TVA
Tennessee
Valley
Authority
Emission Control Development Projects
Division of Chemical Development
Muscle Shoals, Alabama
EPRI
Electric Power
Research
Institute
Air Quality Group
Palo Alto, California
EPA
United States
Environmental
Protection Agency
Office of Environmental Engineering & Technology ERA-600/9-79-043
Office of Research and Development November 1979
Washington, D.C. 20460
Decision Series
sulfur
apan
.; . . - '^^B
-------
energy/environment
R&D decision series
This volume is part of the Energy/Environment
R&D Decision Series. The series presents the key
issues and findings of the Interagency
Energy/Environment Research and Development
Program in a format conducive to efficient
information transfer.
The Interagency Program, planned and
coordinated by the Environmental Protection
Agency (EPA), was inaugurated in the fiscal year
1975. Research projects supported by the program
range from the analysis of health and
environmental effects of energy systems to the
development of environmental control
technologies.
The Decision Series is produced for both
energy/environment decision-makers and the
interested public. If you have any comments or
questions, please write to Editor, Office of
Environmental Engineering and Technology,
RD-681, U.S. EPA, Washington, D.C. 20460, or call
(202) 755-0324. Extra copies are available on
request. This document is also available to the
public through the National Technical Information
Service, Springfield, Virginia 22161. Mention of
trade names or commercial products herein does
not constitute EPA endorsement or
recommendation for use.
credits
EDITOR; Francine Sakin Jacoff
TEXT Charles R. Beek
EDITORS: BetteRohse
TEXT & Michael A. Maxwell, Industrial
TECHNICAL Environmental Research
REVIEW: Laboratory, RTP, ORD, EPA
H. William Elder, Chemical
Development Division, TVA
Thomas M. Morasky, Air Quality
Group, Electric Power Research
Institute
DESIGN: James M. O'Leary
GRAPHIC Aija I. Klebers
PRODUCTION: Stuart Armstrong
Jill L. Redden
Carolyn C. Steele
-------
^ * sulfur
oxides
control in
Japan
INTERAGENCY ENERGY/ENVIRONMENT RESEARCH AND DEVELOPMENT PROGRAM
-------
J
'**'
-------
overview: FGD in Japan
Because of major air and water pollution problems
in Japan during the 1960's economic boom, the
central government established the most stringent
sulfur dioxide (SOa) emission and ambient air
standards in the world. Such controls were
considered necessary because high levels of sulfur
pollution can be potential health and
environmental hazards. For example, inhaling
sulfur dioxide can cause irritation of the respiratory
tract; aggravating asthma and emphysema.
Significant reduction in air visibility can result from
sulfur pollution. Acid rain, another result of SO2
emissions, has been shown to reduce agricultural
and forest productivity, deplete soil nutrients,
cause failure of fish spawning, and corrode
building materials.
Sulfur oxides are generated from the burning of
fossil fuels. In Japan the major source of SO2
pollution is from the burning of heavy fuel oil by
the electric power generating plants. The primary
methods currently being practiced to control this
pollution are flue gas desulfurization (FGD) and
burning low sulfur fuels. During the past decade,
significant progress has been made in installing
FGD systems to control SO2 pollution. The
effectiveness in improving air quality in Japan and
the reliability of these systems have been
outstanding.
To evaluate these advances for their potential
application in the U. S., the Honorable Henry M.
Jackson, Chairman of the Senate Committee on
Energy and Natural Resources reo^iested the
Environmental Protection Agency to organize an
industry/government task force to visit Japan to
obtain first hand information on their experience
with FGD systems.
The task force members' observations during
that trip, their prior knowledge, and information
gathered from referenced sources comprise this
report. The first section provides an overview of
the:
• Japanese energy status,
• SO2 pollution emissions control regulations,
• The general status of FGD applications in the
industrial and utility sectors,
• Comparison of Japanese and U. S. experience.
The second section provides detailed technical
information on selected FGD installations visited
including plant/FGD specifications, performance
information and process flow diagrams. An
appendix provides further information concerning
members of the visiting task force, a listing of
plants visited, and numbers and capacities of FGD
systems in Japan.
energy status
Approximately seventy-five percent of the utility
power generated in Japan is fossil-fired
steam-electric (87,475 MW including those plants
under construction). Hydroelectric provides
another 20 percent of the power, with nuclear
steam-electric producing the remaining five
percent.
total steam electric
power fuels
3% coal-fired
-------
Oil, most of it imported, fuels 85 percent of the
country's total fossil-fired steam-electric power. A
rapid increase in energy usage in recent years has
meant a growing dependence on imported oil
(presently over 70 percent of Japan's total energy
supply). In an effort to reduce this dependence, the
Japanese Government initiated, in 1974, the
"Sunshine" Project promoting research and
development on alternative energy technologies,
including solar, geothermal, and coal
liquefaction/gasification.
Low sulfur fuels, such as naptha and liquified
natural gas (LNG), are also burned by some of the
major power companies in heavily polluted
sections of their service areas. These fuels account
for 12 percent of the fossil fuels used for the
production of steam-electric power, and imports
also are rapidly increasing in this area.
ppro
(yearly average)
.05*
.04
.03"
.02 •
.01
comparative
ambient
SO2 standard
Although, coal-fired utility capacity presently
accounts for only about three percent of the total
steam electric power produced, it is likely that this
percentage will significantly increase in the years
ahead as the price of oil continues to increase.
Over 50 million tons of coal were mined yearly in
Japan during the early 1960s. That dropped to
around 20 million tons per year as oil imports
increased. Though Japan currently imports over 60
million tons of coal annually, most of it is for coke
production in the steel industry. As part of the
"Sunshine" Project, the Ministry of International
Irade and Industry (MM!) is promoting increased
coal use by utilities. Tb this end EPDC, the
government/industry funded Electric Power
Development Company, has constructed and is
operating a number of coal-fired power plants.
SOz pollution and regulation
Increasing use of coal by utilities means increasing
potential for sulfur oxides pollution and the need
for emission controls. Such pollution and emissions
regulation are not new to Japan. Since 1967
environmental laws and standards have helped
abate a serious sulfur dioxide (SO2) pollution
problem arising from industry's booming post-war
recovery This improvement reflects the effects of
burning imported low sulfur oil, the widespread
application of FGD systems, and hydrodesulfuriza-
tion of residual oil.
