United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S9-84-017 Sept. 1984
&EPA Project Summary
Proceedings: Eighth Symposium
on Flue Gas Desulfurization,
New Orleans, LA, November
1983
Franklin A. Ayer
The symposium provided a forum for
the exchange of technical developments
and regulatory information on flue gas
desulfurization (FGD) systems and
processes applicable to utility and in-
dustrial boilers. The keynote address
described the National Acid Precipita-
tion Assessment Program. Other open-
ing-session presentations were on the
status of air quality legislation/regula-
tions, the status of solid waste regula-
tions, and trends in commercial applica-
tion of FGO technology. Subsequent
sessions dealt with FGD economics,
materials of construction, dry furnace
absorbent injection, dual alkali FGD,
flue gas treatment (combined SO,/NO»
removal), FGD chemistry, the architect-
engineer's role in FGD applications
(panel discussion), limestone/organic
acid, waste disposal/utilization, and
dry FGD systems. Participants repre-
sented electric utilities, equipment and
process suppliers, state environmental
agencies, coal and petroleum suppliers,
EPA and other Federal agencies, and re-
search organizations.
Julian W. Jones, Industrial Environ-
mental Research Laboratory, U.S.
Environmental Protection Agency,
Research Triangle Park, NC, and Thomas
M. Morasky, Coal Combustion Systems
Division, Electric Power Research
Institute, Palo Alto, CA, were Sympo-
sium Chairmen.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory. Research Triangle
Park, NC. to announce symposium pre-
sentations that are fully documented in
a separate document of the same title
{see ordering information at back).
Session 1. Opening Session
Julian W. Jones, Chairman
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Welcome and Introduction
Michael A. Maxwell
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Stuart M. Dalton
Coal Combustion Systems
Division
Electric Power Research Institute
Palo Alto, CA
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Introduction of Keynote
Speaker
Frank T. Princiotta
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Keynote Address: National
Acid Precipitation Assessment
Program: Status and Outlook
J. Christopher Bernabo
National Acid Precipitation
Assessment Program
722 Jackson Place, NW
Washington, DC
The National Acid Precipitation Assess-
ment Program is designed to successive-
ly improve our understanding of the
causes and effects of, and possible
solutions to, the acid rain problem. The
Program includes research, monitoring,
and assessment activities that emphasize
the timely development of a progressively
firmer scientific basis for decision making
by the Congress, regulatory agencies,
private sector managers, environmental
groups, and the public. The National
Program consists of over 200 projects
and hundreds of scientists in government,
academia, and the private sector.
The Status of the Clean Air
Act Reauthorization
Sheldon Meyers
Office of Air Quality Planning and
Standards
U.S. Environmental Protection
Agency
Washington, DC
The remarks opened with the state-
ment, "The Clean Air Act Reauthorization
is as yet unenacted." Light was shed on
why the Congress had not acted on the
reauthorization so far, and some reasons
were suggested for the assignment's
being so difficult. Some of the areas of the
Act were identified as causing EPA
problems, and some elements were listed
which should be included in any discus-
sion of a reauthorization. In closing it was
pointed out that any discussion of
problems should not obscure the fact
that, despite its complexity, the Clean Air
Act has worked: the public health is better
served now than it was before the Act
became law in 1970.
The Resource Conservation and
Recovery Act: Current and
Projected Regulations
Stephen A. Lingle
Office of Solid Waste
U.S. Environmental Protection
Agency
Washington, DC
This was a verbal presentation; no
abstract or paper was submitted.
Trends in Commercial
Application of FGD
Technology
Bernard A. Laseke, Jr.,* Michael
T. Melia
PEDCo Environmental, Inc.
Cincinnati, OH
Norman Kaplan
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
PEDCo Environmental, Inc. has been
monitoring and reporting on the status of
utility FGD technology since 1974. From
1974 to 1982, this effort was supported
by the U.S. EPA under the direction of the
Industrial Environmental Research Lab-
oratory-RTP. Starting this year, this
effort is now jointly sponsored by EPA and
the Electric Power Research Institute
(EPRI). Project direction from EPRI is
provided by the Coal Combustion Systems
Division.
Information for this program is obtained
by visits to plants having operational FGD
systems and through regular contacts
with the owner/operator utilities who are
presently operating or planning FGD
installations. Supplemental information
is also solicited from FGD system and
equipment suppliers, design/engineering
firms, research organizations, and regu-
latory agencies.
The information collected in this
program is stored in the FGD Information
System (FGDIS), which is a collection of
computerized data base files containing
descriptive, design, performance, and
cost data for all the FGD systems
identified in FGDIS. FGDIS has the dual
capability of generating periodic survey
reports (now available through EPRI) as
well as permitting immediate access to
•denotes speaker
the data files via remote terminal. This
latter feature allows private and govern-
ment users to access FGDIS directly ai
any time, to conduct custom-designec
data analyses, examine detailed data that
may be too specific to be conveniently
included in the survey report, or review
information that has been loaded into the
system but not yet published.
This paper summarizes the status o
FGD technology as of June 1983 an<
highlights the status of the electric utilif
power industry and projected growth o
coal-fired power generation, the presen
status and future trends in the growth o
FGD, developments in system design am
application, current operating experience
and costs.
As of June 1983, 114 FGD systems ii
service represented 45,750 MW (gross
of equivalent power generating capacity
Another 100 systems representin
59,324 MW were under construction c
planned. Approximately 16 percent of th
present coal-fired generating capach
is controlled by FGD. This figure i
projected to rise to 34 percent during th
next 10 years.
Session 2. Economics
Thomas M. Morasky, Chairman
Coal Combustion Systems
Division
Electric Power Research Institul
Palo Alto, CA
Computer Economics of
Physical Coal Cleaning and
Flue Gas Desulfurization
Charles R. Wright,*Terry W.
Tarkington
Tennessee Valley Authority
Muscle Shoals, AI
James D. Kilgroe
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
A computer model that simulates 1
performance and calculates the econo
ics of a coal-cleaning process, a F(
process, and a combination of the t
processes for electric utility boilers T
been developed by the Tennessee Val
Authority (TVA) under sponsorship of
U.S. Environmental Protection Agei
(EPA). The model also determines ot
economic benefits and penalties
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overall power plant operations that are
associated with the use of cleaned coal.
The model is described and its use is
illustrated for selected design and
economic premises. The present status of
the model is assessed and possible future
studies are discussed. The illustrative
examples show that in some instances a
combination of coal cleaning and FGD for
SOa emission control can be more
economical than FGD alone.
For the cases studied, it was found that
the use of coal cleaning in combination
with FGD can have a varied effect on the
levelized annual cost of power production.
This effect, which is dependent on the
coal and the specific operating conditions,
ranges from 0.5% increase to a 22.6%
decrease in those costs.
The methods used to determine many
of the other economic benefits and
penalties of coal cleaning are necessarily
general in nature because detailed data
relating specific coal properties*to boiler
performance and operating costs are
scarce. Thus, development and incorpor-
ation of more detailed and quantitative
data in the model would greatly increase
the usefulness of the model in assessing
overall economic effects of coal cleaning.
Economic Evaluation of FGD
Systems
Jack B. Reisdorf,* R.J. Keeth,
C.P. Robie, R.W. Scheck
Stearns-Roger Engineering
Corporation
Denver, CO
Thomas M. Morasky
Electric Power Research Institute
Palo Alto, CA
This paper estimates the cost of 17
throwaway and regenerable FGD systems
based on December 1982 cost and
technology. These systems were also
evaluated for operability, technical merit,
and commercial availability. The FGD
systems were evaluated for high sulfur
coal applications at a hypothetical 1000
MW (two 500 MW units) power plant in
Kenosha, Wl. This arbitrary reference
plant was selected to ensure consistent
comparisons, and to increase the relative
accuracy of the costs presented.
A flow sheet, material balance, equip-
ment list, system description, and utility
consumption list form the basis of each
FGD evaluation. Cost information was
obtained from process vendors, Stearns-
Roger information, and published reports.
