EPA-450/2-78-005a
Electric Utility Steam Generating  Units
  Background Information for Proposed
          NOX  Emission Standards
             Emission Standards and Engineering Division
            U.S. ENVIRONMENTAL PROTECTION AGENCY
               Office of Air, Noise, and Radiation
            Office of Air Quality Planning and Standards
            Research Triangle Park, North Carolina 27711
                     July 1978

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This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers.  Copies are
available in limited quantities from the Library Services Office (MD-35),
U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina 27711; or, for a fee, from the National Technical Information
Service, 5285 Port Royal Road, Springfield, Virginia  22161.
                  Publication No. EPA-450/2-78-005a
                                ii

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                           Background Information and
                      Draft Environmental Impact Statement
                    for Proposed NO  Emission Standards for
                     Electric Utility Steam Generating Units

                         Type of Action:  Administrative

                                  Prepared by:
Don R. Goodwin
Director, Emission Standards and Engineering Division
Environmental Protection Agency
Research Triangle Park, North Carolina  27711
 August 16. 1978

     (Date)
                            Approved by:
Walter C. Barber
Director, Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina  27711
August 16, 1978

    (Date)
Draft Statement Submitted to EPA's
Office of Federal  Activities for Review on
This document may be reviewed at:

Central Docket Section
Room 2903B, Waterside Mall
401 M Street
Washington, D.C.   20460

Additional copies may be obtained at:

U.S. Environmental Protection Agency Library (MD-35)
Research Triangle Park, North Carolina  27711

National Technical Information Service
5285 Port  RoyaA Road
Springfield, Virginia  22161
September 1978

   (Date)
                                   iii

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                           TABLE OF CONTENTS
3.
 SUMMARY
 1.1  Proposed Standards
 1.2  Environmental  Impact
 1.3  Economic Impact
 INTRODUCTION
 2.1  Authority for  the Standards
 2.2  Selection of Categories  of Stationary Sources
 2.3  Procedure for  Development  of  Standards
      of Performance
 2.4  Consideration  of  Costs
 2.5  Consideration  of  Environmental  Impacts
 2.6  Impact  on  Existing Sources
 2.7   Revision  of  Standards of Performance
 THE FOSSIL FUEL STEAM  ELECTRIC UTILITY INDUSTRY
 3.1  General
     3.1.1   Description and Uses of Large Steam
            Generators
     3.1.2   Electric Utility Industry Statistics
     3.1.3  New Source Growth Projections
3.2  Facilities, Fuels, and Emissions
     3.2.1  Facilities and Fuels
     3.2.2  Emissions
 Page
 1-1
 1-1
 1-2
 1-2
 2-1
 2-1
 2-6
 2-8

 2-11
 2-12
 2-14
 2-15
 3-1
3-1
 3-1

 3-1
3-5
3-7
3-7
3-22

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                     TABLE OF CONTENTS
                                                       Page
NO  CONTROL TECHNOLOGY FOR PULVERIZED COAL             4-1
  /\
(EXCEPT LIGNITE) FIRED STEAM GENERATORS
4.1  Control Principles for NO                         4-1
                              X
4.2  Control Methods for Pulverized Coal-Fired         4-2
     Utility Boilers
4.3  Staged Combustion                                 4-4
4.4  Low Excess Air                                    4-5
4.5  Reduced Heat Release Rate                         4-8
4.6  Combined Techniques                               4-10
MODIFICATION AND RECONSTRUCTION                        5-1
5.1  General                                           5-1
5.2  Modification                                      5-1
     5.2.1  Scope and Effect of Modification           5-1
            Regulations
     5.2.2  Modified Pulverized Coal-Fired Steam       5-3
            Generators
     5.2.3  Modification of Oil or Gas-Fired Steam     5-6
            Generators To Fire Coal
5.3  Reconstruction                                    5-8
EMISSION CONTROL SYSTEMS                               6-1
6.1  General                                           6-1
6.2  NOX Control Techniques for Individual             6-2
     Boiler Manufacturers

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                     TABLE! OF CONTENTS
     6.2.1  Babcock and Wilcox
     6.2.2  Combustion Engineering, Incorporated
     6.2.3  Foster Wheeler Energy Corporation
            and Riley Stoker Corporation
     6.2.4  Summary of NO  Control Status
                         J\
6.3  Feasibility of Continuous NO  Control
                                 X
ENVIRONMENTAL IMPACT
7.1  General
7.2  Air Pollution Impact
     7.2.1 Effect on  Ambient Air Quality
     7.2.2 Effect on  Air Emissions
7.3  Solid Waste,  Water  Pollution,  Noise, and
     Energy Impact
ECONOMIC IMPACT ANALYSIS
8.1  Industry Profile
        i
        *
     8.1 A General  Industry  Background
     8.1.2 Coal as  the Basic  Fossil  Fuel  for
           Electric Generation
     8.1.3/' Competitors in the Coal-Fired Boiler
           Industry
8.2  Cost of Control
8.3  Cost of Other Environmental  Controls
          •--)
     8.3.1 Environmental Control Costs for  Typical
           New Installations
 Page
 6-2
 6-12
 6-24

 6-27
 6-28
 7-1
 7-1
 7-1
 7-1
 7-5
 7-6

 8-1
 8-1
 8-1
 8-6

 8-9

8-16
8-18
8-18
                          VII

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                           TABLE  OF  CONTENTS
9.
                                                        Page
      8.3.2  Total  Industry Environmental  Control        8-18
             Costs
 8.4  Economic Impact of Alternative Emission            8-20
      Control  Systems
      8.4.1  Penetration of New Units                   8-20
      8.4.2  Scenario I  Impacts                         8-22
      8.4.3  Scenario II Impacts                        8-22
      8.4.4  Scenario III Impacts                        8-24
      8.4.5  Modified/Reconstructed  Facilities           8-28
 8.5  Potential Socioeconomic  and  Inflationary  Impact    8-28
      8.5.1   Inflationary Considerations                 8-28
      8.5.2  Energy  Considerations                       8-29
      8.5.3 Secondary Socioeconomic Impacts             8-29
 8.6  Summary                                            8-29
 RATIONALE  FOR THE PROPOSED  STANDARDS                    9-1
 9.1   Selection of Source  for  Control                    9-1
 9.2   Selection of Pollutants  and Affected Facilities    9-2
 9.3   Selection of the Best  System of Emission           9-4
      Reduction Considering  Costs
 9.4  Selection of the Format  of the Proposed Standard   9-8
 9.5  Selection of Emission  Limits                       9-9
9.6  Visible Emission Standards                         9-10
9.7  Modification and Reconstruction Considerations    9-10
                                viii

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                          TABLE OF CONTENTS
     9.8  Selection of Monitoring  Requirements
     9.9  Selection of Performance Test Methods
Appendix A     Evolution of Proposed Standards
Appendix B     Index to Environmental Impact Considerations
Appendix C     Source Test Data
Appendix D     Emission Meausrement and Continuous Monitoring
Appendix E     Enforcement Aspects
Appendix F     Basis for Dispersion Estimates
Page
9-11
9-13
                               ix

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                           LIST OF TABLES
1-1  Matrix of Environmental and Economic Impacts of
     the Proposed NO  Emission Limits
                    X
3-1  Comparison of Annual Sales of Watertube Generators to
     Utilities and All Users - Capacities >31.5
     Kilograms of Steam Per Second (250,000 Ib/hr)
3-2  Fossil fuel Consumption for Power Generation 1975
3-3  1974 United States Electric Utility Power
     Generation
3-4  United States Use of Electrical Energy By
     Consuming Sector - 1974
3-5  United States Primary Energy Consumption By
     Consuming Sector and Energy Source - 1974
3-6  Characteristics of Seventeen Selected United
     States Coals
3-7  Nitrogen Content of United States Coals
3-8  Variations in Coal Ash Composition with Rank
3-9  Ash Softening Temperature and Ash Composition of
     Selected United States Coals
3-10 Summary of 1976 Nationwide Nitrogen Oxides
     Emissions by Source Category
3-11 Summary of 1976 Nationwide Nitrogen Oxides Emissions
     From Stationary Fossil Fuel Combustion Sources
3-12 Emission Factors for Coal-Fired Steam Generators
     of the Electric Utility Industry.
Page
1-4

3-2
3-3
3-3

3-4

3-6

3-13

3-12
3-14
3-15

3-23

3-24

3-25

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                           LIST OF TABLES
 4-1  NOX Control Methods for Fossil Fuel-Fired
      Utility Boilers
 6-1  Full Load NOX Emissions From A 270 Megawatt
      Babcock and Wilcox Pulverized Coal-Fired Steam
      Generator Retrofitted with Specially Designed
      Burners
 6-2  Fly Ash Carbon,  Efficiency, Oxygen, and NO
                                                J\
      at Full Load for a 270 Megawatt Modern Design
      Pulverized Coal-Fired  Steam Generator
 6-3  Carbon  Monoxide  Emissions  From A 270  Megawatt
      Babcock and Wilcox Modern  Design  Pulverized
      Coal-Fired Steam Generator at  Various Oxygen, NO  ,
                                                     X
      and  Load Levels
 6-4  Corrosion  Test Data for Two  Babcock and Wilcox
      Pulverzied Coal-Fired  Steam  Generators
 6-5  Summary of NOX Emission Control Data  for Modern
      Babcock and Wilcox Coal-Fired Steam Generators
      Equipped with Specially Designed Burners
6-6  Summary of Polycyclic Organic Matter Emissions
     From An Old Style Babcock and Wilcox 560 Megawatt
     Coal-Fired Steam Generator
6-7  Data on Tangential Pulverized Coal-Fired Steam
     Generators  Tested by the U. S.  Environmental
     Protection  Agency
 Page
 4-3

 6-6
 6-7
 6-8
 6-9
6-10
6-11
6-15
                                  xi

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                           LIST OF TABLES
6-8   Comparison of Average Boiler Efficiences



      Baseline Versus Low NO  Mode
                            X


6-9   Plant A Corrosion Test Results for Coupons



      Exposed 30 Days At 315-400°C (600-750°F)



6-10  Plant C Corrosion Test Results for Coupons



      Exposed 300 Hours At 385°C (725°F)



6-11  Plant D Corrosion Test Results For Coupons



      Exposed 30 Days At 315-400°C (600-750°F)



6-12  Plant E Corrosion Test Results for Coupons



      Exposed 30 Days at 315-400°C (600-750°F)



6-13  Summary of Maximum Full Load NO  Emission
                                     j\


      Measurements During U. S. Environmental Protection



      Agency Tests of Modern Combustion Engineering



      Tangential Coal-Fired Steam Generators



6-14  November 1977 NO  Emission Characteristics of Two
                      yx


      350MW Tangentially Fired Steam Generators



7-1   Emission Source Characteristics of the Prototype



      Pulverized Coal Combustion Plants



7-2   Maximum Pollutant Concentrations



7-3   The Effect of Various NO  Control Levels on
                              /\


      Emissions From 161,000 Megawatts of Coal-Fired



      Electric Utility Steam Generating Capacity Built



      After 1983.
Page



6-17







6-18







6-19







6-20







6-21







6-23
6-27







7-2







7-4



7-7
                                    xn

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                            LIST  OF  TABLES

                                                             Page
8-1  Coal-Fired Units  Installed  1960-1976                    8-1
8-2  Financial Data for Fossil-Fired Boiler  Industry         8-10
8-3  Reliance on Coal-Fired Boiler  Market for Each           8-10
     Supplier
8-4  Environmental Capital Cost  for New Plants               8-19
8-5  Capital Expenditures 1975-1985 by Type of Pollution     8-19
     Control Equipment
8-6  Penetration of New Coal-Fired Units Into U.S.           8-21
     Generating Base
8-7  Relative Impact of Shifting One Two-Unit (600MW)        8-27
     Order on Each Boiler Supplier
                               xi i i

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                           LIST OF FIGURES







                                                            Page



3-1   Typical Pulverized Coal-Fired Boiler                  3-8



3-2   Front Wall-Fired Boiler                               3-17



3-3   Horizontally Opposed Slag Tap Boiler                  3-18



3-4   Tangentially Fired Boiler                             3-19



3-5   Typical Pulverized Coal-Fired Boiler                  3-21



4-1   Variations in Firing Techniques for Staged            4-6



      Combustion of NO  Emissions from Existing Units
                      X


4-2   Burner Principles for Low NO  Emissions               4-7
                                  /\


4-3   Relationship Between PPM NO  and Percent Excess       4-9



      Air for Selected Coal-Fired Boilers



6-1   Dual Register Pulverized Coal Burner                  6-3



6-2   Burner Principles for Low NO  Emissions               6-4
                                  X


6-3   Schematic Overfire Air System Barry No. 2             6-13



8-1   Percentage Growth Rate Over Previous Year Reported    8-2



      By Major U.S. Utility Systems



8-2   Annual Peak Reserves as a Percentage of Total         8-4



      Available Capacity 1961-1977



8-3   Annual Capacity Factor for the Major U.S.             8-5



      Electric Utilities



8-4   Aggregate Annual Number of Installed Coal-Fired       8-7



      Units Over 25MW on a 5-Year Running Average



8-5   Average Size of Newly Installed Coal-Fired Units      8-8



      on a 5-Year Running Average
                                xiv

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                           LIST OF FIGURES
8-6   Annual Installed Megawatt Capacity as a Percentage
      of the Total Coal-Fired Market on a 5-Year Running
      Average
8-7   Annual Installed Megawatt Capacity for Coal-Fired
      Units on a 5-Year Running Average
8-8   Size Distribution of Coal-Fired Power Plants
      Installed 1960-1978 for 4 Suppliers
Page
8-11
8-12
8-14
                                xv

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                               1.  SUMMARY


1.1  PROPOSED STANDARDS

     This Background Information document supports proposed nitrogen

oxides (NOX) emission limits for the combustion of pulverized coal

(except lignite and coal refuse) in new electric utility steam generating

units with heat input rates greater than 73 MW (250 million Btu per hr).

The proposed NOV emission limits for units which burn lignite, coal
               A

refuse, shale.oil, fuels derived from coal, and other liquid and gaseous

fuels are based in other studies, as noted in Chapter 9, and are not

discussed in this document.  Additional  information may be found in the

preamble and regulation for Subpart Da in the Federal Register.

     The proposed emission limits under 40 CFR Part 60, Subpart Da would

restrict NO  emissions to:
           /\

          86 ng/J heat input (0.20 Ib/million Btu) from the
     combustion of any gaseous fuel. except gaseous fuel
     derived from coal;

          130 ng/J heat input (0.30 1 fa/million Btu) from the
     combustion of any liquid fuel, except shale oil  or liquid
     fuel  derived from coal;

          210 ng/J heat input (0.50 Ib/million Btu) from the
     combustion of subbituminous coal, shale oil, or any fuel
     derived from coal.
                                   1-1

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          340 ng/0 heat input (0.80 Ib/million Btu) from the
     combustion in a slag tap furnace of any fuel  containing
     more than 25 percent, by weight, lignite which has been
     mined in North Dakota, South Dakota, or Montana;
          260 ng/J heat input (0.60 In/million But) from the
     combustion of any solid fuel not covered above, except that
     the combustion of any fuel  containing more than 25 percent,
     by weight, coal refuse is exempt from the standards.
These emission limits would be monitored continuously, based on a
daily averaging period of 24 hours.
     Control of NO  emissions from pulverized coal-fired electric utility
                  X
steam generating units is achieved by modifying the way the coal is combusted
in the furnace.  The best combustion modification system is a combination
of staged combustion, low excess air, and reduced heat release rate.

1.2  ENVIRONMENTAL IMPACT
     The proposed limits would reduce NO  emissions by 14 to 29 percent
                                        X
from most pulverized coal-fired units without adversely affecting water
quality, solid waste disposal, or energy conservation.  Furthermore, the
proposed NO  emission limits would not cause signficant increases in other
           /\
air pollutants, including sulfur dioxide, particulate matter, carbon
monoxide, and hydrocarbons.

1.3  ECONOMIC IMPACT
     An economic impact assessment of the proposed  regulations has been
prepared, as required under section  317 of the Clean Air Act (as amended
in 1977).  The proposed regulations  would have small or negligible impacts
on:  the costs of compliance; inflation or recession; competition with
respect to small business; consumer  costs; and energy use.  A complete
economic impact analysis appears in  Chapter 8.
                                   1-2

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     The environmental  and economic impacts of the proposed emission
limits are summarized in Table 1-1.
                               1-3

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                           2.  INTRODUCTION

      Standards of performance are proposed following a detailed investigation
 of air pollution control methods available to the affected industry and the
 impact of their costs on the industry.   This document summarizes the informa-
 tion obtained from such a study.  Its purpose is to explain in detail the
 background and basis of the proposed standards and to facilitate analysis of
 the proposed standards by interested persons,  including those who may not be
 familiar with the many technical aspects of the industry.   To obtain additional
 copies of this document or the Federal Register notice of proposed  standards,
 write to EPA Library (MD-.35),  Research Triangle Park,  North Carolina 27711.
 Specify Electric  Utility Steam Generating Units -  Background Information  for
 Proposed N0x Emission Standards,  report  number EPA-450/2-78-005a, when ordering.
 2.1   AUTHORITY FOR THE STANDARDS
      Standards  of performance  for new stationary sources are established
under section 111 of the Clean Air Act (42 U.S.C.  7411), as amended, hereafter
referred to  as  the Act.  Section 111 directs the Administrator to establish
standards of performance for any category of new stationary sources of air
pollution which "... causes or  contributes significantly to, air pollution
which may reasonably be anticipated to endanger public health or welfare."
                                 2-1

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     The Act requires that standards of performance for stationary
sources reflect, ". . . the degree of emission limitation achievable
through the application of the best technological system of continuous
emission reduction ... the Administrator determines has been
adequately demonstrated."  In addition, for stationary sources whose
emissions result from fossil fuel combustion, the standard must also
include a percentage reduction in emissions.  The Act also provides
that the cost of achieving the necessary emission reduction, the
nonair quality health and environmental impacts and the energy
requirements all be taken into account in establishing standards of
performance.  The standards apply only to stationary sources,  the
construction or modification of which commences after regulations are
proposed by publication in the Federal  Register.
     The 1977 amendments to the Act altered or added numerous  provisions
which apply to the process of establishing standards of performance.
     1.  EPA is required to list the categories of major stationary
sources which have not already been listed and regulated under
standards of performance.   Regulations  must be promulgated for these
new categories on the following schedule:
     25 percent of the listed categories by August 7,  1980
     75 percent of the listed categories by August 7,  1981
     100 percent of the listed categories by August 7, 1982
A governor of a State may apply to the  Administrator to add a  category
which is not on the list or to revise a standard  of performance.
     2.  EPA is required to review the  standards  of performance every
four years, and if appropriate, revise  them.
                                2-2

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      3.  EPA is authorized to promulgate a design, equipment, work
 practice, or operational standard when an emission standard is not
 feasible.
      4.  The term "standards of performance" is redefined and a new
 term "technological system of continuous emission reduction" is defined.
 The new definitions clarify that the control system must be continous
 and may include a low-polluting or non-polluting process or operation.
      5.  Hie time between the proposal and promulgation of a standard
 under section 111 of the Act is extended to six months.
      Standards of performance,  by themselves, do not guarantee protection
 of health or welfare because they are not designed to achieve any specific
 air quality levels.   Rather,  they are designed to reflect the degree of
 emission limitation achievable  through application of the best
 adequately demonstrated technological system of continuous emission
 reduction,  taking into consideration the  cost of achieving such emission
 reduction, any nonair quality health and  environmental impact  and energy
 requirements.
                                                            /
     Congress had several reasons for  including these  requirements.
 First,  standards xd.th  a degree of uniformity are needed to avoid
 situations where some  States may attract industries by relaxing standards
 relative to other States.  Second, stringent standards enhance the
 potential for long term growth.  Third, stringent standards may help
 achieve long-term cost  savings by avoiding the need for more expensive
 retrofitting when pollution ceilings may be reduced in the future.
Fourth, certain types of standards for coal burning sources can
adversely affect the coal market by driving up the price of low-sulfur
                                2-3

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coal or effectively excluding certain coals from the reserve base
because their untreated pollution potentials are high.  Congress does
not intend that new source performance standards contribute to these
problems.  Fifth, the standard-setting process should create incentives
for improved technology.
     Promulgation of standards of performance does not prevent State or
local agencies from adopting more stringent emission limitations for the
same sources.  States are free under section 116 of the Act to establish
even more stringent emission limits than those established .under section
111 or those necessary to attain or maintain the national ambient air
quality standards (NAAQS) under section 110.  Thus, new sources may in
some cases be subject to limitations more stringent than standards of
performance under section 111, and prospective owners and operators of
new sources should be aware of this possibility in planning for such
facilities.
     A similar situation may arise when a major emitting facility is to
be constructed in a geographic area which falls under the prevention of
significant deterioration of air quality provisions of Part C of the
Act.  These provisions require, among other things, that major emitting
facilities to be constructed in such areas are to be subject to best
available control tectinology.  The term "best available control tech-
nology" (BACT), as defined in the Act, means ". .  .an emission
limitation based on the maximum degree of reduction of each pollutant
subject to regulation under this Act emitted from or which results from
any major emitting facility, which the permitting authority, on a
case-by-case basis, taking into account energy, environmental, and
economic impacts and other costs, determines is achievable for such

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 facility through application of production processes and available
 methods, systems, and techniques, including fuel cleaning or treatment
 or innovative fuel combustion techniques for control of each such
 pollutant.   In no event shall application of 'best available control
 technology' result in emissions of any pollutants which will exceed the
 emissions allowed by any applicable standard established pursuant to
 section 111 or 112 of this Act."
      Although standards  of performance are normally structured  in terms
 of numerical emission limits where feasible, alternative approaches  are
 sometimes necessary.   In some cases  physical measurement of  emissions
 from  a new  source may be impractical or exorbitantly expensive.   Section
 lll(h) provides that  the Administrator may promulgate a  design of
 equipment standard in those cases where it is not feasible to prescribe
 or enforce a standard of performance.  For example, emissions'of
 hydrocarbons from storage vessels  for  petroleum liquids  are  greatest
 during  tank filling.  The nature of  the emissions,  high  concentrations
 for short periods  during filling,  and  low concentrations for longer
 periods .during storage,  and the configuration of storage tanks make
 direct emission measurement impractical.  Therefore, a more  practical
 approach to  standards of performance for  storage vessels has been
 equipment specification.
      In addition, section  lll(h) authorizes the Administrator to grant
waivers of compliance to permit a source  to use  innovative continuous
 emission control technology.  In order to grant  the waiver, the
Administrator must find:    (1) a substantial likelihood that the technology
mil produce greater emission reductions than the standards require,  or
an equivalent reduction at lower economic, energy or environmental cost;
                                2-5

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 (2) the proposed system has not becm. adequately demonstrated; (3) the



 technology will not cause or contribute to an unreasonable risk to public



health, welfare or safety;  (4) the governor of the State.where the source



 is located consents; and that, (5) the waiver will not prevent the



 attainment or maintenance of any ambient standard.  A waiver may have



 conditions attached to assure the source will not prevent attainment of



 any NAAQS.  Any such condition will have the force of a performance



 standard.  Finally, waivers have definite end dates and may be terminated



 earlier if the conditions are not met or if the system fails to perform



•as expected.  In such a case, the source may be given up to three years



 to meet the standards, with a mandatory progress schedule.





 2.2   SELECTION OF CATEGORIES OF' STATIONARY SOURCES



      Section 111 of the Act directs the Administrator to list categories



 of stationary sources which have not been listed before.  The



 Administrator,  ".  .  .  shall include a category of  sources in such  list



 if in his judgment  it  causes, or  contributes  significantly  to, air



 pollution which may reasonably be anticipated to endanger public health



 or welfare."  Proposal and promulgation of standards of  performance are



 to follow xvhile adhering to the schedule referred  to earlier.



      Since passage of the Clean Air Amendments of 1970, considerable



 attention has been given to the development of a system for assigning



 priorities to various source categories.  The approach specifies areas



 of interest by considering the broad strategy of the Agency for



 implementing the Clean Air Act.  Often, these "areas" are actually



 pollutants which are emitted by stationary sources.  Source categories



 which emit these pollutants were then evaluated and ranked by a process



 involving such factors as  (1) the level of emission control (if any)



                                2-6

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  already required by State regulations;  (2)  estimated levels of control
  that might be required from standards of performance for the source
  category;  (3) projections of growth and  replacement  of existing
  facilities for the  source category;  and  (4)  the  estimated incremental
  amount  of  air pollution that could  be prevented, in  a  preselected  future
  year, by standards  of performance for the source category.  Sources for
  which new  source performance standards were promulgated or are under
  development during  1977 or earlier, were selected on these criteria.
      The Act  amendments of August, 1977, establish specific criteria
  to be used in determining priorities for all source categories not yet
  listed by EPA.  These are
      1)  the quantity of air pollutant emissions which each such
 category will emit,  or will be designed to emit;
      2)  the extent  to which each such pollutant may reasonably be
 anticipated to endanger.public health or  welfare; and
      3)   the mobility and competitive nature of each  such category  of
 sources  and the consequent need for  nationally applicable new source
 standards of performance.
      In  some cases,  it may not be feasible to  inrosdiately develop a
 standard for a source category with  a high priority.  This might happen
]when  a program of research is needed  to develop control techniques or
because  techniques for sampling and measuring emissions may require
refinement.  In the  developing  of standards, differences in the time
required to complete the necessary investigation for different source
categories must- also be considered.  For example, substantially more
time may be necessary if numerous pollutants must be investigated from
a single source category.  Further,  even late in the development
                                 2-7

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process the schedule for completion of a standard may change.  For
example, inability to obtain emission data from well-controlled sources
in time to pursue the development process in a systematic fashion may
force'a change in scheduling.  Nevertheless, priority ranking is, and
will continue to be, used to establish the order in which projects are
initiated and resources assigned.
     After the source category has been chosen, determining the types of
facilities within the source category to which the standard will apply
mast be decided.  A source category may have several facilities that cause
air pollution and emissions from some of these facilities may be
insignificant or very expensive to control.  Economic studies of the
source category and of applicable control technology may show that air
pollution control is better served by applying standards to the more
severe pollution sources.  For this reason, and because there be no
adequately demonstrated system for controlling emissions from certain
facilities, standards often do not apply to all facilities at a source.
For the same reasons, the standards may not apply to all air pollutants
emitted.  Thus, although a source category may be selected to be covered
by a standard of performance, not all pollutants or facilities within
that source category may be covered by the standards.

2.3  PROCEDURE FOR DEVELOPMENT OF STANDARDS OF PERFORMANCE
     Standards of performance must (1) realistically reflect
best demonstrated control practice; (2) adequately consider the cost,
and the nonair quality health and environmental impacts and energy require-
ments of such control; (3) be applicable to existing sources that are
modified or reconstructed as well as new installations; and (4) meet these
                                2-8

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 conditions for all variations of operating conditions being considered
 anywhere in the country.
      The objective of a program for development of standards is to identify
 the best technological system of continuous emission reduction which has
 been adequately demonstrated.  The legislative history of section 111 and
 various court decisions make clear that the Administrator's judgment of
 what is adequately demonstrated is not limited to systems that are in
 actual routine use.   The search may include a technical .assessment of
 control systems which have been adequately demonstrated but for which
 there is limited  operational experience.   In most cases,  determination of
 the ".  .  . degree of  emission reduction achievable .  .  ."is based on
 results of tests  of emissions from well controlled existing sources/At
 times,  this has required the investigation and measurement  of emissions
 from control systems  found  in other industrialized countries
 that  have developed more  effective systems of control than  those
 available in the United States.
      Since the best demonstrated systems of emission reduction may not
be  in widespread use, the data base upon which standards are developed
may be somewhat limited.  Test data on existing well-controlled sources
are obvious starting points in developing emission limits  for new
sources.  However, since the control of existing sources generally
 represents retrofit technology or was originally designed to meet an
 existing State or local regulation, new sources may be able to meet
more  stringent emission standards.  Accordingly, other information must
be considered before a judgment can be made as to the level at which
the emission standard should be set.
                                2-9

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      A process  for the development  of a standard has  evolved which  takes



  into account the following considerations.



      1.   Emissions from existing well-controlled sources  as measured.



      2.   Data on emissions from such sources  are assessed with considera-



  tion of such factors  as:  (a) how representative the tested source is in



  regard to feedstock,  operation,  size,  age,  etc.; (b)  age  and maintenance



  of the control  equipment tested;  (c)  design uncertainties of control



  equipment being considered; and  (d)  the'degree of uncertainty that  new



  sources  XinLll be able,  to achieve  similar levels of control.



      3.   Information  from pilot  and prototype installations, guarantees



  by vendors of control equipment, unconstructed but contracted projects,



  foreign technology, and published literature  are also considered during



.  the standard development process.   This is  especially important for



  sources  where "emerging" technology appears to be a significant alternative.



      4.   Where  possible,  standards  are developed which permit the use  of



  more than one cohtrol technique  or  licensed process,.



      5.   Where  possible,  standards  are developed to encourage or permit



  die use of process modifications or new processes as  a method of control



  rather than  "add-on"  systems of  air pollution control.



