D A U.S. Environmental Protection Agency Industrial Environmental Research EPA-600/7-77-119a
> ฆ ปป Office of Research and Development Laboratory _
Research Triangle Park, North Carolina 27711 OClODGf 1 977
PRELIMINARY ENVIRONMENTAL
ASSESSMENT OF COMBUSTION
MODIFICATION TECHNIQUES:
Volume I. Summary
Interagency
Energy-Environment
Research and Development
Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into seven series.
These seven broad categories were established to facilitate further
development and application of environmental technology. Elimination
of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in related fields. The seven series
are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
A. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from
the effort funded under the 17-agency Federal Energy/Environment
Research and Development Program. These studies relate to EPA's
mission to protect the public health and welfare from adverse effects
of pollutants associated with energy systems. The goal of the Program
is to assure the rapid development of domestic energy supplies in an
environmentallycompatible manner by providing the necessary
environmental data and control technology. Investigations include
analyses of the transport of energy-related pollutants and their health
and ecological effects; assessments of, and development of, control
technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
REVIEW NOTICE
This report has been reviewed by the participating Federal
Agencies , and approved for publication. Approval does not
signify that the contents necessarily reflect the views and
policies of the Government, nor does mention of trade names
or commercial products constitute endorsement or recommen-
dation for use.
This document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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EPA-600/7-77-119a
October 1977
PRELIMINARY ENVIRONMENTAL
ASSESSMENT OF COMBUSTION
MODIFICATION TECHNIQUES:
Volume I. Summary
by
H.B. Mason, A.B. Shimizu, J.E. Ferrell,
G.G. Poe, L.R. Waterland, and R.M. Evans
Acurex Corporation
Aerotherm Division
485 Clyde Avenue
Mountain View, California 94042
Contract No. 68-02-2160
Program Element No. EHE624A
EPA Project Officer: Joshua S. Bowen
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, N.C. 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
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FOREWORD
The report summarizes results generated during the first 6 months of EPA Contract 68-02-2160:
"Environmental Assessment of Stationary Source N0x Combustion Modification Technologies." The EPA
Project Officer is J. S. Bowen and the Deputy Project Officer is R. E. Hall of the Combustion Re-
search Branch, IERL/RTP. This report was prepared by Aerotherm Division of Acurex Corporation.
Principal Contributors were: A. Balakrishnan, C. Castaldini, 2. Chiba, R. M. Evans, J. E. Ferrell,
H. B. Mason, G. R. Offen, G. G. Poe, K. Salvesen, A. B. Shimizu, L. Waterland and K. J. Wolfe.
Additionally, subcontract support was provided by H. M. Utidjian and P. Atkins of Equitable Envi-
ronmental Health Inc., and G. Lauer, A. Lloyd and R. MacGregor of Environmental Research and
Technology Inc. The Program Manager was W. H. Nurick; H. B. Mason was the Project Engineer.
C. B. Moyer provided technical review.
The contributions of the following individuals and organizations are gratefully acknowledged:
J. S. Bowen, R. E. Hall, 0. G. Lachapelle, W. S. Lanier, G. B. Martin and J. Viasser of the Combustion
Research Branch, IERL; R. Vosper of the Coen Company; S. Greenfield, L. Attaway and L. Husting of
Greenfield, Attaway and Tyler Company; D. W. Pershing and J. 0. L. Wendt of the University of Ari-
zona; D. P. Teixeira and R. M. Perhac of the Electric Power Research Institute; and A. Eschenroeder
and G. Hidy of Environmental Research and Technology.
iii
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TABLE OF CONTENTS
Section Page
1 INTRODUCTION 1-1
1.1 Background 1-1
1.2 NOx E/A Scope and Approach 1-3
1.3 Purpose of This Report 1-6
2 NOx SOURCE CHARACTERIZATION 2-1
3 POLLUTANT CHARACTERIZATION 3-1
4 N0X CONTROL CHARACTERIZATION 4-1
5 MULTIMEDIA EMISSION INVENTORY OF NOx SOURCES 5-1
6 EVALUATION OF INCREMENTAL EMISSIONS DUE TO NOx CONTROLS 6-1
7 ENVIRONMENTAL ASSESSMENT PRIORITIES 7-1
7.1 Evaluation of N0X Control Requirements 7-3
7.2 Summary of Source/Control Priorities 7-10
7.3 Pollutant/Impact Screening 7-17
7.4 Future Effort 7-24
v
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LIST OF TABLES
Table Page
2-1 Significant Stationary Fuel Combustion Equipment Types/Major Fuels 2-3
2-2 Summary of Source Characterization 2-6
4-1 Current or Planned Federal Standards of Performance for New Stationary
Sources 4-2
4-2 Summary of N0X Control Technology 4-3
4-3 Overall Evaluation of N0X Control Techniques 4-7
5-1 Summary of 1974 Stationary Source N0X Emissions by Fuel 5-5
5-2 1974 Summary of Air and Solid Pollutant Emission from Stationary Fuel
Burning Equipment 5-6
5-3 N0X Mass Emission Ranking of Stationary Combustion Equipment and Criteria Pol-
lutant and Fuel Use Cross Ranking 5-7
6-1 Evaluation of Incremental Emissions Due to N0X Controls Applied to Boilers . . 6-2
6-2 Evaluation of Incremental Emissions Due to N0X Controls Applied to IC
Engines 6-3
6-3 Evaluation of Incremental Emissions Due to N0X Controls Applied to Gas Turbines 6-4
7-1 Summary of Control Levels to Meet NO? Standard in Los Angeles, AQCR 024 .... 7-5
7-2 Control Prioritization for Los Angeles 7-6
7-3 Summary of Control Levels Required to Meet NO2 Standard in Chicago,
AQCR 067 7-8
7-4 Control Prioritization for Chicago 7-9
7-5 Evaluation of N0X E/A Source Priorities 7-12
7-6 Summary of N0X E/A Source/Control Priorities 7-16
7-7 Comparison of Pollutant Emission Levels with N0X Controls to Maximum Allowable
Emissions 7-19
7-8 Comparison of Baseline Pollutant Emission Levels to Maximum Allowable Emissions 7-20
7-9 Summary of Potential Pollutant/Combustion Source Hazards 7-23
vi
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SECTION 1
INTRODUCTION
This is the first in a series of 11 special reports to be documented in the "Environmental
Assessment of Stationary Source N0x Combustion Modification Technologies" (N0X E/A). The N0x E/A
is a 36-month program which began in July 1976. The program has two main objectives: (1) to iden-
tify the multimedia environmental impact of stationary combustion sources and N0X combustion modi-
fication controls; and (2) to identify the most cost-effective, environmentally-sound N0X combustion
modification controls for attainment and maintenance of current and projected N02 air quality stan-
dards to the year 2000. The first objective addresses the need to evaluate the environmental
soundness of current control technology, as well as to identify potential environmental stresses of
advanced techniques being developed for application in the 1980's and 1990's. The second objective
draws on the above results in combination with process studies and air quality models to rank
source/control combinations based on current or projected control implementation needs. These re-
sults are used both to prioritize the effort within the NO^ E/A and to guide the control develop-
ment program. This report documents the initial program results of compiling and evaluating data
on sources, controls, pollutants, and impacts to be considered, and of defining program priorities
on source/control combinations and effluent stream/impacts.
1.1 BACKGROUND
As a result of the 1970 Clean Air Act Amendments a moderate level of N0X control has been
developed and implemented for a variety of stationary combustion N0X sources. In 1971, the EPA
promulgated a primary and secondary National Ambient Air Quality Standard (NAAQS) for NOg of 100
ug/m3 (annual average). At that time, the EPA N0X abatement strategy for attaining and maintaining
the NAAQS for N02 relied heavily on N0X controls for mobile sources. As mandated by the Clean Air
Act, light-duty vehicle (LDV) emissions were to be reduced by 90 percent to a level of 0.25 g N02/km
(0.4 g/mile) by 1976. Stationary sources were to be regulated through EPA Standards of Performance
for New Stationary Sources (NSPS), which would be set as technology became available on the basis
of the best system of emissions reduction. To date, NSPS have been set for gas-, oil- and bitumin-
ous coal-fired large steam generators and nitric acid plants. NSPS have been proposed for
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lignite-fired large steam generators and gas turbines, and are in preparation for stationary IC
engines and intermediate-sized steam generators. A more stringent standard for bituminous coal-
fired large steam generators is also being prepared. Additional standards for new or existing
sources can be set through State Implementation Plans (SIPs) as required to attain and maintain air
quality in Air Quality Control Regions. As part of these SIPs, stationary source N0x controls have
been applied to new and existing utility boilers, large industrial boilers and gas turbines.
The stationary source regulatory program described above is leading to widespread applica-
tion of current control technology. A major part of the N0x E/A program will be directed at evalua-
ting these applications to identify the incremental environmental impact resulting from the use of
N0V controls. Additionally, process engineering studies will be conducted for the use of N0V con-
X X
trols on the major equipment categories. These studies will quantify the cost, efficiency impact
and operational impact of the use of current N0X control technology. The result will be a ranking
of source/control combinations based on overall environmental, economic and operational impact.
This information is intended to support control developers and users in selecting the most appro-
priate control techniques to meet regulatory standards. The results of the N0x E/A will also con-
tribute to the broad program of assessments of energy systems and industrial processes which is
being administered by EPA's Office of Research and Development. This assessment program involves
a series of coordinated efforts to evaluate the environmental impact and control potential of
multimedia effluents air, land and water from current and emerging energy and industrial pro-
cesses. The results of these efforts will define pollution control development needs and priorities,
identify economic and environmental trade-offs among competitive processes, and will ultimately guide
regulatory policy.
In addition to the assessment of current control technology noted above, the N0x E/A will
also evaluate emerging technology with potential for application in the 19801s and 1990's. It has
recently been determined that there is a potential need for advanced stationary source N0X control
technology in the 1980's and 1990's to maintain N02 air quality. This technology is in addition
to that described above as part of the original N0X abatement strategy formulated following the
1970 Clean Air Act Amendments. The recent change in the N0y abatement strategy has resulted from
Relaxation of the stringent mobile source emission standard with the emphasis in N0X
control switching to stationary sources
1-2
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Projections of high stationary source NO^ emissions in the 1980's and 19901o due to
- Projected rapid growth of stationary sources
Increasing stationary source use of coal and other fuels with high N0x potential
Emergence of advanced energy systems with potential environmental problems
Consideration of additional NOg air quality standards which may necessitate additional
implementation of control technology
Although the revised N0x abatement strategy is still under development, it appears that ad-
vanced control technology beyond that currently available will be needed to maintain the current
NAAQS or to attain and maintain additional l^-related air quality standards. Part of the N0x E/A
program will evaluate this emerging technology to identify potential environmental stresses which
should be considered in the control development program. As part of this effort, a systems analysis,
involving air quality modeling, will be conducted to indicate the best combination of current and
emerging control techniques to maintain air quality in the 1980's and 1990's in specific Air Quality
Control Regions. These results will assist in setting source/control priorities within the N0x E/A
program. They will also support control R&D groups concerned with providing a sufficient breadth
of environmentally-sound control techniques to meet the diverse control implementation requirements
in NOg-critical air quality control regions. In addition, the analyses will be useful to environ-
mental planners involved in formulating abatement strategies to meet current or projected air quality
standards.
1.2 N0x E/A SCOPE AND APPROACH
The scope of the N0X E/A, compatible with the program requirements discussed above, encom-
passes the following combinations of process parameters and environmental impacts:
Fuel combustion stationary N0X sources: utility, industrial, commercial, and residential
boilers; commercial and residential warm air furnaces; IC engines; gas turbines; indus-
trial process combustion; advanced energy systems; and minor sources. Other sources
(mobile and noncombustion) will be considered only to the extent that they are needed
to determine the N0X contribution from stationary combustion sources.
Conventional and alternate gaseous, liquid, and solid fuels
Combustion modification N0X controls with potential for implementation to the year 2000;
other controls (tail gas cleaning, mobile controls) will be considered only to estimate
the future need for combustion modifications
1-3
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Source effluent streams potentially affected by N0X controls
Nonstandard operating conditions during which the emissions may be affected by N0X
controls
Primary and secondary gaseous, liquid and solid pollutants potentially affected by N0X
controls
Pollutant impacts on human health and terrestrial or aquatic ecology
The possible combinations of the above parameters are far too large to treat comprehensively
in the program, so considerable emphasis particularly at the program outset is placed on screen-
ing these combinations of process parameters and potential impacts to arrive at program priorities.
This screening and prioritization will allow focusing the major effort on the sources, controls,
and potential impacts which are likely to be significant in the national N0x abatement strategy.
It also entails that effort in the early stages of the program will concentrate on near-term source/
control needs, while emphasis will be switched later to longer range control needs to the year 2000.
The comprehensive ranking of the process and impact combinations - which is the principal output of
the program will not be possible until most of the tasks in the program are complete. Throughout
the effort, however, priorities will be screened on the basis of the most recent findings, which
will be periodically updated and reevaluated as new data become available.
The program structure incorporating the objectives and approach described above is shown in
Figure 1-1. The top half of the figure shows the effort to set preliminary source/control priori-
ties which is covered in this report. The rectangular boxes denote specific subtasks while the
oval symbols show program output. The arrows show the sequence of subtasks and the major interac-
tions among tasks. The bottom half of the figure shows the major program effort which will be
initiated subsequent to this report.
The two major program tasks are: Environmental Assessment and Process Engineering (Task
B5); and Systems Analysis (Task C). Each of these tasks is designed to achieve one of the overall
objectives of the NOx E/A program cited earlier. In Task B5, the environmental, economic, and
operational impacts of specific source/control combinations will be assessed. On the basis of
this assessment, the incremental multimedia impacts from the use of combustion modification N0X
controls will be identified and ranked. Task C will in turn use the results of Task B5 to identify
and rank the most effective source/control combinations to comply, on a local basis, with the cur-
rent NOg air quality standards and projected NOg-related standards. As shown in Figure 1-1, the
1-4
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Emission Impacts & Emission Environmental Systems
Characterization (Bl) Standards (B2) Data (B3) Assessment (B5) Analysis (C)
Compile Baseline
and Controlled
Ewission Data
Identify and
Categorize *0,
Controls
Identify and Categorize
Multimedia Pollutants
NO* Sources
Evaluate Control
Effectiveness
and Cost
Survey Control Trends
and Emerging
Technology
Evaluate Pollutant
Transport and
Transformation
Identify Effluent
Strews t Operating
Develop Preliminary
Screeninq Model
Screen Control i
cm 3&sis of
Ef fectiveness
^ฆpile Fuel Consumption
I Composition Data
Compile Multimedia
Emission Factors
Survey Effluent and
Air Quality Standards
He Growth J Control
Scenarios, AQCR
Inventories
PRELIMINARY
E/A OF COMBUSTION
MODIFICATION
TECHNOLOGT
Quantify Multi-
nedia Pollutant
Impact Criteria
Differential Emissions
with N0X Controls ?
