United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/3-89-11
May 1989
Air
Overview of the
Regulatory Baseline,
Technical Basis, and
Alternative Control Levels
for Particulate Matter (PM)
Emission Standards for
Small Steam Generating
Units

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                                       EPA-450/3-89-11
   OVERVIEW OF THE REGULATORY BASELINE,

 TECHNICAL BASIS, AND ALTERNATIVE CONTROL

LEVELS FOR PART1CULATE MATTER (PM) EMISSION

STANDARDS FOR SMALL STEAM GENERATING UNITS
            Emission Standards Division
         U.S. Environmental Protection Agency
            Office of Air and Radiation
       Office of Air Quality Planning and Standards
         Research Triangle Park, N.C. 27711
                 May 1989

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This report has been reviewed by the Emission  Standards Division of the
Office of Air Quality Planning and Standards,  EPA,  and approved for
publication.  Mention of trade names or commercial  products is not intended
to constitute endorsement or recommendation  of use.   Copies of the report
are available through the Library Service  Office  (MD-35),  U.S. Environmental
Protection Agency, Research  Triangle Park, N.C.   27711, or from National
Technical Services, 5285 Port Royal  Road,  Springfield, Virginia  22161.
                                     ii

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                              TABLE OF CONTENTS
Section                                                                Page
  1.0     INTRODUCTION 	    1
  2.0     SUMMARY	    2
  3.0     OIL PM EMISSIONS AND CONTROL TECHNIQUES 	    6
          3.1  REGULATORY BASELINE EMISSION LEVEL 	    6
          3.2  MEDIUM AND VERY LOW SULFUR/LOW ASH OIL	    7
          3.3  WET FLUE GAS DESULFURIZATION SYSTEMS	    8
          3.4  ELECTROSTATIC PRECIPITATORS  	   10
          3.5  ALTERNATIVE CONTROL LEVELS   .	10
  4.0     COAL PM EMISSIONS AND CONTROL TECHNIQUES	14
          4.1  REGULATORY BASELINE EMISSION LEVEL  	    14
          4.2  DOUBLE MECHANICAL COLLECTORS 	   15
          4.3  SIDESTREAM SEPARATORS	16
          4.4  WET FLUE GAS DESULFURIZATION SYSTEMS	18
          4.5  FABRIC FILTERS	18
          4.6  ELECTROSTATIC PRECIPITATORS  	   21
          4.7  ALTERNATIVE CONTROL LEVELS 	   23
  5.0     WOOD PM EMISSIONS AND CONTROL TECHNIQUES	25
          5.1  REGULATORY BASELINE EMISSION LEVEL   	   25
          5.2  DOUBLE MECHANICAL COLLECTORS   	   25
          5.3  WET SCRUBBERS	26
          5.4  ELECTROSTATIC PRECIPITATORS  	   28
          5.5  ALTERNATIVE CONTROL LEVELS 	   28
  6.0     REFERENCES	30
                                      iii

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LIST OF TABLES
Tables
2-1
2-2

3-1

3-2

4-1

4-2

4-3

4-4

5-1

5-2


SO, ALTERNATIVE CONTROL LEVELS FOR SMALL OIL- AND
COAL-FIRED BOILERS 	
PM ALTERNATIVE CONTROL LEVELS FOR SMALL OIL-, COAL-, AND
WOOD-FIRED BOILERS 	
PARTICULATE EMISSIONS FROM SO, WET SCRUBBERS APPLIED TO
RESIDUAL OIL-FIRED BOILERS. .* 	
SUMMARY OF PARTICULATE EMISSION TEST DATA FOR ELECTROSTATIC
PRECIPITATORS APPLIED TO OIL-FIRED BOILERS 	
PM EMISSIONS DATA FOR SIDESTREAM SEPARATORS APPLIED TO
SMALL COAL-FIRED BOILERS 	
PM EMISSIONS DATA FOR WET SCRUBBERS APPLIED TO COAL- FIRED
BOILERS 	
PM EMISSIONS DATA FOR FABRIC FILTERS APPLIED TO COAL-FIRED
BOILERS 	
PM EMISSIONS DATA FOR ELECTROSTATIC PRECIPITATORS APPLIED
TO COAL-FIRED BOILERS 	 	
PM EMISSIONS DATA FOR WET SCRUBBERS APPLIED TO WOOD-FIRED
BOILERS 	
SUMMARY OF PARTICULATE EMISSION TEST DATA ON WOOD-FIRED
BOILERS CONTROLLED WITH ESPS AND EGBS 	
Pag
3

4

9

11

17

19

20

22

27

?9
       iv

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                             1.0   INTRODUCTION

     This report provides an overview of the regulatory baseline, technical
basis, and alternative control  levels available for developing new source
performance standards (NSPS) limiting particulate matter (PM) emissions from
small steam generating units (i.e., boilers).  Small boilers are defined as
industrial-commercial-institutional steam generating units having heat input
capacities of 29 MW (100 million Btu/hour) or less.
     Many PM control techniques were considered for the purpose of
evaluating alternative PM emission standards for small  boilers.  Detailed
discussions of the design and operating principles of these techniques can
be found in the report entitled "Small  Steam Generating Unit Characteristics
and Emission Control Techniques,"  and  References 2 and 3.
     This report discusses the quantity of PM emissions generated and the
technical feasibility of controlling those emissions from boilers with heat
input capacities of 29 MW (100 million  Btu/hour) and less.  The uncontrolled
PM emissions from the combustion of natural gas in small steam generating
units are very low.  Uncontrolled PM emission levels of less than 9 ng/J
(0.02 Ib/million Btu) heat input are typical of natural gas-fired steam
generating units.  Because of these low uncontrolled PM emission levels, the
application of any type of PM control technology to small natural gas-fired
steam generating units would result in  unreasonable costs for little or no
air quality benefit.  Consequently, no  further consideration was given to
the development of standards to limit PM emissions from natural gas-fired
units.

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                                2.0   SUMMARY

     Particulate matter emissions from oil combustion may be correlated with
oil sulfur content.  Such correlations Indicate that reductions in PM
emissions are a secondary benefit associated with reducing emissions of S02
through the combustion of low sulfur oils.  Unlike oil, PM emissions from
coal cannot be correlated to fuel sulfur content.  As a result, limiting SCL
emissions from coal combustion through the use of low sulfur coal has no
effect on PM emissions.  The use of flue gas desulfurization (F6D) systems
to limit SCL emissions from oil and coal combustors, however, also results
in reduced PM emissions.
     Consequently, alternative control levels for standards limiting
SCL emissions from oil and coal combustion can result in reductions in
PM emissions.  In focusing on alternative control levels for standards
limiting PM emissions from oil and coal combustion, therefore, any reduction
in PM emissions associated with alternative control levels for standards
limiting SOg emissions should be taken into account.  Thus, alternative
control levels for standards limiting PM emissions from oil and coal
combustion are considered in relation to alternative control levels for
standards limiting S02 emissions.
     Wood, unlike oil and coal, contains little or no sulfur.  In addition,
few, if any, mixed fuel-fired (i.e., coal/wood or oil/wood) boilers are
expected for this source category.  As a result, there is no need to
consider levels selected for SCL standards in considering alternative
control levels for standards limiting PM emissions from small wood-fired
boilers.
     The alternative control levels considered for standards limiting SCL
emissions from small oil- and coal-fired boilers are presented in Table 2-1.
The alternative control levels selected in this study for standards limiting
PM emissions from small oil-, coal-, and wood-fired boilers are presented in
Table 2-2.

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       TABLE 2-1.  S02 ALTERNATIVE CONTROL LEVELS FOR SMALL OIL- AND

                   COAL-FIRED BOILERS
                                SOEmission Standard
                               Basis
Oil-Fired Boilers

Regulatory baseline


Alternative Control Level 1


Alternative Control Level 2


Alternative Control Level 3


Coal-Fired Boilers

Regulatory baseline


Alternative Control Level 1


Alternative Control Level 2
    1,290 ng/J
(3.0 Ib/million Btu)

      690 ng/J
(1.60 Ib/million Btu)

      210 ng/J
(0.50 Ib/million Btu)

90% S02 reduction
     1,550 ng/J
(3.6 Ib/million Btu)

       520 ng/J
(1.2 Ib/million Btu)
                        High  sulfur  oil
                        Medium  sulfur  oil
                        Very low  sulfur oil
                        FGD
90%
        reduction
                        Medium sulfur  coal
                        Low sulfur  coal
FGD or FBCC
aType F - bituminous


 Type B - bituminous


CFGD = Flue Gas Desulfurization
 FBC = Fluidized Bed Combustion

SOURCE:  Reference 4.