      6.   In  appropriate cases, standards are  developed to permit the use



  of systems capable of controlling more than one pollutant.  As an example,



  a  scrubber can  remove both gaseous  and particulate emissions, but an



  electrostatic precipitator is specific to particulate matter.




        7.  Where appropriate, standards  for visible emissions are developed



  ill conjunction xd.th  concentration/mass  emission standards.  The opacity



  standard is  established at a level  that will require proper operation and



  maintenance  of the emission control system installed to meet the




                                 2-10

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 concentration/mass standard on a day-to-day basis,  m SOme cases, hcvever,
 it is not possible to develop concentration/mss standards, such as with
 fugitive sources of emissions.  In these cases, only opacity standards nay
 be developed to limit emissions.

 2.4  CONSIDERATION OF COSTS
      Section 317 of the Act requires, among other things, an economic
 impact assessment with respect to any standard of performance established
 under section 111 of the Act.   The assessment  is required to contain an
 analysis of:
      (1)  the costs of compliance with the regulation and standard
 including the extent to which  the cost of compliance varies depending
 on the effective date of  the -standard  or regulation and the development
 of less expensive or more efficient methods of compliance;
      (2)  the potential, inflationary recessionary effects of the
 standard or regulation;
      (3)  the effects on competition of the standard or regulation with
respect to small business;
      (4)  the effects of the standard or regulation on consumer cost, and,
      (5)  the effects of the standard or regulation on energy use.
      Section.317 requires that the economic impact assessment be as
 extensive as practible, taking into account the time and resources
 available to EPA.
      The economic  impact  of a  proposed standard upon an industry is usually
 addressed both  in  absolute  terms and by comparison with the control costs
 that  would be incurred as a result of  compliance x^th typical existing State
 control  regulations.  An  incremental approach is taken since both new and
                               2-11

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 existing plants would be required to comply with State regulations in
 the absence of a Federal standard of performance.  Ibis approach
 requires a detailed analysis of the impact  upon  the industry resulting
 from the cost differential that exists between a standard of performance
 and the typical State standard.
      The costs  for  control  of  air pollutants are not the only costs considered.
 Total environmental  costs  for  control of water  pollutants as well as air
 pollutants are analyzed wherever possible.
      A thorough study of the profitability and  price-setting mechanisms of  the
 industry is essential to the analysis so that an accurate estimate of
 potential adverse economic impacts can be made.  It is also essential to know
 the capital  requirements placed on plants  in the absence of Federal standards
 of performance so that the additional capital requirements necessitated by
 these standards can be placed in the proper perspective.   Finally, it is
 necessary to  recognize any constraints  on capital availability within an
 industry, as  this factor also influences the ability of new plants to generate
 the capital required for installation of additional control equipment
 needed to meet  the standards of performance

 2.5   CONSIDERATION OF ENVIRONMENTAL IMPACTS
      Section  102(2)(C) of the National Environmental Policy Act (NEPA) of
 1969  requires Federal agencies to prepare detailed environmental  inpact
 statements on proposals for legislation and other major Federal actions
 significantly affecting the quality of the human environment.  The objective
of NEPA is to build into the decision-making process of Federal agencies a
careful consideration of all environmental aspects of proposed actions.
                                2-12

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     In a number of legal challenges to standards  of performance for


various industries, the Federal Courts of Appeals  have'held that


environmental impact statements need not be  prepared by the Agency for


proposed actions under section 111 of the Clean Air Act.  Essentially, the


Federal Courts  of  Appeals  have determined that "... the best system of   '


emission reduction,  .  .  .  require(s)  the Administrator to take into  account


counter-productive environmental  effects of a proposed standard, as  well


as economic costs  to  the industry .  .  ." On this basis, therefore,  the


Courts ". . . established  a  narrow exemption from NEPA for EPA determination
                            (

under section 111."



     In addition to these  judicial  determinations, the Energy Supply and '


Environmental Coordination Act (ESECA)  of 1974 (PL-93-319) specifically


exempted proposed  actions  under the Clean Air Act from NEPA requirements.


According to section 7(c)(l),  "No  action taken under the Clean Air Act


shall be deemed a  major .Federal action  significantly affecting the quality


of the human environment within the meaning of the National  Environmental


Policy Act of 1969."


     The. Agency has'concluded, however,  that the preparation of environmental


impact statements  could have beneficial  effects on certain regulatory actions.


Consequently,  while not legally required to do so by section 102(2)(C) of


NEPA, environmental impact statements will  be prepared for various regulatory


actions, including standards of performance developed under section 111  of


the Act.  This voluntary preparation of  environmental impact  statements,


however, in no way legally  subjects the Agency to NEPA requirements.


     To implement  this  policy, a  separate section is included in this


document which  is  devoted  solely  to an  analysis of the potential environmental



                               2-13

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 impacts  associated with  the proposed standards.  Both adverse and bene-
 ficial impacts  in such areas as air and water pollution, increased solid
Xtfaste disposal, and increased energy consumption are identified and
discussed.

2.6  IMPACT ON EXISTING  SOURCES
     Section 111 of the Act defines a new source as ". . . any stationary
source,  the construction or modification of which is commenced ..."
after the proposed standards are published.  An existing source becomes
a new source if the source is modified or is reconstructed.  Both
modification and reconstruction are defined in amendments to the general
provisions of Subpart A of 40 CFR Part 60 which were promulgated in the
Federal Register on December 16, 1975 (40 FR 58416).  Any physical or
operational change to an existing facility which results in an increase
in the emission rate of any pollutant for which a standard applies is
considered a modification.  Reconstruction, on the other hand, means the
replacement of components of an existing facility to the extent that the
fixed capital cost exceeds 50 percent of the cost of constructing a
comparable entirely new source and that it be technically and economically
feasible to meet the applicable standards.  In such cases, reconstruction
is equivalent to new construction.
     Promulgation of a standard of performance requires States to establish
standards of performance for existing sources in the same industry under
section lll(d) of the Act if the standard for new sources limits emissions
of a designated pollutant (i.e. a pollutant for which air quality criteria
have not been issued under section 108 or which has not been listed as a
hazardous pollutant under section 112).   If a State does not act, EPA must
                                2-14

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establish such standards.   General provisions outlining'procedures for
control of existing sources under section lll(d) were promulgated on
November 17,  1975,  as Subpart B of 40 CFR Part 60 (40 FR 53340).

2.7  REVISION-OF STANDARDS OF PERFORMANCE
     Congress was  aware that the.level  of air pollution control  achievable
by any industry may  improve with technological advances.  Accordingly,    '
section 111 of the Act provides that the Administrator ". .  .  shall, at
least every four years, review and, if  appropriate, revise  . .  ." the
standards.  Revisions are  made to assure that the standards continue to
reflect the best systems that become available in the future.  Such
revisions will not be retroactive but will apply to stationary sources
constructed or modified after the proposal of the revised'standards.
                              2-15

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       3.   THE FOSSIL FUEL STEAM ELECTRIC UTILITY INDUSTRY
,3.1   GENERAL
 3.1.1  Description and Uses  of Large Steam Generators
      A large fossil  fuel-fired steam generator is  a  unit of more  than  73
 megawatts (250 X 106 BTU/Hr)  heat input.   A 73 megawatt (250 X  106
 BTU/Hr) steam generator produces  enough  steam to generate approximately=25
 megawatts of electric power.1'2  The largest fossil  fuel-fired  steam
 generators in the United States produce  enough steam to generate  1300.
           3
 megawatts.   As  shown by Table 3-1,  nearly all  large fossil  fuel-fired;-;
 steam generators are sold to  the  electric  utility  industry for  generation
 of electric power.    A few large  steam generators  are  sold to produce
 steam for industrial  use.
 3.1.2  Electric  Utility Industry  Statistics
      At the end  of 1975,  the  total capacity  of fossil  fuel-fired  steam
 generator power  units  was  347.7 gigawatts.3   Table 3-2  shows statistics on
 1975  fuel  consumption/  As shown, 60 percent of the thermal energy was
 supplied  by coal  and the  remainder was about equally split between gas and
 oil.
                                3-1

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                           TABLE  3-1
      COMPARISON OF ANNUAL SALES  OF WATERTUBE GENERATORS4
                 TO UTILITIES  AND TO  ALL  USERS
CAPACITIES >31.5 KILOGRAMS OF  STEAM PER SECOND  (250,000 Ib/hr)
Year
              Total  Steam  CapacitygSold
          Megaqrams  per Second  (10  Ib/hr)
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
To All Users
13.02 (103.3)
10.05 (79.8)
14.92 (118.4)
T8.85 (149.6)
24.03 (190.7)
22.43 (178.0)
26.11 (207.2)
25.14 (199.5)
27.00 (214.3)
31.08 (246.7)
18.60 (147.6)
21.31 (169.1)
33.30 (264.3)
37.16 (294.9)
13.37 (106.1)
7.17 (56.9)
To Utilities
12.40 (98.4)
9.69 (76.9)
13.94 (110.6)
16.93 (134.4)
21.37 (169.6)
20.69 (164.2)
24.99 (198.3)
23.89 (189.6)
24.99 (198.3)
29.74 (236.0)
17.83 (141.5)
19.35 (153.6)
30.47 (241.8)
34.41 (273.1)
11.37 (90.2)
6.27 (49.8)
TOTAL
343.54 (2726.4)
318.33 (2526.3)
                               3-2

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                               TABLE 3-2

        ,  FOSSIL FUEL CONSUMPTION FOR POWER GENERATION 19753
 Fossil  Fuel
 Coal
 Oil
 Gas
Consumption
366.1 x 10 f.Kilograms
(403.6 x 10° tons)
Percent of Total Heat Input
72.50 x 10D,-Cubic Metres
(456.0 x 10b Bbl)


8.38 x 101?,Cubic Metres
(2.96 x 10'^ Ft3)
                                                          60.0
                                                          19.2
                                                          20.8
                               TABLE  3-3

        1974  UNITED  STATES  ELECTRIC UTILITY  POWER  GENERATION5
Type
Fuel Burning



Nuclear



Hydropower



TOTAL



(a)
            (a)
     Power Generation
        Exajoules
       (IP9 Kw Hr)
         5.28 .
        (1466)
          .40
         (110)
        1.05
        (291)
        6.73
        (1867)
       Percent
        78.5
         5.9
        15.6
       100.0
     Includes oil and gas turbines
                               3-3

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     Table 3-3 shows 1974 United States total electric utility energy
generation.   Additional electrical energy is generated by industry,
remote domestic units, and by automobiles, aircraft, construction
equipment, locomotives, and vessels.  As shown in Table 3-3, about 79
percent of the 1974 electric utility energy was generated from fossil
fuels.  About 16 percent was generated by hydropower systems and about
6 percent was generated by nuclear power plants.
     Table 3-4 shows use of 1974 electric utility generated energy by
consuming sector.   As shown, about 58 percent of the total electrical
energy was used for domestic or commercial purposes.  About 42 percent
was used by the industrial sector.  Transportation uses very little of
the electrical energy generated by power plants because it is more
practical to equip mobile units with internal generating systems.
                              TABLE 3-4
  UNITED STATES USE OF ELECTRICAL ENERGY BY CONSUMING SECTOR  19745
Sector
Household and Commercial
Industrial
Transportation^9'
     TOTAL
(a)
                                  Exajoules Used
                                    (IP15 Btu)
                                      3.89
                                     (3.69)
                                      2.81
                                     (2.67)
                                      0.02
                                     (.016)
                                      6.72
                                     (6.37)
Percent
 57.9
 41.8
  0.3
100.0
     Does not include electrical energy generated by transportation
     equipment, such as automobile generators, etc.
                               3-4

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     Table 3-5 shows total United States energy  consumption  by  consuming
sector and energy source.5  As shown,  United  States energy is derived
primarily from fossil fuels with small percentages derived from nuclear,
hydropower, and geothermal energy sources.  About 46 percent is furnished
by petroleum, 30 percent by natural gas, and  18  percent by coal.  About
27 percent of United States energy is  used for electric power generation.
About the same proportion is used by the industrial and transportation
sectors.  Household and commercial sectors use about 19 percent of the
total energy.  Most of the coal is used for electric power generation
with other large use by the industrial sector.   The transporation
sector uses more than one-half of petroleum derived energy.  Household
and commercial, industrial, and electrical generation sectors use other
large quanitites of petroleum derived energy.  As shown by Table 3-5,
about one-half of the energy used by industry other than electrical
energy comes from natural gas.  Household, and commercial and electrical
generation sectors also use large volumes of natural  gas.   Little
natural gas is used by the transportation sector.
3.1.3  New Source Growth Projections
     For new source growth projections, see "Review of New Source
Standards for S02 Emissions from Coal-Fired Utility Boilers,  Volume 1,
Non Air-Quality Impact Assessment," Teknekron, Inc.,  Emission Standards
and Engineering Division, Office of Air Quality Planning and  Standards,
U. S. Environmental  Protection Agency, Research Triangle Park,  North
Carolina, 1978.
                             3-5

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 3.2  FACILITIES, FUELS, AMD EMISSIONS
 3.2.1  Facilities and Fuels
      Large fossil fuel-fired steam generators are classified in several
 different ways as follows:
      Fuel
      Firing Method
      Physical  state of ash                                         .
      Fluid flow                                        '        .  .'  .
      Draft
      Manufacture
 3.2.1.1   Common Characteristics
      Figure 3-1  shows  a typical  large fossil  fuel-fired steam generator
 system.   Although there is a wide difference  among  steam generators,
 they  have common characteristics.   A  common design  objective is to
 produce the required quantity and quality  of  steam  at  minimum cost.
 Air preheated  to as much as 315°C C6.QO°F);  by  the  combustion  gases is
 introduced  into  the combustion chamber with the fuel through multiple
 burners strategically  arranged to promote  optimum combustion conditions.
 In the combustion chamber, the combustible matter reacts with  the
 oxygen of the  air to release thermal  energy at temperatures  exceeding
 11QQ°C (2000°F).,   The walls of the combustion chamber  are lined with
water-filled tubes which absorb thermal energy and generate  steam. The
water tubes are  filled with liquid or vapor, depending  on pressure and
temperature conditions.
     Heat transfer in the combustion chamber cools the  combustion gases
to about 1100°C  (2000*F)..6  The cooler combustion gases flow from the
                            3-7

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        Figure 3-1



Typical pulverized coal fired boiler




          3-8

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combustion chamber to the superheat and reheat sections of the steam
generator where further heat transfer and gas cooling occur.  Steam
superheat and reheat are necessary for thermodynamic efficiency and
also to prevent steam condensation which would damage the blades of the
steam turbines which turn the electric power generators.  Modern steam
electric power generation systems use steam at pressures ranging from
13.8 to 27.6 megapascals (2000-4000 PSI) at a minimum temperature of
about 540°C (1000°F).6  Steam turbines are designed in stages so that
steam is sent back to the steam generator for reheat between stages.
Most modern systems are designed with a superheat stage followed by a
reheat stage.   Some systems are designed with more than one reheat
stage. The most efficient fossil fuel-fired steam-electric system
generates 3.6 mega.joules Cone kilowatt hour) of electrical energy from
9.2 megajoules (8714 Btu) of gross thermal energy input.7  Most modern
systems generate 3.6 mega.joules (one kilowatt hour) of electric energy
from less than 10.60 megajoules (10,000 Btu) heat input.7  Because of
the thermal energy losses of the steam turbine thermodynamic cycle and
the heat losses from the steam generator, less than 40 percent of the
thermal  energy of the fuel  is converted to electrical  energy.  About 12
to 20 percent of the gross  heat input is lost in the steam generation
system and the remainder is lost in the steam turbine system, mostly as
latent heat in the turbine  condenser.            *
     Combustion gases from  the superheat and reheat sections flow to
the economizer section where heat is transferred to the steam generator
feedwater.   Combustion gas  temperature out of the economizer ranges
from 315°C to  480°C (600-900°F).6  Combustion gases from the economizer
                         3-9

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flow to the air preheater.  When hot-side electrostatic precipitators
are used for fly ash collection, the dust collection system is located
between the economizer and air preheater.  With cold-side electrostatic
orecipitators, the dust collection system and flue gas desulfurization
system, if any, are located after the air preheater and before the
induced draft fan and stack.  The air preheater heats the air flowing
to the steam generator combustion chamber.  Combustion gas temperature
out of the air preheater ranges from 120°C to 200°C (250-400°F).6
     To minimize heat loss, large steam generator air preheaters are
designed to reduce stack temperature to the lowest level which does not
cause corrosion problems.  Corrosion will occur in and after the air
preheater if the combustion gas temperature falls below the dew point
of sulfuric acid mist.  Consequently, air preheaters are designed for
higher outlet temperatures when high sulfur fuels are fired than when
low sulfur fuels are burned.  Heat losses from the steam generation
system are also minimized by insulating hot surfaces and by minimizing
the quantity of combustion air.  The extent of combustion air reduction
is limited by the needs for nearly complete oxidation of the fuel,
steam superheat, minimal  slagging and tube wastage (corrosion), and
                ft Q in n
flame stability.°'3'IUs "  These factors are related to MO  control and
                                                          X
are discussed in greater depth in Chapters 4 and 6.
3.2.1.2  Fuels
     Large fossil fuel-fired steam generators are designed to fire
either coal, oil, or gas  or a combination of these fuels.   Since no new
large oil  or gas-fired steam generators are planned for the future, no
data are reported for oil or gas fuels.  Discussion of coal is largely
                            3-10

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 limited  to  coal  other  than  lignite because regulations for limiting NO
                                                                      X
 emissions from  large lignite-fired steam generators are being developed
            12
 separately.
     To  distinguish between  lignite, subbituminous, and other coals,
 ASTM Specification D388 defines lignite as a coal with a moist, mineral
 matter free, calorific value less than 19.3 megajoules per kilogram
 (8300 Btu/lb)   and subbituminous coal as a coal with a moist, mineral
 matter free calorific value  ranging from 19.3 to 26.8 megajoules per
 kilogram (8300-11,500 Btu/lb}.  The moist, mineral matter free calorific
 value of coal is calculated  as follows:6'13
     Moist, Mineral-Matter Free Calorific Value (megajoules per kilogram)=
          HVM-  .11635
     100 -  (1.08A + .555)    *  IUU
 expressed in the English units of ASTM D388 is:
     Moist, Mineral-Matter Free Calorific Value (Btu per pound) =
          HVE - 60S
     100 - (1.08A + .555)
                           X   100
where:
     HVM  = metric unit heating value of moist coal in megajoules
            per kilogram
     HVE  = English unit heating value of moist coal in Btu per pound
       S  = percent sulfur by weight
       A  = percent ash by weight
     The prime fuel characteristics affecting NOV control  are moisture,
                                                X
nitrogen, heating value, sulfur, ash composition, and ash  consistency.8'9'10'11
Moisture, nitrogen, and heating value affect MOV formation.   Sulfur,
                                               X
ash composition, and ash consistency may limit the way a steam generator
can bejiesigned to limit N0v emissions.8'9'10'11  The effect of the
                           X
                            3-11

-------
 foregoing characteristics on N0x control  is disucssed in Chapters  4  and
 6.
      Table 3-6 shows selected properties  of a variety of United  States
 coals.    As shown,  the Western coals  usually have  low sulfur content,
 high moisture content, and low heating  value.   Eastern coals contain
 less moisture and  have a  higher heating value.   The  sulfur  content of
 Eastern  coal  ranges  from  less than  1  percent to  more than 4 percent.
      Table 3-7 shows the  ranges in  nitrogen content  for various  ranks
 of  United States coal.   5'4  Table  3-8  shows the range of coal ash
 composition for various ranks of United States coals.15 As  shown, the
 percentages of the various ash constituents  varies widely.   Table  3-9
 shows ash softening  temperatures  for  several  United  States  coals.6   As
 shown, the difference  between the ash softening  temperature  in a reducing
 and  oxidizing  atmosphere  is  greater when  Fe203 is a  large fraction of
 the  ash.   Chapters 4 and  6 discuss how  coal  nitrogen  content, ash
 composition, and ash consistency affect NO   control.
                                          J\
                               TABLE 3-7
                NITROGEN CONTENT OF UNITED STATES COALS
                                          Nitrogen Content
                                          Percent by Weight,
                                          Moisture, Ash-free
                                               Basis
Lignite12
Subbituminous
High Volatile C Bituminous
High Volatile B Bituminous
High Volatile A Bituminous
14
.14
14
1.0 - 1.4
1.2 - 1.7
1.6 - 2.1
1.7
1.6 - 1.9
                                3-12

-------
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-------
3.2.1.3  Firing Methods for Large Pulverized Coal-Fired Generators
     The three basic types of pulverized coal-fired steam generators
are single wall, horizontally-opposed, and tangential-fired designs.
                                           ./  •
As discussed later, single wall, horizontally-opposed, or tangential-
fired units can be designed for either dry ash or slag tap (molten
ash) operation.  Figure 3-2 depicts a single wall-fired design.  As
shown, the burners are located in horizontal rows in one wall of the
furnace. Figure 3-3 shows a horizontally-opposed, slag tap design.
The burners are located in horizontal rows in opposite furnace walls.
Figure 3-4 shows a tangential, dry ash design.  The burners are located
vertically at  each of the four corners of the furnace and are directed
to create a swirling ball of hot combustion gases.
     Slag tap designs cannot be used for all types of coal.  The ash
fusibility temperature characteristics of a coal determine if a slag
tap design can be used.  Although no maximum ash fusibility temperature
can be quoted, slag tap units cannot be designed to fire coal which
produces ash of high fusibility temperature.  Dry ash units can be
designed to fire coal of either high or low ash fusibility temperature.
When coal ash fusibility temperature is low, larger combustion chambers
are provided for dry tap designs.  Enlarging the combustion chamber
and locating the burners away from the bottom reduces bottom temperatures
and produces a dry ash.  Dry ash units specially designed to fire coal
of low ash fusibility temperature are the most adaptable for firing a
variety of coals.  However, expert advice is needed to determine if
any given steam generator is adaptable to different kinds of coal.
                           3-16

-------
      Figure 3-2
FRONT WALL-FIRED BOILER
         3-17

-------
M.yiAir»«
                                   Figure 3-3



                      HORIZONTALLY OPPOSED SLAG TAP BOILER





                                      3-18
                                                                                         2421'

-------
        Figure 3-4
TANGENTIALLY FIRED BOILER
          3-19

-------
     As shown in Figure 3-5, coal from the plant stockpile is fed to
each of the several pulverizer systems which serve a boiler unit.
Often there is one pulverizer system for each elevation or group of
burners, with one or more spare systems provided for emergencies.  Air
preheated to as much as 315°C (600°F) by the combustion gases is
supplied to the pulverizers to dry the coal, and to convey the pulverized
fuel to the burners.   Pulverizer air comprises about 15 to 20 percent
of the total combustion air.   Pulverizer air preheat is a necessity
to prevent pulverizer or burner blockage which can be caused by wet
fuel.  Higher moisture content coals require hotter pulverizer air
temperatures.  Pulverized coal is recirculated and mixed with the
incoming feed to promote drying.  The pulverized coalis entrained in
the air stream that flows to an air classifer which separates the
larger particles for return to the pulverizer.  The preparation system
reduces coal particle size so that about 70 percent by weight will
pass through a 200 mesh U.S. sieve.   A 200 mesh screen has 74 micrometer
(0.0029 inch) openings.
     Pulverized coal entrained in 15 to 20 percent of the total combustion
air is conveyed to the individual burner fuel nozzles which direct the
coal and primary air into the combustion chamber.   The burners are
designed to admit controlled quantities of additional air (secondary
air) through separate air ports surrounding or built into the fuel
nozzle.  Some burners are designed to admit controlled additional air
at a second location at the burner (tertiary air).
     Steam generators of modern design can admit controlled additional
air at locations away from the burners.  Riley Stoker modern units are
                                 3-20

-------
        Figure 3-5
Typical pulverized coal fired boiler
           3-21

-------
                                                   o

equipped for underfire, sidefire, and overfire air.   Foster Wheeler

                                                              q

builds modern designs for sidefire, overfire, and curtain air.



Combustion Engineering coal-fired steam generators are equipped for



overfire air.    Babcock and Wilcox modern designs admit combustion



air as primary or secondary air through specially designed burners.



Sidefire air is admitted between burner rows.  Curtain air is directed



parallel to the combustion chamber walls.  Chapter 6 discusses how



combustion air is directed and controlled to reduce NO  emissions.
                                                      X


3.2.2  Emissions



3.2.2.1  General
     Emissions from large fossil fuel-fired steam generators include



particulates, sulfur oxides, oxides of nitrogen ('NO ), carbon monoxide,
                                                   X


halogens, trace metals, and hydrocarbons including polycyclic organic



matter. NO  control has little potential or actual effect on sulfur
          X


oxides, halogen, or trace metal emissions.  Although NO  control has
                                                       X


a tendency to increase particulate, carbon monoxide, and hydrocarbon



emissions, NO  can actually be controlled without significant increases
             X


in these pollutants (see Chapter 6).  Data on the effect of NO
control on polycyclic organic matter emissions is given in Chapter 6.



3.2.2.2  NOX Emissions



     Table 3-10 gives a summary of 1976 estimated NO  emissions from
                                                    X


all sources.    As shown, estimated 1976 emissions from fuel combustion



in stationary sources were 11.8 teragrams 03.1 x 10  tons) per year



as compared with 23.0 teragrams (25.5 x 10  tons) per year from all



sources and were about 51 percent of all NO  emissions.  Table 3-11
                                           X


shows estimated 1976 NO  emissions from fossil fuel combustion sources..
                       X
16
                                   3-22

-------
  As  shown,  estimated 1976 NOX  emissions  from the large fossil  fuel-

  fired  steam  generators  used by  the  electric utility industry  were

  about  6.67 teragrams  (7.35 x  106  tons)  per  year as  compared with about

  8.71 teragrams  (9.60  x  106 tons)  per year from  all  fossil fuel-fired

  sources.  Estimated 1976 electric utility NOY emissions were  about 77
                                             A
  percent of total stationary source fossil fuel  combustion NOX emissions

  and were about 29 percent of 1976 NOX emissions from all sources.


                             TABLE 3-10

        SUMMARY OF 1976 NATIONWIDE NITROGEN OXIDES EMISSIONS16
                          BY SOURCE CATEGORY
 Transportation
  NO  Emissions
Teraebams Per Year
  (10b Tons/Yr)

      10.1
     01.2)
 Stationary Source  Combustion
      11.8
     (13.1)
 Industrial Processes
                                                Q.7
                                               CO. 8).
Solid Waste Disposal
      0.1
      (0-1).
Other
                                                0.3
                                               G0.3J
   Total
                                               23.0
                                              (25.5)
                                3-23

-------
                             TABLE 3-11

       SUMMARY OF 1976 NATIONWIDE NITROGEN OXIDES EMISSIONS
           FROM STATIONARY FOSSIL FUEL COMBUSTION SOURCES
                  16
Electric Utilities
Industry Except Light
 Industry
Res1denti al-Commerci al
and Light Industry


     Total
                         NO  Emissions = Teragrams Per Year (10  Tons/Yr)
                           A
                            Coal
Oil
Gas
Total
4.82
(5.31)
0.54
(0.59)
0.03
(0.03)
5.39
(5.93)
1.06
(1.17)
0.27
(0.30)
0.31
(0.34)
1.64
(1.81)
0.79
( -87)
0.55
(0.61)
0.34
(0.38)
1.68
(1.86)
6.67
(7.35)
1.36
(1.50)
0.68
(0.75)
8.71a
(9.60)
   Does not include gas turbine emissions


     Table 3-12 gives NOV emission factors for dry ash, slag tap, and
                        X

cyclone type large coal-fired steam generators.    Emission factors are

intended for use when emission test data is not available.
                                 3-24

-------
                             TABLE 3-12

         EMISSION FACTORS FOR COAL-FIRED STEAM GENERATORS
                  OF THE ELECTRIC UTILITY INDUSTRY
                                                          17
Boiler Type
                         Grams
                      Per Kilogram
                       Qb/ton)
                                  Emissions
                                                   .(a)
Dry Ash (Dry Bottom)     9
                       (18)
Slag Tap (Wet Bottom)   15
                       (30)
Cyclone
(a)
                        27.5
                        (55)
Nanograms
Per Joule
(lb/106 Btu)
                                              320
                                            (0.75)
                                              540
                                            (1.25)
   980
 (2.29)
                                                           Estimat
3 Percent
QO Dry

  540
                   900
 1640
(b)
     Coal calorific value of 27.900 megajoules per kilogram (12,000 Btu/lb)


     263.36 dry, standard cubic millimetres per joule (9820 DSCF/106 Btu).
     Estimated per method of Subpart D, Part 60, Subchapter C, Chapter 1,
     Title 40, Code of Federal Regulations.

     As shown by Table 3-12, NOX emissions are characteristically

greater from cyclone units than from any other firing configuration

and are usually greater from slag tap units than from dry ash units.