Screen Control Require-
ntents for Air duality
Generate Multimedia
Emission Inventory
Prelininary
Source/Control Priorities
on Basis of Potential
Imoact and Projected Use
Generate Source, fuel
I Emission Projections
Estimate
Haxiiwn Permissible
Concentrations
Define Sampling S
Analysis Requirements
r*enerate Process
Studies of Major
Source Categories
Select and Adaot
r Oualitv Model
Develop Regional &
AQCR Inventories
Project Potential
NOj Related Standards
Heritor
Ongoing Tests
Conduct
Test Programs
Identify Operational J
Cost Impact of Controls
Assess Pollution
Potential of Sources &
Effluent Strews
Impact Data
Evaluation &
Impact Criteria
4 NQ2 Standard
Scenarios*
Baseline
and Controlled
Emission Data
Assess Incremental
Environmental Impact
Due to 'J0X Controls
;sess Tontrol Sequ^re-
n*nts for alternate
ANNUAL AND
FINAL RฃPORTS
Baseline Effluent
Stream Control
SequiroMnts*
Research Deeds
for Definition or
Resolution of Problem*
Ranking of Potential
Environmental Problems
with N0 Controls*
lank Controls on 3asis
. of Multimedia Inpact
and Cost Effectiveness
'Denotes section of this
~To be
in Special reports
'lost Effective
Dptions for Maintenance
of Alternate
N0X Standards
Combustion Modification
Control Development
Figure 1-1. N0X E/A approach.
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key tasks supporting Tasks B5 and C are Baseline Emissions Characterization (Task Bl), Evaluation
of Emission Impacts and Standards (Task B2), and Emission Data (Task B3). An additional support
task of this program - Identification and Characterization of Alternate Clean Fuels for Area
Sources (Task B4) - has been omitted for clarity.
The initial work on this N0X program began with the compilation of process data and multi-
media emissions data for stationary N0X sources. Both uncontrolled baseline emission data as well
as data for sources using N0x controls were compiled. Process and emission data based on test re-
sults from related programs will continue to be incorporated as they become available throughout
the duration of the program.
These data were used to initiate the following preliminary characterizations and data eval-
uations: stationary source equipment and effluent streams, as well as baseline multimedia emissions
(Task Bl); multimedia primary and secondary pollutants and impacts (Task B2); and stationary source NO^
controls and incremental emissions due to control (Task B5). These characterizations and data
evaluations, together with the preliminary screening of future source/control requirements (Task C),
are documented in this report. This information will serve as a data base for the subsequent com-
prehensive process studies, as well as for refining emission inventories and impact criteria. It
will also help define requirements for subsequent field test programs and assist in setting priori-
ties for process and environmental assessment studies.
1.3 PURPOSE OF THIS REPORT
As noted above, the N0x E/A activities documented in this report began with compiling and
evaluating data and defining the program approach and priorities. This initial activity was thus
a first-pass review of existing data and techniques for all areas of the program. This preliminary
report will initiate these efforts and establish the approach and level of effort to be used in
various subtasks. The objectives of this report are to: (1) document the scope of the N0x E/A in
terms of sources, pollutants, impacts, and controls to be considered; (2) evaluate data on impact
criteria, control effectiveness, baseline multimedia emissions, and incremental impacts of N0X
controls; and (3) define preliminary priorities on source/control combinations and effluent stream/
impacts to be considered. Volume II, Technical Results, contains the detailed results on each of
these objectives. This summary volume focuses on the major conclusions on Objectives (2) and (3).
Specific subobjectives of the Volume II report which are summarized in the subsequent sec-
tions are as follows:
1-6
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t Establish categories of stationary fuel combustion N0V sources to be assessed in the NO
X *
E/A (Section 2)
Identify source effluent streams and operating modes for which the emissions may be per-
turbed by the use of N0X controls (Section 2)
Establish a preliminary set of pollutants and their impacts to be considered in the
source/control environmental assessments (Section 3)
ซ Compile and evaluate dose/response data on multimedia pollutant impact; tabulate impact
criteria for use in preliminary screening of the impact of source/effluent stream/control
combinations (Section 3)
Identify possible approaches and problems in conducting a generalized (nonsite specific)
impact assessment (Section 3)
Survey available N0X control techniques and specify the combustion modification technology
to be addressed in the program (Section 4)
Evaluate the status, effectiveness, cost, and operational impact of current and emerging
combustion modification techniques (Section 4)
Compile and evaluate N0X emissions data for all N0X sources; generate controlled nation-
wide N0X inventory (Section 5)
Compile and evaluate emission data on pollutants other than N0X for stationary fuel com-
bustion N0X sources; generate nationwide emissions inventory (Section 5)
Evaluate the effect of N0x controls on emissions of pollutants other than N0X (Section 6)
Define preliminary source/control priorities based on projected control implementations
requirements (Section 7)
Define preliminary effluent stream/pollutant priorities based on potential impact re-
sulting from the use of N0X controls (Section 7)
1-7
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SECTION 2
NOx SOURCE CHARACTERIZATION
In the preliminary N0X E/A effort, NOx sources were surveyed to identify appropriate source
categories and operating characteristics for consideration in the environmental assessments and
process studies. This source characterization encompassed the following steps:
Identify significant sources of N0X; group according to formative mechanism and nature
of release into the atmosphere
Categorize stationary combustion sources according to equipment and/or fuel characteris-
tics affecting the generation and/or control of combustion-generated pollution
Qualify equipment fuel categories on the basis of current and projected use and design
trends; develop a provisional list of equipment/fuel combinations to be carried through
the subsequent emission inventories, process studies, and environmental assessments
Identify effluent streams from stationary combustion source equipment/fuel categories
which may be perturbed by the use of N0X combustion modification controls
Identify operating modes (transients, upsets, maintenance) for which the emissions may
be perturbed by N0X combustion modification controls
The significant sources of oxides of nitrogen emitted to the atmosphere are shown on Figure
2-1. On a global basis, natural emissions due to biological decay and lightning comprise about
90 percent of emissions. In urban areas, however, up to 90 percent of the ambient N0X is due to
manmade sources, primarily combustion effluent streams. The emphasis in the N0X E/A will be on the
fuel combustion sources bracketed at the top of the figure. The remaining sources will be considered
only as required to gauge the emissions and impacts due to stationary fuel combustion.
The major stationary fuel combustion sources are further categorized on Table 2-1. This
table lists the major equipment design variations and fuels which are known to affect emissions
based on a survey of process characteristics and emission data. This list, together with a refined
breakdown of fuel type, will be used 1n emission inventories and ranking of potential environmental
2-1
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Combustion
-effluent stream
emissions
^Stationary
Fuel
"combustion '
Incineration
-Utility boilers
- Packaged boilers
-Warm air furnaces
-Gas turbines
-Reciprocating IC engines
-Industrial process combustion
-Advanced combustion processes
Emphasis
> of
N0x E/A
Mobile
Noncombustlon
effluent
stream
emissions
-Nitric add
Ad1p1c acid
Explosives
.Fertilizer
- Nitration
Fugitive
-emissions
-Natural
ฃ
Anthropogenic
Nitrogen cycle
Lightning
Open burning
Forest fires
Structural fires
. Minor processes
Figure 2-1. Sources of nitrogen oxide emissions.
2-2
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TABLE 2-1. SIGNIFICANT STATIONARY FUEL COMBUSTION
EQUIPMENT TYPES/MAJOR FUELS
Utility Sector (Field Erected Watertubes) Fuel
Tangential PC, 0, G
Wall fired PC, 0, G
Horizontal opposed and Turbofurnace PC. 0, G
Cyclone PC, 0
Vertical and stoker C
Packaged Boiler Sector
Watertube 29 to 73 MWa Pc> G> PG
(100M to 250 MBtu/hr)
Watertube <29 MWa C, 0, G, PG
(<100 MBtu/hr)
Firetube scotch 0, G, PG
Firetube HRT C, 0, G, PG
Firetube firebox C, 0, G, PG
Cast iron 0> G
Residential C, 0, G
Warm Air Furnace Sector
Central heaters 0> G
Space heaters G
Other residential combustion 0> G
Gas Turbines
Large >15 MWa (>20,000 hp) ฐป G
Medium 4 to 15 MWa
(5,000 to 20,000 hp) ฐป G
Small <4 MWa (<5,000 hp) ฐป G
Reciprocating IC Engines
Large bore >75 kW/cyla G
(>100 hp/cyl)
Medium 75 kW to 75 kW/cyla 0, G
(100 hp to 100 hp/cyl)
Small <75 kWa (<100 hp) G
2-3
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TABLE 2-1. Concluded
Industrial Process Heating
Glass melters
Glass annealing lehrs
Cement kilns
Petroleum
Catalytic crackers
Process heaters
Brick and ceramic kilns
Iron and steel coke oven
Underfi re
Iron and steel sintering machines
Iron and steel soaking pits and reheat ovens
PC
- Pulverized coal
C
Stoker coal or other coal
0
- Oil
G
- Gas
PG
- Process gas
aHeat input
2-4
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impacts from combustion sources. These equipment/fuel categories will also be used as subdivisions
of the process studies and for consideration in the field test program. Additionally, other factors
affecting emissions such as burner design and volumetric heat release rate will also be considered
in the process studies.
The equipment/fuel categories on Table 2-1 were surveyed with respect to design trends and
operating characteristics which would affect their treatment within the N0y E/A. Table 2-2 sum-
marizes the major results. The primary design types listed are those which, on the basis of de-
sign trends, are projected to be in widespread use in the 1980's. They are thus candidates for
application of N0X controls and will be considered for detailed treatment in the N0X E/A as further
discussed in Section 7. The secondary design types listed are those which are either diminishing
in use, or projected primarily for long-term application or otherwise unlikely to see widespread
use of N0X controls in the near term. These design types will be carried through the emissions in-
ventories and assessment of pollution potential but will generally be accorded less emphasis in the
process studies and field test programs. The listings of effluent streams and significant operating
modes on Table 2-2 are for the most general operating conditions for a given sector and may not apply
to all design/fuel combinations. The effluent streams identified on Table 2-2 were generally
carried through the emission inventories for later use in ranking pollution potential from specific
effluent streams. The data on the frequency and specific process conditions of nonstandard opera-
ting modes were very sparse, however. In general, nonstandard operating modes were not considered
further in the preliminary assessment due to the lack of data.
2-5
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TABLE 2-2. SUMMARY OF SOURCE CHARACTERIZATION
Sector
Primary Design
Types in N0X E/A
Secondary Design
Types in N0X E/A
Effluent Streams
Significant
Operating
Modes
Trends
Utility
boilers
Tangential,
wall fired,
horizontally opposed,
turbo
Cyclone, verti-
cal , stoker
Stack gas, ESP catch,
bottom and super-
heater hopper ash,
scrubber streams, ash
sluicing streams
Sootblowing,
on-off transients,
load transients,
upsets, combustion
addi ti ves
Coal firing in new units;
conversion to oil and
coal in existing units;
no new wet bottom, cy-
clones, stoker or verti-
cal units
Packaged
boilers
Watertubes,
scotch firetube
HRT firetube,
firebox fire-
tube, cast iron
and residential
Stack gas, particu-
late catch, hopper
ash
As above
Pulverized coal and
stokers in large water-
tubes; heavy oil and
stokers in smaller water-
tubes; heavy oil in fire-
tubes decreasing use of
HRT and firebox firetubes
Warm air
furnaces
Conmercial and
residential central
warm air furnaces
Space heaters,
other residen-
tial combustion
Flue gas
On-off cycling
transient
Oil firing in new units;
trend to high efficiency
in new units
Gas turbines
Utility and indus-
trial simple and re-
generative cycles
Combined cycles,
repowering
Flue gas
On-off transient,
load following,
idling at spin-
ning reserve
Trend to higher turbine
inlet temperature, larger
capacity and oil firing
in new units; rapid
growth projected
Reciprocating
IC engines
Turbocharged,
naturally aspirated
Blower
scavenged
Flue gas
On-off transients
idling
Low growth rate of diesel
units
Industrial
process
combusti on
Process heaters,
furnaces, kilns
Flue gas, particu-
late catch, hopper
ash
Charging opera-
tions, upsets,
starting transi-
ents
Increasing use of coal in
kilns; some use of syn-
thetic gases from coal
-------
SECTION 3
POLLUTANT CHARACTERIZATION
The multimedia pollutant characterization involved the following tasks:
Compile a list of potential pollutant species in gaseous, liquid and solid effluent
streams under standard and nonstandard operating conditions; identify potential secondary
pollutants from these primary pollutants
Survey research methodology for pollutant effects on human health and terrestrial and
aquatic ecology; evaluate the relevance of these methods to the N0X E/A impact assess-
ments
Generate estimates of ambient pollutant concentration limits for use in screening poten-
tial impacts
These results will be used in Section 7 to assist in prioritizing effluent stream/pollutant combina-
tions according to impact potential. Subsequently, this preliminary characterization will be ex-
panded for use in the environmental assessments of N0X controls.
The compilation of potential combustion-generated pollutants was categorized as follows:
Inorganic and organic nitrogen compounds
Inorganic and organic sulfur compounds
Hydrocarbons
- Alkanes
- Alkenes
- A1kynes
- Oxygenated HC
- Aromatic HC
Trace elements
3-1
-------
Emissions data were available for only a very few of the several hundred possible species included
in the above categories. Where data were unavailable, it was generally not possible to determine
which species in a class of compounds was most likely to be formed in combustion. In these cases
the total class of compounds was.provisionally included in the list of potential pollutants. Gen-
erally, inclusion of nonstandard operating conditions, e.g., process upsets, added a large number
of potential pollutants to the list of candidates. These added pollutants were mainly those that
are suspected of being emitted only under overall reducing conditions. A large number of possible
secondary pollutants were identified which could be formed from the potential primary pollutants. In
general, the potential for formation of secondary pollutants is highly dependent on the local com-
position of the atmosphere and is thus site specific.
The emphasis in the compilation of pollutant impact criteria was placed on gaseous stream
pollutants which affect human health through inhalation. One reason for this emphasis is that the
vast majority of combustion-generated pollutants which may be impacted by combustion modification
N0X controls are present in gaseous effluent streams. Another reason is that it is easier to iden-
tify and quantify the impacts of inhaled gaseous pollutants on human health than those of other
kinds of pollutants or receptors. Additionally, the effect of inhaled pollutants is more readily
generalized without regard to site-specific impact factors such as regional flora or fauna and
regional food chain vectors. A survey of research methods and data for pollutant effects on human
health showed there is no satisfactory current technique to quantify a maximum ground level pollutant
concentration where health effects become significant. Of the available methods for estimating impact
criteria, the use of occupational threshold limit values (TLV's) and lethal doses (LD50's) from
animal toxicologic work appears to be the most useful for screening pollutants on the basis of po-
tential impact. A method of relating TLV's and LD50's to ambient screening concentrations has been
developed by the Research Triangle Institute for the EPA. This method was used for the list of
candidate pollutants discussed previously. These results were subsequently used to screen the pol-
lution potential of source/effluent stream combinations. It should be mentioned, however, that there
are a number of limitations and qualifications in using this approach in impact assessment. These
are discussed in the Volume II report.