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    TABLE 2-2.  PM ALTERNATIVE CONTROL LEVELS FOR SMALL OIL-, COAL-, AND
                             WOOD-FIRED BOILERS
                                    PM Emission Standard
                                  Basis3
Oil-Fired Boilers
Regulatory Baseline
Alternative Control Level A
Alternative Control Level B
Alternative Control Level C

Coal-Fired Boilers
Regulatory Baseline
< 8.7 MW (30 million Btu/hour)  190 ng/J (0.45 To/million Btu)  SMC
> 8.7 MW (30 million Btu/hour)  260 ng/J (0.60 ID/million Btu)  SMC
 95 ng/J (0.22 ID/million Btu)  HSO
 73 ng/J (0.17 ID/million Btu)  MSO
 43 ng/J (0.10 1 fa/mill ion Btu)  WS or VLSO
 22 ng/J (0.05 To/million Btu)  ESP
Alternative Control Level A
Alternative Control Level B
Alternative Control Level C
Alternative Control Level D
130 ng/J (0.30 To/million Btu)  DMC
 86 ng/J (0.20 To/million Btu)  SSS
 43 ng/J (0.10 To/million Btu)  SMC+WS
 22 ng/J (0.05 To/million Btu)  FF or SMC+ESP

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      TABLE 2-2.  PM ALTERNATIVE CONTROL LEVELS FOR SMALL OIL-, COAL-,
                       AND WOOD-FIRED BOILERS  (continued)
                                    PM Emission Standard
                                   Basis'
Wood-Fired Boilers

Regulatory Baseline

< 8.7 MW (30 million Btu/hour)
> 8.7 MW (30 million Btu/hour)

Alternative Control Level  A

Alternative Control Level  B
Alternative Control Level  C
190 ng/J (0.45 Ib/million Btu)  SMC
260 ng/J (0.60 ID/million Btu)  SMC

130 ng/J (0.30 In/million Btu)  DMC

 86 ng/J (0.20 To/million Btu)  SMC +  WS
                                (low
                                pressure
                                drop)

 43 ng/J (0.10 la/million Btu)  SMC +  ESP  or
                                SMC +  WS
                                (medium
                                pressure
                                drop)
  SMC = Single Mechanical Collector
  DMC - Double Mechanical Collector
  SSS = Sidestream Separator
   FF = Fabric Filter
  ESP - Electrostatic Precipitator
   WS = Wet Flue Gas Desulfurization System (or Wet Scrubber)
  HSO =» High Sulfur Oil
  MSO = Medium Sulfur Oil
 VLSO = Very Low Sulfur Oil

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                3.0   OIL PM EMISSIONS AND CONTROL TECHNIQUES

     Particulate matter emissions from oil combustion may be correlated with
oil sulfur content.   Such correlations indicate that reductions in PM
emissions are a secondary benefit associated with reducing emissions of S02
through the combustion of low sulfur oils.  Particulate matter emissions are
also reduced if FGD systems are used to reduce SO, emissions from oil
           c                                     t.
combustion.   As a result, standards limiting S0£ emissions from oil
combustion, either through combustion of low sulfur oils or the use of FGD
systems, result in reductions in PM emissions.
     In considering alternative control levels for standards to limit PM
emissions from oil combustion, the reductions in PM emissions associated
with alternative control levels for standards limiting S02 emissions from
oil combustion should be taken into account.  In focusing on alternative
control levels for PM standards, therefore, this report considers these
alternatives in relation to alternative control levels selected for SO-
standards.
     The emission control techniques considered for limiting PM emissions
from small oil-fired boilers were medium and very low sulfur/low ash oils,
wet FGD systems or wet scrubbers, and ESP's.  Fabric filters were not
considered because of the sticky nature of fly ash from oil combustion.
Mechanical collectors were not evaluated for oil-fired boiler applications
because they are considered ineffective in collecting the small particle
size of PM from oil firing.

3.1  REGULATORY BASELINE EMISSION LEVEL

     The regulatory baseline emission level is defined as the emission
level that new small boilers would be required to meet under existing State
implementation plans (SIP).  The national  average SIP PM emission limits for
small oil-fired boilers range from 130 to 190 ng/J (0.30 to 0.45 Ib/million
Btu), depending on boiler size.   These emission limits can generally be met
when firing high sulfur oil with no add-on controls.

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     This is consistent with  the regulatory baseline selected for assessing
alternative control levels for standards  limiting  SO- emissions from small
oil-fired boilers.  As discussed in Overview of the Regulatory Baseline,
Technical Basis, and Alternative Control  Levels for Sulfur Dioxide (SCL)
Emission Standards for Small  Steam Generating Units, the regulatory baseline
selected for small oil-fired  boilers corresponds to the firing of high
sulfur oil [with a sulfur content of 1,290 ng S02/J (3.0 Ib SO^/million
Btu)].8
     A review of the data from over 100 steam generating units that were
used to establish the correlation between fuel  oil  sulfur content and
emissions of PM from oil combustion presented in the manual, Compilation of
Air Pollutant Emission Factors (AP-42), indicates  that fuel oils having a
sulfur content of 1,290 ng S02/J (3.0 Ib  S02/million Btu) would be expected
to produce PM emissions at a  rate of about 95 ng PM/J (0.22 Ib PM/million
Btu).9  Consequently, 95 ng PM/J (0.22 Ib PM/million Btu) is selected as the
regulatory baseline for small  oil-fired boilers.

3.2  MEDIUM AND VERY LOW SULFUR/LOW ASH OIL

     As discussed in Reference 4, the use of medium and very low sulfur oil
serves as the basis for Alternative Control  Levels  1 and 2 for standards
limiting S02 emissions from small oil-fired boilers, respectively.
Alternative Control Level 1 is 690 ng S02/J (1.60  Ib S02/million Btu) based
on the firing of medium sulfur oil.  Alternative Control Level 2 is 210 ng
S02/J (0.50 Ib S02/million Btu) based on  the firing of very low sulfur oil.
     Emission test data were  collected using Reference Method 5 from 18
steam generating units with heat input capacities  ranging from 28 to 400 MW
(94 to 1,360 million Btu/hour).    When combusting  fuel  oils with a sulfur
content of 690 ng S02/J (1.60 Ib S02/million Btu)  or less, the PM emissions
were less than 73 ng/J (0.17  Ib/million Btu) heat  input.  In addition,  based
on the data from AP-42 discussed above, combustion  of oil with a sulfur
content of 690 ng S02/J (1.60 Ib S02/million Btu)  or less will produce PM
emissions of 56 ng/J (0.13 Ib/million Btu) or less.

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     Emission test data presented in Reference 11 indicate that firing oil
with a sulfur content of 210 ng S02/J (0.50 Ib S02/miTlion Btu) or less will
generate PM emissions of 43 ng/J (0.10 ID/million Btu) or less.  Based on
the data from AP-42 discussed above, combustion of oil with a sulfur content
of 210 ng S02/J (0.50 Ib SO-Xmillion Btu) or less will produce PM emissions
of 23 ng/J (0.054 Ib/million Btu) or less.
     Thus, firing medium sulfur oil (690 ng S02/J [1.60 Ib S02/million Btu])
will reduce PM emissions from small boilers to 73 ng/J (0.17 Ib/million Btu)
or less.  Similarly, firing very low sulfur oil [210 ng S02/J (0.50 Ib
SCL/million Btu)] will reduce PM emissions to 43 ng/J (0.10 Ib/million Btu)
or less.

