xvEPA
INDUSTRIAL
ENVIRONMENTAL
RESEARCH
LABORATORY
FGD
QUARTERLY
REPORT
VOL. 2 NO. 4
Winter 1978-79
RESEARCH TRIANGLE PARK, NC 27711
IN THIS ISSUE
This issue of the "FGD Quarterly Report" features EPA's
Lime/Limestone Industry Briefing Conference held on August 29
in Raleigh, North Carolina. The Conference, which afforded a
ready exchange of new information on FGD technology,
emphasized recent developments at EPA's Shawnee Lime and
Limestone Wet Scrubbing Test Facility.
This issue also includes more information on the Fifth FGD
Symposium, to be held March 5-8 in Las Vegas. The
Symposium, sponsored by 1ERL-RTP, provides a forum for
exchanging information on commercial and developing FGD
technology. Early registration for the Symposium is recom-
mended.
The "FGD Quarterly Report" is distributed by IERL-RTP,
without charge, to a list of recipients interested in FGD. Please
note that a prepaid return mailer subscription renewal notice is
included with this issue. The mailer must be returned If you wish
to continue receiving this report, even if this is the first issue you
have received. The mailer is prepaid and completely pre-
addressed. Simply tear it out, check the proper box, fold, staple,
and drop it in the mail. The optional survey questions are
designed to solicit your criticisms and suggestions for future
issues. In this way we can continue to provide you with the most
relevant information on FGD. You may also express your
comments to the EPA Project Officer or the Radian Project
Director identified on page 11 of this issue.
EPA CONFERENCE ASSESSES LIME/LIMESTONE FGD TECHNOLOGY
The Fourth Lime/Limestone Industry Briefing Conference
was held on August 29 in Raleigh, North Carolina. The con-
ference, sponsored by EPA's Industrial Environmental Research
Laboratory at Research Triangle Park (IERL-RTP), updated infor-
mation previously reported at the Fourth FGD Symposium held
in Hollywood, Florida on November 7-11, 1977. It thus afforded a
ready exchange of new information on FGD technology in the
most rapid and direct manner possible.
Approximately 120 representatives from the electric utility
industry, FGD system and equipment manufacturers, and state
and federal regulatory agencies were present to discuss recent
developments in FGD. Included were representatives from 23
different electric utilities and from all of the major FGD system
vendors.
The conference focused on lime/limestone FGD technology,
currently the most widely used method of SO, control in the U.S.
utility industry. A recent survey (EPA-600/7-78-051b, see FGD
Reports and Abstracts) estimates that, as of March 1978, 30 lime
or limestone slurry scrubbing systems were in operation at U.S.
power plants, with an additional 35 systems under construction
and 16 in the planning stage.
Lime/limestone processes have demonstrated relatively low
operating costs and a high reliability established during extensive
research, development, and demonstration (RD&D) programs.
The conference emphasized one of the most important RD&D
programs, the prototype testing at EPA's Alkali Wet Scrubbing
Test Facility, located at the Tennessee Valley Authority's (TVA's)
Shawnee Steam Plant near Paducah, Kentucky. Other research
efforts were also discussed at the meeting, including lERL-RTP's
time/limestone pilot plant, studies in sludge disposal, and plans
for the future.
John E. Williams, EPA's Shawnee Project Officer, noted in
his opening remarks that over recent years the emphasis of
lERL-RTP's programs has shifted from operating reliability to
other aspects of lime/limestone FGD technology. Reliable
operation at Shawnee is now routine. Many major problems of
the past, such as keeping mist eliminators clean, have been
solved. Mist eliminators at Shawnee have operated for over 7800
hours without cleaning and are now cleaned only between major
test blocks. Current RD&D efforts aim to improve the
lime/lirnestone FGD process by:
Reducing energy consumption.
Increasing SO, removal efficiency.
Improving sludge disposal properties.
Reducing overall costs.
Several papers describing these current RD&D efforts were
presented at the Conference. Brief descriptions of these papers
are given in the following paragraphs. (For a discussion of recent
tests at the IERL-RTP pilot plant, see "Recent Studies at 1ERL-
RTP's Pilot Plant" in this issue.) Copies of the Proceedings of this
Conference will be available soon from J. E. Williams, MI1<>1:
USEPA/IERL-RTP; Research Triangle Park, NC 27711.
Advanced Scrubbing Concepts Studied
at Shawnee Test Facility
EPA's Shawnee Lime and Limestone Wet Scrubbing Test
Facility has been in operation since 1972. The major contractor
and test director of the plant is Bechlel National, Inc., of San
Francisco. TVA is the facility constructor and operator. The test
site currently includes two 10-MW equivalent scrubbing systems.
One system is a venturi followed by a spray tower absorber
(V/ST), and the other is a turbulent contact absorber (TCA). The
scrubbers collectively treat approximately 14 percent of the flue
gas generated by firing medium- to high-sulfur coal.
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FGD QUARTERLY REPORT/WINTER 1978-79
ERA'S SHAWNEE TEST FACILITY
The Shawnee Test Facility permits larger scale studies of
some of the advanced scrubbing concepts which have shown
promise during tests at lERL-RTP's 0.1 MW lime/limestone pilot
plant (see the "FGD Quarterly Report," Vol. 2, No. 1). Research
at Shawnee has provided major contributions to the development
and application of lime/limestone scrubbing technology. Several
papers presented at the Conference described some of these
contributions resulting from the culmination of 6 years of
operating experience. Topics discussed included the Shawnee
lime/limestone computer program, recent tests with forced
oxidation, and operating experience from June 1977 to May
1978.
Process design alternatives (such as limestone versus lime
scrubbing, scrubber type, sludge disposal method).
Variations in independent design parameters {such as
scrubber gas velocity and L/G ratio, alkali stoichiometry,
and specific sludge disposal design).
Although the program is not intended to compute the economics
of an individual system to a high degree of accuracy, it is based
on sufficient detail to estimate preliminary conceptual design and
costs for various scrubbing systems.
The present computer program can project a complete
conceptual design package for lime or limestone scrubbing with a
TCA and any of four sludge disposal options. The program is
designed to consider any new coal-fired power units ranging in
size from 100 to 1300 MW. Equipment size and layout
configurations are estimated based on coals ranging in sulfur
content from 2 to 5 percent. A range of values was also
established for other key independent variables including
scrubber gas velocity, liquor recirculation rate, and slurry
residence time in the hold tank.
