United States
Environmental
Protection Agency
Industrial
Environmental
Research Laboratory-RTF
Combustion
Research
Branch
EPA-600/8-77-O19
December 1977
-------
-------
Power
steelma
Big recipn
engines use
generate power
furnaces.
ustnal processes like
etining. Gas turbines.
:ernal combustion
mp natural gas and
/ommercial and home
All of these ar^^^^pry sources of
pollution. Thafl j^Es noticeable to
most of us as« sources of
pollution as thJPHIind trucks we see
on the street^vQ^M^. But stationary
rces are a major cause of every one
e six air pollutants identified by the
ronmental Protection Agency (EPA)
s having "potentiaf for wide-spread
adverse effects on human health
and welfare."
And we are. At the Industrial Environ-
mental Research Laboratory (IERL) in
Research Triangle Park, North Carolina -
part of EPA's Office of Research and
Development -- a coordinated series of
programs is under way to find the most
effective and economical ways of con-
trolling pollution from stationary sources.
33.7397
PHOTOCHEMICAL
OXIDANTS (SMOG)
ARE NOT EMITTED
DIRECTLY INTO
THE AIR, BUT ARE
PRODUCED BY THE
REACTION OF
NITROGEN OXIDES
AND HYDRO-
CARBONS IN THE
ATMOSPHERE.
Like other branches of IERL-RTP, CRB
supports EPA's Office of Air Quality
Planning and Standards by supplying the
technical information for setting realistic,
attainable standards for pollutant emissions
from stationary sources.
But CRB's job doesn't stop there. By
finding cost-effective ways of controlling
pollution, CRB is helping utilities and
industries meet national air quality stan-
dards so that our air will be fit to breathe -
now and in the coming decades. And by
finding more efficient ways of burning fuel -
particularly coal -- CRB is making an
important contribution to conserving our
nation's supplies of fossil fuels.
It's a big job. There are over 20,000
major stationary sources of pollution in the
United States. And more are being built
every year to satisfy our country's demand
for electricity and industrial products. But
it's a job that must be done if we are to
have the kind of life we want for ourselves
and our children. And it's a job that can
be done -- with support from all of us
ESTIMATED ANNUAL AIR POLLUTION FROM STATIONARY SOURCES - MILLIONS OF TONS
Much of this pollution -- especially
nitrogen oxides, sulfur oxides, and par-
ticulates -- comes from fossil fuel
combustion - - the burning of coal, oil, and
natural gas. Because of the growing
shortage of oil and natural gas, more and
more power plants and industries are
switching to coal, a much dirtier fuel that
produces more of every major pollutant.
This means that pollution from stationary
sources will get worse in the coming
decades unless we do something about it
now.
Within IERL-RTP, the Combustion Re-
search Branch (CRB) is playing a vital
part in this effort to improve the quality of
our air in economically feasible ways. The
focus of CRB's programs is on reducing
emissions of nitrogen oxides, one of the
most harmful pollutants produced by
stationary combustion sources.
-------
Today, almost 24 million tons of nitric
oxide and nitrogen dioxide (NOX) are
emitted into our atmosphere every year
from man-made sources. About 55 percent
comes from stationary sources -- mainly
boilers, furnaces, reciprocating internal
combustion engines, and gas turbines.
Most of the remaining 45 percent is
emitted m the exhaust of highway vehicles.
Most NOX is emitted from combustion
sources as nitric oxide (NO). Once in the
atmosphere, much of this nitric oxide
converts to nitrogen dioxide (NO2) -
pollutant with very dangerous effects on
human health
High concentrations of nitrogen dioxide
have been fatal to miners, firemen, and
other workers. Even at levels as low as 1
part in 1 million, nitrogen dioxide is known
to be a cause of respiratory diseases like
bronchitis and pneumonia -- especially in
children and older people. Recent studies
have also linked low concentrations of
NOX with ozone depletion and high-nitrate
rains. What's more, NOX is one of the
main components of photochemical smog
that ruins visibility in our cities and irritates
the eyes and lungs of millions of people
every year.
In 1971, EPA set a National Ambient Air
Quality Standard for nitrogen dioxide of 5
parts per hundred million (100 micrograms
per cubic meter of air), annual average.
People exposed to concentrations of N02
above this level run a serious risk of
adverse health effects. Yet in the last few
years, average annual concentrations of
NO2 have exceeded the National Ambient
Air Quality Standard in several of our
largest cities, including Los Angeles,
Chicago, Denver, New York, and Salt Lake
City.
