United States
Environmental Protection
Agency
EPA-600/8-80-004
February 1980
Office of Research and Development
Research
Summary

Controlling
Nitrogen Oxides

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Recent research indicates that nitrogen oxides (NOX) could be
one of the most troublesome air pollutants of the 1980's. More
than 20 million metric tons of NOX are annually polluting our
air as a result of the widespread combustion  of fossil fuels in
power plants, industrial boilers, and automobiles and trucks. If
present trends  continue,  nitrogen  oxides  emissions could
grow by 50% over the next twenty years, with the increases
coming primarily from industrial  sources.

Present levels of  NOX emissions  already pose a significant
threat to our health  and  environment. This threat is due not
only to the widespread nature of  combustion sources, but also
to the unusual chemical properties of NOX.  Nitrogen  oxides
are directly harmful  to human health, and are precursors of
photochemical oxidants such as  ozone, the major component
of urban smog. They can also be converted into nitric acid,
one of the two principal  components of acid precipitation.

As the Nation increasingly turns  to coal as a bridge to cleaner
sources of energy, we must recognize that, at current levels of
controls, coal-fired plants emit more nitrogen oxides than gas
and oil-fired plants. Since natural environmental processes are
not able to cope with even current NOX emissions, we must
move rapidly  to improve NOX control technologies for all major
sources.

The  EPA is actively working with other Federal agencies and
the academic, industrial,  and  private research communities to
develop viable combustion technologies which will strictly
limit  NOX emissions.  We  have prepared  this  Research
Summary to  inform  you  of the status of our efforts to make
improved  control technologies available as soon as possible.
                                  Stephen J. Gage
                              Assistant Administrator
                           for Research and Development
This brochure is one of a aeries providing a brief description of major areas of the Environ-
mental Protection Agency's research and development program. Additional copies may be
obtained by writing to:
       Publications
       Center for Environmental Research Information
       US EPA
       Cincinnati, OH 46268

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Increasing
Emissions
                             Each year more than 20 million metric tons of nitrogen oxides
                             (NOX)  are released into the atmosphere as a result of fuel-
                             burning activities in the United States. While fires and other
                             natural occurrences result in about 10 times the amount of
                             NOX generated by man, naturally occurring nitrogen oxides
                             tend to be dispersed over very large areas. NOX produced as a
                             combustion  by-product from  energy-related  technologies
                             developed by man can create local pollutant levels that are
                             10 to 100 times greater than natural concentrations. Nitrogen
                             oxides are emitted from combustion sources primarily as nitric
                             oxide (NO). Atmospheric processes  may  convert the nitric
                             oxide to  nitrogen dioxide (NO,) and nitric acid (HN03).
i _ *j™^  ir™^--™™'""*^^^«™™sl™i»™^«'s^f^w                  if j t
In 1977 nitrogen oxides accounted for approximately12%  of
the total estimated U.S. pollutant emissions of 194 million
metric tons. Nitrogen oxide emissions have steadily increased
in recent years. The EPA's latest air pollution projections indi-
cate an approximately 50 percent increase in NOX emissions to
the year 2000.

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Effects of NOX
Concern over nitrogen oxide emissions is based on known
cases of human health problems and environmental damage
caused by NOX or atmospheric  compounds derived from
NOx  Probably the most important ecological effect of NOX is
its contribution of the formation of photochemical oxidants
commonly known as smog. NOX reacts with hydrocarbons in
the presence of sunlight to form these oxidants.  Ozone w the
main constituent of photochemical oxidants, and can  have
severe effects on the respiratory system. Breathing smog
irritates the lungs and can  seriously aggravate asthma and
other respiratory diseases.  Coughing, eye irritation,  head-
aches, and throat  pain  are commonly experienced during
exposure  to smog.

Exposure to NOX itself is believed to increase the  risks of acute
respiratory disease and susceptibility to chronic respiratory
infection. Nitrogen dioxide (NO,) contributes to heart,  lung,
liver and kidney damage. At high concentrations, this pollu-
tant can be fatal. At lower levels of 25 to 100 parts per million
 it can cause acute bronchitis and  pneumonia. Occasional
 exposure to low levels of NO2 can irritate the eyes and  skin.
  Acid Rain
  Photo Credit: EPA Documatica

  In  addition,  nitrogen oxides are toxic to vegetation. Many
  plants can metabolize low concentrations of NOX. However,
  higher concentrations reduce growth and seed fertility.

