&EPA
INDUSTRIAL
ENVIRONMENTAL
RESEARCH
LABORATORY
FGD
QUARTERLY
REPORT
VOL. 3 NO. 1
Spring 1979
RESEARCH TRIANGLE PARK, NC 27711
IN THIS ISSUE
The FGD Quarterly Report summarizes recent developments in
EPA-sponsored and conducted activities in flue gas desulfurtzation
(FGD). This issue features the conclusions of a recently completed
project which evaluated the potential of dry sorbents and fabric fil-
tration for FGD. Also included in this issue are summaries of sev-
eral ongoing and completed studies in FGD sludge disposal.
The next issue of the FGD Quarterly Report will highlight the
Fifth FGD Symposium, held March 5-8 in Las Vegas, Nevada. The
Symposium provided an important opportunity for the exchange of
information on recent developments in FGD.
The FGD Quarterly Report is distributed without charge to
persons interested in FGD. Those wishing to initiate or cancel
their subscriptions to the FGD Quarterly Report may do so by
contacting the EPA Project Officer or Radian Project Director
named on page 7 of this issue. Any change of address should
also be reported.
DRY SORBENTS AND FABRIC FILTRATION EVALUATED FOR FGD
TRW, Inc., recently conducted an EPA-sponsored study of dry
sorbents for FGD applications. The results have been reported In
Evaluation of Dry Sorbents and Fabric Filtration for FGD (EPA-
600/7-79-005, see "FGD Reports and Abstracts"). Results indicate
that this process may represent a breakthrough in FGD technology
when applied to western power plants burning low sulfur coal. The
study recommends further pilot demonstrations of the dry
sorbent/baghouse process, especially at elevated temperatures in
the vicinity of 274°C (525°F).
Conventional baghouses have long been successfully used to
remove fine particles from flue gases generated by certain industrial
and combustion sources. In recent years, certain baghouse vendors
and natural resource companies interested in potential sulfur diox-
ide (SO]) sorbents have promoted the use of the baghouse as an
FGD device. SO, removal is accomplished by introducing pow-
dered, dry sorbent into the gas stream or by precoating the bag-
house fabric with sorbent. Several test programs have been
conducted by potential users and vendors of baghouses, fabrics,
and sorbent materials to prove the technical feasibility of the proc-
ess.
Early TRW and EPRI/Bechtel Studies
In the spring of 1976, TRW undertook a preliminary study of
the dry sorbent/baghouse FGD concept. The objectives of this
study were to:
• Gather and evaluate available data on dry scrubbing tech-
nology.
• Evaluate qualitatively the range of conditions in which dry
scrubbing is practiced.
• Discuss the states of development of the baghouse, fabrics.
and operating modes.
* Examine sorbent supply, waste disposal, and possible
regeneration.
• Define concept problems and knowledge gaps.
• Recommend future work necessary to assess completely the
prospects for the commercialization, range of applicability,
and impact of the concept.
At approximately the same time, the Electric Power Research Insti-
tute (EPRI) contracted with Bechtel Corporation for a study with
similar objectives. Both this study and the TRW/EPA study con-
cluded that, based on available information, the dry sorbent/bag-
house FGD concept could have considerable economic advantage
under certain geographic, process, and regulatory constraints.
EPA/TRW Evaluation of
Nahcolite/Baghouse Concept
The dry sorbent/baghouse required further evaluation before
expensive field testing. Consequently, EPA requested that TRW
conduct a more thorough study to include additional assessment of
sorbent costs, system capital costs, system operating costs, and dis-
posal costs. The basic objective of the study (EPA-600/7-79-005)
was to determine if the apparent economic advantage of the
concept would remain intact after independent third-party
evaluation, and if the economic and other advantages would be
sufficient to warrant further development of the process.
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FGO QUARTERLY REPORT/SPRING 1979
Costs were estimated for a base-case situation and compared
with those of the currently available limestone FGD system. It was
thus possible to determine if the dry sorbent/baghouse FGD
process represents a substantial breakthrough in FGD technology
and can be expected to attain commercial viability in the future.
Base-case conditions were selected after examining current trends
in boiler design, SO, removal requirements, and available exper-
imental data on dry sorbent performance. The conditions selected
for detailed economic evaluation were:
• A new 500 MW boiler.
* Western coal, containing 1 percent sulfur.
• A distance of 1200 krn (750) miles from nahcolite (raw
NaHCO,) supplies.
• A semi-arid region with the water table 30 m (100 feet) below
the surface.
• A baghouse temperature of 204 °C <400°F).
• An SO, removal of 70 percent.
Additional refinement of the conditions may result in a slightly
lower cost. However, any conditions that are site specific or too
narrow in application would be unrealistic, since the equivalent of
ten 500 MW-equivalent Installations would be required to support
one commercial-scale nahcolite mine. This represents
approximately 4 percent of the total power output of the committed
fossil-fueled generating plants for the period 1977-1986.
