United States
                   Environmental Protection
                   Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
                   Research and Development
 EPA/600/S9-85/009  May 1985
v>EPA         Project Summary
                   Proceedings:
                   EPA's  Industry Briefing  on  the
                   Organic-Acid-Enhanced
                   Limestone  FGD  Process
                   (July  1984)
                   J. David Mobley
                     The proceedings document presenta-
                   tions made during an EPA-sponsored
                   industry briefing, July 19,1984, in San
                   Antonio. "TX. The brief ing dealt with the
                   status of EPA's research activities on
                   the organic-acid-enhanced limestone
                   flue gas desulfurization (FGD) process.
                   Subjects covered included: (1) a tech-
                   nical and economic evaluation of organ-
                   ic acid addition to the San Miguel FGD
                   system—results of parametric tests and
                   the utility's perspective, (2) results of
                   the first 2 years of commercial operation
                   of an organic-acid-enhanced FGD sys-
                   tem, (3) economics of retrofitting Big
                   Rivers Electric Corporation's lime-
                   based FGD system to organic-acid-en-
                   hanced limestone operations, and (4) an
                   economic evaluation of limestone and
                   lime FGD processes  for new systems.
                   The briefing provided users, architects,
                   engineers, vendors,  consultants, and
                   government personnel with a compre-
                   hensive assessment of this innovative
                   technology for controlling  SO2 emis-
                   sions.

                     This Project Summary was developed
                   by EPA's Air and  Energy Engineering
                   Research Laboratory, Research Triangle
                   Park, NC, to announce key findings of
                   the research project that is  fully docu-
                   mented in a separate report of the same
                   title (see Project Report ordering infor-
                   mation at back).
Introduction
  EPA's Air and Energy Engineering
Research Laboratory (AEERL)* periodical-
ly sponsors symposia and industry brief-
ings for the transfer of information re-
garding research, development, and ap-
plication activities with the objective of
further accelerating the development and
commercialization of technology. One of
the major AEERL efforts for  the past
several years has been advancement of
thetechnology for flue gas desulfurization
(FGD). A key element of the FGD program
has been the advancement of lime/lime-
stone wet scrubbing  technology, which
has led to the development of the organic-
acid-enhanced limestone FGD process.	
  The July 19, 1984, Industry Briefing"
was designed to provide interested people
with EPA's latest findings on the use of
organic acid in lime/limestone scrubbers.
The presentations covered testing work
performed at the laboratory, bench, pilot,
prototype, industrial, and utility scales. In
addition, an economic assessment of the
use of the technology on new and retrofit
systems was included. The presentations
were complemented by a tour of the FGD
system at  San Miguel Electric Cooper-
ative's Jourdanton Station in Jourdanton,
TX; a summary of the tour is provided as
an appendix to the proceedings.
•Formerly EPA's Industrial Environmental Research
 Laboratory, Research Triangle Park, NC.

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  More than 220 people representing
electric utilities, industrial sources, arch-
itect and engineering  firms,  vendors,
consultants, and governmental personnel
attended the briefing in San Antonio, TX.
  Abstracts of the presentations follow.
Asterisks by authors' names denote pre-
senters.

Technical and Economic
Evaluation of Organic Acid
Addition to the San Miguel FGD
System—Part 1 —Results of
Parametric Tests

Jack M. Burke*
Radian Corporation

Robert P. Metcalfe and
Robert Cmiei
San Miguel Electric
Cooperative

J. David Mobley
U.S. Environmental  Protection
Agency

  This paper summarizes the results of
organic acid addition tests at a commer-
cial FGD  system. The tests were  con-
ducted at San Miguel  Electric Cooper-
ative's 410  MW lignite-fired  Unit 1,
outside Jourdanton, TX. During the pro-
gram, several organic acid mixtures were
tested over a range of operating condi-
tions. The objective of these tests was to
determine if the use of  organic  acids
would allow San Miguel to reduce FGD
system operating costs. Based on the test
results, a cost analysis indicated that the
use of organic acid addition at San Miguel
will result in a first-year cost savings of
over $600,000.  In terms  of cumulative
net present worth, the estimated savings
over a 15-year period will be $7.2 million
1984 dollars.


Technical and Economic
Evaluation of Organic Acid
Addition to the San Miguel FGD
System—Part 2—The Utility's
Perspective

Robert Cmiel*
Robert P. Metcalfe*, and
Wade Sebby
San Miguel Electric Cooperative

  San Miguel Electric Cooperative's FGD
system started up in 1981 and immed-
iately became an area of operating prob-
lems for the  utility. After fighting major
problems for over a year, San Miguel
participated in an EPA-sponsored  study
to explore the costs and benefits  of an
organic acid  conversion to improve the
performance of  their  limestone based
FGD unit. Based on the results of the
initial study, San Miguel agreed to partic-
ipate with the EPA in a test program to
gather actual data on the conversion of a
large commercial unit  to organic-acid-
enhanced operations. Benefits include:


• Improved process operation and sub-
   stantial cost savings were estimated to
   be $7.2 million over a 15-year period.
   Current operating experiences indicate
   that this figure is low. To ensure that
   these savings are real, San Miguel will
   continue to develop and refine  its
   operating skills.

• Reduced limestone stoichiometry, ac-
   complished by reducing the operating
   pH, has resulted in better limestone
   utilization and slurry oxidation.

• Reduced  scaling and  pluggage in
   scrubber modules has increased ef-
   ficiency with less maintenance.

