- 153
/vr/sr
AUTO-OXIDATION POTENTIAL OF RAW AND RETORTED Oil SHALE
by
D. A. Green
Research. Triangle Institute
Post Office Box 12194
Research Triangle Park, North Carolina 27709
EPA Contract No. 68-02-3170-73
Project Officer
Edward R. Bates
Industrial Environmental Research Laboratory
Cincinnati, Ohio 4S26S
Industrial Environmental Research Laboratory
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
July 1984
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution
control methods be used. The Industrial Environmental Research Laboratory
— Cincinnati (IER1-CI) assists in developing and demonstrating new and
improved methodologies that will meet these needs both efficiently and
economically.
David G. Stephen, Director
Industrial Environmental Research Laboratory
Cincinnati
iii
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TABLE OF CONTENTS
Section
_ , iii
Foreword
iv
Abstract
vii
Figures
_ , . viii
Tables
1 Relating Characteristics of Solids to Storage Pile 1
1.0 Introduction -
1.1 Empirical Ranking
1.2 Analytical Model
1.3 Computer Simulation
1 4 Application of Solid-Gas Reaction Models
l!s Effects of Pore and Particle Size Upon Adsorption
1.6 Chemistry of Low-Temperature Oxidation
9
12
2 Description of Samples
3 Differential Scanning Calorimetry Testing and
Nonadiabatic Oxygen Absorption Testing i'
3.1 Differential Scanning Calorimetry 17
3.2 Nonadiabatic Oxygen Absorption Testing **
3.2.1 Introduction ~
3.2.2 Method: Phase I Samples *'
3.2.3 Apparatus: Phase I Samples •'
3.2.4 Method and Apparatus: Phase II Samples -JU
3.2.5 Results -°
3.2.6 Interpretation
4 Other Experimental Methods
4.1 Thermogravimetric Analysis |
4.1.1 Introduction ;?
4.1.2 Experimental |
4.1.3 Results ig
4.2 Peroxide Test ,g
4.3 Adiabatic Oxygen Absorption Test ^°
4 4 Pressure Differential Scanning Calorimetry ^
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FIGURES
Page
Spontaneous heating of dry, stage-crushed, 0- to
14-inch coal in an adiabatic calorimeter 2
2 Acceptable and unsatisfactory combinations of M and N
by van Doornum's model 6
3 Limiting cases of the grain model for solid-gas
reactions 10
4 Representation of general case of a grain model for a
storage pile where both reaction and diffusion
control the rate 11
5 DSC cell cross section 19
6 Effect of adding raw Utah (28 GPT) shale to Paraho
retorted shale (2° C/min heating ramp) 25
7 Effect of adding sulfur to raw/retorted shale mixture
(2° C/min heating ramp) 26
8 Nonadiabatic test apparatus 28
9 TGA Diagram 35
vii
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APPENDIX TABLES
Heat Capacity of C-a Raw Shale based on Initial Sample
Weight (-325 mesh) ' A-l
A-2 Heat Capacity of Lurgi Retorted Oil Shale Based on
Initial Weight (-325 mesh) A-2
A-3 Heat Capacity of Wyoming Smith-Roland Sub Bituminous
Coal Based on Initial Weight (-325 mesh) A-3
A-4 Heat Capacity of TOSCO II Retorted Shale Based on
Initial Sample Weight (-325 mesh) A-4
A-5 Heat Capacity of Paraho (-325 mesh) Retorted Shale •
Based on Initial Sample Weight A-5
A-6 Heat Capacity of Western Kentucky #9 Bituminous Coal
Based on Initial Sample Weight (-325 mesh) A-6
A-7 Heat Capacity of Pocahontas #3 Bituminous Coal Based
on Initial Sample Weight (-325 mesh) A-7
A-8 Heat Capacity of Union Retorted Shale/Raw Shale/Sulfur
Mixture at 17% Moisture Based on Initial Sample Weight
(-325 mesh) A-8
A-9 Heat Capacity of Hytort Retorted Shale Based on Initial
Sample Weight (-325 mesh) A-9
A-10 Heat Capacity of Utah Raw Shale (28 Gallon/Ton) Based
on Initial Sample Weight (-325 mesh) A-10
A-11 Heat Capacity of Utah Raw Shale (66 Gallon/Ton) Based
on Initial Sample Weight (-325 mesh) A-ll
ix
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APPE3TOIX FIGURES
Page
Thermogram of Lurgi retorted shale (-325 mesh),
heated at 2° C/minute in dry air A-12
B-2 Thermogram of TOSCO II retorted shale (-325 mesh),
heated at 2° C/minute in dry air A-13
B-3 Thermogram of Paraho retorted shale (-325 mesh),
heated at 2° C/minut in dry air A-14
B-4 Thermogram of Paraho retorted shale (-48 + 100 mesh),
heated at 2° C/minute in dry air A-15
B-5 Thermogram of C-a raw shale (-325 mesh), heated at
2° C/minute in dry air A'16
B-6 Thermogram of Wyoming Smith/Roland sub-bituminous coal
(-325 mesh), heated at 2° C/minute dry air A-17
B-7 Thermogram of Western Kentucky No. 9 Bituminous coal
(-325 mesh) heated at 2° C/minute in dry air A-18
B-8 Thermogram of Lurgi retorted shale (-325 mesh), heated
at 2° C/minute in humid air A-19
B-9 Thermogram of TOSCO II retorted shale (-325 mesh),
heated at 2° C/minute in humid air A-20
B-10 Thermogram of Paraho retorted shale (r325 mesh), heated
at 2° C/minute in humid air A"21
B-ll Thermogram of Paraho retorted shale (-48 + 100 mesh),
heated at 2° C/minute in humid air A-22
B-12 Thermogram of C-a raw shale (-325 mesh), hetaed at
2° C/minute in humid air A-23
B-13 Thermogram of Wyoming Smitn/roland sub bituminous coal- A-24
B-14 Thermogram of Western Kentucky No. 9 bituminous coal A-25
B-15 Thermogram of Utah (66 GPT) raw shale (first test) A-26
sd.
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APPENDIX FIGURES (continued) -
Page
Thermogravimetric test data, TOSCO II retorted shale,
(-325 mesh, 2° C/min heating ramp). Test 1 A-62
C-2 Thermogravimetric test data, TOSCO II retorted shale,
(-325 mesh, 2° C/min heating ramp). Test 2 A-63
G-3 Thermogravimetric test data, TOSCO II retorted shale,
(-325 mesh, 2° C/min heating ramp). Test 3 A-64
C-4 Thermogravimetric test data, Paraho retorted shale,
(-325 mesh, 2° C/min heating ramp). Test 1 A-65
C-5 Thermogravimetric test data, Paraho retorted shale,
(-325 mesh, 2° C/min heating ramp). Test 2 A-66
C-6 Thermogravimetric test data, Paraho retorted shale
(-325 mesh, 2° C/min heating ramp). Test 3 A-67
C-7 Thermogravimetric test data, Paraho retorted shale
(48 K 100 mesh, 2° C/min heating ramp). Test 1 A-68
C-8 Thermogravimetric test data, Paraho retorted shale
(-48 + 100 mesh, 2° C/min heating ramp). Test 2 A-69
C-9 Thermogravimetric test data, Paraho retorted shale
(-48 + 100 mesh, 2° C/min heating ramp). Test 3 A-70
C-10 Thermogravimetric test data, C-a raw shale (-325 mesh,
2° C/min heating ramp). Test 1 A-71
C-ll Thermogravimetric test data, C-a raw shale (-325 mesh,
2° C/min heating ramp). Test 2 A-72
C-12 Thermogravimetric test data, C-a raw shale (-325 mesh,
2° C/min heating ramp). Test 3 A-73
C-13 Thermogravimetric test data, Western Kentucky #9
bituminous coal (-325 mesh 2° C/min heating ramp).
Test 1 A-74
C-14 Thermogravimetric test data, Western Kentucky #9
bituminous coal (-325 mesh 2° C/min heating ramp).
Test 2 A-67
C-15 Thermogravimetric test data, Western Kentucky #9
bituminous coal (-325 mesh 2° C/min heating ramp)
Test 3 A-76
xiii
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APPENDIX FIGURES (continued)
Thermogravimetric test data, Union shale mixture
(-325 mesh, 2° C/min heating ramp). Test 2 A-93
C-33 Thermogravimetric test data, Union shale mixture
(-325 mesh, 2° C/min heating ramp). Test 3 A-94
C-34 Thermogravimetric test data, Utah raw shale (66 GPT)
(-325 mesh, 2° C/min heating ramp). Test 1 A-95
C-35 Thermogravimetric test data, Utah raw shale (66 GPT)
(-325 mesh, 2° C/min heating ramp). Test 2 A-96
C-36 Thermogravimetric test data, Utah raw shale (66 GPT)
(-325 mesh, 2° C/min heating ramp). Test 3 A-97
xv
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SECTION 1
RELATING CHARACTERISTICS OF SOLIDS TO STORAGE PILE BEHAVIOR
1.0 Introduction
The main challenge in determining reactivity of solids is to
measure, in the laboratory, properties of the solids which can be used
to predict how full-scale storage piles will behave. Factors that
influence the tendency of a storage pile to self-heat and eventually
ignite can be grouped into two main categories. The first category
includes those properties that are peculiar to the solid itself: reac-
tivity toward oxygen, and heat release as a function of temperature.
The second group of factors are those relating to the pile and its
construction: overall dimensions, particle size, degree of compaction,
homogeneity, ambient temperature, temperature of placed material, pre- .
cipitation, wind speed, etc. It is quickly seen that pile character-
istics are going to be more difficult to measure and most likely subject
to more variation than the properties of the solid itself.
Unfortunately, few workers have attempted to relate laboratory
determinations of reactivity of solids to storage pile behavior. The
problem of heat generation and transfer in a large storage pile is very
complex and requires several simplifying assumptions to obtain a solvable
problem. Perhaps the best attempts to compromise between simplicity and
reality have been made by the U.S. Bureau of Mines1 2 and in a paper by
van Dooraum.3
1.1 Empirical Ranking
In 1945, Elder et al.1 presented a comparison of the relative
tendency of 46 different coals to spontaneously heat. They used a
calorimeter with a capacity of 110 Ib to measure the temperature vs.
time of coals exposed to oxygen under adiabatic conditions. To eliminate
temperature gradients within the large solid sample, electrical heater:;
outside the container wall added heat as necessary to maintain the outer
wall temperature equal to that in the center of the sample. They used
coal samples predred nitrogen and maintained an upflow of pure oxygen
great enough so that the exit gas never dropped below 85 percent oxygen.