The survey of research methods and data for pollutants effects on terrestrial and aquatic
ecology showed that the use of a generalized impact criteria is far more limited than was the case
for human health impacts. Most pollutant impacts on the biota are site specific in that they
depend on the nature of the local terrestrial and aquatic ecosystems. Few tests have evaluated
interactive impacts of associated pollutants in effluent streams or of secondary pollutants.
3-2
-------
Additionally, criteria as to what constitutes unacceptable impact to terrestrial or aquatic eco-
systems are less well defined than for human health. Because of these and other problems, the use
of generalized biota impact criteria is limited in utility. The current effort gives only a very
preliminary "worst case" estimate of maximum concentration limits. These limits will be further
refined in preparing the special N0X E/A report on pollutant impacts and standards.
3-3
-------
SECTION 4
NOx CONTROL CHARACTERIZATION
The NO control characterization effort 1n the NO E/A preliminary assessment was conducted
X X
to identify the source/control combinations most likely to see significant use in the near term.
These results were used in Section 7 to determine the source/control priorities for the process
studies on near-term control applications. The control characterization also projects the effec-
tiveness, cost and schedule of advanced emerging control techniques. This information was used in
Section 7 together with air quality models to arrive at source/control priorities for far-term ap-
plication. The control characterization encompassed the following steps:
Survey stationary source N0X regulatory programs to show current and impending source
control requirements
Evaluate effectiveness, efficiency, cost, and operational impacts or current control tech-
nology for each major equipment category
Identify developmental status and projected uses of emerging control technology
Specify relative emphasis to be given to specific controls in the subsequent process
studies
The survey of stationary source N0X control regulations for new and existing sources shows
that there is impending widespread application of moderate levels of combustion modification con-
trols. Table 4-1 lists current or planned emission standards via the federal Standards of Perfor-
mance for New Stationary Sources. Here, as with state or local standards for existing sources, the
trend is toward regulation of smaller sources and more stringent regulations for larger sources.
Utility boilers are by far the most extensively regulated source. The majority of remaining control
applications are for utility size gas turbines. A few areas have regulated Industrial boilers
and reciprocating IC engines, but these standards are not always rigidly enforced. N0x standards for
industrial process furnaces and residential heating systems are rare and nonexistent respectively.
The results of the characterization of current and emerging control technology for the major
equipment categories are summarized on Table 4-2. These results show that current technology is
4-1
-------
TABLE 4-1. CURRENT OR PLANNED FEDERAL STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES
Source
Status
Standard
Reference
Steam generators; heat input
>73 MW (250 MBtu/hr)
Gaseous fossil fuel-fired
Promulgated 12-23-71
86 ng/J (0.2 lb/106 Btu)
36
FR
24877
Liquid fossil fuel-fired
Promulgated 12-23-71
130 ng/J (0.3 lb/106 Btu)
36
FR
24877
Solid fossil fuel-fired
(except lignite)
Promulgated 12-23-71
300 ng/J (0.7 lb/106 Btu)
36
FR
24877
Mixed fossil fuel-fired
Promulgated 12-23-71
86X + 130Y + 300Za
X + V + z ng/J
36
FR
24877
Lignite coal-fired
Proposed 12-22-76
260 ng/J (0.6 lb/106 Btu)
41
FR
55792
Wood residue-fired
Amended 11-22-76
Add wood residue to per-
missible mixed fuel firing
standard
41
FR
51397
Coal-fired (except lignite)
SSEIS^ under review
260 ng/J (0.6 lb/106 Btu)
Gas turbines; heat input
>10.7 GJ/hr (10.2 MBtu/hr)
Proposed 10/3/77
75 ppm (15 percent O2)
42
FR
53782
Stationary IC engines
SSEIS under review
Intermediate size steam
generators
Under study
aX, Y, and Z are the percent of total heat input derived from gaseous, liquid and solid fossil fuels
^Standards Support and Environmental Impact Statement
-------
TABLE 4-2. SUMMARY OF NOx CONTROL TECHNOLOGY
Equi pment/
Fuel
Category
Current Technology
Emerging Technology
Comments
Available
Control
Technique
Achievable
N0X Emission
Level ng/J
(lb/106 Btu)
Estimated
Differential
Annual Cost
Operational
Impact
Near Term
1977-1982
Far Term
1983-2000
Existing coal-
fired utility
boilers
LEA + OSC
(OFA, BOOS,
BBF); new
burners
260-300
(0.6 - 0.7)
20-30*/kW
Possible
increase in
corrosion &
slagging &
carbon in
flyash
Advanced low
N0X burners
Ammoni a
injection;
flue gas
treatment
Ammonia injection,
FGT potential
supplement to CM if
needed
New coal-fired
utility
boilers
LEA + OFA;
new
burners
215-260
(0.5 - 0.6)
10-20
-------
TABLE 4-2. Continued
Equipment/
Fuel
Category
Current Technology
Emerging Technology
Correnents
Available
Control
Technique
Achievable
N0X Emission
Level ng/J
(lb/106 Btu)
Estimated
Different! al
Annual Cost
Operational
Impact
Near Term
1977-1982
Far Term
1983-2000
Stoker-fired
industrial
watertube
boilers
LEA + OFA
150-190
(0.35 - 0.45)
1.8-2.34/
(kg/hr)a
Possible
~V/c increase
in fuel con-
sumption;
corrosion;
slagging of
grate
(retrofit)
Inclusion of
OFA in new
unit design
Fluidized bed
combustion;
ammoni a
injection
Current technology
still being
developed
Gas-fired
industrial
watertube
boilers
LEA + OSC
(OFA, BOOS,
BBF)
86-130
(0.2 - 0.3)
1.4-1.8*/
(kg/hr)a
-1% increase
in fuel con-
sumption;
flame
instability;
boiler vi-
bration
(retrofit)
Low N0X bur-
ners; OFA in
new unit
design
Optimized
burner/firebox
design; ammonia
i njection
Current technology
still undergoing
development
Industrial
fi retube
boilers
LEA + FGR;
LEA + OSC
65-110
(0.15 - 0.25)
7-14*/
(kp/hr)
-1% increase
in fuel con-
sumption;
flame insta-
bility
(retrofit)
Low NOx burn-
ers; OFA or
FGR in new
unit design
Optimized
burner/firebox
design
Development continuing
on current technology
Gas turbines
Water,
steam
injection
110-150
(0.25 - 0.35)
$1-2/kW
-1% increase
in fuel con-
sumption;
affects only
thermal
Advanced com-
bustor de-
signs for
dry N0X con-
trols
Catalytic com-
bustion; ad-
vanced can
designs
Current technology
widely used
(Continued on page 4-5)
-------
TABLE 4-2. Concluded
Equipment/
Fuel
Category
Current Technology
Emerging Technology
Comments
Available
Control
Technique
Achievable
N0X Emission
Level ng/J
(lb/106 Btu)
Estimated
Differential
Annual Cost
Operational
Impact
Near Term
1977-1982
Far Term
1983-2000
Residential
furnaces
Low NOj,
burner/
f i rebox
design
(oil)
25-40
(0.06 - 0.1)
$0.14-0.29/
kW
($40-80/(MBtu/
hr))
~5% decrease
in fuel con-
sumption
Advanced
burner/fi re-
box design
(gas & oil)
Catalyti c
combustion
Current technology
still being tested
IC engines
Fine
tuning;
changing
A/F
1,070-1,290
(2.5 - 3.0)
$0.70-2.00/kW
($0.5-1.5/
BHP)
5-10% in-
crease in
fuel con-
sumption;
misfiring;
poor load
response
Include mod-
erate con-
trol in new
unit design
Advanced head
designs
Technology still being
tested
Industrial
process
furnaces
LEA
85-210
(0.2 - 0.5)
Unknown
Unknown
Low N0X
burners;
development
of external
controls
(FGR, OSC)
on retrofit
basis
Possible inclu-
sion in new
unit design
Control development
in preliminary stages
akg/hr steam produced
-------
dominated by combustion process modification. Emerging technology is also centered around combustion
modifications. Other approaches, such as flue gas treatment, may be used in the 19801s to augment
combustion modification if required by stringent emission standards.
The level of combustion modification control available for a given source depends on the im-
portance of that source in the regulatory program discussed above. Utility boilers have been the
most extensively regulated and accordingly, the technology is the most advanced. Available tech-
nology ranges from operational adjustments such as low excess air and biased burner firing to in-
clusion of overfire air ports or low-NOx burners in new units. Some adverse operational impacts
have been experienced with use of combustion modifications on existing equipment. In general, these
problems have been solved through combustion engineering or by limiting the degree of control appli-
cation. With factory-installed controls on new equipment, operational problems have been minimal.
The technology for other sources is less well developed. Effective control techniques for
utility boilers are being demonstrated on existing industrial boilers. Here, as for utility boilers,
the emphasis in emerging technology is on developing controls applicable to new unit design. Advanced
low-NOx burners and/or advanced off-stoichiometric combustion techniques are the most promising
concepts. This holds true for the other source categories as well. The R&D emphasis for gas tur-
bines, warm air furnaces, and reciprocating IC engines is on developing optimized combustion chamber
designs matched to the burner or fuel/air delivery system. Control development for the diverse
types of industrial process equipment is in a preliminary stage. To date, only minor operational
adjustments have been tried.
Table 4-3 summarizes the status and effectiveness of general control techniques. As noted
above, a number of techniques are applicable for operational adjustments and hardware modifications
to either new or existing units. The trend, however, is toward new burners or off-stoichiometric
combustion combined with low excess air. This approach yields a higher degree of control, is
more cost effective and minimizes adverse operational impacts.
The final column on Table 4-3 evaluates controls with respect to their treatment in the NQX
E/A. This evaluation is discussed further in Section 7 where priorities are set on near- and far-
term source/control applications. This evaluation is also used to scope the assessment of incre-
mental emissions due to N0X controls discussed in Section 6.
4-6
-------
TABLE 4-3. OVERALL EVALUATION OF NOx CONTROL TECHNIQUES
Control
Technique
Existing
Applications
Effectiveness
Operational
Impact
Projected
Applications
Control
Evaluation
for N0X E/A Effort
Low excess air
(LEA)
Retrofit and new
utility boilers;
some use in indus-
trial boilers
10SS to 30% for
thermal and fuel
Nฐx
Increase in effi-
ciency; amount lim-
ited by smoke or
CO at very low EA
Widespread use for
efficiency in-
crease; incorpor-
ate into advanced
designs all sources
Primary emphasis near-
term and far-term appli-
cations (all sources);
combined with OSC & bur-
ner mods for far-term appl.
Flue gas recircu-
lation (FGR)
Retrofit use on
many gas- and oil-
fired utility
boilers; demon-
strated on indus-
trial boilers
20% to 50% for
thermal N0~; no
effect on fuel
NQx
Possible flame in-
stability; in-
creased vibration
Possible use in new
industrial boiler
designs
Primary emphasis near-term
applications large boilers;
possible far-term industrial
boiler application
Off stoichiometric
combustion (OSC)
incl. OFA, BOOS,
BBF
New and retrofit
use on many util-
ity boilers; dem-
onstrated on in-
dustrial boilers
20% to 50% for
thermal and fuel
N0X
No major impact
with new design;
potential for flame
instability, effi-
ciency decrease,
increased corrosion
(coal-fired) with
retrofit
Widespread use in
large boilers; in-
corporate into ad-
vanced designs
Primary emphasis near-
term and far-term appli-
cations all sources
Load reduction
Some retrofit use
on gas and oil
utility boilers;
enlarged fireboxes
on new coal units
0% to 40% for
thermal N0x
Decrease in effi-
ciency and power
output; limited by
spare capacity and
smoke formation
Enlarged fireboxes
used in new unit
design; limited use
for retrofit
Secondary emphasis near-
term applications (boilers);
combined with OSC or burner
mods for far-term appl.
Burner
modifications
New and retrofit
use on utility
boilers; demon-
strated on resi-
dential furnaces
30% to 60% for
thermal and fuel
NOx
No major impact
with new design;
retrofit use con-
strained by firebox
characteristics
Incorporate into
advanced designs
utility, industrial
boilers, residen-
tial, process fur-
naces, GT; combine
with OSC
Primary emphasis near- and
far-term applications all
sources
(Continued on page 4-8)
-------
TABLE 4-3. Continued
Control
Technique
Existing
Applications
Effectiveness
Operational
Impact
Projected
Applications
Control
Evaluation
for N0X E/A Effort
Mater, steam
injection
Widely used for gas
turbines
30% to 70% for
thermal N0X
Slight decrease in
efficiency; limited
by CO formation;
power output
increases
Use in new gas tur-
bines; possible use
in process furnaces
Primary emphasis near-term
applications, gas turbines;
possible far-term indus-
trial process application
Reduced air
preheat (RAP)
Widespread use in
large turbocharged
IC engines
102 to 40% for
thermal N0x
Slight decrease in
efficiency, in-
crease power output
Continued use in
IC engines
Secondary emphasis
Anmonia injection
Demonstrated on
oil- and gas-fired
industrial boilers
40% to 70% for
thermal and fuel
NOx
Retrofit use lim-
ited; possible ad-
verse environmental
impact
Use in large
boilers in some
areas (19801s}
Primary emphasis far-
term application to large
boilers; evaluate impact
with coal firing
Fuel
denitrifi cation
Oil denitrifi cation
accompanies desul-
furization for some
large boilers
10% to 40% for
fuel NO
X
No adverse effects
Use of oil de-
nitrification in
large boilers as
supplement to CM
tech.
Secondary emphasis; eval-
uate as alternate fuel
Fuel additives
Fuel additives for
N0X not used
Generally in-
effective for dir-
ect N0X reduction
Byproduct emissions
formed
Additives for cor-
rosion, fouling,
particulate, smoke,
etc. can provide
increased flexi-
bility with CM tech.
on large boilers
Secondary emphasis; con-
sider impact of additives
Alternate and
mixed fuels
Combustion of low
nitrogen alternate
fuels being
demonstrated
Varies
Varies
Combined cycles and
residential and
commercial heating
systems
Secondary emphasis far-term
application; evaluate dif-
ferential impact of fuel
switching; transfer results
of other E/A's .
