U.S. Environmental Protection Agency Industrial Environmental Research EPA'600/7-77-029
Office of Research and Development Laboratory «>TT
Research Triangle Park, North Carolina 2771 MdrCn 1977
SORBENT SELECTION FOR THE
CAFB RESIDUAL OIL GASIFICATION
DEMONSTRATION PLANT
Interagency
Energy-Environment
Research and Development
Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into seven series. These seven broad categories
were established to facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously planned to foster
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are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the effort
funded under the 17-agency Federal Energy/Environment Research and Development
Program. These studies relate to EPA's mission to protect the public health and welfare
from adverse effects of pollutants associated with energy systems. The goal of the
Program is to assure the rapid development of domestic energy supplies in an environ-
mentally-compatible manner by providing the necessary environmental data and
control technology. Investigations include analyses of the transport of energy-related
pollutants and their health and ecological effects; assessments of, and development
of, control technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
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This document is available to the public through the National Technical Information
Service, Springfield, Virginia 22161.
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EPA-600/7-77-029
March 1977
SORBENT SELECTION FOR THE CAFB
RESIDUAL OIL GASIFICATION
DEMONSTRATION PLANT
by
E.P. O'Neill, D.L Keairns, and MA Alvin
Westinghouse Research Laboratories
Pittsburgh, Pennsylvania 15235
Contract No. 68-02-2142
Program Element No. EHE623A
EPA Project Officer: SI. Rakes
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, North Carolina 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
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CONTENTS
1. Introduction '.'.'.. . -' .'......'........'.. 1
2. Conclusions1 ' .' .' .' .' . .' -' ..'.'...' ..'..'...-'.. 3
3. Recommendations' ...'...'...........'..'..'. 4
4. Selection Criteria ' .' .' .' .' ..'.-'..'..'..' .-'..'.. 5
Acceptor Properties of the Stone for Sulfur Removal.1 . 5
Attrition '.'.'......... .' ..'........ 6
Grain Size1 .' .' .' .' .' . .'..'.'..' ..'.-'..'.-'.. 6
Trace Elements' -'............-...... 6
5. Candidate Sorbents '.'.'.' .'.'.' ..'..'..,.'..'..'.. 7
Limestone Deposits in Texas and Mexico1 ..'..'..'.. 7
Limestone Cost .'..'. .' .'.'.'. .' . ' . . 9
Stones Selected for Test Program .....'...... 11
6. Limestone Selection Test Program '.'..' ....'..'..'.. 12
Chemical Analyses ' ,'.'.. .' .' . .' .......... 12
Physical Characterization .' . '..'.... 12
Attrition Tests '.'.,' '..'..'..'. 12
Chemical Reactivity as Sulfur Sorbents ...' .'... 17
References1 . . .' .' .' . . . .'.'.'. .'..'. . .' . 19
Bibliography of Texan and Mexican Limestones -...-'...... 20
Appendix
Texas Limestone Producers1 .........' ........>. 22
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SECTION 1
INTRODUCTION
The CAFB (Chemically Active Fluid Bed) process is being developed
under EPA sponsorship to retrofit electrical utility power plants to
utilize high sulfur residual fuel oils or refinery bottoms. Coal is
also being investigated as a fuel. In this process, the residual fuel
oil is gasified by injecting it into an air-fluidized bed of lime
operating at temperatures from 870-920°C, where the fuel sulfur is
trapped in solid form, and the desulfurized hot gas (^ 870°C) is used to
fire a steam boiler. The process has been developed in a 1 MW pilot
plant by Esso at their Abingdon (England) Research Center.^ Successive
evaluations of the process by Westinghouse led to a demonstration plant
design and cost estimate for a 50 MW demonstration plant. Currently
Foster-Wheeler are under contract to build a 16 MWe retrofit CAFB unit
for the San Benito (Texas) station of the Central Power and Light Co.
A simplified illustration of the process concept is shown in Figure 1.
The demonstration plant design incorporates a spent sorbent regenerator
to air oxidize the calcium sulfide to sulfur dioxide and calcium oxide.
The gas stream from the regenerator contains 6 to 10 percent by volume
sulfur dioxide and is converted to elemental sulfur.
In support of the Westinghouse design, experimental tests were carried
out to identify suitable limestones from the New England region for use
in the process at a Providence Rhode Island site. A change in the
demonstration plant site to San Benito mandated that limestones available
in the Texas area be assessed for their suitability in the CAFB process.