  NOv emissions also affect the environment by  contributing
  substantially to the acid rain problem. Through a series of
  complex atmospheric reactions nitrogen oxides  can be  con-
  verted to nitric acid, which may then be deposited in the  form
  of rain or snow. Rainfall tested in various parts of the country
  has become much more acidic over the past 40 years. Nearly
  half of this present acidity is due to nitric acid. Acid rainfall in

  2

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Thermal versus
Fuel NOX
 NOX Sources
the Adirondack  Mountains of New York has reduced or
destroyed commercially and recreationally important species
of fish in at least 90 lakes. Other areas of the United States
such as northern Minnesota and Wisconsin are beginning to
experience similar effects.

Nitric oxide is formed by two chemical processes that occur
during combustion.  In one process the heat of combustion
causes the oxidation of nitrogen in the air. In the other process
it  is the  nitrogen in the fuel which becomes oxidized. The
former process results in what is commonly known as thermal
NOX, and the latter in fuel NOX.  The formation of thermal NOX
is  strongly dependent upon the amount of heat available and
can be controlled by reducing the temperature. The formation
of fuel NOX, on the other hand, is primarily dependent upon
the amount of oxygen available.

One should bear in mind that the ultimate goal of nearly all
nitrogen oxides  control processes is to  either convert the
harmful  oxidized forms of nitrogen (NO, NOj) to harmless
molecular  nitrogen (N2),  or to  prevent the oxidation of
nitrogen in the first place. Molecular nitrogen is a colorless and
odorless  gas that constitutes 78% of  the atmosphere by
volume.
About half of the NOX emissions from fuel combustion come
from stationary  sources such  as furnaces and boilers.  The
other half come  from automobiles and other motor vehicles.

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                            By 1985 stationary sources are estimated to account for 70% of
                            manmade  NOX emissions. Part of the reason for growth in
                            stationary source NOX emissions is the growing trend toward
                            using  coal for electrical generating  stations and industrial
                            boilers. Coal is the most abundant fuel in the U.S., but it also
                            presents  the  most complex  emission  control problems;
                            Because there is more  nitrogen in coal than in most  other
                            fuels,  burning coal  produces  more  NOX than burning oil
                            or gas.

                            Nearly one-third of all NOX emissions are released from elec-
                            trical generating  stations. Another 12 percent come  from
                            industrial furnaces, boilers, and manufacturing processes.
Research
Goals
The  Environmental Protection Agency's  Office of  Research
and  Development (ORD) is developing inexpensive methods
to  reduce  NOX  emissions  from  various  combustion
technologies without causing operating problems, shortening
equipment life,  or increasing emissions of other pollutants.
Most of the ORD research is performed in conjunction with
the Federal Interagency Energy/Environment Research and
Development Program.  More  than  15  agencies perform
research under  this  EPA-sponsored program established  to
ensure a coordinated  and cost-effective approach towards
Federal energy/environmental R&D.

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Reducing
Emissions
The most  promising methods of reducing NOX emissions
currently are:

  Before burning:
    •  fuel denitrogenation

  During burning:
    •  staged combustion
    •  catalytic combustion

  In exhaust gas:
    •  flue gas treatment
    •  catalytic emission control

Prime  responsibility for the development of NOX control
technology lies  with  the  EPA's Industrial  Environmental
Research  Laboratory  in  Research  Triangle  Park,  North
Carolina {IERL-RTP). Additional research is being conducted
at  the  Environmental   Sciences  Research  Laboratory  in
Research Triangle Park  (ESRL-RTP), and through the  Head-
quarters Office of Environmental Engineering and Technology
in Washington, D.C.

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                              EMISSION  CONTROL TECHNOLOGIES
  Fuel
  Denitrogenation
  One approach to reducing nitrogen oxide emissions is to
  remove a large part of the nitrogen contained in fuels. Various
  industries  are  conducting  research  into  methods  of
  denitrogenation,  and  ORD's  Industrial  Environmental
  Research Laboratory in Research  Triangle Park has been
  actively involved in these studies.

  Nitrogen is removed from liquid fuels by mixing the fuel with
  hydrogen gas, heating the mixture, and using a catalyst to
  cause the nitrogen in the fuel and the gaseous hydrogen (H) to
  unite.  This  produces ammonia {NHJ  and  cleaner fuel.
  Researchers are working to discover better catalysts and to
  find ways of reducing the deposition of carbon on the catalyst
  surface. Such deposition  decreases  the efficiency of the
  catalyst.