(Continued on page 4-9)
-------
TABLE 4-3. Concluded
Control
Technique
Existing
Applications
Effectiveness
Operational
Impact
Projected
Applications
Control
Evaluation
for N0x E/A Effort
Catalytic
combustion
Only tested in
experimental
combustors
>90% for thermal
NO
X
Requires clean
fuel; combustors
limited by cata-
lyst bed temp,
capability
Gas turbines and
residential and
commercial heating
systems
Primary emphasis far-term
applications; compare im-
pact to burner mods, al-
ternate fuels
Fluidized bed
combustion
Tested in pilot/
prototype
combustors
20% to 50% for
fuel N0X (pres-
surized FBC)
Requires sulfur
acceptor
Combined cycle,
utility boilers,
industrial boilers
(19801s)
Transfer results from
FBC E/A; compare impact
to combustion modifications,
conventional combustion
Flue gas
treatment (FGT)
Used in Japan on
large boilers
40% to >90% for
fuel and
thermal N0x
Requires temp, con-
trols, catalyst,
scrubbing soln.,
or oxidizing agent;
possible adverse
environmental impact
Possible supple-
ment to CM for
utility and large
industrial boilers
(1980's)
Secondary emphasis; trans-
fer results of other
studies to compare impact
to combustion mods
-------
SECTION 5
MULTIMEDIA EMISSION INVENTORY OF NOx SOURCES
A multimedia emission inventory was generated for the stationary fuel combustion source/fuel
combinations discussed in Section 2. The Inventory for NOx emissions was extended to include all
other sources of N0X (mobile, noncombustion, fugitive) in order to compare the contribution from
stationary combustion sources. Tbง NO^ inventory accounts for the degree of control applied to new
and existing utility boilers. Multimedia pollutants Inventoried include the primary criteria pol-
lutants (N0V, SO,., CO, HC, particulates), sulfates, polycyclic organic matter (POM), trace metals,
X A
and liquid or solid effluent streams. Insufficient data were available to quantify emissions for
other potential pollutants, The Inventory 1s confined tg ste^y-state standard operation since
emission data during nonstandard operation (on=0ff transients, upsets, soot blowing) were generally
not available.
This Inventory will serve as the base for assessing potential pollution problems 1n the
absence of N0X controls and for weighing the ineremental emission Impact due to the use of N0X con-
trols. The inventory will also be used as the reference for the subsequent projections to the year
2000 In fuel and equipment use and stationary source emissions. Data gaps identified in the emis-
sion factor compilation highlight areas where further testing is needed 1n the N0X E/A or other
programs.
The emission inventory was generated through the following sequence:
Compile fuel consumption data for the categories of combustion sources specified in
Section 2
- Subdivide fuel consumption based on fuel-bound pollutant precursor composition
Compile multimedia emission data
- Base fuel-dependent pollutant emission factors on trace composition of fuels
- Base combustion-dependent pollutant emission factors on unit fuel consumption for
specific equipment designs
Survey the degree to which N0X, S0X> particulates are controlled
5-1
-------
Generate emissions inventory
t Rank sources according to emission rates; compare to results of previous inventories
Volume II of this report gives a detailed breakdown of fuel consumption emission factors
and total emissions for each equipment/fuel combination. This summary is confined to sector emis-
sion totals.
The distribution of anthropogenic N0x emissions is shown on Figure 5-1 for 1974, the most
recent year for which complete fuel consumption data were available. Stationary source emissions
are further subdivided by sector in Figure 5-2 and by fuel type in Table 5-1. The utility boiler
emission estimates account for the reduction resulting from the use of N0x controls. Based on a
survey of boilers in areas with N0X emission regulations, it is estimated that application of
N0X controls in 1974 resulted in a 3.1 percent reduction in nationwide utility boiler emissions.
This corresponds to a 1.6 percent reduction in stationary fuel combustion emissions. Reduction
due to use of controls on other sources was negligible in 1974.
In general, the stationary source N0X emission total and the distribution among equipment
types for 1974 show little change relative to earlier inventories for the year 1972. Also, the
current inventory shows generally good agreement with recent inventories done by EPA's Office of
Air Quality Planning and Standards and other groups. One exception is for industrial packaged
boilers. Here, recent estimates by various groups differ by as much as a factor of 2, due primarily
to uncertainty in total fuel consumption for this sector.
The emission inventory results for other pollutants are shown on Table 5-2. The data quality
for the criteria pollutants is regarded as good and the results of the current inventories
agree reasonably with other recent inventories. The data for the noncriteria pollutants and
liquid or solid effluent streams, however, were sparse and exhibited large scatter. The emission
factors for POMs, for example, varied by as much as two orders of magnitude. Table 5-2 thus shows
a high and low estimate for total POM emissions. There are several ongoing field test programs
which are sampling noncriteria pollutants. The current inventory will be updated with these results
before the Impacts of these emissions are assessed.
Table 5-3 ranks equipment/fuel combinations by annual nationwide N0X emissions and lists the
corresponding ranking on fuel consumption and emissions of criteria pollutants. Although there were
over 70 equipment/fuel combinations inventoried, the 30 most significant account for over 90 percent
of N0X emissions. The ranking of a specific equipment/fuel type is dependent both on total installed
capacity and emission factors. A high ranking, therefore, does not necessarily imply that a given
5-2
-------
Incineration 0.2%
Noncombustion 0.9%
Fugitive 2.3%
Stationary fuel combustion
Mobile sources
45.2%
1974 Stationary Combustion Source N0V Emissions
1,000 Mq
1,000 tons
Percent
Total
Stationary Fuel Combustion
10,954
12,070
(51.4)
Fugitive Emissions
498
548
(2.3)
Noncombustion
193
212
(0.9)
Incineration
40
44
(0.2)
Mobile Sources
9,630
10,600
(45.2)
TOTAL
21,315
23,474
100
Figure 5-1. Distribution of anthropogenic N0X emissions for the year 1974
(stationary fuel combustion: controlled NO levels).
X
5-3
-------
Industrial Process Combustion 3.65%
Noncombustion 1.6%
Warm Air Furnaces 2.7% \
Gas Turbines 3.76% v \
Fugitive 4.4% v
Reciprocati ng
IC Engines
15.9%
Packaged Boilers
20.1
1974 Stationary Combustion Source N0X Emissions
1 ,000 Mq
1,000 Tons
Percent
Total
Utility Boilers
5,566
6,122
47.6
Packaged Boilers
2,345
2,383
20.1
Warm Air Furnaces
321
353
2.7
Gas Turbines
440
484
3.76
Reciprocating IC Engines
1,857
2,040
15.9
Industrial Process Combustion
425
470
3.65
Noncombustion
193
212
1.6
Incineration
40
44
0.3
Fugiti ve
498
548
4.4
TOTAL
11,685
12,861
100
Figure 5-2. Distribution of stationary anthropogenic N0X emissions for the year 1974
(stationary fuel combustion: controlled N0X levels).
5-4
/
-------
TABLE 5-1. SUMMARY OF 1974 STATIONARY SOURCE NOx EMISSIONS
BY FUEL
Sector
Coal
011
Gas
Total
Utility Boilers
3,564
(31.0)
848
(7.4)
1156
(10.1)
5566
(47.6)
Packaged Boilersฎ
679.7
(5.9)
886
(7.7)
779
(6.8)
2344.7
(20.1)
Warm Air Furnaces
129
(1.1)
190
(1.6)
320
(2.8)
Gas Turbines
309
(1.9)
133
(1-0)
442
(3.8)
Reciprocating IC
Engines
456b
(3.9)
1400
(12.2)
1856
(16.2)
Industrial Proress
Heating
425,8
(3.64)
Noncombustion
193
(1.7)
Incineration
40
(0.34)
Fugitive
>
498
(4.3)
Total
4,243.7
(37.0)
2,628
(22.1)
3,658
(31.7)
11,685
aIncludes steam and hot water commercial and residential heating units
^Includes gasoline
5-5
-------
TABLE 5-2. 1974 SUMMARY OF AIR AND SOLID POLLUTANT EMISSION FROM STATIONARY FUEL
BURNING EQUIPMENT
N0xb
o
X
HC
CO
Part
Sulfates
POM
Dry
Ash Removal
Sluiced
Ash Removal
Utility Boilers
5,566
16,768
29.5
270
5,965
231
0.01 - 1.2
6.18
24.78
Packaged Boilers
2,345
6,405
72.1
175
4,930
146
0.2 - 67.8
4.41
1.07
Harm Air Furnaces
& Misc. Comb.
321
232
29.7
132.6
39.3
6.4
0.06
Gas Turbines
440
10.5
13.7
73.4
17.3
a
a
Reclp. IC Engines
1,857
19.6
578
1,824
21.5
a
a
Process Heating
425.8
1005
166
10,039
6,216.7
a
a
--
TOTAL
10,954
24,440
889
12,511
17,190
382
69
aMo emission factor available
Controlled N0X
cBased on 80 percent hopper and flyash removal by sluicing methods; 20 percent dry solid removal
-------
TABLE 5-3. N0X MASS EMISSION RANKING OF STATIONARY COMBUSTION EQUIPMENT AND CRITERIA POLLUTANT AND FUEL USE CROSS RANKING
Sector
Equipment Type
Fuel
Annual N0X
Emissions
(Hg)
Cumulative
(Mg)
Cumulative
(Percent)
Fuel
Rank
S0X
Rank
CO
Rank
HC
Rank
Part
Rank
1
Utility Boilers
Tangential
Coal
1,410,000
1,410,000
13.1
1
1
7
16
2
2
Reciprocating IC
Engines
>75 kW/cyl
Gas
1,262,000
2,672,000
24.8
21
>30
4
1
>30
3
Utility Boilers
Hall Firing
Coal
946,000
3,618,000
33.5
3
2
6
23
5
4
Utility Boilers
Cyclone Furnace
Coal
863,500
4,481,500
41.5
6
3
12
9
13
5
Utility Boilers
Hall Firing
Gas
738,300
5,219,800
48.4
4
>30
13
28
>30
6
Utility Boilers
Kail Firing
Oil
481,000
5,700,800
52.8
8
9
17
27
18
7
Utility Boilers
Horizontally Opposed
Gas
378,700
6,079,500
56.3
14
>30
24
>30
>30
8
Reciprocating IC
Engines
75 kW to 75 kW/cyl
Oil
325,000
6,404,500
59.4
>30
>30
3
3
26
9
Packaged Boilers
Watertube >29 MM
Gas
318,500
6,723,000
62.3
16
>30
29
19
>30
10
Packaged Boilers
Watertube Stoker <29 MW
Coal
278,170
7,001,170
64.9
7
4
11
4
1
11
Utility Boilers
Horizontally Opposed
Coal
270,800
7,271,970
67.4
23
5
>30
>30
7
l
12
Packaged Boilers
Watertube >29 MW
Oil
232,480
7,504,450
69.5
26
16
>30
26
22
13
Utility Boilers
Tangential
011
208,000
7,712,450
71.5
12
10
27
>30
19
14
Packaged Boilers
Flretube Scotch
Oil
203,990
7,916,440
73.4
11
11
>30
>30
16
15
Packaged Boilers
Watertube <29 MW
Gas
180,000
8,096,440
75.0
5
>30
>30
22
>30
16
Utility Boilers
Horizontally Opposed
Oil
177,900
8,274,340
76.7
>30
17
>30
>30
27
17
Packaged Boilers
Watertube <29 MW
Coal
164,220
8,438,560
78.2
>30
8
>30
>30
9
16
Industrial
Process Comb.
Forced & Natural Draft
Refinery Heaters
Oil
147,350
8,585,910
79.6
>30
29
>30
18
21
19
Utility Boilers
Tangential
Gas
146,000
8,731,910
80.9
13
>30
>30
>30
>30
20
Packaged Boilers
Firetube Firebox
Oil
139,260
8.871,170
82.2
17
13
>30
>30
20
-------
TABLE 5-3. Concluded
Sector
Equipment Type
Fuel
Annual N0X
Emissions
(Mg)
Cumulative
(Mg)
Cumulative
(Percent)
Fuel
Rank
S0X
Rank
CO
Rank
HC
Rank
Part
Rank
21
Packaged Boilers
Watertube Stoker
Coal
125,350
8,996,520
83.4
>30
7
28
29
8
22
Gas Turbines
4 to 15 MW
Oil
118,500
9,115,020
84.5
30
>30
15
14
>30
23
Packaged Boilers
Watertube <29 MM
Oil
116,430
9,231,450
85.6
27
15
>30
>30
23
24
Wans Air Furnaces
Central
Gas
106,300
9,337,750
86.5
2
>30
10
8
25
25
Packaged Boilers
Firetube Stoker <29 MW
Coal
102,040
9,439,790
87.5
29
6
>30
10
6
26
Packaged Boilers
Firetube Scotch
Gas
98,010
9,537,800
88.4
19
>30
>30
>30
>30
27
Gas Turbines
>15 MW
Oil
97,400
9,635,200
89.3
>30
>30
>30
30
>30
28
Reciprocating IC
Engines
>75 kW/cyl
Oil
94,000
9,729,200
90.2
>30
>30
22
13
>30
29
Industrial
Process Ccnb.
Forced & Natural Draft
Refinery Heaters
Gas
92,608
9,821,808
91.0
15
>30
>30
7
30
30
Utility Boilers
Vertical and Stoker
Coal
90,900
9,912,708
91.9
>30
12
>20
>30
>10
-------
source is a high emitter. In general, coal-fired sources rank high in S0X and particulate emissions
while IC engines dominate the emissions of CO and hydrocarbons. The N0X emission ranking is used in
Section 7, together with estimates of potential environmental impact and projected control applica-
tion, to set program priorities on source/fuel combinations.
5-9
-------
SECTION 6
EVALUATION OF INCREMENTAL EMISSIONS DUE TO NOx CONTROLS
This section summarizes a preliminary evaluation of the demonstrated and potential effects
of combustion modification N0X controls on Incremental emissions. The results will serve to scope
and guide priorities for subsequent N0X E/A efforts in incremental emission data compilation, im-
pact characterization, and control process studies. Attention is focused on flue gas emissions from
steady-state operation of the major sources using near-term N0X controls, since these situations are
the most important in the program and are the only ones for which any significant data exist. Sub-
sequent effort will consider liquid and solid effluents, minor sources, and alternate or advanced N0x
controls. Also, the discussion here is concerned only with estimating incremental emission rates
without regard to potential impact. Ultimately, the significance of the incremental emissions de-
pends on the baseline uncontrolled pollutant emission rates (summarized in Section 5) and the maxi-
mum acceptable ambient pollutant concentration (discussed in Section 3) as well as other factors such
as pollutant transport and transformation. Preliminary screening of potential incremental impacts
due to N0X controls, considering these factors, is summarized in Section 7.