The calorimeter was preheated to a starting temperature in nitrogen
and allowed to equilibrate. Then oxygen was admitted and the temperature
was followed versus time. Figure 1 shows the nature of the curves
obtained. Test time varied from three hours to several days. By plot-
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the logarithm o£ the heating rate (°F/b.r) versus the reciprocal
temperature ("H"1), Arrheius relations were obtained for each coal's
reactivity. Each coal's reactivity at 212° F was then expressed relative
to a Pittsburgh seam bituminous coal which showed very low reactivity.
The results of Elder et al.1, cannot be directly related to pile
behavior, but are quite useful in that they provide an empirical ranking
of a coal's reactivity. The relative ranking of the 46 coals tested are
shown in Table 1.
Working with coal dust, Hertzberg et al.4 found that samples intro-
duced into an oven preheated to 150° C gradually increased in temperature
above that of the surroundings. The temperature continued to rise to an
"ignition temperature" characterized by an inflection point in the
temperature-time curve and then rose rapidly to a maximum. For Pittsburgh
(bituminous) coal the ignition temperature varied between 169° C for 2-7
micron particles and 344° C for 147-200 micron particles.
Merrill* using differential thermal analysis found that when coal
was diluted with inert firebrick material, both the preignition
"deflection temperature" (resulting from adsorption of oxygen on the
coal surface) and the ignition temperature increased. For a high vola-
tile bituminous coal, "deflection temperatures" increased from 207° to
277° C as coal concentration decreased from 100% to 8.1%. Ignition
temperature increased from 346° to 452° C as coal concentration decreased
from 51% to 8.1%.
Chamberlain et al.tt devised an apparatus in which coal was contacted
with heated humidified air while being heated at a constant rate. The
oxygen con- sumption and carbon dioxide production in this apparatus
were measured at three different temperatures by Schmeliag et al.7 and
used to calculate a spontaneous heating liability.
1.2 Analytical Model
Van Doornum3 devised a calorimeter particularly suitable for self-
heating studies. Usually both the rate of heat generation and thermal
conductivity of a solid are small. If a large sample is used in a
calorimeter, the heat produced may be easily determined, but a signifi-
cant temperature gradient will occur within the solid sample which is
unacceptable because it complicates the interpretation of experimental
results. If, on the other hand, a small sample is tested the temperature
gradient becomes negligible, but only very little heat is generated and
accurate measurements become difficult. Van Doornum overcame these
difficulties by using an aluminum block into which 19 holes of 1-inch
diameter were drilled. A subdivision of the sample into slender cylin-
ders separated by a material with a high thermal conductivity allowed
large samples to be used while maintaining essentially constant temper-
ature throughout the solid. Oxygen was admitted to the calorimeter
through a constant flow device, and the resulting heat generated versus
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time was measured. Test time varied from two to eight days, and runs at
different temperatures were made by varying the jacket temperature
surrounding the calorimeter.
Three coals of widely varying reactivities were measured;
Van Doornum found, as would be expected, that:
1. At a constant temperature and rate of oxygen supply, the rate
of heat generation decreases in a manner suggesting exponential
decay.
2. When oxygen is in excess, the reaction obeys Arrhenius1 equa-
tion for temperature dependence, q = A exp(-E/RT) where A and
E/R are constants and T is the absolute temperature. (Because
the
Arrhenius equation is difficult to work with mathematically,
van Doornum simplified it over the temperature range of in-
terest by replacing it with a more convenient equation:
q =A xp (aT*) where A and a are constants and T* is the
temperature rise of the coal relative to some arbitrary
reference temperature.)
3. When oxygen is not present in excess, the sample evolved heat
at a slower rate but the period of heat evolution lasted
longer. In other words, the oxygen concentration may limit
the rate of heat evolution, but the same total amount of heat
will eventually be released from the sample..
By using the measured reactivity properties of the solid, van
Doornum predicted the behavior of storage piles under several limiting
conditions. The case of most practical interest is that which considers
both the increased heat generation caused by rising temperatures and the
decreasing rate of heat generation caused by the decay in coal reactivity
with time. By assuming (1) that oxygen is present in excess throughout
the pile, (2) that the entire pile (or subarea within the pile area) is
at the same temperature, and (3) that the pile is of uniform construc-
tion, van Doornum could solve the resulting equations in terms of two
parameters. The first parameter, M, is the ratio of the increase in
heat generation due to temperature rise compared to the decrease in heat
generation resulting from reactivity decay. For values of M greater
than 1, the predicted temperature rises exponentially to infinity. When
li - I, the predicted temperature will rise linearly with time. Finally,
for values of M much less than 1, the maximum temperature remains finite.
A second parameter, N, accounts for the loss of heat from a storage
pile. The second parameter represents the relative magnitudes of the
decrease in heat generation from reactivity decay compared to the de-
crease in heat generation caused by losses from the exterior of the
piles. As N approaches infinity, pile conditions approach adiabatic.
For a given value of pile heat loss, there is a maximum reactivity value
for material can safely stored in this pile. For values of M higher
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In summary, van Doornum's approach has the advantages of mathemati-
cal, simplicity and requires only two experimental parameters. However,
it does not account for temperature variations within the storage pile,
but treats the entire pile as if it were of one temperature. Nor does
it account for the fact that oxygen may be depleted further into the
storage pile. This approach does not account for pile compaction which
reduces air influx and which has been shown to be the most effective
means of controlling spontaneous heating in the storage of reactive
lignite coals.8 9
1.3 Computer Simulation
To more fully account for the many factors at play in a storage
pile, Sondreal and Ellman2 carried out detailed computer simulations of
storage piles with various dimensions. They also conducted experimental
studies to determine values of the factors at work in spontaneous heat-
ing. Their work dealt exclusively with North Dakota lignite coals, but
is useful as a guide for other carbonaceous materials. A summary of
their results follows.
Reaction rates were determined by measuring the decrease in concen-
trations of oxygen in the void space of a tar filled with lignite. The
void space contained a relatively small quantity of oxygen in relation
to the weight of lignite. Consequently, the oxygen was nearly depleted
in periods lagging from a few minutes to a few hours depending on the
temperature level and the lignite reactivity. (In a separate set of
experiments the heat of reaction generated by the consumption of oxygen
was measured in a calorimeter similar to that used by van Doornum.)
Sample moisture content, particle size, or storage temperature
showed no' consistent effect on the heat of oxidation. Heat of oxidation
varied from approximately 75,000 calories per-gram mole adsorbed oxygen
at 20° C to almost 90,000 at 90° C. This heat liberation in low temper-
ature oxidation of lignite agrees generally with known values for similar
reactions. An upper limit of approximately 90,000 calories per gram
mole of adsorbed oxygen was used in all simulations to convert oxygen
consumption measured by the closed jar technique into a heat generation
rate. It should be noted that reaction rate measurements based on
oxygen consumption and the assumption of a constant heat of reaction may
not be valid for substances other than the lignite studied.
The influence of sulfur (particularly pyrite) on the oxidation of
56 lignite samples was investigated. After statistical analysis of the
resulting data, Sondreal and Ellman2 found, as did Bacharach et al.1O
that for rate prediction, correlation with sulfur content is of no
value.
Sondreal and Ellman2 used the above and several other experimentally
determined values in a computer program to predict temperature distribu-
tion in lignite piles. They assumed that heat is transferred within the
pile by conduction only and that the boundary temperature of the pile is
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oxygen can permeate a pile much more rapidly than it is con-
sumed, its concentration becomes uniform throughout the pile. Each
particle then reacts and generates heat at the same rate regardless of
its position in the pile. This limiting case is called chemical-reaction
controlled. If, on the other hand, the infiltrating oxygen reacts as
quickly as it can reach unconsumed coal, the reaction will be confined
to a narrow zone which will proceed inward as more and more of the pile
reacts. This situation is termed diffusion controlled. Figure 3 pre-
sents the two limiting cases schematically.
For a pile with constant temperature, the intermediate case that is
illustrated in Figure 4 can easily be treated12 by introducing a single
parameter, a, representing the relative rates of chemical reaction and
gas diffusion into the pile.^ In chemical reaction studies, this param-
eter, is called the Thiele modulus and represents what may be the best
means of quantifying air infiltration into compacted storage piles.
Further work is needed to consider models for porous solids that
include nonisothermal effects13-18 and to experimentally determine the
effective rate of oxygen diffusion in large piles of varying compaction.
Such work is outside the scope of this study which has the more limited
goal of comparing the reactivities of various carbonaceous solids, not
detailed modeling of pile behavior. It does appear, however, that once
solid reactivities Cat ambient oxygen levels and known solid surface
areas) have been determined, models exist which can be adapted with
little effort to predict the effect of storage pile construction.
1.5 Effects of Pore Size and Particle Size Upon Adsorption
In research with coal of various ranks, the size and volume of
pores has been found to affect the mechanisms of oxidation. In experi-
ments conducted at 200°-250° C, Avison et al.17 found two distinct types
of oxidation behavior depending on the pore distribution of the coals.
Large-pore coals (0.040-0.062 csa2/g > 300 A) showed a long period during
which oxidation was limited by oxygen availability. When most of the
available oxidation sites were used up diffusional resistance became
important and rates fell. In contrast, small-pore coals (0.009-0.022
Q
cm3/g > 300 A) showed oxidation rates which declined monotonically from
the very beginning of the test. Kam et al.18, suggested that low tem-
perature oxidation of bituminous coal takes place solely on external
surfaces and macropores. Citing extremely slow oxygen permeation into
the raicropores, they neglect diffusion into and out of the interior of
the coal particle as insignificant.
Several researchers have confirmed the importance of external
surface adsorption through studies of the effect of particle size.