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Fluid Bed
Gasifier
\
Limestone
20%
High Sulfur
Petroleum Fraction
Conventional Boiler and
Steam-Turbine Generator
Clean Fuel Gas
Particulates
80%
Dwg.6408"25
Air Preheat
ffifflffi
Spent Stone (CaO, CaS,
CaSO J to regenerator
or processing for disposal
or utilization
-Q-
Induced
Draft
Fan
Q^Air
Forced
Draft
Fan
Gasifier Fan
Stack
Fig. 1 -CAFB gasification power plant schematic
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SECTION 2
CONCLUSIONS
Of the stones tested, the limestone from the Uvalde County mine of
White's Mines, Inc. is the best choice for use at the San Benito plant.
The stone from Parker Brothers is the second choice.
It is clear that the current test procedure did not lead to clear
distinctions between most of the stones tested. The cost of the sorbents
should therefore determine the choice of sorbent.
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SECTION 3
RECOMMENDATIONS
1. Further investigations on these stones at the laboratory level
should be pursued when further data describing operating experience on
the Esso CAFB pilot plant become available. The principal questions
which should be addressed are
(a) How much attrition occurs under reducing/sulfidation conditions.
(b) What is the reactivity of the sorbents after exposure to the
regeneration process.
(c) Do these stones differ as to their suitability for the stone
disposal process chosen for the San Benito plant.
2. Operating experience on the Esso plant, since 1973 with different
sorbents should be reviewed, to develop superior sorbent selection tests.
3. Two other sources of calcium carbonate for the CAFB demonstration
plant should be investigated: carbonates from marine sediments on the
Gulf-coast, and industrial waste products containing calcium carbonate.
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SECTION A
SELECTION CRITERIA
Previous work by Westinghouse in evaluating processes which use
calcium-based sorbents for high temperature desulfurization (i.e., in
fluidized bed coal combustion, low Btu coal gasification, and CAFB
gasification), led to the following general categories of criteria for
selecting sorbents.^>^
acceptor properties of the stone for sulfur removal
attrition resistance of the stone
trace and minor element emission characteristics
regeneration characteristics
suitability of spent sorbent for final processing for disposal
economic availability of the stone
The development of rigid selection criteria based on the above
categories is an evolutionary process. The variety of process options
available in the desulfurization circuit of the gasification system
require that a great deal of flexibility be built into the criteria.
For example, fifteen process alternatives have been identified for
disposal of the spent sorbent. It was not realistic to attempt an
assessment of the impact of disposal processes on each candidate stone.
The procedure followed was to identify candidate stones using
available literature and expertise on the limestone industry in the area
surrounding San Benito. The attrition as measured by elutriation losses
suffered by samples of these stones in a small fluidized bed unit under
calcination conditions, was measured. The samples were evaluated for
their reactivity tc hydrogen sulfide in a fuel gas mixture at 871°C.
Trace element analyses of the minerals were carried out.
ACCEPTOR PROPERTIES OF THE STONE FOR SULFUR REMOVAL
The standard test for sulfur removal is carried out by sulfiding
limestone in a modified duPont thermogravimetric reactor using 0.5% I^S/
fuel gas as reactant at 871°C. The stone particle size selected for
testing was 1000-1200 micron diameter. Stones which have satisfactory
desulfurization performance form 30% (molar) calcium sulfide within 7 to 8
-------
minutes of exposure to the gas, (limestone 1359, Denbighshire limestone).
The test may be regarded as a necessary, but not sufficient condition
for adequate desulfurizing properties. All limestones tested to date
have proven satisfactory sulfur acceptors in this test. It appeared from
the most recently available test data from Abingdon, that in fact there
is little difference in the intrinsic desulfurization performance of
different stones.
ATTRITION
The attrition test is thought to give a reasonable guide to behavior
in the Esso batch units. As reported previously,3 Pfizer Adams calclte
and Conklin limestone showed high attrition losses in our tests, and
were rejected by Esso for the same reason on the basis of their own tests.
Aragonite and limestone 1359 suffered low attrition losses on their unit
and in the Westinghouse test and were thought suitable as sulfur sorbents,
Denbighshire limestone had an intermediate type of behavior on the
Exxon unit: in calcination its elutriation losses were high relative
to limestone 1359, in agreement with the Westinghouse attrition test.
However, on sulfidation/regeneration cycling it had the,lowest attrition
rate of stones tested.
The current procedure is to accept sorbents with attrition losses
of ^ 2%, reject those with attrition losses of ^ 10%, and take no
decision based on attrition in the case of stones with intermediate
attrition behavior.