Capital costs were estimated by factoring
costs of process equipment (i.e., an EPRI
Class II estimate). Operating costs were
estimated from reagent and utility
consumption. The levelized capital and
operating costs were developed using
EPRI's standard economic premises. The
costs reported in this study are estimated
within an absolute accuracy of ±30%.
However, since methodology, scope and
unit costs are consistent, the relative
accuracy between processes is about
±15%.
Estimating Procedure for
Retrofit FGD Costs
R.R. Mora, P.A. Ireland/ R.J.
Keeth
Stearns-Roger
Engineering Corporation
Denver, CO
Thomas M. Morasky
Electric Power Research Institute
Palo Alto, CA
A procedure has been developed for
utility engineers to estimate site-specific
FGD retrofit costs on existing power
plants. This procedure has been developed
for six FGD processes: limestone, lime
dual alkali, lime spray drying, limestone
forced oxidation, Wellman-Lord, and
Chiyoda 121. Economic results from the
calculation procedure include capital
cost, operating and maintenance (O&M)
costs, levelized cost, and cost per ton of
SOj removed.
Comparative Costs of SOs
Removal Technologies
John 0. Milliken
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
The costs of retrofitting four types of in-
plant S02 control technologies are
compared for a 500 MWpulverized-coal-
fired utility boiler. Technologies examined
are at various stages of commercialization
and market penetration, and include: (1)
fully commercial - limestone FGD, (2)
early commercial - adipic acid enhanced
FGD, (3) early commercial - lime spray
drying, and (4) developmental - limestone
injection multistage burners. Cost com-
parisons are made by process subarea, by
operating cost categories, by capital to
operating cost ratio, and by overall sulfur
removal effectiveness.
Session 3. Materials of
Construction
Charles E. Dene, Chairman
Electric Power Research Institute
Palo Alto, CA
EPRI Research on Corrosion
and Degradation of Materials
for FGD Systems
Barry C. Syrett
Electric Power Research Institute
Palo Alto, CA 94303
An EPRI survey of materials problems
in full-scale lime/limestone wet scrub-
bers in the U.S. revealed that the most
frequent and most critical failures oc-
curred in the outlet ducts and the stack,
but that a significant number of failures
also occurred in the prescrubbers,
absorbers, reheaters, dampers, pumps,
piping, and valves. The root cause of most
of these failures was corrosion or
degradation of the materials of construc-
tion. Over the last few years, EPRI has
initiated many projects aimed at under-
standing and eliminating corrosion
induced failures in scrubbers. Primary
emphasis has been on metallic materials,
but an increasing amount of effort is
being directed toward coatings, nonme-
tallic materials of construction, and
corrosion control techniques. The range
of EPRI's research on corrosion and
degradation of materials for FGD systems
is described in this paper.
Simultaneous Design,
Planning, and Materials of
Construction Selection for
FGD Systems
Alex Kirschner, Norman Ostroff*
Peabody Process Systems, Inc.
Stamford, CT
R.F. Miller, W.L Silence
Cabot Corporation
Kokomo, IN
Processes and systems designed for
emissions control from fossil fuel fired
boilers for electric generating stations are
many and varied, as are the choices of
materials of construction. Good perform-
ance, efficiency of operation, and main-
tenance of FGD systems can be enhanced
by the simultaneous selection of the
process, design, and materials of con-
struction of the system. The wet lime and
limestone systems are the dominant
processes for removing SOa from coal-
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fired boiler flue gases and will remain so
for the next several years, based on EPA
surveys. The choices of material include
carbon steel, coatings and linings that
can be applied over carbon steel, a wide
range of alloys that can be used in place of
lined carbon steel, and various nonmetal-
lic materials. This paper discusses the
corrosion and abrasion resistance of
these materials and shows how each may
be most advantageously used in the
design of an FGD system.
Acid Deposition in FGD
Ductwork
Daniel A. Froelich,* Carl V.
Weilert, Paul N. Dyer
Burns & McDonnell Engineering
Co., Inc.
Kansas City, MO
In the mid 1970's first generation wet
lime/limestone FGD systems were
included in the design of many new coal-
fired power plants across the U.S. in
response to federal, state, and local S02
emission control regulations. At the time,
the primary concern in the electric power
industry was whether the new systems
would work at all. In retrospect, the
overall performance of these FGD sys-
tems has been good. Based on data from
the best of these first generation systems.
Congress and EPA have effectively man-
dated the use of FGD systems on all
future coal-fired power plants. Continu-
ous SOz reduction is the law of the land.
Reliability is the new watchword for the
utility industry.
For owners and operators of existing
FGD systems and for designers and
suppliers of new systems, problems with
ductwork corrosion represent a major
obstacle to the goal of 100% reliability.
Corrosive failure of materials of construc-
tion in FGD system ductwork is a leading
contributor to low reliability in existing
FGD systems.
The corrosion experiences at the R.D.
Morrow Station are the prime example of
this industry-wide problem. The corrosion
rates of the alloys and coating materials
used at R.D. Morrow have been much
higher than anticipated in the design.
Some alloy materials chosen for repair of
the initial corrosion (on the basis of the
results of laboratory corrosion tests in
simulated FGD environments) have also
experienced rapid corrosion. In most
cases, even coupon spool tests conducted
at R.D. Morrow have been unable to
predict the severe corrosion that has
occurred when the test material was
installed full-scale in the ductwork.
Based on this experience it was
concluded that: (1) the corrosive environ-
ment in the ductwork is more aggressive
than that to which the spool coupons are
exposed; and (2) the corrosive environ-
ment in the ductwork is more aggressive
than that which had previously been
simulated in the laboratory. It was clear
that more and better data were needed to
define the conditions that existed in the
ductwork.
There was not sufficient information
available regarding the chemical compo-
sition of the material that collects on the
FGD ductwork surface. Collection, pre-
servation, and analysis of duct surface
deposits obtained during periodic inspec-
tions at the time of system outages had
proven to be difficult. Data from this type
of sample were inconsistent and mislead-
ing. It became clear that there was a
critical need for a method by which
ductwork deposition samples could be
obtained while the FGD system was
operating.
Burns & McDonnell has identified and
developed two innovative methods for
characterizing the corrosive environment
in FGD system ductwork. A predictive
technique based on vapor/liquid equili-
brium data for acid solutions is used to
estimate acid concentrations in ductwork
condensate. An extractive test method
utilizing a controlled-temperature con-
denser is used for on-line collection of
duct deposits from FGD system ductwork.
Working under contract with EPRI (Re-
search Project 1871-4), Burns & McDonnell
conducted a test program at R.D. Morrow
to evaluate the two methods. This paper
describes the two methods and their
applicability to the solution of corrosion
problems in FGD system ductwork.
In Situ Evaluation of High
Performance Alloys in Power
Plant Flue Gas Desulfurization
Scrubbers
R.W. Schutz
TIMET Division
Titanium Metals Corp. of America
Henderson, NV
Charles S. Young
Astro Metallurgical Division
Harsco Corp.
Wooster, OH
Preliminary data from ongoing in situ
FGD scrubber exposure tests, involving
specific high performance stainless
steels, and nickel-base and titanium
alloys are presented and discussed. Spool
rack exposures of 4-9 months involving
candidate alloys—Titanium Grades 2 and
12, 904L stainless steel, and nickel-base
alloys 625 and C-276—were conducted
in the inlet quench and outlet duct zones
of several operating power plant FGD
scrubber systems. In general, the per-
formance of titanium alloys was equal or
superior to that of the steel and nickel
alloys, particularly in outlet ducts. The
904L alloy consistently exhibited pooi
resistance to localized attack, while 62E
and C-276 alloy performance was varied
These findings are discussed relative t(
specific environmental considerations
and parallel laboratory and field studiei
reported in the literature.
Session 4. Dry Furnace
Absorbent Injection
Randall E. Rush, Chairman
Southern Company Services,
Inc.
