United States	Office of Air Quality
Environmental Protection Planning and Standards	EPA-450/3-89-11
Agency	Research Triangle Pa/kNC 27711	May 1989
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 PARTICULATE 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
1
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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.
i i

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TABLE OF CONTENTS
Section	Pass
1.0 INTRODUCTION 		1
2.0 SUMMARY		2
3.0 OIL PM EMISSIONS ANO 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 WOOO 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
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LIST OF TABLES
Tables	Page
2-1 SO- ALTERNATIVE CONTROL LEVELS FOR SMALL OIL- AND
COAL-FIRED BOILERS 	 3
2-2	PH ALTERNATIVE CONTROL LEVELS FOR SMALL OIL-, COAL-, AND
WOOD-FIRED BOILERS	 4
3-1	PARTICULATE EMISSIONS FROM SO, WET SCRUBBERS APPLIED TO
RESIDUAL OIL-FIRED BOILERS. /	 9
3-2	SUMMARY OF PARTICULATE EMISSION TEST DATA FOR ELECTROSTATIC
PRECIPITATORS APPLIED TO OIL-FIRED BOILERS 	 11
4-1	PM EMISSIONS DATA FOR SIDESTREAM SEPARATORS APPLIED TO
SMALL COAL-FIRED BOILERS 	 17
4-2 PM EMISSIONS DATA FOR WET SCRUBBERS APPLIED TO COAL-FIRED
BOILERS	19
4-3 PM EMISSIONS DATA FOR FABRIC FILTERS APPLIED TO COAL-FIRED
BOILERS	20
4-4	PM EMISSIONS DATA FOR ELECTROSTATIC PRECIPITATORS APPLIED
TO COAL-FIRED BOILERS 	 22
5-1	PM EMISSIONS DATA FOR WET SCRUBBERS APPLIED TO WOOO-FIRED
BOILERS	27
5-2 SUMMARY OF PARTICULATE EMISSION TEST DATA ON WOOD-FIRED
BOILERS CONTROLLED WITH ESPS AND EGBS 	 29
i v

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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-comnercial-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 lb/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.
1

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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 SO^
through the combustion of low sulfur oils. 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 no
effect on PM emissions. The use of flue gas desulfurization (FGD) systems
to limit SOg emissions from oil and coal combustors, however, also results
in reduced PM emissions.
Consequently, alternative control levels for standards limiting
SOg 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 SO^ 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 SOg 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 1s no need to
consider levels selected for SO^ standards in considering alternative
control levels for standards limiting PM emissions from small wood-fired
boilers.
The alternative control levels considered for standards limiting SO^
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.
2

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



SOg Emission Standard
Basi s
Oil-Fired Boilers




Regulatory baseline


1,290 ng/J
(3.0 lb/mill ion Btu)
High sulfur oi1
Alternative Control
Level
1
690 ng/J
(1.60 lb/million Btu)
Medium sulfur oil
Alternative Control
Level
2
210 ng/J
(0.50 lb/mill ion Btu)
Very low sulfur oi1
Alternative Control
Level
3
90% SO2 reduction
FGD
Coal-Fired Boilers




Regulatory baseline


1,550 ng/J
(3.6 lb/mil 1 ion Btu)
Medium sulfur coal3
Alternative Control
Level
1
520 ng/J
(1.2 lb/million Btu)
Low sulfur coal'5
Alternative Control
Level
2
90% SO2 reduction
FGD or FBCc
aType F - bituminous
''Type B - bituminous
CFGD - Flue Gas Desulfurization
FBC » Fluidized Bed Combustion
SOURCE: Reference 4.
3

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TABLE 2-2. PM ALTERNATIVE CONTROL LEVELS FOR SMALL OIL-, COAL-, AND
WOOD-FIRED BOILERS
PM Emission Standard	Basisa
Oil -Fired Boilers






Regulatory Baseline
95
ng/J
(0.22
1b/mi11 ion
Btu)
HSO
Alternative Control Level A
73
ng/J
(0.17
1b/mi11 ion
Btu)
MSO
Alternative Control Level B
43
ng/J
(0.10
lb/mill ion
Btu)
WS or VLSO
Alternative Control Level C
22
ng/J
(0.05
lb/mill ion
Btu)
ESP
Coal-Fired Boilers






