United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle, NC, 27711
Research and Development
600/S2-88/013 Apr.1988
&ERA Project Summary
Assessment of SO2 and NOX
Emission Control Technology in
Europe
William Ellison
This report is a compilation of
information on the current status of
abatement technology used to
control major air pollutants, including
sulfur dioxide (S(>2) and nitrogen
oxides (NOX) in Europe. It focuses on
flue gas desulfurization (FGD),
combustion modification (CM), and
selective catalytic reduction (SCR) of
NOX- Information presented was
gathered from utility company
representatives and FGD, CM, and
SCR process developers, as well as
from the author's research. Current
air pollution regulations in Europe,
related problems, operational
parameters of commercial FGO and
SCR plants, FGD and SCR econ-
omics, and the author's evaluation of
the processes are also described.
This Project Summary was
developed by EPA's Air and Energy
Engineering Research Laboratory,
Research Triangle Park, NC, to
announce key findings of the
research project that is fully
documented in a separate report of
the same title (see Project Report
ordering information at back).
Introduction
Updated details are presented of
major FGD and denitrification (de-NOx)
installations in West Germany for coal-
fired boilers. The status of technology in
other European countries is also
presented. The report provides an
understanding of the principal types of
control system designs that have been
applied, outlines technological ad-
vancements that have been achieved,
and reviews operating experience gained
to date in expanded use of FGD and NOX
removal facilities in Europe in the 1980s.
Significant differences from FGD service
and practice in the U. S. and Japan are
described, and specific information that
may improve operation and reliability of
new and retrofit FGD installations in the
U.S. is offered. Principal topics include:
• A presentation of governmental
emission control requirements in
Europe for new and existing coal-
fired sources.
• An overview of West German FGD
and de-NOx installations and pur-
chase commitments, including details
of generic processes applied, op-
erating history and current per-
formance, and trends and devel-
opments m technology utilization.
• Control of industrial boilers.
• Management of solid and liquid waste
by-products
• Substantial activities in other European
countries.
FGD Activity in West Germany
Recent acceleration of European
activities for reduction of SOg and NOX
emissions is centered in the Federal
Republic of Germany (West Germany).
Great emphasis has been placed on
extensive forest damage, considered to
be tied to air pollution, which has
occurred in some regions of the country.
Effects on trees have been particularly
severe in the area of North Rhine-
Westphalia in central Germany, as well
as Baden-Wuerttemberg in the south-
west. In 1983 West Germany enacted a
major national acid rain control directive
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Table 1. Federal SOZ Control Requirements for West German
Coal-Fired Boilers
SC>2 Emission
Limit,
mg/Nm3 (lb/106 Compliance Approx. No.
Size, MW(e) Btu) %Removal Deadline Boilers Existing
Over 110
35 to 110
181035
400 (0.5, avg)
2.000 (2.5, avg)
2,000 (2.5, avg)
85
60
-
07/01: '88
04/01:93
04/01/93
160
370
300
for S02 (see Table 1), spawning a major
program of FGD installation at both new
and existing boilers, primarily on large
coal-fired units. Boilers larger than 110
MW(e) have been required to add stack
gas cleaning by 1988. Reduction of
emissions from smaller boilers, 18 to
1lOMW(e), is tied to a 1993 deadline.
Requirements are the same for existing
oil-fired boilers.
Emission limits for small existing
industrial boilers [e.g., 1% sulfur fuel
fired units larger than about 6,500 Ib/hr
steam generation, the equivalent of about
0.5 MW(e)], are addressed in new
national legislation (TA Luft) of February
27, 1986. With many exceptions at
present, it is specified that boilers
emitting more than 5 kg SCVhr must
limit emissions to 500 mg/Nm3 (180
ppm).
Individual local (provincial) govern-
ments have the authority to impose more
stringent requirements than those
specified by the national laws. For
example, in North Rhine-Westphalia
(with nearly 50% of the electric power
generation of the entire country, a large
portion being fired with lignite) special
requirements were placed on about
3,000 MW(e) of existing lignite fired
boiler capacity in 1984 calling for an
interim SOg emission reduction of
110,000 metric tons per year by 1987
(through temporary low-capital-cost
dry-alkali injection means).
Table 2 shows the number and size of
existing West German boilers, almost all
firing low-medium sulfur fuel, generally
bituminous coal or lignite, and indicates
that more than 150 units are impacted by
the 1988-deadlined SOa-control re-
quirements. Also affected are 7,400
MW(e) of new, coal-burning units under
construction or expected to start up by
about 1990.
