REVIEW  OF  NOx EMISSION FACTORS

   FOR  STATIONARY  COMBUSTION

     SOURCES AND AP-42  UPDATE



        R. J. Milligan, W. C. Sailor. J. Wasilewski and W. C. Kuby

                    Acurex Corporation
                Energy & Environmental Division
                    485 Clyde Avenue
                 Mountain View, California 94042



                       June 1979



            ACUREX FINAL REPORT  78-306
                       Prepared for
                 Task Officer:  Thomas Lahre


             Office of Air Quality Planning and Standards
                Environmental Protection Agency
                   Research Triangle Park
                    North Carolina 27711


                   Contract No. 68-02-2611
                       Task 34


                   Contract No. 68-01-4142
                       Task 23

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REVIEW OF NOx EMISSION  FACTORS
   FOR STATIONARY  COMBUSTION
     SOURCES AND AP-42 UPDATE


         R. J. Milligan, W. C. Sailor, J. Wasilewski and W. C. Kuby
                    Acurex Corporation
                 Energy & Environmental Division
                     485 Clyde Avenue
                 Mountain View, California 94042


                       June 1979


            ACUREX  FINAL REPORT 78-306
                       Prepared for
                  Task Officer: Thomas Lahre

             Office of Air Quality Planning and Standards
                Environmental Protection Agency
                    Research Triangle Park
                    North Carolina 27711

                    Contract No. 68-02-2611
                        Task 34

                    Contract No. 68-01-4142
                        Task 23

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                             TABLE OF CONTENTS


Section                                                                Page

   1      INTRODUCTION	'.	     1

   2      UTILITY BOILERS  	     4

          2.1  NOX Emission Factors for Utility Boilers  	     4
          2.2  Histograms of NOX Emissions for Utility Boilers ...     8
          2.3  Effect of Controls on NOX Emissions
               for Utility Boilers 	     8
          2.4  Nitric Oxide as Percent Constituent of
               Total  NOX Emissions	    13

   3      INDUSTRIAL  BOILERS 	    20

          3.1  NOX Emission Factors for Large Industrial Boilers .  .    20
          3.2  Histograms of NOX Emissions for Industrial Boilers.  .    23
          3.3  Nitric Oxide as Percent Constituent of
               Total  NOX Emissions	    23
          3.4  Effect of Controls on NOX Emissions for
               Industrial Boilers  	    28
          3.5  Other  Data	    28

   4      COMMERCIAL  AND RESIDENTIAL UNITS 	    32

                                                                        32

                                                                        35
                                                                        38

               and Residential Units . . . .	    38
          4.5  Nitric Oxide as Percent Constituent of Total
               NOX Emissions	    38

          STATIONARY  RECIPROCATING ENGINES 	    42

          5.1  NOX Emission Factors for Compression
               Ignition Engines  	    42
          5.2  NOX Emission Factors for Spark Ignition Engines ...    44
          5.3  Histograms of NOX Emissions for
               Reciprocating Engines 	    46
          5.4  Nitric Oxide as Percent Constituent of Total
               NOX Emissions	    46

          GAS TURBINES	    54

          6.1  NOX Emission Factors for Various Types and Sizes
               of Gas Turbine Engines	    54
                                    m
4.
4.

4.
4.
1
2

3
4
NOX
NOX
and
NOX
His1
Emission
Emission
Boi 1 ers
Emission
:ograms of
Factors
Factors

Factors
NOX Emi
for
for

for
Commercial Sized Boilers . .
Residential Furnaces

Pilot Lights 	

ssions for Commercial

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                       TABLE OF CONTENTS (Concluded)

Section                                                                Page

          6.2  Histograms of NOX Emissions for Gas
               Turbine Engines	       54
          6.3  State-of-the-Art Control Techniques for NOX
               Emissions — Water Injection	       58
          6.4  Nitric Oxide as Percent Constituent of
               Total NOX Emissions	       58
                                     iv

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                           LIST OF  ILLUSTRATIONS
Figure                                                                Page

  2-1     Population  Histograms  of NOX Emission Factors for
          Horizontally Opposed Utility Boilers  	     9

  2-2     Population  Histograms  of NOX Emission Factors
          for  Single  Wall  Utility Boilers   	    10

  2-3     Population  Histograms  of NOX Emission Factors
          for  Cyclone Utility Boilers  	    11

  2-4     Population  Histograms  of NOX Emission Factors
          for  Bituminous  Coal-Fired Tangential  Utility Boilers  ...    12

  3-1     Population  Histograms  of NOX Emission Factors
          for  Industrial  Boilers 	    24

  4-1     Population  Histograms  of NOX Emission Factors
          for  Natural Gas-Fired  Commercial  Boilers, Residential
          Units,  and  Pilot Lights  	    39

  5-1     Population  Histograms  of NOX Emission Factors
          for  Compression Ignition Engines  Firing Diesel Fuel   ...    47

  5-2     Population  Histograms  of NOX Emission Factors
          for  Compression Ignition Engines  Firing Dual Fuels  ....    49

  5-3     Population  Histograms  of NOX Emission Factors
          for  Stationary  Reciprocating,  Natural Gas Firing
          SI Engines	    50

  5-4     Population  Histograms  of NOX Emission Factors
          for  Stationary  Reciprocating Gasoline Fired
          Spark Ignition  Engines	    51

  6-1     Population  Histograms  of NOX Emission Factors
          for  Gas Turbine Engines	    56

  6-2     Effectiveness  of Water/Steam Injection  in Reducing
          NOX  Emissions	    59

  6-3     NO and  N02  Concentrations  at the  Base of No. 3 Stack
          for  Various Turbine Loads,  i.e.,  Turbine Inlet Temperature
          (Reference  6-7)  	    60

  6-4     NO and  NOX  Concentrations  of a Small  Turbine at Various
          Loads Firing No.  2 Oil	    61

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                               LIST OF TABLES


Table                                                                  Page

  1-1     Conversion Factors	      3

  2-1     NOX Emission Factors Survey of Utility Boilers
          (English Units)  	      5

  2-2     NOX Emission Factors Survey of Utility Boilers
          (SI Units)	      6

  2-3     Average Percent Reduction of NOX Emission Factors
          by State-of-the-Art Control Techiques for Utility Boilers
          (English Units)  	     14

  2-4     Nitric Oxide as a Constituent of Total NOX Emissions
          of Utility Boilers	     16

  3-1     NOX Emission Factors Survey of Industrial Boilers
          (10 to 100 x 106 Btu/hr) (English Units)	     21

  3-2     NOX Emission Factors Survey of Industrial Boilers
          (2.9 to 29 MW) (SI Units)	     22

  3-3     Nitric Oxide as a Constituent of Total NOX Emissions
          of Industrial Boilers	     27

  3-4     Comparison of Data from Ferrari et al. with Calculated
          Averages for Same Boiler Type and Size	     29

  4-1     NOX Emission Factors Survey of Commercial Stationary
          Steam and Hot Water Generating Units
          (0.5 to 10 x 106 Btu/hr) (English Units)	     33

  4-2     NOX Emission Factors Survey of Commercial Stationary
          Steam and Hot Water Generating Units
          (0.5 to 10 x 106 Btu/hr) (English Units)	     34

  4-3     NOX Emission Factors Survey of Residential Steam
          and Hot Water Generating Units (<500,000 Btu/hr)
          (English Units)  	     36

  4-4     NOX Emission Factors Survey of Residential Steam
          and Hot Water Generating Units (<0.15 MW) (SI Units) ...     37

  4-5     Nitric Oxide as a Constituent of Total NOX Emissions
          of Commercial and Residential Boilers and Heating Units
          and Pilot Lights	     40

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                         LIST OF TABLES (Concluded)


Table                                                                  Page

  5-1     Baseline NOX Emission Factors Survey of Reciprocating
          Compression Ignition (CI)  Engines  	    43

  5-2     Heat Rates for Compression Ignition Engines  	    44

  5-3     NOX Emission Factors Survey of Reciprocating
          Spark Ignition (SI) Engines	    45

  5-4     Nitric Oxide as a Constituent of Total NOX Emissions
          of Reciprocating Engines 	    52

  6-1     NOX Emission Factors Survey of Simple and Regenerative
          Cycle Gas Turbines	    55

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                                 SECTION 1
                                INTRODUCTION
       In order for EPA, states, and local agenices to compile reliable
emission inventories of nitrogen oxides, it is important to have accurate
and precise NO  emission factors.   The two major source categories
              A
responsible for the bulk of all  manmade NO  emissions are mobile sources
                                          A
and stationary source combustion.   The Monitoring and Data Analysis
Division (MDAD) of The Office of Air Quality Planning and Standards is
responsible for determining the  NO  emission factors for the latter
                                  s\
area.   Hence, it is periodically necessary that MDAD critically review
the existing emission factors for the major stationary sources of NO
                                                                    X
and update those factors for which newer and more comprehensive data exist.
       To assist MDAD in this task, The Energy and Environmental Division
of Acurex has compiled and reviewed the NO  source test data that have
                                          X
been generated over the last several years on the major stationary
combustion sources.  This compilation includes external combustion of
coals, oils and gas in boilers as well as internal combustion in
reciprocating and turbine engines.
       Stationary external combustion units are covered in the next three
sections of this report.  For the purposes of this report, they are broken
into four categories:
       t   Utility boilers — >29 MW (>100 x 106 Btu/hr) input
       •   Industrial boilers — 2.9 to 29 MW (10 to 100 x 106 Btu/hr)
           input
       •   Commercial boilers — 150 kW to 2.9 MW (5 x 105 to 10 x
           106 Btu/yr) input
       •   Residential furnaces  and boilers -- <150 kw (<5 x 10  Btu/yr)
           input

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Within each size category, the boilers  are further  classified  according  to
design and fuel.  Section 2  is devoted  to utility boilers  alone.
Section 3 covers industrial  boilers  and Section 4,  commercial  and
residential units.   In  support of the NO  emission  factor  tables,  each
                                         /\
section also contains population-NO  emission  histograms,  percentage  NO
                                   ^
in NO  and, for utility boilers, a section on  state-of-the-art control
     /\
techniques and their effectiveness.
       The last two  sections cover stationary  reciprocating  engines and
turbines, respectively.  The breakdown  within  each  section is  based on
size, number of strokes  per  combustion  cycle and fuel for  reciprocating
engines and size, type  of cycle  and  fuel for turbines.
       In assessing  the  data reviewed in this  study,  it  was  mandatory that
the following information, in addition  to that needed to calculate the
NO  emission factors, be known:
  J\
       •   The type  of  boiler or engine -- e.g., tangential, four  stroke
       t   Boiler operating  condition:   "baseline"/state-of-the-art NO
                                                                      /\
           control techniques -- This was particularly  important for
           utility sized boilers and turbines; all  other sources had  no
           NO  control  technique applied unless they were  specifically
             ^
           operated  under a  control  evaluation program.
       This report is concerned  with emissions at the "baseline,"  or
as-found condition.  Thus, baseline  emissions  are those  measured generally
in the absence of any NO control techniques.  For  utility and
                         A
industrial boilers,  baseline measurements were included  if they were  made
at 60 to 110 percent load.   All  data reported  without the  type of  boiler
delineated were rejected; data reported on utility  boilers,  turbines, etc.
with NO  control techniques  specified e.g., BOOS, FGR, water injection,
       A
etc. were included in the section on control effectiveness.
       Table 1-1 includes thermal equivalents  for fuels  discussed  in  this
report.  Since the emission  factor tables are  expressed  both in terms of
Ib/fuel unit and ng/J,  these factors were used for  conversions when the
data was reported in only one set of units.