NOX emissions tend to be greater from single wall-fired units than

from horizontally opposed-fired units and tend to be the least from
                       18
tangential-fired units.10  An increase in the total  steam generating

capacity of a unit also tends to increase NOV emissions.  However, no
                                            A
quantitative values are assigned to the foregoing differences.
                                3-25

-------
     As discussed in Chapter 6, NO  emissions from any given coal-
                                  X


fired steam generator design can vary widely depending on the way the



way the unit is operated.
                                 3-26

-------
                   REFERENCES  FOR CHAPTER 3

 1.   Steam  Electric Plant  Factors 1975,  National  Coal  Association,
     Washington,  D.C.,  January 1976.
 2.   Unpublished  calculations  or  data,  Emission Standards  and
     Engineering  Division, Office of Air Quality  Planning  and
     Standards, U.  s. Environmental Protection Agency,  Research
     Triangle Park,  North  Carolina.
 3.   Steam  Electric  Plant  Factors  1976,  National  Coal Association,
     Washington,  D.C.,  1977.
 4.   Stationary Watertube  Boiler  Sales 1976, American Boiler
     Manufacturers Association, Arlington,  Virginia, January 1977.
 5.   United States Energy Through The Year  2000 (Revised), U. S.
     Department of the  Interior, Washington, D.C., December 1975.
 6.   Steam, Thirty-Eighth, 'Edition, Babcock  and Wilcox Company,
     Mew York, New York, 1975.
7.   Steam Electric Plant Construction Cost and Annual Production
     Expenses 1973, Federal Power Commission, Washington, D.C., 1975.
8.  Memorandum, J. Copeland to G. B.  Crane, Meeting with Riley
    Stoker Corporation, February 5, 1976, Emission Standards and
    Engineering Division,  Office of Air Quality Planning and
    Standards,  U, S. Environmental Protection Agency, Research
    Triangle Park, North Carolina, March 29, 1976.
                               3-27

-------
9.   Memorandum, J. Cope!and to R. B. Crane, Trip Report - Meeting
     with Foster Wheeler Energy Corporation of February 6, 1976,
     Emission Standards and Engineering Division, Office of Air
     Quality Planning and Standards, U. S. Environmental Protection
     Agency, Research Triangle Park, North Carolina, March 25, 1976.
10.  Memorandum, J. Cope!and and G. B. Crane to S. T. Cuffe, Trip
     Reoort - Meeting with Combustion Engineering, Incorporated,
     February 19, 1976, Emission Standards and Engineering Division,
     Office of Air Quality Planning and Standards, U. S, Environmental
     Protection Agency, Research Triangle Park, North Carolina,
     April, 1976.
11.  Memorandum, 0, Copeland and H, B. Crane to S, T. Cuffe, Meeting
     with Babcock and Wilcox Company, February 18, 1976, Emission
     Standards and Engineering Division, Office of Air Quality
     Planning and Standards, U. S. Environmental Protection Agency,
     Research Triangle Park, North Carolina, April 15, 1976.
12.  Standards Support and Environmental Impact Statement,
     Lignite-Fired Steam Generators, Emission Standards and
     Engineering Division, Office of Air Quality Planning and
     Standards, U. S. Environmental Protection Agency, Research
     Triangle Park, North Carolina, August, 1976.
13.  Unpublished calculations or data.  Emission Standards and
     Engineering Division, Office of Air Quality Planning and
     Standards, U. S. Environmental Protection Agency, Research
     Triangle Park, North Carolina.
                               3-28

-------
14.  Parks, B. C. and O'Donnell, H. J., Petrography of American Coals,
     U. S. Bureau of Mines Bulletin 550, 1.957.
15.  Mineral Matter and Trace Elements in U. S. Coals, Office of Coal
     Research and Development, Report Mo. 61, Pennsylvania State
     University, 1972.
16.  Unpublished data, National Air Data Branch, Monitoring and
     Data Analysis Division, Office of Air Quality Planning and
     Standards, u. S.  Environmental Protection Agency, Research
     Triangle Park, North. Carolina, July, 1976.
17.  Compilation of Air Pollutant Emission Factors, Part A, Second
     Edition, AP-42, U. S. Environmental Protection Agency, Research
     Triangle Park, North Carolina, February 1976.
18.  Field Testing:  Application of Combustion Modifications to
     Control NOV Emissions from Utility Boilers, EPA-65Q/2-74-066,   •
               A
     U. S. Environmental  Protection Agency,  Research Triangle Park,
     North Carolina, June, 1974.
                               3-29

-------

-------
           4.  N0x CONTROL TECHNOLOGY  FOR PULVERIZED  COAL
               (•EXCEPT LIGNITE)-FIRED  STEAM GENERATORS

4.1  CONTROL PRINCIPLES FOR NO
                              A
     N0x forms via two distinct mechanisms; one in which elemental
nitrogen is taken from the air and the other in which chemically
combined nitrogen is taken from the fuel.
     Fixation of nitrogen of the air can be limited by reducing the
level of thermal excitation due to the flame temperature thereby
minimizing the Zel 'dovich reactions:
     02 + M ->0 + 0 + M
     0  +
              NO + N
       +  02-> NO + 0
                                                 1
where M represents the hydrocarbons  in the flame.'  Thermal  excitation
can be reduced by (a) flue gas recirculation,  (b) staged combustion,
(c) water or steam injection, (d) reduced air  preheat,  or  (e)  reduced
heat release rate.
     Oxidation of fuel nitrogen may  be responsible for  as much as 80-90
percent of the total N0x emissions from pulverized coal firing.2
Reactions between fuel nitrogen and  oxygen are retarded by burning as
much of the fuel as possible in an oxygen deficient atmosphere.2  This
is accomplished by limiting the combustion air supplied at or near the
                           4-1

-------
burners and by directing the air to limit high temperature mixing of



volatilized fuel nitrogen and air.  When the fuel nitrogen is volatilized



in the absence of air and at high temperature, most of the nitrogen

                                                                        2

which is part of hydrocarbon molecules is reduced to molecular nitrogen.



Further NOV formation is limited to that formed by fixation of nitrogen
          A
in the air according to the Zel 'dovich reactions.
                                                  1
     The oxygen deficient conditions which limit NO  formation from
                                                   A


reactions between fuel nitrogen and oxygen are poor conditions for



complete fuel oxidation.  Consequently, there must finally be intimate



contact between combustibles and oxygen before the gases leave the



furnace. This is accomplished by surrounding the fuel rich flame with



an air rich zone.  As the fuel rich gases cool by radiating thermal



energy to surrounding colder surfaces, the gases flow into the air rich



zone and combustion is completed at temperatures less favorable for NOV
                                                                      X


formation.  This is known as staged combustion.  As discussed in Section



4.3, staged combustion is accomplished in more than one way.



     Table 4-1 summarizes NO  control methods.  In Sections 4.3, 4.4,
                            A


and 4.5 of this chaoter,the most viable control methods are discussed.



More data on control methods are given in Chapter 6.



4.2  CONTROL METHODS FOR PULVERIZED COAL-FIRED UTILITY BOILERS



     Because of very high efficiency losses, water injection and reduced



combustion air preheat are not competitive MO  control methods for
                                             X


utility boilers.  Flue gas recirculation is ineffective for controlling

                   3

fuel NOV from coal.   Control of coal nitrogen content is not practical
       A


because the nitrogen content of most coals is in a narrow range between



1.2 and 2.1 oercent. '  Although some stack gas cleaning systems have
                               4-2

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-------
been applied to combustion sources in Japan, experience with NOX gas



cleaning systems for pulverized coal-fired sources is so limited that



this technique currently is not considered an adequately demonstrated

                                                             5

NO  control alternative for new source performance standards.   Therefore,
  /\

the control methods of Table 4-1 to be considered in further detail for



pulverized coal are:



     ' Staged Combustion



     ' Low Excess Air



     ' Reduced Heat Release Rate



     " Combined Techniques



4.3  STAGED COMBUSTION



     A typical utility boiler operates with an array of burners, each



of which operates with a flame  "basket" of overall excess air equal to



the total excess air of the entire boiler.  As discussed in  Chapter 6,



the flame characteristics  differ for individual boiler manufacturer's



designs*.  Staged combustion is  accomplished by redistributing the  air



flow such that a cooler secondary combustion zone is encountered by the



combustion gases after they leave the flame basket.  Staged  combustion



has two effects on NO  :
                     **


     1.  Fuel  NOV is reduced because less oxygen  is  available
                A


         during volatilization.



     2.  Thermal NOV is reduced because the temperature does not
                   X


         reach  as high a  peak  as when all the  heat  release



         occurs in one stage.
                                 4-4

-------
 Two methods of air redistribution are shown  schematically in  Figure  4-
 1.  Starting from the normal  air/fuel  ratio at the  burners,  staging can
 be  accomplished either by maldistributing air (overfire  air port), or
 by  maldistributing fuel  (burner out of service.).   The extent of staged
 air can be conveniently  indexed by the fraction  of stoichiometrically-
 required air remaining at the  burner  flame baskets.   For example,
 suppose a boiler operating with 15 percent excess  air has five operating
 burner levels  with air supplied to six levels.   Then  one-sixth of the
 air supply is  staged,  leaving  the burners (115 x 5/6) or 95 percent of
 stoichiometric air at  the  burners.  This type of staged  combustion has
 shown  reductions  of 20-40  percent when  applied to  pulverized  coal-fired
 utility boilers.3
     Staged  combustion conditions  can  also be created by special burner
 designs.   Figure 4-2 shows the  burner  used by one  of  the four major
 utility boiler manufacturers".   The burner produces a  lazy,, fuel-rich
 flame  surrounded by an air envelope.   Limited testing indicates that
 the burner can reduce NOX emissions by as much as  50 percent.6'7
 4.4  LOW  EXCESS AIR
     In addition to the air needed to complete combustion, about 10 to
 20 nercent excess air is added  to utility boilers to cover normal - 3
 percent fluctuations in excess air and to aid soot burnout.8
     At times excess air is needed to  increase convective heat transfer,
 to cool the slag below the softening point, or to minimize tube wastage
 (corrosion).9'10'11'12  The foregoing  factors are discussed  in Chapter
6.  Subject to these operating constraints, if excess  air can  be  minimized
then NOV is reduced for two reasons:
       A                                                    ,
                               4-5

-------
I     I   AIR
         FUEL
NORMAL
FIRING
STAGED BY
BURNERS OUT
OF SERVICE c
STAGED BY
OVERFIRE.
  AIR   d
Figure 4-1.  Variations in firing techniques for^staged
    combustion of NOx emissions from existing units.
a Length equals proportionate quantities of fuel and air.

  All levels of burners firing fuel.

c No fuel fired on upper burner levels.

^ All levels of burners firing fuel, overfire air added.
                    4-6

-------
                                                     £
                                                     6
                                                     z


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                                                     'u
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Figure 4-2
  4-7

-------
     1.   Fuel NO  is reduced because less oxygen is available during
                 A


           volatilization.



     2.   Thermal NO  is reduced because the controlling Zel 'dovich
                    A


          reaction, 0 + Np  NO + N, is retarded by low oxygen radical



          concentrations.



It should be noted that under ideal conditions, well mixed, adiabatic



combustion systems respond adversely to lower excess air, giving higher

                                                 13

NO because of higher adiabatic flame temperature.    However, in reality,



utility boiler systems usually show NO  reduction with low excess air.
                                      X


Emission of NO  from coal-fired boilers as a function of excess air are
              x
                    3

shown in Figure 4-3.   As shown, the effectiveness of reduced excess



air varies for individual boilers.  As discussed in Chapter 6, the test



conditions shown in Figure 4-3 may not be suitable for long term operations



because of fuel burnout, slagging, carbon monoxide, or tube wastage



(corrosion) problems.



4.5  REDUCED HEAT RELEASE RATE



     Emission of NO  is also limited by reducing heat release rate.
                   A


Prior to the Federal New Source Performance Standards for NOV pro-
                                                            X


mulgated in 1971, all four major boiler manufacturers were reducing



combustion chamber size in relation to firing rate, thereby increasing


                   Q in n i?
heat release rates. '1U'"5U1  As a result of the 1971 standards, all



four manufacturers decided to use more conservative design criteria



which resulted in increases in combustion chamber size ranging from 15



to 50 percent. Reducing heat release rate reduces combustion gas



temperatures more rapidly, thereby reducing the rate and mass of formation
                                4-8

-------
   900
   800
   700
   600
CO
S
PM
  500
  400
   300
                                                     Front Wall Fired
                                                     Opposed Wall Fired



                                                     Tangential Fired


                                                               I
                 10
15          20          25

      PERCENT EXCESS AIR
                                                              30
35
            Figure 4-3  Relationship between PPM NOx and percent excess

                       air for selected coal-fired boilers.3

                                     4-9

-------
of NO  from the reactions between the nitrogen of the combustion air
     /v
and oxygen.
4.6  COMBINED TECHNIQUES
     The most effective, viable NO  control technique for pulverized
                                  A
coal-fired steam generators is to employ a combination of staged
combustion, lower excess air, and reduced heat release rate techniques.
Chapter 6 discusses the various techniques used by the four major
boiler manufacturers.
                              4-10

-------
                       REFERENCES  FOR  CHAPTER 4
 1.   Zel  'dovich, Ya.  B.,  P. Ya. Sadovnikov, D. A. Frank-Kamenetsku.,
     Oxidation of Nitrogen in Combustion, Academy of Sciences of the
     U.S.S.R., Institue of Chemical Physics, Moscow-Leningrad,
     Translated by M.  Shelef, Scientific Research Staff, Ford Motor
                      i
     Company, 1947.
 2.   Pershing, D. W.,  G. B. Martin, and E. E. Berkau, Influence of
     Design Variables  on the Production of Thermal and Fuel NO From
     Residual Oil and  Coal Combustion, Presented at the 66th Annual
     Meeting of the American Institute of Chemical Engineers,
     Philadelphia, Pennsylvania, November 11-15, 1973.
 3.   Field Testing:  Application of Combustion Modifications to Control
     N0x Emissions from Utility Boilers, EPA-650/2-74-066,  U. S.  .
     Environmental Protection Agency,  Research Triangle Park, North
     Carolina, June, 1974.'
4.   Parks, B. C.  and A. J. O'Connell, Petrography of American Coals,
     U. S. Bureau of Mines Bulletin 550, 1957.
5.  Ando, J., NOX Abatement Technology in Japan for Stationary
    Sources, Chuo University,  Kasuga, Bunkyo-Ku,  Tokyo,  March,  1975.
6.  A. R. Crawford, et. al,  The Effect of Combustion Modification  on
     Pollutants  and Equipment Performance  of Power Generation Equipment,
    Exxon Research and Engineering Company,  Linden,  New  Jersey,
    September,  1975.
7.  Campobenedetto, E. J., The  Dual Register Pulverized  Coal  Burners -
    Field Test  Results,  Presented  at  the  Engineering Foundation  Conference
    on Clean Combustion of Coal, Franklin  Pierce  College,  Rindge,  New
    Hampshire, July 31 to  August 5, 1977.
                               4-11

-------
8.   Steam, Babcock and Wilcox Company,  New York,  New York,  1975.
9.   Memorandum, J. Copeland to G.  B.  Crane, Trip  Report - Meeting  with
     Riley Stoker Corporation, February  5,  1976,  Emission Standards and
     Engineering Division, Office of Air Quality  Planning and  Standards,
     U.S. Environmental Protection Agency,  Research Triangle Park,
     North Carolina, March 29, 1976.
 10. Memorandum, J. Copeland to G.  B.  Crane, Trip  Report - Meeting  with
     Foster Wheeler Energy Corporation of February 6, 1976,  Emission
     Standards and Engineering Division, Office of Air Quality Planning
     and Standards, U.  S.  Environmental  Protection Agency, Research
     Triangle Park, North  Carolina, March 25, 1976.
11.  Memorandum, J. Copeland and 6. B. Crane to S. T. Cuffe, Trip
     Report - Meeting with Combustion Engineering, Incorporated,
     February 19, 1976, Emission Standards  and Engineering Division,
     Office of Air Quality Planning and  Standards, U. S.  Environmental
     Protection Agency, Research Triangle Park, North Carolina,
     April, 1976.
12.  Memorandum, J. Copeland and G. B. Crane to S. T. Cuffe, Meeting
     with Babcock and Wilcox Company,  February 18, 1976,  Emission
     Standards and Engineering Division, Office of Air Quality Planning
     and Standards, U.S. Environmental Protection  Agency, Research
     Triangle Park, North  Carolina, April 15, 1976.
13.  Draft of Standards Support and Environmental  Impact Statement
     for Lignite-Fired Steam Generators, Emission  Standards  and
     Engineering Division, U.S. Environmental Protection Agency,
     Research Triangle Park, North Carolina, 1976.
                                4-12

-------
                  5.  MODIFICATION AND RECONSTRUCTION
 5.1  GENERAL
      The terms modification and reconstruction have special  meanings
 when used in new source performance standards.  These terms  are clarified
 in Subpart A, Part 60,  Subchapter C, Chapter 1, Title 40,  Code of
 Federal  Regulations.   In general  terms,  a modification is  a  selected
 type of change which  increases  the emission  of selected pollutants  to
 the atmosphere.   When the alterations  are limited,  new source  performance
 standards  only require  that increases  in the emission of selected
 pollutants  be prevented.   In  general terms,  reconstruction is  a  change
 which  is so substantial  as  to class  the  source as a  new source  rather
 than an altered  existing  source.   In this  case,  the  source becomes
 subject to  all the  limits of  the  new source  performance standard.
 5.2  MODIFICATION
 5.2.1  Scope  and Effect of  Modifcation Regulations
     A modification means any change in  the method of operation of an
 existing facility which increases the amount of any air pollutant (to
which a standard applies) emitted into the atmosphere by that facility
or which results in the emission of any air pollutant (to which a
standard applies) into the atmosphere not previously emitted. The term
modification is further limited  by exempting  selected types of changes.
                                5-1

-------
from the applicability of new source performance standards.
     Normally, all that is required of an existing facility i,s that
emissions of a specific pollutant after alteration be no more than they
were before alteration.  These modification regulations only apply to
the pollutants of the new source standard and apply on a pollutant-by-
pollutant basis.  In rare cases, emission of one or more pollutants may
be less than the limit of a new source performance standard prior to
the alteration.  In this situation, an emission increase is allowed, up
the limit of the applicable new source performance standard.  Consequently,
when changes are made which cause an existing source to become subject
to a new source performance standard, emission control systems are
normally altered to prevent emission increases.  In exceptional circumstances,
no additional air pollution control equipment may be needed to prevent
an emission increase or; limiting emissions to the level of the new
source performance standard may be less costly than preventing an
emission increase.
     Adding an affected facility to a plant or replacing an existing
facility within a plant would not cause other unchanged existing facilities
within the plant to become subject to the no emission increase rule.
Where a plant has several existing facilities, the no emission increase
rule may not apply to an altered existing facility if net  plant emissions
are not increased.  For example, if emissions of pollutant A are increased
by a change to facility 1 in a plant, this emission increase is allowed
if emissions of pollutant A from facility 2 are decreased  by an amount
equal to or exceeding  the amount of increase from facility 1.
                                5-2

-------
      Emission increases are allowed if such increases are caused by
 routine maintenance,  repair, and replacement.   Emission increases are
 also allowed if caused by increases in production rate which  can be
 accomplished without  major capital  expenditure.   Increases in emissions
 caused  by longer operating hours are also  exempted from the rule on no
 emission increase.  Another exemption is for the  use  of an alternative
 fuel  or.raw  material  if—prior  to the date any  standard becomes  applicable-
 the  existing facility was  designed  to accommodate that  alternative  use.
 Conversion to coal as  stipulated in  Section lll(a)(8)  of the  Clean  Air
 Amendments of 1977 is  not  considered a modification.   Emission increases
 caused  by the addition  or  use of any system whose primary function  is
 the  reduction of air  pollutants,  are also  exempt  from the no  emission
 increase  rule.
 5.2.2  Modified  Pulverized  Coal-Fired Steam Generators
     For  the  purposes of determining  if modification regulations apply
 or should apply,  the pulverized  coal-fired  steam  generator system is
 defined as including the following major components.
     a)  pulverizer system
     b)  combustion air system
     c)  steam generation system
     d)  draft system
     e)  fuel combustion system
     The major points  which define the inlets  to the affected  facility
are:
                               5-3

-------
      1.  The inlet to the pumps which feed water at steam generator
          pressure.
      2.  The inlet to the bins which directly feed the pulverized or
          stoker systems unless the bins are sized to store more than enough
          coal to operate the steam generator 72 hours at full  load.   When
          large bins are installed, the inlet to the affected facility is the
          outlet of the bins feeding the pulverizer or stoker systems.
      3.  The combustion air intakes.
      The major points  which define the outlets  of the affected  facility  are:
      1.  Any steam outlet
      2.   Any bottom ash outlet
      3.   The outlet of the  last  system installed  before  the  stack, such
          as  the  outlet of any  induced  draft  fan.
All components of  the  steam  generator  installed between  these points are
part  of the  affected facility  except any air pollution control systems, such
as electrostatic precipitators, mechanical collectors, baghouses, or
scrubbers.
     Replacement of the pulverizer system with a similar system or
replacement of component parts of the pulverizer system with similar
parts would not be considered a modified source.  However, replacement
or redesign of the pulverizer system which would substantially change
                               5-4

-------
 the.ph.ys.lcal characteristics of the pulverized.cgal may he a change
 where modification regulations apply.
      Likewise changes in the design of the combustion air system
 which, change the way- combustion air is: Introduced to the combustion
 chamber would cause a source to be evaluated to determine if
 modification regulations shmild apply.  Changing the combustion air
 damper settings is not a modification as long as no redesign of the
 combustion air system is involved.
      The steam generation system includes the feedwater treatment
 system,  watertubes,  economizer, and superheat and reheat sections.
 Maintenance of these components is  not a  modification.   Major redesign
 of these parts  would cause  a  source to be evaluated to  determine if
 modification  regulations should apply.  It is doubtful  that  redesign
 of the feedwater  treatment  system,  the  economizer,  or the superheat
 or reheat sections would affect NQ^ emissions.  Redesign of the  steam
 generation  system components which  affect  combustion temperatures-
 such as  the waterwall sections—could change  NQV emission characteristics.
                                               -A
     Redesign of  the draft  system such as  changing  from induced  draft
 conditions to pressurized firing conditions would cause a source to
 be evaluated to determine if modification  regulations should apply.
     Changes in the fuel combustion system which, would be modifications
 are :
     al  changes in the number of burners
     b)  changes in the type of burners
and  c}  changes in the:location of burners.

-------
      Although a change to a different nitrogen content or a different
 moisture content coal or a switch from lignite to non-lignite coal
 might be considered a modification, these changes are exempted from
 modification evaluation by current regulations.1
      Sources, which by reason of the date of new  construction, are
 subject to the NO  new source performance standard for coal  combustion
                  A
 continue to be subject to the original  standard in spite of any subsequent
 changes in solid fossil  fuels or alteration.   In  cases where the original
 NOX standard is revised  to become more  restrictive,  none of the foregoing
 discussed modifications  should cause the  source regulated by the original
 NOX standard to become subject to the more restrictive standard unless
 the modifications are so extensive as to  be classed  as reconstruction.
 (See Section 5.3).
 5.2.3  Modification of Oil-  or Gas-Fired  Steam Generators to Fire Coal
      The  discussion of Section 5.2.3 is limited to modifications which
 would cause a source to  become subject to  NO   new source performance
                                            J\
 standard  modification regulations  for large pulverized coal  (other  than
 lignite)-fired  steam generators.
      Alterations  which might  cause  an existing  oil or  gas-fired  steam
 generator to  become  subject to  NOV  modification regulations  for  coal-
                                  X
 fired steam generators are alterations involving  a switch  from gas  or
 oil  to  coal.  Current regulations provide that  if  the  oil  or gas-fired
 source  is  already designed to fire  coal, a  switch  to coal  does not
 cause the  source  to  become subject  to coal-fired steam generator NO
                                                                    A
modification  regulations.  In addition, Section lll(j),(8)  of the Clean
Air Amendments of 1977 exempts from the modification provisions of the
                               5-6

-------
 Amendments  certain sources  switching  from  oil  or  gas  to  coal.   This



 latter category of sources  is  described  in general  terms  as  sources



 required to switch to  coal  under  Section 2(a)  of  the  Energy  Supply and



 Environmental  Coordination  Act of 1974.  (The  reader  is  cautioned to



 seek  competent legal advice—such as  from  the  Office  of  Enforcement and



 General  Counsel,  U. S.  Environmental  Protection Agency, Washington,



 D.C.--before assuming  that  a source switching  from  oil or gas to coal



 is  exempted from  the modification provisions of the Clean Air Amendments.)



      Sources switching  from oil or gas to  coal which  are not otherwise



 excepted by U.  S.  Environmental Protection Agency regulations or by law



 would be subject  to NOX new source performance standard modification



 regulations.   Because oil and  gas-fired  steam generators characteristically



 emit  less NOX  than coal-fired  steam generators, a switch from oil or



 gas to coal would  normally  increase NO   emission concentrations.
                                      A


 However,  the total rate of  NO  emissions might not be increased, because
                             A


 when  steam  generators which are originally designed for oil  or gas



 firing and  are  not designed for coal  firing are converted to fire coal,



 it  is usually  necessary to substantially reduce steam generator capacity



 and heat input.  Consequently,  altering an  oil  or gas-fired  steam



 generator to fire coal  may not increase the mass of NO  emissions even
                                                      A


 if there is an  increase in NOX  emission concentrations.   Subpart A,



 Part 60, Subchapter C,  Chapter 1,  Title 40, Code of Federal  Regulations,



describes the procedure for determining if  an NO  emission increase  has
                                                A

occurred.



     The cost of modifying an oil  or  gas-fired  steam generator  to



fire coal may be so substantial as to  class the source as  a  reconstructed
                                5-7

-------
 source (see Section 5.3).                                          .
      Rulings on whether alterations of fossil  fuel-fired steam generators
 constitute a modification  can be obtained by contacting a U.  S.  Environ-
 mental  Protection Agency Regional  Office of Enforcement.
 5.3  RECONSTRUCTION
      The  purpose of reconstruction regulations is  to prevent  the
 perpetuation of existing sources.   When modifications or replacements
 become  so extensive as  to  create an essentially new source, the  source
 becomes a reconstructed source and is  subject  to the new source  per-
 formance  standards which apply at  the  time of  initiation of reconstruction,
      According  to the provisions of Subpart A, Part 60,  Subchapter C,
 Chapter 1, Title 40, Code  of  Federal Regulations,  a facility  becomes a
 reconstructed source irrespective  of any change in emission rate when
      a)   the fixed capital cost of the  new components  exceeds  50 percent
 of  the fixed capital cost  that would be  required to  construct  a  comparable
 entirely  new facility and
      b)   it  is  technologically and  economically feasible  to meet
 applicable standards.
     Rulings  on whether  changes  to  a fossil fuel-fired steam generator
 constitute reconstruction can  be obtained  by contacting a U.  S.  Environ-
mental Protection Agency Regional Office of Enforcement.
                               5-.8

-------
                     REFERENCES FOR CHAPTER 5
1.  Subpart A, Part 60, Subchapter C, Chapter 1, Title 40,
Code of Federal Regulations.
                               5-9

-------
-

-------
                      6.   EMISSION CONTROL SYSTEMS
.6.1   GENERAL
      The discussion of Chapter 6 is limited to pulverized coal-fired
 steam generators other than those firing lignite.   A separate document
 has  been prepared for pulverized lignite combustion.1   Recommendations
 for  the few stoker-fired units larger than 73 megawatts (250 xlO6
 Btu/hr) heat input are being developed separately in conjunction with
 recommendations  for smaller stoker-fired units.
      There are four manufacturers who now construct nearly all  of the
 new  pulverized coal-fired steam generators.   These manufacturers are
 Babcock & Wilcox Company, Combustion  Engineering,  Incorporated,  Foster
 Wheeler Energy Corporation,  and Riley Stoker Corporation.  All  are
 currently furnishing or  are  constructing units  designed to meet  the
 current Federal  NOX new  source performance standard of  300 nanograms
 per  joule (0.7 lb/106 Btu).2'3'4'5'6
      As documented in this  chapter, Combustion  Engineering (CE)  pulverized
 coal-fired steam generators  are capable  of limiting NO   emissions  to  a
                                                      X
 level  less than  210 nanograms  per joule  (0.5 lb/106 Btu) without any  of
 the  following  adverse side effects if subbituminous coal is  fired.
      a)  severe  tube wastage (corrosion)
                              6-1

-------
      b)  unmanageable slagging
      c)  loss of boiler efficiency
      d)  loss of particulate control  efficiency
      e)  increased ash combustible content
      f)  increased carbon  monoxide emissions
      g)  increased hydrocarbon or polycyclic  organic matter  emissions
 or   h)  increased tubine  blade wear  or  loss  of power  generating
          efficiency caused by low superheat temperature
      If bituminous coal  is fired,  a safer  lower limit  of  NO   control for
                                                           /\
 CE units is  a level  of  260 nanograms  per joule  (0.6 lb/106 Btu) because
 of the  potential  danger of tube wastage  from  reducing  combustion gas
 atmospheres.   (See Chapter 4).
     Although it  is  not  as  well  documented that Babcock and  Wilcox,
 Foster  Wheeler, and  Riley  Stoker units are equally effective, it is
 likely  these  three manufacturers  are  capable  of furnishing units which
will perform  as well as  Combustion  Engineering  units.
 6.2  NOX CONTROL TECHNIQUES  FOR  INDIVIDUAL BOILER MANUFACTURER
 6.2.1   Babcock and Wilcox
     Modern Babcock  and  Wilcox  (B&W)  pulverized  coal-fired steam generators
designed to meet the current new source performance standard for NO  are
                                                                   X
equipped with burners which are specially designed to limit NO
                                                              A
emissions.  Figure 6-1 shows a cutaway of the special  burner.7  Figure
6-2 shows how the  burner is designed  to produce a lazy, fuel-rich  flame
surrounded by an air envelope.   The fuel-rich gases diffuse into  the
air-rich zone and  are cooled by radiation and dilution.  Babcock and
Wilcox claim that the new burner design will  permit furnaces  to be
                                6-2

-------
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C2J
 6-3

-------
                                                       C
                                                       o
                                                      '
                                                      .12


                                                       CD
                                                       X
                                                       O
                                                      z:


                                                      • o
                                                       o
                                                       C
                                                       0)
                                                       C
                                                      00
Figure 6-2
 6-4

-------
maintained  in  an  oxidizing  environment, thus minimizing  slagging  and


reducing  the potential  for  furnace wall corrosion when high  sulfur

                          Q
bituminous  coal is  burned.