Furnaces larger than 110 MW(e) are
fired almost exclusively with hard (bit-
uminous) coal or lignite. The sulfur
content of the hard coal is about 0.7-
1.2% (in the future up to 1.5%); that of
lower quality (ballast) coal, as high as
2.7% sulfur; and that of wet raw lignite,
0.3-1.2%.
In keeping with the 1988 target
compliance date almost all utility units
are now being retrofitted with scrubbers
except for about 12,000 MW(e) of
capacity to be retired by 1993 after no
more than 30,000 additional hours of
operation. More than 100 FGD instal-
lations, primarily commercial-gypsum-
producing types comprising more then
35,000 MW(e), are being erected. About
50,000 MW(e) of FGD is expected to be
in place by the early 1990s. FGD
facilities already running are the result of
a comparatively modest, provincial
control program that began before 1983
and resulted in 20 FGD applications,
almost all for slipstream single-module
installations. Comparatively few boilers
under 110 MW(e) have been retrofitted
with FGD to date. In the absence of a
percent removal stipulation in the 1983
law, boilers smaller than 35 MW(e) may
be expected to typically rely on fuel
modification/switching as needed to meet
the specified 2,000 mg/Nm3 (720 pprr
SC>2 emission limit. Influenced by th
new control activity in Germany, aboi
2,000 MW(e) of usable-gypsum-prc
ducing FGD systems are being installs
in The Netherlands, and a major FG
installation program is underway on utilit
boilers in Austria.
In West Germany, SOa emissions of
million metric tons per year, about 80"!
of which originate from utility an
industrial boilers, are expected to b
reduced by almost two-thirds by 198!
The cost for these FGD installations ha
been projected to be as much as 1
billion (109) German marks (DM). FG
selection in Germany has reflected
strong emphasis on the need to achiev
high system availability (95%). As i
Japan, most of the installations of eac
principal supplier are designed to emplo
forced oxidation to yield a commercial)
usable gypsum and to thus avoid th
substantial cost and complexity c
alternative throwaway-waste manage
ment in Europe.
However, 30 throwaway-waste FGI
systems of 9000 MW(e) capacity ar
being installed, all at minemouth lignite
fired plants where disposal of solid wast
in the mine is anticipated. In mamlan
Europe the use of throwaway-solic
waste processes, including dry or sem
dry scrubbing methods feasible for low
sulfur fuel applications in Scandinavi
and the U.S., is curtailed by the preser
lack of effective means of utilizin
sulfite-containing FGD waste and c
adequate landfill disposal space.
Table 2. Population of Existing West German Coal- and
Oil-Fired Boilers
Size, MW(e) Number Aggregate MW(e) Average MW(e)
Above 300
135-300
75-135
30-75
9-30
41
91
95
378
548
18,400
17,800
9,900
18,500
10,600
450
195
104
49
19
Above 9 (Total) 1153
75,200
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Gypsum-solids dewatering systems
re comparatively simple, typically
comprising primary dewatering by liquid
cyclones, with final dewatering by
centrifuge or horizontal vacuum filter.
Due to transportation-economics some
early installations in Germany use lime in
lieu of limestone. However, as a universal
energy conservation measure, all recent
FGD commitments have been dedicated
to the use of limestone reagent. Rotary
regenerative heat exchangers are being
commonly used to meet the mandatory
72°C (162°F) minimum stack temper-
ature requirement without use of
augmental energy for gas reheat.
Much like a frequent process design
practice in the U.S. during the 1980s, the
most typical FGD system that is
currently being applied in Europe
incorporates:
• Lime or limestone reagent use,
preferably limestone.
• Spray tower absorber design,
rubber-lined.
• In-situ forced oxidation facilities
installed in the sump of the absorber
without use of ^864 reagent for pH
adjustment.
• Production of a throwaway or usable
grade of gypsum.
• Single-loop systems that omit low-
pH prescrubbing used extensively in
Japan and in some early German
installations for segregated removal of
HCI and other minor raw-gas
components.
Use of FGD in West Germany is
comparatively recent, but as of the end
of 1984, almost 3000 MW(e) of
lime/limestone scrubbing systems were
in operation, all of single-module
slipstream design to meet requirements
of pre-1983 legislation. These FGD
system installations are reported to have
provided acceptable reliability and
performance. However, German electric
utility specialists note that, with only
partial scrubbing of plant flue gas, these
earliest installations have not been
subjected to typical full-scale electric-
utility-industry operating conditions
requiring high availability at sustained
high/variable load. Additional FGD
capacity of approximately 5000 MW(e)
originating from the 1983 legislation has
now come on line but is in an initial stage
of operation without an extensive period
of experience. Thus, Germany's massive
FGD program is seen to be at too early a
stage of implementation to show broadly
demonstrated success or to thoroughly
characterize performance and reliability
of system designs that are being applied.