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                     TABLE 1-1.   CONVERSION FACTORS
To Obtain
From
Multiply By
  ng/J
  ng/J NOX (as N02)
  ng/J NOX (as N02)
  ng/J NOX (as N02)
  NOX ppm @ 3% 02 dry
lb/106 Btu
NOX ppm @ 3% 02 dry
NOX ppm @ 3% 02 dry
NOX ppm @ 3% 02 dry
NOX ppm dry
430
  0.510 (natural gas)*
  0.561 (oil)*
  0.611 (coal)*
 /      17.9
 \20.9 - % 02 dry
                            Thermal  Equivalents*
                   Fuel
            Bituminous coal
            Lignite coal
            Residual oil
            Distillate oil
            Natural gas
             Heating Value (Gross)
            10,000 - 14,000 Btu/lb*
            (used 12,000 Btu/lb)
                      8,000 Btu/lb*
                    150,000 Btu/gal*
                    140,500 Btu/gal*
                      1,050 Btu/ft3
*These factors used only when data were otherwise insufficient.
Sources:
Maloney, K. L., et al.,  "systems Evaluation of the Use of Low-Sulfur Western
Coal in Existing Small  and Intermediate-Sized Boilers," KVB Inc.,
EPA-600/7-78-153a, July 1978.
U.S. Environmental Protection Agency, "Compilation of Air Pollutant Emission
Factors," Third Edition, AP-42, August 1977.

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                                  SECTION 2
                              UTILITY BOILERS


       For the purposes  of this  study, utility boilers  are defined  as
field-erected watertube  boilers  with a heat  input greater than 29 MW
(100 x 10  Btu/hr) used  for generation of electricity.  This category
includes the vast majority of field-erected  boilers used for utility or
industrial electric power generation via steam production.  The major
fuels fired are coal, oil, and natural gas.  Within this definition, the
utility boiler population is divided into nine major boiler types and
further subdivided into  seven fuel categories.  Firing  of subbituminous
coal is included  in the  bituminous category.
2.1    NOX EMISSION FACTORS FOR  UTILITY BOILERS
       Tables 2-1 and 2-2 contain the NO  emission factors for utility
                                        /\
boilers.*  The first table is in English units and the  emission factors
are based on the  amount  of fuel  consumed.  The second table is in SI units
and the emission  factors  are given as weight per energy unit released
lng/J).
       A considerable body of data were collected for horizontally  opposea
units firing bituminous  coal, oil and natural gas.  These data were
abstracted from several  different sources (References 2-1, 2-2, 2-3, 2-4,
2-5, 2-6 and 2-7).  Major differences between the new averages and  the
existing AP-42 values occur in the oil- and  the bituminous coal-fired
units.  In the former, the NO  average emission factor  was 35 percent
                             A
lower and in the  latter  50 percent higher.   Because of  the number of data
*The factors reported  in  the  tables  as well  as  the  text  are  in  terms  of
 NOX emissions as N02  except  as  noted.

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TABLE  2-1.   N0v  EMISSION FACTORS  SURVEY  OF UTILITY  BOILERS  (ENGLISH  UNITS)
                   A
Type
Boiler
Tangential
Horizontally
Opposed
Single Wall
Vertical1"
Cyc 1 one
Wet
Bottom'
Spreader
Stoker
Overfeed
Stoker
Baseline NOX Emissions as a Function of Fuel3
Coal {lb/ton burned)
Anthracite



18




Bituminous
18b
14C (27<1)
-22X6
18
27 (8)
+50X
18
20 (11)
+ux
18
55
36 (7)
-35X
30
48 (2)
+60X
15
15 (8)
OX
5.4 (2)
Lignite
8
7 (2)
-12t
14
14
13 (1)
-7X
14
17
12 (3)
-29X
14


Oil (lb/103 Gal oil burned)
Residual
50
42 (2)
-16X
105
68 (9)
-35X
105
65 (36)
-38X
105
105
87 (4)
-17X



Distillate


28 (3)





Gas (lb/106 SCF gas)
Natural
300
200 (3)
-33X
700
570 (10)
-19X
700
340 (39)
-51X
700
700
660 (2)
-6X



Process


790 (8)





  aNOx  values  reported in terms of NO^
  b01d  AP-42 value
  GRecommended replacement number based on new or revised data base
   Number of boilers  tested
  ePercent change in  emissions factor
   Includes one vertical and one horizontally-opposed unit
EE-T-118

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 TABLE  2-2.   NOX  EMISSION  FACTORS SURVEY  OF  UTILITY  BOILERS (SI  UNITS)
Type
3oiler
Tangential
Horizontally
Opposed
Single Wall
Vertical6
Cyc 1 one
wet
3ottomr
Soreader
Stoker
Overfeed
Stoker
Baseline NOX Emissions (ng/J) as a Function of Fuel4
Coal
Anthracite



310




Bituminous
320b
250"= (27
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points and the variety of sources, the new numbers appear to be more
justifiable than the old.
       Data were also obtained for tangential units firing bituminous coal
(References 2-8, 2-1, 2-2, 2-9, 2-10, 2-11, 2-12, 2-13, and 2-14).  The
NO  emission factor obtained from averaging these baseline test numbers
was 22 percent less than the existing AP-42 value.
       A considerable body of data were also obtained for single wall
units firing bituminous coal (References 2-8, 2-2, 2-6, 2-11 through 2-17,
2-18, 2-19, 2-20, and 2-13], oil (References 2-1, 2-2 and 2-15), natural
gas (References 2-1, 2-3, 2-4, 2-5 and 2-15) and process gas (Reference
2-16).  All NO  emission factors were less than those given in AP-42
              A
except for bituminous coal which showed a slight increase.  The decreases
for the oil-fired units (38 percent) and the gas-fired units (51 percent)
give values consistent with expected results when these units are compared
with horizontally opposed units and single wall, large industrial boilers
burning the same fuels.  Consistent with the other average values obtained
for single wall and horizontally opposed boilers, it is recommended that
the average value for lignite-fired, single wall boilers be reduced from
14 Ib/ton (380 ng/J) to 13 Ib/ton (350 ng/J).  The eight process gas-fired
utility boilers show an average NO  emission factor of 790 lb/10  scf
                                  A
(330 ng/J).
       All of the cyclone boiler data came from a recent compilation of
previous tests (Reference 2-21).  These data show less NO  emission than
                                                         s\
the initial AP-42 numbers in all fuel categories.  In particular, NO
                                                                    A
emissions for bituminous coal-fired cyclone boilers were 34 percent less
than the initial AP-42 value.  The new data are probably more accurate as
they are based on the average of seven different cyclone boilers.  Some
cyclone boilers may have been better classified as large industrial units
but were included in the utility section to provide a better data base.
       No new data were obtained for vertical units and only two new data
points were obtained for wet bottom units.  Both of these were in the
bituminous coal category (References 2-8 and 2-1).  These data suggest
that wet bottom, coal-fired boilers should have their NO  emission
                                                        A
factors increased by some 60 percent.  In comparison to cyclone units, the
original wet bottom boiler NO  emission data seem unusually low; the new
                             /\

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data, especially in  light of  the recent cyclone  boiler  data, would  seem
more reasonable for  such units.
       The remaining category for which new  information  is  now  available
is for spreader stoker units  firing bituminous coal.  New data  on six
units are included (References 2-15, 2-16, 2-22, 2-23,  2-24, and 2-25).
The average NO  emission value, 15  Ib/ton  (270 ng/J)  is  a good
representative value for these units, agreeing well with the industrial
boiler NO  emission  factor for the  same category.
         /\
       Although wet  bottom boilers  are not mutually exclusive from  the
other categories, in this report they are  treated  separately because of
their very high NO   emission  rates.
2.2    HISTOGRAMS OF N0y EMISSIONS  FOR UTILITY BOILERS
                       ^\
       Figures 2-1,  2-2, 2-3  and 2-4 are bar graphs of  baseline NO
                                                                  J\
emission factors versus number of units tested within each  boiler
type/fuel category.  Figure 2-1 covers bituminous  coal-, oil- and
gas-fired horizontally opposed units; Figure 2-2 covers  bituminous  coal-,
oil- and gas-fired single wall units.  Figure 2-3  covers bituminous coal-
and oil-fired cyclone units and Figure 2-4 covers  bituminous coal-fired
tangential units.  Since there were only two data  points for natural
gas-fired cyclone units, no histogram was  constructed.   With few
exceptions, the data fall quite close together considering  the  numbers of
variables involved.  Two boilers, one a gas-fired, single wall  unit and
the other an oil-fired, single wall unit,  were too far  from the average
based on Chauvenet's criterion and, were excluded  from  the  data presented
in Tables 2-1 and 2-2.
       The variation within each boiler and  fuel category may be due to
load (not all baselines were  run at 80 percent load), air preheat,  burner
type, furnace dimensions, differences in fuel nitrogen,  amount  of excess
air, errors in measurement, to name a few.   Because of  the  number of
variables, the data  are presented to only  two significant figures.
2.3    EFFECT OF CONTROLS ON  NO  EMISSIONS FOR UTILITY  BOILERS
       There are several NO   control techniques  currently in use with
                           /\
utility boilers.  These include:
       •   Low Excess Air (LEA) --  The excess amount  of  combustion  air
           supplied  is reduced

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0
Avt'rauo
. WMM 1 iW/l m
lAn 1 J V 1 1 1 1 1
IOU 200 300 400 500 600 700 800
\ ^\ m
900 1150
	 —*. — 	
                       (80)
                                        NO.
                                  (160)                 (240)


                                          fdo.ors. In/ 10° scf (no/,))
                                    a.  Natural Gas-Fired Horizontally Opposed Boilei
                                     Average
                                       70
                                                            90
                 (MO)
(200)
(260)
      N0x emission factors,  lb/10 qal (ng/J)

  b.   Residual Oil-Fired Horizontally Opposed Boilers
                                                   Average
           ~r
          (260)


emission factor-.  In/ton  (ny/,1)
                                            (440)
                                (620)
                                               (320)
                                               (480)
m m m \m
10
Ib
m m
20 25 30 35
m
40 4!i
                                     (800)
  i.  Biliniiinoiis Coal-: in."! llurizontal ly Opposed Boilers


Figure 2-1.   Population  histograms  of  NOX  emission  factors  for  horizontally opposed
                 utility  boilers.

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12 _
11 _
10 —
9 -
8 _
7 _
6 -
5 -
4 _

1 _
11 -n
10
5 MILJ
fi
-.