Sorbent Supply
Several materials have been suggested for use as a sorbent in a
dry sorbent/baghouse FGD system. These include nahcolite and
trona, the natural sources of sodium bicarbonate and sodium car-
bonate, respectively. Magnesium oxide and pure sodium bicar-
bonate are also potential sorbents. However, nahcolite has proven
to be the most reactive sorbent. Futhermore, it is the only sub-
stance that has been tested sufficiently to provide adequate mater-
ial performance data for a full-scale plant design. For these reasons,
nahcolite was the sorbent used in this feasibility study.
A major problem with the nahcolite/baghouse FGD concept is
that nahcolite is not currently mined in the U.S. This is not due to
any lack of nahcolite deposits; total recoverable reserves in north-
western Colorado alone are large enough to support even the most
widespread application of the nahcoiite/baghouse process to
boilers firing low sulfur coal. However, substantial capital is
required for opening a commercial-scale mine. In addition, a
minimum-sized mine — 900 Gg/yr (1 million tons/yr) — would
supply enough nahcolite for 10 FGD systems (500 MW equivalent
each). To obtain such a large commitment to a new concept, the
nahcolite/baghouse FGD process must show substantial economic
advantages compared to current technology for which supplies of
lime and limestone sorbent are readily available.
Waste Disposal
The study examined a number of techniques for disposal of the
mixed fly ash/sodium salt waste material generated by the
proposed process. These Included landfill, "at sea" disposal, mine
disposal, deep welling, brine ponds, and use in chemical processes.
Of the techniques examined, landfill appears to be reasonably inex-
pensive and the most readily applicable.
There is concern as to whether the highly soluble wastes from
the nahcolite/baghouse process can be disposed of in an environ-
mentally acceptable manner without some sort of treatment (for
example, conversion to calcium as in the dual alkali process). The
direct disposal process considered in the TRW study, which
warrants further Investigation, involves landfill designed specifically
to preclude groundwater, surface water, and rainfall from entering
the deposit of soluble waste material. Groundwater intrusion is pre-
vented through careful site selection, while surface water and rain-
fall are excluded by a combination of dikes and an impermeable
(butyl rubber) membrane placed over the landfill site. Landfill costs
were estimated at $0.01 /kg (S6/ton) of waste.
Economics
TRW prepared an independent cost estimate for a typical
commercial installation to determine if the nahcolite/baghouse
process could penetrate the commercial market after successful
completion of a development program. To the extent practical,
estimating procedures were used which were consistent with those
used by TV A (EPA-600/2-75-006, January 1975) in their costing of
commercial FGD processes. Independent estimates for sorbent
supply and waste disposal were prepared, and all costs were
adjusted to a 1977 basis.
To evaluate fully the cost impact of the nahcolite/baghouse
process, a cost projection was developed for the limestone FGD
process, the predominant method in use today. A valid comparison
of the nahcolite/baghouse and limestone FGD processes required
the same operating conditions. Both systems were applied to new
500 MW power plants in Wyoming; 1 percent sulfur coal with an ash
content of 10 percent was burned. Abo, both systems had particle
controls capable of meeting the Federal New Source Performance
Standard for participate matter of 0.04 g (0.1 Ib) paniculate
matter emitted per MJ (10* Btu) of heat input.
Base-case costs for the nahcolite/baghouse FGD process
included a capital cost of $46 per kW and an annual operating cost
of 0.72 mills per MJ (2.60 mills per kWh). This was 35 percent
lower than the TVA base-case limestone process costs, which were
computed to be $ 119 per kW and 1.13 mills per M J (4.08 mills per
kWh) for the capital costs and annual operating costs, respectively.
Even in view of variations in estimating procedures, the cost
differences between the two FGD systems are promising. This,
together with the fact that limestone scrubbing is considered one of
the most economical FGD systems, makes the nahcolite/baghouse
system appear quite attractive.
Applications of the dry nahcolite/baghouse process to high
sulfur coal-firing may not be economically competitive with lime-
stone scrubbing. This is because more than 40 percent of the
annual operating costs for nahcolite/baghouse systems is for sorb-
ent and waste disposal, compared with 3 percent for the limestone
scrubbing process.
Experimental data indicate that nahcolite utilization may
approach 100 percent if the baghouse is operated at about 274°C
(525°F). This potential improvement in utilization would decrease
the cost of sorbent and disposal by about 30 percent over the base-
case. However, the savings would be somewhat offset by the
increased capital costs associated with operation at higher flue gas
temperatures. The net effect could be an approximate 10 percent
reduction in the annual operating cost. This new cost Is expected to
be about 40 percent less than the annual operating COB! of the base-
case limestone system.