3.3  WET FLUE GAS DESULFURIZATION SYSTEMS (WET SCRUBBERS)

     As discussed in Reference 4, the use of wet FGD systems serves as the
basis for Alternative Control Level 3 for standards limiting S02 emissions
from small oil-fired boilers.  Table 3-1 presents a summary of PM emissions
data collected from small oil-fired boilers controlled by wet FGD systems.
The boilers ranged in size from 7 to 17 MW (22 to 57 million Btu/hour) and
burned oil with sulfur contents ranging from 1.1 to 2.8 weight percent.
During the tests, the boilers operated at 70 to 106 percent of full load.
Measured S02 removal efficiencies for the scrubbers ranged from 85 to 99
percent.
     Particulate matter emissions from these FGD systems ranged from 13 to
56 ng/J (0.03 to 0.13 Ib/million Btu).  For 17 of the 18 tests, emissions
ranged from 13 to 43 ng/J (0.03 to 0.10 Ib/million Btu).  Only one test
resulted in PM emissions greater than 43 ng/J (0.10 Ib/million Btu); this
test was conducted on a boiler operating at a load in excess of design
capacity.  This test result, therefore, is not considered to be
representative of PM emissions from FGD systems operating under normal
conditions.
     All FGD systems listed above are wet scrubbers designed with a venturi
apparatus for PM control. . Therefore, wet FGD systems or wet scrubbers are
considered to be a demonstrated control technique for reducing PM emissions
from small oil-fired boilers to 43 ng/J (0.10 ID/million Btu) or less.

                                      8

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           TABLE 3-1.  PARTICULATE EMISSIONS FROM SO2 WET SCRUBBERS APPLIED TO RESIDUAL
                                        OIL-FIRED BOILERS (12)

Company
Chevron
GenA-1, Run 1
GenA-1, Run 3
GenA-1, Run 5
Gen A-1, Run 6
Gen C-50. Run 1
Gen C-50, Run 3
Union #12, Run 1
Union #12. Run 2
Union #23. Run 1
Union #23, Run 2
Union #24, Run 1

Union #30, Run 1

Union #33, 37, Run 2
Union #33, 37, Run 4
Union #33, 37, Run 6
Number
of
units
7
1
1
1
1
1
1
1
1
1
1
1
1
1
1
5
5
5
Boiler
capacity, MW
(million Btu/hr)
heat Input
15 (52) (b)
17(57)
17(57)
17(57)
17(57)
17(57)
17(57)
15 (50)
15 (50)
7(25)
7(25)
15 (50)
15 (50)
15 (50)
15 (50)
15 (50)
15 (50)
15 (50)
Scrubber
type
VS
SV
SV
SV
SV
SV
SV
HT
HT
Koch
Koch
And
And
HT
HT
Koch
Koch
Koch
Design
paniculate
control
efficiency
(%)
40
91
92
76
70
89
77
40
40
40
40
40
40
40
40
40
40
40
Fuel
sulfur
(wt. %)
1.10
1.10
1.10
1.10
1.10
2.80
2.80
1.65
1.65
1.46
1.46
1.46
1.46
1.34
1.34
1.14
1.14
1.14
SO2
removal
(%)
92.0
99.0
99.0
99.0
99.9
99.9
99.9
95
95
98
98
96
96
92
92
99
99
99
Test load
(percent
of design
capacity)
NA
86
83
70
80
104
106
92
90
91
92
87
84
90
92
90
90
89
Controlled
paniculate
emissions
(Ib/million Btu)
(a)
0.03
0.04
0.04
0.06
0.07
0.06
0.13
0.08
0.08
0.10
0.06
0.07
0.09
0.09
0.09
0.06
0.07
0.06
NA - Not available.
VS " Venturi Scrubber.
SV « Steam Venturi Eductor with Spray Tower.
HT a Heater Tech. Caustic Scrubber, Venturi.
Koch = Koch Caustic Scrubber, Tray Tower (3 trays).
And = Anderson 2000 Caustic Scrubber, Spray Baffle.
(a) Based on EPA Reference Method 5 (front half catch).
   Multiply Ib/million Btu by 430 for conversion to ng/J.
(b) Test load heat input.

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3.4  ELECTROSTATIC PRECIPITATORS

     Most of the PM emissions data available for ESPs applied to oil-fired
boilers were gathered in a study of utility boilers, but the technology is
directly transferable to small oil-fired boilers.    Electrostatic
precipitator performance depends primarily on the specific collection area
(SCA), which is the ratio of the total collection plate area to the
volumetric gas flow rate.  Because this parameter is a ratio, its
correlation to ESP performance is independent of boiler size; therefore,
data for ESPs on utility oil-fired boilers are representative of ESP
performance on small oil-fired boilers.
     Table 3-2 summarizes PM emissions data for ESPs applied to oil-fired
boilers.  During the tests, oils with sulfur contents ranging from 0.7 to
2.0 weight percent were fired.  The PM emissions ranged from 18 to 29 ng/J
(0.04 to 0.07 Ib/million Btu).  Information regarding SCA was available for
only one ESP listed in Table 3-2.  This unit had an SCA of 435 m2/l,000m3/s
       2
(133 ft /I,000 acfm) and serviced a boiler firing a 2.0 weight percent
sulfur oil.  During the test, PM emissions ranged from 18 to 21 ng/J (0.041
to 0.049 ID/million Btu).  The performance of the other units could not be
evaluated because their SCAs are not available.
     These data, however, indicate that an ESP with an SCA of at least
435 m2/l,000m3/s (133 ft /I,000 acfm) is capable of reducing PM emissions
from small oil-fired boilers to 22 ng/J (0.05 Ib/million Btu) or less.
Therefore, ESPs are considered to be a demonstrated control technique for
reducing PM emissions from small oil-fired boilers to 22 ng/J
(0.05 Ib/million Btu) or less.

3.5  ALTERNATIVE CONTROL LEVELS

     As mentioned above, alternative control levels for standards limiting
SO- emissions from oil-fired boilers will  achieve PM emission reductions.
Thus, alternative control levels considered for standards limiting PM
emissions from small oil-fired boilers should be discussed in relation to
alternative control levels for standards limiting S02 emissions.
                                      10

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                      TABLE 3-2. SUMMARY OF PARTICULATE EMISSION TEST DATA FOR
                    ELECTROSTATIC PRECIPITATORS APPLIED TO OIL-FIRED BOILERS (14)

Company
Polaroid Corp.
New Bedford
Boston Edison (b)
Mystic Station
Unit No. 7


Hartford Electric Light Co.
Middletown Station

Number
of
units
2
1
1
1
1
1
1
Boiler
capacity, MW
(million Btu/hr)
heat input
28 (94)
1610(5500)
1610(5500)
1610(5500)
328(1120)
322(1100)
328(1120)
Filterable
paniculate
emissions
(Ib/million Btu)
(a)
0.055
0.070
0.041 (d)
(0.01 2) (d)
0.045 (d)
(0.009) (d)
0.049 (d)
(0.014) (d)
0.070
0.057
0.067
Paniculate
control
efficiency
(%)
40
51
83 (e)
NA
69 (e)
NA
78 (e)
NA
NA
NA
NA
Fuel
(% sulfur)
0.7
0.7
2.0
2.0
2.0
2.0
2.0
2.0
1.95(f)
1.86(1)
1.79(f)
(% ash)
NA(c)
NA
0.08
0.08
0.09
0.09
0.10
0.10
0.09
0.07
0.07
Test load. MW
(million Btu/hr)
heat input
NA
NA
1630(5580)
1640(5590)
1610(5490)
NA
NA
NA
(a) Multiply Ib/milllon Btu by 430 for conversion to ng/J.
(b) Design SCA Is 435 square meters per 1000 cubic meters per second  (133 square feet per 1000 ACFM).
   The ESP Is a cold-side unit controlling a high sulfur, high vanadium residual oil.
(c) NA => Not available.
(d) Data collected with EPA Method 5 train with filter temperature of about 320 degrees F;
   following collection, filters were baked per EPA Method SB; results in parentheses are EPA Method 5B results.
(e) Efficiency calculation based on low temperature EPA Method 5  inlet and outlet data.
(f) Oil additives used to prevent boiler fouling and corrosion.

