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SAMPLE PREPARATION FOR, AND CURRENT STATUS OF,

THE ARGONNE PREMIUM COAL SAMPLE PROGRAM*

Karl S. Vorres

Chemistry Division, Building 211

Argonne National Laboratory

Argonne, IL 60439

ABSTRACT

The Argonne Premium Coal Sample Program includes eight coals

(Upper Freeport, Wyodak-Anderson, Illinois #6, Pittsburgh,

Pocahontas #3, Utah Blind Canyon, Lewiston-Stockton and Beulah-

Zap seams) chosen to provide a range of chemical composition, in-

cluding sulfur content, maceral content and geographic distribu-

tion. One of the purposes is to provide a set of pristine

samples for comparison and correlation. They have been collected

in ton-sized batches and processed to provide a minimal exposure

to oxygen, thoroughly mixed, and packaged in borosilicate glass

ampoules containing either 5 grams of -100 mesh or 10 grams of

-20 mesh material. This material has been analyzed by a number

of laboratories, including a round robin with Commercial Testing

and Engineering Co. Further data are being added to an analyti-

cal data base as they become available. Over 190 shipments have

been made to over 110 different users. Research is currently

being carried out in almost every area of coal science with these

samples.

• This work was supported by the Office of Basic Energy Sciences,

Division of Chemical Sciences, U. S. Department of Energy,

under contract number W-31-109-ENG-38.

IN T R 0 DUCTION

Goals:

The Premium Coal Sample Program was initiated at the Argonne Na-

tional Laboratory about five years ago to provide the basic coal

research community with a small number of carefully selected,

collected, processed packaged and analyzed samples. The tech-

niques of mixing, sealing and storage are intended to provide a

large number of uniform samples that will be stable over a long

time, and will permit reproducible experiments to be carried out

at different times and laboratories.

Selection of Samples:

The coals included in the program were selected to give a range

of composition in terms of the carbon, sulfur, hydrogen and

oxygen contents. A cluster analysis involving data from over 200

channel samples in the existing Pennsylvania State University

database was used to provide eight ranges of composition, from

which the chemical composition characteristics of the eight

samples were chosen. In addition they were selected to give a

range of rank, geographical distribution, and maceral content.

In the order collected, these eight coals are:

Seam

Upper Freeport

Wyodak-Anderson

Illinois

Pittsburgh

Pocahontas # 3

Utah Blind Canyon

Lewiston-Stockton

Beulah-Zap

origin

PA

WY

IL

PA

VA

UT

wv

ND

Rank

MVB

SUB

HVB

HVB

LVB

HVB

HVB

LIG

The abbreviations are: LIG = lignite, SUB = subbituminous, HVB =

high volatile bituminous, MVB = medium volatile bituminous, LVB =

low volatile bituminous.

Collection:

Details of the procedures for collection have been given in ear-

lier reports (1-8). In brief, the samples from underground mines

were collected from freshly exposed blocks of coal, the thickness

of the seam. Typical samples were about 1 1/2 tons. For thick

underground seams (#3 , 4,5,6 , 7) , the 55 gallon stainless steel

drums were taken to the seam face,,and representative samples

were placed directly into the drums. For the thinner seam (#1)

the sample was taken to the surface in double plastic bags. Sur-

face mine samples (#2 and 8) were obtained from core samples.

Processing and Packaging:

At the surface the drums were purged with enough argon to reduce

the oxygen content to 100 ppm, and quickly transported in a

temperature-controlled semi-trailer to Argonne National

Laboratory (ANL) for processing. AT ANL, the drums were weighed,

placed into airlocks, purged, the contents were crushed, pul-

verized to -20 mesh, thoroughly mixed, and the contents were

packaged. Half the batch was reground to -100^ mesh,^ and then

packaged. Packaging included placing about 80% of the coal in

carboys of borosilicate glass for long term storage. The balance

went into amber borosilicate glass ampoules of 10 grams of -

mesh or 5 grams of -100 mesh material. The oxygen content of the

packaging facility was maintained below 100 ppm at all times, and

was typically about 30 ppm.