Based on extensive economic
assessments recently published, retrofit
capital investment for a typical 350
MW(e) limestone scrubbing FGD
installation is reported to be 80 million
DM; i.e., 230 DM/kW. Annual cost with
6000 hr/yr of operation is 19.3 million DM
including fixed cost of 14.8 million DM
(representing 18.5% of the capital
investment of 80 million DM). On a unit
basis this annual cost equals 0.92
pfennig (Pfg)/kWh. Values are based on
1985 currency.*
NOX Reduction in West
Germany
After enactment of 1983 landmark
SOg legislation, which imposed modest
NOX requirements, concern about NOX as
a contributor to forest damage
substantially increased. Following a
"technology forcing" provision of the
1983 law tied to state-of-the-art
technical developments, a 1984 accord
between federal and provincial
environmental ministers in effect
substantially reduced the 1983 limits for
NOX. At the same time it called for
deadlines to be set by the individual
provincial jurisdictions. The limit values
legislated in 1983, and tightened by
sanction of the national government in
1984, for coal-fired boilers are shown in
Table 3. Existing coal-fired boilers (with
future operation of unrestricted duration)
as well as new boilers must limit NOX
emission to 200 mg/Nm3, a level
equivalent to about 100 ppm (volume).
(An approximate equivalence between
the four most common emission
concentration measures is: 1 mg/Nm3 =
0.487 ppm = 0.35 g/GJ = 0.000814
lb/106 Btu.) This stringent requirement is
predicated on commercial experience in
Japan indicating that selective catalytic
reduction technology is effective, and the
*1 DM = U S $0 50, 1Pfg per kWh = 5 mills per
kWh
Table 3.
WOX Control Requirements for West German Coal-Fired Boilers
A/Ox Emission Limit, mg NOs/Nm3* (ppm)
( 6% O2 8as/s, Dry Bottom: 5% O2 8as/s, Wet Bottom)
18 to 110 Over 110
Size, MW(e)
New Units, Dry Bottom:
1983
1984
800
400
(400)
(200)
800
200
(400)
(100)
New Units, Wet Bottom (Slag-Tap):
1983 1,800 (900)
1984 400 (200)
Existing Units, Dry Bottom:
1983 1,300 (650)
1984 650 (325)
Existing Units, Wet Bottom (Slag-Tap):
1983 2,000 (1,000)
1984 1,300 (650)
1,800
200
1,300
200
(900)
(100)
(650)
(100)
2,000 (1,000)
200 (100)
"200 mgiNm3 equals about 0.16 lb/106 Btu
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Table 4. Comparison of NOX Emission Standards for Coal-Fired Utility Boilers
A/OX Emission Standard, mg N02INm3 (6% 02)
West Germany, New and Existing over 110 MW(e), (ihravg) 200*
U.S., New Sources 600-750
Japan, after 1987 470
*300 mg/Nm3 for existing boilers.
judgment that it is demonstrated to be
capable of reducing emissions to this low
level. [NOX limits, 1984 basis, for new
oil-fired units are 150 mg/Nm3 above
110 MW(e) and 300 mg/Nm3 from 18 to
110 MW(e). For existing units of
unspecified future lifetime the limits are
150 mg/Nm3 above 110 MW(e) and 450
mg/Nm3 from 18 to 110 MW(e).] Note,
however, that (at the option of boiler
owners, as decided by them in 1984) old
boilers aggregating approximately 12,000
MW(e) capacity will be phased out (i.e.,
retired) no later than 1993 after no more
than 30,000 additional hours of operation,
during which they will be allowed to emit
650 mg N0x/Nm3 (about 325 ppm); for
wet bottom units above 18 MW(e), 1,300
mg/Nm3 will be allowed; and for oil-
fired units, 450 mg/Nm3. The state
government of Baden-Wuerttemberg,
the area of greatest forest-damage
severity, was the first to impose prompt
deadlines for the stringent 1984 NOX
emission limits. Dry bottom boilers, both
new and existing, must comply by 1988;
and wet (molten-ash) bottom boilers, by
1990. Similar deadlines have also been
established by other state jurisdictions
including North Rhine-Westphalia. It is
expected that the retrofitting of NOX
removal systems on existing West
German boilers larger than 110 MW(e)
will be completed by 1990 resulting in an
average 70% reduction in NOX
emissions.
