EPA-600/2-77-206
October 1977
Environmental Protection Technology Series
PILOT PLANT STUDY OF CONVERSION
OF COAL TO LOW SULFUR FUEL
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park. North Carolina 27711
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This report has been assigned to the ENVIRONMENTAL PROTECTION TECHNOLOGY
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EPA-600/2-77-206
October 1977
PILOT PLANT STUDY OF CONVERSION
OF COAL TO LOW SULFUR FUEL
by
Donald K. Fleming and Robert D. Smith
Institute of Gas Technology
3424 South State Street
Chicago, Illinois 60616
Contract No. 68-02-1366
ROAP No. 21AFJ-040
Program Element No. 1AB013
EPA Project Officer: Lloyd Lorenzi, Jr.
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, N.C. 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or recommendation
for use.
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EXECUTIVE SUMMARY
The purpose of this program is to develop, on a bench and pilot scale,
the operating conditions for the key step in the IGT process to desulfurize
coal by thermal and chemical treatment. This process, to date, uses the
"sulfur-getter" concept. A sulfur-getter is defined as a material that has
a greater chemical affinity for sulfur than the coal has. Lime has been
selected as the sulfur-getter for this program.
The program reported here was divided into two phases. In Phase I, the
problem was directly attacked on a pilot-unit scale. The results of this work
indicated that the program should be redirected (Phase II) to smaller-scale
test apparatus so that more basic data could be obtained for eventual scale-up
to pilot scale.
In the initial project phase, a coal-lime mixture was experimentally
treated at atmospheric pressure with a reducing gas in a heated, fluidized-bed
reactor. This reactor could treat up to 200 Ib/hr* of mixture to temperatures
of 1200°F. The coal used in the in:
seam and contained about 3% sulfur.
of 1200°F. The coal used in the initial tests was from the Illinois No. 6
Work in the initial program phase resulted in the discovery that less
sulfur was removed than expected at these conditions. Two factors were
believed responsible:
1. The coal heat-up rate in the fluidized bed was nearly instantaneous,
which appeared to cause organic sulfur fixation.
2. The coal showed signs of weathering; therefore, the total sulfur content
was not readily available for hydrogen treatment.
At this point, the program was redirected (Phase II) to the operation of
smaller-scale test units that featured controlled heat-up rates. The smaller-
scale units also permitted an increased number of tests over a broader range
of conditions, with savings in time and manpower. Coal samples from several
mines throughout the country were obtained for tests in this equipment.
A coal-lime mixture was treated with hydrogen, in batch-type reactors,
to temperatures of 1500°F. Heat-up rate, terminal temperature, residence
time, and particle size were the variables tested.
* English units are commonly used in this document in areas of engineering
development; SI units are used in more basic research areas. Refer to
Conversion Table page xi.
iii
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Preliminary tests eliminated the Western coals (i.e., subbituminous and
lignite) because the sulfur content of the raw coal was low and not readily
amenable to treatment. Also, the preliminary tests indicated that the coals
from the Midwestern and Eastern United States required pretreatment to prevent
caking during hydrotreating. This is accomplished by heating the fluidized
coal at atmospheric pressure to 750°F in the presence of oxygen.
On the basis of the preliminary tests with several coals and the relative
abundance of the types of coal, a coal from the Western Kentucky No. 9 seam
was chosen for complete characterization. This coal is from the Illinois
basin and contains over 3% sulfur. Tests were run covering a wide range of
the parameters listed. These tests prove that acceptable sulfur levels were
attained at treatment temperatures of 1500°F. The higher temperatures result
in significant tar removal and some gasification of the coal. These effects
necessitate further research into quantity, chemical makeup, and handling of
gas' and liquid streams.
The testing resulted in the discovery that treatment with lime does not
capture all the sulfur that is released from the coal. A more thorough
examination of the effectiveness and benefits of lime is required in future
work.
A conceptual process design, based on laboratory and bench-scale data, is
presented. That process will produce a solid fuel that can be burned directly
in conformance with Federal EPA New Source Performance Standards (NSPS).
iv
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TABLE OF CONTENTS
Executive Summary iii
List of Figures vi
List of Tables viii
Conversion Factors xi
Symbols xii
Obj ective 1
Introduction 2
Materials 3
Coal 3
Acceptor 3
Mixture 10
Thermodynamic Study 11
Equipment 29
Pilot Unit 29
Batch Reactor 29
Thermobalance 29
Modified Batch Reactor 38
Laboratory Procedures 42
Test Runs — Start of Phase I 45
Batch Reactor 45
Pilot-Unit Tests 45
Test Results - Batch Unit 46
Test Results — Pilot Unit 52
Analysis of Test Results 61
Conclusions 61
Kinetic Studies of Outside Data 63
Program Redirection — End of Phase I, Start of Phase II 70
Selection of Coal for Extensive Study 74
Thermobalance Tests — Western Kentucky No. 9 80
Thermobalance Tests — Pittsburgh Seam, West Virginia 94
Batch Reactor Tests — Western Kentucky No. 9 112
Batch Reactor Tests — Pittsburgh Seam, West Virginia 115
Gas Sample Analysis 127
Batch Reactor 127
Pilot Reactor Runs 127
Modified Batch Reactor 127
Conclusions 136
Process Concept 137
Future Work 139
Necessity for Lime 139
Other Coals 139
Pilot Unit 139
Overall Concept Design 139
References Cited 140
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LIST OF FIGURES
Number Page
1 Fluidization Characteristics of Illinois No. 6 Coal,
—10 Mesh 6
2 Fluidization Characteristics of Tymochtee Limestone ..... 7
3 Fluidization Curve for Mixed Coal-Limestone (25% +14
Mesh Limestone and 75% —10 Mesh Coal) 9
4 Thermodynamic Equilibrium in Coal-Getter Process for
FeS + CaO and FeS + H_ Reactions 10
5 Thermodynamic Equilibrium in Coal-Getter Process for
H-S + CaO Reactions 11
6 Thermodynamic Equilibrium in Coal-Getter Process for
FeS + CaCO- Reaction 12
7 Thermodynamic Equilibrium in Coal-Getter Process for
CaCO, and CaS + H»0 Reactions 13
8 CaS-CaO-C02-H20 System 27
9 CaO-CaS-C02 System . 28
10 Reactor Flow Sheet 30
11 Distribution Plate Detail 31
12 Distributor. Plate 32
13 Distributor Nozzles 33
14 Flow of H» in Distributor Nozzle 34
15 Distributor Plate Nozzle Pressure Drop Versus Reactor
Gas Velocity 35
16 Treated Coal Receiver 36
17 Batch Coal Desulfurization Equipment 37
18 Flow Diagram of Thermobalance System 39
19 Modified Batch Reactor 40
20 Modified Batch Reactor Flow System 41
21 Laboratory Procedure for the New Analytical Method 44
22 Percent Pyritic Sulfur in Treated Coal 62
23 Percent Total and Organic Sulfur in Treated Coal 62
vi
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LIST OF FIGURES (Continued)
Number Page
24 Removal of Pyritic Sulfur 64
25 Removal of Nonfixed Organic Sulfur 64
26 Fixation of Available Organic Sulfur as a Function of
Temperature and Lime Content 65
27 Fixation of Organic Sulfur With Excess CaO Present 65
28 Fixation of Organic Sulfur With Insufficient CaO Present . . 66
29 Coal Sulfur Fractions Heated Without Lime in the
Presence of Hydrogen 68
30 Coal Sulfur Fractions Heated With High Lime Additions
in the Presence of Hydrogen 69
31 Thermobalance Char-Sulfur Content at 5 F/min Heating
Rate 102
32 Thermobalance Char-Sulfur Content at 10° and 20°F/min
Heating Rates 103
33 Batch Reactor Char-Sulfur Content 123
34 Flow Sheet for Proposed Process 138
vii
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LIST OF TABLES
Number
1 Raw Coal Analysis ...................... 4
2 Sulfur in Coal by Type ................... 5
3 Limestone Analysis ..................... 8
4 Case I (0.3 mole CaS, 1 mole CaO, 3 moles H20) ....... 18
5 Case II (0.3 mole CaS, 3 moles H-O, 3 moles C02, 1 mole CaO). 19
6 Case III (1 mole CaO, 0.3 mole CaS, 3 moles CO,) ...... 21
7 Case IV (0.3 mole CaS, 1 mole CaO, 3 moles S02) ....... 23
8 Case V (0.3 mole CaS, 1 mole CaO, 1 mole 02) ........ 26
9 Float Portion of Batch Tests ................ 47
10 Sink Portion of Batch Tests ................. 49
11 Batch Test Run 20 ...................... 51
12 Batch Test Gas Sample Analysis ............... 51
13 Pilot-Unit Run Conditions .................. 53
14 Size Analyses of Pilot-Unit Test 2 ............. 54
15 Sample Analyses for Run 3 (N2, 600°F, Without Lime) ..... 55
16 Sample Analyses for Run 4 (N2, 800°F, Without Lime) ..... 55
17 Pilot-Unit Run 5 (NZ, 825°F) ................ 56
18 Pilot-Unit Run 6 (N2 and H2> 850°F, 50 Ib/hr Coal) ...... 56
19 Time-Temperature Matrix for Pilot-Unit Runs ......... 57
20 Pilot-Unit Run 7 (H2, 1000°F, 50 Ib/hr Mix) ......... 58
21 Pilot-Unit Run 7, Further Detail .............. 58
22 Pilot-Unit Run 8A (H2> 900°F, 50 Ib/hr Mix) ......... 59
23 Pilot-Unit Run 8B (H , 750°F, 50 Ib/hr Mix) ......... 59
24 Pilot-Unit Runs 9A and 9B (H2, 950°F, 50 Ib/hr Mix) ..... 60
25 Pilot-Unit Run 9C (H2, 800°F, 50 Ib/hr Mix) ......... 60
26 Basic Data — Thermobalance Runs ............... 71
27 Thermobalance Runs — Reduced Data . ............. 72
28 Thermobalance Run Data (Illinois No. 6 Coal) ........ 75
viii
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LIST OF TABLES (Continued)
Number Page
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
Thermobalance Run Data — Various Coals
Thermobalance Run Data (Western Kentucky No. 9)
Thermobalance Run Data (Pretreated Western Kentucky No. 9) .
Thermobalance Run Data (Pretreated Western Kentucky No. 9
Coal, 900°F)
Thermobalance Run Data (Pretreated Western Kentucky No. 9
Coal, 1500°F)
Thermobalance Run Data (Pretreated Western Kentucky No. 9,
1500°F, 30 min)
Thermobalance Run Data (Pretreated Western Kentucky No. 9,
1500°F, 0 min)
Thermobalance Run Data (Pretreated Western Kentucky No. 9,
10°F/min, 1500°F)
Thermobalance Run Data (Pretreated Western Kentucky No. 9,
20°F/min, 1500°F)
Thermobalance Run Data (Pretreated Western Kentucky No. 9,
1300°F)
Thermobalance Run Data (Pretreated Western Kentucky No. 9,
1600°F)
Thermobalance Run Data (Pretreated Pittsburgh Seam, W. Va.,
1500°F, 0 min)
Thermobalance Run Data (Double Pretreated Pittsburgh Seam,
W. Va., 1500°F)
Thermobalance Run Data (Pretreated Pittsburgh Seam, W. Va.,
1500°F, 0 min)
Thermobalance Run Data (Pretreated Pittsburgh Seam, W. Va.).
Batch Reactor Run Data (Western Kentucky No. 9)
Batch Reactor Run Data (Pretreated Western Kentucky No. 9,
900°F)
Batch Reactor Run Data (Pretreated Western Kentucky No. 9,
1500°F)
Batch Reactor Run Data (Pretreated Western Kentucky No. 9,
1300°F)
Batch Reactor Run Data (Pretreated Western Kentucky No. 9,
10° and 20°F/min)
Batch Reactor Run Data (Pretreated Western Kentucky No. 9
Rapid Heatup)
76
81
85
86
87
90
92
95
96
99
101
105
106
109
110
113
114
116
118
120
122
ix
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LIST OF TABLES (Continued)
Number Page
50 Batch Reactor Run Data (Pretreated Pittsburgh Seam,
W. Va.) 124
51 Batch Reactor Gas Analysis — Illinois No. 6 Coal 128
52 Pilot Reactor Gas Analysis — Illinois No. 6 Coal 129
53 Modified Batch Reactor Gas Analysis (800°F) — Pretreated
Western Kentucky No. 9 Coal 130
54 Modified Batch Reactor Gas Analysis (1200°F) — Pretreated
Western Kentucky No. 9 Coal 131
55 Modified Batch Reactor Off-Gas Analysis (1500°F) -
Pretreated Western Kentucky No. 9 Coal 132
56 Modified Batch Reactor Off-Gas (800°F) — Pretreated
Pittsburgh Seam (W. Va.) Coal 133
57 Modified Batch Reactor Off-Gas (1200°F) - Pretreated
Pittsburgh Seam (W. Va.) Coal 134
58 Modified Batch Reactor Off-Gas (1500°F) - Pretreated
Pittsburgh Seam (W. Va.) Coal 135
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CONVERSION FACTORS
Non SI Units
atmosphere
Btu
Btu/lb
cal
°C
°F
°F/min
foot
inch
in H20
in H20/ft
pound
psi(a)
SCF/hr
Operation
x 101325
x 1055.87
x 2327.794888
x 4.19002
+ 273.15
(5/9)(TF + 459.67)
x .0092592
x 0.3048
x 0.0254
x 249.082
x 2988.98
x 0.45359237
x 6894.7572
x 0.000007865790722
SI Unit
N/m2
J
J/kg
J
K
K
K/s
m
m
N/m2
N/m3
kg
N/m2
m3/s
Mesh
An Empirical Measure of Particle Size:
U.S.
Mesh
10
12
14
20
30
40
60
80
100
Opening Size
mm
2.00
1.68
1.41
0.84
0.59
0.42
0.25
0.177
0.149
xi
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SYMBOLS
Symbol Meaning
Cp Heat capacity
K Equilibrium constant (when not preceded
by a numeral)
N Solution normality
xii
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OBJECTIVE
The objective of the program is to determine experimentally, on a bench-
and pilot-unit scale, the operating conditions for the key step in the IGT
process to desulfurize coal by thermal and chemical means. The current NSPS
for solid fossil-fuel combustion has largely been observed by switching to
low-sulfur fuels. Achieving the goals of this program will increase the
supply of low-sulfur fuels.
-------
INTRODUCTION
Researchers at the Institute of Gas Technology (IGT) have conceived a
process for the removal of sulfur from coal by thermal and chemical means.
A patent has been granted on this process and assigned to IGT. The objective
of the current work in this program has been to develop the key step of that
process.
The process incorporates low-pressure treatment of the coal in a reducing
atmosphere, forming hydrogen sulfide (H2S). The equilibrium partial pressure
of H2S over coal is not high, even at elevated temperatures. In this process,
therefore, a "sulfur-acceptor" ("sulfur-getter") is added to the coal-
reductant system. The sulfur-getter is defined here as a material that has a
greater chemical affinity for sulfur than coal has, thus overcoming the
equilibrium limitations. One example of a sulfur-getter is lime. Hydrogen
sulfide has a much lower equilibrium partial pressure over lime than it has
over coal; therefore, the reducing gas will react with the sulfur in the coal,
forming EUS. The H«S, however, will react almost immediately with the lime.
In this system, the sulfur is transferred from the coal to the lime with an
H~S intermediate.
The first step in the overall chemical reaction is to release the sulfur
from the coal as H«S. However, the sulfur in the coal is not a distinct
chemical species, but exists in many forms that react with hydrogen at
varying temperatures. The H^S can also back-react with the coal, forming
stable coal-sulfur complexes. The program is designed to test the removal of
sulfur from the coal at varying temperatures, to determine the severity of
treatment required for manufacturing an environmentally satisfactory solid-
fuel product. The sulfur-getter was included in the system to enhance the
sulfur-removal rate and minimize the back-reaction.
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MATERIALS
COAL
The coals used in the project, their proximate and ultimate analyses,
and sulfur-by-type analyses are presented in Tables 1 and 2. Two coals from
the Illinois No. 6 seam are listed. The first of the Illinois coals was
originally used in the project because it was readily available. However,
this coal was severely weathered, and sulfur removal proved difficult. The
second coal sample was therefore obtained for additional testing. These coals
provided a wide range of sulfur content. Their rank ranged from the low-sulfur
Western coals to the higher-sulfur-bearing Midwestern and Eastern coals.
Fluidization characteristics were evaluated on a sample of Illinois No. 6
coal scalped at —10 mesh. These fluidization tests were made in a 1.5-inch-
diameter Lucite apparatus, utilizing air at ambient temperatures. The
resulting fluidization curve is shown in Figure 1. The apparent minimum
fluidization velocity of 0.03 ft/s is lower than expected and is probably
caused by the wide range of particle sizes. The velocity required for sus-
pending the larger particles was about 1 ft/s, but they do not greatly
influence the pressure drop across the bed or the apparent minimum fluidization
velocity. Better fluidization and mixing were expected in the pilot unit
because of the distribution-plate design and the continuous flow of material.
In the second phase of the program, after extensive screening by small-
scale thermobalance tests of all the coals listed, Western Kentucky No. 9
coal was selected as a good sample for complete testing. Later, a coal from
West Virginia was also examined. Most Western coals could be eliminated from
testing because their initial sulfur content was low; also, the high oxygen
content of the Western coals was attacked by the reductant, causing process
inefficiency. Preliminary treatment was discovered to be necessary to prevent
agglomeration of the selected coals at the operating conditions of the
proposed system. The pretreatment conditions were determined for these coals,
as discussed starting on page 80.
ACCEPTOR
Limestone (CaCO~) was the original acceptor considered for this program.
The laboratory analysis of Tymochtee limestone, obtained from Huntsville,
Ohio, is presented in Table 3. This material was relatively coarse, and
fluidization characteristics (Figure 2) of both —14 and +14 mesh were evaluated.
The —14 mesh exhibited characteristics similar to the —10 mesh coal, but at
slightly higher velocities. The +14 mesh material could not be fluidized at
gas velocities less than 1 ft/s.
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TABLE 1. RAW COAL ANALYSIS
Proximate Analysis
Moisture
Volatile Matter
Ash
Fixed Carbon
Total
Ultimate Analysis, (Dry)
Ash
Carbon
Hydrogen
Sulfur
Oxygen
Nitrogen
Total
111.
No. 6*
3.72
36.1
9.8
50.38
100.00
10.20
69.32
4.76
2.62
11.89
1.21
W. Ky.
No. 9
5.9
33.4
14.8
45.9
100.0
15.68
67.47
4.66
4.06
6.75
1.38
Ind.
No. 5
9.0
34.5
11.9
44.6
100.0
13.10
68.60
4.63
3.92
8.32
1.43
Pittsburgh Mont. N. D.
Seam Subbituminous Lignite
Pa.
wt
1.5
27.6
30.8
40.1
100.0
31.29
56.67
3.81
1.45
5.63
1.15
W. Va.
7.7
33.8
10.8
47.7
100.0
10.91
73.43
4.89
3.01
6.45
1.31
17.6
35.7
3.6
43.1
100.0
4.38
72.42
5.01
0.84
16.36
0.99
24.5
32.0
6.3
37.2
100.0
8.30
64.67
4.17
0.64
21.22
1.00
111.
No. 6 t
5.8
24.8
35.7
33.7
100.0
37.88
49.08
3.38
1.20
7.31
1.15
100.00
100.00
100.00
100.00
100.00
100.00
100.00
100.00
* Weathered coal.
t New sample.
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TABLE 2. SULFUR IN COAL BY TYPE
Ul
111.
No. 6*
0.00
0.32
0.89
1.79
W. Ky.
No. 9
0.00
0.07
2.30
0.97
Ind.
No. 5
0.07
0.00
2.02
1.24
Pittsburgh
Seam
Pa. W. Va.
i- 07
Wt 7o
0.04 0.05
0.00 0.00
1.08 1.49
0.26 1.37
Mont. Sub-
bituminous
0.00
0.00
0.29
0.37
N.D.
Lignite
0.04
0.00
0.21
0.28
111.
No. 6t
0.00
0.00
1.14
0.04
Sulfur, By Type
Sulfide
Sulfate
Pyritic
Organic
Total 3.00 3.34 3.33 1.38 2.91 0.66 0.53 1.18
Note: The total sulfur presented here does not agree with the values presented in Table 1. The analysis
of sulfur-by-type uses different laboratory procedures that are more accurate. Therefore, the total
sulfur values from this table were used for data analysis.
* Weathered coal.
t New sample.
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20
*. 10
•*—
•v
O 8
CM
I
c 6
*
O O
0.007 0.01
0.008
0.02
DD
0.04 0.06 0.08 0.1 0.2
AIR VELOCITY, ft/s
0.4 0.6 0.8 1.0
2.0
A-102-924
Figure 1. Fluidization characteristics of Illinois No. 6 coal, —10 mesh.
-------
AP/L, in. H20/ft
TO
e
^
ro
NJ
N
03
O
ff
pi
H
01
rt
CO
o
o
o
(D
(D
CO
rt
O
3
fD
m £
o
o
o
ro
(0
ro
m
-------
TABLE 3. LIMESTONE ANALYSIS
Proximate Analysis, wt %
Moisture 3-3
Ultimate Analysis, wt %
CaO 30.5
MgO . 18-6
C02 42.93
s 0,26
Acid Insoluble -7.7
Screens, % retained on
10 29.5
14 16.0
20 16.8
30 6,9
40 5.4
60 5-8 .
80 3.3
100 1.5
200 4.8
325 3.1
Pan 6.9
Bulk Density, Ib/cu ft 106.0
True Density, g/ml at 25°C 2.717
The original process concept suggested that a coarse-sized limestone and
finer coal would be desirable because this type of mixture would provide easier
separation after treatment. A mixture of 3 parts —10 mesh coal and 1 part
+14 mesh limestone was fluldized, with the results shown in Figure 3. Nearly
quantitative segregation occurred in this test, indicating that separation
was feasible, but that co-fluidization, required for the pilot unit, was poor.
A smaller size consist was required for the limestone. As a result, ease of
separation was sacrificed for the better mixing required in the pilot unit,
and other separation techniques would require evaluation.
Later thermodynamic studies indicated that quicklime (CaO) would be a
better acceptor than limestone, because lower temperatures and energy inputs
are theoretically required for both the initial desulfurization reaction and
-------
VO
0.01
O
D A O
D
O
S
D a a
A
\
A
ko
\6
S
Oi^
0.02
0.04 0.06 0.08 O.I 0.2
AIR VELOCITY, ft/s
0.4
0.6 0.8 I
A-II2-998
Figure 3. Fluidization curve for mixed coal-limestone
(25% +14 mesh limestone and 75% —10 mesh coal).
-------
the acceptor regeneration. The program was therefore redirected to use quick-
lime as the acceptor. Since limestone and quicklime are physically similar,
smaller particle lime must be used for adequate mixing.
MIXTURE
In the first tests, a mixture of 4 parts coal and 1 part lime by weight
was used for the feed. This ratio was chosen to provide several (approximately
4 to 5) times the stoichiometric lime-sulfur requirement. Laboratory results
from the first test runs indicated that the lime had hydrated and carbonated
from the coal moisture and handling. The ratio was changed to 2 parts coal
and 1 part lime for subsequent tests to allow sufficient lime for these experi-
mental side effects and still have excess lime for desulfurization.
The size consist chosen for the two constituents was based on the
fluidization tests discussed above. Coal was screened at —104-80 mesh and the
lime at —20+60 mesh. The fines were removed to prevent excess dust loading
of the exit gas system.
10
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THERMODYNAMIC STUDY
A thermodynamlc study of the C-H-S-0-Ca-Fe system was made to a) indicate
the theoretical limitations of the possible reactions, b) aid in selecting
sulfur-getter material and getter/coal ratio, and c) provide an input for the
later kinetic studies.
Graphs showing the log of the equilibrium constant, K, as a function of
temperature for various system reactions are shown in Figures 4 to 7. The
data for these graphs were calculated independently by two individuals using
different data sources and calculation techniques. The results agreed closely
and differed only because of variations of material properties given in
different references. The accuracy of the calculations is determined by com-
parison of the calculated equilibrium constant with literature values.
Equilibrium data are not available for the coal-sulfur system as it exists
naturally. Sulfur exists in coal in many forms (pyrite, sulfide, sulfate,
organic), and the organic coal-sulfur chemistry is complex.
However, the literature indicates that much of the organic sulfur in the
coal is eliminated more readily than the pyritic sulfur. An even more
difficult sulfur-removal problem is the final decomposition of the ferrous
sulfide that is formed when iron pyrite is desulfurized. The decomposition
of the ferrous sulfide, therefore, was selected as the basis for the thermo-
dynamic study.
Figure 4 presents the free energy calculation for the reaction —
FeS + H2 *4 Fe + H2S
This calculated graph agrees well with the experimental data obtained by
Rosenquist (3). His data, over the range of 932° to 1410°F, may be represented
by-
PH S
"
+ 0.179
where T is the temperature expressed as °F. However, significant variations
in the value of the calculated equilibrium constants can occur, depending on
the literature source for the thermodynamic constants of FeS. For example,
Rosenquist determined a AF for the formation of FeS at 298 K as -22,700 cal/
g-mol. Other published values are —
Kubaschewski and Evans (2) —24,500
Rossini, et al. (4) —23,200
Clark Q.) -24,311
11
-------
400 600 800 1000——__I200 1400 1600 1800
A-II2-I05E
Figure 4. Thermodynamic equilibrium in coal-getter process
for FeS + CaO and FeS + H- reactions.
-------
8
26
24
22
20
18
16
14
12
10
8
6
4
2
0
-2
-4
200
400
600
800 1000
T,°F
1200
1400
1600
1800
A-II2-I05T
Figure 5. Thermodynamic equilibrium in coal-getter process for H-S + CaO reactions.
-------
1800
A-II2-I054
Figure 6. Thermodynamic equilibrium in coal-getter process for FeS + CaC03 reaction.
-------
1800
A-112 -1055
Figure 7. Thermodynamic equilibrium in coal-getter process for CaCO., and CaS + H?0 reactions.
-------
These differences alone can cause log K to vary by 0.5 at 900°F. In addition,
heat capacity (C-) data differ from various sources, and this effect can cause
additional changes of 0.6 in the value of log K.
Another thermodynamic problem is the differing choice of standard states
for sulfur in the literature. Care must be exercised in the thermodynamic
calculations of sulfur compounds because of this problem.
The graph (Figure 4) for the hydrotreatment of FeS indicates that the
equilibrium partial pressure of H2S is very low, even at elevated temperatures.
The equilibrium constant, K, for the reaction is equivalent to the ratio of
the partial pressure of H2S to H-. Even at elevated temperatures, the equili-
brium constant is less than about 10; therefore, the equilibrium partial
pressure of H0S is low. Excessive hydrogen recycle rates would be required to
completely desulfurize even small quantities of pyritic coal if the hydrotreating
process alone were employed.