CURRENT STATUS

Inventory - Long Term Supply:

The ampoules and carboys are kept in a dark air-conditioned

storage room. About 10,000 of the 5 gram ampoules and 5,000 of

the 10 gram ampoules were made for each sample. Initially about

120,000 samples were placed in storage with about 550 of the 5

gallon carboys. As shipments deplete the inventory, then carboys

can be placed in the packaging facility and additional ampoules

filled and sealed to replenish the inventory. The current demand

is such that the supply of ampoules should not need replenishing

for another 6 years. The Illinois #6 sample is the most fre-

quently requested.

USGS Circulars - Geology and Geography:

In addition, the United States Geological Survey, which super-

vised the collection of the samples, is preparing a series of

U S G S Circulars, which will summarize the geological and

geographical information of general interest about these samples.

These may be obtained directly from the U S G S.

Newsletter:

A newsletter has been initiated to provide current information of

value to all recipients of the samples. The quarterly publica-

tion gave the contents of this symposium, and announced the

development of a bibliography of references to the use of the Ar-

gonne Premium Coal Samples. All recipients of samples are asked

to provide references to reports, journal articles and other

public information so that this information may be shared with

other investigators.

Types of Research Work

The types of research being done with the samples are about as

diverse as the research being done on coal. The symposia that

follows will give a representative sample, but certainly does not

include all of the work that is being done. The major fields in-

clude: structural studies, determination of the functional

groups qualitatively and quantitatively in the coal, coalifica-

tion, pyrolysis, liquefaction and gasification, sulfur removal,

new methods of analysis and others.

Symposia:

This symposium is the second in a series devoted to research done

with the Argonne Premium Coal Samples. The first, held in New

Orleans in September, 1987 had 23 papers on a variety of topics.

The organization this year is based on the subject matter of the

individual papers. The range of work is such that a number of

papers are finding their way into symposia on topics of special

interest such as coal liquefaction, and this trend will probably

continue.

Future Activities:

The APCSP will continue to provide samples and information about

these samples to the users. It is planned to provide a data

handbook to give in one document the most frequently requested

information. This will include the results of the analytical

work that is reported to the author, and special studies which

have been arranged to provide for a reasonably complete set of

information.

Further, individual studies may be initiated to respond to cer-

tain findings of potential interest to the user community. The

observation of increased concentrations of methane and carbon

dioxide in some of the ampoules led to speculation that anaerobic

bacteria may be present with the samples. An effort is underway

I

to culture bacteria from samples of coal from each of the

batches. The results of this effort will be described at a fu-

ture meeting.

2.

3.

4.

5.

6.

7.

8.

REFERENCES

Vorres, K. S., Preprints of the Fuel Chem. Div., Am. Chem.

SOC., 32(4) 221-6(1987), ibid., 32(1) 492(1987) (with S. K.

Janikowski), x ( 3 ) , 304-9 (1986) (with S. K. Janikowski), ibid., 3 0 ( 4 ) , 193-6(1985), ibid. , a ( 6 ) 230-3(1984).

Vorres, K. S. , Proc. , Fourth Annual Pittsburgh Coal Conf.,

pp. 160-5, Sept 28-Oct. 2, 1987. Univ. of Pittsburgh.

Vorres, K. S., 1981 Intl. Conf. on Coal Science, pp. 937-40,

Elsevier Science Publishers, BV., Amsterdam, 1987, ed. J. A.

Moulijn, €I.A. G. Chermin and K. A. Nater.

Vorres, K. S., 1985 Intl. Conf. on Coal Science, Interna-

tional Energy Agency, pp 640, October 28-31, Sydney,

Australia.

Vorres, K. S. SME-AIME Annual Meeting, New York, February

1985, Paper #85-12.

Vorres, K. S., J. Coal Quality, 3(4), 31 (1984).