     Comprehensive  test data are available for a 270 megawatt unit


(retrofitted), the  first: Babcock and Wilcox unit to be equipped with


specially designed  burners.   These burners are similar  to,  but are not


identical with, the burners currently being furnished on modern Babcock


and Wilcox  pulverized coal-fired steam generators.


     Table  6-1 shows full load NO  emissions from the retrofitted
                                 A


boiler for  a wide variety of operating conditions.9  As  shown, NO
                                                                 X

emission  levels ranged  from 167 to 233 nanograms per joule (0.39-0.54


lb/10  Btu) and were the lowest at oxygen contents less than 2.5 percent.


Table 6-2 shows that boiler efficiency was about the same in the normal

                            9
and low N0x operating modes.   Fly ash carbon averaged 1.8 percent in


the normal mode as  compared with 4.4 percent in the low NO  mode.9
                                                          X

Table 6-3 shows that decreasing levels of oxygen may increase carbon


monoxide concentrations while reducing emissions of NO .9
                                                      X

     Table 6-4 compares corrosion test coupon weight losses for Boiler


Nos. 1  and 2.    Boiler No.  1 is similar to Boiler No.  2 except that


Boiler Mo. 1 is equipped with the modern specially designed B&W burners.


Statistical  analysis shows that test coupon losses for Boiler No.  1


(low N0x) were significantly greater than test coupon  losses for Boiler


No. 2 (normal)  when analyzed at the 95 percent confidence level.


     Low NOX operation of Boiler No.  1  of Table 6-4 did not cause  any

                      g
unmanageable slagging.    Superheat temperatures were maintained  above


design  limits  in the low N0x mode.9  There was no  significant increase


in particulate  emissions,



                               6-5

-------
                          TABLE  6-1

        Full  Load NOX Emissions  from a  270 Megawatt?
Babcock and Wilcox Pulverized Coal-Fired Steam Generator
         Retrofitted with Specially Designed Burners
Air Register
Secondary
Air
70

70

50

30

TOO


50

50

30

100

Settings -Percent
Tertiary
Air .
100

100

100

100

100

«
100

50

50

50

Open
Vanes
90

90

100

100

100


90

90

90

90

Percent By
Volume
4.3

2.4

2.4

2.6

2.4


2.3

2.5

2.2

2.0

NOX
nanograms
per ioule
(lb/10° Btu)
233
CO. 54)
167
(0.39)
173
(0.40)
197
(0.46)
201
(0.47)

191
(0.44)
217
(0.51)
187
(0.44)
177
(0.41)
                              6-6

-------
                 TAB.LE 6-2

ply Ash. Carbon, Efficiency, Oxygen, and NOX at Full Load
          for a 270 Megawatt Babcock and Wtlcox
   Modern Design Pulverized Coal-Fired Steam Generator

Firing
Mode
Normal
Normal
Normal
Normal
Low. NOV
A
Low NOV
X
Low NOV
-A

Carbon in
Fly Ash 	
% by Weight'
'2.7
1.1
1.7
2.1
5.7
3.4
4.1

Boiler
Efficiency
Percent
89.8
90,1
89.9
89.2
89.2
89.6
89.8

Oxygen
Percent by Volume
4.2
4.2
4.1
4.3
3.9
3.9
3.9

N°X
Nanograms per
Joule
(lb/106 Btu)
350
(0.81)
350
(0.81)
343
(0.80)
363
(0.85)
209
(0.49)
189
(0.44)
189
(0.44)
                  6-7

-------
                                TABLE 6-3

         Carbon Monoxide Emissions from a 270 Megawatt Babcock 9
             and Wilcox Modern Design Pulverized Coal-Fired
         Steam Generator at Various Oxygen, NOX, and Load Levels
   Load
Megawatts
  Oxygen
Percent by
  Volume
       NOX
  Nanograms per
Joule (Ib/lQo Btu)
Carbon' Monoxide
    ppm at
 3 percent 0
   270


   270


   190
    4.3


    2.4


    1.6
       233
      (0.54)

       167
      (0.39)

       109
      (0.25)
      26


      65


     329
                                    6-8

-------
                   TABLE 6-4

Corrosion Test Data for Two Babcock and Wilcox 9
    Pulverized Coal-Fired Steam Generators
Boiler No.
2 (old style)
2
2
2
2
2
Average
1 (Modern)
1
1
1
1
1
Average
Probe No.
3
3
3
4
4
4
v
2
2
2
1
1
1

Firing Condition
Normal
Normal
Normal
Normal
Normal
Normal

Low NOY
/\
Low NOV
X
Low NOX
Low NOX
Low NOX
Low NOX

Coupon Loss
Micrometres per year
(mils/year)
262
(10.3)
185
( 7.3).
259
(10.2)
203
( 8.0)
160
( 6.3)
152
(6.0)
204
( 8.0)
508
(20.0)
312
(12.3)
264
(10.4)
257
UO.l)
180
( 7.1)
290
(11.4)
302
(11.9)
                      6-9

-------
     Table 6-5 summarizes other test data on modern Babcock and Wilcox
                            8      •      '    "  '     *
coal-fired steam generators.   As shown, controlled NO  emissions
ranged from 140 to 200 nanograms per joule (0.33-0.47 lb/106 Btu)
showing that B&W coal-fired steam generators equipped with specially
designed burners are capable of limiting NO  emissions .to low levels.
                                           X
                               TABLE 6-5
           SUMMARY OF NO  EMISSION CONTROL DATA FOR MODERN
           BABCOCK AND WTLCOX COAL-FIRED STEAM GENERATORS
              EQUIPPED WITH SPECIALLY DESIGNED BURNERS
                                                   8
Plant No.
Plant Size
   MW
  90
NO  Emission Control Level
   Nanograms per joule
	(1b/10° Btu)	
      142 (0.33)a
                   250
                             202 (0.47)
                   700
                             150 (0.35)
a  Babcock and Wilcox  Report.  Test method not given.
     Table 6-6 shows polycyclic organic matter emissions from an old
style, horizontally opposed, 560 megawatt Babcock and Wilcox pulverized
coal-fired steam generator.    The steam generator was operated with:
     1.  All burners in service
     2.  Selected burners on air only
     3.  Flue gas recirculation, all burners in service
     4.  Flue gas recirculation, selected burners on air only.
                               6-10

-------







































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The data indicate that two stage combustion with selected burners out
of service may increase polycyclic organic matter emissions from old
Babcock and Wilcox steam generators equipped with old style burners.
However, this data is insufficient to draw any conclusions on the
effect of modern, low NO  B&W burners on polycyclic organic matter
                        X
emissions.
     Babcock and Wilcox is now building a new unit which will be required
to comply with the State of New Mexico emission limitation of 193 ng/J
(0.45 Ib/million Btu).    The unit will burn subbituminous coal with a
heat content of about 22.6 kilojoules per kilogram (9700 Btu/lb) and a
                                 12
sulfur content of 0.9% by weight.    Construction is scheduled for
completion in May, 1979.  Babcock and Wilcox would not have contracted
to furnish this multimillion dollar unit unless they were.sure of their
capabilities for designing a unit which would comply with the State of
New Mexico NO  regulation.
             /\
6.E.2  Combustion Engineering, Incorporated
     Modern design Combustion Engineering (CE) pulverized coal-fired
steam generators are much the same as the old style designs except
modern units are equipped for overfire air and are 15 to 20 percent
larger.  Figure 6-3 shows a cutaway of a modern design unit.  The
tangential design creates a swirling ball of fuel rich combustion gases
in the firing zone surrounded by an air rich zone.  As the gases diffuse
toward the walls, they are cooled by radiation and dilution.  With
overfire air, less combustion air can be used in the firing zone without
reducing total combustion air.  This limits NO  formation.   The best
                                              X
full load NO  emission control is achieved when the overfire air dampers
            y\                          •
                                6-12

-------
F- FUEL  AND AIR
A-AIR
0-OVERFIRE  AIR
                 Figure  6-3
 Schematic Overfire Air System, Barry No. 2

                     6-13'

-------
              r\ TO T A
are wide open. '       Both old style and modern design tangential
units are equipped with burners which can be tilted upward or downward.
The modern design units are equipped so that the overfire air nozzles
can be tilted upward or downward independent of the burner nozzles.
By adjusting the overfire air nozzle and burner nozzle tilt, low NO
                                                                   A
emission levels are achieved without significant increases in carbon
monoxide concentrations or the combustible content of the ash, and
superheat and reheat temperatures can be maintained above minimum
                   91314
design temperature. '  '    It is logical to conclude that if carbon
monoxide emissions are not increased, hydrocarbon or polycyclic organic
matter emissions are not increased.
     The U.S. Environmental Protection Agency (EPA) has tested five
Combustion Engineering modern design pulverized coal-fired steam
           9 13 14
generators. »IO»'^  in addition, Combustion Engineering has furnished
EPA the results of eleven more tests of tangential pulverized coal-
fired (other than lignite-fired) steam generators.    The Combustion
Enginering data and the EPA data used to evaluate Combustion Engi-
neering units are contained in or are referenced in Appendix C.
     As shown in Table 6-7, full load NO  emission levels measured
                                        A
during the five U.S. Environmental  Protection Agency test projects
involving five different sources ranged from 109 to 236 nanograms per
joule (0.25-0.55 lb/10  Btu) when the sources were operated at combustion
gas oxygen contents less than 5 percent and with overfire air damper
                                  9 13 14
settings at least 50 percent open.  '  '
     For all five units there was no significant difference between
                                                                g i "3 1 n
the fly ash carbon content during low NOV and normal operations, '' *
                                        X
                               6-14

-------


























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-------
Except for the Plant C test, no significant increase in CO emissions was



measured.9'13'1'*  For the Plant G tests, CO emissions were 330 ppm at 3



percent oxygen in the low NO  mode as compared with 64 ppm at 3 percent
                            A                            '  '

                                 9
oxygen in the normal firing mode.   Neither of these CO concentrations are



high enough to cause air pollution problems.



     Boiler efficiencies were measured during three of the five test



projects.9'13'14  As shown by Table 6-8, boiler efficiency was about the



same with low NO  operations as with normal operations.  Under field
                X


conditions boiler efficiency should be slightly higher in the low NO  mode
                                                                    A


than under normal conditions because more careful combustion control is



required for low NO  control than for normal boiler operation.
                   J\


     Table 6-9 , 6-10, 6-11, and 6-12  show corrosion test results for


                                   9 T3 14
plants A, C, D, and E of Table 6-7. '  *    No corrosion data are reported



for plant B of Table 6-7.  The tests involved measuring metal loss from



coupons exposed at temperatures ranging from 315°C to 400°C  (600-750°F).



Coupon metal loss for the Plant A tests of Table 6-9 were statistically



greater during low NO  operation than during normal operation when analyzed
                     x
                                   n q "1C

at the 95 percent confidence level.  '    However, the magnitude of the low



NO  metal losses at Plant A is not enough to indicate any serious corrosion.
  A


Although for the Plant C tests of Table 6-10, the average coupon metal loss



was greater during normal operation than during low NO  operations, there
                 ""                      i      '        A


is no statistical difference betwen the normal firing and low NO  losses at
                                                                A


the 95 percent confidence level.9'16  For Plant D (Table 6-11) average



coupon metal loss was less during low NOV firing than during normal firing
                                        A-


when analyzed at the 95 percent confidence level.  '    For  Plant E (Table



6-12), average metal loss was the same for normal and low NOV firing.  The
                                                             A


metal losses reported in Tables 6-9, 6-10, 6-11, and.6.-12 provide data on



                               6-16

-------
                              Table 6-8

          COMPARISON OF AVERAGE BOILER EFFICIENCIES9'13'14

                BASELINE VERSUS LOW NO  MODE
                                     Boiler Efficiency
                                          Percent
                                 Baseline
               Low NO.
Plant A


Plant C


Plant D
89.1
89.4
89.4
89.0
89.5
89.7
                         6-17

-------
                  TABLE 6-9

PLANT A CORROSION TEST RESULTS FOR COUPONS EXPOSED
         30 DAYS AT 315-400°C (600-750°Fl
13
                                           Coupon Metal  Loss-
                                          Mi croraetres per year
                                          v.CMiTs/yr.)
Probe Location Coupon No.
1 1
2
3
4
Average
2 1
2
3
4
Average
3 1
2
3
4
Average
4 1
2
3
4
Average
5 1
2
3
4
Average
Test Average
Normal firing
49.2(1,94
53.5(2.11
46.2Q.82
33.9(1.33
45.70.80
44.50.75
55.4(2.18
43.80.73
30.9(1.22
43.6(1.72
45.9(1.81
41.2(1.62
26.2(1.03,
19.4(0.76,
33.2(1.3.
21.5(0.85]
33.8(1.33
35.5(1.40
28.5(1.12
29.80.17]
60.2(2.37]
53.3(2.10]
44.5(1.75)
52.6C2.07]
41.0(1.61]
Low NOV Firing
J\
) 68.2(2.68)
79.0(3.11)
] 79.6(3.13)
I 54.5(2.14)
) 70.3(2.77)
) 86.3(3.40)
I 52.1(2.05)
) 52.1(2.05)
5 52.1(2.05)
60.7(2.39)
I 84.4(3.32)
! 96.3(3.79)
i 100.5(3.96)
94.2(3.71)
) 93.9(3.70)
! 68.8(2.71)
75.9 2.99)
44.6 1.76)
44.6 1.76)
58.5 2.30)
63.0(2.48)
60.6(2.38)
61.8(2.43)
69.0(2.72)
                        b-18

-------
                   .  TABLE  6-10
PLANT C  CORROSION TEST RESULTS.FOR COUPONS.EXPOSED'
       .  300 HOURS,AT 3850CC725°Fr






Coupon Metal Loss -

Boiler
ft 1 - : .
No.
1



1





2


2




• -Probe-- 	
. •.* ... ...
No.
1
Qlorth. side I



2 -
(South Side)




3
(North, side)


4
(South Side}




Coupon

No. •
1
2
3 .
Pro5e
Average
1
2
3
Probe
Average
Test
Average
1
2
3
Probe
Average
IT.
2
3
Probe
Average
Test
Average
Micrometres
(Mls/yr)


Normal Firing I
1595 (62. 8)
813 C32,OJ
541 C21.3)

983 C30.71
384 (15.11
269 00.6}
335 03. 2)

324 (13.0)

656 (25.81
•*»*•*•,

—
.-"
—

^-,
per year

-ow NO., Firinq
	 !X 	 *•
	

—.

~-

	

-._.
1113 (43.8)
742 C29.2)
500 (.19.7)

785 (30. 9)
411 (16.2)
384 (15.1)
394 (.15.5)
396 (15.6)

591 (.23.3)
                      6-19

-------
                    "Table 6-11
                      !    f      ''',*.. ' ,""

PLANT D CORROSION TEST RESULTS FOR COUPONS EXPOSED
          30 DAYS AT 315-400°C (600-750°F)
14
                                    Coupon Metal Loss
                                   Micrometres per year
                                        (Mils/Yr)
Probe Location Coupon No.
1 1
2
3
4
Average
2 1
2
3
4
Average
3 1
2
3
4
Average
4 1
2
3
4
Average
5 1
2
3
4
Average
Test Average
Normal
108
102
55.5
24.1
73.3
71.9
46.6
28.1
20.1
41.7
56.7
58.2
36.9
26.7
44.6
64.8
67.3
49.3
32.9
53.6
88.0
73.4
37.1
13.3
53.0
53.3
Firing Low NO Firing
"X
(4.28
(4.02
(2.30
(0.951
(.2.89
25.2 (0.99)
30.7 (1.21)
,22.2 -(0.87)
) 25.8 (1.02)
1 26.0 (1.02)
(2.83) 47.1 (1.86)
(1.84) 72.6 (2.86)
(1.11
) 53.9 (2.12)
(0.79) 37.0 (1.46)
(1.64) 52.6 (2.07)
(2.23) 33.1 (1.30)
(2.29;
(1.45!
) 35.8 (1.41)
29.8 (1.17)
(1.05) 27.3 (1.08)
(1.76) 31.5 (1.24)
(2.55) 46.4 (1.83)
(2.65]
0-94]
CI.29J
(2.11)
45.0 (1.77)
47.6 ("1.87)
49.7 (1.96)
47.2 (1.86)
(3.47) 61.4 (2.42)
(2.89) 49.0 (1.93)
(1.46) 48.3 0.90)
(0.52) 31.6 (1.25)
(2.09) 47.6 (1.87)
C2.1Q) 41.0 (.1.61)
                 6-20

-------
                     TABLE 6-12

PLANT E CORROSION TEST RESULTS FOR COUPONS EXPOSED

          30 DAYS AT 315-400°C (600-750°F)
                           14
                                   Coupon Metal Loss
                                  Micrometres per year
                                       (Mils/Yr)
Probe Location Coupon No.
1 .11
-12
13
14
Average
2 n
. 12
13
14
Average
3 n
12
13
14
Average
4 11
12
13
14
Average
5 11
12
13
14
Average
Normal Firing
239
227
125
107
175
168
166
90.2
72.8
124
130
139
105
106
120
. 92.6
105
81.1
66.7
86.4
124
147
121
9.7.1
122
(9,41)
(8.94)
(4.92)
(4.21)
(6.89)
(6.61)
(6.541
(3.55)
(2.87)"
(4,88)
(5.12)
(5.471
(4.13)
(4.17)
(4.72)
(3.65)
(4.13).
(3.19)
C2.63)
C3.40I"
(4.88)
(5-791
(4.76)
(3.82)
(4.8Q)
Low NO
/\
109
96
100
220
131
143
168
166
141
155
190
152
112
122
144
120
128
124
79.
113
9.4.
106
77.
69.
86.
Firing
(4.29)
.3 (3.79)
(3.94)
(8.66)
(5.16)
(5.63)
(6.61)
(6.541
(5.55)
(6.10) .
(7.48)
(5.981
(4.411
(4.80)
(.5.671
(4.72)
(5.04)
(4.88)
2 (3.12)
C4.451
7 (3.73)
(4.17)
3 C3.04)
4 (2.731
7 C3.41).
    Test Average
126   (4.96)
126   (4.9.6).
                      6-21

-------
 comparative metal  loss,  but  are  not  quantitative  values  of boiler  tube



 wastage  (corrosion)  rates. *   *    After  analyzing  the foregoing data and



 other  internal  data,  Combustion  Engineering  says  that increased waterwall



 corrosion  rates would not be  a problem with  low NO  operation  of their
                                                  X


 modern pulverized  coal-fired  steam generators and CE is  willing to guarantee



 a NO   limit of  260 nanograms  per joule  (0.6  lb/106  Btu)  for new pulverized
    A


 coal-fired steam generators which burn Eastern coal and  210 nanograms per



 joule  (0.5 lb/106  Btu) for units which burn  lower rank Western coals.4'15



     Analysis of the  effect of low NO  operation  on steam superheat and
                                     X


 reheat temperatures during the Plant A tests shows  that  low NO  emission
                                                               /\


 levels can be achieved without steam superheat or reheat temperature



 reduction  when  the steam generator is operated in the range one-half to



 full load.  *   '    No slagging  problems were encountered during any of the



 tests which could  not be controlled with the normal sootblowing systems.9'13'14



     A flame ionization analyzer was used during  the Plant A, Plant D, and



 E tests to measure hydrocarbon emissions.  '    Hydrocarbon emission



 levels during these tests were below the lower limit of detection.13'14



     As previously discussed  and shown in Tables  6-7, 6-8, 6-9, 6-10,



 6-11, and  6-12, NOX emissions from Combustion Engineering modern design



 pulverized coal-fired steam generators can be controlled to low levels



without adverse side  effects.  During five test projects, the low NO
                                                                    X


 emitting steam generators were purposely operated under conditions



which would produce higher NO  emission levels.  ''    These conditions
                             /\


 involved operating with higher combustion gas oxygen content, no overfire



air, and/or improper burner and overfire air nozzle tilts.   Table 6-13



shows that much higher NOV levels were measured  when firing conditions
                         A.




                               6-22

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-------
deviated from the conditions required for low NOV control. ''
                                                X


Consequently, it is very important that NO  emissions be monitored
                                          A


continuously and accurately if real emission reduction is to be effected



by new source performance standards for NO  emissions from combustion.
                                          X


6.2.3  Foster Wheeler Energy Corporation and Riley Stoker Corporation
     Foster Wheeler reports their modern units are equipped for overfire,



interstage, and curtain air, (boundary air) and are designed to limit

                                                            3

NO  emissions by reducing combustion air to the firing zone.   Curtain
  X


air is used to prevent reduced air conditions at the boiler walls which


                                                             3
would cause accelerated tube wastage (corrosion) or slagging.   A Foster



Wheeler coal-fired steam generator was started up in December 1976 at a



Western power plant firing 22.6 megajoules per kilogram (9700 Btu/lb),


                        111?
0.9 percent sulfur coal.  '   This steam generator is subject to a State



of New Mexico regulation limiting NO  emissions to no more than 193
                                    X


nanograms per joule (0.45 lb/10  Btu).  The steam generator is still in



the shakedown phase of NOV emission control.    Foster Wheeler Corporation
                         X


is developing a low-turbulence dual throat coal burner with a double



annul us throat configuration for secondary air injection and individual



control of each annulus air supply.    The primary mechanisms by which



the new burner limits NO  emissions are control of turbulence and delayed
                        X                       '
mixing of fuel and air, thereby minimizing fuel NO  conversion.
                                                  /\
                                                               17
                                6-24

-------
     The special Foster Wheeler burner has been tested on three units;



two 265 MW opposed-fired units and one 75 MW front wall-fired unit.  All



of these units were modified existing units.  Modifications included



provision for overfire and boundary air.  NO  emissions were reduced about
                                            X


48 percent by the special burner and were reduced about 67 percent when
full overfire air was used in conjunction with the dual throat burner.
                                                                      18
NO  was reduced to about 300-350 ppm by the special burner with the overfire
  A

                    18
air 20 percent open.    CO concentrations were below 50 ppm and unburned



fly ash carbon was less than one percent.  When the overfire air was



opened 100 percent and the burners were adjusted for minimum NO , fly
                                                               f\


ash carbon increased to about 2.5 percent and slag began to accumulate


                                            18
after about 24 hours of full-load operation.    Slagging was substantially



alleviated, although not eliminated by the combined effect of the special


                                      18
burner and by the use of boundary air.    The furnaces were conservatively


                                                          ifi
sized because of the slagging characteristics of the coal.    No tube



wastage was evident from firing the good quality 26.77 megajoules per



kilogram (11,500 Btu/lb), 0.6 percent sulfur coal.18
                             6-25

-------
      Riley Stoker modern design units are equipped for underfire,


 overfire, and sidefire air, and emissions of NO  are limited by reducing
                                                A
                                   0

 combustion air in the firing zone.   These units are designed for about


 280 megajoules per second per square metre (1.5 x 106 Btu/hr/ft2) heat


 release rates as compared with heat release rates for older pulverized


 coal-fired units of 430 megajoules per second per square metre (2.25 x


 106 Btu/hr/ft2).2



      Riley Stoker Corporation is currently modifying the burners used
 in its  furnace design to reduce NO  emissions.
                                   X
                                               17
The new burners are
 designed to  control  mixing  of fuel  and air to  reduce thermal  and  fuel


 NOX.     With the  new burners  and  changes  in furnace  design, Riley


 Stoker  expects  to achieve low NOV emissions with  its new  boilers  without
                                A

 increased carbon  or  unburned  hydrocarbon  loss.


 6.2.4   Summary  of NO..  Control  Status
        11  -  - T ••    ~"  A           ^  -••""• •


     U.  S. Environmental Protection Agency test results show  that NO
                                                "                    X

 emissions  from  modern  Combustion  Engineering pulverized coal-fired


 steam generators  can be limited to  levels  less than  260 nanograms per


 joule (0.6 lb/10   Btu) without any  significant adverse side effects.


 Combustion Engineering will guarantee  its  new units  to meet this  limit


 for any type  of coal.4'15  For plants  firing coal which has little


 tendency to cause  slagging or tube wastage,  any of the four manufacturers


 is capable of furnishing coal-fired steam  generators which will limit


 NOX emissions to a level less than 210 nanograms per joule (0.5 lb/106
Btu).
     4,15
     There is not enough data or experience to indicate whether Babcock


and Wilcox, Foster Wheeler, or Riley Stoker modern pulverized coal-




                               6-26

-------
 fired  steam generators are capable of achieving low NO  emission levels
                                                      A


 without adverse  side effects when slagging or corrosive coals are fired.



 6.3  FEASIBILITY OF CONTINUOUS NO  CONTROL
                                 X


     Table 6-14  shows data on NO  emissions from tangentially fired
                                A


 boilers firing Western subbituminous coal.19  This Western power plant is



 required to control emissions to a level less than 300 nanograms per



 joule  (0.7 lb/10 Btu).  As shown by Table 6-14, emissions were sub-



 stantially below the foregoing level.  The plant is equipped to reduce or



 to increase N0x  emissions from the two tangentially fired steam generators



 by controlling the proportional quantities of overfire and secondary air.



 The plant reports that it is seldom necessary to change overfire air



 damper settings  since, as shown, NO  emission levels are characteristically
                                   A

    19
 low.    With constant overfire air damper settings, and by modulating



 secondary air control, NO  emission levels are the highest at full  load.
                         A


 N0x emissions decrease as the load is reduced.  Any necessary changes in



overfire air damper settings are made by plant engineers or management



personnel  and are not made by shift operators.  The data show that NO
                                                                     A


emissions  from subbituminous coal-fired steam generators are continuously



and consistently controlled to a level  less than 210 nanograms per joule



 (0.5 lb/106 Btu).
                                   6-27

-------
                             TABLE 6-14

      NOVEMBER 1977 NOV EMISSION CHARACTERISTICS OF TWO 350 MW
           TANGENTIALL? FIRED COAL FIRED STEAM GENERATORS
                  Nanograms per joule (lb/10  Btu),
                                                     19
Day

11-1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  2a
  29
  30
           Unit
24 Hour Average
Peak
170 (.40)
175 (.41)
190 (.44)
210 (.49)
105 (.25)
205 (.48)
215 (.50)
205 (.48)
230 (.53)
215 (.50)
210 (.49)
190 (.44)
185 (.43)
180 (.42)
190 (.44)
195 (.451
210 (.49)
260 (.60)
150 (.35)
170 (.39)
180 (.42)
140 (.33)
135 (.31)
140 (.32)
115 (.27)
140 (.32)
115 (.27)
130 (.30)
135 (.31)
140 (.32)
205 (.48)
230 C-53)
230 (.53)
290. (.67)
195 (.45)
295 (.69)
235 (.55)
240 (.56)
245 (.57)
270 (.63)
240 (.56)
220 (.51)
200 (.47)
200 (.46)"
215 (.50)
220 (.51)
235 (.55)
290 (.67)
170 (.39)
190 (.44)
205 (.48)
170 ,(.40)
140 (.33)
150 (.35)
150 (.35)
155 (.36)
120 (.28)
155 (.36)
160 (.37)
165 (.38)
           Uni;t 2
24 Hour Average
Peak
a
a
a
a
a
a
140" (.33) 150 (.35)
19,0 (.44) 220 (.51)"
180 (.42) 200 (.47)
155 (.36) 170 (.39)
175 (.41) 200 (.46)
180 (.42) 235 (.55)"
130 (.30) 185 (.43)
125 (.29) 190 (.44)
125 (.29) 140 (.32)
160 (.37) 215 (.50)
170 (,.4Q) 200 (.47.)
a
a
a
a
a
a
56 (.13) 120 (.28)
125 (.29) 195 (.45)
95 (.22) 130 (.30)
155 (.36) 170 (,39)
180 (.42) 200 (.47)
205 (".48) 225 (.52)
215 (.50
110 (.26
145 (.34
230 (.53)
180 (.42)
210 (.49)
200 (747) 205 (.48)
175 (741 ]
200 (.46)
170 (.40) - 230 (.53)
130 (".30) 175 (.41)
   No data - Unit out of service
                               6-28

-------
                REFERENCES FOR CHAPTER 6

 Standards Support  and Environmental  Impact Statement for
 Lignite  Fired Steam Generators, Emission Standards and Engineering
 Division, Office of Air Quality Planning and Standards, U. S.
 Environmental Protection Agency, Research Triangle Park, North
 Carolina, 1976.
 Memorandum, J. Copeland to G. B. Crane, Meeting with Riley Stoker
 Corporation, February 5, 1976, Emission Standards and Engineering
 Division, Office of Air Quality Planning and Standards, U.S.
 Environmental Protection Agency, Research Triangle Park, North
 Carolina, March 29, 1976.
 Memorandum, J. Copeland to G. B. Crane, Trip Report - Meeting
 with Foster Wheeler Energy Corporation of February 6, 1976,
 Emission Standards and Engineering Division, Office of Air
 Quality Planning and Standards, U. S. Environmental Protection
 Agency, Research Triangle Park, North Carolina, March 25, 1976.
 Memorandum, J. Copeland and G. B.  Crane to S. T. Cuffe, Trip
 Report - Meeting with Combustion Engineering, Incorporated,
 February 19, 1976, Emission Standards and Engineering Division,
 Office of Air Quality Planning and Standards, U. S. Environmental
 Protection Agency, Research Triangle Park, North Carolina, April,
 1976.
 Memorandum, J. Copeland and G. B.  Crane to S. T. Cuffe, Meeting
with Babcock and Wilcox Company,  February 18, 1976, Emission
 Standards and Engineering Division, Office of Air Quality Planning
 and Standards, U.  S.  Environmental  Protection Agency, Research
Triangle Park, North  Carolina, April  15,  1976.