5 —
4 _
2 -
5 -,
4 _
3 -
2 -
1 -
_ A'
f/i '
mm
Wh
w, u*
M M.
22
W&
LL a*
££
'ft jd/
. W/W/A
erage
m
///
72
E
u.
77,
%
// i

/// -__t , „ ,
Y/. m w.
V
•
t
wm . n
v r T i i i iv! i
200 300 400 500 600 700 800 1200 1300
A A
^ 1 i i V i
(80) (180) (280) <£30;
N0x emission factors lb/10 scf (ng/J)
a. Natural Gas-Fired Single Wall Boilers
Ayorxno //,

n
%
Tfr
'//
"77, 7?/
WM> ' w.
Tl/tf/JT/jj.
wttM/,
WutfLMt.
m Tmv/y/,
'//<
'//<
//,
'//
7,

'//<
}),
Y/
W<
25 50 7
A
"V |
'. 70 :
N0x emission factor
b. Residual Oil -Fired
Avei
•
VA U^ M Wk
10 15 2
A
(22
s,
Sin
•ag<

J '{
% \
yg r-, *
W/. R
1 1
5 100 125
f
>0) !370'
lb/103 gal (ng/J)
gle Wall Boilers
* r
-
mm m
i i i
0 25 30 35
v 1 1 1
(270) (450'.
   c.
                       N0x (Mission factors, Ib/ton (ng/J)

                       Bituminous Coal-Fired Single Wall Boilers
        •after a statistical analysis these tests were not considered reoreser.ta'.i
         tne boiler oooulation,  and therefore not included in  tne replacement emis
         factor.
Fiqure  2-2.
Population histograms of NOX emission  factors
for single wall  utility  boilers.
                                    10

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4 -.
3 -
2-
1 -
Average


m m


m
VI i I |
70 80 90 100
-A, .



m
i
no
(200)
                   (230)
(260)
(290)
(320)
3 -
               NO  emission  factors,  lb/10  gal  (ng/J)
               a.   Oil-Fired  Cyclone Boilers

                      Average
. F
V
A
V
T\ 1 ra ,

t////x
30 35 40
1 I
(540) (720)

I I
45 50
1
(900)
VA


               NO  emission factors,  Ib/ton (ng/J)

               b.  Bituminous  Coal-Fired Cyclone  Boilers
      Figure 2-3.
                           Population  histograms  of NOX emission
                           factors for cyclone utility  boilers.
                                   11

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          GJ
      5  -
      4  -
             3  -
          I  2
          I  1
                                 Average
                         Wm
                                     15
                                             20
                    (180)
                            (270)
(360)
                  NO  emission factors,  "ib/ton (ng/J)
     Figure 2-4.  Population histograms of NOX emission factors for
                  bituminous coal-fired tangential utility boilers.
           Off-Stoichiometric Combustion (OSC) -- Some burners fire a
           fuel-rich mixture and combustion is completed by injection of
           additional air or lean mixture downstream
           Flue Gas Recirculation (FGR) -- A portion of the flue gas is
           recycled to the firebox
           Load Reduction (LR) -- The boiler is fired at less than capacity
           Combinations of two or more of the above
•
•
t
           Low NO  Burner (LNB)
                 /\
       Much of the data on these controls have previously been analyzed by
Acurex (Reference 2-26).  In addition to this review, a section of the
cyclone boiler report (Reference 2-21) considers the applicability of many
NO  control techniques to this boiler type.  The Standards Support and
  A
Environmental Impact Statement report on lignite-fired boilers
(Reference 2-27) also dwells on certain of the N0x controls.  Table 2-3
indicates the percent reduction one can expect by applying particular
NO  control techniques to each boiler/fuel category.
                                     12

-------
   TABLE  2-3.' AVERAGE  PERCENT REDUCTION  OF NOX  EMISSION FACTORS  BY STATE-OF-THE-ART
                 CONTROL  TECHNIQUES  FOR UTILITY  BOILERS  (ENGLISH UNITS)

Type Boiler
Control
Techniques
Tangential
Baseline
LEA
OSC
FGR
LR
OSC + FGR
OSC + LR
OSC + LR + FGR
Horizontally
Opposed
Baseline
LEA
OSC
FGR
LR
OSC + FGR
OSC + IR
OSC + LR + FGR
LNB
NO Emissions (16 NO^/unit fuel consumed) as a Function of Fuel
Coal
Bituminous
NOX (Ib/ton)

15
12
9

13

8


25
22
20
20
22
15
19

15
% Reduction

—
20
40
*
15
*
45
*


—
10
20
20
10
40
25
*
40
Lignite
NOX { lb/ ton)

8
6
5

7

4


14
11
11
11
13
[8]
10


% Reduction

—
20
38
*
12
*
45
*


—
20
20-
20
10
[40]
25
*




Residual 01 1
NOX (lb/103 gal)

50
401
[40
35;
45
20
35'
35;


70
56
45
60
50
56
35
28




















% Reduction

—
[20
[20
[30
[10
[60
[30
[30.


—
20
35
13
30
20
50
60





















Natural Gas
NOX (lb/106 SCF)

300
210
300
120
300
[90]
[270]
[60]


700
600
300
[350]
300
[175]
140
100

(I Reduction)

--
30
0
60
0
[70]
ho
170]


—
15
60
[60]
60
[75]
80
85

'Indicates that no data Is available and technique may result In severe corrosion and/or slagging problems
[  ] Indicates engineering estimate

-------
                                                 TABLE  2-3.   Concluded

Type Boiler
Control
Techniques
Single Mall
Baseline
LEA
OSC
FGR
LR
OSC + FGR
OSC * LR
LR + OSC + FGR
LNB
Cyclone
Baseline
LEA
OSC
FGR
LR
OSC + FGR
OSC t LR
OSC + LR + FGR
NO Emissions (Ib NO^/unlt fuel consumed) as a Function of Fuel
Coats
Bituminous
N0x (Ib/ ton)

19
16
13

14

10

11

36



25



% Reduction

--
IS
30
4
25
*
45
*
40

—
*
*
•
30
*
*
*
Lignite
NO (Ib/ton)

["]
CJ

[81

[6]



13



9



% Reduction

--
[20]
[30]
*
[25]
*
[45]
*


_-


4
3



Residual Oil

N0x (lb/103 gal)

50
31)
30
[35]
35
22
2B
22


87
78

[61]
70



% Reduction

_-
25
40
[30]
30
55
45
55


--
10
*
[30]
20
*
*
*
Natural Gas

N0x (lb/106 SCF)

410
350
210
270
125
105
80
165


660
[560]

330
[330]



(% Reduction)

__
15
50
35
70
75
80
60


..
[15]
*
50
[50]
*
*
*
•Indicates that no data  is available and technique may result  in severe corrosion and/or slagging problems
[ ] Indicates engineering estimate

-------
       It should be noted that off-stoichiometric combustion (OSC), also
known as two-staged combustion, can be accomplished by one of the
following:
       •   Burners-Out-Of-Service (BOOS) -- Lower burners fire a fuel-rich
          .mixture, while upper burners supply only combustion air
       §   Biased Burner Firing (BBF) -- Lower burners simply fire a
           richer fuel-air mixture than upper burners
       t   Overfire Air (OFA) -- All burners fire a richer mixture, then
           additional combustion air is supplied above the firebox
The first two are generally used in a retrofit situation while the last is
principally a new boiler feature.
2.4    NITRIC OXIDE AS PERCENT CONSTITUENT OF TOTAL N0v EMISSIONS
                                                      A
       Some data, principally from KVB (Reference 2-10 and 2-11) and the
cyclone boiler report (Reference 2-21) indicate that NO is the principal
constituent of NO .  Of the four boiler categories for which either NO
                 A
or N0? were measured along with NO , NO constituted at least 95 percent
     L.                            A
of the NO  emissions.  These data are presented in Table 2-4.
         A
     TABLE 2-4.   NITRIC OXIDE AS A CONSTITUENT OF TOTAL NOX EMISSIONS
                 OF UTILITY BOILERS
Type
Boiler
Single wal 1
Cyclone
NO/NOX as a Function of Fuel3
Bituminous
Coal
96% (3)b
99% (6)
Residual
Oil
98% (1)

Natural
Gas
95% (2)

       aWeight percentage, NO reported as N02
       ^Numbers in parentheses refers to number of boilers tested.
                                     15

-------
                          REFERENCES FOR SECTION 2
2-1,   Bartok, W., et al., "Systematic Study of NOX Emission Control Methods
       for Utility Boilers," Exxon Report, GRU-4GNOS-71, December 1971.

2-2.   Crawford, A. R.,  et al., "Field Testing:  Application of Combustion
       Modifications to  Control NOX Emissions from Utility Boilers,"
       EPA-650/2-74-066,  NTIS-PB 237 344/AS, June 1974.

2-3.   Dykema, 0. W., "Analysis of Test Data for NOX Control in Gas and
       Oil-Fired Utility Boilers," EPA-650/2-75-012, NTIS-PB 241 918/AS,
       January 1975.

2-4.   Dykema, 0. W. and  R. E. Hall, "Analysis of Gas-, Oil, and Coal-Fired
       Utility Boiler Test Data," in Proceedings of the Stationary Source
       Combustion Symposium, Volume III, EPA-600/2-76-152c, NTIS-PB 257
       I46/AS, June 1976.

2-5.   Bartz, D. R., et  al., "Control of Oxides of Nitrogen from Stationary
       Sources in the South Coast Air Basin," ARB 2-1471 (KVB Report No.
       5800-179), September 1974.

2-6.   Crawford, A. R.,  et al., "Field Testing:  Application of Combustion
       Modification to Power Generating Combustion Sources," Proceedings of
       the Second Stationary Source Combustion Symposium, Volume II, Utility
       and Large Industrial Boilers, EPA 600/7-77-073b, July 1977.

2-7.   Thompson, R. E.,  et al., "Effectiveness of Gas Recirculation and Staged
       Combustion in Reducing NOX on a 560 MW Coal-Fired Boiler," EPRI
       Report No. FP-257, NTIS-PB 260 582, September 1976.

2-8.   Crawford, A. R.,  et al., "Control of Utility Boiler and Gas Turbine
       Pollutant Emissions by Combustion Modification — Phase I,"
       EPA-600/7-78-036a, March 1978.

2-9.   Blakeslee, C. E.,  and A. P. Selker, Program for Reduction of NOX from
       Tangential Coal-Fired Boilers, EPA-650/2-73-005, 5a and 5b, NTIS-PB 226
       547/AS, PB 245 162/AS, PB 246 889/AS, August 1973, .June 1975 and August
       1975.

2-10.  Burrington, R. L., et al., "Overfire Air Technology for
       Tangentially-Fired Utility Boilers Burning Western U.S. Coal,"
       EPA-600/7-77-117,  NTIS-PB 277 012/AS, October 1977.

2-11.  Hollinden, G. H.,  et al., "NOX Control at TVA Coal-Fired Steam
       Plants," ASME Air  Pollution Control Division, in Proceedings of the
       Third National Symposium, April 1973.
                                     16

-------
2-12.   Higginbotham,  E.  B.  and P.  M.  Goldberg,  "Field Testing of a Tangential
       Coal-fired Utility Boiler -- Effects of  Combustion Modification NOX
       Control  on Multimedia Emissions,"  Acurex Draft Final Report 79-337,
       April  1979.

2-13.   Crawford,  A.  R.,  £t aK_,  "NOX  Emission Control for Coal-Fired Utility
       Boilers,"  Esso Research and Engineering  Company.  Paper presented at
       the Coal  Combustion Seminar, Research Triangle Park, North Carolina,
       June 19-20, 1973.

2-14.   Crawford,  A.  R.,  £t ^1_._,  "The  Effects of Combustion Modification on
       Pollutants and Equipment Performance of  Power Generation Equipment,"
       Proceedings of the Stationary Source Combustion Symposium, Volume III,
nary b
,  EPA-
       Field Testing and Surveys,  EPA-600/2-76-152c, June 1976.

2-15.  Cato, G. A.,  et al.,  "Field Testing:   Application of Combustion
       Modifications to Control  Pollution Emissions from Industrial Boilers --
       Phase I," EPA-650/2-74-078a, NTIS-PB  238 920/AS, October 1974.