Regulatory Baseline






< 8.7 MW (30 million Btu/hour)
> 8.7 MW (30 million Btu/hour)
190
260
ng/J
ng/J
(0.45
(0.60
lb/mill ion
lb/mi 11 ion
Btu)
Btu)
SMC
SMC
Alternative Control Level A
130
ng/J
(0.30
1b/mi11i on
Btu)
DMC
Alternative Control Level B
86
ng/J
(0.20
1b/mi11 ion
Btu)
SSS
Alternative Control Level C
43
ng/J
(0.10
lb/mill ion
Btu)
SMC+WS
Alternative Control Level D
22
ng/J
(0.05
lb/mill ion
Btu)
FF or SMC+ESP
4

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TABLE 2-2. PM ALTERNATIVE CONTROL LEVELS FOR SMALL OIL-, COAL-,
AND WOOD-FIRED BOILERS (continued)
PM Emission Standard	Basis3
Wood-Fired Boilers





Regulatory Baseline





< 8.7 MW (30 million Btu/hour)
> 8.7 MW (30 million Btu/hour)
190 ng/J
260 ng/J
(0.45
(0.60
1b/mi11 ion
1b/mi11 ion
Btu)
Btu)
SMC
SMC
Alternative Control Level A
130 ng/J
(0.30
lb/mil 1 ion
Btu)
DMC
Alternative Control Level B
86 ng/J
(0.20
lb/mill ion
Btu)
SMC + WS
(low
pressure
drop)
Alternative Control Level C
43 ng/J
(0.10
lb/mi 11 ion
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
5

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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 50^
through the combustion of low sulfur oils. Particulate matter emissions are
also reduced if FGD systems are used to reduce SO- emissions from oil
6
combustion. As a result, standards limiting SO^ emissions from oil
combustion, either through combustion of low sulfur oils or the use of FGO
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 SO2 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 lb/million
Btu), depending on boiler size.7 These emission limits can generally be met
when firing high sulfur oil with no add-on controls.
6

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This is consistent with the regulatory baseline selected for assessing
alternative control levels for standards limiting SOj emissions from small
oil-fired boilers. As discussed in Overview of the Regulatory Baseline,
Technical Basis, and Alternative Control Levels for Sulfur Dioxide (SO^)
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 SO-/J (3.0 lb S09/mi11ion
Btu) ].
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 SO2/J (3.0 lb SOj/million Btu) would be expected
to produce PM emissions at a rate of about 95 ng PM/J (0.22 lb PM/mi11ion
Btu).^ Consequently, 95 ng PM/J (0.22 lb 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 SO^ emissions from small oil-fired boilers, respectively.
Alternative Control Level 1 is 690 ng SOj/J (1.60 lb S02/million Btu) based
on the firing of medium sulfur oil. Alternative Control Level 2 is 210 ng
SO2/J (0.50 lb 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 SOg/J (1.60 lb SO^/million Btu) or less, the PM emissions
were less than 73 ng/J (0.17 lb/milHon Btu) heat input. In addition, based
on the data from AP-42 discussed above, combustion of oil with a sulfur
content of 690 ng SOg/O (1.60 lb SOj/million Btu) or less will produce PM
emissions of 56 ng/J (0.13 lb/million Btu) or less.
7

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Emission test data presented in Reference 11 indicate that firing oil
with a sulfur content of 210 ng St^/J (0.50 lb SO^/million 8tu) or less will
generate PM emissions of 43 ng/J (0.10 lb/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 lb S02/million Btu) or less will produce PM emissions
of 23 ng/J (0.054 lb/million Btu) or less.
Thus, firing medium sulfur oil (690 ng S02/J [1.60 lb S02/million Btu])
will reduce PM emissions from small boilers to 73 ng/J (0.17 lb/million Btu)
or less. Similarly, firing very low sulfur oil [210 ng S02/J (0.50 lb
S02/million Btu)] will reduce PM emissions to 43 ng/J (0.10 lb/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 lb/million Btu). For 17 of the 18 tests, emissions
ranged from 13 to 43 ng/J (0.03 to 0.10 lb/million Btu). Only one test
resulted in PM emissions greater than 43 ng/J (0.10 lb/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 lb/million Btu) or less.
8