Working with highly volatile bituminous coal at 135° C, Mahajan et al.ia
found that 40 x 70*mesh particles took 15 times as long as 200 x 250
mesh particles to absorb the same amount of oxygen. For small-pore, low
and medium volatility bituminous coal, Avison et al.17 found oxidation
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FIGURE 4. Representation of general case of a grain model
for a storage pile where both reaction and
diffusion control the rate. (Source: Research
Triangle Institute)
11
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SECTION 2
DESCRIPTION OF SAMPLES
Samples of raw shale, retorted shale and coal were tested in this
study. Testing was conducted in two phases; sample handling procedures
for the samples obtained in the first and second phase differed slightly.-
In the first phase of the study, retorted shale samples from the
Lurgi, TOSCO II, and Paraho direct-mode processes were tested in addition
to a raw shale sample from Federal lease tract C-a in Colorado, a Wyoming
Smith-Roland subbituminous coal, and a Western Kentucky #9 bituminous
coal. Samples of raw shale and retorted shale were obtained from Rio
Blanco Oil Shale Company (raw C-a shale from R-5 zone, elevation 6141 ft
mucked from blast #3 on May 30, 1980), TOSCO, Incorporated (TOSCO II
retorted shale, Colony Mine), Development Engineering (Paraho retorted
shale, Anvil Points Mine), and Cathedral Bluffs Oil Shale Company (Lurgi
retorted shale, C-b tract shale). Coal samples were obtained from the
AMAX Coal Company and the Kentucky Center for Energy Research Laboratory.
All samples were reduced in size, riffled, ground to final size, and
riffled again to select a small subsample for testing. The coal samples
were ground and sized under nitrogen.
In the second phase of the study, a mixture of retorted shale, raw
shale, and byproduct sulfur from the Union B process was tested in addi-
tion to Hytort retorted shale, (Kentucky origin) two raw shale samples
of different grades from Federal lease tract Ua/Ub in Utah and Pocahontas
#3 bituminous coal. The Union sample was prepared at RTI from separate
samples of retorted shale, raw shale fines and byproduct sulfur provided
by Union Oil Science and Technology Division. These material's were
ground and sized separately and then mixed in the proportion of 5.47
weight-percent raw shale fines to 0.14 weight percent sulfur, with the
balance retorted shale. All of these materials had negligible moisture
after grinding. The resulting mixture was homogenized and brought to 17
weight percent moisture with distilled, deionized water. The Union oil
shale mixture was prepared in this manner per instructions from Union
Oil, in order to simulate Union's plans for disposal at their Long Ridge
Plant in Colorado.
The Hytort shale was obtained from Phillips Petroleum. The Utah
shale was obtained from the U.S. Department of Interior, Bureau of Land
Management. Four sections of core were sent from core hole X-13; indi-
vidual assays were provided for each section. The two leaner samples
were composited to make a 28 gallon per ton sample. The two richer
13
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TABLE 2. TOTAL SULFUR CONTENT OF SAMPLES (WEIGHT %)
Western Kentucky #9 Bituminous Coal
(-325 mesh)
Hytort Retorted Shale (-325 mesh)
Utah Raw Shale (66 GPT) (-325 mesh)
C-a Raw Shale (-325 mesh)
Lurgi Retorted Shale (-325 mesh)
Utah Raw Shale (28 GPT) (-325 mesh)
Union Shale Mixture* (-325 mesh)
Pocahontas #3 Bituminous Coal (-325 mesh)
Wyoming Sub-Bituminous Coal (-325 mesh)
TOSCO II Retorted Shale (-325 mesh)
Paraho Retorted Shale (-325 mesh)
Paraho Retorted Shale (-48 + 100 mesh)
As received
3.65
2.39
1.84
0.97
0.86
0.75
0.68
0.64
0.60
0.58
0.57
0.57
Dry
3.73
2.40
1.85
0.98
0.86
0.75
0.68
0.65
0.63
0.58
0.57
0.57
brought to 17% moisture, sulfur content would be 0.56%.
TABLE 3. HIGHER HEATING VALUES OF SAMPLES (-325 mesh)
W. Kentucky #9 Bituminous Coal
Pocahontas #3 Bituminous Coal
Wyoming Sub-Bituminous Coal
Utah Raw Shale (66 GPT)
Utah Raw Shale (28 GPT)
C-a Raw Shale
TOSCO II Retorted Shale
Hytort Retorted Shale
Paraho Retorted Shale
(-48 -i- 100 mesh)
Union Shale Mixture*
Paraho Retorted Shale
Lurgi Retorted Shale
J/g
28210
27870
20600
14400
4840
2030
1000
972
686
483
434
100
(BTU/LB)
(12130)
(11980)
(8860)
(6200)
(2080)
(871)
(430)
(418)
(295)
(208)
(187)
(44)
J/g
30350
28190
26890
14500
4860
2040
1010
977
688
486
437
100
(BTU/LB)
(13050)
(12120)
, (11560)
(6240)
(2090)
(878)
(433)
(420)
(296)
(209)
(188)
(44)
If brought to 17% moisture, the
heating value would be 173 Btu/lb.
15
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SECTION 3
DIFFERENTIAL SCANNING CALORIMETRY TESTING AND
NONADIABATIC OXYGEN ABSORPTION TESTING
3.1 Differential Scanning Calorimetry
Differential scanning caloriraetry (DSC) involves the measurement of
heat evolved or absorbed by a sample at a given temperature relative to a
known reference material at the sane temperature. When the temperature is
increased or decreased, heat effects arise from differences in specific
heats, phase changes and chemical reactions. Low temperature oxidation is
an exothermic reaction. When spontaneous heating occurs, the heat produced
by this reaction (and other exothermic reactions including the heat of
wetting) is greater than the heat that is rejected to the surroundings, and
the temperature of the material which is oxidizing increases. As the temper-
ature of the material increases, the rate of oxidation increases and, in
some cases, an even more rapid temperature increase then occurs.
• DSC data, obtained while the temperature of the sample and reference
are increased at a slow constant rate, indicate the difference in heat flow
between sample and reference as a function of temperature. When the refer-
ence is an empty sample pan of equal mass and specific heat to the pan in
which the sample is held, the net heat effect is that produced by the sample.
When the temperature of the apparatus is controlled to eliminate the possi-
bility of phase changes in the sample, endothennic effects are associated
with the heat capacity of the sample, and with some materials, such effects
as drying, desorption of gases, and volatilization. Exothermic effects in
excess of the sample heat capacity are associated with exothermic chemical
reactions.
Several previously described approaches4'5 characterized the self-
heating tendency of materials by promoting low temperature oxidation by
heating samples in the presence of air or oxygen and noting the point at
which the sample temperature began to rise above that of its surroundings.
This approach has been followed in this study using DSC to detect the onset
temperature of this exothermic reaction and the extent of heat released when
samples were slowly heated in the presence of air.
All samples were tested at a particle size of -325 U.S. mesh. The
Paraho retorted shale sample was also tested at -48 + 100 U.S. mesh. The
set of samples obtained in the first phase was tested in both dry and humid
air (0.016 g H20 per liter dry air). As only minor differences in response
were observed due to humidity, the samples obtained in the second phase were
17
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U.VMM
SAS
ssc eiu. caess-sicno*
FIGURE 5. DSC cell cross section.
(Source: duPont Instruments)
by permission
19
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TABLE 6. EXOTHERMIC ONSET TEMPERATURE OBSERVED IN OXIDATION OF COAL,
OIL SHALE, AND RETORTED OIL SHALE
(2° C/MINUTE HEATING RAMP, -325 mesh, except where acted)
MATERIAL
Wyoming Subbiturainous Coal
Wyoming Subbituminous Coal
Western Kentucky #9 Bituminous Coal
Western Kentucky #9 Bituminous Coal
Utah Raw Shale (66 GPT)
C-a Raw Shale
C-a Raw Shale
Utah Raw Shale (28 GPT)
Pocahontas #3 Bituminous Coal
TOSCO II Retorted Shale
Paraho Retorted Shale
Paraho Retorted Shale
Paraho Retorted Shale (-48 •*• 100)
Paraho Retorted Shale (-48 +• 100)
TOSCO II Retorted Shale
Union Shale Mixture
Hytort Retorted Shale
Lurgi Retorted Shale
Lurgi Retorted Shale
*No exotherm observed up to 550° C.
ATMOSPHERE
Humid Air
Dry air
Humid air
Dry air
Dry air
Humid air
• Dry air
Dry air
Dry air
Humid air
Dry air
Humid air
Humid air
Dry air
Dry air
Dry air
Dry air
Dry air
Humid air
TEMPERATURE
190 ° C
190
190
193
211
225
226
227
230
296
300
300
300
302
306
331
357
->-,
*
21
-------
The effect of humidity on exothermic onset temperature was most notice-
able for the TOSCO II retorted shale in which a 10° C reduction was observed
for the test conducted with humid air. A slight decrease in exothermic
onset temperature was observed for the bituminous coal. Reports o'f adiabatic >
experiments by Guney23 have demonstrated an extremely significant effect of
humidity on low temperature (<1QO° C) spontaneous heating of coal. Much less
dramatic effects were noted upon the measured exothermic onset temperature
in this study because the parameter measured for ranking purposes was con-
sistently above the normal boiling point of water. The reason why humidity
did not produce a more significant effect in this study may lie in the rapid
"forcing" of the reaction (2° C/min heating ramp) in the nonadiabatic DSC
testing. Additionally, the equilibrium moisture content of the shale and
shale refuse at the test conditions is unknown. The role of the heat of
wetting of coal in raising its temperature is well known; at higher temper-
atures the rate of atmospheric oxidation is accelerated and temperature
increases to the point of spontaneous ignition may result. In all cases
except for the Western Kentucky bituminous coal, the tests conducted humi-
dified air produced slightly greater exothenns. The ranking of the sample
was however, unaffected by the difference in atmosphere.
Varying particle size had a negligible effect upon the exothermic onset
temperature of Paraho retorted shale. It is uncertain whether this is
because intraparticle diffusion effects are unimportant in the reaction or
because the heating ramp obscures differences in heat release once the
reaction has been initiated.
Based on exothermic onset temperatures, none of the raw shale samples ;
are as susceptible to spontaneous combustion as the Wyoming subbituminous
and Western Kentucky (high volatility) bituminous coals. The western shales ,
are more susceptible to spontaneous combustion than the Pocahontas #3 low
volatility bituminous coal which is considered to present a low hazard
relative to most other coals. None of the retorted shale samples exhibited
exothermic onset temperatures lower than the Pocahontas ?£3 coal, and these
are therefore even less likely to spontaneously combust.
An additional series of tests was conducted to determine the effect of
codisposal of raw shale fines and elemental sulfur with retorted oil shale.
In some cases, retorting processes are designed to accept material of a
certain minimum size. In grinding and preparation of the raw shale, fines
(i.e., particles below the minimum size) are produced. As raw shale has
been found to pose a greater hazard of spontaneous combustion than retorted
shale, the effects of adding up to 20% raw shale to retorted shale was
investigated. A similar situation exists with respect to sulfur removed
from retort effluents. In some cases this sulfur may be disposed of together
with retorted shale and/or raw shale fines. A series of tests was conducted
to determine the effect of codisposal of elemental sulfur on spontaneous
combustion potential of retorted shale.