2-16.  Cato, G. A.,  et al.,  "Field Testing:   Application of Combustion
       Modifications to Control  Pollution Emissions from Industrial Boilers --
       Phase II," EPA-600/2-76-086a, NTIS-PB 253 500/AS, April 1976.
2-17.  Hollinden, G.  H.,  et _a]_._,  "Control  of NOX Formation in Wall
       Coal-Fired Boilers,  in Proceedings  of the Stationary Source Combustion
       Symposium, Volume  II, EPA-600/2-76-152b, NTIS-PB 256 321/AS, June 1976.
2-18.  Hunter, S.  C.  and H.  J.  Buening, "Field Testing:   Application of
       Combustion  Modifications to Control  Pollutant Emissions from Industrial
       Boilers —  Phase I and II (Data Supplement)," EPA-600/2-77-122, June
       1977.

2-19.  U.S. Environmental Protection Agency, "Supplement No. 6 for Compilation
       of Air Pollutant Emission Factors,"  Office of Air Quality Planning and
       Standards,  AP-42, April  1976.

2-20.  Maloney, K. J.,  "Western Coal Use in Industrial  Boilers," Western
       States Section/The Combustion Institute, Salt Lake City, Utah,
       April 1976.

2-21.  Ctvrtnicek, T.  E. and S. J. Rusek, "Applicability of NOX Combustion
       Modifications  to Cyclone Boilers (Furnaces)," EPA-600/7-77-006, January
       1977.

2-22.  Unpublished Data, EPA 68-02-2160, Acurex Corporation, August 1978.

2-23.  Maloney, K. L.,  et al.,  "Systems Evaluation of the Use of Low-Sulfur
       Western Coal in  "Existing Small and Intermediate-Sized Boilers,"
       KVB Inc., EPA-600/7-78-153a, July 1978.

2-24.  Gabrielson, J.  E., £t jil_._, "Field Tests of Industrial Stoker Coal-Fired
       Boilers for Emissions Control and Efficiency Improvement - Site A,"
       KVB Inc., EPA-600/7-78-136a, July 1978.


                                     17

-------
2-25.  Gabrielson, J. E.. et al., "Field Tests of  Industrial Stoker
       Coal-Fired Boilers for Emissions Control and Efficiency Improvemer
       - Site 3," KVB Inc., EPA-600/7-79-04ia, February 1979.

2-26.  Lim, K. J., et al., "Environmental Assessment of Utility Boiler
       Combustion Modification NOX Controls," Acurex Draft Report
       TR-78-105, April 1978.

2-27.  Goodwin, D. R.,  "Standards Support and Environmental  Impact
       Statement, Volume  I:  Proposed Standards of Performance for
       Lignite-Fired Steam Generators," EPA-450/2-76-030a, December 1976.
                                     18

-------
                                 SECTION 3
                             INDUSTRIAL BOILERS


       Industrial boilers, for the purposes of this study, are defined as
coal-, oil-, or gas-fired steam generators with rated heat input
capacities ranging from 2.9 to 29 MW (10 to 100 x 106 Btu/hr).  These
units are generally packaged boilers, including small, stoker, coal-fired
units as well as oil (residual and distillate) or gas burning firetube and
watertube boilers.  As in Section 2, subbituminous coal is included in the
bituminous category.
       As with all general definitions, there are exceptions.  In fact,
nearly 14 percent of the industrial boiler population have input
capacities greater than 73 MW and nearly 26 percent have  input capacities
smaller than 2.9 MW (Reference 3-1).  For purposes of this report those
industrial boilers which have rated heat input capacities greater then
29 MW were incorporated with the previous utility boiler  review, and those
of less than 2.9 MW were designated as residential-commercial types,
Section 4.
3.1    NOY EMISSION FACTORS FOR INDUSTRIAL BOILERS
         /\
       Industrial boilers burning oil and natural gas have been divided
into two boiler types, watertube and firetube.  A considerable quantity of
data — much of it from the KVB reports — were amassed for each category
(Tables 3-1 and 3-2).   As before, Table 3-1 is presented  in English units
and Table 3-2 contains the same data presented in SI units.  Since
existing AP-42 emission factors for natural gas combustion are expressed
as a range, suggested replacement factors are expressed in the same
manner.  Besides these results, the data also include Ultrasystems data
for a watertube and a firetube boiler tested with both natural gas and
residual oil (References 3-2 and 3-3) and Battelle data for a watertube
                                     19

-------
         TABLE  3-i.   NOX  EMISSION  FACTORS SURVEY  OF  INDUSTRIAL  BOILERS
                        {10  to  100 x  106  Btu/hr) (ENGLISH UNITS)
                                   Baseline NOv Emissions  as a Function of Fuel3
Type
Boiler
Water-tube
Firetube
Spreader
Stoker7"
[
i
Underfeed
Stoker^

1
Coal (Ib/ton burned) Oil (Ib/I03 gal)
!
Anthracite




Overfeed ! 16
j Stoker^ !
Bituminous


15
14 (3)
75!
15
9.5 (4)
-375!
15
7.8 (3)
-505!
Lignite


6.0
9 h
6.0
6.0
Residual
60t>
6QC (14)d
0X9
60
37 (6)
-38%



Distillate
22
19 (5)
-14%
22
21 (7)
-4%



Natural Gai; i
(lb/106 SC-) '
120-230
150 (13)
70-3106
120-230
110 (9)
65-150



 N0x values reported  in terms of NO.  -
b01d AP-42 value
""Recommended replacement numoer based on new or  revised data  base
 Number of boilers  tested
eRange found for boilers tested
 Stokers may be of  either watertube or firetube  construction
^Percent change in  emission factor
 [ ] Engineering estimate
EE-T-120
                                              20

-------
          TABLE 3-2.   NOX  EMISSION  FACTORS SURVEY  OF  INDUSTRIAL  BOILERS
                         (2.9 to 29 MW)  (SI  UNITS)
Type
Boiler
Water-tube
Firetube
Spreader
Stoker^
Underfeed
Stoker^
Overfeed
Stoker^
Baseline NOX Emissions (ng/J) as a Function of Fuel3
Coal
Anthracite




270
Bituminous


270
250 (3)
7%
270
170 (4)
-37%
270
140 (3)
-50%
Lignite


160
240 h
160
160
Oil
Residual
170b
170C (14)d
-6X9
170
110 (6)
-35X



Distillate
67
58 (5)
-18*
67
64 (7)
-3*



Natural Gas
49-94
60 (13)
30-1306
49-94
45 (9)
28-60



 NO  values reported in terms of  NO-
b01d AP-42 value
cRecommended replacement number based on new or  revised data base
 Number of boilers  tested
eRange found for boilers tested
 Stokers may be of  either watertube or firetube  construction
^Percent change in  emission factor
 [ ] Engineering estimate
EE-T-121
                                                21

-------
ana firetube boiler tested with  natural  gas,  distillate  oil  and  residual
oi1 (Reference 3-4).
       Coal-fired  industrial boilers  are  generally  of  the  st ;ker design.
Pulverized coal units  are  limited  to  29  MW  (100  x 106  Btu/hr)  as a
minimum size because of  efficiency considerations (Reference  3-5).   The
KVB data contain two spreader  stokers, four  underfeed  stokers  and one
overfeed stoker.   A third  spreader stoker and  two overfeed units were
tested by Rockwell  (Reference  3-6).   These  data  for  spreader  stokers are
consistent-with utility  boilers  of the same  category.  The averages  for
the underfeed and  overfeed units appear  reasonable.  Based on  the
bituminous coal NO emission factors  for  both  spreader and underfeed
                   P\
stokers, a value of 9  Ib/ton (240  ng/J)  is  suggested rather  than the
6 Ib/ton (160 ng/J) currently  employed.   The  underfeed stoker  lignite
value, however, should be  retained.   Also there  are  not  enough data  for
lignite coal-fired spreader  stokers to improve on the  existing overfeed
stoker NO  emission value  for  lignite.
3.2    HISTOGRAMS  OF NO  EMISSIONS FOR INDUSTRIAL BOILERS
                       A
       Figure 3-1  shows  bar  graphs of baseline emission  valuer versus
class of boiler for those  classes  in  which  more  than two NO   emission
numbers were gathered.   The  variation within  each boiler anc  "uel  category
may be due to .load (not  all  baselines were  run at 80 percent  load),  air
preheat, burner type,  furnace  dimensions, differences  in fuel  nitrogen,
amount of excess air,  errors in  measurement,  to  name a few.   Because of
the number of variables, the data  are presented  to  only  two  significant
figures.  All baseline data  found  were included.
3.3    NITRIC OXIDE AS PERCENT CONSTITUENT  OF  TOTAL  NO  EMISSIONS
                                                       A
       The total nitrogen  oxides (NO  ) emissions consist primarily of
                                    A
two components:  Nitrogen  dioxide  (N02)  and  nitric  oxide.   T;-.JS, if  the
concentration of two are known,  the third can  be determined  to some  degree
of accuracy.
       KVB determined  NO and N0v on almost  all boilers te':sd  during its
                               /\
two field investigations.  Table 3-3  contains  this  data  reduced  to percent
NO in NO .  As can be  seen,  the  average  percent  NO  in  NO,  is  at  least
        A                                                '.
94.  The ratio of  NO to  NO   does not  seem to  be  affected :-y  fuel type  or
                           A
boiler type or size.
                                      22

-------
4 -l
nj-n Average
A '//.7/7X//M/A/// V/\
100 150
I
(40)

200 250
1
(80)
5
i
'//VA V/A
300
1
(120)
                  NO  emission factors, lb/106  scf (ng/J)

            a.  Natural Gas-Fired  Front Wall  Watertube Units
U1
c
=>
w
o
HI
.0
3

4 -i
3 -
9 —
l


Aver
i
///[/// K//1 I//I 7/1
age

7A V//VA
V •' 1 I
50 75 100 125
\ . .

s
4
P
<:


150
       (20)
         (30)
(40)
(50)
/I -.