The effect of variations in any of the inputs (such as degree
of SO, removal, L/G ratio, and alkali stoichiometry) on process
design and economics may be determined. SO, removal,
stoichiometry, and L/G ratio may all be specified and results
projected. Alternatively, SO, removal and stoichiometry may be
specified and L/G calculated; or SO, removal and L/G ratio may
be specified and stoichiometry calculated.
The outputs of the overall computer program include a
detailed material balance, a detailed water balance, design
specifications for the scrubber system, and a display of overall
ponding design and costs. Additional economic outputs of the
program are:
* Specifications and costs of the process equipment by
major processing area.
A detailed breakdown of the projected capital investment
requirements.
An itemized breakdown of the projected revenue
requirements by component for the first year of system
operation.
Lifetime revenue requirements of the FGD plant.
The program will be modified as additional data from
Shawnee become available. Bechtel and TVA are currently
incorporating the results of the venturi spray tower tests at
Shawnee into a design and cost model for that option. Cost
models are also being added to the program for upstream fly ash
removal by electrostatic precipitators (ESP's), baghouse
collectors, and venturi scrubbers. Other options which may be
incorporated into the program in the future include forced
oxidation systems and series scrubbers/high alkali utilization
systems.
Computer Program Capable of FGD
Design and Cost Projections
In conjunction with the Shawnee test program, TVA and
Bechtel National, Inc., have developed a computer program
capable of projecting comparative investment and revenue
requirements for lime and limestone scrubbing systems. In a
paper entitled "Current Status of Development of the Shawnee
Lime-Limestone Computer Program," C. D. Stephenson and
R. L. Torstrick of TVA described the purpose, development,
status, and future of the computer program at Shawnee.
The computer program has been developed to estimate the
relative economics of lime/limestone FGD systems based on
variations in design. These variations are of two types:
Tests Demonstrate Successful Methods
of Forced Oxidation
A major drawback of lime and limestone wet scrubbing
systems is the nature of the waste material produced. In most
medium- to high-sulfur coal applications, calcium sulfite is the
predominant material in the waste sludge. Calcium sulfite
presents a serious disposal problem because of the difficulty of
dewatering. The slurry can be dewatered only to about 50 to 60
percent solids, producing an unstable, thixotropic material
unsuitable for landfill. Where space is available, the untreated
sulfite sludge has been ponded. But the pond area may be
impossible to reclaim, and in many locations sufficient space is
unavailable.
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FGD QUARTERLY REPORT/WINTER 1978-79
On the basis of the established need for improved waste
material properties and reduced disposal cost in lime/
limestone FGD systems, EPA initiated a program to develop a
simplified forced oxidation technology in 1976. Studies conducted
at the 0.1 MW IERL-RTP pilot plant in 1976 demonstrated that
calcium sulfite can readily be oxidized to calcium sulfate
(gypsum) by forced oxidation of the spent slurry (see "FGD
Quarterly Report," Vol. 2, No. 1). Gypsum settles 10 times faster
than calcium sulfite and yields a smaller volume of settled sludge.
Based on these findings, forced oxidation testing was initiated in
January 1977 at Shawnee. Results from recent tests were
presented at the conference by H. N Head, Bechtel's Project
Manager at the Shawnee Test Facility.
In his paper, "Results of Lime and Limestone Testing with
Forced Oxidation at the EPA Alkali Scrubbing Test Facility -
Second Report," Head described several systems for forced
oxidation successfully demonstrated at Shawnee. The systems
described included:
Forced oxidation in the first of two scrubber loops using
lime slurry, limestone slurry, and limestone slurry with
added magnesium oxide (MgO).
Forced oxidation with a single scrubber loop using
limestone slurry.
Forced oxidation of a scrubber bleed stream using
limestone slurry with added MgO.
The successful application of these forced oxidation systems
shows that several different approaches can be used to improve
the physical characteristics of the waste sludge. Forced oxidation
thus appears suitable for retrofit installation at the variety of FGD
plants operating throughout the U.S. The single loop configura-
tion is important because the majority of utility FGD systems,
both operating and planned, are of this type. Alternatively, some
U.S. utilities use a double loop system where the first scrubber is
designed for particle removal and the second for control of SO,.
The Shawnee tests showed that forced oxidation could be readily
applied to these double loop systems as well.
Of all methods tested, bleed stream oxidation has the least
effect on scrubber operation and facilities for bleed stream oxida-
tion would be the most practical to install. However, slower
oxidation rates and poor solids dewatering properties were
observed during tests with bleed stream oxidation at the IERL-
RTP pilot plant. One test at Shawnee indicated that these
problems may be alleviated by the addition of MgO to the lime-
stone slurry. The magnesium ion increases the liquor sulfite
concentration and buffers the slurry, permitting oxidation to
occur. Waste solids produced in these tests dewatered well. The
solids concentration in the filter cake averaged 85 percent. Addi-
tional bleed stream oxidation studies are planned at Shawnee.
Shawnee Operating Experience
Summarized
David T. Rabb, the EPA Program Site Manager, gave a
detailed summary of operating experience at Shawnee from June
1977 to May 1978. Rabb's paper, "Selected Topics from Shawnee
Test Facility Operation," discussed scrubber operation and main-
tenance, dewatering systems, and forced oxidation systems. Rabb
also described efforts to control limestone addition, and the
operational development of the FGD plant.
During the test period both scrubbers maintained a high
operational availability. The V/ST and the TCA systems operated
80 and 83 percent of the time, respectively. Systems' downtimes
were attributed primarily to boiler outages. Equipment main-
tenance accounted for less than 4 percent of the downtime for
both systems. Maintenance of scrubber internals and piping was
the primary cause of equipment-related downtime in both the
V/ST and TCA.
Dewatering of the purged slurry in lime and limestone
systems is essential to recover the dissolved scrubbing additives
and to reduce the volume of the waste product slurry. At the
Shawnee Test Facility, primary dewatering of the purged slurry is
achieved by clarifiers in both scrubbing systems. The clarifier
sludges are further dewatered in the TCA system by a solid bowl
centrifuge and in the V/ST system by a vacuum filter.
The filter caused the only serious maintenance problem in
the dewatering system. The filter cloth had to be replaced several
times because it had a tendency to bind to the drum and fray.
This particular problem is not typical of experiences at other
scrubbing facilities. Some progress was made toward preventing
cloth binding, and future operations will include further work in
this area.
