V-/EPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-82-034 Sept. 1982
Project Summary
Environmental Assessment of
Stationary Source NOX
Control Technologies:
Final Report
L. R. Waterland, K. J. Lim, E. B. Higginbotham, R. M. Evans, and H. B. Mason
The five major categories of stationary
sources of oxides of nitrogen (NOX) are
utility boilers, industrial boilers,
internal combustion engines, gas
turbines, and residential heating
systems. These categories, together
with industrial processes and minor
sources, emitted 10.5x 109kg(11.6x
106 tons) of NOx (NO2 basis) in 1977,
approximately equaling the mobile
source loading. Under contract 68-
02-2160, these five source categories
were subjected to a 3-year environ-
mental assessment involving multi-
media source sampling and analysis,
NOx control process engineering, and
NOX air quality/regulatory evaluations.
Field tests were conducted on two
coal-fired utility boilers, an oil-fired
utility boiler, two stoker-coal-fired
industrial boilers, an oil-fired gas
turbine, and an oil-fired residential
heating system. Testing followed the
EPA Level 1 protocol which includes
sampling and analysis for criteria
gaseous pollutants, trace metals,
organics, and trace inorganic species.
Tests conducted before and after
modification for low-NOx operation
generally showed few adverse environ-
mental side effects of NO, control.
Where emissions of some species were
increased by NOX control, the environ-
mental effect was counterbalanced by
the beneficial effects of NOX reduction.
Process engineering studies were
made of NO, controls for the five
source categories for both new and
existing equipment. Capital and opera-
ting costs were estimated for NOX
control to various levels and the asso-
ciated effects on energy, operation,
and other pollutants were noted. Re-
trofit controls are available for most
source categories, but the practical
reduction efficiency is limited by
operational constraints and possible
CO or carbon emissions. For new
equipment, NO, can generally be re-
duced significantly using new designs,
with a minor cost impact and negli-
gible effect on efficiency or CO
emissions.
Air quality analyses were conducted
for several NO2 sensitive areas to
determine which controls may be
needed to meet various existing or
projected NOX regulations. For the
most probable NO« regulatory scena-
rios, retrofit controls will probably be
needed only on larger sources in a few
areas. New source controls will be
needed for a wide variety of source
types and at several areas nationwide.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory. Research Triangle
Park. NC, to announce key findings of
the research project that is fully
documented in a separate report of the
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same title (see Project Report ordering
information at back).
Introduction
In 1975, EPA's Industrial Environ-
mental Research Laboratory at Research
Triangle Park (IERL-RTP) started a major
environmental assessment of energy
systems and industrial processes.
These assessments were to detect and
quantify potential environmental prob-
lems with the systems or processes and
identify potential control measures to
reduce the environmental problems
found. This information was needed by
EPA and other agencies to establish
R&D priorities, to support standards
setting activities by regulatory groups,
and to develop environmentally accept-
able energy systems.
The Combustion Modification Envi-
ronmental Assessment (CMEA) was
started by lERL-RTP's Combustion
Research Branch in June 1976 to
support the overall EA program by
focusing on stationary combustion
sources with combustion modification
techniques to control NOX or other
pollutants amenable to control through
combustion process modification.
The three primary objectives of the
CMEA are to:
Identify important multimedia envi-
ronmental pollutants from station-
ary combustion sources:
Under baseline operation with-
out combustion modification
controls.
And, more importantly, under
controlled operation to suppress
NOX or other pollutants amen-
able to control through combus-
tion process modification.
Develop control application guide-
lines on the economic, energy, and
operational impacts of meeting
prescribed emission levels.
Identify the most cost-effective and
environmentally acceptable NO*
control techniques to achieve and
maintain air quality considering:
Current and anticipated air
quality standards.
Alternate equipment use and
fuel use scenarios to the year
2000.
The effort to achieve the above
objectives resulted in the generation of
20 reports which are listed in Table 1.
The initial effort in the program was a
preliminary environmental assessment.
