United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/S7-90/002 May 1990
&EPA Project Summary
A Low NOX Strategy for
Combusting High Nitrogen
Content Fuels
Ravi K. Srivastava
A multistaged combustion burner
designed for in-furnace NOX control
and high combustion efficiency has
been evaluated for high nitrogen con-
tent fuel and waste incineration
application in a 1.0 MW package
boiler simulator. A low NOX precom-
bustion chamber burner has been
reduced in size by a factor of about
two (from 600-250 ms first-stage
residence time) and coupled with 1)
air staging, resulting in a three-stage
configuration, and 2) natural gas fuel
staging, yielding up to four
stoichiometric zones. Natural gas,
doped with ammonia to yield a 5.8%
fuel nitrogen content, and distillate
fuel oil, doped with pyridine to yield a
2% fuel nitrogen content, were used
to simulate high nitrogen content
fuel/waste mixtures. Minimum NO
emission levels of 160 ppm and 110
ppm (corrected to zero percent O2)
were achieved for the natural gas and
fuel oil tests, respectively. These
results correspond to about 85 per-
cent reduction in NOX emissions
compared to uncontrolled emissions
from a conventional burner mounted
on a 0.7 MW commercial package
boiler. Under the conditions tested,
net chemical destruction of NO via
reburning does not seem to be
evident. This may be due to the
existence of rather low primary NO
concentrations before the application
of reburning. However, a beneficial
dilution caused by reburning, as
applied here, may provide lower NO
emissions (on a ppm or lb/106 Btu
basis) along with no loss in heat
output.
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
The family of nitrogen oxide com-
pounds, including nitric oxide (NO) and
nitrogen dioxide (NO2), is generally
referred to as "NOX." These NOX species
are formed during the combustion of
coal, oil, and natural gas by the reduction
and oxidation of molecular nitrogen (N2)
and nitrogen contained in the fuel. NO2 is
a poisonous gas that the U.S.
Environmental Protection Agency (EPA)
has designated as a criteria pollutant
because of its harmful effects to human
health. In addition, NOX emissions are
known to contribute to the formation of
photochemical oxidants and are precur-
sors, along with sulfur oxides (SOX), of
acid precipitation. Two more areas of
concern are emerging regarding NOX
levels in the atmosphere. First, forest
damage as a result of acid precipitation,
reported to be extensive in the Federal
Republic of Germany, has been linked
with increasing NOX levels. Second,
increasing levels of atmospheric nitrous
oxide (N2O) have been measured, levels
that are predicted to contribute to both a
decline in the abundance of stratospheric
ozone and an increase in climatic
warming. Studies of N2O and NO
concentration in experimental flames and
in flue gases indicate that a correlation
may exist between these two gases
formed in combustion processes.
The EPA estimates that about 20
million tons (18,000 Gg) of NOX are
emitted annually from stationary and
-------
mobile sources in the U.S. Unlike SOX
emissions, NOX emissions are increasing.
Coal- and oil-fired utility and industrial
boilers account for over half of these NOX
emissions.
Only 15 percent of the stationary NOX
sources are regulated by EPA's New
Source Performance Standards (NSPS);
the remainder must be addressed with
retrofit technologies if significant NOX
emission reduction is to be realized.
Another NOX control problem is posed by
the potential of incinerating high nitrogen
content wastes in industrial boilers. While
incineration of these materials would not
constitute a significant increase in the
overall national Nx emission level, indiv-
idual plant emissions may be sufficient to
cause a local NOX problem that would
prevent governmental permitting of on-
site incineration. As thermal destruction is
an attractive alternative to landfill storage
of wastes, the need continues for
developing high efficiency, low NOX
combustion technologies.
Most NOX in stack combustion gas is
NO. Much is known about the
mechanisms of NO formation in flames,
both from molecular nitrogen (source of
thermal NO) and from fuel-bound
nitrogen (source of fuel NO). Thermal NO
can be reduced by decreasing peak
flame temperatures. Fuel NO is very
sensitive to reactant stoichiometry and
fuel-rich conditions promote N2 formation
over NO formation. Laboratory studies
and field test data have established the
importance of fuel NO to the total
emission of NOX from residual fuel oil and
coal flames. Therefore, minimizing NOX
formation in flames typically involves
controlling air and fuel mixing rates to
create fuel-rich reducing zones and
extracting heat to reduce final oxidation
temperatures.