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     Alternative Control Level 1 for SOg is 690 ng/J (1.60 Ib /million Btu)
based on the firing of medium sulfur oil.  As discussed in Section 3.2, this
corresponds to PM emissions of 73 ng/J (0.17 Ib/million Btu) or less.
Particulate matter emissions could be reduced to a level of 43 ng/J
(0.10 Ib/million Btu) or less by applying a wet scrubber or by firing very
low sulfur oil.  Emissions of PM could be further reduced to a level of
22 ng/J (0.05 Ib/million Btu) by applying an ESP.
     Alternative Control Level 2 for S02 is 210 ng/J (0.50 ID/million Btu)
based on the firing of very low sulfur oil.  As discussed above, the
combustion of very low sulfur oil corresponds to PM emissions of 43 ng/J
(0.10 To/million Btu) or less.  Emission of PM could be reduced to 22 ng/J
(0.05) Ib/million Btu) by applying an ESP.
     Alternative Control Level 3 for SO- is 90 percent S02 emission
reduction based on the use of FGD systems.  As discussed in Section 3.3,
FGD systems on small oil-fired boilers can reduce PM emissions to 43 ng/J
(0.10 ID/million Btu) or less.  Further PM emission reductions could be
achieved, to a level of 22 ng/J (0.05 Ib/million Btu), by applying an ESP
upstream of the FGD system.
     As a result, an emission rate of 73 ng/J (0.17 ID/million Btu) is
selected as Alternative Control Level A for standards limiting PM emissions
from small oil-fired boilers.  This alternative control level, however, is
achieved as a secondary benefit of Alternative Control Level 1 for standards
limiting SCL emissions and would, in fact, impose no additional emission
control requirements.
     An emission rate of 43 ng/J (0.10 ID/million Btu) is selected as
Alternative Control Level B for standards limiting PM emissions.  This
alternative is based on application of wet scrubbers or wet FGD systems or
the firing of very low sulfur oil.  This alternative control level would
impose additional emission control requirements beyond those imposed by
Alternative Control Level 1 for standards limiting SO- emissions.  It would
not, however, impose any additional emission control requirements beyond
those imposed by Alternative Control Levels 2 and 3 for standards limiting
SCL emissions.
                                      12

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     An emission rate of 22  ng/J  (0.05  ID/million  Btu)  based on the use of
an ESP is selected as Alternative Control  Level  C  for standards limiting PM
emissions.  This alternative control  level  would impose additional emission
control requirement beyond those  imposed  by Alternative Control Levels 1, 2,
and 3 for standards limiting SO-  emissions.
                                      13

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               4.0   COAL PM EMISSIONS AND CONTROL TECHNIQUES

     Unlike oil, PM emissions from coal cannot be correlated to fuel sulfur
content.  As a result, limiting SO- emissions from coal combustion through
the use of low sulfur coal has little, if any, effect on PM emissions.  The
use of FGD systems to limit SO- emissions from coal combustion, however,
does result in reduced PM emissions.
     Consequently, alternative control levels for standards limiting SO-
emissions from coal combustion can also result in reductions in PM
emissions.  In focusing on alternative control levels for standards limiting
PM emissions from coal combustion, therefore, any reduction in PM emissions
associated with alternative control levels for standards limiting SO-
emissions should be taken into account.  Thus, as with oil, alternative
control levels for standards limiting PM emissions from coal combustion are
considered in relation to alternative control levels for standards limiting
S02 emissions.
     The emission control techniques considered for limiting PM emissions
from small coal-fired boilers include double mechanical collectors,
sidestream separators, wet FGD systems or wet scrubbers, fabric filters, and
ESPs.

4.1  REGULATORY BASELINE EMISSION LEVEL

     The national average SIP emission limits for PM emissions from coal-
fired boilers range from 140 to 200 ng/J (0.33 to 0.46 Ib/million Btu).  The
PM control system typically used to meet these emission limits is a single
mechanical collector.  Mechanical collection is a well-established
technology using centrifugal separation to remove particles from a gas
stream.  Mechanical collectors have been widely used for years to control PM
emissions from steam generating units firing coal.  More recently, they have
been used as flue gas precleaning devices located upstream of more efficient
PM control devices.'
     Based on emissions test data in Reference 3, however, single mechanical
collectors are unable to maintain these low emission levels over time.  With
                                      14

-------
time, single mechanical  collector performance  deteriorates and PM emissions
increase.  The test data in  Reference  3  indicate  that  emission levels of
260 ng/J (0.60 Ib/million Btu)  for spreader stokers  and 190 ng/J
(0.45 ID/million Btu)  for underfeed stoker coal-fired  boilers are more
representative of long-term  mechanical collector  performance on these boiler
types.  Underfeed stokers are predominant  in the  2.9 to 8.7 MW (10 to
30 million Btu/hour) size range while  spreader stokers are most prevalent
above this size range.   Thus,  regulatory baseline PM emission levels of
190 ng/J (0.45 lb/ million Btu) and 260  ng/J (0.60 Ib/million Btu) were
selected for small coal-fired boilers  of less  than 8.7 MW (30 million
Btu/hour) and greater than or equal to 8.7 MW  (30 million Btu/hour),
respectively.

4.2  DOUBLE MECHANICAL COLLECTORS

     Most mechanical collectors consist  of multiple  small cyclone collectors
connected in a parallel  arrangement (multitube cyclone).   A variation of
this technology consists of  two mechanical collectors  connected in series.
This latter configuration is referred  to as a  double mechanical collector
(DMC).  This arrangement typically achieves lower PM emission levels than a
single mechanical collector.
     Although double mechanical collectors will reduce PM emissions from
coal combustion, they are relatively ineffective  for collection of PM with
mean diameters smaller than  10 microns (PM,Q). These  particle sizes,
however, are in the inhalable range and  have the  greatest potential for
adverse health impacts.
     To maintain the collection efficiency of  double mechanical collectors,
regular maintenance is required.     This is because  the performance of
mechanical collectors generally deteriorates with age  due to potential air
leakage into the ductwork and erosion  of the internal  structure by abrasive
fly ash.  Air leakage and erosion of internal  structures  tend to disturb the
cyclonic flow pattern,  which is vital  to double mechanical  collector
performance.  Air leakage may also cause re-entrainment of PM previously
collected.  In both cases, the PM control  performance  is  significantly
                                      15

-------
reduced.  As a result, annual emission tests together with repairs or
maintenance are necessary to ensure optimum double mechanical collector
performance over time.
     To assess the performance of double mechanical collectors on coal-fired
boilers, PM emissions data from nine sites were reviewed.    These data were
gathered using EPA Method 5 procedures.  The boilers ranged in size from 15
to 60 MW (60 to 206 million Btu/hour) and were operated at 33 to 100 percent
of full load during the tests.  Analyses of the coal fired in seven of these
boilers showed ash contents ranging from 4.8 to 9.5 weight percent and
sulfur contents ranging from 470 to 600 ng S02/J (1.1 to 1.4 Ib SO^/million
Btu).  Fuel analyses were not available for the remaining two sites.  The
average PM emissions ranged from 77 to 130 ng/J (0.18 to 0.29 Ib/million
Btu).  Thus, double mechanical collectors are considered to be a
demonstrated control technique for reducing PM emissions from boilers firing
low sulfur coal to 130 ng/J (0.30 Ib/million Btu) or less.  However, the
boiler owner/operator must limit the ash content of the coal fired to
approximately 10 weight percent or less.

