USB
FGD
QUARTERLY
REPORT
INDUSTRIAL
ENVIRONMENTAL
RESEARCH
LABORATORY
VOL. 2 NO. 2
Spring 1978
RESEARCH TRIANGLE PARK, NC 27711
INTRODUCTION
The FGD Quarterly Report is part of a comprehensive
Engineering Application/Information Transfer Program on flue gas
desulfurization (FGD). The program is sponsored by EPA's In-
dustrial Environmental Research Laboratory. Research Triangle
Park, North Carolina (IERL-RTP). The report is designed to meet
four objectives: (1) to disseminate information concerning EPA
sponsored and conducted research, development, and demon-
stration (RD&D) activities in FGD; (2) to provide progress updates
on selected ongoing contracts; (3) to report final results of various
FGD studies, and (4) to provide interested readers with sources of
more detailed information.
This report features an article on industrial boiler FGD
systems, with emphasis on those FGD systems amenable to
industrial use. including operating experience to date. Also
highlighted in this issue are FGD sludge disposal studies, and
upcoming events such as the Fifth FGD Symposium.
The FGD Quarterly Report is distributed, without charge, to
recipients interested in FGD. Persons wishing to report address
changes, or initiate or cancel their free subscriptions to the FGD
Quarterly Report may do so by contacting the EPA Project Officer
or Radian Project Director named on the last page of this issue.
FGD TECHNOLOGY APPLIED TO
INDUSTRIAL BOILERS
From 1970 to 1975, use of fossil fuels in stationary combustion
sources together with industrial processes accounted for over 97
percent of the sulfur oxide (SO,) pollution in the U.S. The electric
utility industry was responsible for the majority (60 percent) of SO,
emissions. Industrial boilers contributed approximately 18 percent,
with an additional 18 percent resulting from various industrial
processes such as petroleum refining, chemicals manufacturing,
and metal refining and processing. Another 3 percent of the total
SO, pollution during this period is attributed to such miscellaneous
sources as combustion for transportation.
The application of FGD technology to utilities has already
received widespread study and documentation. Similar attention is
now being focused on the second most significant combustion
source of SO, pollution: the industrial boiler.
The number of FGD control systems applied to industrial
boilers has increased dramatically in the past 6 years due to more
stringent emissions regulations. The "EPA Industrial Boiler FGD
Survey: First Quarter, 1978," prepared by PEDCo Environmental,
Inc., (EPA-600/7-78-052a, see FGD Reports and Abstracts section)
estimates a total of 135 industrial boiler FGD systems presently
operating at 34 plant sites in the U.S. FGD units at nine plants are
under construction or in planning stages.
FGD Processes Must Meet Industrial Needs
Most of the FGD processes used to control emissions from
utility boilers could also be applied to industrial systems. There are,
however, significant differences in the latter applications.
Generally, industrial boilers operate with higher oxygen levels than
do their utility counterparts. This creates problems with certain wet
scrubbing processes (such as the Wellman-Lord) that regenerate
the scrubber liquor. The higher oxygen content of the flue gas
promotes oxidation of the dissolved sulfur species from sulfites to
sulfates. Sulfates formed in the scrubber liquor are not regenerable
and must be purged from the system.
Another feature of industrial boilers is their association with
various industrial processes. Frequently the associated processes
generate by-product streams (such as caustic wastewater or am-
monia-laden process water) which can be used as the scrubbing
liquor to absorb SO,. Such captive sources are unavailable to
utilities, which must obtain their active absorbents from outside
sources.
Finally, industrial boilers usually have lower operating
capacities than those of larger utility systems. Non-utility com-
bustion sources can thus be served with smaller-scale FGD control
equipment. Often, pre-cngineered or "package" FGD systems
requiring only one full or part-time system operator are suitable for
industrial boilers.
In certain smaller industrial applications, FGD system
reliability is hampered by the lack of emergency backup equipment.
Such equipment is too costly for these smaller installations,
although its use is well-justified in the larger utility systems.
Presently, those FGD processes most commonly applied to
industrial boilers are sodium-alkali and dual-alkali scrubbing.
Additional methods of SO, control used less frequently are the
citrate and lime/limestone processes.
Sodium alkali Scrubbing in Use
Since 1972
Sodium alkali scrubbing is a nonregenerable method of SO,
control. The flue gas is scrubbed with a solution of sodium car-
bonate, bicarbonate, or hydroxide. The absorption reaction con-
verts sulfur in the flue gas to sulfite/bisulfite and sulfate. The spent
scrubbing liquor is purged from the system and disposed of in
evaporation ponds. An alternate disposal practice is treatment
(usually by oxidation and/or neutralization) and discharge to rivers
or city sewer systems.
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FGD QUARTERLY REPORT/SPRING 1978
Since 1972 the number of sodium alkali FGD system has
increased steadily. The sodium alkali FGD process is now in
operation in at least 19 plant sites in the U.S., making it the most
prevalent method of controlling SO, emissions from industrial
boilers.
General Motors' St. Louis Plant
Sodium alkali scrubbing was the first full-scale FGD process
applied to industrial boilers. In 1972, two Arthur D. Little, Inc.,
(ADL) sodium alkali scrubbing systems were installed on two coal-
fired boilers (25-MW equivalent) at a General Motors' Plant in St.
Louis, Missouri. These SO, control systems are still operating.
Coal composition is typically 3.2 percent sulfur and 20 percent
ash. Cyclones and electrostatic precipitators (ESP's) are used for
particulate removal The SO, is absorbed in a three-stage im-
pingement tower equipped with a chevron mist eliminator. Reheat
is provided by steam coils. With an inlet loading of 2000 ppm SO,,
this system achieves 90 percent or greater SO, removal.
FMC's Soda Ash Plant
FMC Corporation operates a soda ash plant in Green River,
Wyoming. The plant has two coal-fired boilers (200-MW equivalent)
which burn coal containing 1.1 percent sulfur. Approximately 50
percent of the flue gases are scrubbed by the plant end-liquor in two
scrubbers, each with three pairs of disc-and-donut trays. A portion
of the recirculating liquor is continuously purged to remove sulfites
and sulfates formed by the reaction of SO, with soda ash. The
scrubber purge stream is discharged to a waste pond on site. A
mesh-type demister is used in each scrubber. Flue gases, reheated
by direct firing of natural gas at the exits of the scrubbers, are mixed
with bypassed gas and exhausted through the stack.
This system started up in May 1976 and reports 95 percent SO,
removal with an inlet loading of 800 ppm.
Dual Alkali Systems Demonstrate
Industrial Applicability
The dual alkali FGD process is similar to sodium-alkali
scrubbing in that it uses a sodium-based scrubbing liquor to absorb
SO, from flue gas. Dual alkali systems differ because they
regenerate the absorbent and produce a solid waste. Disposal
practices include treatment with fly ash and/or lime to fix the
sludge, which can then be used as landfill. Alternatively, untreated
sludge may be disposed of in well-designed, lined ponds.
Dual alkali systems are generally classified as "dilute" or
"concentrated," depending on the concentration of the active alkali
in the scrubbing liquor. Dilute dual alkali systems (see photograph
opposite) can handle scrubber oxidation rates of up to 100 percent
and produce solids containing hydrated calcium sulfate (gypsum).