                       67-29

-------
 6.   Subpart D, Part 60, Subchapter C, Chapter 1, Title 40, Code of
      Federal Regulations.
                                              i    .•..'.
 7.   Brackett, C.  E.  and J.  A.  Barsin, The Dual  Register Pulverized Coal
      Burner - A N0x Control  Device,  Babcock and  Wilcox Company,
      Barberton, Ohio,  February, 1976.
 8.   Campobenedetto,  E.  J.,  the Dual  Register Pulverized Coal  Burner -
      Field Test Results,  Presented at the Engineering Foundation
      Conference on Clean Combustion  of Coal,  Franklin Pierce College,
      Rindge, New Hampshire,  July 31  to August 5,  1977.
 9.    Crawford, A.  R.,  et al,  The Effect of Combustion Modification  on
      Pollutants and Equipment Performance of  Power  Generation  Equipment,
      Exxon Research and  Engineering,  Linden,  New  Jersey,  September,  1975.
 10.   Thompson,  R.  E.,  M.  W. McElroy,  and  R. C. Carr,  Effectiveness  of
      Gas Recirculation and Staged  Combustion  in Reducing  NO  on  a 560  MW
                                                           X
      Coal-Fired Boiler, Presented  at  the  Electric Power Research
      Institute  NOX  Control Technology  Seminar, San  Francisco,
     California, February, 1976.
11.  Telephone  conversation J. 0.  Copeland, Emission Standards and
     Engineering Division, U. S. Environmental Protection Agency,
     Research Triangle Park, North Carolina, with R.K. Thomson, Public Service
     Company of New Mexico, July 19, 1978.
12.  Steam Electric Plant Factors 1976, National  Coal Association,
     Washington, D. C., 1977.
13.  Program for Reduction of N0x from Tangential  Coal-Fired Boilers,
     Phase II, EPA-650/2-73-005-a, U.  S. Environmental Protection
     Agency, Research  Triangle Park,  North Carolina, June, 1975.

                                 6-30

-------
 14.   Overfire Air Technology for Tangentially Fired Utility Boilers Firing
      Western U.S.  Coal, EPA 600/7-77-117,  U.  S.  Environmental  Protection
      Agency, Research Triangle Park,  North Carolina, October 1977.
 15.   Private communication from H.  E.  Burbach,  Combustion Engineering,
      Incorporated,  to J.  0.  Cope!and,  Emission  Standards  and Engineering
      Division,  U.S.  Environmental  Protection  Agency, Research  Triangle
      Park,  North Carolina,  July 30, 1976.
 16.   Unpublished data,  Emission Standards  and Engineering Division,
      Office  of Air Quality  Planning and Standards,  U.S. Environmental
      Protection Agency, Research Triangle  Park, North Carolina, 1976.
 17.   N0x Control Review, Vol.  2, No. 4, EPA Industrial Environmental
      Research Laboratory, Research Triangle Park, North Carolina,
      Fall, 1977.
 18.  Vatsky, J., Attaining Low NOX Emissions by Combining Low Emission
     Burners and Off-Stoichiometric Firing, Foster Wheeler Energy
     Corporation,  Livingston, New Jersey,  November 1977.
19.  Unpublished data based on visit of Mr. Dan  Bivins,  Emission Standards
     and Engineering Division, U. S.  Environmental  Protection Agency,
     to Colstrip Station,  Montana Power Company,  January  17-19, 1978.
                                 6-31

-------

-------
                  7.   ENVIRONMENTAL IMPACT
 7.1   GENERAL
      As discussed in Chapter 6,  N0v emissions  from large pulverized
                                   X
 coal-fired steam generators  can  be controlled  without loss  of boiler
 efficiency or an increase in carbon monoxide or  particulate emissions.
 Hydrocarbon emissions from low NOV emitting sources  are  below the  limit
                                  A
 of  detection of  a flame  ionization analyzer.1  Although  it  is logical
 to  conclude that if  carbon monoxide emissions  are  not increased, poly-
 cyclic  organic matter emissions  are not increased, there  is  not enough
 data  to  prove this theory.
      More  effective  control  of NOX emissions from  large pulverized
 coal-fired  steam generators  using  the design and operating techniques
 discussed  in  Chapter  6 does  not adversely affect solid waste, water
 pollution,  noise, or  energy  environmental impact.
 7.2  AIR POLLUTION IMPACT
 7.2.1  Effect on Ambient Air Quality
     Table  7-1 shows emission source characteristics for various sized
model sources emitting NOX at full load capacity at the level of the
current NOX new source performance standard for pulverized coal-fired
steam generator of 300 nanograms  per joule ("0.7 lb/106 $tu].2'3  As
shown, air quality was measured for three different stack heights.

                               7-1

-------
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-------
Modeling techniques are described in Appendix F.
     Table 7-2 shows the impact of 25, 300, and 1000 megawatt sources
               3
on air quality.   The models assume that plants would be located in
flat or gently rolling terrain with a meteorological regime which is
                                            o
unfavorable to the dispersion of pollutants.   Downwash and retardation
effects were evaluated for the control building heights given in Table
    3
7-1.   The models assume that the plants are operated at full load
during an entire year.  The values reported are the maximum ground
level concentrations that were calculated for downwash, retardation, or
characteristic dispersion, whichever was the greatest.  Further information
on modeling techniques is given in Appendix F,  As shown by Table 7-2,
impact on air quality increases with plant size and decreasing stack
height.  In actual practice, the average annual concentrations would be
somewhat less, because plant load factors are usually less than 100
percent.
     As shown by Table 7-1, nitrogen oxides emissions were estimated
for NO and N02.  Nearly all of the nitrogen oxides emissions from
combustion are emitted as NO.   Assuming oxidation of the NO of Table 7-2
to N02 and excluding Case No. 7 which reflects the effect of severe
downwash yields a range of annual NO  concentrations (as NOo) of from
                                    s\                      £
less than 0.3 to less than 2 micrograms per cubic metre, compared to
the Primary and Secondary National Ambient Air Quality Standard for
nitrogen dioxide of 100 micrograms per cubic metre.
     The maximum ground level concentrations of Table 7-2 are for
sources emitting at the level of the current NOV new source performance
                                               A
                               7-3

-------
                         TABLE 7-2

        MAXIMUM  POLLUTANT  CONCENTRATIONS9  (yg/m3)
Averaging
Period
Annual








Case
1
2
3
4
5
6
7
8
9
NOC
0.7
0.2
<0.1
1.6
0.5
0.2
930
0.7
0.4
Distance
N02 (km)
<0.1 0.9
<0.1 3.0
<0.1 2.3
<0.1 6.4
<0.1 14.8
<0.1. 20.01
14 0.3b
<0.1 20.5
<0.1 23.3
 Concentrations have been pro-rated according to specific
 emission rates.

 First ring, downwash.

CNO oxidizes in atmosphere to N02.  However, it is not
 known what percentage of NO would be oxidized for the
 9 cases.
                            7-4

-------
                                      X
 standard of 300 nanograms per joule (0.7 lb/106 Btu).2  Reducing NO
 emissions to lower levels would proportionally reduce the NO  concen-
                                                             A
 trations shown in Table 7-2.
 7.2.2  Effect on Air Emissions
      Reducing N0x emissions from pulverized coal-fired steam generators
 from the level  of the current new source performance standard of 300
 nanograms per joule (0.7 lb/106 Btu)  to a level  of 260 ng/J  (0.6 lb/106
 Btu) would be equivalent to about a 14 percent reduction in  emissions. .
 A 29 percent reduction in emissions would result  from the  restriction  '
 of emissions to  a  level  of 210 nanograms  per joule (0.5  lb/106 Btu).
      Because it  takes  about 5 years to construct  a pulverized  coal-
 fired power  generation system,  the  air emission impact of  a  lower NO
                                                                    J\
 limit would  not  begin  for  at least  five years  after the  lower  limit
 became effective.  Thus,  the earliest  impact would  begin about  1982 or
 1983.  According  to power  industry estimates compiled  by the  Federal
 Power Commission, the total  capacity of fuel burning  power generation
 facilities will  increase by,about 189,400 megawatts during the 10 year
 period from the end of 1983  to the  end  of 1993.6'7  It is estimated
 about  161,000 megawatts (or  85 percent) of this new capacity will be
 pulverized coal-fired other  than lignite capacity.7  Based on the
foregoing estimate about 2.910 teragrams (3,210,000 short tons) of
additional NOX would be emitted in the 1993 year from new pulverized
coal (other than lignite) fired units  which are added during  the period
1983 through 1993,  assuming that emissions are limited to the leve]
7-5

-------
of the current new source performance standard of 3QO nanograms per



.joule (0.7 lb/106 Btu).  For control levels below the current standard,



nationwide NO  emission rates would also be increased by power industry
             A


expansion of coal-fired steam generating capacity.  However, the increase



would not be as great as with the current 300 nanogram per joule limit.



This is demonstrated in Table 7-3.  Beyond 1993 NOV control levels
                                                  A


below the current standard would continue to temper the impact of new



pulverized coal-fired steam generator activations on annual nationwide



NO  emissions.
  A


7.3  SOLID WASTE, WATER POLLUTION, NOISE, AND ENERGY IMPACT



     As discussed in Chapter 6, the viable techniques for reducing NOX



emissions from pulverized coal-fired steam generators involve changing



the way the fuel and air are introduced into the combustion chamber.



Since no additional waste materials are generated, more effective NOX



control does not increase or decrease the quantity of wastes and does



not change the character of the wastes.  The more effective NOX control



techniques discussed in Chapter 6 do not change the character or magnitude



of water or noise pollution.



     Although the test results discussed in Chapter 6 fail to show any



statistically significant difference in boiler efficiency for normal



firing as compared with low NO  'firing, it is likely fuel consumption
                              A


will be slightly less when NOV emissions are controlled to a lower
                             A


limit.  Thus, more effective NOV  control will probably have a slight
                               A


beneficial impact on energy consumption.



     As discussed in Chapter 6, NO  emissions can be controlled to



lower levels without increasing energy losses which would  be indicated
                               7-6

-------































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-------
by increased ash combustible content or increased CO emissions.  Although



the quantity of total excess air used during low NOX firing is much the



same as that used during normal firing, it is likely that for long term



boiler operation the total excess air used will be less for low NO
                                                                  /\


firing than for normal firing.  This is because operators will need to



control combustion air rates within narrower limits when firing in the



low NO  mode than when firing in the normal mode.  Lower excess air
      X


increases boiler efficiency.
                               7-8

-------
 REFERENCES  FOR  CHAPTER  7
 1.   Program for Reduction of-NOX from Tangential Coal-Fired Boilers, Phase II,
                                                                            i
     EPA 650/2-73-005-a, U. S. Environmental Protection Agency> Research
     Triangle Park, North. Carolina, June 1975.
 2.   Subpart D9  Part 60, Subchapter C, Chapter 1, Title 40, Code of Federal
     Regulations.
 3.   Unpublished Data, Source Receptor Analysis Branch., Office of Air Quality
     Planning and Standards, U. S. Environmental Protection Agency, Research
    Triangle Park., N. C.,, May 1975.
4.  Control Techniques for Nitrogen Oxides Emissions from Stationary Sources,
    AP-67,. U.  S. Environmental Protection Agency, Washington,  D.  C., March 1970.
5.  Part 50, Subchapter C, Chapter 1, Title 40, Code of Federal  Regulations.
6.  Summary of Electric Reliability Council Power Industry Expansion Projections
    1976-1995,  Federal  Power Commission, Washington, D.  C., 1976.
7.  Unpublished Data, Emission Standards and Engineering Division, Office of
    Air Quality Planning and Standards,  U.  S.  Environmental Protection  Agency,
    Research Triangle Park,  North Carolina, 1976.
                                    7-9

-------

-------
                CHAPTER 8.   ECONOMIC IMPACT ANALYSIS
8.1  INDUSTRY PROFILE



8.1.T  General Industry Background



     The market for large coal-fired boilers is dominated by the electric



utility industry.  As shown in the table below, over 88 percent of all



coal-fired units and over 98 percent of the rated megawatts installed



since 1960 have been electric utility power generation applications.
        Table 8-1..  COAL-FIRED UNITS INSTALLED, 1960-1976
                                                         1

•
# of units
installed
Installed megawatt
capacity
Electric
Utilities


404

159,051
%


88.8%

98.4%
Industry


51

2,519
%


11.2%

1.6%
Total


455

161,540
ct


100%

100%
     The electric utility industry itself has undergone some significant



market perturbations in recent years.  As Figure 8.1 shows, both energy



and peak load demand maintained a relatively stable growth rate of between



five and nine percent per year from 1961 through the early 1970's.  In 1973



a worldwide recession coupled with the Arab oil embargo caused a drop in



annual peak power demand for electricity in 1973.  Energy demand showed



virtually no growth in 1974, and only began to climb as the recession
                                 8-1

-------
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1960
                  .DECEMBER PEAK LOAD3
          ___.... ANNUAL ENERGY REQUIREMENTS
          "REPRESENTED BY THE SUM OF THE INDIVIDUAL PEAK LOADS OF THE REGIONAL COUNCIL'S

           REPORT TO THE FPC.
          I     I     i
              1962
1964
1966
1968


 YEAR
1970
                                                               1972
1974
                                                          1976
Figure 8-12. Percentage growth rate over previous year reported by major U.S. utility systems3.
                                              8-2

-------
 bottomed out in 1973.   Peak power demand for electricity rose  at  a  rate  of
 two to seven percent in 1975 and 1976, an increase over 1973 and  1974 but
 still  somewhat lower than  the 1960 to 1972 period.
      With the long lead times in plant construction  cycles  in  this  industry.
 the capital  programs tend  to  build a  great deal  of momentum.   It  is  not
 possible to  respond immediately  to changes in  the demand  for electric
 power.   Figure 8-2 shows how  reserves in the power industry soared  in 1973
 and 1974 to  a high of over 50 percent excess capacity over winter peak de-
 mand.   The summer  peak  margins would  be  somewhat lower.   Not only have the
 utilities suffered from this  overbuilt circumstance, but  a coincidental
 problem involves the precipitous  drop in  collective system capacity factor
 for the industry.   Figure  8-3 shows this  distinctive drop in capacity factors
 from 1973 to  1974.   The result of  these  phenomena are utilities with over-
 commited  capital programs  supported by systems generating less revenues
 due to  the lower plant  utilization.
     This problem  has lessened more recently due to increased demand for
 electric  power, but  peak winter reserve capacity is 46 percent and will
 continue  to be above 40 percent through the end of the decade.   As  a result,
 orders were very slack  for boilers since 1974.   In 1974, 69 coal-fired
 boilers with a rated capacity of 32,964 MWe were ordered; this  number
 shrank to 22  (10,774 MWe) in 1975 and 13 (6,312 MWe)  in  1976.   This  down-
ward trend appears  to have reversed itself in 1977.   Orders  for the  current
year are expected to total  at least 20, with capacity of approximately
          3
 13,000 MWe.   Market analysts are  confident of an increasingly strong market
as utilities  convert to  coal  or prepare to construct  new units  that  have
been delayed  due to sluggish demand for electric power.   However,  it will  be
at least several  years before  the dislocations  that occured  in  1973  and 1974
                                 8-3

-------
     LUMBERS FROM ALL FPC REGIONAL COUNCILS WERE AVERAGED TO OBTAIN ANNUAL
      REPRESENTATION.
         1962      1964      1966      1968      1970      1972      1974
Figure 8-24. Annual peak reserves as a percentage of total available capacity, 1961-19773.

                                     8-4

-------
   56


   55


   54


   53


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LU
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   51
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QC
o
   47
   46
   45
   44
   43
 r~rr
i    i    i     i    i     i    i    i    i
         CAPACITY FACTOR IS CALCULATED BY DIVIDING ANNUAL ENERGY PRODUCED BY TOTAL
          DEPENDABLE ENERGY CAPACITY.
   .42
    I960
1962       1964     1966      1968      1970

                             YEAR
                 1972
,1974
1976
            Figure 8-3^. Annual capacity factor for the major U.S. electric utilities3.
                                          8-5

-------
 are eliminated.   A return to a pre-recession level  of power  boiler  sales
 probably cannot  be expected for several  years.   Contributing to  this  cir-
 cumstance is the large backlog of boilers  already ordered  but delayed due
 to utility uncertainty over economic and regulatory conditions in the near
 future and passage of a comprehensive national  energy plan.
 8.1.2  Coal  As The Basic Fossil  Fuel  For Electric Generation
      The economic and_political  problems that have  surrounded oil and natural
 gas supplies over the past few years  have  brought on  a  strong interest in
 coal  as the  basic fuel  for electric  generation.   As was  indicated in  Chapter 3,
 the major fossil  fuel  boiler manufacturers anticipate no new orders for oil-
 and gas-fired power boilers.
      Figure  8-4  depicts  the  total  number of  coal-fired units  (over 25  MWe)
 installed (or scheduled  for  installation)  since  1960.  The steep change in
 1973  is indicative  of the  number  of units  being  delayed or cancelled  by the
 utilities.   There may  be some  additional delays  among the units scheduled
 out to  1978;  however,  the  recovery from  1973  is  apparent.  Generally,  coal
 demand  can be expected to  grow faster than the growth of primary electric
 demand  since  coal will most  likely replace a  sizeable portion of the genera-
 tion  that otherwise would  have been supplied  by oil or natural gas.   As
 discussed in  Chapter 3, it is uncertain  how much of this new generation
 capacity will be  from fossil fuels and how much will be nuclear.
      Figure 8-5 shows the average size of coal-fired units  installed since
 1963.  The slight downtrend in number of units installed shown in Figure 8-4
 is more than offset through the early 1970's  with consistently larger unit
sizes.  The average size of a coal-fired unit stabilized in the early
1970's.  To a limited extent this probably  is attributable  to technological  limita-
tions in the size of the generation units,  but more importantly the  economic
                                 8-6

-------
      aUNITS UNDER CONSTRUCTION BUT NOT YET IN COMMERCIAL OPERATION.

      bIN THIS AND SUBSEQUENT FIGURES, S-YEAR RUNNING AVERAGES ARE USED TO
       SMOOTH OUT VARIATIONS CAUSED BY RELATIVELY SMALL ANNUAL SAMPLE SIZES
14
1962
1964        1966       1968       1970       1972


                   INITIAL OPERATION YEAR
                                                               1974
1976
                                                                                    1978
  Figure 8-4^.  Aggregate annual number of installed coal-fired units over 25MW ona 5-year
  running average0.
                                             3-7

-------
1962
1964
1966
1974
1976
                              1968        1970        1972




                              INITIAL OPERATION YEAR




Figure 8-5. Average size of newly installed coal-fired units on a 5-year running average. 7
1978
                                                 8-8

-------
implications of relying on one unit for too large a percentage of a utility's
total generation need had started to limit.the size of newly installed units.
However, unit size is beginning to escalate, and a new generation of boilers
installed in the mid- and late 1980's will be somewhat larger than the
generation of boilers constructed in the 1970's.   The new boilers will
average about 554 MWe.
8.1.3  Competitors In The Coal-Fired Boiler Industry
     There are four competitors in the large (greater than 25 MWe) coal-fired
boiler market:  Combustion Engineering, Inc., Foster Wheeler Corporation,
Babcock and Wilcox Company, and the Riley Company.  Table 8-2 shows compara-
tive financial data for the four companies.  The data are aggregated and,
therefore, reflect all of the products each company produces, which vary
significantly.  Combustion Engineering, Inc., and Babcock and Wilcox Company
both participate as primary contractors in the nuclear power generation
business; all four companies supply a wide variety of products and materials
closely related to the power generation industry.
     Table 8-2 reflects the relative amounts of debt in the capital  structure
of each company as well as the relative return on sales.   These may offer
some insights on'each- company's ability to adjust to increased production
or design costs caused by environmental regulations.
                                    8-9

-------
  Table 8-2.  FINANCIAL DATA FOR FOSSIL-FIRED BOILER INDUSTRY8

                        (million $, 1976)

Assets
Equity
Long-Term Debt
Revenues
Net Income
R&D
Combustion
Engineering
1274.6
398.4
108.8
1830.9
54.2
28.8
Babcock &
Wilcox
1129.1
415.6
92.9
1691.8
53:1
27.4
Foster
Wheeler
476.1
. 128.5
45.3
1061.7
20.5
17.3
Riley
Company
151.0
33.1
14.1
210.2
4.9
2.5
     Table 8-3 shows that there is no significant disparity  between  the  four

manufacturers' reliance on the coal-fired boiler market.


Table 8-3.  RELIANCE ON COAL-FIRED BOILER MARKET FOR EACH SUPPLIER

                            (million $, 1976)
— 	 • 	
Million of
Dollars
Percent of
Total Revenue
• Revet
Combustion
Engineering
245.0
13%
lues From Coal-F-
Babcock &
Wilcox
230.6
14%
'red Boilers
Foster
Wheeler
197.7
19%
Riley
Company
42.9
20%
 Assumes  that the  equipment  price  for  coal-fired units  is $43/kW as quoted
 by FPC sources.   Installation  costs  are  not  included since boiler vendors
 generally do not do  site  installation  work.
      Figure 8-6 shows the percentage market  share  of  the coal-fired boiler

 market for each of these suppliers.  Figure  8-7 shows the  market  share  in

 total annual megawatts installed.
                                    8-10

-------
   60
 co 50

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                                    COMBUSTION ENGINEERING

                                    BABCOCK&WILCOX

                                    FOSTER WHEELER

                                    RILEY COMPANY
                                                             ACTUAL
                                                                 I
                                                                 I       _
                                                                 I PROJECTED3
                        .•••""		-^*-	.-—
                                                "*•••..
~t ...... "i   v.^.

 U - 1 - 1
                              aUNITS UNDER CONSTRUCTION BUT NOT YET IN COMMERCIAL OPERATION
                               1 - 1 -- 1 - 1 - 1 - 1 - 1     '     i      i     i
   1962        1964       1966       1968       1970       1972

                                        OPERATION YEAR
                                                    1974
1976
                                                                          1978
Figure 8-6^°. Annual installed megawatt capacity as a percentage of the total coal-fired market on
a 5-year running average.

                                                8-11

-------
   6000
   5000
   4000
   3000
<  2000
a
z
   1000
.COMBUSTION ENGINEERING
-BABCOCK&WILCOX
.FOSTER WHEELER
. RILEY COMPANY
                                            PROJECTED ACCORDING TO IN-PROCESS CONSTRUCTION
    1962       1964       1966       1968       1970       1972

                                    OPERATION YEAR
                                             1974       1976      1978
  Figure 8-71 1. Annual installed megawatt capacity for coal-fired units on a 5-year running average.
                                              8-12

-------
      By megawatt capacity installed, Combustion Engineering and Babcock
  and Wilcox are the clear market leaders, with approximately 40 percent of
  the total market each.  Foster Wheeler and the Riley Company sh.are the
  remaining 20 percent of the market.  Figure 8-8 shows the distribution of
 unit sizes by supplier for all  large coal-fired units installed since 1960.
 The Riley Company has clearly positioned itself in the small-size unit segment
 of the market with  one-third of its units in the 100-200 MWe  class and no
 Units  over 500 MWe.   The other  three manufacturers have relatively similar
 curves with  Foster  Wheeler,  slightly skewing toward 600-900 MWe units.
     There is no  indication  of  further  market segmentation either by  fuel
 type or geographic  location  of  the  plant.   In some cases  a particular supplier
 may have an  inordinate  number of units  in a  particular  area or  on a particular
 utility system.   Ths  is explained generally  by  the economies of plant dupli-
 cation (design, maintenance,  and operation factors)  as  well as  the possibility
 of more effective marketing  efforts  by  one supplier  in  a  particular area.
 The market is generally mature  enough so that thorough  economic and tech-
 nological  evaluation  of a bid may not indicate a clear  best choice, in
 which  case somewhat "softer" measures such as duplication of plant controls
 for easier operator training or more effective sales coverage may determine
 the winning bid.
     Historically the large coal-fired boiler industry appears to be a
 relatively stable and mature industry with perhaps two primary segments by
 unit size.  Among the large unit suppliers,  Combustion Engineering and Babcock &
Wilcox  hold similar market shares in both segments.  Foster Wheeler appears
quite capable of surviving in the large  unit segment though securing a notice-
ably smaller number of units. The  Riley Company,  on the other  hand, competes
primarily for smaller units  and  has  shown some recent gains in market  share for
                                      8-13

-------
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Figure 8-812.  Size distribution of coal-fired power plants installed  1960-1978 for 4 suppliers.
                                            8-14

-------
this size unit.  Even though the size of the total coal-fired boiler market
may be cyclical, there is no apparent reason to assume that there is going
to be a significant change in the relative market shares among these four
equipment suppliers in the foreseeable future.
                                 8-15

-------
8.2  COST OF CONTROL
     The degree to which the four major boiler manufacturers (Combustion
Engineering, Babcock and Wilcox, Foster Wheeler and the Riley Company can re-
duce NOx emissions below the current standard of performance (300 nanograms/
joule) is a function of their current boiler design, status of improved com-
bustors, and the type of coal burned.  In order to account for these factors,
                                                                                    n
three scenarios have been proposed to provide a range for possible impacts.
     The first scenario (Scenario I) under consideration is to postulate
that all of the major boiler manufacturers will be able to comply with the pro-
posed emission limits with their current modern design units or with insigni-
ficant modifications to current designs.  This scenario would imply that none of
the four manufacturer's boilers would undergo any change in capital or
operating costs.  This scenario is considered to be the most likely since
all manufacturers have indicated some optimism in reaching levels below
the current NSPS, although three manufacturers except Combustion Engineering
have expressed concern about the long-term effects on the boiler of operating at
such a low NOV level.  By definition this scenario has no economic impact.
             /\
     The second scenario assumes that two of the manufacturers who have
demonstrated the lowest NOX emission levels  (Combustion Engineering and
Babcock Wilcox) can meet the proposed emission limits on all coal types and that the
other manufacturers (Foster Wheeler and  the  Riley Company) need to modify cur-
rent designs when burning corrosive coal.  The assumption in this scenario  is
that the modifications to the current burners are relatively minor and can  be
accomplished without loss of market.  However, Foster Wheeler and the Riley
Company would  have  to invest in research and development to  improve their
burner designs.  The exact amount of this investment is unclear but an upper
bound approximation can be made.  Babcock and Wilcox estimated in 1976 that
                                      8-16

-------
the developmental costs for their burner system was about two million
        -] o
dollars.10  It has been assumed that this represents an extreme upper limit
on the cost of modifying the Foster Wheeler and Riley  Company systems to
achieve the proposed standard.
     The third scenario (Scenario III) chosen for analysis is the most extreme.
This scenario assumes that three manufacturers do not meet the proposed emission
limits with their current boilers.  In these circumstances the only alterna-
tives available to the manufacturers would be to use the tangential firing
system developed by Combustion Engineering or to develop a significantly
different combustion system.  Since this system is no longer covered by
patents, there is no legal or institutional barrier in adapting the Combus-
tion Engineering technology.  However, to use this technology the manufac-
turers would have to undergo major design and fabrication efforts and in
all probability would not be able to .compete effectively in the market until
designs were perfected.  While.there are potentially large costs associated
with this retooling operation, the magnitude of these costs cannot be
estimated.  As explained in Section 8.4, the potential loss of market share
for an extended period of time would far exceed any costs of retooling.
The economic implications of these design changes on industry structure will
be discussed in Section 8.4.
     In addition, there are some minor peripheral considerations such as opera-
tor training costs for operation with  less excess air; but considering that
this standard will apply only to new units which will  be incurring operating
training costs anyway, these incremental costs will  not be significant.
                                       8-17

