United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park 27711
Research and Development
EPA/600/S9-917015 July 1991
Project Summary
Proceedings: 1990 SO2 Control
Symposium
Charles B. Sedman
This report compiles 110 presented
papers from the 1990 SO2 Control Sym-
posium held in New Orleans, LA, May
8-11,1990. Topics include: SO2 control
economics, furnace sorbent injection,
byproduct utilization, spray dryer tech-
nology, wet flue gas desulfurization
(FGD) and combined SOx/NOx control
technologies, and post-combustion dry
sorbent injection. Many papers present
results from full-scale operational stud-
ies, while laboratory and pilot-scale re-
search on new technologies is also em-
phasized.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Tri-
angle Park, NC, to highlight key topics
of Interest on SO2 control that are fully
documented In a separate report of the
same title (see Project Report ordering
Information at back).
Introduction
The Symposium, jointly sponsored by
the Electric Power Research Institute
(EPRI) and the Air and Energy Engineer-
ing Research Laboratory, U.S. Environ-
mental Protection Agency (AEERL/
USEPA) is held periodically to transfer
technical information and advance tech-
nology development and application for
control of SO2 emissions from fuel com-
bustion. The 1990 SO2 Control Sympo-
sium was held in New Orleans, LA, May
8-11, 1990. The proceedings from this
Symposium consist of four volumes, con-
taining 110 presented papers covering 14
technical sessions:
Session
Subject Area
1
2
3A
3B
4A
4B
4C
5
6A
6B
6C
7A
7B
International Overview
Economics
Furnace Sorbent Injection
(FSI)
Byproduct Utilization
FSI Recycle
Wet FGD Reliability
Spray Dryers
Wet Full Scale Operation
Emerging Technologies
Combined SO|(/NOX
Technologies
Wet FGD Vendor Designs
Post-Combustion Dry
Technologies
Wet FGD Research
Poster Session Misc. FGD Topics
International Developments
Four papers on international SO2 con-
trol at electric generating stations were
presented covering Japan, Canada, the
United Kingdom, and Europe. Flue gas
desulfurization (FGD) technology in Japan
dated to 1973. Currently wet FGD has
evolved with a fourth generation system
using limestone, a single oxidation and
absorption tower, and generating a gyp-
sum byproduct. A combined SO/NOx sys-
tem using activated coal char as the sor-
bent is scheduled for demonstration in
1990-91. Fluidized bed combustion is also
used in Japan but is not widespread. The
author concludes that future systems of
choice will be the dry bed, combined SOx/
NO removal system using char sorbent.
Printed on Recycled Paper
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United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park 27711
Research and Development
EPA/600/S9-91/015 July 1991
v/EPA Project Summary
Proceedings: 1990 SO2 Control
Symposium
Charles B. Sedman
This report compiles 110 presented
papers from the 1990 SO2 Control Sym-
posium held in New Orleans, LA, May
8-11,1990. Topics include: SO2 control
economics, furnace sorbent injection,
byproduct utilization, spray dryer tech-
nology, wet flue gas desulfurization
(FGD) and combined SOx/NOx control
technologies, and post-combustion dry
sorbent injection. Many papers present
results from full-scale operational stud-
ies, while laboratory and pilot-scale re-
search on new technologies Is also em-
phasized.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Tri-
angle Park, NC, to highlight key topics
of Interest on SOa control that are fully
documented In a separate report of the
same title (see Project Report ordering
Information at back).
Introduction
The Symposium, jointly sponsored by
the Electric Power Research Institute
(EPRI) and the Air and Energy Engineer-
ing Research Laboratory, U.S. Environ-
mental Protection Agency (AEERL/
USEPA) is held periodically to transfer
technical information and advance tech-
nology development and application for
control of SO2 emissions from fuel com-
bustion. The 1990 SO2 Control Sympo-
sium was held in New Orleans, LA, May
8-11, 1990. The proceedings from this
Symposium consist of four volumes, con-
taining 110 presented papers covering 14
technical sessions:
Session
Subject Area
1
2
3A
3B
4A
4B
4C
5
6A
6B
6C
7A
7B
International Overview
Economics
Furnace Sorbent Injection
(FSI)
Byproduct Utilization
FSI Recycle
Wet FGD Reliability
Spray Dryers
Wet Full Scale Operation
Emerging Technologies
Combined SO/NOx
Technologies
Wet FGD Vendor Designs
Post-Combustion Dry
Technologies
Wet FGD Research
Poster Session Misc. FGD Topics
International Developments
Four papers on international SO2 con-
trol at electric generating stations were
presented covering Japan, Canada, the
United Kingdom, and Europe. Flue gas
desulfurization (FGD) technology in Japan
dated to 1973. Currently wet FGD has
evolved with a fourth generation system
using limestone, a single oxidation and
absorption tower, and generating a gyp-
sum byproduct. A combined SOx/NOx sys-
tem using activated coal char a*s the sor-
bent is scheduled for demonstration in
1990-91. Fluidized bed combustion is also
used in Japan but is not widespread. The
author concludes that future systems of
choice will be the dry bed, combined SO/
NO removal system using char sorbent."