Recommendations
The results of the TRW study indicate that the nahcolite/baghouse
process demonstrates an economic advantage over other currently
available FGD technologies when applied to western power plants
burning low sulfur coal. Since the TRW analysis indicates that the
nahcolite/baghouse process becomes economically advantageous
when operated at temperature* in excess of those used for current
demonstrations, a pilot plant study at temperatures of 274°C Is
recommended to provide confirming technical and cost data.
Data from ongoing tests at Wheelabrator Frye, Inc., and
Superior Oil Co. should be examined when available. These results
are important in confirming the data used in developing the
assumptions for the TRW report. The ongoing tests may also pro-
vide additional data on nahcolite utilization rates that occur at
elevated temperatures.
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FGD QUARTERLY REPORT/SPRING 1979
FGD SLUDGE DISPOSAL STUDIES
A major facet of President Carter's National Energy Plan is a
dramatic increase in the use of coal to meet the Nation's energy
needs. As coal utilization increases, the substantial wastes pro-
duced by nonregenerable FGD systems will present a significant
disposal problem.
EPA is conducting more than 20 research projects to define
and evaluate environmentally sound disposal alternatives. Brief
descriptions of some of these ongoing and completed studies are
presented in the following paragraphs. Summaries of other sludge
disposal studies may be found in previous issues of ihe FGD Quar-
terly Report. This research is providing EPA with a sound base for
developing effective FGD sludge disposal criteria.
Feasibility of Producing and Marketing
By-Product Gypsum
The production of gypsum from FGD wastes is an alternative to
disposal in ponds or landfill. The potential use of by-product
(abatement) gypsum in existing markets has been evaluated in a
study conducted by the Tennessee Valley Authority (TVA) under an
Interagency Agreement with EPA (EPA-600/7-78-192, see "FGD
Reports and Abstracts"). The study focused on the market potential
for the wallboard products manufacturing industry, the dominant
user of gypsum. The wallboard industry uses 14.5 Tg (16 x 10' tons)
of gypsum each year, a rate triple that of the cement industry. Po-
tential applications in the cement industry, however, were also
considered.
The main objectives of the study were to:
• Identify supply and demand in the gypsum industry.
• Characterize present demand and projected growth of major
markets.
• Identify market entry problems and recommend strategies.
• Evaluate costs for gypsum producing FGD systems.
• Improve an analytic model for marketing investigations and
apply the model to determine optimum strategies both for
individual plants and the overall industry.
The study reached several conclusions concerning abatement
gypsum. One was that because of huge reserves of natural
gypsum, no major national interests would be served by subsidiz-
ing abatement production to stockpile gypsum. Furthermore,
because of the low value of natural gypsum, production of abate-
ment gypsum has limited potential. Another conclusion was that
gypsum production and marketing offer a limited economic
incentive to the utility industry. Gypsum production and
marketing do appear however, to be a viable alternative for rela-
tively new, small plants (generally smaller than 200 MW) where
the required SO, removal amounts to 18-27 Mg (20,000-30,000
tons) of sulfur annually.
The study concludes that cement plants offer the greatest
market potential for abatement gypsum. The market for the wall-
board industry is limited because most wallboard industries own
their own gypsum mines and are located closer to the gypsum
sources than to the power plants. This situation is favored by
present government regulations such as minerals depletion
allowances, and favorable freight rates.
The study recommends that, for planning future growth in
both the utility and gypsum industries, special situations should
be identified where production of abatement gypsum has good
economic potential. Furthermore, the results of the study should
be used by the cement industry to evaluate the availability of
cheaper raw materials. The cost models developed can be used
to evaluate compliance alternatives. This should be particularly
helpful in planning for new power plants and in evaluating the
effects of changing regulations.
Additional information is available from the EPA/IERL-RTP
Project Officer, J. W. Jones, (919) 541-2489 or (FTS) 629-2489.
Shawnee FGD Waste Disposal Evaluation
EPA, under a continuing contract with the Aerospace Corpor-
ation, has expanded a project (or evaluating disposal of FGD
sludges. The project, initiated in 1974, is being conducted at the
TVA Shawnee Steam Electric Plant in Paducah, Kentucky. The
sludges are obtained from prototype scrubbers which use both lime
and limestone sorbents.
The project is examining three disposal alternatives: (1) two
control ponds of untreated sludges, (2) three ponds containing
chemically treated sludges, and (3) three ponds equipped with
underdrain systems and containing untreated sludges. The ponds
are all on soil which has low permeability and a deep water table.
In the past 2 years, two of the ponds, one chemically treated
and one untreated and underdrained, have been retired to
determine if the disposal areas can be reclaimed. Retirement con-
sisted of draining off the surface water, filling a nd tamping test
coring holes, filling the ponds with dirt, and compacting and
grading. The top cover has been planted with grass to minimize
erosion. Results have shown that this type of cover can successfully
prevent rainwater from reaching the ponded sludge and that the
disposal area can be reclaimed for other uses. Plans are underway
to slope the pond overburden and to plant trees to determine the
minimum overburden depth required to support larger vegetation.