Concentrated systems are only effective at scrubber oxidation rates
of up to 25 percent and yield a wasteproduct of hydrated calcium
sulflte or mixed crystals (hydrates of calcium sulflte and calcium
sulfate). Dilute dual alkali systems are often better suited to in-
dustrial installations where the boilers are fired with large amounts
of excess air, and oxidation in the scrubbers is less controlled.
The dual alkali process has become the second most popular
FGD method for industrial boilers. Five plants now use this method
of SO, control, with three of the absorbers operating in the dilute
mode. Construction of concentrated dual alkali FGD systems is
underway at two other plants.
Dual alkali FGD systems have demonstrated their suitability
for application to industrial boilers by their ability to handle high
rates of oxidation, prevent scale in the scrubber, and produce an
environmentally acceptable waste product.
Testing Completed at General Motors'
Parma Plant
EPA has been active in a program to evaluate a full-scale dilute
dual alkali system installed on four GM industrial boilers (32-MW of
equivalent electrical capacity). The GM test program was con-
ducted for EPA by GM and ADL at the Chevrolet Transmission
Plant in Parma, Ohio. Tests results collected from August 1974 to
May 1976 are evaluated in a report prepared by ADL (EPA-600/7-
77-005, see FGD Reports and Abstracts section).
The GM system at Parma consists of four scrubbers operating
in parallel. Each scrubber contains three bubble-cap absorption
trays and a mesh mist eliminator. The scrubbers handle a total of
3441 Nm'/min (128,400 scfm) of flue gas generated by the firing of
2.5 percent sulfur coal.
During the test program, total scrubber availability (time
operating/time required x 100) was 77,9 percent excluding four
long-term planned shutdowns for system modifications. Despite the
low SO, concentrations in the flue gas (800-1,300 ppm) caused by
high levels of excess air to the boilers, SOS removal was ap-
proximately 90 percent.
In addition to SO, removal, other parameters studied included
filter cake properties, solids dewatering, lime stolchiometry,
carbonate softening, soda ash stoichiometry, scaling in scrubber
loop, oxidation, entrainment, and reliability.
The system was in a constant state of development throughout
the test program and thus did not generally perform In accordance
with original design criteria. It dtd. however, show substantial
improvement over time. Further testing has been recommended to
demonstrate long term reliability.
Caterpillar Tractor Company's Dual Alkali
Systems
Other notable applications of the dual alkali process to in-
dustrial boilers include two at Caterpillar Tractor Company Plants.
The Mossville Plant near Peoria, Illinois, uses a concentrated dual
alkali process marketed by FMC Corporation. This unit is the
largest dual alkali system in the U.S. The plant has four boilers
(57-MW equivalent) firing 3.2 percent sulfur coal. Flue gas from
each boiler is in a separate scrubbing train. A key feature of the
Mossvilte installation is the simultaneous collection of fly ash and
SO, In dual-throat scrubbers. SO, removal ranges upward from 90
percent, and overall system availability has been 80-85 percent
since October 1975.
The Joliet Plant of Caterpillar Tractor Company operates two
boilers (18-MW equivalent) firing 3.2 percent sulfur coal. Emissions
are controlled by Zurn Industries' dilute dual alkali process. The
system has been operational since October 1974, with an average
scrubber availability of 80-85 percent. Removal of SO, has been 90
percent or higher.
Other FGD Processes Have Advantages
The magnesium oxide FGD process has potential for industrial
use, especially because it can regenerate scrubbing liquor from
multiple boiler FGD systems at one central location. However,
there are no major applications of this process to industrial boilers
in the U.S. at present.
Industrial use of lime/ limestone and citrate FGD systems in the
U.S. is limited. Each process, however, has advantages for in-
dustrial use.
The citrate process is being installed as a 50 MW-equivalent
system by St. Joe Minerals Corporation at Its G.F. Wheaton Power
Station. The station generates electricity for a zinc smelter. This is
the first commercial-size application of the citrate process. It will be
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FGD QUARTERLY REPORT/SPRING 1978
evaluated in a test program cofunded by St. Joe, U.S. Bureau of
Mines, and EPA. Startup is scheduled for September 1978. An
advantage of the citrate process is that, as with the magnesium
oxide process, scrubbing liquor from multiple boiler FGD systems
can be regenerated at one centra! location.
An example of a lime/limestone FGD installation is the A.8.
Bahco system operating at Rickenbacker Air Force Base in
Columbus, Ohio. The Bahco system was developed in Sweden and
is marketed in this country by Research Cottrell, Inc., under a
licensing agreement.
Under an Interagency Agreement with the Air Force, EPA
recently evaluated the Air Force's Bahco system. Comprehensive
tests, conducted over a period of 18 months, demonstrated that the
system is capable of controlling both particuiate and SO, emissions
from the combustion of high sulfur (2-4 percent) coal, with an SO,
removal efficiency of 90 percent. The final report is under review by
EPA and the Air Force and should be available later this year.
The Bahco system is a highly automated FGD process sold as
a package unit. It is offered in various standard sizes up to 50-MW
equivalent. An added feature of this process is that it is suitable for
installations where boiler loads vary significantly and turndown
capabilities are necessary. An automatic mechanism draws in
excess air when one of the boilers is shut down, thus maintaining a
constant volume of gas with varying concentrations of SO,.
The Future of FGD for Industrial Boilers
Two recent major developments are likely to accelerate the
application of FGD technology to industrial boilers:
* the President's National Energy Plan (NEP) which directs the
conversion from an oil- and natural gas-based energy system
to a coal based system, and
* EPA's program to develop New Source Performance
Standards (NSPS) to control emissions from industrial
boilers.
As part of the program to develop NSPS for industrial boiler
emissions, EPA is assessing the applicability of FGD to industrial
boilers. The study will examine the various typ«s of FGD systems,
their performance, and their energy, environmental, and economic
impacts.
Thus, as a result of increasing emphasis on conversion to coal
and the likelihood of stricter emissions codes, FGD systems are
expected to be more widely adopted by industry. A diversity of
proven FGD processes is now available to suit the varied operating
conditions and requirements of industrial boilers.
SODA ASH
LIME
MIX
TANK \ t
n f
MIX
TANK
«2
It
REACTOR
CLARIFIER
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SCRUBBER
THE GM DILUTE DUAL ALKALI SYSTEM.
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F6D QUARTERLY REPORT/SPRING 1978
IERL-RTP PILOT PLANT STUDIES
CONTINUE
Experiments at lERL-RTP's FGD pilot plant have investigated
sortie major problems associated with the lime/limestone FGD
process. Recent areas of investigation include {1) reducing fresh
water requirements of lime/ limestone systems, and (2) increasing
SO, removal efficiencies by using certain scrubber additives.
Water Requirements Can Be Reduced
The goal in reducing fresh water requirements is to maximize
water reuse and minimize discharge of soluble salts, either with
sludge or wastewater. This is possible by integrating new water
treatment processes (such as vapor-compression-evaporation) into
FGD systems using forced oxidation.
During January, tests at the IERL-RTP pilot plant were con-
ducted in a single-stage scrubber operating with forced oxidation.