Forced oxidation testing at Shawnee was described in detail
by H. N. Head (see previous discussion). Rabb described addi-
tional tests designed to determine the operating parameters
necessary to achieve "near complete" oxidation (greater than 90
percent sulfur as sulfate). The tests investigated two systems
capable of forcing oxidation. One system consisted of a
Penberthy eductor, a device which mixes air with a high velocity
slurry in a mixing chamber and jet throat. The other was a
sparge air system that bubbled air into the bottom of a slurry
tank in conjunction with simultaneous slurry agitation. The latter
system proved more favorable in terms of operating and capital
costs.
Rabb also described tests with an automatic limestone feed
control system. The automatic system was designed to maintain
a desired stoichiometric limestone feed based on inlet SO, level
and gas flow rate. Limestone addition was effectively controlled
during normal fluctuations of SO, inlet concentrations. However,
the control system could not compensate for unusually large
fluctuations in inlet SOi levels.
In conclusion Rabb described a few of the many develop-
ments and improvements made during the past 6 years of opera-
tion at Shawnee. These include infrequent mist eliminator
plugging and effective slurry pumps. Another major improvement
has been the ability to measure accurately oxygen levels in the
inlet flue gas, process pH, and SO, concentration. Reliable
density meters and magnetic flow meters have permitted close
monitoring of other operating parameters.
Test Plans and FGD Waste Disposal
As a result of the tests demonstrating forced oxidation at the
Shawnee Test Facility, TVA plans to demonstrate forced oxida-
tion at a full-scale facility at the Widows Creek Steam Plant.
Plans for the Widows Creek testing were described in a paper by
J. L. Crowe and G. A. Hollinden of TVA, and T. Morasky of the
Electric Power Research Institute (EPRI). Their paper, "Status
Report of Shawnee Cocurrent and DOWA Scrubber Projects and
Widows Creek Forced Oxidation," also discussed two advanced
FGD systems which are now being prepared for testing at
Shawnee. The first system uses a recurrent scrubber which has
the potential advantage of lower capital costs as compared to
conventional countercurrent scrubbers. The other advanced FGD
system is the DOWA process, developed in Japan and marketed
in the U.S. by Universal Oil Products (UOP). The DOWA process
produces a high quality gypsum waste product with potential
commercial value.
Several other papers addressed the topic of FGD waste
disposal. Current landfilling and ponding concepts were sum-
marized in a paper by J. Rossoff, P. P. Leo, and R. B. Fling of
the Aerospace Corporation. J. W. Barrier of TVA described the
cost estimates and conceptual designs for six different methods of
FGD waste disposal. A paper distributed by J. W. Jones of EPA
discussed the current status of disposal technology, and the
federal regulatory framework for disposal of coal ash and FGD
waste. The paper also summarized the significant achievements
of EPA's Energy/Environment Research and Development (R&D)
Program and concluded with a description of trends in both the
R&D and regulatory programs.
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FGD QUARTERLY REPORT/WINTER 1978-79
FIFTH FGD SYMPOSIUM SCHEDULED FOR MARCH
The Fifth FGD Symposium will be held March 5-8, 1979, in
Las Vegas, Nevada. The Symposium, sponsored by IERL-RTP,
will provide an opportunity for exchanging data and information
relevant to commercial and developing FGD technology. Presen-
tations will cover a variety of topics, including the status and
impacts of new legislation, utility and industrial FGD applica-
tions, SO, control alternatives, and the status of FGD in Japan.
More than 1000 participants are expected to attend the 4-day
symposium. Attendees will include utility representatives, FGD
system owners and operators, vendors, developers, researchers,
and regulators. General Chairman of the Symposium will be
Richard D. Stern, Chief of IERL-RTP*s Process Technology
Branch. C. J. Chatlynne, also of IERL-RTP"s Process Technology
Branch, will serve as Vice-Chairman. Franklin A. Ayer, of the
Research Triangle Institute, will again be Symposium
Coordinator.
The Fifth Symposium will incorporate some of the program
ideas from previous FGD symposia, and will emphasize utility
and industrial FGD applications. Waste disposal alternatives and
experiences will be addressed in each session where appropriate
rather than in separate sessions.
The Symposium program is being finalized, and the agenda
will be mailed to registrants soon. The program will be divided as
follows:
Opening Session
Introductions, Welcome, and Keynote Address.
Health Effects of SO,.
Economic and Energy Impacts of FGD.
Panel Discussion: Impact of Recent Air, Water, and Solid Waste
Legislation
* Overviews.
EPA's Approach to Implementation.
Potential Impacts.
Economics and Options
« Interagency FGD Evaluation (EPA/DOE).
Energy and Economics of FGD.
Combined Coal Cleaning and FGD.
Utility Applications
Utility State-of-the-Art.
EPA Support to Lime/Limestone FGD.
Utility Operating Experience.
Sludge Disposal Alternatives.
* Conventional Combustion Environmental Assessment.
Combined Nitrogen Oxide and Sulfur Oxide Control.
Status of Japanese Utility and Industrial FGD Technology.
Industrial Applications
Industrial State-of-the-Art.
' Industrial Operating Experience.
Panel Discussion: FGD for Potential Industrial Boiler NSPS
* Status.
Potential Impacts.
Special Evening Session: Panel Discussion on Operating Experi-
ence and Process Improvements in Commercial FGD
Systems.
Registration fee for the Fifth FGD Symposium is $35, which
includes preprints of Symposium papers, and Proceedings of the
Symposium. For information concerning the technical content of
the Symposium, contact C. J. Chatlynne, IERL-RTP (919) 541-
2915 or (FTS) 629-2915. Advance registration forms and hotel
reservation information may be obtained from Franklin A. Ayer,
Research Triangle Institute, Research Triangle Park, North
Carolina 27709, (919) 541-6260. Early registration is recom-
mended. Registration at the Symposium will be from 3 p.m.,
March 4, to 12 noon, March 5.
RECENT STUDIES AT IERL-RTFS PILOT PLANT
Recent testing at lERL-RTP's lime/limestone FGD pilot plant
has involved two main areas of investigation. One is the use of
adipic acid as an additive for improving SO, removal efficiencies
while forcing oxidation. The other is replacing makeup water
with simulated cooling tower blowdown as a means of further
reducing fresh water retirements for FGD and improving the
overall water management in a power plant. Results in both
areas of inquiry were reported by R. H. Borgwardt at EPA's
Lime/Limestone Industry Briefing Conference (see the feature
article in this issue).