Sulfur oxides emissions were reduced 50 percent
between 1970 and 1975 as regulations became
more restrictive. This occurred despite a 120
percent increase in energy consumption during
that period. The ambient SO2 standard was
tightened from 0.05 parts per million (ppm) to 0.016
ppm {yearly average) in 1973 with a target
achievement date of 1978. The daily average may
not exceed 0.04 ppm, the hourly average 0.10 ppm.
The standard is much more stringent than the
standards in the U.S., 0.03 ppm (yearly average),
or West Germany, 0.05 ppm.
The central government enforces the SO 2
emission standard through the "K value" system.
Under this system, a specific allowable volume of
SO 2 emission is calculated for each emitting
source within 17 geographical areas. The allowable
-------
national air
sampling network
8 rural monitoring stations
provide readings on
natural sulfur levels
in unpolluted regions
15 urban monitoring stations
provide sulfur level
readings in industrial areas
SO 2 is a function of stack height and a constant
factor, K, specified for each geographical region.
The K-factor value depends upon air quality and
the number of emission sources within each
region. The most heavily industrialized regions
have the lowest K value. These K values have been
revised downward almost yearly since 1974 to
achieve the targeted 1978 ambient standard.
In large cities and heavily industrialized areas,
however, this K-value emissions standard has
proven unsatisfactory in keeping the ambient SO2
concentrations below the 0.04 ppm daily average.
Therefore, in late 1974 the central government
issued a new regulation restricting the total mass
of SO 2 emissions in each of the 11 most poluted
regions. With its application to 13 more regions
since then, a total of 34 percent of all of the sulfur
oxides emission sources in Japan are now
regulated by the mass standard. The new
regulation has been instrumental in attaining the
ambient standard in 98 percent of the regions.
Where total mass regulations are not in effect
SO 2 emissions continue to be regulated by the K
value system. Agreements between industry and
prefectural or city authorities establish standards in
these regions for larger, particularly new plants.
These standards are sometimes more stringent
than those of the central government. For example,
many power plants in remote areas are required to
use oil with a sulfur content less than 0.3 percent
or to install FGD to attain the equivalent sulfur
reduction.
-------
growth of FGD plants in Japan
1200
1100
1970
1971
1972
1973
1974
1975
1976
1977
1978
Fuel type is also subject to regulation. For
example, plants smaller than 0.4 MW equivalent
are required to use low sulfur oil. For large plants
the prefectural governor has established specific
allowable emission rates that can be met only by
using ultra low sulfur oil or higher sulfur oil in
combination with FGD. New plants in the most
restrictive regions must attain a standard that is
equivalent to burning oil of less than a 0.079
percent sulfur content. If more restrictive standards
should be required for these regions, FGD may not
provide adequate control.
The "Pollution-Related Health Damage
Compensation Law," in effect since 1974, is
another factor in SO x emissions abatement. In
certain designated polluted areas, inhabitants
suffering from pollution-related illnesses receive
medical care financed through special taxes. These
taxes are assessed on total amount of SO2 emitted
by certain plants (those emitting more than 5,000
normal cubic meters per hour (Nm3/hr) of flue gas,
even though emission regulations are being met.
This tax rate in the more heavily polluted areas
has increased by a factor of 10 since 1975.
Consequently, a number of companies presently
meeting the regulations are considering installing
FGD plants, as cost of FGD may be offset by the
resulting decrease in the tax.
FGD control technology
Rapid progress was made in installation of FGD
control systems between 1970 and 1975, when the
number of plants grew from less than 100 to over
1,000. This growth stemmed largely from two
factors: sizable cost savings in utilizing high sulfur
fuels in combination with FGD as opposed to
using low sulfur fuels and increasing confidence in
the reliability of FGD system operation.
As of December 1978, over 500 major FGD
plants, having a combined capacity of about
30,000 MW, were operating in Japan. There were
also about 500 small systems installed in plants
averaging 6 MW of equivalent capacity. Of the
total FGD capacity, approximately one third or
10,076 MW is installed in utilities. Another 3,750
MW are under construction or planned. The
remaining FGD capacity is in industrial boilers,
sintering plants, smelters, and sulfuric acid plants.
-------
The FGD capacity installed, under construction,
and planned in the Japanese utility industry
represents about 16 percent of its fossil-fired
steam generating capacity. In the U. S., there is
15,773 MW of FGD capacity with an additional
54,327 MW under construction or planned. This
70,010 MW represents 26 percent of the total U. S.
coal-fired generating capacity.
Growth in FGD capacity has begun to decline in
Japan recently for several reasons. Ambient S02
concentrations in large cities and industrial
districts dropped to the 0.02 ppm to 0.03 ppm
range; this is close to achieving the ambient
standard of 0.016 ppm. The recent downturn in the
Japanese economy has affected FGD plant
construction. Low sulfur fuels are being burned
more extensively as low sulfur and high sulfur oil
price differentials decrease and FGD by-products
saturate their markets. And stringent nitrogen
oxides (NO *) emission standards have encouraged
development of processes simultaneously removing
NOX and SOX. Rather than install separate NOX
and SOX control systems, industry is awaiting
demonstration of the new technology. Present
government policy mandating increased use of
coal for power production, however, will likely
reduce this decline in FGD growth rate.
Among the FGD processes in use in Japan are
the lime/limestone process producing usable
gypsum (45 percent of total FGD plant capacity);
the indirect lime/limestone process—double alkali
type (15 percent); regenerable processes producing
sulfuric acid; elemental sulfur, and ammonium
sulfate as by-products (13 percent); and sodium
scrubbing to by-produce sodium sulfite or sulfate
(27 percent). The sodium sulfite is used by paper
mills. Sodium sulfite is also oxidized to sulfate for
use in the glass industry or discharged in treated
wastewater.
The FGD processes in four Japanese plants are
described in greater detail in Section E. These
plants are included because of their similarity to
U. S. utility scrubber applications. They are all
coal-fired. Three are utility applications using the
limestone process and producing gypsum. The
fourth is an industrial boiler application that uses
the lime tnrowaway process producing sludge.
significance
Japanese FGD technology is successful in both
utility and industrial applications. Scrubber
installations on coal fired plants routinely attain
SO2 removal efficiencies in excess of 90 percent
and operational reliabilities of over 96 percent.
Installations on oil fired and industrial units
achieve similar efficiencies and reliabilities.