  This technology can reduce the nitrogen contained in both
  naturally-occurring and synthetic fuels. It  could become a
  particularly important means of controlling NOX  emissions
  from liquid fuels derived from oil shale and coal. Their levels of
  fuel-bound nitrogen  are higher than  the  levels  found  in
  naturally occurring oil.
Staged
Combustion
Staged  combustion  processes  developed at the Industrial
Environmental  Research  Laboratory in  Research Triangle
Park,  North Carolina (IERL-RTP) significantly reduce NOX
emissions. Staged combustion is applicable to a wide range of
fuels and energy facilities including pulverized coal burners
and small-scale industrial boilers.
6

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Pulverized
Coal
Burner
                            In the initial  stage  of combustion, the air supplied  to the
                            burners is (ess than the amount needed to completely burn the
                            fuel. During this stage,  fuel-bound nitrogen is released but
                            cannot be oxidized,  so it forms stable molecules of harmless
                            molecular nitrogen (N2). Other components of the fuel are also
                            released without being fully oxidized. These include carbon
                            particles and carbon monoxide. By adding a second stage of
                            combustion where there  is more air in the fuel-air mixture, the
                            carbon and carbon monoxide can be burned, converting them
                            to carbon dioxide.

                            Modifying existing coat furnaces to achieve a staged combus-
                            tion process has resulted in a 30% to 50%  reduction in NOX
                            emissions. In addition to  reducing NOX emissions, limiting the
                            amount of air during the combustion process increases the
                            efficiency of converting fuel to usable heat.
                                                       ">. -  TV - a, i i,     fl  ^-t- ""j '  i
                                                       -i f_  rt *'  ^J v* * V   K   j,
                                                       r-V%o.^.-r'  'V'V'"^
A  new coal burner design based on  staged  combustion
may reduce NOX by as much as 85 percent. The burner pro-
duces  a fuel-rich  primary combustion  zone and controls
the fuel-air mixing. These conditions lead to preferential con-
version of the nitrogen in the coal to molecular nitrogen (N2).
In  conventional  burners,  this  fuel nitrogen is the  primary
source of NOX. Additional air is introduced from the periphery
of  the burner to complete combustion in a secondary zone.
The design also results in low levels of carbonaceous emissions,
consistent with high energy efficiency.

This burner design has been fired at rates comparable to those
required for boiler application.  The evaluation of  the  perfor-
mance of  the burner in actual field  conditions will be  carried

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Boiler
Corrosion
Prevention
Residential
Oil Furnaces
out on two industrial and two  utility boilers  over the  next
several years.

Before industry invests its money in a new NOX control tech-
nology, it needs assurance that the technology will not have
major operating  problems.  Laboratory engineers are working
with a committee of representatives of electrical utility com-
panies to address potential problems in adapting the staged
combustion technology to  pulverized coal-fired boilers.

A major concern within  the electric utility industry is that the
reduced amount  of air available in the first stage of combustion
may cause the formation of iron sulfide on the  metal surfaces
inside the boiler. Iron sulfide would then progressively corrode
the metal in the walls of the boiler. The Office of Research and
Development has obtained  a utility boiler equipped for staged
combustion, and is measuring the effects of  corrosion  over
several years.
Although the extent of  possible corrosion from staged com-
bustion has not  yet been determined, scientists at IERL-RTP
are already experimenting  with  techniques  to prevent such
corrosion.  In one experiment, some of the metal surfaces in
the boiler have been replaced with  a metal alloy thought to be
corrosion resistant. In another,  air is  forced  into the  boiler
along a metal wall, forming  a curtain  of air. This curtain of
forced air should prevent iron sulfide from being formed.

Conventional oil-fired residential furnaces introduce oil and air
into a firebox where the  burning occurs. This combustion
either heats air or water which is circulated through the house.
A new furnace design has been developed and  is undergoing a
two-year field  evaluation. The  design incorporates several
features  to reduce pollution while increasing fuel efficiency. A
burner has recently  been developed that reduces both NOX
and carbonaceous emissions.
                             Pholo Credit: Rockwell International

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Small-Scale
Industrial
Boileis
Water/Oil
Emulsions
A primary  innovation in the residential oil furnace was  to
remove a controlled amount of heat from the firebox, and thus
reduce the formation of thermal NOX- The field tests have
shown that this newly developed oil-fired residential furnace
has reduced NOX by 65 percent. Oil consumption was also
reduced by an average of 15 percent. Thus fuel savings have
been achieved while simultaneously protecting the environment.

Boilers used for light industry and for heating large buildings
are usually manufactured and  assembled as a unit, prior to
shipment to various users. Typical boilers of this type burn No. 2
or No. 6 fuel oil. The No. 6 fuel oil is a heavy residual product
from  refineries, and about 70% to 80% of the NOX emitted
from burning this fuel is derived from the nitrogen chemically
bound in the oil.