Reports 1 and 2, in which methodologies
were developed, data were compiled
and evaluated, and program priorities
were set. Source priorities were further
quantified in Reports 4 and 5 which
documented nationwide and regional
NOx inventories and population exposure
models. These priorities were used to
direct the effort for the first 2 years of
the contract as documented in Reports 3
and 6.
The process engineering effort in
support of the second objective is docu-
mented in Reports 7-12 for the five
source categories. These reports contain
source characterizations, evaluations of
available and emerging NOX controls for
new and existing equipment, control
costs, and assessments of effects on
other pollutants of low-NOx operation.
The data for the environmental assess-
ments were taken from the field test
results. Reports 13-19, and from data
from other programs.
Environmental assessment field test-
ing was conducted on the following
equipment: a 180 MW coal-fired utility
boiler (Kingston Unit 6), a 500-M W coal-
fired utility boiler (Crist Unit 7), a 750-
MW oil-fired utility boiler (Moss Landing
Unit 6), a 130,000-kg/hr stoker-coal-
fired industrial boiler (Site A), a 90,000-
kg/hr stoker-coal-fired industrial boiler
(Site B), a 60-MW oil-fired gas turbine
(T.H. Wharton Unit 52), and a Blueray
low-emission oil-fired residential heat-
ing system.
The air quality/regulatory evaluation
supporting the third objective is docu-
mented in Reports 3, 6, and 20.
Additional environmental assessment
field testing, under EPA contract 68-02-
3188, began in January 1980.
Conclusions
Analytical results from the seven field
tests were evaluated to identify differ-
ences in pollutant species composition
and levels of concentration between
waste streams (e.g., flue gas vs. ash
streams), between sources and fuels,
and between uncontrolled and control-
led (for NOx) operation. Field test results
indicate that:
For the sources tested, the flue gas
stream presents the greatest po-
tential environmental concern.
NOX and SO2 appear to be the most
important flue gas pollutants.
Overall flue gas pollutant composi-
tion is improved or, at worst, not
adversely affected upon applying
the combustion modifications
tested; changes in emissions of
other pollutants due to day-to-day
fuel composition changes are often
of greater magnitude than those
attributable to NO, control.
The multimedia waste streams
from the sources tested are not
mutagenic; in general, elicit non-
detectable toxicity in bioassay test-
ing, and the limited data for com-
bustion modifications showed
minimal effect on polycyclicorganic
matter (POM) levels.
The combustion modifications
tested:
Have no effect on, or increase
only slightly, emissions of CO
and vapor-phase hydrocarbon.
Have no effect on paniculate
mass emissions.
Have no effect on, or tend to
increase slightly, emitted particle
size distribution.
Have no measurable effect on
trace element emissions or on
trace element size partitioning
tendencies.
Have no effect on, or decrease
slightly, S03 and particulate
sulfate emissions.
Have little effect on total higher
molecular weight organic emis-
sions.
Marginally increase polycyclic
organic matter (POM) emissions,
but the emission levels remain-
ed on the order of the detection
levels of the instrument.
Emissions of the organic priority
pollutants were below the detection
limit for the sources tested.
It must be emphasized, though, that
the sources were tested only under
steady operation, in short duration tests,
and that the controls tested were the
currently available combustion modifi-
cation technologies. Conclusions on the
effects of advanced combustion modifi-
cation controls, and on the potential
effects on pollutants of combustion
sources under unsteady or transient
operation must await results from sub-
sequent test programs.
Results from the air quality/regulatory
analyses were evaluated to identify
research and development priorities for
combustion modification control of emis-
sions of NOx and other pollutants. High
ranking source control priorities include:
Further control of coal-fired utility
and large industrial boilers to the
60 ng/J level through the contin-
uation and success of ongoing
programs.
Further control of large 1C engines,
both spark and compression igni-
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Table 1.
Report
No.