-------
8.3  COSTS OF OTHER ENVIRONMENTAL CONTROLS
     The electric utility industry is subject to many environmental  regu-
lations other than those re.lated to air pollution.  The purpose of this
section is to summarize the expected capital and operating requirements
imposed on the industry as a whole and on a typical new utility boiler.
Unless otherwise noted all costs.are taken from "The Economic Impact of EPA's
Air and Water Regulations on the Electric Utility Industry."^
8.3.1  Environmental Control Costs for Typical New Installations
     As was shown in Figure 8-5 the newly installed coal-fired units are
currently averaging slightly over 500 megawatts.  Consistent with this, a
600 MWe coal-fired unit  was selected as the model new utility boiler.  This
plant is assumed to require chemical effluent treatment, a cooling tower, and
entrainment screens for water pollution control.
     Table 8-4 shows the estimated capital and operating cost for these
devices.
8.3.2  Total  Industry Environmental Control Costs
     Table 8-5 shows the total capital costs attributable to environmental
control costs in the electric utility industry for the period 1975-1985.  The
estimated cumulative total operating and maintenance costs associated with
this equipment between 1975 and  1985 is 6.1 billion dollars.  In addition
to these costs an estimated 1.0  billion dollars will.be required to provide
for  capacity  losses due to the operation of water  pollution control equipment.
                                       8-18

-------
            Table  8-4-   ENVIRONMENTAL CAPITAL COST FOR NEW PLANTS3

                                (1975 dollars)
Control Device
Chemical Effluent
Treatment
Mechanical Cooling
Tower
Entrainment Screens
Total
Cost/kW

1.52

5.77
4.08
11.37
Total Cost (106$)

.9

3.46
2.45
6.81
Annual O&M
(Mills/kl

.3

.2
.1
.6
Costs
Vh)






     Based on a new 600-MW coal-fired unit.
   Table 8-5.
               rnn™T            l975-1985 BY TYPE OF POLLUTION CONTROL
               EQUIPMENT (excluding equipment built for reasons other than
               compliance with federal regulations)
                                 Amount Built
                                 (million kWe)
               Capital Expenditures
              (billion 1975 dollars)
Mater Regulations

  Chemical Treatment

  Cooling Towers

  Entrainment Screens  &
    Cooling Towers
469.1

102.2


 13.4
$1.2

 2.6


 0.6
                                     8-19

-------
8.4  ECONOMIC IMPACT OF ALTERNATIVE EMISSION CONTROL SYSTEMS
8.4.1  Penetration of New Units             "
     Since the nature of the proposed emission control change involves
a potential process change, the economic impacts will tend to accrue in
proportion to the introduction of the affected units in the U.S. power •
generation base.  As a result the economic impacts will increase annually
as these units come on line and become an increasingly larger percentage.,
of the industry's generating capacity.  The long lead times between the
initial contracting for a large fossil-fired boiler and the initial
commercial operation create  a natural lag in measuring the economic and
technological impacts of standards which affect these units.  For example,
units which were designed subsequent to the original NOX standard in
1971 are only now coming on line.  Units affected by this revision of the
standard would not be coming into service until the early to mid-1980'.s.
Table 8-6 projects the percentage of total electrical power supplied by units
potentially affected by this standard.  The total additions of coal-fired
units were extrapolated out to 1990-
Making consistent assumptions about the growth in total generation capa-
bility over the same period, the table shows that by 1985 the units
affected by this standard will be approximately six percent of the total
generation capacity of the electric power industry. ' The actual  energy
generated by these units will be a larger percentage of the total energy
produced nationally since these units will tend to be more efficient than
older units and therefore will be put in service preferentially to older,
less efficient units.  This will give the newer units a higher capacity
                                     8-20

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       Table 8-6.   PENETRATION OF NEW COAL-FIRED UNITS  INTO U.S. GENERATING BASE
-




1982
1983
1984
1985
1986
1987
1988
1989
1990
— •• 	 T 	 ; • '•- 	 — 	
Projected3 i Annual
Total U.S.
Generating
Capacity
(Gigawatts)
700.1
735.2
772.1
810, 9b
851.6
894.4
939,3
986.4
1035.9
Coali
Fired
Additions
(Giqawatts)
11.6
12.2
12.4
12.9b
13.5
14.2
14.9
15.7
16.5
i
Cumulative
Coal -fired
Additions
from 1982
(•Gigawatts)^
11.6
23.8
36.2
49.1
62.6
76.8
91.7
107.4
123.9

Percent of
Total U.S.
Generating
Capacity
1.6
3.2 .
4.7
6.1
7.3
8.,6
9.8
10.9
12.0


Percent of
Total U.S.
Energy
Generation
2.1
4.2
6.1
7.9
' 9.5
11.2
12.7
14.2
15.6
 Taken from Tables 3-6 and Footnote 15

 Extrapolated from Tables 3-6 and Footnote 15 at constant growth factor.
 References the same as shown on Chapter 3 tables.

cFrom the projections in Table 3-6 in Chapter III, approximately
 4.96 percent of this capacity will  be to replace retiring units.
 The remainder goes toward net system expansion.
                                       -8-21

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factor than the system average.   We have assumed a 65 percent capacity
factor for a new base load coal-fired plant (5694 hours/year) compared
to overall system capacity factors of 50 percent.  Using a rough calcu-
lation for the first few years,  this factor would increase the impact
of this penetration by approximately 30 percent  (5Q percent^'  This
explains the last column in Table 8-6.  These data indicate the considerable
lag in economic impact on this industry of a standard which only affects
new units as they are put into commercial service.
8.4.2  Scenario I Impacts
     The  economic impacts from Scenario I are by definition  negligible.
This scenario  presumes that all four manufacturers are able  to meet the
lower  NOX standard  on large coal-fired  boilers  with  their existing designs
incorporating  staged combustion techniques and  operated at  controlled
levels of excess  air.  There  are  no  design changes or efficiency losses
associated with  this scenario and consequently  there are  no direct costs
of control.  There  are some minor peripheral  considerations such as operator
training  costs for  operation  with less  excess air, but  considering that
this standard  will  apply only to  new units which will be  incurring operating
 training  costs anyway, these  incremental  costs  will  not be  significant.
     Test data on several units  (see  Chapter 6)  indicate  that this scenario
Is the most likely  to occur.                  I
 8.4.3  Scenario II  Impacts
      This scenario presumes all  four manufacturers  are  able to meet  control
 limits when firing coal  with little potential  for causing tube wastage,
 but Foster Wheeler and Riley will have to develop a  low NOX burner'for use
                                     8-22

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when firing coal with a high potential for causing tube wastage.   Possible



economic impacts resulting from this situation are the extra research and



development costs associated with designing a low NO  burner.
                                                    J\


     Research and development costs for designing a new burner are not



expected to be more than two million dollars (see Section S.2).  For Foster



Wheeler, this is 11.5 percent of their research and development budget



for 1976 and less than 0.2 percent of total sales (see Section 8.1, Table



8-2).  It is reasonable to believe that this cost would not have a signifi-



cant impact on Foster Wheeler's financial situation, for if such research



and development efforts were recovered in the first year the burner is put



into operation, the increase in price would be less than 1.0 percent.



     The situation poses a somewhat different and possibly significant pro-



blem to the Riley Company.  Riley's research and development budget for



1976 was 2.5 million dollars, and is projected to be 1.8 million dollars for



1977.  The reason for the decrease is a slowdown on coal gasification



research.  Increased costs of two million dollars would more than double



the research and development budget in 1977.  While this may be viewed as



a serious problem, there are several mitigating circumstances.  Should the



1977 research and development budget escalate to 3.8 million dollars,



research and development expenditures as a percent of total sales (projected



to be 242 million dollars in 1977) would be 1.6 percent.  Overall, industry



research and development expenditures as a percent of total sales is  a.lso 1.6



percent.  Another mitigating factor is the current research Riley is
conducting, in low NOV burner design for its Turbofurnace.   These
new
burners are designed to control mixing of fuel and air to reduce thermal



and fuel N0x.  It is quite possible that Riley would not need to spend
                                 8-23

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the full two minion dollars specified in o.rder to develop a burner that
can meet the proposed standard.  Foster Wheeler is also currently engaged
in research to develop a new low NO  burner, so there is a possibility that
                                   X
both companies may not.have to spend a full  two million dollars  to perfect
a new, low NO  burner.  With or without this possibility, the economic
             X
impact of increased research and development expenditures by both Foster
Wheeler and Riley should not be significant.
8.4.4  Scenario III Impacts
     The most serious economic impact that could evolve from this standard
involves the inability of one or more suppliers to provide a unit which will
meet the standard even with the modifications discussed in Scenario II.  ,
As has been noted all suppliers appear to be able to meet' the proposed
lower standard.  However, if the results of the other suppliers' new units
(designed since the 1971 standard) are such that they cannot or will not
guarantee the lower standard, the  impacts on the marketplace could be
significant.
      If a supplier whose current design  did not meet the standard chose
to adopt a  tangentially-fired  design  he  would  face two obstacles:
      1.   The length  of time and cost associated with
          redesign  effort;
      2.    Reluctance  on the part of the  electric  power  industry
           to  buy  the  design from a supplier who had  not  been
           offering  it previously.
      On the first point, without anticipating  the  need  to  make  such a  major
 redesign  effort,  a  supplier effectively  is  likely  to be  "out of the market"

-------
for the period of the  redesign effort.  The potential damages that could
accrue from producing and selling.a unit that failed to meet the standard
could be very high if they involve plant shutdowns or major reductions in
efficiency by dropping preheat temperatures.  If a supplier chose not to
take these risks and instead redesign to a tangentially-fired unit, he
would incur not only the costs of the redesign and retooling,, but for the
period of time the redesign takes, he would be trying to secure orders
without the support offered by "typical" drawings and other technical
documentation for the design he was offering.  Similarly, performance and
construction guarantees for the new design for the most part would be
unsubstantiated.  With the relatively long lead times between the order
date and the shipment date for a large coal-fired boiler it is not likely
that even a six-month redesign effort would create a period when a supplier
could not meet a shipment date as a result of the redesign effort.  Although
design and manufacturing drawings may be later in the manufacturing process
for some parts of the units, the parts would probably still be shipped in
time to meet any normal  construction schedules.   Several  factors could
complicate this; for example,  the power generation business is cyclical.
As shown in Section 8.1  the industry has been in a sales "trough" since 1974,
and in the past year has just  begun to climb slowly out of it.   If
a sudden rush in orders  (typical  in this business) .occurs at the same time
as a major redesign effort,  a  supplier may have  to forego bids that are
decided on a short-cycle installation basis.
     It is important to  distinguish between the  type of dislocation being
produced here and the design changes that occur  as the normal  evolution
of the product.  In the  latter case the design changes tend to be logical
extrapolations of previous designs which are introduced in a carefully
                               8-25

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timed and coordinated fashion.   The redesign involved in going  from
opposed wall firing to tangential  firing is not only more radical  but
also could not be timed for the most opportune entry into the market.
     The other obstacle involved with such a redesign effort concerns
buyer behavior.  As Table 8-6 showed,  there are only 20  to  25 new
coal-fired units being added per year out to the early 1980's.   Since many
of these are multiple-unit purchases there may be as few as 10-15 discrete
purchase decisions per year.  (This assumes a noncyclical market and sales
of units in a year occurring at the same approximate pace that  units are
put in service.)  Considering that the "average" utility might  not be in the
market more frequently than every few years, these purchase decisions are
not only few in number but also likely to vary considerably in  their decision
criteria.  There are, of course, factors which tend to make these decisions
more homogenous, such as the broad regulation  in the industry and all-company
competition in the same capital market environment.  However,  it is still
very difficult to depict a typical purchase decision for a large coal-fired
boiler.  Different utility companies will have different criteria and method-
ology for making the decision, and there are so few data points (as a result
of the low  number of transactions) that it  is  impossible to do  statistical
analysis.   These characteristics of the market place preclude  the use of
elasticity  considerations in evaluating such a highly differentiated product.
     In conclusion, it is difficult if not  impossible to anticipate the market
reaction to one of the non-tangential manufacturers to  convert over to
tangential  design.  Some utilities may perceive this as a  harmless change;
others may  penalize such an offering  for the likelihood of  "learning curve"
problems often associated with radical redesign efforts.   Even though
this difficulty exists it is possible to assess some of the  impacts if
                                 8-26

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  they were to occur.   Table 8-7  shows that a change in sales'billed
  equivalent to one sale involving two 600 megawatt coal-fired  units  would
  greatly impact any of these companies'  share of the coal-fired  market.
  The  fact that in  the  future the  coal-fired market is likely to  be signi-
  ficantly larger relative  to other  fossil-fuel  fired markets may tend  to
  overstate these numbers;  but at  the  same time  this  large coal-fired market
  proportionally  increases  the likelihood  of occurrence of an order being
  placed  as  a  result of  these design considerations.
 Table 8-7.
                                         ONE TWO-UNIT (600 MW) ORDER ON
	 — 	 : 	 : 	
Company
Combustion
Engineering
percent or Annual Coal-
Fired Megawatts^
i
23% .
i
Babcock & Wilcox
Foster Wheeler

The Riley
Company
25%
88%


150%
Percent of Annual
Revenues"
•
4.2%

4.7%
6.9%
V

31.9%c
Figure 8-7)"^ rUnn1n9 &Vera9e °f coal-fl>ed installation in 1978 (see
                                                    the Rfiey
     The comparison of the revenues from one such order to the total
revenues of the company reflects both the size and the diversity of the
four suppliers.  The Riley Company is clearly the most vulnerable by this
measure; however, this impact is mitigated somewhat by the fact that
                                  8-27

-------
Riley to some extent is segmented away from the other suppliers and there-

                             •

fore may be less likely to lose any given order as a result of redesign



considerations..



      By way of summary, it is difficult to predict the possible market



share effects of one or all three non-tangentially-fired suppliers converting



their combustion system design.  It is not likely that purchasers would



devalue such a bid on the basis of capital cost or efficiency since these



are not likely to change significantly; however,  they may penalize such



bids for some period of time on the basis-of possible forced outage-rate



impacts or construction delays associated with such radical redesign



efforts.  If such is the case  and market  shares are indeed shifted as a



result of such  redesign, the impacts  could be very severe, especially on



the two smaller,less diversified companies.



8.4.5  Modified/Reconstructed Facilities



      The proposed standard is not to be applied on a retrofit basis.



Only neti units which commenced construction on or after the date of proposal



of these regulations will be affected.  It is not anticipated that any



existing units will meet the requirements of being classified as modified or



reconstructed units as delineated in  Chapter 5 of this standard support   j
                                                                          t
                                                                          \

document.  As a result there will be  no economic  impact on modified or    |
                                                                          |

reconstructed facilities.                    _,




 8.5  POTENTIAL SOCIOECONOMIC AND INFLATIONARY IMPACT



 8.5.1  Inflationary Considerations



      All three scenarios do not have the potential  for having any d'irect



 inflationary impacts.  Even under the most radical  scenario,  that of  all
                                  8-28

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manufacturers being forced to use tangential design, the costs would
only be in redesign and retooling efforts.  These costs, when passed
along over a long period of time (attributable to the slow penetration of
units affected by this'standard) should prove to be minimal and non-infla-
tionary.
8.5.2  Energy Considerations                                  	
     None of the three scenarios discussed entail any efficiency losses.
Consequently, the impact of the proposed  standard on energy consumption
would be insignificant.I          .
8.5.3  Secondary Socioeconomic  Impact's
     Clearly, Scenarios I and II could not involve any  significant  second
order impacts to society.  The  only  concern over adverse socioeconomic
impacts centers on  Scenario III.  The differential impact on  the four key
suppliers in this industry could have significant impacts on  the industry.
structure.  The industry by its nature is already highly concentrated.
Any circumstance that might tend to  concentrate  it'further may  have serious
long-term impacts.
8.6  SUMMARY
     There will be  no additional cost of compliance under the most  likely
scenario since compliance is achieved by changing the, structural configura-
tion of the boilers, not by adding  control equipment.   Therefore, with no
additional outlays,  there will  be no inflationary pressures generated nor
will there be any consumer cost  increases.  The  small business section
will suffer.' no deleterious  effects  since  none of  the four companies
involved are in that category.   Energy requirements will not  increase.
If anything,  with the lowered ratio  of excess air, there may be  a very
slight  decrease.
                               8-29

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                    REFERENCES FOR CHAPTER 8

1.   Experience  sheets, Foster Wheeler Corp., Babcock and Wilcox Co.,
The Riley Company, Combustion Engineering, Inc., Emissions Standards  and
                     t
Engineering Division, Office of Air Quality Planning and Standards,  U.S.
Environemntal Protection Agency, Research Triangle Park, North Carolina,
1976.
2.   Federal Power Commission, Electric Power Statistics, December,  1974,
Table 4, page 14, and Edison Electrical Institute, Annual Electric Power
Survey.
3.   Kidder Peabody Co., A Status Report  on Electric Utility Generating
Equipment. Fossil Boilers as of December  31,  1976, March, 1977.
4.   FPC, Op_. cit., Table 15, page 14.  December 13 and August 31, numbers
were averaged to  get annual  representation.
5.   Ibid.  Table 14 and Table 15, page 14.   Capacity factor is calculated
by  dividing dependable  capacity  (converted  to kWh) by annual energy.
6.   Op. cit.,  Experience Sheets.
7.   Ibid.
8.   Security  Exchange  Commission, Form 10K,  Foster Wheeler Corp., Babcock
and Wilcox  Co.,  The Riley Company, Combustion  Engineering, Inc., 1976.
9.    Ibid.
 10.  Ibid.
 11.  Ibid.
 12.  Ibid.
 13.  Meeting Notes,  Meeting  with Babcock  and  Wilcox Co.,  Barberton,  Ohio,
 October 1976.
                                  8-30

-------
 14.   "The Economic Impact of EPA's Air and Water Regulations on the
 Electric Utility Industry," Temple, Barker and Sloane, Inc., prepared for
 EPA under Contract No. 68-01-2803, March, 1976.
 15.   Unpublished calculations or data, Emission Standards and Engineering
 Division, Office of Air Quality Planning and Standards, U.S. Environmental
 Protection Agency,  Research Triangle Park, North Carolina.
 16.  FPC, op cit.
17.  "NOX Control  Review,"  United States  Environmental  Protection Agency,
Fall,  1977,  page 5.
                                8-31

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              9.  RATIONALE FOR THE  PROPOSED STANDARD





     This Background  Information document supports proposed nitrogen



oxides  (NO  ) emission  limits for the combustion of pulverized coal
          A


(except lignite and coal refuse) in new electric utility steam



generating units with  heat input rates greater than 73 MW  (250 million



Btu per hr).  The proposed NOV emission limits for units which burn
                             A


lignite,1?2'3'4 coal refuse,,5'6'7 liquid and gaseous fuels,8'9'10



shale oil, and  fuels  derived from coal11'12'1'3'14'1^^ based on



other studies, as referenced, and are not discussed in this document.



Additional information may be found in the preamble and regulation for



Subpart Da in the Federal Register.



     Also, all information EPA used in developing the proposed regulation



may be found in the Subpart Da docket (number OAQPS-78-1) at the EPA



Central Docket Section (A-130), Room 2903B, Waterside Mall, 401 M Street



S. W., Washington, D.  C.  20460.





9.1  SELECTION OF SOURCE FOR CONTROL



     Electric utility steam generating units contribute significantly to



national emission levels of nitrogen oxides (NO ).   In 1976 total  nation-
                                               A


wide emissions of NOX amounted to about 23.0 teragrams (25.5 million tons);



electric utility units acounted for 29 percent of this, or 6.67 teragrams



(7.35 million tons).   The total capacity of all U.  S.  units was about





                                    9-1

-------
 340 gigawatts in 1975 and is expected to rise to 470 gigawatts  by 1985,
 representing a capacity increase of 38 percent in only 10 years.   About.
 250 new units are expected to commence operation during this  period.
      Due to high emission levels and a strong growth rate, the  electric
 utility industry will  continue to be a major source  of nationwide NO   emissions
                                                                    X
 in the future, second only 'to mobile source  emissions.   Consequently,  EPA
 believes there is an  important i
 utility-steam generating units.
believes there is an important need to control N0v emissions from electric
                                                 X
 9.2   SELECTION  OF  POLLUTANTS AND AFFECTED  FACILITIES
      Electric utility  units emit three major pollutants  into the atmosphere:
 sulfur dioxide, particulates, and  NOV.  Regulations have been developed for
                                    /\
 sulfur dioxide  and particulates, and these are supported in separate
 Background  Information documents.   '    Other air pollutants, including
 carbon monoxide, and hydrocarbons  are also emitted by electric utility
 units.  The quantities of these emitted into the atmosphere, however,
 are small.
      The affected facility to which the proposed emission limits would
 apply would be defined as any steam generating unit which:
          is located in an electric utility power plant;
          is capable of combusting greater than 73 MW (250 million
      Btu/hr) of fossil  fuel either alone or in combination with other
      fuels; and
          commenced construction or modification on or after the date
      of proposal of these emission limits in the FEDERAL REGISTER.
     The proposed regulations would only cover steam generating units
which are located in electric utility power plants since study of
emission controls for industrial units  would require a different economic
                                    9-2

-------
analysis.  Also, different control technology may be needed for industrial
units.   Industrial units of more than 73 MU  (25C million Btu/hr) heat input
are presently covered under Subpart D for fossil-fuel-fired steam generators,
and studies are in progress to develop revised emission limits for these types
of units.
     Although the proposed emission limits are primarily concerned with the
combustion of fossil fuels, the regulations would also cover new units which
burn other fuels either alone or in combination with fossil fuels.  A pro-
ration equation is included in the regulation which would simplify the
determination of an appropriate emission limit when a combination of fuels
is burned simultaneously in the same unit.
9.3  SELECTION OF THE BEST SYSTEM OF CONTINUOUS EMISSION REDUCTION
     CONSIDERING COSTS
     NOX emissions are controlled by modifying the way the fuel  is
combusted in the boiler.  EPA believes that the best system for  control
of NOX emissions from electric utility steam generating units which burn
pulverized coal is a combination of staged combustion, low excess air,
and reduced heat release rate.  These combustion modification techniques
are basically the same as those needed to achieve the original NO  emission
                                                                 A
limits for steam generators under Subpart D.  The costs associated with
greater implementation of these combustion modification techniques, as
needed to comply with the revised NOV emission limits under Subpart Da,
                                    'X
would be minimal.  Another emission control technique, flue gas  treatment,
has not yet been demonstrated effective for reducing NO  emissions from
                                                       X         '
coal-fired units.
                                     9-3

-------
     There are  several  potential side effects associated with operation
 of a unit at  NO  levels  as  low  as the proposed limits.  These are:  boiler
                s\
 tube wastage; slagging;  increased emissions of particulates, carbon monoxide,
 polycyclic organic matter,  and  other hydrocarbons; boiler efficiency losses;
 carbon loss in  the ash;  low steam temperatures; and operating hazards
 (including boiler explosions).  EPA has evaluated these side effects and
 believes that none would be a problem during operation of a boiler at
 the NO  levels  required  by  the  proposed emission limits.  Concern over
      A
 several of the  potential side effects, however, including tube wastage,
 slagging, increased emissions of polycyclic organic matter and particulates,
 and possible operating hazards  has been expressed by industry.  These concerns
 are responded to  below.
     Tube wastage (or corrosion) is the deterioration of boiler tube
 surfaces due to the corrosive effects of ash in the presence of a reducing
 atmosphere.   (A reducing atmosphere often accompanies low NO  operation).  The
                                                            J\
 severity of tube wastage is believed to vary with several  factors, but
 especially with the quality of  the coal burned.  For example,  high sulfur
 Eastern coals are believed  to cause more of a tube wastage problem than
 low sulfur Western coals.   Serious tube wastage can shorten the life of a
 boiler and result in expensive  repairs.
     Concern over tube wastage  is reflected in a statement made by one of
 the four major boiler manufacturers, Combustion Engineering, that it would
 guarantee its new units to meet an NO  limit of 210 ng/J (0.5 Ib/million Btu)
                                     A.
when burning low sulfur, low rank Western coals, but only  260 ng/J when
 burning the higher sulfur Eastern bituminous coals (see Appendix C).   The
other boiler manufacturers and several  electric utilities  have also
expressed concern over the potential for tube wastage with high sulfur
Eastern coals.

                                     9-4

-------
      Corrosion test results are available for five of the six units EPA
 tested in support of the proposed emission limits.  These tests involved
 the measurement of metal loss from test coupons inserted into the boiler.
 The results indicate that corrosion was not a serious problem for at
 least four of the units during the testing.  These were all  tangentially-
 fired boilers manufactured by Combustion Engineering.   It should be
 noted,  however,  that coupon corrosion tests indicate only relative
 corrosion rates  in selected areas  of a boiler and do not demonstrate what
 the long-term effects  of corrosion would be on the life of a unit.
      EPA believes that new units which would be designed to  comply with
 the proposed N0x  emission limits would not experience  serious  tube wastage
 for the following reasons:
           Coupon  corrosion  tests indicate  that tube  wastage  is
      not  significantly accelerated during  low NO  operation  of
      modern  Combustion  Engineering boilers.      x.
           Combustion Engineering has  stated  that its modern  units
      would be  capable  of achieving, without  adverse  long-term side
      effects,  a 260 ng/J  (0.60 Ib/million  Btu)  emission  limit when
      burning  Eastern bituminous coals  and  210  ng/J (0.50  Ib/million
      Btu)  when burning  lower rank  Western  coals  and  lignite.   These
      are  essentially the  same limits  as  those  proposed by EPA.
           Foster  Wheeler  and Babcock  & Wilcox  have executed
     contracts to build units which will be required to comply
     with  the State of  New Mexico's N0v  emission limit of 190 nq/J
      (0.45 Ib/million Btu).           x
          _Babcock & Wilcox has designed  a new burner which will
     permit a furnace to  be maintained in an oxidizing environment,
     thus, minimizing the potential for  furnace wall/corrosion when
     high sulfur bituminous coal  is burned.
        _  Foster Wheeler and Riley Stoker are developing new  burners
     which may have the same advantage as the new Babcock & Wilcox
     burner.  Also, Foster Wheeler incorporates "boundary air"  in
     its modern units to minimize reducing conditions near the boiler
     wall where tube wastage occurs.
     Unmanageable slagging was not  reported during any of the EPA emission
tests conducted in support of the proposed limits.   Based on  the boiler
                                      9-5

-------
manufacturers' experience with high slagging coals, EPA believes that



modern units which are designed with ample furnace volumes would



minimize slagging while complying with the proposed emission limits.



     Polycyclic organic matter (POM) is a concern because some types of



POM have been identified as possible carcinogens.  EPA has POM



emission data from only one unit.  This is an old-style unit, however,



and its emissions are probably not representative of emissions from



modern-design units.  It is reasonable to believe that POM emissions



should not increase on modern units because POM generation is closely



related to incomplete combustion, and poor combustion was not apparent



during the EPA tests.  This is evidenced by CO emission levels which



were generally the same during normal and low NO  operation.  Also,
                                                X


electric utility power plants contribute very little (less than one percent)



to total nationwide emission levels of POM.  Thus, EPA does not believe



that POM emission increases will be significant as a result of these



revised regulations.



     During EPA tests of modern units, particulate emission levels were



variable.  However, no significant increases in particulate levels were



detected which could be directly attributed to boiler operation at low



NOV  levels.   Consequently, EPA does not believe that particulate



emissions would  increase as a result of low NO  operation.
                                              A


     There was no indication during EPA testing that operation of a



boiler at the NO  levels required by the proposed limits could cause
                A


boiler operating hazards.  During discussions with the boiler manufacturers



in 1976, EPA asked if more effective NO  control would increase safety
                                       A


hazards.  The three largest manufacturers indicated that they were not
                                      9-6

-------
worried about safety hazards at reduced NO  levels.  Based on EPA field
  .                                        /\


experience and discussions with the boiler manufacturers, EPA does not



believe that NO  control would result in serious safety hazards.
               X




9.4  SELECTION OF THE FORMAT OF THE PROPOSED STANDARD



     The Clean Air Act Amendments of 1977 require EPA to establish both



emission limits and percent reductions in uncontrolled emission levels



for new steam generators which burn fossil fuels.  EPA has decided to



apply these requirements to the combustion of all fuels so as to simplify



enforcement and to effect greater environmental benefits.



     The proposed emission limits are expressed as mass per unit heat



input (nanograms per joule, or pounds per million Btu).  In 1971 when



emission limits for steam generators were promulgated under Subpart D,



EPA determined that units of mass per unit heat input were the most



practical of several options.  EPA believes that it is still practical



to express the proposed revised emission limits for steam generators in



terms of these units.