During the past several months, two additional disposal sites
have been constructed in order to study two types of gypsum filter
cake waste materials. The first of these sites, now being filled, will
contain over 458 m! (600 yd1) of filter cake with ash. This waste
material contains adipic acid, which is being used as a scrubber
additive. At this site, studies will investigate the compactibility of
gypsum filter cake and its usefulness as a landfill material. The
second site, which should be filled early in 1979, will contain
gypsum filler cake with ash (no adipic acid), produced under scrub-
ber conditions simulating operating parameters at TVA's Widows
Creek power station.
Project results to date are:
• Chemical treatment reduces the initial concentration of total
dissolved solids (TDS) in sludge leachates to approximately
half that of the input liquor, whereas the initial concentration
of total TDS in leachates of untreated sludge approximates
that of the input liquor.
• Chemically treated sludges consistently show bearing
strengths of 207 MPa (300 psi) or greater. Load bearing
strengths exceeding 24 MPa (35 psi) can be achieved with
untreated sludges by under draining and have reached values
exceeding 207 MPa in some instances.
• Groundwater contamination in the vicinity of both treated
and untreated ponds has not been observed during the 4-year
test period.
• Runoff from gypsum filter cake contains concentrations of
total suspended solids which consistently exceed 30 mg/l,
thereby indicating a requirement for continuous control of
gypsum runoff at operational sites.
• Disposal cost estimates in mills per megajoule( July 1977
dollars) for ponding on indigenous clay, ponding with liner
added, and chemical treatment are 1.98 (0.55/kWh), 2.88
(0.80/kWh), and3.78(1.05/kWh), respectively, for a 1000
MW station burning eastern coal.
Additional information may be obtained from the EPA/IERL-
RTP Project Officer, M. C. Osborne, (919) 541-2489 or (FTSl 629-
2898. A recent report, Disposal of Flue Gas Cleaning Wastes:
EPA Shawnee Field Evaluation — Second Annual Report (EPA-
600/7-78-024), summarizes the latest findings of this study. A
detailed description of EPA's Shawnee Test Facility is presented
in the FGD Quarterly Report, Volume 2, Number 4.
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FGD QUARTERLY REPORT/SPRING 1979
Environmental Assessment of Coal Waste
Disposal in Ocean Reefs
In the face ot increasing costs and pollution problems
associated with land disposal of boiler plant and FGD wastes,
government and industry have organized to investigate an "at sea"
disposal alternative. The method involves placing blocks of treated
FGD wastes on the continental shelf. Prior to disposal, the wastes
are chemically stabilized and compacted in a process developed by
IU Conversion Systems, inc.
In a recent pilot study conducted by the Marine Sciences
Research Center (MSRC) of the State University of New York
(SUNY). a small reef was constructed of the blocks and placed in
Conscience Bay, Long Island. Preliminary results indicate no
adverse environmental effects; indeed the surfaces of some blocks
are being colonized by diverse communities of aquatic organisms.
An additional pilot study ot this disposal alternative was carried
out by Arthur D. Little, Inc. The study, An Evaluation of the
Disposal of Flue Gas Desulfurmation Wastes in Mines and the
Ocean: Initial Assessment (EPA-600/7-77-051), concluded that
this method of at sea disposal is a very promising disposal option
and recommended further research.
On the basis of the results from these pilot studies, the New
York State Energy Research and Development Authority
(NYSERDA) initiated a cooperative venture by a diverse multi-
disciplinary group of industrial and university scientists, as well as
New York State agencies. The goal of the venture is a large-scale
demonstration of coal waste disposal on the continental shelf. The
principal investigators are MSRC, the Department of Materials
Science of the State University of New York, and IU Conversion
Systems, Inc. Other investigators are the Institute for Energy
Research and the New York State Department of Environmental
Conservation (DEC). The project is funded by EPA, the U. S.
Department of Energy, the Electric Power Research Institute,
NYSERDA, and the Power Authority of the State of New York.
A coal waste reef consisting of 700 blocks (0.76 rn* or 1 yd*
each) of stabilized scrubber sludge and fly ash will be placed in the
open ocean 6 km (4 mites) off Fire Island. The reef will be
constructed in August 1979. The site, which is 1.6 by 0.2 km(10x
0.13 miles), has been designated for artificial reef construction by
DEC; various solid materials have already been placed to form an
artificial fishing reef.
Equal numbers of blocks with two compositions will be used —
1:1 and 3:1 (dry weight) fly ash to scrubber sludge. During the
study, experiments will also be carried out with a number of smaller
blocks (0.028 rn'orl ft!) composed of stabilized refuse ash at a low
SO,:SO, (high sulfite) ratio.