4.3  SIDESTREAM SEPARATORS

     A sidestream separator is a mechanical collector from which a
slipstream or "sidestream" of flue gas is routed to a small fabric filter.
In most cases, about 20 percent of the total flue gas volume passes through
the fabric filter, although in some cases it may approach 50 percent of the
total gas stream.  Because a sidestream separator includes a mechanical
collector, the same potential exists for deterioration of performance with
age, as discussed for double mechanical collectors in Section 4.2.  Thus,
regular maintenance and annual emissions testing are required to ensure
optimum PM control performance.
     Table 4-1 presents PM emissions data from eight stoker boilers ranging
in size from 9 to 29 MW (31 to 100 million Btu/hour) and retrofitted with
sidestream separators.  The boilers operated at loads ranging from 68 to
108 percent of full capacity under relatively constant load conditions.   The
percent of total flow sent to the baghouse varied from 15 to 51 percent.
Coal ash content ranged from 4.3 to 10.1 weight percent.  Particulate matter

                                      16

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               TABLE 4-1. PM EMISSIONS DATA FOR SIDE STREAM SEPARATORS APPLIED TO
                                  SMALL COAL-FIRED BOILERS (17)


Plant
Gen Motors (ODD)
Gen Motors (EEE-1)
Gen Motors (GGG)
Gen Motors (CCC)
Gen Motors (EEE-3)
Gen Motors (BBB-3)
Gen Motors (FFF)
Milliken & Co.
Boiler
capacity, MW
(million Btu/hr)
heat Input
15 (50)
15 (50)
20(70)
23 (80)
18(60)
18(60)
29 (100)
9(31)


percent
ash
9.7
9.0
4.3
10.1
8.8
7.8
6.1
7.8
Fuel

percent
sulfur
0.8
1.8
0.9
0.8
2.1
0.8
1.7
1.3


heating value
(Btu/lB) (a)
12.900
12,400
13.700
11.400
12,400
13.100
13,100
13.200
Test load
range
(percent
of design
capacity)
68
84-93
78-80
71-80
99-105
97-108
85-97
100

Boiler
type (b)
SS
SS
SS
SS
SS
SS
SS
SS
Controlled
paniculate
emissions
(Ib/million Btu)
(c)
0.120
0.120
0.120
0.130
0.142
0.165
0.156
0.120
Percent
of flow
to
baghouse
16
37
30
31
51
17
15
NA(d)
(a) Multiply Btu/lb by 2.323 for conversion to kJ/kg.
(b) SS = Spreader stoker.
(c) Multiply Ib/million Btu by 430 for conversion to ng/J.
(d) NA = Not available.

-------
emissions ranged from 52 to 73 ng/J (0.12 to 0.17 ID/million Btu).
Therefore, sidestream separators are considered to be a demonstrated control
technique for reducing PM emissions from small coal-fired boilers to 86 ng/J
(0.20 ID/million Btu} or less.  However, as discussed above for dual
mechanical collectors, the boiler owner/operator must limit the ash content
of the coal fired to approximately 10 weight percent or less.

4.4  WET FLUE GAS DESULFURIZATION SYSTEMS (WET SCRUBBERS)

     Emission tests, summarized in Table 4-2, were available for three wet
                                                         18
FGD systems servicing coal-fired spreader stoker boilers.    The boilers
ranged from 37 to 69 MW (125 to 236 million Btu/hour) heat input and were
operated at loads ranging from 73 to 92 percent of full load during the
tests.
     All three wet scrubbers were dual alkali FGD systems designed with
venturi devices for combined PM and S02 control and were preceded by
mechanical collectors.  The scrubbers were operated at pressure drops
ranging from 1.9 to 4.8 kPa (7.5 to 19.3 inches of water).  The coals fired
during the tests had ash contents ranging from 4.4 to 11.4 weight percent
and sulfur contents ranging from 950 to 1,900 ng S02/J (2.2 to 4.4 Ib
SCL/million Btu).  The tests were conducted according to EPA Method 5 with
high sample box temperatures.  Particulate matter emissions ranged from 30
to 43 ng/J (0.07 to 0.10 Ib/million Btu).  Therefore, wet FGD systems or wet
scrubbers are considered to be a demonstrated control technique for reducing
PM emissions from small coal-fired boilers to 43 ng/J (0.10 To/million Btu)
or less.

4.5  FABRIC FILTERS

     Table 4-3 presents PM emissions test data, boiler size, and fuel
specifications for five coal-fired boilers and two fluidized bed combustion
(FBC) units equipped with fabric filters.  These data show PM emissions from
fabric filters ranging from 4.1 to 15 ng/J (0.010 to 0.035 To/million Btu).
The boilers ranged in size from 13 to 59 MW (48 to 208 million Btu/hour) and
were operated at loads ranging from 71 to 100 percent of full capacity.  For

                                      18

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                   TABLE 4-2.  PM EMISSIONS DATA FOR WET SCRUBBERS APPLIED TO
                                    COAL-FIRED BOILERS (18)


Site
Plant LL
Boiler #19
Plant LL
Boiler #20
Plant AAA

Bolter
capacity, MW
(million Btu/hr)
heat Input
69 (236)

69 (236)

37(125)
Operating
pressure
drop, Boiler
Scrubber kPa load
type (a) (Inches water) (%)
VS 4.8(19.3) 73

VS 4.3 (17.3) 85-91

MVT 1.9 (7.5) 92

Coal
sulfur
content
(wt. %)
2.6

2.5

1.3

Coal
ash
content
(wt.%)
11.4

10.4

4.4
Controlled
particulate
emissions
(Ib/million Btu)
(b)
0.10

0.07

0.08
(a) VS - Venturl scrubber, MVT - multiventuri tray scrubber.
(b) Multiply Ib/million Btu by 430 for conversion to ng/J.

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ro
o
                                        TABLE 4-3. PM EMISSIONS DATA FOR FABRIC FILTERS APPLIED TO
                                                           COAL-FIRED BOILERS (19)

Plant
DuPont(EE-2)
Formica (J2-4)
DuPont (EE-4)
DuPont (EE-5)
SOHIO
World Carpets
California Portland
Boiler
capacity, MW
(million Btu/hr)
heat Input
19(64)
19(65)
37(125)
45(181)
33(115)
13 (48)
59 (208)

percent
ash
6.9
6.9
7.0
6.5
12.3
8.3
8.8
Fuel
percent
sulfur
2.8
0.8
2.6
2.9
3.6
0.6
0.4

heating value
(Btu/lb) (a)
13,600
NA(d)
13,500
13,800
11,900
13.700
12,200
Test load
range
(percent
of design
capacity)
98-100
84-96
77-78
96
71
74
99
Controlled
paniculate
„ ,. emissions
Boiler (ib/million Btu)
type(b) (c)
SS
SS
SS
SS
FBC
SS
CFB
0.015
0.033
0.010
0.028
0.019
0.016
0.035
Air/cloth ratio
(ACFM/sqft)
design
3.4
2.5
3.7
3.7
NA
NA
NA
actual
3.4
2.3
2.9
3.6
NA
NA
NA
               (a) Multiply Btu/lb by 2.323 for conversion to kJ/kg.
               (b) SS o Spreader stoker, FBC - Fluidized bed combustor, CFB <
               (c) Multiply Ib/million Btu by 430 for conversion to ng/J.
               (d) NA » Not available.
Circulating fluidized bed combustor.

-------
the four coal-fired spreader  stoker  boilers,  the  fabric filters were
operated with  air-to-cloth  (A/C)  ratios  of 0.7  to 1.1  meters per minute
(m/min) (2.3 to 3.6 feet per  minute  [ft/min]).  Coal  ash contents for all
the boilers ranged from 6.5 to  12.3  weight percent.
     The boiler design types  included  in Table  4-3 are spreader stoker
boilers, a bubbling bed FBC unit,  and  a  circulating  bed F6C unit.  Boiler
sizes range from 13 to 59 MW  (48  to  208  million Btu/hour).   Fabric filters
reduced PM emissions from each  of these  boilers to less than 22 ng/J
(0.05 Ib/million Btu).  These data indicate that  fabric filter performance
is not significantly affected by  boiler  design  type  or size.  Thus, fabric
filters are considered to be  a  demonstrated control  technique for reducing
PM emissions from small coal-fired boilers to 22  ng/J  (0.05 Ib/million Btu)
or less.