The extremely stringent 200 mg/Nm3
requirement for both new and existing
coal-fired boilers larger than 110 MW(e)
surpasses NOX control requirements in
all other nations including Japan (see
Table 4). The West German NOX
stringency for boilers above 110 MW(e)
is all the more remarkable, considering
that most NOX emissions are from mobile
sources. (Note: additional regulations are
being considered in West Germany that
will require lead-free fuel and catalytic
converters for gasoline-fueled autos.)
Influenced by West Germany, significant
NOX control legislation has also passed
or is pending in Austria, Switzerland, the
Netherlands, Denmark, Sweden, and the
European Economic Community (EEC).
Table 5 shows the NOX emission
management objectives of governing
officials of the EEC, revised in 1985 to
call for emission rates throughout Europe
after 1995 comparable to curren
requirements in West Germany. Ne\
standards in Austria for coal-fire
boilers above 110 MW(e) call for 15
mg/Nm3 for new boilers, and commei
cially developed CM for NOX control ar
expected to be routinely appliec
primarily on dry-bottom boilers
However, the very substantial reductio
that will be required is resulting i
widespread application of SCR t
essentially all German boilers larger tha
110 MW(e). Moreover, since it i
necessary to sustain ample boile
temperatures in wet bottom boiler
sufficient to maintain bottom ash in
molten state, only minor reduction in NC
emission can be achieved by CM; an
wet bottom boilers will require SC
removal efficiencies as high as 90%.
New federal regulations issued o
February 27, 1986, limit NOX emission
from industrial plants with an output <
more than 5 kg NOa/h, generally to
limit of 500 mg/Nm3. (As noted abov(
the S02 emission limit for industri;
plants with an SC-2 output of more than
kg/h has been set nominally at 50
mg/Nm3.)
Table 5.
Effect of Amended European Community Directive
Emission Limits, mg
Coal
Oil
Gas
1983 Proposed Directive
All Plants over 50 MW(e)"
to 1995
after 1995
1985 Amended Directive
to 1995:
after 1995:
over 50 MW(t)
50-100 MW(t)
100-300 MW(t)
over 3QOMW(t)
over
800
800-
800
650
450
220
450
J50
350
180
350
100
50-100 MW(t) 400"~
over iQOMW(t) 200
" 100 MW(t) equals about 37 MW(e).
" J300 mg/Nm3 for slag-tap furnaces.
"•" 800 mg/Nm3 for slag-tap furnaces.
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Table 6. Draft SOg Emission Standards for Fuel Burning Plants in the Netherlands
Fuel flew Installations Existing Installations
Coal Over 300 MW(t):
400 mglm3;
85% efficient FGD
Under 300MW(t):
700 mg/m3
Oil Over 300 MW(t):
400 mg/m3;
85% efficient FGD
Under 300 MW(t).
1,700 mglm3
Gas Refinery Gas: 35 mg m3
Oxygas: 35 mg/m3
Blast Furnace Gas 200 mgim3
Coke Oven Gas: 800 mg/m3
Over 300 MW(t):
0.8% S; and for installations with an indefinite
lifetime, the same as for new installations
Under 300 MW(t):
1.2% S
Over 300 MW(t).
400 mgim3; 85% efficient FGD for installations
with an indefinite lifetime.
Other' 1,700 mg/m3
Under 300 MW(t).
1,700 mg/m3
Refinery Gas: 35 mg,m3
(1;H1986)
Oxygas: 35 mg!m3
(1/1/1987)
Blast Furnace Gas: 200 mg/m3
(1/1/1987)
Coke Oven Gas: 800 mgim3
(1/1/1987)
Other new NOX limits as of February
1986 are
Below 60,000
Nm3/h exhaust
350 mg/Nrr>3
Solids incineration,
less than 50 MW(t); i.e
-Wood
-Fluidized Bed:
Above 20 MW(t)
Other
Oil incineration,
less than 50 MW(t)
Gas incineration,
less than 100 MW(t)
Gas engines
-Diesel
Above 3 MW(t)
Below 3 MW(t)
-Otto
Four-stroke
Two-stroke
Gas Turbines
Above 60,000
Nm3/h exhaust
, 18 MW(e)
50 mg/Nm3
300 mg/Nm3
500mg/Nm3
250 mg/Nm3
200 mg/Nm3
2,000 mg/Nm3
4,000 mg/Nm3
500 mg/Nm3
800 mg/Nm3
300 mg/Nm3
SO2 and NOX Activities in Other
European Countries
The Netherlands
Under pending Dutch law, high-
efficiency FGD is required for all coal-
fired boilers larger than 300 MW(t). Large
retrofitted FGD systems comprising
approximately 2,720 MW(e) at four
power plants are in operation or under
construction, all designed for usable-
gypsum production using wet limestone
FGD for operation with 1.5% sulfur coal
firing. A broad acid rain control regulation
(Tables 6 and 7) modeled after current
West German legislation is currently
being considered, and in the interim has
been used for SC>2 and NOX emission
control guidelines by licensing
authorities.