IU Conversion Systems, Inc. will provide the blocks obtained
from the Duquesne Power and Light Co., Elrama Station, located
just outside Pittsburgh, Pennsylvania. The Elrama plant has a 510-
MW-equivalent lime scrubbing FGD system. The treated blocks will
be trucked to a docking facility near New York City. They will then
be transferred to a barge and taken to the reef site.
The focus of the 5-year investigation will be on the following
environmental and biological considerations:
• The biological acceptability of scrubber waste blocks in the
ocean.
• The colonization of the blocks by attached and motile
organisms, and changes in community structure.
• Habitation by fish.
• The uptake of block components (heavy metals, for example)
by the colonizing organisms and their incorporation into
marine food chains.
* The effect of the block materials on water and sediment
properties.
The biological data will be used to develop parameters for
comparison with biological colonization processes on natural
surfaces and on conventional artificial (i.e., concrete) fishing reefs.
The following engineering and physical considerations will also
be investigated:
* The erosion, corrosion, and fouling characteristics of the
blocks.
* The strength of block materials and the effects of aging.
• The possible deterioration and movement of the reef over a
period of years.
* The processes producing sediments from the block
materials.
Results of the program will provide a basis for assessing the impact
and environmental acceptability of large-scale disposal of stabilized
coal wastes in the ocean.
For additional information contact the EPA/IERL-RTP Project
Officer, J. W. Jones, (919) 541-2489 or (FTS) 629-2489.
UTILITY AND INDUSTRIAL SURVEYS INCORPORATE NEW ECONOMIC DATA
The EPA Utility FGD Survey is prepared every other month by
PEDCo Environmental Specialists, Inc. PEDCo also issues the
newer EPA Industrial Boiler FGD Survey on a quarterly basis.
Reported economic data and, more recently, standardized capital
and annual cost figures have been incorporated into the utility
survey to provide more meaningful economic data on FGD. This
information is also being added to the industrial survey.
The cost of FGD systems is an area of intense interest. Both
surveys have included this information in appendices. However,
until recently the cost appendices consisted entirely of data reported
by system operators with little or no interpretation by PEDCo.
In 1978 PEDCo conducted a detailed cost analysis of all
utilities having operational FGD systems. Available cost data were
gathered and analyzed. The data analysis focused on adjusting
individual cost estimates to a common cost basis. To the extent
possible, all cost adjustments were made using a standard cost
breakdown developed by PEDCo. The data were adjusted to current
dollar values.
As reported recently (EPA-600/7-78-051d, see "FGD Reports
and Abstracts"), the average reported capital cost for 27 operating
FGD units was $78/kW; the adjusted figure was $96/kW. The
average annual operating cost for the same plants was
1.3 mills/MJ (4.8 mills/kWh), adjusted to 1.5 miils/MJ
(5.5 mills/kWh). However, individual costs for specific FGD
systems may be more valuable to an FGD plant designer In view of
the statistically few FGD plants in operation.
By placing all of the FGD plants on a common cost basis, the
survey eliminates much of the existing confusion concerning the
reported data and permits comparisons of the various types of FGD
plants.
Further information on the EPA Utility FGD Survey is available
from the EPA/IERL-RTP Project Officer, N. Kaplan, (919) 541-
2556 or (FTS) 629-2556. For more information on the EPA
Industrial Boiler FGD Survey, contact the EPA/IERL-RTP Project
Officer, R. M. McAdams, (919) 541-2915 or (FTS) 629-2915. (See
also "FGD Reports and Abstracts" in this issue.)
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FGO QUARTERLY REPORT/SPRING 1979
FGD REPORTS AND ABSTRACTS
Each report with an NTIS number can be ordered from
NTIS. The cost of paper copies varies by page count ($4.00
minimum); microfiche copies are $3. Payment must accompany
order. The address is:
National Technical Information Service
U. S. Department of Commerce
Springfield. Virginia 22161
(703) 557-4650
(FTS) 557-4650
EPA/IERL-RTP reports are available, as supplies permit,
through lERL-RTP's Technical Information Service (T1S). The
address is:
Technical Information Service (MD-64)
Industrial Environmental Research Laboratory
U, S. Environmental Protection Agency
Research Triangle Park, NC 27711
(919)541-2216
(FTS) 629-2216
SYSTEM EVALUATION
Evaluation of Dry Sorbents and Fabric Filtration for
FGD
S. J. Lutz, R. C. Christman, B. C. McCoy, S. W. Mulligan, and
K. M. Slimak, TRW, Inc., Durham, North Carolina, January 1979.
EPA-600/7-79/005. (NTIS No. PB 289 921.) EPA Project Officer:
C. J. Chatlynne, IERL-RTP.
The report gives results of a study to assess the use of baghouses
(fabric filters) to control air pollutant emissions (particularly SO,)
from large utility combustion sources. The assessment included
sorbent costs, and system capital, operating, and disposal costs.