The sulfur-getter concept was based on the results presented in the
previous paragraph. The coal could not be economically desulfurized by
hydrogen alone. However, if a "sulfur-getter" — a material with a greater
thermodynamic affinity for sulfur — were introduced into the system, the back
pressure of the H~S would be reduced and the iron would desulfurize. Lime-
stone is an example of this getter:
He _i_ PaPH 3^ Pa Q -4- H C\ 4- PPi
n O ~ OdVlWrt f^- V^CLO I flnVJ ~ V^\J«
As graphed in Figure 7, the reaction should proceed to the right at tempera-
tures in excess of 800°F. However, when the generation of H_S is included —
FeS + H2 £ H2S + Fe
gives
and
FeS + H2 + CaC03 <± H20 + C02 + CaS + Fe
FeS + H2 + 2CaC03 £ Ca(OH>2 + CaS + Fe + 2CO
log K values of —2.6 and —6.4 result at 1000°F and are lower at reduced
temperatures (Figure 6) .
Reactions with Ca(OH)2 are more favorable, but those with quicklime —
and
FeS + H2 + CaO «* CaS + HO + Fe
FeS + H2 + 2CaO ** Ca(OH>2 + CaS + Fe
are both favorable in the temperature range to be studied (Figure 4). The
second reaction is favored at temperatures lower than 875°F, indicating that
the required lime addition is double that expected for simple conversion to
CaS. Quicklime is therefore a better acceptor than limestone, so quicklime
was used in the test program.
16
-------
Regeneration of the CaS was also studied. Several cases were analyzed
thermodynamically and are shown in Tables 4 through 8 and Figures 8 and 9.
Case I is regeneration of the CaO and CaS solid mixture with HO. At
temperatures of 300 to 500 K, all the CaO is converted to Ca(OH)2. Conversion
of CaS to Ca(OH)2 decreases with the increased temperature. Table 4 shows the
equilibrium composition of the !CaO:0.3CaS:3H20 system. At 300 K (80°F) the
operation must be in a vacuum if the water is to remain in the vapor phase;
the maximum total pressure at which water can be in the gaseous phase is 0.5320
psia. Only 30% of the CaS is converted to Ca(OH)2 at this condition. Com-
plete CaS conversion to Ca(OH>2 is possible at these temperatures if the oper-
ation is done at higher pressure. For complete reaction at 212°F, the pressure
should be 15.95 psia, and at 440°F the pressure required is 2584 psia.
Case II treats the CaO-CaS mix with both H~0 and C02. In this system,
all the CaO goes to CaC03 between 700 and 1110 K. At 1300 K, the partial
pressure of C02 must be above 5.0505 atmospheres, to prevent the decomposition
of the CaCOg. The conversion of CaS decreases with the temperature. The CO +
S2 formation does not start until the temperature reaches 1100 K. At 1300 K
the reaction —
CaS + C02 -4 CaO + CO + 1/2S
is more favorable, and the conversion of CaS is increased. The results are
shown in Table 5 and Figure 8.
Case III, treatment of the CaO and CaS with C0_ only, results in con-
version of all the CaO to CaCO- between 700 and 1100 K. The conversion of
CaS to CaCOo decreases as the temperature increases from 700 to 1100 K. The
presence of CO and S2 is not possible in the resulting gaseous phase up to
1100 K. However, at 1300 K, the reaction —
CaS + C02 -> CaO + 1/2S2 + CO
takes place, with the decomposition of CaS to CO and 1/2S2. This increases
the relative conversion of CaS as the temperature increases from 1100 to
1300 K. Figure 9 and Table 6 tabulate the data.
Cases IV and V, treatment with 0- and S02, respectively, were not desirable
because of the formation of CaSO, . These results are shown in Tables 7 and 8.
Considering these studies, the most favorable one is the first, i.e., regener-
ation with H20 only, because Ca(OH)2 requires lower heat and temperature to
regenerate to CaO than the CaCO» does.
17
-------
TABLE 4. CASE 1(0.3 MOLE CaS, 1 MOLE CaO, 3 MOLES H00)
oo
Temperature
Reaction K Values
CaO + HZO - Ca(OH)z
CaS + 2HzO - Ca(OH)j + H2S
Pressure, psia
Composition, mole
Solid Phase
Ca(OH)j
CaS
Liquid Phase
H20
Gas Phase
HZO, mole
H20, %
H2S, mole
HZS, %
CaS Conversion, %
300 K (80 T)
373 K (212T)
500 K (440 T)
J4.7
1.3
--
1.38929
0.01071
3.452
3.00
96.554
100.00
Very large
1.469
0.5320*
1.092
0.208
--
1.816
95.18
0.092
4.82
30.7
1.
0.
14.7
1.Z8559
0.01441
--
1.4288
83.34
0.28559
16.66
95.20
0016 X 104
23982
15.95* 147.0
1 . 30 1 . 30
—
..
1 . 40 1 . 40
82.35 82.35
0.30 0.30
17.65 17.65
100.00 100.00
14.7
1.00295
0.29705
--
1.9941
99.85
0.00295
0.15
0.98
8.03 X
1.48 X
147
1.0592
0.2408
--
1.8816
96.95
0.0592
3.05
19.73
10J
io-3
1470
1.20745
0.09255
--
1.5851
88.43
0.20745
11.57
69.15
2584
1.3
--
--
1.4
82.35
0.3
17.65
100.00
Pressure at which all water can remain in vapor phase.
Pressure above which all CaS can be converted into Ca(OH)2.
B-103-1600
-------
TABLE 5. CASE
Temperature
Reaction K Values
CaO + CO2 -* CaCO3
CaS + 2CO2 - CaCO3 + COS
CaS + 2CO2 - CaCO3 + CO + 1/2 S2
CaS + 2CO2 - CaCO3 + CO + 1 /8 S8
CaS + H2O + CO2 - CaCO3 + H2S
CaS + H2O -* CaO + H2S
CaS + CO2 - CaO + CO + 1 /2 S2
Pressure, atm
Composition, mole
Solid Phase
CaCO3
CaO
CaS
Gas Phase, mole
CO2
COS
H2S
H20
CO
Gas Phase, %
CO2
COS
H2S
H20
CO
CaS Conversion, %
II (0.3 MOLE CaS, 3 MOLES H20, 3 MOLES C02> 1 MOLE CaO)
700 K (800°F) 900 K (1160°F) _ . 1100 K (1520°F)
1.
4.
9.
5.
1.
10 X 105
90 X 10"3
80 X 10-6
86 X 10"5
1.3214
64 X 10~5
»
1.3
--
1.7
--
0.3
2.7
36.17
6.38
57.45
100.00
.107.24
3.015 X 10-4
1.982 X 10-5
1. 763 X 10"5
2. 161 X ID"2
2.015 X 10'4
1 10 100
1.02574 1.225834 1.3
0.27426 0.074166
1.97402 1.77321 1.700
0.00024 0.003014 0.0080
0.0255 0.22282 0.2920
2.9745 2.77718 2.7080
39.6847 37.1258 36.1088
0.0048 0.0631 0.1699
0.5126 4.6652 6.2022
59.7979 58.1459 57.191
8.582 75.278 100.00
. 3.020
5.6 X 10~5
3.336 X 10-
1. 563 X 10-
1.748 X 10-
9.96 X 10"*
1 10
1.002148 1.02112
0.297852 0.27888
1.997804 1.97843
0.000048 0.00045
0.002100 0.2067
2.9979 2.97933
39.9732 39.7364
0.0010 0.0090
0.0420 0.4152
59.9838 59.8394
0.716 7.040
5
5
3
100
1.18835
0.11165
1.8078
0.00385
0.18450
2.8155
37. 5713
0.0800
3.8344
58. 5143
62.783
B-103-1601
-------
TABLE 5. CASE II (0.3 MOLE CaS, 3 MOLES H20, 3 MOLES C02> 1 MOLE CaO) (Continued)
Temperature
Reaction K Values
CaO + CO2 - CaCO3
CaS + ECOZ - CaCOj + COS
CaS + 2COZ - CaCOj +• CO•+ 1/2 Sz
CaS + 2C02 - CaCOj -I- CO + 1 /8 S8
CaS + HZO + COZ - CaCO3 + HZS
CaS + H2O - CaO + H2S
CaS + CO2 - CaO +• CO + 1 /2 Sz
Pressure, atm
Composition, mole
Solid Phase
CaCO3
CaO
CaS
Gas Phase, mole
COZ
COS
H2S
Sz
HZO
CO
Gas-Phase, %
COZ
COS
HZS
Si
HZO
CO
CaS Conversion, %
1300 K (1880°_F)
1.98 X 10'1
4.357 X 10-5
1.165X 10-*
1.2406-X 10-6
7.664 X lO'4
7.36 X 10-3
1.1181 X 10-3
10
48.9388
49.5102
100
—
1.073074
0.0226926
2.948845
0.021919
0.025578
2.978081
0.051155
--
1.045474
0.254526
2.976445
0.021919
0.011778
2.978081
0.023555
1.104462
0.195538
1.876596
0.08552
0.009471
2.914480
0.018942
38.2588
0.3638
0.4245
49.4240
0.8489
0.3646
0.1959
49. 5374
0.3918
1.7435
0.1931
59.4184
0.3862
24.358
15.158
34.821
B-103-1601
-------
Temperature
TABLE 6. CASE III (1 MOLE CaO, 0.3 MOLE CaS, 3 MOLES C02>
700 K (800°F) 900 K (1160T)
Reaction K Value
CaO + COE - CaCO3
CaS + 2CO2 - CaCO3 + COS
CaS + 2CO2 -• CaCO3 + CO + 1 /2S2
CO + 1/2 S2 -COS
Pressure, atm
Composition
Solid Phase, mole
CaCO3
CaS
CaO
Gas Phase, mole
C02
COS
CO
S2
Gas Phase, %
COZ
COS
CO
sz
CaS Conversion, %
Minimum Pressure for 100%
Conversion of CaS, atm
1
1.009714
0.290286
1.980572
0.009714
99.5119
0.4881
3.Z38
1.13 X 105
4.927 X 10'3
9.786 X 10"6
503.6
10 100
1.086016 1.30
0.213984
1.827968 . 1.4
0.086016 0.3
95.5059 82.3529
4.4941 17.6471
28.672 100.00
52.81
107.24
3.0155 X 10--
1.982 X 10"5
15.212
1 10
1.0006 1.01192
0.2994 0.28808
1.9988 1.976164
0.0006 0.011918
99.9700 99.4005
0.0300 0.5995
0.200 3.973
»100
^
100
1.055350
0.24465
1.88930
0.05535
97.1537
2.8463
18.45
B-103-1602
-------
TABLE 6. CASE III (1 MOLE CaO, 0.3 MOLE CaS, 3 MOLES C00) (Continued)
Temperature
1100 K (1520°F)
1300 K (1880°F'
fo
Reaction K Value
CaO + COZ - CaCO3
CaS + ZCO2 - CaCO3 + COS
CaS + 2CO2 - CaCO3 + CO + 1/2S2
CO + 1/2 S, - COS
&
Pressure, atm
Composition
Solid Phase, mole
CaCO3
CaS
CaO
Gas Phase, mole
coz
COS
CO
sz
Gas Phase, %
C02
COS
CO
sz
CaS Conversion, %
Minimum Pressure for 100%
3.049
5.626 X 10-5
3. 3356 X 10~5
1.6867
1 10
1.000113 1.001123
0.299774 0.298877
1.999774 1.997754
0.000113 0.001123
99.9943 99.9438
0.0057 0.0562
0.038 0.370
»>100
o.m
4.357 X :.0"5
1.165 X ,0-4
0.374
100 1 10
1.011066 1.0126
0.288934 0.2595 0.2874
1.0405
1.977868 2.9595 1.9*75
0.011066
0.0405 0.01Z6
0.0202 0.0063
99.4436 97.9902 99.0E80
0.5564
1.3410 0.6473
0.6688 0.3237
3.689 13.5 4.20
»»ioo
100
1.0058
0.2942
1.9884
0.0058
0.0029
99. 5644
0.2904
0.1452
1.93
Conversion of CaS, atm
B-103-1602
-------
TABLE 7. CASE IV
OJ
Temperature
Reaction K Values
CaO + SO2 - CaSO3
CaS +2SO2^ CaSO4 + S2
CaS + 2SO2 -* CaSO4 + 1
CaS + 2SO2 - CaSO4 + 1
CaS + 2SO2 -• CaSO4 + 1
CaS +3/2 SOZ - CaSO3
CaS + 3/2 SO2 -* CaSO4
CaS +3/2 SO2 -* CaSO3
CaS +3/2 SO2
CaO +3/2 SO2
CaS + 1/2 SO2
Pressure, atm
CaSO3
CaSO4
CaO +
12 S4
/3 S6
/4S8
+ 3/4 S2
+ 3/8 S4
+ 1/4 S6
+ 3/16 S8
+ 1/4 S2
3/4 S2
Composition
Solid Phase, mole
CaO
CaS
CaSO4
Gas Phase, mole*
S2
S02
CaS Conversion, %
(0.3 MOLE CaS, 1 MOLE CaO, 3 MOLES S02>
900 K (1160°F)
1.3
0.320266 (24.2640)
0.057574 (4.3614)
0.040295 (3.0528)
0.001787 (0.1354)
.0.9000 (68.1859)
100
Values in parentheses indicate percent.
2. 533 X 10-*
64.021
60.4395
90.4383
55. 5027
8. 5918 X 10-1
7.6865 X lO"1
10.3993 X 10'1
7.2106 X 10'1
2.99 X 10s
0.003395
10
1.3
0.089127 (7.6395)
0.05054 (4.3394)
0.111436 (9.5517)
0.015574 (1.3349)
0.9000 (77.1435)
100
100
1.3
0.019105 (1.729)
0.024518 (2.219)
0.122436 (11.082)
0.038739 (3.5061)
0.9000 (81.463)
100
B-103-1603
-------
TABLE 7.
CASE IV (0.3 MOLE CaS, 1 MOLE CaO, 3 MOLES S02) (Continued)
N>
JS
Temperature
Reaction K Values
CaO + SO2 - CaSO3
CaS +2SO2- CaSO4 + S2
CaS + 2SO2 - CaSO4 + 1 /2 S4
CaS + 2SO2 - CaSO4 + 1 /3 S6
CaS + 2SO2 - CaSO4 + 1 /4 S8
CaS +3/2 SO2 - CaSO3 + 3/4 S2
CaS -t- 3/2 SOZ -* CaSO4 + 3/8 S4
CaS +3/2 SO2 - CaSO3 + 1 /4 S6
CaS +3/2 SO2 -* CaSO3 + 3/16 S8
1100 K (1520°F)
CaO +3/2 SO2
CaS + 1/2 SOZ
Pressure, atm
CaSO4 + 1 /4 S2
CaO + 3/4 S2
Composition
Solid Phase, mole
CaO
CaS
CaSO4
Gas Phase, mole*
S2
S4
S6
S8
S02
CaS Conversion, %
0.0225
1.2775
0.27505 (22.4893)
0.002925 (0.2392)
0.00005 (0.0041)
0.9450 (77.2674)
100
"* Values in parentheses indicate percent.
15.28316
0.36134
0.07903
0.05384
0.02627
0.04526
0.014477
0.010855
0.006337
122.0
0.00296
10
100
1.3
0.2440 (20.8418)
0.02425 (2.0714)
0.002475 (0.2114)
0.90 (76.8754)
100
1.3
0.1110 (10.1742)
0.051 (4.6746)
0.029 (2.6581)
0.90 (82.4931)
100
B -10 3 -1 60 3
-------
NJ
Ui
TABLE 7.
Temperatur e
CASE IV (0.3 MOLE CaS, I MOLE CaO, 3 MOLES S02> (Continued)
Reaction K "Values
CaO + SO2 - CaSO3
CaS +2SO2- CaSO4 -I- S2
CaS + 2SO2 - CaSO4 + 1 /2 S4
CaS + 2SO2 -> CaSO4 * 1 /3 S6
CaS + 2SO2 - CaSO4 + 1/4 S8
CaS + 3/2 SO2 - CaSO3 + 3/4 S2
CaS + 3/2 SO2 - CaSO4 + 3/8 S4
CaS +3/2 SO2 -» CaSO3 + 1/4 S6
CaS + 3/2 SO2 - CaSO3 + 3/16 S8
CaO + 3/2 SO2 -> CaSO4 + 1 /4 S2
CaS + 1 /2 SO2 - CaO + 3/4 S2
Pressure, atm
Composition
Solid Phase, mole
CaO
CaS
CaSO4
Gas Phase, mole*
S2
0.30
1.0
1300 K (1800°F)
0.52234
0.027907
0.002486
0.000931
0.000398
0.01666
0.002717
0.00130
0.000688
0.87496
0.03189
10
0.3
1.0
100
1.3
0.25(14.2857) 0.25(13.2857) 0.55(37.9310)
SO2
CaS Conversion, %
1.5(85.7143) 1.5(85.7143) 0.9(62.0690)
0.0 0.0 100.0
Values in parentheses indicate percent.
B-103-1603
-------
TABLE 8. CASE V (0.3 MOLE CaS, 1 MOLE CaO, 1 MOLE 0 )
Temperature 700 K (800°F) 900 K(1160°F) 1100 K(1520°F) 1300 K(1880°F)
Reaction K Values
CaS 4- 2O2 -* CaSO4 e51-82 e36'2 e26-31 e19'91
CaS + 1/2O2 - CaO+ 1/2S2 4.45X106 1.35X105 1.44X104 7.425X103
CaS -I- 3/202 - CaS03 e38-6o e"'73 e18'72 e14'32
Pressure, atm 1 10 100 1 10 100 1 10 100 1 10 100
Composition
Solid Phase, mole
0.225 0.225 0.
10 i.oo i.oo i.oo
0.075 0.075 0.075 0.075
CaSO3
Gas Phase, mole
O2 0 0 0 0
Conclusion: The only reaction of importance is CaS + 2O2 -» CaSO4. A-u-129
-------
N)
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00
c
II
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oo
n
fu
0)
I
o
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o
o
o
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ffl
Ni
o
co
VI
CO
rt
§
H2S IN THE GAS PHASE,%
S- 5o
u>
(O
%'Q3iy3ANOO SOD
-------
COS IN THE GAS PHASE,%
NJ
CO
OQ
i-i
fD
VO
n
HI
o
o
05
CO
I
r>
o
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%'a3ia3ANOD SOD
-------
EQUIPMENT
PILOT UNIT
An existing pilot-development unit was renovated for use in the project.
The unit is 10 inches in diameter and about 15 feet tall. A 6-inch pipe,
6 feet in length, was used as an inside overflow tube, so that the fluidized-
bed section is 6 feet in height. The bottom was redesigned with a distributor
plate that has nonweep nozzles. Figures 10 through 16 show the reactor config-
uration and design in addition to nozzle operating characteristics.
Material is screw-fed into the bottom of the reactor by a variable speed
drive. Fluidizing gas (usually hydrogen) is introduced below the distribution
plate, flows up through the nozzles, and fluidizes the material in the bed.
When the material reaches the 6-foot level, it overflows the center pipe and
falls into one of the receivers, as determined by the position of the diverter
valve on the overflow line.
The bed is heated by external electric heaters. Six heating zones are
controlled by, temperature controllers. The gas flows out the top of the
reactor, through a cyclone, a scrubber, and a knockout drum, and then out the
stack. After the first runs, the cyclone was removed because tars were con-
densing in the unit. The dust loading was small and could be handled by the
wet scrubber.
BATCH REACTOR
To gather background data while the pilot unit was being renovated, a
batch reactor was set up. A flow diagram is shown in Figure 17. The reactor
(shown schematically in Figure 17) is a 1-1/2 inch stainless-steel pipe with
a sintered disk plate for fluidization. The reactor sits in a fluidized,
heated sand bed. Preheated air fluidizes the sand. Nitrogen or hydrogen was
used to fluidize the material charged to the reactor, with a rotameter for
flow indication. A bubbler was used to condense tars and to trap solid parti-
cles before the gas was exhausted.
THERMOBALANCE
The thermobalance is a laboratory device that continuously measures the
weight of a sample as it is being exposed to a controlled environment of
temperature, pressure, and surrounding gas composition. It has a heated zone
into which the sample can be lowered and then heated with a controlled time-
temperature profile. If desired, rapid heat-up can be effected by preheating
the unit to the desired temperature and then lowering the basket into the hot
zone. Gas flow is large relative to the coal sample size so that large changes
29
-------
WATER
CYCLONE
(Later Removed
From System)
\
HEATERS
DISTRIBUTION
PLATE
AIR —flB»
i
VENTURI
SCRUBBER
FINES
TAR'
AND
WATER
TREATED
COAL
REC
-OVERFLOW
FEED
HOPPER
SCREW
FEEDER
INSIDE
SLEEVE
DIVERTER
VALVE
TREATED
COAL
REC
TO
STACK
A7707I723
Figure 10. Reactor flow sheet.
30
-------
.SLEEVE 6-in.
l/8-in.PIPI
NIPPLE!
E
S
— •»
-1
• —
h
^x
r
L
N
f]
^
\
h
-
II
^ —
^^fc__ j
1
f
\
^^
x
_
, —
^^
x^
PIPE
REACTOR SHELL
NOMINAL 10-in.
<*^~ SCHEDULE 60
PIPE
.._ cetrn CPDIT\A/ H'
rttU bLKLW ȣ_
T |_ STANDARD 10-in.,
1 1 1 U--^i50-psi FLANGE
I ^Xl/4-in. DISTRIBUTION
PLATE
mm
A- 14 -45
Figure 11. Distribution plate detail.
31
-------
2m-
THREE HOLES FOR
l/4-in. PIPE
COUPLING WELDED
IN
l/4-in. PIPE COUPLING
AT 3 HOLES, WELDED ON
TWELVE I-in. HOLES
EQUALLY SPACED
6 HOLES EQUALLY SPACED,
DRILLED TO PASS 1/8-in.
NOMINAL PIPE, DRILL
SIZE 7/16-in.
COLLAR 5-3/4in. OD
x I in. TALL x l/4-in. THICK
-3-15/32 in.
ALL CONSTRUCTION
304 STAINLESS
JT
T
l/4-in.
l/8-in. HALF COUPLING
AT 6 HOLES, WELDED ON
D-14-48
Figure 12. Distributor plate.
32
-------
10-GAUGE
PLATE WELDED
TO PIPE
3/4-in. 304 STAINLESS-
STEEL PIPE
SCHEDULE 80
2-1/16 in. HOLES
— l/8-in, HALF-COUPLING
A-14-49
Figure 13. Distributor nozzles.
33
-------
o>
X
O.Ol
O.lO h
0.10
1.0
FLOW, SCF/min
10
A-II2-999
Figure 14. Flow of H~ in distributor nozzle.
34
-------
O.I
0.4
0.6 0.8 1.0 2
VELOCITY, ft/s
A-II2-IOOO
Figure 15. Distributor plate nozzle pressure drop versus reactor gas velocity.
35
-------
12 in.
J_
FRONT VIEW
MATERIAL
304 SS [EXCEPT AS NOTED]
3- in. NIPPLES
TWO 3-in.SCH 40 NIP'S, I END N.P.T.;
ONE WITH 1/4 -in. HALF-COUPLING
VALVE
HILLS-McCANNA TOP ENTRY 300 psi
SCREWED END, GRAPHITE SEAT,
3-in. BALL VALVE
LIFTING PLATE
2 in. x 2 in. x 3/8 in. ft. WITH l/2-in.
HOLE O.C. IN-LINE (VERTICALLY)
WITH LEG [MILD STEEL]
HEADS
TWO 20-in. 0 O.I5-in.-THICK DISH HEADS
WITH FLANGES WELDED ON }
ONE WITH l/2-in. HALF-COUPLING
RINGS
THREE l/2-in.<|> BAR
SHELL
20-in.
SCH 5 PIPE, 30 in. LONG
FLANGES
ONE 3-in.,l50-psi R.F. BLIND FLANGE
ONE 3-in.,l50-psi SLIP-ON FLANGE
TWO 6-in.,l50-psi SLIP-ON FLANGE
WITH BOLTS WELDED AS STUDS;
ONE 6-in.,l50-psi R.F. BLIND FLANGE
ONE 6-in,l50-psi R.F. FLANGE WITH
HOLE FOR 3-in. PIPE
LEGS
THREE 2 in. x 2 in. x 1/4 in. ANGLE AND
3-3/4 in. x 4-5/8 in. x 1/4 in. THICK BASEPLATE
FOR WHEELS WITH FOUR 3/8-in.$ HOLES
2-3/4 in. x 3-5/8 in. O.C. (MOUNT LEGS
120° APART) [MILD STEEL]
WHEELS
THREE 5Hn.0 SWIVEL CASTERS WITH
BRAKES
SHACKLE
3/8-in. SCREW PIN ANCHOR SHACKLE
[FORGED STEEL]
0-14-47
Figure 16. Treated coal receiver.
36
-------
N
-CXJ
CONTROL
VALVE
SHUTOFF
VALVES
AIR
ROTAMETER'
T/C
AIR
PREHEATER
5
A
?
8
FLUID-
IZED
SAND
4T/C
TO
FUME
ELIMI-
NATOR
WET
TEST
METER
BUBBLER
24 pt
TR
A-II2-IOOI
Figure 17. Batch coal desulfurization equipment.
37
-------
in coal composition are associated with very little change in gas qualities.
A flow sheet for the thermobalance test station is shown in Figure 18.
MODIFIED BATCH REACTOR
The batch reactor used in the first phase of the program was not as
flexible in operation as desired. For this reason, a new reactor and heating
unit was constructed.
A diagram of the new type of reactor is presented in Figure 19. With
this type of reactor, material charging and discharging was simplified. The
external heater was designed so that the elements heat the reactor directly.
The elimination of the sand bed reduced the system mass; heat-up was faster
and internal reactor temperatures were easier to control. A flow sheet for
the new system is presented in Figure 20.
38
-------
GAS
SAMPLING
H2
N2
THERMO-
BALANCE
OJ
vo
VENT
GAS
SAMPLING
COOLING
H20
GAS
COOLER
A75I229I8
Figure 18. Flow diagram of thermobalance system.
-------
l-l/2-in. PIPE
CAPS
•
1
•H^
•^^V
i
^^m
^•H
i
^^^•fl
h
^^^^^^^•VHHIPV
••^^•••••••••I^MI
\
\
\
\
1 1
}
\
1
^•••••••••1
•H^M^^MM
i
1 1
—
-«
NOTE
TUC
THERMOCOUPLES
l-l/2-in. UNION
l-l/2-in SEAMLESS
PIPE
DISTRIBUTION
PLATE
NOTE: ALL CONSTRUCTION
316 SS
THERMOCOUPLE
A-73-1048
Figure 19. Modified batch reactor.
40
-------
AIR-
N2-
H2 -
-OO-
-txj-
•OO-
HIGH AND
LOW FLOW
ROTAMETERS
f
3T/C
3T/C
TEMPERATURE
RECORDER
IT/C
TEMP.
CONT.
SCR
I IT/C
TEMP.
CONT.
II
220-V POWER
II
SCR
'GAS
> SAMPLE
0
N
E
I
I I
Zl
8j
2!
EXHAUST
WATER
QUENCH
A75I229I7
Figure 20. Modified batch reactor flow system.
-------
LABORATORY PROCEDURES
Initially, samples were analyzed by standard ASTM methods. The coal-
lime mixture was separated by a float-sink process in carbon tetrachloride,
and each fraction was analyzed.