Fresh water makeup was replaced with a sodium sulfate solution
simulating cooling tower blowdown liquid. (The cooling tower
blowdown is primarily a sodium sulfate solution which results as
water evaporates in the cooling tower, and sodium carbonate is
added for softening.) As a result of these tests, the following ob-
servations were made:
• No adverse effect of SO, removal efficiency was noted when
the scrubber was operated with 26,000 ppm Na* and 11,000
ppm Cl~ in the scrubbing liquor. Makeup consisted entirely
of a solution of Na.SO, (79g/l).
• Physical properties of the oxidized sludge, including settling
rate and Hlterability, were not adversely affected.
* No scaling occurred.
These experiments indicate that the substitution of boiler or
cooling tower blowdown for FGD fresh water makeup may be
feasible. However, pH control difficulties and unusually high levels
of gypsum supersaturation were noted and will require further in-
vestigation.
Additives Enhance SO2 Removal
Efficiency
Certain scrubber additives can increase SO, removal ef-
ficiency. Previous studies at the pilot plant have demonstrated thai
adipic acid is a suitable additive to scrubbers operating with forced
oxidation. Adipic acid is especially attractive because its ability to
enhance SO, removal is not affected by oxidation or by the ac-
cumulation of chlorides in the scrubbing loop.
Recent investigations of scrubber additives at the pilot plant
have examined magnesium oxide (MgO) as an alternative to the
more costly adipic acid. These tests used a double loop limestone
scrubber with forced oxidation carried out in the first loop. (The
double loop system separates the forced oxidation step from SO,
removal. This is necessary when using MgO because the ability of
MgO to enhance SO, removal is reduced by oxidation.)
Accumulation of chloride in the scrubbing loop also interferes
with the effectiveness of MgO. Chloride reacts with MgO to form
magnesium chloride (MgC!,). Thus, with increasing levels of
chloride, higher concentrations of MgO are required to enhance
SO, removal. The relationship is summarized below:
effective magnesium = total ppm Mg - GG_1—
2.92
where effective magnesium is the threshold concentration of MgO
which must be exceeded to obtain an improvement in SO, removal
efficiency. This relationship is discussed in detail in "EPA Alkali
Scrubbing Test Facility: Advanced Program (Third Progress
Report)" (EPA-600/7-77-105, see FGD Reports and Abstracts
section).
An SO, removal efficiency of 96 percent was obtained with an
effective magnesium level of 9,500 ppm. At 6,700 ppm effective
magnesium removal was 90 percent. This compares with only
70-80 percent removal at the same operating conditions without
magnesium.
In addition to increasing SO, removal efficiency, MgO addition
demonstrated high limestone utilization and yielded an oxidized
sludge which filtered to 80 percent solids. These promising results
will be evaluated further under similar conditions at EPA's 10-MW
Shawnee test facility.
Ongoing experiments at the IERL-RTP pilot plant are ex-
panding on the studies reported here. More information is available
from the IERL-RTP Project Officer, RobertH. Borgwardt (919) 541-
2234 or (FTS) 629-2234. See also the feature article in the last issue
of the FGD Quarterly Report (Volume 2, Number I).
WELLMAN LORD/ALLIED CHEMICAL
FGD DEMONSTRATION
Despite problems associated with boiler No. 11 at
Northern Indiana Public Service Company's (NIPSCO's) D.H.
Mitchell Station during the first 8Vz months of the demonstration
year, the plant and FGD system are presently completing a con-
tinuous month of successful operation. The FGD plant has been
down for 199 days (out of a possible 258 days thus far in the
demonstration year). Approximately 90 percent of this downtime
has been caused by problems associated with the boiler plant.
Personnel from EPA and NIPSCo met several times during the
past few months to discuss system operations. During the meetings
two external problems were identified which contributed
significantly to the boiler problems:
• High levels (5 ppb) of silica were present In the boiler feed
water and necessitated lower steam plant boiler loads in
order to prevent damage to the generator turbine blades.
• The only high-sulfur coal available during the recent strike
was contaminated with metal ores which caused
mechanical damage to the coal pulverizer mill, thus
reducing steam plant boiler loads.
The water purification system was previously unable to keep up
with water makeup requirements. These requirements have been
reduced by eliminating the unnecessary waste of condensate, and
the purification system is now able to reduce silica concentrations in
the boiler feedwater to acceptable levels,
Since the strike settlement the quality of available coal has
improved. NIPSCo tested the new coals during April and was able
to increase boiler output to acceptable levels. (The FGD plant
cannot operate below a certain boiler capacity, 46-MW, because
the volume of flue gas is insufficient to keep the scrubbing liquor on
the absorber trays.)
An additional problem which developed in the system was also
caused by a boiler difficulty. Flue gas temperatures at the mouth
of the boiler induced-draft fan were found to be about 110° C
<230°F), a deviation from design values of 150°C <300°F). The
lower temperature is below the dew point of sulfuric acid (H,SO,).
This caused acid condensation in the ductwork leading to th*1
absorber booster fan and on the fan blades themselves. The con-
densation on the fan blades resulted in corrosion and imbalance.
The damaged fan was repaired, tested, and reinstalled, and the
FGD system was able to resume full capacity integrated operation
in May. For additional information, contact the IERL-RTP Project
Officer, C.J. Chatlynne (919) 541-2915. (See also the fall and
spring issues of the FGD Quarterly Report for detailed summaries
of the first 4'A months of operating experience.)
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FGD QUARTERLY REPORT/SPRING 1978
STUDY EXAMINES FGD WATER
DEMANDS AND EFFLUENT STREAMS
A report prepared by Radian Corporation ("Controlling SO,
Emissions from Coal-Fired Steam-Electric Generators: Water
Pollution Impact", EPA-600/7-78-045a and b, see FGD Reports
and Abstracts section) defines and assesses the effects of alternative
sulfur removal technologies on the water consumption and
wastewaters from coat-fired power plants. The sulfur removal
technologies examined include five viable FGD processes (lime wet
scrubbing, limestone wet scrubbing, Wellman-Lord sulflte scrub-
bing, magnesium oxide slurry absorption, and dual alkali wet
scrubbing). The study also analyzes a physical coal cleaning
process which mechanically removes pyrite from coal.
The report presents the following conclusions:
• Added water demands imposed by SO, control increase
total plant makeup requirements by 8-11 percent, depending
on the process used.
• Adding a physical coal cleaning step raises the increase in
total plant water demand from 8 to 12 percent when the coal
cleaning is paired with lime or limestone scrubbing.
* Stricter NSPS standards have little effect on water demand.
* Requiring 90 percent sulfur removal generally has little effect
on water demand.
* Volume and quality of wastewater streams from SO,
control systems are affected very little by alternative NSPS
regulatory strategies.
* Proven commercially available technologies can be used to
treat all effluent streams to acceptable levels.
This study was one of several conducted to assist EPA's Office
of Air Quality Planning and Standards (OAQPS) in reviewing the
New Source Performance Standards (NSPS) for SO, emissions
from coal-fired steam generating units. The studies examine in
detail the impacts of the existing NSPS and of two alternative
revised standards.
Existing NSPS allow an emission rate of 0.52g SO,/MJ (1.2 Ib
SOj/10* Btu) of heat input. The alternative standards under
consideration are (1) an emission limit of 0.22g SOj/MJ (0.5 Ib
SO,/10* Btu) of heat input, and (2) a requirement of 90 percent
removal of SO, from stack gases, regardless of original sulfur
content of the coal. This latter alternative would require users of
both low and high sulfur coals to achieve a percent reduction:
however, the 90 percent removal could include elimination of SO,
by coal cleaning in addition to FGD.