Evaluation results on the potential for incremental emissions with N0X controls are
summarized in Tables 6-1 through 6-3 for boilers, IC engines and gas turbines respectively. The con-
trol techniques and pollutants are qualitatively classified into one of the following three groups
according to potential for increased emissions:
High potential emissions impact, where the emissions data unambiguously show that apply-
ing the N0X control results in significantly increased emissions of a specific pollutant
Intermediate potential emissions impact, where preliminary screening of formative
mechanisms indicates that the N0X control could conceivably cause increased pollutant
emissions, but confirming data are lacking, contradictory, or inconclusive
Low potential emissions impact, where the emissions data clearly show that specific
pollutant emission levels decrease when the N0X control 1s applied, or where the pre-
liminary screening definitely indicates a similar conclusion, even though data are
lacking
6-1
-------
TABLE 6-1. EVALUATION OF INCREMENTAL EMISSIONS DUE TO NOx CONTROLS APPLIED
TO BOILERS
Incremental
Emission
N0X Control
CO
Vapor Phase
HC
Sulfate
Particulate
Organics
Segregating
Trace Metals
Nonsegregating
Trace Metals
Low Excess Air
++
0
+
0
++
+
0
Staged
Combustion
0
0
+
+
++
+
0
Flue Gas
Recirculation
0
0
+
+
+
+
+
Reduced Air
Preheat
0
0
+
0
+
0
+
Reduced Load
0
0
+
0
+
0
0
Water
Injection
0
0
+
+
+
0
0
Arrmonia
Injection
0
0
++
+
0
+
0
Key: ++ denotes having high potential emissions impact
+ denotes having intermediate potential emissions impact, data needed
0 denotes having low potential emissions impact
-------
TABLE 6-2. EVALUATION OF INCREMENTAL EMISSIONS DUE TO NOx CONTROLS APPLIED
TO IC ENGINES
Incremental Emission
N0X Control
CO
Vapor Phase
HC
Sulfate
Particulate
Organics
Segregating
Trace Metals
Nonsegregating
Trace Metals
Retard
Ignition
++
+
0
++
+
0
0
Increase A/F
Ratio
0
++
++
0
0
0
0
Decrease A/F
Ratio
++
++
0
+
+
+
0
Exhaust Gas
Recirculation
+
+
0
++
+
+
0
Decrease
Manifold Air
Temperature
0
++
+
0
0
+
0
Stratified
Charge
Cylinder
Design
+
+
0
+
+
+
0
Derate
++
++
+
0
0
+
0
Increase Speed
+
+
0
+
+
+
0
Mater Injection
+
++
0
+
+
+
0
Key: ++ denotes having high potential emissions impact
+ denotes having intermediate potential emission impact, data needed
0 denotes having low potential emissions impact
-------
TABLE 6-3. EVALUATION OF INCREMENTAL EMISSIONS DUE TO NOx CONTROLS APPLIED
TO GAS TURBINES
Incremental Emission
NO Control
X
CO
Vapor Phase
HC
Sulfate
Particulate
Organics
Segregating
Trace Metals
Nonsegregating
Trace Metals
Water or Steam
Injection
++
+
0
+
+
+
0
Lean Primary
Zone
0
0
+
0
0
+
0
Early Quench
with Secondary
Air
0
0
0
+
+
+
t
i
o i
Increase Mass
Flowrate
+
+
0
+
+
+
I
o 1
Exhaust Gas
Recirculation
+
+
0
+
+
+
i
o i
Air Blast/Air
Assist
Atomization
0
+
0
+
+
i
i
0
Reduced Air
Preheat
0
0
+
0
0
+
0
Reduced Load
++
++
+
++
+
. _ . .
+
0
Key: ++ denotes having high potential emissions impact
+ denotes having intermediate potential emissions impact, data needed
0 denotes having low potential emissions impact
-------
As Table 6-1 illustrates, applying preferred N0X combustion controls to boilers should have
few adverse effects on incremental emissions of CO, vapor phase hydrocarbons or particulates. It
is true that indiscriminantly lowering excess air can have drastic effects on boiler CO emissions,
and that particulate emissions can increase with off-stoichiometric combustion and flue gas recir-
culation. However, with suitable engineering during development and implementation of these modifi-
cations, adverse incremental emissions problems can be minimized. In contrast, incremental emissions
of sulfate, organics, and trace metals have intermediate to high potential impact associated with
applying almost every combustion control. For trace metal and organic emissions, substantiating
data are largely lacking, but fundamental formation mechanisms give cause for justifiable concern.
In the case of sulfate emissions, fundamental formation mechanisms suggest that these emissions
should remain unchanged or decrease with all controls except ammonia injection. However, complex
interactive effects are difficult to elucidate, and this pollutant class is sufficiently hazardous
to justify expressing some concern in the present absence of conclusive data. The potential effects
of post-combustion ammonia injection on plume sulfate formation deserve special attention.
Table 6-2 shows that the incremental emissions of all pollutant classes except nonsegregat-
ing trace metals have either intermediate or high potential impact when applying N0x controls to IC
engines. Of primary concern are increased CO, vapor phase hydrocarbons (HC), and particulate
(smoke) emissions. Of lesser concern are sulfates, organics, and segregating trace metals from
engines burning high sulfur diesel fuels.
Similarly, N0X controls applied to gas turbines can be expected to adversely affect all in-
cremental emissions except nonsegregating trace metals, as Table 6-3 indicates. Again, increased
sulfate, particulate, organic, and segregating trace metals are of some concern in those sources
firing high-sulfur diesel fuels. If residual oil firing in gas turbines increases, these concerns
could become more serious. Presently, this appears unlikely due to materials problems, e.g., sul-
fidation with residual oils.
The incremental emission evaluations of Tables 6-1 through 6-3 are not intended to signify
any potential for adverse environmental impact. Rather, the evaluation notes source/control/
pollutant combinations for which emissions may increase due to the use of N0X controls. Evaluation
of potential adverse impact requires comparison of the source-generated, ambient pollutant concentra-
tion with an upper limit threshold concentration of the pollutant based on health or ecological ef-
fects. This comparison will be made in detail later in the program. Prior to that, some conclusions
may be drawn on the results in this section.
6-5
-------
In general, the data on incremental multimedia emissions due to N0X controls are very sparse.
More data are available for flue gas emissions than for liquid or solid effluent streams. Even so,
the only data which allow quantified conclusions are for emissions of criteria pollutants from the
major source/control combinations. Data on sulfates, trace metals and organics (POM) are sparse,
experimentally uncertain, and highly dependent on fuel properties. Incremental emissions from liquid
and solid effluent streams and during transient or nonstandard operation are almost nonexistent.
Because of this, they have generally been excluded in the present evaluation. Test data from on-
going related programs and from the N0X E/A test programs will be needed before the incremental
emissions and impacts can be evaluated for other than flue gas emissions during standard operation.
Emissions of CO, HC, particulate (smoke) and S03 with or without N0X controls have been con-
strained in the past for operational reasons rather than environmental impact. CO, HC and smoke
emissions reduce efficiency and may present a safety hazard. SO-j leads to acid condensation and
corrosion. All of these emissions are sensitive to combustion process modifications for N0X con-
trol. With the exception of SOj, incremental emissions tend to increase with N0X controls, par-
ticularly low excess air and off-stoichiometric combustion. Development experience has shown,
however, that with proper engineering these emissions can generally be constrained under low-NOx
conditions. This is particularly true for factory-installed controls on new equipment. In this
case, the flexibility for applying N0X controls with minimal adverse impact is greater than for
retrofit on existing equipment. In light of this situation, incremental emissions of criteria
pollutants are seen more as a constraining criteria to be addressed during control development
than as an immutable consequence of low-NOx firing. Moreover, the constraint on emissions for
satisfactory operational performance is generally more stringent than the constraint for acceptable
environmental impact. The environmental constraints will be carried through the N0X E/A impact
assessments for all potentially significant pollutants, but they will need to be supplemented by
operational constraints in some cases.
The situation for other flue gas pollutants is more uncertain. There is concern that con-
ventional combustion process modifications low excess air, off-stoichiometric combustion, flue gas
recirculation will increase emissions of sulfates, organics and segregating trace metals from
sources firing coal or residual oil. It should be noted, however, that this conclusion is based on
sparse data or, lacking that, on fundamental speculation. Clearly, more data are needed. Little
is known on whether these emissions can be suitably constrained to acceptable levels during control
development.
6-6
i
-------
With the firing of clean fuels - natural gas and distillate oil - the main noncriteria pol-
lutant class of concern is organics. This fact will make the testing and assessments of clean fuel
sources warm air furnaces, gas turbines, IC engines simpler than for boilers and process fur-
naces firing residual oil or coal. Additionally, the clean fuel sources have no liquid or solid
effluent streams. These considerations do not imply a priori that gas- or distillate oil-fired
equipment are more environmentally sound. Rather, the clean fuel sources can be assessed to the same
level of detail as other sources for less effort.
In conclusion, there is reasonable concern that N0X controls will increase incremental emis-
sions of some pollutants. More data are needed to determine if incremental emissions have a sig-
nificant environmental impact and to suggest corrective action if needed.
6-7
-------
SECTION 7
ENVIRONMENTAL ASSESSMENT PRIORITIES
The NOx E/A program priorities summarized In this section relate directly to the needs and
approach discussed in the Preface and Introduction of this report. The needs to be addressed by the
N0x E/A are:
Assess current and impending combustion modification applications to quantify environ-
mental, economic and operational impacts
Assess emerging advanced technology to guide control development
- Identify potential adverse impacts which should be addressed in the control develop-
ment program
- Estimate which controls will be needed and are most effective to attain air quality
goals to the year 2000
The approach used in the N0X E/A to address these needs gives primary emphasis early in the program
to assessing current and impending control applications. Assessment of advanced technology applica-
tions will proceed at a lower level of effort early 1n the program but will be emphasized toward the
end of the program. During the program, separate process engineering/environmental assessment re-
ports will be generated for each major equipment category. These reports will focus mainly on cur-
rent technology since it is more timely from an environmental standpoint and since it has been more
extensively tested. The final report will document the assessment of far-term applications and will
update the earlier assessments of near-term applications.
To support this approach, preliminary priorities are needed for:
The sequence 1n which the major source categories are to be assessed and the level of
effort devoted to each
The near-term source/control applications to be assessed
The source/control combinations to be addressed in the assessment of far-term applications,
e.g., those likely to see application 1n this century
7-1
-------
The effluent stream/pollutant combinations to be emphasized in the test programs and
assessments
In this report the preliminary source/control screening is conducted independently of the
pollutant screening. Initially the source/control combinations are screened on the basis of signifi-
cant near-term or far-term application. Pollutants for the resultant source/control combinations
are then screened for potential adverse'impacts. The results are then combined to set program
priorities.
The earlier sections of this report summarized most of the information required to deter-
mine these four priorities. This section consolidates that information and adds estimates of near-
and far-term source/control requirements to attain and maintain air quality. The priorities were
then set in the sequence of the above list. The criteria used are listed below; supporting sections
are indicated in parentheses.
Source Priorities
Current and projected use of specific equipment design/fuel combinations within a source
category (Section 2)
Extent of current or impending N0X regulations for the source category (Section 4)
ซ Ranking of source N0X emissions on a national basis (Section 5)
Relative potential for adverse environmental Impacts (Section 6)
Current and projected effectiveness of the source In urban N0X abatement (Section 7.1)
Near-Term Source/Control Priorities
Extent of use and effectiveness of controls for the source category (Section 4)
Near-term need for and effectiveness of specific source/control combinations 1n urban
N0X abatement (Section 7.1)
Far-Term Source/Control Priorities
Trends in source use (Section 2)
Developmental status and effectiveness of emerging technology (Section 4)
Far-term need for specific source/control combinations 1n urban areas for various con-
trol strategy options (Section 7.1)
7-2
-------
Effluent Stream/Pollutant/Impact Priorities
Baseline uncontrolled emissions (Section 5)
Incremental emissions due to N0X controls (Section 6)
Established limits on ambient pollutant concentrations (Section 3)
Where possible, these criteria were quantified. It was not attempted at this stage, however, to
carry a rigorous quantification through to numerical weighting of priorities. This is because the
combined effects of the general lack of data, the early stage of the program, and the general uncer-
tainty in the national N0X abatement strategy make such an approach unproductive. The qualitative
priorities that are set will be updated and reevaluated as new data become available and results of
supporting program tasks are completed.
7.1 EVALUATION OF ngx CONTROL REQUIREMENTS
The source/control priorities within the N0X E/A are largely dependent on the extent to which
specific sources will need to be controlled in this century to meet N02 air quality standards.
To aid in setting these priorities, a preliminary screening model was developed to relate ambient
air quality to several scenarios on source growth, control implementation and regulatory policy.
The key features of the preliminary screening analysis are as follows:
Use of the Modified Rollback Model (MRM) with provisions for variable source weighting
factors
c Consideration of the Los Angeles AQCR (mobile dominated) and the Chicago AQCR (stationary
dominated)
Use of NEDS AQCR emission inventories, with some modifications, together with projections
of fuel and equipment use and emissions to the year 2000; development of alternate growth
scenarios based on high and low mobile/stationary growth
Consideration of alternate base year (1972) N02 ambient concentrations in the MRM to
account for discrepancies 1n air quality data
Use of N0X control effectiveness, cost and projected availability based on the controls
characterization summarized in Section 4
This preliminary screening model was used only for the present purposes of setting priorities. Sub-
sequently In the program, a more refined air quality model accounting for source dispersion and N02-
oxldant chemistry will be used.
7-3
-------
The results of the preliminary screening analysis for the Los Angeles AQCR are shown on Table
7-1. Here, the nominal growth case assumes moderate growth for stationary and mobile sources and
use of a 0.62-g IW^/km (1-g/mile) mobile source emission standard beyond 1980. The low mobile
case assumes use of the statutory mobile source standard, 0.25 g N02/km (0.4 g/mile) beyond 1981.
Two values of the base year ambient N02 concentrations were used: 132 pg/m3 and 160 ug/m3. These
values represent the lower and upper limits of reported maximum annual averages from various moni-
toring stations and for several different four-quarter averaging periods. The source weighting
factors for power plants (PP) and mobile sources (M) were varied to show the sensitivity of the re-
sults to assumptions on dispersion of N0X from tall stacks relative to ground level sources.
The results on Table 7-1 are presented in terms of control requirements in 1985 and 2000.
The control groups cited on the table refer to the ranking shown on Table 7-2. Here the control
techniques are ranked on the basis of cost effectiveness in improving air quality. The negative
costs indicate a net cost savings due to improvements in fuel consumption efficiency. The most ob-
vious conclusion from Table 7-1 is that the control level required is dominated by the assumptions
on mobile source emissions. This is not really surprising since mobile sources accounted for
66 percent of the N0X emissions in 1973. In the low mobile case the combination of low growth (1
percent per year) and stringent controls (0.25 g/km in 1981) results in a 63-percent reduction in
mobile emissions in 1985 and a 66-percent reduction in 20QQ. This more than offsets the growth in
stationary sources and results in a net reduction in total emissions of 36 percent and 38 percent,
respectively. This level of reduction is enough to achieve the ambient standard except in the 160
yg/m3 base year case. Even in the nominal mobile case, a slight increase in the weighting of the
mobile sources has significant impact in 1985.
In contrast to the low mobile cases, maximum control is needed for all^ other cases in 2000,
and also for the high base year ambient concentration case in the near term (1985). Both of these
are again consequences of the dominance of the mobile sources - control of the stationary sources
cannot yield sufficient emission reduction to offset growth and the large mobile source emissions
contribution.