Total sulfur was determined by combusting the sample with a flux of
magnesium oxide and sodium carbonate (Eschka reagent). The S02 generated was
collected by the flux and, after dissolution, was precipitated as barium
sulfate. The total sulfur content was then determined gravimetrically. A
second sample was used to determine the sulfur by types. It was treated with
HC1, and the H2S evolved was precipitated as cadmium sulfide. This I^S is
assumed to correspond to the sulfide content of the sample. The liquid from
the HC1 treatment contained dissolved sulfate, which was precipitated with
barium. The pyritic sulfur was not attacked by HC1 in the first leach, but
all the nonpyritic iron was removed. To determine the pyrite content, the
sulfur was digested with concentrated nitric acid for 4 hours and the iron
content determined titrametrically. In the standard technique, this iron is
assumed to correspond to the pyrite content of the sample. The organic sulfur
content was then determined by subtracting the sum of the other sulfur types
from the previously determined total.
This analytical procedure is a lengthy process and is subject to sampling
errors. Several other sources of error were also found:
a. The float-sink separation in carbon tetrachloride caused iron pyrite
and iron sulfide (properly associated with the coal) to partially
distribute in the lime fraction.
b. Treated residue samples cannot be ground without significant loss of
calcium sulfide (caused by hydrolysis with atmospheric moisture).
c. Analyses of lime-pyrite mixtures resulted in apparently low pyritic
sulfur determinations. Possibly the nitric acid digestion was
insufficient for complete removal of this material.
d. Calcium sulfate formation from lime in the residue was possible during
the combustion for total sulfur analysis. Any calcium sulfate formed
would not be dissolved in the standard water dissolution of the flux.
These factors and others suggest that the standard ASTM procedures should be
modified for this work.
Development of a new analytical procedure was undertaken, with emphasis
on several improvements. Among these were quicker analysis, use of one sample
for all work, and reproducibility. The following procedure resulted.
42
-------
About 4 to 5 grams of the unground sample is treated in a flask with 6N
HC1. The l^S evolved flows through three cadmium carbonate traps and is pre-
cipitated as cadmium sulfide. This is further treated with HC1 and iodine.
Sulfide (S=) is determined titrametrically.
The treated residue is filtered, giving a filtrate containing sulfate
(S0^~), nonpyritic iron, and calcium (Ca"*"1"). The residue is air-dried, ground
in a diamonite mortar, and reextracted under reflux with 6N HC1. This second
extraction removes additional small amounts of the S0.= and nonpyritic iron.
The two filtrates are combined and analyzed. The iron is precipitated from
the solution as ferric hydroxide, then dissolved and analyzed colorimetrically.
The filtrate, containing S0^=, is acidified, boiled, and barium sulfate pre-
cipitated by the addition of barium chloride. The precipitate is filtered,
dried, and weighed. This gives a measure of the acid-soluble sulfate. The
filtrate is also analyzed for Ca"*""1" by atomic absorption.
After the second HC1 extraction, the residue is air dried, intimately
mixed with Eschka reagent, and fired at 800°C for several hours. The result-
ing mixture contains S0»~ from pyritic and organic sulfur; this sulfate is
readily extracted in hot water. The iron originally present as pyrite appears
as iron oxide (Fe^O.,). _The Eschka-water mixture is filtered to separate a
solution containing SO/" from the MgO-Fe_0- residue. The filtrate is acidified
and boiled; then barium chloride is added to precipitate the S0,=. Digestion
followed by filtration and drying gives a measure of both pyritic plus organic
sulfur. Pyritic sulfur is calculated from the iron in the Eschka residue.
Organic sulfur is determined by the difference of [organic plus pyritic sulfur]
minus pyritic sulfur, as calculated by the iron analysis.
Several chemicals were tested by this procedure. Reagent-grade zinc
sulfide gave 96% to 98% recovery of theoretical S~. Technical-grade calcium
sulfide, specified as 80% to 85% CaS, gave 80% recovery of S=, which is good
agreement. A sample of pure iron pyrite was analyzed. Ninety-nine percent
of the theoretical iron and 96.4% of the theoretical sulfur were obtained.
Technical-grade iron sulfide gave 93.7% of the theoretical sulfide. NBS-
certified coal (3.02±0.008% sulfur) gave 99.55% of theoretical sulfur by
Eschka.
Figure 21 presents the revised analytical procedure, which was used to
analyze samples from later tests.
43
-------
Coal/Lime Sample
(ung round)
6N HC1
HZS GAS
I HC1 extract |
II
Residue
Air-dry, grind
Reextract in HC1
I I
Residue
Pyrites, Organic S
Collect in CdClz,
Na2CO,, and HC1.
Analyze by iodimetry.
Soluble SO4 , Fe,
Br2, boil
I
Soluble SO4~, Fe, Ca4
r
Air -dry
MgO-Na2CO3 fusion
H2O leaching
1
n i
Residue
Fe203, MgO
Silicates
1
d
LHC
1 1
Silicates
Tl
iLl
1
Fe+++
Leachings
S04=
a) Br2,
HC1, boil
b) Adjust pH
c) BaCl2
II
A i T, BaSO4
Analyze by *
Colorimetric (measure
method
(measure of
pyritic S
,
1
Waste
, solutior
of
pyritic +
organic S)
II
Fe(OH)3
(additional
Br2, boil
NH4OH
|
1 ..
SO4 , Ca4"1"
nonpyritic Fe)
| HC1 |
Analyze by
Adjust pH
Bad;,
1, _ ,.,,
i e(C
(nonpyr
[»
)ti)3 £>U4 , ^
£° * e) Adjust
5l| BaCl2
| 1
1
Fe Solution BaSO4
a
PH|
1
^_f
Ca
Analyze by (measure_of Analyze
/-• 1 «^^ A » O -1C, Cf\ "~\ V - —A.— i —
Coloriixietric o
-------
TEST RUNS - START OF PHASE I
BATCH REACTOR
As previously noted, the batch reactor was used to gather preliminary
data concerning the process while the pilot unit was being renovated for use
in this program. A 100-gram charge was used in all the preliminary batch
tests. The first tests used a mix of 4 parts coal to 1 part lime by weight.
The coal used in these tests was the initial coal from the Illinois No. 6 seam.
This ratio corresponds to about 400% of the stoichiometric lime requirement
if the coal contains 4% sulfur. Laboratory analysis indicated that the lime
was hydrating (from coal moisture) and carbonating before it could react with
HpS to give CaS. Therefore, the ratio was changed to 2 parts coal and 1 part
lime for Run 14 and all subsequent tests. In one test, iron pyrite and
calcium oxide were used as a mixture to prove the acceptor concept without
interference from other coal-related effects.
In running a test, 100 grams of material was charged to the reactor,
which was then lowered into the fluidized sand bed. All heaters were turned
on, and the reactor was brought to the desired temperature with nitrogen
fluidizing the sample. When the reactor temperature was reached, hydrogen
was introduced for a specified time (1/2 hour, 1 hour). For base-line com-
parisons, similar runs were made using only nitrogen. The temperature ranged
from 600° to 1000°F in 100°F increments.
After the specified time at temperature, the reactor was removed from
the sand bed. If hydrogen had been used in the test, the system was purged
with nitrogen. When the reactor was cool, it was opened, and the sample was
removed and submitted to the laboratory for analysis.
PILOT-UNIT TESTS
Pilot-unit tests were started when the modification of the pilot unit was
completed. Coal alone was used in the first six tests to determine its oper-
ating and fluidization characteristics. After these tests, a 2 to 1 mixture
of coal and lime in the selected screen size was used for feed. The initial
Illinois No. 6 coal was used in these tests.
Feed material was mixed and charged to the feed hopper before the run
was started. The heaters were turned on, and the controllers were set for the
tun temperature. The gas flow was set to meet the required bed velocity for
fluidization. The feed screw was turned on and the speed adjusted to provide
the coal feed rate selected. The diverter valve, at the reactor discharge,
was set so that discharged material went into the waste-material receiver.
After the reactor bed was filled and the system was in steady-state operation,
the diverter gate was switched, so that the discharged material went to the
second receiver to ensure a good sample.
45
-------
When enough sample was obtained, the diverter gate was switched back to
the waste-material receiver. If the desired run was complete, the unit was
purged with nitrogen and shut down. If other conditions were to be checked,
the controls were changed and the receiver with the good sample exchanged for
an empty. When the new conditions were met and the system was at steady-state,
the diverter was again switched to obtain a sample at the new conditions.
Several points can be checked with this technique, and only one heat-up and
one cleanout are necessary. Feed rate and final temperatures were the primary
parameters varied for the pilot tests. Samples from all tests were submitted
to the analytical laboratory.
TEST RESULTS - BATCH UNIT
Batch tests were run with the feed types presented above except for Run 20,
in which FeS2 and CaO were used to test the getter concept. The test results
and conditions are listed in Tables 9 through 12. The missing run numbers
correspond to tests that were terminated early because of operational problems
such as off-gas plugs, burned out heater elements, and controller malfunction.
Table 9 shows the data for the float (treated coal) portions of these
tests. The results are presented in ascending temperatures for comparison
purposes. Base runs were made with nitrogen to determine the effects of only
heat on sulfur removal. In each set, the hydrogen shows better removal than
nitrogen except at 700°F. No tests, however, show enough sulfur removal to
yield an acceptable product, even at 1000°F and a ratio of 2 parts coal to
1 part lime. Problems with material separation prevented complete analysis of
Runs 18 and 19.
Data for the sink portions of the tests are shown in Table 10. The high
sulfide content of the separated sink fraction shows that pyrite reduction is
being made. The sulfate content is caused by heavier, mineral elements of the
coal reporting to the sink when separated. Part of the coal fraction (or coal
tars adsorbed in the lime) also shows up in the sink portion, as evidenced by
the carbon values.
Batch test Run 20 (Table 11) was made with FeS, instead of coal to
determine the reduction of pyrite to sulfide-type sulfur. The results show
that most of the FeS2 was converted by FeS and CaS, as evidenced by the sulfide
content and by the increase in nonpyritic iron in the treated sample. Some
sulfur was lost during grinding; this was mostly caused by reaction of CaS
with atmospheric water vapor, as can be determined by examining the results of
the ground and unground samples.
Table 12 lists the analysis of gas samples taken during some batch test
runs. Because only grab samples could be taken from a continuously-variable,
batch situation, the analyses are not definitive, but give a representation of
the distribution of the gas species. Evolution of H2S is increased at higher
temperatures. The longer-chain molecules containing sulfur are derived from
the thermal decomposition of the coal, as are the carbon-bearing gases in the
mass spectrometer analysis.
46
-------
TABLE 9. FLOAT PORTION OF BATCH TESTS
Run No.
Temp, °F
Duration, min
Treatment Gas
Sample
Lab. Ident. No.
Sample Weight, g
Separated Fraction
Weight recovered, g
Proximate Analysis, wt $
Moisture
Ash
Volatile Matter
Fixed Carbon
Ultimate Analysis, wt %
Ash (total dry)
Acid Insoluble
Calcium
Carbon
Hydrogen
Sulfur
Sulfide
Sulfate
Pyritic
Organic
Oxygen (by difference)
Nitrogen
Carbon Dioxide
S as SO2
Raw
Coal
4.5-5.2
10.4-11.0
34. 7-35.4
49. 1-49. 7
10.88-11. 60
6. 71-68.4
4. 66-4. 70
3.05-3.23
11.76-12. 14
1.23-1.25
6. 10-6.46
Heating Value, (S free),Btu/lb 12276
SO2/106 Btu
Type Mix (original)
Ratio by Weight
5.12
10 X 80 M.H.
Coal Lime
20907
3.
9.!
36.
51.
10.
69.
4.
2.
0.
0.
1.
11.
1.
5.
72 0.0
3 89.8
1
38
20 89.81
1.90
66.41
32 0.55
72 1.25
62 0.08
47
64
51
89 7.64
21 0.01
0.66
24
12481
4.
20
1
600
30
H2
Reac
Prod
20654
39.54
Float
30.13
0.9
7.6
34. 7
56.8
7.66
72.2
4.76
1.87
0.0
0.07
0.42
1.38
12.36
1.15
3.74
12920
2.89
Coal/
Lime
4/1
5
600
30
N2
Reac
Prod
20657
46.7
Float
36.06
1.2
8.6
35.8
54. 4
8. 72
71.4
4. 72
2. 49
tr
0. 12
0.46
1.91
11. 50
1.17
4.98
12783
3. 90
Coal/
Lime
4/1
2
700
30
H2
Reac
Prod
20655
49.19
Float
32.01
0. 4
8.2
33.1
58.3
8.20
72. 5
4. 59
2.26
0.02
0. 11
0.24
1.89
11. 18
1.29
4. 52
12875
3.51
Coal/
Lime
4/1
9
700
30
N2
Reac
Prod
20679
56.00
Float
46.7
3.07
9.9
10.21
49.96
9. 75
70. 56
4.84
2.09
0. 14
0. 59
1.36
10.86
1.20
0.24
4.18
12723
3.29
Coal/
Lime
4/1
3
800
30
H2
Reac
Prod
20656
43.36
Float
33.00
0. 7
9.4
24.9
65.0
9. 43
74.0
4. 14
1.90
0.07
0.07
0. 14
1.12
9.27
1.26
3.80
12860
2.95
Coal/
Lime
4/1
10
800
30
N2
Reac
Prod
20680
56. 55
Float
46.2
0. 9
8. 7
8.83
67.7
73. 42
3.99
2.32
0.02
0.07
0. 52
1.71
9.69
1.35
0.40
4. 64
12699
3.65
Coal/
Lime
4/1
14
800
30
H2
Reac
Prod
21156
60. 50
Float
33.85
0.3
9.0
20.2
70. 5
9.03
66.39
5.30
74.94
3. 60
1.99
0. 10
0. 10
0.14
1.65
8.78
1. 44
0.22
3.98
12718
3.13
Coal/
Lime
2/1
B-14-113
-------
TABLE 9. FLOAT PORTION OF BATCH TESTS (Continued)
oo
Run No.
Temp, °F
Duration, min
Treatment Gas
Sample
Lab. Ident. No.
Sample Weight, g
Separated Fraction
Weight recovered, g
Proximate Analysis, wt ^
Moisture
Ash
Volatile Matter
Fixed Carbon
Ultimate Analysis, wt %
Ash (total dry)
Acid Insoluble
Calcium
Carbon
Hydrogen
Sulfur
Sulfide
Sulfate
Pyritic
Organic
Oxygen (by difference)
Nitrogen
Carbon Dioxide
S as SO2
Heating Value, (S free),Btu/lb
SO2/106 Btu
Type Mix (original)
Ratio by Weight
12
800
60
N2
Reac
Prod
20736
57. 3
Float
47. 6
0.7
8.4
8.46
65.3
73.50
4.23
2.31
0.01
0. 10
0. 57
1.63
9.84
1.37
0.29
4.62
12834
3.60
Coal/
Lime
4/1
16
1000
30
H2
Reac
Prod
21429
54. 7
Float
30. 6
0. 8
11.4
15.4
72.8
11.47
75.22
3.00
1.67
0. 11
0.08
0.06
1.42
6.65
1.32
0. 67
3.34
12450
2. 68
Coal/
Lime
2/1
18
900
30
H2
Reac
Prod
21743
Float
1.4
9. 1
21.9
67.6
9. 18
74.95
3.88
0.11
0. 22
1.35
Coal/
Lirne
2/1
19
900
30
H2
Reac
Prod
21745
Float
1.2
13.8
13. 7
71.3
14.01
74.24
2.69
1.03
Pretreated
Coal/ Lime
2/1
B-14-113
-------
TABLE 10. SINK PORTION OF BATCH TESTS
vo
Run No.
Temp, *F
Duration,min
Treatment Gas
Lab Ident. No.
Sample Weight, g M. H. Lime
Separated Fraction
Weight Recovered, g
Proximate Analysis, wt 4
Moisture 0.0
Ash 89.81
Ultimate Analysis, wt £
Ash (total dry) 89.81
Acid Insoluble 1,90
Calcium 66.41
Carbon 0.55
Hydrogen 1.25
Sulfur 0.08
Sulfide
SuUate
Pyritic
Organic
Oxygen (by difference) 7. 64
Nitrogen 0.01
Carbon Dioxide 0. 66
Type Mix (original)
Ratio by Weight
1
600
30
Hj
20654
39.54
Sink
4.16
0.2
2.52
0.59
0.22
0.31
0.05
0.01
Coal/
Lime
4/1
5
600
30
NZ
20657
46.7
Sink
8.50
3.4
2.49
0.68
0. 16
0.14
0.06
0.32
0. 5
Coal/
Lime
4/1
2
700
30
Hz
20655
49.19
Sink
8.07
0.1
8.49
2.18
1.62
0.27
0.50
0.42
0.43
Coal/
Lime
4/1
9
700
30
Nz
20679
WHVHMHV^V
56.00
• Sink
8.64
0.39
75.36
75.66
4.44
45.5
3.58
2.31
1.42
0.15
0.43
0.46
0.38
14.89
0.06
2.07
Coal/
Lime
4/1
3
800
30
Hz
20656
43.36
Sink
8.44
0.1
12.4
1.96
1.19
0.39
0.48
0.33
0.0
0.2
Coal/
Lime
4/1
10
800
30
NZ
20680
56.55
Sink
10.35
0.3
73.3
73.49
9.00
10.65
1.86
2.70
0.15
0.59
1.96
0.0
8.47
0.18
2.65
Coal/
Lime
4/1
14
800
30
HZ
21156
^^v^^M^*^
60.50
Sink
26.65
0.0
85.3
85.3
3.91
62.4
5.80
0.68
2.03
1.01
0.92
0.09
0.01
2.30
0.10
3.79
Coal/
Lime
2/1
B. 14-112
-------
TABLE 10. SINK PORTION OF BATCH TESTS (Continued)
Ui
o
Run No.
Temp, °F
Duration,min
Treatment Gas
Lab Ident. No.
Sample Weight, g
Separated Fraction
Weight Recovered, g
Proximate Analysis, wt *
Moisture
Ash
Ultimate Analysis, wt $
Ash (total dry)
Acid Insoluble
Calcium
Carbon
Hydrogen
Sulfur
Sulfide
Sulfate
Pyritic
Organic
Oxygen (by difference)
Nitrogen
Carbon Dioxide
Type Mix (original)
Ratio by Weight
12
800
60
N2
20736
57. 3
Sink
9.7
0.22
71.4
71. 54
12. 74
12.14
1.79
2.90
0.35
0.76
1.73
0.06
8.41
0. 23
2.99
Coal/
Lime
4/1
16
1000
30
H2
21430
54.7
Sink
24. 1
0. 5
82.9
83. 32
1. 60
1.14
0.99
0.30
0. 55
0.09
0.05
10.65
0.06
2.24
Coal/
Lime
2/1
18
900
30
H2
21774
Sink
0.0
86.0
86.07
6.95
1.36
0.09
Coal/
Lime
2/1
19
900
30
H2
21746
Sink
0.0
93.0
93.2
3. 54
0.43
0.01
Pretreated
Coal/Lime
2/1
B-14-112
-------
TABLE 11. BATCH TEST RUN 20
Feed Unground Ground
Reactor Material
Lab Ident.No.
Separated Fraction
Proximate Analysis,
Moisture
Volatile Matter
Ash
Ultimate Analysis, wt
Ash (Dry)
Carbon
Hydrogen
Sulfur
Sulfides
Pyrite s
Oxygen
Nitrogen
Carbon Dioxide
Iron (Nonpyritic)
21227
Total
0.0
0.0
81. 72
81.72
0.0
0.1
6. 78
0.05
5.28
10.77
0.01
0.62
0.65
21227
Total
0.0
89.5
89. 56
0.26
0. 12
5.23
5.17
0.46
4.34
0.05
0.44
4.88
2122?
Total
0.0
85.83
85.83
0.05
0.07
5.06
4.34
0.16
8.43
0.02
0.54
5.13
21327
Sink
0.3
87.6
87.75
0.05
0.10
4.18
3.22
0.17
7.36
0.01
0.55
4.18
21227
Float
0.2
84.0
84.22
0.18
0.37
3.04
2.15
0.06
11.38
0.01
0.80
3.04
A-14-130
TABLE 12. BATCH TEST GAS SAMPLE ANALYSIS
Run No.
Temperature, °F
Chromatograph, ppm, vol
Hydrogen Sulfj.de
Carbonyl Sulfide
Ethyl Mercaptan
Dimethyl Disulfide
t^Amyl Mercaptan
Methylethyl Disulfide
Methyl Mercaptan
Thiophene
Cf, or Higher
Mass Spectrometer, mol $
Nitrogen
Oxygen
Hydrogen
Argon
Carbon Dioxide
Methane
Ethane
Propane
n- Butane
Ethylene
Propylene
14
800
25.3
6.8
67.6
0.3
18
900
19
900
0.02
0.13
0.03
0.01
0.02
0.01
0.01
0.16
20
900
15.0
0.7
11.9
0.3
0.2
1. 1
--
--
15.2
1.9
6.3
0. 7
10. 5
--
1.3
2.4
28.5
18.6
0. 5
2.2
0.4
1.0
--
--
0.7
__
63.0
0.9
3.4
--
--
--
--
--
__
16.3 16.7 24.0
83.5 83.1 76.0
0.04
A-14-131
51
-------
TEST RESULTS - PILOT UNIT
The pilot-unit run conditions are listed in Table 13. The first six
tests were made with coal (no lime) to check the fluidization, gas rates,
devolatilization, and general operation at design conditions. It was found
that the coal should be screened at —10+80 mesh. The maximum top size was
selected to promote good fluidization, and the bottom size was selected to
minimize the fines in the exhaust system. The gas velocity required was about
3.0 ft/s for satisfactory mixing and operation. Data from these runs and the
time-temperature matrix are presented in Tables 14 through 25.
For Runs 7 through 14, the feed mixture was 2 parts coal (—10+80 mesh) to
1 part lime (—20+60 mesh). In Run 15 the same weight ratio was used, but the
feed material size was all —80 mesh screen. Hydrogen was the fluidizing gas
in all tests except No. 14; in this test, an attempt was made to add steam
to the unit. This attempt was unsuccessful because the wet steam caused a
large pressure drop across the distributor plates and the run was aborted.
No further attempts to use steam were made because a change in the reactor con-
figuration would be necessary.
In Runs 7 through 9C, material was fed to the unit at 50 Ib/hr resulting
in a reactor residence time of about 1 hour. The bed temperatures tested
ranged from 750° to 1000°F in 50°F increments. The feed rate was 100 Ib/hr in
Runs 10 and 11, and the temperatures were 1000° and 900°F. Runs 12A and 13
were made at 25 Ib/hr and 1100° and 900°F. Run 12B was at 200 Ib/hr and 900°F.
The final run with the fine material was made at 60 Ib/hr and 900°F. The time-
temperature matrix for the pilot-unit runs is presented in Table 19. Lab
analyses for Runs 7 through 9C are shown in Tables 20 through 25.
Run 7 (Tables 20 and 21) illustrates the reduction of the pyritic sulfur
in the coal at 1000°F. Sulfide-type sulfur has increased, evidence that the
FeS2 is being converted to FeS and CaS is being formed. In the float-sink
separation, much of the sulfide-type sulfur is reporting to the sink portion.
Some of the coal, or possibly tars absorbed by the lime, is in the sink fraction,
causing the high carbon content. Also, some lime stayed with the float, as
shown by the higher ash content of the float material as compared with the
original coal.
Table 22 shows the analysis for Run 8A. This run is similar to Run 7 but
the temperature was 100°F lower. The results are much the same for both runs;
although the pyritic sulfur has been attacked, the organic sulfur content has
not changed appreciably, therefore, the overall sulfur content is still high.
Run 8B (Table 23) was made at still a lower temperature, 750°F. The
sulfur reduction was even less than in the previous runs. Pyritic sulfur was
not reduced as much as in the other tests so more sulfur remains in the
treated material.
Pilot runs 9A and 9B (Table 24) were made at 950° and 850°F, respectively.
These data also show pyrite-sulfur reduction but the organic sulfur content of
the coal is relatively unchanged. Again, this causes residual sulfur values
that are higher than the desired values.
52
-------
TABLE 13. PILOT-UNIT RUN CONDITIONS
Run No. Feed Rate Tb/hr Temperature, "F Gas
Material
1
2
3
4
5
6
7
8A
8B
9A
9B
9C
10
11
12A
12B
13
14
15
33
63.5
33. 6
66.7
77.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
100.0
100.0
25.0
200.0
25.0
50.0
60.0
Ambient
Ambient
600
800
825
850
1000
900
750
950
850
800
1000
900
1100
900
900
900
900
N2 Raw coal
N2 10 X 80 mesh Coal
N2
N2
N2
H2 \
i 10 X
HZ t,20X
H2
H2
H2
H2
H2
H2
H2
H2
H2
H2
H2 '
80 mesh Coal
60 mesh Lime
I Steam 1 —80 mesh Coal
80 mesh Lime
53
-------
TABLE 14. SIZE ANALYSES OF PILOT-UNIT TEST 2
Sample
Description
Lab Ident No.
Size Consist.
wt °» retained
on stated size
10
14
20
30
40
60
80
100
ZOO
325
Pan
Feed I
Initial
drum of feed
20883
2.1
7.5
41.3
18.2
12.3
11.7
4.3
2.0
0.4
0.1
0.1
Feed II
Final
drum of feed
20884
1.1
3.4
24.2
17.6
16.1
21.2
10:4
4.9
1.0
0.0
0.1
5
1 1 treated coal
,-eiver (bottom)
to 1/1 hr ~>
20HHO
0.5
2.0
18.3
13.6
14.1
20.1
10.4
4.3
5.9
4.0
6.8
^
/3 to 1-1/3 hr
20888
0.7
2.7
22.6
15.5
15.3
10.3
P. 9
3.4
4.5
2.0
3.1
Sample No.
5
-1-1/3 to
2 hr
20887
0.5
2.0
18.1
16.1
16.6
'.4.1
10.9
5.0
4.5
1.3
0.9
2
~2 to
2-2/3 hr
Z0886
0.4
1.2
15.5
14.5
16.2
26.6
13.0
6.0
4.7
1.2
0.7
1
Final treate
in receiv«
~2 2/3 to 3-
20685
0.2
1.0
19.1
20.9
19.2
23.8
8.7
3.9
2.5
0.5
0.2
Reactor
Reactor » esidue
at end of test
20891
0.5
7.6
61.5
19.7
7.6
2.3
0.3
0.2
0.1
0.1
0.1
-------
TABLE 15. SAMPLE ANALYSES FOR RUN 3 (N?, 600 F, WITHOUT LIME)
Sample Feed Reactor
Lab Ident No. Z0907 20894
ANALYSIS:
Proximate, wt %
Moisture 3.72 0.7
Volatiles 36.1 32.8
Ash 9.8 13.1
Fixed Carbon 51.38 53.4
Ultimate, wt %
Ash (dry) 10.20 13.20
Carbon 69.32 68.20
Hydrogen 4.76 4.36
Sulfur 2.62 2.55
Oxygen 11.89 10.59
Nitrogen 1.21 1.10
Carbon Dioxide --
Bulk Density.lb/cu ft 48.9 51.3
Screen,% retained on
10 0.0 1.3
14 0.6 3.1
20 16.4 26.5
30 14.6 18.1
40 17.0 16.7
60 26.4 20.7
80 15.5 8.5
100 7.1 3.3
200 2.1 1.6
325 0.1 0.1
Pan 0.2 0.1
Receiver
20893
0.7
31.2
11.0
57.1
11.03
70.3
4.26
2.64
10.58
1.19
39.3
5.2
31.7
20.0
43.1
21.14
58.20
3.67
3.39
12.66
0.94
26.8
0.9
1.7
20.6
18.4
19.8
23.8
8.7
3.0
2.4
0.5
0.2
0.0
0.3
0.3
0.3
0.0
0.3
0.3
0.3
8.3
17.6
72.3
A-14-118
TABLE 16. SAMPLE ANALYSES FOR RUN 4 (N0, 800°F, WITHOUT LIME)
Sample
Lab Ident No.