In summarizing the effects of adipic acid as a scrubber
additive, Borgwardt noted that both SO, removal efficiency and
limestone utilization improved. The ability of adipic acid to
enhance SO, removal was not affected either by oxidation or by
high chloride concentrations in the scrubbing liquor. Physical
properties of the oxidized slurry (such as settling and filterability)
were not significantly different from those of slurries obtained in
the absence of adipic acid.
In other tests the fresh water makeup was replaced by a
sodium sulfate solution, simulating the cooling tower blowdown
liquid. The goal of these tests was to assess the effect of the
sodium sulfate addition on scaling. With an average sodium
concentration of 15000 ppm in the scrubbing liquor, the problem
o( sulfate scaling could be controlled by reducing inlet SO, levels
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FGD QUARTERLY REPORT/WINTER 1978-79
to 2500 ppm. At higher concentrations of inlet SOt, scaling con-
sistently occurred on the bottom of the scrubber.
Tentative conclusions from these studies are:
Adipic acid has clear merits as an additive for improving
SO, removal efficiencies in scrubbers using forced
oxidation.
An FGD system can be operated with full replacement of
the makeup water with cooling tower blowdown when the
concentration of Sd absorbed per volume of circulated
liquor (SO, make-per-pass) is maintained below 8
mmole/f.
Combined Effects of Adipic Acid
Addition, Forced Oxidation,
and Water Treatment
Studies conducted after the Lime/Limestone Conference
examined the combined effects of adipic acid, forced oxidation,
and water treatment in a single-loop limestone scrubber. Adipic
acid increased the overall SO, scrubbing efficiency from 84 to 92
percent, thus showing a positive effect on scrubber performance
in the presence of high concentrations of dissolved salts in the
scrubbing liquor (up to 32000 ppm Na* and 25000 ppm Cl").
These effects are in accord with the results of earlier tests in
which sodium sulfate was not added.
Material balance studies indicated that about 58 percent of
the adipic acid was not accounted for, even when all possible
liquor losses were considered. Side reactions may be occurring
which degrade substantial amounts of the adipic acid to the
volatile valeric acid. Additional material balance tests are
underway, with and without forced oxidation, to verify this
hypothesis.
Adipic acid had a slightly negative effect on the physical
properties of the oxidized sludge. The settling rate was reduced
by 30 percent, and fllterability was reduced from 84 to 79 percent
solids.
The tentative conclusion of these studies is that the combina-
tion of adipic acid, forced oxidation, and water treatment appears
feasible, particularly in spray tower absorbers which characteris-
tically operate at a low SO, make-per-pass. Such an approach
would maximize water use and eliminate the uncontrolled
discharge of soluble salts.
Future plans for the pilot plant include a limestone "type and
grind" test program. Four different limestone types selected to
give a wide range of expected reactivities will be tested at coarse
and fine grinds. Eleven tests are planned for the four limestones
over a 22 week period. The tests will compare the limestone
stoichiometries required for a given SO, removal efficiency.
Prospects for improving sludge quality without forced oxida-
tion will be evaluated at the pilot plant after the limestone type
and grind testing, A recent model developed by Radian
Corporation ("Development of a Mathematical Basis for Relating
Sludge Properties to FGD-Scrubber Operating Variables," se« the
"FGD Quarterly Report," Vol. 1, No. 2) will be used to select and
evaluate scrubber modifications that may result in the growth of
larger calcium sulfite crystals.
Other future plans call for the evaluation of another additive,
sodium thiosulfate, as a possible oxidation inhibitor. If small
amounts are effective in reducing oxidation when added to
commercial lime, prospects for unsaturated operation will be
improved.
One of the two scrubbers at IERL-RTP will be converted to a
sodium-based dual alkali system later this year. This scrubber
will be used to provide experimental support for EPA's full-scale
dual alkali demonstration facility at Louisville Gas and Electric
Company's (LG&E's) Cane Run Station.
For more Information on the IERL-RTP pilot plant, contact
R. H. Borgwardt, (919) 541-2336 or (FTS) 629-2336. (See also
the "FGD Quarterly Report," Volume 2, Nos. 1 and 2.)
INDUSTRIAL BOILER NSPS
EPA's Office of Air Quality Planning and Standards
(OAQPS) is developing New Source Performance Standards
(NSPS) for industrial boilers. In support of this effort, IERL-RTP
is sponsoring a series of Technology Assessment Reports (TAR's)
to determine the applicability of various emission control tech-
nologies to industrial boilers. OAQPS will use the TAR's to
produce a Standard Support and Environmental Impact State-
ment (SSEIS). This report will evaluate the economic and
environmental impacts of specified emission control technologies
and alternative regulatory strategies.
The following technologies are being considered for TAR's:
Oil Cleaning and Existing Clean Oil (Catalytic, Inc.).
Coal Cleaning and Existing Clean Coal (Versar, Inc.).
Synthetic Fuels (Radian Corp.).
Fluidized Bed Combustion (GCA Corp.).
NOx Combustion Modification (Acurex Corp.).
* NOx and NOx/SOx Flue Gas Treatment (Radian Corp.).
Flue Gas Desulfurization (Radian Corp.).
Paniculate Control (GCA Corp.).
A comprehensive assessment report will be prepared
following completion of the individual TAR's. The report will
describe methods for integrating the technologies to achieve
optimum multi-pollutant control. OAQPS subsequently will study
the impact of various control options. These studies ultimately
will lead to the establishment of NSPS for industrial boilers.
Acurex Corporation is assisting OAQPS and IERL-RTP in this
overall effort.
As shown above, FGD processes are among the technologies
being considered. Radian Corporation is preparing the
technology assessment report on these processes. The report will
address the following topics:
* Emission Control Techniques.
Candidate Systems for Optimum Emission Control.
* Control System Costs.
* Energy Considerations.
Environmental Considerations.
Emission Source Test Data.
Cost, energy, and environmental assessments will be made
for a variety of standard boilers. Seven standard boiler types will
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FGD QUARTERLY REPORT/WINTER 1978-79
be considered, including packaged and field-erected boilers
burning natural gas, stoker or pulverized coal, or distillate or
residual oil, with capacities of 16-211 GJ/hr (15-200 x 10'
Btu/hr). Coal-fired boilers will be evaluated based on high and
low sulfur Eastern and low sulfur Western coal feeds.
The final report on the assessment of FGD processes should
be available in early 1979. The comprehensive assessment report
on optimum multi-pollutant control systems should be available
in the Fall of 1979. (It should be noted that consideration of a
technology for a standard does not imply that the ultimate
standard will be based on that technology.)