To avoid the need for costly post-
combustion NOX removal, several in-
furnace NOX control strategies have been
developed and applied to boilers. These
include reduced air preheat, load
reduction, low excess air, flue gas
reclrculation, overfire air, deep air
staging, fuel staging (or reburning), and
various Iow-N0x burner systems. While
NOX emissions can be reduced by 20-
80% using these technologies, from
uncontrolled levels exceeding 1,000 ppm
for some high nitrogen content coals, the
application of these combustion modifica-
tions can reduce combustion efficiency
and increase sooting and slagging in the
boiler. These problems are of concern in
the boiler cofiring of fuels and wastes
where high waste destruction efficiencies
and minimal formation of other
incomplete combustion products are of
paramount importance. Furthermore,
practical constraints, such as burner and
boiler sizes, limit the effectiveness of NOX
control by combustion modification.
EPA is currently involved in the
development and field demonstration of
two evolving NOX control technologies:
the precombustion chamber burner and
reburning (fuel staging). These
combustion modification strategies pro-
vide alternatives to expensive post-com-
bustion NOX removal technologies, such
as selective catalytic reduction which is
being utilized extensively in Japan and
West Germany, for achieving low NOX
emissions when firing high nitrogen
content fuels or incinerating highly
nitrated wastes. The goal of this work was
to utilize the precombustion chamber
burner and air or air/fuel staging to
develop a burner that is practical for both
new and retrofit installations and is
capable of burning high nitrogen
fuel/waste streams with low NOX emis-
sions and high combustion efficiency.
Specifically, a NOX emission of less than
0.2 Ib (as NO2)/106 Btu (or about 175
ppm NOX measured dry at zero% O2) for
firing gaseous and liquid fuels doped with
up to 5% nitrogen (by weight) was
targeted (1 lb/106 Btu = 0.43 kg/GJ).
This study was carried out in three
phases. Phase 1 dealt with a fundamental
exploration of post-flame combustion
technology, known as reburning. In this
phase the fundamentals of reburning and
its suitability to combustion applications
were studied in detail. This study lasted
from March 1983 to October 1984.
The burner used during Phase 1 was a
low NOX precombustion chamber burner,
designed and fabricated under an EPA
contract by Energy and Environmental
Research Corporation (EERC), Irvine,
California. The burner proved to be a
useful research tool, though its
practicality was limited because of its
size and cost. As a follow-on of the
reburning work, the burner was reduced
in size from 600 ms to 350 ms first-stage
residence time. Subsequent proof-of-
concept tests involving the reduced size
precombustion chamber low NOX burner
and air or air/fuel staging were carried
out. The proof-of-concept tests in Phase
2 helped to generate the experimental
matrix for Phase 3.
During Phase 3, a vertical downfired
combustor was designed, fabricated, and
installed. It was of a modular design to
allow residence time variations, and was
capable of firing gaseous or liquid fuels. It
had ports for detailed samplings and
variable fuels and air injection locations/
methods. Parametric tests were carried
out using this new burner to rigorously
test and prove the concepts generated irj
Phase 2.
This report covers project activities
between November 1984 and July 1987.
Experimental Approach and
Results
The goal of this study was to minimize
NO formation, with an emission target
175 ppm (dry, at zero percent O2) oil
less, and maintain efficient incineration ofl
surrogate fuel/waste mixtures with up to
percent fuel nitrogen by using
precombustion chamber burner reduced)
in size by about half.
The experimental facility, used inl
Phase 1 and shown schematically inl
Figure 1a, consists of a precombustionl
chamber low-NOx burner and a packagel
boiler simulator. The precombustionl
chamber burner consists of a primary!
and air injection module, two 0.91 m long!
spool modules with 0.51 m internal!
diameter, and a 0.33 m long convergent!
module. These burner modules have a!
thick refractory wall lining to minimize!
heat loss, maintaining the high tempera-1
tures that promote conversion of fuel!
nitrogen to N2 under fuel-rich stoichio-l
metries. To achieve rapid mixing in the I
precombustion chamber, the primary fuel I
is injected through a divergent nozzle and I
the primary air, which is not preheated, is I
passed through fixed swirl vanes. The
convergent module minimizes back-
mixing of combustion gas and radiation
loss to the boiler. A water-cooled
transition module, 0.25 m internal
diameter, cools the combustion gas
before secondary air addition to minimize
thermal NO generation. Primary fuel
nitrogen is simulated by premixing
ammonia into natural gas or pyridine into
distillate fuel oil prior to primary fuel [
injection.