3 -


1 -
      NO  emission factors,  lb/10  scf (ng/J)

b.   Natural Gas-Fired Front Wall Firetube Units


    Average
1 f^
7/VA
V 1 i
15 20
A.
V/fl/A,
25
               (55)
                 (70)
                  NO  emission factors, lb/10  gal (ng/J)

            c.  Distillate Oil-Fired Front Wall  Watertube Units
(60)
 Figure 3-1.
    Population histograms  of NOX emission  factors
    for  industrial  boilers.
                                 23

-------
                      Average
                   m   m
                                      (80)
               iNO  emission factors,  lb/10   gal  (ng/J)
              Distillate Oil--ired Front  Wall  Firetube Units
                          Average
                                                  :no)

25
i

22
W
m
//](///


tWt
WL
m m
iii
50 75 '00 125
1 1
(200) (330)
               NC  emission factors,  lb/10^  gal  (ng/J)
          e.   Residual Oil-Fired Front Wall WatertuDe Units
             Average
                 m
-V-i
                     40
                    50
                                  dob)
   (120)          .   ..
NO  emission  ^actors, lb/10  gal  (ng/J)
           *'.   Residual Oil-^irea Front Wall  Firetube Units
                    Figure  3-1.    Continued.
                                 24

-------
4 -i
3 -
2 -
1 _
Ave
. m i
rage
V i i
10 15
n
j
H
«c
20
       (180)
(270)
       NO  emission factors,  Ib/ton (ng/J)
         A

g.   Bituminous Coal-Fired Spreader Stokers
 4

 3

 2 -

 1 -
Average
wm M
• \
5
i
(90)
I
10
(180)
1
15
(270)
       NO  emission factors,  Ib/ton (nq/J)
         A

h.   Bituminous Coal-Fired Underfeed Stokers
       Figure 3-1.  Concluded.
                 25

-------
 TABLE 3-3.  NITRIC OXIDE AS A CONSTITUENT OF TOTAL  NOX  EMISSIONS
             OF INDUSTRIAL BOILERS
Type
Boiler
Watertube
Firetube
Spreader
Stoker
Underfeed
Stoker
NO/NOX as a Function of Fuel3
Bituminous
Coal


98% (2)
93% (4)
Residual
Oil
99% (12) a
98% (4)


Distillate
Oil
97% (3)
95% (5)


Natural
Gas
95% (8)
94% (9)


aWeight percentage, NO reported as ';02
^Numbers in parentheses refers to number of boilers  tested
                                 26

-------
3.4    EFFECT OF CONTROLS ON NO  EMISSIONS FOR INDUSTRIAL BOILERS
                               A
       No long term testing of state-of-the-art NO  emission controls
                                                  A
has yet been undertaken for industrial boilers.  Because of this, it is
difficult to say whether the NO  control techniques developed for
                               A
utility boilers will be equally effective for industrial boilers.  Short
term tests by KVB and others do indicate, however, that combustion
modification control techniques are effective in reducing NO
                                                            A
(References 3-7, 3-8, 3-2 and 3-3).  It is not yet recommended that these
limited controlled emissions data be published in AP-42.
3.5    OTHER DATA
       One data source for coal-fired boilers which met the requirements
for inclusion in the survey was that of Ferrari (3-9).  However, the data
are presented separately for two reasons:
       t   The source of the data is Australia and, although the boilers
           may be basically the same, some may be different in design.
       t   Where the data overlaps the data in this study; they  are quite
           different and generally do not follow the expected trend with
           unit size.
       Table 3-4 lists Ferrari's values and compares them with averages
for all of the boiler types for which the design is specified.   Ferrari
also reported on pulverized coal units but failed to indicate the type of
units tested.  However, his results for pulverized coal are considerably
lower than the averages for tangential, single wall and horizontally
opposed boilers in the utility category.
                                     27

-------
 TABLE  3-4.   COMPARISON OF DATA FROM FERRARI et al.  WITH CALCULATED

             AVERAGES FOR SAME BOILER TYPE AND SIZE
Type Unit
Chain Grate Stokers
(overfeed)
Spreader Stokers
NOX emission factors (ng/J)
as function of boiler size
Utility
141 (4)a
166
260 (5)
Industrial
137 (2)b
HOC (3)
192 (2)
250 (3)
 Top row Ferrari's values.


 Numbers in parentheses refer to number of boilers tested,


'Bottom row,  NO  emissions  update averages.
               X
                                 28

-------
                            REFERENCES FOR SECTION 3
3-1.  ."Task 2 Summary Report -- Preliminary Summary of Industrial  Boiler
      Population," prepared by PEDCo in support of OAQPS work on NSPS for
      industrial  boilers,  June 29,  1978.

3-2.  Cichanowicz, J. E.,  et al.,  "Pollutant Control  Techniques for Package
      Boilers.  Phase I  -- Hardware Modifications and Alternate Fuels,
      Ultrasystems Draft Report for EPA 68-02-1498, November 1976.

3-3.  Heap, M. P., et al., "Reduction of Nitrogen Oxide Emissions  from Field
      Operating Package  Boilers,  Phase III," EPA-600/2-77-025, NTIS-PB 269
      277, January 1977.

3-4.  Barrett, R.  E.  and S. E. Miller, "Field Investigation of Emissions from
      Combustion  Equipment for Space Heating," Battelle-Columbus Laboratories,
      EPA-R2-73-084a, API  Publication 4180, June 1973.

3-5.  "Task 7 Summary Report -- Technical  and Economic Bases for Evaluation of
      Emission Reduction Technology," prepared by PEDCo in support of OAQPS
      work on NSPS for industrial  boilers,  June 2, 1978.

3-6.  Littman, F.  E., et al.,  "Regional Air Pollution Study.  Point Source
      Emission Inventory," EPA-600/4-77-014, March 1977.

3-7.  Cato, G. A.  et  al.,  "Field Testing:  Application of Combustion
      Modifications to Control Pollutant Emissions from Industrial  Boilers --
      Phase 1," EPA-600/2-74-078a,  NTIS-PB  238 920/AS, October 1974.

3-8.  Cato, G. A.  et  al.,  "Field Testing:  Application of Combustion
      Modifications to Control Pollutant Emissions from Industrial  Boilers --
      Phase 2," EPA-600/2-76-086,  NTIS-PB  253 920/AS, October 1974.

3-9.  Ferrari, L.  M., et al.,  "Nitrogen Oxides Emissions and Emission Factors
      for Stationary  Sources in New South  Wales," International Clean Air
      Conference,  The Clean Air Society of  Australia and New Zealand," May
      1967.
                                     29

-------
                                  SECTION 4
                      COMMERCIAL  AND RESIDENTIAL UNITS
       This section not only covers  all  stationary  steam generating
sources whose rated heat  input capacity  is  less  than 2.9 MW  (< 10 x 10
Btu/hr) but also residential hot water,  steam  and forced air  heaters.  The
arbitrary dividing line between commercial  and residential units is  set  at
150 kW (5 x 10  Btu/hr).  As noted previously  in the introduction to
industrial boilers, nearly 26 percent of the boilers used  in  industry  have
input capacities less than 2.9 MW.   Thus,  some commercial  boiler data  were
obtained from industrial  boiler reports.
4.1    NO  EMISSION FACTORS FOR COMMERCIAL  SIZED BOILERS
         /\
       Commercial boilers fall into  three  categories:  stoker  fed
coal-fired, hand fed coal-fired, and oil-  or gas-fired  units  generally of
a firetube design.  Many  are used as a source  of hot water rather than' a
source of steam or electricity.  Tables  4-1 and  4-2 contain  information  on
those units whose NO  emissions have been  measured.
                    X
       The initial KVB boiler survey (Reference  4-1) contains  data on  two
firetube boilers with heat input capacities of 2.1  MW  (7 x 10  Btu/hr)
and 2.4 MW (8 x 10  Btu/hr).  One of these units was run with  two grades
of residual oil, distillate oil and  natural gas.  The  other  was run  with
natural gas only.  The oil data have previously  been incorporated into
AP-42, supplement 6 (Reference 4-2).  The  natural gas  data are 22 percent
lower than the existing AP-42 number which  is  composed  solely of the
results from seven boilers tested by Battelle  (References  4-3  and 4-10).
However, two of these Battelle units were  industrial size  and  the data
have been recalculated to reflect this.  Thus, the  new  value is the
arithmetic average of the remaining  five units plus the two  KVB results.
                                      30

-------
       TABLE 4-1.  NOX EMISSION FACTORS SURVEY OF COMMERCIAL STATIONARY STEAM AND HOT WATER
                   GENERATING UNITS (0.5 to 10 x 106 Btu/hr) (ENGLISH UNITS)
Type
Boiler
Firetube
Commercial
Stokers
Commercial
Hand-Fired
Units
Baseline NOX Emissions as a Function of Fuel9
Coal (Ib/ton)
Anthracite

2.2-3.2f (1)
3
Bituminous

6.0
3.0
Lignite

6.0

Oil (lb/l()3 gal)
Residual
60b
6ic (8)d
2e


Distillate
22
19 (7)
-14%


Natural Gas
(lb/106 SCF)
120
92 (7)
-22%


aNO  values reported in terms of NO-
D01d AP-42 value
'Recommended replacement number based on new or revised data base
 Number  of boilers tested
^Percent change in emissions factor
 Range as reported in literature, best available information (Reference 4-5)

-------
     TABLE 4-2.   NOX EMISSION FACTORS SURVEY OF COMMERCIAL  STATIONARY  STEAM
                    AND HOT WATER GENERATING UNITS (0.15 to 2.9 MW)  (SI UNITS)
Type
Boiler
i
i
Firetube
Commercial
Stokers
Commercial
Hand-Fired
Units
Basline NOX Emissions (ng/J) as Function of Fueia
Coal
Anthracite

37-55(l)f
51
Bituminous

110
54
Lignite

160

Oil
Residual
172°
180C (8)d
2e


Distillate
67
58 (7)
-15%


Natural Gas !
1

49
38 (7)
-22*
i

aNO  values reported in terms of NO-
b01d AP-42 value
cRecommended replacement number based on new or revised  data base
,1
 Number of boilers tested
ePercent change in emissions factor
 Range as reported in literature, best available information (Reference 4-5)
EE-T-119
                                               32

-------
       Battelle (Reference 4-3) has also tested a 200 kW commercial boiler
fitted with both bituminous and anthracite stokers.  This unit was
operated at extremely low loads for most of the test sequences in an
attempt to achieve smokeless results.  The NO  emission factors reported
                                             A
here for anthracite were run at 74 percent load and the bituminous at 49
percent load.  Because of the low load and large excess air conditions,
incorporation of the bituminous coal data in AP-42 is not recommended and
have not been included in the reported average.
4.2    N0v EMISSION FACTORS FOR RESIDENTIAL FURNACES AND BOILERS
         A
       Residential units fall into the same broad categories as the
commercial boilers, above.  NO  emission data for residential units
                              n
are contained in Tables 4-3 and 4-4, in English units and SI units,
respectively.
       Monsanto (Reference 4-6) has recently published information on a
200,000 Btu/hr furnace and a 200,000 Btu/hr boiler.  Both units are
supplied by underfeed stokers and fired with western subbituminous coal.
Average baseline NO  for the two units is 8.5 Ib/ton (152 ng/J).  The
                   A
NO  emission factors were approximately twice as great for the furnace
  A
as for the boiler using the same coal.  This suggests that design features
may play an important part in NO  emission factors for these units.
                                A
       Several recent sources of data on NO  emissions for natural
                                           /\
gas-fired residential units have been abstracted (References 4-7, 4-8, and
4-9).  The most extensive results, conducted by The American Gas
Association (AGA) Laboratories (Reference 4-7) cover 38 gas-fired, forced
air furnaces manufactured by 29 different companies with heat input rates
                    3            3
ranging from 75 x 10  to 180 x 10  Btu/hr.  The average NOX emission
factors for these units are 103 Ib N02/105 scf (42.1 ng N02/J) and
they ranged from 18.8 to 128.1 Ib N02/106 scf (7.7 to 52.5 ng N02/J).
The lowest number was considered outside of acceptable limits and was
discarded for the final average.  The data for the blue flame, high 02
condition, were considered as baseline.  A second, low excess air (yellow
flame adjustment) testing sequence showed an average 10 percent decrease
in NO  emissions for this control technique.
     A
       Hall (Reference 4-8) reports on the testing of two gas-fired
furnaces and one gas-fired boiler.  In these tests NO measurements
averaged 60.5 Ib NO/106 scf (24.8 ng NO/J).  If one assumes that  at

                                     33

-------
TABLE 4-3.   NOX  EMISSION  FACTORS SURVEY  OF RESIDENTIAL STEAM  AND
              HOT  WATER GENERATING UNITS  (<500,000 Btu/hr)
              (ENGLISH UNITS)
Typ*
Boiler
Residential
Heating
Stoker
Units
Hand-Fired
Units
Baseline NOX Emissions as a Function of Fuel3
Coal (Ib/ton)
Anthracite