These results strongly suggest that all possible stationary source control methods may need
to be developed. According to the results discussed above, which admittedly are based only on N02
ambient goals, a less vigorous approach could be justified only if aTX of the most favorable assump-
tions were valid (i.e., low base year concentration, low mobile growth, strict and effective mobile
control, and validity of the higher mobile weighting assumption). It is unreasonable to expect that
all of this will happen and imprudent to plan control development on such an assumption. For the
7-4
-------
TABLE 7-1. SUMMARY OF CONTROL LEVELS REQUIRED TO MEET N02 STANDARD IN LOS ANGELES, AQCR 024
a
cji
Case
BYR = 132 yg/m3
BYR = 160 yg/m3
PP = 1.0
MS = 1.0
PP = 0.7
MS = 1.2
PP = 1.0
MS = 1.0
PP = 0.7
MS = 1.2
Nominal Growth
0
3
^V
Low Mobile
0
0
^0
2^"
0
^0
High Stationary
0
3
^V
V
0 No additional control required
1 Controls from Group I
2 Controls from Groups I and II
3 - Controls from Groups I, II, and III
V Violation of NAAQS, insufficient controls to meet ambient
standard
1985
2000
PP Power plant weighting factor
MS Mobile source weighting factor
BYR Base year ambient concentration for calibration
-------
TABLE 7-2. CONTROL PRIORITIZATION FOR LOS ANGELES
(2000, EQUAL SOURCE WEIGHTING)
Cost Per Unit
Rank Source/Control Change in Air Quality % Red/Unit
106$/{ug/m3)
II <
III
1
RES. FURN MEW BURNER
-15.4
40
2
SM COMM FURN NEW 0.
-14.6
40
3
IND (WTB) LEA
-13.9
7
4
SM COMM FURN A.D. #1
-12.7
60
5
COMM/INST FURN A.D. #2
-13.3
80
6
RES. FURN A.D. #1
-11.4
60
7
RES. FURN A.D. #2
-11.3
30
8
IND (FTB) LEA
- 3.67
17
9
SM PP LEA+OSC
1.57
45
10
IC ENGINES ADJ A/F
2.18
30
11
aMED PP TO 250 PPM
2.43
16
12
IC ENG.-NEW ADJ A/F
2.48
11
13
IC ENG.-NEW A.D.
0.305
51
14
aLA PP TO 250 PPM
2.50
16
15
SM PP LEA+OSC+FGR
2.74
58
16
IC ENGINE-EGR
4.10
20
17
aCCGT-NEW-H20 INJ
4.13
30
18
CCGT-NEW A.D. #1
3.38
50
19
CCGT-NEW A.D. #2
3.94
75
20
IND (WTB) LEA+OSC
5.00
17
21
IND (FTB) LEA+FGR
6.57
40
22
LA PP C.M.+NH3 INJ
6.74
79
23
MED PP C.M.+NH3 INJ
7.59
79
24
SM PP C.M.+NH3 INJ
8.25
79
25
IND (WTB) C.M.+NH3
13.4
42
aRequired to meet present legislated emission levels.
A.D. Advanced design
C.M. - Combustion modifications (LEA, OSC, FGR)
COMM - Commercial
CCGT - Combined cycle gas turbine
EGR - Exhaust gas recirculation
FGR - Flue gas recirculation
FTB Firetube boiler
FURN Furnace
H20 INO - Water Injection
I, IND - Industrial
INST - Institutional
LA - Large
LEA - Low excess air
MED - Medium
OSC - 0ff-sto1ch1ometric combustion
PP - Power plant
RES - Residential
SM - Small
WTB - Watertube boiler
7-6
-------
short term, the current combustion modification control technology might be sufficient if a favorable
mobile situation exists. For the longer term, however, all the advanced control methods presently
considered should be pursued, including ammonia injection, and research on even more effective
methods seems justified.
The results for Chicago are shown in Table 7-3. The corresponding control rankinq is qiven
on Table 7-4. Control of stationary sources is required in all cases except for 1985 if the base
year (1973) concentration of 96 ug/m3 is appropriate. The principal reason for this (no control in
1985) is that the reduction in mobile source emissions* counterbalances the growth in stationary
sources. For example, in the nominal growth case, mobile source emissions in 1985 are 123 Gg below
their 1973 level; whereas, stationary sources have increased by only 112 Gg. In the high stationary
growth case, however, an increase of 154 Gg for stationary sources in 1985 is enough to require a
small amount of control. Even with the low base year concentration, the complete range of combus-
tion modification controls is needed in the year 2000. For the high base year concentration cases
combustion modifications and ammonia injection are not always sufficient, and even in the low mobile
case combustion modification controls are needed. (The 1973 mobile emissions constitute 38 percent
of the total; consequently, mobile emissions are not as dominant as in Los Angeles.)
The conclusions for the Chicago AQCR are essentially the same as for Los Angeles. For the
long term all combustion modifications will be required and, in some cases, will not be sufficient
to meet the annual standard. In the short term, combustion modifications are needed unless the low
base year concentration is valid.
These conclusions can be qualitatively extended to many of the regions identified as Priority
AQCRs and AQMAs. Those that are heavily mobile dominated will respond to stationary source con-
trol in much the same manner as Los Angeles. It is quite likely that for these AQCRs, mobile
source controls (0.62 g/km) would be sufficient for the short term; however, combustion modifica-
tions on stationary sources would be required in the long term. The stationary source dominated
AQCRs, particularly those in the upper half of Table 7-2, will likely require combustion modifica-
tions, and perhaps ammonia injection, in both the near term and far term. It should be emphasized
that the present analysis focuses on control requirements to maintain the current annual average N02
NAAQS (100 yg/m3). The control requirements to attain alternate potential standards, e.g., short-
term N02 standard, will be evaluated later in the N0X E/A program. The results of this evaluation
could show additional control requirements over those identified here.
Mobile source emissions in 1985 are reduced by 50 and 57 percent of the 1973 level for the nominal
and low mobile cases, respectively.
7-7
-------
TABLE 7-3. SUMMARY OF CONTROL LEVELS REQUIRED TO MEET N02 STANDARD IN CHICAGO, AQCR 067
**4
f
00
BYR = 96 yg/m3
BYR = 120 yg/m3
Case
PP = 1.0
MS = 1.0
PP = 0.5
MS = 1.2
PP = 0.2
MS = 1.0
CO -o
II If
o o
PP = 0.5
MS = 1.2
PP = 0.2
MS = 1.0
Nominal Growth
^0^
^0^
2
3
Low Mobile
0
0
0
1
2
High Stationary
i
^^3
3^"
V
0 No additional control required
1 Controls from Group I
2 - Controls from Groups I and II
3 - Controls from Groups I, II, and III
V - Violation of NAAQS, insufficient controls to meet ambient standard
1985
2000
PP Power plant weighting factor
MS - Mobile source weighting factor
BYR Base year ambient concentration for calibration
-------
TABLE 7-4. CONTROL PRIORITIZATION FOR CHICAGO
(2000 EQUAL SOURCE WEIGHTING)
II
III
Cost Per Unit jg
Rank Source/Control Change in Air Quality % Red/Unit
106$/(|jg/m3)
1
RES. NEW BURNER
-43.8
40
2
RES. FURN A.D.#1
-40.2
60
3
RES. FURN A.D.#2
-38.3
80
4
SM COMM FURN NEW D
-20.5
40
5
SM COMM FURN A.D.#1
-18.6
60
6
SM COMM FURN A.D.#2
-19.7
80
7
IWTB-OIL LEA
- 3.98
6
8
N IWTB-C LEA
- 3.47
12
9
N IWTB-0 LEA
- 2.94
10
10
IWTB-COAL LEA
- 2.62
10
11
PP-OIL LEA
- 0.923
16
12
N IFTB-0 LEA
- 0.673
17
13
IFTB-OIL LEA
- 0.408
17
14
PP-COAL LEA
- 0.397
11
15
N PP-C LEA+OSC 1982
0.294
14
16
N PP-C A.D.#2 1987
0.335
43
17
PP-COAL LEA+OSC
0.709
22
18
N IFTB-0 LEA+FGR
0.789
40
19
N IWTB-0 LEA+OSC
0.821
20
20
N IWTB-0 A.D.#2 1983
0.712
50
21
N IWTB-C LEA+OSC
0.918
24
22
N IFTB-0 A.D.#2 1985
1.01
67
23
PP-OIL LEA+OSC
1.04
45
24
IWTB-COAL LEA+OSC
1.76
20
25
N IWTB-C A.D.#1 1985
1.79
40
26
IFTB-OIL LEA+FGR
1.94
40
27
PP-OIL LEA+OSC+FGR
1.97
58
28
IWTB-OIL LEA+OSC
2.39
17
29
IWTB-COAL C.M.+NH3
4.29
60
30
PP-COAL C.M.+NH3
4.51
55
31
N PP-C A.D.#2+NH3
4.56
71
32
N IWTB-0 A.D.#2+NH3
5.22
75
33
PP-OIL C.M.+NH3
5.25
79
34
N IWTB-C A.D.+NH3
6.14
70
35
IWTB-OIL C.M.+NH3
6.46
58
36
G.T. (PEAK) H20 INJ
11.16
30
N - New
C - Coal
0-011
A.D. - Advanced design
C.M. - Combustion modifications (LEA, OSC,
COMM - Commercial
CCGT - Combined cycle gas turbine
EGR - Exhaust gas recirculation
FGR - Flue gas recirculation
FTB - Firetube boiler
FURN Furnace
H20 INJ - Water injection
I, IND - Industrial
INST - Institutional
LA - Large
LEA - Low excess air
MED - Medium
OSC - 0ff-stoich1ometric combustion
PP Power plant
RES Residential
SM - Small
WTB - Watertube boiler
7-9
-------
The conclusions for the required control levels for both Los Angeles and Chicago are very
similar to those of other studies, for example, the DOT study (Reference 7-1) and an EPA study (Ref-
erence 7-2). Both of these studies reported that neither Los Angeles nor Chicago could achieve the
ambient standard with even maximum stationary source control and 0.25 g/km mobile controls. The re-
sults here indicate that it may be possible in favorable circumstances. The primary differences be-
tween the present analysis and the two cited above are in the growth rates and the base year ambient
levels for which the models were calibrated. The DOT study allowed stationary sources to grow at
3.9 percent per year. The EPA study considered 5 percent per year growth and a base year concentra-
tion of 182 vg/m1- Because of growth restrictions in Los Angeles an effective annual growth of about
1 percent per year for the aggregate of the stationary sources was used in this work. In Chicago,
electric power plant growth was much less than 3.9 percent, primarily because of growth in nuclear
capacity. These factors account for the difference between never meeting the standard and possibly
meeting the standard. These differences also help to illustrate the Influence of the basic assump-
tion (growth rate, base year concentration, and source weighting factors) on the quantitative results.
However, the qualitative conclusions, stated below, remain the same.
The conclusions of this portion of the analysis can be summarized as follows:
NO^ controls for residential furnaces and small commercial furnaces yield substantial
reductions in fuel use and can significantly effect the break-even point in the cost for
stationary source control strategies
The order in which controls should be implemented is significantly influenced by the fuel
savings features of the control method and, of course, the availability of the technology
For the short term, combustion modifications for stationary sources will be needed for
most of the priority AQCRs. Both retrofit and "new design" controls should be developed -
particularly those that also result in an energy savings.
For the long term, all combustion modifications and ammonia Injection will be required.
This may be the case even for the minimum mobile source emissions case (low growth
0.25 g/km).
7.2 SUMMARY OF SOURCE/CONTROL PRIORITIES
This section combines the results of Section 7.1 with those of other sections to set N0X E/A
program priorities on sources and source/control combinations. The source priorities will be used
to determine the order in which the process engineering and environmental assessment studies will be
conducted for the major source categories (utility boilers, industrial and commercial boilers, gas
7-10
/
-------
turbines, commercial and residential warm air furnaces, IC engines and industrial process combustion
equipment). The source priorities will also guide the level of effort to be devoted to the study of
each major source category and to individual design types within the category. These studies will
focus primarily on near-term source/control applications; far-term application of emerging technology
will be studied later 1n the program. The source/control priorities will be used to determine which
source/control combinations will be given major or minor emphasis 1n the near-term process studies
and which will be emphasized in the far-term studies. The source/control priorities will also guide
the field test program. Other factors such as site availability and the potential for teaming ar-
rangements will also have a significant role in the test priorities.
The source prioritization used the following sequence:
Subdivide major source categories (utility boilers) into source/fuel categories (coal-
fired utility); further subdivide to major design types (tangential) likely to be exten-
sively controlled for N0x, and minor design types (vertical) not likely to be extensively
controlled due to dwindling use and/or lack of control flexibility
Assess the extent to which controls are in use or are planned for each source/fuel cate-
gory
Rank source/fuel categories on basis of nationwide mass emissions of N0X
Assess the relative baseline environmental impact potential for each source/fuel category
Identify the relative effectiveness of near-term and far-term source control implementa-
tion in maintaining air quality in urban areas
Table 7-5 summarizes the results of this prioritization sequence. The prioritization 1s largely
qualitative due to the uncertainty and lack of data In these areas. The considerations which were
made in constructing Table 7-5 are summarized below.
Source Categorization
The division of the source/fuel category Into major and minor design types used the results
of Section 2 of this report. The major design types are those, which 1n the near-term, will be
subject to N0X controls. The designation "major" implies a design type will be given primary empha-
sis in the process studies and is a candidate for the field test program. The minor design types
are either obsolete or difficult to control or otherwise unlikely to be subject to significant NO
controls In the near term. The minor design types will be given secondary emphasis in the process
studies and will not be candidates for field tests. It should be noted that minor design types are
7-11
-------
TABLE 7-5. EVALUATION OF NOx E/A SOUPXE PRIORITIES
Source Category
Major
Design Types
In E/A Program
Minor
Design Types
1n E/A Program
Degree of
Control
Implementation
Nationwide
NO. Emission
Ranking
Relative
Impact h
Potential
Source
Need/Effe
Near term
Control .
:t1veness
Far term
Source
Ranking
in E/A
Proqram
Coal-fired utility
Tangential,
single and
opposed wall-
flred, turbo
Cyclone,
vertical,
stoker
All new sources, moder-
ate for existing sources
1
H
H
H
1
011-flred utility
Same as above
Cyclone
Extensive for existing
sources
4
M
H
L
3
Gas-fired utility
Same as above
Same as above
3
L
H
I
3
Coal-f1red watertube
Pulv. Stoker-
spreader
Underfeed/
overfeed
Low for existing,
impending for new
5
H
H
H
2
011-flred watertube
Single and
multlburner
Same as above
10
M
H
H
6
Gas-fired watertube
Single and
multlburner
Same as above
7
L
H
M-L
11
Coal-fired flretube
Stoker
Same as above
14
H
M
L
14
011-flred flretube
Scotch
Firebox, HRT
Same as above
6
M
H
H
5
Gas-fired flretube
Scotch
Firebox, HRT
Same as above
9
L
H
M-L
12
Gas- and oil-fired
gas turbines
Industrial,
utility,
sinple cycle
Comh. cycle
repowerlng
Moderate for existing
sources, intending for
new sources
11
L
H
H-M
4
Gas- and oil-fired
warn air furnaces
Res., Conn,
furnace
Space
heaters
Increasing use for
energy conservation
12
L-H
H
H-M
7
Compression ignition
IC engines (dlesel
fuel and mixed)
Turbocharged
Blower
scavenged
Negligible for existing
sources; impending for
new sources
8
L-M
H
M-L
10
Spartc ignition
IC engines
Turbocharged
naturally
aspirated
Same as above
2
L-M
H
M
9
Industrial process
combustion
Process heat-
ers, furnaces,
kilns
Negligible
13
M-H
K
M-H
13
aMajor refers to sources likely to be controlled for NOx; minor refers to sources for which controls are unlikely to be Implemented In the near tern.