The NOX emission levels in the draft
emission standards will, even for new
boilers, enable the use of CM and low-
NOX burners to meet NOX control
objectives.
Three tangentially fired coal/natural
gas boilers are under construction. The
boiler volume is increased by 20-25%
compared to the conventional design,
and modified burners with overfire air will
be applied. A 270 g/GJ (about 750 mg
NOg/Nm3) emission limit is guaranteed
by the boiler supplier over a broad range
of coal analyses.
Ten existing oil/natural gas boilers will
be equipped with gas turbines. Exhaust
from the gas turbines will be used as
boiler combustion air. Besides an
increase in boiler efficiency, a con-
siderable reduction of the NOX emission
is expected.
A demonstration of "in-furnace-
reduction" is in preparation for a 185
MW(e) gas/oil-fired boiler. This is seen
as an intermediate step toward
application of this technology for new
coal-fired boilers.
Table 7
Fuel
Coal
Oil
Gas
Draft NOX Emission Standards for Fuel Burning Plants in the Netherlands
New Installations Existing Installations
1/1/1986
Over 300 MW(t):
800 mg/m3
Under 300MW(t):
800 mg/m3
450 mg/m3
350 mglm3
1/1/1988
400 mg/m3
500 mg/m3
300 mg/m3
200 mg/m3
Over 300 MW(t):
Pulverized fired: 1 100-800 mg/m3
Other: 1000 mglm3 (1/1/1989)
Under 300 MW(t):
Not applicable
700/450 mglm3
500/350 mglm3
-------
Finally, a fully government-funded
demonstration of SCR technology for
Dutch coal-fired power plant conditions
is in progress. A 65 MW(e) unit is in
operation. Design NOX removal is 80%,
with a maximum ammonia-leakage of 5
ppm. Technology is by the Japanese
catalyst licensor, Mitsubishi.
Austria
Based on the requirements of the
Ministry of Building and Construction
stated in the Steam Boiler Emissions
Law (DKEG), many FGD and de-NOx
projects are completed or underway.
Through use of FGD, reductions in sulfur
content of fuel oil and diesel oil, and
switching from oil to natural gas fuel,
annual SOa emissions were reduced
between 1980 and 1985 from 354,000 to
180,500 metric tons. Winter season
ground-level air monitoring in the center
of four major cities, including Vienna,
indicates that S02 concentration
decreased from 30 to 60% during this
period. Annual NOX emissions, 65% of
which are from mobile sources, remained
about constant at 216,000 metric tons
during this same period.
The national government drafted a
technology-forcing amendment to
DKEG in March 1986 (see Table 8),
applicable to boilers over 10 MW(t) = 3.7
MW(e), calling for major retrofits to
reduce S02 emissions from existing
units over a 5-year period to levels
already required for new boilers, and to
reduce NOX emissions over a 2-year
period by use of primary (CM) measures.
[Additionally, existing CO emissions
must be reduced to 250 mg/Nm3 (i.e.,
200 ppm), and existing particulate
emissions for boilers above 100 MW(t)
must be reduced to 30 mg/Nm3 (i.e.,
0.025 lb/106 Btu heat input).] Note that
the draft SO2 emission limit for existing
bituminous-coal-fired boilers larger
than 300 MW(t), about equivalent to 110
MW(e), is 150 mg/Nm3 (equivalent to 53
ppm), or 90% SC-2 removal, whichever is
more stringent.
Approximately 2000 MW(e) of wet
FGD is in operation or under
construction, almost all usable-
gypsum-producing lime/limestone
installations, generally equipped with
prescrubbers for segregated collection of
HCI and residual particulate matter.
Retrofit installations include two wet
lime/limestone system totaling 370
MW(e) and one Wellman-Lord system
with scrubber size equivalent to 163
MW(e).
Coal-fired units aggregating 1500
MW(e) have been retrofitted with CM
including overfire air and Iow-N0x
burners under the impetus of DKEG to
reduce NOX emissions. Based on use of
technology by licensees Babcock Hitachi
and Mitsubishi, retrofit SCR installations
designed for 200 mg/NOa/Nm3 outlet
emission were installed in 1986 on three
bituminous-coal-fired units aggregat-
ing 925 MW(e). Additional SCR of 800
MW(e) capacity, primarily by retrofit, is
scheduled for later application (1987 to
1990 initial start-up) in oil- and gas-
fired service. In 1985, SCR pilot plant
operations using technology of licensees
comparative tests of ceramic vs. plate
catalysts for retrofit application in a 330
MW(e) installation scheduled for initial
operation in 1987.