Birmingham, AL
Results from EPA's
Development of Limestone
Injection into a Low NOX
Furnace
Dennis C. Drehmel, G. Blair
Martin, James H. Abbott
Industrial Environmental
Research Laboratory
U.S. Environmental
Protection Agency
Research Triangle Park,
NC 27711
This paper updates the status of EP/>
Limestone Injection into a Multista
Burner (LIMB) development, from tl
time of the paper presented at i
previous FGD meeting (May 1982)
Florida. The LIMB program is an El
effort to develop effective and inexpe
sive emission control technology for co
fired boilers that will reduce SO* and N<
LIMB technology represents a lo
cost alternative to currently available S
control approaches; e.g., FGD, c<
cleaning, and coal switching. LIT
technology is attractive if coal combust
must be controlled to minimize emissk
of acid rain precursors because LIME
easily retrofitted to large and small cc
fired boilers, is lower in cost than i
available alternative, and can con
both SO* and NO*—the two major <
rain precursors. The technical goals
the program are: (1) for retrofits, achi
50-60% reduction of both SO* and I
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from uncontrolled levels, (2) for new
systems, achieve 70-80% NOX and 70-
90% SOx reduction from uncontrolled
levels; and (3) for both retrofits and new
systems, achieve the above goals at costs
at least $100/kW less than the major
technology alternative, FGD.
Review of EPRI Research on
Furnace Sorbent Injection SOz
Control
Michael W. McElroy
Electric Power Research Institute
Palo Alto, CA
Direct furnace injection of alkaline
material is currently under development
as a potential low cost SC>2 control
approach for new and existing coal-fired
boilers. Major developmental efforts
now focus on (1) understanding process
fundamentals, (2) process optimization
for both new and retrofit applications, and
(3) the resolution of power plant impact
issues and costs. Current and planned
EPRI research projects in these areas are
reviewed.
Direct Desulfurization Through
Additive Injection in the
Vicinity of the Flame
M. Yaqub Chughtai,* Sigfrid
Michelf elder
L & C Steinmuller GmbH
West Germany
After a short description of the staged
mixing burner, the report deals with the
process of direct desulfurization in the
furnace of a steam generator by injection
of additives around the flame. Further,
the results from tests with a pilot burner
and intermediate results from tests in a
full-size boiler are given. Finally, the
possible applications and economic
aspects of direct desulfurization are
discussed.
Session 5. Dual Alkali
Norman Kaplan, Chairman
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Utility Double Alkali Operating
Experience
Dennis L Clancy
Southern Indiana Gas & Electric
Co.
Evansville, IN
Richard J. Grant
Central Illinois Public Service
Co.
Springfield, IL
L. Karl Legatski*
FMC Corporation
Schaumburg, IL
James H. Wilhelm
Codan Associates
Sandy, UT
Beth A. Wrobel
Northern Indiana Public Service
Co.
Wheatfield, IN
On April 6, 1983, Northern Indiana
Public Service Company started up its
Schahfer Unit 17, the first high-sulfur
coal boiler required to be in compliance
with the 90% S02 removal provision of
the 1979 revisions to the New Source
Performance Standards. This is the
fourth utility double alkali FGD system to
come on line in the last 4 years. All have
consistently met their S02 performance
criteria. This paper summarizes cost and
availability data for three of these
systems. While capital costs vary with
site-specific design criteria, operating
costs exclusive of capital charges are
typically 4 mills/kWh. Availabilities for
the double alkali systems as a group are
consistently higher than for direct
limestone. Unique features of the NIPSCO
design and operation are discussed, as
well as some important recent improve-
ments implemented at the Southern
Indiana Gas and Electric Co. and Central
Illinois Public Service Co. installations.
Pilot Evaluation of Limestone
Regenerated Dual Alkali
Process
John C.S. Chang*
Acurex Corporation
Research Triangle Park, NC
Norman Kaplan
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
This paper reports on the results of
tests (between February 1982 and March
1983) on a pilot-scale limestone dual
alkali FGD system established by EPA/
IERL-RTP. This recent pilot plant testing
showed that significant improvement in
soda ash consumption and filter cake
quality can be achieved with proper
system control. The causes of system
upset by nonsettleable solids were also
identified and demonstrated in tests. The
objectives of this paper were to give high-
lights of recent pilot plant testing and to
discuss, generally, limestone dual alkali
processes.
Session 6. Flue Gas Treatment
(Combined SOX/NOX)
J. David Mobley, Chairman
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Status of the DOE Flue Gas
Cleanup Program
John E. Williams
U.S. Department of Energy
Pittsburgh, PA
The U.S. Department of Energy directs
a substantial R&D effort to develop
advanced environmental control technol-
ogy for coal-fired stationary sources. The
Flue Gas Cleanup Program is aimed
primarily at post-combustion cleanup of
S02 and NO*; a small part of the program
is directed at characterization and
improved control of respirable particu-
lates. The programmatic goal established
at Fossil Energy Headquarters is the
development of technology options for
90% removal of both SOa and NOX, while
controlling particulates to the New
Source Performance Standards (NSPS).
Emphasis is placed on developing pro-
cess concepts that offer potential cost
reductions of 20% to 25%, compared to
commercially available technology (Se-
lective Catalytic Reduction of NOX followed
by a wet limestone scrubber and the
necessary baghouse or ESP). The com-
mercialization or application period is
expected to be in the late 1980s or early
1990s.
The Flue Gas Cleanup Program is
implemented by the Pittsburgh Energy
Technology Center (PETC). PETC is also
responsible for implementation of other
related research programs, including coal
preparation and direct coal combustion.
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and has been involved in flue gas cleanup
since the late 1950s.
The current DOE program is being
conducted by a cross-section of industrial
organizations, not-for-profit research
laboratories of universities, national
laboratories, and in-house research.
Many of the projects are new, and the
research is just beginning. A chronology
and overview of the program, together
with brief descriptions of the status of
individual projects, are given.
Status of SO2 and /VOX
Removal in Japan
Jumpei Ando
Chuo University
Tokyo, Japan
FGD capacity in Japan has increased
rapidly from 1970, reaching 108NmVh
(33,000 MW equivalent) in 1976, and
increasing slowly since. For NOXremoval,
selective catalytic reduction (SCR) of NOX
has been used in addition to combustion
modification. The SCR capacity increased
from 106 NmVh in 1976 to 7 x 107
NmVh in 1982. A combined flue gas
cleaning system (including SCR, ESP, and
FGD) has been applied to industrial
boilers and furnaces since 1975, and to
coal-fired boilers since 1980 to remove
50-90% of NOx and 90-95% of SO2. The
combined cleaning for coal costs 2-3
yen/kWh (244 yen = $1 as of 8/5/83),
including 7 years depreciation. Many
new coal-fired boilers with the combined
cleaning system have been planned
because of their economic advantage
over the use of low- or high-sulfur oil with
FGD, although the recent decrease in oil
price has reduced considerably the
economic advantage. Simultaneous SO2
and NO« removal processes were studied
eagerly between 1973 and 1978 and
applied to several small industrial boilers
and furnaces, but have not been used at a
large scale because of the problems
involved.
Panel: The Architect-Engineer-
Middleman Between Utility
and FGD Supplier
Archie V. Slack, Chairman
SAS Corporation
Sheffield, AL
Panel Members: Edward W.
Stenby, Gene H. Dyer, Paul R.
Predick, Michael L. Meadows,
Douglas B. Hammontree,
Christopher P. Wedig, Richard
Rao
Panel Discussion. The A-E -
Middleman Between Utility and
FGD Supplier
Edward W. Stenby*
Stearns-Roger Engineering
Corporation
Denver, CO
The A-E is hired to represent the owner
through all phases of a scrubber system
selection and installation. In this capacity,
the A-E is expected to exercise good
judgement in the areas of design and cost.
The owner, depending on the size of his
staff and his experience, may leave all or
most decisions to his A-E or he may
participate fully. We feel it is very
important that the owner participate fully
in all aspects of the scrubber system
design and installation, since he will be
left to operate the system after the vendor
and A-E have left.
The A-E's objective is to specify and
procure the most reliable scrubber
system at a low evaluated cost. The
scrubber business, however, is highly
competitive and the vendor's objective is
to win the award, knowing that low cost is
one of the primary selection parameters.
