o m e of the m o r e toxic elements, ( m e r c u r y , s e l e n i u m , fluorine, a n d c a d m i u m ) h a v e not yet b e e n d e t e r m i n e d i n o i l . It is not clear w h a t w i l l b e d o n e w i t h the s o l i d r e s i d u e : w h e t h e r i t w i l l b e d i s p o s e d of as w a s t e or w h e t h e r its s m a l l c a r b o n content, t y p i c a l l y 2 0 - 5 0 % d e p e n d i n g o n t h e
Babu; Trace Elements in Fuel Advances in Chemistry; American Chemical Society: Washington, DC, 1975.
190
TRACE
Table I.
Feed coal S o l i d residue Oil
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IN F U E L
Concentration of Minor and Trace Elements
Β
Co
V
Ni
Ti
Mo
12 25 0.15
25 12 0.12
12 25 0.06
12 5 0.15
75 150 5
tr. 25 0.08
«Minerai matter, dry basis, content of oil, 150 ppm. Table II.
Feed coal S o l i d residue Oil
ELEMENTS
12.9%.
High Vol. B . Total S,
0.52
(S
pyr
0.13).
Ash
Concentration of Minor and Trace Elements from
Β
Co
V
Ni
Ti
Mo
25 150 0.12
12 40 0.01
50 150 0.25
25 80 0.08
400 1100 6
12 40 0.01
° Mineral matter, 2 5 % . High Vol. A . Total S, 5 . 2 % (Spyr 4.0). Ash content of oil ppm.
250
Table III.
Feed coal S o l i d residue Oil a
90
Mineral matter, ppm.
Concentration of Minor and Trace Elements
Β
Co
V
Ni
Ti
Mo
7 40 0.03
4 20 0.004
4 40 0.004
4 20 0.03
450 240 0.5
4 20 b
7.3%.
High Vol. A . Total S,
3.9%
(S
pyr
0.13).
Ash content of oil,
m i n e r a l m a t t e r content of t h e c o a l , w i l l b e u s e d f o r gasification o r c o m b u s t i o n . T h e l e a c h a b i l i t y o f t o x i c elements s h o u l d b e s t u d i e d . O n e i m p o r t a n t p o t e n t i a l u s e f o r l o w s u l f u r fuels oils f r o m c o a l is firing
i n gas t u r b i n e s f o r e l e c t r i c i t y generation. A p a r t i c u l a r l y c l e a n f u e l
is n e e d e d f o r this p u r p o s e , to a v o i d d a m a g i n g t h e t u r b i n e b l a d e s . A c c o r d i n g to F . R o b s o n ( 2 ) , d e s i r e d specifications a r e : ash, 100 p p m ; S, < 1.3%; ppm;
Na +
K , < 0.2-0.6 p p m ; V , 0 . 1 - 0 . 2 p p m ; P b , 0.1 p p m ; C a , 0.1
a n d C u , 0.02 p p m . I t w i l l b e seen t h a t t h e oils a n a l y z e d m e e t
m a n y of these specifications.
T h e c h i e f exceptions
a r e t h e contents o f
sodium and calcium. A final p o i n t of interest is that i n t w o of t h e oils, t i t a n i u m is c o n s i d e r a b l y e n r i c h e d r e l a t i v e to other elements, c o m p a r e d w i t h t h e ratios i n the o r i g i n a l c o a l . A p l a u s i b l e e x p l a n a t i o n is t h a t t h e t i t a n i u m is present i n o r g a n o m e t a l l i c c o m b i n a t i o n i n these oils. Acknowledgments T h e authors are i n d e b t e d to t h e R A N N
D i v i s i o n of t h e N a t i o n a l
S c i e n c e F o u n d a t i o n f o r s u p p o r t of t h e i r w o r k ( G r a n t N o . G I - 3 8 9 7 4 ) a n d
Babu; Trace Elements in Fuel Advances in Chemistry; American Chemical Society: Washington, DC, 1975.
14.
Catalytic
GIVEN E T A L .
Hydrogénation
of
from the Β Seam, K i n g Mine, U t a h , PSOC-239 ( p p m ) Na 5000 1000 5
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6
Pb 6 b
0.02
191
Coals e
Zn
Mn
Cr
Cu
Cd
Be
25 50 0.12
12 25 0.05
25 25 0.05
12 25 0.02
0.2 0.5 —
0.4 0.8 0.0004
Not detected
Lower Dekoven Seam, W i l l Scarlett Mine, 111., PSOC-284 ( p p m ) Na 2500 8000 2.5 b
Pb 6 b 6
Zn
Mn
Cr
Cu
125 — 0.12
125 300 0.12
25 80 0.12
25 90 0.03
Cd
Be
4 4 —
0.8 2 0.01
Not detected
from the Mining C i t y Seam, Jerry Mine, K y . , PSOC-221 ( p p m ) Na 150 800 0.9 6
a
Zn
Pb b b b
b 100 0.05
a
Mn
Cr
Cu
Cd
Be
4 80 0.05