4.6  ELECTROSTATIC PRECIPITATORS

     Table 4-4 presents PM  emission  test data from ESPs on  coal-fired
boilers ranging from 27 to  110  MW (92  to 375 million  Btu/hour) in size.  As
discussed in Section 3.4, ESP performance is primarily dependent on SCA;
thus, these data are also representative of ESPs  applied on small coal-fired
boilers.  The ash content of  the  coals burned ranged  from 5.4 to 12.0 weight
percent.  All  tests were conducted using EPA Method  5  and resulted in PM
emissions ranging from 3 to 19  ng/J  (0.006 to 0.044  Ib/million Btu).
     Four tests were conducted  on cold-side ESPs  (i.e., located downstream
of the air preheater) and two tests  were performed on  a hot-side ESP (i.e.,
located upstream of the air preheater).   Operating SCAs of  the cold-side
ESPs ranged from 419 to 1,300 m2/l,000 m3/s (128  to  397 ft2/!,000 acfm); the
hot-side ESP operated at SCAs of  1,770 and 2,080  m2/l,000 m3/s (542 and
634 ft2/!,000 acfm).
     All the emission tests shown in Table 4-4  were  conducted on boilers
firing coals with sulfur contents of 1.0 weight percent sulfur or less,
except for the Monsanto K7  boiler.   A  larger collection area is generally
required to achieve a given PM  collection efficiency on low sulfur
                                                      21
coal-fired units than on high sulfur coal-fired units.    Thus, the emission
control levels shown in Table 4-4 would  be achievable  on  boilers firing high

                                      21

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ro
ro
                                TABLE 4-4. PM EMISSIONS DATA FOR ELECTROSTATIC PRECIPITATORS APPLIED TO
                                                          COAL-FIRED BOILERS (19)


Plant
Monsanto (K-7)
Monsanto (K-8)
Monsanto (K-9)
KVB Plant P
KVB Plant N (f)
KVB Plant N (f)
Boiler
capacity, MW
minion Diu/nr)
heat Input
27 (92)
35(120)
46(156)
73 (250)
110(375)
110(375)


percent
ash
12.0
11.2
11.4
6.6
8.3
5.4
Fuel

percent
sulfur
NA(e)
1.00
0.57
0.73
0.54
0.63


heating value
(Btu/lb) (a)
12.500
12,500
11,400
13,100
10,200
10,600
Test load
range
(percent
of design
capacity)
103-106
93-98
99-102
87-89
76
52-59

Honor
type (b)
SS
SS
SS
SS
SS
SS
Controlled
paniculate
emissions
Specific collection area
(sq ft/1 000 ACFM)
(d)
(Ib/million Btui . ,
(c) design
0.007
0.006
0.012
0.021
0.044
0.018
132
156
128
349
344
344
operating
128
160
128
397
542
634
               (a) Multiply Btu/lb by 2.323 for conversion to kJ/kg.
               (b) SS = Spreader stoker.
               (c) Multiply Ib/mlllion Btu by 430 for conversion to ng/J.
               (d) Multiply sq ft/1000 ACFM by 3.2729 for conversion to square meters per 1000 cubic meters per second.
               (e) NA - Not available.
               (f) All tests done on a hot side ESP.

-------
sulfur coal  with SCAs equal  to  or  less  than  those  shown.
     The emission tests indicate that a cold-side  ESP with an SCA of at
least 1,310 m2/l,000 m3/s (400  ft2/!,000 acfm)  is  capable of achieving PM
emission levels ranging from 3  to  19 ng/J (0.006 to  0.044 Ib/million Btu) on
small boilers firing low sulfur coal.   A hot-side  ESP with an SCA of at
least 2,090 m2/l,000 m3/s (640  ft2/!,000 acfm)  could achieve emission levels
ranging from 7 to 19 ng/J (0.018 to 0.044 Ib/million Btu) on small boilers
firing low sulfur coal.  Therefore, ESPs are considered to be a demonstrated
control technique for reducing  PM  emissions  from coal-fired boilers to
22 ng/J (0.05 Ib/million Btu) or less.

4.7  ALTERNATIVE CONTROL LEVELS

     As discussed above, in  some cases  alternative control levels selected
for standards limiting S02 emissions from small coal-fired boilers will also
result in PM emission reductions.  Consequently, alternative control levels
considered for standards limiting  PM emissions  should be discussed in
relation to alternative control levels  for SO-  standards.
     Alternative Control Level  1 for standards  limiting SO- emissions from
small coal-fired boilers is  520 ng/J (1.2 ID/million Btu) and is based on
the use of low sulfur coal.   Alternative control levels for S02 standards
based on the use of low sulfur  coal will  not affect  PM emissions.  Thus, the
PM emission levels associated with SO-  Alternative Control Level 1 are the
PM regulatory baseline emission level of 190 ng/J  (0.45 ID/million Btu) for
boilers of less than 8.7 MW  (30 million Btu/hour)  and 260 ng/J
(0.60 ID/million Btu) for boilers  of 8.7 MW  (30 million Btu/hour) or
greater.
     Particulate matter emissions  could be reduced to 130 ng/J (0.30 lb/
million Btu) or less for small  coal-fired boilers  using a double mechanical
collector.  Emissions could  also be reduced  to  86  ng/J (0.20 Ib/million Btu)
or less by using a sidestream separator or to 43 ng/J (0.10 Ib/million Btu)
or less by using a wet scrubber.   Particulate matter emissions could be
further reduced to a 22 ng/J (0.05 Ib/million Btu) or less by use of a
fabric filter or an ESP.
     Alternative Control Level  2 for standards  limiting SO- emissions from
small coal-fired boilers is  a 90 percent reduction is SO- emissions on a
                                     23

-------
continuous basis.  This level can be met by use of FGD or FBC systems.  As
discussed in Section 4.4, use of wet FGD systems will reduce PM emissions to
43 ng/J (0.10 Ib/million Btu) or less.  Particulate matter emissions can be
further reduced to 22 ng/J (0.05 lb/ million Btu) by installing a fabric
filter or an ESP upstream of the FGD system.
     Fluidized bed combustion units and lime spray dryers are almost always
designed with a fabric filter for PM control.  Therefore, if an FBC unit or
lime spray dryer is used to meet S02 Alternative Control Level 2, PM
emissions will be reduced to 22 ng/J (0.05 Ib/million Btu) or less.
     An emission rate of 130 ng/J (0.30 ID/million Btu) is selected as
Alternative Control Level A for standards limiting PM emissions from small
coal-fired boilers.  This alternative is based on the use of a double
mechanical collector.
     Similarly, emission rates of 86 ng/J (0.20 Ib/million Btu) and 43 ng/J
(0.10 Ib/million Btu) are selected as Alternative Control Levels B and C.
Alternative B is based on the use of a sidestream separator and
Alternative C is based on the use of a wet scrubber.
     These alternatives would impose additional emission control
requirements under Alternative Control Level 1 for S02 standards.  They
would, however, impose no additional emission control requirements under
Alternative Control Level 2.
     Finally, an emission rate of 22 ng/J (0.05 Ib/million Btu) is selected
as Alternative Control Level D for standards limiting PM emissions from
small coal-fired boilers.  This alternative is based on the use of an ESP or
a fabric filter.
     As with Alternatives A, B, and C, Alternative D would impose additional
emission control requirements under Alternative Control Level 1 for SO-
standards.  Unlike these other alternatives, however, it would also impose
additional emission control requirements under Alternative Control Level 2
for SO- standards if a wet FGD system were used to meet the 90 percent SO-
reduction requirement.  If, on the other hand, an FBC unit or a lime spray
dryer was used to meet the 90 percent S02 reduction requirement associated
with Alternative Control Level 2, this alternative for PM emissions would
also impose no additional emission control requirements.
                                      24

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                5.0  WOOD PM EMISSIONS AND CONTROL TECHNIQUES

      Wood, unlike oil and coal, contains little or no sulfur.  In
addition, few,  if any, mixed fuel-fired  (i.e., coal/wood or oil/wood)
                                              ??
boilers are expected for this source category. '  As a result, there  is no
need to consider levels selected for S02 standards in considering
alternative control  levels for PM emissions from small wood-fired boilers.
The control techniques considered for limiting PM emissions from small
wood-fired boilers include double mechanical collectors, wet scrubbers, and
ESPs.  Fabric filters were not considered because of the potential' fire
hazards associated with wood-firing applications.