ANALYSIS:
Proximate,wt %
Moisture
Volatiles
Ash
Fixed Carbon
Feed
20907
3.72
36.1
9.8
51.38
Reactor
20925
0.4
20.1
17.8
61.7
Discharge
Receiver Tube
20926
0.00
23.1
14.8
62.1
20924
0.6
19.4
8.7
71.3
Ultimate, wt /°
Ash (dry) 10.20 17.89
Carbon 69.32 67.35
Hydrogen 4.76 3.43
Sulfur 2.62 2.47
Oxygen 11.89 7.60
Nitrogen 1.21 1.26
Carbon Dioxide
Bulk Density,lb/cu ft 48.9 36.21
Screen, % retained on
10 0.0 2.2
14 0.6 8.2
20 16.4 40.8
30 14.6 21.1
40 17.0 13.6
60 26.4 10.0
80 15.5 2.5
100 7.1 0.8
200 2.1 0.5
325 0.1 0.2
Pan 0.2 0.1
55
14.81
69.60
3.79
2.39
8.14
1.27
34.4
8.77
76.12
3.58
1.77
8.27
1.49
27.0
1.5
1.8
14.5
17.0
20.7
26.6
10.7
4.1
2.7
0.3
0.1
10.3
9.6
23.4
14.1
13.7
15.8
6.4
2.8
2.6
0.7
0.6
A-14-119
-------
TABLE 17. PILOT-UNIT RUN 5 (N0, 825°F)
ANALYSIS
Proximate, wt %
Moisture
Volatile
Ash
Fixed Carbon
Ultimate, wt %
Ash (dry)
Carbon
Hydrogen
Sulfur
Oxygen
Nitrogen
Coal Feed
3.72
36.1
9.8
51.38
10.20
69.32
.76
.62
4.
2.
11.89
1.21
Sulfur/Carbon Ratio 0.0378
Bulk Density, Ib/cu ft 48. 9
Screens,
10
14
20
30
40
60
80
100
200
325
Pan
retained on
0.0
0.6
16.4
14.6
17.0
26.4
15.5
7. 1
2.1
0.1
0.2
Reactor
Material
0.5
16.3
13.8
69.4
13.86
72.82
3. 12
2.15
6.63
1.42
0.0295
33.6
0.4
2.8
26.2
20.3
18.2
19.3
7.3
3.0
1.9
0.3
0.3
Coal Receiver
Top Middle Bottom
0.4
22.3
13.6
63.7
13.70
70.49
3.79
2.29
8.48
1.25
0.0325
32.3
3.9
3.1
15.8
13.9
16.5
24.4
12.4
5.5
3.9
0.3
0.3
0.8
19.5
12.5
67.2
12.61
72.61
3.23
1.86
8.29
1.40
0.0258
23.5
1. 1
7.0
33.7
22.2
16.5
13.2
4.0
1.3
0.6
0.2
0.2
0.7
13.4
14.0
71.9
14. 13
75. 10
2.60
2.22
4.96
0.99
0.0296
21.8
6.8
9.4
22.2
16.2
15.2
16.4
7.0
2.8
2.6
0.8
0.6
A-14-120
TABLE 18. PILOT-UNIT RUN 6 (N? AND H2, 850°F, 50 Ib/hr COAL)
Feed Coal
N2
Treated
Treated
Reactor
ANALYSIS
Proximate, wt %
Moisture
Volatile
Ash
Fixed Carbon
3.72
36. 1
9.8
51.38
0.5
21.2
14.9
63.4
0.3
18.5
11.5
69.7
0.7
19.3
18.7
61.3
Ultimate, wt
Ash (dry)
Carbon
Hydrogen
Sulfur
Oxygen
Nitrogen
10.20
69.32
4.76
2.62
11.89
1.21
15.00
69.20
3.31
2.38
8.81
1.30
11.56
73.24
3.42
1.73
8.56
1.49
18.84
66.24
3.06
2.63
7.74
1.31
Bulk Density, Ib/cu ft 48.9
Screens,
10
14
20
30
40
60
80
100
200
325
Pan
% retained on
0.0
0.6
16.4
14.6
17.0
26.4
15. 5
7. 1
2. 1
0. 1
0.2
36.6
4.0
1.0
6.6
9.3
15.6
30.4
17.6
8.6
6.0
0.6
0.3
24.3
2.8
6.4
31.8
21.0
16.6
13.7
4.2
1.6
1.5
0.3
0. 1
33.4
9.1
7.4
35.7
17.9
12.3
9.7
3.0
1.3
1.8
0.8
1.0
56
A-14-121
-------
TABLE 19. TIME-TEMPERATURE MATRIX FOR PILOT-UNIT RUNS
Feed Rate, Ib/hr Temperature, F
Ui
(Residence Time,
min)
25 (120)
50 (60)
100 (30)
200 (15)
750 800 850 900 950
13
8 B 9C 6, 9B 8 A 9A
11
12B
1000
7
10
1100
12A
-------
TABLE 20. PILOT-UNIT RUN 7 (H2, 1000°F, 50 Ib/hr MIX)
Receiver
Feed
Coal Tr-> Middle Bottom Reactor
ANALYSIS
Proximate, wt %
Moisture
Volatile
Ash
Fixed Carbon
Ultimate, wt %
Ash (dry)
Carbon
Hydrogen
Sulfur
Oxygen
Nitrogen
3.9 0.0
37.4 10.1
9.6 65.9
49.1 24.0
9.98
69.14
4.46
3.33
11.91
1. 18
65.93
25.63
1.16
2. 17
4.66
0.45
0.0
11.4
51.3
37.3
51.31
38.90
1.63
2.12
5.33
0.71
0.0
11.7
46.7
41.6
46.77
43. 10
1.75
2.70
4.88
0.80
0.0
10.1
64.4
25.5
64.41
27. 13
1.30
2.44
4.25
0.47
Bulk Density, Ib/cu ft 49.3 47.3
Screens,
10
14
20
30
40
60
80
100
200
325
Pan
% retained on
0.1
0.6
14.5
14.0
16.0
26.6
16.2
7.9
3.6
0.2
0.3
0.2
0.7
5.1
7.6
18.2
31. 1
15.4
6.8
10.2
3.4
1.3
30.9
1.7
9. 1
22.0
14.9
18.5
20.2
6.5
2.7
3.0
0.9
0.5
29.4
2.0
13.6
28.1
14.0
15.5
16.2
4.6
1.8
2.8
0.9
0.5
39.7
1. 1
7.6
21.4
12.
22.
23.
,7
1
,5
6.0
1.8
2.0
1.0
0.8
A-14-122
TABLE 21. PILOT-UNIT RUN 7, FURTHER DETAIL
Coal Receiver Top
Proximate Analysis, wt %
Moisture
Volatile
Ash
Fixed Carbon
Ultimate Analysis, wt %
Ash (dry)
Carbon
Hydrogen
Sulfur (total)
Sulfide
Sulfate
Pyritic
Organic
Oxyg en
Nitrogen
COa
Nonpyritic Iron
Total
0.0
10. 1
65.9
24.0
65.93
24.96
1. 16
1.89
0.83
0. 17
0.06
0.83
3. 17
0.45
2.44
0.87
Float
0.40
14.80
,r, 4
2L.46
65.63
2.77
1.83
0.22
0. 17
0. 10
1.34
. 12
i 18
I 01
i 03
Sink
0.00
77.7
77.76
11.76
0.91
1.88
1.09
0.20
0.07
0.52
4.04
0. 17
3.48
0.78
A-14-123
58
-------
TABLE 22. PILOT-UNIT RUN 8A (H.
Proximate Analysis, wt %
Moisture
Volatile
Ash
Fixed Carbon
Ultimate Analysis, wt %
Ash ( dry)
Carbon
Hydrogen
Sulfur (total)
Sulfide
Sulfate
Pyritic
Organic
Oxygen
Nitrogen
CO2
Bulk Density, lb/cu ft
Screens, % Retained on
10
14
20
30
40
60
80
100
200
325
Pan
Reactor
Material
0.0
22.2
Z8.4
49.4
28.41
54.60
3.23
2. 18
10.57
1.01
41.3
0.1
1.5
31. 3
18.5
17.2
19.8
6.3
2.4
2.2
0.4
0. 3
900°F, 50 Ib/hr MIX)
Coal Receiver
Total Float
0.0
11.5
66.6
31.9
66.63
22.86
1.32
1.80 1.92
0.84 0.03
0.26 0.09
0.12 0.21
0.58 1.59
5.97
0.43
2.72
52. 1
0. 1
0.5
3.7
6.4
21. 1
40.7
15. 1
5. 2
5. 2
1. 3
0.7
Sink
1.70
0.85
0. 16
0. 11
0. 58
A-14-125
TABLE 23. PILOT-UNIT RUN 8B (H2, 750 F, 50 Ib/hr MIX)
Coal Receiver
Proximate Analysis, wt °
Moisture
Volatile
Ash
Fixed Carbon
Ultimate Analysis, wt %
Ash (dry)
Carbon
Hydrogen
Sulfur (total)
Sulfide
Sulfate
Pyritic
Organic
Oxygen
Nitrogen
CO2
Bulk Density, lb/cu ft
Screens,
10
14
20
30
40
60
80
100
200
325
Pan
% retained on
Total Float
0.0
19.7
47.8
32.5
47.81
36.56
2.35
2.08 2.11
0.64 0.05
0. 24 0. 15
0. 20 0. 34
1.00 1.57
8.55
0.66
1.99
54.4
0.0
0.1
2.6
4.6
13.9
36.6
19.5
9.3
9.6
2.3
1.5
Sink
2.05
1. 31
0.31
0.24
0. 19
A-14-126
59
-------
TABLE 24. PILOT-UNIT RUNS 9A AND 9B (H2> 950° AND 850°F, 50 Ib/hr MIX)
Run 9A
Proximate Analysis, wt %
Moisture
Volatile
Ash
Fixed Carbon
Ultimate Analysis, wt %
Ash (dry)
Carbon
Hydrogen
Sulfur (total)
Sulfide
Sulfate
Pyritic
Organic
Oxygen
Nitrogen
C02
Bulk Density, Ib/cu ft
Screens, % retained on
10
14
20
30
40
60
80
100
200
325
Pan
Total
0.0
10.6
68.5
20.9
68.49
23.93
1.29
1.91
1.00
0. 28
0.08
0.55
1.03
0.43
2.92
50.9
0.5
0. 3
1.4
4.0
18.9
44. 1
17.6
5.9
5.4
1.4
0.5
Float
0.9
15.7
16.8
66.6
17.00
67.44
2.83
1.95
0. 14
0. 20
0. 15
1,46
8.56
1.26
0.96
Sink Total
0.00 0.0
12. 1
81.00 60.7
27.2
81.04 60.73
6.45 28.95
0.80 1.55
1.80 1.58
1. 22
0. 27
0. 10
0. 21
6.29 4.69
0. 11 0.48
3.51 2.02
43.9
0. 3
0.9
3.8
8.4
25. 5
39.8
13.0
4.2
3. 1
0.6
0.4
Run 9B
Float Sink
1. 1
18.6
14.7
65.6
14.91
68. 16
3.20
1.92
0. 16
0. 15
0. 19
1.42
9.38
1. 17
1.26
0.00
84.5
84.49
4.39
0.90
1.31
0.79
0.33
0. 11
0.08
5.65
0.08
3. 18
A-14-124
TABLE 25. PILOT-UNIT
Proximate Analysis, wt ^
Moisture
Volatile
Ash
Fixed Carbon
Ultimate Analysis, wt ^
Ash (dry)
Carbon
Hydrogen
Sulfur (total)
Oxygen
Nitrogen
C02
Bulk Density, Ib/cuft
Screens, % retained on
10
14
20
30
40
60
80
100
200
325
Pan
RUN 9C
/TT
\nirj J
Total
0.0
17.3
44.4
38.3
44.44
41.01
2.29
2.09
7.23
0. 68
2.26
45.3
0.1
0.2
0.8
3.6
15.8
39.0
20.8
8.8
8.5
1.6
0.8
800°F, 50
Float
1.0
21.6
10.6
66.8
10.74
72.22
3.69
1.98
9.31
1.39
0.67
Ib/hr
Sink
0.0
..
83.6
__
83.61
4.88
0. 58
2.18
4.78
0.09
3.88
A t A 11
MIX)
i *
60
-------
Run 9C (Table 25) at 800°F resulted in performance similar to the pre-
vious runs.
ANALYSIS OF TEST RESULTS
Figures 22 and 23 present the pyritic sulfur and organic sulfur contents
of the samples at different temperatures. Both batch and pilot-unit tests
caused the pyritic sulfur content to decrease as the temperature increased.
However, in these tests the organic sulfur was not reduced enough to achieve
the final content desired. Because the rate of organic sulfur removal was not
faster than the devolatilization rate, the fraction of organic sulfur in the
remaining treated coal was nearly constant.
CONCLUSIONS
Data from both the batch and pilot units indicated that, although some
sulfur was being removed and the getter concept was viable, the degree of
sulfur removal was insufficient. Sulfur reduction to values below 1% is
necessary for the treated product to meet the Federal standards for S02
emission.
After a review of kinetic data (next section), it was decided to redirect
the program to acquire more basic data on smaller-scale equipment.
61
-------
3?
— ^ *»
L£. 1
=> <
i O
— * {J
W Q
LJ
0 H
|S
IP
Q_ ~
Z
0.5
0.45
0.40^
0.35
0.30
0.25
0.20
0.15
0.10
0.05
n
P O PILOT TESTS
L A BATCH TESTS
_ _
—
A
0 °
A A 0
0
A
bi
till
600
700
800 900
TEMPERATURE, °F
1000
MOO
A-63-809
Figure 22. Percent pyritic sulfur in treated coal.
2.0
1.5
0.5
1
O PILOT TEST TOTAL SULFUR
• BATCH TEST TOTAL SULFUR
A PILOT TEST ORGANIC SULFUR
A BATCH TEST ORGANIC SULFUR
I i
600
700
800 900
TEMPERATURE, °F
1000
1100
A-63-810
Figure 23. Percent total and organic sulfur in treated coal.
62
-------
KINETIC STUDIES OF OUTSIDE DATA
The studies of Vestal and Johnston (1969) (6) indicate that much of the
organic sulfur should be removed prior to pyrite decomposition. They confirm
the work of Snow (1932) (5) that slow heat-up rates provide better sulfur
release than fast heat-up. They also indicate that sulfur can be fixed into
the carbon lattice in a reverse reaction. The configuration of the fluidized-
bed reactor employed in this program caused rapid (about 100°-500°F/s) heat-up
from ambient to bed temperatures. These factors suggested that greater sulfur
removals might be possible if the reactor configuration permitted slow heat-up
and inhibited back-reaction. Therefore, a kinetic analysis of the data of
Vestal and Johnston was made to determine potential sulfur removal made possible
by this technique.
A short computer program was prepared to study the expected reactor
operation based on the kinetic parameters reported by Vestal and Johnston (6) .
For the first studies, the assumption was made that these kinetics applied to
the rapid heat-up in the pilot-unit, fluidized-bed reactor. A completely back-
mixed reactor (a theoretically perfect fluidized bed) was assumed for the
reactions; hydrogen and coal feed rates were similar to those used in the pilot-
unit program. Temperature, residence time, and lime-to-coal ratio were the
major parameters varied in this calculational program. Figures 24 through
28 illustrate the results.
Figure 24 shows the expected amount of pyritic sulfur remaining as a
function of temperature and reaction time. Because the calculations assumed
that there can be no back-reaction with hydrogen sulfide to remanufacture iron
pyrite, pyrite removal should be independent of lime content. Significant
pyrite removal should be achieved at 900° to 950°F with sufficient reaction
time. These results confirm the ability to decompose pyrite in the pilot unit.
Figure 25 presents the expected removal of nonfixed organic sulfur as a
function of temperature and reaction time. This graph assumes no back-reaction
of sulfur. It illustrates that the amount of available organic sulfur remain-
ing in the coal will be quite low at 850°F and a 30- to 60-minute reaction
time. The kinetics do provide a mechanism for fixation of the available
sulfur by a reaction of the coal char with H2S. Figure 26 illustrates this
effect. With large lime additions, the amount of sulfur fixation is negligible.
This can be seen by comparing the data in Figure 25 (5-minute reaction time)
with the largest lime addition of Figure 26. As lime addition is decreased,
a significant portion of the previously available sulfur becomes fixed into
the coal. Figure 27 illustrates sulfur fixation at various reaction times
with stoichiometric excess-lime-addition rates, and Figure 28 illustrates the
fixation with insufficient lime content.
63
-------
1.0
REACTION
TIME.mln'
800 900
TEMPERATURE,"F
1000
A-63-947
Figure 24. Removal of pyritic sulfur.
0.0
700 800 900 1000
TEMPERATURE,°F A-63-948
Figure 25. Removal of nonfixed organic sulfur.
64
-------
800 900
TEMPERATURE, °F
1000
A-63-949
Figure 26. Fixation of available organic sulfur as a function
of temperature and lime content.
800 900
TEMPERATURE,°F
1000
A-63-950
Figure 27. Fixation of organic sulfur with excess CaO present,
65
-------
1.0
o.s
"
0.4
oo
-------
These graphs assume that the kinetic parameters reported by Vestal and
Johnston (6) are applicable for the fast heat-up rate and isothermal bed
characteristics of our pilot-unit reactor. The work in the initial program
phase has confirmed their high fraction of pyritic sulfur removal, but the
organic sulfur removal does not agree. Either the high heat-up rates fixed
the organic sulfur and thus the kinetics did not apply, or the primary coal
sample had a high percentage of previously fixed organic sulfur.
The calculational program was modified and evaluated for slow heat-up
rates as opposed to the fast rates calculated above for fluidized-bed studies.
Figures 29 and 30 present the mole fractions of the various sulfur constituents
of the coal as the coal is heated in the presence of hydrogen at a rate of
9°F/min. In Figure 29, representing coal treatment without lime, one type of
available organic sulfur is significantly removed at a temperature of 750°F;
another, at 870 F. The hydrogen sulfide concentration of the gas at these
temperatures is several thousand parts per million; therefore, some sulfur is
being refixed into the coal.
The pyrites do not show significant decomposition at 900°F, confirming
the observations made in this preliminary thermobalance work (discussed in the
next section). Similarly, the iron sulfide formation is not yet high.
In Figure 30 the system was recalculated with large lime additions.
Decomposition of the available organic sulfurs and pyrites must, of course, be
similar to that in Figure 29 because no mechanism is given for back-reactions.
Hydrogen sulfide concentration decreases because of the calcium sulfide
formation. Consequently, the formation of fixed sulfur in the coal is reduced.
The fixed sulfur appears to be decreasing at higher temperatures even before
the iron sulfide is significantly decomposed.
The relative temperatures of fixed sulfur and iron sulfide decomposition
shown in Figure 30 appear to contradict the original data in the Vestal and
Johnston report (6) . This may be due to the effect of lime on the decomposition
of fixed sulfur or may be caused by the high sensitivity of the kinetic rate
expressions to temperature. A slight error in the calculation of the decom-
position rate or the initial presentation of the kinetic-rate data will have a
significant effect on the resultant figures.
67
-------
LIME-FREE
10-2
10-3
S 10-4
o
E
(T
I-
UJ
O
I
ID'5
IO'6
10-7
400 500 600 700 800
TEMPERATURE, °F
900
1000
A-73-1050
Figure 29- Coal sulfur fractions heated without lime in the presence of
hydrogen.
68
-------
c
o
S 10"* -
o
E
Z
LU
O
Z
o
o
HIGH LIME ADDITION
400 500 600 700 800
TEMPERATURE, °F
900
1000
A-73-IO5I
Figure 30. Coal sulfur fractions heated with high lime additions in
the presence of hydrogen.
69
-------
PROGRAM REDIRECTION - END OF PHASE I, START OF PHASE II
Considering the results from batch tests, pilot tests, and the kinetic
studies, a change in the program was desirable. Two basic factors could have
caused the discrepancy between the initial sulfur removal results and that
reported by other investigators:
1. The primary coal sample, chosen for availability and substantial cost
saving, was highly weathered. This weathering may have fixed some
of the sulfur into the carbon lattice of the coal, making removal
difficult.
2. The configuration of the pilot-unit reactor, with nearly instantaneous
heat-up, may cause sulfur fixation.
Consequently, the program was redirected to evaluate these effects.
A thermobalance was used for initial testing. One was available for pre-
liminary testwork with the initial coal sample. These tests were run with the
thermobalance at a 10°F/min heat-up rate to 900°F and 10 SCF/hr hydrogen flow.
In each test, 1.8 grams of solid material was charged and the feed was screened
to —10+20 mesh, a size governed by the mechanical requirements of the equipment.
The first test was operated with coal only, to obtain reference data on
devolatilization and desulfurization of the coal in a hydrogen atmosphere.
The second test used the standard coal-to-lime weight ratio of 2:1. However,
the coal and lime contact was not good because there was no movement or mixing
as in a fluidized-bed system. The third test was operated with a coal-to-lime
ratio of 1:2 to increase the contact of the coal with the lime particles.
Laboratory analyses of the samples are presented in Tables 26 and 27.
The total sulfur contents of the three feed samples were essentially identical,
from 3.03% to 3.12%, when based on coal weight. This is a slightly higher
percentage of sulfur than was shown in other tests, but the percentage may be
consistent with the screen size fraction used (the larger particles appear to
contain a greater fraction of sulfur).
In the first test the devolatilization was 25% and sulfur reduction was
45% of the original sulfur in the coal. Thirty-five percent of the organic
sulfur was removed, and 53% of the pyritic sulfur decomposed.
The total sulfur loss to the gases decreased as lime was added, indicating
sulfur recovery by the lime. In Test 3, for example, nearly all of the sulfur
in the coal was recovered in the lime-coal residue. Also, because of volatile
sorption into the lime pore structure, the devolatilization losses in Tests 2
and 3 were only about 21% of the original coal weight. In Test 2, the
70
-------
Test No.
Coal/Lime Ratio
Sample
Lab Ident. No.
Sulfur Composition, wt %
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial Sample
Treated Sample
Weight Loss, %
TABLE 26. BASIC DATA - THERMOBALANCE RUNS
CTB-1 CTB-2
No lime
Feed Residue
21910
21911
2:1
Feed Residue
21917
21918
0.00
0.36
1.06
1.69
3.11
0.05
0.10
0.66
1.47
2.28
1 .8440
1.3839
24.95
0.00
0.27
0.90
0.85
2.02
0.21
0.22
0.50
0.70
T~58~
1.9668
1.6881
14.17
CTB-3
1:2
Feed Residue
21932
21933
0.00
0.15
0.41
0.48
1.04
0.16
0.19
0 36
0.31
1.02
2.1070
1.9585
7.05
A-14-127
-------
TABLE 27. THERMOBALANCE RUNS - REDUCED DATA
Test No.
CTB-?
CTB-2
CTB-3
Stream
Feed
Weight Loss,
fraction of coal
Residue
24.95
Sulfur Weight,
based on 100 -Ib
Sulfide
Sulfate
Pyritic
Organic
Total
coal
0.0
0.36
1.06
1.69
3.11
feed, Ib
0.038
0.075
0.49
1.10
1.71
Sulfur
Removal,
%
—
79.2
53.3
34.7
45.0
Feed
Sulfur
based
coal
0.0
0.405
1.35
1.27
3.03
Residue
21.25
Weight,
on 100 -Ib
feed, ib
0.27
0.28
0.64
0.97
2.16
Sulfur
Removal,
%
--
30.0
53.3
24.0
28.7
Feed
Sulfur
based
coal
0.0
0.45
1.23
1.44
3.12
Residue
21.15
Weight,
on 100 -Ib
feed, Ib
0.45
0.529
1.00
0.86
2.84
Sulfur
Removal,
%
--
(17.7)
26.2
40.0
8.9
A-14-128
-------
percentage of pyrite reduction was similar to that of Test 1, but more organic
sulfur remained in the residue. This might also be attributed to the sorption
of volatile matter. Test 3, however, showed improved organic-sulfur removal
and decreased pyritic removal.
Significant sulfur removal was achieved in these tests, as evidenced by
the 45% reduction in Test 1 and the calcium sulfide manufactured in the other
two tests. However, when devolatilization of the coal is considered, the net
sulfur content of the treated coal calculates to about 2%. Removal of pyritic
sulfur is not so great as in the pilot-unit tests because the sample was not
maintained at the high temperature for an extended time.
73
-------
SELECTION OF COAL FOR EXTENSIVE STUDY
The promising results from the three tests discussed above indicated that
further thermobalance work was justified. Another unit was rebuilt for
application in this work because the one used for the initial test was not
available for extensive use.
The first runs in the rebuilt unit were made with the original, weathered
Illinois No. 6 coal on hand. Four tests were made for unit shakedown and to
establish operating procedures. Table 28 presents the data from the laboratory
analyses for Runs TB-5 to TB-10. These were all made with a 2:1 coal-lime
mixture, heated at 5°F/min to terminal temperatures of 700° to 1000°F. All
tests were made with hydrogen except Run TB-5, which was made with nitrogen.
A comparison of TB-5 with TB-8 shows the benefits of hydrogen usage at 900°F.
The data indicate that as the temperature increased to 900 F the sulfur
decreased.
Examination of the reduced data, calculated on a basis of 150 pounds of
feed, (100 pounds of coal, 50 pounds of lime) shows formation of calcium
sulfide. The calcium sulfide formation is proved because the amount of sulfur
as sulfide is greater than the amount that would appear as ferrous sulfide
from pyrite decomposition. Also, there is less sulfur in the residue than in
the feed, indicating a loss (probably as H^S) from the system, possibly because
of relatively poor contact with lime and hydrogen sulfide. In the tests after
TB-10, when lime was used, the ratio was changed to a 1:2 coal-lime mixture to
improve the contact.
The next test series, TB-11 to TB-21, shown in Table 29, was performed on
several new coal samples to select one sample for exhaustive testing. All the
tests were run with the new 1:2 coal-lime mixture and were hydrogen-treated.
They were heated at 5°F/min to 900°F, except TB-18 (800°F) and TB-20 (1450°F).
Tests TB-19 and TB-20 were not held at the terminal temperatures, while the
rest were held at the terminal temperature for 30 minutes.
Laboratory data and the values calculated in Table 29 were used for
selection of the coal for further testing. Two lower rank coals, Montana sub-
bituminous and North Dakota lignite, were excluded because their initial sulfur
content was too low to respond to treatment. Similarly, the samples of
Pittsburgh seam (Pennsylvania mine) and Illinois No. 6 were sufficiently low
in original sulfur content that they would require less intense thermal expo-
sure for sufficient sulfur release. Of the three coal samples remaining, the
Western Kentucky No. 9 (an abundant Midwestern type) had the highest sulfur
content and the highest after treatment, indicating that this coal would
require the most extreme treatment conditions. These conditions, when deter-
mined, should be sufficient for the other coal materials available for initial
74
-------
TABLE 28. THERMOBALANCE RUN DATA (ILLINOIS NO.