Vorres, K. S., Proc. of Workshop on Standards in Biomass for

Energy and Chemicals, National Bureau of Standards,

Gaithersburg, MD, 1-3 Aug. 1984, pp. 27-33. Ed. T. A. Milne,

Anon. ,^ Chem. Engr. News,^ =(1)24(1984).

SERI/CP-234-2506.

ACKNOWLEDGMENTS

The author gratefully acknowledges the support of the Office of

Basic Energy Sciences, Division of Chemical Sciences of the U. S.

Department of Energy. The efforts of many individuals who con-

tributed at each stage of the program is deeply appreciated.

Among these is the glass-blowing done by Joe Gregar..

KINETICS OF VACUUM DRYING AND REHYDRATION IN NITROGEN

OF COALS FROM

THE ARGONNE PREMIUM COAL SAMPLE PROGRAM*

Karl s. Vorres and Roger Kolman

Chemistry Division, Building 211

Argonne National Laboratory

Argonne, IL 60439

ABSTRACT

The kinetics of vacuum drying and rehydration in nitrogen of

Wyodak-Anderson subbituminous, and Illinois #6 and Utah Blind

Canyon high volatile bituminous coal samples have been studied at

room temperature. Some samples were oxidized at room tempera-

ture. Several cycles of drying and rehydration were carried out

on the same sample. The drying rates depended on particle size

and moisture content of the sample. Several different mechanisms

of moisture loss and rehydration were indicated by the kinetic

data. The mechanism depended on particle size, coal rank, and

degree of oxidation.

• This work was supported by the Office of Basic Energy Sciences,

Division of Chemical Sciences, U. S. Department of Energy,

under contract number W-31-109-ENG-38.

INTRODUCTION

Drying and rehydration of a porous material can give some insight

into the surface properties and the internal structure of the

material. The rate of moisture removal or replacement will

depend upon the coal surface, the macromolecular network of the

coal particles and the structure of the pores through which the

moisture flows.

An earlier study (1) reported the results of drying and rehydra-

tion studies on Illinois #6 Argonne Premium Coal Samples. The

work involved different particle sizes and indicated that the

mechanisms of drying and rehydration changed, depending on the

coal particle size. The samples were fresh and aged, which also

affected the results.

In general four mechanisms were observed (1). One involves a

diffusion limited’process of migration through a uniform barrier,

and is observed with a parabolic curve. This is also referred to

as Fickian diffusion. A second mechanism, obeying first order

kinetics, similar to radioactive decay, would imply that the

probability of a given water molecule being removed or adsorbed

was a random probability event, and that all surface sites from

which the water molecules depart or the water molecules in the

sample were apparently equivalent. The third mechanism gives a

plot following an adsorption isotherm curve. The mechanism here

depends on the degree of surface coverage. A fourth mechanism,

sometimes associated with the parabolic curve, is a linear

mechanism implying a uniform barrier for diffusion.

The equation for the diffusion through a growing uniform barrier

is:

where W is the mass change, k is a rate constant and t is the

elapsed time.

The equation for the first order kinetics is:

A characteristic half-time or half-life is associated with this

reaction such that half the reaction is over in the half life,

3/4 is over in two half lives, 7/8 is over in three half lives

etc.

For the adsorption or desorption reaction, the equation is:

A characteristic half time or half life is also associated with

this reaction. The half time is the time for half of the ob-

served change to take place. Then 2/3 of the reaction takes

place in two half times, 3/4 takes place in three half times, 4/

takes place in four half times etc.

The equation for the linear reaction is:

This study extended the earlier work and involved examination of

the drying and rehydration behavior of a lower rank Wyodak-

Anderson sample, and a similar rank (but lower moisture content)

sample from a different coal basin (Utah Blind Canyon seam).