Although Japan and the U. S. have emerged as
world leaders in developing and applying FGD
technology, Japan has generally moved more
rapidly than the U. S. because of its more serious
air pollution problem. Technical, administrative,
and governmental factors must be considered
when comparing the U. S, with the Japanese
experiences in FGD technologies.
% of total fossil-fired
utility capacity*
15"
FGD control:
U.S. & Japan
planned or
under
construction
(54,237 mw)
planned or
under
construction
(3,750 mw)
31
United States
Japan
'total U.S. capacity—450,000mw(265,000mwcoal-fired)
total Japanese capacity—87,475mw (74,354mw oil-fired)
-------
Technical factors—Three significant factors
affect the performance of Japanese vs. U. S. FGD
systems:
• Sulfur content of the fuels
• Closed vs. open loop operation
• Fuel and absorbent controls
Sulfur content of coal burned in Japanese utility
and industrial boilers is significantly though not
drastically lower than that used in U. S. power
generating systems. Although this sulfur content
ranges from 0.7 percent to 2.4 percent, a high ash
content and intermediate heating values of
Japanese coal give an SO2 concentration in the
flue gas equivalent to that produced from U. S.
coals of somewhat higher sulfur content. For
example, the 2.4 percent sulfur coal burned in a
Japanese aluminum plant produces an inlet SO2
concentration approximately equivalent to a 3.0
percent sulfur midwest or eastern U.S. coal.
Japanese FGD systems generally cleanse flue
gases having SO 2 inlet concentrations of 400 to
2300 ppm—a range of inlet sulfur values not
dissimilar to many of those in U. S. FGD systems
on coal-fired utility boilers. Japan has no
experience with the higher sulfur coal such as
those used by many U. S. utilities. The higher SO2
content flue gases associated with burning such
coal are more difficult to scrub due to mass transfer
limitations.
The successful operation of lime/limestone
scrubbers in Japan has often been attributed to
their generally open loop operation entailing
purging large quantities of process liquids. In order
to evaluate the Japanese FGD systems on a basis
comparable to those in the U. S., however, it is
necessary to relate the quantity of gypsum
produced by an FGD system to the amount of
process liquids purged, thus establishing an
effective pond disposal solids concentration. When
evaluated on this basis, the quantity of liquid
purged in Japanese FGD systems is often quite
similar to that removed in a typical closed loop
U. S. scrubber system employing ponding.
Fuel and absorbent controls constitute the third
technical factor affecting FGD systems perform-
ance. The suppliers and users of Japanese FGD
systems consider the scrubber operation as
essentially a chemical process. Raw materials
flowing into the scrubbers are thus carefully
controlled to minimize imbalances in the chemical
reactions and to maximize efficiency. Predominant
use of oil as fuel simplifies this control. When coal
is used, blending prior to combustion ensures a
relatively constant SO2 loading into the scrubbing
process. Utilization of only dry prepulverized
limestone meeting strict size and composition
specifications reduces variability in quality of the
absorbent.
Administrative factors—Contractual
arrangements for FGD systems in Japan and the
U. S. differ somewhat in:
• Design and purchase
* Operation and maintenance
The Japanese prepare only general system
specifications, and also demand that scrubber
systems perform with a reliability compatible with
that of the power generating plant. EPDC, for
example, requires the system supplier to correct at
his expense any process/equipment problems
occurring within a year of EPDC's acceptance of
the system. Japanese scrubber systems may
initially be more expensive than U. S. systems, but
they usually require less modification. The fact that
one supplier (MHI) provides half the lime/limestone
scrubbing systems in Japan undoubtedly enhances
reliability.
Equally important, the Japanese recognize the
need for specially trained personnel to operate and
maintain FGD systems. Such personnel are
concerned exclusively with the scrubbing systems
and are not rotated into other power plant duties
as is generally the case in the U. S. In some cases,
contracts are negotiated specifically for such
services.
-------
key factors in Japanese
FGD experience
Governmental factors—Within the context of
Japanese governmental/industrial relations, the
following have been significant in achieving FGD
success:
• Monitoring and enforcement
• SO 2 emission tax
• Government/industry cooperation
Japan employs a stringent, continuous monitoring
and enforcement program. Many prefectural
governments operate an environmental research
center (subsidized by the central government),
some of which are directly linked via telemetry
systems to automatic monitoring stations located
at major emission sources and key ambient sites.
Emission sources must remain in constant
compliance, or violations result in fines and/or
forced shutdown of the source. Violations,
consequently, rarely occur.
As outlined earlier, Japan taxes certain plants
emitting more than 5000 Nm3/hr of flue gas; tax
proceeds are applied to medical care of those
people suffering from pollution related illnesses.
Taxes vary among the industrialized areas, one
area having a rate of 345 yen/Nm3 of SO x emitted.
In this area for a typical 150 MW plant emitting 100
Nm3/hr of SOX after 95 percent SO2 control, the
daily tax exceeds 828,000 yen ($4200). A number of
companies are considering installing FGD systems
despite present compliance with SOX regulations,
because the resulting reduction in tax obligation
may well offset the cost of FGD.
A sincere cooperative spirit appears to exist
between Japanese industry (users and suppliers)
and the regulatory agencies. And the central
government has assisted industry in many
instances in constructing pollution control facilities
by providing low interest loans and allowing
seven-year depreciation of the facilities. MM has
had a major role in promoting cooperation.
The need for environmental controls for sulfur
oxides was at a crisis level in Japan in the late
1960s. Japanese industry recognized the crisis and
accepted the goal of a cleaner environment.
Utilities and industry have made a sincere effort to
acquire the best FGD systems available and to
maintain good operability.
-------
-------
plants visited
During the first part of February 1978, a task force
of representatives from the U. S. Environmental
Protection Agency, Electric Power Research
Institute, and the Tennessee Valley Authority
visited 11 flue gas desulfurization plant sites in
Japan. In addition, they conversed with employees
of most of the major scrubber system suppliers, the
Japan Environmental Agency, the Electric Power
Development Corporation (EPDC), the Ministry of
International Trade and Industry, and the Aichi
Prefecture Environmental Research Center, The
visits to the EPDC and Mitsui Aluminum plants
were included because they operate coal-fired
power plants.
The government-financed EPDC was created in
1952 to alleviate the serious power shortage in
Japan during the post-war period of
reconstruction. It undertakes the development of
large scale or difficult power development schemes
or multiple purpose projects incorporating
integrated national land development plans. With
power development schemes totaling some 800
billion yen ($3.36 billion/1978), the EPDC has
completed 7000 MW of generating capacity at 50
sites. This includes coal-fired power plants
constructed in accordance with the government's
policy to cut dependence on imported oil. The
EPDC assists in stabilizing electricity supply
through sale of electricity to private utility
companies, interchange of power between regions,
and improved plant efficiency.