Ui
Run No.
Coal Type
Heating Rate, ° F/min
Terminal Temperature, °
Holding Time, min
Lab Analysis, wt %
HjO
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritlc
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
* Weathered coal.
Coal
0.00
0. 32
0.89
1.79
3.00
100.00
0.00
0. 32
0.89
1.79
3.00
0.00
0. 32
0.89
Feed mixture
0.00
0.21
0.60
1. 20
2.01
150.00
0.00
0. 32
0. 89
1.79
3.00
0.00
0. 32
0. 89
3.00
3. 00
TB-5
5
900
0
Residue
0.06
0.08
0. 73
1. 09
1.96
4.6162
4.0075
13. 18
19. 78
130. 23
0.08
0. 10
0. 95
1.42
2. 55
1. 18
1.77
2. 95
TB-6
Illinois No. 6*
5
700
0
Residue
0. 05
0. 12
0.41
1.09
1.67
4. 5115
4. 3042
4.59
6.89
143. 12
0.07
0.17
0. 59
1.56
2.39
0.63
1.68
2. 31
SOIS NO.
TB-7
5
800
0
Residue
0.30
0. 10
0. 27
Q. 98
1.65
4. 2482
3.7937
10.70
16.08
133.95
0.40
0.13
0.36
1.31
2. 20
0.43
1. 56
1. 99
6 COAL)
TB-8
5
900
0
Residue
0. 50
0. 10
0. 16
0.82 '
1.58
4. 3311
3.6153
16.53
24.79
125.21
0.63
0.13
0. 20
1.03
1.99
0. 27
1.37
1.64
TB-9
5
1000
0
Residue
0.72
0.07
0.20
0.81
1.80
4.1620
3.4312
17.56
26.34
123.66
0.89
0.09
0.25
1.00
2.23
0.34
1. 36
1.70
TB-10
5
800
0
Residue
0.34
0.10
0. 20
0.97
1.61
4. 2689
3. 9038
8.55
12.83
137.18
0.47
0.14
0.27
1.33
2.21
0. 31
1.53
1.84
B75123042
-------
TABLE 29. THERMOBALANCE RUN DATA - VARIOUS COALS
ON
Run No.
Coat Type
Heating Rate, "F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sutfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 100.00
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
TB-11
W.
Coal
5. 9
33.4
0.00
0.07
2. 30
0.97
3. 34
Kentucky
5
900
30
Mixture
0.00
0.02
0.77
0.32
1. 11
No. 9
Residue
0. 54
0.04
0. 11
0. 38
1.07
TB-12
TB-13
5.0333
300.00
4.4302
11.98
35.95
264.06
Coal
9To~
34. 5
0.00
0.07
2.02
1. 24
3. 33
100.00
Indiana No. 5
5
900
30
Mixture
0. 00
.02
4.0500
300.00
Residue
0.21
0. 16
0. 16
0.29
0.82
3. 5607
12.08
36.2-1
263.76
Pittsburgh Seam (Pa.
Coal
lT5~~
27.6
0.00
0.04
1.08
0.26
1. 38
100.00
900
30
Mixture
4.3800
300. 00
Residue
0. 11
0.0-1
0. 14
0.06
0. 35
3.9937
8. 82
26.46
273. 54
0.00
0.07
2.30
0.97
3. 34
0.00
0.07
2. 30
0.97
3. 34
1.43
0. 11
0.29
1.00
2.83
0.00
0.07
2.02
1.24
3. 33
0. 00
D.07
2.02
1.24
3. 33
0. 55
0. 42
0. 42
0.76
2. 15
0.00
0.04
1.08
0.26
I. 38
0. 00
0.04
1.08
0.26
1. 38
0. 30
0. 11
0. 38
0. 16
0.95
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
0.00
0.07
2. 30
0.97
3. 34
0.00
0.02
0.77
0. 32
1.11
0.45
1. 56
2.01
0.00
0.07
2.02
1.24
3. 33
0.00
0.02
0.67
0.41
1. 10
0. 65
1. 19
1.84
0.00
0.04
1.08
0. 26
1.38
0.00
0.01
0. 36
0.0')
0.46
0. 52
0,22
0.74
61.4
64.6
60.9
B75123044a
-------
TABLE 29. THERMOBALANCE RUN DATA - VARIOUS COALS (Continued)
TB-14
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
Pittsburgh Seam (W. Va. )
5
900
30
Coal
7.7
33.8
0.00
0.05
1.49
1. 37
2.91
100. 00
0.00
0.05
1 . 49
1. 37
2.91
0.00
0. 05
1.49
1. 37
2.91
Mixture
0.00
0.02
0. 50
0. 46
0. 98
4. 5220
300. 00
0. 00
0. 05
1.49
1. 37
2.91
0.00
0.02
0. 50
0.46
0.9B
Residue
0. 10
0.06
0. 11
0.33
0. 60
3.9811
11.98
35.96
264.04
0.26
0. 16
0.29
0.87
1. 58
0.45
1. 35
1.80
TB-15
Montana Subbituminous
5
900
Coal
1771T
35.7
0.00
0.00
0.29
0. 37
0766
100.00
0.00
0.00
0.29
0. 37
0. 66
0.00
0.00
0.29
0. 37
0. 66
30
Mixture
0.00
0.00
0. 10
0. 12
0.22
4.2117
300. 00
0.00
0.00
0.29
0. 37
0766
0.00
0.00
0. 10
0. 12
0.22
Residue
0.02
0.04
0. 10
0.06
0772
3. 5817
14.96
44.88
255. 12
0.05
0. 10
0.26
0. 15
0.56
0.47
0.27
0.74
TB-16
Illinois No.
S
900
Coal
24.5
32.0
0.00
0.04
0.21
0.28
0. 53
100.00
0.00
0.04
0.21
0.28
0. 53
0.00
0.04
0.21
0.28
0.53
30
Mixture
0.00
0.01
0.07
0.09
0. 17
4.7967
300.00
0.00
0.04
0.21
0.28
0. 53
0.00
0.01
0.07
0.09
0. 17
6
Residue
0.01
0.08
0. 16
0.00
0.25
4.0177
16.24
48.72
251.28
0.02
0.20
0.40
0.00
0.62
0.78
0.00
0.78
60. 1
37.9
24. 5
B75123044a
-------
TABLE 29. THERMOBALANCE RUN DATA - VARIOUS COALS (Continued)
oo
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide 0.00
Sulfate 0.07
Pyritic 2.30
Organic 0.97
Total 3. 34
Sulfur Content, wt %, as
Sulfide 0.00
Sulfate 0.07
Pyritic 2. 30
Organic 0.97
Total 3. 34
Wt % Original Sulfur Removed
From Feed
TB-17
W.
Coal
5.9
33.4
0.00
0.07
2. 30
0.97
3. 34
Kentucky
5
800
30
Mixture
0.00
0.02
0.77
0. 32
No. 9
Residue
0.57
0.06
0. 57
0. 30
1. 50
4.0215
100.00 300.00
0.00
0.07
2. 30
0.97
3. 34
0.00
0.02
0.77
0. 32
1.11
3.7017
7.95
23. 85
276. 15
a
v*
00
a
p
Coal
5.
24.
0.
0.
1.
0.
1.
100.
0.
0.
1.
0.
K
0.
0.
1.
0.
1.
8
8
00
00
14
04
18
00
00
00
14
04
18
00
00
14
04
18
TB
-18
Illinois No. 6
5
900
30
Mixture
0.
0.
0.
0.
0.
4.
300.
0.
0.
1.
0.
l-
0.
0.
0.
0.
0.
00
00
38
01
39
9714
00
00
00
14
04
18
00
00
38
01
39
Residue
0.
0.
0.
-------
TABLE 29. THERMOBALANCE RUN DATA- VARIOUS COALS (Continued)
Ron No.
Coal Type
Heating Rate, T/tnin
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
HZO
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %. as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
w,
Coal
5.9
33.4
0.00
0.07
2.30
0.97
3. 34
100.00
0.00
0.07
I. 30
0.97
3; 34
0.00
0.07
2.30
0.97
3.34
TB-20
. Kentucky
5
1450
30
Mixture
0.00
0.02
0.72
0. 30
1.04
4. 6539
321.03
0.00
0.07
2. 30
0.97
3. 34
0.00
0.02
0.72
0.30
1.04
No. 9
Residue
0. 87
0.02
0. 16
0.21
1.26
3.9515
15.09
48.45
272. 59
2. 37
0.05
0.43
0. 57
3.42
0. 83
1. 11
1.94
70. 1
TB-21
Illinois No. 6
5
900
Coal
6. 6
28.5
0.00
0.00
0.81
0.24
1.05
100.00
0.00
0.00
0.81
0.24
1.05
0.00
0.00
0.81
0.24
1.05
30
Mixture
0.00
0.00
0.27
0.08
OT35
4.8698
t
300.00
0.00
0.00
0.81
0.24
1.05
0.00
0.00
0.27
0.08
0.35
Residue
0.05
0.04
0.14
0.09
OT32
4.4626
8.36
25.08
174.92
0. 14
0.11
0.38
0.25
0.88
0.51
0.33
0.84
40.00
B75123044b
-------
evaluation. Therefore, the Western Kentucky No. 9 coal was selected for
extensive study in this program.
THERMOBALANCE TESTS - WESTERN KENTUCKY NO. 9
Five runs, TB-22 to TB-26, were made with crushed and screened (—20+80
mesh) Western Kentucky No. 9 coal. This coal was mixed with lime for three
tests; Runs TB-24 and TB-26 used coal only. The heat-up rate was 5°F/min to
a terminal temperature of 800°F for Run TB-22 and 900°F for the others. All
tests included holding the sample for 30 minutes at the terminal temperatures.
Data and calculations for these five runs are in Table 30. The sulfur
removal ranged from 44% to 63% in these tests; however, the fraction of sulfur
remaining in the treated coal was still too great to meet the requirements of
direct combustion of the product. The lowest sulfur content was 1.73%,
exceeding the limits. More severe treatment was necessary.
Two important facts were established in these tests. First^ the sulfide
content of the residues was much lower in the lime-free tests than in the tests
with lime. This proves that calcium sulfide forms, but not so fast as the
sulfur is released from the coal, as shown by an imbalance in total sulfur.
Second, the residue was caked in the sample basket and had to be broken
up for removal and analysis. Poor solids-gas contact results from the caking
and the reactions are inhibited; sulfur removal should be enhanced if the coal
is noncaking.
A pretreatment step is required, for some coals, to prevent caking at the
thermobalance conditions. The caking is caused by the tendency of the coal to
become fluid at elevated temperatures. When partially fluid, the coal parti-
cles stick together. The coal can be pretreated by heating to a certain
temperature, usually 750 to 800°F, in an atmosphere of air until a small
quantity of oxygen has been consumed. Under these conditions, the "volatile
matter" content of the coal is reduced and the coal no longer becomes fluid at
the test temperature. Also, the coal particles form a skin, probably coke or
char, that can be evaluated microscopically. This skin also inhibits caking.
A batch reactor (modified) was used to pretreat coals for the test work.
Western Kentucky No. 9 coal is relatively easy to pretreat. The caking
tendencies can be destroyed by heating the coal, fluidized with air at atmo-
spheric pressure, to 750 F, reacting 1 SCF of oxygen per pound of coal. This
coal can also be pretreated using inert nitrogen treatment at 750°F for 30
minutes. Associated with the pretreatment is a weight loss of 15% total (11%
to 12% on a dry basis), including coal fines lost overhead. Volatile matter
content is reduced from 33% to 35% in the coal to 27% to 28% in the pretreated
coal. Its bulk density also decreases from about 50 Ib/cu ft to approximately
35 Ib/cu ft, because the particles tend to "puff." Other coals are pretreated
in a similar manner but may require more air, longer exposure time, or higher
temperatures.
80
-------
TABLE 30. THERMOBALANCE RUN DATA (WESTERN KENTUCKY NO. 9)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
HZ0
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, <#>
Of Total Weight
Of Coal Weight
Reduced Data
(100 lb Coal Originally)
Weight, lb
Sulfur Weight, lb, as
Sulfide
Sulfate
Pyritic
Of panic
\_/ 1. gmxLv^
Total
Sulfur Content, wt % , as
Sulfide
Sulfate
Pyritic
Organic
Total
W.
Coal
5.9
33.4
0.00
0. 07
2. 30
0. 97
3. 34
0. 00
0. 07
2. 30
0. 97
3. 34
0.00
0. 07
2. 30
0. 97
3. 34
TB-22
Ky. No.
5
800
30
Feed
0. 00
0.02
0.77
0. 32
1. 11
4. 5805
300. 00
0. 00
0. 07
2. 30
0. 97
3. 34
0.00
0.02
0.77
0.32
1. 11
9
Residue
0. 30
0.07
0. 34
0. 34
1.05
4. 1764
8.82
26.48
273. 52
0. 82
0. 19
0. 93
0. 93
2.87
1. 26
1. 26
2. 52
Wt % Original Sulfur Removed
From Coal
From Feed
*No lime.
44. 3
44. 3
TB-23
W.
Coal
5.9
33.4
0.00
0.07
2. 30
0. 97
3. 34
0. 00
0. 07
2. 30
0. 97
3.34
0.00
0.07
2. 30
0. 97
3.34
Ky. No.
5
900
30
Feed
0.00
0.02
0.77
0. 32
1. 11
4. 5869
300. 00
0.00
0. 07
2. 30
0. 97
3. 34
0.00
0. 02
0.77
0. 32
1. 11
9
Residue
0. 59
0. 05
0. 32
0. 30
1. 26
4. 1125
10. 34
31. 02
268. 98
1.59
0.13
0.86
0.81
3. 39
1,25
1. 17
2.42
50.0
50.0
B75123043
81
-------
TABLE 30. THERMOBALANCE RUN DATA (WESTERN KENTUCKY NO. 9) (Continued)
W. Ky. No. 9
5
900
30
Coal Residue
5.9
33.4
Run No. TB-24*
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide 0.00 0.72
Sulfate 0. 07 0. 05
Pyritic 2. 30 0.64
Organic Q. 97 1. 09
Total 3. 34 2. 50
Weight, g
Initial 4. 2304
Treated 3. 0028
Weight Loss, %
Of Total Weight 29. 02
Of Coal Weight 29.02
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 100.00 70.98
Sulfur Weight, Ib, as
Sulfide 0. 00 0. 51
Sulfate 0. 07 0. 04
Pyritic 2. 30 0.45
Organic 0. 97 0. 77
Total 3.34 1.77
Sulfur Content, wt % , as
Sulfide 0. 00
Sulfate 0. 07
Pyritic 2. 30 0. 64
Organic Q. 97 1. 09
Total 3.34 1.73
Wt <£ Original Sulfur Removed
From Coal 63.5
From Feed 63.5
*No lime.
TB-25
W
Coal
5.9
33.4
0. 00
0.07
2. 30
0. 97
3.34
0.00
0.07
2.30
0. 97
3.34
0. 00
0.07
2.30
0. 97
3.34
. Ky. No.
5
900
30
Feed
0.00
0. 02
0.77
0. 32
1. 11
4. 5726
300. 00
0.00
0.07
2.30
0. 97
3. 34
0.00
0.02
0.77
0. 32
1.11
9
Residue
0.36
0.04
0. 18
0. 37
0.95
4.0582
11. 25
33. 74
266. 26
0. 96
0.11
0.48
0.99
2. 54
0.72
1.49
2. 21
56.0
56.0
B75123043
82
-------
TABLE 30. THERMOBALANCE RUN DATA (WESTERN KENTUCKY NO. 9) (Continued)
Run No.
Coal Type
Heating Rate, ° F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt % , as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt "Ir Original Sulfur Removed
From Coal
From Feed
*No lime.
TB-26*
W. Ky. No. 9
5
900
30
Coal Residue
5.9
33.4
0.00
0.07
2. 30
0. 97
3.34
0.73
0.00
0.75
1.03
2.51
3.8131
100.00
2.7383
28.19
28.19
71.81
0.00
0.07
2.30
0. 97
3.34
0.00
0.07
2.30
0.97
3.34
0.52
0.00
0.54
0.74
1.80
0.75
1.03
1.78
61.7
61.7
B75123043
83
-------
A quantity of the Western Kentucky No. 9 coal was pretreated as described.
The pretreated coal was then screened to —20+40 mesh for use in the thermo-
balance and batch reactor tests. All subsequent calculations for the tables
sire based on a coal-lime feed that is made by taking an initial 100 pounds of
wet coal, pretreating it, and mixing the pretreated coal with lime (—60+80
mesh) in a 1:2 coal/lime ratio.
Results from a series of tests using pretreated coal are shown in Table 31.
Sulfur removals of 65% to 90% were attained. The first two runs, TB-27 and
TB-28, were heated at 5°F/min to 900°F terminal temperature and held for 30
minutes. Test TB-28 was run without lime. A reduction of pyritic sulfur was
achieved with the formation of sulfide. Much more sulfide was made in the test
with the lime than in the no-lime case. The organic sulfur reduction in these
two tests, however, is about equal to the weight loss. The lower organic
sulfur content in the residue from in the test with coal (no lime) may be due
to sulfur-bearing oils and tars that are absorbed by the lime in the mixed-feed
tests. These tests still yield a coal residue that is too high in sulfur.
Runs TB-30 and TB-31, also presented in Table 31, were heated to 1500°F
at 5°F/min with no holding. As expected, weight losses were much higher at
these temperatures. The residue from Test TB-30 has a lower sulfur content
than most of the earlier runs; however, it is difficult to allocate the sulfur
to the coal and lime when the residue is analyzed totally. Therefore, Test
TB-31 was made at the same condition and the residue was separated by the float-
sink method described earlier. The two fractions were then analyzed. The
removal of sulfur and redistribution of the total original sulfur is nearly the
same for Tests TB-30 and TB-31. The total amount of sulfur remaining after
treatment (per 100 pounds of initial coal) is 1.84 pounds for Test TB-30 and
1.83 pounds for Test TB-31. The distribution of the sulfur by types is also
similar. Assuming that the sulfide and sulfate remaining in the treated coal
can be washed or mechanically separated, the coal residue contains only 0.66%
total sulfur. This is an acceptable value depending upon the heating value of
the coal residue.
For additional comparisons, three more tests, shown in Table 32, were run
at a terminal temperature of 900°F and held for 30 minutes. The residue was
separated by the float-sink method or screened at 50 mesh into +50 and —50
fractions. The sulfur data from the different separation techniques scattered
widely; however, all sulfur contents were above the acceptable limits. The
conclusion, at this point, is that 900°F is not severe enough treatment to
effectively remove sulfur.
Table 33 lists the results and calculations from runs made at a heating
rate of 5°F/min to a terminal temperature of 1500°F with no holding time. All
tests show good sulfur removal with a range of 0.52% to 0.81% total sulfur in
the coal residue (float or +50 mesh). Total weight loss (pretreatment and
hydrogen treatment) is about 50%. Some of the loss is from the moisture content
of the raw coal, and some losses will be recoverable as useful tars, oils, and
gases from the process.
Two of the runs, TB-53 and TB-54, were made without lime. The residues
were separated by the two methods as indicated in Table 33. This was done to
84
-------
00
Oi
TABLE 31. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temp, °F
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial 1
Treated
Weight LOBS, %
Qt Total Weight
Of Coal Weight
Reduced Data
(100 Ib Original Coal)
Weight, Ib 1
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt %, Original Sulfur
Removed From Feed
Removed From Coal
No lime.
TB-27
Pretreated W. Ky. No. 9
5
900
30
TB-28*
TB-30
TB-31
Pretreated W. Ky. No. 9 Pretreated W. Ky. No. 9
5 5
900 1500
30 0
Pretreated W. Ky. No. 9
5
1500
0
Coal Pretreated Coal
5. 9
33.4
0.00
0.07
2. 30
0.97
3.34
0.8
24.4
0. 14
0. 18
1.40
1.34
3.06
Feed
0.05
0.06
0.47
0.45
1.03
Residue
0. 38
0.06
0.16
0.40
1.00
Feed
0. 14
0.18
1.40
1.34
3.06
Residue
0.68
0.14
0.49
1.13
Z.44 '
Feed
0.05
0.06
0.47
0.45
1.03
Residue
0.46
0.00
0.13
0.21
0.80
Feed
0.05
0.06
0.47
0.45
1.03
Float
0.08
'0.00
0.54
0.12
0.74
Sink
0.63
0.03
0.10
0.07
0.83
4.8760
3. 1496
4.5381
256.62
4. 5595
6.49
19.47
239. 96
85.54
2. 7452
12.70
12.70
74.67
256.62
4.0333
11. 12
33.37
228.08
0.00
0.07
2. 30
0. 97
3. 34
0.00
0.07
2.30
0.97
3.34
0.12
0. 15
1.20
1. 15
2.62
1.40
1.34
2.74
29.6
0.12
0.15
1.20
1. 15
2.62
0.05
0.06
0.47
0.45
1.03
0.91
0.14
0.38
0.96
2.39
0. 55
1.39
1.94
48. 9
59.9
0.12
0.15
1.20
1.15
2.62
1.40
1.34
2.74
29.6
0.51
0.10
0.37
0.84
1.82
0.49
1.13
1.62
53.8
63.8
0.12
0.15
1.20
1.15
2.62
0.05
0.06
0.47
0.45
1.03
1.05
0.00
0.30
0.49
1.84
0.53
0.86
1.39
69.8
76.3
0.12
0.15
1.20
1.15
2.62
0.05
0.06
0.47
0.45
1.03
0.04
0.00
0.30
0.07
0.41
0.54
0.12
0.66
85.9
88.9
B75123026
1.08
0.05
0.17
0.12
1.42
•
-------
TABLE 32. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9 COAL, 900°F)
oo
Run No.
Coal
Heating Rate, ° F/min
Terminal Temperature, ° F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyrittc
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt % , as
Sulfide
Sulfate
Pyrittc
Organic
Total
Pretreatment
W.
Coal
5. 9
33.4
0. 00
0. 07
2. 30
0. 97
3. 34
100. 00
100. 00
0. 00
0. 07
Z. 30
0. 97
3. 34
0. 00
0. 07
2. 30
0. 97
3. 34
Ky. No. 9
750
Pretreated Cr^l
1. 8
32. 3
0. 13
0. 19
2.87
1^29
4. 48
85. 54
14.46
14.46
85. 54
0. 11
0. 16
2.45
1. 10
3.82
2.87
1.29
4. 16
TB-34
TB-42
Pretreated W. Ky. No. 9 Pretreated W. Ky. No. 9
5 5
900 900
30 30
Feed Float Sink Feed +50 —50
0. 04
0. 06
0. 96
0. 43
1.49
4. 2716
0. 11
0. 16
2.45
1. 10
3.82
TB-33
Pretreated W. Ky. No. 9
5
900
30
Feed +50 -50
0. 07 0. 33 0.04
0.00 0.07 0.06
0. 50 0. 29 0. 96
1. 04 0. 17 0.43
1.61 0.86 1.49
1.22 0.27 0.04
0.01 0.04 0.06
0.64 0. 00 0. 96
1. 36 0. 21 0.43
3.23 0.52 1.49
0.86
0.05
1.00
0. 92
2.83
0.22
0.04
0.11
0.09
0.46
4. 5483
4. 1169
0.9279 2.9854
7. 94
23.81
1.1509 2.9930
7.94
23.83
1.0293 2.7387
7.82
23.47
256.62 56.02 180.22 256.62 65.61 170.63 256.62 64.62 171.93
Wt % Original Sulfur Removed
From Feed
0.04
0.00
0. 28
0. 58
0. 90
0. 50
1.04
1. 54
56.6
0. 59
0.13
0. 52
0. 31
1. 55
0. 11
0.16
2.45
1.10
3. 82
0. 80
0.01
0.42
0.89
2. 12
0.64
1. 36
2.00
43.7
0.46
0.07
0.00
0. 36
0.89
0. 11
0.16
2.45
1.10
3.82
0. 56
0.03
0.65
0. 59
1.83
1.00
0.92
1.92
45. 9
0. 38
0.07
0.19
0.15
0.79
B75123046
-------
TABLE 33. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9 COAL, 1500°F)
oo
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sdlfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Pretreatment
TB-35
TB-45
TB-52
W. Kentucky No. 9 Pretreated W. Kentucky No. 9
5
750 1500
0
Pretreated
Coal Coal Feed +50 - 50
Pretreated W. Kentucky No. 9
5
1500
0
Pretreated W. Kentucky No.
5
1500
0
Feed
Float
Sink
Feed
Float
Sink
5.9
33.4
0.0
0.07
2.30
0.97
3.34
1.8
32.3
0.13
0.19
2.87
1.29
4.48
0.04
0.06
0.96
0.43
1.49
0.00
0.02
0.28
0.39
0.69
0.88
0.08
0.15
0.24
1.35
0.04
0.06
0.96
0.43
1.49
0.05
0.01
0.31
0.51
0.88
0.83
0.13
0.11
0.31
1.38
0.04
0.06
0.96
0.43
1.49
0.13
0.00
0.05
0.69
0.87'
1.14
0.09
0.01
0. 10
1.34
100.00
85. 54
14.46
14.46
4.4377
4.4377
0.9085
2.9429
0.8339
3.2445
4. 3962
12.82
38.45
12.54
37.60
0.7817 2.9114
12.89
38.68
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
100.00
0.00
0.07
2.30
0.97
3.34
85.54
0.11
0. 16
2.45
1.10
3782
256.62
0.11
0.16
2.45
1.10
3.82
52.77
0.00
0.01
0.15
0.21
6737
170.95
1.50
0.14
0.26
0.41
2. 31
256. 62
0. 11
0. 16
2.45
1. 10
3. 82
46.42
0.02
0.01
0. 14
0.24
0.41
180.59
1.50
0.23
0.20
0.56
2.49
256.62
0. 11
0. 16
Z.45
1.10
3.82
47. 32
0.06
0.00
0.02
0.33
074T
176.22
2.01
0. 16
0.02
0.18
2. 37
Sulfur Content, wt%, as
Sulfide 0.00
Sulfate 0.07
Pyritic 2. 30
Organic 0.97
Total 3.34
Wt % Original Sulfur Removed
From Feed
2.87
1.29
47T6-
0.28
0. 39
0. 67
81. 1
0.31
0.51
0.82
76.9
0.05
0.69
0.74
90.8
D75123027a
-------
TABLE 33. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9 COAL, 1500°F) (Continued)
oo
oo
Run No.
Coal Type
Heating Rate, "F/min
Terminal Temperature, °F
Holding Time, rnin
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt%, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
*No lime.