     It is impossible to specify a rational percent reduction in uncontrolled



NO  emission levels because there is no direct relationship between NO
  *                                                                   x


emissions with and without control.  Furthermore, since NO  control with
                                                          X


combustion modification techniques occurs in the furnace at the instant



that NO  is formed, there is no way to measure uncontrolled NO  emission
       "                                                      X


levels prior to combustion.  However, to comply with the requirements



of the Act, EPA has defined representative uncontrolled emission levels



for solid, liquid, and gaseous fuels, and a percent reduction for each



fuel has been specified.  The defined uncontrolled emission levels are
based on worst-case emission rates, according to published emission factors.
                                                                            18
                                        9-7

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     The proposed percent emission reduction requirements are as follows:

          A 25 percent emission reduction would be required for
     gaseous fuels, based on an uncontrolled emission rate
     defined as 290 ng/J (0.67 1 fa/million Btu).

          A 30 percent emission reduction would be required for
     liquid fuels, based on an uncontrolled emission rate
     defined as 310 ng/J (0.72 Ib/million Btu).

       •   A 65 percent emission reduction would be required for
     solid fuels, based on an uncontrolled emission rate defined
     as 990 ng/J (2.3 To/million Btu).

If a unit is in compliance with the appropriate NO  emission limit, then
                                                  X
it will automatically satisfy the percent emission reduction requirement.

Thus, in the case of NO  emissions, the percent reduction is not controlling,
                       A
and compliance testing for the emission limitation will automatically satisfy

all compliance testing requirements.


9.5  SELECTION OF EMISSION LIMITS

     NO  emission tests were performed on six modern pulverized coal-fired
       A
electric utility steam generating units.  Four of these units were new

Combustion Engineering designs, one was a Combustion Engineering unit

which had been retrofitted with overfire air, and one was a Babcock & Hilcox

unit which had been retrofitted with low-emission (dual register) burners.

During these tests NO  emissions were consistently below 260 ng/J
                     A
(0.60 Ib/million Btu) and commonly below 210 ng/J (0.50 Ib/million Btu).

However, due to the potential for tube wastage associated with low NOX

operation, EPA has concluded that it would not be reasonable to establish

an NO  emission limit for pulverized coal-fired units at 210 ng/J for
     A
al1 types of coal.

     As mentioned in section 9.3, tube wastage is of major concern,

expecially when Eastern coals are burned.  EPA has concluded from field
                                   9-8

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testing results, discussions with industry, and the advice of our research
laboratories that an NOV emission limit of 260 ng/J would be appropriate
                       X
for new units which burn Eastern coals.  At this emission level, EPA
believes that tube wastage would not be accelerated as a result of the
application of combustion modification techniques.
     Tube wastage does not appear to be a problem at emission levels as
low as 210 ng/J when low sulfur, low rank Western coals are burned.
Consequently, EPA has proposed an emission limit of 210 ng/J for new
units which burn these coals.  Low sulfur, low rank Western coal would be
classified in the proposed regulations as "subbituminous coal," according
to ASTM standards.  There may be some Western bituminous coals which have
high tube wastage potentials due to high sulfur contents.  The combustion
of these coals would be subject to the same emission limit as Eastern coals.

9.6  VISIBLE EMISSION STANDARDS
     There are.no visible emission regulations .associated with NO^ emissions.
An opacity standard has been proposed under Subpart Da, however, and this is
described in the Background  Information Document for Particulate Matter,."17

9.7  MODIFICATION AND RECONSTRUCTION  CONSIDERATIONS
     A modification is  defined  in 40  CFR Part 60,  Subpart A  and  in section  111
of the Clean Air Act  as any physical  or operational change to an existing
facility which  results  in  an increase in the  emission  rate to the  atmosphere
of any pollutant  to which  a standard  applies.   Upon modification,  an
existing facility  becomes  an affected facility (i.e.,  it becomes subject
to new source  performance  standards)  for each pollutant to which a standard
applies and for which there is  an  increase in the emission  rate to the
atmosphere.   Certain  exceptions to  the modification  rule are explained  in
                                     9-9

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 Subpart A and in Chapter 5.   Also,  Chapter 5 discusses  several  situations
 where changes to the pulverizer system,  combustion  air  system,  steam
 generation system,  draft system,  or fuel  combustion system could  cause
 an  increase in emissions,  and thus, cause a facility to be subject  to
 the modification rule.
      A reconstruction is defined  in Subpart A as  the replacement  of
 components of an existing  facility  to  such an extent that:
           The fixed capital  cost  of the new components  exceeds
      50 percent of  the  fixed capital cost that would be required
      to construct a comparable entirely new facility; and
           It is technologically and economically  feasible  to meet
      the applicable emission standards.
 An  existing facility,  upon reconstruction,  becomes  an affected  facility
 (i.e.,  it becomes subject  to new  source performance standards)  irrespective
 of  any  changes  in emission rates.   The reconstruction rule  is further defined
 in  Subpart A.
      Rather than modifying or  reconstructing  old  units, electric utilities
 generally prefer to  transfer these  units  from base  load to  standby status.
 Newer and  more  efficient units  then  assume  base load responsibility.
 Consequently,  it is  probable that few existing utility  steam generating
 units will  be modified  or reconstructed in  the future.

 9.8   SELECTION  OF MONITORING REQUIREMENTS
      The proposed regulations for NO  require that an initial performance
                                    X
 test  be performed just after startup of a new electric utility unit.  Once
 the performance test has been successfully completed, continuous compliance
with  the proposed emission limits would be required during the life of the
 unit.
                                     9-10

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     The initial performance test, as prescribed in section 60.8 of 40 CFR
Part 60, Subpart A, would be conducted within 60 days after achieving the
full load at which a new unit would be operated, but not later than 180
days after initial startup of the unit.  Compliance would be determined
by averaging emissions over a 24-hour daily period, from midnight to midnight.
The 24-hour daily period would be assumed to constitute three 8-hour runs,
thereby satisfying the requirement under §60.8 that a performance test consist
of the average of 3 separate runs.
     Following the initial performance test, continuous compliance with
the proposed emission limits would be required during the life of the unit.
Compliance would be determined by averaging all emission data recorded
for each 24-hour period.  Each 24-hour period would constitute a separate
performance test, and the owner or operator of a unit would be required
to report emissions in excess of the proposed limits.  The continuous
compliance requirement would not apply during startup and shutdown of a
unit.
     The decision to select an averaging period of 24 hours for continuous
compliance with the proposed emission limits is supported with continuous
monitoring emission data from a modern unit in the Western U. S, which burns
subbituminous coal.  These data indicate that NO  emissions can.-be successfully
                                                A
monitored on a continuous basis, and that emissions averaged over a 24-
hour period would not exceed the proposed emission limits.
     Compliance with the proposed emission limitations would automatically
assure compliance with the required percent reduction in uncontrolled
emission levels.  Thus, the percent reduction would not require performance
testing.

                                   9-11

-------
     EPA believes that continuous compliance with the proposed emission
limits is important to assure continuous operation of a boiler at low NO
                                                                        X
levels.  All testing would be performed according to procedures described in
Subpart Da and Reference Method 19.

9.9  SELECTION OF PERFORMANCE TEST METHODS
     A continuous monitoring system which meets Performance Specification
12 for oxides of nitrogen and Performance Specification #3 for oxygen or
carbon dioxide, as described in 40 CFR Part 60 Appendix B, would be
required for performance testing.  In addition, the zero and calibration
span drift of the monitors must be checked and monitoring data reported
according to procedures described in Appendix D (D.3) of this document
and in Reference Method 19.
     Although departures were made from the performance specification
procedures during EPA testing, sufficient care was taken to assure that
the departures did not adversely affect the test results.
                                    9-12

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                       REFERENCES FOR CHAPTER 9

1.  Standards Support and Environmental Impact Statement, Volume 1:
    Proposed Standards of Performance for Lignite-Fired Steam
    Generators.  Emission Standards and Engineering Division, Office
    of Air Quality Planning and Standards, U. S. Environmental
    Protection Agency.  Research Triangle Park, North Carolina.
    Report Number EPA-450/2-76-030a.  December, 1976.  190 p.
2.  U. S.  Environmental Protection Agency.  Proposed amendments to
    Standards of Performance for New Stationary Sources (Lignite-
    Fired Steam Generators).  40 CFR part 60, Subpart D.  Washington,
    D. C.  Federal Register (41 FR 55792).  December 22, 1976.  3 p.
3.  Standards Support and Environmental Impact Statement, Volume 2:
    Promulgated Standards of Performance for Lignite-Fired Steam
    Generators.  Emission Standards and Engineering Division, Office
    of Air Quality Planning and Standards, U. S. Environmental
    Protection Agency.  Research Triangle Park, North Carolina.
    Report Number EPA-450/2-76-030b.  November, 1977.  30 p.
4.  U. S. Environmental  Protection Agency.  Promulgated amendments to
    Standards of Performance for New Stationary Sources (Lignite-Fired
    Steam Generators).  40 CFR Part 60, Subpart D.  Washington, D. C.
    Federal Register (43 FR 9276).  March 7,  1978.   3 p.
5.  U. S. Environmental  Protection Agency.  Promulgated amendments to
    Standards of Performance for New Stationary Sources (Coal Refuse).
    40 CFR Part 60,  Subpart D.  Washington,  D.  C.   Federal  Register
    (40 FR 2803).   January 169 1975.  1  p.
                                  9-13

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 6.  Test Report on Nitrogen Oxide Emission from Unit No. 1 at Southern
     Illinois Power Cooperative, Marion, Illinois (Corrected).  Burns
     and McDonnell.  Kansas City. Missouri.  Project Number  73-108-1-000.
     Test Dates:  July 30 - August 2, 1974.  25 p.
 7.  Review of Burns and McDonnell Report on GOB Pile Burner NO  Emissions,
                                                               A
     Internal EPA Memorandum, Tom Logan to Don R. Goodwin.  September 20,
     1974.
 8.  Background Information for Proposed New Source Performance
     Standards:  Steam Generators, Incinerators, Portland Cement Plants,
     Nitric Acid Plants, and Sulfuric Acid Plants.  Office of Air
     Programs, U.S. Environmental Protection Agency.  Research Triangle
     Park, North Carolina.  Report Number APTD-0711.  August, 1971.   54 p.
 9.  U. S. Environmental Protection Agency.  Proposed Standards of
     Performance for New Stationary Sources.  40 CFR Part 60, Subpart
     D.  Washington, D. C. Federal Register (36 FR 15704).  August 17,
     1971.  19 p.
10.  U. S. Environmental Protection Agency.  Promulgated Standards of
     Performance for New Stationary Sources.  40 CFR Part 60, Subpart
     D.  Washington, D. C.  Federal Register (36 FR 24876).  December 23,
     1971.  20 p.
11.  Fuel Gas Environmental  Impact:  Phase Report.  Industrial  Environ-
     mental  Research Laboratory, Office of Research and Development,
     U. S. Environmental Protection Agency.  Research Triangle Park,
     North Carolina.  Report Number EPA-600/2-75-078.  November,  1975.
     314 p.
                                     9-14

-------
12.  Burner Design Criteria for NOX Control from Low-Btu Gas Combustion,
     Volume 1:  Ambient Fuel Temperature.  Industrial Environmental
     Research Laboratory, Office of Research and Development, U.S.
     Environmental Protection Agency.  Research Triangle Park, North
     Carolina.  Report Number EPA-600/7-77-094a.  August, 1977.  119 p.
13.  Burner Design Criteria for NOV Control from Low-Btu Gas Combustion,
                                  /\
     Volume II:  Elevated Fuel Temperature.  Industrial Environmental
     Research Laboratory, Office of Research and Development, U. S.
     Environmental Protection Agency.  Research Triangle Park, North
     Carolina.  Report Number EPA-600/7-77-094b.  December,  1977.  84 p.
14.  Preliminary Environmental Assessment of Combustion Modification
     Techniques,  Volume II: Technical  Results.  Industrial  Environmental
     Research Laboratory, Office of Research and Development, U. S.
     Environmental Protection Laboratory.  Research Triangle Park,  North
     Carolina.  Report Number  EPA-600/7-77-119b.  October,  1977.  578 p.
15.  Characteristics of Solvent Refined Coal:   Dual Register Burner Tests,
     Electric Power Research Institute.  Palo  Alto, California.  Report
     Number EPRI  FP-628.  January, 1978.  109 p.
16.  Electric Utility Steam Generating  Units:   Background Information for
     Proposed Sulfur Dioxide Emission Standards.  Emission Standards and
     Engineering Division,  Office of Air Quality Planning and Standards,
     U.  S.  Environmental  Protection Agency, Research Triangle Park,
     North  Carolina.   Report Number EPA 450/2-78-007a.   July, 1978.
                                     9-15

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17.  Electric Utility Steam Generating Units:   Background  Information for
     Proposed Participate Matter Emission Standards.   Emission  Standards and
     Engineering Division, Office of Air Quality Planning  and Standards,
     U. S. Environmental  Protection Agency,  Research  Triangle Park,
     North Carolina.  Report Number  EPA-450/2-78-006a.  July,  1978.
18.  Compilation of Air Pollutant Emission Factors (Second Edition).
     Monitoring and Data Analysis Division,  Office of Air  Quality
     Planning and Standards, U. S. Environmental Protection Agency,
     Research Triangle Park, North Carolina.  Report  Number AP-42.
     February, 1976.  Two Parts, 462 p.
                                     9-16

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          APPENDIX A



EVOLUTION OF PROPOSED STANDARDS

-------

-------
 A.I   GENERAL
      New source performance standards for NOV emissions  from steam
                                             X
 generators of more than 73 megawatts  (250 x TO6 Btu/hr)  heat input were
 proposed on August 17,  1971,  and were promulgated  December 23,  1971,
 under authority of the  Clean  Air Act  of 1970.   The foregoing Act  pro-
 vided that the Administrator  should,  from time to  time,  revise  these
 standards.   During 1975 it was  decided that there  were enough new
 developments in control  of N0x  emissions  from large steam  generators to
 warrant  considering revising  these  standards.   The new developments
 were,  that although no  new techniques  had been developed sufficiently
 since  1971  to  warrant consideration for new source performance  standards,
 it appeared that the N0x control  techniques  recommended for  achievement
 of the 1971  standards were more  effective than originally  projected.
 Consequently,  the  investigation  was purposely  directed toward deter-
 mining if  N0x  emission  limits lower than  the  1971  limits should be
 recommended.
     At  the  onset,  consideration of standards  for  lignite-fired steam
 generators was  eliminated  because standards development for  this
 category of  sources was nearly complete.
     The study was  initiated in  late 1975 by making a thorough literature
 search of the thousands of references of the Air Pollution Technical
 Information Center of the U. S,  Environmental  Protection Agency (EPA),
 In January, 1976, the engineering staff of the EPA activity responsible
 for recommending new limits (Office of Air Quality Planning and Standards!
met with the engineering staff of the EPA activity responsible for
research and development (Control Systems  Laboratory, now called the
                           A-l

-------
 Industrial Environmental Research Laboratory).   Important parts of the
 data base used to recommend revised NO  control  limits were obtained
                                      J\
 from the Industrial  Environmental Research Laboratory  (IERL).
     The data provided by  IERL were sufficient to warrant further work
 on standards revision.  The foregoing preliminary study showed that at
 the end of 1975 there were no sources on line which were subject to the
 standards which became effective in 1971.  This was because of the
 five-year lead time  between commencement of construction of a large
 steam generator and  activation of the unit.  IERL advised, however,
 that there were several Combustion Engineering units and that there was
 one Babcock and Wilcox unit on line which, although not subject to the
 1971 standard, were  designed similar to the coal-fired steam generator
 designs which were being furnished to achieve the 1971 standard.  IERL
 had data which showed these units were capable of controlling NO
                                                                X
 emissions to levels  substantially below the limit of 300 nanograms per
 joule (0.07 lb/106 Btu) of the 1971 standard.  There were no similar
 data for large oil or gas-fired steam generators.
     Separate meetings were arranged with Babcock and Wilcox, Com-
 bustion Engineering, Inc., Foster Wheeler Energy Corporation, and Riley
 Stoker Corporation which, in total, furnish nearly all of the large
 steam generators installed in the United States.   These meetings
 occurred in February, 1976, and indicated to EPA that all  of the four
manufacturers were capable of furnishing coal-fired steam generators
which limit NO  emissions to levels substantially less than the 3QQ
              /\
 nanogram per joule ("0.07 lb/10  Btu]. limit promulgated in 1971.
                           A-2

-------
      In  February,  1976,  the tangential designs of Combustion Engi-



 neering,  Incorporated, were the best established because several



 Combustion  Engineering units were on line which had been tested at low



 N0x  levels.  There was one Babock and Wilcox unit on line which was an



 old  style unit equipped  with new specially designed burners and which



 was  equally effective in limiting NO  emissions.  Neither Foster Wheeler
                                    X


 or Riley Stoker had any  of their newest designs on line.  All four



 manufacturers said more  new design coal-fired steam generators would be



 coming on line during 1976 and subsequent years.



     All of the four manufacturers indicated concern about potential



 adverse side effects of  NO  control, such as corrosion, loss of boiler
                          A


 efficiency, high CO, etc. (See Chapter 4 and 6.)  Only Combustion



 Engineering said they were confident their designs could achieve low



 N0x  emission levels without adverse side effects.   The other three



 boiler manufacturers were uncertain and said they needed more experience.



     Subsequent to the February, 1976, meeting with the four boiler



manufacturers, a comprehensive data base was gathered based on the work



of IERL prior to February,  1976.  This data base was supplemented by



 IERL data and by Combustion Engineering data furnished later in 1976.



     In November, 1976,   EPA met with the National  Air Pollution Control



Techniques Advisory Committee in San Francisco.   At this meeting EPA



advised the Committee of plans to revise the NO  standard for large
                                               X


coal-fired steam generators from the 1971  limit of 300 nanograms per



joule (0.7 lb/10  Btu)  to a new limit of 260 nanogramss per joule (0.6



lb/10  Btu)  for all large solid fuel-fired sources  except lignite-fired



sources.    The concensus  of the Committee  was that  the lower limit was
                               A-3

-------
 feasible.  The four boiler manufacturers expressed positions similar to



 the positions already discussed in conjunction with the February,  1976,



 meetings.  In summary, Combustion Engineering said they were ready to



 achieve the lower limit.   The other three manufacturers said they  would



 like more time.



      EPA work on NO  standards revision was  limited during the  period
                    }\


 between the November, 1976,  National  Air Pollution Control  Techniques



 Advisory Committee Meeting,  and August, 1977.   This was because it was



 decided that it  would be  more efficient to propose changes  in the  NO
                                                                     A


 standard at the- same time as proposing  revisions  to the particulate and



 S02 standards.   Work on revising the  particulate  and S02 standards was



 not as  far advanced as the NOV standards  revision project.
                              X


      Another major change occurred  in August,  1977,  when the Clean Air



 Amendments of 1977 were enacted.  The Clean  Air Act of  1970  provided  for



 NOX standards  revision based on EPA judgment.   The 1977 amendments



 mandated that  the  standards  be revised.



      Further results  of IERL emission and  corrosion  testing of  tangentially-



 f.ired units  and  test  results  of Babcock and  Wilcox units  equipped  with



 specially designed  burning were added to the data  base  during 1977.   It



was  also  learned that  Babcock  and Wilcox and Foster  Wheeler had con-



 tracted  to each  furnish a  large coal-fired steam generator for the  San



Juan  Station of  Public Service  Company of  New Mexico. These units were



to be subject to the New Mexico  NO  regulation of  190 nanograms oer
                                  y\                             '


joule (0.45  lfa/106 Btu).



     Based on this additional data, EPA decided to revise the original



recommendation for solid fuel, other than lignite-fired sources, of 260
                               A-4

-------
  nanograms  per joule (0.6 lb/106 Btu)  to  one of 210 nanograms  per joule



  (0.5  lb/10  Btu)  for large  subbituminous coal-fired units  and 260



  nanograms  per joule (0.6 lb/106 Btu)  for all other large solid fuel  (except


  lignite) fired sources.   In addition, the  recommendations  were revised


  to require a  percent  emission reduction  as  stipulated by the  Clean Air


 Amendments of 1977.



      During December, 1977, the revised  recommendations were  reviewed



 before a Working Group composed of all interested EPA activities and at



 a separate meeting of the National Air Pollution Control Techniques



 Advisory Committee.  The consensus of the participants of both meetings


 was that recommendations for proposed N0y standards were feasible.
                                         A


      During the period between  December  1977 and August  1978 further data


 on control  of NOX  emissions  from Babcock  and Wilcox, Foster Wheeler,  and


 Riley  Stoker  boilers were incorporated in the document.   Limited data was


 also added  on  the  effect  of  NOX  control on  polycyclic organic  matter


 emissions.  Data on continuous monitoring of NO   emissions  was added  in
                                               /\

 February, 1978.  Further  testing was conducted in April  and  again  in  June,



 1978 to evaluate the  integrity of the  NOX continuous  emission monitoring


 data.  Although the final results of the April and June  testing are not


yet available, preliminary results indicate  the data  is  probably valid.
                                 A-5

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-------
                              APPENDIX B



             INDEX TO ENVIRONMENTAL IMPACT CONSIDERATIONS





     This appendix consists of a reference system Which is cross-indexed



with the October 21, 1974, Federal Register (39 FR 37419) containing EPA



guidelines for the preparation of Environmental Impact Statements.  This



index can be used to identify sections of the document which contain data



and information germane to any portion of the Federal Register guidelines.
                                   B-l

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-------
   APPENDIX C



SOURCE TEST DATA

-------

-------
                               EXHIBIT I

 Basic  Source  Test  Data  References

 1.   Crawford, A.  R., E.  H.  Manny,  and W.  Bartok,  The  Effect of
     Combustion Modification on  Pollutants  and  Equipment  Performance
     of Power Generation  Equipment,  Exxon  Research and Engineering
     Company, Linden, New Jersey, September 1975.
 2.   Program  for Reduction of N0v from Tangential  Coal-Fired
                                 X
     Boilers, Phase  II, EPA-650/2-73-005-a,  Office of  Research  and
     Development,  U. S. Environmental Protection Agency,  Research
     Triangle Park, North Carolina, June 1975.
3.   Selker, A. P., Overfire  Air as a NOV Control  Technique  for
                                        A
     Tangential Coal-Fired Boilers, Combustion  Engineering,  Incorporated,
     Windsor, Connecticut, September 1975.
4.   Campobenedetto, E.  J., The Dual Register Pulverized Coal Burner--
     Field Test Results, Presented at the Engineering  Foundation
     Conference on Clean Combustion of Coal, Franklin  Pierce College,
     Rindge, New Hampshire, July 31  to August 5, 1977.
5.   Overfire Air Technology for Tangentially Fired Utility Boilers
     Firing Western U.  S.  Coal, EPA 600/7-77-117, U. S. Environmental
     Protection Agency,  Research Triangle Park,  North Carolina,
     October 1977.
     Vatsky, J., Attaining Low NO  Emissions by  Combining  Low Emission
                                 X
     Burners and Off-Stoichiometric  Fining,  Foster  Wheeler Energy
     Corporation,  Livingston, New Jersey,  November  1977.
6.

-------

-------
 C-E Power Systems
 Combustion Engineering. Inc.
 1000 Prospect Hill Road
 Windsor. Connocticut 06095
   EXHIBIT  II

Tel. 203/688-1911
Telex: 9-9297
 POWER
 SYSTEMS
                FOR:   John  Cope!and, Room 754  RUSH
                       Telecopied October 8, 197F
                                 October 8, 1976
 Mr. John Copeland
 United States Environmental Protection Agency
 Office of Afr Quality Planning and Standards
 Research Triangle Park
 North Carolina 27711

 Dear Mr. Copeland:

 Would you please include the following disclaimer notice with
 the data that we sent to you on April  6,  1976,  since you are
 publishing this data verbatim:

                       LEGAL NOTICE

    "This data was prepared By Combustion  Engineering, Inc.
    for the United States Environmental  Protection Agency.
    Combustion Engineering, Inc.  nor any person  acting on
    its behalf;  (a) mattes any warranty  or  representation,
    express or implied including  the warranties  of fitness
    for a particular purpose or merchantability, with respect
    to  the accuracy,  completeness,  or usefulness of the
    information  contained in this report,  or that  the use
    of  any information,  apparatus,  method, or process dis-
    closed in  this report may not infringe privately  owned
    rights;  or  (b)  assumes any liabilities with  respect to
    the use, of, or for  damages resulting  from the  use of,
    any information,  apparatus, method or  process  disclosed
    in  this  report."

                                Sincerely yours,

                                COMBUSTION ENGINEERING,  INC,
                                Henry E/ Burbach
                                Director, Proposition Engineering
HEB:mm
                                    C-II-1

-------
     C-E Power Systems
     Combustion Engineering. Inc.
     1000 Prospect Hill Road
     Windsor. Connecticut 06095
Tel. 203/688-1911
Telex: 9-9297
     POWER
     SYSTEMS
                                            November 11, 1977
Mr. George B. Crane, P.E.
Industrial Studies Branch
Emission Standards & Engineering Division                              ,
United States Environmental Protection Agency
Research Triangle Park, North Carolina 27711

Dear Mr. Crane:

The following are our answers to your questions posed in your October  21, 1977
letter:

Question 1:  Does C-E maintain their statement made on our visit of February  19,
             1977, to guarantee their new boilers to meet a 0.6 lb/10° Btu NOx
             limit with Eastern coals and 0.5 Ib limit for other coals?

Answer:      Yes, C-E still will maintain this position.

Question 2:  Can new C-E boilers meet a 0.5 limit across the board?  If so, could
             C-E so guarantee?

Answer:      No, C-E does not feel that 0.5 NOx limit can be met across the board
             v/ith all fuels.

Question 3:  Does C-E know of any feasible way to characterize or describe a
             "Western" or an "Eastern" coal for purposes of standards  setting?

Answer:      Characterization of Eastern vs. Western coal can be accomplished by
             evaluating the coal in the ASTM ranking scale.  Those coals which
             rank higher in heating value than 11,000 Btu/lb on a moist, mineral
             matter free basis which classify as hi-volatile "C" or sub-bituminous
             "A" (and above), we would characterize as Eastern coal.   Those below
             11,000 Btu/lb which are sub-bituminous "B", "C" and lignite would
             classify as Western coal for this purpose.  There are coals found
             in the Rocky Mountain area which classify as hi-volatile  "C", sub-
             bituminous "A" and above.

             Attached is a copy of a C-E standard sheet #61-038 which  graphically
             displays the ASTM ranking.

Question 4:  Our trip report (item no. 1) states that C-E "does not recommend
             tying the limits of a NOx standard tc coal analysis".  Does C-E
             maintain this opinion?
                                        C-II-2

-------
 Mr. Georcje B. Crane, P.E.
                            -2-
                                                            November 11, 1977
 Question 4: cont'd
 Answer:
HEB:mm
attach.
Yes, we still believe that we can not identify constituents in the

         '            Suffic1entl* wel1 to <"«*«* relate to a
 Question 5:
 Answer:
This would be beyond the classification outlined above for item no  3
where we make a gross differentiation of fuel type by analysis.

Do you have NOx source test data and boiler operation, maintenance
and performance reports for new boilers on line since spring«of
1976?  is there any indication of tribe corrosion and wastage-however
small -for how NOx operation mode?                             "imever

The only recent tests for tube corrosion were at Utah Power & Liqht
Huntington Canyon Station and Wisconsin Power & Light, Columbia

                       Wh1ch indicated no evidence of
              On  other C-E  units with OFA  in operation, we have had no reports
              of  operational difficulties  or corrosion on wastage problems
              These units have not been specifically surveyed for problems.