5.1  REGULATORY BASELINE EMISSION LEVEL

       The national  SIP emission limits for PM emissions from small wood-
fired boilers range from 160 to 170 ng/J (0.37 to 0.40 Ib/million Btu).23
The PM control system generally used to meet these emission limits is a
single mechanical collector.  However, as with single mechanical  collectors
on coal-fired boilers, single mechanical collectors on wood-fired boilers
are unable to maintain these low emission levels over time.  Mechanical
collector performance deteriorates with time and PM emissions increase.
Thus, the regulatory baseline for small wood-fired boilers is selected to
be 190 ng/J (0.45 Ib/million Btu) for boilers smaller than 8.7 MW (30
million Btu/hr) and 260 ng/J (0.60 Ib/million Btu) for boilers greater than
or equal to 8.7 MW (30 million Btu/hr) to reflect single mechanical
collector performance on small wood-fired boilers over time.

5.2  DOUBLE MECHANICAL COLLECTORS

      As discussed above in Section 4.2 for coal-fired boilers,  double
mechanical collectors will  also reduce PM emissions from wood combustors.
However, they are relatively ineffective for PMjQ removal.  These particles
are in the inhalable range and have the greatest potential for adverse
health impacts.

                                     25

-------
     To assess the performance of double mechanical  collectors on wood-fired
                                                        24
boilers, PM emission data from four sites were reviewed.    The data
represent four compliance tests conducted using Reference Method 5
procedures.  The boilers ranged in size from 7.3 to  44 MW (25 to 150 million
Btu/hour) and were operated at 72 to 116 percent of  full load during the
tests.  Outlet PM emissions ranged from 35 to 92 ng/J (0.082 to
0.215 Ib/million Btu).
     These double mechanical  collectors were tested  at relatively high
boiler loads.  Mechanical collectors,  in general,  are not as effective at
low load conditions.  Thus, as with coal-fired boilers, double mechanical
collectors are considered to  be a demonstrated control technique for
reducing PM emissions from small  wood-fired boilers  to 130 ng/J
(0.30 Ib/million Btu) or less.

5.3  WET SCRUBBERS

     Table 5-1 presents PM emissions data from wood-fired boilers equipped
with wet scrubbers.  Particulate emissions range from 21 to 91 ng/J (0.048
to 0.212 Ib/million Btu).  All boilers shown are spreader stokers which
range in size from 16 to 67 MW (55 to 230 million  Btu/hr).  The PM control
systems consist of a mechanical collector followed by a wet scrubber.  The
boilers were operated at loads ranging from 47 to  103 percent of full load
during the tests.  Fly ash reinjection is employed at all sources except at
boilers AC1 and AC2.  All data were obtained using EPA Method 5.
     The data show that wet scrubbers operating at low pressure drops [0.4
to 3.4 KPa (1.5 to 13.5 inches water)] and preceded  by a mechanical
collector can reduce PM emissions to 86 ng/J (0.20 Ib/million Btu)  or less.
Wet scrubbers operating at medium pressure drops [(3.8 to 6.0 KPa (15 to 26
inches water)] and preceded by a mechanical  collector can reduce PM
emissions to 43 ng/J (0.10 Ib/million Btu) or less.   Therefore, low
pressures drop wet scrubbers  are considered demonstrated at 86 ng/J (0.20
Ib/million), whereas medium pressure drop wet scrubbers are considered
demonstrated at 43 ng/J (0.10 1 fa/million Btu).
                                      26

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                                         TABLE 5-1. PM EMISSIONS DATA FOR WET SCRUBBERS APPLIED TO
                                                            WOOD-FIRED BOILERS (25)
ro

Boiler
Number capacity, MW
of (million Btu/hr)
Plant units heat Input
Champion International (AB2)
Georgia Pacific (AC1)
Georgia Pacific (AC2)
Georgia Pacific (ADI)
Georgia Pacific (AG1)
Georgia Pacific (AM)
Georgia Pacific (API)
Georgia Pacific (AE1)
Georgia Pacific (AH1)
St. Joe Paper (AJ2) (f)
St. Joe Paper (AJ4) (f)
St. Joe Paper (AJ5) (f)
Boise Cascade (AA1)
St. Regis Paper (AK2)(f)
St. Regis Paper (AK3) (f)
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
32(108)
17/17
(57/57) (d)
16 (55)
18(61)
50 (170)
50 (170)
54(165)
54(185)
63 (215)
50 (170)
50 (170)
50 (170)
67 (230)
61 (210)
61 (210)
Scrubber
type
Imp
Imp
Imp
Ven
Ven
Ven
Imp
Ven
Ven
VTV
VTV
VTV
VTV
Ven
Ven
Fuel
Efficiency sulfur
(%) (wt. %)
NA
NA
NA
NA
NA
NA
NA
NA
NA
94
96
NA
NA
98
NA
NA - Not available.
Imp - Impingement
Ven «• Venturl
VTV = Variable Throat Venturl
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.03
0.01
NA
NA
0.04
0.17
Fuel
ash
(wt. %)
NA
NA
NA
NA
NA
NA
NA
NA
NA
2.2
1.9
NA
2-8 (g)
1.7
4.2
Test load Average Controlled
(percent operating particulate
of design pressure emissions
capacity) drop (Ib/million Btu)
(a) (inches water) (c)
79
63
47
73 (e)
103
86
72
85
65
91
95
91
95
94
100
6-8
6-8
6-8
6-8
6-8
6-8
6-8
6-8
6-8
8
13.5
15.2
18
20
26
0.068
0.182
0.170
0.182
0.169
0.212
0.100
0.131
0.148
0.104
0.137
0.057
0.048
0.074
0.063
(a) Average value during testing.
(b) Multiply Inches of water by 0.2486 for conversion to kPa.
(c) Multiply Ib/milllon Btu by 430 for conversion to ng/J.
(d) Two boilers which exhaust into a single wet scrubber.
                                                                           (e) Estimated, based on mass emission rate and F-factor.
                                                                           (f) EPA Method 5 data acquired on EPA tests.
                                                                           (g) These data did not come from an analysis done during emission testing.
                                                                              They were obtained from industry sources and are representative of
                                                                              the typical fuel burned at this facility.

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5.4  ELECTROSTATIC PRECIPITATORS

     Table 5-2 presents PM emission test data for ESPs applied on wood-fired
boilers that range in size from 50 to 202 MW (170 to 690 million Btu/hour).
As discussed above for oil and coal combustion,  ESP performance on large
wood-fired boilers is also representative of ESP performance on small
wood-fired boilers.  All boilers are spreader stokers firing wood or
wood/coal mixtures.  The boilers operated at 25  to 69 percent of full load
during the tests.  A mechanical collector is located upstream of each ESP;
fly ash reinjection was used during all  tests.   The PM emission test results
ranged from 18 to 31 ng/J (0.042 to 0.072 Ib/million Btu).   The operating
SCAs ranged from 752 to 1,480 m2/l,000 m3/s (230 to 453 ft2/!,000 acfm).
     The emission test data indicate that an ESP with an SCA of at least
     2
980 m /1,000 acfm) and preceded by a mechanical  collector is capable of
achieving a PM emission level of 43 ng/J (0.10  Ib/million Btu) heat input or
less on small wood-fired boilers.  Therefore, ESPs are considered to be a
demonstrated control technique for reducing PM  emissions from wood-fired
boilers to 43 ng/J (0.10 ID/million Btu) heat input or less.