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TABLE 3-1. PARTICULATE EMISSIONS FROM S02 WET SCRUBBERS APPLIED TO RESIDUAL
OIL-FIRED BOILERS (12)
Company
Number
of
units
Boiler
capacity, MW
(million Btu/hr)
heal Input
Scrubber
type
Design
particulate
control
efficiency
(%)
Fuel
sulfur
(wt. %)
S02
removal
(%)
Test load
(percent
of design
capacity)
Controlled
particulate
emissions
(lb/million Btu
(a)
Chevron
7
15 (52) (b)
VS
40
1.10
92.0
NA
0.03
Gen A-1, Run 1
1
17 (57)
SV
91
1.10
99.0
66
0.04
Gen A-1, Run 3
1
17 (57)
SV
92
1.10
99.0
83
0.04
Gen A-1, Run 5
1
17 (57)
SV
76
1.10
99.0
70
0.06
Gen A-1, Run 6
1
17(57)
SV
70
1.10
99.9
60
0.07
Gen C-50, Run 1
1
17(57)
SV
89
2.80
99.9
104
0.06
Gen C-50, Run 3
1
17 (57)
SV
77
2.80
99.9
106
0.13
Union 012, Run 1
1
15 (50)
HT
40
1.65
95
92
0.08
Union 012, Run 2
1
15 (50)
HT
40
1.65
95
90
0.08
Union 023, Run 1
1
7(25)
Koch
40
1.46
9B
91
0.10
Union 023, Run 2
1
7(25)
Koch
40
1.46
98
92
0.06
Union 024, Run 1
1
15(50)
And
40
1.46
96
87
0.07

1
15(50)
And
40
1.46
96
84
0.09
Union 030, Run 1
1
15(50)
HT
40
1.34
92
90
0.09

1
15 (50)
HT
40
1.34
92
92
0.09
Union 033, 37, Run 2
5
15 (50)
Koch
40
1.14
99
90
0.06
Union 033, 37, Run 4
5
15 (50)
Koch
40
1.14
99
90
0.07
Union 033, 37, Run 6
5
15 (50)
Koch
40
1.14
99
89
0.06
NA - Not available.	(a) Based on EPA Relerence Method 5 (front half catch).
VS - Venturl Scrubber.	Multiply Ib/mllllon Btu by 430 for conversion to ng/J.
SV - Steam Venturl Eductor with Spray Tower.	(b) Test load heat Input.
HT a Heater Tech. Caustic Scrubber, Venturl.
Koch - Koch Caustic Scrubber, Tray Tower (3 trays).
And = Anderson 2000 Caustic Scrubber, Spray Baffle.

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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 lb/million Btu). Information regarding SCA was available for
only one ESP listed in Table 3-2. This unit had an SCA of 435 m^/l»00OmVs
2
(133 ft /l,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 lb/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
2	3	2
435 m /1,000m /s (133 ft /l,000 acfm) is capable of reducing PM emissions
from small oil-fired boilers to 22 ng/J (0.05 lb/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 lb/million Btu) or less.
3.5 ALTERNATIVE CONTROL LEVELS
As mentioned above, alternative control levels for standards limiting
SO2 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 SO£ 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
Number
of
units
Boiler
capacity, MW
(million Blu/hr)
heal Input
Filterable
particulate
emissions
(Ib/mlllon Blu)
(a)
Particulate
control
efficiency
(%)
Fuel
(% sulfur)
(% ash)
Test load, MW
(million Blu/hr)
heat Input
Polaroid Corp.
2
28(94)
0.055
40
0.7
NA (c)
NA
New BBdfora

0.070
51
0.7
NA
NA
Boston Edison (b)
1
1610(5500)
0.041 (d)
83(e)
2.0
0.08
1630 (5560)
Mystic Station
UnH No. 7

(0.012) (d)
NA
2.0
0.08

1
1610(5500)
0.045 (d)
69 (e)
2.0
0.09
1640 (5590)



(0.009) (d)
NA
2.0
0.09


1
1610 (5500)
0.049 (d)
78 (e)
2.0
0.10
1610(5490)



(0.014) (d)
NA
2.0
0.10

Hartford Electric Light Co.
1
328 (1120)
0.070
NA
1.95 (f)
0.09
NA
Mlddletown Station
1
322(1100)
0.057
NA
1.86 (f)
0.07
NA