The document used by all parties to arrive
at the appropriate selection is the specifi-
cation. In Steams-Roger's opinion, a
good spec will detail not only basic design
criteria, but also minimum levels of
quality in equipment components, mater-
ials of construction, and equipment-
sparing philosophy. A very important area
is performance guarantees. A conserva-
tive spec may tend to drive the capital cost
of the scrubber system upward, but we
consider it to be the best means currently
of achieving high operating reliability.
However, a very detailed spec can conflict
with the owner's desire to obtain maxi-
mum vendor exposure on equipment
guarantees and performance guarantees.
By dictating too much of the system detail
design, the A-E and owner take some of
the risk.
The current fixed-price nature of the
FGD business forces the vendor to absorb
the risk of cost overruns. During the
proposal stage the vendor usually does
minimal engineering to prepare his bid.
Under these circumstances there will be
a tendency for the successful vendor to
protect his profit by calling for an extra,
every time the A-E or owner makes a
comment. The vendor will try to minimize
or prevent the owner and A-E from
interfering with the design and construc-
tion if they conform with the spec and the
intent of the spec. Again, the spec
becomes the all important document in
interpreting what is required and what is
acceptable. It is absolutely essential,
therefore, that a good spec be developed.
In order to ensure that a good proposal
is prepared, it is suggested that the owner
consider paying for the proposal. In this
manner, vendors will be encouraged to
do more engineering and provide better
detail of his proposed design. A limited
bidder's list goes hand in hand with this
approach.
One last thought...it must be remem-
bered that there are many "gray" areas in
scrubber design, and it is difficult, if not
impossible, to get all the details spelled
out clearly during the bidding phase. A
goal of the A-E is to interpret and help
coordinate the owner's requirements into
positive action by the vendor during the
design and construction phase. The
owner also has a responsibility to know
what he is buying and to apply standards
of operation and maintenance for the
scrubber system that are consistent with
the rest of the plant.
The Role of Engineer-
Constructors in Flue Gas
Desulfurization
Gene H. Dyer
Bechtel Group, Inc.
San Francisco, CA
First, I would like to note that I have
recast the title, since we think ol
ourselves as being Engineer-Constructors
rather than Architect-Engineers. We
believe that to be a distinct difference, ir
that it provides an ability to provide £
continuity between engineering anc
construction activities that is vital to th«
timely and successful completion of job:
involving complex systems.
Second, in the short time available,
would like to concentrate on the Engi
neering end of this subject.
Lastly, as a representative of th<
Research and Engineering part of thi
Bechtel Group of Companies, I would lik
to explain our views of development?
aspects of FGD, as well as its productio
engineering aspects.
Session 7. FGD Chemistry
Dorothy A. Stewart,
Chairwoman
Coal Combustion Systems
Division
-------
Electric Power Research
Institute
Palo Alto, CA
Influence of Chlorides on the
Performance of Flue Gas
Desulfurization
William Downs*
Babcock & Wilcox
Alliance, OH
Robert W. Aldred, L. Victoria
Tonty, Russell F. Robards,*
Richard A. Runyan
Tennessee Valley Authority
Chattanooga, TN
Dennis W. Johnson
Babcock & Wilcox
Barberton, OH
A pilot plant test program was performed
to determine what effect high concentra-
tions of chloride might have on the
performance of limestone-based FGD
processes. This test program took place
during January and February 1983 at
TVA's Shawnee Steam Plant. The specter
of high chloride concentration arises
from a trend toward closed-loop opera-
tion. The influence of chlorides on S02
absorption was examined. 161 limestone
tests were completed. The principal
conclusion that can be drawn from this
test program is that chlorides generally
inhibit S02 absorption. The severity of
this effect can vary widely, however,
depending on the design and method of
operation.
Effect of High Dissolved Solids
on Bench-Scale FGD
Performance
James B. Jarvis,* Timothy W.
Trofe
Radian Corporation
Austin, TX
Dorothy Stewart
Electric Power Research
Institute
Palo Alto, CA
To minimize wastewater treatment
costs, utilities are evaluating the use of
cooling tower blowdown as makeup
water for wet limestone FGD systems. If
closed-loop operation is employed, the
dissolved species in the makeup water
can be concentrated to significant levels.
Additional ions may enter the scrubbing
liquor through the absorption of chemical
species in the flue gas. An important
example is the absorption of HCI pro-
duced during the combustion of high
chloride coal.
The effect of various high total dis-
solved solids (TDS) solutions on S02
removal and other system variables was
evaluated in a bench-scale limestone
FGD system. Five salts (CaCI2, MgCI2,
NaCI, MgSO* and NazSCU) were evalu-
ated under both natural and forced-oxida-
tion conditions. Additional laboratory
testing was conducted to isolate specific
effects observed in the more complex
bench-scale tests. These tests were de-
signed to illustrate the effect of high TDS
solutions on chemical equilibria and
gas/liquid mass transfer in the absorber.
The results of this investigation show
that the performance of the FGD system
is determined by the effect of the added
salt on: (1) the concentration of dissolved
ions in the scrubbing slurry, (2) the solu-
bility of dissolved SOa, (3) mass transfer
enhancement through the formation of
bi-sulfite ion pairs with the added cation,
(4) sulfate/bisulfate buffering in high
sulfate systems, and (5)the mass transfer
rate of diffusing species through the
liquid film at the gas/liquid interface. The
bench-scale test results also compare
favorably to the results from similar tests
conducted at TVA's Shawnee Test
Facility in Paducah, KY, and EPA's pilot
facility at Research Triangle Park, NC.
Pilot Plant Tests on the Effects
of Dissolved Salts on Lime/
Limestone FGD Chemistry
Dennis Laslo*
Peabody Process Systems, Inc.
Stamford, CT
John C.S. Chang
Acurex Corporation
Research Triangle Park, NC
J. David Mobley
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
This paper is an overview of pilot plant
testing from September 1981 through
June 1983 of the effects of dissolved salts
on a lime or limestone FGD system at
EPA's Industrial Environmental Research
Laboratory, Research Triangle Park, NC.
Tests were conducted using a three-
stage turbulent contact absorber (TCA)
with a typical gas flow rate (G) of 465
mVhr (0.1 MW) and absorbing slurry
chloride ion (Cl~) concentrations ranging
from 160 to 180,000 ppm.
The FGD processes investigated include
conventional lime/limestone, magnesia
enhanced limestone, and limestone with
two-tank forced oxidation. Data indicate
that the effects of Cf on the performance
of the absorber are a function of the
cations associated with Cl~ and scrubber
operating conditions. The accumulation of
calcium chloride decreased system pH
and S02 removal efficiency, occasionally
decreased slurry settling rate, and
increased gypsum scaling potential.
When magnesium was the cation, the
increase of Cl~ concentration improved SOs
removal efficiency at Cl~ concentrations
below 40,000 ppm. No significant effects
were observed using sodium chloride at
Cl~ concentrations less than 50,000 ppm.
However, when Cl~ concentrations were
greater than 70,000 ppm, S02 removal
efficiency and system pH declined with
the accumulation of either magnesium or
sodium chloride. Significant decreases in
SOz removal efficiency were also observed
when lime was used in the natural
oxidation mode with high inlet SO2
concentrations. Calcium chloride had
minor effects on the performance of a
DBA enhanced limestone scrubber. Most
gypsum specifications required for
wallboard manufacturing were met by
washing cake using a pilot belt filter.
Modeling of SO2 Removal by
Limestone Slurry Scrubbing:
Effects of Chlorides
Pui K. Chan, Gary T. Rochelle*
University of Texas at Austin
Austin, TX
A model of limestone slurry scrubbing
with staged contacting has been devel-
oped by integrating gas/liquid mass
transfer of SOa, C02, and 02 and
dissolution of limestone and calcium
sulfite solids. The model was used to
predict SO2 removal as a function of NaCI
and CaCI2 accumulation in the solution.
Experimental data from three different
pilot plants were accurately simulated.
Chloride accumulation reduces SOz re-
moval by its effects on the S02 hydrolysis
equilibrium. Calcium accumulation re-
duces S02 removal by its effect on SOa=
and HC03" in the scrubber solution. Sulfite
oxidation in the scrubber can obscure the
effects of CaCI2 accumulation. The model
predicts the effect of dibasic (glutaric)
acid on S02 removal with solutions con-
taining 0.7 M CaCI2.