What's more, unless more effective control
techniques are applied nationwide, NOX
emissions are predicted to go even higher
in the next two decades.
One reason is that controlling NOX
emissions from mobile sources has proved
to be more difficult than anyone antici-
pated. In 1970, a national emissions
standard of 04 gram per mile for NOX
from highway vehicles was planned to go
into effect by 1976 But the technology
needed to meet this standard has turned
out to be expensive, and it lowers
efficiency so that most cars get fewer
miles per gallon
To conserve gasoline, EPA relaxed
the NOX emissions standard for mobile
sources to 2.0 grams per mile for the
present. And Congress has agreed
that a standard of 1.0 gram per mile is a
reasonable goal until at least 1983. All of
this means that more NOX will be emitted
from highway
vehicles than
originally
expected.
ESTIMATED INCREASE IN ANNUAL NO, EMISSIONS FROM
STATIONARY AND MOBILE SOURCES WITHOUT MORE
EFFECTIVE NOX CONTROLS — MILLIONS OF TONS
MOBILE
SOURCES
STATIONARY
SOURCES
At the same time, the number of power
plants and industrial combustion sources
in the United States is projected to
increase substantially between now and
the year 2000. Most of these new units
will burn coal -- and hundreds of existing
sources may be forced to switch to coal
as oil and natural gas supplies dwindle.
As a result, NOX emissions from stationary
sources could jump to 70 percent of the
total from man-made sources by 1985.
The conclusion is clear: NOX emissions
from stationary sources are going to have
to be reduced substantially to keep our air
clean in the 1980's and beyond.
-------
To develop the technology we need to
control NOx,IERL-RTP's Combustion Re-
search Branch is attacking NOX pollution
where it starts -- in the combustion
process itself.
Research has shown that NOX emissions
from combustion can be reduced by as
much as 75 percent by "combustion
modification" (lowering the combustion
temperature, limiting the amount of oxygen
available, and regulating the way the fuel
and air mix). Combustion modification
reduces the amount of NOX that forms as
fuel burns. This makes it an economical
and effective way to control NOX com-
pared to other techniques.
To find workable combustion modification
techniques for stationary sources. CRB
begins with fundamental research into the
basic chemical and aerodynamic mech-
anisms involved in combustion. This
research is helping us understand the
factors that cause NOX to form, and how
to control NOX without increasing emis-
sions of other pollutants.
Along with fundamental research, CRB
also sponsors advanced research into new
low-NOx designs for combustion equip-
ment, alternate fuels, and advanced
combustion concepts. The ideas being
generated in this research will make it
possible to reduce pollution dramatically
and burn coal and other fuels more
efficiently 10 to 20 years from now.
The second major component of CRB's
program is pilot-scale testing Here, a
wide variety of combustion modification
techniques has been tried out under
controlled conditions in the laboratory.
The goal is to reduce NOX without
causing operating problems, shortening
equipment life, or increasing emissions of
other pollutants. Any technique that
passes the hurdle of pilot-scale testing
must also make it possible to burn fuel as
efficiently as -- or more efficiently than -
today's equipment.
PROGRAM OVERVIEW
programs are conducted in-house at IERL-
RTP laboratories Others are being carried
out through contracts with private com-
panies, grants to universities, and coop-
erative agreements with the recently
formed Department of Energy (formerly the
Field demonstrations are the last -- and in
many ways the most important -- leg of
CRB's NOX control program. This is
where techniques that look promising in
the laboratory are evaluated on full-scale
equipment to make sure they can do the
job under actual working conditions.
During these demonstrations, emissions of
NOX and other pollutants, as well as fuel
economy, are carefully measured. Any
adverse effects on equipment or operation
are also noted. The result is reliable
control technology that equipment manu-
facturers and users can count on.
In all, CRB has underway more than 30
separate programs to develop effective
and economical ways of controlling NOX
They cover all the major types of
stationary sources in the United States,
from small home furnaces to utility boilers
that stand 10 stories high. Some of these
DEMONSTRATED7COST-EFFECTIVE
COMBUSTION CONTROL TECHNOLOGY
Federal Energy Administration and the
Energy Research and Development
Administration}.
CRB also cooperates with owners and
manufacturers of combustion equipment
Most CRB programs are planned with
input from the combustion equipment
industry. And CRB regularly tests
prototype equipment for industry to deter-
mine the effectiveness of new designs in
reducing emissions of NOX and other
pollutants.