GRAIN SIZE
Currently, it is believed that massive-grained sorbents such as
Pfizer Adams, or Canaan dolomite are subject to heavy attrition when
fully calcined. It is also thought that extremely fine-grained sorbents
are also prone to attrition. Satisfactory performance is expected from
stones in the range [5-250] micron grain size.
TRACE ELEMENTS
Trace elements are of significance only in that they might contribute
to overall plant emissions. None of the elements considered to be of
vital environmental concern are found at high levels in limestones. The
atomic emission analyses carried out are essentially a check to see if
the normal pattern of trace metals is found in any given limestone.
-------
SECTION 5
CANDIDATE SORBENTS
LIMESTONE DEPOSITS IN TEXAS AND MEXICO
Abundant surface outcrops of limestone are prevalent in Texas which
vary in the chemical composition and the physical properties of the
stone. High-calcium limestone is quarried in a restricted zone within
the Lower Cretaceous age, outcropping in a narrow 250 mile area west of
the city of Waco, extending through Austin, north to San Antonio to
Del Rio (Fig. 2'). Major limestone producing counties (Val Verde,
Edwards, Kinney, Real Counties) lie in the southern regions of the
Edwards Plateau adjacent to the boundary demarcating central Texas from
the neighboring coastal Plain area.
These lower Cretaceous limestones include a variety of stone compo-
sitions ranging from soft argillaceous stones relatively high in clay
impurities to hard massive limestones generally high in the content of
calcium carbonate. The hard, thick-bedded and massive limestones of
the Edwards and Devils river formations are exceptionally pure. The
Report of Investigations #56 of the Bureau of Economic Geology indicates
that the average CaCOs content of the lower Cretaceous limestones is
98%, with 47% containing 97 + % CaC03. [With regard to the MgC03 content,
less than 10% were completely free of magnesium as detected by flame
photometry analysis, roughly 40% contained < 1% MgC03, and approximately
70% of the total samples contained < 3% MgC03. The non-carbonate
composition of the lower Cretaceous limestones from the Edwards Formation
had been analyzed'].
In the Gulf Coastal Plains of Texas, limestone deposits contribute
< 5% to the carbonate industry and outcrop as minor occurrences of thin
beds of impure Tertiary stone. The local deposits are commonly associated
with salt domes and Quaternary caliche, interbedded with large deposits
of unconsolidated sands and clays. The Gulf Coastal Plains region,
therefore, is an area generally lacking in carbonate material resources
with the exception of its extensive oyster shell production. Two stone
producers quarry in Calhoun and Matagordo Counties (170-220 miles from
San Benito, Texas).
The limestone in Mexico is categorized on the basis of purity and
physical characteristics as either marl, marble, metamorphic limestone
or calcite. The stone is chiefly calcium carbonate with minor trace
-------
.
2.
3.
k.
5.
6.
7.
8.
9.
10.
11.
12.
13.
1^.
15.
16.
17.
i O
18.
19.
-Limestone Quarries
Ca 1 noun
Matagorda
Uvalde
Bexar
Comal
Travi s
Wi 1 1 iamson
Burnet
Llano
Hill
Johnson
Ellis
Tarrant
Dallas
Wise
B rown
Taylor
ki 1
Nolan
Hudspeth
s
\s
\
\ . \eV_^ -
xvCcjO>-^
/ \|l8 17
Dwg. 635^52
19
Monterrey
Fig. 2 -Major limestone producing counties of Texas
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impurities of Fe2C>3, Al203, Si02, S and MgO. Analyses of limestone
located in the state of Jalisco (Fig. 3) indicated that the material
was of high purity which could be adapted for almost any industrial use,
and which could be obtained in large quantities. The typical calcium
carbonate content range is from 96.93% to 98.64% with silicon present
as S102 at 1.14% and 3.4% levels. Limestone which contains < 90% CaC03,
considered as an impure stone, locally outcrops within deposit formations,
Detailed chemical analysis of the limestone quarried in Mexico is not
obtainable.
In a review of the available literature concerning the quality and
location of Mexican limestone the following items should be considered
as determinants for potential limestone supplying sites:
1. Limestone obtained from coastal states is chiefly unconsolidated
clay material.
"2. Large limestone deposits outcrop within central Mexico, princi-
pally in the states of Nuevo Leon, Hidalgo, Mexico and Jalisco. (Plants
located in the state of Nuevo Leon, at Monterrey and Hidalgo City) are
geographically favorable for the transportation of limestone to San
Benito, Texas. The distance from the Mexican deposits to San Benito is
estimated at 160 to 175 miles. The closest Texas quarry, located in
Calhoun County, is approximately 180 miles from San Benito.