SO, would be removed by introducing powdered dry sorbent into
the gas stream or by precoating the baghouse fabric with sorbent.
The objective of the study was to determine if the apparent
economic advantage exhibited by the concept would remain intact
after independent third-party evaluation and if the economic (and
other) advantages are sufficiently large to warrant further
development of the process at field installations. The evaluation
shows that the dry sorbent baghouse FGD process exhibits an
economic advantage when compared with current lime and
limestone scrubbing technology when applied to Western power
plants burning low sulfur coal. Further demonstrations on the pilot
plant scale have been recommended, particularly at high
temperatures. The need for extensive user (electric utility)
commitment, in order to justify the considerable capital investment
needed to open a commercial-scale sorbent (nahcolite) mine, may
represent the greatest barrier to commercialization of the process.
Double Alkali Flue Gas Desulfurization System
Applied at the General Motors Parma, Ohio
Facility: Capsule Report
Arthur D. Little, Inc., January 1977. EPA-625/2-78-016. (NTIS
No. PB 279 212.) EPA Project Officer: N. Kaplan, IERL-RTP.
This report describes the results of the test program at Parma. In
summary, the system has demonstrated a consistent 90% SO,
removal capability. Operating reliability has improved during the
test program after some difficulties, principally in the early
months of operation. The construction cost of General Motors'
Double Alkali System was $3.2 million, reported in 1975 dollars.
A more detailed description of the test program results are
available in the EPA report, "Evaluation of the General Motors
Double Alkali SO, Control System," January 1977 (EPA-600/7-
77-005) (NTIS No. PB 263 469).
Demonstration/Evaluation of the Cat-Ox Flue Gas
Desulfurization System: Final Report
R. Bee, R. Reale, and A. Wallo, The Mitre Corporatkm/Metrek
Division, McLean, Virginia, March 1978. EPA-600/2-78/063.
(NTIS No. Unavailable.) EPA Project Officer: C. J. Chatlynne,
IERL-RTP.
The report gives a comprehensive summary of the experience
gained and the problems encountered during the Cat-Ox
demonstration program. The report outlines the process design
and construction, as well as operating experience and problems.
Test results and conclusions derived from baseline testing,
acceptance testing, ESP testing, transient testing, and a number
of special tests and studies associated with the system are
reported.
RESEARCH AND DEVELOPMENT
Characterization of Carbide Lime to Identify Sulfite
Oxidation Inhibitors
L. J. Holcombe, and K. W. Luke, Radian Corporation, Austin,
Texas, September 1978. EPA-600,'7-78/176. (NTIS No. PB 286
646.) EPA Project Officer: Julian W. Jones, IERL-RTP.
The report gives results of a study of carbide lime — a by-product of
acetylene manufacture, primarily calcium hydroxide — used in a
flue gas desulfurization (FGD) system at Louisville Gas and Electric
(LGE). The study was undertaken to: identify sulfite ion oxidation
inhibitors in carbide lime, and develop an analytical method for
sulfite that avoids the interferences observed in analyzing scrubber
liquors from LGE's FGD system. Thiosulfate was identified as the
oxidation inhibitor in carbide lime; it was also identified (along with
other reduced sulfur species) as a source of interference in !he
iodine titration method used at LGE for sulfite analysis. Bench-
scale tests verified the presence of thiosulfate as a major inhibition
to sulfite oxidation in simulated scrubber liquors. This means that
the low oxidation rate (e.g., that reported at LGE with carbide lime)
results in greatly reduced tendency to calcium sulfate (gypsum)
scaling, therefore a greatly improved FGD system reliability. The
amount of thiosulfate required for scale-free scrubber operation is
unknown. However, to bring the thiosulfate level of commercial
lime up to that found in carbide lime would cost $1.50 per ton of
lime (using sodium thiosulfate pentahydrate at $12 per 100
pounds). The ion chromatograph was found to be the best
analytical tool for determining sulfite concentrations in carbide lime
liquors.
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FGD QUARTERLY REPORT/SPRING 1979
SYSTEM BY-PRODUCTS
Feasibility of Producing and Marketing By-Product
Gypsum From SO2 Emission Control at Fossil-Fuel-
Fired Power Plants.
J. M. Ransom, R. L. Torstrick, and S. V, Tomlinson, Tennessee
Valley Authority, Muscle Shoals, Alabama, October 1978. EPA-
600/7-78-192. (NT1S No. PB 290 200.) EPA Project Officer: J. W.
Jones, 1ERL-RTP.