Reducing the  amount of oxygen available during the initial
combustion stage has  been demonstrated  to  be a viable
technique to  reduce  NOX emissions from these boilers. The
reduced amount of oxygen, however,  results in incomplete
combustion so that the amount of carbon particulates emitted
in the exhaust increases.

A project is underway to develop a burner for these boilers
that will limit NOX emissions while maintaining the high effi-
ciency of the boiler and preventing the formation of carbon
particulates. Experiments  are being conducted that will identify
the combustion properties of the several No.  6 fuels on the
market, and provide information on the size and distribution of
droplets being sprayed from the fuel nozzle.

One of the  methods of reducing NOX emissions from oil-fired
combustion systems  is to mix water  with the oil before it is
sprayed into  the  burner. Water decreases the combustion

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                          temperature and can reduce NOX emissions from burning light
                          weight oils by as much as 15%.

                          Studies are being conducted to evaluate the applicability of
                          using water/oil emulsions in  various small-scale industrial
                          boilers and residential furnaces. A significant added advantage
                          in using these emulsions is that they reduce the emission of
                          particulates. When water is mixed into the oil, each oil droplet
                          sprayed into the firebox has several tiny water droplets inside.
                          The heat existing in the firebox makes these water droplets
                          flash into  steam and  explode  the oil droplet. Increasing the
                           surface area of the oil enables it to burn faster and more com-
                           pletely A reduction in particulate emissions can be achieved
                           regardless of whether light oils or heavy oils are being burned.

                           When the amount of  water added to the oil is properly con-
                           trolled  it does not reduce the efficiency of the boiler or furnace.
                           In fact  the  efficiency of a poorly adjusted  burner can be
                           increased slightly by putting up to 18% water in the emulsion.
                           The increased efficiency results from the more complete burning
                           of the oil.
    T  ul                  Gas turbine engines are used primarily to provide additional
Gas Turbine               electrical power during the few hours of each day of h.ghes
E"fl'nes                   demand  Utility boilers that produce most  of our  electrical
                           power require a relatively long period of time to start up. Gas
                           turbine engines can be started and shut  f wn  qu.cWy The
                           enpines usually burn natural  gas or No.  2 fuel oil, both of
                           which have relatively low levels of nitrogen. The pnmary focus
                            of NO  control for gas turbine engines has been to reduce the
                             mnnnt of thermal NOv  generated during combustion. The
                             S dCoach has Seen to inject water into the combus-
                            tion  area, thereby reducing the  burning temperature  and
                             he amount of NOX formed. Unlike adding  water  in an oil-

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Catalytic
Combustion
water emulsion, simply spraying water into the combustion
zone decreases efficiency. Typically, the engines' efficiency is
reduced by 2 percent to 5 percent. Water for injection systems
is in short supply in many arid parts of the country, and where
it is available, it must be purified.

EPA's  Industrial   Environmental  Research  Laboratory  in
Research Triangle Park undertook the task of developing com-
bustion  NOX  controls   without  using  water.   A  major
breakthrough in design  of the gas  turbine engine enabled
them to successfully burn the fuel in a staged combustion pro-
cess. This was accomplished  by  altering the shape  of the
combustion chamber so that the gases coming from the initial
combustion  zone are compressed at the point where addi-
tional  air is added to complete the  combustion. This new
design can reduce uncontrolled NOX emissions from 200 parts
per million (ppm)  to 20 ppm.

Another method  of reducing pollutant emissions  is to use a
catalyst  to achieve oxidation of fuel rather than high  tem-
perature. Experiments  are being  conducted  to develop
catalytic combustion systems for both stationary  gas turbine
engines and small industrial boilers. Natural gas, propane, and
vaporized distillate oil are being used as fuel for the catalytic
combustor.  Fuel  and air are mixed  to the desired ratio and
introduced into a chamber containing the ceramic or metal
catalyst. Various  compounds are being tested to  identify the
most desirable catalysts.

Catalytic  combustors for gas turbines  have reduced  NOX
emissions to well  below 10 ppm. Catalytic combustion is more
                                                         CATALYTIC
                                                        COMBUSTION
                                                        '  CHAMBER

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Ammonia
Injection
well.
Ammonia  is an unoxidized nitrogen-containing compound.
^RLRTP is evaluating a process developed by private industry
 n whtah amenta is injected into a boiler in the post combus-
Iton zone  flle ammonta reacts with the NOX, reducmg it to
harmless molecular nitrogen.
                            Ammonia injection has been experiment-y-»,,U«M ——-
                               12

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Flue Gas
Treatment
Motor
Vehicle
Exhaust
NOX emissions can also be reduced by removing them from
the exhaust gases that are released from burners. There are
two studies currently underway at the Industrial Environmental
Research Laboratory in Research Triangle Park to develop and
test such equipment.