1
328(1120)
0.067
NA
1.79 (0
0.07
NA
(a)	Muliply Ib/mllllon Blu by 430 for conversion to ng/J.
(b)	Design SCA Is 435 square meters per 1000 cubic meters per second 1133 square (eel per 1000 ACFM).
The ESP is a cold-side unh controlling a high 6ulfur, high vanadium residual oil.
(c)	NA = Not available.
(d)	Data collected with EPA Method 5 train with filter temperature ol about 320 degrees F;
following collection, filters were baked per EPA Method 5B; 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 SO2 is 690 ng/J (1.60 lb /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 lb/million Btu) or less.
Particulate matter emissions could be reduced to a level of 43 ng/J
(0.10 lb/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 1b/m111ion Btu) by applying an ESP.
Alternative Control Level 2 for SO£ is 210 ng/J (0.50 lb/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 lb/million Btu) or less. Emission of PM could be reduced to 22 ng/J
(0.05) lb/million Btu) by applying an ESP.
Alternative Control Level 3 for SO2 is 90 percent SC^ 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 lb/million Btu) or less. Further PM emission reductions could be
achieved, to a level of 22 ng/J (0.05 lb/million Btu), by applying an ESP
upstream of the FGD system.
As a result, an emission rate of 73 ng/J (0.17 lb/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 SO£ emissions and would, in fact, impose no additional emission
control requirements.
An emission rate of 43 ng/J (0.10 lb/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 SO2 emissions. It would
not, however, impose any additional emission control requirements beyond
those imposed by Alternative Control Levels 2 and 3 for standards limiting
SO2 emissions.
12

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An emission rate of 22 ng/J (0.05 lb/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 SO2 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 S0£ 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 S0£ emissions from coal combustion, however,
does result in reduced PM emissions.
Consequently, alternative control levels for standards limiting SO2
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 SOj
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
SO2 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 lb/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

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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 lb/million Btu) for spreader stokers and 190 ng/J
(0.45 lb/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 lb/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 (PMjq). 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 wers
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 SO2/J (1.1 to 1.4 lb SOj/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 lb/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 lb/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
Boiler
capacity, MW
(million otu/hr)
heat Input
percent
ash
Fuel
percent
sulfur
healing value
(Blu/ib) (a)
Test load
range
(percent
or design
capacity)
Boiler
type (b)
Controlled
paniculate
emissions
(Ib/mllilon Btu)
(c)
Percent
of flow
to
baghousi
Gen Motors (DDD)
IS (SO)
9.7
0.8
12,900
68
SS
0.120
16
Gen Motors (EEE-1)
15 (SO)
9.0
1.8
12,400
84-93
SS
0.120
37
Gen Motors (GGG)
20 (70)
4.3
0.9
13,700
78-80
SS
0.120
30
Gen Motors (CCC)
23 (80)
10.1
0.8
11,400
71-80
SS
0.130
31
Gen Motors (EEE-3)
18(60)
8.8
2.1
12,400
99-105
SS
0.142
51
Gen Motors (BBB-3)
18(60)
7.8
0.8
13,100
97-108
SS
0.165
17
Gen Motors (FFF)
29(100)
6.1
1.7
13,100
85-97
SS
0.156
15
Mllllken & Co.
9(31)
7.8
1.3
13,200
100
SS
0.120
NA (d)
(a)	Multiply Btu/lb by 2.323 (or conversion to kJ/kg.
(b)	SS - Spreader stoker.
(c)	Multiply Ib/mlMon 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 lb/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 lb/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
FGO 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 SOg 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 Sl^/J (2.2 to 4.4 lb
SOj/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 lb/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 lb/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 lb/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)
She
Boiler
capacity, MW
(million Blu/lv)
heal Input
Scrubber
lypB (a)
Operating
pro99uro
drop,
kPa
(Inches water)
Boiler
load
(%)
Coal
sulfur
content
(wt. %)
Coal
ash
content
(wt. %)
Contra Uad
particulate
emissions
(Ib/mllllon Btu)
(b)
Plant LL
Boiler 419
69 (236)
VS
4.8(19.3)
73
2.6
11.4
0.10
Plant LL
Boiler 020
69 (236)
VS
4.3 (17.3)
85-91
2.5
10.4
0.07
Plant AAA
37(125)
MVT
1.9 (7.5)
92
1.3
4.4
0.08
(a)	VS » Venlurl scrubber, MVT - multlveniurl tray scrubber.
(b)	Multiply Ih/mUllon Btu by 430 for conversion to ng/J.