1, 2
3
4, 5
6
7. 8
9
10
11
12
13
14
15
16
17
18
19
20
Summary of Documentation: Contract 68-02-2160
Title
Preliminary Environmental Assessment
of Combustion Modification Techniques:
Volume 1. Summary; Volume II. Technical
Results
Environmental Assessment of Stationary
Source NO* Control Technologies First
Annual Report
Emission Characterization of Stationary
NO* Sources: Volume 1. Results;
Volume II. Data Supplement
Environmental Assessment of Stationary
Source NO* Control Technologies
Second Annual Report
Environmental Assessment of Utility
Boiler Combustion Modification NO*
Controls: Volume 1. Technical Results;
Volume 2. Appendices
Combustion Modification Controls for
Stationary Gas Turbines: Volume 1.
Environmental Assessment
Combustion Modification Controls for
Residential and Commercial Heating
Systems: Volume 1. Environmental
Assessment
Industrial Boiler Combustion
Modification NO* Controls:
Volume 1. Environmental
Assessment
Environmental Assessment of Combustion
Modification Controls for Stationary
Internal Combustion Engines
Combustion Modification NO* Controls
for Utility Boilers: Volume 1.
Tangential Coal-Fired Unit Field Test
Combustion Modification NO* Controls for
Utility Boilers: Volume II. Pulverized-
Coal Wall-Fired Unit Field Test
Combustion Modification NO* Controls
for Utility Boilers: Volume III.
Residual-Oil Wall-Fired Unit Field Test
Combustion Modification Controls for Station-
ary Gas Turbines: Volume II. Utility Unit
Field Test
Combustion Modification Controls for
Residential and Commercial Heating
Systems: Volume II. Oil-Fired Residen-
tial Furnace Field Test
Industrial Boiler Combustion
Modification NO* Controls:
Volume II. Stoker-Coal-Fired Boiler
Field Test Site A
Industrial Boiler Combustion
Modification NO* Controls:
Volume III. Stoker-Coal-Fired
Boiler Field Test Site B
Environmental Assessment of
Stationary Source NO* Control
Technologies Final Report
Date
October 1977
October 1977
March 1978
June 1978
August 1978
June 1979
April 1980
July 1981
July 1981
July 1981
July 1981
July 1981
July 1981
July 1981
July 1981
July 1981
July 1981
July 1981
May 1982
EPA Report
No. (EPA-j
600/7-77 -11 9a
600/7-77-1 19b
600/7-78-046
600/7-78-1 20a
600/7-78-1 20b
600/7-79-147
600/7-80-075a
600/7-80-075b
600/7-8 1 -122a
600/7-8 1-1 23 a
600/7-8 1-1 26a
600/7-81-127
600/7-81-124a
600/7-81 -124b
600/7-81 -124c
6OO/7-81-122b
600/7-81 -123b
600/7-81 -126b
600/7-81 -126c
60O/7-82-034
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tion, through the continuation of
ongoing programs.
Control techniques for industrial
process combustion (particularly
glass melting furnaces, cement
kilns, and refinery process heaters)
through the continuation of ongo-
ing programs.
Pollutant priorities were evaluated by
comparing waste stream concentrations
to target concentrations used for pollu-
tant prioritization in this environmental
assessment study. Higher priority flue
gas stream pollutants include vapor-
phase S03 and condensed sulfate,
organic acids, and trace elements such
as As, Be, Cd, and V. Higher priority ash
stream pollutants from coal-fired
sources are the trace elements Fe, Mn,
Cr, Ni, Be, Ba, Pb, and occasionally As,
Se, Tl, and Sn.
Results
Detailed test results from the program
are documented in the field test and
environmental assessment reports
listed in Table 1.
Test results indicate that SO2 and NO,
emissions are probably the most im-
portant pollutants from all the combus-
tion sources tested. These emissions
are especially high from coal-fired
sources. Other high priority species in
most tests include CO, As, and S03
(vapor phase). The only organic emis-
sions of potential significance noted
were those of carboxylic acids. Several
other trace element species and con-
densed sulfate were flagged in several
tests, although these were not universal-
ly noted.
The highest priority species in the ash
streams from coal-fired sources were
Fe and Mn, followed by Cr, Ni, Be, and
Ba. Interestingly, Pb levels were high
only in particle collector ash streams,
particularly the electrostatic precipitator
(ESP) hopper ash, suggesting that Pb
partitions to more concentrated levels
on passage through a boiler.