The scrubber systems of the three EPDC utilities
and of the Mitsui Aluminum Company represent
the successful application of FGD to coal-fired
generating units. Technical information on these
FGD installations follows. A comparison of the
characteristics of each of these plants (as well as
the others visited) is provided in Table 1 in the
Appendix.
Control Boards and Generators, Chubu Electric Company (Courtesy of Japanese Embassy)
11
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EPDC Isogo station
EPDC's Isogo Power Station is located in Yoko-
hama, a heavily industrialized area near Tokyo. The
environmental standards for the area are the most
stringent in the country. SO2 emission from the
plant is limited to 48 Nm3/day—equivalent to 60
ppm.
The plant consists of two 265 MW units. Boilers
normally burn coal but can also be fired with
low-sulfur oil. Occasionally a 50-50 coal and oil
mixture is used depending on fuel availability and
cost. Maximum sulfur content in coal used is 0.6
percent; it normally ranges from 0.3 to 0.5 percent.
The FGD system employed is the Iffl Ghemico
process with limestone as the absorbent.
Electrostatic precipitators are also used in
conjunction with the two-stage ventuii scrubber to
reduce ash loading to 0.05g/Nm3. Emission
requirements have effectively been met by the
FGD system. Reliability has been near 100 percent
since startup in 1976.
EPDC Isogo Power Station
Process description—The Isogo FGD system
has two equipment trains, each treating 900,000
Mm3 of flue gas per hour. Previous existing induced
draft fans supply gas to new booster fans to
accommodate an FGD system pressure drop of 820
mm H2O. The gas is cooled and cleaned in
two-stages, fixed-throat venturi absorbers, with
liquid-gas ratio in each stage of about 70 gal/1000
ft3. The absorbers are of the Chemico type with
pie-shaped chevron mist eliminator elements
located around the circumference of the vessel at
the scrubber outlet. Below the fixed throat venturi
section, the superficial velocity is about 10 feet/sec.
About 70 percent of SO2 removal takes place in
the first stage, where pH is 5.4. The pH in the
second stage is controlled at about 7. Facilities for
sulfuric acid addition to adjust pH are provided,
but have not been needed. Overall stoichiometry is
about 1.05.
Pulverized limestone (100 percent through a 325
mesh) to slurried with fresh water to 15 percent
solids. This slurry is then fed to the second-stage
absorber, and the effluent is pumped to the first
stage for maximum utilization of the limestone.
Fresh water, used for a mist eliminator wash,
dilutes the recirculated slurry to about 7 percent
solids.
A bleed stream from the first stage absorber is
treated in a forced oxidation system to produce
gypsum. Gypsum is dewatered in thickeners and
centrifuges; except for a blowdown stream, the
clarified liquid is then returned to the absorber
system. The blowdown is needed primarily to
control chloride concentration below 5000 ppm.
The liquid is discharged through a waste water
treatment facility where the suspended solids,
BOD, COD, and pH are controlled. Dissolved solids
are not regulated.
The gypsum produced is low grade because of
the high ash content (about 16 percent) and the
relatively high moisture content (15 percent).
However, it is suitable for use in cement and is
sold for the cost of delivery
The scrubber is constructed from mild, steel and
is flake lined (applied with a brush). Piping is
rubber lined. Pumps have stainless steel housings
and silicon carbide impellers.
12
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ISOGO PLANT
CRUSHED
LIMESTONE
(CaCos)
PUMP i
BLOW «
DOWN
STREAM
SLOWDOWN
WASTE
WATER FOR
TREATMENT
In order to emphasize the
process flow while simplifying
the presentation of these systems,
all holding tanks have been
eliminated except those in which a
mixing function is performed. Booster fans
and pumps are generally excluded.
Isogo — design/performance data
SOz control system units
nos. 1 & 2
flue gas rate (Nm3/hr) 879,000 each
inlet SOX (dry ppm) —
inlet paniculate (g/Nm1) —
inlet gas temperature (°C) 143
scrubber type venturi
scrubber capacity (Nm3) 900,000 each
absorbent limestone
outlet SO, at stack (dry ppm) —
average SO2 removal efficiency (%) 90
liquid purge rate (tons/hr) —
utility consumption
electric power (kw) 6,400 each
water (tons/hr) —
limestone/lime (tons/day) 50 each
gypsum production (tons/day) 120 each
availability {%} near 100
bolter
power generation capacity (MW) 265 each
electrostatic precipitator efficiency (%) 96.7
coal
heat value (kcal/kg) 6,200
sulfur content (%) 0.2-0.6
ash content (%) 16
load variation (%) 75-50
13
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EPDC Takasago station
The lakasago power station is located near Himeji
on the Seto Inland Sea, The station has two 250
MW coal-fired units that burn a blend of domestic
coals averaging 2.0 percent in sulfur content,
SOX emissions for the area were previously
restricted to 400 Nm3/hr. Under more stringent
total mass emission regulations effective in April
1978, allowable emissions have been reduced to
243 Nm3/hr (136 ppm) at full load.
The FGD systems, of the Mitsui-Chemico
limestone-gypsum process, have consistently
achieved average SO2 removal efficiencies
exceeding 93 percent while maintaining 99
percent operability. Systems maintain particulate
outlet concentrations below 0.05 g/Nm3.
EPDC Takasago Power StaSon
Process description—Flue gas from the
Ikkasago boiler is split into three streams and sent
to the first stage scrubber (75 percent), pH control
tower (20 percent) and oxidation tower (5 percent).
The flue gas exiting these vessels is then merged,
passes through the second-stage scrubber and is
reheated directly (using 0.3 percent sulfur oil) to
85° C prior to passing into the stack. The process is
characterized by the pH control tower and
oxidation reactor, which utilize SO2 from the flue
gas to lower the slurry pH to 5.8, thus increasing
alkali utilization without using sulfuric acid.
Preground limestone (90 percent through a 325
mesh) is slurried on-site to 15 percent solids using
centrate and thickener supernate and is fed to the
second-stage scrubber at a stoichiometry of
1.0-1.05 based on the inlet SO2 - Process control is
accomplished by measurement of flue gas volume
and SO 2 concentration, which automatically
determines the slurry make-up volume reo^iired.