Currently, background information is being compiled on
industrial boiler populations and emissions. Information for
assessing the best available control technology is being solicited
from users and manufacturers.
The proposed NSPS for industrial boiler emissions are
scheduled for publication in October 1980. For additional
information on the TAR's, contact the 1ERL-RTP Project Coordi-
nator, J. D. Mobiey (919) 541-2915 or (FTS) 629-2915. Further
information on the SSE1S and NSPS is available from C. B.
Sedman, OAQPS/ESED, (919) 541-5213 or (FTS) 629-5213.
(See also the "FGD Quarterly Report," Vol. 1, No. 3 and Vol. 2,
No. 3, for an account of EPA's review of NSPS for utility boiler
Sd emissions.)
RESULTS OF DUAL ALKALI PROTOTYPE TEST PROGRAM
The final report in a three-volume series is available
describing a program conducted by Arthur D. Little, Inc. (ADL)
for IERL-RTP to evaluate the Dual Alkali FGD Process. (See
FGD Reports and Abstracts, "Final Report: Dual Alkali Test and
Evaluation Program: Volume III. Prototype Test Program Plant
Scholz," EPA-600/7-77-050c.) The study evaluated process
chemistry and characterized operating parameters for the
sodium-based scrubbing process with the goal of defining the
viability, capabilities, and limitations of the technology. Earlier
Volumes I and II (EPA-600/7-77-050a and b), which gave the
restilts of laboratory and pilot plant tests conducted at IERL and
ADL laboratories, were described in the "FGD Quarterly Report,"
Volume 2, Number 3.
Volume III gives results of a prototype test program
conducted at Gulf Power Company's Plant Scholz in Sneads,
Florida. The 20-MW prototype system used in the test program
was designed and built by Combustion Equipment Associates
(CEA) and ADL for Southern Company Services, Inc., and Gulf
Power. It included a venturi scrubber, a multi-tray absorption
tower, a two-stage regeneration reactor in which lime is added to
precipitate calcium sulfite/ sulfate solids, and a thickener plus
rotary drum vacuum filter for waste solids dewatering.
The prototype system started up in February 1975 and
operated for 17 months (including start-up and shakedown).
Three definite periods of operation occurred during this time,
with distinctive coal compositions, flue gas conditions, and
characteristics of system operation. During the first 6 months the
boiler burned low sulfur coal. Average flue gas concentrations of
SO, and oxygen were 1050 ppm and 7.5 percent, respectively. In
the second period of operation, lasting from September 1975
through January 1976, the electrostatic precipitator (ESP) was in
service for partlculate removal. The boiler load was relatively
stable. The SO, and oxygen levels in the flue gas were 1250 ppm
and 6.0 percent. In the third period of operation, some tests were
done at fluctuating gas loads representative of normal load
swings, and some were done with the ESP out of service to
evaluate the effects of fly ash on system performance. The
average SO, concentration in the flue gas was 2250 ppm.
Oxygen levels averaged 6.5 percent.
The report gives detailed results of system performance
describing sulfur dioxide and particulate removal, lirne utilization,
sulfite oxidation, sulfate precipitation, waste cake properties,
soda ash makeup, power consumption, and operability/
reliability. The following are significant highlights of the test
program:
* Sulfur dioxide removal in the dual alkali system operating
in both concentrated and dilute active sodium modes
averaged 96 percent using both the venturi and the
absorber and 91 percent with the venturi alone.
Lime utilization averaged 93 percent during high-sulfur
coal tests and % to 97 percent during low-sulfur coal
tests. The difference is attributed to the shorter regenera-
tion reactor residence time at the higher feed forward
rates required with high-sulfur coal.
Some 80 to 95 percent of total sulfite oxidation in the
system occurred in the scrubber circuit. With low- and
medium-sulfur coals, 20 to 45 percent of the SO, removed
was oxidized. With high-sulfur coal, the oxidation rate was
10 to 25 percent of the SO, removal rate.
Calcium sulfate was coprecipitated with calcium sulfite at
levels as high as 25 percent of the total calcium sulfur
salts. This indicates that sulfate is removed from the
system (precipitated) fast, enough to keep up with the
oxidation rates anticipated for most medium- and high-
sulfur coal applications.
During closed loop operation, the sodium (soda ash)
makeup rate required to compensate for losses in the
waste solids and losses due to leaks in the system was
about 8 percent of the SO, removal rate. Losses accounted
for in filter cake were about 7 percent of the SO, removal
rate, indicating good closure of the sodium material
balance.
The power consumed by the equipment components of a
typical dual alkali scrubbing/regeneration system was
about 1 percent of boiler capacity.
During 17 months of testing, the system exhibited an
overall availability of about 70 percent. Most of the
downtime occurred due to mechanical problems and delay
in receipt of replacement parts. During the three operating
periods (covering about 14 months) availability averaged
about 90 percent.
Equipment and instrumentation problems were mechanical,
and most were resolved by simple operating adjustments
and equipment modifications. Fiberglass filter drum
structural failures, vessel lining erosion, rubber lined valve
erosion, and product solids buildup in the first stage
reactor occurred but did not influence system operability.
Further information on the dual alkali prototype tests can be
obtained from the IERL-RTP Project Officer, Norman Kaplan,
(919) 541-2556 or (FTS) 629-2556. (See also the FGD Reports
and Abstracts in this issue.)
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FGD QUARTERLY REPORT/WINTER 1978-79
EPA EVALUATES FIRST APPLICATION OF R-C/BAHCO SCRUBBER IN U.S.
In order to meet Ohio's SO, emissions regulations, the U.S.
Air Force contracted with Research-Cottrell, Inc., (R-C) to
design, erect and install an R-C/Bahco scrubber at Rickenbacker
Air Force Base (AFB) in Columbus, Ohio. This combined FGD
and particulate removal system is the first Bahco installation in
the U.S., and its first application worldwide on a coal-fired boiler.
A report prepared by R-C ("EPA Evaluation of Bahco Indus-
trial Boiler Scrubber System at Rickenbacker AFB," EPA-600/7-
78-115) describes the results of a comprehensive test program to
characterize the performance of the system in handling flue gas
from coal-fired boilers. The results show that this system is
capable of controlling both paniculate and SOt emissions from
the combustion of high sulfur (2 to 4 percent) midwestern coal at
firing rates from 21 x 10* to 211 x 10J MJ/hr (20 to 200 million
Btu/hr).