One of these studies  focuses on NOX removal alone and
operates on the same principal as ammonia injection. Am-
monia is added to the flue gas prior to the gas passing over a
catalyst. The catalyst enables the ammonia to react chemically
with the NOX converting it to  molecular nitrogen  (N2) and
water. This system  promises to achieve as high  as 90%
removal of nitrogen oxides from flue gases.

In a second study, a  process is  being developed to remove
both NOX and sulfur oxides (SOXJ. The combustion gases are
moved across a  bed of copper  oxide which reacts  with the
sulfur oxide to form copper sulfate. The copper sulfate acts as
a catalyst for reducing NOX to ammonia. Up to 90% of the
NOX and SOX can be removed from the flue gas through this
process.
Equipment for both kinds of flue gas treatment systems are
being installed at two coal-fired electric power generating stations
as pilot studies. The NOX removal process is being tested  at
the Georgia Power Company's  Plant  Mitchell in  Albany,
Georgia.  The NOX/SOX removal system  is being tested  at
Tampa  Electric Company's  Big  Bend  Station  near North
Ruskin, Florida. This second  project  is  of particular interest
because it is the first test of the technology  in the U.S., and
the first test anywhere in the world on a coal-fired plant.

Currently the most promising technology for reducing NOX
emissions from motor vehicles  is a  special 3-way  catalytic
converter. The catalyst causes nitric oxide (NO) to oxidize
carbon monoxide {CO} and hydrocarbons (HC). In this process,
molecular nitrogen, carbon  dioxide, and water vapor are
released.
                            Photo Credit: Ken Altahular
                             13

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                           In order to make this reaction work efficiently, the proportions
                           of NO, CO, and HC entering the catalytic converter must be
                           carefully controlled. This is done by regulating the ratio of air
                           and fuel in the combustion chamber. Too much fuel results in
                           increased CO and HC emissions. Too much oxygen results in
                           increased emissions of nitrogen oxides. An oxygen sensor in
                           the exhaust manifold allows control, while an active feedback
                           device adjusts the mixture of air and fuel in the carburator or
                           fuel injection system.

                           Tests are being conducted by the Environmental Sciences
                           Research Laboratory  to determine  the  emission  rates  of
                           pollutants from vehicles equipped with 3-way catalytic con-
                           verters. Pollutants being measured include  nitrogen oxides,
                           carbon  monoxide,  hydrocarbons,   ammonia,   hydrogen
                           cyanide, and other toxic compounds. These tests are con-
                           ducted  on  both  properly  and  improperly  tuned vehicles
                           operated under a variety of normal and adverse environmental
                           conditions. The results of the  EPA tests currently underway
                           will contribute  toward  determining whether this  device will
                           need to be modified before being widely marketed.
Auto
Exhaust NOX
Measurement
Hand in  hand with the need to develop emission  control
technology is the need  to  develop accurate methods of
measuring the volume of specific emissions.

A project is underway at the Environmental Sciences Research
Laboratory in Research Triangle Park to develop a method of
measuring the NOX emissions from motor vehicles equipped
14

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                            with 3-way catalytic converters. Conventional methods for
                            measuring NOX are not appropriate and tend to overestimate
                            NOX emissions.

                            A new measurement technique using atomic hydrogen (H) is
                            being developed. Hydrogen atoms  reduce  nitrogen dioxide
                            (NOz) in the exhaust to nitric oxide (NO). This nitric oxide plus
                            any nitric oxide formed by fuel combustion reacts with additional
                            hydrogen atoms in a way which emits a very small amount of
                            light. The tight can be measured as a low level electric current.
                            This technique enables scientists and engineers to accurately
                            measure  the  NOX in vehicular emissions containing other
                            nitrogen compounds.
                            Photo Credit: Ken Altshuler
Jet
Engine NO
Measurement
Most NOX from jet engines is in the form of nitric oxide (NO).
Conventional sampling methods use a probe to capture a
specific volume of emissions, which are then cooled to prevent
continued chemical reaction. Measurements of nitric oxide by
the conventional method are not reliable because they allow
the spontaneous oxidation or reduction of the nitrogen com-
pounds on the surface of the sampling probe.