In order to investigate the effects that adding raw shale fines might
have on retorted oil shale self heating properties, raw shale was mixed with
Paraho retorted shale (note that the Paraho project proposes separate dis-
posal as opposed to mixing of these wastes). Thermograms for three tests
23
-------
t-l
a
o
u
-------
retorted shale from the Paraho, TOSCO, and Lurgi processes. This work was
supervised by Mr. Charles Hafaernicht of the DRI Chemical Division. The
samples obtained during the second phase of the study were tested at Research
Triangle Institute (RTI) via an equivalent procedure using a dif-ferent
apparatus and instrumentation setup. One sample from the first sample group
was also tested at RTI to confirm the comparability (±4%) of the two appara-
tus.
3.2.2 Method: Phase I Samples
The test apparatus and procedure were based on those of Schmeling et
al.7. This procedure was modified to reduce operator time and improve
precision. A mass flow controller was used instead of needle valves for
inlet gas control 'and a temperature controlled oven was used instead of an
oil bath to maintain apparatus temperature. Chromatographic data acquisi-
tion and reduction was done electronically rather than by use of strip chart
recorders.
The standard testing sequence consisted of placing 100 g of -48 + 100
mesh (150 to 300 pm) sample into a glass sample cell (see Figure 8) where it
was equilibrated at ambient temperature with humidified (ambient temperature
saturation) air flowing through the sample at 60 raL/min. This required
about two hours if the sample had been stored under nitrogen. When the
inlet and outlet oxygen concentrations equalized, the oven was closed and
the run started. The sample temperature was elevated at a rate of 25° C/hr
up to a final temperature of 300° C. The effluent gas stream was analyzed
every 12 minutes for oxygen, carbon monoxide, carbon dioxide, and methane.
After reaching 300 ° C, the oven was shut off and allowed to cool. Occasion-
ally, a sample continued to oxidize in the cell and was extinguished by
purging with nitrogen.
For this program, two size ranges of each of six available sample
materials were analyzed. The -43 + 100 size (ISO to 300 |Jm) is the specified
size range (Schmeling, et al.r) for this test and all samples tested with
the exception of the Lurgi retorted shale were tested in this size range.
In addition, -325 mesh (< 45pm) cuts from each sample were tested in an
attempt to simulate processing fines such as those collected from baghouses,
etc. The Lurgi material was tested in the -200 + 325 (45 to 75 pm and -325
(45 |Jm) size ranges (no appreciable Lurgi material existed in the original
sample in larger size ranges). Triplicate determinations were made for each -
sample type and size range.
3.2.3 Apparatus: Phase I Samples
The gas introduction system consists of a nitrogen and air supply, a
humidifier and a flow measurement and control assembly. The gas supplies
consist of bottled dry nitrogen and manufactured air containing 21 percent
oxygen and 79 percent nitrogen by volume. Standard two-stage pressure
regulators reduce tank pressures to 2.0 atm (30 psi). A manually operated
switching valve allows the operator to select either the nitrogen or air
stream. A temperature controlled bubbler-type humidifier controls the water
27
-------
content of the gas stream. Finally, a mass flow controller maintains a
steady flow of 60 mL/min (air adjusted) to the cell.
A temperature-controlled oven is used to adjust the sample -temperature.
Thermocouples inside and outside of the sample cell have verified that all
sample types will track the oven temperature to within ±3° C throughout the
temperature range. A blower located within the oven assures uniform temper-
atures throughout. Oven temperature is controlled by a West Model 270-A
temperature programmer which ramps the temperature in response to a clock-
driven cam. The cam is cut to adjust the temperature from 25° C to 300° C
at a rate of 25° C/hr. A preheater heats the incoming gas stream to oven
temperature prior to its entry to the test cell. The preheater has the
capacity to handle a 400 mL/min gas stream to a 300° C oven temperatures at
its exit. This insures that at only 60 mL/min, a thermally equilibrated gas
stream enters the cell.
The all-glass cell has a 40 mm inside diameter and a 150 mm nominal
height and is fitted with a bottom gas entry through a glass frit and &
wide-mouthed spherical glass joint top for sample loading. Three glass
sidearms have been added for thermocouple probes at 40, 80, and 120 mm from
the cell bottom. These allow separate temperature measurements of incoming,
central, and exiting gas/sample regions to be made.
The gas stream exits the sample cell through a glass frit for filtering
and immediately upon exiting passes through a condenser and liquid trap.
This trap is cooled by an ice bath and removes all condensable water and
higher molecular weight hydrocarbons from the gas stream.
The principal method of gas analysis is a dedicated gas chromatographic
system consisting of three automated switching valves, two columns, and a
thermal conductivity bridge detector. In series with this system, continu-
ous real-time carbon monoxide and oxygen detectors are used to supplement
the analyses.
An automated stream selector valve can be switched between the sample
line, a zero gas nitrogen supply or a calibration standard gas. The gas
stream is sampled by a 0.5 mL loop sampling valve. At regular predetermined
intervals the sampling loop is rotated to the "inject" position where a
helium carrier gas loads the sample into a 1.6 mm x 50 cm packed Chromesorb
102 column which is used only to separate carbon dioxide from the effluent
gas stream. All other gases are allowed to pass through the first column
and are collected on a molecular sieve column for temporary storage and
separation. Just prior to the time when the carbon dioxide is eluted from
the Chromosorb column, a series-bypass valve switched to allow the gas to be
bypassed to the thermal conductivity detector, where it is quantitatively
measured. After the carbon dioxide peak has passed the detector, the series-
bypass valve again switches to allow the remainder of the gases stored on
the molecular sieve to be separated and quantitatively detected. The molecu-
lar sieve column is a 1.6 mm by 120 mm column packed with molecular sieve 5A
and has the ability to separate hydrogen, oxygen, nitrogen, carbon monoxide
and hydrocarbons (methane in this program) from the sample stream, but
irreversibly absorbs carbon dioxide.
29
-------
X2 = carbon dioxide concentration at 175° C - carbon
dioxide concentration at 150° C
All concentrations are expressed in volume percent.
Although carbon monoxide concentration is not explicitly included in
the above formula, the reaction of oxygen to form carbon monoxide increase
the parameters hi, ha, and hs which contributes to an increased S index.
The total measured carbon dioxide concentration does not necessarily result
from oxidation only but may also result from pyrolysis and desorption reac-
tions. The potential contribution of these mechanisms is extremely low at
the conditions employed in the nonadiabatic tests. Cummins and Robinson23
found that after 90 days in an inert helium atmosphere at 150° C only 20% of
the kerogen in Green River shale was converted, and, this material was
converted mostly to bitumen and oil "as evidenced by little or no formation
of gas " At 200° C, the corresponding conversion was 3.0%. Arnold24
found that mineral decomposition, i.e., the calcining of calcium carbonate
and magnesium carbonate was negligibly slow up to about 600° C. For these
reasons, no attempt was made to correct the gas analyses for the effects of
pyrolysis (i.e., for COg which might have evolved even in the absence of
oxygen).
Using data averaged from triplicate tests, S indices were determined
for the materials tested. The samples are ranked in order of decreasing
spontaneous combustion hazard in Table 8. The parameters used in calcula-
tion of the S index are also given. Gas concentration data from which these
parameters have been obtained are given in Appendix B. Tables B-l through
B-9 give mean gas compositions at specific temperatures for each sample
type. Tables B-10 through B-16 given mean concentrations of oxygen, carbon
monoxide, and carbon dioxide as a function of temperature.
Samples tested in the first phase of the study were tested in two
different particle sizes. The difference in particle size produced a con-
siderable but inconsistent difference in S index. The C-a raw shale and
TOSCO retorted shale produced higher S indices when tested in the larger
particle size. The remaining samples produced higher S indices when tested
in the finer particle size. The difference in results due to particle size
did not affect relative rankings of samples tested in the first phase of the
study. In the second phase, samples were tested at -325 mesh only.
Decreasing solid particle sizes would be expected to increase the rate
of gas/solid reactions (due to increased surface area) and thus increase the
S index. The C-a raw shale and Tosco retorted shale did not exhibit this
behavior. One explanation for this observation would be channeling of the
gas flow through clumps of finely divided material in the sample cell. This
would decrease gas/solid contact and effectively decrease the surface area
of the smaller particles.
31
-------
TABLE 8. SPONTANEOUS COMBUSTION INDEX AND CALCULATION PARAMETERS
OF MATERIALS SUBJECTED TO SONADIABATIC TEST (Tested dry)
MATERIAL
(-325 nesh unless stated)
S
Wyoming Subbituminous Coal4 165.75
Wyoming Subbituminous Coal* 108.00
(-48 * 100 mesh)
Raw Utah Shale (66 OPT)
Western Kentucky />9
Bituminous Coal*
Raw Utah Shal? (23 OPT)
Pocahontas #3 Bituminous
Coal
Western Kentucky ,'M
Bituminous Coal*
(-43 * 100 mesh)
Raw Shale
C-a (-48 * 100 aesh)
Raw shale
C-a
Union Shale Mixture
Hytort Retorted Shale
TOSCO II Retorted Shale*
(-48 * 100 mesh)
TOSCO II Retorted Shale*
Paraho Retorted Shale*
Paraho Retorted Shale*
(-43 ••• 100 nesh)
Lurgi Retorted Shale*
Lurgi Retorted Shale*
(-200 * 325 mesh)
where S * the
ht » 21 -
ha * 21 -
hs * 21 -
Xi 3 carb
36
60.00
44
42
37.50-
6.39
5.59
4.6
3.3
3.60
1.38
0.27
0.21
0.00
0.00
spontaneous
* »3 xt x,
9.
44
3.55
7.41
2.
1.
3.
4.
0.
I.
0.
0.
1.
0.
0.
0.
0.
0.
97
55
43
35
65
12
41
90
10
57
10
63
38
32
17.
' 17.
19.
12.
3.
11.
12.
2.
2.
3.
3.
1.
I.
0.
0.
C-)o.
0.
42
60
7
59
49
2
34
60
50
00
14
44
23
47
34
04
14
20.97
20.
20.
38
3
20.87
18.
21.
20.
6.
6.
6.
5.
2.
2.
0.
1.
0.
0.
2
0
35
55
09
37
26
79
02
78
04
00
15
4.
,48
2.30
3.
1.
1.
1.
1.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
56
16
10,
03
13
23
17
61
43
22
03
01
02
00
00
5.48
4.