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TABLE 4-3. PM EMISSIONS DATA FOR FABRIC FILTERS APPLIED TO
COAL-FIRED BOILERS (19)
Plant
Boilar
capacity, MW
(million Btu/hr)
heat Input
Fuel
percent percent heating value
ash sullur (Blu/lE) (a)
Test load	Controlled
range	particulate
(percent	emissions
ol design	(Ib/mlllon Btu)
capacity)	type (b) (C)
Alr/clolh ratio
(ACFM/sq ft)
design actual
DuPont (EE-2)
19 (64)
6.9
2.8
13,600
9B-100
SS
0.015
3.4
3.4
Formica (J2-4)
19(65)
6.9
0.B
NA (d)
84-96
SS
0.033
2.5
2.3
DuPont (EE-4)
37(125)
7.0
2.6
13,500
77-78
SS
0.010
3.7
2.9
DuPont (EE-5)
45 (1B1)
6.5
2.9
13,800
96
SS
0.028
3.7
3.6
SOHIO
33(115)
12.3
3.6
11.900
71
FBC
0.019
NA
NA
World Carpets
13 (4B)
83
0.6
13,700
74
SS
0.016
NA
NA
California Portland
59 (208)
8.8
0.4
12,200
99
CFB
0.035
NA
NA
(a)	Multiply Btu/lb by 2.323 lor conversion to kJ/kg.
(b)	SS ¦= Spreader stoker, FBC = Fluldlzed bed combustor, CFB = Circulating fluldlzed bed combustor.
(c)	Multiply lb/million Btu by 430 for conversion to ng/J.
(d)	NA = Not available.

-------
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 1n Table 4-3 are spreader stoker
boilers, a bubbling bed FBC unit, and a circulating bed FBC 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 lb/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 lb/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 lb/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/l,000 acfm); the
hot-side ESP operated at SCAs of 1,770 and 2,080 m2/l,000 m^/s (542 and
634 ft2/l,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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TABLE 4-4. PM EMISSIONS DATA FOR ELECTROSTATIC PRECIPITATORS APPLIED TO
COAL-FIRED BOILERS (19)
Plant
Boiler
capacity, MW
(million Btu/hr)
heat Input
percent
ash
Fuel
percent
sulfur
heating value
(Btu/lb) (a)
Test load
range
(percerti
of design
capacity)
Boler
type (b)
Controlled
particulate
emissions
(Ib/mlllon Btu)
(c)
Specific collection area
(sq ft/1000 ACFM)
		
design operating
Monsanto (K-7)
27 (92)
12.0
NA (e)
12,500
103 106
SS
Monsarto (K-8)
35(120)
11.2
1.00
12,500
93-98
SS
Monsanto (K-9)
46(156)
11.4
0.57
11,400
99-102
SS
KVB Plant P
73 (250)
6.6
0.73
13,100
87-89
SS
KVB Plant N (f)
110(375)
8.3
0.54
10,200
76
SS
KVB Plant N (f)
110 (375)
5.4
0.63
10,600
52-59
SS
0.007
132
128
0.006
156
160
0.012
128
128
0.021
349
397
0.044
344
542
0.018
344
634
(a)	Multiply Btu/lb by 2.323 for conversion to kJ/kg.
(b)	SS - Spreader stoker.
(c)	Multiply Ih/mMIJon Btu by 430 for conversion to ng/J.
(d)	Multiply sq ft/1000 ACFM by 3.2729 for conversion lo square melers per 1000 cubic meters per second.
(e)	NA = Not available.
(0 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 mVl.000 m3/s (400 ft^/1,000 acfm) is capable of achieving PM
emission levels ranging from 3 to 19 ng/J (0.006 to 0.044 lb/million Btu) on
small boilers firing low sulfur coal. A hot-side ESP with an SCA of at
2	3	2
least 2,090 m /1,000 m /s (640 ft /l,000 acfm) could achieve emission levels
ranging from 7 to 19 ng/J (0.018 to 0.044 lb/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 lb/million Btu) or less.
4.7 ALTERNATIVE CONTROL LEVELS
As discussed above, in some cases alternative control levels selected
for standards limiting SO2 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 SO2 standards.
Alternative Control Level 1 for standards limiting S0£ emissions from
small coal-fired boilers is 520 ng/J (1.2 lb/million Btu) and is based on
the use of low sulfur coal. Alternative control levels for SO2 standards
based on the use of low sulfur coal will not affect PM emissions. Thus, the
PM emission levels associated with SOj Alternative Control Level 1 are the
PM regulatory baseline emission level of 190 ng/J (0.45 lb/million Btu) for
boilers of less than 8.7 MW (30 million Btu/hour) and 260 ng/J
(0.60 lb/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 lb/million Btu)
or less by using a sidestream separator or to 43 ng/J (0.10 lb/million Btu)
or less by using a wet scrubber. Particulate matter emissions could be
further reduced to a 22 ng/J (0.05 lb/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 SO2 emissions on a
23