-------
Influence of High Dissolved
Solids on Precipitation Kinetics
and Solid Particle Size
Frank B. Meserole, Timothy W.
Trofe
Radian Corporation
Austin, TX
Dorothy A. Stewart*
Electric Power Research
Institute
Palo Alto, CA
This paper presents results of a study to
screen the effects of high concentrations
of dissolved ions on the precipitation of
calcium sulfate dihydrate, gypsum, and
the solid solution of sulfate with calcium
sulfite hemihydrate. A series of precipita-
tion measurements were conducted in
the presence of combinations of magne-
sium, sodium, calcium, chloride, and
sulfate at total dissolved solids levels up
to 240,000 mg/L.
Significant differences in the precipita-
tion rates and habit and size of the
precipitated solids were observed for
several of the test solutions as compared
to precipitation from dilute solutions.
Gypsum precipitation rate in high IDS
solutions was accelerated in high TDS
solutions, especially those containing
chloride ion. The calcium sulfite/sulfate
hemihydrate solid solution precipitation
rate was faster in sulfate ion solutions.
These results suggest that the opera-
tion of FGD systems at high dissolved
solids concentrations can alter the
precipitation kinetics. Attempts to model
these effects will require the incorpora-
tion of the concentrations of specific ions
in the kinetic relationships.
Effect of Limestone Grinding
Circuit on FGD Performance
and Economics
J. David Colley,* O.W. Hargrove
Radian Corporation
Austin, TX
Dorothy A. Stewart
Electric Power Research
Institute
Palo Alto, CA
Results of several recent EPRI spon-
sored programs investigating technical
and economic issues of limestone prep-
aration for SOa scrubbing are presented
in this paper. Variables important in the
selection of a limestone for FGD applica-
tion are discussed. The most common
method used by vendors for sizing
limestone ball mills is identified. Correla-
tion of this method with the chemical,
physical, and petrographic characteristics
of several different limestones was inves-
tigated.
Pilot-scale testing with a wet ball mill,
air-swept ball mill, tower mill, ring roller
mill, and hammer mill was conducted
with three of these limestones. Selection
of the stones was based on the strength
of the material. Hard, medium, and soft
stones were used so that the effect of this
variable on each machine's performance
could be measured. Data were collected
on the performance of these machines in
grinding these limestones to various
particle size distributions. Product samples
collected from each were tested in
laboratory equipment to measure the
effect of grinding method on limestone
dissolution rate.
Full-scale testing at Central Illinois
Light Co.'s Duck Creek Unit 1 measured
the effect of the limestone mill circuit
operation on the product particle size
distribution. Testing also quantified the
effect of the limestone size distribution on
its utilization in the scrubbers. The
economic tradeoffs of producing the finer
size product were estimated based on
data collected during the on-site testing.
Session 8. Limestone/Organic
Acid
J. David Mobley, Chairman
Industrial Environmental
Research Laboratory, U.S.
Environmental Protection
Agency, Research Triangle Park,
NC
Process Troubleshooting at a
Utility Limestone FGD System
J. David Colley, Robert L Glover
Radian Corporation, Austin, TX
Temple Donaldson, Central
Illinois Light Company, Peoria, IL
Dorothy Stewart, Electric Power
Research Institute, Palo Alto, CA
Central Illinois Light Co.'s Duck Creek
Unit 1 experienced significant reliability
and operating problems with its limestone
FGD system following start-up in 1979.
CILCo entered into a testing and evalua-
tion program co-funded by the Electric
Power Research Institute in late 1981 to
verify the feasibility of using additives to
improve the system's low SOz removal
efficiency. A second objective of the work
was to improve the system's reliability,
which averaged slightly better than 60%
prior to testing. Severe mist eliminator
scaling that was causing routine outages
was primarily responsible for the re-
liability problems. The 8-month program
that followed involved extensive chem-
ical process troubleshooting.
Two types of organic acid buffers were
tested along with the addition of mag-
nesium oxide during the period. Both di-
basic acid and the magnesium proved
capable of enhancing SOa removal to
levels sufficient to maintain the unit in
compliance with the 1971 SO2 NSPS. An
economic analysis was performed based
on the data collected during this testing.
The cost study compared capital and
annual operating and maintenance costs
for each option over the remaining life of
the plant.
Work was conducted with the additive
testing to solve the mist eliminator
scaling. The cause of the scaling was
identified and effectively stopped by
switching to a fresh water wash, adjusting
the wash sequence, and improving lime-
stone utilization. Limestone utilization
was improved by optimizing the operation
of the mill circuit to provide a finer, more
reactive product. Since completion of the
program, the FGD system has consistent-
ly achieved reliability greater than 95%
while, at the same time, lowering opera-
ting and maintenance costs.
Technical/Economic Feasibility
Studies for Full Scale
Application of Organic Acid
Technology for Limestone FGD
Systems
James C. Dickerman*
Radian Corporation
Research Triangle Park, NC
J. David Mobley
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
The application of organic acid buffe
enhancement to FGD systems is a recer
development that has resulted in lowere
costs and improved performance fc
systems that have adopted its use.
process which uses organic acids as a
additive has several advantages ov<
conventional limestone scrubbing sy
terns, including system flexibility (e.j
ability to respond to unplanned fluctu
-------
tions in coal sulfur content), and improved
process reliability. This paper summarizes
the results of several cost analyses which
were performed to evaluate the potential
economic benefits of converting opera-
ting FGD systems to organic-acid-en-
hanced limestone scrubbing systems.
Also, since the last FGD symposium, two
full-scale utility limestone scrubbing sys-
tems have converted to organic-acid-en-
hanced operations. A summary of the
first year of operation for one of those sys-
tems—City Utilities' Southwest Power
Plant—is also included.
Session 9. Waste
Disposal/Utilization
James D. Kilgroe, Chairman
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Full-Scale Field Evaluation of
Waste Disposal from Coal-
Fired Electric Generating
Plants
Julian W. Jones*
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
John T. Humphrey
Haley & Aldrich, Inc.
Cambridge, MA
Chakra J. Santhanam, Armand
Balasco, Itamar Bodek, Charles
B. Cooper
Arthur D. Little, Inc.
Cambridge, MA
Barry K. Thacker
Geologic Associates, Inc.
Knoxville, TN
This paper summarizes results of a 3-
year study of current coal ash and FGD
waste disposal practices at coal-fired
electric generating plants. The study,
conducted by Arthur D. Little, Inc., under
EPA contract 68-02-3167, involved
characterization of wastes, environment-
al data gathering, evaluation of environ-
mental effects, and engineering/cost
evaluations of disposal practices at six
sites in various locations around the
country. Results of the study are expected
to provide technical background data and
information to EPA, state, and local
permitting officials, and the utility
industry for implementing environment-
ally sound disposal practices.
Data from the study suggest that no
major environmental effects have occurred
at any of the six sites; i.e., data from wells
downgradient of the disposal sites indi-
cate that waste leachate has resulted in
concentrations of chemicals less than the
EPA primary drinking water standards. A
generic environmental evaluation based
on a matrix of four waste types, three
disposal methods, and five environmental
settings (based on climate and hydrogeo-
logy) shows that, on balance, technology
exists for environmentally sound disposal
of coal ash and FGD wastes for ponding,
interim ponding/landfilling, and landfill-
ing. For some combinations of waste
type, disposal method, and environmental
setting, mitigation measures must be taken
to avoid adverse environmental effects.
However, site-specific application of good
engineering design and practices can
mitigate most potentially adverse effects
of coal ash and FGD waste disposal. Costs
of waste disposal operations are highly
system and site specific.
Operations History of Louisville
Gas & Electric FGD Sludge
Stabilization
Robert Van Ness*
Louisville Gas & Electric
Company
Louisville, KY
John H. Juzwiak, P.E.
Conversion Systems, Inc.
Horsham, PA
William Mclntyre
Conversion Systems, Inc.