10
1.36
3.
2.
2.
05
38
13
1.70
1.
1.
0.
0.
1.
0.
0.
0.
0.
0.
43
23
76
68
57
79
42
21
00
01
combustion index
oxygen concentration
oxygen concentration
oxygen concentration
on dioxide concentrat.
at 125°
at 150°
at 175°
ion at 1!
C
c
c
>o° c
carbon dioxide concentration at 125° C
carbon dioxide concentration at 173° C
carbon dioxide concentration at 150° C
^Source: Denver Research Institute
33
-------
AIR INLET
FURNACE.
QUARTZ TUBS. JL __
\ L«OO~CO~!
SAMPLE PAN
THERMOCOUPLE
BALAWCS HOUSING
FIGURE 9. TGA Diagram
35
-------
TABLE 9. WEIGHT LOSSES OBSERVED AT 300° C AND 500° C
DURING THERMOGRAVIMETRIC ANALYSIS
(2°/MIM HEATING RAMP, DRY AIR, -325 mesh)
MATERIAL Weight3oo/Weight12o Weightsoo/Weig;ht12o
Wyoming Subbiturainous Coal
Pocahontas #3 Bituminous Coal
.Utah Raw Shale (66 GFT)
Western Kentucky #9 Bituminous Coal
Utah Raw Shale (28 GPT)
C-a Raw Shale
TOSCO II Retorted Shale
Union Shale Mixture
0.25
' 0.52
0.86
0.94
0.94
0.95
~ 1.0
" 1.0
0.07
0.23
0.62
0.09
0.86
0.92
0.95
0.95
The above methods of ranking have the advantage of being numerically
unambiguous. They do not reveal much information about the nature of the
weight loss or the potential for a self-sustaining reaction to occur. A
procedure was employed involving an attempt to determine the temperature at
which the weight loss increases rapidly. All of the materials with the
exception of the Lurgi retorted shale showed a gradual weight loss on heating
which began to accelerate at a particular point. An attempt was made to
characterize the point at which the rate of weight loss began to increase by
extrapolating the portions of the weight temperature curves representing the
first two linear weight loss periods to an intersection. This method did
not yield a valid indicator temperature, however, as it did not rank the
three coals in the known order of auto oxidation potential.
Another procedure was attempted involving ranking of materials on the
basis of the temperature at which the maximum rate of weight loss occurred.
This approach did not appear" to be suitable because the temperature at which
the maximum weight loss occurred for the Western Kentucky coal was greater
than that for three of the retorted oil shale samples. A third unsuccessful
approach involved ranking by the temperature at which the sample temperature
outran the heating ramp (due to combustion). This method proved unsuitable
because this phenomenon was only observed with the three coals. In addition,
for these materials, the order was inconsistent with expected behavior, as
the Pocahontas #3 coal ignited and outran the temperature program at 295° C,
well ahead of the Western Kentucky coal which ignited at 385°'C. It wasi
concluded therefore that thermogravimetric analysis is not very useful in
determining auto oxidation potential. Data plots for the TGA tests are
given in Appendix C.
37
-------
in the center of the reaction cell, may not have accurately measured the
maximum temperature in the cell. Thus, the incoming air could be at a lower
temperature than any particular "hot spot" and could possibly quench the
reaction.
4.4 Pressure Differential Scanning Calorimetry
An attempt was made to develop an isothermal DSC test in which a sample
is held at a constant temperature in an oxygen atmosphere until a spontaneous
temperature rise is observed. Similar tests are used to characterize the
degradation of polymers.28 To reduce the test time, a high pressure of
oxygen was used. The apparatus was identical to that described in Section 3
except that a high pressure DSC cell was used. In successive 16-hour tests,
oxygen pressure was increased from 35 to- 69 atmospheres at temperatures up
to 150 ° C. Even at the most severe conditions of 69 atmospheres oxygen
pressure and 150° C, no exotherm was observed within 16 hours. Wyoming
subbituminous coals, C-a raw shale, and Paraho retorted shale were tested in
this manner.
39
-------
All tests were run in triplicate. Tests conducted at DRI on replicate
samples yielded S (Schemling7) indices within 5% of the mean. Tests con-
ducted at RTI on coal and raw shale samples yielded S indices within 5% of
the mean; tests conducted at RTI on retorted shale samples yielded S indices
within 20% of the mean.
Samples obtained in the first phase of the study were ground and split :
at DRI with a portion forwarded for testing at RTI. To evaluate representa-
tiveness of splits, subsplits from each portion were analyzed for total
sulfur. Comparative data are given in Table 10.
To confirm comparability of data from the nonadiabatic oxygen absorp-
tion apparatus at RTI and DRI, one sample was tested in both apparatus. C-a.
raw.shale produced an S index of 5.59 at DRI and 5.1 at RTI. '
5.3 Specific Heat Determination
Specific heat determinations were based on sample heat flows relative
to heat flows observed with a standard reference disk of sapphire. DSC
tests were conducted under identical conditions of temperature ramp and gas
flow rate for sample and standard. An empty sample pan was used as a refer-
ence for both the sapphire standard tests and the sample tests. Any effects:
due to changing cell calibration or baseline would be.identical in the two
tests and exert no influence on the result. The tests were conducted in
triplicate. Heat flows varied among tests of the same material due to
slightly different sample masses but calculated specific heats were consis-
tently within 0.1 J/g for replicates. The values that were reported are
given in two significant figures as integration was carried out at 20° C
intervals and precise average values over these intervals were difficult to
obtain from the complex thermograms.
5.4 Heating Value, Sulfur, and Organic Carbon Determination
Determinations of higher heating value29, sulfur30 and organic carbon
were done in duplicate. Organic carbon was determined by removing carbonate
from the samples with boiling HC1, followed by analysis for carbon.31
Reported values are based on original sample weight. Heating value deter-
minations were ±15% of the mean for the retorted shales (which is to be
expected as these have very low values) and ±4% for the coal and raw shale
samples. Duplicate total sulfur analyses varied by a maximum of 0.05% from
each other. Duplicate organic carbon analyses varied by a maximum of 7% ;
from the mean.
41
-------
SECTION 6
CONCLUSIONS
It must be noted that the results reported here are based on a very
limited number of samples of raw and retorted shale. Substantial variations
in composition of raw shales occur with, geographic and stratigrapfaic
location. The retorted shale samples came from pilot plant operations
which, may not be completely representative of commercial operations. Hence,
it is strongly recommended that actual samples of waste materials proposed
for field disposal be tested to determine their actual spontaneous combus-
tion hazard.
Retorted shales that were investigated in this study are unlikely to
present a spontaneous combustion hazard. These include retorted shales from
the Paraho direct, TOSCO II, Hytort, and Lurgi processes and a mixture of
retorted shale, raw shale "fines," and sulfur from the Union B process.
These materials proved to be far less reactive than Pocahontas #3 low-
volatility bituminous coal which is generally regarded at the low end of the
spectrum of coals susceptible to spontaneous heating. This conclusion was
reached on the basis of both the exothermic onset temperature, as determined
by differential scanning calorimetry, and the nonadiabatic oxygen absorption
test, and supported by TGA weight loss data. The Lurgi retorted shale is
non-combustible and could not burn even if an attempt was made to ignite it.
The raw western shales, while not as liable to ignite as the Wyoming
Smith-Roland subbituminous coal (which is generally placed at the higher end
of the spectrum of coals susceptible to spontaneous heating) present a
potential hazard. The richer of the Utah shale samples (66 GPT) is particu-
larly reactive, falling between the Wyoming subbituminous and the Western
Kentucky high volatile bituminous coal (of intermediate reactivity with
regard to coal) in the nonadiabatic oxygen absorption test. In the DSC
test, it falls below the Western Kentucky coal but above the relatively
unreactive Pocahontas #3 coal. In the TGA weight loss test (based on mass
remaining after heating to 300° C), a greater weight loss is observed with
this sample than with the Western Kentucky bituminous coal.
The leaner Utah shale (28 GPT) is intermediate in tendency to auto-
ignite between the Western Kentucky coal and the Pocahontas #3 coal in both
the nonadiabatic oxygen absorption test and the DSC test (ranked by exo-
thermic onset temperature). This material falls below the coal samples in
the TGA weight loss tests. By Schmeling's criteria (S index > 30), this is
also a potential hazard. The C-a shale has about the same exothermic onset
temperature as the leaner Utah shale (i.e., intermediate between the Western
Kentucky and Pocahontas bituminous coals, but considerably ranks lower than
43
-------
results conformed to generally observed rankings of spontaneous combustion
potential. Of the other tests considered, the peroxide test was technically
unsound; pressure differential scanning calorimetry and adiabatic oxygen
absorption tests did not produce useful, reproducible results in'the course
of this particular study. These methods may, however, after further develop-
ment, be made useful. The therraogravimetric analysis weight loss test,
while potentially useful in characterizing samples, was found unsuitable as
results for coal samples did not conform to generally accepted spontaneous
combustion rankings, and the retorted shale samples produced an insufficient
response to evaluate.
A summary of results obtained in the differential scanning calorimetry
and nonadiabatic oxygen absorption testing is given in Table 11. As no
reference standards are available for the test parameters which were deter-
mined, the accuracy of these tests cannot be determined. However, the
ranking of the materials can be used as an indicator of relative spontaneous
combustion hazard.
TABLE 11. SUMMARY OF RESULTS FROM DIFFERENTIAL SCANNING CALORIMETRY
AND NONADIABATIC OXYGEN ABSORPTION TESTING
Material
Wyoming Subbiturainous Coal
Western Kentucky #9 Bituminous Coal
Utah Raw Shale (66 GPT)
C-a Raw Shale
Utah Raw Shale (28 GPT)
Pocahontas #3 Bituminous Coal
Paraho Retorted Shale
TOSCO II Retorted Shale
Union Shale Mixture
Hytort Retorted Shale
Lurgi Retorted Shale
DSC* Nonadiabatic
onset exo therm test
°C J/g S index
190
193
211
226
227
230
300
306
331
357
***
10,900
13,800
8,320
920
2,990
15,700
480
560
860
1,340
"0
165
60
86
5.6
44
42
0.27
1.4
4.6
3.8
0.00
*
tested in dry air, particle size: -325 mesh
no exotherm observed to 550° C
45
-------
13. Wen, C.Y., and S.C. Wang, Industrial Engineering Chemistry, 62:8-30,
1969.