Sweden
Sweden, severely impacted by acid
precipitation for many years, has taken
major steps to reduce its substantial
emissions. Approximately 20,000 lakes
and 90,000 km (56,000 miles) of water
courses are affected by acidification due
to the discharge of SOg and NOX.
Groundwater, land, and forests have also
been affected. At the same time,
between 80 and 90% of sulfurous
precipitation in Sweden comes from
foreign sources. As a result of a national
program, annual SC-2 emissions in
Sweden have decreased by more than
65% from a peak value of close to 1
million metric tons in the early 1970s.
Sweden aims for a reduction by 1995 to
an annual S02 emission inventory of
about 175,000 metric tons or less, a level
65% less than that in 1980. The annual
NOX emission inventory peaked at about
325,000 metric tons in 1980. This
amount is expected to decrease in the
next 10 years due to the introduction of
stricter exhaust emission control
requirements on motor vehicles as well
as measures to restrict NOX emissions
from stationary sources. The aim of the
government is to reduce NOX emissions
by 1995 to a level 30% less than the
1980 peak.
Principal restrictions on new and
existing emissions include a 1% limit on
oil sulfur content and the equivalent
maximum SC>2 emission, 0.24 g S/MJ
(240 g S/GJ), equivalent to 1400 mg
SC>2/Nm3, for use of other fuels.
A 0.2-0.17 g S/MJ (570-970 mg
S02/Nm3) emission-limit guideline
applies to new or modified emission
sources smaller than 400 annual metric
tons sulfur (e.g., industrial boilers, district
heating, and cogeneration plants), the
magnitude of the emission limit varying
with geographic location and other
factors. Several 20-40 MW(t) circulating
fluidized/bed boilers utilize limestone
addition for SC-2 emission control when
firing coal.
An emission-limit guideline of 0.05-
0.1 g S/MJ (i.e., 290-580 mg SO2/Nm3),
equivalent to 0.23 Ib SO2/1Q6 Btu heat
input, applies to emission sources larger
than 400 annual metric tons sulfur. This
has led to installation of dry-scrubbing
FGD for six district steam-heating
plants. As of 1982 two new 500 MW(e)
coal-fired units were anticipated to be in
operation by 1992 (together with 15 to 25
new coal-fired district heating plants in
the size range 150 to 600 MW(t), a few of
which are already in operation with dry-
scrubbing FGD). It is now expected that,
when a new large coal-fired unit has to
be built (to compensate for the expected
permanent shutdown of nuclear power
plants as dictated by national
referendum), government authorities will
require an emission limit both for SC>2
and NOX at least as low as that which
applies in West Germany at that time.
By the end of 1986, an aggregate of
1280 MW(t) [i.e., about 470 MW(e)] of
dry-scrubbing FGD was in operation in
low-sulfur coal service at the six heating
plants noted above. Design removal
efficiencies are generally in the range of
70 to 80% to achieve a 0.1 g S/MJ (570
mg S02/m3) limit value. Most of these
installations include an electrostatic
precipitator precollector, which will help
ensure a maximum potential for utilization
of the FGD solid waste. FGD operations
at two of the plants began in 1982 and
1983 and have been quite good.
In about 1985, concern for NOX
emissions substantially increased, and
the government proposed an NOX
emission limit of 0.1 g NO2/MJ (100
g/GJ), equivalent to 285 mg NC>2/m3
(about 140 ppm), for large existing or
new boilers. Implementation of these
emission regulations for NOX is still being
studied. Also the "bubble concept" is
being considered whereby emission
limits would be tied to the combined
emissions of SC>2 and NOX.
Some commercial experience in NOX
reductions through CM has been gained
at some coal-fired plants in Sweden.
Three 120 MW(t) coal-fired boilers that
began operation in 1982 have com-
paratively large furnaces with tangential
firing and overfire air injection. The NOX
emission is comparatively low, 0.14 g
NC-2/MJ (400 mg/m3). The extra cost is
about 6 Swedish kroner/kW(t); i.e., 16
kronor/kW(e). Similar performance has
been reported at other new pulverized-
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Table 8. Proposed
and NOX Emission Standards for Boilers in Austria
S02 Standard
(90% Removal or mg/m3. below)
MW(t)
10-50
50-100
100-150
150-300
over 300
Lignite
1200
500
350
350
300
Bituminous
400
200
200
200
150
NOX Standard
(mg NO2/m3)
400
300
300
300
150
coal-fired plants. Some retrofitted
facilities include Iow-N0x burners. The
emissions of NOX are in those cases
0.2-0.28 g N02/MJ (570-800 mg/m3).