Louisville, KY
The Louisville Gas & Electric Company
(LG&E) has been an industry leader in
the deployment of FGD technology from
its very inception. LG&E was one of the
first major utilities to install SC-2 scrub-
bers; it now operates seven scrubbers
serving a combined generating capacity
exceeding 2200 MW. These scrubbers,
purchased from several manufacturers,
represent a broad spectrum of scrubber
technologies including dual alkali, lime,
and limestone systems.
The bleed stream from these scrubbers
is dewatered, and the resulting solids are
chemically and physically stabilized in
processing plants purchased from Con-
version Systems, Inc. (CSI), a pioneer in
the field. Unit 6 at Cane Run, a 270-MW
unit with a dual alkali scrubber, is served
by a stabilization facility which began
operations in April 1980. Units 4 and 5 at
Cane Run have a combined capacity of
360 MW and are equipped with lime
scrubbers. The waste from these scrub-
bers is combined and treated in another
stabilization facility. The four units at Mill
Creek have a combined capacity exceed-
ing 1600 MW and are also equipped with
lime scrubbers. One large stabilization
facility was installed to handle the
combined bleed from the four Mill Creek
scrubbers.
The stabilization plants have run for
about 3 years and are operated and
maintained by LG&E personnel with ad-
visory assistance supplied by CSI. The
knowledge gained from the experiences
of LG&E and CSI in the last 3 years of
operation would be useful both to current
operators of stabilization facilities and to
those who are anticipating the procure-
ment of scrubbers and stabilization
facilities.
This paper presents some of the
operating and maintenance history
which has been obtained from these
plants. Included are discussions on
reliability of individual equipment and
discussions of some modifications which
were made to improve reliability. Operat-
ing problems are addressed, including
some of the inherent difficulties encoun-
tered in processing scrubber sludge and
fly ash.
In addition, the landfill operation which
is an integral part of the stabilization
process is discussed, as well as the
results of several years of landfill investi-
gation. Also discussed is the impact of the
landfill operation and plant control on the
environmental properties of the final
landfilled material.
Coal Waste Utilization in
Artificial Reef Construction
Jeffrey H. Parker,* P.M.J.
Wood head
State University of New York
Stony Brook, NY
Dean M. Golden
Electric Power Research
Institute
Palo Alto, CA
The technology of coal combustion has
improved greatly over the last few
decades. One result of the elaborate
-------
emission control equipment required on
coal plants to meet stringent air quality
requirements is the large amount of
waste that must be utilized or disposed of
safely. FGD sludge and fly ash may be
produced at the rate of as high as 1,000
tons/day at a typical coal-fired power
plant. Waste disposal, especially in urban
coastal areas, has become a major
obstacle to conversion to coal combustion
for generating electricity.
To assess a possible solution to the
waste disposal problem, 500 tons of FGD
sludge and fly ash were stabilized into
blocks and placed in the ocean as an
artificial reef. Previous laboratory investi-
gations had indicated that no toxic
chemical or physical effects should occur
in the marine environment. After 3 years
in the sea, the coal waste blocks support a
diverse community of reef fish and
invertebrates and have maintained their
structural integrity. No adverse environ-
mental effects have been detected.
Assuming that the coal waste blocks
continue to be environmentally acceptable
in the marine environment, the engineer-
ing and economic feasibility of this
method of disposal should be confirmed.
Solid Waste Environmental
Studies at Electric Power
Research Institute
Ishwar P. Murarka
Electric Power Research
Institute
Palo Alto, CA
Solid Waste Environmental Studies
(SWES) at Electric Power Research
Institute (EPRI) is a comprehensive
research project aimed at generating
predictive methods and the essential data
bases to evaluate the effect of disposal
and reuse of solid waste produced from
fossil fuel combustion and flue gas
cleanup operations on groundwater
quality. EPRI has developed detailed
research plans and has initiated research
in leaching chemistry, chemical attenua-
tion mechanisms, groundwater transport
processes, and the evaluation of existing
geohydrochemical models. For the next 3
or 4 years, fundamental research in
geochemistry and geohydrology is ex-
pected to yield quantitative data on
release rates, transformation character-
istics, and subsurface transport of
inorganic solutes leached from waste.
Results of the research will be integrated
by improving or developing new predictive
methods and by validating the results with
data from operating facilities.
Session 10, Part I. Dry FGD:
Pilot Plant Test Results
Theodore G. Brna, Chairman
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Current Status of Dry SO2
Control Systems
Michael A. Palazzolo*
Radian Corporation
Research Triangle Park, NC
Theodore G. Brna
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Mary E. Kelly
Radian Corporation
Austin, TX
This paper updates commercial appli-
cations and research and development
(R&D) activities involving three dry SOz
control technologies: spray drying, dry
injection, and electron-beam irradiation.
Spray drying continues to be the only
commercially applied dry FGD process, with
two additional spray drying systems sold
since mid-1982. To date, 17 commercial
utility spray drying systems have been
sold, totaling over 6800 MWe. Six of
these systems are currently operational;
two of them have been turned over to the
utility. In addition to the utility applications,
there are 21 industrial spray drying units,
7 of which are expected to start up in the
next 2 years. Demonstration- and pilot-
scale testing of the spray dryer process is
continuing with emphasis on high sulfur
applications.
The first planned commercial applica-
tion of dry injection technology has been
announced for a 500 MWe utility. The
recent demonstration-scale testing on a
22 MWe unit has been completed.
The electron-beam process is also in an
early developmental state. Pilot-scale
testing of the electron-beam/lime spray
drying version of the process is scheduled
to begin this fall.
Acid Rain Prevention Through
New SOx//VOx Dry Scrubbing
Process
Karsten Felsvang, Per Morsing
A/S Niro Atomizer, Soeborg
Denmark
Preston Veltman
Niro Atomizer, Inc.
Columbia, MD
Acid rain has attracted much attention
both in the U.S. and in Europe. To cope
with problems associated with acid rain,
Niro Atomizer is developing a dry scrub-
bing process for simultaneous removal of
SOx and NOX.
A description of the process is given in
this paper. The equipment used is essen-
tially the same as used in the over 5000
MW utility dry scrubbers currently in
operation, start-up, or under construc-
tion.
Pilot plant test results from the
Copenhagen dry FGD facility and results
achieved during a full-scale demonstra-
tion of the process at one of Joy/Niro's
operating dry scrubbers are presented.
Waste product characteristics are
shown and compared with EPA stand-
ards.
Finally, the process economics are
analyzed and compared with other
existing processes for SOX/NOX removal.
Process Characterization of
SOz Removal in Spray
Absorber/Baghouse Systems
Eric A. Samuel,* Thomas W.
Lugar, Dennis E. Lapp, Kenneth
R. Murphy
General Electric Environmental
Services, Inc.
Lebanon, PA
Ronald L. Ostop
Department of Public Utilities
City of Colorado Springs
Colorado Springs, CO
Theodore G. Brna
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
A new equation for correlating SO:
removal with stoichiometric ratio, approach
to saturation, inlet SOa concentration
inlet temperature, and inlet moisture
content is proposed. It reveals essentia
information about the kinetics of the SO;
removal process. The chemical reactior
between the SOz and lime appears U
limit the rate of SOa removal in the spra^
W
-------
absorber. The effect of recycle enhance-
ment of S02 removal may be understood
in terms of this model. The model also
permits a classification of fly ash suitable
for designing dry flue gas desulfurization
(DFGD) systems.
DFGD pilot plant results are reviewed
from theoretical and mechanistic view-
points. SOz removal as a function of the
gas flow rate (or average residence time)
and the angle of the secondary swirl
vanes in the absorber gas disperser is
discussed relative to the velocity flow
field in the absorber. SOZ removal
efficiency is also discussed as a function
of the atomizer angular speed.
When the gas flow rate and approach to
saturation are fixed, SOz removal effi-
ciency in the spray absorber increases
with increasing stoichiometric ratio and
inlet temperature and decreasing inlet
moisture content and SOz concentration.
An explanation of these effects is given by
their impact on the droplet diameter
integrated over the lifetime of the
droplets. Another effect that increases
the time-integrated droplet diameter is
the decrease in the volume of the core of
solids (lime) for smaller slurry droplets.