The major purpose of this study was to identify fossil-fuel-fired
power plants that might, in competition with existing sources of
crude gypsum and other power plants, lower cost of compliance
with SO, regulations by producing and marketing abatement
gypsum. In the eastern part of the U.S., gypsurn production was
shown to have a limited but important potential to lower cost of
compliance by power plants. Gypsum consumption was projected
to amount to 2 million tons in wailboard use and 3 million tons in
cement; total value of sales in 1978 was estimated at $124.4 million
in that region.
Total potential gypsum production by 113 Eastern U.S. steam
plants requiring flue gas desulfurization for compliance was 27
million tons. For about 90% of the potential abatement gypsum
production, the cost difference between producing gypsum and
producing conventional sulfite sludge by limestone scrubbing is
greater than the estimated cost of mining natural gypsum.
However, 30 power plants (generally smaller than 200 MW) with
small annual outputs were identified that could reduce compliance
cost by producing and marketing abatement gypsum. The 30 plants
would replace 2.23 million tons of crude gypsum at 93 demand
points (92 cement plants and 1 wailboard plant). Of the gypsum
replaced, 74% is imported. Total first-year saving to steam plants is
SI 1 million and about $2 million is saved by the gypsum industry.
Production of gypsum instead of sludge as a means of compliance
with SO, regulations was shown to be suited to small new plants
and may well fill an important role in a total program of by-
product marketing by steam plants in meeting compliance.
Control of Waste and Water Pollution from Coal-
Fired Power Plants: Second R & D Report
P. P. Leo and J. Rossoff, The Aerospace Corporation, El
Segundo, California, November 1978. EPA-600/7-78-224. (NT1S
No. PB 291 396.) EPA Project Officer: J. W. Jones, IERL-RTP.
The report is the second of a series summarizing and assessing
the state of research and development in the fields of flue gas
cleaning waste treatment, utilization, and disposal, as well as
water reuse technology for coal-fired utility power plants.
Significant areas treated include: coal-pile drainage; ash
characterization and disposal; chemical and physical properties
and leaching characteristics of treated and untreated flue gas
desulfurization (FGD) wastes; field evaluations of treated and
untreated waste disposal; physical and chemical properties of
gypsum produced from FGD systems; cost estimates for
producing and disposing of FGD gypsum; potential use of FGD
wastes in fertilizer production; the economics of alumina
production; and power plant water recycle, treatment, and reuse.
EPA-600/7-76-018 was the previous report in this series.
Utilization of Lime/Limestone Waste in a New
Alumina Extraction Process
E. P. Motley and T. H. Cosgrove, TRW, Inc., Redondo Beach,
California, November 1978. EPA-600/7-78-225. (NT1S No.
290 105.) EPA Project Officer: J. W. Jones, IERL-RTP.
The report gives results of a preliminary process design and
economic evaluation of a process for using lime/limestone scrub-
bing wastes as a source of calcium in the extraction of alumina
(for use in aluminum production) from low grade domestic ores
such as clays and coal ash. The other principal process feed-
stocks are soda ash and coal. The products are alumina,
elemental sulfur, and dicalchtm silicate, an alternate feedstock in
the manufacture of portlartd cement. The conceptual plant is
located next to a 1000 MW coal-burning power plant which
generates > 1 million tons per year (tpy) of lime/limestone
scrubber wastes. The required selling price for the alumina
produced at 10% discounted cashflow would be $195-370 per
ton, depending on the credit for sludge removal, exclusive of
cement manufacture. If the alumina plant were co-located with
an 860,000 tpy Portland cement plant selling cement at $50 per
ton, the required alumina selling price wouM be $27-221 per ton.
Based on the current market price for alumina ($160 per ton),
the portland cement plant appears to be necessary to make the
process viable. In addition to the scrubber wastes, the process
requires 12,000 tpy of soda ash, 300,000 tpy of clay, and
273,000 tpy of coal to produce 70,000 tpy of alumina, 156,000
tpy of sulfur, and 625,000 tpy of dicalcium silicate (used to produce
860,000 tpy of Portland cement).
FGD AND ALTERNATIVE TECHNOLOGIES
Status of Flue Gas Desulfurization Applications in
the United States: A Technological Assessment
Federal Power Commission, Washington, D.C., July 1977. (NTIS
No. PC A23/MF A01.)
The removal of sulfur compounds from the stack gases of coal-
burning, electric power plants has been a national issue lor the
past decade. Desulfurization of flue gases by devices commonly
referred to as "scrubbers" is a major approach to the problem but
their use has been the subject of continuing controversy. Still
unresolved are questions concerning their suitability for
commercial utility operations, the relative merits of one design
over another, the feasibility and costs of sludge disposal for
"throwaway** systems, the outlook for improved second
generation systems, and, perhaps most important, whether the
complex chemistry and health effects of airborne sulfur oxides are
sufficiently well understood to be sure that heavy investments in
scrubbers will produce the desired results. Definitive answers to
these questions do not yet exist, yet decisions must be made.