Printed on Recycled Paper
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Canada currently has no commercial
add-on SO2 control technologies in place,
but has considerable developmental ac-
tivities ongoing. Individual utility compa-
nies have initiated research programs to
comply with provincial SO reduction goals
by the mid 1990s. The individual research
programs for Nova Scotia Power, New
Brunswick Electric Power Commission,
Ontario Hydro (Saskatchewan) Power Cor-
poration, and Alberta Power Limited were
discussed. A full array of technologies,
many of which are detailed later in this
Symposium, were cited as candidates for
research and/or evaluation.
The United Kingdom has 70,000 MWe
of electrical generating capacity, the ma-
jority being coal-fired. Recent legisla-
tion targets 40% SO reduction by 1998
and 60% reduction by 2003, which will
result in considerable retrofit of existing
facilities.
The West German retrofit program
(GFAVO) was enacted in 1983 and has
resulted in 150 units, over 30,000 MWe
capacity, retrofitted with FGD, along with*
7400 MW of new capacity. Wet limestone,
forced-oxidation scrubbers have accounted
for 90% of FGD installations.
FGD Economics
The Economics Session emphasized the
anticipated costs of FGD retrofit for acid
rain legislation. One paper compares
spray dryer and wet FGD system costs for
hypothetical new and retrofit 500 MW
installations. Another paper summarized*
a comprehensive EPRI cost study, includ-
ing that (a) FGD costs were currently lower
(when corrected for inflation) than for pre-
vious studies, (b) a number of technolo-
gies were very close in costs per ton of
SO2 removed, and (c) 30% reduction in
wet FGD costs were obtainable by pro-
cess simplification; e.g., no spare mod-
ules, single absorbers.
A third paper detailed design changes
to reduce FGD retrofit costs, while a fourth
paper discussed the role of economics in
compliance planning strategies. The next
two papers discussed retrofit cost consid-
erations specific to the Tennessee Valley
Authority system and to 200 candidate
retrofit boilers nationwide, respectively.
The latter paper also compared proposed
U.S. retrofit economics to actual costs ex-
perienced in recent West German retro-
fits.
A seventh paper focused on second-
generation wet FGD technologies as ret-
rofit choices while the eighth and final
paper discussed strategies to comply with
imminent acid rain legislative requirements.
Furnace Sorbent Injection
Emphasis was on design and operation
of full-scale facilities. The first paper de-
scribed furnace lime injection on a 65
MWt stoker-fired boiler in West Germany
followed by a second reaction stage with
humid if ication upstream of an electrostatic
precipitator (ESP) for 90% SO2 removal.
Three papers in this session which de-
scribed experimental studies for limestone
and lime sorbents injected into furnaces,
while another paper detailed large pilot
furnace injection on a 15 MWt tangential
prototype boiler. Three papers described
activities at three demonstration sites.
Results were presented for lime injection
at the 105 MW Edgewater and 61 MWe
Whitewater Valley sites, reporting up to
50 and 72% SO2 removal, respectively.
Plans for the 180 MWe demonstration at
the Yorktown No. 2 tangentially fired boiler,
to start up in 1992, were discussed in the
final paper of this session.
Byproduct Utilization
In Session 3B, Byproduct Utilization,
eight papers were presented for waste
handling, disposal and re-use in wet FGD,
spray dryer FGD, furnace sorbent injec-
tion, and new technologies. Three papers
dealt specifically with limestone/lime wet
FGD sludge utilization as paving materi-
als, aggregates, structural concrete, gyp-
sum, and fertilizer. Other papers discussed
potential byproducts from advanced new
technologies such as gypsum and ammo-
nium sulfite. Two papers dealt with spe-
cific experience in byproduct/waste man-
agement efforts: one for the Ohio Edison
system and one covering recent experi-
ence in West Germany.