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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 1b/m111ion 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 SO^ Alternative Control Level 2, PM
emissions will be reduced to 22 ng/J (0.05 lb/million Btu) or less.
An emission rate of 130 ng/J (0.30 lb/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 lb/million Btu) and 43 ng/J
(0.10 1b/mi111 on 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 SC^ 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 lb/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 SO2 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 SO2 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 SOg standards in considering
alternative control levels for PH 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 lb/million Btu).^3
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 lb/million Btu) for boilers smaller than 8.7 MW (30
million Btu/hr) and 260 ng/J (0.60 lb/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 PMjg removal. These particles
are in the inhalable range and have the greatest potential for adverse
health impacts.
25

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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 lb/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 lb/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 lb/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 relnjection 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 lb/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 lb/million Btu) or less. Therefore, low
pressures drop wet scrubbers are considered demonstrated at 86 ng/J (0.20
lb/million), whereas medium pressure drop wet scrubbers are considered
demonstrated at 43 ng/J (0.10 lb/million Btu).
26

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







Test load
Average
Controlled


Boiler




(percent
operating
particulate

Number
capacity, MW


Fuel
Fuel
of design
pressure
emissions
Plant
of
(million Blu/hr)
Scrubber
Efficiency
sulfur
ash
capacity)
drop
(lb/million Btu
units
heat Input
type
(%)
(wt. %)
(wt. %)
fa)
(Inches water)
(b)
(c)
Champion International (AB2)
1
32(108)
Imp
NA
NA
NA
79
6 8
0.068
Georgia Pacific (AC1)
2
17/17
Imp
NA
NA
NA
63
6-8
0.182


(57/57) (d)







Georgia Pacific (AC2)
1
16(55)
Imp
NA
NA
NA
47
6-8
0.170
Georgia Pacific (AD1)
1
18(61)
Ven
NA
NA
NA
73(e)
6-8
0.182
Georgia Pacific (AG1)
1
50 (170)
Ven
NA
NA
NA
103
6-8
0.169
Georgia Pacific (All)
1
50(170)
Ven
NA
NA
NA
86
6-8
0.212
Georgia PacMIc (AF1)
1
54(185)
Imp
NA
NA
NA
72
6-8
0.100
Georgia Pacific (AE1)
1
54 (185)
Ven
NA
NA
NA
85
6-8
0.131
Georgia Pacific (AH1)
1
63(215)
Ven
NA
NA
NA
65
6-8
0.148
St. Joe Paper (AJ2) (f)
1
50 (170)
VTV
94
0.03
2.2
91
8
0.104
St. Joe Paper (AJ4) (()
1
50(170)
VTV
96
0.01
IB
95
13.5
0.137
St. Joe Paper (AJ5) (f)
1
50 (170)
VTV
NA
NA
NA
91
15.2
0.057
Boise Cascade (AAI)
I
67 (230)
VTV
NA
NA
2 B (g)
95
18
0.048
St. Regis Paper (AK2) (f)
1
61 (210)
Ven
98
0.04
1.7
94
20
0.074
St. Regis Paper (AK3) (f)
1
61 (210)
Ven
NA
0.17
4.2
100
26
0.063
NA - Not available.	(a) Average value during lesling.
Imp « Impingement	(b) Multiply Inches of water by 0.24B6 lor conversion to KPa.
Van «¦ Venturi	(c) Multiply lb/million Btu by 430 for conversion to ng/J.
VTV = Variable Throat Venturi	(d) Two boilers which exhaust Into a single wet scrubber.
(e) Estimated, based on mass emission rale and F-lactor.
(() EPA Method 5 data acquired on EPA lesls.
(g) These data did nol come from an analysis done during amission testing.
They were obtained from Industry sources and are representative of
the typical fuel burned al 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 lb/million Btu). The operating
SCAs ranged from 752 to 1,480 m2/l,000 m3/s (230 to 453 ft2/l,000 acfm).
The emission test data indicate that an ESP with an SCA of at least
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 lb/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 lb/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 lb/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 lb/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 lb/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)
Plant
Control
device
Boiler
capacity, MW
(million Btu/hr)
heat Input
Fuel
%
ash
%
sulfur
healing value
(Btu/lb) (a)
Test load
range
(percent
ol design
capacity)
Boiler
type
Specific collection area Controled
(sq ft/1000 ACFM) particulate
(t>)	emissions
. ,	. (Ib/mlllion Blu)
design operating ' jc) '
Champion International Coop (BA1)
ESP
50 (170)
NA