Collection efficiency as a function of particle size was deter-
mined over a wide range of flue gas flow rates and venturi pres-
sure drops. Particle emissions were reduced to as low as 0.06
g/MJ(0.151b/10* Btu).
The results of lime tests indicate that SO, removal was con-
trolled only by the lime-SO, stoichiometry. Other operating vari-
ables such as gas flow, pressure drops, liquid rates, and solids
concentration had essentially no effect on SO, removal efficiency.
This shows that good gas/liquid contact is maintained over the
entire operating range of the system. SOi emissions were reduced
to as low as 0.04 g SO./MJ (0.1 Ib SO./10' Btu) with lime.
The limestone tests were essentially a duplication of the lime
tests. SOi emissions were reduced to as low as 0.26 g SO,/MJ
(0.6 Ib SO,/10' Btu). The results show that SO, removal with
limestone above 90 percent in the system is not practical since
limestone utilization drops to approximately 60 percent. Most
industrial boiler applications, however, require SO, removal well
below the 90 percent level. For such requirements the use of
limestone will accomplish adequate SO, removal at a reagent
cost substantially below that for lime.
During the test period, the gas from the combustion of 25
Gg (27,216 tons) of 2.5 percent sulfur coal was treated. The total
cost for utilities, reagents, supplies and operating labor was $5.07
per ton of coal burned. Maintenance, labor and materials added
$0.21 to the cost for a total of $5.28 per ton of coal burned. An
operating cost of $4.06 per ton can be achieved if limestone is
used as the reagent and fan settings and makeup water consump-
tion are optimized.
The report indicates that the system performs satisfactorily
in six important areas:
SO, removal efficiency.
Paniculate removal efficiency.
Scrubber reliability.
* Ease of operation.
Minimal routine maintenance requirements.
Moderate operating costs.
Operation of the system required less than 2000 man hours
per year. During the test program, the system experienced down-
time due to auxiliary equipment defects, an inadequate spare
parts inventory, and minor system modifications. Based on the
observations made during the test programs, it is projected that
the system should operate 95 percent or more of the time in the
future.
Further information regarding this study is available from the
EPA/IERL-RTP Project Officer, J, E, Williams, (919) 451-2483 or
(FTS) 629-2483. (See also the FGD Reports and Abstracts of this
issue.)
REVEGETATION OF FGD DISPOSAL PONDS
Under an interagency agreement with EPA, the Tennessee
Valley Authority (TVA) is assessing the disposal and utilization of
sludge produced by nonregenerable FGD processes. Several
studies are being conducted as part of the overall TVA project,
including:
Study of fertilizer production from lime/limestone FGD
sludges.
Study to correlate scrubber operation with sludge charac-
teristics.
Study to determine disposal methods for waste products
from fluidized bed combustion (FBC) processes.
Study for revegetation of FGD sludge disposal ponds.
As part of this last study, several trees have been planted at
two lime/limestone FGD sludge disposal pond sites. The Colbert
site is near Muscle Shoals, Alabama. A total of 48 trees (8 each
of 6 species) were planted at this site in the spring of 1977. Of
these, 73 percent appeared to survive the first year. Survival
during the first year was comparable where trees were planted
directly in sludge or in topsoil layered over sludge. Cottonwood
and sycamore showed remarkable growth; European alder and
automn olive showed signs of stress but appeared to be well
established. After the first year, survival rates for all species were
generally greater where trees had been planted in topsoil layered
over sludge.
At the Shawnee site near Paducah, Kentucky, nine species of
deciduous trees were planted in April 1978. One group was
planted directly in the sludge and a second in holes filled with
municipal sewage sludge. Although rainfall was adequate shortly
after planting, conditions became extremely dry in May and June,
resulting in appreciable leaf drop and some mortality. Despite
this adversity, five species showed survival rates of 70 percent or
greater when checked at the end of June 1978. By September,
however, there was an apparent high mortality among all tree
species with the exception of black locust. Dry conditions during
the hot summer months were the likely cause for poor survival.
Some trees may have survived despite the leaf drop, but this
cannot be determined until next spring when new growth begins.
The TVA studies are continuing. Additional revegetation
studies with various perennial grasses and legumes are underway.
Plans also include a comparison of revegetation schemes on a
stabilized and nonstabilized pond. For more information, contact
M. C. Osborne, EPA/IERL-RTP, (919) 541-2898 or (FTS) 629-
2898.
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FGD QUARTERLY REPORT/WINTER 1978-79
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 Technica! Information Service
U, S. Department of Commerce
Springfield, Virginia 22161
(703) 557-4650
(FTS) 557-4650
EPA/1ERL-RTP reports are available free, as supplies permit,
through 1ERL-RTP*S Technical Information Service. The address
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
EPA Evaluation of Bahco Industrial Boiler Scrubber
System at Rickenbacker AFB.
E. L. Biedell, R. J. Ferb, G. W. Malamud, C. D. Ruff, and N, J.
Stevens, Research-Cottrell, Inc., Bound Brook, New Jersey, June
1978. EPA-600/7-78-115. (NTIS No. 286 611.) EPA Project
Officer: J. E. Williams, IERL-RTP.
The report gives results of an 18-month evaluation of the R-
C Bahco combined flue gas desulfurization and participate
removal system on a stoker-fired industrial boiler at
Rickenbacker AFB, Ohio. Particulate emissions were reduced to
as low as 0.15 Ib million Btu. SO, emissions were reduced to as
low as 0.1 Ib/ million Btu with lime and 0.2 Ib, million Btu with
limestone while burning 2-4% sulfur midwestern coal at firing
rates from 20 to 200 million Btu hr Operating costs, including
maintenance, were $5.28 per ton of coal burned for lime and
$4.27 per ton for limestone, exclusive of capita) costs. There were
no problems with scale formation or plugging with either reagent.
The system met all emission and operating cost guarantees.
Economic Evaluation of Stack Gas Desulfurization
for a Power Plant Located in the Mohawk Valley
Region of New York State; Final Report.
J. M. Genco and H S. Rosenberg, Battelle Columbus Labs.,
Ohio, February 1977. (NTIS No. PC A06/MF A01.)
A parametric analysis was performed to determine the capital
and annualized cost of the flue gas desulfurization (FGD)
processes for proposed coal-fired power plants located in the
Mohawk Valley region of New York State. The cases considered
were three 800-MWe units to be completed in 1985, 1986, and
1987 or, alternatively, two 1200-MWe units to be completed in
1985 and 1987. The variables selected for the parametric
analysis were (1) type of FGD process, (2) size of power plant, (3)
sulfur content of the coal, (4) inflation rate, (5) interest rate, (6)
construction escalation rate, and (7) capitalization rate. The
latter three variables are not independent in that they are directly
tied to the inflation rate.