W2 = kt

log W = k t

W = k(t/t + 1)

W = kt

APPARATUS, MATERIAL AND PROCEDURES

The studies were carried out with an Ainsworth recording

thermobalance (described earlier (1)). The samples were weighed

on a quartz pan and suspended from the balance. A quartz en-

velope was placed around the sample to control the gaseous en-

vironment. A water bath was placed around the sample to provide

for temperature control to about lo C. Initially the gas atmos-

phere was removed with a vacuum pump for dehydration. After

dehydration, the samples were rehydrated by stopping the vacuum

pump, backfilling with nitrogen, removing the quartz envelope,

inserting an ice cube, re-evacuating to remove air, and backfill-

ing with nitrogen. The ice cube was melted with warm water, and

the water bath was replaced. The cycle was repeated by removing

the quartz envelope and water, drying the envelope and replacing

it and the water bath. From two to four cycles of dehydration

and rehydration with the same sample were obtained in this way.

Sample weights varied between 0.100 and 1.112 grams. The weights

used were :

IL # 6 Block

IL # 6 -20 mesh

IL # 6 -100 mesh

Wyodak -20 mesh

UT Blind Canyon

1.112 grams

0.100 gram

0.239 gram

0.100 gram

-100 mesh 0.346 gram

The dehydration of the -20 mesh material is unique for the

samples which have been studied. The initial loss was very low

due to the small amount of moisture in the sample at the start.

Subsequent runs followed a combination of linear and parabolic

segments. The mass change for the initial linear segments in-

creased from cycle 2 to cycle 3. The surface of this sample was

oxidized which would provide a number of hydrophilic sites, in

contrast to the hydrophobic sites to be expected on pristine

samples. The moisture loss is significantly greater than the

ASTM moisture value, and a large part takes place in the initial

linear segment. This suggests that some moisture may be caught

in the interstices of the particles. The ASTM moisture should be

the sum of the moisture held in pores and in the macromolecular

network. The pore moisture can be approximated by subtracting

the amount taken up during the parabolic portion and the final

linear part from the ASTM moisture. The amount in excess of the

ASTM moisture may approximate the amount held in the interstices

between the particles. The interstitial water is expected to be

released quickly and following the linear mechanism.

The rehydration of the -20 mesh material was observed to largely

follow the adsorption mechanism.

The dehydration of the -100 mesh sample followed the desorption

model. The sample had initially been equilibrated with distilled

water at room temperature and lost about 11 % moisture. The sub-

sequent rehydration allowed only about 8 % moisture (the ASTM

moisture) and that was lost in the following dehydration.

The rehydration curves initially followed an adsorption model and

then showed evidence of multilayer formation. However, the sub-

sequent dehydration did not show evidence of separate layers

being desorbed.

A comparison of the rates of the reactions showed that the block

is the slowest to change mass per gram. The initial rate for the

-20 mesh reflects the low initial moisture content of that

sample. The intermediate rate was indicated for the -100 mesh

material, and the fastest rate for the oxidized -20 mesh material

after the initial dehydration. This comparison is valid for both

the dehydration and the rehydration mechanisms.

The dehydration data for the Wyodak sample indicated a desorption

model.

The rehydration of the Wyodak sample indicated the formation of

several layers of^ moisture following an initial layer of moisture

adsorption. Nevertheless, the subsequent dehydration did not

show any significant or comparable deviation from the normal

desorption curve. The mass loss on the second dehydration indi-

cated that only about 15 % moisture was lost, compared to the 28

% moisture determined by the ASTM method.

The dehydration of the Utah Blind Canyon sample followed the

desorption model. The rehydration of the sample also followed

the adsorption curve. There was no evidence of multilayer forma-

tion.

I

CONCLUSIONS

The mechanisms of dehydration and rehydration vary depending on

the sample size and history. The behavior of an individual par-

ticle is best approximated by the block of Illinois #6 which in-

dicated the desorption mechanism for dehydration and the

parabolic mechanism or Fickian diffusion for rehydration. In

general pristine samples followed an adsorption or desorption

mechanism. Aged or oxidized samples showed combinations of

linear and parabolic mechanisms which probably reflect a change

in the surface properties in going from a hydrophobic behavior

for the more pristine to hydrophilic for the more aged or

oxidized material. Multilayer adsorption was observed on the

lower rank materials which implies that the functional groups

present on the surface facilitate this type of phenomenon.