14. Luss, D., and N.R. Amundson, AIChE Journal. 15:194, 1969. -
15. Sofan, H.Y., AIChE Journal. 19:191, 1973; 20:416, 1974.
16. Amundson, N.R., and L.R. Raymond, AIChE Journal, 11:339, 1965.
17. Avison, N.L., R.M. Winters, and D.D. Perlmutter, "On the Kinetics of
Coal Oxidation," AIChE Journal. 25(5):773-781, 1979.
18. Kara, A.Y., A.N. Hixson, and D.D. Perlmutter, "The Oxidation of
Bituminous Coal-I, Development of a Mathematical Model," Chemical
Engineering Science. 31:815-819, 1976.
19. Mahajan, O.P. , M. Komatsu, and P.L. Walker, Jr., "low-Temperature Air
Oxidation of Caking Coals. 1: Effect on Subsequent Reactivity of Chars
Produced," Fuel. 59:3-10, January 1980.
20. Bouwman, R., and I.L.C. Freriks, "Low-Temperature Oxidation of a
Bituminous Coal. Infrared Spectroscopic Study of Samoles from a Coal
Pile," Fuel. 59:315-322, May 1980.
21. Swann, P.D., and D.G. Evans, "Low-Temperature Oxidation of Brown Coal.
3: Reaction with Molecular Oxygen at Temperatures Close to Ambient,"
Fuel. 58:276-280, April 1979.
22. Painter, P.C., R.W. Snyder, D.E. Pearson, and J. Kwong, "Fourier
Transform Infrared Study of the Variation in the Oxidation of a Coking
Coal," Fuel. 59:282-286, May 1980.
23. Cummins, J.J., and W.E. Robinson, "Thermal Degradation of Green River
Kerogen at 150° to 350° C, "Bureau of Mines Report of Investigation
7620," 1972.
24. Arnold, Jr. C., "Effect of Heating Rate on Pyrolysis of Oil Shale," In:
Industrial and Laboratory Pyrolysis. L. F. Albright and B. L. Crynes,
eds., ACS, 1978.
25. Guney, M., "Oxidation and Spontaneous Heating of Coal." METU Journal of
Pure and Applied Sciences, 5(1): 109-155, April 1972.
26. Maciejasz, Z., Archiwum Gornictwa. 4(1): Plka. Akad. Nauk. 1959.
27. Atwood, M.T., L. Goodfellow, and R.K. Kauffman, Proc. 12th Oil Shale
Symposium, Golden, Colorado (April 1979).
28. A.S.T.M., Standard D-20.30. Proposed Method on Oxidative Degradation
of Polyolefins.
47
-------
APPENDIX
-------
' IABLZ A-l. HEAT CAPACITY OF C-a RAW SHALE BASED ON INITIAL SAMPLE WIGHT
^ (—325 mesh)
T
ac
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
520
540
560
580
600
Cp
J/g°C
0.66
0.72
.73
.74
.93
.70
.70
'' .87
.91
.94
.90
.32
.75
.63
.56
.56
.56
.48
.52
.58
.69
.77
1.11
1.03
.71
.60
.63
.68
.77
^5 CP dt
J/g
9.9
24
38
53
70
86
100
116
133
152
170
188
203
217
229
240
251
262
272
283
295
310
329
350
367
381
393
406
421
A-l
-------
« •
; ' • • . TABLE A-3.
; T
; 9c
; 40
I
60
; 80
! 100
120
140
160
180
• 200
: 220
240
260
280
: 300
i 320
340
i 360
' 330
400
420
440
; 460
480
500
520
1 540
560
; 580
600
HEAT CAPACITY OF WYOMING SMITH-ROLAND SUB
ON INITIAL WEIGHT C-325 mesh}
* Cp
J/g'C
1.24
2.58
2.91
1.99
1.10
0.57
.32
.18
.13
.10
.076
.075
.10
.16
.18
. .18
.16
.23
.26
.31
.37
.42
.44
.52
.60
.66
.72
.79
.87
BITUMINOUS COAL BASED
F25 Cp dt
J/g
19
56
110
159
190
207
216
221
224
226
228
230
231
234
237
241
244
248
253
259
266
274
282
292
303
316
329
344
361
A-3
-------
*
• ' ' '. TABLE A-5.
: T
; °C
40
60
; so
100
120
140
160
180
200
; 220
240
260
280
300
320
340
360
i 330
i 400
420
440
460
430
: 500
520
! 540
! 560
1 580
1
600
HEAT CAPACITY OF PARAHO (-325 MESH)
INITIAL SAMPLE WEIGHT
Cp
J/g°C
.69
.73
.74
.75
.74
-74
.72
.75
.74
.76
.75
.73
.74
.71
.68
.65
.63
.53
.57
.55
.55
.57
.56
.55
.57
.55
.61
.64
.70
RETORTED SHALE BASED ON
^5 °P *
J/s
9.9
24
39
54
69
83
98
113
128
. 143
158 '
173
187
202
216 •
229
242
254
265
277
288
299
310
321
332
343
355
368
381
A-5
-------
TABLI A-7. HEAT CAPACITY OF POCAHONTAS #3 BITUMINOUS COAL BASED ON
IMXTXAL SAMPLE WEIGHT C-325 mesh)
T
9cv
40
60
30
100
120
140
160
180
. 200
220
240
260
280
300
320
340
360
380
400
• 420
440
460
480
500
520
540
560
580
600
Cp
J/g9c
1.11
-1.19
1.11
1.19
1.16
1.19
1.22
1.30
1.27 .
1.34
1.33
1.32
1.38
1.34
1.35
1.34
1.36
1.40
1.59
1.55
1.60
1.66
1.66
1.62
1.61
1.59
1.65
1.67
1.68
F2s CP dt
J/s
17
40
63
86
109
133
157
182
208
234
260
287
314
341
368
395
422
450
480
511
542
575
608
641
674
706
738
771
805
A-7
-------
TABLE A-9. HEAT CAPACITY OF ETTORT RETORTED SHALE BASED ON INITIAL
SAMPLE WEIGHT (-325 mesh)
T
"C
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
520
540
560
580
600
Cp
J/g*C
.99
1.1
1.0
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.0
1.0
1.0
0.96
0.92
0.87
0.90
0.97
1.1
1.1
1.2
1.3
1.4
1.6
l.S
1.5
1.6
1.6
1.6
/*5 Cp dt
J/s
15
36
57
78
101
123
146
168
139
212
233
254
274
294
312
330
348
367
388
411
435
460
488
518
548
579
610
642
674
A-9
-------
TABL£ A-ll. HEAT CAPACITY OF UTAH SAW SHALE (66 GALLON/TON) BASED 015
INITIAL SAMPLE WEIGHT C-325 niesh)
T
9C
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
520
540
560
580
600
Cp
1.4
1.4
1.4
1.5
1.5
1.6
1.6
1.6
1.6
1.6
1.5
1.4
1.3
1.3
1.2.
1.2
1.3
1.4
1.7
1.8
2,1
2.7
2.6
1.8
2.0
2.3
2.4
2.5
2.7
/£5 Cp dt
J/g
21
63
105
148
192
238
285
334
382
431 ;
476
519
560
599
636
673
711
751
799
852
911
986
1066
1128
1136
1251
1322
1395
1473
A-ll
-------
8
03
en
«•
tn ..
•* tn
«-*4 cn
a as
(. > fl£ t
_o os a (a
i o £ -
s 3 £3
.*> -» O 0
9 - C- —
a u. a a.
U
01
D
s
tn
en u
ch os >
o < -*
*" - « I
e ca a «
us -»j
tn en z c
o CM »- •-»
VJ E
9 0
r""* S 5 «
H *> 0
- 0 L
cn
-------
/•s
V
0
«—t
u.
0
Samples FARAH 31843-P148X100
Sizes 39.47 MG
Rates 2/MIN DRY AIR
Pr>oar-ams Intel-active DSC V2. 0
222 323 422
Temperature C°C)
520
600
Figure B-4. Thennogram of Paraho retorted shale !!-48 +• iQO mesh), heated at
2°C/minute in dry air.
A-15
-------
0
«—I
u_
240-
200-
160-
120-
80-
40-
0-.
-40.
Samples SU8BIT31S43-S1-325
Sizas 21.70MG
Rotai 2/MIN DRY AIR
Pr*ogr*
-------
Samplas LURGI 31643-L1-325
33. 5SMG
2/MIN WET AIR
s Expended Playback
V2. 0
222 302 400
Temperature C°C)
522 322
Figure 8-8. Thermogram of Lurgi retorted shale (-325 mesh), heated at 2°C/
minute in humid air.
A-19
-------
0
i<*4
U_
0
4..
0-.
-2'
Sa«npl« PARAHQ31S43-P1-325
Si=« 35, S2MG
Ra4;ai 2/MIN WET AIR
Progr-csms In-tar-ac-tiva DSC V2. 0
353,
220 300 400
Temperature (°C)
500
620
'iiure B-10.
Thermogram of Paraho retorted shale (-325 mesh), heated at
2°C/minute in humid air.
A - 21 '
-------
2--
r
1-4
u. a-f
-2-J-
.4..
Samples CA RAW31S43-C1-325
Si2«< 35. 1 MG
Ra-tej 2/MIN WET AIR
Progi-ams Inter motive DSC V2. 0
221,2°C
1247 J/g
224. 5*C
121. 1*C
1 1 !— ! !
100 238 300
Temperature C°C)
400
500
600
rigure B-12. Therraogram of C-a raw shale (-325 mesh), heated at 2°C/m1nute
in humid air.
A-23
-------
S«mpl«s W.KEN 31643-ei-325
Sizas 18. 4SMG
Ra-feej 2/MIN WET AIR
Proqrams Irrfe»ractiv« DSC V2. 0
SST
40--
0
.*>
a
22-
10T
-10
0
-) 1-
427.3°C
-*•
220 300 400
Temperature C8C)
500 600
Figure 8-14. Thermogram of Western Kentucky No. 9 bituminous coal (-325 mesh),
heated at 2°C/minute in humid air.
A-2S
-------
Samples UTAH RICH -325
Sizes 14.30 MG
Rates 2/MIN DRY AIR
Programs Extended Playback V2.0
DSC
H !
801
50+
40-
5 30T
0
10-
0-h
-10
H H
0 100 200 300 400 500 S00 7
Temperature CCC5
Figure 8-16. Thermogram of Utah (66 6PT) raw shale (-325 mesh),
heated at 2°C/min 1n dry air. Second test.
A-27
-------
Scanplos UTAH LEAN -325
Sisa* 28.28
2/MIN DRY A2S
Inxar«e-tiv«e DSC V2«
0
9
24
22"
18--
12-
a-.