Water requirements were calculated for model power plant
water systems and model SO, control systems which were provided
by EPA. Effluent streams from uncontrolled coal-fired power plants
and from each SO, removal process were also characterized. The
data were used to assess the impact on receiving waters.
The model systems used in this study permit an analysis of the
three alternative NSPS for SO, and accommodate several
variables, including the type of FGD process, sulfur content of the
coal, size of the steam generator (25-, 100-, 500-, and 1000-MW),
and degree of coal cleaning.
Further information regarding this study is available from the
IERL-RTP Project Officer, J. W. Jones, (919) 541-2489 or (FTS)
629-2489. (See also the FGD Reports and Abstracts section of this
issue.) Background information on EPA's review of SO, NSPS is
presented in the fall issue of the FGD Quarterly Report (Volume 1,
Number 3).
UPCOMING EVENTS IN FGD
Fifth FGD Symposium
The fifth FGD Symposium will be held March 4-8, 1979, at
Caesar's Palace in Las Vegas. The symposium will provide a forum
for the exchange of ideas and information on recent developments
in FGD systems and processes, as well as topics related to SO,
control.
Session topics and formats are now being planned. Comments
and suggestions are most welcome. This Is our chance to make the
Fifth FGD Symposium the best ever. Please contact C. J.
Chatlynne, either by telephone — (919) 541-2915 — or by letter,
with your thoughts and suggestions.
APCA Offers FGD Refresher Course
Michael C. Osborne of EPA/IERL- RTFs Emissions/Effluent
Technology Branch will present a refresher course entitled "Flue
Gas Desulfurization Waste Disposal Techniques". The course will
provide an overview of alternatives available for FGD waste
disposal. Current disposal practice in the power industry will be
discussed, along with novel disposal methods under Investigation
by EPA.
The course is part of a program which will be presented by the
Air Pollution Control Association (APCA) at their annual meeting
and exhibition in Houston, Texas. The course will be given from
3:00 to 5:00 p.m. on Sunday, June 25, 1978, at the Hyatt Regency
Hotel. For additional information, contact M. C. Osborne (919)
451-2483 or (FTS) 629-2483.
Symposium to Review Particulate Control
Technology
The First International Symposium on Transfer and Utilization
of Particulate Control Technology is slated for July 24-28, 1978, in
Denver, Colorado. The symposium is sponsored by EPA/IERL-
RTP's Particulate Technology Branch, Utilities and Industrial
Power Division.
This is the first EPA-sponsored conference on particulate
control to treat the various isolated technologies at a single sym-
posium. Major topics will be scrubbers, fabric filters, and elec-
trostatic precipitators. New concepts and technologies will also be
explored. Additional information can be obtained from Dennis C.
Drehmel, IERL/RTP, (919) 541-2925 or (FTS) 629-2925.
1977 FGD SYMPOSIUM PROCEEDINGS
The Fourth FGD Symposium (November 1977, Hollywood,
Florida) addressed full-scale FGD process applications in the U.S.,
Japan, and the Federal Republic of Germany. Laboratory, pilot,
and prototype research and development (R&D) efforts wert" also
presented. The Symposium provided an opportunity for the an-
nouncement of additional data and results which were previously
unreported or not widely publicized. The economics of FGD and the
disposal, use, and marketing of FGD system by-products were also
discussed.
The symposium papers were presented by a cross-section of
FGD users, government and private developers, and vendors. The
Proceedings (EPA-60Q/7-78 058a & b, see FGD Reports and
Abstracts section) contain copies of the participating authors'
papers and are being sent to all symposium registrants. As supplies
permit, additional copies are available free of charge and may be
obtained by contacting the Symposium Vice-Chairman, J. W.
Jones, 1ERL-RTP, (919) 541-2489 or (FTS) 629-2489.
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FGD QUARTERLY REPORT/SPRING 1978
FGD SLUDGE DISPOSAL STUDIES
The use of coal becomes increasingly important as available oil
and natural gas resources are depleted, and as production costs of
oil and gas increase. The President's proposed National Energy
Plan (NEP) will accelerate conversion to a coal-based energy
system. Under the proposed NEP, yearly consumption will be in-
creased by 200 Tg (200 million tons) by 1985.
The NEP requires that new coal burning plants be fitted with
FGD systems. Nonregenerable FGD systems (lime/limestone or
dual alkali scrubbing) are proven processes and can be expected to
proliferate in view of the increased emphasis of conversion to coal.
A major environmental problem, however, is disposal of wastes
produced by these systems.
No Federal criteria exist for disposal of FGD sludges. However,
the Resource Conservation and Recovery Act of 1976 (RCRA)
requires EPA to establish regulations for the disposal of hazardous
wastes and to work with the states in developing adequate disposal
plans for non-hazardous solid wastes. Hazardous waste disposal
regulations and guidelines for state plans are expected to be
promulgated In 1978. Some FGD sludges may ultimately fall in the
hazardous waste category, although no definite determination has
been made. At EPA, IERL-RTP is working with the Office of Solid
Waste (OSW) to address this current uncertainty.
Wide variations exist in disposal methods, and sludge and site
characteristics. EPA is conducting several studies to define and
evaluate environmentally sound disposal methods. Several of these
studies are briefly described below. See also the fall issue of the
FGD Quarterly Report {Vol. 1. No. 3). This research is providing
EPA with a basis for developing effective FGD sludge disposal
criteria.
FGD Sludge Conversion Studies
Pullman Kellog of Houston, Texas, has successfully completed
sludge reduction tests (using coal) in a 61 cm (24 in.) diameter, 9 m
(30 ft) long rotary pilot kiln. Subsequent bench-scale carbonation
tests of the reduced sludge (mostly CaS) resulted in over 99 percent
conversion of the CaS and CaO to CaCOj. In addition, bench-scale
flotation/separation tests demonstrated a recovery of over 80
percent CaCOj from the CaCOj/ash mixture. These tests were the
base for further pilot tests of the carbonation and recovery steps.
Results have also confirmed the technical viability of the conversion
process. More information is available from the IERL-RTP Project
Officer, J.W. Jones (919) 541-2489 or (FTS) 629-2489.
Economic Studies
The Tennessee Valley Authority (TVA) has recently completed
Phase II of an economic study of FGD sludge disposal alternatives.
The results of this study indicate that landfill of gypsum (CaSO, « 2
H,O) is the least expensive of all disposal alternatives considered
thus far, including untreated sludge ponding. In addition, the an-
nual revenue requirements (annual operating costs and annualized
capital costs) of a gypsum-producing FGD system are less than
those for most other processes, despite the requirements for forced
oxidation equipment. (Annual revenue requirements for an FGD
system which includes untreated sludge ponding are about 5
percent lower than those of a system which disposes of gypsum in a
landfill.)
IERL-RTP has demonstrated the technical viability of gypsum-
producing FGD systems through numerous tests on a small pilot
plant at RTP and two large (10-MW) pilot plants at TVA's Widow's
Creek steam plant. Additional information on TVA's economic
studies concerning gypsum marketing and sludge disposal is
available from the IERL-RTP Project Officer, J. W. Jones (919)
541-2489 or (FTS) 629-2489. For more information regarding the
development of gypsum-producing FGD, contact the IERL-RTP
Project Officer, J.E. Williams (919) 541-2483 or (FTS) 629-2483.