Fine tuning of the make-up feed rate is
maintained by pH control in the second-stage
scrubber, which is operated at pH 6.2 and
liquid/gas ratio of 6.5 liters/Nm3. Recycle slurry
from the second stage is fed to the first-stage
scrubber, which operates at pH 6.0 and lio^ud/gas
ratio of 6.5 liters/Nm3. The recycle slurry is
maintained at 5-6 percent solids. The gypsum
slurry from the oxidizer is pumped to a thickener,
concentrated to a 20 percent slurry and dewatered
by centrifuge, producing gypsum containing
approximately 10 percent moisture.
Thickener overflow and the centrate are
returned to the process for limestone slurry
make-up absorber liquid level adjustments and
mist-eliminator washing. This supernate is also
blown down (5 tons/hr for Unit No. 1,10 tons/hi for
Unit No. 2) to maintain chloride concentration
below 8000 ppm.
Four-pass chevron-type mist eliminators are
provided for the second stage scrubber, which is
secruentialiy washed with process liquid and fresh
water.
14
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TAKASAGO
PLANT
FLUE GAS
FROM
BOILERS
FIRS
STAGE
SCRUBBER
(ABSORBER)
SECORB
STAGE
^£^ SCRUBBER
(ABSORBER)
_ f=3. WASTE
sLU'DOWN I WATER FOR
TREATMENT
CENTRIFICAU
SEPARATOR W
SUM GYPSUM
in order to emphasize the
process flow while simplifying
the presentation of these systems,
all holding tanks have been
eliminated except those in which a
mixing function is performed. Booster fans
and pumps are generally excluded.
Takasago—design/performance data
SOz control system
flue gas rate (Nm3/hi)
inlet SO* (dry ppm)
inlet paniculate (g/Nm3)
inlet gas temperature (°C)
scrubber type
scrubber capacity (Mm3)
absorbent
outlet particulate (g/Nrn3)
outlet SO* at stack (dry ppm)
average SO2 removal efficiency
liquid purge rate (tons/hi)
utility consumption
electric power (kw)
water (tons/hr)
limestone/lime (tons/day)
gypsum production (tons/day)
availability (%)
units
nos. 1 & 2
799,000
1500-1700
0.1
150
2-stage venturi
842,000
limestone
>0.05
>100
93
5
6,500
52
125
230
98.8
boiler
power generation capacity (MW) 250 each
coal
heat value (kcal/kg) 6,000 (est.)
sulfui content (%) 2.0
load variation (%) 100-50
15
-------
EPDC Takehara station
Located near Mihaia on the Seto Inland Sea, the
Takehara station consists of a 250 MW coal-fired
unit and a 350 MW oil-fired unit. Since there are no
large cities in the vicinity of the station,
environmental regulations are relatively mild. The
central government restricts emissions to 468
Nms/hr (600 ppm) and 503 Nm3/hr (620 ppm) for
Units No. 1 and 2, respectively. An agreement with
the city and prefectural governments, however,
limits Unit No. 1 SOX emissions to 195 Nm3/hr (240
ppm).
A Babcock-Hitachi limestone gypsum system
operates on Unit No. 1. Coal burned in Unit No. 1 is
domestic (Kyushu) blended on-site to achieve 2.0
percent sulfur. The Unit No. 1FGD system
achieves an operabHity in excess of 97 percent and
an SO 2 removal efficiency exceeding 93 percent.
Unit No. 2, burning 1.0 percent sulfur oil, has no
FGD system at present.
Process description—At the Takehara Station,
booster fans supply gas to the scrubber from 98%
efficient electrostatic precipitators. The gas
contains approximately 200 gm/Nm3 of paniculate
matter and 1,730 Nm3/hr of sulfur dioxide. The
scrubber system consists of two identical
scrubbing trains each designed to scrub about
400,000 Nm3/hr. Upon entering the scrubbing
system, the flue gas is split equally, each portion
entering a prescrubber venturi section where the
gas is quenched. The precooled flue gas then
proceeds to a second-stage scrubber containing
perforated plates that provide good gas-liquid
contact, Gas flow through each scrubber train is
controlled by separate fans.
Prior to exiting the second stage, the flue gas
passes vertically through a horizontal mist
eliminator consisting of finned tube bundles. The
cleaned gas is then reheated to 120° C by direct
oil-fired reheaters before exiting through a
200-meter stack. Total pressure drop across the
system is reported to be 650 mm H2O (230 mm
H2O in the prescrubber and 385 mm H2O in the
scrubber). Fresh water is used to sequentially
wash the mist eliminator sections. A complete
wash cycle is about 2 hours and requires about
5-10 tons of fresh water per train.
The scrubbing system uses a limestone slurry of
10 percent solids. The slurry from the second-stage
recycle tank, which has a liquid/gas ratio of about
2 liters/Nm3, is bled to the first stage prescrubber
and recycled at a liquid/gas ratio of about 2
liters/Nm3. Slurry from this prescrubber recycle
tank is continuously bled to a pH adjustment tank,
where sulfuric acid is added to lower the pH before
the slurry is pumped to an oxidation tower. After
passing through the oxidation tower, the slurry is
bled to a thickener. The supernatant liquid is
returned to both recycle tanks and the underflow is
then pumped to centrifuges, where final
dewatering of the gypsum is accomplished by
batch operation. The byproduct gypsum contains
about 10 percent moisture and is sold for use in the
cement and wallboard industries. Supernatant
liquid from the centrifuges is pumped to the
limestone preparation tank to slurry the limestone.
This liquid contains substantial gypsum particles
that act as seed crystals to control scale formation
in the scrubber and to control size and type of
gypsum crystals ultimately produced. In the
second-stage recycle tank slurry, pH is controlled
at 6.0; in the prescrubber recycle tank, pH is
maintained at 5.0.
Process control is accomplished by measure-
ment of flue gas volume and SO2 concentration,
which automatically determines volume of
make-up slurry required. Liquor flow rate is kept
constant during gas turn-down.
Energy requirements for the FGD system
(excluding reheat) were reported as 3.1 percent of
unit power generating capacity.
Plant operators routinely blend coal to maintain
inlet flue gas sulfur dioxide concentrations of
between 1550 and 1650 ppm. The plant has strict
specifications for the pulverized limestone
delivered dry to the plant site. Quality control of
this limestone assures 95% through a 325 mesh
screen, a minimum of 55.4 percent CaO, and
impurities limited to 1.14 percent. Supernatant
liquid is continuously blown down at a rate of 10-15
tons/hr to maintain a chloride level of 3500 ppm in
the recirculated slurry.