This report is intended to be a basic reference and Information
source. The report does not attempt to provide ulitmate
conclusions, although there are a number of specific findings. It
is primarily a descriptive assessment. Alternative technologies for
meeting air pollution control regulations are discussed including:
use of low-sulfur conforming coal; coal washing; supplementary
control systems and tall stacks; solvent-refined coal; and coal
gasification and fluidized-bed combustion. The potential of flue
gas desulfurization and these alternative technologies are
discussed. Regulatory pressures relative to the installation of
scrubbers are the result of the administrative and judicial
implementations of the Clean Air Act. The financial costs of
scrubber installations are compared with the most commonly
applied alternative: burning western low-sulfur coal.
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FGD QUARTERLY REPORT/SPRING 1979
SYSTEM SURVEYS
EPA Utility FGD Survey: April-May 1978; June-July
1978
B. Laseke, M. Meiia, M. Smith, and W. Fischer, PEDCo
Environmental, Inc., Cincinnati, Ohio, September 1978;
November 1978. EPA-600/7-78-051c and 051d. (NT1S Nos. PB
286 707 and PB 288 299.) EPA Project Officers: N. Kaplan,
IERL-RTP; and J. C. Herlihy, DSSE.
The reports are updated supplements to EPA-600 78-051 a and
should be used In conjunction with it. They present a survey of
utility flue gas desulfurization (FGD) systems In the U.S.,
summarizing Information contributed by the utility industry,
process suppliers, regulatory agencies, and consulting
engineering firms. Systems are tabulated alphabetically, by
development status (operational, under construction, in planning
stages, or terminated operations), by utility company, by process
supplier, by process, by waste disposal practice, and by
regulatory class. They present data on system design, fuel sulfur
content, operating history, and actual performance. They discuss
problems and solutions associated with the boilers and FGD
systems. Process flow diagrams and FGD system economic data
are appended to the reports.
EPA PROJECT OFFICERS FOR CURRENT FGD RD&D PROJECTS
Robert H. Borgwardt, MD-65
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2336
(FTS)629-2336
Ted G. Brna, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2683
(FTS)629-2683
C. J. Chatlynne, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS)629-2915
Julian W. Jones, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2489
(FTS)629-2489
Norman Kaplan, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2556
(FTS)629-2556
Robert E. Landreth
USEPA, MERL-Cinn
26 West St. Claire St.
Cincinnati, OH 45268
Phone: (513)684-7871
(FTS)684-7871
R. Michael McAdams. MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS)629-2915 ;
i. David Mobley, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS)629-2915
Michael C. Osborne, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2898
(FTS>629-2898
Warren D. Peters, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS)629-2915
Wade H. Ponder, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS)629-2915
Mkhael H. Rouller
USEPA, MERL-CInn
26 West St. Claire St.
Cincinnati, OH 45268
Phone: (513)684-7871
(FTS)684-7871
Donald E. Sannlng
USEPA, MERL-CInn
26 West St. Claire St.
Cincinnati, OH 45268
Phone: (513)684-7871
(FTS)684-7871
John E. Williams, MD-61
USEPA. IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2483
(FTS (629-2483
The FGD Quarterly Report is part of a comprehensive EPA Engineering Application/Information Transfer (EA/IT) Program on flue gas
desulfurization (FGD). The report is designed to meet four objectives: (1) to disseminate information concerning EPA sponsored and conducted
research, development, and demonstration (RD&D) activities in FGD; (2) to provide progress updates on selected ongoing contracts; (3) to
report final results of various FGD studies; and (4) to provide Interested persons with sources of more detailed information on FGD. The EA/IT
program is sponsored by EPA's Industrial Environmental Research Laboratory, Research Triangle Park, North Carolina (IERL-RTP).
The FGD Quarterly Report is prepared by Radian Corporation under EPA Contract No. 68-02-2608. The EPA Project Officer is R. Michael
McAdams (address above). The Radian Project Director is Elizabeth D. Gibson, P.O. Box 9948, Austin, Texas 78766 (512) 454-4797.
Contributors to this issue were E, D. Gibson, P. M. Jeans, and C. L. McCarthy.
The Report is distributed, without charge, to persons Interested In FGD. Those wishing to report address changes, or initiate or cancel
their free subscriptions to the FGD Quarterly Report may do so by contacting the EPA Project Officer or Radian Project Director named above.
The views expressed in the FGD Quarterly Report do not necessarily reflect the views and policies of the Environmental Protection Agency.
Mention of trade names or commercial products does not constitute an endorsement or recommendation for use by EPA.
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ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, N. C. 27711
Attention: R.M. McAdams (MD-61)
OFFICIAL BUSINESS
Penalty For Private Use $300
An Equal Opportunity Employer
Postage And Fees Paid
Environmental Protection Agency
EPA - 335
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