TB-53*
Pretreated W. Kentucky No. 9
5
1500
0
TB-54*
Feed
4.7038
85.54
Pretreated W. Kentucky No. 9
5
1500
0
TB-57
Pretreated W. Kentucky No. 9
5
1500
0
TB-58
Pretreated W. Kentucky No. 9
5
1500
0
50
- 50
Feed
Float
Sink
Feed
Float
Sink
Feed
Float
Sink
0.13
0.19
2.87
1.29
4.48
0.44
0.00
0.34
0. 19
0.97
2.00
0.00
0. 18
1.22
3.40
0.13
0.19
2.87
1.29
4.48
0.15
0.00
0.45
0.07
0.67
2.13
0.02
0.10
0.36
2.61
0.04
0.06
0.96
0.43
1.49
0.06
0.02
0.00
0.81
0.89
0.24
0.40
0.06
0.43
1.13
0.04
0.06
0.96
0.43
1.49
0.14
0.00
0.45
0.36
0.95
0.67
0.14
0.01
0.38
1.20
2.611 0.2407
38.29
2.8771
4. 6800
1.4686
0.2936
38.75
4.9088
0.1428 3.8901 0.8846 3.5508
13.83 13.64
48.41
4.38
85.54
43.66
8.73
256.62
7.92 215.78 256.62
44.20 177.42
0.11
0. 16
2.45
«. 10
3.82
0.21
0.00
0. 17
0.09
0~47
0.09
0.00
0.01
0.05
oTTs
0.11
0.16
2.45
1.10
3.82
0.06
0.00
0.20
0.03
0.29
0.19
0.00
0.01
0.03
0.23
0.11
0.16
2.45
1.10
3.82
0.01
0.00
0.00
0.06
0.07
0.52
0.86
0.13
0.93
2.44
0.11
0.16
2.45
1.10
3.82
0.06
0.00
0.20
0.16
0.42
0.19
0.25
0.02
0.67
1.13
0.34
0. 19
0753
93.2
0.00
0.81
WTST
94.0
0.45
0.36
0.81
78.8
D75123027b
-------
determine the amount of treated material that would report to the lime
portion (sink or —50 mesh) in the tests using mixed feed. In TB-53, 8.3%
of the treated coal material remaining was -50 mesh, while 16.7% in'lB-54
was in the sink portion. The treated material splits are assumed to occur in
this way in the tests with lime. Also, the -50 and sink fractions have much
higher sulfide and organic-type sulfur percentages than the +50 or float
portions. This effect could be used in further sulfur reduction.
Run TB-57 was made with the pretreated material ground to -80 mesh and
then mixed, treated, and separated. A disproportionately large portion of the
treated material went to the sink portion of the separated material, making
conclusions difficult.
The other runs (TB-35, TB-45, TB-52, and TB-58) were made with the usual
coal-lime mix. They were screen- or float-separated as shown. Higher weight
loss is experienced in the float-sink technique than in the screen separation,
as illustrated by Runs TB-53 and TB-54. Assuming that the sulf ide and sulf ate
can be removed by chemical or mechanical means, the coal-fraction sulfur con-
tent of these runs ranges from 0.52% to 0.82%. Heating values of 8,667 to
13,667 Btu/lb of treated material would give S02 emissions of 1.20 lb/106 Btu
for these tests. Heating values from the early batch tests (Table 9) are
12,699 to 12,920 Btu/lb. If similar values are assumed for this material,
only the higher sulfur content material would exceed the allowable limits.
The next set of runs, shown in Table 34, are those heated to 1500°F at
5°F/min and then held for 30 minutes at the final temperature. In Runs TB-61
and TB-63, nitrogen was used for initial preheat to 700°F and hydrogen to the
end of the run. Runs TB-62 and TB-63, made with —80 mesh pretreated coal, have
poor coal-fraction recovery. All tests show a lower total sulfur content,
ranging from 0.36% to 0.75%, indicating that the holding time is beneficial.
S0? emission again depends upon the heating value of the recovered coal portion,
but is in the proper range.
Table 35 presents runs that were heated at 5°F/min to 1500°F, with no
holding time, but had various feed or operational changes. Runs TB-59 and
TB-60 were made with —80 mesh pretreated coal only. These tests exhibit a
good final sulfur content (0.50% to 0.55%) indicating that the lime may not be
imperative at elevated temperatures. The float-sink technique was used to
determine how the finely ground material would separate. Losses to the sink
fraction may cause a reevaluation of separation techniques when using lime.
Run TB-64 was made with the usual size coal and mixture, but was heated
to 700°F with nitrogen and then with hydrogen the remainder of the time to the
terminal temperature of 1500°F. The sulfur content of the product is in the
higher end of the range and the separation was poor, indicating 1) this treat-
ment is not beneficial, and 2) some sulfur reacts with the hydrogen at lower
temperatures.
The pretreated coal feed for Run TB-65 was subjected to a 1:7 HNO^ solu-
tion for 1 hour under reflux. These conditions are similar to the ASTH method
for FeS, extraction. Afterward the coal was washed, filtered, dried, ground
to -20+40 mesh, and mixed with lime in the usual ratio for the test. The
89
-------
TABLE 34. THESMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1500°F, 30 min)
100.00
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °]
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight
Sulfide
Sulfate
Pyritic
Organic
Total -
Sulfur Content, wt %, as
Sulfide 0.00
Sulfate 0.07
Pyritic 2. 30
Organic 0.97
Total 3.34
Wt % Original Sulfur Removed
From Feed
Pretreatment
W. Kentucky No. 9
100.00
750
TB-36
Pretreated W. Kentucky No. 9
5
1500
30
TB-37
Coal
•3J4
0.00
0.07
2.30
0.97
3.34
Pretreated
Coal
1.8
32.3
0.13
0.19
2.87
1.29
4.48
Feed
0.04
0.06
0,96
0.43
1.49
Float
0.00
0.06
0.49
0.26
0.81
Sink
0.95
0.05
0.04
0. 32,
T736
85.54
14.46
14.46
85.54
4.6108
0.8837
3.2341
13.30
39.30
256.62
47.45
174.74
0.00
0.07
2.30
0.97
3.34
0.11
0. 16
2.45
1.10
3.82
0.11
0. 16
2.45
1. 10
3.82
0.00
0.03
0.23
0. 13
0.39
1.66
0.09
0.07
0. 56
2. 38
0.49
0.26
0.75
78.9
Pretreated W. Kentucky No. 9
5
1500
30
Feed
4.7242
256.62
0. 11
0. 16
2.45
1.10
3.82
Float
Sink
0.04
0.06
0.96
0.43
1.49
0.04
0.01
0.23
0.32
0.60
0.99
0.06
0.08
0.23
1.36
0.9266
3.1288
14.48
43.44
60.14
0.02
0.01
0. 12
0.16
0.31
169.32
1.68
0.10
0.14
0.39
2.31
84.5
D75123031
-------
TABLE 34. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1500°F, 30 min) (Continued)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight
Sulfide
Sulfate
Pyritic
Organic
Total .
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
*"—80 mesh pretreated coal.
TB-61
TB-62*
TB-63*
Pretreated W. Kentucky No. 9 Pretreated W. Kentucky No. 9
5 5
1500 1500
30 30
Feed
1.49
4.6874
256.62
Pretreated W. Kentucky No. 9
5
1500
30
Float
Sink
Feed
Float
Sink
Feed
Float
Sink
0.04
0.06
0.96
0.43
0.32
0.01
[0. 51}
0.80
0.11
{0. 46}
0.04
0.06
0.96
0.43
0.10
0.00
0.36
0.00
0.78
0. 12
0. 13
0.40
0.04
0.06
0.96
0.43
0.23
0.05
0.00
0.71
0.64
0.14
0. 11
0.40
0.84
1.37
1.49
4.9800
0.46
1.43
0.9437 3.0926
13.89
35.49
51.66 169.31 256.62
0.1563 4.0783
14.97
44.90
8.05 210.15
1.49
4.8231
0.99
1.29
256.62
0. 11
0. 16
2.45
1. 10
0.17
0.01
{0.26}
1.35
0. 19
{0.78}
0.11
0. 16
2.45
1. 10
0.01
0.00
0.03
0.00
1.64
0.25
0.27
0.84
0. 11
0.16
2.45
1. 10
0.02
0.00
0.00
0.05
1.36
0.30
0.23
0.85
3.82
0.04
3.00
3.82
{0. 51}
oTsT
93.2
99.2
0.00
0.71
0.71
98.7
D75123031
-------
TABLE 35. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO.
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Pretreatment TB-59*
W. Kentucky No. 9 Pretreated W. Kentucky No. 9
5
750 1500
0
Pretreated
Coal Coal Feed Float Sink Feed
9, 1500 F, 0 min)
TB-60*
Pretreated W. Kentucky No. 9
5
1500
0
5.9
33.4
0.00
0.07
2. 30
0.97
3.34
1.8
32.3
0. 13
0.19
2.87
1.29
4.48
0. 13
0. 19
2.87
1.29
4.48
0. 19
0.00
0.30
0.24
0.73
0. 54
0.00
0.26
0.28
1.08
0. 13
0.19
2.87
1.29
4.48
Float
0.14
0.00
0.27
0.25
076"6
Sink
vo
Weight, g
Inttial 100.00
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 100.00
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
85.54
14.46
14.46
85.54
2.87
1.29
4.0071
85. 54
1. 4447
30.84
1.004
38.88
0.30
0.24
5754
95. 8
21.44
3.9726
85.54
0.00
0.07
2.30
0.97
3.34
0.11
0.16
2.45
1. 10
3.82
0.11
0.16
2.45
1. 10
3.82
0.06
0.00
0.09
0.07
0.22
0. 12
0.00
0.05
0.06
0.23
0.11
0. 16
2.45
1.10
3.82
1.9371
0.4812
41.88
0.06
0.00
0.11
0.10
0.27
0.27
0.25
0.52
94.5
38.87
10.41
0.09
0.03
0.00
0.05
0.17
*No lime.
-------
TABLE 35. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1500°F, 0 min) (Continued)
vD
CO
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
TB-64
TB-65
TB-66
Pretreated W. Kentucky No. 9
5
1500
0
0.11
0. 16
2.45
1.10
3.82
Pretreated W. Kentucky No.
5
1500
0
Pretreated W. Kentucky No. 9
5
1500
0
Lab Analysis, wt % Feed Float Sink
H20
Volatile Matter
Sulfur, wt %, as
Sulfide O.Q4
Sulfate 0.06
Pyritic 0.96
Organic 0. 43
Total 1.49
Weight, g
Initial 4.8239
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 256.62
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total 3.82 0.34 2.04
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Remove
From Feed 92. 7
Feed
Float
Sink
Feed
Float
Sink
0. 16
0.00
0.37
0.38
0.91
0. 53
0. 16
0.01
0.40
1. 10
0.01
0.02
0. 34
0.52
0.89
0.08
0.00
0.35
0.21
0.64 '
0.21
0.11
0.05
0.20
0. 57
0.00
0.01
0.37
0.65
1.03
0.34
0.03
0.73
0.23
1.33
0.60
0.09
0. 13
0.43
1.25
0.7019 3.4910
13.08
39.24
37.34 185.71
4.4535
256.62
0.5656 3.8879
13.36
40.08
28.24 194.10
4.4777
300.00
0.0414 3.8316
13.50
40.50
2.78 256.72
0.06
0.00
0. 14
0. 14
0.98
0.30
0.02
0.74
0.03
0.05
0. 87
1.33
0.02
0.00
0. 10
0.06
0.41
0.21
0. 10
0. 39
0.00
0.01
0.37
0. 65
0.01
0.00
0.02
0.01
1.54
0.23
0.33
1. 10
2.28
0. 18
0.35
0.21
0756"
95. 8
1. 11
1.03
0.04
0.73
0.23
0.96
97.1
3.20
D75123032
-------
treatment reduced the pyritic sulfur by over 50% and the total sulfur to 2.69%.
After hydrogen treatment, the residue contained 0.56% pyritic plus organic
.sulfur, similar to other tests. Therefore, preremoval of pyrite by standard
washing techniques is not beneficial.
For Run TB-66, the raw coal was treated with IN Fe2(SO^>3 (similar to the
Meyers Process) for 11 hours and then crushed to —80 mesh and mixed with lime.
The results are not conclusive because of the small amount of float material
recovered. The float material did not have sulfur values as low as previous
tests indicating (preliminarily) that utilization of the Meyers Process is not
beneficial as a modification of this process. However, the Fe^^O,)^ treatment
did prevent the agglomeration of the coal and may prove to be a substitute for
air pretreatment.
Table 36 lists tests heated at 10°F/min to 1500°F, with one test being
held for 30 minutes. Weight losses and separation values are consistent with
other tests at this temperature. Residue sulfur contents are slightly higher
with this heat-up rate, compared with tests at the slower heating rate (5°F/
min). The increased coal residence time associated with the slower rate may
have caused the improved sulfur removal. Table 37 presents data at a heat-up
rate of 20°F/min: One test was held for 15 minutes, another was held for 30
minutes, and the rest had no holding time. Weight loss is as expected but the
sulfur content is higher at 0.70% to 0.95%.
A series of tests, Table 38, was heated at 5°F/min to 1300°F; one test
was held for 30 minutes. The results show slightly less weight loss, but the
sulfur content is higher at 0.89% to 1.14%. Because this range is too high,
it was concluded that 1300°F is not an adequate treatment temperature.
One test, TB-41 (Table 39), was heated at 20°F/min to 1600°F and held for
30 minutes. All of the parameters — weight loss, recovery, and final sulfur
content — are no better than similar tests at 1500°F; therefore, it appears
that no benefit is achieved from higher temperature.
The data on final sulfur content from all tests are presented in Figures
31 and 32. Figure 31 presents those tests heated at 5 F/min. Sulfur content
definitely decreases as the temperature increases to 1500°F. No definite
effect is discernible to prove the value of residence time at the final
temperature.
The tests at higher heat-up rates, 10° and 20°F/min, presented in Figure
32, also exhibit a decrease in sulfur content but the decrease is not so great
as in the tests at 5°F/min heat-up rate. Holding the test runs at the terminal
temperature long enough to make the run times equal may depress this line to
the level of the tests on Figure 31.
THERMOBALANCE TESTS - PITTSBURGH SEAM, WEST VIRGINIA
When the Western Kentucky No. 9 coal test series was concluded, a second
coal was selected for a group of tests that would be definitive but not as
exhaustive. Pittsburgh seam coal from a West Virginia mine was selected as an
Eastern coal with a high-sulfur content.
94
-------
TABLE 36. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 10°F/min, 1500 F)
vo
Ui
Run No.
Coal Type
Heating Rate, ° F/min
Terminal Temperature, ° F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, a
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
Pretreatment
W.
Coal
5.9
33.4
0.00
0. 07
2. 30
0. 97
3. 34
100. 00
100. 00
0.00
0. 07
2. 30
0. 97
3. 34
0. 00
0. 07
2. 30
0. 97
3. 34
Ky. No. 9
750
Pretreated Coal
1.8
32. 3
0. 13
0. 19
2. 87
1.29
4.48
85. 54
14.46
14.46
85. 54
0. 11
0. 16
2.45
1. 10
3.82
2. 87
1.29
4.16
TB-44
TB-51
TB-46
Pretreated W. Ky. No. 9
10
1500
0
Feed Float Sink
0.04 0.11 0.84
0.06 0.01 0.06
0. 96 0. 75 0. 11
0.43 0.22 0.19
1.49 1.09 1.20
4. 5669
0.8950 3.1362
12. 56
37.68
256.62 48.51 175.88
0. 11 0.05 1.48
0.16 0.00 0.11
2.45 0.36 0.19
1.10 0.11 0.33
3.82 0.52 2.11
0.75
0.22
0. 97
72.7
Pretreated W. Ky. No. 9
10
1500
0
Feed Float Sink
0.04 0.24 1.04
0.06 0.00 0.09
0.96 0.03 0.00
0.43 0.77 0.17
1.49 1.04 1.30
4.4300
0.9141 3.0170
12.63
37. 90
256.62 52.13 172.08
0.11 0.12 1.79
0.16 0.00 0.15
2.45 0.02 0.00
1.10 0.40 0.29
3.82 0.54 2.23
0.03
0.77
0.80
89.0
Pretreated W. Ky. No. 9
10
1500
30
Feed Float
0.04 0.11
0.06 0.00
0.96 0.76
0.43 0.02
1.49 0.89
4.4200
0.7773
11.
34.
256.62 47.67
0.11 0.05
0.16 0.00
2. 45 0. 36
1.10 0.01
3.82 0.42
0.76
0.02
0.78
78.0
Sink
1.09
0.06
0.11
0. 14
1.40
3.0131
35
05
180. 83
1.97
0. 11
0. 20
0.25
2. 53
B75123075
-------
TABLE 37.
THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 20°F/min, 1500°F)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H;,0
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Pretreatment
TB-43
TB-47
W. Kentucky No. 9 Pretreated W. Kentucky No. 9
20
750 1500
0
Coal
5.9
33.4
0.00
0.07
2. 30
0.97
3.34
Pretreated
Coal
1.8
32.3
0.13
0.19
2.87
1.29
4.48
Feed
0.04
0.06
0.96
0.43
1.49
Float
0.27
0.00
0.84
0.04
1. 15
Sink
0.81
0.08
0.20
0.24
1. 33
Pretreated W. Kentucky No. 9
20
1500
0
Feed
Float
Sink
0.04
0.06
0.96
0.43
1.49
'iQ.28
0.04
0.36
0.54
1.22
0.80
0.14
0.09
0.25
1.28
vo
Weight, g
Initial 100.00
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 100.00
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt%, as
Sulfide 0.00
Sulfate 0.07
Pyritic 2. 30
Organic 0.97
Total 3.34
Wt % Original Sulfur Removed
From Feed
85.54
14.46
14.46
85.54
4.5063
256.62
0.9437
3.0073
12.59
37.77
53. 58
0.84
0.04
0.88
75.2
170.73
0.00
0.07
2.30
0.97
3.34
0.11
0.16
2.45
1.10
3.82
0.11
0.16
2.45
1.10
3.82
0. 14
0.00
0.45
0.02
576T
1.38
0. 14
0.34
0.41
2.27
4.0954
256.62
0.8857
54.39
2.7766
12.37
37.12
0.36
0.54
0.90
74.6
170.49
0.11
0.16
2.45
1.10
3.82
0.15
0.02
0.20
0.29
0. 66
1.36
0.24
0.15
0.43
2.18
-------
TABLE 37. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO.
VO
-J
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
HZO
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt%, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
TB-50
Pretreated W. Kentucky No. 9
20
1500
15
Feed
0.04
0.06
0.96
0.43
1.49
4.1714
256.62
Float
0.36
0.06
0.40
0.47
1.29
Sink
0.96
0.14
0.02
0.22
1.34
0.9013 2.7903
11.95
35.86
62.62 194.00
0.11
0.16
2.45
1. 10
3782
0.23
0.04
0.25
0.29
oTsT
1.86
0.27
0.04
0.43
2760
0. 40
0.47
0.87
85.9
9, 20°F/min, 1500°F) (Continued)
TB-56
Pretreated W. Kentucky No. 9
20
1500
0
Feed
0.04
0.06
0.96
0.43
1.49
3.7436
256.62
Float Sink
0.25
0.00
0.04
0.72
1.01
0. 30
0.08
0.00
0. 32
0.70
0.9515
2.3225
12.78
38.33
65.05
158.77
0.11
0. 16
2.45
1. 10
3.82
0. 16
0.00
0.03
0.47
0756
0.47
0. 13
0.00
0.51
T7TT
86.91
-------
TABLE 37. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 20°F/min, 1500°F) (Continued)
VO
00
Run No.
Coal Type
Heating Rate, "F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt%, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
TB-55
TB-40
Pretreated W. Kentucky No. 9 Pretreated W. Kentucky No. 9
20 20
1500 1500
0 0
Feed
4.5487
256.62
Float
Sink
Feed
Float
Sink
0.04
0.06
0.96
0.43
1.49
0.22
0.00
0. 56
0.39
1. 17
0.69
0.07
0.00
0.33
1.09
0.04
0.06
0.96
0.43
1.49
0. 34
0.00
0.33
0.37
1.04
1. 18
0.05
0.03
0.28
1.54
4.5438
0.7746 2.4618
10.30
30.89
55. 11
175.18 256.62
1.0533 3.0353
13.27
39.81
57.34 165.23
0. 11
0. 16
2.45
1. 10
3.82
0. 12
0.00
0.31
0.21
0.64
1.18
0.12
0.00
0.56
1.86
0.11
0. 16
2.45
1. 10
3.82
0. 19
0.00
0. 19
0.22
0.60
1.95
0.08
0.05
0.46
2.54
0.56
0. 39
0.95
86. 4
0.33
0. 37
0.70
80. 3
D75123021
-------
TABLE 38. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1300 F)
v£>
W. Kentucky No. 9
750
Coal Pretreated Coal
Run No. Pretreatment
Coal
Heating Rate, °F/min
Terminal Temperature, ° I
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial 100.00
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib 100. 00
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
s Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
TB-39
TB-38
Pretreated W. Ky. No. 9
5
1300
0
Feed +50 -50
Pretreated W. Ky. No. 9
5
1300
0
Feed Float Sink
5.9
33.4
0. 00
0. 07
2. 30
0. 97
3. 34
1
. 8
32. 3
0.
0.
2.
1.
4.
13
19
87
29
48
0.
0.
0.
0.
1.
04
06
96
43
49
0. 30
0.00
0. 53
0.47
1.30
0.
0.
0.
0.
1.
69
10
00
47
26
0.
0.
0.
0.
1.
04
06
96
43
49
0. 00
0. 00
0. 88
0. 24
1. 12
0.62
0. 08
0.02
0.42
1. 14
85. 54
14.46
14.46
85. 54
4.4626 4.6853
0. 9832 2. 9246
11.68
35. 03
256.62 57.02 169.63 256.62
0.9805 3.2105
12. 19
36.56
52.72 172.62
0.00
0. 07
2. 30
0. 97
3. 34
0. 00
0. 07
2. 30
0. 97
3. 34
0.
0.
2.
1.
3.
2.
4.
11
16
45
10
82
87
12
16
0.
0.
2.
1.
3.
11
16
45
10
82
0.17
0. 00
0. 30
0. 27
0.74
0. 53
0.47
1. 00
1.
0.
0.
0.
2.
17
17
00
80
14
0.
0.
2.
1.
3.
11
16
45
10
82
0.00
0. 00
0.46
0. 13
0. 59
0. 88
0.24
1. 12
1.07
0. 14
0.03
0. 73
1.97
71.8
68.5
-------
TABLE 38. THERMOBALANCE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1300°F) (Continued)
O
O
Run No.
Coal
Heating Rate, ° F/min
Terminal Temperature, ° F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
s Sulfide
Sulfate
Pyritic
TB-48
TB-49
Total
Wt % Original Sulfur Removed
From Feed
Pretreated W. Ky. No. 9
5
1300
0
Feed Float Sink
0.04 0.20 0.91
0.06 0.00 0.05
0.96 0.56 0.13
0.43 0.33 0.12
1.49 1.09 1.21
4. 3008
0.8317 2.9358
12. 30
36. 91
256.62 49.69 175.36
0.11 0.10 1.60
0.16 0.00 0.09
2.45 0.28 0.23
1.10 0.16 0.21
3.82 0.54 2.13
0. 56
0.33
0.89
88. 5
Pretreated W. Ky.
Feed
0.04
0.06
0. 96
0.43
1.49
4. 1520
256.62
0.11
0.16
Z. 45
1.10
3.82
5
1300
30
Float
0.24
0.00
0. 56
0. 58
1.38
0. 8177
11.
35.
50. 37
0. 12
0.00
0. 28
0. 29
0.69
0.56
0.58
1.14
85.1
No. 9
Sink
0.61
0.12
0.06
0.31
1.10
2. 8498
98
95
- 1.07
0.21
0.11
0. 54
1.93
B75123074
-------
TABLE 39. THERMOBALANGE RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1600°F)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °:
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally) 100. 00
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
Pretreatment
TB-41
Western Kentucky No. 9
7min
Coal
5.9
33.4
0.00
0. 07
2. 30
0. 97
3. 34
100. 00
100. 00
0.00
0. 07
2. 30
0. 97
3.34
s
0. 00
0.07
2. 30
0. 97
3.34
750
Pretreated Coal
1.8
32. 3
0. 13
0. 19
2. 87
1.29
4.48
85. 54
14.46
14.46
85. 54
0. 11
0. 16
2.45
1. 10
3.82
2.87
1.29
4. 16
Pretreated
Western Kentucky No. 9
20
1600
30
Feed Float
0.04 0.37
0.06 0.00
0.96 0.11
0.43 0.54
1.49 1.02
3.6476
0.6887
14
43
256.62 48.00
0.11 0.18
0. 16 0. 00
2.45 0.05
1.10 0.26
3.82 0.49
0.11
0. 54
0.65
Sink
,
1.38
0.03
0.02
0.18
1.61
2.4628
.40
.19
171.67
2.37
0.05
0.03
0.31
2.76
81.7
A75123022
101
-------
UJ
cr
u.
6.0
5.0
4.0
3.0
2.0
1.0
A FLOAT, NO HOLD
V FLOAT, 30-MIN. HOLD
D +50, NO HOLD
O +50, 30-MIN. HOLD
O PRETREATED COAL
600 800 1000 1200 1400
TEMPERATURE, F°
1600
A75I22920
1800
Figure 31. Thermobalance char-sulfur content at 5 F/min heating rate.
-------
UJ
H-
O
O
CC
ID
5.0
4.0
3.0
2.0
1.0
0
O
D
V
O
I
FLOAT,20°F/min,30-min HOLD
FLOAT, IO°F/m in, 30-min HOLD
FLOAT, 20°F/min , NO HOLD
PRETREATED COAL
I
I
I
600 800 1000 1200 1400
TEMPERATURE, °F
1600 I8OO
A7707I722
Figure 32. Thermobalance char-sulfur content at 10 and 20 F/min
heating rates.
-------
A quantity of the coal was pretreated in the same way as the Western
Kentucky No. 9. Results of the pretreatment and Run TB-67 are presented in
Table 40. Weight losses are in the range expected (10% to 15%). The sulfur
content of the treated coal was also low, comparable to the treated Midwestern
coal. However, the feedstock was not pretreated adequately (compared with the
Western Kentucky coal treated at the same condition) and the sample caked in
the thermobalance test. Therefore, the sulfur content is not indicative of
values that might be experienced if the coal were properly pretreated.
The pretreated material was subjected to a second air treatment, and
thermobalance runs were made. The second pretreatment reduced the volatile
content, but the coal still caked in all thermobalance tests. These data
indicate that this sample of Pittsburgh seam coal is more agglomerating than
the Western Kentucky coal.
Runs TB-68 to TB-70, in Table 41, were made with the double pretreated
coal. All these tests were heated at 5°F/min to 1500°F. Run TB-69 had a 30-
minute holding time and nitrogen was used for the initial heat-up to 700°F
and then hydrogen to the run's end at 1500°F. The coal used for Run TB-70 was
ground to —80 mesh before mixing. Sulfur reduction is good in Runs TB-68 and
TB-69 despite the caking. The low recovery and high-sulfur content of the
residue in Run TB-70 make obtaining the fine material unfeasible with these
operating conditions.
A new sample of raw coal was screened and severely pretreated. The coal
was heated to 750°F with air and held at this temperature for 1 hour. Weight
loss, including moisture, was over 18%. The volatile matter content was re-
duced to about 25% in the final material. This degree of pretreatment was
sufficient because the treated coal did not cake in subsequent testing.
Thermobalance test Runs TB-71 and TB-75, Table 42, were made with this
pretreated coal. Both were heated at 5°F/min to 1500°F with no holding. Run
TB-71 was mixed with lime in the usual ratio; TB-75 used coal only. This coal,
however, does not separate into float-sink portions as readily as the Western
Kentucky No. 9; more of the coal goes into the sink portion. The sulfur con-
tent of the treated coal has been reduced near to the levels expected at these
conditions based on past experience with Western Kentucky coal.