16
-------
TAKEHARA
PLANT
In order to emphasize the
process flow while simplifying
the presentation of these systems,
all holding tanks have been
eliminated except those in which a
mixing function is performed. Booster fans
and pumps are generally excluded.
Takehara—design/performance data
SO2 control system units
DOB. 1 & 2
flue gas rate (Nms/hr) 809,000
inlet SOX (dry ppm) 1500-1700
inlet paniculate (g/Nm3) 0.36
inlet gas temperature (°C) 140
prescrubber type venturi
scrubber type perforated plate
scrubber capacity (Nm3) 852,000
absorbent limestone
outlet paniculate (g/Nm3) >0.03
outlet SOX at stack (dry pprn) >100
average SO2 removal efficiency (%) 93
liquid purge rate (tons/hr) 10-15
utility consumption
electric power (kw) 7800
water (tons/hr) 56
limestone/lime (tons/day) 130
gypsum production (tons/day) 225
availability (%) 97
boiler
power generation capacity (MW) 250
electrostatic precipitator efficiency (%) 98
coal
heat value (kcal/kg) 6000
sulfur content (%) 2.0
ash content (%) 23
load variation (%) 100-40
annual load factor (%) 75
-------
Mitsui Aluminum Company, Ltd.
The MiiM Power Plant in Omuta was built by the
Mitsu Aluminum Company to provide an assured
supply of electricity to its aluminum smelter. It is
the largest privately-owned power station in Japan.
Unit No. 1 (156 MW) is equipped with a
Mitsui-Chernico lime scrubbing system using
carbide sludge waste from a nearby chemical
plant. Unit No. 2 employs a Mitsui-Ghemico
limestone process by-producing gypsum that is
sold for use in the wallboard and Portland cement
industries. Both FGD units have achieved
essentially 100 percent operability (except for one
10-day outage of Unit No. 2). Their S02 removal
efficiencies have consistently been in excess of 90
percent.
Mitsui Aluminum Co.. Ltd-, Miiki Power Plant
Process description—Unit 1—Unit No. 1 of the
MiiVd Power Plant consists of two scrubber trains,
each capable of handling 75 percent of total flue
gas capacity (512,000 Nm3/hr). Of additional
interest is the 25-MW slip stream prototype
subsequently added to study the limestone/
gypsum process. Although this prototype is no
longer in operation, reportedly it could be restarted
to provide 100 percent flue gas treatment in
conjunction with one train should the second train
require shutdown.
Flue gas passes through a two-stage venturi
scrubber (450 mm H2O total pressure drop), where
SO 2 and residual particulate are removed. The
cleaned flue gas is reheated to 85° C prior to
discharging through a 130-meter stack.
The system uses a mixture of wet (50-60 percent
moisture) and dry (47 percent moisture) carbide
lime, which is adjusted to a final slurry
concentration of 15 percent. Make-up slurry feed
rate is manually controlled by recycle slurry pH,
which is maintained at 8 (although designed for
6.8). Suspended solids content of the recycle slurry
is normally maintained at around 5-6 percent by
weight. Liquid/gas ratio for each stage is around
40 gal/1000 standard cubic feet. Delay tank
residence times for the first and second stages
were reported as 20 and 4 minutes, respectively. A
bleed stream from the first stage delay tank is
transported to a settling pond, where the
supernatant liquid is returned to the process for
carbide lime make-up, absorber liquid level
adjustments, and mist eliminator washing.
Four-stage chevron-type mist eliminators are
provided for both first and second stages and are
intermittently washed with fresh water and
recirculated pond liquor. Gas velocity through the
mist eliminator is around 2.7 meters/sec.
Process description—Unit No. 2—The
process description for Unit 2 is not included here
because it was the same limestone process as the
lakasago plant, previously described.
18
-------
MITSUI UNIT 1#
In order to emphasize the
process flow while simplifying
the presentation of these systems,
all holding tanks have been
eliminated except those in which a
mixing function is performed. Booster fans
and pumps are generally excluded.
Miiki unit 1 — design/performance data
SOz control system unit no. 1 unit no. 2
flue gas rate (Nms/hr) 512,000 552,000
inlet SO, (dry ppm) 2100-2300 1900-2100
inlet partioulate (g/Nm3) 0.6 0.6
inlet gas temperature (°C) 136 138
scrubber type 2-stage venturi 2-stage venturi
scrubber capacity (Nm3) 385,000 x 2 552,000 x 1
absorbent carbide lime limestone
outlet paniculate (g/Nm3) >0.06 >0.06
outlet SO, at stack (dry ppm) >200 >200
average SOz removal efficiency (%) 90 + 90 +
liquid purge rate (tons/hr) 90 20
utility consumption
electric power (kw) 3650 4240
water (tons/hr) 36.5
bunker c oil (kl/day) 15 18
limestone/lime (tons/day) 110 110
catalyst (kg/hi) 20
gypsum production (tons/day) 180
availability (%) 100 99
(100 since 11/75)
bolter
steam generation capacity (tons/hi)
power generation capacity (MW)
electrostatic precipitator efficiency (%)
coal
heat value (kcal/kg)
sulfur content (%)
load variation (%)
490
156
98.6
5500-5800
2.4
100-50
(usually 100)
550
175
98.6
5500-5800
2.4
100-50
(usually 100)
19
-------
appendix
task force membera
Michael A. Maxwell (Chairman)
Chief, Emissions/Effluent Technology Branch
Industrial Environmental Research Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina
H- William Elder
Manager, Emission Control Development Projects
Division of Chemical Development
Tennessee Valley Authority
Muscle Shoals, Alabama
Thomas M. Morasky
Manager, SO, Subprogram
Air Quality Group
Electric Power Research. Institute
Palo Alto, California
Dr. Jumpei Ando (Consultant)
Professor, Chuo University
Tokyo, Japan
plants visited
Plant
Owner
EPDC
EPDC
EPDC
Plant
Site
Takehara
Takasago
Isoga
Mitsui Aluminum Omuta
Mitsui Aluminum Omuta
Chuba Electric Owase
Plant FGD
Type Process
C, U Babcock-Hitachi
C, U Chemico-Mitsui
C, U Chemico-IHI
C, I Mitsui-Chemico
C, I Chemico-Mitsui
O, U MHI
Chugoku Electric Shimonoseki O, U MHI
Idemitsu Kosan Chiba
O, I Chemico-Mitsui
Chuba Electric Nishinagoya 0, U Wellman-MKK
Naikai Tamano O, i Dowa
Dowa Mining Okayama A Dowa
Japan Exlan Saidaiji O, I Kawasaki
Capacity
(MW)
250
250
(2 units)
265
(2 units)
175
156
375
(2 units)
400
160
220
30 (eq)
50 (eq)
80
Absorbent
CaCCh
CaCOa
CaCOs
CaCOs
Carbide lime
Ca(OH)2
CaCOs
MgO
NasSOs
AMSO-Oa- CaCOa
Alz(SO«)3- CaCOs
MgO - CaCOa
By-Product
Gypsum
Gypsum
Gypsum
Gypsum
Sludge
Gypsum
Gypsum
Sulfur
H2SO4
Gypsum
Gypsum
Gypsum
Year
Operational
1977
1975/76
1976
1975
1972
1976
1977
1975
1973
1976
1974
1976
C = coal, O = oil, U = utility boiler, I = industrial boiler, A = HzSO4 plant
20
-------
number/capacities (1,000 Nm*/hr) of FGD installation!