4--
1 1
H i-
s*c
220 323 422
DSC
,
722
Figure B-18.
Thennogram of Utah (28 6PT) raw shale (-325 mesh),
heated at 2°C/min in dry atp. First test.
A-29
-------
/•s
£
3
0
0
-------
j HYTORT -323
Si2a« 25. 82 MG
2/MIN DRY AIR
i
DSC V2. 0
J
-i J-
DSC
] }-
0
0
9
IS-
8--
8--
4..
2--
-2--
-4-
203 338 483
723
Figure 8-22.
Thermogram of Hytort retorted shale (-325 mesh),
heated at 2°C/min in dry air. Second test.
A-33
-------
Scmples UNION MIX -325 17% H2Q
Siz» 53.28 MG
Re&m* 2/MIN DRY AIR
Prpcjj-cHJtt Irvt-arac-tiv® DSC V2- 3
38-t i 1 * i H
DSC
32--
2ST
0
C 22+
0
a
12-
8--
s*c
/8T3. J/g
332. 4*C
122 200 300 400 500 600 700
Figure 8-24. Thermogram of Union shale mixture (-325 mesh),
heated at 2°C/min in dry air. First test.
A-35
-------
0
0
(0
Samples UNION MIX -325 17% H2Q
Sizes 54.02 MG
Rates 2/MIN DRY AIR
Progr-ams In-ter-active DSC V2. 0
DSC
20--
16-
12-
-4-
-8'
0
338, 8*C
-^^ -5S. J/g
332.
100
200
300
400
500
500
700
Figure B-26.
Thermogram of Union shale mixture (-325 mesh),
heated at 2°C/min in dry air. Third test.
A-37
-------
Samples POCAKQNTAS £3
Sizes 25. 89
Rates 2/MIN DRY AIR
Progr-ams Extended Playback
140-
DSC
V2. 0
120-
t
108 1
80
t
0
U. 60+
-P
0
9
z i
. 40T
20-
0-
-! (-
-I 1
10Z 200 300 400 500 S00
700;
Figure B-28.
Thermogram of Pocahontas #3 bituminous coal (-325 mesh),
heated at 2°C/min in dry air. Second test.
A-39
-------
Samples 95ZPARAHQ/52UTAH LEAN
Sizes 32.55 MG
Rates 2/MIN DRY AIR
Programs Extended Playback V2. 0
6-
DSC
4-
j
i
2--
.» 01
0
£ -2-
.*>
0
01
M
»
•
m
-4..
-at
1Z5J 222 . 320 400 500 520
Temperature
700
Figure B-30. Thermogram of 95% Paraho retorted shale/5% Utah raw shale
(28 GPT) mixture (-325 mesh), heated at 2°C/minute in dry air.
A-41
-------
Samples 80%PARAHO/22%UTAH LEAN
Sizes 37.22 MG
Ra-fcas 2/MIM DRY AIR
Programs Extended Playback V2. 0
12-
DSC
0
ill! -t
0
0
x
>t
i
•12+
H »-
_l ,_
-i h
I j_
H2Z
323
402
H H
-*• !-
700.
Temper a-ture C°
Figure B-32. Thermogram of 80% Paraho retorted shale/20% Utah raw shale
(28 GPT) mixture (-325 mesh), heated at 2°C/min in dry air.
A-43
-------
Samples 78%PARAHQ/20%UTAH LEAN
33.67 MG
2/MIN DRY AIR //2% S//
Programs Extended Playback V2. 0
4+ 1 i i 1 1——I 1-
DSC
0
i—i
Is,
0
OJ
0--
-2-
-4"
-6-
-8+
-IB-
H H
1Z0 200 300 402 500 500 700
Temper atut-e C*O
Figure 8-34. Thermoqram of 78% Paraho retorted shale/20% Utah raw shale
(28 GPT)/12% sulfur mixture (-325 mesh), heated at ,2°C/min in dry air.
A-45
-------
TABLK 8-1. COMPOSITION OF EXIT GAS FROM NONADIABATIC TEST CELL AT
125°C. MEAN VALUES FROM TRIPLICATE TESTS (VOLUME %
DRY BASIS). FIRST SAMPLE SET.
Sample Type
Wyoming Sub-bituminous
Coal (-48 + 100)
Wyoming Sub-bituminous
Coal (-325)
West Kentucky £9 Bituminous
Coal (-48 +100)
West Kentucky £9 Bituminous
Coal (-325)
C-a Raw Shale
(-48 +100)
C-a Raw Shale
(-325)
Paraho Retorted
Shale (-48 +100)
Paraho Retorted
Shale (-325)
Tosco II Retorted
Shale (-48 +100)
Tosco II Retorted
Shale (-325)
Lurgi Retorted
Shale (-200 +325 );
Lurgi Retorted
Sh*1e_(-325)
02
17.45
11.56
16.15
18.03
20.55
19.88
20.32
20.90
19.90
20.43
20.68
20.62
C02
2.83
1.96
0.55
0.35
0.10
0.10
0.05
0.07
0.11
0.19
0.03
0.02
CO
0.26
0.86
0.95
0.06
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
CH4
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
.0.000
0.000
0.000
0.000
Source: Denver Research Institute.
A-47
-------
TABLE B-3. COMPOSITION OF EXIT GAS FROM NONADIA3ATIG TEST CELL AT
150*C. MEAN VALUES FROM TRIPLICATE TESTS (VOLUME Z DRY
BASIS). FIRST SAMPLE SET.
Sample Type
Wyoming Sub-bituminous
Coal (-48 + 100)
Wyoming Sub-bituminous
Coal (-325)
West Kentucky #9 Bituminous
Coal (-48 +100)
West Kentucky #9 Bituminous
Coal (-325)
C-a Raw Shale
(-48 +100)
C-a Raw Shale
(-325)
Parano Retorted *
Shale (-48 +100)
Parano Retorted
Shale (-325)
Tosco II Retorted
Shale (-48 +100)
Tosco II Retorted
Shale (-325)
Lurgi Retorted
Shale (-200 +325)
Lurgi Retorted
Shale. (-32SJ
°2
3.40
3.58
8.65
8.41
18.40
18.50
20.16
20.53
19.56
19.72
20.36
21.04
C02
5.63
6.44
1.68
1.51
0.33
0.27
0.07
0.08
0.33
0.27
0.03
0.02
CO
0.61
0.83
0.32
0.59
0.03
0.08
0.00
0.00
0.00
0.00
0.00
0.00
CH<
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.. 000
0.000
0.000
0.000
0.000
Source: Denver Research Institute.
A-49
-------
TABLE 8-5. COMPOSITION OF EXIT GAS FROM NONADIABATIC TEST CELL AT 175°C,
MEAN VALUES FROM TRIPLICATE TESTS (VOLUME Z, DRY BASIS).
FIRST SAMPLE SET.
Sample Type
Wyoming Sub-bituminous
Coal (-48 + 100)
Wyoming Sub-bituminous
Coal (-325)
02
0.12
0.03
West Kentucky #9 Bituminous 0.65
Coal (-48 -i-lOO)
West Kentucky £9 Bituminous
Coal (-325)
C-a Raw Shale
(-48 +100}
C-a Raw Shale
(-325)
Paraho Retorted
Shale (-48 +100)
Paraho Retorted
Shale (-325)
Tosco II Retorted
Shale (-48 +100)
Tosco II Retorted
Shale (-325)
Lurgi Retorted
Shale (-200 +325).
Lurgi Retorted
Sh*le (-325)
0.13
14.45
14.91
19.96
20.22
18.21
18. 98
20.85
21.00
C02
9.37
11.92
3.38
4.56
1.76
1.50
0.28
0.50
1.90
1.06
0.04
0.02
CO
1.59
1.91
1.08
1.-56
0.32
0.25
0.00
0.02
0.15
0.10
0.00
0.00
- CH4
0.021
0.036
0.017
0.039
0.003
0.001
0.000
0.000
0.000
0.000
0.000
0.000
Source: Denver Research Institute.
A-51
-------
TABLE B-7. COMPOSITION OF EXIT GAS FROM NONADIABATIC TEST CELL AT 200°C.
MEAN VALUES FROM TRIPLICATE TESTS (VOLUME Z, DRY BASIS).
FIRST SAMPLE SET.
Sample Type
Wyoming Sub-bituminous
Coal (-43 + 100)
Wyoming Sub- bituminous
Coal (-325)
02
0.02
0.01
West Kentucky #9 Bituminous 0.01
Coal (-48 +100)
West Kentucky 19 Bituminous 0.01
Coal (-325)
C-a Raw Shale
(-48 +100)
C-a Raw Shale
(-325)
Paraho Retorted
Shale (-48 +100)
Paraho Retorted
Shale (-325)
Tosco II Retorted
Shale (-48 +100)
Tosco II Retorted
Shale (-325)
Lurgi Retorted
Shale (-200 +325)
Lurgi Retorted
Shale (-325)
7.84
8.42
19.40
19.56
15,48
16.31
20.63
20.42
C02
12.64
14.83
4.35
4.09
2.95
2.13
0.31
0.45
1.46
1.58
0.04
0.03
CO
2.64
2.71
1.37
1.38
0.99
0.83
0.01
0.07
0.22
0.54
0.00
0.00
- CH4
0.035
0.081
0.027
0.035
0.032
0.014
0.000
0.000
0.000
0.000
0.000
0.000
Source: Denver Research Institute.
A-53
-------
TABLE 3-9. COMPOSITION OF EXIT GAS FROM NONADIABATIC TEST CELL AT 300°C.
MEAN VALUES FROM TRIPLICATE TESTS (VOLUME %, DRY BASIS).
FIRST SAMPLE SET.
Sample Type
Wyoming Sub-bituminous
Coal (-48 + 100)
Wyoming Sub- bituminous
Coal (-325)
West Kentucky #9 Bituminous
Coal (-48 +100)
West Kentucky §9 Bituminous
Coal (-325)
C-a Raw Shale
(-48 +100)
C-a Raw Shale
(-325)
Para ho Retorted
Shale (-48 +100)
Paraho Retorted
Shale (-325)
Tosco II Retorted
Shale (-48 +100)
Tosco II Retorted
Shale (-325)
Lurgi Retorted
Shale (-200 +325)
Lurgi Retorted
Shale (-325)
02
0.01
0.01
0.01
0.01
0.01
0.01
15.03
8.32
1.79
0.22
20.48
20.41
C02
20.13
19.40
12.22
14.59
12.42
15.24
4.99
7.61
16.45
17.68
0.16
0.29
CO
3.55
3.82
2.95
3.32
3.01
2.95
0.64
1.08
1.60
1.72
0.00
0.00
CH4
0.196
0.131
o.ios ;
0.059
0.726
0.513
0. 000
0.000
0.000
0.000
0.000
0.000
Source: Denver Research Institute.