FSI Recycle
The Furnace Sorbent Injection (FSI)
Recycle Session (4A) consisted of four
presentations on the increased utilization
of calcium sorbents for in-furnace injec-
tion. One paper discussed dust collector
recycle of dry sorbent with additives; an-
other discussed similar recycle but by re-
slurrying and re-injection as a slurry into
the furnace. Two other papers discussed
more novel reactivation schemes prior to
recycleone process (ARA) steam-treats
collected solids prior to recycle into the
flue gas, while another (ADVACATE) con-
verts waste solids into calcium silicate prior
to reinjection into ductwork.
Wet FGD Reliability
Session 4B, Wet FGD Reliability, con-
sisted of eight papers covering:
designing systems for load swing (cy-
cling) service
protective linings for scrubber com-
ponents
corrosion prevention/control
effects of additives on materials of
construction
duct conversion downstream of FGD
alternatives to gas reheat for duct
corrosion prevention
Spray Dryers
Session 4C focused on large pilot- and
full-scale commercial applications of spray
dryer technology. Two papers covered
pilot experience at TVA's Shawnee facility
and EPRI's High Sulfur Test Center. One
paper described operating experience on
an 865 MWe unit using eight absorbers; a
second described vendor experience with
spray dryers worldwide. The effect of
spray dryer operation on ESP performance
was discussed in the remaining papers.
Wet Full-Scale Operation
Session 5 covered the mainstream topic
of FGD symposia, that of full-scale oper-
ating experiences of wet lime/limestone
scrubbers. The session began with an
overview of chemical additives for im-
proved operation by the Session Chair-
man. Nine papers followed on :
thiosulfate additives on three com-
mercial FGD units
sodium formate addition on pilot- and
full-scale scrubbers
performance evaluation of magne-
sium/lime, limestone, gypsum
byproduct, and limestone low sulfur
coal FGD operations
evaluation of a Chiyoda wet scrub-
ber system
scale prevention on a commercial
FGD system
laboratory evaluation of additive
losses in FGD
process modifications to improve
FGD performance
Emerging Technologies,
Combined SO^NO,
Technologies, and Wet FGD
Vendor Designs
Sessions 6A, 6B, and 6C were "mini-
sessions" consisting of abbreviated pre-
sentations of new developments in SO
control, specialized topics thought to be of
less general interest than conventional
FGD technology. The purpose of these
sessions was to expose new concepts,
while minimizing the time, thus allowing
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many topics to be discussed. Sessions
and topics covered were:
Emerging Technologies:
Parsons FGD process
FGD process using cement kiln
waste
ISPRA Mark 13A process
plasma-jet SO2 conversion
CANSOLV FGD process
anion-exchange resin dechlorini-
zation
synergistic reactor for SO2 control
Combined SOx/NOx Technologies:
overview report on SOx/NOx control
lime-urea hydrate injection
NOXSO process
combined SOx/NOx control by cata-
lytic system
combined SOx/NOx control in a wet
limestone scrubber
combined SOx/NOx by fixed-bed dry
sorbent
dry sorbent injection SOx/NO con-
trol
Wet FGD Vendor Designs:
Flakt wet FGD systems
West German FGD systems
Babcock-Hitachi "Intelligent" scrub-
ber
KRC-Noell wet FGD system
Pure air FGD process
Chiyoda wet FGD system
Post-Combustion Dry
Technologies
Session 7A, Post-Combustion Dry Tech-
nologies, focused on efforts to develop
lower cost retrofit technologies using dry
sorbents injected into the post-combus-
tion flue gas. These papers included two
discussions of dry sodium injection, four
papers discussing calcium injection, one
paper documenting a combined calcium/
sodium dry injection system, and one pa-
per describing a spray dryer within an
ESP (E-SOJ.
Wet FGD Research
Session 7B, Wet FGD Research, cov-
ers the laboratory- and small-pilot-scale
research on wet FGD being conducted
primarily at EPRI and its member compa-
nies. Topics included mist eliminator per-
formance, limestone utilization, process ad-
ditives, crystallization studies, combined
SOx/NOx control in wet scrubbers, and pro-
cess/economic models developed for in-
dustry.
Poster Session
Although not presented formally at the
podium, the 1990 SO2 Symposium con-
ducted a large poster session where FGD-
related subjects were discussed face to
face between the author and audience.
Of these, 13 submitted technical papers
which are included in the proceedings.
These topics are heavily oriented toward
research programs and vary from fly ash
effects on SO2 control, process models,
improved FGD components, additives, and
corrosion control. Also papers for non-
utility applications, especially waste incin-
erator FGD, were presented in this ses-
sion.
&LI.S. GOVERNMENT PRINTING OFFICE: 1991 - 548-02H/40030
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