Physical and Chemical Properties of FGD
Sludges
A study conducted by TVA under an Interagency Agreement
with EPA features a long term characterization of lime and
limestone scrubbing sludges. Previous work had involved extensive
physical and chemical analyses of sludges produced by FGD
processes. However, such work was usually of short duration and
did not address the total range of solids' variability or relate any of
the characteristics to scrubber operating conditions. Since the
chemical and physical composition of sludges determines handling
and disposal requirements, additional research in solids charac-
terization is essential.
The TVA study provides some of the needed information
regarding long term solids' analysis. Samples from the Shawnee
Test Facility were examined to compare sludge properties (such as
settling rate, final bulk density, and solids content) to process
operating conditions (including hold tank residence time, system
stoichiometry, and presence of fly ash). Optimum conditions of
crystal growth were also investigated because of their effects on
dewatering, filtration rates, and liquid entrainment.
EPA and TVA are now reviewing the final report. Additional
information is available from the IERL-RTP Project Officer, M.C.
Osborne (919) 541-2898 or (FTS) 629-2898.
Stabilizing Additives for FGD Sludges
A TVA report presents comprehensive petrographic,
mincralographic, and chemical characterizations of fluidized-bed
combustion (FBC) materials. Of relevance to FGD arc disposal
studies which examine the use of FBC materials as stabilizing
additives for FGD sludges. These studies consider both the particle
size distribution in the FBC materials and the chemical com-
position as a function of size fraction.
FBC samples were obtained from the Argonrw National
Laboratory, the Combustion Power Company, and the Exxon
Research and Engineering Company. Experiments used com-
parative optical and electron microscopy. X-ray diffraction, infrared
specrrometry, and electron microprob* analyses to study the
composition and morphology of the FBC samples.
The TVA report was prepared under an Interagency Agreement
with EPA. The final draft is being reviewed by EPA and TVA. For
further information contact the iERL-RTP Project Officer, M.C.
Osborne (919) 541-2898 or (FTS) 629-2898.
FGD Gympsum Marketing Study
TVA has submitted the draft final report of a study concerning
the marketing of FGD gypsum for use in the manufacture of
wallboard and portland cement. The current annual consumption of
gypsum for wallboard and portland cement is about 14.5 Tg (16
million tons); approximately 75 percent of this consumption is for
wallboard. Current projections for FGD sludge production in the
mid-1980's is about 27.2 Tg (30 million tons) annually.
The TVA report presents two significant conclusions:
* In a competitive market, two-thirds of the natural gypsum
used in the portland cement Industry could be replaced by
FGD gypsum. This could account for a 74 percent reduction
in the requirements for imported gypsum.
• The market for FGD gypsum in wallboard manufacture does
not appear promising. However, the study was based on the
current structure of the wallboard market. A major feature of
this structure is the location of wallboard plants near the
source of gypsum. The picture would be quite different if
wallboard plants were located at the power plants or near
the points of wallboard use.
Further information is available from the IERL-RTP Project
Officer, J.W. Jones (919) 451-2489 or (FTS) 629-2489.
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FGD QUARTERLY REPORT/SPRING 1978
Shawnee Field Studies Assess FGD Sludge
Disposal
EPA has renewed a contract with the Aerospace Corporation
to continue and expand an ongoing study of the disposal of sludges
from lime and limestone scrubbers. This project started 4 years ago
and is the most extensive long term analysis of disposal sites to
date.
All waste material used in the project is generated from
prototype scrubbers at TVA's Shawnee Steam Electric Plant.
Wastes are placed in nearby disposal sites. The new study will in-
clude the eight ponds now under evaluation, as well as up to three
additional ponds to be constructed during the contract period.
Tests will be performed to determine the quality of water from
all wells and underdrain systems. Additional experiments will
examine the quality of the chemically treated or conditioned
sludges with respect to strength, permeability, and leaching effects.
Results of all test data will be related to potential water quality
and solid waste disposal criteria. The study will also estimate
engineering costs of the disposal processes. Further information is
available from the IERL-RTP Project Officer, M.C. Osborne (919)
541-2898 or (FTS) 629-2898.
FGC Sludge Disposal Data Base
A study has been completed which establishes a data base for
future development of standards for the disposal of flue gas cleaning
(FGC) sludges. FGC sludges usually contain, in addition to wastes
generated by FGD, additional materials such as fly ash. The data
base reflects the present state of knowledge on the disposal and
environmental impact of FGC sludges. SCS Engineers, Long
Beach, California, conducted the study under contract to
EPA/MERL-Cinn.
The first phase of the project developed background in-
formation and established criteria necessary to evaluate the options
available for FGC sludge disposal. The second phase developed an
information base for future standards development. The data base
includes, in addition to the technical bases, interrelationships
between environmental effects and regulatory approaches.
The final report, entitled "Data Base for Stan-
dards/Regulations Development for Land Disposal of Flue Gas
Cleaning Sludges," has been released (EPA 600/7-77-118, see
FGD Reports and Abstracts section). Additional information may
be obtained from the EPA/MERL-Cinn Project Officer, D.E.
Sannlng (513) 684-7871 or (FTS) 684-7871,
FILMS EXPLAIN WELLMAN-LORD AND MAGNESIUM OXIDE FGD PROCESSES
Two films covering FGD processes and intended primarily for
audiences unfamiliar with FGD technology have been made
available by EPA. "The Wellman-Lord/Allied Chemical Flue Gas
Desulfurization Process" (EPA No. TF 125) is a 13'/2 minute film
about the Wellman-Lord/Allied Chemical FGD Demonstration
Program.
"Magnesium Oxide" (EPA No. TF 126) covers the Boston
Edison and PEPCo magnesium oxide (MgO) scrubbing programs.
These demonstration programs were jointly sponsored by EPA and
the host utilities to assess the feasibility of the MgO FGD process.
The film is 11 minutes long.
Video tape copies of these two FGD process films will be shown
at the June APCA meeting in Houston, Texas (see Upcoming
Events in FGD).
Both 16mm films are available in color and sound, on free
loan, from:
RHR Filmedia
Distribution Section
1212 Avenue of the Americas
New York, NY 10036
Requests for copies should specify film title and EPA number.
LIMESTONE FGD PLANT MEETS
EMISSION REGULATIONS
Performance testing was recently completed on the limestone
FGD system installed at Unit 1 of the City of Springfield, Missouri,
Southwest Power Plant. The boiler burns 3.5 percent sulfur coal and
has a generating capacity of 194-MW.
A turbulent contacting absorber uses the wet limestone
scrubbing process to remove SO, from the flue gas. Flue gas from
the boiler electrostatic precipitator (ESP) enters the scrubber at the
presaturator. The gas flows countercurrent to the limestone slurry
through the three absorbing layers. The flue gas is demisted in a
two-stage chevron demister and exhausted through a 117 m
(384 ft) stack.
Compliance testing was conducted by Burns and McDonnell
Engineering Company of Kansas City, Missouri. The objective was
to determine compliance with federal and state emissions
regulations. These current regulations limit particulate emissions to
0.43 g/MJ(0.1 lb/10*Btu)of heat input, SO, emissions to
0.52 g/MJ (1.2 Ib/10«Btu) and NOX emissions to 0.303 g/MJ (0.7
lb/10'Btu).