6.0
8.5 (2)
42X
3. Ob
Bituminous

6.0

Lignite



Oil (lb/103 gal)
Residual



Distillate
18


Natural Gas
(lb/100 SCF)
80*>
102C (44)d
+28X*


 NO  values  reported  in terms of NO.
b01d AP-42 value
cRc-commended replacement number based on new or revised data  base
 N'.moer of boilers tested
 P="cent change in emissions factor
                                                                         EE-T-122

-------
                         TABLE 4-4.   NOX EMISSION FACTORS SURVEY OF RESIDENTIAL (<0.15 MW)
                                  -   STEAM AND HOT WATER GENERATING UNITS (SI UNITS)
Type
Boiler
Residential
Heating
Stoker
Units
Hand-Fired
Units
Baseline NOX Emissions (ng/J) as a Function of Fuel3
Coal
Bituminous

107
152 (2)
42%
54b
Lignite

160

Oil
Residual



Distillate
55b


Natural Gas

33 b
42C (44)d
+28%e


CO
en
            NO   values  reported  in terms  of N02
            b01d  AP-42 value
            GRecommended replacement number  based on new or revised data base
            Number  of boilers  tested
            Percent  change  in  emissions factor

-------
least 90 percent of NO   is NO then the NO  concentration  (measured  in
terms of N02) is 102  ib  N02/105 scf  (41.8 ng N02/J).  The units
tested by Hall were "as  is."  Those  by the AGA were tuned (blue flame).
In both cases, the tests were considered baseline.  Similar  lack of
effects of boiler tuning on NO  emissions were shown by KVB  for
                              /\
industrial boilers (Reference 4-10).
       Finally, Rocketdyne (Reference 4-9), prior to testing various
modifications on the  unit, procured  and tested a Lennox 011-140 warm air
furnace equipped with a  stock Lennox Burner.  A baseline run on the unit
gave 98 Ib NO/106 scf (40 ng NO/J).  This is equivalent to 167 Ib
N02/106 scf  (68 ng N02/J) of N0x measured as N02 if the NO as
measured previously accounted for 90 percent of the NO .
                                                      A
       Summation of these 41 individual boilers with the two units
previously averaged in AP-42 Supplement 3 (Reference 4-11) gave 102 Ib
N02/10  scf  (42.0 ng/J)  as the overall average.
4.3    NOV EMISSION FACTORS FOR PILOT LIGHTS
         X
       Most  residential, gas-fired waterheaters and forced air furnaces
contain pilot burners.   Fuel input ranged from 828 to 1570 Btu/hr for the
seven pilot  lights examined by the AGA (Reference 4-7).  The average NO
emission factor for these pilots is  71.3 lb/106 scf (29.2 ng/J), roughly
75 percent of that for the burners.
4.4    HISTOGRAMS OF  N0v EMISSIONS FOR COMMERCIAL AND RESIDENTIAL UNITS
                       X
       Population NO  emission histograms are drawn for gas-fired
                    A
commercial boilers, residential heating units and pilot lights.  These
histograms are shown  in  Figure 4-1.  All data are within acceptable limits
except the 7.7 ng/J residential unit reported by Thrasher and Dewerth
(Reference 4-7).
4.5    NITRIC OXIDE AS PERCENT CONSTITUTENT OF TOTAL NOV EMISSIONS
                                                       X
       Much  of the data  reviewed was reported in terms of either NO and
NO? or NO and NO .  These data are presented in Table 4-5.   A trend in
  £             A
the data seems to indicate that the  smaller the source, the  greater the
fraction of  NO in the NO  emissions.  The pilot light data and 38 data
                         A
points for gas-fired  residential units were reported by the  American Gas
Association  Report (Reference 4-7).  The remaining N0/N02 data were
taken from two older  Battelle documents (Reference 4-3 and 4-4).  Data for
commercial units were reported by Battelle  (Reference 4-3) and KVB
(Reference 4-1).

                                     36

-------
5-
4-
3-
2-
i _
i

Average

V*
^ '//A //A//.
"•
p
// Y//\
VI I I i i i
10 20 30 40 50 -. 60
I i 1
50 100 15
   7 -,
   3-
CJ
-e  2-
                       Emission factor, ng/J (Ib x 10  scf)

                     a.  Natural  Gas-Fired Commercial Boilers
                                                          m
               10
20
30
40
50
                       Emission factor, ng/J (Ib x  10  scf)

                      b.  Natural Gas-Fired Residential Units
60
1
50
! 1
100 1!
4-
3-
1 -
0
Aver
\
₯/$//////_
10 20 3(
age
n
//i
^

i i
3 40 50
i i
50 100
                       Emission factor, ng/J  (16 x 10  scf)

                                c.  Pilot Lights
   Figure 4-1.   Population  histograms of NO* emission factors for
                  natural  gas-fired commercial  boilers, residential
                  units,  and  pilot lights.
                                       37

-------
TABLE 4-5.  NITRIC OXIDE AS A CONSTITUENT OF TOTAL NOX EMISSIONS
            OF COMMERCIAL AND RESIDENTIAL BOILERS AND HEATING UNITS
            AND PILOT LIGHTS

Type
Boiler


Commercial
0.5 to 10 x 106
Btu/hr
Residential
2 to 500 x 10 3
Btu/hr

Pilot Light
<2000 Btu/hr
NO/NOX as a Function of Fuel3


Natural
Gas
97 (8)b


As found
79 (2)
Tuned
95 (38)
55 (7)


Distillate
Oil
99 (7)


75 (32)






Residual
Oil
99 (7)








 Weight percentage, NO reported as N09
                                     £
 Numbers in parentheses refers to number of boilers tested,
                                38

-------
                            REFERENCES FOR SECTION 4
4-1.   Cato, G.  A.  et al.,  "Field Testing:   Application of Combustion
       Modifications to Control  Pollutant Emissions from Industrial
       Boilers — Phase I," EPA-600/2-74-078a,  NTIS-PB 238 920/AS,
       October 1974.

4-2.   U.S. Environmental  Protection Agency, "Supplement No.  6 for  Compilation
       of Air Pollutant Emission Factors,"  Second Edition, Office of Air
       Quality Planning and Standards,  Document AP-42, April  1976.

4-3.   Barrett,  R.  E., et  al.,  "Field Investigation of Emissions from
       Combustion Equipment for  Space Heating," EPA-R2-73-084a (API
       Publication  4180),  June  1973.

4-4.   Levy, A., et al., "A Field Investigation of Emissions  from Fuel Oil
       Combustion for Space Heating," API Publication 4099, November 1971.

4-5.   Giammar,  R.  D., et  al.,  "Emissions from Residential and Small
       Commercial Stoker-Coal-Fired Boilers Under Smokeless Operation,"
       EPA 600/7-76-029, October 1976.

4-6.   DeAngelis, D. G., and R.  B. Reznik,  "Source Assessment:  Coal-Fired
       Residential  Combustion Equipment Field Tests, June 1977, "EPA
       600/2-78-0040, June 1978.

4-7.   Thrasher, W. H. and D. W. Dewerth, "Evaluation of the  Pollutant
       Emissions from Gas-Fired  Forced Air  Furnaces," American Gas  Association
       Research  Report #1503, Catalog No. U7815, May 1975.

4-8.   Hall, R.  E., et al., "A  Study of Air Pollutant Emissions from
       Residential  Heating Systems," EPA 650/2-74-003, January 1974.

4-9.   Combs, L. P., and A. S.  Okuda, "Residential Oil Furnace System
       Optimization, Phase II,"  EPA 600/2-77-028, January 1977.

4-10.  Cato, G.  A., et al., "Field Testing: Application of Combustion
       Modifications to Control  Pollutant Emissions from Industrial  Boilers —
       Phase 2," EPA-600/2-76-086a, NTIS-PB 253 500/AS, April 1976.

4-11.  U.S. Environmental  Protection Agency, "Supplement No.  3 for  Compilation
       of Air Pollutant Emission Factors,"  Second Edition, Office of Air
       Quality Planning and Standards,  Document AP-42, July 1974.
                                     39

-------
                                 SECTION 5
                      STATIONARY RECIPROCATING ENGINES
       Reciprocating engines consist of two major subclasses, compression
ignition (CI) and spark  ignition (SI).  Each subclass  is divided into
two-stroke and four-stroke engine cycle categories (Reference 5-1).
Further division by engine use has also been customary  (Reference 5-2 and
5-3); however, because engine type and size are constantly changing within
each use category, the substitution of rated power output is recommended.
5.1    NOV EMISSION FACTORS FOR COMPRESSION IGNITION ENGINES
         /\
       These engines are divided into three power output categories; large
(>75 kW/cyl), medium (75 kW/cyl to 75 kW/engine), and  small (<75 kW/engine)
Further division is by fuel type and by engine cycle.  Two fuel types are
characteristic of compression ignition engines; diesel engines, burning
diesel oil fuel, and dual fuel engines, burning a mixture of diesel oil
and gas (natural and synthetic) consisting of anywhere from  >95:5 to
<5:95 parts by weight of the two fuels.  Some dual fuel engines also have
the capability of burning each fuel separately.
       Table 5-1 gives the emission factors in 3 different units.  To
convert from output specific units, e.g., gm/hp-hr, to  input specific
                           3               3
units, e.g., ng/J and Kg/10  liter or lb/10  gal, heat rates for
compression ignition engines were estimated.  These are presented in Table
5-2.
       The nitrogen oxides emissions factors for large  and medium CI
engines were reported in the Standards Support Document (Reference 5-1)
and Hare and Springer (Reference 5-4).  NO  emission factors for small
engines were found in Marshall and Fleming (Reference  5-5) in addition to
Hare and Springer.
                                     40

-------
               TABLE 5-1.  BASELINE  NOX  EMISSION  FACTORS SURVEY OF RECIPROCATING
                           COMPRESSION  IGNITION  (CI)  ENGINES
Engine
Size
Large
>75 kW/cyl.
Medium
75 kW/eng.
-75 kW/cyl.
Small
<75 kW/eng.
Units
ng/Jb
g/hp-hr
lb/103 galb
No. Engines
ng/Jb
g/hp-hr
lb/103 galb
No. Engines
ng/Jb
g/hp-hr
lb/103 galb
No. Engines
NOX Emissions as a Function of Stroke and Fuela
Diesel oil
2 Stroke
1800
13.3
600
(14)
1980
16.1
660
(23)
—
4 Stroke
1200
8.8
400
(19)
1100
9.0
360
(66)
1300
10.5
430
(15)
Dual Fuel
2 Stroke
1520
10.4
__c
(3)


4 Stroke
1260
8.6
__c
(6)


 NO.
values reported in terms of N0?
 Input  Specific
"Constituent  ratio  of  dual  fuel  unknown
                                       41

-------
          TABLE 5-2.  HEAT RATES FOR COMPRESSION IGNITION ENGINES
Engine Size
Large