The pilot-scale boiler simulator is rated
at 0.9 MW thermal input. The boiler's I
radiant section is horizontal, 0.6 m in
diameter, 3.0 m long, and cooled with
Dowtherm G heat transfer fluid.
Combustion gas exits the boiler through a
vertical stack. The boiler's front face has
8 axial ports for addition of staged air.
The research facility was modified as
shown in Figure 1b. The horizontal 2.66
m long precombustion chamber burner
was shortened to 1.75 m by removing
one of the spool sections. This shorter
burner, with a nominal residence time of
350 ms, has all the essential design
features of the long horizontal burner,
which has a nominal residence time of
-------
Primary Air
• '*' \l:'f''-Refractory/-"'
" ' i i
Radial Secondary Air
Primary Fuel
Package Boiler Simulator
Dowtherm Cooled
Stack
Sample
Port
Water Cooled-' *-Axial Secondary Air
(a) Long, Horizontal Burner
Primary Air
Radial Secondary Air
Primary Fuel
Package Boiler Simulator
Dowtherm Cooled
Stack
3 Sample
Port
Wafer Cooled-' '-Axial Secondary Air
(b) Short, Horizontal Burner
Figure 1. Pilot-scale combustion research facility. The package boiler simulator ftas been
fitted with a precombustion chamber burner and air and fuel staging ports.
600 ms. Two of the eight axial air ports
on the boiler front face were modified to
provide ports for staging fuel into the
boiler at an angle of 45°. This design
allows for reburning application from the
boiler front face, with aerodynamic
separation of the fuel-lean and fuel-rich
zones in the boiler. The end plate of the
boiler has been modified to allow the
insertion of a water-cooled boom for deep
staging of air into the boiler.
The experimental facility is designed
for independent control and measurement
of each fuel, fuel dopant, and air stream.
Stack gas speciation is measured by a
continuous emissions monitoring system.
NO and NOX are measured by chemi-
luminescence. Reported in this paper are
NO measurements only, measured on a
dry basis and corrected to zero percent
O2, (spot-check measurements of NOX
indicated that NO emissions accounted
for over 95 percent of the exhaust NOX
emissions).
At a primary burner firing rate of 0.6
MW and a nominal first-stage stoichi-
ometry of 0.7, shortening the precom-
bustion chamber burner by removing one
of the two modules decreased the bulk
combustion gas first-stage residence time
from 600 to 350 ms. In baselines tests
(without reburning), first-stage stoichiom-
etry was varied, with exhaust excess air
held constant at about 15%. Ammonia
was doped into the natural gas fuel
steam, resulting in a fuel nitrogen content
of 0.66% by weight. Figure 2 shows data
for both the short and long burners. The
minimum NO emission was observed at a
first-stage stoichiometry of about 0.7,
consistent with earlier data at a similar
scale. The sharp minimum in the curve
indicates the sensitivity of NO emission to
first-stage stoichiometry. The minimum
NO emission increased from 50-75 to
200-250 ppm in going to the shortened
burner. These ranges represent average
NO emissions achievable given the small
fluctuations in fuel and air flows.
The amount of NH3 dopant was varied
at the optimum first-stage stoichiometry
(0.7) for both the short and long burners.
Figure 3 shows that NO levels in the
short burner are more sensitive to fuel
nitrogen content than those in the long
burner. With no NH3 addition, NO
emission from the short burner was 90
ppm; from the long burner, the NO
emission was 40 ppm. These levels
indicated the thermal NO component of
the NO emission, coming from the
molecular nitrogen (N2) in the air. During
operation with the short burner, a longer
flame was observed in the boiler than
during operation with the long burner,
because combustion of the hydrocarbon
was less advanced at the secondary air
addition location for the short burner.