Partial recycle of the spent products,
in the absence of externally injected fly
ash, results in SOz removal efficiency
being nearly independent of SOz concen-
tration. Thus, the enhancement from
recycle is greater for the higher SOz
concentrations. SOz removal performance
with recycle was improved by injecting fly
ash derived from a low sulfur Texas
lignite and from high sulfur eastern coals.
The enhancement with recycle in the
latter case is dramatic and supports
DFGD applicability to high sulfur coal.
Dry Scrubber, flue Gas
Desulfurization on High-Sulfur,
Coal-Fired Steam Generators:
Pilot-Scale Evaluation
Bryan J. Jankura,* John B.
Doyle, Thomas J. Flynn
Babcock & Wilcox Company
Alliance, OH
This paper describes the pilot-scale
investigation of methods for adapting dry
FGD to utility steam generators burning
high-sulfur coal. Development of the dry
scrubber for FGD was initially directed
toward reducing SOz in steam generators
burning low-sulfur western coals. The
reason for limiting dry scrubbing to low-
sulfur coals was two-fold: first, federal
New Source Performance Standards
(70% reduction) were less stringent; and
second, western coals generally contain
less sulfur and large amounts of ash
alkali, contributing significantly to the
effectiveness of the dry scrubbing
process. Several potential drawbacks
(both technical and economic) limiting dry
scrubber technology to western coals are
discussed.
The Department of Energy (DOE)
conducted dry scrubber FGD tests in
1981. Preliminary results indicated dry
scrubbing could remove more than 90%
of the sulfur released from the combus-
tion of eastern coals at less-than-
anticipated levels of lime consumption.
The Babcock & Wilcox Company, under
DOE contract, has tested the dry scrub-
bing process to evaluate the variables
that have a major effect on SOz capture.
There are ways of increasing SOz
capture by dry scrubbing. One method
requires limestone injection into the
boiler furnace (reducing SOz levels to the
scrubber), calcines limestone to more
reactive lime, and simulates a high-
alkali-ash, high-sulfur coal. Other meth-
ods include recycle and dry scrubber
approach to saturation at temperatures
less than 20°F to obtain high SOz capture.
EPRI Spray Dryer/Baghouse
Pilot Plant Status and Results
Gary M. Blythe*
Radian Corporation
Austin, TX
Richard G. Rhudy
Electric Power Research
Institute
Palo Alto, CA
In February 1982, the Electric Power
Research Institute (EPRI) initiated a 2.5
MW spray dryer/baghouse FGD pilot
plant program at their Arapahoe test
facility. The objective of the pilot plant
program is to confirm the capabilities of
the FGD process and to provide the
electric utility industry with reliable
design and operating information for
spray dryer/baghouse FGD systems. The
pilot unit was described, and initial
results for sodium carbonate and once-
through lime operation were presented at
the May 1982 FGD symposium in
Hollywood, FL. This paper presents the
results of test work conducted from May
1982 through August 1983.
Most of the test work has been
conducted with lime reagent in the
recycle, rather than one-through mode.
Effects of a number of variables have
been studied. Spray dryer inlet SOz
concentrations have been varied from a
nominal 350 ppm up to 2000 ppm. Other
variables examined have included re-
agent ratio, recycle rate, system flue gas
flow rate, atomizer feed slurry preparation
and feeding configurations, and approach
to adiabatic saturation at the dryer outlet.
A significant result has been the observa-
tion that recycle operation greatly improves
spray dryer operation in addition to
improving SOz removal performance.
The fabric filter has been shown to
contribute significantly to overall system
SOz removal, particularly at higher
system removal levels (80% and greater).
No bag/fabric-related problems have
been observed. However, corrosion of
mild steel baghouse walls and mild steel
caps on bags near the walls has in some
instances been severe. The corrosion has
been largely attributed to insufficient
insulation of baghouse surfaces, and to
the fact that the pilot-scale compartment
shares no common walls with other
compartments. As a result of several bag
cap failures, the fabric filter compartment
was re-bagged in April 1983. The new
bags were brought on-line with no condi-
tioning by fly-ash-only operation, and
(after 4 months) continue to operate at a
very low pressure drop.
Session 10, Part II: Dry FGD:
Full Scale Installations
Richard G. Rhudy, Chairman
Coal Combustion Systems
Division
Electric Power Research
Institute
Palo Alto, CA
Field Evaluation of a Utility
Dry Scrubbing System
Gary M. Blythe,* Jack M. Burke
Radian Corporation
Austin, TX
Theodore G. Brna
Industrial Environmental
Research Laboratory
U.S. Environmental Protection
Agency
Research Triangle Park, NC
Richard G. Rhudy
Electric Power Research
Institute
Palo Alto, CA
This program, cofunded by the U.S.
Environmental Protection Agency and
the Electric Power Research Institute,
11
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has resulted in an evaluation of a full-
scale utility spray-dryer/baghouse dry
FGD system. The system is installed at
the Northern States Power Company's
Riverside Station and treats flue gas from
a nominal 100 MW of coal-fired power
generation. This has been the first
independent evaluation of a full-scale
spray-dryer/baghouse system.
For the test program, two coals were
used as boiler fuels, a subbituminous coal
and coke mixture with a nominal 1.2%
sulfure content, and a 3.4% sulfur Illinois
bituminous coal.
During the test program, SOa removal,
particulate emissions, sulfuric acid
removal, and extensive process data
were recorded. The test program was
conducted from July to October 1983, so
only preliminary results are presented.
Low sulfur coal tests indicated up to
90% SOz removal was achievable in
the short term with slightly sub-stoichio-
metric amounts of lime addition. A similar
removal was achieved in short term tests
with high sulfur coal at reagent ratios of
1.3 to 1.4. Calcium chloride addition was
found to reduce the lime addition
requirements for high sulfur tests by
about 25%.
Overview and Evaluation of
Two Years of Operation of the
Riverside Spray Dryer System
John M. Gustke, Wayne E.
Morgan, M.D.*
Black & Veatch
Kansas City, MO
Steven H. Wolf
Northern States Power
Company
Minneapolis, MN
Initial operation of the 100 MW spray
dryer system at Northern States Power
Company's Riverside Generating Station
began in November 1980. At that time, a
comprehensive test program was initiated
to demonstrate the suitability of dry FGD
for utility coal fueled boilers. Since initial
operation of the Riverside spray dryer
began, other publications have described
individual aspects of this system's
performance. This paper provides a
comprehensive analysis and overview of
the performance test data collected
during the initial 2 years of operation of
the Riverside spray dryer.
Overall data correlations describing
important variables in spray dryer opera-
tion and performance are established
from test results obtained during opera-
tion of the Riverside spray dryer system
under a wide range of conditions.
Correlations between total and fabric
filter S02 removal and parameters such
as lime stoichiometric ratio, total alkalin-
ity, and approach temperature are
presented for several different coals.
Variations in moisture content of the
solids collected in the spray dryer and
fabric filter are evaluated to establish
their sensitivity to a wide range of
operating variables. In addition, system
operation and control experiences are
described to illustrate the interaction
between flue gas flow, feed slurry flow,
absorber outlet temperature, and SOa
emissions during normal operation, as
well as during transient conditions such
as start-up, shutdown, and load swings.
The effects of boiler soot blowing on the
flue gas saturation temperature and
system control are also discussed.
Design and Initial Operation of
the Spray Dry FGD System at
the Marquette Michigan
Board of Light and Power
Shiras #3 Plant
O. Fortune,* T.F. Bechtel
General Electric Company
Lebanon, PA
E. Puska
Board of Light & Power
Marquette, Ml
J. Arello
Lutz, Daily & Brain
Shawnee Mission, KS
This paper discusses the design issues,
design decisions, start-up, and early
operation of the Spray Dry Flue Gas
Desulfurization (SDFGD) system which
went into operation at the Marquette (Ml)
Board of Light and Power's Shiras Unit 3
in May 1983. This 44-MW unit (consist-
ing of a rotary atomizer reactor, reverse
air fabric filter, lime preparation, and
reagent recycle system) was engineered
in the 1980-82 period utilizing pilot plant
and prototype industrial system results as
a design basis.
The initial operation of the unit is
discussed, as is the success of the
scaleup from pilot plant to commercial
size boiler.