3. A high quality marble deposit is located in Vezarron de Montes,
bordering the states of Quenrataro and Hidalgo.
LIMESTONE COST
The (late 1975) cost of 3"-5" Texas limestone is $2.00/ton F.O.B.
(excluding freight and shipping costs). An additional $'2.50-3.OO/ton
depending on location has been reported for freight expenditures. High
calcium limestone, however, can be obtained from producers which quarry
in the southern counties of the Edwards Plateau (Uvalde Co., Bexar Co.)
and southeastern Balcones Escarpment, located in a 300 mile proximity
from San Benito, Texas.
Cost of the material from Mexico, dependent on the initial CaC03
content, varies from $9.95/ton ($1.25 US/ton) for low-grade material to
$19.60/ton ($2.45 US/ton) for high-purity limestone in 1968. The
production of limestone is assessed with a tax of $0.45/ton (^ $0.06
US/ton), and $6.90/ton ($0.85 US/ton) when the stone is of ornamental
or marble quality. Due to the decrease in foreign trade, exportation
of the material as either natural or crushed stone carries an additional
tax of $27.54/ton (^ $3.45 US/ton). (Price listings for 1968).
-------
Dug. I67&B7I
Massive Limestone
Deposits'
1. NuevoLeon
2. Hidalgo
3. Mexico
4. Jalisco
- Scattered Limestone
Deposits
5. Sinaloa
6. Coahuila
7. San Luis Potosi
8. Guanajuato
9. Puebla
10. Oaxaca
' \ Hidalgo City-^-
"\
5 I
0 50 100 miles
Mexico City
Guadalajara
Fig. 3 - Major limestone deposits of Mexico
-------
STONES SELECTED FOR TEST PROGRAM
The objective of the test program was to obtain and test samples
from each of the areas identified as possible sources of supply for
San Benitb.
1. No stone samples were received from active quarries in Calhoun
or Matagordo counties: one listed operator indicated that their quarry
was no longer active.
2. Samples were received from Bexar, Comal, and Burnet Counties
(^ 300 miles from San Benito1) .
3. Samples were received from Dallas Co. (450 miles from San
Senito).
4. A sample was received through Central Power and Light Company.
This sample was provided by White Mines - from their Uvalde
Co. site (^ 275 miles from San Benito).
11
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SECTION 6
LIMESTONE SELECTION TEST PROGRAM
CHEMICAL ANALYSES
The analyses of the samples received are listed in Tables 1 and
2. With the exception of the Burnet Stone which was a typical
dolomite, all the samples received were high calcium limestones ranging
from 92.5% CaC03 to 96% CaC03. The residual major impurity was silica,
with some alumina silicates. No major trace-element impurities were
found by emission spectroscopy, which yields semi-quantitative estimates
of environmentally important metals such as lead, beryllium and
vanadium.
PHYSICAL CHARACTERIZATION
Stone samples were mounted and polished for examination in the
optical microscope. None of the samples had massive-grained structures
typical of those which suffer excessive attrition on calcination. The
structure of the CP&L stone is shown in Figure 4 and it contains a fairly
wide spectrum of grain sizes. The wide distribution of grain sizes seen
in Denbighshire limestone is also shown for comparison.
ATTRITION TESTS
The extent to which the limestones were elutriated from a small
fluidized bed unit, when calcined in a flow of nitrogen, was measured
under standard conditions to obtain a relative attrition index of the
stones.
A fifty gram sample of the limestone, 1000-420 microns, was placed
in a 3 cm diameter Inconel 800 fluidized bed and heated to 850°C in a
flow of nitrogen corresponding to a superficial velocity of 70 cm/sec.
The heating rate is linear until the rate of endothermic calcination
imposes an additional burden on the electrical heaters. Calcination is
essentially complete by the time the sample reaches 830°C.
A Whatman #42 filter in the exhaust line traps fine particles
elutriated from the bed. After the experiment excess air is blown down
the exit lines .to collect any particles which lodge on the tubing walls.
12
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TABLE 1
ANALYSIS OF TRACE IMPURITIES OF TEXAS AND MEXICAN LIMESTONES BY
ATOMIC EMISSION SPECTROSCOPY. VALUES REPORTED AS WEIGHT PERCENTS,
The Ca and Mg Were Determined By E.D.T.A. Titration
Element
General Portland
Cement Company
Dallas County
Al
Ag
B
Ba
Be
Bi
Ca
Cd
Co
Cr
Cu
Fe
K
Li
Mg
Mn
Mo
Na
Nb
Ni
P
Pb
Sb
Si
Sn
Sr
Ti .