It's a systematic, step-by-step approach to
a complicated technical problem And it's
working.
-------
47,8
These giant boilers are used by utilities
and industries to produce steam for power
generation, manufacturing, and dozens of
other industrial processes. The largest of
them can produce over 10 million pounds
of steam an hour -- or over a million
kilowatts of electricity -- more than
enough energy to supply a city of half a
million people
Without controls, a single coal-fired boiler
may emit up to 120 tons of NOX into the
atmosphere daily. An estimated 6 million
tons of NOX are emitted every year from
utility and large industrial boilers in the
United States — almost half of the NOX
from all stationary sources combined.
Unfortunately, unless emissions standards
for coal-fired boilers are tightened. NOX
emissions from utility and large industrial
boilers will almost certainly increase. The
present standard for large coal-fired boilers
is 0.7 pound of NOX for every 1 million
Btu's of heat produced — compared to 0.3
pound of NOX for oil-fired boilers and 0.2
pound for gas-fired units. Because more
and more utility and industrial boilers will
be burning coal in the years ahead, NOX
emissions from these sources could swell
to 200 percent or more above today's
levels
All this points up the need for a much
more stringent emissions standard for large
coal-fired boilers in the years ahead But
before a tighter standard can be enforced,
better control techniques are needed -
techniques that can reduce NOX without
corroding equipment or causing operating
problems.
That's why improving existing control
techniques -- and developing new control
techniques -- for coal-fired utility and
industrial boilers is CRB's highest priority.
To improve current combustion modifica-
tion techniques, CRB is conducting field
demonstrations of full-scale coal-fired
boilers with the cooperation of boiler
manufacturers These tests have already
shown that properly applied combustion
modification techniques can reduce NOX
emissions by 40 percent to a level well
below the current emissions standard
Although long-term tests are needed to
determine the effects of these techniques
on boiler performance, this is a significant
step toward making coal an environ-
mentally safe fuel for our country to burn
Equally important for the decades ahead
are CRB's pilot-scale tests of advanced
combustion modification techniques for
coal-fired boilers As part of this program.
new burner designs are being developed
that can cut NOX emissions from coal-
fired boilers by as much as 60 to 70
percent. This reduction can be achieved
without wasting fuel, damaging equipment,
or increasing pollutants like carbon par-
ticulates, carbon monoxide, or organics. If
all goes according to schedule, these new
low-NOX burners will be demonstrated in
full-scale boilers by 1980 The results of
these tests will help manufacturers of
these huge boilers build effective NOX
controls into their equipment at the factory,
where it can be done economically.
Along with better combustion modification
techniques to meet today's needs, NOX
controls are also needed for the new fuels
that may be used in the 1980's and
1990's — coal-oil slurries, low-Btu gas
from coal, and waste fuels. CRB's
research will help ensure that these new
energy-saving technologies do not create
more problems than they solve.
-------
Small industrial, commercial, and resi-
dential systems are those that generate up
to 100,000 pounds of steam per hour -
or up to 10,000 kilowatts of electricity,
They are used in dozens of industrial
processes, and they produce steam or hot
water for many commercial operations. In
our homes, they're the boilers and
furnaces that supply steam or hot air for
space heating.
By itself, no single small industrial,
commercial, or residential system produces
much of the total amount of NOX that
pollutes our atmosphere. But since there
are literally millions of these systems in
businesses and homes in the United
States, together they are a major source
of NOX pollution. Today, these systems
emit more than a quarter of the NOX from
stationary sources every year - - over
4 million tons annually.
EPA's Office of Air Quality Planning and
Standards is developing New Source
Performance Standards for small industrial,
commercial, and residential systems. To
help set these standards, CRB is mea-
suring emissions from many different kinds
of boilers and furnaces all across the
country.
At the same time, so that businesses and
homeowners will be able to meet the new
standards, CRB is exploring ways of
reducing NOX emissions without increasing
fuel consumption. Modifying existing small
industrial, commercial, or residential sys-
tems already in operation is usually not as
cost-effective as incorporating NOX con-
trols into new designs. So the main aim
of CRB's work is to spell out guidelines for
designing new equipment.
Pilot-scale tests and field demonstrations
on residual-oil-fired package boilers have
already shown that NOX emissions can be
reduced by as much as 50 percent with
new burner and boiler designs. In
addition, tests on both gas- and oil-fired
boilers have demonstrated that combustion
modification techniques are also very
effective in preventing NOX from forming.