Consequently, the peak temperatures in
the boiler burnout zone were slightly
higher than for the long burner. With the
addition of NH3 dopant, the long burner
NO emissions increased to 100 ppm, or a
net 60 ppm contribution from the
surrogate fuel nitrogen. The short burner
NO emissions for high NH3 dopant .levels
in the fuel stream approached 250 ppm,
or a 160 ppm net increase due to fuel
nitrogen. The reduced first-stage resid-
ence time resulted in less fuel nitrogen
being reduced to N2 in the fuel-rich
precombustion chamber. As fuel nitrogen
content increased above 2%, the result-
ing increase in NO emissions became
small.
Thus, an effect of halving the burner
size is to increase minimum NO
emissions for high nitrogen fuels from
100-250 ppm. Another effect is to move
some of the flame back into the boiler,
although still much of the heat release
remains in the preburner. With a shorter
flame length in the boiler with the
preburner than with a conventional
burner, reburning, which requires boiler
volume, is an ideal technology for achiev-
ing additional in-furnace NO reduction.
Subsequently, preliminary tests were
performed to evaluate the concept of
natural gas reburning of combustion
gases from a half-sized precombustion
chamber burner. A primary NO level of
260 ppm was maintained by operating
the burner at an off-optimum
stoichiometry of 0.65 to reduce the
amount of fixed nitrogen dopant (NH3)
required to achieve this emission. This
NO level represents the maximum
-------
rooo
900
800
700
* 600
500
400
300
200
TOO
Short Precombustion
Chamber (lower
residence time)
- Long Precombustion
Chamber (higher
residence time)
0.4
0.5
0.6
0.7
0.8
0.9
1.0
First-Stage Stoichiometric Ratio
Figure 2. Influence of first-stage residence time on NO emission for short and long
preburners.
emission of the half-sized burner when
burning fuels with up to a 4% fuel nitro-
gen. Primary flame zone stoichiometry
leaving the preburner was fixed at 1.1.
The locations of staged fuel and air
addition were varied.
Figure 4 shows the effect of reburn fuel
injection location on NO emissions.
Reburning fuel was added at the 107, 30,
and 10 cm axial locations in the boiler.
Burnout air was added at 168 cm. Figure
4 it was observed that slightly lower NO
emissions were achieved injecting the
reburn fuel downstream of the primary
flame. However, even injecting reburn
fuel at the outlet of the precombustion
chamber resulted in significantly reduced
NO emissions. The data suggest that
reburn fuel can be injected at the boiler
front face and still achieve NO emissions
of less than 150 ppm.
Figure 5 shows the effect of burnout air
injection location on exhaust NO levels.
With reburning fuel injected at 30 cm, air
was injected through axial ports on the
boiler front face. The results show only
slightly higher NO emissions than with
deep-staged (168 cm) burnout air. Thus,
injecting burnout air from the boiler front
face results in NO emissions that
approach the 175 ppm level.
Based on the results of the preliminary
tests, a new burner system was designed
and installed so that reburning fuel and
air could both be injected from the boiler
front wall. The new burner, shown in
Figure 6, was made vertical to increase
preburner temperatures by reducing
radiative heat loss to the boiler and by
taking advantage of thermal buoyancy
effects. This vertical burner, with a
nominal residence time of 250 ms, has all
the essential features of the horizontal |
precombustion chamber burner.
A North American (NA) Scotch-type I
package boiler was used to provide
conventional burner results for com-
parison with the multistaged burner]
results. This boiler is a three-pass unit,
with a continuous service rating of 0.3 kg
of steam per second (2,400 Ib/h). Its size
and thermal characteristics are nearly
identical to those of the package boiler |
simulator.
The parameters affecting the NOX
emissions from the facility with unstaged
controls were fuel nitrogen content,
combustion gas residence time in the
prechamber, first-stage stoichiometry,
and exhaust stoichiometry. The residence
time of combustion gas in the burner
depended on precombustion chamber
length, load, and stoichiometry. The
nominal load was 0.6 MW and 15%
excess air, respectively. Nominal fuel
nitrogen content for the fuel oil/pyridine
mixture was 2% by weight; for the natural
gas/ammonia fuel the nominal fuel
nitrogen content was 5.8%. Preburner
stoichiometry was optimized for all tests
on this facility.