Start-up and Initial Operating
Experience of the Antelope
Valley Unit J Dry Scrubber
Robert L. Erikson,* Frederick R.
Stern
Basin Electric Power
Cooperative
Bismarck, ND
Richard P. Gleiser
Joy Manufacturing Company
Montgomeryville, PA
Stanley J. Shilinski
Niro Atomizer, Inc.
Columbia, MD
The first competitively bid and awarded
utility dry scrubbing system utilizing lime
as the scrubbing reagent was for Basin
Electric's Antelope Valley Station Unit 1.
Awarded in 1978 to Joy Manufacturing
with Niro Atomizer as the major subcon-
tractor, the system was scheduled to start
up in 1981; however, due to reduced load
growth, start-up was delayed until this
year.
The dry scrubbing system treats flue
gases from a 435-MW lignite-fired boiler
and consists of reagent preparation
equipment, five spray dryer absorbers,
and two fabric filters.
Initial operation on coal began in May
1983, and commercial operation of the
system is scheduled for July 1984. This
paper reviews the start-up procedure,
problems which have developed thus far
and how they have been handled, and
results of the operation of the system to
date.
Characterization of an
Industrial Spray Dryer at
Argonne National Laboratory
Paul S. Farber,* C. David
Livengood
Argonne National Laboratory
Argonne, IL
Argonne National Laboratory (ANL) i
operating an industrial-scale coal-fire
boiler with a flue gas cleaning (FGC
system consisting of a spray dryer an
fabric filter. This paper describes the FG1
system and gives the status of an EP^
sponsored project being carried out b
ANL to characterize the operation of th
system. This project involves a design ar
economic analysis of the FGC systen
determination of waste characteristic
and analysis of system operation throuc
monitoring of inlet/outlet gas strean
and sampling of various process stream
Preliminary data and material balanc*
are presented in the paper, as well as
proposed performance model based i
an analysis of key operating parametei
12
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Unpresented Papers
An Economic Evaluation of
Limestone Double Alkali Flue
Gas Desulfurization Systems
Gerald A. Hollinden
Tennessee Valley Authority
Chattanooga, TN
C. David Stephenson
Tennessee Valley Authority
Muscle Shoals, AL
John G. Stensland
FMC Corporation
Schaumburg, IL
Considerable work was done at the
EPA Scholz plant in defining the process
parameters for limestone double alkali
flue gas desulfurization systems. In
general this study proved the viability of
the process but uncovered several less
than optimum operating parameters that
needed further work. FMC and others
have continued to work with the process
and have defined operating parameter
changes necessary to make the system
commercially viable.
Limestone double alkali is especially
appropriate for FGD systems applied to
boilers burning relatively high sulfur (2%
and greater) fuel. A discussion of site-
specific design criteria which impact on
the selection of FGD technology is
included with a definition of the optimum
parameters for the applications of
limestone double alkali.
An in-depth economic analysis of the
system is included with comparisons to
conventional limestone scrubbing tech-
nology. Cost comparisons are made by
subsystems such as absorber system,
reagent handling, storage and preparation
system, and solids waste production and
disposal. The economic data presented
are primarily a result of work done by TVA
under contract from the EPA.
Developments and Experience
in FGD Mist Eliminator
Application
Richard T. Egan
The Munters Corporation
Ft. Myers, FL
William Ellison
Ellison Consultants
Monrovia, MD
This paper details available mist-elimi-
nator technology and assesses U.S.
practices and experience in utilizing
these sub-systems of FGD processes.
Pertinent trends in FGD system design
and operation tied to the criticality of mist
eliminator performance are identified
and discussed, and advancements in
eliminator selection and application are
reviewed. Case histories of several sig-
nificant existing mist eliminator facilities
are described, and the importance of
selection of internals design and arrange-
ment permitting use of elevated mist-
eliminator inlet-face gas velocity to
enhance droplet separation forces is
emphasized.
FGD Gypsum: Utilization vs.
Disposal
William Ellison
Ellison Consultants
Monrovia, MD
This paper gives a technical and
economic evaluation of alternative means
of managing wastes collected in forced-
oxidation (FO) FGD systems. Worldwide
application of FO-FGD is described, and
environmental considerations in selec-
tion of waste management alternatives -
gypsum utilization vs disposal - are
reviewed. Feasibility of and barriers to
commercial gypsum from FGD in North
America during the 1980s are analyzed.
The impetus, method of implementation,
and potential for gypsum use are addressed
for major by-product gypsum FGD instal-
lations now in operation, under construc-
tion, or being designed. It is concluded
that, in many instances, the production
and sale of usable gypsum from FGD
would be a benefit and a source of direct
profit to the utility plant owner, but that in
most cases the gypsum depletion allow-
ance under IRS Code 613B will continue
to be a major disincentive for purchase of
by-product gypsum by vertically integrated
gypsum companies in U.S.
Operating Experience with the
Chiyoda Thoroughbred 121
Flue Gas Desulfurization
System
Seiichi Kaneda, Mitsuhiro
Nishimura
Mitsubishi Petrochemical
Company
Yokkaichi, Japan
Hitoshi Wakui, Ikuro Kuwahara
Chiyoda Chemical Engineering
and Construction Company,
Ltd.
Yokohama, Japan
Donald D. Clasen
Chiyoda International
Corporation
Seattle, WA
This paper reviews the design and
operating experience of the Chiyoda
Thoroughbred 121 FGD system installed
and operated by Mitsubishi Petrochemi-
cal Company at their Yokkaichi, Japan,
complex.
The plant consists of a single scrubber
and treats 260,000 NmVh (162,000
scfm) of flue gas from a 280 T/h (87 MW
equivalent) boiler burning high sulfur oil.
Plant operation, since start-up in May
1982, has been smooth and trouble free
over a wide range of operating conditions.
Plant reliability has been 100%. The plant
is operated at a SO2 removal efficiency of
97-99% for inlet SOa concentrations ran-
ging between 1000 and 2000 ppm. Lime-
stone utilization is greater than 99%, and
the dry gypsum by-product is sold to a
wallboard manufacturer. Operating and
maintenance functions for the system are
minimal and completely absorbed by
normal boiler plant operations.
Operation Experience with
FGD Plant II at Wilhelmshaven
Power Plant, West Germany
B. Stellbrink
Power Plant Wilhelmshaven
West Germany
H. Weissert
Bischoff GmbH
Essen, West Germany
P. Kutemeyer
Bischoff Environmental Systems
Pittsburgh, PA
The Nordwestdeutsche Kraftwerke
Aktiengesellschaft (NWK) has been
operating a 720 MW coal-fired power
plant in Wilhelmshaven, West Germany,
since 1976. In March 1982, the second
FGD plant (called REA 2) was placed in
operation after a 2-year construction
period. Start-up and checkout proceeded
without major difficulties and was
completed within about 3 months.
Beginning in June 1982, NWK accepted
the plant. Since then, REA 2 has been in
operation without significant interrup-
tions, effectively reducing SOz emissions
of the power plant.
The Sulf-X Process
Edward Shapiro
Pittsburgh Environmental
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Systems, Inc.
Pittsburgh, PA
William Ellison
Ellison Consultants
Monrovia, MD
This paper reports the status of
development of Sulf-X technology for
FGD and reviews the design and applica-
bility of the process in boiler service firing
diverse coal fuels. Details are given of
process chemistry, design and operation,
economics, and past and future system
demonstration programs. The flexibility
and attractiveness of the technology is
shown in its use either for SOz- removal-
only or for simultaneous S0z/N0«
removal.
Franklin A. Ayer is with the Research Triangle Institute, Research Triangle Park.
NC 27709.
Julian W. Jonas is the EPA Project Officer fsee below).
The complete report consists of two volumes, entitled "Proceedings: Eighth
Symposium on Flue Gas Desulfurization. New Orleans, LA, November 1983:"
"Volume I," (Order No. PB 84-226 638; Cost: $38.50)
"Volume II," (Order No. PB 84-226 646; Cost: $37.00)
The above reports will be available only from: (cost subject to change)
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
14
*USGPO: 1984-759-102-10688
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