A   refined  electro-optical   measuring   technique  is being
developed by ESRL-Research  Triangle  Park to accurately
15

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                           measure the nitric oxide from jet engines. This work is being
                           performed in cooperation with NASA, the U.S. Air Force, and
                           the Federal Aviation Administration. The measuring technique
                           makes use of the fact that nitric oxide absorbs ultraviolet light.
                           A beam of this light is shone through the engine's exhaust plume
                           while a spectrometer measures the amount of light absorbed. By
                           calculating the difference between the ultraviolet light absorp-
                           tion which occurs when the engine is running and when it is
                           not  running,  the concentration of  nitrogen oxides  can be
                           calculated.
Glass
Manufacturing
Electro-optical measurement techniques are currently being
used to monitor NO and NO* from stationary sources. Their
application to measuring nitric oxide in jet engine exhaust is
unique and difficult because of the high temperature of the
exhaust gases.  The plume temperature from the stack of a
utility or industrial plant may be about 150°C, but the exhaust
from jet engines may be as much as ten times hotter.

In addition to finding ways to reduce NOX emissions  from
combustion equipment,  ORD laboratories  are  investigating
methods  of  reducing  NOX emissions from manufacturing
processes such as glass-making and nitric acid production.

A project to reduce NOX emissions during the manufacture of
glass is being conducted by  ORD's  Industrial Environmental
Research  Laboratory  in  Cincinnati.  In conventional glass-
making processes, the silicon and other materials for  produc-
ing glass are heated  in  a furnace.  Over 50 percent of  the
energy used to heat the furnace is lost in exhaust gases. Exper-
iments are underway to  alter the furnace design so that  the
16

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Nitric Acid
Production
NOX Transport
 exhaust gas is used to  preheat the raw materials for glass-
 making. Preheating has a number of advantages in the glass-
 making industry. It reduces the amount of fuel needed in the
 furnace, the amount of air drawn  into the combustion pro-
 cess, the temperature required  in the furnace to melt the
 silicon material, and the length of time that the material must
 remain in the furnace. Reductions in fuel use, air intake, and
 combustion temperature have resulted in the decrease of both
 fuel-bound NOX emissions, and thermal NOX emissions. The
 costs that the  glass industry could save by using less fuel are
 an additional incentive to make use of the preheating process.

 About 70% of the nitric acid (HNO3) produced in the U.S. is
 used to manufacture fertilizer. Other uses include the produc-
 tion of  industrial  explosives, separating  gold and  silver,
 pickling steel  and  brass, and photoengraving.  Nitric acid is
 produced by oxidizing ammonia (NH3). The oxidation is never
 totally complete, however, and uncontrolled  emissions from
 nitric acid plants are typically on the order of 1000 to 3000 ppm
 NOX.

 Several NOX control techniques are available and are being used.
 The IERL Branch Laboratory in Edison, New Jersey has been
 developing a  technique called  molecular sieve adsorption.
 NOX is removed by converting NO to NO* and adsorbing the
 N02. This process  results in NOX concentrations of less than
 50 ppm in the emission stream, and the N02 which is collected
 can  be used to produce more nitric acid.

 In the early 1970's scientists at ORD's Environmental Sciences
 Research Laboratory in  Research Triangle Park noticed  that
 measurements of  NOX in  the atmosphere were lower than
 expected. A series of studies were initiated to determine
 whether pollutant nitrogen oxides have a short lifespan, and if
 so,  to identify the factors important in converting NOX to
 other compounds.

 Measurements of  nitrogen oxides,  photochemical oxidants,
 and  specific nitrogen  compounds were made downwind of
 cities where significant amounts of NOX were emitted. These
 cities included St. Louis,  Los  Angeles,  Phoenix, Dayton,
 Columbus,  and Boston.  A small plane equipped with instru-
 ments for continuous monitoring  of the pollutants was flown
 back and forth  downwind of the city monitoring plumes which
 sometimes extended 20 to 30 miles from the pollution source.

These  experiments showed that NOX does have a short
 lifespan relative to other pollutants. It may last 6 to 7 hours or
as long as two days. The rate at which NOX is  converted to
 nitrates, nitric  acid, and other pollutants depends on  such
factors as humidity, temperature and the intensity of sunlight.
                           17

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                           INDIVIDUAL RESEARCH PROJECTS
Industrial
Environmental
Research
Laboratory —
Research
Triangle Park,
North Carolina
Selected  research  projects  performed by  or  through  the
various ORD laboratories or offices are listed below.