Burner Stoichiometry Variation
First-stage stoichiometry was varied by
changing the primary air flow. Secondary
radial air was adjusted to maintain 15%
excess air. The results are plotted in
Figure 7. The curves indicate a strong
sensitivity of stack NO to changes in
burner stoichiometry. For the gas tests, a
minimum NO emission of 315 ppm
occurred at a burner stoichiometry of
about 0.78; for the oil tests, a minimum of
190 ppm occurred at 0.65. Thus,
additional combustion modifications were
necessary to meet the program goal of
less than 175 ppm.
The shift in optimum burner
stoichiometry suggests a variation in the
thermal environment in the precombus-
tion chamber. Figure 8, shows burner
temperatures measured by suction
pyrometry. Radiation and conduction
errors are estimated to be less than
30°C. The burner temperatures were
found to be higher for the oil tests; thus,
the shift in optimum stoichiometry.
In tests on the North American boiler, a
NO emission of 1,000 ppm resulted when
firing the 5.8% nitrogen gas fuel at 15%
excess air. A NO emission of 765 ppm
resulted when firing the 2% nitrogen oil
mixture at 15% excess air. Thus, the low
NOX burner reduced NO emissions by
-------
300
250
e
a
-§ 200
o
1
s
.c
750
?00
50
First Stage
Residence Time
350 ms
600 ms
1 2 3
Simulated Primary Fuel Nitrogen, %
Figure 3. Influence of fuel nitrogen content on minimum NO emission for short and long
preburners.
68% for the gas iue\ and by 75% for the
oil mixture.
Fuel Nitrogen Variation
The effect of fuel nitrogen variation is
shown in Figure 9. Exhaust NO level
increased with increasing fuel nitrogen
content in the fuel/waste stream, as
expected, with a much greater sensitivity
observed in the conventional North
American burner tests. These results
demonstrate the precombustion chamber
burner's ability to reduce fuel nitrogen to
molecular nitrogen, even with its reduced
size (250 ms). The full size (600-800 ms)
precombustion chamber burner produces
NO emissions even less sensitive to fuel
nitrogen content.
Reburning Tests
In these tests, the total boiler load was
held constant while fuel was diverted
from the primary injector to two
secondary injectors. In this case, the
staged fuel (undoped natural gas) was
injected into the boiler downstream of the
secondary radial air addition. Thus, a
four-stage combustion process was
established, consisting of a fuel-rich
burner zone and three boiler zones
characteristic of reburning (i.e., fuel-lean,
fuel-rich, fuel-lean). The stoichiometry in
the third stage (SR3, the fuel-rich
reburning zone in the boiler) is critical in
this NOX control process. As already
described, all of the staged air and fuel
flows were injected from the front face of
the boiler at various angles, resulting in
the three boiler stoichiometric zones.
Fuel oil/pyridine and natural gas/
ammonia results are given in Figure 10.
Two second-stage stoichiometries (SR2)
were established: 1.1 and 1.0. The NO
emissions under no staging conditions for
the 5.8% nitrogen gaseous fuel firing and
2.0% nitrogen liquid fuel firing were 315
and 190 ppm, respectively. With 35%
fuel staging and 5.8% nitrogen gaseous
fuel firing, the NO emissions decreased
to 195 ppm at a SR2 of 1.1 (and a SR3 of
0.72) and to 160 ppm at a SR2 of 1.0
(and a SR3 of 0.65). Again, with 35% fuel
staging and 2.0% nitrogen liquid fuel
firing, the NO emissions decreased to
120 ppm at a SR2 of 1.1 (and a SR3 of
0.76) and to 110 ppm at a SR2 of 1.0
(and a SR3 of 0.69). Due to less distinct
stoichiometric zones than typically
established in reburning application, the
decrease in NO levels by fuel staging
was not quite as great as that obtained
when the staged fuel was injected farther
downstream of the fuel-lean primary
combustion zone; however, the
configuration used in these tests requires
no boiler penetrations. In addition,
complete destruction of the primary
fuel/waste stream appears to be ensured
by providing all of the required primary
combustion air prior to entry into the
boiler.