NA
NA
66
SS
177
230
0.072
Westvaco Bleached Board (BI1) (d)
ESP
108/147 (370/500)
3.4
(e)
0.3
10,750
25/25
SS
296
320
0.042
Westvaco Bleached Board (BB1)
ESP
202 (690)
4.8
(f)
NA
8,250
69
SS
298
453
0.057
Weyerhaeuser Co. (BE2) (g)
EGB
180 (615)
9.4
(h)
0.06
8,270
96
SS
NA
6.0(1)
0.027
Weyerhaeuser Co. (BE3) (1)
EGB
180 (615)
3.8

NA
8,970
101
SS
NA
3 4 (j)
0.025
Weyerhaeuser Co. (BE4) (1)
EGB
180 (615)
3.8

NA
8,910
116
SS
NA
4.0 (J)
0.024
Weyerhaeuser Co. (BE5) (1)
EGB
180 (615)
4.8

NA
8,780
95
SS
NA
5.6 (J)
0.039
Weyerhaeuser Co. (BE6) (1)
EGB
180 <615)
4.6

NA
6,830
107
SS
NA
7.1 (1)
0.051
(a)	Multiply Btu/lb by 2.323 for conversion lo kJ/kg.
(b)	Multiply sq fl/1000 ACFM by 3.2729 for conversion to sq meters per 1000
cubic meters per second.
(c)	Multiply Ib/mllllon Blu by 430 for conversion lo ng/J.
(d)	The flue gas from two bollere pass through Individual mechanical
collectors. It Is then combined into a single duct and split lo enter a
two-chamber ESP with two stacks. The lesl data and emission levels shown are
the weighted average of both stacks.
(e)	Boiler burns low sulfur coal with the wood. The analysis of Ihe coal
showed the following composition: moisture - 5.5%; ash (dry) - 12.4%; sulfur
(dry) - 0.86%.
(h These data did not come from an analysis done during emission testing.
Tney 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 Ihe flue gas.
Each module has a separate slack. The emission levels shown are the weighted
average of all three stacks.
(h) At this facility, char from the first staae of Ihe mechanical collector is
slurried and separated by screens Into larae 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.
a For EGB, this value Is pressure drop In Inches of water. Multiply inches
water by 0.2468 for conversion lo kPa.
NA - not available.
SS a Spreader Sloker.
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 (SO2) 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.t 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 O.T. Waddell, Radian Corporation, to
Copland, R.A. EPA/SDB. 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 completingy
1. REPORT NO. 2.
EPA-450/3—89-11
W§6nt2a5c^T1°5/as
4, TITLE ANO SUBTITLE _ _
Overview of tne Regulatory Baseline, Technical Basis,
and Alternative Control Levels for Particulate Matter
(PM) Emission standards for Small Steam Generating Unit:
¦•fliTW
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO
9. performing organization name and adoress
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 ANO 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.JyP6 OF REPORT AND PERIOD COVERED
Final
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
a. DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. cdsati Fteld/Group
1
| Air Pollution
| Pollution Control
Standards of Performance
Steam Generating Units
Industrial Boilers
Small Boilers
Air Pollution Control

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