Plant Constructor
Mitsubishi Heavy Industries (MH1)
Ishikawajima H. I. (1HI)
Hitachi, Ltd.
Mitsubishi Kakoki (MKK)
Kawasaki Heavy Industries
Tsukishima Kikai fTSK)
Chiyoda Chemical Engineering
& Construction
Oji Koel
Fuji Kasui Engineering
Kurabo Engineering
Mitsui MBke-Chernico
Ebara Manufacturing
Nippon Kokan(NKK)
Kureha Chemical
Showa Denko
Cadlius
Sumitomo (SCEC)-Wellman
Mitsui Metal Enginnering
Kobe Steel
Japan Gasoline
Dowa Engineering
Niigata Iron Works
Mitsui Shipbuilding
Sumitomo Heavy Industries
Total
1 Process type
Byproduct
steam power capacity vs. FGD capacity
Indirect
Jmq/J-
33
17
13
2
4
1
7
4
3
4
5
1
94
mestone'
Gypsum2
(18,270)
(4,445)
(6,940)
256
(756)
(3,954)
(2,744)
*
(245)
(1,006)
(1,125)
(330)
(40,171)
time/Limestone
Gypsum
6
4
14
5
11
1
5
1
47
(5,450)
(398)
(4,459)
(413)
(1,914)
(150)
(453)
(185)
(13,422)
Regenerate;
HjSOt, S
2
13
1
1
1
2
6
2
1
1
30
(590)
(6,478)
(88)
(18)
(500)
(1,990)
(1,288)
(130)
(125)
(150)
(11,357)
Once through
NaiSOa
3 (292)
79
15
41
7
40
57
6
106
10
6
8
5
8
1
392
(4,351)
(603)
(913)
(256)
(4,042)
(4,280)
(270)
(3,751)
(1,167)
(62)
(1,431)
(1,372)
(1,291)
(160)
(24,241)
Total
36 (18,562)
96
30
56
17
46
14
57
13
112
5
21
12
8
5
8
6
6
5
Z
5
1
1
1
563
(8,796)
(8,133)
(7,643
(6,380)
(4,528)
(4,459)
(4,280)
(4,224)
(4,182)
(3,244)
(3,081)
(2,447)
(1,431)
1,372
(1,291)
(1,288)
(1,136)
(1,125)
(455)
500)
185)
160)
(150)
(89,138)
*500 add'l small FGD plants
Total power capacity (MW)
Power Company
Hokkaido
Tohoku
Tokyo
Chubu
Hokuriku
Kansai
Chugoku
Shikoku
Kyushu
EPDC
Niigata
Showa
Toyama
Mizushima
Sumitomo
Sakata
Fukui
Others
TOTAL
Existing
1,270
3,925
19,167
9,933
1,412
10,672
3,777
2,687
4,500
1,430
350
550
750
462
368
0
0
5,512
66,775
Under
Construction
1,225
1,200
4,400
3,800
1,000
1,200
1,800
450
2,700
1,000
350
0
0
0
250
700
250
375
20,700
Total
2,495
5,125
23,567
13,733
2,412
11,872
5,777
3,137
1,376
2,430
700
550
750
462
618
700
250
5,887
87,475
FGD capacity (MW)
Existing
0
550
283
970
600
930
1,350
900
1,376
1,280
175
400
250
156
156
700
0
0
10,076
Under
Construction
525
350
0
0
500
0
700
0
250
1,000
175
0
0
0
0
0
250
0
3,750
Total
525
900
0
970
1,100
930
2,050
900
1,626
2,280
350
400
250
156
156
700
250
0
13,826
(%)
21.0
17.6
1.2
7.1
45.6
7.8
36.8
12.5
22.6
93.8
50.0
72.7
33.3
33.8
25.2
100.0
100.0
0.0
15.8
21
-------
FGD systems in Japan
Boiler
Power company
Tohoku
Tohoku
Tohoku
Tohofcu
Totiaku
Tokyo
Tokyo
Chubu
Chubu
Chubu
Hokuriku
Hokuriku
Hokuriku
Kansai
Kansai
Kansai
Kansai
Kansai
Kansai
Kansai
Kansai
Chugoku
Chugoku
Chugoku
Chugoku
Chugoku
Hokkaido
Shikoku
Shikoku
Kyushu
Kyushu
Kyushu
Kyushu
Kyushu
Kyushu
Kyushu
EPOC
EPOC
EPDC
EPDC
EPDC
EPDC
Niigata
Showa
Showa
Toyama
Mizushima
Sumitomo
Sakata
Sakata
Fukui
Power station
Shinsendai
Hachinohe
Niigata
Niigata H.
Akita
Kashima
Yokosuka
Nishinagoya
Owase
Owase
Toyama
Fukui
Nanao
Sakai
Amagasaki
Amagasaki
Amagasaki
Osaka
Osaka
Osaka
Kainan
Mizushima
Tamashima
Tamashirna
Shirnonoseki
Shimonoseki
Higashilornakomai
Anna
Sakaide
Karita
Karatsu
Karatsu
Ainoura
Ainoura
Buzen
Buzen
Takasago
Takasago
Isogo
Takehara
Matsushima
Matsushima
Niigata
lohihara
Ichihara
Toyama
Mizushima
Niihama
Sakata
Sakata
Fukui
No.