Discussion and Conclusions
The combination of shortened
precombustion chamber burner and
reburning met the program goal of
attaining an NO emission of about 175
ppm from firing gaseous and liquid fuels
doped with up to 5% nitrogen. For
reburning (as applied here), the net
decrease in NO emissions seems to be
predominantly due to a dilution of
primary combustion gases by secondary
combustion gases. This can be seen in
Table 1 where NO concentrations
obtained after adding appropriate dilution
to base NO concentrations are very close
to those obtained during corresponding
reburning applications. Thus, net
chemical destruction of NO during
reburning under these experimental
conditions does not seem to be evident.
This may be because of the existence of
rather low primary NO concentrations
before applying reburning. However, a
beneficial dilution caused by reburning,
as applied here, may provide lower NO
emissions (on a ppm or lb/106 Btu basis)
along with no loss in heat output. This
beneficial dilution aspect of reburning
application can be seen by comparing
Figures 9 and 10. Substituting 35% of a
5.8% nitrogen gaseous fuel with a
nitrogen-free one would yield a primary
nitrogen content of 3.77%, and from
Figure 9, firing this fuel would result in
about 290 ppm NO. However, for
reburning, NO emission can be as low as
160 ppm.
-------
Burnout Air
Primary
Fuel and Air
300
250
6 200
150
100
50
Reburning
Fuel (#1)
Reburn Fuel
Injection Location:
10 cm C#3;
0.7
0.8
0.9
SRR
1.0
1.1
Figure 4. NO emissions as a function of reburn zone stoichiometry for various reburn
fuel Injection locations.
-------
Seconda/yA'r #2 Reburning Fuel
Primary
Fuel and-
Air
300
250
200
O
S?
150
100
50
Burnout Air
Burnout Air Injection
Location:
0 cm (#2)
0.7 0.8 0.9 1.0
1.1
Figure 5. NO emissions as a function of reburn zone stoichiometry for various burnout air
injection locations.
-------
Primary Fuel
* Primary Air f
T"^L^ | Radial Secondary Air \
Burner
Staged —
Fuel
i 1
> [CoTI '
:* P,---'M
Boiler Staged Fuel / ,
t^s
*
+
=,
S
N*" "i
F?£r n T
^^MrT
l^-HHj-^ |
Axial Stc
t*-
iged A'r Deeo staved Air -
Ki
Figure 6. Pilot-scale combustion facility including a
vertical precombustion chamber burner.
o
ro
i
1000
900
800
700
600
500
400
300
200
100
Oil
(2% N)
Gas
(2% N)
0.4 0.5 0.6 0.7 0.8 0.9
First-Stage Stoichiometric Ratio
1.0
Figure 7. Effect of burner stoichiometry. Shown are results from tests firing 2.0%
and 5.8% nitrogen gas fuel and a 2.0% nitrogen distillate fuel oil/pyridine
mixture.
-------
2300
2200
2TOO
2000
3
g 7900
-------
325
300 -
250 -
200 -
750 -
100
Primary Fuel
Primary Air
Radial Secondary Air
Boiler Staged Fuel
E
Axial Staged Air
10 20 30 40
Percent Fuel Staging
Figure 10. Boiler fuel staging results. Shown are results from firing a 5.8% nitrogen gas fuel and a 2.0% nitrogen oil mixture.
10
-------
Table 1. Dilution Corrections
Configuration
Waste Load %
Fuel
No. 2 Fuel Oil/Pyridine (2% N)
Natural Gas/Ammonia (2% N)
Natural Gas/Ammonia (5.8% N)
Two Stage
100
190
185
315
65
135
130
260
Dilution Added -h
To Two Stage Reburn
65 65
(SR2 = 1.0)
88* 110
-
169" 160
Air Staging
100
Axial
150
-
220
100
Deep
130
—
160
"Calculations showing addition of dilution:
Natural gas/ammonia (5.8%N): 0.65 x 260 ppm = 169 ppm
No. 2 fuel oil/pyridine (2.0 %N): 0.65 x 135 ppm = 88 ppm
R.K.Srivastava is with Acurex Corporation .Research Triangle Park,NC 27709
James A. Mulholland is the EPA Project Officer (see below).
The complete report, entitled "A Low NOX Strategy for Combusting High
Nitrogen Content Fuels," (Order No. PB 90-155 6641 AS; Cost: $17.00
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
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
11
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