Within the next few years, this new
technology will be available for boiler
manufacturers to draw on in designing
Iow-N0x equipment to replace older units
now in the field.
In related programs, CRB is working to cut
NOX emissions from stoker coal-fired
boilers. Emissions from different types of
coal have been measured, and CRB is
now evaluating the operating problems
involved in switching from eastern high-
sulfur bituminous coal to western low-
sulfur coal.
Also being developed is a new residential
oil furnace that burns fuel much more
efficiently and reduces NOX emissions by
more than 70 percent compared to
furnaces now in use. It uses an
advanced burner and carefully matched
firebox to cut both NOX and particulate
emissions. A preproduction model has
been constructed and is ready to be
tested under normal working conditions
in the field.
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Ox : — ,„._.
Stationary engines include both large
reciprocating internal combustion (1C)
engines and gas turbines. Most of these
engines are used to pump gas and oil
through pipelines or as standby electrical
generators for factories, power stations,
hospitals, and other places where depend-
able power is essential. Thousands of
these engines are in use today across the
country. And even though they burn
relatively clean fuels like natural gas and
distillate oils, they produce 2-1/2 million
tons of NOX every year - - almost 20
percent of the total from stationary
sources.
CRB's program for gas turbines is focusing
on advanced controls like changing the
method of fuel/air mixing and the
configuration of the combustor. The goal
is to reduce NOx emissions by 75 percent
for clean fuels like natural gas and light
oils, as well as for dirtier fuels like heavy
oils. Pilot-scale tests are being performed
on 12 new gas turbine combustor designs
with built-in dry NOX control techniques.
Based on these tests, full-scale models of
the two most effective combustors will be
built and tested in the field The end
result will be guidelines for designing
industrial and utility gas turbines with lower
emissions of NOX. carbon monoxide, and
hydrocarbons.
CRB is also investigating ways to reduce
NOX emissions from large-bore recipro-
cating 1C engines. Both new and retrofit
designs for diesel and spark-fired engines
are being studied. The aim of the
program is to find ways of redesigning the
engine chamber so that NOX emissions
will be substantially lowered without
increasing emissions of carbon monoxide,
hydrocarbons, or carbon particulates. As
with gas turbines, the results of these
studies will be used to design new, more
efficient 1C engines that emit less NOX
and other pollutants.
-------
Cement kilns, woodbark boilers, open-
hearth furnaces, and oil-refining process
heaters are all examples of industrial
process combustion. These sources emit
nearly 400,000 tons of NOX into our air
every year - - or about 3 percent of the
annual total NOX emissions. This is a
small percentage compared to utility and
industrial boilers or stationary engines.
feSlLVstti1* ,»> >
* r . •
rl "^r
Nevertheless, NOX pollution from industrial
process combustion is a serious problem
in some areas of the country where iron
and steel works, oil refineries, or other
heavy industries are concentrated. For
this reason, NOX from industrial process
combustion is one of the targets of CRB's
program.
As yet. no nationwide New Source
Performance Standards have been set for
industrial process combustion -- mainly
because of the thousands of different
types of equipment that fall into this
category. CRB, however, has recently
taken an important first step by measuring
emissions of NOX and other pollutants
from all major industrial process com-
bustion sources, including the iron and
steel, cement, aluminum, and petroleum-
refining industries.
In some of these industries, afterburners
are used to destroy pollutants -- espe-
cially organic compounds -- formed in the
combustion process. However, recent
research has shown that afterburners
sometimes actually create NOX as they
destroy other kinds of pollutants. In a
program begun in 1977, CRB is analyzing
afterburner combustion systems as a first
step toward developing standards for
controlling NOX without creating new
environmental problems.
-------
CRB's programs in fundamental research
focus on the two main factors in the
formation of NOX: combustion chemistry
and combustion aerodynamics. Work in
the chemistry of combustion is answering
basic questions about the chemical reac-
tions that occur when fuels burn, and how
temperature, fuel, and air affect these
reactions. At the same time, research in
the aerodynamics of combustion is exam-
ining the physical conditions in the flame
zone, and how different ways of mixing
fuel and air alter these conditions.
Although the primary purpose of these
studies is to increase knowledge of how
NOX is formed and destroyed, CRB is also
exploring how combustion chemistry and
aerodynamics affect other pollutants,
including sulfur oxides, hydrocarbons,
carbon monoxide, and organics This
research is essential in understanding how
to control NOx without increasing emis-
sions of other pollutants.