   • Environmental  Assessment of Stationary  Source NOX
    Control Technologies
   • Effects of Fuel Properties and Atomization Parameters on
    NOX Control for Heavy Liquid Fuel-Fired Package Boilers
   • Development of Criteria for Extension of Applicability of
    Low-Emission, High-Efficiency Coal Burners
   • Field Testing — Application of Improved Combustion
    Technology to Power Generation Combustion Systems
   • Advanced Combustion Systems for Stationary Gas Tur-
    bine Engines
   • Fundamental Combustion Research Applied to Pollution
    Control
   • Investigation of NOX,  Nitrate  and Sulfate  Formation in
    Laboratory Flames
   • Development of Catalyst and System Design Criteria for
    Catalytic  Combustors with  Application  to Stationary
    Sources
   • Evaluation of Fundamental Combustion Phenomena
   • Characterization  of Emission  and Combustion Perfor-
    mance of Alternate Fuels
   • Characterization and Design  Evaluation for Commercial
    Combustion Systems
   • Bench-Scale Evaluation of Simultaneous NOX/SOX Flue
    Gas Treatment Technology
   • Bench-Scale Evaluation of NOX  Flue Gas Treatment
    Technology
   • Effect of Fuel Sulfur on Nitrogen  Oxide  Formation in
    Combustion
   • Miniplant Studies  in  Support  of  the  Fluidized-Bed
    Combustion Program
   • Demetallization of Residual Oils (Phase V — Denitrogena-
    tion Catalyst Evaluation)
   • Experimental and Engineering Support of  the Fluidized-
     Bed Combustion Program
   • Process Automation  Investigations for Environmental
     Process Control
   • Emissions Assessment of  Conventional  Combustion
     Systems
   • Long-Term  Optimum  Performance and Corrosion Tests
     of Combustion Modifications for  Utility Boilers
   • Control  Technology  Application  and Assessment for
     Industrial Stoker Boilers
   • Evaluation of Emissions Control for I.C. Engines
   • Application of Advanced Combustion Modification Tech-
     nology to Industrial Process Equipment
                            18

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Environmental Sciences
Research Laboratory —
Research Triangle
Park, North Carolina
Aerometric Field Study in Vicinity of a Large Power Plant
in Complex Terrain
Aspects of Modeling Urban Air Quality
Design and Fabrication of an Automated Field Monitor
for the Measurement of Atmospheric Nitric Acid
                         19

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Office of
Environmental
Engineering and
Technology -
Washington, D.C.
                            Evaluation  of  the  Accuracy and  Validity of Physico-

                            Chemical Air Quality Models
                            . Kinetic  Study  of  Simulated  SO2,  NOX, RH-Pollutea


                            , Mechanisms of Photochemical Reactions in Urban Air
                             Outdoo  Mutation of Air Pollution Control Strategies
                            .Sharacterization of  Emissions from Prototype  Motor

                             Vehicles Designed for Low NOx Em'^°"snt NO on Pre.
                            • Investigation of the Dependence of Ambient NO, on Pre

                             cursor Emissions

                                                                         Cnen,-
                                                    °< '-rumen*, Techniques for


                                                            issi0nS Usin9 Va.cus


                                             oT^us Emission3 ,rom Stationary

                              Sources bv Remote Sensing
                              Sadies of the Effect of Environmental Variables on the
                              Collection of Atmospheric Nitrate and Development of a
                              Sampling and Analytical Procedure
                              Sopment of a Flashlamp-lnduced Fluorescence Am-

                              bient Air NO* Monitor
        from Combustion Boilers
       ftatat- Air Pollution Monitoring Standard Refer-
ence Materials, Instrumentation and Methods
                             20

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                           FOR FURTHER INFORMATION
Publications
Other Research
Summaries
  NOx Control Review
  A quarterly technical newsletter prepared by EPA's Indus-
  trial Environmental  Research Laboratory in Research
  Triangle Park, North Carolina.
  Individuals interested in receiving the newsletter should
  write to:
   Editor
   NOX Control Review
   US EPA, MD-65
   Research Triangle Park, NC 27711
                             • EPA Research Outlook.  February 1979. EPA-600/9-79-
                               005. 140 Pages.
                               A  concise  description of the  EPA's plans  for future
                               environmental research.
                               EPA Research Highlights. December 1978. EPA-600/9-78-
                               040. 70 Pages.
                               Highlights of the EPA research and development program
                               of 1978.
• EPA/ORD Program Guide. October 1979. EPA-600/9-79-
  038. 85 Pages.