" high; M " medium; L ป low
-------
not necessarily insignificant sources of N0x- For example, cyclone boilers emit 8 percent of sta-
tionary source N0x and rank fourth among all stationary source design/fuel combinations (see Table
5-3). Yet, the cyclone combustion characteristics make them very difficult to control for N0X-
Their sale has been discontinued for other than high sodium lignite applications and 1t 1s unlikely
many existing units will be controlled for N0x> Other considerations made 1n the source categori-
zation are as follows:
Vertical- and stoker-fired utility boilers are obsolete; although they are amenable to
some control, the current application is Insignificant
Firebox and horizontal return tube package firetube boilers are dwindling in use in favor
of the scotch design; the vast majority of new sales to meet the planned N0X standard
will be of the scotch design
t Firetube stokers are dwindling in number due to cost
The use of N0X controls on space heaters in the near term is unlikely
Insufficient data are available to divide industrial process combustion equipment into
major and minor design types
The growth projection and design trends for this prioritization are preliminary. They will be
studied in greater detail later and Table 7-5 will be updated as necessary.
Control Implementation
The Information for the "Degree of Control Implementation" column on Table 7-5 1s taken from
Section 4. Since the assessment of current controls application is a major objective of the N0X E/A,
the degree of control Implementation is a dominant criterion 1n setting source priorities. To date,
the vast majority of stationary combustion source NC>X controls has been on utility boilers. Gas and
oil units have been the most extensively controlled, but an Increasing number of standards has been
set recently for coal units. No new gas- or oil-fired units are being sold, so N0x controls for coal
units via the New Source Performance Standards (NSPS) will dominate 1n the future. Other sources with
current control applications are large Industrial boilers and gas turbines. NSPS are also planned
for these sources along with IC engines. The lead time for Implementing the standard and delivering
new unit orders is typically several years. Thus, the degree of control application for these sources
will not be comparable to that for utility boilers in the near term. This fact alone 1s sufficient to
rank utility boilers as the top priority in the N0X E/A.
7-13
-------
Nationwide Emission Ranking
The ranking of design/fuel types by nationwide mass emissions of N0x is given in Table 5-3.
These results have been consolidated on Table 7-5 for the specific source categories listed there.
Nationwide mass emissions are useful for weighting relative emission contributions of various sources
and detecting emission trends independent of local variations. They are used within the EPA to set
priorities on emission standards. Use of nationwide emissions does suffer a drawback, however, in
that it does not account for variations among source categories in proximity to population centers
and variations in regional use of specific source/fuel types. These factors were qualitatively
included in the relative impact potential column. These factors will be quantified later in the
N0x E/A and used for a formal ranking of sources according to pollution potential.
Relative Impact Potential
The ranking of sources by relative impact potential was based on the multimedia emissions
inventory of Section 5 and the evaluation in Section 7.3 of potential adverse impact of these emis-
sions. Although impacts due to N0X controls were not considered in the evaluation, the results >of
Section 6 were useful in relating design type and fuel to potential for emissions of specific pol-
lutants (e.g., organic emissions from IC engines) where emission data were sparse. Additionally,
the proximity of specified sources (e.g., residential furnaces) to populated areas was also consid-
ered. As shown on Table 7-5, the relative Impact potential resulting from the above considerations
was generally high for coal firing, medium for residual oil firing, and low with the firing of clean
fuels. The borderline L-M for residential furnaces resulted from the proximity of these sources to
populated areas and the potential for increased emissions during cycling transients. IC engines were
also a borderline case. Even though they fire clean fuels, the emissions of organics are much higher
than for other sources. Little emission/impact data are available for industrial process furnaces.
They were rated M-H on the basis of fuel use.
Effectiveness of Source Control in Air Quality Maintenance
This criterion was based on the results of the air quality screening analysis discussed in Sec-
tion 7.1. Separate consideration was given to near-term effectiveness and to far-term effectiveness
in order to isolate effects of design trends and growth projections for source categories. The anal-
ysis 1n Section 7.1 showed that the need for bringing specific source categories under control 1s
highly uncertain. The estimated control needs were found strongly dependent on growth projections,
assumptions on future mobile source control, measurements of ambient concentrations of N02, and the
relative weighting of the NO^ air quality Impact emissions from point sources (power plants) and
ground level sources (mobile sources). These factors are all in a state of flux. Assuming optimistic
7-14
-------
resolution of these factors (In terms of stationary source air quality impact), only moderate control
of major stationary sources will be needed in the near term (1985). Assuming moderate or pessimistic
resolution of these factors, however, implies the need for extensive near-term control of stationary
sources. In the far term (2000), extensive control 1s generally needed regardless of assumption.
For purposes of setting priorities in the N0X E/A program, the estimated control needs for moderate or
pessimistic assumptions are used. This 1s because the N0X E/A 1s largely a problem definition study
and its purposes would not be served by using optimistic assumptions on the potential for adverse
impact. For the moderate or worst case scenarios, the estimated near-term control needs, as shown
on Table 7-5, are generally high for all source categories. For the far term, the needs are focused
on extensive control of new sources. Thus, sources with dwindling new sales due to design trends or
fuel availability are derated in the far term. As expected, the trend is for increasing use of coal
and oil and decreasing use of gas. The projected availability of clean fuels for industrial sources
and gas turbines will be examined in more detail later in the program.
It should be noted that control requirements are estimated only for compliance with the cur-
rent annual average National Ambient Air Quality Standard (100 pg/m3). Additional controls may be
needed if a short-term N02 standard is set based on the mandates of the 1977 Clean Air Act Amendments.
Overall Source Ranking
The final column on Table 7-5 gives a qualitative ranking of the 13 source/control categories.
In deciding this ranking, the degree of control implementation and the relative impact potential were
given the most weight. Based on this ranking, the process and environmental assessment studies in
the N0X E/A will be conducted in the following sequence:
1. Utility and large industrial watertube boilers
2. Industrial and commercial packaged boilers
3. Gas turbines (simple cycle and combined cycle)
4. Residential and comnerclal warm air furnaces
5. Reciprocating internal combustion engines
6. Industrial process combustion equipment
Within each of these studies, the relative effort for specific source/fuel categories will follow
the order of ranking of Table 7-5.
The source prioritization discussed above 1s extended on Table 7-6 to Include consideration
of specific source/control combinations. The table shows which source/control combinations are to re-
ceive major or minor emphasis 1n the six process studies of near-term applications listed above.
7-15
-------
TABLE 7-6. SUMMARY OF NOx E/A SOURCE/CONTROL PRIORITIES
Source
Ranking
NEAR TERM EFFORT IN E/A PROGRAM:
CURRENT AND IMPENDING APPLICATIONS
FAR TERM EFFORT IN E/A PROGRAM:
ADVANCED TECHNOLOGY
Source
Major Emphasis -
Sources4
Major NO, E/A
Emphasis - Controls
Minor N0X E/A
Emphasis - Sources
Minor NO. E/A .
Emphasis - Controls
Major
Emphasis
Mi nor
Emphasis
1
( Coal-fired utility
I boilers, existing
Tangential, opposed i
single wall, turbo-fired
LEA, BBF, BOOS, OFA,
low-NOx burners
Cyclone, vertical
stoker
FGR, RAP, H2O inj.,
load reduction,
NH3 injection
NH3 injection
1 Coal-fired utility
( boilers, new
Same as above
LEA S OFA; low-NO*
burners, enlarged
fi rebox
FGR, RAP, H^O inj.,
NH3 injection
Advanced OFA
techniques;
adv. low-NOx
burners, NH3
injection
Flue gas
treatment;
fluidized
beds; adv.
cycles
3, 6
011-fired, gas-
fired utility
boilers
Same as above
LEA, BBF, BOOS. OFA.
FGR
Cyclone
RAP, H2O Inj., NH3
Injection
Advanced low-
NOx burners,
NH3 inj.
Chemically
active
fluid bed
2
, Coal-fired water-
( tube. Industrial -
1 pulverized
Single or multiburner
wall-fired
LEA. BBF, BOOS. OFA,
low-NOx burners
Load reduction
Advanced low-
NOx burners,
advanced OFA.
NH3 injection
f Coal-fired water-
' tube Industrial -
stoker
Spreader
LEA, OFA
Underfeed/overfeed
Factory
installed
OFA. NH3 inj.
-
6, 11
011-flred, gas-
fired watertube
Single or multiburner
wall-fired
LEA. OFA, low-NOx
burners
Load reduction
Adv. low-NOx
burners, adv.
OFA, NH3 inj.,
alt. fuels
14
Coal-fired fire-
tube stoker
Firebox, horizontal
return tube
LEA
5. 12
Oil-fired, gas-
fired firetube
Scotch
LEA, FGR. OFA, low-
NOx burners
Firebox HRT
Load reduction
Adv. low-NOx
burners, adv.
OFA, alt. fuels,
catalytic comb.
4
Gas- & oil-fired
gas turbines
Utility, Industrial
slnple cycle
Water injection
Combined cycle,
repowering
Can modifications
Adv. can design,
comb, cycles,
alt. fuels,
catalytic comb.
7
Gas- ( oil-fired
warn air furnace
Residential, commercial
furnaces
Low-NOx burners
Space heaters
Adv. burner/
firebox des.,
alt. fuels,
catalytic comb.
9
Spark Ignition IC
engines
Turbocharged, natural-
ly aspirated
Operational tuning,
reduced inlet air
temperature
EGR, derate
Chamber redesign,
alt. fuels
Exhaust
gas
treatment
10
Compression igni-
tion IC engine
(diesel, mixed fuel
Turbocharged
Operational tuning
Blower scavenged
Derate
Chamber redesign
alt. fuels
13
Industrial process
combustion
Process heaters,
furnaces, kilns
LEA, load reduction,
RAP, FGR, H20
injection
Low-NOx burners
Low-NOx burn-
ers , OFA,
alt. fuels
at1ajor refers to sources or controls emphasized in near term control programs; minor refers to sources or controls less likely to be usea.
bLEA. - low excess air-. BBT - biased burner firing; BOOS - burners out of service; OFA = overfire air; FGR = flue gas recirculation; RAP ~ reduced air preheat
-------
The table also shows preliminary selection of which advanced source/control combinations will be
evaluated In the later study of far-term applications. The prioritization of current technology
was based directly on the Information 1n Section 4 (see Tables 4-2 and 4-3). The prioritization
considered the extent of current applications of specific source/control combinations and the cost
effectiveness of a given control compared to competitive techniques. Major emphasis will be given
to the majority of source/control combinations likely to see significant control in the next 5
years. The selection of advanced techniques for study 1n the far-term effort was also based on Sec-
tion 4. The developmental status and schedule as well as the potential availability of competitive
techniques were considered. The selection of advanced techniques also considered the results of
Section 7.1 which showed the need for advanced combustion modifications and, possibly, ammonia in-
jection in the 1980's and 1990's. Advanced techniques which are being covered by other assessment
efforts (e.g., fluidized beds, advanced cycles) will be given minor emphasis in the far-term effort.
7.3 POLLUTANT/IMPACT SCREENING
The source/control combinations prioritized in Section 7.2 are further evaluated here to
identify specific pollutants which may cause an adverse environmental Impact with or without N0X con-
trols. These results will be used to set priorities for the sampling and chemical analyses to be
done during the later field test programs. The emphasis in the pollutant/Impact screening is on
flue gas emissions. The data on liquid and solid effluent streams are very sparse. They will there-
fore be sampled during the test program to obtain the data needed for a pollutant/impact screening
such as done here for flue gas emissions.
The set of pollutant classes under consideration was described 1n Section 6 and Includes car-
bon monoxide, vapor phase hydrocarbons, particulates, sulfates, condensed phase organlcs, and trace
metals. Several of these classes can be further speclated Into more detailed pollutant groups, which
give a better representation of potential health/welfare hazards, as was done in Section 3. For ex-
ample, the vapor phase hydrocarbon class 1s comprised of alkanes, alkenes, alkynes, aldehydes, car-
boxylic acids, and aromatlcs. (Of course sulfates, organlcs, and trace metals are generally emitted
as particulates, but the particulates class has been separately discussed because it Is a criteria
pollutant, and because more emissions data on this class of pollutants are available.)
Baseline emissions for each pollutant species group, as a function of combustion source class,
were summarized In Section 5. In addition, Section 6 summarized the Incremental emissions of these
pollutant groups as a function of applied N0X combustion control. The health and welfare aspects
of each species/group were discussed In Section 3 1n terms of developing a set of maximum ambient
screening concentrations. By combining Information developed 1n each of those sections with a dis-
persion model (which relates ground level pollutant concentrations to single source emission levels
7-17
-------
as a function of combustion source), it is possible to flag the pollutants from each combustion
source which represent potential environmental hazards due to applying NO^ controls.
Such a summary appears in Tables 7-7 and 7-8. Table 7-7 shows baseline emissions, typical
emission levels with N0X controls, maximum ambient screening concentrations, and derived maximum
allowable emission level (from the dispersion model) for the pollutant groups under consideration.
The pollutant groups listed in Table 7-7 are those for which incremental emissions data are avail-
able. Table 7-8 shows a similar summary for those pollutants groups for which little or no field
data exist on the incremental effects of N0X combustion controls.
From the data presented in Tables 7-7 and 7-8, it is possible to identify those pollutant
groups which are emitted at levels near, or exceeding, the defined maximum allowable emission level.
For current purposes, pollutant group/combustion source combinations are flagged if emission levels
with N0x control data, or baseline emission in the absence of incremental H0X control data (Table 7-8),
exceed 10 percent of the maximum allowable level. These combinations are noted in Tables 7-7 and 7-8,
and further summarized in Table 7-9.
Table 7-9 illustrates that incremental emissions from large coal- and oil-fired boilers
potentially represent most significant environmental hazards. Baseline emissions of particulate,
sulfates, and certain POM species from this source class currently exceed the derived maximum allow-
able emissions levels, while emissions of several other POM species are within an order of magnitude
of the maximum limit. In addition, while emissions of total vapor phase hydrocarbons from large
boilers were not identified as being of concern, emissions of several hydrocarbon classes, notably
oxygenates and aromatics, were flagged. Finally baseline emissions of several trace metals from
coal- and oil-fired boilers were noted as exceeding, or falling within a factor of 10 of maximum
levels. It is interesting to note that six of the eight flagged elements exhibit Class II, or segre-
gating, behavior; they tend to repartition and concentrate in fine particulate.