Test results showed compliance with the regulations. Par-
ticulate emissions averaged 0.008g/MJ (0.018 lb/10* Btu).-average
SO, emissions wereO.228 g/MJ (0.526 lb/10* Btu);and NOX
emissions were 0.291 g/MJ (0.672 lb/10' Btu). These relatively low
emissions values resulted from overdesign of the FGD system to
ensure compliance with continued use.
The SO, removal system achieved an average removal ef-
ficiency of 91.7 percent.
REPORTS DESCRIBE UTILITY FGD
SYSTEMS
Five survey reports on individual utility FGD systems have been
prepared for EPA by PEDCo Environmental, Inc. The reports (EPA-
600/7-78-048a, b, c, d, and e; see FGD Reports and Abstracts
section) describe FGD installations at the following utilities:
• Arizona Public Service Company, Cholla Station;
• Commonwealth Edison Company, Will County Station;
• Detroit Edison Company, St. Clair Station;
* Kansas City Power and Light Company, La Cygne Station;
and
• Kentucky Utilities, Green River Station.
The FGD system at Kentucky Utilities employs lime scrubbing,
while limestone scrubbing is used at the other plants.
The reports, completed after site visits to the respective plants,
give more detail than the bimonthly EPA Utility FGD Survey. Each
report contains facility and FGD system description (including
process chemistry and process control). FGD system performance
is assessed, with emphasis on background information, operation
history, start-up and operation (problems and solutions), and
economics.
For additional information, contact the IERL-RTP Project
Officer, N. Kaplan (919) 541-2556 or (FTS) 629-2556.
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FGD QUARTERLY REPORT/SPRING 1978
FGD REPORTS AND ABSTRACTS
This section of the FGD Quarterly Report contains abstracts of
recently completed reports relating to flue gas desulfurization. Each
listing includes date of the report. National Technical Information
Service (NTIS) accession number, and other identifying numbers
when available.
Each report with an NTIS number can be ordered from NTIS.
The cost of paper copies varies by page count ($4.00 minimum);
microfiche copies are $3. Payment must accompany order. The
address is: National Technical Information Service
U. S. Department of Commerce
Springfield. Virginia 22161
EPA/IERL-RTP reports which do not have an NTJS number
are available, as supplies permit, through IERL-RTP*s Technical
Information Service (T1S). The address is:
W. W. Whelan, MD-64
Technical Information Service
Industrial Environmental Research Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
(919)541-2216
(FTS) 629-2216
EPA Industrial Boiler FGD Survey: First Quarter
1978
J. Tuttle, A. Patkar, and N. Gregory, PEDCo Environmental, Inc.,
Cincinnati, Ohio, March 1978. EPA-600/7-78-052a. PB 279 214.
EPA Project Officer: J.D. Mobley, IERL-RTP.
The report presents detailed technical information concerning
application of flue gas desulfurization (FGD) systems to industrial
boilers. The information was obtained by a survey of plant per-
sonnel, control system vendors, regulatory agencies, and consulting
engineering firms. The data is 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 techniques, operation status, start-up date,
and flue gas capacity. Detailed information includes: control system
design, economics, operating experience, problems and solutions,
waste disposal techniques, and maintenance practices.
Evaluation of the General Motors' Double Alkali
SOf Control System
E. Interess, Arthur D. Little, Inc., Cambridge, Massachusetts,
January 1977. EPA-600/7-77-005. PB 263 469. EPA Project Of-
ficer: N. Kaplan, IERL-RTP.
The report is an evaluation of the double alkali flue gas
desulfurization (FGD) system, installed to control SO, emissions
from the coal-fired industrial boiler complex at General Motors'
Chevrolet plant in Parma, Ohio. It describes the boiler and FGD
systems. It addresses performance with respect to SO, removal,
filter cake properties, lime stoichiometry, carbonate softening, soda
ash stoichiometry, scaling, oxidation, and reliability. The
evaluation is presented in terms of three 1-month-long intensive test
periods and a longer-term non-intensive test period. System
material balances are presented for some of these periods. A
general history of the operation is also presented.
Proceedings: Symposium on Flue Gas
Desulfurization — Hollywood, FL, November 1977.
Volume I.
F. A. Ayer, Compiler, Research Triangle Institute, Research
Triangle Park, North Carolina, March 1978. EPA-600/7-78-058a
EPA Project Officer: J.W. Jones, IERL-RTP.
The proceedings document presentations made during the sym-
posium, which dealt with the status of flue gas desulfurization
technology in the United States and abroad. Subjects considered
included: regenerable, non-regenerable, and advanced processes:
process costs: and by-product disposal, utilization, and marketing.
The purpose of the symposium was to provide developers, vendors,
users, and those concerned with regulatory guidelines with a
current review of progress made in applying processes for the
reduction of sulfur dioxide emissions at the full- and semi-
commercial scale.
Proceedings: Symposium on Flue Gas
Desulfurization — Hollywood, FL, November 1977.
Volume II.
F. A. Ayer, Compiler, Research Triangle Institute, Research
Triangle Park, North Carolina, March 1978. EPA-600/7-78-058b.
EPA Project Officer: J.W. Jones, IERL-RTP.
See EPA-600/7-78-058a for abstract.
Controlling SO» Emissions from Coal-Fired Steam-
Electric Generators: Water Pollution Impact.
Volume I. Executive Summary. Volume II.
Technical Discussion.
R.L. Sugarek and T.G. Sipes, Radian Corporation, Austin, Texas,
March 1978. EPA-600/7-78-045a & b. PB 279 635 & 6. EPA
Project Officer: J.W. Jones, IERL-RTP.
The report gives results of one task in a comprehensive program to
review the New Source Performance Standards (NSPS) for SOf
emissions from coal-fired steam-electric generating plants. The
results compare two alternative standards to the existing NSPS (1.2
IbSOj/millionBtuof heat input): (1)0.5 Ib SO,,''million Btu of heat
input, allowing credit (as does the existing NSPS) for physical coal
cleaning or use of low sulfur coal; and (2) 90% removal of SO, from
stack gases, regardless of original coal sulfur content. The com-
parisons are in terms of their effect on the quality and quantity of
power plant uiastewater effluents and on the amount of plant water
consumption. Potential effects of SO, control system effluents on
the environment are evaluated, and alternative treatment processes
are discussed. A total of 108 plant systems were discussed, in-
cluding combinations of three NSPS, five flue gas desulfurization
(FGD) systems, five coal types, four plant sizes, and sulfur removal
by coal cleaning. Volumes and quality of wastewater streams varied
very little from one alternative NSPS to another; all streams can be
treated adequately using commercially available technologies.
However, the alternative standards increase total water con-
sumption 8-11%, depending on the FGD process used. Physical
cleaning plus lime/limestone scrubbing increases total water
consumed 8-12%.
8
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FGD QUARTERLY REPORT/SPRING 1978
Effective Control of Secondary Water Pollution from
Flue Gas Desulfurization Systems
L. D. Weinier, Resources Conservation Company, Renton,
Washington, September 1977. EPA-600/7-77-106. PB 278373.