In general, changes in the overall flue
gas pollutant composition due to N0»
control are less significant than those
resulting from day-to-day variations in
fuel composition (especially sulfur).
When fuel variations are accounted for,
NOx control application either reduces
key flue gas pollutant levels, or (at worst)
does not adversely affect them.
Since few data existed on the effects
of NOx control on combustion source
polycyclic organic matter (POM) and
other organic emissions, and since
several species in this pollutant class
are quite genotoxic, priority was given to
obtaining data on these emissions in the
field test program.
Table 2 shows total sampling train
organic determination data for the tests
performed. Infrared analysis of sample
extracts showed the organic species in
the samples were in the aliphatic hydro-
carbon, ether, ester, aromatic, and
carboxylic acid categories. The data in
the table indicate that emission of these
higher molecular weight organics re-
mains relatively unchanged with NOx
control application, as is the case also
for CO and HC emissions. The seemingly
high levels of organic compound emis-
sions in the Blueray residential furnace
test are primarily unburnedfuel oil. This
was a result of the on/off cycling of the
furnace during the test.
Additional organic analyses were
made with gas chromatography/mass
spectrometry (GC/MS) speciation of at
least 11 POM species and several other
organic priority pollutants. Results
showed that there is a marginal increase
in POM emissions with NOx control
application. The emission levels were
generally of the order of the detection
level of the instrument. In the analyses
for the organic priority pollutants, none
of these species were found within the
detection limits.
Bioassay testing was performed on
samples taken during the Crist Unit 7,
Moss Landing Unit 6, Site B, and gas
turbine lowest NOX tests. Table 3 sum-
marizes results from all the bioassay
tests performed. The data in the table
show that discharge streams tested had
nondetectable mutagenicity and nonde-
tectable-to-low toxicity.
Table 2. Effects of Controls Tested on Flue Gas Organic Emissions
Organic Emissions (mg/dscm)
Test
Kingston Unit 6
Crist Unit 7
Moss Landing Unit 6
Site A
Site B
T.H. Wharton Unit 52
Blueray Furnace
Control"
BOOS
BOOS
FGR. BOOS/FGR
OFA
LEA
Wl
New design
Intermediate
Baseline /V0X
0.724
4.23
4.38
1.00
0.924
1.30
2.320
7.37
Low /VOx
0.534
0.722
1.43
1.79
1.37
1.10
26.3
aBOOS: Burners out of service; FGR: Flue gas recirculation;
OFA: High overfire air; LEA: Low excess air;
Wl: Water injection.
Source not tested under this condition.
Table 3. Bioassay Test Data with Low NO* Combustion Modifications
Bioassay Result"
Test/Sample
Cytotoxicity Rodent
Microbial Acute Freshwater Freshwater
Control Mutagenesis RAM WI-38 Toxicity Algae Fish
Crist Unit 7 BOOS
>3 urn fly ash 1 Neg ND
<3 iim fly ash j Neg L
Bottom ash Neg ND ND ND ND
KSP hopper ash Neg ND ND ND ND
Moss Landing Unit 6 BOOS/
XAD-2 extract FGR Neg M
Site B LEA
Bottom ash Neg ND ND ND ND
KSP hopper ash Neg L ND
Gas Turbine Wl
XAD-2 extract Neg L
*Neg: Negative; ND: Not detectable; L. Low toxicity; M: Medium toxicity.
Total flue gas OS cited.
Test not conducted.
"Refer to Table 2.
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L. R. Water/and, K. J. Urn, E. B. Higginbotham, R. M. Evans, andH. B. Mason are
with Acurex Corp., Mountain View, CA 94042.
Joshua S. Bowen is the EPA Project Officer (see below).
The complete report, entitled "Environmental Assessment of Stationary Source
/VOx Control Technologies: Final Report," (Order No. PB 82-249 350; Cost:
$25.50, 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:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
if\i. S. GOVERNMENT PRINTING OFFICE: 1982/559 -092/0518
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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Fees Paid
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Agency
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Penalty for Private Use $300
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