Information about costs and operating
experience is not yet available.
Denmark
Electric utilities, over an 11-year
period, have converted to 95% use of
coal fuel overall. Four thousand MW(e) of
an overall generating capacity of 8,000
MW(e) will be equipped with 12 FGD
systems by 1995. One 350 MW(e) dry-
scrubbing FGD system under con-
struction will achieve 92% 802 removal
in typical low-sulfur coal service.
Planning for reduction of NOX emission
inventory is underway.
Norway
Because of the wide abundance of
hydroelectric power, there are presently
no fossil-fueled power plants in Norway.
It is possible that one or two 600 MW(e)
gas-fired power plants will be built
within about 10 years. Virtually sulfur-
free gas from the North Sea will be used,
and no FGD will thus be required.
FGD has been installed on industrial
sources such as aluminum smelters,
industrial oil-fired boilers, an ilmenite
prereduction furnace, and tail gas from
Glaus sulfur plants. A large FGD system
is currently being supplied to an oil
refinery catalytic cracking unit. Nearly all
of the FGD systems are Flakt-Hydro
seawater scrubbers aggregating the
equivalent of 1430 MW(e) scrubber
capacity. The control requirements for
such large sources are set case-by-
case in accordance with local re-
quirements. SC>2 emissions from small
industrial boilers, which are located in
urban areas, are limited by burning low
sulfur (1.2%) oil.
Finland
Furnace limestone injection tests have
been carried out, beginning in 1984,
leading to a 1986, full-scale, 250 MW(e)
installation on low-sulfur bituminous
coal service with limestone injected at
the superheating level to avoid furnace
slagging. It is equipped with a 125
MW(e) capacity, direct-contact, flue-
gas humidifier that boosts 803 removal
in gas it treats to 80%.
France
Due to the strong orientation toward
nuclear power development in France,
S02/NOX emission reduction efforts are
understood to be principally directed
toward decreased fossil fuel usage.
In 1985, a parliamentary panel headed
by Minister Valroff published a report
presenting a proposed action plan for
"acid rain" control. Elements of this plan
tied to S02 and NOX control consist of:
• In conjunction with a French
government objective to gam a 50%
reduction in the 1980 SC>2 emission
inventory by 1990, which objective
had already been reached in 1985, an
S02 emission levy of 130 francs per
metric ton of 862 is proposed,
applicable to combustion sources
larger than 50 MW(t) and to non-
combustion sources greater than
2,500 metric tons of 862 per year, to
help fund investments aimed at 862
emission reduction as well as related
process development studies. Special
emphasis for such funding goes to
fluidized-bed combustion and to
other processes allowing desulfur-
ization.
• Implementation of "special protection
zone" and "alarm zone" systems for
specific areas, particularly the city of
Strasbourg.
• Limiting of sulfur content of diesel fuel
and distillate heating oil to 0.2% in
conjunction with such a Europe-wide
measure to be adopted by the EEC.
• Studies of forest dieback.
• A speed limitation on motor vehicles
in conjunction with actions by the
EEC.
Additional related recommendations
include:
• A substantial action plan for reduction
of hydrocarbon emissions to curb
ozone formation considered to be of
significance in forest dieback.
• Flue gas treating for urban waste
incineration to collect HCI.
Belgium
Like France, Belgium emphasizes use
of nuclear power However, although
specific national laws requiring FGD do
not presently exist, it is expected that a
planned 600 MW(e) coal-fired boiler and
an existing 300 MW(e) boiler being
converted from blast furnace gas to coal
will be required to have FGD at efficiency
levels comparable to such system
installations in West Germany
Switzerland
National SO2 regulations are in place
similar to those m West Germany, but
there are no existing coal- or oil-fired
boilers of substantial size.
In Switzerland, as in West Germany,
the spreading decay of the forests is
believed to demonstrate unequivocally
that atmospheric pollution in that country
has reached proportions which seriously
threaten the environment and, hence,
human health.
A detailed overall survey of the
nature/effect of emissions of atmospheric
pollutants m Switzerland (including the
decay of forests) regarding the main
harmful substances - SOg, NOX, and
hydrocarbons (HC) - is being prepared.