EPA Project Officer: M.C. Osborne, IERL-RTP.
The report describes tests to demonstrate the feasibility of using a
vertical-tube, falling-film, vapor-compression evaporator to con-
centrate waste water from a flue gas desulfurization (FGD) process.
Tests showed that waste water from the Chiyoda FGD process can
be concentrated up to 140 times and with recovery of more than 99
percent of the waste stream as high quality water (< 10 ppm TDS).
Two series of tests were conducted: one with a 25 gpd bench model
evaporator; the other with a 6,000 gpd pilot size evaporator.
Process conditions were identified and verified for scale free
operation. Heat transfer coefficients of 500-750 Btu/hr-sq ft-°F
were consistently achieved throughout the tests. A conceptual
design and economic study of a full size treatment facility showed
that capital costs will range from $5,110 to $8.706/1,000 gpd of
waste water processed, depending on system capacity. Operating
costs will vary from $2.46 to $3.60/1,000 gallons of waste water
processed, depending on system capacity and waste water com-
position. Some credit can be taken for savings on boiler makeup
water treatment costs by providing the high quality distillate to that
process.
Process Synthesis and Innovation in Flue Gas
Desulfurization
G.T. Rochelle, Electric Power Research Institute, Palo Alto,
California, July 1977. EPRI-FP-463-SR. PC A14/MF A01.
Process synthesis and Innovation have been effected and evaluated
for processes that desulfurize stack gases by aqueous scrubbing
with disposal of CaSOs/CaSO« or solution regeneration by H,S or
steam. Novel applications have been identified for buffering ad-
ditives such as sulfopropionic, oxalic, and adipic acids and for
alkali additives such as MgO, NH,, Na,CO,, and ethylenediamine.
One of the important novel flowsheet configurations identified in
each area was: throwaway slurry scrubbing with intentional
oxidation in the scrubber loop and buffer additives; H.S
regeneration with recycle of solution which is partially regenerated
to eliminate bisulfite; and steam stripping of a slurry of buffer acid
or pyrosulfite with reboiler evaporation and with water condensate
returned to the top of the stripper. Systematic structuring of the
available process alternatives encouraged the definition of novel
processes by technology transfer and the invention of new
subalternatives. Evolutionary evaluation of the process alternatives
was substantially hindered by interactions between subsets of
alternatives.
EPA Alkali Scrubbing Test Facility: Advanced
Program (Third Progress Report).
H. N. Head, Bechtel Corporation, San Francisco, California,
September 1977, EPA-600/7-77-105. PB 274 544. EPA Project
Officer: J.E. Williams, 1ERL-RTP.
This is the third progress report on an Advanced Test Program
under the direction of EPA to test prototype lime and limestone wet-
scrubbing systems for removing SO, and particulate matter from
coal-fired boiler flue gases. It covers the period from mid-February
1976 through November 1976. Results of earlier testing are
reported in EPA-650/2-75-047, EPA-600/2-75-050, and EPA-
600/7-76-008. The program is being conducted at a test facility
operating on flue gas from Boiler No. 10 at TVA's Shawnee Power
Station, Paducah, Kentucky. Bechtel Corporation is the major
contractor and test director, and TVA is the constructor and facility
operator.
Data Base for Standards/Regulations Development
for Land Disposal of Flue Gas Cleaning Sludges
D. E. Weaver, C. J. Schmidt, and J. P. Woodward. SCS
Engineers, Long Beach, California, December 1977. EPA-600/7-
77-118. EPA Project Officer: D.E. Sanning, MERL-Clim,
The study addresses the problem of flue gas cleaning (FGC) sludge
disposal to the land. It considers the problem from a potential
regulatory approach, looking at the various aspects which could
play a part in determining the best practical control technology
currently available. Factors considered Include: (1) the origin of the
FGC sludge problem (character of the fuel, combustion process,
gas cleaning, and sludge management); (2) criteria for the
evaluation of sludge disposal options (sludge characteristics,
health, ecological, safety, and aesthetic considerations); (3) ap-
plicable, existing, or proposed standards/regulations (solid waste,
hazardous waste, drinking water, and air pollution regulations);
and (4) impacts of applying existing standards/regulations to the
disposal of FGC sludges (cost aspects). The report presents 14
conclusions supporting the need for FGC sludge disposal
regulations and suggests a decision tree approach to the for-
mulation of guidelines and limitations for FGC sludge management
which takes into account site specific geographical and
hydrological considerations. The report contains 179 references
and an Appendix on The Equations of Mass Transport.
Electric Utilities' Use of Flue Gas Desulfurization
Technology in the United States
A.Q. Dasti, Federal Energy Regulatory Commission, Washington,
D.C., October 1977. PB 274 120.
This is an updated report on units which remove sulfur compounds
from stack gases of coal-burning electric power generating plants.
The earlier comprehensive report, "The Status of Flue Gas
Desulfurization Applications in the United States," was issued in
July 1977 by the former Federal Power Commission.
Evaluation of Three 20-MW Prototype Flue Gas
Desulfurization Processes
R. E. Rush and R. A. Edwards, Southern Company Services, Inc.,
Birmingham Alabama, March 1978. 3 Vols. EPRI-FP-713-SY.
The two 40-MW (nominal) Babcock & Wilcox pulverized-coal-flred
boilers at the Scholz Electric Generating Station of Gulf Power
Company were retrofitted with three 20-MW prototype flue gas
desulfurization systems. The systems used included:
• A concentrated-mode, lime-regeneration sodium/calcium
dual alkali process supplied by Combustion Equipment
Associates, Inc./Arthur D. Little, Inc.
• The Chiyoda Thoroughbred (CT-101) process supplied by
Chiyoda International Corporation, a subsidiary of Chiyoda
Chemical Engineering and Construction Company, Ltd.
• The Foster Wheeler Energy Corporation/Bergbau-
Forschung GmbH dry adsorption process supplied by Foster
Wheeler Energy Corporation.
The report summarizes the performance of these systems during an
evaluation that was conducted during 1975 and 1976.
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FGD QUARTERLY REPORT/SPRING 1978
Survey of Flue Cas Desulfurization Systems: Cholia
Station, Arizona Public Service Company
B.A. Laseke, Jr., PEDCo Environmental, Inc., Cincinnati, Ohio,
March 1978. EPA-600/7-78-048a. PB 281 104. EPA Project Of-
ficer: N. Kaplan, 1ERL-RTP.
The report gives results of a second survey of the flue gas
desulfurization (FGD) system on Unit 1 of Arizona Public Service
Co.'s Cholia Station. The FGD system, commercially available in
December 1973, utilizes a limestone slurry in two parallel scrubbing
modules to control SO, and fly ash from the combustion of low
sulfur western coal. (The two-module FGD system is described.)
The system's total SO, removal efficiency is 58.5% (92% for the
SO, removal module). Either or both modules can be bypassed.
The flue gas cleaning wastes are disposed of in an on-site unlined fly
ash pond. No water is recycled from the pond to the FGD system.