Thanks to fundamental research, we have
a much better understanding today of how
fuels burn, and of the intricate ways in
which the formation of one pollutant
affects others This understanding is
already helping solve the practical prob-
lems of modifying the combustion process
to reduce NOX and other pollutants. By
knowing more about how the combustion
process works, CRB has been able to
improve combustion modification tech-
niques and design new, more efficient low-
NOx burners Research into the basic
mechanisms of combustion will continue to
play an essential part in controlling NOX
and other pollutants.
-------
As the need for more efficient ways to
produce energy continues to grow, both
government agencies and private industry
are developing new technologies for
combustion processes. CRB's advanced
combustion research programs ask basic
questions about these new ideas at the
very beginning of development. Will NOX
or other pollutants be formed in the new
process? Can those pollutants be
Controlled economically? How will controls
affect the process7 Will it still operate
efficiently? Can it still be adapted to burn
different kinds of fuels?
Answers to questions like these begin with
theoretical studies. Computer simulations,
mathematical models, and good, hard
thought identify problems with proposed
new technologies, and suggest avenues
that may lead to solutions.
When initial studies like these show that a
new idea has promise, a second stage of
research begins. In this stage, laboratory-
scale experiments are conducted to help
researchers learn more about the basic
principles of the new technology. CRB
recently completed a laboratory-scale test
of methanol (methyl alcohol) as a potential
low-NOx fuel for small boilers and
residential furnaces. Laboratory-scale
investigations of combined-cycle com-
bustion techniques and gas derived from
coal are now underway.
The results of these laboratory-scale
experiments pave the way for the next
stage of advanced combustion research:
pilot-scale studies. CRB's catalytic com-
bustion program is in this important stage
of development. Materials like platinum,
palladium, and cobalt oxide are being
tested in a pilot-scale facility for their
potential as combustion catalysts. By
making it possible to burn fuel much more
efficiently at lower combustion temper-
atures, catalysts can reduce emissions of
NOX, carbon monoxide and hydrocarbons
to very low levels. CRB's pilot-scale tests
have already found one catalyst that cuts
NO* emissions from a variety of fuels by
up to 98 percent.
Decades from now, much of the energy
for homes, businesses, and industries may
come from new technologies like catalytic
combustion -- techniques that are only
ideas today. CRB's work in advanced
combustion research is helping to make
these ideas reality.
-------
Most of CRB's programs zero in on very
specific pollution problems for specific
kinds of combustion equipment. But the
environmental assessment is different. It's
a program designed to put CRB's work in
perspective by considering the larger
environmental and economic questions
raised in controlling pollutants from sta-
tionary combustion sources.
One goal of this environmental assessment
is to evaluate the impact that controlling
NOX from stationary sources will have on
our environment, our economy, and our
supplies of energy. What price will we
have to pay to reduce NOX by 25 per-
cent? By 50 percent? By 75 percent?
How will emission of other pollutants like
particulates, carbon monoxide, or hydro-
carbons be affected9 What level of
control can be achieved without causing
operating difficulties and wasting fuel?
Considering all the ramifications, what is
the optimum level of control for each
major type of equipment9
To get these answers, CRB is sifting
through a tremendous amount of informa-
tion on stationary sources, pollutants,
controls techniques, and environmental
effects. In cases where information is
lacking, field tests are being conducted to
gather data.
A second goal of the environmental
assessment is to establish the combination
of control techniques that will work best in
each of the nation's Air Quality Control
Regions. CRB is conducting systematic
analyses of all factors that affect NOX
pollution in each of these regions -- such
as population, the number and kinds of
stationary and mobile sources, fuels
burned, wind and weather patterns, and
topography. These analyses will help
each Air Quality Control Region set up a
realistic, workable strategy for controlling
emissions of NOX and other pollutants
from sources under its jurisdiction.
CRB's environmental assessment program
is an in-depth, 3-year study. When it's
completed in 1979, our country will be in
a much better position to make intelligent
choices about controlling NOX in the
decades ahead.
-------
CRB's work is generating a tremendous
amount of new information on better ways
to control NOX and other pollutants. To
share this information as widely as
possible, CRB has an active technology
transfer program. Its purpose is to bring
ideas and technical information to owners
and manufacturers of stationary source
combustion equipment, as well as
thousands of people in related industries,
government, and universities.
The field demonstration stage of CRB's
research and development program is one
part of this technology transfer program.
These demonstrations are carried out in
factories and power plants in many
different parts of the country with the
cooperation of owners, operators, and
equipment manufacturers. They provide
an excellent opportunity for people in the
field to get hands-on experience with new
technology as it is being developed.