5.5  ALTERNATIVE CONTROL LEVELS

     Alternative Control Level A for wood-fired  boilers is  selected as
130 ng/J (0.30 Ib/million Btu) heat input based  on the use  of a double
mechanical collector.  Alternative Control  Level B is selected as 86 ng/J
(0.20 Ib/million Btu) heat input, which can be met by using a wet scrubber
operated at a low pressure drop and preceded by  a mechanical collector.
Finally, Alternative Control Level C for wood-fired boilers is selected as
43 ng/J (0.10 Ib/million Btu) heat input.  This  level can be achieved by
using a mechanical collector combined with  either an ESP or a wet scrubber
operated at a medium pressure drop.
                                     28

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                                 TABLE 5-2.  SUMMARY OF PARTICULATE EMISSION TEST DATA ON WOOD-FIRED BOILERS
                                                         CONTROLLED WITH ESPS AND EGBS (23)
ro
ID


Plant
Champion International Coop (BA1)
Westvaco Bleached Board (BI1) (d)
Westvaco Bleached Board (BB1)
Weyerhaeuser Co. (BE2) (g)
Weyerhaeuser Co. (BE3) (I)
Weyerhaeuser Co. (BE4) (I)
Weyerhaeuser Co. (BES) (I)
Weyerhaeuser Co. (BE6) (i)

Control
device
ESP
ESP
ESP
EGB
EGB
EGB
EGB
EGB
Boiler
capacity, MW
(million Btu/hr)
heat Input
50 (170)
108/147(370/500)
202 (690)
180(615)
180 (615)
180(615)
180(615)
180(615)
Fuel
%
ash
NA
3.4 (e)
4.8 (f)
9.4 (h)
3.8
3.8
4.8
4.8
%
sulfur
NA
0.3
NA
0.06
NA
NA
NA
NA
Test load
range
(percent
heating value of design
(Btu/lb) (a) capacity)
NA
10.750
8.250
8.270
8,970
8,910
8.780
8.830
66
25/25
69
96
101
116
95
107
Specific collection area
(sq ft/1 000 ACFM)
Boiler
type
SS
SS
SS
SS
SS
SS
SS
SS
(b)
design
177
296
298
NA
NA
NA
NA
NA
operating
230
320
453
6.00)
3.4(|)
4.0 (j)
5.60)
7.10)
Controlled
participate
emissions
Ib/million Btu)
(c)
0.072
0.042
0.057
0.027
0.025
0.024
0.039
0.051
         (a) Multiply Btu/lb by 2.323 for conversion to kJ/kg.

         (b) Multiply sq ft/1000 ACFM by 3.2729 for conversion to sq meters per 1000
         cubic meters per second.

         (c) Multiply Ib/million Btu by 430 for conversion to ng/J.

         (d) The flue gas from two boilers pass through Individual mechanical
         collectors. It is then combined into a single duct and split to enter a
         two-chamber ESP with two stacks. The test data and emission levels shown are
         the weighted average of both stacks.

         (e) Boiler burns low sulfur coal with the wood.  The analysis of the coal
         showed the following composition: moisture - 5.5%; ash (dry) -12.4%; sulfur
         (dry) - 0.86%.

         (f) These data did not come from an analysis done during emission testing.
         They were obtained from Industry sources and are representative of the typical
         fuel burned at this facility.

         (g) The EGB has three modules, each of which cleans one-third of the flue gas.
         Each module has a separate stack. The emission levels shown are the weighted
         average of all three stacks.
(h) At this facility, char from the first stage of the mechanical collector is
slurrled and separated by screens into large and small fractions.  The large
char is mixed with the hog fuel. These values represent an analysis of the
mixture of char and hog fuel.

(i) Emissions are from the outlet of module 3 of the EGB.

0) For EGB, this value is pressure drop in inches of water. Multiply inches
of water by 0.2468 for conversion to kPa.

NA a not available.

SS = Spreader Stoker.

ESP = Electrostatic Precipitator.

EGB = Electrostatic Gravel Bed Filter.

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                              6.0   REFERENCES

1.   U.S. Environmental Protection Agency.  Small Steam Generating Unit
     Characteristics and Emission Control Techniques.  Research Triangle
     Park, NC.  March 31, 1989.

2.   U.S. Environmental Protection Agency.  Nonfossil Fuel-Fired Industrial
     Boilers - Background Information.  Research Triangle Park, NC.
     Publication No. EPA-450/3-82-007.  March 1982.

3.   U.S. Environmental Protection Agency.  Fossil Fuel-Fired Industrial
     Boilers - Background Information.  Volume I.  Research Triangle Park,
     NC.  Publication No. EPA-450/3-82-006a.  March 1982.

4.   Overview of the Regulatory Baseline, Technical Basis, and Alternative
     Control Levels for Sulfur Dioxide (SO-) Emission Standards for Small
     Steam Generating Units.  U.S. Environmental Protection Agency, Research
     Triangle Park, NC.  EPA Publication No. EPA-450/3-89-12.  May 1989.

5.   Particulate Matter Emission from Residual Oil-Fired Boilers.  Prepared
     by Radian Corporation.  Prepared for U.S. Environmental Protection
     Agency, Research Triangle Park, NC.  June 4, 1984.  p. 2.

6.   Reference 5.  p. 9.

7.   Reference 1.

8.   Reference 4.  p. 4.

9.   U.S. Environmental Protection Agency.  Compilation of Air Pollution
     Emission Factors.  AP-42 Supplement No. 13.  Research Triangle Park,
     NC.  August 1982.

10.  GCA Corporation.  Particulate Emission Control Systems for Oil-Fired
     Boilers.  Prepared for the U. S. Environmental Protection Agency,
     Research Triangle Park, NC.  Publication No. 450/3-74-063,
     December, 1974.  pp. 68-74.

11.  Reference 10.

12.  Reference 1.

13.  Reference 3.  p. 4-43.

14.  Reference 1.

15.  Telecon.  Aul, E.F. (Radian Corporation), with Berst, A. (Zurn, Air
     Systems Division), December 8, 1987.  Costs for regular inspection and
     maintenance programs for mechanical collectors and sidestream
     separators.
                                      30

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16.  Memorandum from Waddell,  J.T.,  and E.F.  Aul,  Radian Corporation, to
     Maxwell, W.H., EPA/ISB.   January 15,  1988.   Performance of Dual
     Mechanical Collectors on  Small  Coal-  and Wood-Fired Boilers.

17.  Reference 1.

18.  U.S. Environmental  Protection Agency.   Fossil  Fuel-Fired Industrial
     Boilers - Background Information.   Volume 2.   Research Triangle Park,
     NC.  Publication No. EPA-450/3-82-006b.   March 1982.  pp. C-lll, C-114,
     C-115 and C-137.

19.  Reference 1.

20.  Reference 1.

21.  Reference 3.  p. 4-45.

22.  Memorandum.  Aul, E.F., Radian  Corporation,  to Maxwell, W.H. EPA/ISB.
     September 22, 1987.  Population Projection  for Small Mixed Fuel-Fired
     Steam Generating Units.   15 p.

23.  Reference 1.

24.  Memorandum from Frey, H.C.  and  J.T. Waddell,  Radian Corporation, to
     Copland, R.A. EPA/SOB.  February 28,  1989.   State Permitting Practices
     for Particulate Matter Emissions from  Small  Coal- and Wood-Fired
     Boilers.  30 p.

25.  Reference 1.

26.  Reference 1.
                                     31

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing]
  REPORT NO.
  EPA-450/3-89-11
                                                            3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE  _               , .    _
  Overview of the  Regulatory Baseline, Technical  Basis,
  and Alternative  Control  Levels for Particulate  Matter
  (PM) Emission  standards  for Small Steam  Generating Unit:
             5. REPORT DATE
               May  1989
             6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
                                                            8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
  Emission Standards  Division
  Office of Air Quality  Planning and Standards
  U.S. Environmental  Protection Agency
  Research Triangle Park,  North Carolina   27711
                                                            10. PROGRAM ELEMENT NO.
             11. CONTRACT/GRANT NO.
              68-02-4378
12. SPONSORING AGENCY NAME AND ADDRESS
  Office of Air Quality Planning and Standards
  Office of Air and  Radiation
  U.S. Environmental  Protection Agency
  Research Triangle  Park,  North Carolina   27711
                                                            13.jyPE OF REPORT AND PERIOD COVERED
                                                              FinaT
             14. SPONSORING AGENCY CODE
              EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
       This report provides  a summary of the  technical data used  in  developing
  proposed new source  performance standards  (NSPS)  for small industrial-commercial -
  institutional steam  generating units (small  boilers).  The report  focuses on
  particulate matter  (PM)  emissions from boilers  firing coal, oil, and  wood with heat
  input capacities of  100  million Btu/hour or less.  Conclusions  are drawn from the
  data regarding the performance of technologies  available to reduce PM emissions.
  Alternative control  levels are then chosen  based  on the conclusions drawn from
  the data.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                               b.lDENTIFIERS/OPEN ENDED TERMS  C. COSATI Field/Group
 Air Pollution
 Pollution Control
 Standards of Performance
 Steam Generating Units
   Industrial Boilers
   Small  Boilers
   Air Pollution Control
18. DISTRIBUTION STATEMENT

  Release unlimited
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