Following a number of modifications of the FGD system by the
system supplier and the utility, the system has exhibited a high
degree of mechanical reliability while meeting required SO, and
paniculate emission control levels.
trains. Each train included a radial-flow venturi scrubber and a
high-velocity coyntercurrent spray tower absorber to control fly ash
and SOj. Flue gas cleaning wastes were discharged from a reaction
tank to an on-site claw-lined settling pond. Clear water was recycled
from the pond to the FGD system for further use. The FGD system
was designed to remove SO, and % ash from high sulfur eastern
coal. Actual operation was on low sulfur western coal. Following
the demonstration, the FGD system was shut down and modified
for resumption of paniculate scrubbing on low sulfur western coal in
the fall of 1977. Some SO, is removed from the flue gas during
particulate removal because of the alkalinity of the collected fly ash
and the limestone additive used for pH control of the scrubbing
solution.
Survey of Flue Gas Desulfurization Systems: La
Cygne Station, Kansas City Power and Light
Company
B.A. Laseke, Jr., PEDCo Environmental, Inc., Cincinnati, Ohio,
March 1978. EPA-600/7-78-048d. PB 281 107. EPA Project Of-
ficer: N. Kaplan. 1ERL-RTP.
Survey of Flue Gas Desulfurization Systems: Will
County Station, Commonwealth Edison Company
B.A. Laseke, Jr., PEDCo Environmental, Inc., Cincinnati, Ohio,
March 1978. EPA-600/7-78-048b. PB 281 105. EPA Project Of-
ficer: N. Kaplan, 1ERL-RTP.
The report gives results of a second survey of the flue gas
desulfurization (FGD) system on Unit 1 of Commonwealth Edison
Co.'s Will County Station. The FGD system, started up in February
1972, utilizes a limestone slurry in two parallel scrubbing trains.
Each train includes a venturi scrubber, sump, and two-stage sieve
tray absorber for the control of fly ash and SO,. The flue gas
cleaning wastes are stabilized with lime and collected fly ash and
hauled away to an off-site disposal area. The FGD system operated
as an SO,-removal unit from February 1972 to July 1977, treating
flue gas from the combustion of low sulfur western coal, high sulfur
Illinois coal, and blends of both. Experimental SO,-removal
operations were concluded in July 1977. The scrubbing system
remains in service removing fly ash from low sulfur western coal flue
gas. Some SO, is removed from the flue gas during particulate-
removal operations because of the alkalinity of the collected fly ash
and the limestone additive used for pH control of the scrubbing
solution.
Survey of Flue Gas Desulfurization Systems: St.
Clair Station, Detroit Edison Company
B.A. Laseke, Jr., PEDCo Environmental, Inc., Cincinnati, Ohio,
March 1978. EPA-600/7-78-048c. PB 281 106. EPA Project Of-
ficer: N. Kaplan, IERL-RTP.
The report gives results of a survey of the flue gas desulfurization
(FGD) system retrofitted on Unit 6 of Detroit Edison Co.'s St. Clair
Station. The experimental FGD system, which operated through a
2-month (October 1976-January 1977) demonstration program,
utilized a limestone slurry to remove SO, in two parallel scrubbing
The report gives results of a second survey of the flue gas
desulfurization (FGD) system on Unit 1 of Kansas City Power and
Light Co.'s La Cygne Station. The FGD system, first started up in
February 1973 and commercially available in June 1973, utilizes a
limestone slurry in eight scrubbing modules to control fly ash and
SO, from the combustion of high sulfur subbituminous coal. Each
module includes a venturi scrubber, sump, and two-stage sieve tray
absorber. All the flue gas is treated; it cannot bypass the scrubbing
modules. Facilities for limestone grinding and storage and final
disposal of the flue gas cleaning wastes are on the plant grounds.
Clear water is recycled from the pond to the FGD system for ad-
ditional use. SOj and particulate removal efficiency measurements
indicate that the design values of 80 and 98.75%, respectively,
have been met or exceeded.
Survey of Flue Gas Desulfurization Systems: Green
River Station, Kentucky Utilities
B.A. Laseke, Jr., PEDCo Environmental, Inc., Cincinnati, Ohio,
March 1978. EPA-600/7-78-048e. PB 279 543. EPA Project Of-
ficer: N. Kaplan, IERL-RTP.
The report gives results of a survey of the flue gas desulfurization
(FGD) system retrofitted to Boilers 1, 2, and 3 at the Green Kiver
Station of Kentucky Utilities. The FGD system consists of one wet
lime scrubber module designed to handle a maximum of 170 cu
m/sec (360,000 acfm) of flue gas at 149°C (300°F), The scrubber
module contains a variable-throat venturi with a flooded elbow for
fly ash removal and a mobile-bed contactor for SO, removal. Th«>
flue gas cleaning wastes are discharged from the reaction tank to an
on-site clay-lined settling pond. Clear water is recycled from the
pond to the system for further use. The system was started up in
September 1975 and was certified commercial in January 1976.
Ensuing FGD operations revealed a number of major problems
which required the utility and the system supplier to repair and
replace the scrubber stack shell and liner, install a steam tube air
injection reheat system, and modify (and possibly replace) the
system's mist eliminator. The FGD system was in service 6046
hours in 1976 and 1964 hours in 1977 (November).
10
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FGD QUARTERLY REPORT/SPRING 1978
EPA PROJECT OFFICERS FOR CURRENT FGD RD&D PROJECTS
Robert H. Borgwardt, MD-65
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2234
(FTS) 629-2234
Ted G. Brna, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2683
(FTS) 629-2683
C. J. Chatlynne, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS) 629-2915
Julian W. Jones, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone:(919)541-2489
(FTS) 629-2489
Norman Kaplan, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2556
(FTS) 629-2556
Robert E. Landreth
USEPA, MERL-Cinn
26 West St. Claire St.
Cincinnati, OH 45268
Phone: (513)684-7871
(FTS) 684-7871
R. Michael McAdams, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone:(919)541-2915
(FTS) 629-2915
J. David Mobley, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS) 629-2915
Michael C. Osborne, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone:(919)541-2898
(FTS) 629-2898
Warren D. Peters, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone:(919}541-2915
(FTS) 629-2915
Wade H. Ponder, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)541-2915
(FTS) 629-2915
Michael H. Roulier
USEPA, MERL-Cinn
26 West St. Claire St.
Cincinnati, OH 45268
Phone: (513)684-7871
(FTS) 684-7871
Donald E. Sanning
USEPA, MERL-Cinn
26 West St. Claire St.
Cincinnati, OH 45268
Phone: (513)684-7871
(FTS) 684-7871
John E. Williams, MD-61
USEPA, IERL-RTP
Research Triangle Park, NC 27711
Phone: (919)451-2483
(FTS) 629-2483
The FGD Quarterly Report is prepared by Radian Corporation under EPA Contract No. 68-02-2608. The EPA Project Officer is R. Michael
McAdams (address above). The Radian Project Director is Charles E. Hudak, P. O. Box 9948, Austin, Texas 78766. (512) 454-4797. The Radian
Task Director for preparation of this issue is Elizabeth D. Gibson. Comments on this issue, suggested topics for inclusion in future issues, and
requests for subscriptions should be addressed to them.
The views expressed in the FGD Quarterly Report do not necessarily reflect the views and policies of the Environmental Protection Agency.
Mention of trade names or commercial products does not constitute an endorsement or recommendation for use by EPA.
11
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ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, N. C. 27711
Attention: R.M. McAdams (MD-61)
OFFICIAL BUSINESS
Penalty For Private Use $300
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Environmental Protection Agency
EPA - 335
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