Along with field demonstrations, CRB also
sponsors symposiums on stationary source
combustion. Representatives from govern-
ment agencies, industry, and universities
come together to exchange ideas and
discuss the problems of controlling NOX
and other pollutants. Papers are pre-
sented about current research sponsored
by CRB, and about the government's
strategy for regulating pollutant emissions
These papers are published in the
proceedings of each symposium, and are
available to the public.
Final reports on CRB's research pro-
grams --as well as guidelines for design
and operation of combustion equipment -
get wide distribution through lERL-RTP's
Technical nformation Service and the
National Technical Information Service. In
addition, the results of these programs are
regularly presented at meetings of profes-
sional societies, such as ASME, APCA, and
AlChE.
CRB also sponsors a technical information
bulletin entitled "NOX Control Review."
Published four times a year, the Review is
one more part of CRB's effort to spread
knowledge of the latest developments in
NOX control technology. It now reaches
more than 2000 readers in government
and industry.
.** 4
-------
CRB has already taken some important
steps toward making our air cleaner and
healthier to breathe. Major accomplish-
ments over the last 2 years include:
• Combustion modification techniques for
coal-fired utility and large industrial
boilers that reduce NOX emissions by
40 to 50 percent with no adverse side
effects.
• Pilot-scale tests of advanced pulverized
coal burners for utility and large
industrial boilers that lower NOX emis-
sions by 70 to 80 percent.
• A residual oil burner for small industrial
boilers that cuts NOX emissions by 65
to 70 percent from heavy oils with high
nitrogen content.
• An oil-fired home furnace that reduces
NOX emissions by 70 percent without
increasing carbon monoxide, hydro-
carbons, or smoke.
• Field tests proving that NOx emissions
from small industrial boilers can be
lowered significantly by combustion
modification techniques and by firing
methanol instead of natural gas or
heavy oils.
• Pilot-scale tests of an advanced
catalytic combustion system capable of
reducing emissions of NOX. carbon
monoxide, and hydrocarbons by as
much as 95 percent.
A great deal has been accomplished -
but there's still a great deal left to do.
Over the next 5 years, CRB will be
working to achieve three main goals. One
of these is to demonstrate that the new
low-NOx pulverized coal burners now
being pilot-tested will perform satisfactorily
on full-scale utility and industrial boilers.
This work is a critical part of reducing
NOx pollution in our air. Large coal-fired
boilers already emit over 30 percent of all
IMOX from stationary sources.
And this figure could jump to over 50 per-
cent by the year 2000 without better
controls. New low-NOx burners should
make it possible to cut NOx emissions
from coal-fired boilers by 60 to
70 percent.
Another of CRB's goals for the next few
years is to significantly improve NOX
control techniques for small industrial and
commercial boilers and furnaces. These
units emit only 7 percent of the NOX from
stationary sources today. But with
switching from oil and natural gas to coal,
this percentage is expected to skyrocket in
the next 10 to 20 years. To save time
and money, combustion modification tech-
niques already developed and tested for
large utility boilers will be adapted to
smaller equipment, especially stoker coal-
fired boilers.
^**
-------
CRB's third goal between now and 1983 is
to demonstrate the long-range effective-
ness of combustion modification tech-
niques by performance tests of a year or
more on coal-fired utility and large
industrial boilers in the field. These tests
should show us how to burn coal more
cleanly and efficiently, without increasing
operating problems such as corrosion,
fouling, and slagging. As a result, many
coal-fired boilers that might have to be
phased out for lack of adequate NOX
controls may be kept in operation. And
oil-fired boilers may be switched to coal
without causing additional pollution
problems.
All three of these programs will play an
essential part in our country's switch from
oil and natural gas to coal. Unless we
have the technology to control NOX and
other pollutants to safe levels, energy
independence can only come at the cost
of a more polluted atmosphere. With
CRB's help, we will be able to take
advantage of our nation's supplies of
coal -- and keep our air clean and
healthy in the years ahead.
Prepared by Aerotherm Division of
Acurex Corporation under EPA contract.
Photos courtesy of Aerotherm Division of
Acurex Corporation; Energy and Environ-
mental Research Corporation; Pratt and
Whitney Aircraft Group; Exxon Research and
Engineering Company; International Flame
Research Foundation; KVB, Inc.; Rocketdyne
Division of Rockwell International; U.S.
Environmental Protection Agency; and
Delaval Turbine Inc.
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