• Reduced scrubber waste production
   requires less operation  time for the
   system and less truck hauling time
   back to the mine.


Results of the First 2 Years of
Commercial Operation of an
Organic-Acid-Enhanced FGD
System

R. L. Glover, G. E. Brown,
J. C. Dickerman, and
0. W. Hargrove
Radian Corporation

N. Dale Hicks* and
D. M. Fraley
Springfield City Utilities

J. David Mobley
U.S. Environmental Protection
Agency

  The U.S. EPA has sponsored research
to develop organic-acid-enhanced flue
gas desulfurization (FGD) technology for
existing and new coal burning facilities. A
1981 EPA-sponsored demonstration pro-
gram at Springfield City Utilities' South-
west Power Plant (SWPP), near Spring-
field, MO, showed that adipic acid and
dibasic acid (DBA) greatly enhanced FGD
performance. SWPP has continuedto use
DBA to comply with the 1971 SO2 emis-
sions  standard under which they are
regulated. Thus, SWPP became the first
commercial-scale system to use an or-
ganic additive to enhance S02 removal.
This paper documents the first 2 years
(1982 and 1983) of commercial operation
of the DBA system at SWPP. During 1982
and 1983, SWPP averaged an SO2 emis-
sion rate of less than I.O Ib S02/106 Btu
(430 ng/J). Conversely, in 1980 (prior to
DBA addition), SWPP averaged about 5 Ib
SO2/106 Btu (2,170 ng/J). FGD system
reliability  has also  greatly  improved,
averaging 97.9 percent in 1982 and 98.7
percent in 1983, compared to 45 percent
in 1980. Overall, DBA has increased the
flexibility of the SWPP system and, most
importantly, allowed SWPP to operate in
compliance.
Economics of Retrofitting Big
Rivers Electric Corporation's
Lime Based FGD System to
Organic-Acid-Enhanced
Limestone Operations

Dennis Laslo*, Norman Ostroff,
Richard Foley, and
Donald G. Schreyer
Peabody Process Systems

J. David Mobley
U.S. Environmental Protection
Agency

  In 1982-83, Peabody Process Systems,
Inc. (PPSI) conducted pilot plant tests at
the R.  D. Green Station of Big Rivers
Electric Corporation (BREC). PPSI's final
report of the pilot testing included com-
parisons of the operating costs of a lime
based,  full-sized absorber, to a  retrofit
limestone system enhanced with dibasic
acid (DBA) or adipic acid. The site specific
changes required for BREC to convert
their existing lime FGD system  to a
limestone system enhanced by DBA or
adipic acid, and the costs of making such
a change, are described in this paper.
Results of this analysis indicated that an
annual cost savings of $2.6 million could
be achieved by  converting the existing
lime system to an adipic-acid-enhanced
limestone system, and an annual savings
of $3.1 million  could  be achieved  by
converting to a DBA-enhanced system.

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Economic Evaluation of
Limestone and Lime Flue Gas
Desulfurization Processes for
New Systems

T. A. Burnett, C. D. Stephenson,
F. A. Sudhoff, J. D. Veitch, and
R. L Torstrick*
Tennessee Valley Authority

J. David Mobley
U.S. Environmental Protection
Agency

  The preliminary-grade economics (ac-
curacy:  -15 percent, +30  percent)  of
various alternative limestone and lime
flue gas desulfurization (FGD) processes
are examined using the current design
and economic premises established for
the continuing series of economic evalua-
tions  performed by TVA for EPA. The
economics are projected using the Shaw-
nee  lime/limestone computer  model,
which is based on long-term operating
data from EPA's alkali scrubbing test
facility at TVA's Shawnee Steam Plant
near Paducah, KY. The capital investment
for the  base-case limestone scrubbing
process (500 MW, 3.5 percent sulfur coal,
1979 NSPS, spray tower, forced oxida-
tion, landfill) is $206/kW. The first-year
and  levelized annual revenue  require-
ments are 10.59 and 15.09 mills/kWh,
respectively. Costs  for the  equivalent
limestone  scrubbing  process  using  a
Turbulent  Contact Absorber (TCA) are
lower, while those for the venturi/spray
tower absorber are higher. Forced-oxida-
tion/landfill disposal has a lower capital
investment than unoxidized/pond dis-
posal for all options studied; however, the
first-year and levelized annual  revenue
requirements are slightly higher for the
forced-oxidation/landfill process for most
coal  applications. For the spray tower
limestone process to achieve a specified
SO2  removal efficiency, it is more eco-
nomical to increase the limestone stoich-
iometry and minimize the absorber liquid/
gas ratio (L/G). The use of adipic acid or
possibly dibasic acid (DBA) as an additive
to enhance S02 removal in the limestone
scrubbing  process is an economically
attractive option.

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     The EPA author. J. DavidMob/ay (also the EPA Project Officer, see below), is with
       Air and Energy Engineering Research Laboratory, Research Triangle Park, NC
       27711.
     The complete report, entitled "Proceedings: EPA's Industry Briefing on the
       Organic-A cid-Enhanced Limestone FGD Process—July 1984," (Order No. PB
       85-181  105/AS; Cost: $16.00, subject to change) will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield, VA  22161
            Telephone: 703-487-4650
     The EPA Project Officer  can be contacted at:
            Air and Energy Engineering Reearch Laboratory
            U.S. Environmental Protection Agency
            Research Triangle Park. NC 27711
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