SYSTEM SURVEYS
Final Report: Dual Alkali Test and Evaluation
Program: Volume HI. Prototype Test Program
Plant Schote.
C. R. LaMantia, R. R. Lunt, J. E. Oberholtzer, E. L. Field, and
J. R. Valentine, Arthur D. Little, Inc., Cambridge,
Massachusetts, May 1977. EPA-600/7-77-050C. (NTIS No.
272 109.) EPA Project Officer: N. Kaplan, IERL-RTP.
Volume III of the report covers Task III of a three-task program
to investigate, characterize, and evaluate the basic process
chemistry and the various operating modes of sodium-based dual
alkali scrubbing processes. The tasks were: 1, laboratory studies
at both Arthur D. Little, Inc. (ADL) and IERL-RTP; II, pilot plant
operations in a 1,200 scfm system at ADL; and III, a prototype
test program on a 20 MW dual alkali system at Plant Scholz,
Dual alkali system operating modes on high and low sulfur fuel
applications investigated included: concentrated and dilute dual
alkali systems, lime and limestone regeneration, and slipstream
sulfate treatment schemes. For each mode, the dual alkali
process was characterized in terms of SO, removal, chemical
consumption, oxidation, sulfate percipitation and control, waste
solids characteristics, and soluble solids losses.
EPA Industrial Boiler FGD Survey: Third Quarter,
1978.
J. Turtle, A. Patkar, D. Welch, M. Heasling, and M. Eckstein,
PEDCo Environmental, Inc., Cincinnati, Ohio, November 1978.
EPA-600/7-78-052c. (NTIS No. 288 204.) EPA Project Officer:
R. M. McAdams, IERL-RTP.
The report presents detailed technical information concerning
application of flue gas desulfurization (FGD) systems to industrial
boilers. Design and operation data are presented for 161 FGD
control systems (121 of them currently operational), designed to
control SO, emissions from 147 Industrial boilers at 57 plants.
With a 1978 capacity of 9.3 million scfm, an average of more
than seven new FGD systems have been put on line each year
since 1972. Information in the report was obtained by a survey of
plant personnel, control system vendors, regulatory agencies, and
consulting engineering firms. The data are given in two types of
tables: one gives summary information; the other, detailed
information. Summary tables present information as a function of
control process, control system vendor, disposal technique,
operational status, startup date, and flue gas capacity. Detailed
Information includes: control system design, economics,
operating experience, problems and solutions, waste disposal
techniques, and maintenance practices.
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FGO QUARTERLY REPORT/WINTER 1978-79
EPA Utility FGD Survey: February-March 1978.
N. Gregory, G. Isaacs, B. Laseke, M. Melia, A. Patkar, and M.
Smith, PEDCo Environmental, Inc., Cincinnati, Ohio, June 1978.
EPA-600/7-78-051b. (NTIS No. 287 214.) EPA Project Officers:
N. Kaplan, IERL-RTP; and J. C. Herlihy, OSSE.
The report is an updated supplement to EPA-600/7-78-051a
(NTIS No. 279 Oil) and should be used In conjunction with it. It
presents 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. It presents data on system design, fuel sulfur
content, operating history, and actual performance. It discusses
problems and solutions associated with the boilers and FGD
systems. Process flow diagrams and FGD system economic data
are appended to the report.
fly ash and on the behavior of such fly ash in scrubbing systems;
and to determine whether sufficient data are available to develop
guidelines and specifications for future scrubbing systems based
upon fuel and ash analyses and boiler design information. Data
from five pilot plants and 19 full-scale systems (about 4,100 MW
of boiler generating capacity fired with tow sulfur Western coals)
were reviewed and summarized. Data analysis performed as part
of the study concentrated on unique aspects of alkaline fly ash
scrubbing systems; i.e., the behavior of alkaline fly ash in
scrubbing systems and approaches to predicting ash behavior
based on fuel and ash characteristics. Scrubbing system
performance characteristics Investigated include: partfculate
removal, SO, removal, ash alkali and supplementary alkali
utilization, oxidation, scaling, water balance, waste properties,
and performance of materials. Additional data and procedures
are required in the following areas in order to predict scrubbing
system performance: ash reactivity and alkalinity (prediction of
these properties without pilot plant operations); waste solids
(chemical and physical properties); and the performance of
materials of construction in scrubbing service with particular
emphasis on plastic linings.
SO2 Abatement for Stationary Sources in Japan.
Ando, J., Chuo University, Tokyo, Japan, November 1978. EPA-
600/7-78-210. (NTIS No. unavailable.) EPA Project Officer: J. D.
Mobley, IERL-RTP.
Serious air pollution problems in Japan during the 1960's have
caused the Japanese government to regulate SOx emissions.
Several technologies are being developed, including production of
low sulfur gas from coal, fuel desulfurization and fluidized bed
combustion. However, the predominant methods currently used
for SOt control in Japan are burning low sulfur fuels and flue gas
desulfurization (FGD). Development and application of FGD
technology in Japan have preceded similar development in other
countries resulting in a significant reduction in ambient SOt
levels. The stringent, daily average ambient standard of 0.014
ppm has almost been achieved. There are several types of FGD
systems currently in use in Japan including wet lime/limestone,
indirect and modified lime/limestone, regenerable, and simul-
taneous NOx/SOx. These processes have been proven to operate
satisfactorily on a commercial scale. Both SO, removal and
operability are typically over 90 percent. Removals and opera-
bilities of 98-99 percent can be achieved at higher costs.
RESEARCH AND DEVELOPMENT
Application of Scrubbing Systems to Low
Sulfur/Alkaline Ash Coals: Final Report.
C. R. LaMantia, R. R. Lunt, I. L. Jashnani, R. G. Donnelly,
E. Interess, L. R. Woodland, and M. E. Adams, Arthur D. Little,
Inc., Cambridge, Massachusetts, December 1977. (NTIS No.
PC A17/MFA01.)
SYSTEM BY-PRODUCTS
State-of-the-Art of FGD Sludge Fixation: Final
Report.
W. A. Duvei, Jr., W. R. Gallagher, R. G. Knight, C. R. Kolnrz,
and R. J. McLaren, Michael Baker, Jr., Inc., Beaver,
Pennsylvania, January 1978. (NTIS No. PC A12/MF A01.)