There has been a considerable increase
in air pollution in Switzerland since the
1950s. Although 802 emissions have
declined since the beginning of the
1970s, NOX and HC emissions have
continued their upward trend.
Dendrochronological analyses indicate
that the proportion of trees showing
growth disorders has constantly risen
since the 1950s, and forestry experts
believe that, to protect the forests, air
pollution should be brought down to its
1950-1960 level. The Swiss Federal
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Council has adopted a series of
measures seeking to accomplish this.
Italy
In conjunction with extensive coal
energy development in Italy, major FGD
activity is foreseen by U.S. system
suppliers. A new, cooperative, coal-
logistics-related activity by the gov-
ernment of Italy and the U.S. Department
of Energy (DOE) examines the present
and future fuel requirements of Italian
utilities and industries and the capability
of meeting the requirements with U.S.
coal. The U.S. DOE said that Italy is
converting many of its older power
stations to coal and building new power
plants. Because of that, Italy could
double its current steam coal
consumption by the 1990s. Currently, the
U.S. supplies about 9 million annual
metric tons of coal to Italy, which is
about 40% of the coal used in that
country. While metallurgical coal use will
remain relatively constant, steam coal
demand is expected to increase sharply.
The government-owned national
power company, ENEL, is building 10
MW(e) Wellman-Lord, limestone-
gypsum, and ammonia-scrubbing
demonstration FGD systems in Sardinia
for service in high-sulfur bituminous
coal. A bromine-liquor based re-
generative FGD pilot plant will also be
installed in Sardinia for operation in 1988
or 1989.
ENEL is reported to have recently
announced planning and strategy for use
of wet FGD in coal-fired boiler service
and use of modified burners for NOX
emission control.
Spain
In conjunction with the new
membership of Spain in the EEC, new
stringent regulations for environmental
protection are expected to take effect in
a few years. Current S02 and NOX
control-related technical development
activity in that country includes:
• Assessment in a Basque regional-
government sponsored study of local
dolomite and limestone sources for
potential use in wet and/or dry FGD.
• Coal study work to coordinate FGD
process selection with characteristics
of indigenous fuel.
Current tolerant national regulations
limit S02 emissions from boilers to the
level of 3,000 mg/Nm3 for oil-firing,
2,400 mg/Nm3 for bituminous or
anthracite, and 9,000 mg/Nm3 for lignite,
and there is no significant experience
with FGD. Of the boiler supply, 20% is
solid fuel.
United Kingdom
In 1986, British authorities licensed a
new/large, high-sulfur-coal-fired unit
in North Yorkshire without requiring S02
emission control.
However, two positive developments
are reported:
• The UK-government-owned na-
tional power company, CEGB, in
actively investigating the construction
of two new coal-fired power plants
within the next few years, is fully
expected to utilize SOa controls.
• The national government's
Department of Trade and Industry
recently commissioned a
comprehensive study of available
treatment processes for SOg and NOX
control, a report on which was issued
in 1987.
Reduced NOX emissions in firing of oil
and gas have become a major objective.
The latest requirements are for 100 ppm
NOX on oil and 50 ppm NOX on gas, with
a total particulates limit of 115 mg/Nm3.
In newest jet-atomizing fuel-burner
designs, particulate levels of 50 mg/Nm3
are being achieved while maintaining
efficient oxygen levels, with NOX levels
approximately 150 ppm on oil and 80
ppm on gas for most radiant burners in
standard configuration. By adding
discrete external flue gas recirculation
(FGR) to the burner, these NOX levels
can be brought down to and below the
latest requirements, but extra ductwork
and fans are required for conveying the
flue gas. For this reason burners to
achieve FGR internally by means of
education, thereby eliminating extra
hardware, are being developed. The
development of staged fuel or air burners
is being avoided since it is felt that this
would compromise overall combustion
performance of liquid and gaseous fuel
burners.
Turkey
Three small limestone FGD systems
are being installed in Turkey.
Other Countries
Planning of FGD systems on very
large S02 emission sources in the
German Democratic Republic (East
Germany) and Czechoslovakia has
begun.
A Wellman-Lord FGD system has
been purchased for a power plant in East
Berlin.
In Yugoslavia, investigations an
underway at two coal-fired power plants
to determine the cost of installing FGD.
*U.S.Government Printing Office: 1988 — 548-158/67114
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William Ellison is with Ellison Consultants, Monrovia, MD 21770-9316
Charles B. Sedman is the EPA Project Officer (see below).
The complete report, entitled "Assessment of SO2 and NOX Emission Control
Technology in Europe," (Order No. PB 88-168 992'AS; Cost: $14.95,
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
*i
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6250109 1
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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