ACKNOWLEDGMENTS

The authors gratefully acknowledge the support of the Office of

Basic Energy Sciences, Chemical Sciences Division, and the Ar-

gonne National Laboratory Division of Educational Programs. Tim

Griswold helped obtain the data and do some of the data reduc-

tion. The glassblowing by Joe Gregar was extremely helpful.

Useful discussions with Anthony Fraioli are also acknowledged.

REFERENCE

1. Vorres, X. S., Kolman, R. and Griswold, T., Preprints, Fuel

Chem. Div., Am. Chem. SOC., =(2), 333(1988)

1. UF

MECHANISMS FOR THE DEHYDRATION AND REHYDRATION OF COAL SAMPLES.

Sample Dehydration Rehydration

Illinois #6 Block Desorption

-20 mesh L - P - L

-100 mesh Desorption

Parabolic

Adsorption

Adsorption

Wyodak-Anderson -20 mesh Desorption Adsorption

Utah Blind Canyon -100 mesh Desorption Adsorption

Vacuum Dehydration I L e 6 -20 Mesh 22 C. IL20030. 1 2 m L 210 zoo 190 160 I 160 I S 0 6 ;;:

'::

P 10

120 110

n BO 60 50 40 30 20 10 0 0 4 B 12 16 20 24 28 32 36 <O Time Crnl")

Figure 3.

Rehydration o f I L f t 6 i n N2, - 2 0 Mesh 22 C. IL2003, I 2 W L 100

90

P

I

BO

70

Figure 4.

V a c. Dehydration o f I L #6 - 1 0 0 M e s h

2 2 c., ILIOIID. l 1 W L 1 2 0

1 1 0 100

90

8 p 70 "

l - 0 4

2 0 "

lo '

Figure 5.

R e h y d r a t i o n of I L #6 -100 Mesh i n N 2

23 C. ILIOIlR, I1RG4L 90

i;

b

Figure 6.

Dehydration o f UT -100 M e s h U T l O O l D , , 3 4 6 gn. 21 C, UT

50

150 300 450 600 750 900 , T l r n CmlnJ

Figure 9.

Rehydration of UT -100 M e s h Ur100711. 21 C. , 3 4 6 m. UR1& 45

4 0

35

0 150 300 450 600 750 900 1050 1200 1350 TlmP Crnl")

Figure 10.

STRUCTURAL GROUP ANALYSIS OF ARGONNE PREMIUM COALS BY FTIR SPECTROSCOPY

K.A. Martin S.S. Chao

I n s t i t u t e of Gas Technology Chicago, Illinois 60616

INTRODUCTION

I n f r a r e d spectroscopy is a w e l l - e s t a b l i s h e d method of c o a l c h a r a c t e r i z a t i o n (1-12). Aspects of c o a l s t r u c t u r e such as f u n c t i o n a l groups and hydrogen- bonding (11) and changes in s t r u c t u r e d u r i n g p y r o l y s i s ( 6 , 7 ) and o x i d a t i o n (4,5,9,10) have been d e s c r i b e d through i n f r a r e d a n a l y s i s and r e l a t e d t o macromolecular processes. h p a r t i c u l a r , P a i n t e r e t. al. ( 2 ) , have proposed an FTIR procedure f o r a f a i r l y e x h a u s t i v e a n a l y s i s of c o a l f u n c t i o n a l groups. Many of t h e s e s u g g e s t i o n s a r e i n c o r p o r a t e d i n t o t h e p r e s e n t study f o r t h e development of a f u n c t i o n a l group a n a l y s i s d a t a b a s e f o r a s e t of s t a n d a r d c o a l s.