  A guide to the Office of Research and Development—its
  organizational structure, program  managers, and funds
  available  for  contracts,  grants,   and  cooperative
  agreements.

• Energy/Environment  III.  Proceedings  of  the  Third
  National Conference on The Interagency Research and
  Development Program. October 1978. EPA-600/9-78-002.
  386 Pages.

  The proceedings of an annual conference discussing
  energy/environment  issues,  sponsored by the  Federal
  Interagency Energy/Environment Research and Develop-
  ment Program.

• EPA  Research   Summary:  Acid  Rain.  October 1979.
  EPA-600/8-79-028. 23 Pages.

  A brief discussion of what is presently known about the
  acid rain phenomenon and the EPA's  R & D program to
  learn more about the problem.

• EPA  Research   Summary:  Oil  Spills.  February 1979.
  EPA-600/8-79-007. 15 Pages.

  A concise description of EPA's oil  spills R & D program.
                               21

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                               Information on the availability of these publications may
                               be obtained by writing to:

                                 Publications
                                 Center for Environmental Research Information
                                 US EPA
                                 Cincinnati, OH 45268
Technical Reports            • Environmental Assessment  of  Stationary Source NOX
                               Control Technologies: First Annual Report. March 1978.
                               EPA-600/7-78-046.  105 Pages.
                               (PB-279 083, $6.50)	

                              • Control Techniques for  NO  Emissions from  Stationary
                               Sources. AP-65
                               (PB-190 263, $0.70)	

                              • Emission  Characterization of Stationary NO Sources.
                               June 1978. EPA-600/7-78-120A
                               (PB-284 480, $5.25)	
                              • Preliminary Environmental Assessment of  Combustion
                               Modification Techniques:
                                  Volume I.   October 1977. EPA-600/7-77-119a
                                             (PB-276 680,  $6.00)
                                  Volume II.   October 1977. EPA-600/7-77-119b
                                             (PB-276 681,  $16.50)

                              • Proceedings of the Third Stationary Source Combustion
                               Symposium:
                                  Volume I.   Utility, Industrial, Commercial, and Resi-
                                             dential Systems. February 1979.
                                             EPA-600/7-79-050a. 255 Pages.
                                             (PB-292-539, $10.75)
                                  Volume II.   Advanced Processesand Special Topics. Feb-
                                             ruary 1979. EPA-600/7-79-050B. 316 Pages.
                                             {PB-292-540, $11.75)
                                  Volume III.  Stationary Engine and  Industrial Process
                                             Combustion  Systems.  February 1979.
                                             EPA-600/7-79-050C. 177 Pages.
                                             (PB-292-541, $9.00)
                                  Volume IV. Fundamental Combustion Research and
                                             Environmental Assessment. February 1979.
                                             EPA-600/7-79-050d. 234 Pages.
                                             (PB-292-542, $9.50)	

                                Technical Reports may be obtained by writing to:

                                  National Technical Information Service
                                  5285 Port Royal Road
                                  Springfield, VA 22161

                                  or by calling (703) 557-4650
                               22

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Conferences
and Workshops
Questions or Comments
The Office of Research and Development periodically sponsors
various  conferences, workshops  and  seminars to  inform
environmental scientists, engineers,  policy makers, and  the
interested public of  the  latest research and  development
accomplishments. Individuals interested in information about
upcoming conferences should write to:

  ORD Conference  Coordinator
  Center for Environmental Research Information
  US EPA
  26 W. St. Clair
  Cincinnati, OH 45268

The Office of Research and Development invites you to address
any questions or comments regarding the EPA nitrogen oxide
control research program to the appropriate individuals listed
below:
                            Topic

                            Stationary Source
                            Control Technologies
                            Mobile Source
                            Control Technologies
                            Atmospheric Measurement
                            Program Coordination/
                            General Questions
                         Contact

                         Joshua Bowen
                         Industrial Environmental
                         Research Laboratory, MD-65
                         Research Triangle Park, NC 27711

                         Frank Black
                         Environmental Sciences
                         Research Laboratory, MD-46
                         Research Triangle Park, NC 27711

                         William Lonneman
                         Environmental Sciences
                         Research Laboratory, MD-84
                         Research Triangle Park, NC 27711

                         Robert Statnick
                         Office of Research &
                         Development, RD-681
                         US EPA
                         Washington, D.C. 20460
                            23

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  Controlling
  Nitrogen  Oxides
United States
Environmental Protection
Agency, RD-674
Washington, D.C. 20460
Official Business                              Third Class
Penalty for Private use $300                         Bulk Rate

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