The pretreatment for the above tests was severe. To determine if less
treatment would have sufficed, some coal was pretreated at less severe con-
ditions — shorter time at 750 F.
The pretreated material was then used for Runs TB-72 to TB-74, presented
in Table 43. Runs TB-73 and TB-74 were heated at 5°F/min to 1500°F with no
holding. Run TB-73 was mixed with lime, while TB-74 was coal only. Both
residues showed slight agglomeration, making the separation difficult. The
sulfur was significantly reduced in both tests. Apparently, the lime is
desirable because Run TB-74 shows a higher sulfur content; these results may,
however, be masked by poorer separation.
In Run TB-72, a rapid heat-up procedure was used. The reactor was heated
to 1500°F and the basket was lowered into the heated zone. A large temperature
104
-------
TABLE 40. THERMOBALANCE RUN DATA (PRETREATED PITTSBURGH
SEAM, W. VA., 1500°F, 0 min)
Run No.
Pretreatment
TB-67
Coal Type Pittsburgh Seam, W. Va. Pretreated Pittsburgh
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt °'o
H2O
Volatile Matter
Sulfur, wt °~o, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, <%
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt #>, as
Sulfide
Sulfate
Pyritic
Organic
Total
Coal
7. 7
33. 8
0. 00
0. 05
1. 4Q
1. ?7
2. 91
100. 00
100. 00
0. 00
0. 05
1.49
1 37
2. 91
0. 00
0. 05
1.49
1. 37
2.91
Wt <, Original Sulfur Removed
From Feed
Wt "a Original Sulfur Removed
From Original Coal
750
Pretreated Coal Feed
1. 2
•»3. 0
0. OP 0.03
0. 10 0. 03
1.24 0.41
1.42 0.47
2.85 0.94
4. 7900
85.64
14. 36
14. 36
85.64 256.92
0.08 0.08
0.08 0.08
1.05 1.05
1.20 1.20
2.41 2.41
1.24
1.42
2.66
22.68
5
1500
0
Float
--
--
0. 29
0. 06
0. 02
0.45
0. 82
1.2970
13.
41.
69. 57
0. 20
0.04
0.01
0. 31
0. 56
0.02
0.45
0.47
86.7
89.0
1
Seam, W. Va.
Sink
--
--
0.42
0. 12
0. 00
0. 16
0.70
2.8236
97
92
151.46
0.64
0.18
0.00
0.24
1.06
5-114-2072
105
-------
TABLE 41. THERMOBALANCE RUN DATA (DOUBLE PRETREATED PITTSBURGH
SEAM, W. VA., 1500°F)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt fo, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Wt, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt ^o Original Sulfur Removed
From Feed
Wt % Original Sulfur Removed
From Original Coal
*—80 mesh.
Double Pretreatment
TB-68
Pittsburgh Seam, W. Va.
750
Coal Pretreated Coal
100. 00
83. 92
Pretreated Pittsburgh Seam, W. Va.
5
1500
0
Feed Float Sink
7.7
33.8
0.
0.
1.
1.
2.
00
05
49
37
91
1
. 1
--
--
--
32.0
0.
0.
1.
1.
3.
10
12
37
41
00
0.
0.
0.
0.
1.
03
04
46
47
00
0.
0.
0.
0.
0.
21
04
02
53
80
0.
0.
0.
0.
0.
42
07
01
09
59
5.0814
1.2166
3.1563
t3. 94
41. 83
251.76
60. 28
156. 38
0.00
0. 05
1.49
1.37
2.91
0.00
0.05
1.49
1.37
2.91
0. 08
0. 10
1. 15
1.18
2. 51
0. 10
0.12
1.37
1.41
3.00
0.08 0.13
0.10 0.02
1.15 0.01
1.18 0.32
2.51 0.48
0.02
0.53
0.55
86.9
88.7
0.66
0.11
0.02
0.14
0. 92
106
-------
TABLE 41. THEKMOBALANCE RUN DATA (DOUBLE PRETREATED PITTSBURGH
SEAM, W. VA., 150Q°F) (Continued)
Run No.
Coal Type
Heating Rate, ?F/min
Terminal Temperature, °F
Holding Time, rnin
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Wt, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt ^ Original Sulfur Removed
From Feed
Wt % Original Sulfur Removed
From Original Coal
*—80 mesh.
TB-69
•Pretreated Pittsburgh Seam. W. Va.
5
1500
30
Feed Float Sink
0.03
0.04
0.46
0.47
1.00
0.30
0.00
0.02
0. 52
0.84
0.60
0.03
0.00
0.16
0. 79
4.9956
251. 76
0.08
0.10
1.15
1.18
2.51
0.9817
3.3146
14.00 .
42.00
50.49
0. 15
0.00
0.01
0.26
0.42
0.02
0. 52
0.54
89.3
90.7
170.46
1.02
0.05
0.00
0.27
1.34
107
-------
TABLE 41. THERMOBALANCE RUN DATA (DOUBLE PRETREATED PITTSBURGH
SEAM, W. VA., 1500°F) (Continued)
Run No. TB-70
Coal Type
Heating Rate, ?F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur^ wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Wt, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt °fo Original Sulfur Removed
From Feed
Wt % Original Sulfur Removed
From Original Coal
#—80 mesh.
Pretreated Pittsburgh Searn^ W. Va. *
5
1510
0
Feed
0.03
0.04
0.46
0.47
1.10
4.7065
251.76
0.08
0.10
1.15
1..18
2. 51
Float
0.00
0. 28
0.03
1.40
1.71
Sink
0.36
0.08
0.01
0.30
0.75
0.1079 3.8968
14. 91
44.73
5.77 245.99
0.00
0.02
0.00
0.08
0.10
0.03
1.40
1.43
0.88
0.20
0.02
0.74
1.84
96.8
97. 3
B-114-2071
108
-------
TABLE 42. THERMOBALANCE RUN DATA (PRETREATED PITTSBURGH SEAM, W. VA., 1500 F, 0 min)
Run No.
Coal Type
Heating Rate, ?F/rmn
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt "<,
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, °t.
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt.%, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt "t Original Sulfur Removed
From Feed
Wt % Original Sulfur Removed
From Original Coal
*No lime.
Pretreatment
Pittsburgh seam.W. Va.
750
Coal Pretreated Coal
7.7 1.0
33. 8 24. 8
0.00 0.16
0.05 0.46
1.49 0.95
1.37 '.66
2.91 3.23
100.00
81.81
18. 19
18. 19
100.00 81.81
0.00 0.13
0.05 0.38
1.49 0.78
1.37 1.36
2.91 2.65
--
--
0. 95
1.66
2.61
26.46
26.46
TB-71
Pretreated Pittsburgh seam,W. Va.
5
1500
0
Feed Float Sink
0.05
0. 15
0. 32
0. 55
1.07
5. 0400
245.43
0. 13
0. 38
0.78
1.36
2.65
0. Z3
0.00
0.01
0.65
0.89
0.6271
30. 54
0.07
0.00
0.00
0. 20
0. 27
0.01
0.65
0.66
92.45
93. 13
0.46
0. 10
0.01
0. 27
0.84
3.7766
12.63-
37.89 •
0.85
0. 18
0.02
0. 50
1. 55
TB-75*
Pretreated Pittsburgh Seam, W. Va.
5
1500
0
Feed Float Sink
0. 16
0.46
0.95
1.66
3.23
2.7784
183.89 81.81
0. 13
0.38
0.78
1.36
2.65
0.57
0.04
0.03
0.72
1.36
42.83
0.24
0.02
0.01
0.31
0.58
0.03
0.72
0.75
87.92
89.00
3.73
0.07
0.04
0.46
4.30
27.49
16.48
0.61
0.01
0.01
0.08
0.71
B75123017
-------
TABLE 43. THERMOBALANCE RUN DATA (PRETREATED PITTSBURGH SEAM, W. VA.)
1XU.11 1NO.
Pre treatment
TB-7Z
Coal Type Pittsburgh Seam, W. Va. Pretreated Pittsburgh Seam, W. Va.
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt °'a Coal
H20 7.7
Volatile Matter 33. 8
Sulfur, wt ",, as
Sulfide 0.00
Sulfate 0.05
Pyritic 1 . 49
Organic 1.37
Total 2.91
Weight, g
Initial 100.00
Treated
Weight Loss, »*»
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib 100. 00
Sulfur Weight, Ib, as
Sulfide 0.00
Sulfate o.05
Pyritic j 49
Organic j. 37
Total 2.91
Sulfur Content, wt ""a, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt "", Original Sulfur Removed
From Feed
Wt "i Original Sulfur Removed
From Original Coal
750
Pretreated Coal Feed
0. 6
31. 6
0.04 0.01
0.10 0.03
1.27 0.42
1. 56 0. 52
2.97 0.98
4. 5112
88. 80
11. 20
11.20
88.80 266.40
0.04 0.04
0.09 0.09
1.13 1.13
1.39 1.39
2.65 2.65
1.27
1. 56
2. 83
13.40
13.40
Rapid
1500
60
Float Sink
0.62 0.65
0.00 0.00
0.01
0. 35 0. 18
0.84
3. 8209
15. 30
45.90
9.10 216.54
0.06 1.41
0.00 0.00
0.02
0.03 0.39
1.8E
No lime.
110
-------
TABLE 43. THERMOBALANCE RUN DATA (PRETREATED PITTSBURGH SEAM, W. VA.) (Continued)
1VU11 1NU.
Coal Type
Heating Rate. °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt °'a
H20
Volatile Matter
Sulfur, wt ",, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, "<,
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt #,, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt "*, Original Sulfur Remove'!
From Feed
Wt <*o Original Sulfur Removed
From Original Coal
No lime.
TB-73
TB-74
Pretreated Pittsburgh Seam, W. Va.
5
1500
0
Feed Float Sink
4.7455
266. 40
Pretreated Pittsburgh Seam, W. Va,
5
1500
0
Feed Float Sink
0.01
0.03
0.42
0. 52
0.98
0. 32
0.02
0. 00
0. 51
0. 85
0. 48
0.05
0.01
0.09
0. 63
0.04
0. 10
1.27
1.56
Z.97
0. 15
0.01
0.03
0. 89
1.08
0. 80
0.06
0.06
0.70
1.62
3. 5142
4. 0378
14.91
44.74
80.48
146.20
88. 80
0.00
0.51
0.51
84. 53
85.91
2.3601
32.84
32. 81
26.83
0.04
0.09
1. 13
1 39
2.65
0.26
0.02
0.00
0.41
0.69
0.70
0.07
0.01
0. 13
0.91
0.04
0.09
1. 13
1. 39
2.65
0.05
0.00
0.01
0.29
0. 35
0.21
0.02
0.02
0. 19
0.44
0.03
0.89
0.92
88.68
89.68
B75020186
111
-------
gradient was imposed and a rapid heat-up was achieved. The sample was left
for 1 hour and then removed. These conditions proved to be too rapid in
heat-up and the sample was badly agglomerated. Complete analysis of the data
was impossible.
Satisfactory sulfur content can be achieved by treatment of this coal;
however, not enough data have been obtained to draw definitive conclusions as
to sulfur removal. Pretreatment must be with longer residence and/or more
air than with the Midwestern coals, resulting in higher weight loss in
pretreatment.
The degree, or severity, of pretreatment differs for each coal. Some coals
require only slight pretreatment and have relatively low weight loss. Others
require more treatment and have higher weight loss.
The Western Kentucky No. 9 coal could be pretreated at 750°F with 1 SCF
02/lb of coal being consumed in 30 minutes. This is representative of the
conditions necessary for pretreatment of coals from the Illinois Basin and
results in about 10% weight loss. Coals such as the Pittsburgh seam require
750°F temperature with 2 SCF 02/lb of coal and from 30 minutes to 1 hour
residence time. Weight loss for this treatment is usually 15% or more.
Each seam or mine may have its own characteristics such that pretreatment
conditions are different for each.
BATCH REACTOR TESTS - WESTERN KENTUCKY NO. 9
The modified batch reactor described earlier was used to test the desul-
furization concept in a fluidized-bed reactor. Information was taken from
thermobalance runs to aid in establishing operating conditions for the unit.
The fluidized-bed arrangement was expected to enhance gas-particle contact
and increase sulfur removal. The feed coal, whether pretreated or not, was
screened to —20+40 mesh and, when mixed, was 2 parts coal to 1 part lime of
—60+80 mesh.
The first tests in the batch reactor were with nonpretreated Western
Kentucky No. 9 coal. Table 44 lists the results of these tests. The heating
rate was 5°F/min to 900°F, except Run BR-74-3 was heated to 1350°F. All tests
were held at their terminal temperatures for 30 minutes. A high hydrogen rate
was used to simulate the gas flow conditions used in the pilot-unit. This
flow was too high for the smaller unit, and excessive bed elutriation resulted.
Some sulfur reduction in the residue took place, but this may be the result of
concentrating the lime portion by flushing out the higher-sulfur-bearing coal
fraction.
Later batch reactor runs were made with pretreated Western Kentucky No. 9
coal. To reduce entrainment losses, the hydrogen flow rate was reduced to
yield a bed velocity of 0.35 ft/s at 900°F and 0.5 ft/s at 1500°F.
Runs BR-74-4 and BR-74-5, in Table 45, were made with the usual mixture
of feedstock materials. Both tests were heated to 900°F at 5°F/min and held
112
-------
TABLE 44. BATCH REACTOR RUN DATA (WESTERN KENTUCKY NO. 9)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, '
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Coal
W.Ky. No. 9
Coal
5.9
33.4
0.00
0.07
2.30
0.97
3.34
BR-74-1
W. Kentucky No. 9
5
900
30
Feed Residue
0.00 0.77
0.07 0.11
2.30 1.69
0.97 1.04
3.34 3.61
BR-74-2
BR-74-3
100.00
100.00
0.00
0.07
2.30
0.97
3.34
0.00
0.07
Z. 30
0.97
3.34
200.00
158.00
21.00
21.00
100.00 79.00
0.00
0.07
2.30
0. 97
3. 34
0.00
0. 07
2. 30
0.97
3. 34
0.61
0.09
1. 34
0. 82
2. 86
1.69
1.04
2.73
W. Kentucky No. 9
5
900
30
Feed Residue
0. 40
0.04
0. 16
0. 16
0.76
167.00
16.50
49. 50
300.00 250.50
0.00
0.02
0.77
0.32
1. 11
200.00
0.00
0.07
2.30
0.97
3. 34
0.00
0.07
2. 30
0.97
3.34
1.00
0. 10
0.40
0. 40
1.90
0.79
0.79
1.58
W. Kentucky No. 9
5
1350
30
Feed
0.00
0.02
0.77
0.32
1.11
200.00
300.00
0,00
0. 07
2. 30
0.97
3. 34
0.00
0. 07
2. 30
0.97
3. 34
Residue
0. 17
0.04
0.08
0.13
0. 42
110.00
45.00
165.00
0.28
0. 07
0. 13
0.21
0. 69
Wt % Original Sulfur Removed
From Feed
From Original Coal
35.3
35.3
76.0
76.0
A75123024
-------
TABLE 45. BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 900°F)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial 100.00
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib 100.00
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
Pretreatment
BR-74-4
BR-74-5
W. Kentucky No. 9 Pretreated W. Kentucky No. 9 Pretreated W. Kentucky No. 9
5 5
750 900 900
30 30
Pretreated
Coal Coal Feed +50 - 50 Feed Residue
5.9
33.4
0.00
0.07
2.30
0.97
3.34
1. »
3Z.3
0.13
0.19
2.87
1.29
4.48
0.04
0.06
0.96
0.43
1.49
0.80
0.07
0.36
1.06
2.29
0.49
0.03
0.19
0.03
0.74
0.13
0. 19
2.87
1.29
4.48
0.86
0.06
0.49
1.17
2.58
85.54
14.46
14.46
85.54
150.00
100.00
38.00
97.00
10.00
30.00
256,62
65.01
165.95
0.00
0.07
2.30
0.97
3.34
0.11
0.16
2.45
1.10
3.82
0. 11
0. 16
2,45
1.10
3.82
0.52
0.05
0.23
0.69
1.49
0.81
0.05
0.32
0.05
1.23
0.00
0.07
2.30
0.97
3.34
2.87
1.29
4.16
0. 11
0.16
2.45
1.10
3.82
0.36
1.06
1.42
85.54
0.11
0.16
2.45
1.10
3.82
0.11
0.16
2.45
1.10
3.82
75.9
85.00
15.00
15.00
72.71
0.63
0.04
0.36
0.85
1.88
0.49
1.17
1.66
68.3
A75123023
-------
for 30 minutes at the terminal temperature. Sulfur reduction was similar to
the thermobalance tests at these conditions.
i-H ^ P^8Sf tS run* hfted at 5°F/mln to 1500°F, with only Run BR-74-10
being held 30 minutes at the final temperature. The treated samples from Runs
BR-74-9 and BR-74-10 were riffled into two parts, and then each part was
screened or float-sink separated. The treated coal fractions show sulfur levels
slightly higher than those from the thermobalance tests at this temperature
Weight losses from the batch reactor runs are higher, but the increased loss
was probably caused by fluidization losses.
A lower terminal temperature, 1300°F, was used in Runs BR-74-8 and BR-74-
11, shown in Table 47. Both tests were heated at 5°F/min, and Run BR-74-11
was held for 30 minutes at 1300°F. High material losses made the results from
Run BR-74-8 inconclusive; however, Run BR-74-11 shows the percentage sulfur
removal in the higher end of the range of values experienced in the 1500°F
tests.
Q Table 48 lists data for Runs BR-74-12 and BR-74-13, heated to 1500°F at
10 and 20°F/min. No holding time was used in either test. The sulfur values
are comparable to the batch reactor tests heated at 5°F/min with no holding,
but are still higher than the thermobalance tests at the same condition.
Further sulfur reduction may be possible by holding at the terminal temperature
after using the higher heat-up rates.
Two runs, BR-74-18 and BR-74-19 (coal only), were exposed to a rapid heat-
up to 1500°F, with Run BR-74-19 being held for 30 minutes (Table 49). The
rapid heat-up is accomplished by turning full power to the heaters until the
target temperature is reached. A rate of 65° to 70°F/min is possible by this
procedure. Weight losses are lower than those usually found at 1500°F because
of the shorter reaction time. Run BR-74-19 has the highest weight loss and
lowest sulfur content as expected. Although the sulfur reduction has not been
reduced to levels usually associated with these temperatures at lower heating
rates, the data are promising. Run BR-74-19, held at 1500°F for 30 minutes,
shows considerably lower sulfur content than Run BR-74-18. This indicates that
rapid heat-up with much longer holding times may be as beneficial as lower
heat -up rates.
The results of the batch reactor tests using pretreated Western Kentucky
No. 9 coal are presented graphically in Figure 33. Total sulfur has been
reduced significantly from the pretreated coal to the hydrogen-treated coal.
Removal of sulfide and sulfate further depress the curve. The differences
between 1300° and 1500°F are less than in the thermobalance tests and are
probably due to better contact between gas and particles. Comparing Figure 33
with Figure 31, the overall sulfur level at 1500°F treatment is not as satis-
factory in the batch reactor tests. Perhaps the much higher relative hydrogen
flows in the thermobalance tend to release the "fixed" organic sulfur.
BATCH REACTOR TESTS - PITTSBURGH SEAM, WEST VIRGINIA
Four runs, BR-74-14 to BR-74-17, shown in Table 50, were made with
Pittsburgh seam coal. Caking was evident in all of these tests, indicating
115
-------
TABLE 46. BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1500 F)
Run No.
Coal Type
Heating Rate, "F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
HZO
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial 150.00
Treated
Weight Loss %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 100.00
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
Pretreatment
W. Kentucky No. 9
750
BR-74-6
3.34
0.00
0.07
2.30
0^97
3.34
Pretreated W. Kentucky No. 9
1500
0
BR-74-7
Pretreated W. Kentucky No. 9
5
1500
0
Pretreated
Coal Coal
5.9
33.4
0.00
0.07
2. 30
0.97
3.34
1.8
32.3
0.13
0.19
2.87
1.29
4.48
Feed
0.04
0.06
0.96
0.43
1.49
+ 50
0.22
0.03
0.40
0.04
0.69
- 50
0.88
0.09
0. 14
0.04
1.15
Feed
0.04
0.06
0.96
0.43
1.49
Float
0.09
0.00
0.68
0.14
0.91
Sink
0.77
0.19
0.02
0.38
1.36
85.54
14.46
14.46
85.54
3.82
150.00
27. 50
96.00
150.00
17.67
53.00
256.62
47.05
164.20
256.62
3.82
0.32
0.40
0^04
0.44
94. 5
1.89
3.82
22:04
96,86
20.73
62.20
37.71
165.71
0.00
0.07
2.30
0.97
0.11
0.16
2.45
1.10
0.11
0.16
2.45
1.10
0. 10
0.01
0. 19
0.02
1.44
0. 15
0.23
0.07
0.11
0. 16
2.45
1.10
0.03
0.00
0.26
0.05
0.75
0.18
0.02
0.37
0.34
0.68
0.14
0.82
91.88
1.32
-------
TABLE 46. BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1500°F) (Continued)
Feed
1.49
150.00
Run No.
Coal Type
Heating Rate, "F/min
Terminal Temperature, "I
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt «!» Original Sulfur Removed
From Feed
Z56. 62
BR-74-9
Pretreated W. Kentucky No. 9
5
1500
0
BR-74-10
Pretreated W. Kentucky No. 9
5
1500
30
Float
Sink
50
- 50
Feed
Float
Sink
+ 50
0.91
1.44
0.92
'1.74
1.49
150.00
0.83
1.47
0.83
f
••-11. -1 -1 •
93.99 . ,
14.73
47.44 128.78
38.56 137.66
256.62
51.39 167.38
0.31
0.48
0.79
90.0
0.51
0.20
0.71
92.7
0. 52
0. 15
0.67
90. 80
- 50
0.04
0.06
0.96
0.43
0. 12
0.00
0.31
0.48
0.74
0. 19
0.05
0.46
0.20
0.01
0.51
0.20
1.18
0.10
0.05
0.41
0.04
0.06
0.96
0.43
0.14
0.02
0. 52
0. 15
1.02
0. 12
0.02
0.31
0.21
0.00
0.39
0.23
1. 34
0.09
0.02
0. 31
1.76
59.25 159.52
0. 11
0.16
2.45
1.10
3.82
0.06
0.00
0. 15
0.23
0.44
0.95
0.24
0.06
0. 59
1. 84
0.08
0.00
0.20
0.08
0.36
1.62
0. 14
0.07
0.56
2.39
0. 11
0. 16
2.45
1. 10
3.82
0.07
0. 01
0.27
0.08
'.43
1.71
0.20
0.03
0. 52
2.46
0. 12
0.00
0.23
0. 14
0.49
2. 14
0. 14
0.03
0.49
2. 80
0. 39
0.23
OT6T
90. 31
D75123030
-------
TABLE 47. BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 1300°F)
00
Pretreatment
W. Kentucky No. 9
750
P retreated
Coal
33.' 4
0.00
0.07
2.30
0.97
3.34
Coal
0.13
0. 19
2.87
1.29
4.48
Feed
0.04
0.06
0.96
0.43
1.49
+ 50
0. 18
0.01
0. 34
0. 51
1.04
- 50
1.01
0.10
0.00
0.42
1.53
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial 100.00 150.00
Treated 85.54
Weight Loss, %
Of Total Weight 14.46 «-
Of Coal Weight 14.46 <-
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 100.00 85.54 256.62
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total 3. 34 3.82 3.82
Sulfur Content, wt %, as
Sulfide 0.00 0.11
Sulfate 0.07 0.16
Pyritic 2.30 2.87 2.45
Organic 0.97 1.29 1.10
Total 3.34 4.16 3.82
Wt % Original Sulfur Removed
From Feed
BR-74-8
Pretreated W. Kentucky No. 9
5
1300
0
Float
43.39
0.45
0.34
0.51
0.85
90. 3
-33.00-
-99.00
128.53
0.00
0.07
2.30
0.97
0.11
0.16
2.45
1.10
0.11
0.16
2.45
1.10
0.08
0.00
0.15
0.22
1.30
0.13
0.00
0.54
42.47
1.97
Sink
0.73
0.08
0.04
0.39
1.24
129.46
88.5
-------
TABLE 47. BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9,
1300°F)
(Continued)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
BR-74-11
Feed
150.00
256.62
0.11
0.16
2.45
1.10
3.82
0.11
0.16
2.45
1.10
3.82
Pretreated W. Kentucky No. 9
5
1300
30
+ 50
52.00
0.44
0.33
0.77
89.5
- 50
Float
168.02
48.80
0.62
0.25
0.87
89.0
Sink
0.23
0.02
0.44
0.33
1.02
0.94
0.13
0.04
0.52
1763
0.12
0.02
0.62
0.25
1.01
0.64
0.23
0.04
0.50
1.41
t
42.78
-">
171.22
0.12
0.01
0.23
0.17
0.53
1.58
0.22
0.07
0.87
2.74
0.06
0.01
0.30
0.12
0.49
1.10
0.39
0.07
0.86
2.42
B75123029
-------
TABLE 48. BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 10° and 20°F/min)
S3
o
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature,
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial 100.00
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib 100.00
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide 0.00
Sulfate 0.07
Pyritic 2. 30
Organic 0.97
Total 3. 34
Wt % Original Sulfur Removed
From Feed
Pretreatment
W. Kentucky No. 9
750
BR-74-12
Pretreated W. Kentucky No. 9
10
1500
- 0
Pretreated
Coal
5.9
33.4
0.00
0.07
2.30
0.97
3. 34
Coal
1.8
32.3
0.15
0.19
2.87
1.29
4.48
Feed
0.04
0.06
0.96
0.43
1.49
+ 50
0.23
0.01
0.43
0.32
0.99
- 50
1.06
0.04
0.01
0.34
1.45
Float
0. 11
0.03
0.40
0.31
0.85
Sink
0. 54
0.21
0.05
0.49
1.29
85.54
14.46
14.46
85.54
150.00
•18.47
•55.42
256.62
59.78
149.44
45.61
88.2
0.40
0.31
0.71
91.6
163.61
0.00
0.07
2. 30
0.97
3. 34
0. 11
0. 16
2.45
1. 10
3.82
0.11
0. 16
2.45
1. 10
3. 82
0. 14
0.01
0.26
0. 19
0. 60
1.58
0.06
0.01
0. 51
2.16
0.05
0.01
0. 18
0. 14
0.38
0.88
0.34
0.08
0.80
2. 10
-------
TABLE 48.
BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9, 10° and 20°F/min) (Continued)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal Originally)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
BR-74-13
Feed
0.04
0.06
0.96
0.43
1.49
150.00
256.62
0. 11
0.16
2.45
1. 10
3.82
Pretreated W. Kentucky No. 9
20
1500
0
+ 50
0.23
0.01
0.06
0.79
1.09
57.24
- 50
Float
-17.33-
•52.09-
212.14
43.06
Sink
0.86
0. 17
0.00
0.23
1.26
0. 14
0.02
0.05
0.75
0.96
0.37
0. 15
0.00
0.38
0.90
169.08
0.13
0.01
0.03
0.45
0.62
1.82
0.36
0.00
0.49
2. 67
0.06
0.01
0.02
0.32
0.41
0.63
0.25
0.00
0.64
1.52
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
0.06
0.79
0.85
87.43
0.05
0.75
0.80
91.1
B75123028
-------
TABLE 49. BATCH REACTOR RUN DATA (PRETREATED WESTERN KENTUCKY NO. 9 RAPID HEATUP)
Run No.