A-55
-------
TABLE B-ll. MEAN OXYGEN CONCENTRATIONS IN EFFLUENT GAS FROM NONADIABATIC
TEST OF SECOND SAMPLE SET (VOLUME %, DRY BASIS, -325 mesh)
Sample type
Pocahontas #3 Bituminous Coal
Hytort Retorted Shale
Uttah Raw Shale (28 GPT)
Utah Raw Shale (66 GPT)
125
17.6
20.1
19.5
13.6
Temperature (°C) -
150
9.8
17.9
12.5
1.3
175
0.0
15.7
2.8
0.2
Union .Shale Mixture
(Dry)
20.6
18.0
14.6
A-57
-------
TABLE B-13. MEAN CARBON MONOXIDE CONCENTRATIONS IN EFFLUENT GAS FROM
NONADIABATIC TEST OF SECOND SAMPLE SET (VOLUME 2, DRY BASIS
-325 mesh)
Sample type
Temperature (°C)
125
150
175
Pocahontas #3 Bituminous Coal
Hytort Retorted Shale
Utah Raw Shale (28 GPT)
Utah Raw Shale (66 GPT)
Uaion Shale Mixture
(Dry)
0.05
0.05
0.15
0.45
0.07
0.32
0.61
0.07
0.08
0.16
0.16
1.1
0.23
A-59
-------
TABLE B-15. MEAN CARBON DIOXIDE CONCENTRATIONS IN EFFLUENT GAS FROM
NONADIABATIC TEST OF SECOND SAMPLE SET (VOLUME 7., DRY BASIS ,
-325 mesh)
Sample type
Temperature (°C)
125
150
175
Pocahontas #3 Bituminous Coal
Hytort Retorted Shale
Utah Raw Shale (28 GPT)
Utah Raw Shale (66 GPT)
Union . Shale Mixture
(Dry)
0.60
0.27
0.28
1.16
0.59
1.6
0.70
1.4
4.7
1.2
3.8
1.4
4.3
6.6
1.1
A-61
-------
Sample: TOSCO 31643-T1-325
Sizes 52. 29 mg
Rates 2/MIN DRY AIR
Programs Ex-cended Playback
TG
A
V2. 0
—i H
•4J
.£
91
100T
SS+
SS--
97-
36-
95--
S4--
S3-
122 222 302
400 500 600 700
Tejnpenature C°C?
Figure C-2. Thermognavimetn'c test data, Tosco II retorted shale (-325
mesh, 2 C/min heating ramp). Test 2.
A-63
-------
Sample: PARAH031643-P1-325
Size: 35. 30 mg
Rs-ce: 2/MIN DRY AIR
Program: Extended Playback V2.0
—I 1 1 1 j- 1 1 1 L.
TGA
103 r
102-
101-
i f-
95
1ZZ
500 700
Tempera-tore <°C)
Figure C-4.
ThermogravimetPic test data, Papaho retorted shale (-325 mesh,
2°C/min heating pamp). Test 1.
A-65
-------
Samples PARAHQ31543-P1-325
Sizes 42. 25 mg
Rates' 2/MIN DRY AIR
Programs Extended Playback
V2. 0
-I 1 j 1 j 1 j.
CD
1H
OJ
103
102-
101 T
100-h
93-h
98--
i
97j
TGA
-i 1 1 1 f H
1ZZ
H 1-
-j 1 )..
300 400 500 600
Temperature
700
Figure C-6. Thermogravimetric test data, Paraho retorted shale (-325 mesh,
2°C/min heating ramp). Test 3.
A-67
-------
Samples PARAH031643-P1 48X130
Sizes -42. 55 mcj
Rates 2/MIN DRY AIR
Programs Extended Playback V2. 0
103-
102-j-
101-
100-
"m
91
* SS"
98-
97-
So-
H H
H H
100 200 300 400
1 1
GA
H H
500 600
Temperature
700
Figure C-8. Thenuogravlmetric test data, Paraho retorted shale (-48 +100
mesh, 2°C/min heating ramp). Test 2.
A-69
-------
Samples CA RAW31S43 Cl -325
Sizes 30. 52 mg
Rates 2/MIN DRY AIR
Programs Extended Playback V2. 0
TGA
IFl
10
8SH
—-H h H 1 !
1ZZ 200 300
-J-
400 500 600 700
Temperature £°C}
Figure C-10.
Thermogravimetric test data, C-a raw shale (-325 mesh,
2"C/min heating ramp). Test 1.
A-71
-------
Samples CA RAW 31643 Gl -325
Sizes 29. 36 mg
Rates 2/MIN DRY AIR
Progr-ams Extended Playback V2. 3
G/
103+
f
i
S8+
i
S6+
"In
ft
dl
84t
i
+
r
90+
i
f
88
H— i 1 1 1 1
H 1
320 400 520 620 70S
Temper-atone CC'O
Figure C-12.
Thennogravimetric test data, C-a raw shale (-325 mesh,
2°C/min heating ramp). Test 3.
A-73
-------
Samples W KENS 31543 31 -325
Sizes 27. 92 mg
Ra-te: 2/MIN DRY AIR
Progr-ams Extended Playback V2. 0
0?
•*4
(9
-i i 1 f-
•H 1-
GA
H i
300
400 500 600 700
Temperature C°O
Figure C-14.
Thermogravimetric test data, Western Kentucky #9 bituminous
coal (-325 mesh 2°C/min heating ramp). Test 2.
A-75
-------
Samples LURGI 31543 LI -325
Sizes 36. 14 mg
Ra-tes 2/MIN DRY AIR
Program! Extended Playback V2. 0
TG
A
104 j-
f
103}
*•?
-p
O7
IBS |
i
t
101 f
^ 102-
:zz
zzz
322
H 1
400
500
600
700
Tempena'fe.ure
Figure C-16.
Thermogravimetric test data, Lurgl retorted shale (-325 mesh:
2eC/min heating ramp). Test 1.
A-77
-------
Samples LURGI 31S43 LI -325
Sizes 32. 92 mg
Rates 2/MIN DRY AIR
Programs Extended Playback V2. 0
•t i 1 1 1 ! i ( 1 H
104 •)-
i
i
103-i-
TGA
S7H—
IZZ 2ZZ
-4 -f-
32Z 402 S00 600 700
Temperature <°O
Figure C-18.
ThermogravimetPic test data, Lupgi petorted shale (-32!5 mesh
2°C/min heating ramp). Test 3.
A-79
-------
Sample: SUBBIT 31643 SI -325
Sizes 32. 14 mg
Rates 2/MIN DRY AIR
Program: Extended Playback V2. 0
07
140-
120-
100-
30-
50-
40-
20-
0-
H 1 H- i ! 1-
TGA
0
100 200 300 400
1 1 i 1 1 1—
500 600 700
Tempera-tore C**O
Figure C-20. Thermogravimetric test data, Wyoming subbltuminous coal (-325
mesh 2°C/min heating ramp). Test 2.
A-81
-------
Sample: POCAHQNTAS03
Size: 32. 45 mg
Rate: 2/MIN DRY AIR
Program: Ex-tended Playback V2. 0
'07
140-
120 +
100T
80-
60T
40--
20-
TGA
100
200
300
400
4 1 1 1
500 600 700
Temperature <°C)
Figure C-22.
Thermogravimetric test data, Pocahontas #3 bituminous coal
(-325 mesh 2°C/min heating ramp). Test 1.
A-83
-------
CM
I
H H
00
(O
s
(O
en
(M
03
53 Q}
** i.
™ J
a
it
...(0
••CM
O3
Figure C-24.
Thermogravlmetric test data, Pocahontas #3 bituminous coal
(-325 mesh 2°C/min heating ramp). Test 3.
A-85
-------
Sample: HYTORT -325
Size; 29. 50 mg
Rates 2/MIN DRY AIR
Procjr-ams Extended PI a
TGA
-Jj
05
•«•«
ID
101"
100"
99-
98 T
97-
98-
95-
34'
H 1-
1 - 1
100 200 300
400 500 600
Temperature
700
Figure C-26.
Thermogravimetric test data, Hytort retorted shale (-325) mesh
2°C/min heating ramp). Test 2.
A-87
-------
Samples UTAHLEAN -325
Size: 25, 99 mg
Rates 2/MIN DRY AIR
Programs
TGA
j:
en
•*4
(0
130-
120--
110-
100-
90-
80-
70-
S3-
103 200 300
400 500 600 700
Temperature C*C)
Figure C-28. Thermogravinietric test data, Utah raw shale (28 6PT) (-325
mesh 2°C/min heating ramp). Test 1.
A-89
-------
Samples UTAHLEAN -325
Sizes 32. 16 mg
Rates 2/MIN DRY AIR
Programs Extended Playba
TGA
130
120
,r
•rt
-------
Samples UNION MIX -325 17%H2Q
Sizes 46. 82 mg
Rates 2/MIN DRY AIR
TGA
100
92
88
03 84+
•**
10
76-
72-
H h
H 1-
200 300
! 1 ! ! H ; i -H
400 500 600 700
Temperature (°C5
Figure C-32. Thermogravimetric test data, Union shale mixture
(-325 mesh 2 C/min heating ramp). Test 2.
A-93
-------
.Samples UTAH RICH -325
Sizes 20. 64 mg
Rates 2/MIN DRY AIR
Programs Ex-tended Playback V2.
102
TGA
80-
70-
"en 50- •
"3
50-
40-
30-
100 200
300
s - 1
400 500 500 700
Temperature C°O
Figure C-34.
ThennogravimetPic test data, Utah raw shale (66 GPT)
(-325 mesh 2°C/min heating ramp). Test 1.
A-95
-------
Sample: UTAH RICH -325
Size: 31. 70 mg
Rates 2/MIN DRY AIR
Programs Extended Playback V2. 0
TGA
100
90-
80-
70r
07 80"
50-
40-
32 T
' '
1 - H
-i f-
200 300 400 500 600 700
Temperature C°O
Figure C-36.
Thermogravimetric test data, Utah raw shale (66 GPT)
(-325 mesh 2°C/min heating ramp). Test 3.
A-97
------- |