V
Zn
Zr
.04
<0.0004
<0.0004
<0.004
<0.0004
<0.0004
37.5%
<0.04
<0.0004
0.0004
<0.0004
0.3
0.04
<0.0004
0.02
<0.0004
0.008
<0.004
<0.0004
<0.04
<0.004
<0.004
0.8
<0.004
0.12
0.02
0.0004
<0.004
<0.004
Parker Bros.
Comal County
McDonough Bros,
Bexar County
.02
<0.0004
<0.004
<0.004
<0.0004
<0.004
37.0%
<0.04
0.004
<0.0004
<0.0004
0.1
0.004
<0.0004
0.008
<0.004
0.004
<0.04
< 0.0004
<0.004
<0.0004
<0.04
<0.0004
0.02
0.0004
0.0008
<0.004
<0.004
.01
<0.0004
<0.004
<0.004
<0.0004
<0.004
38.4%
<0.04
0.004
<0.0004
<0.0004
0.08
0.002
<0.0004
0.003
<0.004
0.004
<0.04
<0.0004
<0.004
<0.0004
<0.04
<0.0004
0.02
0.0004
0.0008
<0.004
<0.004
Approximate distance from San Benito, Texas:
460 miles 250 miles
235 miles
13
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TABLE 1 (Con't)
Element
Stone;
Lone Star
Ind., Inc.
Burnet County
CP&L
Stone
(White Mines)
OJvalde)
Al
Ag
B
Ba
Be
Bi
Ca
Cd
Co
Cr
Cu
Fe
K
Li
Mg
Mn
Mo
Na
Nb
Ni
P
Pb
Sb
Si
Sn
Sr
Ti
V
Zn
Zr
0.8
<0.0004
<0.0004
<0.004
<0.0004
0.0004
>10%
<0.004
<0.004
<0.0004
<0.0004
0.1
0.2
0.0008
11.8%
0.004
<0.0004
0.008
<0.004
<0.004
<0.04
<0.0004
<0.004
0.8
<0.0004
0.008
<0.004
< 0.0004
<0.004
<0.004
0.4
<0.0004
<0.004
0.0004
<0.0004
<0.0004
37.6%
<0.04
<0.0004
<0.004
0.008
0.2
0.1
<0.0004
-1%
0.04"
<0.004
0.02
<0.004
<0.004
<0.004
< 0.0004
<0.004
»v,2%
<0.004
0.08
0.04
<0.004
<0.004
<0.004
Materiales
Monterrey,
Limestone
0.03
<0.0004
<0.004
<0.004
<0.0004
<0.0004
<0.004
0.004
<0.0004
<0.0004
0.08
' 0.002
<0.0004
0.3
0.008
<0.0004
0.0004
<0.004
<0.004
<0.04
<0.0004
< 0^.004
<0.004
0.03
0.008
<0.0004
<0.004
<0.004
Friturados
Neuvo Leon
Marble
0.008
<0.0004
<0.004
<0.004
<0.0004
<0.0004
v i f\a/
>1U/0
<0.004
0.004
<0.0004
<0.0004
0.04
0.0004
0.0004
0.3
0.004
<0.0004
0.0004
<0.004
<0.004
<0.04
<0.0004
<0.004
<0.004
0.4
0.002
<0.0004
<0.004
<0.004
Minera del Norte
Monterrey, Neuvo Leon
0.03
:0.0004
:0.004
:0.004
:0.0004
:0.0004
<0.004
0.004
<0.0004
0.008
0.09
0.0008
<0.0004
0.3
0.035
<0.0004
0.0004
<0.004
<0.004
<0.04
<0.0004
<0.004
^1.5%
<0.004
0.03
0.006
<0.0004
<0.004
<0.004
Approximate distance from San Benito, Texas:
320 miles
255 miles
160 miles
160 miles
160 miles
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TABLE 2
ANALYSIS OF THE ALKALI DISTRIBUTION IN TEXAS LIMESTONES
General Portland
Cement Co.
Texas Crushed
Stone Co.
Parker
Bros.
McDonough
Bros.
Sodium
Carbonate
Non-Carbonate
Potassium
Carbonate
Non-Carbonate
Sodium
Carbonate
Non-Carbonate
Potassium
Carbonate
Non-Carbonate
58 ppm
16 ppm
221 ppm
372 ppm
Lone Star
Ind . Inc .
160 ppm
13 ppm
120 ppm
1780 ppm
45 ppm 32 ppm
10 ppm 12 ppm
151 ppm 28 ppm
127 ppm 59 ppm
White's Mines,
Inc.