Coal Type
Heating, Rate, ?F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H2O
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Weight, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt *><, Original Sulfur Removed
Pretreatment
W.
Coal
5.9
33.4
0.00
0.07
2. 30
0.97
3.34
100.00
100.00
0.00
0.07
2. 30
0.97
3.34
Ky. No. 9
Pretreated Coal
1. 8
32.3
0. 13
0. 19
2.87
1.29
4.48
85.54
14.46
14.46
85.54
0. 11
0. 16
2.45
1. 10
3.82
2.87
1.29
4.16
BR-74-18
Pretreated W. Ky. No. 9
Rapid
1500
0
Feed Residue
0. 13
0. 19
2. 87
1.29
4.48
150.00
85.54
0. 11
0. 16
2.45
I. 10
3.82
From Feed
0.98
0.06
0. 19
1.47
2.70
105.00
30.00
30.00
59. 88
0.58
0.04
0. 11
0. 88
1.61
0. 19
1.47
1.66
76.96
BR-74-19
Pretreated W. Ky. No. 9
Rapid
1500
30
Feed Residue
0. 13
0. 19
2. 87
1.29
4.48
150.00
85.54
0. 11
0. 16
2.45
1. 10
3. 82
1.41
0.03
0.06
1.06
2.56
93.00
38.00
38.00
53.03
0.75
0.02
0.03
0.56
1.36
0.06
1.06
1. 12
84.55
B75020188
No lime.
-------
to
5.0
4.0
3.0
5 2.0
1.0
O RAPID HEAT-UP
A FLOAT
D +50
V PRETREATED COAL
^\ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^JL^^^^^^^^^j^^^j^^^^^^^^^^^^
600 800 1000 1200 1400 1600 1800
TEMPERATURE, °F
A75I229I9
Figure 33. Batch reactor char-sulfur content.
-------
TABLE 50. BATCH REACTOR RUN DATA (PRETREATED PITTSBURGH SEAM, W. VA.)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt %
H20
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Wt, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total 2.91
Wt % Original Sulfur Removed
From Feed
Wt % Original Sulfur Removed
From Original Coal
Pretreatment
Pittsburgh seam, W. Va
750
Coal Pretreated Coal
7.7
33.8
0.00
0.05
1.49
1.37
2.91
100.00
100.00
0.00
0.05
1.49
1.37
2.91
0.00
0.05
1.49
1.37
1.2
33.0
0.09
0.10
1.24
1.42
2.85
85.64
14.36
14.36
85.64
0.08
0.08
1.05
1.20
2.41
1.24
1.42
BR-74-14
2.66
22.68
Pretreated Pittsburgh seam, W. Va.
5
1500
0
Feed +50 -50 Float Sink
0.03
0.03
0.41
0.47
0.94
150.00
256.92
0.08
0.08
1.05
1.20
2.41
0.38
0.06
0.02
0.41
0.87
97.93
0.37
0.06
0.02
0.40
0.85
0.02
0.41
0.61
0.11
0.02
0.06
0.80
126.60 -
15.60 -
46.80 -
118.91
0.73
0.13
0.02
0.07
0.95
0.29
0.00
0.00
0.73
1.02
52.63
0.15
0.00
0.00
0.38
0.53
0.00
0.73
0.58
0.09
0.04
0.38
1.09
164.21
0.95
0.15
0.07
0.62
1.79
0.43
82.57
85.57
0.73
84.23
86.94
-------
TABLE 50. BATCH REACTOR RUN DATA (PRETREATED PITTSBURGH SEAM, W. VA.) (Continued)
ui
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt % Feed
H2°
Volatile Matter
Sulfur, wt %, as
Sulfide 0.03
Sulfate 0.03
Pyritic 0.41
Organic 0.47
Total 0.94
Weight, g
Initial 150.00
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Wt, Ib, as
Sulfide 0.08
Sulfate 0.08
Pyritic 1.05
Organic 1.20
Total 2.41
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
Wt % Original Sulfur Removed
From Original Coal
BR-74-15
BR-74-16
Pretreated Pittsburgh
5
1500
30
+50
0.38
0.04
0.01
0.40
0.83
256.92 90.50
0.34
0.04
0.01
0.36
0.75
0.01
0.40
0.41
84.65
87.28
seam, W. Va.
Float Sink
0.71
0.07
0.01
0.17
0.96
1 ?fi fifi
i A fin
J_O . UU
AR nn
125.31
0.89
0.09
0.01
0.21
1.20
0.19
0.13
0.02
0.50
0.84
42.38
0.08
0.06
0.01
0.21
0.36
0.02
0.50
0.52
90.87
92.44
0.59
0.09
0.01
0.23
0.92
173.43
1.02
0.16
0.02
0.40
1.60
Pretreated Pittsburgh seam, W. Va.
5
1500
0
Feed +50 —50 Float Sink
0.03
0.03
0.41
0.47
0.94
0.08
0.08
1.05
1.20
2.41
0.23
0.05
0.01
0.66
0.95
256.92 97.79
0.22
0.05
0.01
0.65
0.93
0.01
0.66
0.67
72.60
77.32
0.48
0.04
0.01
0.32
0.85
120.30 -
19.8 -
59.4 -
108.26
0.52
0.04
0.01
0.35
0.92
0.19
0.02
0.00
0.84
1.05
56.78
0.11
0.01
0.00
0.48
0.60
0.00
0.84
0.84
80.08
83.51
0.44
0.10
0.01
0.37
0.92
149.27
0.66
0.15
0.01
0.55
1.37
-------
TABLE 50. BATCH REACTOR RUN DATA (PRETREATED PITTSBURGH SEAM, W. VA.) (Continued)
Run No.
Coal Type
Heating Rate, °F/min
Terminal Temperature, °F
Holding Time, min
Lab Analysis, wt%
HO
Volatile Matter
Sulfur, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Weight, g
Initial
Treated
Weight Loss, %
Of Total Weight
Of Coal Weight
Reduced Data
(100 Ib Coal in Feed)
Weight, Ib
Sulfur Wt, Ib, as
Sulfide
Sulfate
Pyritic
Organic
Total
Sulfur Content, wt %, as
Sulfide
Sulfate
Pyritic
Organic
Total
Wt % Original Sulfur Removed
From Feed
Wt % Original Sulfur Removed
From Original Coal
*No lime in this test.
BR-74-17*
Pretreated Pittsburgh seam, W. Va.
5
1500
0
Feed Treated Coal
0.09
0.10
1.24
1.42
2.85
150.00
85.64
0.08
0.08
1.05
1.20
2.41
0.72
0.05
0.09
1.05
1.91
103.00
31.33
31.33
58.81
0.42
0.03
0.05
0.62
1.12
0.09
1.05
1.14
72.20
76.98
-------
the coal had not been fully pretreated. Screen separation showed more +50
material recovered than initially charged. Lime has evidently been trapped
by the caked coal particles and increased the weight of the +50 fraction
Because of this dilution with lime, the coal fraction appears to have a lower
percentage of sulfur. The float portions of the first three tests show low
sulfur but, again, this may be due to incomplete separation. Run BR-74-17
was made with coal only and, although the coal was badly caked, sulfur was
still reduced to 1.14% in the final residue calculation. With the proper
pretreatment, avoiding caking, it is expected that the sulfur can be reduced
to levels comparable to Western Kentucky No. 9 coal.
GAS SAMPLE ANALYSIS
Batch Reactor
Analyses for batch reactor off-gas, on an air-free basis, are shown in
Table 51. These data were taken from grab samples collected during the peak
temperature period of the run. While not identical to the gas concentrations
expected from a continuous operation, the species and distribution should be
generally indicative of the off-gas to be obtained from a continuous unit.
The t^S is derived from reaction with coal sulfur, while the longer-chain
molecules can be attributed to devolatilization.
Pilot Reactor Runs
Pilot reactor off-gas sample analyses are shown in Table 52. All of these
runs were made at temperatures of 1200°F or lower. The gases containing sulfur
are quite varied and many are devolatilization products only, caused by the
lower operating temperature. No H^S was detected in any of the samples and
sulfur balances could not be made for these runs. Hydrogen sulfide is assumed
to be lost to adsorption by the reactor and sample container or to condensation
between sampling and analysis.
Modified Batch Reactor
Gas sample analyses for the modified batch reactor are shown in Tables
53 through 58. Tables 53 through 55 are for pretreated Western Kentucky No. 9
coal and Tables 56 through 58 are for pretreated Pittsburgh seam, West
Virginia coal. For these data, grab samples were collected while the reactor
was being heated; samples were taken when possible at temperatures of 800 ,
1200°, and 1500°F.
Table 53 lists off-gas constituents at a reactor temperature of 800°F.
The ea<9 as exoected, is mostly hydrogen with some carbon species from the
S£l? No sulfur compounds were detected in the gas samples for the first four
tests. The reason for this effect is unknown; perhaps the Ime was effectively
removing the sulfur-containing gases at the time the sample was taken. The
runs in which sulfur was detected show several species, but no H2S.
In Table 54, the analyses are shown for samples taken at 1200°F. These
show generally higher values for the carbon species. However, the amounts of
127
-------
TABLE 51. BATCH REACTOR GAS ANALYSIS - ILLINOIS NO. 6 COAL
No. 14 16 18 19 20
Mass Spectrometer Analysis,
mol %
Nitrogen 10.85 5.3 16.3 16.7 24.0
Carbon Monoxide 0. 1 0. 04
Carbon Dioxide 0. 02
Hydrogen 88.75 94.3 83.5 83.1 76.0
Methane 0.1 0.13 0.16
Ethane 0. 03
Propane 0.01
n- Butane 0. 02
£ Ethyl ene 0.01
oo
Propylene 0.01
Toluene 0. 14
Argon 0. 40 0. 06
Chroma tograph Analysis, ppm
Hydrogen Sulfide 15.0 15.2 18.6 63.0
Carbonyl Sulfide 0.7 1.9 0.5 0.9
Methyl Mercaptan 1. 3
Ethyl Mercaptan 11.9 2.2 6.3 2.2 3.4
Thiophene 2. 4 0. 7
Dimethyl Disulfide 0.3 0. 7 0.4
t^Amyl Mercaptan 10. 5 1.0
Methylethyl Disulfide 1.1 28.5
C6 to C8 Sulfides
-------
TABLE 52. PILOT REACTOR GAS ANALYSIS - ILLINOIS NO. 6 COAL
Run No. VII VIII A VIII B IX A IX B IX C X XI XII A XII B
Mass Spectrometer
Analysis, mol %
Nitrogen
Carbon Monoxide
Carbon Dioxide
Hydrogen
Methane
Ethane
M > Cz
to
vO
Chromatograph Analysis,
ppm
Carbonyl Sulfide
Ethyl Mercaptan
n-Propyl Mercaptan
Thiophene
Dimethyl Disulfide
Methylethyl Disulfide
Diethyl Disulfide
C5H12S
^6^148
> C6H14S
1.65 1.95
1.77 1.61
0.16 0.03
93.85 95.40
1.77 0.59
0.19 0.05
0.61 0.37
1.72 3.13
1.60 2.19
0.03 0.17
94.72 91.06
1.11 2.51
0.17 0.27
0.65 0.67
1. 1
0.4
4. 5
1.6
1.1
1. 5
13.8
14.6
6.5
2. 53
2.07
0.03
93. 55
1. 27
0. 14
0.41
2.7
2.6
1. 1
10.7
2.1
1.2
5.2
38.9
67. 5
62.7
1.03
1.84
0.01
95.52
1.15
0.09
0. 36
2.5
2.6
1. 2
9.0
4.6
4.5
6.4
34.8
67.7
114.4
1.3
2. 5
0.09
91.5
4.0
0. 21
0.40
1.5
0.9
0.4
9.3
0.3
0.3
2.6
28. 1
41.7
81.4
1. 5
1.8
0.03
93.4
2.2
0.29
0.78
3.6
4.7
1.6
17.7
8. 7
2.7
43. 9
28. 7
8. 1
1.81 2.09
2.17 2.56
0.34 0.03
92.40 9L29
2.65 2.79
0.18 0.41
0.45 0.83
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TABLE 53. MODIFIED BATCH REACTOR GAS ANALYSIS (800°F) - PRETREATED WESTERN KENTUCKY NO. 9 COAL
Run. No.
Mass Spectrometer Analysis, mol %
Nitrogen
Carbon Monoxide
Carbon Dioxide
Hydrogen
Methane
Ethane
Chromatograph Analysis, ppm
Carbonyl Sulfide
Carbon Bisulfide
Dimethyl Sulfide
Thiophene
Dimethyl Disulfide
BR-74-7 BR-74-8 BR-74-9 BR-74-11 BR-74-12 BR-74-13
0. 5
99.0
0.4
0. 1
*
0.9 1.0 0.1
0.1 0.1 0.1
0.3
99.8 99.0 98.5 99.6
0.1 0. 1 0.1 0.2
* * *
1.0
3. 5
1.6
53.0
4.6
4. 5
99.9
0.1
1.6
0.9
1.6
2.8
2.2
11.9
8.9
"No sulfur detected.
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TABLE 54. MODIFIED BATCH REACTOR GAS ANALYSIS (1200°F) - PRETREATED WESTERN KENTUCKY NO. 9 COAL
Run No.
Mass Spectrometer Analysis, mol %
Nitrogen
Carbon Monoxide
Carbon Dioxide
Hydrogen
Methane
Chromatograph Analysis, ppm
Carbonyl Sulfide
Carbon Bisulfide
Thiophene
BR-74-7
BR-74-8
BR-74-11
BR-74-13
2.0
0.1
0.6
96.8
0.5
1.0
1.0
0.3 1.6
0.2 0.2
0.4
98.7 97.4
0.8 0.4
*
2.0
0.2
0.4
1.3
0.6
0.2
97. 2
0.7
1.6
0.4
No sulfur detected.
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TABLE 55. MODIFIED BATCH REACTOR OFF-GAS ANALYSIS (1500°F) -
PRETREATED WESTERN KENTUCKY NO. 9 COAL
Run No. BR-74-7 BR-74-13
Mass Spectrometer Analysis, mol %
Nitrogen 0. 7 0. 3
Carbon Monoxide 0. 2 0. 3
Carbon Dioxide 0. 1
Hydrogen 98. 5 98.6
,_, Methane 0. 5 0.8
NJ
Chromatograph Analysis, ppm
Carbonyl Sulfide 0. 5 1.9
Carbon Disulfide 0.7 0.7
-------
TABLE 56. MODIFIED BATCH REACTOR OFF-GAS (800 F) -
PRETREATED PITTSBURGH SEAM (W. VA.) COAL
OJ
u>
Run No.
Mass Spectrometer Analysis, mol
Nitrogen
Carbon Monoxide
Carbon Dioxide
Hydrogen
Methane
Chromatograph Analysis, ppm
Carbonyl Sulfide
Carbon Bisulfide
Thiophene
BR-74-14
3.0
0.3
96.6
0.1
1.0
1.8
BR-74-15
1.6
BR-74-16
1,3
1.0
0.4
99.5
0. 5
97.8
0. 1 0. 1
660
95
12
100
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TABLE 57. MODIFIED BATCH REACTOR OFF-GAS (1200°F)
PRETREATED PITTSBURGH SEAM (W. VA.) COAL
Run No. BR-74-14 BR-74-15 BR-74-16
Mass Spectrometer Analysis, mol %
Nitrogen 0.8 2.4
Carbon Monoxide 0. 3
Hydrogen 99. 0 97. 2 99.4
Methane 0. 2 0.4 0.3
Chromatograph Analysis, ppm * *
Carbon Bisulfide 0.6
sulfur detected.
-------
TABLE 58. MODIFIED BATCH REACTOR OFF-GAS (1500°F) -
PRETREATED PITTSBURGH SEAM (W. VA.) COAL
BR-74-15
Run No. BR-74-14 BR-74-15 (15 min into holding)
Mass Spectrometer Analysis, mol %
Nitrogen 2.6 0.4 1.4
Carbon Monoxide 0.5 0.4
Carbon Dioxide 0. 3 0. 1
Hydrogen 96. 9 98. 7 97. 9
Methane 0.2 0.4 0.2
Chromatograph Analysis, ppm
Carbonyl Sulfide 0. 7 0. 5 2. 3
Carbon Disulfide 1.5 0. 9
Thiophene 3. 8
C5H12S 0.8 1.8
-------
sulfur gases are lower than in the same tests at 800°F. This effect may be
due to reduced devolatilization at the higher temperature.
Analyses of gas samples at 1500 F are shown in Table 55. These are only
slightly different than the 1200°F analyses and show very low sulfur content.
Table 56 shows analyses for off-gases at 800°F of the pretreated
Pittsburgh seam, West Virginia coal. All analyses are typical except the
sulfur types in BR-74-16. This test shows much higher values than any other
tests and the results are unexplained.
Analyses of gases at 1200°F are shown in Table 57. Only a small amount
of sulfur was detected in BR-74-14 and none was detected in the other two
samples.
Table 58 shows analyses for gases at 1500°F. Once again, there are few
sulfur-bearing gases and they are low in value.
The sampling and analysis of sulfur-bearing gases was inadequate for
these tests. While balances can be made for the other coal constituents, it
was not possible to make a sulfur balance for any of the runs. This is
possibly caused by the reactivity of some of the species with their environment.
The cooling of the sample between sampling and analysis may also be part of
the problem. Future work must take these effects into account; a more complete
analysis is required.
CONCLUSIONS
A pretreatment step is required for coals of the Midwestern and Eastern
seams. This prevents agglomeration and caking in subsequent treatment for
sulfur removal. The pretreatment also seems of benefit in removing sulfur.
Analysis of the hydrodesulfurization test results shows that with proper
conditions of time, temperature, heating rate, etc., a substantial sulfur
reduction is achieved. This is true for all the coals tested to date. Some
coals require more severe conditions because of their original sulfur content
or the seam location.
Use of lime as an acceptor may not be as beneficial as originally antici-
pated. While runs made with lime show less sulfur in the coal residue, there
is also less residue recovered and some carbon loss to the lime fraction.
Gas analysis shows some heating value is available from the hydrocarbons
present.
Further work is required before conclusively determining conditions for
treatment of each coal, its final sulfur content, or the characteristics of
the gaseous or any other stream from the process.
136
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PROCESS CONCEPT
A process concept flow sheet, incorporating the results from the thermo-
balance and batch reactor runs for the Western Kentucky No. 9 coal, is presented
in Figure 34. Streams not characterized have not yet been studied in the
program. The data presented on Figure 34 are tentative; they are taken from an
analysis of thermobalance and batch reactor tests that generate only small
samples and are batch-type, not continuous as the process would be. The pilot
unit, with a continuous feed and discharge system, will generate larger samples
and better material and energy balances.
The process, as it is now conceived, yields a solid fuel meeting Federal
EPA standards for direct combustion (1.2 Ib S02/million Btu). The fuel con-
tains 50% by weight of the input coal and 60% of the original carbon. Heat
energy would be available from gas, tars, and oils generated both in the pre-
treater and hydrotreater. Carbon and hydrocarbon values in the lime would be
used as a heat source for regeneration. Elemental sulfur would be a by-product.
137
-------
u>
00
GASES
Ib
H20 114.7
C 70.1
H 25.4
S 9.5 PRETREATEO
0 270.5 COAL
N 1000. 1 |b
|H20 14.1
ASH 296.0
C 1199.0
H 62.2
GASES
Ib
HaO 14,1
C 305.7
H 382.2
S 15.9
0 104.7
N 9.9
COa 23.3
S bb.B
0 IZ2.2
PRETREATER N 25.2 ,™D™^
SIZED COAL 750°F
Ib
H?0 118.0
ASH 296.0 I
C 1269 1 T L
H 876 1 ">
S 76.3 AIR ASH 3207-2
0 127.0 15 i- I3D
N 26-° H20^01 £ 442|
0 265.7 0 Z72 8
N 999.3 N 0.4
C02 23.6
BASIS: 1 TON W. KENTUCKY COAL
(As Received)
linn«F MIXED RESIDUE
i
r
L
Ib
^— ^— fltn ^sm ^
C 881.9
H 24.6
S 53.9
0 207.7
N 15.6
C02 113.9
t
MAKEUP
LIME
1 |
HYDRO-
ZATION
SEPARATION
LIME
REGENERATION
^- CONDENSER
TREATED COAL
Ib
ASH 206.4
C 762.1
H 13.6
0 .1
N 11.3 .
SPENT LIME
Ib sin
ASH 3296.8 REM(
C 119.8
H 11.0
S 4B.4
0 206.6
N 4.3
CO 113.9 '
_^ GAS
CONVERSION
i
COOLING
TOWER
r
*
SEPARATOR
TARS
AND
OILS
™ — ^ SULFUR
BY-PRODUCT
GAS
H2
MAKEUP HYDROGEN — ^ ^GENERATION
B-74-II48
Figure 34. Flow sheet for proposed process.
-------
FUTURE WORK
NECESSITY FOR LIME
One of the primary objectives to consider is the necessity of using lime.
Some data indicate that the use of lime is not imperative; the process could
be simplified if the lime were eliminated. Problems have been experienced
with coal-lime separations, loss of carbon values to the lime, and capture of
lime by the coal. These problems were not unexpected in the original plan for
the process, but the effect is more pronounced than desirable.
Elimination of the lime would reduce the complexity of the process. The
reactors could be made smaller, and gas usage would decrease because less
material would be handled. Larger off-gas treatment facilities would be
necessary to handle the increased sulfur in the off-gas. Studies must be made
to determine which operating approach is economically and operationally superior.
OTHER COALS
Tests using other, typical sulfur-bearing coals should be made in the
thermobalance and batch reactors. The results will be compared with results
already obtained. The relative value of heating rates and holding times will
be evaluated.
PILOT UNIT
Tests should be made on the 10-inch unit used previously. The larger
scale operation and increased material generated are necessary for determining
details to complete the process flow sheet. In particular, the determination
and distribution of sulfur types in the off-gas during continuous operation is
needed, so that treatment facilities can be designed.
If a heating rate must be imposed on the particle (other than the rapid
heat-up in the fluidized-bed arrangement), the 10-inch unit will require
modification. Further work is needed in the thermobalance and batch reactors
to determine the optimum heat-up rate.
OVERALL CONCEPT DESIGN
When test work is completed, data would be used to generate an overall
conceptual design for the process. This would include energy and material
balances, economic studies, and all of the treatment steps to produce a low
sulfur fuel from coal.
139
-------
REFERENCES CITED
1. Clark, S. P., Jr., Ed., Handbook of Physical Constants. New York:
Geological Society of America, 1966.
2. Kubaschewski, 0. and Evans, E., Metallurgical Thermochemistry.
London: Butterworth-Springer, 1951.
3. Rosenquist, T., "A Thermodynamic Study of the Iron, Cobalt, and
Nickel Sulphides," J. Iron Steel Inst. (London) 176, 37-57 (1954)
January.
4. Rossini, F. D. et al., Selected Values of Chemical Thermodynamic
Properties. Washington, B.C.: U.S. Government Printing Office,
1952.
5. Snow, R. D., "Conversion of Coal Sulfur to Volatile Sulfur Compounds
During Carbonization in Streams of Gas," Ind. Eng. Chem. 24, 903-9
(1932) August.
6. Vestal, M. L. and Johnston, W. H., "Desulfurization Kinetics of Ten
Bituminous Coals," Report No. SRIC 69-10. Baltimore: Scientific
Research Instruments Corp., 1969-
140
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TECHNICAL REPORT DATA
(Please read law-act ions on the reverse before completing)
JPA^600/^-77-206
,.TITLE AND SUBTITLE
Pilot Plant Study of Conversion of Coal to Low Sulfur
Fuel
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S) ~ — —
Donald K. Fleming and Robert D. Smith
^PERFORMING ORGANIZATION NAME AND ADDRESS
Institute of Gas Technology
3424 South State Street
Chicago, Illinois 60616
12. SPONSORING AGENCY NAME AND ADDRESS "
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
October 1977
8. PERFORMING ORGANIZATION REPORT NO
To. PROGRAM ELEMENT NO.
1AB013; ROAP 21AFJ-040
11. CONTRACT/GRANT NO.
68-02-1366
13. TYPE OF REPORT AND PERIOD COVERED
Final: 6/73-3/75
14. SPONSORING AGENCY CODE
EPA/600/13
15. SUPPLEMENTARY NOTES jERL-RTP project officer Lloyd Lorenzi Jr. is no longer with
EPA. For details contact Lewis D. Tamny, Mail Drop 61, 919/541-2709.
16. ABSTRACT
The report gives results of a program to develop, on bench and pilot scales,
operating conditions for the key step in the IGT process to desulfurize coal by thermal
and chemical treatment. This process, to date, uses the 'sulfur-getter' concept. (A
sulfur-getter is a material that has a greater chemical affinity for sulfur than coal
has.) Lime was the sulfur-getter for this program. In Phase I, a coal/lime mixture
was experimentally treated at atmospheric pressure with a reducing gas in a heated,
fluidized bed reactor, which could treat up to 200 Ib/hr of mixture to 1200 F. The
coal was Illinois No. 6, containing about 3% sulfur. Initial work resulted in the dis-
covery that less sulfur was removed than expected. Two factors were believed res-
ponsible: the coal heat-up rate in the fluidized bed was nearly instantaneous, which
appeared to cause organic sulfur fixation; and the coal showed signs of weathering
(therefore, the total sulfur content was not readily available for hydrogen treatment).
Phase n redirected the program to the operation of smaller scale units featuring:
controlled heat-up rates, an increased number of tests over a broader range of
conditions (with savings in time and manpower), and coal samples from several U.S.
mines A coal/lime mixture was treated with hydrogen, in batch reactors, to 1500 F.
Tests indicated that lime treatment does not capture all sulfur released from the coal.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Coal
Conversion
Desulfurization
-alcium Oxides
Fluidizing
3. DISTRIBUTION STATEMENT
Unlimited
b.lDCNTIFIERS/OPEN ENDED TERMS
Air Pollution Control
Stationary Sources
IGT Process
Thermal Treatment
Chemical Treatment
CLASS (TliisReport)
Unclassified
20 srxfuHITY CLASS (This page)
Unclassified
c. COSATI (-kid/Group
13B
08G,21D
14B
07A,07D
07B
13H
21. NO. OP PAGFS
153
22. PFilCE
Form 2220-1 {9-73J
141
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MINISTERIO DE MINAS Y PETROI-EOS
ilNISTlTUTO NACIONAL. DE INVESTIGACIONES GEOL-OGICO-MINERAS
INGEOMINAS
CERTIFICADO DE PAZ Y SAUVO
L-os Suscri-f-os funcionarlos del InstH-uto Naclonal de Inves-Hgaciones Geologlco-Mineras
CERTIFICAN : que
quien se ausen+a del Ins-M + u fo por
19
con feoha
no deja asuntos pendienl-es por concepto de
Rondos reclbldos, legal izacion de cuen + as y elementos a cargo, en sus res-
pec*t-ivas dependencies.
DEPENDENCIA
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