Large coal- and oil-fired boilers were not the only source class associated with pollutant
streams of concern. Incremental total vapor phase hydrocarbon emissions from IC engines operating
with dry N0X controls exceeded 10 percent of maximum allowable emissions and therefore represent
another concern. In addition, baseline emissions of several organics from residential coal stokers
exceeded maximum limits. However, the use of coal firing in residential heating applications is
definitely declining, so this source/pollutant combination should not be considered a priority
concern.
Based on the information presented in Table 7-9, it is clear that further study is needed
of N0X controls which could increase emissions of:
7-18
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TABLE 7-7. COMPARISON OF POLLUTANT EMISSION LEVELS WITH NOx CONTROLS TO MAXIMUM ALLOWABLE EMISSIONS
Pollutant Class
Combustion
Source
Fuel
Maximum
Ambient
Concentration
-------
TABLE 7-8, COMPARISON OF BASELINE POLLUTANT EMISSION LEVELS TO MAXIMUM ALLOWABLE EMISSIONS
Pollutant Class/Group
Combustion Source
Fuel
Maximum
Ambient
Concentration
(ppb)
Maximum
Allowable
Emission Level
(ppm)
Baseline
Emissions
(ppm)
Concern
Flag3
Vapor Phase Hydrocarbonsb
Alkanes
4,420
Utility Boilers
Natural
, 011
Coal
Gas
54,000
<80
<15
<10
Industrial Boilers
Oil
Coal
450,000
<40
<150
Alkenes
59,500
Utility Boilers
Natural
011
Coal
Gas
725,000
<80
<15
<10
Industrial Boilers
Oil
Coal
Unl1m1ted
<40
<150
Alkynes
62,700
Utility Boilers
Natural
Oil
Coal
Gas
765,000
<5
<5
<10
Industrial Boilers
Oil
Coal
Unlimited
<5
<10
Aldehydes
2.1
Utility Boilers
Natural
Oil
Coal
Gas
25.6
5
5
<10
+
+
+
Industrial Boilers
Oil
214
2.5-200
++
Carboxylic Acids
13
Utility Boilers
Natural
Oil
Coal
Gas
159
2.5
6-12
200
++
Aromatics (benzene
0.002
and one-ring
derivatives)
Utility Boilers
Natural
Oil
Coal
Gas
0.024
<20
<30
<50
++
++
++
(mg/m3)
(g/m5)
(g/ms)
Sulfates
0.002
Utility Boilers
Natural
Oil
Coal
Gas
0.024
0
0.047
0.056
++
++
(ppt)
(ppb)
(ppb)
Orqanics (POM's)
Anthracene
0.14
Utility Boilers
Coal
1.71
0.3
+
Industrial Boilers
Oil
Coal
14.3
2
0.1-0.3
++
Residential Units
Coal
8.2
0.4-1,000
++
Phenanthrene
Utility Boilers
Coal
4,000
50,000
0.1-0.3
Industrial Boilers
Natural
Oil
Coal
Gas
420,000
0.04
0.7-3.7
0.3-3
Residential Units
Coal
240,000
9-2,300
a + denotes baseline emissions exceed 10 percent of maximum allowable level
++ denotes baseline emissions exceed maximum allowable level
Maximum ambient concentration and associated maximum allowable emission level for hydrocarbon species consider only
primary health hazards. Effects of secondary (derived) pollutants are not considered.
7-20
-------
TABLE 7-8. Continued
Pollutant Class/Group
Combustion Source
Fuel
Maximum
Ambient
Concentration
(PPt)
Maximum
Allowable
Emission Level
(PPb)
Baseline
Emissions
(PPb)
Concern
Flag*
Orqanics (POK's) (Cont.)
Fluoranthrene
Utility Boilers
Coal
10,900
133,000.
0.003-0.5
Industrial Boilers
Natural
on
Coal
Gas
1,110,000
0.04-3.4
0.02-1.8
0.8-10
Residential Units
Coal
641,000
13-350
Pyrene
0.121
Utility Boilers
Coal
1.48
0.01-0.5
+
Industrial Boilers
Natural
Oil
Coal
Gas
12.4
0.5-7.5
0.005-2.2
0.6-4.5
+
+
+
Residential Units
Coal
7.1
2-2,500
++
Benzo(a)pyrene
Utility Boilers
Coal
0.097
1.2
0.003-0.1
Industrial Boilers
Natural
Oil
Coal
Gas
9.9
0.006-0.1
0.006-0.3
0.007-2.2
+
Residential Units
Coal
5.7
0.008-800
++
Benzo(e)pyrene
0.097
Utility Boilers
Coal
1.2
0.007-0.15
+
Industrial Boilers
Natural
Coal
Gas
9.9
0.006-0.5
0.02-1.7
+
Residential Units
Coal
5.7
1-330
++
Perylene
Utility Boilers
Industrial Boilers
Coal
Coal
0.097
1.2
9.9
0.005-0.015
0.35
Residential Units
Coal
5.7
0.1-770
++
(ug/m3)
(mg/rn3)
(mg/m3)
Trace Metals
As
Utility Boilers
on
Coal
0.825
10.1
0.004
0.45
B
Oil
Coal
16.5
201
0.068
3.41
Ba
on
Coal
0.825
10.1
0.52
0.65
Be
Coal
0.0033
0.04
0.52
++
Bi
Coal
16
195
0.03
Cd
011
Coal
0.00825
1.01
0.006
0.12
+
Co
011
Coal
0.165
2.0
0.27
0.11
+
a + denotes baseline emissions exceed 10 percent of maximum allowable level
++ denotes baseline emissions exceed maximum allowable level
7-21
-------
TABLE 7-8, Concluded
Pollutant Class/Group
Combustion Source
Fuel
Maximum
Ambient
Concentration
(J-iQ/m3)
Maximum
Allowable
Emission Level
(mg/m3)
Baseline
Emissions
(mg/m3)
Concern
Flag3
Trace Metals (Cont.)
Cr
0.001
Utility Boilers
Oil
Coal
0.012
0.68
0.43
++
++
Cj
Oil
Coal
1.65
20.1
0.55
1.20
Hg
Oil
Coal
16.5
201
0.008
0.23
Mn
Oil
Coal
8.25
101
0.55
1.58
Mo
Oil
Coal
8.25
101
0.55
0.25
fli
0.165
011
Coal
2.0
32
0.68
++
+
Pb
0.247
011
Coal
3.0
0.62
0.59
+
+
Sb
011
Coal
0.825
10.1
0.004
0.04
Se
Oil
Coal
0.33
4.0
0.632
0.173
V
0.825
011
Coal
10.1
47.5
1 .20
++
++
Zn
1.65
Oil
Coal
20.1
0.87
9.36
+
Zr
Oil
Coal
8.2
100
0.17
0.86
a + denotes baseline emissions exceed 10 percent of maximum allowable level
++ denotes baseline emissions exceed maximum allowable level
7-22
-------
TABLE 7-9. SUMMARY OF POTENTIAL POLLUTANT/COMBUSTION SOURCE HAZARDS
Emission Exceeds
Emission Exceeds
Pollutant Class/Group
Combustion Source
Allowable
10% of Allow-
Limit
able Limit
VaDor Phase Hydrocarbons
Total
IC Engines
X
Aldehydes
Utility Boilers, all Fuels
X
Oil-Fired Industrial Boilers
X
Carboxyllc Acids
Coal-Fired Utility Boilers
X
One-Ring Aromatics
Utility Boilers, all Fuels
X
Particulates
Coal-Fired Boilers
X
011-Fired Industrial Boilers
X
Sulfates
Coal- and Oil-Fired Utility
Boilers
X
Orqanics
Anthracene
011-Fired Boilers
X
Coal-Fired Residential Units
X
Coal-Fired Utility Boilers
X
Pyrene
Coal-Fired Residential Units
X
Boilers, all Fuels
X
Benzo(a)pyrene
Coal-Fired Residential'Units
X
Coal-F1red Industrial Boilers
X
Benzo(e)pyrene
Coal-Fired Residential Units
X
Coal-Fired Boilers
X
Perylene
Coal-Fired Residential Units
X
Trace Metals
Be
Coal-Fired Utility Boilers
X
Cd
Coal-Fired Utility Boilers
X
Co
011-F1red Utility Boilers
X
Cr
Coal- and Oil-Fired Utility
Boilers
X
Ni
011-Fired Utility Boilers
X
Pb
Coal- and 011-Fired Utility
Boilers
X
V
011-Fired Utility Boilers
X
Coal-Fired Utility Boilers
X
Zn
Coal-Fired Utility Boilers
X
7-23
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Particulates from coal- and oil-fired boilers, e.g., off-stoich1ometric combustion (OSC),
flue gas recirculation (FGR), and ammonia injection (NHj)
Sulfates from coal- and oil-fired boilers, e.g., OSC, FGR, and NH3
Organics from coal- and oil-fired boilers, e.g., low excess air (LEA), OSC, and FGR
ซ Segregating trace metals from coal- and oil-fired boilers, e.g., LEA, OSC, and FGR
Vapor phase hydrocarbons emissions from IC engines, e.g., all controls
7.4 FUTURE EFFORT
This report has:
1. Documented the scope of sources, pollutants, impacts, and controls to be considered in the
N0X E/A
2. Evaluated data on impact criteria, control effectiveness, baseline multimedia emissions,
and incremental impacts of N0X controls
3. Set preliminary priorities on source/control combinations and effluent stream/pollutants
to be considered
These results will serve to initiate and scope future efforts to:
Screen and rank the pollution impact potential of uncontrolled sources and effluents (Bl)
- Update the Section 5 emissions inventory
- Develop approaches to assess emissions during nonstandard operation
- Generate growth projections of source/fuel use and emissions
- Expand impact analysis of Section 7.3
Generate impact screening criteria for Bl and B5 assessments (B2)
- Coordinate with other studies developing impact criteria; finalize human health im-
pact criteria of Section 2
- Decide approach to generalize terrestrial and aquatic impacts
- Develop scenarios for alternate NOg air quality standards for the Task C air quality
modeling
Conduct field tests of priority source/control combinations (B3)
- Survey candidate test sites for coal- and o1l-f1red utility and industrial boilers
and oil-fired gas turbines using N0X controls
7-24
-------
- Finalize sampling and analysis requirements based on the E/A steering committee recom-
mendations and Section 7 results
Generate process engineering and environmental assessment reports for utility boilers (B5)
- Expand process data and control results of Sections 2 and 4
- Develop cost model to standardize control cost estimates
Develop systems analysis model with chemistry and dispersion effects (C)
- Update model Inputs with cost data from B5 and regional inventories from B1
- Expand control assessment of Section 7.1 to consider NOg-oxIdant reactions and a
short-term N02 standard
These efforts are discussed in the Introduction and Illustrated 1n Figure 1-1.
The data evaluations contained in this report have shown the strong need for setting priori-
ties 1n all areas of the program. Serious data gaps exist for baseline and controlled multimedia
emissions and impacts. These data gaps make 1t Impossible to consider to a meaningful level all
potential source/control/effluent stream/pollutant/impact combinations within the scope of the N0X
E/A. The program results will be most useful 1f the effort 1s prioritized to allow comprehensive
assessment of fewer source-Impact combinations. The prioritizations contained 1n this report have
accordingly set the emphasis of the N0X E/A as follows:
Sources: Major emphasis on stationary fuel combustion sources firing coal or residual
oil and projected to use a significant degree of N0X controls 1n the near term; less
emphasis on sources firing clean fuels; minor emphasis on sources which will not be
controlled 1n the near term
Controls: Major emphasis on most widely used current applications; less emphasis on ad-
vanced technology; minor emphasis on control techniques not widely used
Effluent Streams and Pollutants: Major emphasis on flue gas emissions during steady-
state operation; less emphasis on liquid and solid effluent streams; minor emphasis on
emissions during transient or upset conditions
Impacts: Major emphasis on human health impacts due to inhalation; less emphasis on ter-
restrial and aquatic Impacts and on human health Impacts due to ingestion via the food
chain; minor emphasis on materials Impacts
7-25
-------
REFERENCES FOR SECTION 7
7-1. "Air Quality, Noise and Health - Report of a Panel on the Interagency Task Force in Motor
Vehicle Goals Beyond 1980," Department of Transportation, March 1976.
7-2. Crenshaw, J. and A. Basala, "Analysis of Control Strategies to Attain the National Ambient Air
Quality Standards for Nitrogen Dioxide," presented at the Washington Operation Research Coun-
cil's Third Cost Effectiveness Seminar, Gaithersburg, Maryland, March 18-19, 1974.
7-26
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TECHNICAL REPORT DATA
(Please read /nwiicttons on the reverse before completing)
1. REPORT NO. 2.
EPA-600/7-77-119a
3. RECIPIENT'S ACCESSION NO.
4. title andsubtitle preiiminary Environmental Assess-
ment of Combustion Modification Techniques: Volume
I. Summary
5. REPORT DATE
October 1977
6. PERFORMING ORGANIZATION CODE
7. authoris) ฃ .Mason, A.B. Shimizu, J.E.Ferrell,
G.G.Poe, L.R. Water land, and R.M.Evans
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Acurex Corporation, Aerotherm Division
485 Clyde Avenue
Mountain View, California 94042
10. PROGRAM ELEMENT NO.
EHE624A
11. CONTRACT/GRANT NO.
68-02-2160
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Special: 6/76-2/77
14. SPONSORING AGENCY CODE
EPA/600/13
15.supplementary notes jerl-RTP project officer for this report is Joshua S. Bowen,
Mail Drop 65, 919/541-2470.
16.abstract The report. gives preliminary methodologies, data compilation, and program
priorities for assessing stationary combustion sources and NOx combustion modifica-
tion technologies. Equipment characterizations and multimedia emission inventories
are presented for utility and industrial boilers, commercial and residential warm air
furnaces , gas turbines, IC engines, industrial processes, and advanced combustion
processes. Control costs and operational, energy, and environmental impacts are
compiled and discussed for current and emerging combustion modification NOx con-
trols. Incremental emissions of CO, HC, and particulate due to NOx controls can be
minimized through control development engineering. Other effluents (POMs, segrega-
ting trace metals, and sulfates) show potential for increased emissions with some
combustion modifications. Significant data gaps in emissions and impacts of multime-
dia pollutants, with and without NOx controls, are noted. Program priorities "for
field tests and process studies to augment the data base are presented.
1?.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air "Pollution Internal Combustion
Combustion Engines
Combustion Control Operating Costs
Nitrogen Oxides Coal, Fuel Oil
E>ust Natural Gas
^oilers Organic Compounds
ฃas Turbines Inorganic Compounds
b.IDENTIFIERS/OPEN ENDED TERMS
Air Pollution Control
Stationary Sources
Combustion Modification
Emission Factors
Control Costs
Environmental Assess-
ment
e. COSaTI ) rcM Ciroup
13B
2 IB
07B
11G
13A
13G
21G
14A
07C
DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF r^..jfc5
68
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
6pA
Form 2220-1 (9-73)
7-27
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