72 ppm
66 ppm
148 ppm
1010 ppm
21 ppm
8 ppm
25 ppm
33 ppm
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Denbighshire Limestone
100
microns
CP and L Limestone (Texas)
FIGURE 4 - The Grain Structure of Sorbent Limestones
16
RM-67694
-------
The total weight of solids collected gives an indication of the extent
of attrition suffered by the stone tested.
Six of the stone samples were tested. One of the stones, from
McDonough Co. lost 8.05% of the initial bed weight by elutriation; the
remaining five stones lost less than 2.3% in similar tests. The McDonough
stone was rejected for further testing. The attrition test results are
summarized in Table 3.
CHEMICAL REACTIVITY AS SULFUR SORBENTS
The five remaining stones were tested for sulfur sorption activity
by calcining 20 mg samples of a 16/18 mesh sized sample (1200/1000
microns), and reacting the calcine at 871°C with a hydrogen sulfide/fuel
gas mixture, in a modified duPont thermogravimetric apparatus, as
previously described.
All of the stones tested were extremely reactive, forming 30 molar
percent calcium sulfide within eight minutes of exposure to the reactant
gas. The stones are therefore indistinguishable in this regard.
The results of the tests carried out are summarized in Table 3.
17
-------
TABLE 3
PHYSICAL AND CHEMICAL CHARACTERISTICS OF CANDIDATE SORBENTS AND
THEIR ATTRITION LOSS ON CALCINATION IN A FLUIDIZED BED
oo
Supplier and
Estimated Distance
From San Benito
In Miles
McDonough
(San Antonio)
230
General Portland
(Dallas)
460
Parker Bros.
(Houston)
220
Burnett
(Houston)
320
White's Mines, Inc.
Stone
(San Antonio)
255
Minera Del
Norte
160
Monterrey
160
Type of Stone
and Typical
Grain Size
Limestone
Fine grained
(< 20 micron)
Limestone
Fine grained
(^ 30 micron)
Limestone
(^ 20 micron
grains with 100
micron inserts)
Dolomite
Wt %
Ca Mg
38.4
37.5
37.0
21.3 11.8
Limestone 37.6
(4-30 micron)
Limestone 38.5 0.50
(< 16 micron)
Limestone 38.2 0.85
(30-200 micron)
Ignition v Attrition
Loss wt/% Loss wt %
44.2
43.2
41.4
42.1
42.6
8.05
2.23
1.92
43.3
1.04
0.6
0.4
Reactivity
Time to
30% CaS
(Minutes)
6.7
7.5
7.6
7.5
11.1
Comment
High attrition with
finegrained stone-
reject
Acceptable
Acceptable
Not tested
Very low attrition
looks promising, as
a candiate stone
Acceptable
Possible
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REFERENCES
1. Craig, J. W. T., et al, "Chemically Active Fluid-Bed Process for
Sulphur Removal During Gasification of Heavy Fuel Oil Second Phase",
Esso Research Center, report to EPA on Contract 68-02-0300,
November 1973.
2. Keairns, D. L., et al. Fluidized Bed Combustion Process Evaluation -
Residual Oil Gasification/Desulfurization Demonstration at Atmospheric
Pressure. Westinghouse Research Laboratories. Contract report to
the Environmental Protection Agency, Vols. I and II, EPA-650/2-75-027a
and b (NTIS PB 241834 and PB 241835), March 1975.
3. O'Neill, E. P. and D. L. Keairnte. Selection of Calcium-Based
Sorbents for High-Temperature Fossil Fuel Desulfurization.
Westinghouse Research Laboratories. (Paper presented at 80th AIChE
Meeting, Boston, September 7-10, 1975).
4. Keairns, D. L., et al. Fluidized Bed Combustion Process Evaluation -
Phase II - Pressurized Fluidized-Bed Coal Combustion Development,
Westinghouse Research Laboratories. EPA 650/2-75-027c, September
1975. NTIS PB 246116.
19
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BIBLIOGRAPHY ON TEXAN AND MEXICAN LIMESTONES
PUBLICATIONS:
Brown, L. F. (ed), Proceedings: Fourth Forum on Geology of Industrial
Minerals, Bureau of Economic Geology, University of Texas at
Austin, December 1968.
Dietrich, J. W. and J. T. Lonsdale, Mineral Resources of the Colorado
River Industrial Development Association Area, Report of
Investigations - No. 37, Bureau of Economic Geology, University
of Texas at Austin, October 1958.
Maxwell, R. A., Mineral Resources of South Texas (Region served through
the Port of Corpus Christi), Report of Investigations -, No. 43,
Bureau of Economic Geology, University of Texas at Austin,
March 1962.