Medium and Small
Fuel
Diesel
Dual
Diesel
Heat Rate (Btu/hp-hr)
7000 (Reference 5-1)
6500 (Reference 5-1)
7680 (Reference 5-3)
       AP-42, Supplement 4 previously lists Hare and Springer data without
differentiation as to size or number of strokes per firing cycle.
5.2    NO  EMISSION FACTORS FOR SPARK IGNITION ENGINES
         /\
       Spark ignition (SI) engines are divided into four categories of
power output; large ( >75 kW/cyl), medium  (75 kW/cyl to 75 kW/engine),
small (15-75 kW/engine) and very small (<15 kW/engine).  Like compression
ignition engines, these engines, are further divided by engine cycle and
fuel type.  The principal fuels for spark ignition engines are gasoline
and natural gas.  Table 5-3 contains the  average NO  emissions factors
                                                   /\
for these engines.
       A substantial body of data was acquired for natural gas-fired  large
and medium sized, stationary, spark ignited (SI) engines (References  5-1,
5-6, 5-7, and 5-8).  The current emission factors are 20 percent higher
for two-stroke engines and 40 percent higher for four-stroke engines  than
those in AP-42, which are based on Urban  and Springer and Dietzman and
Springer alone (Reference 5-6 and 5-7).  The best data available were
considered to be that of Dietzman and Springer which were repeated in
Urban and Springer.  These were used in the averages in Table 5-3.  These
data agreed well with that abstracted from References 5-1 and 5-6.
       Data for gasoline fired SI engines were obtained for all categories
except large engines (References 5-4, 5-9, 5-10, and 5-11).  Numbers  for
the small and very small engine categories are from Hare and Springer
(Reference 5-4).  They have previously been abstracted into AP-42 under
"industrial equipment", Section 3.3.3, and "small, general utility
engines", Section 3.2.5.  There are no additional data in these
categories, but a minor adjustment was necessary.  The values reported
                                    42

-------
  TABLE  5-3.   BASELINE  NOX  EMISSION  FACTORS  SURVEY  OF  RECIPROCATING

              SPARK  IGNITION  (SI)  ENGINES
Engine
Size
Large
>75 kW/cyl.
Medium
75 kW/eng.
-75 kW/cyl.
Small
15-75 kW/eng.
Very Small
<15 kW/eng.
Units
ng/jb
g/hp-hr
lb/103 galb
lb/10b SCFb
No. Engines
ng/jb
g/hp-hr
lb/103 galb
lb/10b SCFb
No. Engines
ng/jb
g/hp-hr
lb/103 galb
No. Engines
ng/Jb
g/hp-hr
lb/103 galb
No. Engines
NOX Emissions as a Function of
Stroke and Fuela
Gasoline
4 Stroke

740
10.8
260
9
310
5.4
110
3
198
5.0
69
5
Natural Gas
2 Stroke
1660
13.2
4000
55



4 Stroke
1960
15.5
4800
24
1600
12.7
3900
23


aNO   values  reported  in terms  of N0?
.   X                               c.

 Input specific values, all  others are output specific
                                   43

-------
herein are computed  on  an evenly weighted  average  and  one  engine  that  was
not tested at baseline  was  deleted.
5.3    HISTOGRAMS OF NO EMISSIONS FOR RECIPROCATING ENGINES
                        ^
       Population versus NO  emission factor  histograms  were  drawn  for
                            /\
all of the categories of SI and CI engines for which data  were  obtained.
They appear in Figure 5-1 through 5-4.  Two of the histograms contain
blocks with numbers  superimposed on them.  These blocks  represent averages
of a particular number  of engines as reported in the literature;  values
for the individivual tests were not given.  Abscissae  of these  plots are
marked in both English  and SI  units where  possible.
5.4    NITRIC OXIDE  AS  PERCENT CONSTITUTENT OF TOTAL NO  EMISSIONS
                                                       A
       Data for percent NO  in  total NO  were  taken from  Hare  and
                                      ^
Springer, Dewerth, and  Dietzman and Springer  (References 5-4, 5-6,  and
5-8).  It is presented  by engine subclass  and category in  Table 5-4.
                                      44

-------
                                              Averaqe
A
A' 1
500

V/M
1000
«pd
I

VA Y//xm m
1500 2000 2500
              (200)    (300)    (400)    (500)    (600)    (700)

                        NO  emission factors,  ng/J (lb/10  gal)

                               a.  Large 2-Stroke
                                                            (800)     (90C)
o
V-
5 -,

4 -

3 -

2 -
1 -
                             Average

m m

'///
7/<
f/t
//<
\
y/<
Y/t

'M

y//

y//
Y/t

-------
6 -

4 -
3 -
2-
1 -
0






y/t

tfs
///
w\
Sfy
%
' //


^
3
W
^
6
5
4
Average
T

P
ft

f / /
fy/
5
4

f /£
'///
V/f
y/t
5
£
*
2 22
                500
1000
i SCO
2000
                    200
        00
          600
             NO  enission factors, nq/J (lb/'10J  cal)
                       d.  Medium, 4-Stroke
D ~
4 ""
1 -
0
Aver
j

WA 7f///j'/i '//////%////.
500 1000
200 400
age
ty/A V////A

WM m
1500 2000 • 250C
600
800
             NO  emission factors. ng/J (lb/10  gal)
                       e.  Small, ^-Stroke

   *Numbers in blocks  indicate averages of this  number of ennines as reported
    in the literature.   Shaded blocks indicate individual enoines.
                         Figure 5-1.    Concluded.
                                       45

-------
3-j
2 _
1 ~ . ,.L
^ f^
Average
1
•K51
 l/l
 01
 c
             1000
             1500
2000
2500
   NO   emission  factors,  ng/J
    X
        Large,  2-Stroke
CJ
JO
    3
    2
    1
                    Average
                                                               rj
                                                               <
                  S
              500           1000           1500
                  NO   emission  factors,  ng/J
                       Large, 4-Stroke
                                            2000
  Figure 5-2.
Population histograms of NOX emission factors for
compression ignition engines firing dual fuels.
                                 47

-------
  500
TOGO
1500
?000
2500
3000
            I
          (2000)
                    I
                 (4000)
                         (6000)
                       NO  emission factors, ng/J  (lb/10  scf)
                         x
                             a.   Larne Size, 2-?trokp
                                         Averaae
                                   (EOOO)
                                                               m
                1000
              1500
             2000
             2500
             3000
                                   I                      T
                                (400C!                 (COCO!

                       NO  emission factors, ng/J (lb/10  scf)
                             b.   Large Size,  4-Stroke
                                                    Averaae
•J — 1
4 -
3 -
2 -

0





m m m m
m
'//
//ft
/A



%

500 1000
(1000) (3000)


\




/' i

///
>/ 1
//
^
m
1 1
'//


TJ
'//
'///
i


UL
7/,
1 1
//



* t /

i
1500 2000 2500
(5000)
                        NO  emissions factors, ng/J  (Ib/"!?  scf)

                                c.  Medium  Size, 4-Stroke
Figure 5-3.   Population  histograms  of NOX  emission factors  for  stationary
                reciprocating, natural  gas firing  SI engines.
                                           48

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4 -,
3 -
2 -
1 -
0
Average
i
m m
'//
m
7i\ n
//
m m -
                   200
                                          300
                (500)
            (600)
(700)
(800)
(900)
                        NO  emission factors,  lb/10  gal (ng/J)
                                  a.  Medium

m
V
\
(200)
Ave
i
i
100
I
(300)
rane
w,
1
150
1
(400)
w\

1
(500)
                        O  emission factors,  1b/10° gal (ng/J)
                                    b.  Small
(1000)
3 -
2 -
1 -
0
Average
m m vfl v\ m
50
i i
(100) (200)
100
i i
(300) (400;
                           enission factors,  lb/10  gal (nn/j)
                                  c.  Very Smal 1
Figure  5-4.
Population histograms  of NOX  emission factors for  stationary
reciprocating  gasoline fired  Spark  Ignition  engines.
                                         49

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     TABLE  5-4.   NITRIC OXIDE AS A CONSTITUENT OF TOTAL NOX EMISSIONS
                 OF RECIPROCATING ENGINES
Engine
Size
Large
Medium
Smal 1
NOX Emissions as a Function of Type, Stroke, Fuel and Size9
Compression Ignition
Diesel Fuel
2 Stroke
—
93 (1)
—
4 Stroke
—
96 (4)
98 (3)
*
Spark Ignition
Natural Gas
2 Stroke
88 (42)b
—

4 Stroke
83 (9)
96 (15)

f
Gasoline


98 (3)
^Weight percentage, NO reported as NOp
•'Number in parentheses refers to number of engines tested
                                  50

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                          REFERENCES  FOR  SECTION 5
5-1   Youngblood,  S.  B.  et al.,  "Standards  Support and Environmental  Impact
      Statement for Reciprocating Internal  Combustion Engines,"  Acurex Draft
      Report TR-78-99,  March 1978.

5-2   Anon, "Compilation of Air  Pollution Emission Factors,"  U.S.
      Environmental Protection Agency,  Office of Air Quality  Planning and
      Standards, Publication AP-42,  April 1973 and.Supplements.

5-3   Shimizu, A.  B.,  et al.,  "NOX Combustion Control Methods and  Costs for
      Stationary Sources -- Summary Study," EPA 600/2-75-046, September 1975.

5-4   Hare, C. T.  and  K. J. Springer,  "Exhaust Emissions from Uncontrolled
      Vehicles and Related Equipment Using  Internal  Combustion Engines, Final
      Report — Part 5,  Heavy-Duty Farm,  Construction and Industrial  Engines,"
      Southwest Research Institute,  San Antonio, Texas, AR-898,  October 1973.

5-5   Marshall, W. F.  and R. D.  Fleming,  "Diesel Emissions Reinventoried,"
      Report of Investigations No.  7530 by the U.S.  Department of  the
      Interior, Bureau  of Mines, 1972.

5-6   Dietzmann, H. E.,  and K. J. Springer, "Exhaust Emissions from Piston and
      Gas Turbine Engines Used in Natural Gas Transmission,"  Southwest
      Research Institute, San Antonio,  Texas, prepared for American Gas
      Association, Arlington, VA, January 1974.

5-7.  Urban, C. M. and  K. J. Springer,  "Study of Exhaust Emissions from
      Natural Gas Pipeline Compressor Engines," Southwest Research Institute,
      San Antonio, Texas, prepared for  American Gas Association, Arlington,
      VA, February 1975.

5-8   Dewerth, D.  W.,  "Air Pollutant Emissions from Spark-Ignition Natural Gas
      Engines and Turbines," American Gas Association Laboratories Research
      Report No. 1491,  September 1973.

5-9   Hare, C. T.  and K. J. Springer,  "Exhaust Emissions from Uncontrolled
      Vehicles and Related Equipment Using Internal  Combustion Engines, Final
      Report, Part 4,  Small Air-Cooled  Spark Ignition Utility Engines," U.S.
      Environmental Protection Agency,  APTD-1493, May 1973.

5-10  Fleming, R.  D. and F. R. French,  "Durability of Advanced Emission
      Controls for Heavy Duty Diesel and Gasoline Fueled Engines,"
      EPA 460/3-73-010,  September 1973.