EXPERIMENTAL

Eight Argonne premium c o a l samples were s t u d i e d : Pennsylvania Upper F r e e p o r t , Wyodak, I l l i n o i s #6, P i t t s b u r g h #8, Pocahontas 1 3 , Utah Blind Canyon, West V i r g i n i a Stockton-Lewiston, and Beulah-Zap. Each ampoule of -100 mesh c o a l was mixed, opened, and t h e c o n t e n t s d r i e d in a vacuum oven a t 40°C f o r two hours. The d r i e d samples were s t o r e d under vacuum u n t i l used. D i f f u s e r e f l e c t a n c e i n f r a r e d (DRIFT) s p e c t r a were ob ained on n e a t d r i e d samples w i t h a Nicolet 60SXB FTIR w i t h 500 s c a n s at 4 cm-' r e s o l u t i o n. KBr p e l l e t s were a l s o p r e a r e d (about 0.3% c o a l by weight) and s p e c t r a c o l l e c t e d with 128 s c a n s a t 4 cm-' r e s o l u t i o n. Carbon, hydrogen and n i t r o g e n a n a l y s e s were performed with a LECO CHN-600 a n a l y z e r , and oxygen analyses were performed on a Carlo ERBA 1106 elemental analyzer. The low temperature ash of each c o a l was obtained w i t h 0.5 g sample i n an I n t e r n a t i o n a l Plasma Machine l l O l B a t 130 w a t t s f o r s e v e r a l days. Another 0.5 g of each c o a l was a c e t y l a t e d by h e a t i n g t h e c o a l a t 100°C i n a 2:l mixture of p y r i d i n e and a c e t i c anhydride f o r e i g h t hours followed by f i l t e r i n g and vacuum drying.

RESULTS AND DISCUSSION

Each of t h e two sampling methods employed h e r e , DRIFT and KBr p e l l e t s , have advantages and drawbacks in c o a l a n a l y s i s. to-noise r a t i o , b u t is very s e n s i t i v e t o some i n f r a r e d bands which do not appear well in t r a n s m i s s i o n s p e c t r a. Figure 1 compares t h e C-H s t r e t c h i n g region of t h e Blind Canyon c o a l from DRIFT and K B r p e l l e t s p e c t r a. Absorbance u n i t s a r e used r a t h e r than Kubelka-Munk u n i t s because t h e l a t t e r r e s u l t in i n t e n s i t i e s too weak t o r e s o l v e well. A weak band a t 2732 0 m - l is apparent in t h e DRIFT spectrum, b u t b a r e l y observed in t h e t r a n s m i s s i o n spectrum. The r e l a t i v e i n t e n s i t i e s of t h e C-H bands a l s o change, with t h e symmetric and asymmetric CH3 modes enhanced i n t h e DRIFT spectrum. DRIFT^ is^ e s p e c i a l l y u s e f u l because c o a l can be sampled without an i n t e r f e r i n g m a t r i x , which is important in d e t e r m i n a t i o n s of OH and water content. KBr p e l l e t s , on t h e o t h e r hand, o f f e r t h e advantages of a high signal-to-noise r a t i o and b e t t e r

DRIFT s u f f e r s from a lower s i g n a l -

t h e e i g h t c o a l s between 1700 and 1500 cm-' a f t e r s u b t r a c t i o n of t h e low- temperature a s h spectrum. It c a n be s e e n t h a t t h e shape and maxima of t h e bands s h i f t f o r t h e d i f f e r e n t c o a l s , f u g g e s t i n g a^ d i f f e r e n t u n d e r l y i n g c h a r a c t e r. band^ i s^ found i n t h e^ Beulah-Zap^ c o a l , with t h e i n t e n s i t y of t h i s band i n t h e o t h e r c o a l s d e c r e a s i n g in t h e same o r d e r as t h e oxygen c o n t e n t decreases. Deconvolution, second d e r i v a t i v e and c u r v e - f i t t e d s p e c t r a showed t h a t t h e composition of t h i s band v a r es. The Wyodak and Beulah-Zap c o a l s have major bands a t 1655 and 1562 c m - I , u s u a l l y a s s i g n e d t o conjugated c a r b o n y l s and c a r b o x y l a t e groups ( 2 ) , b u t o n l y weak f e a t u r e s near 1600 cm-' where t h e aromatic r i n g mode i s expected. Pocahontas and P i t t s b u r h c o a l s , however, have t h e i r s t r o n g e s t c o n t r i b u t t o n from a band a t 1611 cm-.