Patty, T. S., Geology of Central Texas Lime Sources (TP 6-68X) Texas
Highway Department, August 1968.
Reyna, For Jenaro Gonzale'z. "Riqueza Minear y Yacimientos Minerales
de Mexico'1. Tercera Edicion, Congreso Geologico Internacional, XX
Sesion, Mexico, 1956.
Reyna, For Jenaro Gonzalez. "Situacion Actual de la Industria Nacional
del Cenento - Nuraero de plantas y Sudistribucion Geografica-".
Mineral Trade Notes, Vol. 63, No. 4, Oct. 1966.
Reyna, For Jenaro Gonzale'z. "Los Recuros Minerales de Mexico". Consejo
de Recursos Naturales no Renovables. Mexico, D. F., 1969.
Rodda, R. U., W. L. Fischer, W. R. Payne, and D. A. Shofield, Limestone
and Dolomite Resources, Lower Cretaceous Rocks Texas, Report of
Investigations - No. 56, Bureau of Economic Geology, University of
Texas at Austin, January 1966.
The Mineral Industry of Mexico, "Productores, Principales Exportadores
e Importadores1". Directorio de Empresas Mineras No Metalicos.
Tomo II. Mexico, D. F., 1972.
20
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The Mineral Industry of Mexico, Reprint from the 1972 Bureau of Mines
Mineral Yearbook, United States Department of the Interior.
The Mineral Industry of Texas, Reprint from the 1972 Bureau of Mines
Mineral Yearbook, United States Department of the Interior.
21
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APPENDIX
TEXAS LIMESTONE PRODUCERS
JS7C17<>
Company
Address
County
Contact
Comment
Austin White Lime, Co.
McDonough Bros.. Inc.
Round Rxk Lime Co.
Texas Lime Co.
U. S. Gypsum Co.
Whitestone Lime Co.
McNeil. Texas
78651
Fredericksburg Rd.
Route 8. Box TO.
San Antonio. Texas
78228
P.O. Box 218
Round Rock. Texas
78664
P.O. Box 851
Cleburne. Texas
76031
101 South Wacker Dr
Chicago, Illinois
60606
Cedar Park, Texas
Travis
Bexar
Hill
Williamson
Johnson
Comal
Harris
Williamson
Mr. Jerry Hurta
(512-255-3646)
Mr. Kerner
(512-696-8500)
( 512-255-3611)
(817-645-6680)
-Two operational quarry sites located north of theMcNeill plant
-Third quarry two miles east of McNeill
-Chemical analysis shows high quality limestone -
CaCOj varies from 97% - 99.5*
CaO averages 55%: negligible magnesium present
-Floor of first 30' level contains massive chert beds, followed
by dolomite deposits
- Production began in 1968
-Operations of two large quarry sites along 1H10 one mile north
of FM1604 and 15 miles north of San Antonio. Lime plant is
located east of the quarry area
-Quarry is located in the fault zone complex of the Balcones
-Mainly quarry Edwards limestone
Chemical composition - average CaCG, - 99%
- Layers of chert nodules
-Produces agricultural limestone, chemical and industrial stone
-Hill county quarry located 1 mile south of H174, 4 miles west of Blum
- Comanche and Edwards Formation - Edwards limestone makes
up principle quarry stone - which is a complex fossilized reef -
Fossils contain Fe20, & Si02 - and numerous calcite crystal
deposits are found within the rocks
-Williamson County quarry
- 2 non -operating quarry sites - all crushed stone used for
kiln feed for both sites is trucked from Snead Quarry at
Georgetown
- No overburden problem
- Numerous interbedded layers of Si02 and dolomite/limestone
- Moderate fossil content
- Numerous cavities and veins dissect quarry face, filled with
calcite crystals
-Two operational plants, in 1968 only one plant was in use -
produces hydrate and quicklime - shipment by truck or rail
- The city plant is located 12 miles west of Cleburne - major production
is agricultural lime, fillers, chemical and industrial process stone
-Cleburne (West) Plant - located 12 miles west of Cleburne on Park
Road 21. Johnson County began in 1961. Quarry face is approximately
35 feet high belonging to the Edwards limestone formation
- Minor stripping is needed to remove the overburden of 2-5' of
Kiamichi and Marl
- Quarry floor is composed of impure limestone from the
Comanche peak formation
- Location 2 miles southwest of Braunfels
- Shipment by ran or truck
-20 leet overburden 1 maximum overburden is 60' I
-35' section of ' purity' limestone
- Plant and quarry are located 1 mile southwest of Cedar Park on FM1431
-Mainly quarries Walnut Formation; little Comanche Peak & Edwards
-5 -6 feet overburden
-Average CaCOj content is 98* -99*
22
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Ikra. 7S12CS1
Company
Address
County
Contact
Comment
Barrett Industries
General Portland Cement Co.