5-11  Springer, K. J.,  "Baseline Characterization and Emissions Control
      Technology Assessment of Heavy-Duty Gasoline Engines,"  Final Report
      Southwest Research Institute, San Antonio, Texas, AF-844, November 1972.
                                   51

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                                 SECTION 6
                                GAS TURBINES
6.1    NOX EMISSION FACTORS FOR VARIOUS TYPES AND SIZES OF GAS
       TURBINE ENGINES
       For the purpose of this study, gas turbines have been divided  into
three sizes:  large >15 MW (>20,000 hp), medium, 4 to 15 MW  (5300  hp  to
20,000 hp) and small, <4 MW (<5300 hp).  The units were further  divided
into simple and regenerative cycle* and subsequently classified  as  to
fuel.  As no distinction could be made between the various types of oil
burned, all of these were combined into liquid fuel.  The liquid fuel
category does not  contain derived fuels such as methanol but does  include
heavy distillates  and crudes when reported.
       Table 6-1 contains a summation of the data extracted.  Much  of  the
information was obtained from the Standard Support Document  (Reference 6-1)
Other sources include Dietzman and Springer  (which has already been
incorporated into  Supplement 6 of AP-42) (Reference 6-2), Dewerth
(Reference 6-3), Wasser  (Reference 6-4), Crawford, et a!., (Reference  6-5)
and Acurex (Reference 6-6).  Much of the data contained heat rates  for the
units tested so that it was possible to determine input specific (Ib/MBtu,
ng/J, lb/10  scf or lb/10  gal) as well as output specific (ppm  at  15
percent 02, Ib/MWH, g/hp-hr) NOX emission terms.
6.2    HISTOGRAMS  OF N0₯ EMISSIONS FOR GAS TURBINE ENGINES
                       A
       Figure 6-1  shows population NO  emission factor histograms  for
                                     ^
the six classes of gas turbine engines in which data on more than  two
units were found.  The graphs for the small  turbine category show  numbers
*Regenerative  units  use  exhaust  gases  to  preheat  combustion  air,
                                    52

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         TABLE  6-1.   N0x  EMISSION FACTORS SURVEY OF SIMPLE AND


                      REGENERATIVE CYCLE  GAS ENGINES

Turbine
Size

Large
>15 MW
(>20,000 hp)





Med i urn
4 to 15 MW
(5,300 to
20,000 hp)





Small
<4 MW
(<5,300 hp)







Units

No. Engines h
ppm @ 15* 02
lb/MWHb
g/np-hrb
ng/Jc
lb/MBtuc
lb/MSCFC
or
lb/103 gal
No. Engines b
ppm 1? 15!t 02
lb/MWHb
g/hp-hrb
ng/Jc
Ib/MBtuC
lb/MSCFC
or
lb/103 gal
No. Engines b
ppm @ 15% 02
lb/MWHb
g/hp-hrb
ng/Jc
Ib/MBtuC
lb/MSCFC
or
lb/103 gal
Baseline NOX Emissions as a Function of Cycle and Fuel3

Simple Cycle
Natural Gas
4
98
4.1
1.4
140
0.32
350

—
8
80
3.8
1.3
120
0.29
300

—
30
78
4.9
1.7
120
0.28
300

—
Liquid Fuel
16
188
10. 2d
3.5^
360
0.85
—

120
3
108
6.1
2.1
210
0.48
—

70
58
93
5.6
1.9
180
0.41
—

47

Regenerative Cycle
Natural Gas
__
._
::
—
—
~

—
„
_.
—
—
—
—
—

—
i
__
6.2
2.1
180
0.42
440

—
Liquid Fuel
2
340
12.0
4.1
650
1.51
—

220
..
_.
-_
—
--
—
—

--
1
--
11.4
3.8
360
0.84
—

120
aNO  values reported in terms of NO,
U X                           L.

 Output specific values


clnput specific values


 Average of 14 units only
                                      53

-------
4 —
3 —
i


•~ 5 — i
= 4 _
1 3 _
_ /
5
^ 1 	

"H7 Average
/7/Y ^/
„ I//J//////////X//// Mfl !//] I///)
200 300 400 500 600 700
I I 1
.0.5) (1.0) (i.5)
NO emission factors. nq/J (Ib/MBtu)
a. Large, Simple Cycle, Liquid Fuel Fired
Average
I
m w, m
v i 1 | 1
50 100 150 200
                 (0.3)         (0.4;

                              ng/J

          Large, Simple  Cycle, Natural Gas Fired
                          NO  emission  factors,  ng/J (Ib/MBtu)
             (o.i;
                                 Average
2 -
1 -
_A __


//
m
i
m
A/ 1 i
50 100 150

VM

\
200
         (0.2)
(0.3)
(0.4)
(0.5)
                          NO  emission factors, ng/J (Ib/MBtu)

                       c.  Medium,  Simple Cycle, Natural Gas Fired
Figure 6-1.
Population  histograms  of NOX emission  factors
for  gas turbine  engines.
                                 54

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A




V/A
100 l'50
(0.25)
Average
!
WA W\
2"00 2*50 3do
(o.'so) (o1.
                        NO  emission factors,  ng/J  (Ib/MBtu)


                    d.  Medium, Simple Cycle,  Liquid Fuel Fired
•D
JO
                              Average
3 _
2 _
1



| 3
'w,wn//\ ui W/M* m
v ^o ido 1^0 2oo 25'o
1 1 1
(0.2) (0.2) (0.4) (.05)
                          NO  emission factors, ng/J (Ib/'IBtu)


                     e.   Small, Simple Cycle,  Natural Gas Fired
                                     Average
4 —

2 ~
l —





V/A





f//t


7flt
y/<
6
9
1



^
77
00



//
15





3





₯/
200
(0.5)

^
f//
Y/t





^V/A W/A
r "«"• |
300 400
(1.0)
                          NO  emission factors, ng/J (lb/^1Btu)


                       f.  Small, Simple Cycle, Liquid Fuel  Fired
                              Figure  6-1.   Concluded.
                                          55

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in some of the boxed squares.  These numbers represent  averages  of  NO
                                                                     A
emission values as they were presented  in the  literature;  individual
values were not presented.  The small liquid fuel fired  turbine  histogram
appears to be bimodal  in  appearance.  This  characteristic  does not  appear
to be related to turbine  size or to fuel as all four fuels, Jet  A.,
kerosene, and No. 1 and No. 2 fuel oils  appear  in both modes.  It may be
related to the make of turbine or to the method of  testing.
6.3    STATE-OF-THE-ART CONTROL TECHNIQUES  FOR  NOX  EMISSIONS —  WATER
       INJECTION
       Water injection into the combustion  zone in  either  as a liquid or
as steam has been used to  increase efficiency  since 1961 with NO
                                                                 x
control being a fringe benefit.  Not until  1971 was it  primarily used to
meet NO  regulations (Reference 6-1).  A water/fuel ratio  of 0.5
       A
generally provides a NO   reduction of 50 percent and for a water/fuel
                       A
ratio of 1.0, 80 percent.  Steam appears to be  less effective as the
energy for vaporization is no longer supplied  by the combustion  process of
the turbine.  Figure 6-2  illustrates the effect of  increasing the
water/fuel ratio in reducing the overall NO  concentration.  Steam/water
                                            A
injection appears to work  equally well for  natural  gas  and distillate oils,
6.4    NITRIC OXIDE AS PERCENT CONSTITUTENT OF  TOTAL NO  EMISSIONS
                                                        A
       Dietzman and Springer (Reference 6-2) have reported NO as a
percentage of NO  for  one  turbine firing natural gas in  the 4 to 15 MW
                A
range.  The average of the tests run was 87 percent.  Nitric oxide  (NO)
was not measured on any of the other turbines  examined  during this  test
program.  Dewerth (Reference 6-3) analyzed  two  400  hp turbines at 60
percent load for both  NO  and NO  and obtained  an 86 percent average of
                               A
NO.
       Previously, Tuttle, et al., (Reference  6-7)  reviewed much of the
data prior to 1974 and found that it was clearly contradictory as to
whether N07 (and inversely NO) is a small or large  fraction of total
NO  emissions for gas  turbine engines.  Recently Johnson and Smith
  A
(Reference 6-8) varied a  45 MW gas turbine  from idle (15 MW) to  full
load.  NO as a percentage  of NO  increased  from 0 to 78  percent  as  shown
                               A
in Figure 6-3.  This is roughly collaborated by a second test run by
Wasser (Reference 6-4) on  a 0.125 MW turbine at an  EPA  facility  as  shown
in Figure 6-4; however, results at low  loads indicate a  considerable

                                     56

-------
3U
80
70
60
c
o
4->
£ 50
T5
QJ
i-
X
O
z
g 4°
u
i_
D-
30
20
10
0
D Natural gas ^"^ Q
O Liquid fuel / Ss
/ On
/ D ° 0
-6 °o°
/ o ^,
/ ^^*
/D o 0 ^x^
/ '
1 OQ /
- i <§) /
/o /
/ D /
/ .
; /
- 1 /
- If
-,'/
/ 1 1 1 1 1

f-
(«
v»
?i
<












          0.2      0.4       0.6      0.8       1.0       1.2


                     Water/Fuel  Ratio
Figure 6-2.   Effectiveness of water/steam injection  in

              reducing NO  emissions (Reference 5-1).
                         A
                           57

-------
   120
   100  -
    80
s:
c_
c_
i   60 -
C
OJ
    40 -
    20 h
     0
      500
550
600
650
700
                     Turbine inlet temperature,  C
                                      38
                          Approximate load, MW
750
800
                                               45
             Figure  6-3.
          NO and N02 concentrations at base of No. 3
          stack for various turbine loads, i.e., turbi
          inlet temperature (Reference 6-7).
                                                                      ne
                                     58

-------
c
o
c
8
o
220


200'


180


160


140


120


100


 80


 60


 40


 20


  0
                                                                             N
                                                                             <;
                                                                         I
        20     40    60
                               80    100    120    140

                                Generator load,  kW
160   180   200   220
      Figure 6-4.
               NO and NOX concentrations of a small  turbine at various
               loads firing No. 2 oil (Reference 6-4).
                                        59

-------
quantity of NO in the EPA turbine exhaust  and  virtually  none  reported  by
Johnson -and Smith.  Also indicated  is  a dropoff  of NCL directly from the
low load value for the EPA unit whereas the Johnson  and  Smith  unit  shows
an increase prior to dropping off.  Much of this  difference  may be due  to
the difference in fuels, type and size of  the  turbine  and operating
parameters.
                                     50

-------
                            REFERENCE FOR SECTION 6
6-1.  Anon, "Standards Support and Environmental  Impact Statement Volume I:
      Proposed Standards of Performance for Stationary Gas Turbines,"
      Emission Standards and Engineering Division,  U.S. Environmental
      Protection Agency, EPA-450/12-77-017a,  September 1977.

6-2.  Dietzmann, H.  E., and K. J.  Springer, "Exhaust Emissions from Piston
      and Gas Turbine Engines Used in Natural  Gas Transmission," Southwest
      Research Institute, San Antonio, Texas.   Prepared for American Gas
      Association, Arlington, VA,  January 1974.

6-3.  Dewerth, D. W., "Air Pollutant Emissions from Spark-Ignition Natural
      Gas Engines and Turbines," American Gas  Association Laboratories,
      Research Report No. 1491,  September 1973.

6-4.  Wasser, J. H., "Emission Characteristics of Small Gas Turbine
      Engines: as reported in The Proceedings  of  the Stationary Source
      Combustion Symposium, Vol. Ill, EPA-600/12-76-152, June 1976.

6-5.  Crawford, A. R., et al., "Control of Utility Boiler and Gas Turbine
      Pollutant Emissions by Combustion Modification -- Phase 1,"
      EPA-600/7-78-036a, March 1978.

6-6.  Acurex Corporation, Unpublished data.

6-7.  Tuttle, J. H., et al., "Nitrogen Dioxide Formation in Gas Turbine
      Engines:  Measurements and Measurement  Methods," Combustion Science
      and Technology 9, 261 (1974)

6-8.  Johnson, G. M. and M. Y. Smith, "Nitrogen Dioxide Emissions from a
      Gas Turbine Power Station,"  International Clean Air Conference, The
      Clean Air Society of Australia and New  Zealand, Brisbane, Australia,
      May 15-19, 1978.
                                     61

-------