I n o r d e r t o measure t h e phenolic and a l c o h o l i c c o n t e n t of t h e c o a l s , a c e t y l a t e d d e r i v a t i v e s were prepared. The s u b t r a c t e d s p e c t r a of t h e a c e t y l a t e d and i n i t i a l c o a l s were c u r v e - f i t between 1800 and 1500 c m - l. Figure 4 shows t h e s u b t r a c t e d s p e c t r a f o r t h e I l l i n o i s , Pennsylvania, Wyodak and Pocahontas c o a l s. assigned to a c e t y l a t e d p h e n o l i c , a l k y l OH, and NH groups (2). Conversion f a c t o r s were obtained from node1 compounds. t h e amine r e s u l t s , only t h e phenolic and a l c o h o l i c r e s u l t s are r e p o r t e d. Table 3 g i v e s t h e r e l a t i v e abundance of p h e n o l i c and a l k y l OH groups i n t h e c o a l s. Contrary t o P a i n t e r ' s f i n d i n g s ( 2 ) , t h i s r a t i o is n o t very c o n s i s t e n t , b u t i n c r e a s e s s i g n i f i c a n t l y f o r t h e low rank c o a l s. However, t h i s d i s c r e p a n c y could b e due t o incomplete a c e t y l a t i o n of less^ a c c e s s i b l e^ OH^ groups.

ACKNOWLEDGMENT

The most i n t e n s e 1600 cm-

The

k

The bands a t 1770, 1740 and 1685 cm-' have been

Because of t h e f n c o n s i s t e n c y i n

The a u t h o r s thank D r. Karl Vorres of Argonne N a t i o n a l Laboratory f o r t h e c o a l samples.

REFERENCES

1. J. K. Brown, J. Chem. SOC., 744 (1955).
2. P. P a i n t e r , M. S t a r s i n i c and M. Coleman, i n "Fourier Transform I n f r a r e d Spectroscopy", Vol. 4, 3. R. F e r r a r o and L. J. B a s i l e , Eds., Academic P r e s s , Orlando (Fla.), Chap. 5, 1985.
3. S. H. Wang and P. R. G r i f f i t h s , F u e l 64, 229 (1985).

4. M. P. F u l l e r , I. M. Hamadeh, P. R. G r i f f i t h s and D. E. Lowenhaupt, Puel

• 61, 529 (1982).

5. N. R. S n y r l and E. L. F u l l e r , i n "Coal and Coal Products: A n a l y t i c a l C h a r a c t e r i z a t i o n Techniques", E. L. F u l l e r , Ed., ACS Symposium S e r i e s 205, American Chemical S o c i e t y , Washington, D.C., Chap. 5, 1982.
6. C. J. Chu, S. A. Cannon, R. H. Hauge and J. L. Margrave, Fuel 65, 1740 (1986).
7. P. R. Solomon, D. G. Hamblen, and R. M. Carangelo, i n Coal and Coal Products: A n a l y t i c a l C h a r a c t e r i z a t i o n Techniques", E. L. F u l l e r , Ed., ACS Symposium S e r i e s 205, American Chemical S o c i e t y , Washington, D.C., Chap. 4, 1982.

8. P. C. Painter, S. M. Rimer, R. W. Snyder and A. Davis, A p p l. Spec. 5. **271 (1981).

9. J. S. Gethner, Appl. Spec.** 2, **50 (1987).
10. R. Liotta, G. Brons and J. Isaacs, Fuel 62, 781 (1983). 11.** e. **C. Painter, M. Sobkowiak and J. Youtcheff, Fuel 66, 973 (1987).
11. N. Berkowitz,** "An Introduction to Coal Technology", Academic Press, New York, 1979.

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