Giflord-Hill SCo., Inc.
Lone Star Industries, Inc.
Parker Bros. &Co.. Inc.
Texas Crushed Stone Co.
Texas Industries, Inc.
Trinity Concrete Products
White Mine's, Inc.
2718 S.W. Military Drive
Box 21070
San Antonio, Texas
78221
2800 Republic Bank
Tower
Dallas. Texas
75201
P.O. Box 47127
P.O. Box 47327
Dallas, Texas
75247
P.O. Box 107
Houston, lexas
77001
P.O. Box 9345
Austin, Texas
78717
P.O. Box 146
Midlothian, Texas
76065
P.O. Box47524
Dallas, Texa<
75247
P.O. Box 500
Brown wood, Texas
76801
Bexar
Dallas
Tarrant
Wise
Burnet
Nolan
Calhoun
Ellis
Wise
Hudspeth
Coma)
Matagorda
Llano
Williamson
Ellis
Wise
Johnson
Wise
Brown. Uvalde,
Taylor
(512-651-65501
Mr. W. Alderete
(214-233-68651
Mr. J.R. Jones
(214-637-3860)
(214-827-7720)
Mr. W. R. Wotnack
(214-631-8640)
Mr. W.D. Bankston
(713-637-2222)
Mr. Dale Bryan
(512-863-5511)
Mr. John Radney
(214-775-3449)
Mr. Ned Finney
(214-638-4700)
(915-646-8526)
- No longer active mining
- Limestone quarried in Dallas County is mainly an Austin Chalk
- Limestone quarried in Tarrant County is a soft, sedimentary stone
- Typical chemical composition - 51.0% CaO. 1.0* MgO. 5.0% SKK
0.5%Alj03. 0.5%Fej03, O.OWMn^, 0.05%Na20. 0.15%K20.
L0142.0*
- Typical chemical composition - 96.46% CaC03, 0. 71% MgC03,
1. 09% SI02. 1.30% AlzOj, 0. 19% Fe^
- Numerous interbedded layers of Dolomitic limestone
-Typical chemical composition -53. 14% CaO. 0.64% MgO. 3.49% SiO?.
0.36%Al203> 0.40%Fe203, LOI 41.86%
- Main quarry is located northeast of San Antonio
- High pu rity stone ( 95-98% CaC03
-SiOj is usually less than 1%
- Dolomitic limestone
- Limestone quarried in Wise County is from the Pennsylvanian Age
- 98-99% CaC03
- Hill County quarries are Lower Cretaceous Formations
- CaO content averages -43%
- Interbedded Al^ viens
- Pure Dolomite formations
- Excellent outcrop region is in the Edwards Reef Complex Formation in
the Curshberg Lagoon
- Approximately 100 miles in diameter
-West of Interstate 35. south of Interstate 20 and northeast
of Interstate 10
23
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-77-029
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Sorbent Selection for the CAFB Residual Oil
Gasification Demonstration Plant
5. REPORT DATE
March 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
E.P. O'Neill, D.L. Keairns, and M.A. Alvin
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Westinghouse Research Laboratories
Pittsburgh, Pennsylvania 15235
10. PROGRAM ELEMENT NO.
E HE 62 3 A
11. CONTRACT/GRANT NO.
68-02-2142
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Task Final; 4/75-3/76
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES jERL-RTP project officer for this report is S. L. Rakes, Mail
Drop 61, 919/549-8411 Ext 2825.
16. ABSTRACT
The report gives results of evaluations of limestones from Texas and
Mexico as candidate sulfur sorbents for the chemically active fluid-bed (CAFB)
gasification demonstration plant at San Benito, Texas. Preliminary laboratory tests
show that three limestones quarried in Texas and one quarried in Mexico should be
suitable sorbents, based on availability, chemical characterization, physical charac-
terization, attrition behavior, and chemical reactivity as sulfur sorbents. Current
sorbent selection criteria are being refined.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Fluidized Bed Pro-
cessing
asification
lesidual Oils
Sorbents
Limestone
Desulfurization
Tests
Evaluation
Combustion
Air Pollution Control
Stationary Sources
CAFB
Chemically Active
Fluidized Bed
13B 08G
07D
13H,07A 14B
21D
11G
21B
B. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport!
Unclassified
21. NO. OF PAGES
26
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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