                                       Sincerely yours,
                                       COMBUSTION ENGINEERING, INC.
                                                       -»-*—"C-& &
                                                Burba'ch
                                                 Proposal Engineering
                                            C-II-3

-------
                                         PULVERIZERS
                                   COAL  CLASSIFICATION
                    EHOIHEERIHG  OEPT.  STANDARDS    SHEET  HO. 61-038
o
•h
    78
    1C.OCO
                                                         DEFINITIONS
                                  ORy. H-H-FREE ra.  PERCENT =
                                  HOIST. M-M-FREE 8TU, PER POUS.O =
                                                                 100 -
                       M-H - MINERAL HATTER


                       BTU - HEATIHG VALUE


                       FC  - FIXED CARBON, %


                       VH  - VOLATILE HATTER,  1


                       H  .--BED MOISTURE, S


                       A   - ASH, t


                       S   '- SULPHUR, %
14.000
                , A bit-
                         HI.-VO!
13.000            11.000        9.500
  I MOIST. MINERAL-MATTES-FREE B.T.U.
      Hi.-vol. C bit.
                         B bit  '     or subbit A    '     B
                                                C-II-4
8,300
                                                               Subbit
                                          -Lignite
                                                                                     X »0
       r,w  py r. I «F Ft? I wr.   \uc

-------
      C-E Power Systems
      Combustion Engineering, Inc.
      1000 Prospect Hill Road
      Windsor, Connecticut 06095
 Tel. 203/688-1911
 Telex: 9-9297
      POWER
      SYSTEMS
         July 30, 1976
Mr.  John  0.  Copeland
Industrial Studies  Branch
Emission  Standards  &  Engineering  Division
United  States  Environmental  Protection Agency
Research  Triangle Park
North Carolina 27711

Dear Mr.  Copeland:

The  attached information  has  been prepared  in response to your letter of
June 2, 1976,  for NOx emission  data  on C-E  pulverized coal-fired steam gener-
ators.  Specifically, you requested  the following  in  addition  to NOx emission
levels:

     a.   Ultimate analysis,  ash analysis, and heating value  of the  coal  fed to
          the pulverizers  during testing.

     b.   Description  of combustion air adjustments  during testing.

     c.   Boiler load  during  testing.

     d.   Concurrent data  on CO, Q2>  CQ2>  ash  combustible  content, hydrocarbons,
          and polynuclear  organic matter emissions.

     e.   Corrosion test results.

     f.   Corrollary data  on test methods.
The attached Summary of Field Test Data covers items "a" thru "e" of your request.
C-E field test data from 14 units, ranging in plan area from 408 sq. ft. to
2760 sq. ft. and in rating from 50 Mw to 600 Mw, is presented.  The coals fired
in these units are as follows:
     High Sodium Lignite
     Texas Lignite
     Western Sub "C"
     Western Sub "B"
     Western Bituminous
     Mid-Western Bituminous
     Eastern Bituminous
Units A,B
Unit C
Units D,E
Units F,6
Units H,I,J
Unit K
Units L.M.N
                                         C-II-5

-------
Mr. John Cope!and
-2-
July 30, 1976
An analysis by you of the data presented should lead to the following conclusions:

     a.  That C-E tangenti ally-fired boilers are capable of meeting the present
         EPA limit for all coal types at normal excess air levels (20-25% excess
         air),

     b.  that excess air has a predominating effect on NOx emission levels for
         all coal types,

     c.  that overfireair is extremely effective in reducing NOx emissions from
         tangenti ally-fired boilers for all coal types,

     d.  that for Eastern Bituminous coals, tangenti ally-fired boilers would be
         capable of meeting an 0.6 Ibs. N02/MMBTU emission limit when equipped
         with overfire air,

     e.  that for the lower rank Western coals and lignite, tangenti ally-fired
         boilers would be capable of meeting an 0.5 Ibs. N02/MMBTU emission
         limit when equipped with overfire air, and

     f.  that increased waterwall corrosion rates, increased CO emissions, and
         increased ash combustible content when operating with overfire air
         for NOx control is not a problem on tangenti ally- fired boilers.

No data is given for unburned hydrocarbon or polynuclear organic matter emissions,
When measured, unburned hydrocarbons have always been less than 2 PPM on C-E
coal-fired boilers.  C-E has never attempted to measure emission of polynuclear
organic matter.

The second attachment discusses the three NOx measurement methods employed by
C-E in our field test program.  A brief discussion of the various methods,
including the advantages and disadvantages, as well as a comparison of actual
NOx field test data obtained by the three methods, is presented.

Should you require any additional information, please feel free to contact
me.

                                        Very truly yours,

                                        COMBUSJIQN  NGINEERING, INC.
                                           E. Burbach
                                        Director, Proposition Engineering
:mm
attach.
                                        C-U-6

-------
                      Summary of Field Test Data
                          Unit Identification
Unit                 Utility

 A       Ottertail Power

 B       Saskatchewan Power Corp.

 C       Industrial Generating Co.

 D       Public Service Co. of Colorado

 E       Minnesota Power & Light Co.

 F       Utah Power & Light Co.

 G       Utah Power & Light Co.

 H       Utah Power & Light Co.

 I       Public Service Co. of Colorado

 J       Utah Power & Light Co.

 K       Union Electric Co.

 L       Alabama Power

 M       Cincinnati Gas & Electric

 N       Tennessee Valley Authority
    Station              Tested

Hoot Lake #2             11/70

Boundary Dam #4           3/73

Big Brown #1            5/72-8/72

Comanche #1               2/74

Clay Boswell #3           4/74

Naughton #2             7/70-8/70

Naughton #3               9/72

Gadsby #3                 5/71

Cherokee #4               1/72

Huntington Canyon #2    5/75-9/75

Labadie #1                6/71

Barry #4                  1/73

Beckjord #6              10/69

Widows Creek #7B          4/71
Note:

1.   'NA' in the column labled OFA Damper Setting means the unit was not
    equipped with overfire air.

2.  * in the column labled OFA Damper Setting indicates that overfire air
    was simulated by operating the top elevation of nozzles on air only.

3.  All damper settings are given as percent open, 0 meaning fully closed,
    100 meaning fully open.

4.   'NR1 means NOT RECORDED.

5.  Higher heating value is given in BTU/LB, as received basis.
                                   C-II-7

-------

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C-II-21




-------
                      NOx Measurement Techniques






    Combustion Engineering's Field Testing Department currently employs




three methods for determining NOx emission levels- from coal—fired steam




generators.  These are the Phenol-Disulfonic Acid Method (ASTM 1608-60),




the Whittaker Dynascience Electrochemical NOx Analyzer, and the Scott




Chemiluminescence NOx Analyzer.  The advantages and disadvantages of each




method are noted in Table 1.  These methods compare favorably with each




from a standpoint of accuracy as shown in Figure 1 which is based on actual




test data obtained on a coal—fired steam generator.






    The Phenol-Disulfonic method was adopted in 1969 when C-E's  NOx  field




test program was initiated.  In this method, a gas sample is admitted to




an evacuated flask containing an oxidizing absorbent consisting of hydro-




gen peroxide in dilute sulfuric acid.  The nitrogen oxides in the gas




(both NO and N0?) are converted to nitric acid by the absorbing solution




and the resulting nitrate ion reacted with phenol-disulphonic acid to pro-




duce a yellow solution which is measured calorimetrically against calibra-




tion curves prepared from samples of known nitrate content.  This method is




known to be accurate to 5 percent and is repeatable.   A major disadvantage




is that this method is time consuming and not suitable for optimization




tests where immediate results and continuous monitoring are desirable.




The Phenol-Disulfonic Acid Method is employed by C-E whenever EPA NOx com-




pliance testing is being performed and also to verify the NOx content of




bottled gases used to calibrate the Whittaker and Scott instruments..  The




method is not used extensively in C-E's on-going field test program bacause




of the lengthy analysis period required.
                                   C-II-22

-------
 Waterwall Corrosion Testing







     The effect of biased firing and overfire air operation  on waterwall  '




 corrosion potential was evaluated  during  three thirty  (30)  day baseline,




 biased firing and overfire  air  corrosion  coupon tests  conducted at the




 Alabama Power Co.,  Barry Station #2 generator under  EPA contract #68-02-




 1367.   The results  of  said  testing are  reported in detail in  EPA-650/2-




 73-005,  entitled  "Program for Reduction of NOx from  Tangential Coal-Fired




 Boilers—Phase II",  dated June  1975.  Briefly,  the results  of these




 corrosion tests indicated that  the weight loss  experienced  by the test




 coupons  during the  thirty day test periods were within  the  range to be




 expected from the normal  oxidation of carbon  steel.  That is, the results




 did not  show  any  significant increase in  waterwall corrosion  during biased




 firing or overfire air  operation for NOx  control.







    Additional  waterwall  corrosion  testing, performed by C-E under EPA




 contract, has recently  been completed at Utah Power and Light, Huntington




 Canyon #2.  The .preliminary results again indicated no significant change




 in waterwall corrosion when operating in  the low NOx modes.   Further infor-




mation should be available from the EPA Project Officer, Mr. David G.




Lachapelle.







    Waterwall corrosion testing is  to be carried on at Wisconsin Power and




Light, Columbia #2, under EPA contract later this year.   No  other waterwall




corrosion testing has been performed by  C-E.
                                   C-II-23

-------
                                  -2-






    In late 1969, C-E began using the continuous recording Whittaker




Dynascience Electrochemical NOx Analyzer when taking NOx measurements in




the field.  This instrument is an electrochemical transducer in which the,




gas sample passes through a membrane, dissolves in a thin layer of electro-




lyte, diffuses to a sensing electrode where electrons are released with the




current flow being proportional to the NO partial pressure.  The instrument




has been found satisfactory in accuracy and response when proper precautions




are taken to ensure that S0_ and So., are scrubbed out of the gas sample and




that the sensing cell is maintained at constant temperature.  The instrument




requires calibration with a gas mixture of known NO content.  The Whittaker




Dynascience Electrochemical NOx Analyzer is currently employed by C-E in




short duration field test programs.






    In 1973, C-E received delivery of a Gaseous Emission Test System




developed by C-E's Field Test Department, in conjunction with Scott Labora-




tories, for performing environmental testing in the field.  The system will




continuously monitor and record NOx, 0», CO and hydrocarbons present in the




flue gas.  The system is contained in an air conditioned, self-propelled,




mobile emission van.  The system is equipped with a Scott Chemiluminescence




NOx analyzer.  This instrument monitors.the infra-red radiation which is




emitted when the gas stream containing NO is mixed with ozone in a reaction




chamber.  An N0_ to NO converter is incorporated in the Chemiluminescence




analyzer so that the small amount of N0_ present in the flue gas will also




be measured.  The Chemiluminescence analyzer can provide an extremely




stable, accurate, and fast response method of measuring NOx in combustion




gases if the gas sample is dried prior to measurement and a constant cell




temperature  is maintained.   The instrument requires calibration with a gas




mixture of knoxm NO content.  C-E employs the Scott Chemiluminescence NOx




Analyzer in all longer duration field test programs.




                                    C-II-24

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-------
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                                        Figure 1
                        Comparison of NOx Measurement Techniques

                      ASTM Method Vs. Whittaker &  Scott Analyzers
          700
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200
•300
400
500
                                                                     600
700
                              ASTM Phenoldisulfonic Method



                             PPM - Adj.  to 3% 02,  Dry Basis
                                             C-II-26

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                  APPENDIX D



EMISSION MEASUREMENT AND CONTINUOUS MONITORING

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        APPENDIX D.   EMISSION
AND CONTINUOUS MONITORING
 D.I  EMISSION MEASUREMENT METHODS
      The data gathered to support the oxides  of nitrogen standard for'fossil
 fuel-fired steam generators were taken from research and development studies
 conducted by Exxon Research for EPA under  contract  £EPA Contract  68-02-1415
 and EPA Report  650/2-73-005a).   As described  in these reports, a  chemi-
 luminescent instrument with a thermal reactor to measure both nitric oxide
 and nitrogen dioxide and  a nondispersive infrared (NDIR)  analyzer for nitric
 oxide and nondispersive ultraviolet (NDUV)  for  nitrogen dioxide were used.
 Oxygen was also measured  so that the  oxides of  nitorgen emissions  could be
 corrected to 3  percent oxygen.
      The contractor reports included  insufficient details on the  test data
 and sampling techniques (instrument zero and  calibration responses and
 sampling probe  locations) to enable an evaluation of  the quantitative accu-
 racy  of  the measurements.  However, from statements written in the reports,
 it was concluded that  the contractor  followed all the necessary procedures
 to ensure valid measurements, i.e., daily calibration, recalibration when
 zero drift was appreciable,  well maintained instruments, certified calibration
    i
 gases, and a multipoint sample system to remove any gas concentration
 stratification.

D.2  CONTINUOUS MONITORING
     EPA has established monitoring performance specifications in Appendix B
of 40 CER Fart 60.  The specifications were developed for large industrial

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g sources, including power plants.  Continuous monitoring data are available
  to demonstrate the applicability of monitors to measure and record oxides
  of nitrogen and oxygen or carbon dioxide.
       The decrease in the level of the oxides of nitrogen standard will not
  affect the feasibility of continuous monitoring at power plants.   Oxygen or
  carbon dioxide can also be measured to convert the concentration data into
  units of the standard (nanograms per Joule).
       The costs of gaseous pollutant monitors for oxides of  nitrogen and
  oxygen or carbon dioxide have been estimated in the range of $30,000 capital,
  $5,000 installation,  $3,000 to $7,000 performance tests,  and $16,000 annual
  operating.   Facilities which have need for more than one monitor  could
  reduce their total cost by selecting an extractive, type system and by time
  sharing the system between several locations.

  D.3  PERFORMANCE TEST METHODS
1       A continuous monitoring system that meets  Performance  Specification #2
  for oxides  of nitrogen and Performance Specification #3 for oxygen or carbon
  dioxide which are set forth in 40 CFR 60 Appendix B, is recommended as the
  performance test method.   In addition to the performance specifications, the
  zero  and  calibration  span drift  of the monitors is recommended to be checked
  at  least  once per 24-hour period of performance averaging time.  These checks
  should be made in accordance with 40  CFR 60.13  (Subpart A - General Provisions,
 Monitoring  Requirements).   The monitoring data  are recommended to be expressed
  in  terms  of the proposed  standard (nanograms/Joule heat input) by using
  the calculation procedures  specified  in proposed EPA Method 19, "Determination
 of  Sulfur Removal Efficiency of Fuel Pretreatment and Sulfur Dioxide Control
 Systems and Determination of Particulate, Sulfur Dioxide, and Nitrogen Oxides
 Emission Rates  from Fossil Fuel-Fired Steam Generators."

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    APPENDIX E



ENFORCEMENT ASPECTS

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E.I  GENERAL
     The candidate affected facilities discussed in this document are
limited to electric utility (other than lignite) fired steam generators
of more than 73 megawatts (250 x 10  Btu) gross heat input.
     As discussed in Chapter 5, some changes in steam generators can
cause existing sources to become subject to new source performance
standards for modified or reconstructed sources.
     The rules and regulations for determining if a source will be
subject to new source performance standards by reason that the source
is new, modified, or reconstructed, are given in Subpart A, Part 60,
Subchapter C, Chapter 1, Title 40, Code of Federal  Regulations.  In
view of the multi-million dollar capital  costs of Targe steajn generators,
it is suggested that interpretation of the foregoing rules and regu-
lations be reviewed through the U. S. Environmental  Protection Agency
Regional Office Enforcement Division for the region where a source will
be located.
     The locations and addresses of these regional  offices are as
follows:
     Region I - Connecticut, Maine, Massachusetts,  New Hampshire
                Rhode Island,  Vermont
     John F.  Kennedy Federal Building
     Boston,  MA  02203
     Telephone:  617-223-7210
     Region II - New Jersey, New York,  Puerto Rico,  Virgin Islands
     26 Federal Plaza
     New York, NY  10007
     Telephone:  212-264-2525
                               E-l

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  I

Region III - Delaware, District of Columbia, Maryland,
             Pennsylvania, Virginia, West Virginia

Curtis Building
6th and Walnut Streets
Philadelphia, PA  19106
Telephone:  215-597-9814

Region IV - Alabama, Florida, Georgia, Mississippi,
            Kentucky, North Carolina, South Carolina,
            West Virginia

345 Court!and, N.E.
Atlanta, GA  30308
Telephone:  404-881-4727

Region V - Illinois, Indiana, Michigan, Minnesota,
           Ohio, Wisconsin

230 South Dearborn
Chicago, IL  60604
Telephone:  312-353-2000

Region VI - Arkansas, Louisiana, New Mexico, Oklahoma, Texas

First International Building
1201 Elm Street
Dallas, Texas  75270
Telephone:  214-767-2600

Region VII - Iowa, Kansas, Missouri, Nebraska

1735 Baltimore Street
Kansas City, MO  64108
Telephone:  816-374-5493

Region VIII - Colorado, Montana, North Dakota,
              South Dakota, Utah, Wyoming

1860 Lincoln Street
Denver, CO  80295
Telephone:  303-837-3895

Region IX - Arizona, California, Hawaii, Nevada,  Guam,
            American Samoa

215 Fremont Street
San Francisco, CA  94051
Telephone:  415-556-2320
                          E-2

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 Region X - Washington, Oregon, Idaho,, Alaska
 1200 Sixth Avenue
 Seattle, WA  98101
 Telephone:  206-442-1220
 E.3  COMPLIANCE

      General  procedures for compliance testing and emission monitoring

 are specified in Subpart A, Part 60,  Subchapter C, Chapter 1,  Title 40,

 Code of Federal  Regulations.   Special  regulations  for compliance testing

 and emisssion monitoring for N0x emissions  from electric  utility steam

 generators  will  be  specified in  Subpart D(a),  Part 60,  Title 40,  Code  of

 Federal  Regulations.   In summary,  these regulations would require that

 new sources be tested  for compliance after  shakedown  and  that  sources

 be  equipped for  N0x continuous compliance monitoring.   These emission

 monitoring  systems must be  field tested for accuracy.

      Continuous  emission monitoring is  the  most  important method  for

 determining if a  source is  in compliance with  NO   new source performance
                                                 /\
 standards for  pulverized coal-fired steam generators.  As discussed in

 Chapter  6,  N0x emissions  from modern low NOX emission design steam

 generators  can vary widely  depending on the way the unit  is  operated.

 Consequently,  unless N0x emissions are monitored at all times, a  source

 tested for  compliance after shakedown might be subsequently operated

with N0x emission levels substantially exceeding the regulatory limit,

 thereby circumventing the purpose of the emission limitation.
                            E-3

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          APPENDIX F



BASIS FOR DISPERSION ESTIMATES

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 F.I  GENERAL
      An analysis war, made to assess the ambient concentrations of pollutants
 which would result from HOX emissions from pulverized coal combustion/  For
 the purpose of.the study, it was assumed NOX pollutants behave as non-reactive
 gases.

 F.2  PLANT CHARACTERISTICS
      Table F-l  gives information on the plants studied.1   All  plants were
 pulverized coal-fired steam generators controlled to meet  an NOX limit of 300
 nanograms  per joule (0.7 lb/106 Btu).
      Heat  rate  was  assumed to  be 10.56 megajoules (10,000 Btu)  per kilowatt
 hour generated  from combustion.   Plants  equipped with  75, 175,  275 metre
 (246,  574,  and  902  ft)  stacks  were  studied.   Estimated heights  of tall
 structures  near the stacks are'given  in  Table F.I.
      It was assumed that plants  would  operate at all times  during a year at
 full  load capacity.

 F.3  MODEL  TECHNIQUES
     A suirmary  description of  the models is given in Sections F.5  and F.6.
   . The model was  programmed to derive a set of dispersion conditions for  the
 basic meteorological data  for each hour of the given year.  The calculations
 simulated the interaction between the plant characteristics and these dispersion
 conditions to produce a dispersion pattern for each hour.   These computations
were performed for each point in an array of  180 receptors encircling the plant
and extending downwind from the site.   Values were calculated at each of the
receptors for each hour and were integrated and averaged to calculate a mean
annual average.
                                   F-l

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     The aerodynamic effects of surrounding structures were analyzed
according to the procedures summarized in Section F.6.
     It was assumed the plant would be located in flat or gently
rolling terrain with a meteorological regime unfavorable to the
dispersion of effluents.
     Preliminary analysis indicated that for the plants a combination
of unstable atmospheric conditions and relatively low wind speeds would
produce the highest short-term concentrations.  If such conditions
occurred frequently at a given location, especially if they were
combined with a high directional bias in the wind, then longer term
impacts (e.g., 24 hours and annual) would tend to be high.
     For Cases 1-3, preliminary analysis showed that Burbank, Calif-
ornia, satisfied the conditions of relatively low wind speeds with
moderate persistence and unstable atmospheric conditions.  Upper air
sounding data from Santa Monica, California, were combined with the
surface station data.
     For Cases 4-9, the preliminary analysis suggested slightly higher
wind speeds and unstable atmospheric conditions.  Oklahoma City,
Oklahoma, satisfied these conditions.  Although on an annual-average
basis the wind speed at Oklahoma City is quite high, two features
tend to offset this fact:  a high annual wind-direction-frequency
(22 percent from SSE) and the fact that when the wind is from this
sector, atmospheric conditions tend toward the unstable.  Upper air
observations from Oklahoma City, Oklahoma were combined with the
surface data.
     Related to the choice of plant location is the selection of
source-receptor distances.  Preliminary analysis indicated that the
                               F-3

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model plants exert maximum impact relatively close-in.  In light of the
preliminary analysis, distances selected are shown in Table F-2.
F.4  RESULTS AND DISCUSSION
     The maximum pollutant concentrations for the specified averaging
periods for all nine cases considered are listed in Table F-3.
These concentrations have been pro-rated according to their respective
emission rates.  The five receptor distances chosen are listed in Table F-2.
     Retardation, although it occurs frequently during the year in  all
cases, is not the controlling .factor in producing maximum concentrations.
In Case No. 7, downwash occurs most of the time and does produce
the maxima concentrations.  The 3- and 24-hour maxima values are
not representative of unique meteorological situations with the
exception of Case No. 7.  Numerous values in the individual maxima
ranges were noted on different days at widely separated grid points
at source-receptor distances similar to those reported for each case
in Table F-3.  This is to say then, that with the exception of Case
No. 7 (downwash), concentrations similar to those shown in Table F-3
for the individual pollutants are common.  It is noticeable generally
that as the stack heights increased for a given plant size, the concentration
decreased.
     The annual-average concentration distributions displayed  the
expected dependence upon  the wind-direction frequency distributions
for each meteorological choice.  Generally, concentration  values
similar to those shown in Table F-3 for each of the nine cases
(for each individual pollutant) are confined to a sector approximately
9P° in width.  These concentration values were found at distances
similar to those shown in Table F-3 for each individual case.

                               F-4

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                                 TABLE F-21
Case
No.
1
2
3
4
5
6
7
8
9
Ring
1
0.3
0.3
0.3
1.0
1.3
2.6.
0.3
2.6
3.4
Source Receptor Distances (km.)
Ring Ring Ring
2 3 4
0.9
1.0
0.9
2.1
2.9
5.0
0.6
5.1
6.6
2.5
3.0
2.3
3.7
6.4
10.2
1.2
10.1
12.3
7.8
9.2
11.0
. 6.4
14.8
20.1
2.4.
20.5
23.3
Ring
5
23.0
38. 5
42.1
11.2
33.7
42.0
5.1
41.3
40.8
     These rings may be  viewed  as  the radii  of concentric circles around
the plant.  Receptors are  placed along each  174.5 mi 11iradian (10°) of azimuth,
thus accounting  for  th_e 180-receptor gH.d referred ;to_.previously.
                                    F-5

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                       TABLE F-31

       MAXIMUM POLLUTANT CONCENTRATIONS3
Averaging
Period
Annual








Case
1
2
3
4
5
6
7
8
9
NO
0.7
0.2
<0.1
1.6
0.5
0.2
930
0.7
0.4
Distance
N02 (km)
<0.1 0.9
<0.1 3.0
<0.1 2.3
<0.1 . . 6.4
<0.1 14.8
<0.1 20.01
14 0.3b
<0.1 20.5
<0.1 23.3
Concentrations have been pro-rated according to specific
emission rates.

First ring, downwash.
                          F-6

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 F. 5  DESCRIPTION OF THE DISPERSION MODEL
                                              . \
     Jhe model used to estimate ambient concentrations;^ Table F-3 for the
 pulverized coal-fired plants was one developed by the Meteorology
 Laboratory, U.S. Environmental Protection Agency, Research Triangle
 Park, N.C.  This model is designed to estimate concentrations due
 to sources at a single location for averaging times from one hour to
 one year.
     This model is a Gaussian plume model using diffusion coefficients
                    2
 suggested by Turner.   Concentrations are calculated for each hour
 of the year, from observations of wind direction in increments of
 17.45 milliradians (10 degrees), wind speed, mixing height, and
 atmospheric stability.  The atmospheric stability is derived by the
 Pasquill classification method as described by Turner.   In the
 application of this model, all pollutants are considered to be
 non-reactive and gaseous.
     Meteorological  data for 1964 are used as  input to the model.
The reasons for this  choice are:   (1) data from  earlier years
did not have sufficient resolution in the wind direction; and
(2) data after 1964 are available only for every third hour, where data
for 1964 are available on an hourly basis.
     Mixing height data are obtained from the twice-a-day  upper air
 observations made at the most representative upper air station.   Hourly
 mixing heights are estimated by the model using an objective  interpola-
 tion scheme.
                              F-7

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    A feature of this model is the modification of plume behavior to
account for aerodynamic effects for plants in which the design is-
not optimal.  Another important aspect of the model is the ability
to add concentrations from stacks located closely together.  In
this feature, no consideration is given to the physical separation between
the stacks since all are assumed to be.located at the same geographical
point.
    Calculations are made  for 180 receptors  (at 36 azimuths and five
selectable distances from  the source).  The model used can consider
both diurnal and seasonal  variations in the  source.  Separate
variation factors  can  be applied on a monthly  basis to account
for seasonal fluctuations  and on an hourly basis  to account for
diurnal variations/ Another "feature of "the"  mocisTis' the  ability
to compute frequency distributions for concentrations  of  any
averaging period over  the  course of a year.   Percentages  of various
 ranges in pollutant concentrations  are calculated.  One final
 feature of the single  source model  is  a  program which can add
 concentrations from two plants which  are not co-located but which
 do interact.

 F.6.   AERODYNAMIC-EFFECTS  MODIFICATION OF THE DISPERSION  MODEL
     The aerodynamic-effects modification of the dispersion model
 was  developed by the Source Receptor  Analysis Branch, Office" of
 Air Quality Planning and Standards, U.S.  Environmental Protection
 Agency, Research Triangle  Park, N.C.
                               F-8

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    The single source model does not address the aerodynamic com-
plications which arise when plant design is less than ideal.  These
effects result from the interaction of the wind with the physical
structure of the plant.  Such interaction can retard, or in the
extreme, prevent plume rise.  The extreme case is commonly referred
to as "downwash".  With downwash, the effluent is brought downward
into the wake of the plant, from which point it diffuses as though
emitted very close to the ground.  In the retardation case, some
of the dispersive benefits of plume rise are lost; while in the
downwash case, all of the benefits of plume rise are lost, along
with most of the benefits of stack elevation.  Both phenomena -
but especially downwash - can seriously increase the resulting ambient
air impact.
    The aerodynamic-effects modification then, is an attempt to include
these effects in a predictive model.  Basically, it enables the model
to make an hour-by-hour, stack-by-stack assessment of the extent
(:if any) pf_ aerodynamic complications.  The parameters used in
making the assessment are wind speed, stack-gas exit velocity,
stack height, stack diameter, and building height.  If a particular
assessment indicates no aerodynamic effect, then for that stack
(for that hour) the model behaves just as the unmodified version.
If there are aerodynamic effects, the modified version contains
equations by which the impact of these effects on ground-level
concentrations is estimated.
                             F-9

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F.7.  REFERENCES FOR APPENDIX F.
1.   Unpublished Data, Source Receptor Analysis  Branch, Office of
     Air Quality Planning and Standards,  U.S.  Environmental Pro-
     tection Agency, Research Triangle Park,  North  Carolina, June
     1975.
2.   Turner, D. B., "Workbook of Atmospheric  Dispersion Estimates",
     U.S. Dept. of H. E. W., PHS Publication  No. 999-AP-24 (Revised
     1970).
                            F-l8

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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT NO.
EPA-450/2-78-005a
2.
4. TITLE AND SUBTITLE
Electric Utility Steam Generating Units: B
Information for Proposed Nitrogen Oxides Em
Standards
7. AUTHOR(S)
3. RECIPIENT'S ACCESSIONING.
5. REPORT DATE
ackground July, 1978

ISSiOn 6- PERFORM1NG ORGANIZATION CODE
B. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Office of Air Quality Planning and Standard
Research Triangle Park, North Carolina 277
J2. SPONSORING AGENCY NArne AND AuOReSS
DAA for Air Quality Planning, and Standards
Office of Air and Waste Management
U.S. Environmental Protection Agency
Research Triangle Park. North Carolina 277
10. PROGRAM ELEMENT NO.
S 11. CONTRACT/GRANT NO.
11 . • ••-.-• •;/"•":/•"." '
, 13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY COOB
n ' EPA/200/04 ..''""
15. SUPPLEMENTARY NOTSS . •
Revised Standards of Performance for the control .of emissions of parti
sulfur dioxide from electric utility steam generating units are also t
These standards are supported in separate Background. Information docun
IPA-450/2-78-006a for particulates and EPA-450/2-78-007.a for sulfur. d'
culate matter and
>eing -'proposed.
nents, numbered
i oxide. .. .
16. Abstract
Revised Standards of Performance for the control of 'emissions' of nitrogen oxides
from electric utility power plants are being proposed under the authori-ty of -•
section 111 of the Clean Air Act. These standards would apply only to electric
utility steam generating units capable of combusting more than 73 MW heat input
(250 million B.tu) of fossil fuel and for which construction or modification began on
or after the date or proposal of the regulations. This document contains background
informations environmental and economic impact. assessments, and the rationale for
the standards, as proposed under 40 CFR Part 60, Subpart Da. ' . .
17.
KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Air pollution
Pollution control
Standards of performance
Electric utility power plants
Steam generating units
Nitrogen oxides
13. DISTRIBUTION STATEMENT
Unlimited
b.lDENTIFlERS/OPEN ENDED TERMS
Air Pollution Control
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COSAT! Field/Group

21. NO. OF PAGES
22. PRICH
EPA Form 2220-1 {9-73)

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