Thirty-one fully operational flue gas cleaning electric utility
lirne/limcstone and alkaline fly ash wet scrubbing systems were
evaluated to determine the practical significance of FGD sludge
fixation. Five commercial sludge fixation installations are in
operation. Other disposal practices are widespread and
acceptable. Nine installations are landfilling wastes using various
types of processing while 17 are using ponding for dewatering
and ultimate disposal. Of 16 vendor companies evaluated, only
two 1U Conversion Systems (IUCS) and Dravo Corporation
have demonstrated fully commercial capability. The other
vendors have little or no FGD waste experience. Both IUCS and
Dravo products exhibit lower permeability, greater strength, and
overall improved physical, chemical, and engineering properties
compared to untreated sludges. Dravo has a full-scale, 1650 MW
facility; IUCS has four installations totaling 1818 MW. Estimated
30-year levelized incremental sludge fixation revenue require-
ments are $6.90 and $2.50 per dry ton of sludge solids for wet
disposal (ponding) and dry disposal (landfilling), respectively.
These costs are not highly site-dependent and can b« applied
generally. Byproduct recovery/utilization concepts were found to
be technically feasible but not economically competitive at this
time. The most promising concepts are utilization of fixed sludge
as a construction material, production of by-product gypsum with
utilization in agriculture and wallboard manufacturing, and mine
reclamation.
The objectives of this study were to collect and evaluate available
information on low sulfur Western coals which produce alkaline
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F6D QUARTERLY REPORT/WINTER 1978-79
Disposal of Flue Gas Cleaning Wastes: EPA
Shawnee Field Evaluation Second Annual
Report.
R. B. Fling, W. M. Graven, P. P. Leo, and J. Rossoff, The
Aerospace Corporation, Los Angeles, California, February
1978. EPA-600/7-78-024. (NTIS No. 282 246). EPA Project
Officer: J. W. Jones, IERL-RTP.
The report describes progress made during the first 2 years of
a Held evaluation of treated and untreated ponding techniques
for the disposal of power plant flue gas desulfurization
sludges. The evaluation utilized two 10 MW lime and
limestone flue gas scrubbers of TVA's Shawnee Power Station,
Paducah, Kentucky. Results indicate that the concentration of
total dissolved solids (IDS) in the leachate of treated ponds
was maximum immediately after filling, or within a few
months, and was approximately half that of the input liquors.
Leachate from untreated ponds was similar, except that the
maximum was approximately the same as the TDS of the
input liquor. After 2 years, TDS in the leachates of all ponds
are between 33% and 50% of that of their respective input
liquors. Leachates from the evaluation ponds exhibit
decreasing concentrations of chloride ion, and the TDS have
stabilized at approximately gypsum saturation. Trace elements
exhibited little change. Chemically treated sludges continue to
exhibit good landfill strength and generally reduce the mass
release of sludge constituents to the subsoil by at least 2
orders of magnitude.
Assessment of Technology for Control of Toxic
Effluents From the Electric Utility Industry.
J. D. Colley, C. A. Muela, M. L. Owen, N. P. Meserole, J, B.
Riggs, and J. C. Terry, Radian Corporation, Austin, Texas,
June 1978. EPA-600/7-78-090. (NTIS No. 283 716.) EPA
Project Officer: J. W. Jones, IERL-RTP.
The report assesses the applicability of control technologies
for reducing priority pollutants In effluents from the steam-
electric power generating industry. It surveys control tech-
nologies, identifying those that have demonstrated some
control effectiveness for priority pollutants. From the
preliminary survey, the control technologies most applicable to
the utility industry were Identified. The selected control tech-
nologies were evaluated to determine their effectiveness in
reducing priority pollutants in utility streams and their
associated costs.
ACCESSORY SYSTEMS
Lime/Limestone Scrubbing Sludge Characteriza-
tion Shawnee Test Facility.
J. L. Crowe, and S. K. Seale, Tennessee Valley Authority,
Chattanooga, Tennessee, October 1977. EPA-600/7-77-123.
(NTIS No. 284 111.) EPA Project Officer: J. W. Jones, IERL-
RTP.
The report summarizes progress on a project to determine the
range of variability of the solids from scrubbers at the
Shawnee FGD Test Facility, and to attempt to correlate this
variability with plant operating conditions. Slurry and solids
characterization studies were conducted on 84 samples from
the TCA and venturi-spray tower. The solids samples generally
consisted of calcium sulfite hemihydrate (50-70%) and fly ash
(20-40%) with trace quantities of gypsum, unreacted
absorbent, and quartz. The form of the sulfite crystals was
directly related to the absorbent used (lime or limestone), but
independent of the scrubber type (TCA or venturi-spray tower).
With limestone, the sulfite crystallized as well-formed single
plates; with lime, it appeared as spherical, closely inter-
penetrating aggregates. The average size of the sulfite plates
from the limestone system was inversely related to system
stolchiometry; the lime system had no such relationship. The
fly ash in the samples consisted of solid or hollow spheres of
amorphous aluminosilicate material (sometimes containing
calcium and/or iron). Slurry sedimentation behaved in three
basic modes: clarification, zone settling, and compression
settling. Solids morphology exerted a strong influence on
settling behavior. For samples with large proportions of very
small plates or complex crystalline forms, settling was
inhibited.
Evaluation of a Sulfur Dioxide Mass Emission
Rate Monitoring System.
R. Rollins, Environmental Sciences Research Laboratory, U.S.
EPA, Research Triangle Park, North Carolina, January 1978.
EPA-600/2-78-007. (NTIS No. PB 277 394.)
An evaluation was conducted to determine the capabilities and
limitations of a commercially available monitoring system that
provides SO, mass emission rate data as a direct output. The
monitoring system was operated continuously for extended
periods at a coal-fired power plant and a sulfuric acid
production facility. Additional testing was performed at a
Simulated Stationary Source Facility to confirm some
deficiencies noted during field operations. The system's perfor-
mance was verified by comparing its output data with results
using EPA emissions measurement reference methods.
Results are presented for three performance tests at both field
sites. For the power plant tests, the monitor agreed within
20% of the accepted reference method. In the case of the
acid plant, the system accuracy was as poor as 58%.
Generally, the monitoring system performed reliably through-
out the extended test program. The system remained
operational greater than 90% of the time during the 4-month
test period.
10
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F6D QUARTERLY REPORT/WINTER 1978-79
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
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ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, N. C. 27711
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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