2
4
4
1
3
3
1
1
1
Z
1
1
1
8
1
1
1
3
2
4
4
2
3
2
2
1
1
3
3
2
2
3
1
2
1
2
1
2
1
1
1
2
1
1
5
1
5
3
1
2
1
47
MW
600
250
250
600
350
600
265
220
375
375
500
350
500
250
156
156
156
156
156
156
600
156
500
350
400
175*
500
450
450
375
375
500
375
500
500
500
250*
250*
265*
250*
500*
500"
350
150
250
250
156
156
350
350
250
FGD
MW
150
125
125
150
350
150
133
220
375
375
250
350
500
63
35
121
156
156
156
156
150
100
500
350
400
175
250
450
450
188
188
250
250
250
250
250
250
250
265
250
500
500
175
150
250
250
156
156
350
350
250
Process developer
Kureha-Kawasaki
Mitsubishi H. I.
Wellman-MKK
Mitsubishi H. J.
Kureka-Kawasaki
Hitachi-Tokyo
Mitsubishi H. I.
Wellman-MKK
Mitsubishi H. I.
Mitsubishi H, I.
Chiyoda
Chiyoda
Not decided
Sumitomo H. I,
Mitsubishi H, ,
Mitsubishi H. I.
Mitsubishi H. I.
Babcock-Hitachi
Babeock-Hltacni
Babcock-Hitachi
Mitsubishi H. 1.
Babcock-Hitachi
Babcock-Hitachi
Babcock-Hitachi
Mitsubishi H. 1.
Mitsubishi H. 1,
Not decided
Kureha-Kawasaki
Kureha-Kawasaki
Mitsubishi H, ,
Mitsubishi H. .
Mitsubishi H. .
Mitsubishi H. .
Mitsubishi H, ,
Kureha-Kawasaki
Ku reha-Kawasaki
Mitsui-Chemico
Mitsui-Chemico
Chemico-IHI
Babcock-Hitachi
Not decided
Not decided
MH1
Showa Oenio
Babcock-Hitachi
Chiyoda
Mitsubishi H. 1.
IHI
Mitsubishi H. 1.
Mitsubishi H. 1.
Not decided
Absorbent, precipitant
NazSOa, CaCOa
CaO
Na2SOa
CaCOs
NaaSOa, CaCOa
Carbon, CaCOa
CaCOa
Na2SOa
CaO
CaO
HzSO4, CaCOa
H2SO4, CaCOa
HzS04, CaCOa
Carbon
CaO
CaO
CaO
CaCOa
CaCOa
CaCOa
CaO
CaCOa
CaCOa
CaCOa
CaCOa
CaCOa
CaCOa
NajSOa, CaCOa
NazSOs, CaCOa
CaO
CaCOs
CaCOa
CaCOa
CaCOa
NajSOa, CaCOa
NazSOa, CaCOa
CaCOa
CaCOs
CaCOa
CaCOs
CaCOa
CaCOa
CaCOa
NazSOa, CaCOa
CaCOa
H2SO4, CaCOa
CaO
CaCOs
CaCOa
CaCOa
CaCOa
By-product
Gypsum
Gypsum
H2SO4
Gypsum
Gypsum
Gypsum
Gypsum
H2SO4
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
H2SO4
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsurn
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsurn
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Gypsum
Year of
completion
1974
1974
1976
1976
1977
1972
1974
1973
1976
1976
1974
1975
1978
1972
1973
1975
1976
1975
1975
1976
1974
1974
1975
1976
1976
1979
1981
1975
1975
1974
1976
1976
1976
1976
1977
1978
1975
1976
1976
1977
1980
1980
1975
1973
1976
1975
1975
1975
1976
1977
1977
'CoaHired boilers. Others are for oil-fired boilers.
-------
conversion factors
For convenience in comparing metric units with
English system units and Japanese yen with
dollars the following conversion factors may be
useful.
1 m (meter)
1m3
11 (metric ton)
1 kg (kilogram)
1 liter
1 kl (kiloliter)
3.3 feet
35.3 cubic feet
1.1 short tons
2.2 pounds
0.26 gafton
6.19 barrels
The capacity of flue gas desulfurization plants is
expressed in Nm3/hr (normal cubic meters per
hour).
The L/G ratio (liquid/gas ratio) is expressed in
liters/Nm3.
1 liter/Nms = 7.4 gallons/
thousand standard
cubic feet
When using cost data in this report the following
conversion should be used:
Yen/Dollar
238 (1978, first
Quarter)
INnrVhr
= 0.59 standard cubic
foot per minute
23
-------
for
further
reading
Elder, H. W. et al, Sulfur Oxide Control
Technology—Visits in Japan—
August 1972—Interagency Report,
October 30,1972.
An do, J , Recent Developments in
Desulfurization of Fuel Oil and Waste
Gas in Japan—1973, EPA-R2-73-229,
May 1973.
Hollinden, G. A. and Princiotta, F. T.,
Sulfur Oxides Control Technology—
Visits in Japan—March 1974,
Interagency Report, October 15,1974.
Ando, J. and Isaacs, G.A., SO?
Abatement for Stationary Sources in
Japan, EPA- 600/2-76-031a, January 1976,
Kawanishi, S., Environmental Laws
and Regulations in Japan, Japan
Environmental Agency Report, February
1976.
Ando, J. and Laseke, B. A., SOz
Abatement for Stationary Sources in
Japan, EPA-600/7-77-103a, September
1977.
Kagawa, T., Quality of the Environ-
ment in Japan—1977, Japan
Environmental Agency Report, November
1977.
Ando, J. "Status of SOX and NOX Removal
Systems in Japan," in Proceedings:
Symposium on Flue Gas
Desulfurization—Hollywood, Florida,
November 1977 (Volume 1)
EPA-60G/Y-78-058a, March 1978.
Ando, J. et al, SOx Abatement for
Stationary Sources in Japan—
EPA-600/7-78-210, November 1978.
Laseke, B. A., EPA Utility FGD Survey:
December 1977-January 1978,
EPA-600#-78-051a, March 1978.
Kagawa, T., Quality of the
Environment in Japan—1978, Japan
Environmental Agency Report, December
1978.
24
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United States
Environmental Protection
Agency
RD 681
Official Business
Penalty for Private Use
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